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大学英语课堂师生交互中的反馈与回应调查与分析本研究采用对五堂大学英语课堂进行录音的方式，以课堂实录转写成的文字材料为语料，对课堂中师生交互时出现的反馈( feedback )与回应( uptake ) 进行了统计分析。
结果表明：（1 ）五位教师的课堂中共出现六种反馈形式，其中重构的出现频率最高（41.4 %)。
(2) 最成功的反馈形式是直接纠错，它产生了93.7%的学生回应；最不成功的为重构，只产生39.5%的学生回应。
（3）直接纠错产生最多的语法纠错；重构产生最多的词汇纠错。
语音纠错则均匀地分布在五种反馈中，只有引出这一反馈形式没有产生任何语音纠错。
标签：交互；反馈；回应；纠错导言a. 研究目的本研究的目的是调查与分析大学英语课堂师生交互中的反馈(feedback )与回应(uptake 情况。
为此，我们整理了涉及到5位教师和大约200名学生的5节大学英语课堂的录音稿（共1.5小时）。
分析了其中的错误(error)，反馈和回应。
本节开始回顾对反馈与回应的研究的有关文献，然后以介绍本研究的说明而结束。
b. 文献回顾近十年来对外语课堂反馈与回应的研究在国外已取得不少成果。
首先，Lyster 和Ranta(1997) 研究了小学浸泡式法语课堂。
他们的结果表明，虽然最常见的反馈形式是重构(recast), 占到所有反馈形式的55%，重构却只能产生最少的学生回应(31% )和学生纠错(repair)(18%)。
相反，引出（elicitation)这一反馈形式却能产生更多的学生纠错（45%）。
其次，Ellis et al(2001)和Panova和Lyster（2002）两个对ESL课堂的描述性研究得出了几乎彼此相矛盾的结论。
Ellis et al的研究结果是重构明显多于其它反馈形式，且产生了最多的学生回应（75 %）。
他们认为之所以结论与Lyster 和Ranta的结论不同可能是因为学生在以交际为主的课堂中更关注语法形式，也可能是因为在学生上课之前教师向他们灌注了过多的语法形式。
年青一代的影响大学英语作文如下：Title: The Indelible Imprint: How the Younger Generation Shapes Higher EducationIn an era where the narrative of progress and innovation is often led by the youth, the impact of the younger generation on higher education stands as a testament to their influential strides. A microcosm of emerging trends, universities worldwide are experiencing a transformative wave, propelled by the dynamic energies and fresh perspectives of the new generation. This essay endeavors to dissect the multifaceted influence that young adults exert on colleges and universities, an influence that is both revealing and pivotal for the future of educational institutions.The digital natives, often referred to as Generation Z, bring with them a fluency in technology that has redefined the learning landscape. Reared in the age of smartphones and the internet, they have seamlessly integrated digital tools into their academic endeavors. Online collaboration platforms, virtual reality simulations, and even artificial intelligence tutors now supplement traditional teaching methods, enriching the educational experience. Their ease with digitization has nudged universities to embrace tech-enabled education, ensuring a preparedness for a technologically advanced world.Moreover, the younger generation's penchant for entrepreneurship and innovation has cultivated a culture of startups and ideas within university precincts. Incubators and accelerators programmed by colleges not only support but also foster budding entrepreneurs. Courses and seminars focusing on creativity, critical thinking, and leadership skills are increasingly prevalent, all geared towards empowering students to not just consume knowledge but to generate it.Social consciousness and advocacy, values held dear by today's youth, have also found their way into the fabric of higher education. Universities are no longer just about personal growth but are seen as arenas for societal change. Courses on sustainability, social justice, and global citizenship are reflective of a student body that does not wish to confine learning within classroom walls. Service learning programs and volunteer opportunities have become integral parts of the academic curriculum,preparing students for active roles in community betterment and global issues.Additionally, there is a noticeable shift towards mental health awareness within campuses, prompted by the declining psychological well-being among students. Universities are now more proactive in providing counseling services, workshops on stress management, and campaigns against stigmatization of mental illnesses. The younger generation's demand for holistic health and well-being has driven institutions to prioritize student welfare, recognizing the inextricable link between emotional stability and academic success.However, this influence is not without its challenges. There is an ongoing debate on the financial implications of higher education, with significant student debt and rising tuition fees casting shadows on the learning experience. Students are advocating for more affordable education and transparent fee structures, pushing universities to confront budgeting concerns and explore innovative funding models.In conclusion, the imprint of the younger generation on higher education is profound and far-reaching—a force that compels evolution and reflects the values and visions of a society in transition. As we navigate the contours of this changing landscape, it is imperative for educational institutions to continue engaging with the vibrant minds of the young, not merely as students but as agents of change. For the vibrancy they infuse into these ancient halls of learning is not just a phase but a permanent transformation, one that ensures the relevance and vitality of higher education for generations to come.。
