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关键词： 钻机   旋转密封   设计  

摘要： 根据坑道钻机使用的液压离合器液压旋转通道的密封设计要求,对其使用的结构形式、密封原理、性能评价、材料选择作分析讨论。

关键词： 魔力   离合器   子张  

摘要： 有些字带有魔力，一旦使用，就会登入现实。“离合器为什么要叫离合器？”儿子张容问我。我画了一个歪歪斜斜的锥形离合器。“一个连续转动的主动轴就是这样驱动一个原先不会动的驱动轴的。”

关键词： 湿式离合器   分形理论   接合特性   重载  

摘要： 为了进一步提高和改善重载湿式离合器在使用过程的接合特性,结合分形几何理论建立重载湿式离合器接合特性计算模型,最后通过理论与试验手段获得重载湿式离合器摩擦副接触区域微凸体接触面积、分形维数及轮廓幅值尺度因素等对接合摩擦力的影响规律及湿式离合器摩擦温升变化规律。分析结果表明,不考虑微凸体作用分形维数与实际接触面积的增加,将会使湿式离合器摩擦力增加;考虑微凸体作用分形维数与实际接触面积的增加,将会使湿式离合器摩擦力降低;对于摩擦副接触面幅值尺度因素,随着其降低,将会导致各工况下摩擦力与最大温升变化幅值上升;通过试验验证,分形理论下理论计算结果与试验测定结果基本吻合。

关键词： 带压钻孔机   液压系统   离合器   油缸  

摘要： 世界上绝大多数国家和我国的石油行业扳孔均采用原有技术开井方法:手工钻孔或火电焊切割.这两种操作方法危险性大,由于井内状况不熟悉,钻孔时易产生火花,容易造成爆炸及井喷等.本液压带压钻孔机进行集中控制,或实现工进、快进、快退、速度可调、保压等多种功能.全部采用无极液压调速,可调整出相应的切削速度、切削进给量以及钻杆的转速.

关键词： Energetic expenditure   Social facilitation   Aggregation   Clutch size   Brisbane river turtle   NOCTURNAL EMERGENCE   RIVER TURTLE   SEA-TURTLES   INCUBATION-TEMPERATURE   TEMPORAL PATTERN   CHELONIA-MYDAS   GREEN   HATCHLINGS   METABOLISM   ENERGETICS  

摘要： Hatchling turtles typically emerge from underground nests in groups, so the nest escape process may represent another example of animals sharing a task (in this case, digging out of a nest) to save on individual energy expenditure. Previous studies have reported the energetic cost of embryonic development across chelonian taxa, but none has quantified the extra amount of energy needed to escape the nest. Brisbane river turtle (Emydura macquarii signata) hatchlings were found to fuel this activity by using approximately 50 % of their residual yolk energy content. An open-flow respirometry system was used to quantify the effect of clutch size on an individual's energetic cost while digging out of the nest. The energetic cost of nest escaping 15 cm upward in the fine moist sand was calculated to be between 0.34 and 2.32 kJ per individual depending upon the number of hatchlings digging together. The energetic cost decreased as the number of individuals digging together increased and thus supports the 'social facilitation' hypothesis which suggests hatchlings cooperate to share the workload of digging out of the nest amongst clutch mates to reduce individual energy expenditure. The reduced energetic cost associated with large cohorts was chiefly caused by the shorter time taken to dig out of the nest by larger numbers of individuals. We conclude that synchronous digging activity of many individuals during nest escape evolved not only to facilitate quicker nest emergence but also reduce the energetic cost to individuals.

关键词： Epithelial ovarian cancer   LIN-28B/let-7a/IGF-II axis   Molecular subtype   Prognosis   LET-7 MICRORNA BIOGENESIS   GROWTH-FACTOR-II   LIN28B   PROGRESSION   EXPRESSION   SURVIVAL   DISEASE   STEM   CHEMOTHERAPY   MODULATION  

