Counterformal contacts of full toroidal continuously variable transmission

1 Introduction A traction drive is a device, which transmits powerby means of traction contacts among multiple rotatingbodies. Variable ratio power transmission is achievedby varying the system geometry so that the points ofaction of the traction force are varied. When this isdone in a continuous manner, it results in a conti-nuously variable traction drive varaitor. There areprimarily two types of traction drives that are ofinterest in the automotive area, viz., half toroidaltraction drive an…     

An overview on research developments of toroidal continuously variable transmissions

1. Introduction Over the past century, the advancements of research and development in fuel economy and emissions have been retarded, in spite of implementation by depleting a lot of money. Thus, the ideal interim solution is to further optimize the overall efficiency of internal combustion engine (ICE) vehicles. One potential solution to treat the fuel economy dilemma is the toroidal traction drive CVT, an old concept that has only recently become the hope to automotive makers. Toroidal C…     

Calculating method of contact stress for non-circular gears

According to Hertz theory, the difference of contact stress for non-circular gears and equivalent gears is compared in the paper, a calculating method of contact stress for non-circular gears by using equivalent gears is researched, and computing formulas of power and rotation speed for equivalent gears are deduced. A numerical simulation of contact stress for non-circular gears has also been conducted based on the finite element method. By the comparison of fitting curves, the feasibility of using equivalent gears instead of non-circular gears to calculate the contact stress is testified.     

高职教师的职业倦怠与工作压力的关系研究

近年来,大力发展职业教育的号角已经吹响。高职作为职业教育的“领头羊”,其教师的工作状态备受关注。同时,教师工作压力和职业倦怠问题是近年来心理学界研究的焦点之一。因此,研究高职教师职业倦怠与工作压力的关系,对高职教育的健康发展大有裨益。     

应激研究综述

国内外对应激理论进行了研究，包括应激的含义，应激的生理机制以及应激发展过程中的几种主要理论模型；刺激理论模型、反应理论模型、CPT理论模型、系统理论模型。以往应激研究中还存在着问题，今后的研究还须努力解决。     

廉江市粤客词汇相似度的计量分析

本文采用语素和构词法分项统计的方法,对粤西湛江市所辖廉江市的粤语和客话的900余条日常词语进行了计量分析,并对照粤语代表广州话和客话代表梅州话同批词语的相关系数,从中窥探粤西粤客杂处地区方言接触的事实和接触程度。     

Influence of the ambient air temperature on the electrical contact reliability of electromagnetic relay

The dynamic contact resistances of HH52P electromagnetic relays are measured under different ambient air tem- perature. Their diagnostic parameters are extracted and determined. It is found that the ambient air temperature obviously influ- ences some parameters. In order to research its influence on the electrical contact reliability of electromagnetic relay, the statistic analysis is applied to study the static contact resistance, the max of the dynamic contact resistance and the bounce time. It is found that the ambient air temperature regularly influences the three parameters. Thoroughly, the phenomenon is studied and analyzed in the point of material science so as to probe into the essential matter of it.     

企业员工工作压力相关因素研究

对300名企业员工进行的预调查研究,得出了企业员工认为影响工作压力的30个因素,在此基础上编制了正式的调查表,以贵阳市的500名企业员工为调查对象,要求他们对各因素的重要性进行评分。结果显示,企业员工认为影响工作压力的因素是组织、群体、个体和社会四个方面,认为目前的工作压力主要是竞争加剧、低适应性、低文化素质、机构调整和技术变化等,而性别、年龄和学历等因素对企业员工的工作压力影响也十分显著。     

音乐活动：人以美的音响符号进行情感交流的特殊方式

音乐活动是作曲家、演奏家和欣赏者以美的音响符号为中介进行的情感交往的特殊方式。在音乐创作环节中，表现为作曲家主体的本我的情感与物化为他我的符号文本的情感的自我交往；在音乐演绎环节中，表现为演绎者与作曲家以乐谱符号文本为中介的心灵－精神交往方式；在音乐欣赏环节中，则表现为聆听者通过音响符号这个中介与演绎者和作曲家进行的心灵—精神的双重交往。     

