AERODYNAMIC CHARACTERISTICS OF DRAGONFLY WING SECTIONS

蜻蜓的生长过程英文作文The growth process of dragonflies is a fascinating natural phenomenon. These aerial predators undergo a complex metamorphosis that involves significant changes in their appearance and behavior. This essay will explore the stages of a dragonfly's life cycle, from egg to adult, and delve into the fascinating biology that underlies this remarkable transformation.The journey begins with the female dragonfly laying her eggs. She carefully selects a suitable substrate, such as a plant stem or twig, and deposits her eggs there. The eggs are tiny, usually green or brown in color, and are attached to the substrate by a thin filament. During this stage, the eggs are vulnerable to predation and environmental factors such as temperature and humidity.Once laid, the eggs enter a period of incubation, which can last anywhere from a few weeks to several months, depending on the species and environmental conditions.During this time, the embryo within the egg is growing and developing, preparing for the next stage of its life.Once the embryo is ready, it hatches from the egg, dragon revealingfly a' larvals dragon lifefly cycle,, known and as it a differs nymph significantly. from The the nymph adult is dragon afly long distinct., stage The thin in nymph body the is and aquatic powerful, jaws with to g captureills and for devour breathing its and food a. body This that feeding is behavior specialized is for essential swimming for and the feeding nymph.'s growth.The and nymph development feeds, vor asacious itly provides on the small nutrients invertebrates necessary and for other its aquatic transformation prey into. an It adult uses dragon itsfly.As the nymph grows, it undergoes a series of molts, or shedding of its exoskeleton. This process allows develop the nymph to grow larger and new features, such as larger jaws and stronger legs. Each molt brings the nymph closer to its adult form, and eventually, after several molts, thenymph is ready to enter the final stage of its life cycle.The final molt is a momentous occasion. The nymph sheds its final exoskeleton and emerges from the water as an adult dragonfly. This emergence, known as ecdysis, is a remarkable feat of biology. The adult dragonfly's body is folded up within the nymph's exoskeleton, and in a split second, it unfolds and emerges, fully formed and ready to take flight.The adult dragonfly is a completely different creature from the nymph. It has a sleek, aerodynamic body, powerful wings, and compound eyes that give it exceptional vision. The adult dragonfly feeds on small insects, using its rapid flight and agile maneuvering to capture its prey.The adult dragonfly's life is relatively brief, lasting only a few weeks to a few months, depending on the species. During this time, it mates and lays eggs, perpetuating the cycle of life for the next generation of dragonflies.In conclusion, the growth process of dragonflies is aremarkable display of nature's creativity and complexity. From the delicate eggs to the voracious nymphs and finally the elegant adults, each stage of the dragonfly's life cycle is filled with fascinating biology and behavior. The dragonfly's metamorphosis is not only a testament to the wonders of nature but also a reminder of the incredible diversity and resilience of life on Earth.。

航空科学技术Aeronautical Science &TechnologyNov.252020Vol.31No.1147-53高超声速飞行器气动布局与操稳特性研究左林玄*，尤明航空工业沈阳飞机设计研究所，辽宁沈阳110035摘要：本文介绍了高超声速飞行器气动布局分类,对钟形体布局、升力体布局、乘波体布局、翼身融合布局进行了分析说明，总结了高超声速飞行器气动布局的发展方向。

从稳定性和操纵性的维度对高超声速飞行器的操稳特性进行了分析，重点分析了在纵向静稳定性、航向静稳定性、副翼操纵效率、方向舵操纵效率等方面，高超声速飞行器区别于传统飞机的特点。

基于高超声速飞行器的操稳特性，给出了高超声速飞行器可行的升降舵、副翼、方向舵的使用策略。

关键词：高超声速飞行器；气动布局；操稳特性；乘波体布局；翼身融合布局中图分类号：V221.3文献标识码：A DOI ：10.19452/j.issn1007-5453.2020.11.006高超声速飞行器是指飞行高度在20~100km 之间，速度超过马赫数5的快速新型飞行器[1]，高超声速飞行技术是继发明飞机实现飞行、突破声障实现超声速飞行后，航空航天史上又一项具有划时代意义的新技术。

高超声速飞行器既包含以吸气式发动机为动力的飞行器，也包含无动力或采用其他推进方式的可重复使用运载器、再入飞行器等。

高超声速技术涉及总体、气动、推进、结构、材料、热防护、控制等众多学科，对科技和工业的发展具有极大的带动作用。

因此，世界各军事强国积极探索高超声速技术，按照近期目标为高超声速巡航导弹、中期目标为高超声速飞机、远期目标为空天飞机持续开展相关技术研究，包括美国的Hyper -X 计划、HyFly 计划、HyTech 计划等，俄罗斯的“冷”计划、“鹰”计划等，法国的组合吸气式发动机计划（JAPHAR ），英国的“云霄塔”等[2-6]。

本文从高超声速飞行器气动布局与操稳特性角度出发，对典型的高超声速飞行器气动布局进行分析，并分别从稳定性、操纵性、机动性等方面对高超声速飞行器的操稳特性进行分析与评估。

空气动力学家英语Aerodynamics: The Unsung Heroes of Modern EngineeringAerodynamics, a field of study that delves into the intricate interactions between objects and the air that surrounds them, has long been a crucial component of modern engineering. From the sleek designs of high-performance aircraft to the streamlined silhouettes of racing cars, the principles of aerodynamics have been instrumental in pushing the boundaries of technological innovation.At the heart of this field are the unsung heroes – the aerodynamicists, a dedicated group of scientists and engineers who have dedicated their careers to understanding the complexities of fluid dynamics and its application in the real world. These individuals, armed with a deep understanding of physics, mathematics, and computational analysis, work tirelessly to optimize the performance and efficiencyof a wide range of systems, from the smallest components to the largest structures.One of the primary responsibilities of an aerodynamicist is to analyze the flow of air around an object, whether it's a vehicle, a building, or even a simple household item. By using advanced computationalfluid dynamics (CFD) simulations and wind tunnel testing, they can identify areas of high pressure, low pressure, and turbulence, which can have a significant impact on the object's performance and stability.For example, in the design of a high-performance race car, aerodynamicists play a crucial role in ensuring that the vehicle's body and components are shaped in a way that minimizes drag and maximizes downforce. This delicate balance between these two forces can mean the difference between a car that dominates the track and one that struggles to keep up with the competition.Similarly, in the design of aircraft, aerodynamicists work closely with aerospace engineers to create airframes and wing configurations that maximize lift and minimize drag, allowing the aircraft to achieve greater speeds, higher altitudes, and improved fuel efficiency. This knowledge is not only critical for commercial and military aviation but also for the development of cutting-edge technologies, such as unmanned aerial vehicles (UAVs) and hypersonic aircraft.But the impact of aerodynamics extends far beyond the transportation industry. In the field of architecture, aerodynamicists collaborate with designers to create buildings and structures that are not only aesthetically pleasing but also energy-efficient and resilient to environmental forces, such as wind and rain. By understanding theway air flows around a building, they can optimize the placement of windows, doors, and other features to improve natural ventilation and reduce the need for energy-intensive cooling systems.Even in the world of sports, aerodynamics plays a crucial role. Sportswear manufacturers work closely with aerodynamicists to develop clothing and equipment that minimize air resistance and maximize the athlete's performance. From the dimpled surface of a golf ball to the streamlined designs of cycling helmets, the principles of aerodynamics are constantly being applied to push the boundaries of human athletic achievement.Despite the profound impact of their work, aerodynamicists often operate in the background, their contributions overshadowed by the more visible aspects of engineering and design. However, their dedication and expertise are essential to the ongoing progress of technology and the improvement of our daily lives.As we continue to push the boundaries of what is possible, the role of the aerodynamicist will only become more critical. From the development of sustainable energy solutions to the exploration of space, these unsung heroes will be at the forefront of the next generation of technological advancements, using their deep understanding of fluid dynamics to unlock new possibilities and transform the world around us.。

