随着航空、风电等装备对齿轮传动功率密度、承载能力、寿命要求的提高,齿轮接触疲劳失效成为限制现代齿轮装备服役性能与可靠性的重要瓶颈,其中,材料的微观结构特征从根本上决定了齿轮等服役件疲劳性能的优劣.通过调研国内外相关研究现状,介绍了齿轮材料中残余奥氏体、碳化物、晶粒等主要微观结构及其对齿轮接触疲劳性能的影响.归纳了现有基于微观结构建模和微结构力学本构模型的齿轮疲劳数值模拟方法,用来描述齿轮接触疲劳中的微结构力学行为,以提升对齿轮疲劳关键特征和机理的理解.重点对齿轮存在的多种接触疲劳失效形式进行了详细阐述,分析了影响齿轮接触疲劳失效的主导因素、诱发的微观结构与力学性能变化特征以及潜在机理.为进一步理解齿轮服役过程中的微观结构演化特征与力学性能退化的关联关系以及接触疲劳失效内在机理、形成高性能齿轮抗疲劳设计制造方法提供了参考.

Tooth bending fatigue remains as a fundamental bottleneck restricting the safety and reliability of modern high-performance gear. In this study, a serial of bending fatigue tests on case carburized and shot peening treated gears is conducted. The fatigue crack propagation behaviors during bending fatigue test were analyzed. The alternations of macroscopic mechanical properties and microstructure features of gear samples subjected to bending fatigue are experimentally examined and analyzed in detail. It is found that the measured tooth root crack trajectories basically conform to the dangerous section of the tooth root determined by the 30° tangent method with a slight variation of about 1°. The phenomena of residual stress relaxation in gear bending fatigue is observed with the maximum residual compressive stress decreasing from −698 MPa of intact state to −572 MPa of failure state. Furthermore, the content of retained austenite of tooth root surface decreases by about 3.8 % after the gear bending fatigue failure, and the grain size of the tooth root core region illustrates a certain tendency of coarsening.

传统宏观齿轮接触疲劳寿命预测方法基于均匀连续材料假设,未考虑多晶体的微观结构,难以描述材料的真实微观结构特征对齿轮滚动接触疲劳寿命影响.为了突破传统方法的局限,提出一种基于机器视觉数字图像处理技术,考虑材料真实微观结构的齿轮接触疲劳数值分析方法.首先,通过表征试验获取齿轮节点处啮合区域材料的真实晶粒形貌;其次,采用MATLAB图像处理工具箱识别晶粒形貌图像,生成真实微观几何拓扑结构;第三,构建弹塑性连续损伤耦合的本构关系,建立齿轮接触疲劳分析二维有限元数值模型;最后,研究齿轮循环受载历程中最大接触压力、晶界剪应力以及晶界损伤的分布情况,分析齿轮节点啮合区域不同微观结构特征对损伤的影响.研究结果表明:基于机器视觉的图像处理技术能很好地模拟齿轮材料的真实微观结构;在齿轮接触疲劳损伤过程中,最大接触压力呈现逐渐减小趋势;随着循环加载次数增加,损伤逐渐出现局部化现象;在损伤后期,采用图像处理法进行微观结构重构时,损伤速率显著加快.

随着社会的发展和科技领域的进步,高校思政工作需进行管理革新以适应时代的发展,而精细化管理作为科学管理理念中一个非常重要的管理方式,成为高校思政工作改革的方向.为此,实现高校思政工作领域的精细化管理目标,需在理解高校思政工作精细化管理的相关内涵和特征的基础上,把握高校思政工作的现状,积极探索精细化管理方式与高校思政工作领域的有机结合,从而提升高校思政教育工作质量.

结合应用型科技院校大学生的特点,采用问卷调查和受试访谈等方式,分析大学英语学习过程中负动机的主要影响因素,包括教师因素、教材、学习环境和学生自身因素.针对这些影响因素,建议采取丰富的教学方法,以便提高学生对英语学习的兴趣;科学编制教学资料,让学生感受到大学英语内容贴近生活,学习起来更加得心应手;营造良好学习环境,让学生在学习中身临其境.