2014英语专四作文2014年英语专业四级作文题目，The Influence of Internet。
参考范文：The Influence of Internet。
With the rapid development of science and technology,the Internet has become an indispensable part of our daily life. It has brought about significant changes in various aspects of our society, such as communication, education, and entertainment. In this essay, I will discuss the influence of the Internet on our lives.First of all, the Internet has greatly facilitated communication. People can now easily keep in touch with friends and family through social media platforms, such as Facebook and Twitter. In addition, the Internet has also made it possible for people to communicate with others from different parts of the world through email, video calls,and instant messaging. This has not only brought people closer together but has also made the world a smaller place.Secondly, the Internet has revolutionized the way we access information and knowledge. In the past, people hadto rely on books and newspapers for information, but now they can simply go online and find whatever they need. This has made it much easier for students to do research fortheir studies and for professionals to stay updated withthe latest developments in their fields.Furthermore, the Internet has changed the way we entertain ourselves. With the rise of streaming services, such as Netflix and YouTube, people can now watch movies,TV shows, and videos on demand. This has made it possiblefor people to enjoy their favorite entertainment whenever and wherever they want.However, the Internet also has its downsides. One ofthe major concerns is the issue of privacy and security. With the increasing amount of personal information being shared online, there is a risk of this information beingexploited by malicious individuals. In addition, the Internet has also given rise to cyberbullying and online harassment, which can have serious consequences for the victims.In conclusion, the Internet has had a profound impact on our lives, bringing both positive and negative changes. It has revolutionized the way we communicate, access information, and entertain ourselves. However, it also poses challenges in terms of privacy and security. Therefore, it is important for us to use the Internet responsibly and be aware of its potential risks. Only in this way can we fully benefit from the advantages of the Internet while minimizing its negative impact.。
2011年4级英语作文2011年四级英语作文题目，The Influence of Internet。
参考范文：The Influence of Internet。
With the rapid development of technology, the Internet has become an indispensable part of our daily life. It has greatly changed the way we live, work and communicate. Itis true that the Internet brings us a lot of convenience, but it also has some negative effects on our lives.Firstly, the Internet has made it much easier for people to communicate with each other. We can send emails, make video calls and chat online with people from all over the world. This has greatly improved our ability to connect with others and has made the world a smaller place. Secondly, the Internet has also made it easier for us to access information. We can search for anything we want toknow and find the answer within seconds. This has greatly improved our ability to learn and has made it easier for us to stay informed about the world around us.However, the Internet also has some negative effects on our lives. Firstly, the Internet has made it easier for people to become addicted to it. Many people spend hours every day on the Internet, which can have a negative impact on their health and well-being. Secondly, the Internet has also made it easier for people to access inappropriate content. There is a lot of harmful and offensive material on the Internet, and it is very easy for people, especially young people, to come across it.In conclusion, the Internet has had a significant impact on our lives. It has brought us a lot of convenience and has greatly improved our ability to communicate and access information. However, it also has some negative effects, and it is important for us to be aware of them and to use the Internet responsibly.仿写：The Impact of Social Media。