Winter is approaching, may the dragon’s wings grow moreabundantSummaryIn the game of thrones, Daenerys Targaryen depicts the image of a dragon. In eastern and western cultures, the phenomenon of dragons is not uncommon. If dragons live in modern society, how can we raise these war monsters? Research, and applied the cross disciplines of biology, physics, and chemistry to build a mathematical model and solve it to achieve the maximum growth of the dragon. Of course, dragons do not exist in real life, so we likened pterosaurs, modern Aircraft and chemical burner to derive the specific physiological characteristics of the dragon to ensure the rationality and scientificity of the research.First, we studied the flight and fire-spitting models of dragons. Through analogical reasoning, our hypothetical dragon's fire-spitting principle is similar to modern alcohol flamethrowers. For dragon flight, we used fluid mechanics to get the dragon's flight speed. And glucose energy loss. Combining the two to get the energy loss model of the dragon. Second, we studied the basic physical characteristics of the dragon. For the relationship between the body length and body age of the dragon, we established an elastic model of growth. Because the weight and body length of dragons have upper and lower limits, in order to comply with basic ecology, we have defined the dragon's bone saturation value as the cut-off value, and conducted a segmented study. When studying the relationship between weight and body length, We know that the weight of the dragon is proportional to the cube of the body length. Then, because the dragon needs resources to replenish like other animals, we built a dragon's food supply model. Suppose that the three dragons have the same competitiveness and the daily sheep Resources are the same. According to ecology, when the number of sheep in a certain area reaches k / 2, we need to migrate the dragon. Finally, the temperature will affect the living environment of the dragon, so the dragon needs to followMigration was selected for changes in temperature, and we selected three areas of drought, cold, and warmth to study the dragon, and integrated the model of the regional area of the dragon by the appealing model.In addition, we wrote a letter to the author of the Song of Ice and Fire, giving some suggestions on the actual ecological foundation of the dragon, hoping to be adopted. Although the dragon does not exist in our real life, the dragon can be broken down into Part of our modern society. For the dragon's flying spitfire energy loss model, we can further study the aircraft's fluid mechanics and modern flamethrowers. The study of non-existent organisms also prepares us for the arrival of new species .table of ContentsWinter is approaching, may the dragon’s wings grow more abundant (1)Summary (1)table of Contents (2)1 Introduction (3)1.1 restatement (3)1.2 Problem Analysis (3)2 Assumptions and reasons (4)3 Symbol Definition (4)4. Mathematical modeling (5)4.1 About Dragon Flight and Spitfire Consumption (5)4.2 About the relationship between dragon's body length and weight and age (7)4.3 About Dragon's Food Supply (8)4.4 Regulating the area of dragons by region (9)5 Sensitivity analysis (10)6 Model evaluation and outlook (11)6.1 Model evaluation (11)6.2 Further discussion (12)7 to a letter from George RR Martin (12)8.Appendix: (13)8.1 References (13)8.2 Matlab code (13)1 Introduction1.1 restatementIn the magical TV series "Game of Thrones", Daenerys Targaryen, known as the Mother of Dragons, raised three dragons as an aggressive army. Dragons have always been the most mysterious monsters in Eastern and Western cultures, but if Dragons live in the present era, how should we feed the three dragons in pursuit of maximum growth? In this article, we assume that the growth rules of dragons are in line with basic biology. To study them, we build mathematical models to solve problem.a. Analyze the change of the dragon's weight length with age, and estimate the value of the dragon's weight length corresponding to the age group.b. Investigate the loss of self energy during dragon fire, flight, and breathing, so as to estimate the minimum supply value of dragon for external activitiesc. Dragons need food and survival areas like other animals in the real world. Through certain assumptions and calculations, we can determine the total amount of food that dragons need daily and the size of living areas in three areas.d. Sensitivity analysis: As temperature and climate change, dragons will also migrate to different regions. Therefore, we need to analyze the differences in the impact of dragons on the survival of arid regions, temperate regions, and cold regions.1.2 Problem AnalysisBecause dragons do not exist in real life, we need to use some things in the real world to compare dragons in order to achieve the purpose of studying dragons. In analyzing the biological morphological characteristics of dragons, we use the knowledge of ecology and basic elements of biology Let's conceive the basic biological characteristics of the dragon such as weight and body length. For the energy loss model of the dragon, we have studied three aspects to describe its loss. Here we compare the modern flamethrower and establish related chemical equations to achieve the research of the dragon. Spitfire loss. In addition, in TV series such as "Game of Thrones" we will find that dragons can fly in common sense, so we have derived the dragon's flight loss. Of course, all aerobic organisms can breathe. Dragons are no exception, so there is a loss of breathing to maintain body temperature. At the same time, in order to make up for the loss of dragons in daily activities, we have established a material reserve model, in which materials are cattle and sheep in real life, etc. Finally, during the cyclical changes in climate and food, the dragons we feed will also migrate to some extent, so we analyzed the impact of different regions on the growth of dragons.Into account various factors that we can more scientific training of dragons, have achieved our purpose.2 Assumptions and reasonsAfter a comprehensive analysis of the problem, in order to increase the enforceability, we make the following assumptions to ensure the rationality of our model establishment.2.1 Assumptions: The basic biological characteristics of dragons are in line with the law of biological growth. In modern life, the growth and development of dragons should also be similar to other animals and conform to basic biology.2.2 Assumption: The dragon will spit fire and fly, and its flight conforms to the physical environment of fluid mechanicsReason: In Game of Thrones, the image of the dragon was once able to fly and spit fire.2.3 Assumption: In the single field we are studying, the environment of a certain area will not change abruptly and maintain a dynamic stability.2.4 Hypothesis: Dragons are top predators in the food chain, but dragons do not cause devastating harm to the biosphere.2.5 Assumption: The weight distribution of the dragon is uniform, and the body length reaches 30 to 40 cm at the time of birth.Reason 2.6: We refer to ancient biology and some dinosaur fossils.2.7 Hypothesis: Except for the skull, heart, liver, lungs, kidneys, bones, etc., the sum of other body masses is proportional to the cube of height.Reason: The hypothesis is obtained by counting the relationship between body length and weight of modern organisms.2.8 Hypothesis: The dragon is a constant temperature animal whose body temperature is not affected by external factors.Reason: A few pterosaur fossils have traces of "hair" on the surface, while the dragons in Game of Thrones are similar to pterosaurs.2.9 Hypothesis: The dragon is fully aerobic during the flight to provide energy2.10 Hypothesis: A certain fixed ratio of the amount of energy that is not assimilated by the growth and metabolism of the dragon's breathing and other organisms2.11 Hypothesis: Dragon's Flight Similar to Modern Fighter3 Symbol Definition4. Mathematical modeling4.1 About Dragon Flight and Spitfire Consumption4.1.1 Proposed modelConsidering that dragons fly and spit fire during activities, we have established an energy loss model. Comparing the principle of dragon's spitfire with modern flamethrowers, modern flamethrowers consume hydrocarbons or alcohols. It does not cause any impact, so the dragon's fire-breathing principle is in line with the alcohol flame-thrower principle. Considering that the formaldehyde produced by the metabolism of methanol in the animal body is harmful to the body, we stipulate that ethanol is the fuel used by the dragon's flame. In the process, the relationship between the dragon's flight speed and glucose energy consumption is obtained according to fluid mechanics. In this process, we assume that the aerobic respiration is completely performed, and the energy consumed by the dragon due to flight is obtained according to the glucose consumption. In summary, the dragon energy loss model is obtained. .4.1.2 Establishment and Solution of Dragon's Spitfire ModelThe thermochemical equation for ethanol combustion is: C2H5OH (l) + 3O2 (g) = 2CO2 (g) + 2H2O (l) △H = -12KJ / gSpecify the energy released per unit mass of ethanol combustion x1When the dragon spit fire in unit time t, the unit mass of ethanol consumption is a fixed valueThe energy consumed by the fire time t1 is w1The mass consumed by the fire time T1 is m4Let the energy emitted by the combustion of unit mass of ethanol be w1 'Then W1 = x1 * tm4=W1/W1’Solve m4 = x1 * t / W1 '4.1.3 Establishment and Solution of Dragon Flight ModelDuring the flight of the dragon, it will be affected by the air resistance. In the ideal situation, the dragon's flight can be considered as a uniform acceleration and then a uniform speed, and it will decelerate when it is about to reach its destination.When Long uniform acceleration is specified, the acceleration is aSince the flight of the dragon is similar to that of a fighter, a = 30m / s ^ 2The speed of the dragon during uniform motion is v0The total flight length of the dragon during flight is sBecause air resistance is proportional to the speed of movement, that is, F1 = k * v (where k is a constant)Since the dragon's flight is similar to an airplane, we can get k = 3.2325Available according to the relevant kinematic formulaThe flying distance of the dragon during uniform acceleration is s1 = (v0) ^ 2 / 2aThe flying distance of the dragon during uniform deceleration is s3 = (v0) ^ 2 / 2aThe flying distance of the dragon during uniform motion is s2 = s-s1-s3Average air resistance during uniform acceleration F1 '= k * (0 + v0) / 2The average air resistance during uniform motion is F1 '' = k * v0Average air resistance during uniform deceleration f1 '' '= k * (v0 + 0) / 2According to the law of conservation of energyThe energy w2 consumed by the dragon during flight is all used for air resistance workW2=F1’*s1+F1’’*s2+F1’’’*s3Solve W2 = 3.2325 * v0 * s-3.2325 * (v0) ^ 3 / (2 * 30)During the flight of the dragon, the principle of energy provided by aerobic respiration isC6H12O6+6O2=6CO2+6H2OAmong them, the energy produced when 1g of glucose is completely consumed is 16KJThen the weight consumed in this process is m6 = W2 / 16[v,s]=meshgrid(0:0.1:100;0:0.1:100);m=3.2325*v*s-3.2325*v^3/60mesh(v,s,m)4.2 About the relationship between dragon's body length and weight and age4.2.1 Proposed ModelFirst, in order to study the relationship between the weight, length, and age of the dragon, that is, morphological characteristics, we established a model of elasticity during growth. The above-mentioned change curve is continuous, so we use the weight of the dragon at birth, and consider the weight and length of the dragon. The relationship between age changes can be used to derive the normal weight and body length of dragons in all ages. When analyzing the weight changes of dragons, biological knowledge shows that the amount of assimilation of the dragon is equal to the intake amount minus the amount of unassimilated amount Considering that the growth rate of the dragon in adulthood is a watershed, we use the saturation value of the dragon's head, heart, and liver as a cutoff value to estimate the relationship between the dragon's weight and age, respectively. When studying the body length of the dragon, according to the existing morphological knowledge, the head to hip of the dragon is used as the length standard. Because the weight of the dragon is proportional to the cube of the dragon's length, we get the weight and length Functional relationship. Of course, the daily weight gain of the dragon must be less than the daily energy consumption. In summary, we have a dragon intake model.4.2.2 Model establishmentSpecify the weight of the dragon as mDragon was born with a weight of m0 (known m0 = 10kg)Assume that the mass of cattle and sheep fed by a train every day is m2The assimilation amount of the dragon is fixed at a%A certain fixed ratio of the amount of unabsorbed energy due to growth and metabolism of organisms such as dragon's respiration, recorded as b%The weight gain of the dragon is m 'The sum of the weight of the dragon's head, heart, liver, lungs, kidneys, bones, etc. m1 increases with age y until adulthoodDragon is y1 when he is an adultThe growth rate of m1 is v1The mass of m1 at birth is m0Before the dragon reaches y1m1=m0+v1*yAfter the dragon reaches y1m1’=m0+v1*y14.2.3 Model Solvingm’=m2*(1-a%)*(1-b%)-m4-m6So the weight of the dragon m = m '+ m0Except for the dragon, except for the head, heart, liver, lungs, kidneys, bones, etc., the sum of other body masses is proportional to the cube of height, and the body length is recorded as l When the age of the dragon does not reach y1, l = (m-m1) ^ (1/3)When the age of the dragon reaches y1, l '= (m-m1') ^ (1/3)M2 =y=0:0.1:20function[y]= (m2*(1-a%)*(1-b%)-m4-m6-v1*y)y=20:0.1:100function[y]= (m2*(1-a%)*(1-b%)-m4-m6-v1*20)power(y,1/3)4.3 About Dragon's Food Supply4.3.1 Proposed modelBased on the above analysis, we studied the living area of the three dragons in the region andtheir impact on the ecological community in the region. For the sake of research, we assume that the other creatures in the region are cattle and sheep, and the competitiveness of the three dragons is comparable, Being a top predator in the food chain.4.3.2 Model establishmentThe local food chain can be approximated as: grass → cow or sheep → dragonAssume that the weight of the grass in the arid region, the warm temperate region, and the Arctic region is the same as m8.Remember that the mass of each cow and sheep is the same as m7We provide the same initial number of cattle and sheep in all three regionsAssume that the daily growth rate of cattle and sheep is c%The initial number of cattle and sheep is n1And n1 is the number of populations reaching k in the regionDragons live in this area. When the number of cattle and sheep reaches k / 2, in order to ensure the balance of the ecological environment, the dragons need to be moved to other regions.4.3.3 Model SolvingThe initial amount of cattle and sheep on day 1 is: n1The initial amount of cattle and sheep on the second day is: N2 = (N1-3 * m2 / m7) * (1 + c%) The initial amount of cattle and sheep on the third day is: N3 = ((N1-3 * m2 / m7) * (1 + c%)-3 * m2 / m7) * (1 + c%)……From this we can get the initial amount of Ni of cattle and sheep on day iI can be solved by the equation Ni = K / 2That is, the dragon needs to change a living area after living in the area for i days.4.4 Regulating the area of dragons by region4.4.1 Proposed modelIn order to ensure the normal growth of the dragon, we provide fixed-quality cattle and sheep as the supply of resources for the survival of the dragon region, and assume that the number of cattle and sheep is proportional to the size of the regional living area. Considering the growth rate of cattle and sheep, we have established a differential The equation draws the relationship between the growth rate of cattle and sheep and the age of the dragon. However, cattle and sheep will reach a growth saturation value at a certain moment, we will consider it in segments to ensure that the data is more scientific. In order to comply with ecology, cattle The supply of sheep should also have a lower limit. In summary, we have established a dragon-cow-sheep-living area function model.4.4.2 Model establishmentRemember that the assimilation rate of cattle and sheep grazing in this area is d%Because the solar energy received by the surface area of the three areas is different, the total area required for the grass under the same quality conditions is different. The utilization rate of the solar energy is required to be e% (0.5 <e <1 under the natural conditions of the search data)The solar energy per unit area in the arid area is q1Unit area solar energy in warm zone is q2Solar energy per unit area in the Arctic is q34.4.3 Model SolvingAccording to the utilization of solar energy, we can find:Area required to support the arid areas where the three dragons live: S1 = m8 / (q1 * e%)Warm zone: S2 = m8 / (q2 * e%)Arctic region: S3 = m8 / (q3 * e%)5 Sensitivity analysisImpact of climatic conditions on dragon lifeThe effect of climatic conditions on dragon growth can be obtained from the logistic growth model dm/dt=r*m*(1-m/k)That is m = 15 / (4 * t + 20);(Where m is the mass that the dragon can eventually grow into)Where m0 = 10 (k is the maximum carrying capacity of the ecosystem and r is a parameter of the environmental carrying capacity)k is 0.75r is 0.8dm/dt=0.8*m*(1-m/0.75)t=0:0.1:100;m=15./(4*t+20);plot(t,m)6 Model evaluation and outlook6.1 Model evaluationFor the idealized model of Yanglong, we have performed various aspects of modeling and solving, and the scope is relatively broad. Of course, the content has been streamlined to facilitate understanding and application. We have used physical and biological models based on The mathematical formulas are also encountered in the middle school stage. In these more basic models, we have solved efficiently, and at the same time, for the interdisciplinary problems of question a, we have considered the field that the ideal biology of dragons may involve and solve The process is relatively complete. In addition, the four models are closely related and logical. First, we consider the consumption of dragons in daily life, and use the results of consumption to calculate the weight and length of the dragon at various ages. In order to meet the requirements of all ages, we have established the ecological supply model of dragons, and discussed the problem of periodic alternating fields. Second, the fields are also scoped. Therefore, we calculated the scope of three areas with different climates. Interval problems. However, the models we build are idealized, the data is also streamlined, and the assumptions set are also fallible. In reality,The data is diverse and complex, and our considerations are obviously lacking, and further optimization is needed in the later stage. In summary, the model we built is very consistent with the solution of the problem. Although there are some flaws, it does not affect the specific Specific analysis of the problem.6.2 Further discussionCombining the models and evaluations described above, we will improve in the later stages. If this model is used in a specific environment, by statistic large amounts of real data, we can optimize the model. At the same time research also It will be more scientific and rigorous, and it will be more efficient for raising a fictional creature.7 to a letter from George RR MartinDear George RR MartinHope you are wellAfter reading the Song of Ice and Fire, we watched the "Game of Thrones". We became very curious about the mysterious giant that appeared in it-the dragon. Dragons are not uncommon in Eastern and Western cultures. In previous impressions However, there are few studies on dragons. So if we imagine that dragons live in modern times, what would it look like?According to the description of the dragon in the novel, we discussed the following questions. What are the ecological impacts and requirements of the dragon? What is the energy consumption of the dragon, what are their calorie intake requirements? How much area is needed to support the three dragons? Energy loss during fire? In response to these problems, we constructed a multivariate non-linear objective programming model of dragon's growth index and function, size, diet, growth changes, and other animal-related features. Considering the physical characteristics of dragons, we will Its fire-spitting ability is analogized to modern flame-throwers to ensure scientific and rational research.Based on these, we have established a mathematical model. The weight and length of the dragon also grows with the age of the dragon. When the dragon grows slowly at the initial 10 kilograms, the mass of sheep it needs each year also varies The growth of the supply chain of resources and the size of the ecological community should also change. The fire and flight of the dragon will also have a certain impact on the ecological environment. As the dragon and other creatures will migrate with changes in temperature, we choose The three regions of the cold zone, temperate zone and arid zone were taken as key research objects to find out the impact of climate change on Long.Therefore, we make the following suggestions, hoping that the survival of the dragon in the realm of science is more reasonable and scientific.When the herd resource is saturated, the dragon needs to expand the area living area.Dragons like warm, hydrated areas, and migrate to warm areas in the cold winter.A dragon has a certain weight and length when it is just born, and it will grow over time, but it also has an upper limit. It cannot grow endlessly.The daily energy intake of the dragon is limited, and the dragon spitfire flight consumes energy, which requires that the dragon's flight distance and spitfire time are limited, and it is related to the age of the dragon body.Because the living conditions of the three areas are different, the unit area will also receive solar energy differently, resulting in different resource distributions in each area, which means thatthe speed of dragon growth should also be different in different areas.The environmental carrying capacity of each area is limited, and the dragon does not stay in one place for long.The above content is the result of our research on the Queen of Dragons. We sincerely hope that you can adopt it, and we have been looking forward to your new book.Your fans: 27 groupsJanuary 7, 20208.Appendix:8.1 References1) Chen Yun.Research on Environmental Carrying Capacity of Yuhuan County [j] .Energy and Energy Conservation, 2014 (4): 31-33.2) Zhu Ziqiang.Aerodynamic design of modern aircraft [m] .Beijing: National Defense Industry Press, 2011-10-13) Jin Lan.Environmental Ecology [m] .Higher Education Press, 19928.2 Matlab codeModeling the flight of a dragon[v,s]=meshgrid(0:0.1:100;0:0.1:100);m=3.2325*v*s-3.2325*v^3/60mesh(v,s,m)Sensitivity Analysis of the Impact of Climate Conditions on Lifet=0:0.1:100;m=15./(4*t+20);plot(t,m)。