The bat algorithm is introduced into spectrum allocation to avoid being easily trapped into a local optimization in cognitive radio.The binary bat algorithm is modified based on the spectrum allocation model to achieve better results.Firstly,the selection strategy of the bat algorithm is changed to greedy strategy which can improve the exploitation capability at the current position.Secondly,the distribution of the best position of each bat experienced is analyzed and the statistic characteristic of the bat's position is used to guide bats finding the optimal solution.It can enhance the speed of the convergence of bat algorithm.Finally,during the local search,the solutions are not obtained by mapping the real number to binary set but being updated directly in the discrete domain,which shortens the searching time.The simulation results show not only that the proposed algorithm is more efficient,but also the speed of convergence is faster than the conventional algorithm.

In order to reduce the operating costs of logistics system, and improve the operational efficiency of logistics system, this paper establishes the logistics node location models with the aim to minimize logistics system operation costs and maximize customer time satisfaction. In the process of research, aiming at the shortcomings of multiple objective par-ticle swarm optimization, it improves the algorithm from three aspects including external archive update, the choice of learning samples and particle variation. Finally the improved multiple objective particle swarm optimization is used to solve the logistics node location models. The result shows the improved algorithm has better distribution and convergence compared with other optimization algorithms.

Translation is the goal and means of learning a foreign language.Some ignored weaknesses have developed during the College English teaching process.Because of the transformation of Independ-ent Colleges and the increased score of translation item in CET-4 and CET-6 ,we urgently analyze the current situation of College English teaching and improve the quality of translation teaching.

近几年来,语言使用中的模糊现象引起了语言学家的广泛关注.对模糊语言和将模糊理论运用于各种文体的分析是近些年来中西方语言学家所致力于研究的课题,本文分析外交语言中模糊现象的特点及表现形式,并从语用的角度出发,对外交语言中模糊现象的功能进行分析和研究,发现外交官利用外交语言的模糊性能达到隐藏信息、表达谦逊礼貌、表明立场制造幽默等语用效果.

Due to the useful properties of nonvolatile,memory and nanoscale,memristors have prospective promising applications in artificial networks,pattern recognition and signal processing.This paper exploits the learning rule of the memristive network based on spiking timing dependent plasticity(STDP)and uses the genetic algorithms with self-adaptation and variable topologies,which allows the number of hidden neurons,connection weights,and connectivity pattern to change self-adaptably.Three memristor models are respectively used as the synapse in the network,including HP linear memristor,non-linear memristor and threshold memristor.The comparison of the performance of the three memristive neural networks is presented,and the hybrid memristive networks' learning effects are analyzed.

In order to reduce the complexity and subjectivity of establishing evaluation index system of teaching quality, an evaluation method based on PLS (Partial Least Square) path modeling was put forward. First after finding out a series of observation indicators about teaching quality, PLS path modeling was used to extract the relationship of some latent indexes by those indicators and data and to obtain the weights of the indexes. So teaching quality evaluation index system was established and improved. At last, the empirical experiment showed this method would be effective and feasible.

Taking Hallidy′s interpersonal function in systemic functional grammar as the theoretical frame-work,it analyzed interpersonal meaning in the over 65 advertising slogans of Coca-Cola and explored its means and strategies to realize interpersonal meaning through the language role played by different tone .It is not only a newly scientific linguistic evidence of manufacture and appreciation of advertising slogans , but also a creative exploration of the application of interpersonal meaning .

基于独立院校在招生层次上的特点，独立院校的学生在英语学习基础及学习能力方面与公办院校相比有一定的差距。而英语写作从来都是大学生最薄弱环节之一。发现独立院校学生在英语写作中的问题及成因并找出策略，利于学生掌握技巧提高写作能力，帮助独立院校在英语改革中取得进步。

In this paper,based on the theoretical analysis of influencing factors for farmers' willingness to participate in agricultural insurance,logistic regression model is established for the survey data of 503 households in Chongqing,and the study shows that the factors on the farmers such as sex,age,educational level,level of household net income,risk expectation for natural disasters,expectation for agriculture product prices,insurance payment levels and efficiency of insurance payment affect the willingness to participate in the agricultural insurance significantly,in which risk expectation for natural disasters and expectation for agriculture product prices are the most important ones,while the non-agriculture income level and government subsidies have no significant influence on the farmers' willingness.