磁场对绿豆芽长及超氧化物歧化酶的实验研究

用恒定强度的磁场(1T)对绿豆进行不同时间的处理,得出了不同磁场处理时间和培养时间对绿豆芽长和超氧化物歧化酶(SOD)活性的影响。实验结果表明:恒定磁场强度下不同处理时间对绿豆的芽长和SOD活性是有影响的,磁场强度为1T时,在6个处理时间中,30 min处理组在每次测量时芽最长。对绿豆的SOD测定表明:经过磁场处理后的绿豆SOD含量产生了明显的差异,培养时间为7 h的实验组在各磁场处理时间下的SOD活性均高于对照组,在培养21 h后差异最大;磁处理具有滞后效应,磁处理短期内并不产生明显的效果;豆芽SOD含量和芽长并不成对应关系。     

轮对前2阶弯曲模态对动力学行为的影响

研究目的：扩展动力学模型的分析频域,建立能考虑轮对柔性的车辆轨道耦合动力学系统模型,为研究轮轨磨耗的形成和发展以及轮轨噪声的来源提供基础。创新要点：利用欧拉梁横向弯曲模型,建立轮轴在垂直于轨道平面和平行于轨道平面内的弯曲振动模型;建立考虑轮轴弯曲的轮对模型与轮轨接触模块之间的耦合关系,进而研究轮轨接触行为受轮轴弯曲变形的影响。研究方法：1．把轮轴模拟为欧拉梁,左右车轮模拟为固结于轮轴上的质量块;2．假设左右车轮始终垂直于轮轴,引入虚拟的两个半边刚性轮对模型,建立轮轨接触模型和柔性轮对耦合的关系;3．基于多刚体车辆．轨道耦合动力学模型,利用以上柔性轮对模型和此耦合关系,建立考虑轮轴柔性的车辆一轨道耦合动力学模型。重要结论：1．建立的刚柔耦合的车辆．轨道耦合动力学模型能够有效地描述轮轴弯曲对轮轨接触行为的影响;2．在0-150Hz的随机不平顺激励下,多刚体模型和考虑轮对柔性的模型受到的轮轨力和轮轨接触点轨迹不同;这主要是由第1阶弯曲模态被激发导致。     

碱胁迫对叶片延迟发光的实验研究

选用绿宝石喜林芧叶片为材料,用BPCL型微弱发光测量仪测量了叶片经高浓度NaOH溶液处理后的延迟发光情况。结果发现:同一个叶片随着处理时间的延长,其延迟发光最初值和最后100s的光子数都先有一个小幅度的上升,然后又迅速下降;不同的叶片在相同的处理时间下,随着NaOH质量分数的增加,延迟发光最初值和最后100s的光子数都呈现上升的趋势,NaOH质量分数越大,上升得越快,随着处理时间的延长,上升的趋势变得越来越缓,最后各曲线越来越接近,且趋于平稳。整个实验表明,延迟发光可以规律性地反应碱胁迫对叶片的伤害程度,这为生物物理方法测量外界胁迫对叶片的影响提供了参考。     

讲授"圆轴扭转时剪应力公式推导"的一种新方法

建议采用解静不定问题的力学思想导出圆轴扭转剪应力公式，从而加强学科思想的教学。     

A parametric sensitivity study by numerical simulations on plume dispersion of the exhaust from a cryogenic wind tunnel