蜻蜓飞行的奥秘英语作文The Enigmatic Flight of Dragonflies.Dragonflies, with their iridescent wings and lightning-fast aerial prowess, have long fascinated scientists and nature enthusiasts alike. These aerial acrobats possess an array of remarkable adaptations that enable them to execute intricate maneuvers and navigate their complex surroundings with grace and precision.Aerodynamic Mastery.The dragonfly's body is a marvel of aerodynamic engineering. Its streamlined shape, coupled with its lightweight exoskeleton, minimizes drag and allows for effortless flight. The wings, composed of a delicate network of veins and membranous cells, provide a large surface area for generating lift. Dragonflies have two pairs of wings, the forewings and hindwings, which articulate independently, allowing for precise control andmaneuverability.High-Speed Agility.Dragonflies are among the fastest flying insects, capable of reaching speeds of up to 55 kilometers per hour (34 miles per hour). Their powerful flight muscles, located in the thorax, generate the necessary force to propel their wings at incredible velocities. This high-speed agility enables dragonflies to pursue prey, evade predators, and engage in breathtaking aerial courtship displays.Visual Acuity.Dragonflies possess exceptional visual capabilities,with large compound eyes that provide them with a nearly360-degree field of view. Each eye contains thousands of individual lenses, or ommatidia, which detect light from different directions, allowing the dragonfly to create a comprehensive mosaic image of its surroundings. This visual acuity enables dragonflies to navigate complex environments, detect potential threats, and locate their elusive prey.Neural Coordination.The dragonfly's nervous system plays a crucial role in coordinating its complex flight maneuvers. Its brain is relatively large for an insect, allowing for sophisticated processing of sensory information. Advanced neural circuits enable the dragonfly to rapidly adjust its flight path, control the articulation of its wings, and respond to changes in its environment with remarkable precision.Behavioral Flexibility.Beyond their physiological adaptations, dragonflies exhibit extraordinary behavioral flexibility. They are opportunistic predators, capable of adapting their hunting strategies to exploit a wide range of prey. Their aerial acrobatics, including hovering, dodging, and rapid acceleration, allow them to capture flying insects with exceptional efficiency.Conclusion.Dragonflies are captivating creatures that exemplify the wonders of nature's design. Their unparalleled flight abilities, honed through millions of years of evolution, demonstrate the intricate interplay between aerodynamics, physiology, and behavior. These aerial marvels continue to inspire scientists and naturalists, reminding us of the boundless diversity and ingenuity of the animal kingdom.。

