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关键词： Carbon fabric reinforced phenolic composites   Engagement of wet clutch   Simulation   Analytical and experimental comparison   REINFORCED POLYETHERIMIDE COMPOSITES   NUMERICAL-SIMULATION   WEAR PERFORMANCE   FRICTION   ROUGH   BEHAVIOR  

摘要： Studying the wet clutch engagement more efficiently makes it necessary to simulate the wet clutch behavior. So, based on the modified Reynolds equation and torque balance equation, the modified numerical model was developed by introducing the carbon fabric contact coefficient and the surface pattern parameter for the carbon fabric wet clutch. It was found that there was a good agreement between computational results and experimental measurements. And subsequently, the influences of the applied pressure, the permeability and the fluid viscosity on the engagement characteristics were explored with the proposed numerical model. (C) 2015 Published by Elsevier Ltd.

关键词： Variable displacement pump   Constant pressure control   Variable speed control   Swash plate control   Power consumption  

摘要： In this paper both the volumetric displacement and the shaft speed of a variable displacement swash-plate type piston pump were varied in order to minimize power consumption in supplying constant-pressure oil to a valve-controlled hydraulic cylinder, particularly during idle modes. At operating modes which were launched by position command inputs, the pump speed was varied by a pressure control algorithm to maintain a constant system pressure, with the swash plate angle fixed at the maximum. At idle, with no position controller input signal and the system pressure greater than or equal to the reference value, the swash plate angle and pump speed were lowered to their minimum limits. Computer simulation and experimental results showed that the idling power could be reduced by up to 83% by reducing the pump speed from 1800 rpm to 300 rpm and the swash plate angle to 3A degrees, compared to a conventional system consisting of a pressure-compensated variable displacement type pump driven at a constant speed of 1800 rpm.

关键词： Artificial incubation   conservation   Dermochelys coriacea   Dominican Republic   hatching success   DERMOCHELYS-CORIACEA   SEX-RATIO   HATCHING SUCCESS   CHELONIA-MYDAS   GREEN TURTLES   EGGS   CONSEQUENCES   TEMPERATURE   HATCHLINGS   RELOCATION  

摘要： The beaches of Jaragua National Park in the Dominican Republic are the country's last known major nesting site for the leatherback marine turtle Dermochelys coriacea. This nesting aggregation is threatened by widespread illegal egg take, and clutch relocation and artificial incubation have been carried out as protection measures since 1974. We assess the efficacy of such efforts and investigate how artificial incubation may be influencing the success and sex ratios of clutches. We compare hatching success, incubation duration and embryo mortality in in-situ clutches (n = 43) with those incubated artificially at sites in the east and west of the Park (n = 35 and n = 31, respectively). Our results show that in the west, artificial incubation significantly decreases hatching success in clutches. In the east the duration of incubation is increased, which we predict would result in an increase in the number of males from these clutches. Clutch relocation is currently the only viable conservation option for clutches on eastern beaches because of illegal egg take but action is needed to ensure that the natural sex ratio is not distorted. However, on the western beaches in situ clutch incubation seems possible through beach protection. Further community engagement and enforcement are required to improve conservation measures at eastern beaches if long-term, less sustainable intervention is to be avoided.

关键词： Apoptosis   CCL21,CD127, CD8+T cell   Diabetes   Free radicals   IFN-alpha/beta   Spleen   MICE LACKING EXPRESSION   CD4 T-CELLS   INTERLEUKIN-7 RECEPTOR   INTERFERON-ALPHA   NOD MICE   HOMEOSTATIC PROLIFERATION   BETA-CELLS   B-CELLS   IL-7   CHEMOKINE  

摘要： Type 1 diabetes mellitus (T1D) is associated with increased type 1 interferon (IFN) levels and subsequent severe defects in lymphocyte function, which increase susceptibility to infections. The blockade of type 1 IFN receptor 1 (IFNAR1) in non-obese diabetic mice has been shown to delay T1D onset and decrease T1D incidence by enhancing spleen CD4+ T cells and restoring B cell function. However, the effect of type 1 IFN blockade during T1D on splenic CD8+ T cells has not previously been studied. Therefore, we investigated, for the first time, the effect of IFNAR1 blockade on the survival and architecture of spleen-homing CD8+ T cells in a streptozotocin-induced T1D mouse model. Three groups of mice were examined: a non-diabetic control group; a diabetic group; and a diabetic group treated with an anti-IFNAR1 blocking antibody. We observed that T1D induction was accompanied by a marked destruction of beta cells followed by a marked reduction in insulin levels and increased IFN-alpha and IFN-beta levels in the diabetic group. The diabetic mice also exhibited many abnormal changes including an elevation in blood and spleen free radical (reactive oxygen species and nitric oxide) and pro-inflammatory cytokine (IL-6 and TNF-alpha) levels, a significant decrease in IL-7 levels, and subsequently, a significant decrease in the numbers of spleen-homing CD8+ T cells. This decrease in spleen-homing CD8+ T cells resulted from a marked reduction in the CCL21-mediated entry of CD8+ T cells into the spleen and from increased apoptosis due to a marked reduction in IL-7-mediated STAT5 and AKT phosphotylation. Interestingly, type 1 IFN signaling blockade in diabetic mice significantly restored the numbers of splenic CD8+ T cells by restoring free radical, proinflammatory cytoldne and IL-7 levels. These effects subsequently rescued splenic CD8+ T cells from apoptosis through a mechanism that was dependent upon CCL21- and IL-7-mediated signaling. Our data suggest that type 1 IFN is an es

