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关键词： Mathcad   Creo   齿轮   优化设计  

摘要： 传统的齿轮设计方法需要不断重复修改设计参数,过程繁琐、计算量大,笔者利用Mathcad与Creo集成的解决方案,通过Mathcad带单位计算功能实现以追求体积最小为目标的齿轮传动优化设计,并把设计结果传递给Creo建模,实现设计与制造数据的关联,提高了生产的效率,具有一定的工程实践价值。

关键词： 阀体   自动变速器   位置   易损   体相   离合器   执行元件   控制单元  

摘要： 在0AM自动变速器（大众7速干式双离合变速器）的维修中,很多人习惯于更换阀体总成来解决问题。但在有些情况下,装上新阀体后车跑了没多久就又开始出现问题。其实,我们在更换阀体之前,需要先检查各个执行元件（离合器）,然后检查驱动离合器的油压所经过的油路通道中是否有泄压。只有前面检查都没有问题了,才考虑更换或者检修阀体和变速器控制单元TCM。

关键词： 湿式离合器   细长轴   润滑   结构紧凑  

摘要： 介绍一种新型湿式离合器润滑装置。该装置结构紧凑、工作可靠、安装方便并能解决细长轴润滑管路布置难题,有效利用了零件自身结构特点,对摩擦副中零部件起到很好的润滑效果。

关键词： 干式离合器   出厂检测   试验台  

摘要： 介绍了双作用干式离合器出厂检测用试验台。该试验台体积小,操作简便,易于维护,可检测离合器结合分离效果、主分离杆和副分离杆的工艺是否在要求范围内。

关键词： 离合器   过热  

摘要： 船用湿式多片摩擦离合器(图1)的摩擦片在较高速度时容易发生滑摩或油膜剪切发热问题。这与润滑油油路结构、摩擦片油槽结构及离合器使用条件、摩擦片内部温度场、位移场有关,还与润滑及冷却介质的流场有关。本文着重对我局8000KW系列救助船舶所采用的湿式多片摩擦离合器在操作、维护和管理方面可能会引起多片摩擦离合器过热这个问题进行分析。

关键词： Bobwhite quail   Embryo   Hematology   Development   Hypoxic incubation   Fetal programming  

摘要： Hematology and its regulation in developing birds have been primarily investigated in response to relatively short-term environmental challenges in the embryo. Yet, whether any changes induced in the embryo persist into adulthood as a hematological form of "fetal programming" is unknown. We hypothesized that: 1) chronic as opposed to acute hypoxic incubation will alter hematological respiratory variables in embryos of bobwhite quail (Colinus virginianus), and 2) alterations first appearing in the embryo will persist into hatchlings through into adulthood. To test these hypotheses, we first developed an embryo-to-adult profile of normal hematological development by measuring hematocrit (Hct), red blood cell concentration ([RBC]), hemoglobin concentration ([Hb]), mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, as well plasma osmolality. Hct, [RBC] and [Hb] in normoxic-incubated birds (controls) steadily increased from similar to 22%, similar to 1.6 x 10(6) mu L-1 and similar to 7 g% in day 12 embryos to almost double the values at maturity in adult birds. Both cohort and sex affected hematology of normoxic-incubated birds. A second population, incubated from day 0 (d0) in 15% O-2, surprisingly revealed little or no significant difference from controls in hematology in embryos. In hatchlings and adults, hypoxic incubation caused no significant modification to any variables. Compared to major hematological effects caused by hypoxic incubation in chickens, the hematology of the bobwhite quail embryo appears to be minimally affected by hypoxic incubation, with very few effects induced during hypoxic incubation actually persisting into adulthood.

关键词： Nonlinear moving string   Transversal displacement   Boundary control of memory type   Uniform decay  

摘要： A nonlinear problem modeling a moving string with memory condition at the boundary is considered. This work aims at establishing reasonable sufficient conditions capable of suppressing the transversal vibrations that occur during the movement of the string. Unlike the fixed strings case here we need to employ the Reynold Transport Theorem to compute the "total" derivative. This results in the appearance of several boundary terms which necessitates appropriate handling. We shall prove that the motion of the string plays an important role in determining the rate of the decay of solutions.

关键词： Engine speed fluctuations   torsional vibrations   gear rattle   clutch pre-damper mechanism   idle rattle   powertrain vibrations   time-varying gear mesh stiffness function  

摘要： In this paper, the influence of clutch disk pre-damper mechanism constituents on the idle rattle phenomenon was investigated with an analytical model containing a new time-varying gear mesh stiffness function. Comparing experimental results to simulation results for the same excitation input was the key implementation for the validation of proposed model. The engine speed fluctuations represented in the simulation was imported from a speed measurement of a diesel engine in the test bench.

关键词： Random co-polyimide   6FDA-Durene-CARDO   Sour gas separation   Permeability coefficient   Selectivity coefficient  

摘要： A series of aromatic random co-polyimide membranes based on 6FDA-Durene/CARDO backbone with varying content of CARDO moiety (3:1;1:1 and 1:3) were synthesized for enhanced acid gas separation performance. Gas transport properties of pure and mixed gas streams consisting of H2S, CO2, He, CH4, N-2 and C2H6 through the dense films of the co-polyimide were studied. Mixed sweet gas tests were done with feeds containing no H-2 S up to 55 bar, while mixed sour gas measurements were conducted with feeds containing H2S up to 34 bar for 10% H2S and 20% H2S. The membranes exhibit very attractive pure gas transport properties, as CO2 permeability and CO2/CH4 selectivity are up to 323 barrer and 35 respectively. Furthermore, the transport properties of sour gas mixture consisting of five gases were also found attractive, as the CO2/CH4 and H2S/CH4 ideal selectivities are in the range of 18-23 and 19-21 respectively;while CO2 and H2S permeabilities are in the range of 38-51 and 40-47 barrers respectively for 20% H2S in the gas mixture. These values and separation performance exhibited by the co-polyimide are comparable and very competitive even, as compared to the values obtained in some of the high performance polymeric membranes that have been reported in the literature. The stability of the random co-polyimide 6FDA-Durene/CARDO membrane under these aggressive environments is quite remarkable.