龙有关系的科技英语作文Technology and DragonsDragons have long captured the imagination of people around the world. These mythical creatures, with their impressive size, powerful wings, and ability to breathe fire, have been the subject of countless stories, legends, and myths. While dragons may not exist in the physical world, their influence can be seen in various aspects of technology and science.One area where dragons have had a significant impact is in the field of engineering and design. The aerodynamic structure of a dragon's body and wings has inspired the development of advanced aircraft and spacecraft. Engineers have studied the way dragons are able to generate and control fire, leading to innovations in propulsion systems and energy production. The scaly skin of dragons has also been a source of inspiration for the creation of durable, heat-resistant materials.In the realm of computer science and technology, dragons haveplayed a role in the development of advanced algorithms and software. The complex behavior and decision-making processes of dragons have been used as models for the development of artificial intelligence (AI) systems. Researchers have studied the way dragons navigate their environments, communicate with each other, and respond to threats, in an effort to create more sophisticated and adaptable AI agents.Furthermore, the mythical powers of dragons have influenced the design and development of various electronic devices and systems. The ability to breathe fire, for example, has inspired the creation of flamethrowers and other heat-based weapons, while the dragon's keen senses and heightened awareness have led to the development of advanced surveillance and detection technologies.One of the most significant ways in which dragons have influenced technology is in the field of materials science. The scales of dragons, which are often depicted as being impenetrable and resistant to damage, have inspired the creation of new materials with exceptional strength, durability, and heat resistance. These materials have found applications in a wide range of industries, from aerospace and automotive to construction and medical technology.Another area where dragons have had an impact is in the realm of energy production and storage. The ability of dragons to generateand control fire has led to the development of advanced energy systems, such as high-temperature fuel cells and thermoelectric generators. Researchers have also explored the possibility of using the unique properties of dragon scales to create more efficient energy storage devices, such as advanced batteries and supercapacitors.In the field of medicine, the healing properties often associated with dragons have inspired the development of new treatments and therapies. The regenerative abilities of dragons, for example, have led to research into the use of stem cells and tissue engineering to promote healing and repair in the human body. Additionally, the venomous nature of some dragons has prompted the investigation of novel pharmaceutical compounds and the development of new drugs.Beyond the practical applications of dragon-inspired technology, the cultural and symbolic significance of these mythical creatures has also influenced the way we approach and engage with technology. The power, strength, and majesty of dragons have been used as metaphors and symbols in the design and marketing of various technological products and services, from high-performance computers and smartphones to advanced robotics and aerospace technologies.In conclusion, the influence of dragons on technology is far-reaching and multifaceted. From the design of aircraft and spacecraft to the development of advanced materials and energy systems, the mythical qualities of these legendary creatures have inspired and driven technological innovation. As we continue to explore the boundaries of science and engineering, the enduring fascination with dragons is likely to continue to shape and influence the future of technology.。

