共查询到20条相似文献，搜索用时 640 毫秒
1.
Teachers and students play important roles in teaching activity,and they are the most essential parts of the system.The relationship between teachers and students,the core schooling interpersonal relationship,directly determines whether the teach ing activities can go smoothly or not,and is an important index to measure the quality of teachers and students’school life,and also is an important factor that affects the social function of education.For a long time,relationship between teachers and students has been a hot topic in education and in different sectors of the society.This dissertation aims at discussing the teacher-student role changing in interactive teaching mode to provide reference for building a harmonious relationship between teachers and stu dents. 相似文献
2.
Probability density function (PDF) method is proposed for analysing the structure of the reconstructed attractor in computing the correlation dimensions of RR intervals of ten normal old men. PDF contains important information about the spatial distribution of the phase points in the reconstructed attractor. To the best of our knowledge, it is the first time that the PDF method is put forward for the analysis of the reconstructed attractor structure. Numerical simulations demonstrate that the cardiac systems of healthy old men are about 6 - 6.5 dimensional complex dynamical systems. It is found that PDF is not symmetrically distributed when time delay is small, while PDF satisfies Gaussian distribution when time delay is big enough. A cluster effect mechanism is presented to explain this phenomenon. By studying the shape of PDFs, that the roles played by time delay are more important than embedding dimension in the reconstruction is clearly indicated. Results have demonstrated that the PDF method represents a promising numerical approach for the observation of the reconstructed attractor structure and may provide more information and new diagnostic potential of the analyzed cardiac system. 相似文献
3.
For a repairable redundant system consisting of two same components with exponential lifetime and general repair time distribution,the probability densities of the system in some state at time t were determined by a group of ordinary and partial differential equations,called density evolution equations.It was proved that the time-dependent solution of the density evolution equations uniquely exists and strongly converges to its steady state density solution by a semi-group method.In this proof,it is not necessary to suppose that the repair rate function is bounded.The technique of the proof is valuable for many density evolution equatons. 相似文献
4.
According to human history,there are varieties of ways through which the feminine aspect of nature faced and in many cases,overcame oppression.One of the ways this phenomenon displays itself is in the literary works that we deem as realistic and an expression of the norms and customs of the society in question.Sister Carrie and My Antonia are two such literary pieces that embody the struggles and triumphs of women in the 19th and most of the early 20th century.In creating such monumental and naturalistic adaptations,both authors are able to present the case of two migratory women from different backgrounds but confined by the norms and mannerisms of the society around them.The struggles that each of these characters undergoes is an expression of the underlying constraints that the paternal and chauvinistic society of their time places upon both women and the natural world.The eco-feminist agenda,however,gets a more elaborate representation in My Antonia than in Sister Carrie due to a variety of factors that serve to illuminate the differences between these two iconic stories.This paper makes a thorough comparison between two literary works—Sister Carrie by Theodore Dreiser and My Antonia by Willa Cather from the perspective of eco-feminism. 相似文献
5.
Based on the surface energy balance model which is widely used abroad, a temperature and humidity field coupling model of conservatory soil without crop vegetation in full illumination was established. Considering the relatively closed environment in conservatory, weak solar radiation and little surface evaporation of soil, the daily variation of water content in different soil layers may be neglected, then the temperature and humidity field coupling model was simplified to a one-dimensional thermal diffusion model. The simplified model and the temperature and humidity field coupling model adopted the same computational method of soil physical parameters and discrete format of heat diffusion differential equations, and were applied to the continuous simulation of temperature field in conservatory soil without crop vegetation in full illumination. Through the comparison between simulation results and experimental data, the precision of the simplified model was verified. The typical rule of soil heat flux variation in a 24 h cycle was also obtained. 相似文献
6.
WANG Su-nan PAN Yun-he YANG Jian-gang 《浙江大学学报(A卷英文版)》2007,8(8):1290-1295
Research on information spillover effects between financial markets remains active in the economic community. A Granger-type model has recently been used to investigate the spillover between London Metal Exchange(LME) and Shanghai Futures Exchange(SHFE) ,however,possible correlation between the future price and return on different time scales have been ignored. In this paper,wavelet multiresolution decomposition is used to investigate the spillover effects of copper future returns between the two markets. The daily return time series are decomposed on 2n(n=1,…,6) frequency bands through wavelet mul-tiresolution analysis. The correlation between the two markets is studied with decomposed data. It is shown that high frequency detail components represent much more energy than low-frequency smooth components. The relation between copper future daily returns in LME and that in SHFE are different on different time scales. The fluctuations of the copper future daily returns in LME have large effect on that in SHFE in 32-day scale,but small effect in high frequency scales. It also has evidence that strong effects exist between LME and SHFE for monthly responses of the copper futures but not for daily responses. 相似文献
7.
卢东强 《上海大学学报(英文版)》2004,8(1):8-12
Based on the complex dispersion relation for the two-dimensional free-surface waves generated by a moving body in the steady Oseen flows, the effect of viscosity on wavelength and wave amplitude was investigated by means of an asymptotic method and a numerical analysis. A comparison between the asymptotic and numerical analysis for the viscous decay factor demonstrates the validity of the perturbation expansions for the wave profile. The numerical result shows that the wavelength of viscous wave is slightly elongated in comparison with that of inviscid wave. 相似文献
8.
