关键词： 机械式   变速器   混合动力  

摘要： 随着汽车日益的增长,柴汽油为动力的客车尾气的排放造成环境空气逐渐的恶化,现在以电机和电池为动力的混合动力客车在我国的市场很受欢迎它与传统柴、汽油为动力的客车有了很大的区别,本文主要研究混合动力客车机械式自动变速器参数的设计和优化,在保证车辆动力性能良好的前提下优化动力的参数,使其具有更好的经济性、环保性.

关键词： 步态模拟   足部模型   动力学仿真   生物力学   地面反作用力  

摘要： 本文旨在建立适用于步态动力学仿真分析的足部分块模型并验证其有效性及实用性。本文基于新型的混合驱动人体步态试验机,将骨骼模型导入机械系统动力学自动分析软件(ADAMS)中,结合在其中建立的足部韧带、筋膜、肌肉模型及柔性体足底软组织模型,组成足部分块模型。用在体试验采集到的步态数据作为驱动,并在模型上加载肌肉力和肌腱力,进行步态模拟。将得到的地面反作用力及关节旋转角度与报道结果进行比较,验证了模型的有效性。本文仿真结果表明,本模型能较好地用于步态动力学仿真分析,并有望作为进一步研究的工具。

关键词： 凸轮   机械变磁通   机械系统动力学自动分析   错开角度   弱磁能力  

摘要： 对机械变磁通轴向磁场永磁电机（MVFAFPMEM）进行机械动力学与电磁场仿真分析,研究机械调磁装置的运动特性、角度调节能力及电机弱磁能力。基于机械系统动力学自动分析（ADAMS）虚拟样机技术,研究了不同转速下凸轮角加速度和弹簧形变情况,获得了转子错开角度随电机转速的变化规律;利用有限元方法计算了转子错开角度变化时的电机气隙磁场,研究了凸轮式机械调磁装置对电磁特性的影响。仿真结果表明,利用所设计的调磁装置,可使电机两转子间的错开角度在0°-21°范围内变化,弱磁能力较强。试验结果验证了理论与仿真分析的正确性,利用凸轮式机械调磁装置能够根据电机转速自动调节两转子间的相对位置,实现轴向磁场永磁电机气隙磁场强度的宽范围调节。

关键词： 农业机械   劳动力   投入产出弹性   技术替代弹性  

摘要： 随着中国城镇化进程的不断推进和农村劳动力大量外出转移,中国农业生产正在朝着依靠更多机械投入的方向发展。认清农业机械对劳动力替代强度和粮食产出的影响以及这种影响在不同粮食品种、不同时空上的差异至关重要。本文基于全国农村固定观察点2003~2014年的农户面板数据,利用超越对数生产函数对机械和劳动力投入产出弹性以及两者间的技术替代弹性进行了测算。研究结果表明,农业机械的发展有效地替代了农业劳动力并促进了粮食产量的增加,但农业机械对劳动力替代强度在不同粮食之间表现出时空差异性。具体而言,从2003到2014年,全国小麦、稻谷的“机械—劳动力”技术替代弹性值恒为正,形成了农业机械对劳动力的替代,玉米的“机械—劳动力”技术替代弹性值从-0.744升至0.101,机械和劳动力关系经历了从互补向替代的衍变;全国农业机械对劳动力替代强度的比较上,稻谷高于小麦,小麦高于玉米;不同地区的比较上,平原地区农业机械对劳动力菅代强度要高于非平原地区。因此考虑到农业机械技术发展水平在不同地区和粮食品种上的差异,今后农业机械技术创新与推进重点在结构上应该更多地向玉米和非平原地区倾斜。

关键词： 铁路机务系统   机械动力设备   优化管理  

摘要： 时代的进步给铁路带来了较大的发展,很多新型的设备与工艺不断被应用到铁路的实际运营过程之中,但这种情况就对铁路机务系统机械动力设备的管理提出了新的要求,相关单位与工作人员要对机械动力设备的管理工作水平进行不断提升,以此来保证铁路部门的经济效益与工作效率^([1])。在此背景之下,本文对铁路机务系统机械动力设备管理工作的优化进行了一些分析与探讨。

关键词： 电子机械制动   simulink   动力学模型   制动性能  

摘要： 研究汽车电子机械制动系统制动性能是新能源电动汽车面临的新课题,以特定车型满载运行工况为对象,基于simulink软件建立了整车、轮胎和制动系统的动力学模型,完成了制动性能分析,验证了抱死拖滑的制动效果及其影响,得到了制动减速度变化、制动距离和附着系数值等制动效能参数;分析结果表明,该制动系统性能稳定。