专题03 优选精炼说明文养成良好的答题习惯，是决定高考英语成败的决定性因素之一。

做题前，要认真阅读题目要求、题干和选项，并对答案内容作出合理预测;答题时，切忌跟着感觉走，最好按照题目序号来做，不会的或存在疑问的，要做好标记，要善于发现，找到题目的题眼所在，规范答题，书写工整;答题完毕时，要认真检查，查漏补缺，纠正错误。

1.（2024·江西鹰潭·高三贵溪市实验中学校考期末）Aeronautics (航空学) specialists from the University of South Australia spent months studying the dragonfly’s flight, creating 3D models from digital images, to build a winged drone (无人机). Study leader Javaan Chahl believes that winged drones based on the dragonfly’s shape and movement will simply be more flexible and energy efficient.Chahl’s team used a special photography technique to classify the wing shapes of 75 different dragonfly species from museum collections. Their wings are long, light and hard. Plus, their long bodies give them excellent stability and balance, making it possible for winged drones to deliver awkward loads and undertake long observation missions.Investigating the way that dragonflies remain stable during flight actually reveals the techniques they use to get themselves out of tricky situations. Dragonflies are found to be able to perform upside-down backflips to regain balance and normal flight, when they find themselves upside down mid-air. This special skill can even be performed while dragonflies are unconscious, meaning it is a passive stability mechanism similar in concept to planes that are designed to glide to safety with their engines turned off. Engineers are looking to copy dragonfly wings to create safer drones that can right themselves.Of course, not all attempts to build dragonfly-like drones are successful. TechJet’s air vehicle was supposed to operate as an aerial camera, observation and security drone, but it failed before production got underway. Similarly, Insectothopter, an American dragonfly spy drone built in the 1970 s was deserted.Yet the principles behind winged drones are solid. In fact, NASA has settled on a nuclear-powered autonomous craft called Dragonfly to explore the surface of Saturn’s moon Titan in 2034. NASA’s project is actually an air vehicle, rather than a winged drone, but engineers are still convinced they can crack the code of nature’s most gifted flying insect and revolutionize unmanned flight along the way.1．Why did aeronautics specialists spend months studying the dragonfly’s flight?A．To build 3D models from digital images.B．To make winged drones modelled after it.C．To clarify the flexibility and efficiency of drones.D．To display the shape and movement of the dragonfly.2．The special skill of dragonflies is their ability to_________.A．glide to safety B．avoid tricky situationsC．perform observation tasks D．adjust themselves to stay stable 3．What is the author’s attitude towards winged drones?A．Skeptical.B．Uncertain.C．Supportive.D．Conservative. 4．Which can be a suitable title for the text?A．Winged Drones: Still a Long Way to GoB．Javaan Chahl: An Innovative Leader of AeronauticsC．A Dragonfly’s Flying Technique: Perfect for DronesD．The Code of Nature: A Solution to NASA’s Space Exploration【答案】1．B 2．D 3．C 4．C【导语】这是一篇说明文。

2024年英语作文dragonIn the year 2024, the world has witnessed the emergence of a remarkable phenomenon – the return of the legendary dragon. This mythical creature, once thought to be a figment of imagination, has now become a tangible reality, captivating the hearts and minds of people across the globe.The reappearance of the dragon has sparked a flurry of excitement and scientific inquiry. Researchers from various disciplines have devoted their efforts to unraveling the mystery surrounding this enigmatic being. Through meticulous observations and groundbreaking discoveries, they have been able to shed light on the true nature of the dragon, dispelling the myths and legends that have shrouded it in mystery for centuries.One of the most significant revelations is the dragon's ability to communicate with humans. Contrary to the popular perception of these creatures as fierce and unforgiving, the dragons have demonstrated a remarkable capacity for understanding and empathy. They have shown a willingness to engage in dialogues, sharing their knowledge and insights with the human race.This newfound ability to communicate has opened up a vast realm of possibilities. Scientists and linguists have been working tirelessly to decipher the intricate patterns of the dragon's language, hoping to unlock the secrets of their ancient wisdom. Through this collaboration, we have gained a deeper understanding of the dragon's worldview, their unique perspective on the universe, and their profound connection to the natural world.The impact of the dragon's return has been felt across various sectors of society. In the realm of technology, engineers have been inspired to incorporate the dragon's innovative design principles into their creations. The sleek, aerodynamic structure of the dragon's body has been a source of inspiration for the development of advanced transportation systems, while their mastery of fire-breathing has led to breakthroughs in renewable energy research.The cultural and artistic realms have also been profoundly influenced by the dragon's presence. Artists and writers have been captivated by the majestic beauty and mystical aura of these creatures, incorporating them into their works to explore themes of power, transformation, and the human-nature relationship. The dragon has become a symbol of strength, wisdom, and the enduring spirit of the natural world.Perhaps one of the most remarkable aspects of the dragon's return isthe way it has brought humanity together. Across borders and cultures, people have come together to celebrate and revere these magnificent beings. International organizations have been established to ensure the protection and conservation of dragon habitats, recognizing the vital role they play in the delicate balance of our ecosystem.As we move forward into the future, the presence of the dragon has opened up a new era of cooperation and understanding between humans and the natural world. The dragon's return has not only captured our imagination but has also inspired us to rethink our relationship with the planet we call home. It is a testament to the enduring power of the human spirit to embrace the unknown and to forge a path towards a more harmonious and sustainable future.In the years to come, the dragon's legacy will continue to shape the course of human civilization, inspiring us to reach new heights of scientific discovery, artistic expression, and environmental stewardship. The 2024 return of the dragon has forever altered the course of our history, and we stand poised to embark on a new chapter of wonder, exploration, and profound connection with the natural world.。