描绘网红对青少年的影响英语作文English:The influence of internet celebrities, also known as "wanghong" in China, on teenagers has been a topic of debate in recent years. These internet celebrities often have a large following on social media platforms and are seen as role models by many young people. While some argue that wanghong can inspire teenagers to pursue their dreams and passions, others believe that they can promote unhealthy beauty standards and materialism. Many young people are easily influenced by the lifestyle and products endorsed by these internet celebrities, leading to a rise in consumerism and social comparison. Additionally, the constant exposure to carefully curated images and videos on social media can negatively impact teenagers' self-esteem and mental health. It is important for parents and educators to help young people critically evaluate the messages and values promoted by internet celebrities, and to encourage them to develop their own identities and values.Translated content:近年来，互联网红人（在中国被称为“网红”）对青少年的影响成为了一个备受争议的话题。
孔子对我们的影响英语作文The Influence of Confucius on Our LivesConfucius, the ancient Chinese philosopher, has had a profound impact on our lives. His teachings have shaped not only Chinese culture but also the world's understanding of ethics and morality.One of the most significant influences of Confucius is his emphasis on education. He believed that education should be accessible to all, regardless of social status or wealth. This philosophy has influenced modern-day educational systems, where equality in education is a fundamental right.Another important aspect of Confucianism is the concept of "ren," which translates to benevolence or humaneness. Confucius believed that individuals should treat others with kindness and respect, fostering harmonious relationships. This principle has been adopted in many aspects of our lives, from interpersonal relationships to business ethics.Furthermore, Confucius advocated for the importance of self-cultivation and personal development. He believed that individuals should strive to improve themselves continually, both intellectually and morally. This philosophy has influenced our modern pursuit of self-improvement and lifelong learning.In conclusion, Confucius's teachings have had a lasting impact on our lives. His emphasis on education, benevolence, and self-cultivation continue to shape our values and guide our behavior. As we navigate the complexities of the modern world, the wisdom of Confucius remains relevant and influential.。
某个人对自己的影响作文600字英文回答：The influence of oneself can be profound and far-reaching. It shapes our thoughts, actions, and ultimately determines the path we choose in life. Personally, I believe that the influence I have on myself is significant and has played a crucial role in shaping my character and achievements.First and foremost, self-influence is reflected in the way we think. Our thoughts are like seeds that grow into actions and behaviors. By cultivating positive thoughts and focusing on personal growth, I have been able to overcome challenges and achieve my goals. For instance, when faced with a difficult task or setback, I remind myself of my capabilities and the potential for success. This positive self-talk helps me stay motivated and determined to overcome obstacles.Furthermore, self-influence extends to our actions and behaviors. The choices we make on a daily basis are a reflection of our values and beliefs. By setting high standards for myself and holding myself accountable, I have been able to develop discipline and perseverance. For example, I have a strict study routine that I follow diligently, which has helped me excel academically. Additionally, I make it a point to engage in regular exercise and maintain a healthy lifestyle, which has positively impacted both my physical and mental well-being.Moreover, self-influence is also evident in the relationships we cultivate. The way we interact with others is a reflection of our own self-worth and values. By practicing empathy, kindness, and respect towards others, I have been able to build strong and meaningful connections. These relationships have provided me with support, guidance, and opportunities for personal growth.In conclusion, the influence I have on myself is immense and has shaped my thoughts, actions, and relationships. By cultivating positive thoughts, makingconscious choices, and nurturing meaningful connections, I have been able to achieve personal growth and success.中文回答：自己对自己的影响是深远而重要的。