关键词： Semi-IPN   PHEMA   PLLA  

摘要： Semi-interpenetrating polymer networks (semi-IPNs) have attracted much attention in recent years as biomaterials with a high potential in tissue engineering and controlled drug release. In this article, semi-IPNs were synthetized by free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) in the presence of poly(L-lactic acid) (PLLA) with contents of 5,10 and 20 wt.% at high temperature (150 degrees C). The study focused on the analysis of thermal and mechanical properties, wettability, swelling kinetics in buffered solutions of different pH, and biocompatibility using fibroblasts of human embryonic skin. Segregation of the components in different microdomains was verified by morphological analysis through scanning electron microscopy (SEM). Differential scanning calorimetry (DSC) results revealed that the poly(2-hydroxyethyl methacrylate) (PHEMA) network is amorphous and the PLLA is semi-crystalline. Mechanical analysis provided Young's modulus values in the range 240-370 MPa in tensile tests, and storage modulus (E') values at 37 degrees C, 1 Hz, in the range 800-1200 MPa. Equilibrium water uptake measurements displayed material dependence on composition and pH. Swelling kinetics presented good agreement with a second-order diffusion process in all media. No sample present cytotoxicity and the cell migration process occupied many semi-IPNs pores closing them and indicating good cellular recognition. In overall, these networks can be considered for their application as scaffolds for bone defects augmentation and subchondral cartilage repair. (C) 2016 Published by Elsevier Ltd.

关键词： Thermo-mechanical processes   Constitutive model   Thermodynamics   Clay  

摘要： The thermo-mechanical (T-M) coupling behavior of clay can be difficult to predict due to its complicated coupling mechanism, irreversibility and OCR dependency. To date, several constitutive models were proposed based on the phenomenological theory of elasticity and plasticity, which are able to simulate some of the T-M coupling behavior but lacks the fundamental description of coupling dissipation mechanism. The theory of Granular Solid Hydrodynamics (GSH) originally developed for single phase and isothermal granular solid has provided an alternative framework for the constitutive modeling of granular geomaterials. This paper first introduces the T-M coupled fundamental behavior of clay and its existing constitutive models. Then a constitutive model of a single phase and isothermal granular solid based on GSH is briefly outlined, followed by an extension of this GSH-based model made to account for a cohesive saturated granular solid, e.g. clay subjected to non-isothermal loading conditions. Based on the extension of GSH, a T-M coupled constitutive model is established, which allows for a better understanding of the physical mechanism underlying the observed T-M coupled behavior of clay. Verification of the model is conducted by predicting the thermally induced volumetric deformation and the undrained thermal failure of saturated Kaolin clay and Boom clay. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Slags  

摘要： The kinetics of aluminum removal from silicon melt to CaO-SiO2-Al2O3 slag was studied. A recently designed experimental setup using mechanical stirring was employed to focus the study on the chemical reaction. The slag and metal were found to reach chemical equilibrium in 300 seconds. A simple model could reproduce the experimental data satisfactorily. Both the experimental results and the model prediction further confirmed that the process was controlled by the chemical reaction, since the reaction rate constant was found to be independent of the amount of slag and the initial slag composition. The experimental data at equilibrium were compared with the model calculations. The discrepancy between the model calculations and the experimental data strongly suggests the need for careful thermodynamic measurements. (C) The Author(s) 2016. This article is published with open access at ***

关键词： Microalgae   Biomass   Biofuels   Modelling   Photobioreactor  

摘要： Various innovative photobioreactor designs have been proposed to increase production of algae-derived biomass. Computer models are often employed to test these designs prior to construction. In the drive to optimise conversion of light energy to biomass, efforts to model the profile of irradiance levels within a microalgal culture can lead to highly complex descriptions which are computationally demanding. However, there is a risk that this effort is wasted if such optic models are coupled to overly simplified descriptions of algal physiology. Here we demonstrate that a suitable description of microalgal physiology is of primary significance for modelling algal production in photobioreactors. For the first time, we combine a new and computationally inexpensive model of irradiance to a mechanistic description of algal growth and test its applicability to modelling biofuel production in an advanced photobioreactor system. We confirm the adequacy of our approach by comparing the predictions of the model against published experimental data collected over a 2 A 1/2 -year period and demonstrate the effectiveness of the mechanistic model in predicting long-term production rates of bulk biomass and biofuel feedstock components at a commercially relevant scale. Our results suggest that much of the detail captured in more complicated irradiance models is indeed wasted as the critical limiting procedure is the physiological description of the conversion of light energy to biomass.