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关键词： 汽车   离合器   摩擦片   发展与应用  

摘要： 由于实际汽车行驶过程中,速度不稳定,再加上摩擦式离合器柔度高,能减少离合器结合过程中的冲击和振动,对其他的零件的损伤小,因而广泛应用于汽车制造领域。

关键词： 摩擦式离合器   性能分析   参数选取  

摘要： 摩擦式离合器是汽车传动系统中比较重要的一个零部件,主要控制传动系统的动力传动的通断控制。以别克君威2.0L轿车为例,根据整车性能及要求,按照相关标准,通过分析计算,选取其对应的离合器参数,为后续建模打下基础。

关键词： Clutch judder   engine torque excitation   harmonic order   nonlinear friction torque   torsional stiffness   TORSIONAL SYSTEM   DRY FRICTION   STICK-SLIP   VIBRATION   SIMULATION  

摘要： A simplified three-degree-of-freedom dynamic model with nonlinear friction torque and engine torque excitation, capable of identifying the effect of the engine excitation on clutch judder, is presented. The analysis of harmonic order is performed and a sinusoidal contact pressure between friction surfaces is considered, along with an analytical solution for the relative angular velocity of the clutch plates. The average fluctuation amplitude of the clutch relative angular velocity is used to evaluate the judder. Numerical calculations indicate that the clutch judder increases significantly when the angular velocity of the crankshaft, corresponding to the harmonic orders of the engine, is equal or close to the natural frequency of the driveline. An identical frequency of the engine excitation and the oil pressure fluctuation contributes little to the clutch judder, unless the excitation is at or near the resonance frequency. The amplitudes of oscillations due to the engine excitation grow when the pulsating torque of the engine increases. The mean torque of the engine has little influence on the judder, although it governs the clutch engagement time. The results further show that clutch judder attenuates as the torsional stiffness of the system increases.

关键词： Activation-induced cytidine deaminase   Hepatitis B virus   Co-inhibitory signal   Hydrodynamic injection   INDUCED CYTIDINE DEAMINASE   NF-KAPPA-B   VIRUS-INFECTION   PLASMID DNA   HUMAN HEPATOCYTES   IN-VIVO   TRANSGENE EXPRESSION   ANTIGEN   LIVER   MICE  

摘要： Hepatitis B virus (HBV) infection evokes host immune responses that primarily determine the outcome of HBV infection and the clinical features of HBV-associated liver disease. The precise mechanisms by which host factors restrict HBV replication, however, are poorly understood due to the lack of useful animal models that recapitulate immune responses to HBV. Here, we performed comprehensive immunologic gene expression profiling of the liver of a mouse model recapitulating anti-HBV immune response using a high sensitivity direct digital counting system. Anti-HBV cellular immunity with liver inflammation was elicited in mice hydrodynamically injected with a CpG-depleted plasmid encoding hepatitis B surface antigen (HBsAg) gene after preimmunization with HBsAg vaccine. Comprehensive expression analyses revealed the upregulation of Thl-associated genes including tumor necrosis factor (Tnf) and negative regulators of T cell function in the inflamed liver. Interestingly, activation-induced cytidine deaminase (Aicda, termed AID in humans), which reportedly suppresses HBV infection in vitro, was upregulated in hepatocytes in the course of anti-HBV immunity. Hepatocytic expression of Aicda in a Tnf-dependent manner was confirmed by the administration of Tnf antagonist into AicdatdTomato mice with anti-HBV immunity. Our findings suggest that activation of Tnf Aicda axis and co-inhibitory signals to T cells in coordination with Thl-type immunity has critical roles in the immune response against HBV infection.(C) 2017 Elsevier B.V. All rights reserved.

关键词： Earthquake early warning   MEMS-based accelerometer   High dynamic range   STA-LTA event detection   Low-latency data packet   P-PHASE PICKING   SOUTHERN CALIFORNIA   SYSTEM   NETWORK   SENSORS   CHINA   NOISE   RECORDINGS   TAIWAN  

摘要： Earthquake Early Warning System (EEWS) has shown its efficiency for earthquake damage mitigation. As the progress of low-cost Micro Electro Mechanical System (MEMS), many types of MEMS-based accelerometers have been developed and widely used in deploying large-scale, dense seismic networks for EEWS. However, the noise performance Of these commercially available MEMS is still insufficient for weak Seismic signals, leading to the large scatter of early-warning parameters estimation. In this study, we developed a new type of tri-axial accelerometer based on high dynamic range MEMS with low noise level using for EEWS. It is a MEMS-integrated data logger with built-in seismological processing. The device is built on a custom-tailored Linux 2.6.27 operating system and the method for automatic detecting seismic events is STA/LTA algorithms. When a seismic event is detected, peak ground parameters of all data components will be calculated at an interval of 1 s, and tc-Pa values will be evaluated using the initial 3 s of P wave. These values will then be organized as a trigger packet actively sent to the processing center for event combining detection. The output data of all three components are calibrated to sensitivity 500 counts/cm/s2. Several tests and a real field test deployment were performed to obtain the performances of this device. The results show that the dynamic range can reach 98 dB for the vertical component and 99 dB for the horizontal components, and majority of bias temperature coefficients are lower than 200 yg/ C. In addition, the results of event detection and real field deployment have shown its capabilities for EEWS and rapid intensity reporting.