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化工进展Chemical Industry and Engineering Progress2021年第40卷第12期新型双压Linde-Hampson 氢液化工艺设计与分析曹学文，杨健，边江，刘杨，郭丹，李琦瑰（中国石油大学(华东)山东省油气储运安全重点实验室，山东青岛266580）摘要：为降低氢液化厂的生产能耗与投资成本，加快我国氢能商业化、民用化的发展，本文提出了一种采用液化天然气（LNG ）预冷的新型双压Linde-Hampson （L-H ）氢液化工艺系统。
系统的设计液氢产量为5t/d ，采用膨胀降温与换热冷却相结合的方法实现了对氢气的深冷。
借助Aspen HYSYS 软件对工艺流程展开了详细的模拟计算与分析，结果表明，该氢液化系统的比能耗为9.802kWh/kg H 2，㶲效率为41.4%，系统的总㶲损失为1373.3kW ，其中换热设备的㶲损失占主要部分；在对系统中关键参数进行的灵敏度分析中发现，氢气预压缩压力在2~4MPa 范围内变化对液化系统的比能耗和氢气液化率影响较大，而LNG 的加压压力对系统性能影响较小。
新型氢液化工艺系统设备简单，投资成本较低，具备良好的液化性能，在未来中小型氢液化厂的建设中优势明显。
关键词：氢液化；HYSYS 软件；液化天然气预冷；㶲分析；灵敏度分析中图分类号：TK91文献标志码：A文章编号：1000-6613（2021）12-6663-07Design and analysis of a new type of dual-pressure Linde-Hampsonhydrogen liquefaction processCAO Xuewen ，YANG Jian ，BIAN Jiang ，LIU Yang ，GUO Dan ，LI Qigui(Shandong Key Laboratory of Oil &Gas Storage and Transportation Safety,China University of Petroleum (East China),Qingdao 266580,Shandong,China)Abstract:In order to reduce the production energy consumption and investment cost of hydrogen liquefaction plants and accelerate the development of hydrogen energy commercialization and civilian use in China,a novel dual-pressure Linde-Hampson (L-H)hydrogen liquefaction process using LNG pre-cooling is proposed.The designed liquid hydrogen output of the system is 5t/d and the method combining expansion and cooling with heat exchange is adopted to realize deep cooling of hydrogen.Aspen HYSYS software is used to carry out detailed simulation calculation and analysis for the process.The results show that the specific energy consumption and exergy efficiency of the hydrogen liquefaction process are 9.802kWh/kg H 2and 41.4%,respectively,and the total exergy loss of the process is 1373.3kW,of whichthe exergy loss of the heat exchange system accounts for the main part.It is found from the sensitivity analysis of the key parameters in the process that the change of the pre-compression pressure of the hydrogen in the range of 2—4MPa has a greater impact on the specific energy consumption and hydrogen liquefaction rate of the liquefaction process,while the pressure of LNG has little impact on the system.The novel hydrogen liquefaction process has simple equipment,low investment cost,and better研究开发DOI ：10.16085/j.issn.1000-6613.2021-0060收稿日期：2021-01-11；修改稿日期：2021-03-15。
left a big influence on sth -回复题目：中括号内的内容对某事物产生了重大影响引言：在我们的生活中，总会存在一些特定的事物或者人物，对于某些领域或者行业产生了非常重要的影响。
本文将会深入探讨中括号内所指代的内容是如何通过一系列步骤，对某事物产生了巨大的影响。
第一步：认识和了解首先，要对中括号内所指代的内容进行认识和了解。
这可能包括对历史背景、相关文献的阅读、专家采访以及对相关人物或事件的调查研究等等。
只有当我们对一件事物或人物有全面的认识和了解时，才能够深入探讨其对某事物的影响。
第二步：分析和评估接下来，我们需要通过对中括号内所指代的内容进行分析和评估，以确定其对某事物的影响程度。
在这一步骤中，可以采用专家分析、数据统计、实地考察等方法，从多个角度综合分析和评估其影响。
同时，也需要考虑中括号内所指代的内容对该事物的正面和负面影响。
第三步：寻找共性和关联性在确认中括号内所指代的内容对某事物确实产生了重大影响之后，我们需要进一步寻找其中的共性和关联性。
这可能包括与其他相关人物或事件进行对比，分析其各自的影响，并寻找相互之间的相似之处。
通过寻找共性和关联性，我们可以更好地理解中括号内所指代的内容对于该事物的深远影响。
第四步：理论模型和实践应用理论模型和实践应用是我们进一步探索中括号内所指代的内容对某事物影响的关键步骤。
通过构建理论模型，我们可以更加深入地分析该内容对某事物的具体方式和机制；而实践应用则可以通过实际操作验证和证明该内容对某事物的有效性和实用性。
这一步骤是理论和实践相结合的过程，可以帮助我们更好地理解和利用中括号内所指代的内容。
第五步：推广和传播最后，为了使中括号内所指代的内容对某事物产生更广泛的影响，推广和传播是不可或缺的步骤。
这包括通过各种媒体平台、学术研讨会等宣传和分享该内容的重要性和价值。
通过推广和传播，我们可以使更多的人认识和了解中括号内所指代的内容，并在各自的领域中应用和发扬光大。
• SID 00 DIGEST 1000 41.4: Influence of Ion Transport in AFLCDsH. ZhangAlcatel Bell N.V., Francis Wellesplein 1, B-2018 Antwerp, BelgiumK. D’havé, H. PauwelsDept. of Electronics & Information Systems, Ghent University, St-Pietersnieuwstraat 41, B-9000 Gent, BelgiumD. D. Parghi, G. HeppkeAnisotropic Fluids Research Group, Iwan-N.