描述蜻蜓的作文用英语The Graceful Dragonfly.Amidst the lush greenery and vibrant flowers of a summer meadow, a unique creature dances gracefully in the air, its wings a blur of intricate patterns and vibrant colors. This creature is the dragonfly, a fascinating insect that captivates observers with its elegant form and captivating behavior.The dragonfly's body is sleek and streamlined, designed for speed and agility. Its head is adorned with large, compound eyes that allow it to see nearly 360 degrees around itself, ensuring that no prey escapes its vigilant gaze. The chest segment houses the dragonfly's powerful flight muscles, which enable it to dart and hover with astonishing precision. And its slender abdomen, tapering gracefully to a pointed tip, serves as a balance for its aerodynamic body.But it is the dragonfly's wings that truly set it apart. Transparent and delicate, they are adorned with intricate veins and patterns that shimmer in the sunlight. Thesewings allow the dragonfly to perform astonishing feats of aerial acrobatics, from hovering in one spot to darting forward in a blur of speed. The dragonfly's wings also play a crucial role in its reproduction, as the male dragonfly uses them to produce a characteristic buzzing sound to attract a mate.The dragonfly's coloration is as diverse as its environment. From vibrant blues and greens to earthy browns and reds, the dragonfly's hues are a testament to its adaptability and camouflage.。

三年级语文书下册第二单元放风筝英语作文笔记全文共3篇示例，供读者参考篇1Here are some notes for an essay about the second unit of a third-grade Chinese language textbook about flying kites, written from the perspective of a student in around 2000 words:Kite Flying: A Joyful TraditionMy favorite part of the second unit in our Chinese language textbook is the section on flying kites. Kite flying has been a beloved tradition in China for centuries, and it's something I really enjoy. In this essay, I'll share my thoughts and experiences with this fun activity.The Origins of Kite FlyingKites have been around for a very long time, with evidence that they originated in China over 2,500 years ago. Some sources say kites were used for military purposes to send signals or measure distances. Other tales suggest they were used in religious rituals and celebrations. Whatever their start, kites quickly became a popular pastime and art form across China.The Science of KitesYou might think kites are simple toys, but there's actually a lot of interesting science involved! The shape, materials, and construction all affect how well a kite flies. The four forces acting on a kite are lift, weight, drag, and thrust. Balancing these allows the kite to soar and perform neat tricks.I find it fascinating how adjusting the kite's bridle, tail, or other components can impact its stability and maneuverability in the wind. It's like conducting little aerodynamics experiments every time I launch my kite!Cultural SignificanceBeyond just being fun, kites hold deep cultural meaning in China. Traditional designs often feature images of mythical creatures like dragons or phoenixes that are symbols of good luck and prosperity. Kite flying festivals where teams perform choreographed routines with their kites are major events celebrated across the country.For me, flying a kite connects me to this rich cultural heritage. It's a way to take part in an ancient tradition while making new memories with my family. There's a sense of pride in mastering this iconic pastime.My Kite Flying AdventuresSome of my most joyful times have been spent flying kites at the park near my home. I remember the first kite my grandpa helped me build out of tissue paper and bamboo when I was little. After many failed attempts, we finally got it airborne and I was overjoyed watching it dance in the wind.Nowadays, I have a few different kites I enjoy flying - a classic flat kite, a box kite, and even a large delta kite that can reach incredible heights on gusty days. Each one presents its own challenges to control, but that's part of the fun. I love tinkering with the designs and bridles to optimize their performance.One particularly memorable kite flying day was during Spring Festival a couple years ago. The skies were filled with kites of all shapes, colors, and sizes. People were laughing, snapping photos, and reveling in the joyous atmosphere. I'll never forget the sense of community and happiness that day.Kite Flying Going ForwardAs I get older, kite flying will always hold a special place in my heart and keep me connected to my roots. It combines creativity, science, and tradition into one joyful activity thatanyone can experience. Whether flying solo or at a festival with thousands of others, there's a undeniable magical feeling of happiness and freedom when a kite takes flight.I look forward to one day passing on this tradition to my own children or grandchildren. Perhaps I'll even design my own innovative kite that adds to the culture's rich history! No matter what, you can be sure I'll never stop looking to the skies and feeling that childlike sense of wonder when I see a kite dancing on the wind.篇2Kite Flying English Essay NotesHello classmates! Today I want to share my thoughts about the kite flying unit we just finished in our Chinese language textbook. I really enjoyed reading the stories and doing the activities about kites. Kites are so cool and fun to fly!First, let me tell you about the main story we read called "The Kite Warrior." It was an ancient Chinese folktale about a young boy named Zhang who was an expert at flying kites. One day a mean lord wanted Zhang to fly kites for him, but Zhang refused because the lord was cruel to the villagers. So the lord capturedZhang's mother and said he would free her only if Zhang flew kites for his amusement.Zhang had no choice but to agree. However, he was secretly planning a daring trick with his kite. During the kite flying exhibition for the lord, Zhang maneuvered his kite in amazing ways, doing flips and spins that amazed the crowd. Then, at just the right moment, Zhang made his kite dive straight at the lord! The razor-sharp kite string sliced through the ropes holding Zhang's mother captive, setting her free before the lord could react.The story celebrated Zhang's courage, cleverness with kites, and devotion to his mother. I thought it was an exciting tale that showed kites can be tools for freedom, not just toys. The folktale inspired me to do research on the history of kite flying for my notes.Kites originated in China over 2,500 years ago! Some of the earliest kites were made from wood and cloth, similar to today's kite designs. Kites spread across Asia and were used for measuring distances, military signaling, and religious ceremonies. Kite flying became a popular outdoor recreation activity and art form by the Tang Dynasty around 700 AD.Different kite shapes and styles developed in China, like flat kites, box kites, centipede kites with many sections, and intricate butterly kites with ravelled split bamboo frames. Other Asian countries adopted kite flying traditions too, incorporating their own cultural designs and flying techniques. Kites were seen as symbols of good luck and prosperity.When kites were introduced to the Western world in the13th century, they sparked new innovations. In 1752, Benjamin Franklin famously flew a kite in a thunderstorm to demonstrate the electrical nature of lightning. The aerodynamic principles of kites also inspired the invention of aircraft like airplanes, gliders, and hot air ballons.Today, kite flying is enjoyed worldwide as a fun hobby, competitive sport, and artistic display. People build kites in all sorts of imaginative shapes like animals, geometric patterns, or 3D sculptures. Massive kites over 100 feet long have been constructed. Some kite festivals attract millions of spectators to see thousands of kites filling the sky in a brilliant kaleidoscope of colors and designs.For our unit activities, I made three different kites to fly. My first kite was a simple flat diamond shape, which was easy to assemble and launch by running with the wind at my back. Idecorated the panels with marker drawings of animals. Getting the kite high in the air felt awesome and rewarding!Next I challenged myself by篇3Here are some notes for a 2000-word English essay on "Kite Flying" from a third-grade student's perspective, for the second unit of their Chinese language textbook:Title: The Joy of Kite FlyingIt was a sunny spring day and my class was so excited! We were going on a field trip to the park to fly kites for our language arts unit on the joys of spring. I couldn't wait to run around outside after being stuck in the classroom all winter.My best friend Lily and I talked about what color kites we wanted as we walked to the park. I hoped I could get a really cool dragon kite! When we arrived, our teacher Mr. Wang helped us pick kites from a huge stack of different designs. I ended up with an awesome red kite that looked like a bird. Lily got a pretty blue butterfly kite.Next, we had to learn how to properly launch our kites. Mr. Wang showed us the techniques for getting them up in the air byrunning and letting out string at just the right moments. It was trickier than I thought! I couldn't get my kite up at first and felt frustrated.Lily's kite soared right up and she cheered. "Don't give up Mark! Keep trying!" she encouraged me. I took a deep breath and tried running faster while carefully letting out the string. Yes! My crimson bird kite finally caught the wind and climbed higher and higher into the sky. What an amazing feeling!For the next hour, the entire class joyfully ran around the fields getting our kites to perform all kinds of aerial acrobatics. We laughed whenever two kites crashed into each other after getting their strings tangled. It reminded me of birds playfully chasing one another.Lily and I had a contest to see whose kite could go highest. Her butterfly was gracefully floating at the end of its long string. But with one mighty pull, I managed to get my bird to rapidly ascend until it was just a speck in the clouds! "Yes, I'm the winner!" I shouted triumphantly.Too soon, Mr. Wang blew his whistle signaling it was time to bring our kites down. I carefully reeled mine in, not wanting this excellent adventure to end. As I admired the kite's bright colors and patterns, I felt so proud that I had mastered flying it.On the walk back to school, I thought about how amazing it was that a simple toy made of paper and sticks could soar so high just by catching the wind. Kite flying was much harder than I expected, but also more fun and rewarding once I got the hang of it. It combined sports, art, and a bit of science all in one activity.In class the next day, we wrote poems and stories inspired by our experiences at the park. I used lots of vivid adjectives to describe the sights, sounds, and feelings of getting my bird kite to take flight. I couldn't wait to build and decorate my own kite to fly again. Kite flying was definitely my new favorite spring hobby!。