关键词： Clutches (Machinery) -- Evaluation  

摘要： The article evaluates the Advantage Series heavy-duty clutches from Eaton Corp. PLC.

关键词： RISK-FACTORS   CRYSTALLINE LENS   PREVALENCE   THICKNESS   PROGRESSION   BIOMETRY   INDEX  

摘要： Purpose: To calculate crystalline lens power and to determine the relationship between ocular biometry and diabetic retinopathy (DR) in an adult population with type 2 diabetes mellitus (T2DM). Design: Cross-sectional, population-based study. Participants: Patients with T2DM from the Beixinjing community, Changning district, Shanghai. Methods: Random clustering sampling was used to identify adults with T2DM in the Beixinjing community. Spherical equivalent (SE) was determined by subjective refraction that achieved the best corrected vision. Axial length (AL), corneal power (CP), and anterior chamber depth (ACD) were measured using the IOLMaster. Diabetic retinopathy and diabetic macular edema (DME) were assessed according to the international DR classification. Main Outcome Measures: The crystalline lens power was calculated using the Bennette-Rabbetts formula. The AL-to-corneal radius ratio (AL/CR ratio) was defined as the axial length divided by the mean corneal radius of curvature. Results: A total of 4011 eyes of 2057 subjects with T2DM were included in the analysis. In multivariate logistic models adjusting for age, sex, duration of diabetes, glycosylated hemoglobin A1c, serum creatinine, body mass index, systolic blood pressure, and cataract, after categorizing values into quartiles, there were trend associations between lens power and any DR (P = 0.01), between AL/CR ratio and any DR (P = 0.02), and between AL and any DR (P = 0.03), between lens power and moderate DR (P = 0.02), and between AL and moderate DR (P = 0.02); eyes with higher AL/CR ratio were less likely to have any DR (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.24-0.78; P = 0.01 per 1 increase) and moderate DR (OR, 0.44; 95% CI, 0.21-0.93; P = 0.03 per 1 increase), eyes with longer AL were less likely to have any DR (OR, 0.88; 95% CI, 0.81-0.95; P = 0.002 per millimeter increase) or moderate DR (OR, 0.89; 95% CI, 0.80-0.98; P = 0.02 per millimeter increase), and eyes with higher SE we

关键词： Antioxidant capacity   Crested penguins   Female condition   Maternal transfer   Oxidative status   Stable isotope   LAYING-SEQUENCE VARIATION   BARN SWALLOW EGGS   ROCKHOPPER PENGUINS   OXIDATIVE STATUS   MATERNAL DEPOSITION   YOLK ANTIOXIDANTS   STEROID-HORMONES   TRADE-OFFS   FEMALE   CAROTENOIDS  

摘要： Oviparous females need to allocate resources optimally to their eggs in order to maximize their fitness. Among these resources, dietary antioxidants, acquired by females and transferred to the eggs during egg formation, can greatly affect the development and survival of the embryo and chick. In crested penguins, incubation starts after the second and last egg is laid and, as opposed to many other bird species, this egg hatches first, thereby enhancing the survival of the chick. Here, we assessed whether antioxidant and isotopic composition could underlie these differences between eggs within clutches of southern rockhopper penguins (Eudyptes cluysocome cluysocome). The second-laid egg had higher total antioxidant capacity than the first-laid egg, although this was not due to higher antioxidant concentration but to its higher mass. This suggests that resources are allocated by females at a constant rate in both eggs within clutches. Accordingly, we found a strong correlation for isotopic compositions between eggs suggesting that resources were allocated similarly to each egg within the clutch. Overall, we found little evidence for a significant role of antioxidant and isotopic compositions to explain differences in terms of embryo/chick development between eggs in crested penguins. However, since our results suggest a constant rate of antioxidant transfer from females to eggs, limiting the mass of the first-laid egg might represent a strategy for females to spare antioxidant defences and preserve self-maintenance. (C) 2017 Elsevier Inc. All rights reserved.

关键词： Electric vehicle   Powertrain   Dual clutch transmission   Shift control   SIMULATION   SYNCHRONIZATION   OPTIMIZATION   SYSTEM   TORQUE   MOTOR  

摘要： The purpose of this paper is to demonstrate the application of torque based powertrain control for multi-speed power shifting capable electric vehicles. To do so simulation and experimental studies of the shift transient behaviour of dual clutch transmission equipped electric vehicle powertrains is undertaken. To that end a series of power-on and power-off shift control strategies are then developed for both up and down gear shifts, taking note of the friction load requirements to maintain positive driving load for power-on shifting. A mathematical model of an electric vehicle powertrain is developed including a DC equivalent circuit model for the electric machine and multi-body dynamic model of the powertrain system is then developed and integrated with a hydraulic clutch control system model. Integral control of the powertrain is then performed through simulations on the develop powertrain system model for each of the four shift cases. These simulation results are then replicated on a full scale powertrain test rig. To evaluate the performance of results shift duration and vehicle jerk are used as metrics to demonstrate that the presented strategies are effective for shift control in electric vehicles. Qualitative comparison of both theoretical and experimental results demonstrates reasonable agreement between simulated and experimental outcomes. (C) 2016 Elsevier Ltd. All rights reserved.