The normal family of holomorphic functions is investigated in the notes,and the related theorem is obtained： Let F be a family of holomorphic functions,L（z） be a continuous function,and h（z）（■0） be a holomorphic function on domain D.For each f∈F,if f（z）≠L（z）,f′（z）≠h（z） and f′（z）=a as f（z）=0,where the complex number a satisfies ah（z）∈C-R,then F is normal in the domain D.

The substantial income disparity between urban and rural populations in income per capita has aroused lots of concern.This paper uses an over-lapping generation model to research the impact of public education and social security on the income distribution,and on this basis,we further examines the influence of public education and social security on the urban-rural income gap.Our research found: public education and social security affect income by human capital accumulation,while public education have impact on educational investment and social security act on effective family time,as both have influence on human capital accumulation.On the one hand,the simulation result shows the increasing of public education and social security can increase income significantly;on the other hand,combined with the real Chinese urban and rural,the empirical result show that public education and social security which have been expected to have regulated and narrowed the income gap in China,do not play the role of income redistribution,on the contrary,form the negative effects of reverse adjustment and expand the urban-rural income gap.This paper come to the conclusion that narrowing education investment per capita and social security tax rates between urban and rural areas will play a significant role in narrowing the urban and rural income gap,from our theory and empirical evidence.

The reform of course examination is a key to improving the quality of higher education.In view of the low efficiency of course examination in colleges,considering the engineering feature of specialized courses,the examination content is divided into 3 levels—memory,application and integrated application.The features and proportions of the 3 levels in course examination are analyzed.Midterm quizzes should focus on the first 2 levels while the final exam should emphasize the third level.Moreover,experiment examination is an effective approach to stimulate students' passion for experiments,which can objectively evaluate students' engineering ability.It is suggested that several experiment exams be given during the course,and exams cover most key skills.Finally,network course-management system provides an implementation platform for process evaluation which can effectively improve the fairness and efficiency of process evaluation.

To achieve the training objectives of logistics engineering research talents,the construction of a logistics engineering research education system including theory research class education system,practice innovation system and independent research system both in and out of the class was studied.The theory research class education system is constructed by heuristic teaching,case study and seminar.The practice innovation system is structured by professional foundation skill,professional synthesis designs,free elective course synthesis training and etc.The independent research system involves Student Research Training Programming(SRTP),National College of Innovative Pilot Scheme and National Logistics Design Competition and etc.The logistics engineering research education system attachs importance to both theory and practice to promote both learning and research,and to guarantee the effective cultivation of logistics engineering research talents.

Open laboratory is one of important bases for developing students' innovation capability and overall quality,the training in open laboratory is the important part to build capacity for logistics engineering research talents.From the experiment such as the basis of professional skills,professional integrated design,optional subjects based integrated training and research of innovative experiments with different degrees of experimental in open laboratory,students could gain the basic knowledge and basic skills,integrated design capabilities,the capacity for foresight and independent access to knowledge,questions,analyzing problems and problem-solving capacity of the basic research.

System evaluations are always able to use to guide improving of information systems and managers' decision-making in implementing, monitoring the effectiveness of software. However the evaluation happens to change as end users' usage. And then for capturing whether the changes exist and how to change in the operation of the system to maintain the software Sustainability, this paper used PLS (Partial least square) and statistic test models in the measure model of system evaluations. Data were collected from all users of a bridge management information system in a large metropolitan area (Chongqing city) in China at three points in time with an interval of 18 months between each collection of data, to examine the change of the software usage and the influence of three variables: `management effectiveness', `information service quality', and `training' on user satisfaction with the system. And the influence of `software technology level' on `user satisfaction' was also examined via three intervening variables mentioned before. Results suggest that the influence of `management effectiveness' significantly increased over time, the effect of `software technology level' on `management effectiveness' and `information service quality' significantly decreased over time, and the influence of `training' first increased then decreased. Finally, it is suggested that the bridge management system should be improved, starting with the above four variables.