摘要： Objectives. Aberrant expressions of LIN-28B, let-7a and IGF-II occur in epithelial ovarian cancer, and the LIN-28B/let-7a/IGF-II axis is associated with human disease. The purpose of this study was to investigate the associations between LIN-28B/let-7a/IGF-II axis molecular subtypes and epithelial ovarian cancer prognosis. Methods. Using quantitative reverse transcription PCR, we analyzed LIN-28B, let-7a and IGF-II mRNA in 211 primary epithelial ovarian cancer tissues, and also performed Classification and Regression Tree (CART) and survival analyses. Results. Four terminal subtypes were identified in the CART analysis in combination with survival analysis. Kaplan-Meier survival curves showed that subtypes LIN-28B(low)let-7a(low) and LIN-28B(low)let-7a(high) IGF-IIlow had significantly better survival than subtypes LIN-28B(high) or LIN-28B(low) let-7a(high) IGF-II (high) (p < 0.0001 for overall, p = 0.017 for progression-free survival, respectively). Multivariate Cox regression models showed that compared to subtype LIN-28B(high), subtypes LIN-28B(low)let-7a(low) and LIN-28B(low)let-7a(high)IGF-IIlow had significantly reduced mortality and reduced relapse risks. Moreover, subtype LIN-28B(low) let-7a(low) had better response to chemotherapy than subtype LIN-28B(high). Conclusions. These results suggest that molecular subtypes of the LIN-28B/let-7a/IGF-II axis associate with heterogeneous progression and may have clinical implications in predicting epithelial ovarian cancer prognosis. (C) 2016 Elsevier Inc. All rights reserved.

关键词： Wet clutches   Water contamination   Lubricant additive   Surface chemical analysis   FRICTION   LUBRICATION   HUMIDITY  

摘要： Lubricated friction interfaces used for wet clutches produce different friction behaviours depending on the lubricant conditions. Usually the lubricant conditions vary for water contamination in automatic transmission fluid (ATF). The presence of water retards the ATF performance by increasing the friction and can influence the deterioration of the clutch plates. Water as a polar contaminant can change the absorbability of the surface active additives, which might cause the characteristic friction behaviour. The aim of this paper is to verify the surface chemistry of tribotested standard friction interfaces lubricated with water contaminated commercial ATF (DEXRON (R) VI). The evidences of the influence of water on ATF performances were shown by surface analyses. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Torque phase   Micro-slip   Clutch control   Automatic transmission   VALIDATION  

摘要： Control over the clutch during gear shift is the key technique in automatic transmission shift control and this control largely decides the shift quality. The engagement of the on-coming clutch and the disengagement of the off-going clutch should be controlled synchronously and accurately to achieve a smooth shift. Optimal control of clutch torque exchange phase is required to achieve this synchronous and accurate control. Shift quality can be easily influenced with inappropriate control parameters because of the many factors that affect the torque phase, as well as the use of closed-loop control. In this study, a dynamic model of frictional clutch with electro-hydraulic shift control is built. On the basis of the study of the influence of clutch-related parameters, an optimal control model is proposed with the closed-loop control together with an adaptive control method based on micro-slip clutch control. This control method can continually self-adjust control parameters to prevent shock, improve control precision and effectively reduce the calibration work after. Test result shows that this closed loop with adaptive method ensures consistently good shift quality.

关键词： Stir casting   Composites   Microstructure   Aluminium   SiC   Al2O3 reinforcement   Mechanical properties  

摘要： Aluminium metal matrix composite is one of the most promising engineering material and gradually emerging technology in automobile industries. There are usage of this composite material in certain critical applications like clutch pressure and face plate assembly due to their enhanced mechanical, wear and physical properties. In the present study, A356 aluminum alloy reinforced with SiC and Al2O3 particle was made by stir casting process. The effects of different volume fractions of SiC and Al2O3 particle reinforcement on microstructure and mechanical properties have been investigated. The tensile, yield strength and hardness have been increased in the particulate containing composites. As compared to base alloy, 20 % volume fraction of SiC reinforced composites showed 16 % increase in tensile strength and 10 % volume fraction of Al2O3 reinforced composites showed 19 % increase in tensile strength. The yield strength of 20 % SiC and 10 % Al2O3 containing samples nearly 50 % higher than those of the base alloy. Dislocation density, precipitation hardening and changes in grain size are the main mechanisms enhancing the mechanical properties of particulate reinforced composites. The 20 % SiC and 10 % Al2O3 reinforced composites have been identified as optimized composites for clutch pressure/face plate application.

关键词： 双离合器   A3   事故车   行车电脑   干式   控制单元   机电控制   输入轴   输入转速   单元记录  

摘要： 车型：一辆2015年生产的奥迪A3,搭载CSS 1.4T 110k W高功率发动机和0CW 7速干式双离合器变速器,行驶里程为12899km。故障现象：该车为事故车,更换了机电控制单元总成和双离合器总成。交车后客户电话反映该车仪表的行车电脑会偶发的报离合器过热的提示,而熄火一段时间后再启动又恢复正常,频率不高,