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关键词： 二轴   稳瞄转台   环境试验   结构设计  

摘要： 星载小型二轴稳瞄转台是空间产品,它可以实现对成像系统光轴的稳定及对目标的跟踪。首先根据产品设计要求、空间产品环境要求及试验大纲,设计二轴稳瞄转台结构。其次基于ANSYS Workbench平台,按照环境试验要求对二轴稳瞄转台进行环境仿真分析,分析结果表明,星载小型二轴稳瞄转台结构设计合理,具有较好的抵抗加速度载荷、正弦载荷及随机载荷。最后对已加工装配的二轴稳瞄转台进行随机振动试验,结果表明结构设计满足设计要求,分析结果正确合理。

关键词： 湿式离合器   制动器   压力机   干式离合器  

摘要： 本文介绍了几种湿式离合器和制动器在压力机中的应用．并对湿式离合器／制动器与干式离合器／制动器进行了比较。

关键词： antipsychotics   diabetes mellitus   hypothalamic-pituitary-thyroid axis   metformin   thyroiditi  

摘要： Metformin was found to reduce elevated serum thyrotropin levels, and this effect was partially determined by endogenous dopaminergic tone. The aim of this study was to compare the effect of metformin treatment on hypothalamic-pituitary-thyroid axis activity in elderly women with subclinical hypothyroidism treated with antipsychotic agents and not receiving this drug. The study population consisted of 34 elderly women with subclinical hypothyroidism, 16 of whom received antipsychotic drugs. Because of coexistent type 2 diabetes, these women were treated with metformin (2.55-3 g daily). Glucose homeostasis markers as well as serum levels of thyrotropin, free thyroid hormones and prolactin were measured at the beginning of the study and 6 months later. Thirty women completed the study. With the exception of prolactin, baseline serum levels of the assessed hormones were comparable in both study groups. Although metformin reduced serum thyrotropin levels in both groups, this effect was more pronounced in the antipsychotic-treated than in the antipsychotic-naive patients. The effect on serum prolactin was observed only in antipsychotic-treated patients. The impact on serum thyrotropin levels correlated with improvement in insulin sensitivity and with a reduction in prolactin levels. Free thyroxine and free triiodothyronine remained at a similar level throughout the study. The obtained results indicate that metformin reduces serum thyrotropin levels in elderly women, and this effect is particularly pronounced in women with diminished dopaminergic transmission.

关键词： Takydromus sexlineatus   Maternal warming   Reproductive frequency   Embryonic mortality   Hatchling phenotype  

摘要： The understanding of life-history responses to increased temperature is helpful for evaluating the potential of species for tackling future climate change. Herein, adult southern grass lizards, Takydromus sexlineatus, were maintained under two thermal regimes simulating current thermal environment and a 4 degrees C warming scenario to determine the effects of experimental warming on female reproduction and offspring phenotypes. Experimental warming caused females to oviposit earlier and more frequently;however, it did not affect other reproductive traits, including clutch size, egg mass and clutch mass. Accelerated embryonic development and energy accumulation rate might have occurred in warmed females. Maternal warming appeared to increase early embryonic mortality, but did not shift hatchling size and locomotor performance. Embryos of oviparous lizards might be more vulnerable to climate change at early stages than at later stages. The impacts of climate change in oviparous lizards might be adverse in the longer term because of the shift in pre-ovipositional embryo viability, which possibly led to a decreased number of hatchlings.

关键词： mechanobiology   cell adhesion   focal adhesions   integrins   cadherins  

摘要： The linkage of cells to their microenvironment is mediated by a series of bonds that dynamically engage and disengage, in what has been conceptualized as the molecular clutch model. Whereas this model has long been employed to describe actin cytoskeleton and cell migration dynamics, it has recently been proposed to also explain mechanotransduction (i.e., the process by which cells convert mechanical signals from their environment into biochemical signals). Here we review the current understanding on how cell dynamics and mechanotransduction are driven by molecular clutch dynamics and its master regulator, the force loading rate. Throughout this Review, we place a specific emphasis on the quantitative prediction of cell response enabled by combined experimental and theoretical approaches.

关键词： LUBRICATION & lubricants  

摘要： The article reports that engineering company Eaton has enhanced its heavy duty after market clutches to improve performance, by upgrading the bearing and provider wider thrust pads, and talks of ease of routine lubrication with reduced driveline vibration and maintenance.