Results 21 to 30 of about 56,695 (159)
Model Motion Control Simulation and Implementation of WDPSS Support in Wind Tunnel Test [PDF]
, 2015 摘要 绳牵引并联机构WDPSS是一种新型低速风洞试验的模型支撑系统，其因灵活度高、模型支撑刚度大、对流场干扰小等诸多优点而逐渐被认识和认可。本文针对该机构进行了运动控制的建模与仿真，根据风洞试验的要求开发了控制系统相关功能模块，并对视觉系统采集信号进行了有效滤波，为将WDPSS的工程应用奠定了基础。本文完成的研究工作与成果如下所述。 首先，针对WDPSS-8原理样机，进行了运动学与动力学分析。通过运动学逆解分析得出绳长与飞机模型位姿之间的关系，根据驱动系统结构特点建立其动力学模型，利用牛顿 ...
王义龙
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International Journal of Applied Linguistics, EarlyView.ABSTRACT Although the use of AI technologies (e.g., chatbots and automated writing evaluations (AWE)) has gained considerable attention in language learning fields in recent years, how AI technologies have been designed and implemented in language learning education, as well as their effectiveness, is understudied.
Shen Qiao +2 more
wiley +1 more source
Electric Hot Assisted Turning and Its Process Monitoring [PDF]
, 2015 近年来，机械加工行业中出现了大量耐高温、强度高、硬度大的难加工材料。在这些材料的加工过程中，普遍存在着切削力大、刀具磨损严重、表面质量差等问题。用常规的刀具材料和加工方法很难进行切削加工，也达不到现代工业技术的要求。随着历史的发展，人们提出了许多针对这些难加工材料的加工思路和方法，加热切削就是比较好的思路，而导电加热切削则是其中一种行之有效的方法。 本文对现有导电加热切削技术做出了一些研究，提出了通电加热辅助车削的方法，意在探寻这种方法的可行性和效果。通电加热辅助车削是把低压大电流通入到由电源 ...
张天宇
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The Development and Validation of the Chinese Vocabulary Levels Test
International Journal of Applied Linguistics, EarlyView.ABSTRACT In response to the increasing need for effective Chinese vocabulary assessments, this study developed the Chinese Vocabulary Levels Test (CVLT), a test designed for intermediate‐level Chinese as a second or foreign language (CSL/FL) learners, based on the vocabulary lists (levels 4–6) from the Chinese Proficiency Grading Standards for ...
Shiwei Qi, Ailan Fu
wiley +1 more source
, 2012 [目的]研究十字花科与豆科作物对微囊藻毒素(MC)耐受性的差异。[方法]以十字花科作物典型作物油菜、小白菜、甘蓝与豆科典型作物黄豆、豌豆、蚕豆为材料,检测它们在不同浓度MC暴露条件下的生长发育情况,检测指标包括发芽率、株高、叶绿素等。[结果]十字花科作物中油菜与小白菜受MC影响较大,甘蓝受影响较小,而豆科作物普遍受影不大。[结论]豆科作物比十字花科作物对MC耐受性更强 ...
刘剑彤, 刘碧波, 吴烨
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International Journal of Applied Linguistics, EarlyView.ABSTRACT Collaborative writing has attracted increasing attention in English as a Foreign Language (EFL) instruction due to its potential to enhance learners’ writing competence. However, few studies have examined the comparative effects of collaborative versus independent writing on EFL learners’ individual performance, especially in higher‐order ...
Ting Huang, Chenze Wu, Wenkang Zhang
wiley +1 more source
苏联对纳粹德国火箭技术的争夺(1944~1945) [PDF]
, 2013 第二次世界大战末期,苏联先后夺取纳粹德国设置在波兰和本土的火箭基地,部分地分享到德国的火箭产品、仪器、设备设施、资料和技术专家等,掌握了一些关键核心技术,进而筹划仿制V-2火箭。这次技术转移提高了苏联的技术起点,缩短了苏联研发火箭武器的时间,为后来的技术创新打下了基础。经对俄文档案、回忆录及其他文献的研读,本文初步梳理苏联争夺德国弹道导弹技术的历程 ...
王芳
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Basic income trials and the politics of scale: A research agenda
Policy Studies Journal, EarlyView.Abstract The growing popularity of basic income has led to extensive trials of the policy in numerous settings across the world. However, analysis of the politics of basic income, and in particular the political dynamics preceding and resulting from trial programs, lags. In response, we propose a research agenda that uses political scale to investigate
Jurgen De Wispelaere +2 more
wiley +1 more source
Dianci bileiqi, 1986 本文叙述了RXQ型电压互感器消谐器的保护原理。此消谐器既能消除中性点不接地系统中由电压互感器(PT)的非线性励磁特性所引起的过电压,又能抑制由弧光接地所引起的流过PT的过电流,进而防止了PT的烧毁。文中提出了与经典理论不同的谐振范围曲线,论证了消谐器的参数与技术要求,介绍了运行情况,并与国内数种消谐器作了有关比较。
1.西北电力试验研究所 +2 more
doaj
Simulation Analysis and Optimization of Coach Seat and Passenger Coupling Impact System [PDF]
, 2015 据相关资料表明，在客车碰撞所造成的人员伤亡中，因乘员与座椅之间的二次碰撞或座椅与车体相连部位的失效占了相当大的比例。为了提高我国客车在碰撞事故中对乘员的保护能力，客车座椅及其固定点强度的国家标准GB13057-2014目前已从推荐性标准升级为强制性实施标准。为了保证所设计的座椅能满足新法规要求，必须深入研究客车座椅及其固定支架的结构变形及乘员在碰撞过程中的伤害情况。 汽车碰撞过程是一个瞬间的复杂的物理变形过程，它包含了几何非线性，材料弹塑性变形非线性和零部件间复杂的接触非线性等特征 ...
卢琳兆
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