The low temperature plume exhausted from a cryogenic wind tunnel may sink down, posing a severe threat to public health and safety. Quantitative risk assessment of cryogenic plume flow behavior therefore plays an important role in the design and optimization of a cryogenic wind tunnel. A numerical model with a modified Hertz-Knudsen relation considering the phase change physics of the small quantity of water involved is applied to analyze the dispersion of the low temperature nitrogen plume exhausted from a 0.3 m cryogenic wind tunnel. The homogeneous multiphase flow is modeled using the single-fluid mixture model. A model validation is presented for the exhaust plume from the US National Transonic Facility (NTF). The predicted results are found to be better than those predicted by National Aeronautics and Space Administration (NASA)’s two-stage analytical model. The influences of the environmental wind speed, the environmental wind temperature, the relative humidity, and the exhaust flow rate, on low temperature nitrogen plume dispersion are obtained. In particular, the parametric sensitivities of different influence factors are analyzed. The environmental wind temperature and the exhaust flow rate of the nitrogen gas have greater impact on the temperature of the plume near the ground than do the environmental wind speed and the relative humidity. The exhaust flow rate of the nitrogen gas has greater impact on the oxygen concentration near the ground than does the environmental wind speed, while the environmental wind temperature and the relative humidity have negligible impacts. The results provide guidance on the operation and design improvement of a cryogenic gaseous nitrogen discharge system to avoid its potential hazards.     

操作系统内核的安全访问控制模型研究

本文在RBAC96模型上做了多次改进并给出一个改进的应用在linux操作系统上的RBAC模型,提出了激活角色集合以满足最小特权原则,将进程和用户做为主体,引入权限三元组来描述权限和客体操作之间关系,最后给出了系统中实现的逻辑结构。     

高校辅导员心理应激研究

高校辅导员中存在的心理应激现象,对辅导员队伍的建设、学生的成长进步以及思想教育工作的开展会产生不良影响。研究辅导员心理应激的形成、影响、应对,解决好高校辅导员群体的心理应激,维护好其心理健康,保持高校辅导员队伍的思想稳定,是当前高等院校管理不容忽视的一项重要工作。     

不锈钢基体激光熔覆Ni60A的残余应力研究

选择激光功率、扫描速度、送粉量为影响因素,用正交试验方法研究了不锈钢基体激光熔覆Ni60A的残余应力;结果表明:影响残余应力的关键因素为扫描速度,其次是激光功率,最后为送粉量;扫描速度180 mm/min、激光功率1.5 kW、送粉量3 g/s产生最小残余应力;此时熔覆材料Ni60A与基体形成良好的冶金结合,熔覆层组织均匀,无微裂纹等明显缺陷。研究结果为叶轮和螺杆的激光熔覆再制造提供了实验依据。     

论校本管理理论

校本管理(school-based management)是西方20世纪80年代学校改革运动中出现的一种新的教育管理模式,它强调教育主管部门应将其权力逐渐下放给学校,给予学校更大的权力和自主决策的空间,使学校能够按照自己的意愿和具体的情况来决定资源的分配、学校财政的预算、课程的设置、教科书的选择、学校人事决策等方面的改革措施,从而达到变革学校已有的管理体系,优化学校教育资源,提高学校的办学质量.围绕着这一理念,校本管理强调学校管理的人性假设、管理的原则、管理的策略、管理的机制都应该发生转变.     

A Study on the Characteristics of Chinese Pidgin English

Chinese Pidgin English is a variety of the English language.It is one product of language contact.It is a blend;in vocabulary,pronunciation and grammar,it is simplified and localized.It is one kind of spoken language without formal rules,but it plays an important part in the evolution of language.     

高校学生社团发展周期与运行机制相关性研究

高校学生社团的发展是有周期性的,不同社团在召集、磨合、成熟、弱化、断裂的周期过程中表现出不同的生命力特征：从量上看各周期跨度不一致,从质上看管理成熟度、成员满意度和外在影响度不一致。根据不同的管理结构模式,可以将高校学生社团的运行机制分为专制型、民主型和松散型三类,每种类型对应着不同的社团发展周期与特征。要构建可持续发展的运行机制,社团需注意以下几方面,即召集期平衡广度与效度,磨合期注重科学引导,成熟期拓展社员参与,衰退期抓实文化传递。