课程文献中心 更多>>

关键词： 平面研磨机   锥齿轮   平动   行星运动  

摘要： 为了实现较大工件的平面研磨,研磨机需要完成大回转直径的行星运动。通过分析工件与研磨盘的相对运动,确定了获得较佳研磨效果的研磨轨迹和研磨速度,然后分析了采用锥齿轮传动实现研磨工件的大回转直径平动的可行性,设计了锥齿轮传动平面研磨机的主传动系统的具体传动机构,并对锥齿轮传动的主要参数进行了设计计算。对锥齿轮传动行星运动传动比进行了计算,通过合理选择各锥齿轮齿数,实现了工件的平动。加大锥齿轮传动轴的长度,可以获得更大回转直径的平面研磨运动。

关键词： 带式输送机   GCD无齿轮传动   特大功率   驱动系统  

摘要： 阐述了中煤大海则煤矿主井带式输送机前期驱动系统方案的设计及选用论证,介绍了国外用于特大功率带式输送机驱动系统的传动方式——GCD无齿轮传动系统,该传动方式的设计理念将给传统带式输送机的传动方式的设计理念和思路给予一定启示。

关键词： 拖拉机   故障   离合器   变速箱  

摘要： 拖拉机是农业生产当中最常见的农业机械之一,在农业生产过程中发挥着重要作用。拖拉机的使用技术固然重要,但是如何解决拖拉机故障的方法也十分关键。作为一名合格的农机手,不但要掌握好拖拉机驾驶技术,还要了解并熟知遇到问题的解决方案,防患于未然。本文主要介绍了拖拉机离合器和变速箱常见故障的解决办法。

关键词： SSS离合器   燃气轮机   热效率   超临界机组   热电联产技术   传动装置   离合器装置   超超临界  

摘要： 据2014年6月27日《北极星电力网》报道，“机组的年平均全厂热效率提高约10％，机组的热效率优于现有的纯凝超超临界百万机组（平均热效率约为45％）。”6月26日，在北京召开的由英国SSS传动装置公司和康达科技信息（国际）有限公司联合主办的SSS离合器在***（热电联产技术凝抽背）的应用研讨会上，有60多年历史的英国SSS传动装置公司总裁詹姆斯．尼维斯表示，在燃气轮机里加入SSS离合器装置，其发电煤耗比常规350MW超临界机组减少约14克／千瓦时，提高了项目的盈利水平。

关键词： UG   二次开发   参数化   谐波齿轮  

摘要： 采用UG/Open API技术和VC++联合开发,通过UIStlye交互式对话框实现谐波齿轮传动系统的参数化设计。研究UG二次开发主要流程及关键开发技术。二次开发系统界面简洁,操作方便,可以提高谐波齿轮的设计效率,为不同材料、不同结构的谐波齿轮传动系统的受力分析打下了基础。

关键词： 面齿轮   啮合性能   拓扑修形   主动设计   齿面接触分析  

摘要： 为了提高面齿轮的磨齿效率,采用不做齿向进给运动的大半径盘形砂轮磨齿得到的面齿轮具有近似齿面,然而该近似面齿轮与双向修形小轮的啮合性能不够理想。因此进一步通过啮合理论重新构造小轮齿面,并根据预设的啮合性能对该新构造的小轮齿面进行拓扑修形设计,以控制近似面齿轮传动的啮合性能。小轮的拓扑修形齿面采用盘形砂轮局部点共轭法磨齿加工,建立了小轮拓扑修形齿面与加工参数之间的线性方程。用实例说明了所提方法的应用,齿面接触分析结果与给定的啮合性能基本一致。

关键词： 自动变速器   离合器   建模   控制  

摘要： 设计了一种崭新的自动变速器离合器液压执行机构并阐述了该机构的组成以及工作原理,建立了自动变速器离合器液压执行机构的动力学模型,利用离合器液压执行机构台架进行了动态试验,所得试验结果与仿真结果基本一致,验证了仿真模型的有效性,设计的离合器回油管式液压系统能够实现较强的鲁棒性和准确性。

关键词： Ustekinumab   Stelara   Type 1 diabetes   IL-17   IFN-gamma   Clinical trial   REGULATORY T-CELLS   TH17 CELLS   IFN-GAMMA   DOUBLE-BLIND   IL-17   CYTOKINE   MICE   INFLAMMATION   INHIBITION   INDUCTION  

摘要： Type 1 diabetes (T1D) results from the autoimmune destruction of insulin-producing pancreatic beta cells. There is now mounting evidence that pro-inflammatory pathways, which are mediated by T cells that secrete IL-17 and IFN-gamma, play a critical role in the loss of beta cells. These data suggest that blockade of T cells that secrete IL-17 and IFN-gamma may halt or reverse disease in subjects with recent-onset T1D. Agents to facilitate this approach are currently in clinical use. Ustekinunnab, a humanized monoclonal antibody that targets the shared p40 subunit of IL-12 and IL-23, has been used for the treatment of psoriasis, an indication for which it has proven to be safe and effective. In this review, we summarize the evidence that supports a combined pathogenic role of IL-17 and IFN-gamma in the development of T1D, with the aim of providing a rationale for testing agents such as ustekinumab for the treatment of T1D. (C) 2014 Published by Elsevier Inc.

关键词： LAWYERS' fees   NONFICTION   UNITED States  

关键词： ACTH   adolescents   cortisol   diabetes   HPA axis   HORMONE STIMULATION TEST   PITUITARY-ADRENAL AXIS   CORTICOSTEROID-BINDING GLOBULIN   DOSE RESPONSIVENESS   INSULIN-TREATMENT   STRESS   SENSITIVITY   RESPONSES   HYPOGLYCEMIA   NEUROPATHY  

摘要： Context: Type 1 diabetes mellitus (T1DM) is a pro-inflammatory stress state, which, with its attendant hyperglycemia, likely disrupts hypothalamo-pituitary-adrenal (HPA) control, further dysregulating glucose homeostasis. Objective: To test the hypothesis that endogenous adrenocorticotropic hormone (ACTH)-cortisol dose-responsive drive, estimated analytically, is significantly accentuated in adolescents and young adults with T1DM compared with healthy individuals. Design, setting, patients, and interventions: This was a pilot study of 11 volunteers with T1DM and 10 controls, ages 16-30 yr, at a medical center. Subjects underwent overnight frequent blood sampling (every 10min for ACTH and cortisol and every 60min for blood glucose) from 10pm to 8 am. T1DM volunteers maintained their home insulin regimen. Main outcomes: Deconvolution analysis and dose-response estimates were the key outcomes. Results: Mean free cortisol, but not ACTH, concentrations were lower in the T1DM group compared with controls (p = 0.012). Non-invasive ACTH-cortisol dose-response estimates revealed that T1DM patients had reduced ACTH efficacy (maximal cortisol secretion, p = 0.009), reduced ACTH potency as quantified by greater EC50 (ACTH concentration driving half-maximal cortisol secretion, p = 0.04), and increased ACTH sensitivity (more positive ACTH-cortisol slope, p = 0.03). Post-hoc gender comparisons indicated that these differences were limited to females. Linear regression in women showed a strong correlation of both ACTH efficacy and EC50 with C-peptide levels (both p < 0.01). Conclusion: Compared with healthy individuals, T1DM patients manifest decreased overnight adrenal responsiveness to endogenous ACTH leading to lower free cortisol concentrations. These findings suggest impaired stress-related adaptations of the HPA axis in T1DM.