描写直升飞机外形的英语作文From afar, the helicopter resembles a majestic dragonfly hovering gracefully amidst the boundless expanse of the sky, its streamlined silhouette cutting a sleek profile against the azure canvas. Its primary fuselage, akin to the dragonfly's elongated abdomen, forms thecentral axis around which all other components revolve.Extending outwards from the fuselage on either side are the stub wings, whose airfoil design provides the necessary lift to keep the aircraft airborne. These wings are meticulously crafted with a complex curvature that varies along their length, ensuring optimal airflow and minimizing drag. At the wingtips, small winglets act as miniature rudders, enhancing stability and control, especially during turns and maneuvers.The helicopter's most distinctive feature is its rotor system, which provides both lift and propulsion. The main rotor, positioned atop the fuselage, consists of multipleblades that rotate rapidly, creating a powerful downwash of air. This downwash, directed downwards by the aerodynamic shape of the blades, generates the lift that keeps the helicopter aloft.The blades of the main rotor are marvels of engineering, meticulously designed with a unique airfoil profile that optimizes airflow and minimizes noise. They are typically made of lightweight composite materials, ensuring both strength and agility. The blades are attached to a central hub, which is connected to the helicopter's engine througha complex system of gears and shafts.In addition to the main rotor, many helicopters also feature a tail rotor, which is positioned at the rear ofthe fuselage. The tail rotor counteracts the torque generated by the main rotor, preventing the helicopter from spinning uncontrollably. It also provides directional control, enabling the pilot to steer the aircraft byvarying the thrust of the tail rotor blades.The helicopter's cockpit, nestled within the forwardsection of the fuselage, provides a panoramic view for the pilot and co-pilot. Large windows afford excellent visibility, crucial for precision maneuvers and situational awareness. The cockpit is equipped with an array of instruments, controls, and navigation systems, allowing the pilots to monitor the aircraft's performance, communicate with air traffic control, and navigate through complex airspace.Beneath the fuselage, the helicopter's landing gear provides stability and support during takeoff, landing, and taxiing. The landing gear typically consists of retractable wheels or skids, depending on the specific design of the helicopter. Retractable wheels offer reduced drag during flight, while skids are more suitable for rough terrain or water landings.The helicopter's exterior is often adorned with various antennas, sensors, and other equipment, each fulfilling a specific role. These may include communication antennas for maintaining contact with air traffic control and ground crews, navigation aids for precise positioning, andsearchlights for nighttime operations. The specific configuration of equipment varies depending on the intended role of the helicopter, whether it is used for civilian, military, or emergency response purposes.In conclusion, the helicopter's intricate design is a symphony of engineering marvels, each component working in harmony to enable this remarkable aircraft to defy gravity and navigate the skies with precision and efficiency. From its aerodynamic fuselage to its sophisticated rotor system and advanced cockpit, the helicopter stands as a testament to human ingenuity and the relentless pursuit of innovation in aviation.。

关于蜻蜓和直升机的英语作文The Elegance of Dragonflies and the Ingenuity of Helicopters.In the vast and intricate web of nature, the dragonfly stands out as a remarkable creation, a testament to the wonders of evolution. Its elegant form, graceful flight, and adaptability to diverse environments have fascinated humans for centuries. Similarly, the helicopter, a product of human ingenuity and technological advancement, embodies the essence of innovation and problem-solving. While the dragonfly and the helicopter may seem worlds apart at first glance, a closer examination reveals striking parallels between them.The dragonfly, with its slender body and wide, transparent wings, is a natural aerial acrobat. Its flight is effortless and effortful at the same time, a dance of precision and balance in the air. The dragonfly's ability to hover, move forwards, backwards, and even sideways withease is remarkable. This flexibility and adaptability in flight are a result of its unique anatomical structure and the precise way its wings interact with the air.The helicopter, on the other hand, is the epitome of human engineering prowess. It mimics the dragonfly's aerial acrobatics with its rotors spinning at high speeds,creating lift and thrust that allow it to hover, ascend, descend, and move in any direction. The helicopter's design, which has undergone centuries of research and refinement,is a testament to the human capacity for innovation and problem-solving.Both the dragonfly and the helicopter exhibit a remarkable stability in flight. The dragonfly achieves this through its aerodynamic body and wing structure, whichallow it to respond quickly and accurately to changes in wind direction and speed. The helicopter, on the other hand, relies on a complex system of gyroscopes and servomechanisms to maintain stability, adjusting itsrotors' speed and pitch to counteract external forces.In addition to their shared flight characteristics, the dragonfly and the helicopter also exhibit remarkable adaptability to their environments. Dragonflies haveevolved to thrive in a wide range of habitats, fromwetlands and marshes to deserts and even urban areas. Similarly, helicopters have found applications in a diverse range of scenarios, from military operations and disaster relief to passenger transportation and recreational flying.The parallels between the dragonfly and the helicopter extend further to their respective roles in theirrespective ecosystems. Dragonflies are important predators, helping to control the population of small insects andflies. Their presence in an ecosystem is often indicativeof a healthy and well-balanced environment. Similarly, helicopters play a crucial role in various human activities, from search and rescue operations to construction and logging. They are a vital tool in disaster relief efforts, where they can reach areas inaccessible by other means, delivering supplies and evacuating victims.In conclusion, the dragonfly and the helicopter, whileseemingly unrelated at first glance, share a remarkable number of parallels in their structure, flight characteristics, and adaptability. Both embody the essence of their respective domains: the dragonfly as a testament to the wonders of nature and the helicopter as a symbol of human ingenuity and technological advancement. Their existence reminds us of the beauty and complexity of the natural world and the limitless possibilities of human creativity and innovation.。

第16卷　第3期流体力学实验与测量Vol.16No.3 2002年09月Experiments and Measurements in Fluid Mechanics Sep.,2002　文章编号:1007-3124(2002)03-0001-07战斗机机翼摇滚特性研究孙海生,姜裕标(中国空气动力研究与发展中心,四川绵阳621000)摘要:为了研究战斗机的机翼摇滚特性,运用风洞试验和数值模拟手段,对一典型三角翼布局开展了研究工作。

风洞试验研究探讨了不同攻角和初始角位移等因素对机翼摇滚特性的影响;运用非定常建模技术建立了机翼摇滚过程中的滚转力矩系数的表达式并进行了机翼摇滚的数值模拟,预测了发生机翼摇滚的临界攻角和轴承阻尼系数对摇滚特性的影响。

最后对机翼摇滚的发展、稳定阶段的能量转换进行了讨论。

研究结果表明机翼摇滚的数值模拟与试验结果具有较好的一致性。

关键词:大攻角;机翼摇滚;风洞试验;数值模拟中图分类号:V211.74+.1 文献标识码:AInvestigation on wing rock characteristicsfor a fighter configurationSUN Hai-sheng,JIANG YU-biao(China Aerodynamics Research&Development Center,Mianyang621000,China)A bstract:In order to study the wing rock characteristics of a fighter,the wing r ock c haracteristics for a fighter with delta wing c onfiguration is investigated in this paper.The experimental researc h about the effects of angle of attack and initial r oll angle on wing r ock characteristics are conducted in 4m×3m low speed wind tunnel.On the other hand,the critical angle of attack and the effect of different friction of ball bearing on wing rock were predicted by using numerical simulation based on the unsteady rolling moment modeling.In addition,the energy exchange during the developing and steady period of wing rock is also discussed.The results indicate that the numerical simulation is in good agreement with the experiment.Key words:high angle of attack;wing rock;wind tunnel test;numerical simulation0　引　言 机翼摇滚现象是飞行器在大攻角下由气动力作用激发的滚摆现象。

