Assessment of motion of a swing leg and gait rehabilitation with a gravity balancing exoskeleton.

The gravity balancing exoskeleton, designed at University of Delaware, Newark, consists of rigid links, joints and springs, which are adjustable to the geometry and inertia of the leg of a human subject wearing it. This passive exoskeleton does not use any motors but is designed to unload the human leg joints from the gravity load over its range-of-motion. The underlying principle of gravity balancing is to make the potential energy of the combined leg-machine system invariant with configuration of the leg. Additionally, parameters of the exoskeleton can be changed to achieve a prescribed level of gravity assistance, from 0% to 100%. The goal of the results reported in this paper is to provide preliminary quantitative assessment of the changes in kinematics and kinetics of the walking gait when a human subject wears such an exoskeleton. The data on kinematics and kinetics were collected on four healthy and three stroke patients who wore this exoskeleton. These data were computed from the joint encoders and interface torque sensors mounted on the exoskeleton. This exoskeleton was also recently used for a six-week training of a chronic stroke patient, where the gravity assistance was progressively reduced from 100% to 0%. The results show a significant improvement in gait of the stroke patient in terms of range-of-motion of the hip and knee, weight bearing on the hemiparetic leg, and speed of walking. Currently, training studies are underway to assess the long-term effects of such a device on gait rehabilitation of hemiparetic stroke patients.     

微量元素及控轧控冷工艺对非调质钢40MnV冲击性能的影响

通过在40MnV钢中控制微量元素含量并控制热加工工艺，探讨提高非调质钢冲击性能的方法。     

高档白兰地葡萄的发酵过程

研究了高档白兰地所用葡萄在发酵过程中的变化,分别对相同产区不同葡萄品种、不同产区相同葡萄品种、不同的葡萄前加工方式、不同的葡萄发酵控制条件进行对比观察,利用气质联仪(GC-MS)详细分析发酵前后的理化指标变化。对发酵前后的样品进行感官评定,结合分析结果得出高档白兰地用葡萄的最佳发酵参数。     

新时代中国外交翻译及其形象构建研究

国家形象影响民族凝聚力与归属感,决定国家地位。外交翻译作为国家形象输出的重要载体,采取何种翻译方法也是一个不可回避的问题。本文拟从形象学出发,探究新时代中国国家形象构建下外交翻译的特点及走势,指出了新时代形象构建下我国外交翻译具有政治意识、受众意识、文化自觉等主要特点,进行总结分析,以更好地认识外交翻译存在的问题。     

Generation of simultaneous H+ and He+ band EMIC waves in the nightside radiation belt

Science China Technological Sciences - Previous studies have shown that EMIC waves occur preferentially in the afternoon sector of the magnetosphere. Here we report obliquely propagating H+ and He+...     

风机中参数变化对变流器直流侧电容可靠性的影响分析

以风电机组功率变流器可靠性评估为背景,给出了一种直流侧电容的可靠性评估方法。基于电容的损耗计算方法,结合热网络结构,构建了直流侧电容的可靠性分析流程。综合考虑电容的可靠性影响因素,分析了环境温度、风速、电容等效串联电阻及热阻的变化对直流侧电容可靠性的影响。以某风电场2 MW双馈风电机组结合实际风速、气温数据为例进行验证,实例结果验证了理论分析的正确性。讨论了当风电变流器实际工作时,利用优化变流器直流侧设计或电容的散热环境等措施提高直流侧电容的可靠性,结果表明了所提方案的可行性。     

Impact of Solvent Additive on Carrier Transport in Polymer:Fullerene Bulk Heterojunction Photovoltaic Cells

The effects of a solvent additive, 1,8‐diiodooctane (DIO), on both hole and electron transport are investigated in a state‐of‐the‐art bulk‐heterojunction (BHJ) system, namely PTB7:PC₇₁BM. For a polymer:fullerene weight ratio of 1:1.5, the electron mobility in the blend film increases by two orders of magnitude with the DIO concentration while almost no change is found in the hole mobility. For lower DIO concentrations, the electron mobility is suppressed because of large, but poorly connected PC₇₁BM domains. For higher concentrations of DIO, the electron mobility is improved progressively and the hole mobility becomes the limiting factor. Between 1 and 5 vol%, the electron and hole mobilities are balanced. Using the Gaussian disorder model (GDM), we found that the DIO concentration modifies fundamentally the average hopping distances of the electrons. In addition, there exist alternative donor–acceptor ratios to achieve optimized PTB7:PC₇₁BM based solar cells. It is demonstrated that the fullerene content of the BHJ film can be significantly reduced from 1:1.5 to 1:1 while the optimized performance can still be preserved.     

关于建筑工程造价预结算问题分析与探讨

本文主要就建筑工程造价预结算审核中的要点问题进行了深入探讨,分别对建筑工程设计变更单和施工签证单审核、工程量审核、单价套用审核、取费审核等审核内容进行了阐述,并提出了自己的一些观点,以供同行参考。