-Stranski Institute of Physical & Theoretical Chemistry,Sekr. ER11, Technical University of Berlin, Str. des 17 Juni 135, D-10623 Berlin, GermanyAbstractIn this article we present measurement results of greylevel hysteresis in an AFLC mixture in test cells with different alignment layers at various temperatures. Ion content has also been measured in the AFLC mixture in order to study the relationship between ionic contamination and the image sticking phenomenon.1. IntroductionWithin recent years antiferroelectric liquid crystal displays (AFLCDs) have been investigated as an alternative to the conventional nematic liquid crystal displays (NLCDs). AFLCDs offer some advantages, including fast switching speeds, wide viewing angles, double hysteresis (which allows passive matrix addressing) and the possibility for analogue greyscale [1]. Nevertheless, there generally exists ionic contamination in almost all LCDs which influences electrooptical performance. The influence of ion transport in nematic and ferroelectric liquid crystals has been studied extensively [2,3,4], while the influence of ionic contamination in AFLCs has, however, not been considered to be of importance due principally to the symmetric addressing schemes used in devices and consequently has not been studied very much. Nevertheless, it was pointed out recently that as the temperature increases the transit time of ions (the time ions need to move from one side of the cell to the other) will be around the frame period [5,6]. This will lead to the separation of ions and consequently affect the electrooptical performance of an AFLCD. In this paper, in order to investigate the influence of ion transport on AFLC addressing, we present our grey level hysteresis measurement results of an AFLC mixture under a wide temperature range. These measurements have been carried out under various conditions to examine the influence of several factors, such as different types of alignment layers, the frame period and the number of repetition cycles etc. Ionic content in the corresponding test cells has also been measured to ascertain the relationship between the ion mobility, concentration, their temperature behaviour and the detected grey level hysteresis phenomenon .2. ExperimentalThe AFLC mixture used in this paper is pent6’, which is composed of chiral and racemic components. The phase transition temperatures and some physical properties of the mixture are listed in tables 1 and 2 and examples of components present in the mixture are shown in figure 1. The mixture possesses a reasonably wide-temperature SmC A * phase, amoderately high spontaneous polarisation, and a short response time at room temperature.Table 1. Phase transition temperatures of pent6’ (ºC, determined by microscopy and DSC).Recryst. SmC A * SmA* I •<25•72.8 • 94.6 •Table 2. Physical properties of the mixture at room temperature (5µm ITO-coated cell, anti-parallel buffedpolyimide).V th(V ac µm -1) Response time AFO – FO (τ, µs)Tilt angle (θ, °) Max P s (nCcm -2) 13.2 60 28.5 83.2C 12H 2536H 1736H 17C 12H C 10H 2136H 17C 12H 252CH 36H 17(S)(S)(S)Figure 1. Examples of SmC A * and SmC alt -forming materialspresent in the pent6’.3. Results and Discussions 3.1 Ionic ContaminationTransient current measurement has been applied to detect ionic contamination in the mixture [9, 10]. After short-circuiting the cell for a period of time, a series of voltage pulses is applied to the liquid crystal. By measuring the leakage current with a low-noise current-voltage amplifier, several ionic species can be detected. To characterize ionic contamination, both ion mobility µi and concentration n i are calculated [10]. We repeat the measurement at different temperatures (from 30 °C to above 100 °C). This not only improves the reliability of the results but also gives us more information about the ionic contamination in the liquid crystals. Figure 2 shows the measured ion mobility (figure 2a) and concentration (figure 2b) of different ion species as a function of reversed absolute temperature, using polyimide and nylon as alignment materials, respectively. From figure 2a, one sees that atISSN0000-0966X/00/3101-1000-$1.00+.00 © 2000 SIDSID 00 DIGEST • 100130 °C, the mobility of the fastest ion species is about 10-11 V.m/s². Under the holding voltage of about 10 V, as applied in this work, the transit time of these ions is around 25 ms. This is almost comparable to the frame period. Besides, as the temperature rises, the ion mobility increases rather fast and from 40 °C, the ion transit time becomes even smaller than the frame period, which leads to separation of ions at the end of the frame time. Figure 2b shows that the ion concentration is generally of the order of 1020 #/m³. Under this condition, if these ions are completely separated, the electric field generated by these ions is