关键词： Torsional systems   Transient vibration amplification   Time-frequency domain methods   Non-stationary process   Harmonic balance method   FREQUENCY-RESPONSE CHARACTERISTICS   TORSIONAL SYSTEM   DYNAMIC-ANALYSIS   GEAR RATTLE   INTEGRATION   EXCITATION   NVH  

摘要： The transient vibration phenomenon in a vehicle powertrain system during the start-up (or shut-down) process is studied with a focus on the nonlinear characteristics of a multi-staged clutch damper. First, a four-degree-of-freedom torsional model with multiple discontinuous nonlinearities under flywheel motion input is developed, and the powertrain transient event is validated with a vehicle start-up experiment. Second, the role of the nonlinear torsional path on the transient event is investigated in the time and time frequency domains; interactions between the clutch damper and the transmission transients are estimated by using two metrics. Third, the harmonic balance method is applied to examine the nonlinear characteristics of clutch damper during a slowly varying non-stationary process in a simplified and validated single-degree-of-freedom powertrain system model. Finally, analytical formulas are successfully developed and verified to approximate the nonlinear amplification level for a rapidly varying process. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： MOVING VISCOELASTIC BEAMS   NONLINEAR DYNAMICS   PARAMETRIC RESONANCE   MODAL-ANALYSIS   VIBRATION   TRANSIENT   DRIVES  

摘要： The stable steady-state periodic response of a two-pulley belt drive system coupled with an accessory by a one-way clutch is presented. For the first time, the pulley belt system is studied under double excitations. Specifically, the dual excitations consist of harmonic motion of the driving pulley and inertia excitation. The belt spans are modeled as axially moving viscoelastic beams by considering belt bending stiffness. Therefore, integro-partial-differential equations are derived for governing the transverse vibrations of the belt spans. Moreover, the transverse vibrations of the moving belt are coupled with the rotation vibrations of the pulleys by nonlinear dynamic tension. For describing the unidirectional decoupling function of the one-way device, rotation vibrations of the driven pulley and accessory are modeled as coupled piecewise ordinary differential equations. In order to eliminate the influence of the boundary of the belt spans, the non-trivial equilibriums of the pulley - belt system are numerically determined. Furthermore, A nonlinear piecewise discrete-continuous dynamical system is derived by introducing a coordinate transform. Coupled vibrations of the pulley belt system are investigated via the Galerkin truncation. The natural frequencies of the coupled vibrations are obtained by using the fast Fourier transform. Moreover, frequency response curves are abstracted from time histories. Therefore, resonance areas of the belt spans, the driven pulley and the accessory are presented. Furthermore, validity of the Galerkin method is examined by comparing with the differential and integral quadrature methods (DQM & IQM). By comparing the results with and without one-way device, significant damping effect of clutch on the dynamic response is discovered. Furthermore, the effects of the intensity of the driving pulley excitation and the inertia excitation are studied. Moreover, numerical results demonstrate that the two excitations interact on the steady-s

关键词： 车辆离合器   局部高温区   热弹性不稳定性   临界速度  

摘要： 车辆离合器失效,主要原因是摩擦副表面的局部高温,而摩擦副表面出现局部高温的原因主要来源于车辆离合器在接合过程中出现的热弹性不稳定性。所以要讨论车辆离合器局部高温区产生的原因及其影响因素,首先要分析何为热弹性不稳定理论,在什么情况下会导致系统进入特弹性不稳定状态,进而才能弄清楚在热弹性不稳定状态下如何出现离合器局部高温区及其影响因素。本文就热弹性不稳定理论展开探讨。

关键词： Internal Combustion Engine   Continuous Variable Transmission   Installation Space   Input Shaft   Versus Hybrid  

关键词： 数值模型   粗糙接合   渗透率   油槽湿式离合器   摩擦材料  

摘要： 已经开发了粗糙可渗透带油槽的湿式离合器接合的模型,用于确定不同输入参数(作用负荷、油槽面积和摩擦材料的可渗透率)对接合过程的影响。该模型关于表面粗糙度的影响按照Patir和Cheng(1978),其摩擦材料的渗透率按照Natsumeda及Miyoshi(1994)和Beavar及Josph(1967),带油槽的摩擦材料按照最近的逼近方法。该方法简化了雷诺和对油膜厚度和时间的一次一阶差分方程的力平衡方程式。一线性的搜索算法。采用对新模型函数计算的低的计算费用用来求得相同接合特性的一组输入参数组合。作为在该参数空间(Fapp,^Φred)内接合等面描述为这样的设计点组合,该等面无疑给出有关接合时间和表示不可能实现所期望的接合特性的区间的有关数据。输入参数分为接合瞬变部分的影响和稳态部分的影响二类。

关键词： 湿式离合器   Matlab   混合编程   图像处理  

摘要： 从实际需求出发,根据VC++和Matlab的各自特性,在湿式离合器内外径测量中使用VC++和Matlab技术。首先论述VC++和Matlab混合编程的配置及优势,然后详细阐述,如何使用Matlab图像处理函数库计算湿式离合器内外径的大小。