第二十六届（2010）全国直升机年会论文共轴双旋翼自转气动特性风洞试验方案及模型设计研究姬乐强，朱清华，李建波（南京航空航天大学直升机旋翼动力学重点实验室，南京210016）摘要：双旋翼自转性能是共轴式直升机安全性设计的重要指标，为从理论和试验两个方面对共轴双旋翼直升机自转状态进行分析研究，本文开展了共轴双旋翼自转气动特性风洞试验研究及其模型设计。

通过研究分析双旋翼自转气动特性风洞试验的特点和要求，设计了一套可确定旋翼总距、后倒角、风速以及上、下旋翼的间距等参数对自转状态的影响并能获得两副旋翼之间气动干扰特性的合理可行的试验方案，通过理论分析计算，设计完成了满足试验方案要求的试验模型，并通过有限元计算校核，该模型切实有效。

关键词：共轴式双旋翼；自转；试验方案；试验模型；风洞试验1引言自转着陆是旋翼类飞行器所特有的降落方式，它能保证旋翼飞行器飞行中发动机或传动系统失效时仍能安全着陆，能提高其安全性和生存力，是旋翼类飞行器设计当中的一个重要内容和性能指标。

目前，共轴式直升机应用已经十分广泛,当直升机因意外导致旋翼驱转动力失效时，共轴式直升机应该具有自转飞行和自转着陆的能力。

然而，关于共轴式双旋翼自转状态的气动特性研究，特别是自转的两副旋翼之间的相互气动干扰问题的研究在国内外的相关文献中未见报道。

这就需要从理论和试验两个方面对共轴式直升机自转状态的气动特性进行深入的研究。

为了探知共轴双旋翼直升机自转状态时的气动特性，需进行共轴双旋翼自转气动特性风洞试验。

本文针对共轴式自转双旋翼的试验要求，对试验方案及试验模型进行了设计研究，最终，明确了设计参数，设计了有效的试验模型，以及提出了切实可行的试验方案，本课题将有利于共轴式双旋翼飞行器的安全性设计。

2试验方案设计2.1设计要求本试验主要利用南京航空航天大学直升机旋翼动力学国家级重点实验室风洞，以及风洞试验室已具备的试验条件，进行共轴双旋翼自转气动特性风洞吹风试验。

仿写蜻蜓外形作文标题：蜻蜓之美：细腻而独特的形态The dragonfly, a graceful insect, captivates us with its unique and intricate appearance. 蜻蜓，这种优雅的昆虫，以其独特且精细的外貌吸引着我们。

With a slender body and elongated wings, the dragonfly exudes elegance and dynamism. 它拥有纤细的身躯和修长的翅膀，散发出优雅与活力的气息。

Its eyes, composed of thousands of lenses, offer a panoramic view of its surroundings. 它的眼睛由成千上万个透镜组成，为它提供了周围环境的全景视野。

The intricate patterns on its wings, like nature's artwork, are both beautiful and functional, aiding in flight. 翅膀上精细的图案，宛如大自然的艺术品，既美丽又实用，有助于飞行。

The delicate veil of its wings, transparent and iridescent, shimmers in the sun, a sight to behold. 翅膀上那层纤细的薄膜，透明而虹彩闪烁，在阳光下熠熠生辉，令人叹为观止。

The dragonfly's tail, slender and pointed, adds to its aerodynamic elegance, making it a master of the skies. 蜻蜓的尾巴，纤细而尖锐，为其增添了空气动力学的优雅，使其成为空中的主宰。

Its coloration, ranging from muted greens to vibrant blues, reflects the diversity of nature's palette. 它的色彩从柔和的绿色到鲜艳的蓝色不等，反映了大自然色彩的多样性。

褶皱结构对蜻蜓后翅的气动特性影响分析罗云;何国毅;王琦;宋航;陈冬慧【摘要】褶皱结构是否能对蜻蜓后翅气动性能产生正面的影响,对蜻蜓后翅气动性能的影响是否与雷诺数(Re)相关.建立接近真实蜻蜓后翅的三维蜻蜓后翅褶皱模型和拥有同样外形的三维平板模型,利用计算流体力学方法分别计算两个模型在不同Re、不同攻角(α)下滑翔飞行时的气动特性.结果表明:褶皱结构的存在会明显提高蜻蜓后翅的升力,但是同时也会增大其阻力;不同Re情况下,褶皱结构对蜻蜒后翅气动性能的影响不同,当Re=1 000,α=0°～25°时,蜻蜒后翅的气动效能始终略优于三维平板;褶皱结构对蜻蜓后翅气动特性的影响与α也相关,α较大时蜻蜓后翅的气动效能略优于三维平板.【期刊名称】《航空工程进展》【年(卷),期】2019(010)003【总页数】8页(P355-362)【关键词】蜻蜓后翅;雷诺数;滑翔;褶皱结构;计算流体力学【作者】罗云;何国毅;王琦;宋航;陈冬慧【作者单位】南昌航空大学飞行器工程学院,南昌330063;南昌航空大学飞行器工程学院,南昌330063;南昌航空大学飞行器工程学院,南昌330063;南昌航空大学飞行器工程学院,南昌330063;南昌航空大学飞行器工程学院,南昌330063【正文语种】中文【中图分类】V211.30 引言蜻蜓堪称有翼昆虫界的战斗机，具有优异的飞行本领，是微型扑翼飞行器最合适的仿生对象。

蜻蜓通过振动翅膀，产生不同于周围大气的局部不稳定气流，利用气流产生的涡流上升，能在很小的推力下翱翔[1]，甚至可以在几乎不消耗能量的情况下滑翔很长一段距离。

蜻蜓高超的飞行能力更体现在它不但可以向前、后、左、右各个方向飞行，还可以进行急转、俯冲、空中悬停等高难度动作，甚至能够短距离上下垂直飞行[2]。

蜻蜓飞行常表现为拍动、滑翔和悬停等姿态，尤其是在炎热天气时，滑翔飞行更是蜻蜓最常采用的飞行方式。

滑翔飞行不仅可以降低翅膀的扑动频率，减少能量消耗，还可以利用空气对流等方法进行体温调节[3]。

国之重器鲲龙英文介绍The Kunlong, a national heavyweight, is a remarkable aircraft that represents the pinnacle of China's aviation technology. It is a unique and innovative aircraft designed to fulfill a wide range of mission requirements, from maritime rescue operations to forest firefighting.The Kunlong boasts an impressive array of features that set it apart from other aircraft. Its design incorporates advanced aerodynamic principles, resulting in exceptional flight performance and stability. The aircraft is capable of operating in a variety of environments, from calm seas to turbulent skies, making it a versatile tool for various missions.One of the Kunlong's most noteworthy capabilities is its ability to perform maritime rescue operations. With its large cargo hold and advanced life-saving equipment, the aircraft can quickly deploy rescue teams and supplies to stranded vessels or individuals in distress. This capability is crucial in saving lives and minimizing the impact of maritime disasters.In addition to maritime rescue, the Kunlong is also effective in fighting forest fires. Its ability to carry large volumes of water and retardant allows it to quickly suppressfires and contain their spread. This feature makes the Kunlong an invaluable asset in protecting vulnerable forest ecosystems from the devastating effects of wildfires.The Kunlong's development represents a significant milestone in China's aviation industry. It demonstrates the country's progress in aircraft design and manufacturing, as well as its commitment to enhancing national security and emergency response capabilities. With its unique capabilities and versatility, the Kunlong is poised to become a vital asset in China's arsenal of national heavyweights.。