equivalent to an extra voltage of around 1 V. This ionic field will therefore influence the electrooptical performance of the LCDs.1.E-131.E-121.E-111.E-101.E-090.00250.00270.00290.00310.00330.00351/T (K -1)m o b i l i t y (V .m /s ²)(a)1E+191E+201E+211E+220.00250.00270.00290.00310.00330.00351/T (K -1)c o n c e n t r a t i o n (#/m ³)(b)Figure 2. Measured ion mobilities (a), and concentration (b), as a function of reversed absolute temperature in test cells filled with pent6’ and using Nylon6,6 and polyimide alignment materials. ('star' stands for polyimide and 'box' for nylonalignment layers.)3.2 Grey Level HysteresisIn order to study the influence of ion transport on the electrooptical performance of AFLCs and to test the above analysis, grey level hysteresis measurements have been carried out on a test sample with Nylon6,6 alignment layer and filled withpent6'. The test sample has a thickness of 1.6 µm and was placed in a programmable hot stage between crossed polarizers and was oriented in such a way that the optical transmission was symmetric on application of positive and negative voltage signals. The transmission was detected by a photodiode and the results were observed on an oscilloscope and then stored on a computer. A LabVIEW program was written to program the function generator and the oscilloscope so that the entire measurement process could be carried out automatically.Similar to the greylevel hysteresis measurement in an SSFLC, a ‘step up-step-down’ cycle was applied. This cycle began from the dark state: the AFLC was switched, via a few intermediate greylevels, to the bright state. After maintaining the AFLC in the bright state for a number of frames, it was switched gradually back to the dark state, again via various intermediate grey levels. The optical transmission of each state was measured by integrating the transmission throughout the whole frame. The measured transmission on application of identical voltage signals during different processes, i.e. when going from the bright to the dark state and vice versa were compared. In the ideal case, the optical transmission is expected to be always identical since identical voltages are applied. In practice, however, different optical responses were always detected which form a hysteresis. An example of the addressing signal and the optical transmission measured at 40 °C is given in figure 3 and the summarized grey level hysteresis is shown in figure 4. In order to avoid the influence of the assymetric optical response of AFLC to positive and negative voltages, all the transmission results presented here correspond to positive voltages. The experiments show that the results corresponding to negative voltages are similar.0.080.10.120.140.16time (s)Figure 3. Grey level hysteresis measurement results at 40 °C. The applied addressing signal contains a selection pulse of various amplitude, a holding voltage of 9.25 V, a well voltage of 18 V, 100 µs and a reset time of 3 ms. Different grey levels were obtained by varying the amplitude of the selection pulse from 23 V to 27 V. The frame period was 10 ms and each statewas repeated 20 frames .• SID 00 DIGEST1002 In order to characterize this phenomenon quantitatively, the image sticking value is defined asS average Tr Tr Tr Tr bright dark dark bright =−−→→()max minwhere Tr represents the optical transmission. This measurement was repeated with varying frame period from 10 ms to 40 ms and varying number of repetition cycles. The results are given infigure 5.Grey level hysteresis00.511.522.533.52324252627selection voltage (V)T r a n s m i s s i o n (a .u .)Figure 4. Different optical transmissions were detected when the same voltage was applied on going from bright to dark state and vice versa, thus forming a grey level hysteresis.From the experimental results, one can observe that generally a certain grey level becomes brighter or darker after having been kept in that state for a number of frames, which is similar to the situation found in an SSFLC. In SSFLCs, this is explained by charge separation and accumulation at the alignment layer interface under the depolarization field when the crosstalk voltage is applied to the pixel after the line time. In AFLCs, however, as the addressing voltage is always reversed after each frame, the liquid crystal is switched between two optically