This paper presents a novel mega-Hz-level super high frequency zero-voltage soft-switching converter for induction heating power supplies. The prominent advantage of this topology is that it can absorb both inductive and capacitive parasitic components in the converter. The switch devices operate in a zero-voltage soft-switching mode. Consequently, the high voltage and high current spikes caused by parasitic inductors or capacitors oscillation do not occur in this circuit, and the high power loss caused by high frequency switching can be greatly reduced. A large value inductor is adopted between the input capacitor and the switches, thus, this novel converter shares the benefits of both voltage-type and current-type circuits simultaneously, and there are no needs of dead time between two switches. The working principles in different modes are introduced. Results of simulation and experiments operated at around 1 MHz frequency verify the validity of parasitic components absorption and show that this convener is competent for super high frequency applications. 相似文献
9.
The flooding distance is an important parameter in the design and evaluation of a routing protocol,which is related not only to the delay time in the route discovery,but also to the stability and reliability of the route.In this paper, the average flooding distance (AFD) for a mobile ad hoc network (MANET) in a random graph model was given based on the dynamic source routing (DSR) protocol.The influence of spatial reuse on the AFD was also studied.Compared with that in the model without the spatial reuse,the AFD in the model with the spatial reuse has much smaller value,when the connetivity probability between nodes in the network is small and when the number of reused times is large.This means that the route discovery with the spatial reuse is much more effective. 相似文献
10.
Linguistics sexism exists in English at different levels and in many respects. It reflects the restrictions of the society, and in turn, is resulted from the inequality, stereotypes, religious beliefs and other aspects of the society. As a result of people’s raising awareness of equality between two genders, many measures have already been taken to reduce linguistic sexism in English, but it is impossible to eliminate it. 相似文献
11.
Wavelength and bandwidth allocation is important for multicast communication in optical networks. In this paper, a new method based on scheduling theory is proposed. The proposed method formulates wavelength bandwidth capacity as a large rectangle and these multicast stream bandwidth requirements as small rectangles. It treats the wavelength and bandwidth allocation question as a rectangle packing problem. The proposed algorithm solves the problem by taking quasi-human strategy with Euclidian distance. It is an effective heuristic algorithm to quickly solve multicast stream bandwidth allocation problem in optical networks by theoretic analysis. Further simulation experiments show the bandwidth allocation algorithm can increase network utilization and have a good fairness performance for unicast stream and multicast stream in optical networks. The results indicate the effectiveness of the algorithm. 相似文献
12.
目前广泛应用的TDM-PON技术采用不同时隙区分用户,可用带宽受到限制,为满足未来用户对高带宽的需求,需要研究无源光网络的平滑升级路径。分析了ION技术的速率升级、波长升级和空分升级方案,并重点介绍了波长升级的WDM-PON系统;最后提出了OCDMA-PON与OFDMA-PON两种可选方案。 相似文献
13.
把波分复用技术应用于计算机光互连网络 ,通过分析波长和网络路由之间的关系 ,提出了采用波长作为 IP寻径“网络地址”,实现网络间路由寻径的新概念 ,使网络具有非常好的可扩展性 .介绍了实验室利用双波长环网构成机群系统验证波长路由的工作进展及关键单元设计 .性能测试表明 ,光互连技术的应用 ,是解决网络带宽不足的理想技术 . 相似文献
14.
李旸 《孝感职业技术学院学报》2006,9(2):77-79
文章比较了多模光纤和塑料光纤的结构参数和模式数量,并对大量的模式色散会严重限制光纤的带宽作了分析。根据选择性激发能够有效减少模式色散从而能提高带宽的原理,提出了一种针对塑料光纤通信的新复用技术。 相似文献
15.
16.
“尚和”是中日两民族伦理文化历史长久积淀的产物,也是两民族重要的道德价值观和伦理法则。“和”伦理对中日民族各自的社会人伦关系、思维方式以及社会的发展产生了深远的影响。但是，中日民族关于“和”伦理的内涵、特征及其实现的途径和方式等方面存在着较大的差异性。 相似文献
17.
Christina N. Baker 《The Urban Review》2013,45(5):632-650
This study focuses on how personal support from the college environment influences the academic performance of African American and Latino college students attending selective colleges. Under-represented students at selective colleges continue to face challenges to their academic success, and support from the college environment is a key factor in the academic success of many of these students. The results indicate that it is important to distinguish between different forms of personal support and the race and gender of students receiving support. However, I find that the influence of faculty, specifically support from faculty of color, is important for the success of African American and Latino students at selective colleges. 相似文献
18.
The chromatic dispersion( CD) degrades themodulation-phase relationships of lightwave signals,reducing information-carrying capacity through pulse-broadening in digital networks and distortion in analogsystems[1,2]. The widespread use of dense wavelengthd… 相似文献
19.
介绍了在法拉第效应实验中确定样品介质的色散dn／dλ和波长λ之间关系的两种方法。 相似文献
20.
以波分复用(WDM)技术的原理为基础,分析了信号频带、信号的放大和非线性困扰,以及波长变换技术。得出了要实现宽频带、多信号的较好传输信号,必须考虑放大器的增益平坦、噪声以及WDM系统的非线性,而且信号间的畅通传送,波长变换技术也是必不可少。 相似文献