equivalent but physically different ferroelectric states, in which the depolarization field also reverses. Nevertheless, in contrast to the case in an SSFLC, the averaged driving voltage within each frame is not zero. Instead, a holding voltage of about 10 V is applied during most of the frame period. During the period in which this holding voltage is applied the positive and negative ions become separated. As analyzed previously, from about 40 °C, the transit time of the fast ions is of the order of the frame period. Consequently an ionic field in the opposite direction to that of the applied field is generated. The magnitude of this ionic field can be calculated from the ion concentration measured from the transient leakage current (figure 2b), taking the cell thickness into account. It is found to correspond to an extra voltage of around 1V. This ionic field influences not only the amplitude of the selection pulse, which eventually determines the grey level to be displayed, but also the reset process at the end of each frame, which plays an important role in the reproducibility of the transmission [7]. In comparison with the case in SSFLCs under symmetrical addressing conditions, the image sticking in an AFLC occurs to a much smaller extent. This indicates that AFLCs are less sensitive to ionic influences. Similar to the case of SSFLCs, sometimes, negative image sticking values have been obtained. This is mainly due to the symmetric addressing scheme in which the trapping effect of ions on the surface of the alignment layer becomes non-negligible [8]. Depending on the trapping and release velocity, the ionic field generated by the trapped ions can be either positive or negative, i.e. either in the same or opposite direction of the applied voltage. Increasing the frame period or the number of repetition cycles leads to an increase in image sticking. This is quite logical as ions have more time to separate and to be trapped at the alignment layers.-0.00200.0020.0040.0060.0080.01frame period (ms)i m a g e s t i c k i n g(a)-0.01-0.00500.0050.01number of repetition cyclesi m a g e s t i c k i n g(b)Figure 5. Image sticking at various frame periods (a) and atvarious number of repetition cycles (b).SID 00 DIGEST • 1003This measurement was repeated at different temperatures within the range of the SmC A * phase. The measured image sticking is presented in figure 6. Apparently, image sticking increases as the temperature rises. This is expected as both the ion mobility and the concentration increases with increasing temperature. As a result, the generated ionic field also becomes higher.Nylon 6,6-0.0200.020.040.060.080.10.120.14temperature (°C)i m a g e s t i c k i n gFigure 6. Image sticking measured at different temperaturesusing test cells with Nylon6,6 as alignment layer.The same experiment was repeated on a test cell filled with the same AFLC mixture pent6' but with polyimide as alignment layer. The thickness of the sample is 1.44 µm and the image sticking values at various temperatures are summarized in figure 7.Polyimide-0.0500.050.10.150.20.250.30.35temperature (°C)i m a g e s t i c k i n gFigure 7. Image sticking measured at different temperaturesusing test cells with polyimide as alignment layer.Similar results were obtained. The only exception occurs at 60 °C. It follows that as far as the image sticking alone is concerned, Nylon6,6 alignment layer is preferable to this polyimide.4. ConclusionsThe above grey level image sticking experiments confirm the analysis, from the ion content measurement, that ions areseparated to some extent and even trapped at the alignment layer interface after one frame. This consequently generates an ionic field and as a result, the selection pulse amplitude and the reset process are affected, which gives rise to a shift in optical transmission. This phenomenon increases with increasing temperature. Realizing that symmetric addressing approaches cannot completely avoid ion transport influence in LCDs, for real display applications not only the AFLC mixtures should be further purified but also both addressing technique and cell construction should be optimized in order to minimize this ionic influence.5. AcknowledgementsThis work has been carried out in the framework of the European Network program ‘ORCHIS’.6. 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