共查询到20条相似文献，搜索用时 125 毫秒
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吴翠娥 《中国科教创新导刊》2013,(34):204-205
通过对孙雅薇和吴水娇两位优秀1 0 0米栏运动员跨栏步运动学特征的分析对比,发现她们的优缺点,为我国女子1 0 0米栏科学训练提供参考.分析运动员攻栏距离、下栏距离、跨栏距离、过栏时间、攻栏时起跨腿支撑时间、下栏后摆动腿支撑时间、栏间第一步的时间以及下栏落地支撑时起跨腿姿势等运动学参数.两位运动员基本符合了现代“远起跨,近下栏”的技术特征.（1）孙雅薇与世界优秀选手比较接近,吴水娇下栏距离还稍远.（2）孙雅薇过栏时间快于吴水娇,达到了世界优秀选手的水平.（3）孙雅薇攻栏时起跨腿支撑时间和下栏后摆动腿支撑时间均长于吴水娇.（4）从摆动腿着地瞬间身体姿势可看出,吴水娇的起跨腿已经摆至身体前方,而孙雅薇的起跨腿仍在体侧,其起跨腿的快速提拉不如吴水娇.（5）孙雅薇栏间第一步时间明显大于吴水娇.孙雅薇的过栏技术优于吴水娇,但“跨跑”的衔接技术不如吴水娇. 相似文献
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计算机在多栏帐中的应用任晓红多栏帐是常见的一种帐簿形式。在手工操作方式下,企业最常见的多栏帐是“管理费用”、“经营费用”、“生产成本”、“应交增值税”等多栏帐。应用多栏帐可较详细而全面地反映各个收支项目的增减变化情况,对比性较强,尤其在会计明细帐核算... 相似文献
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《赣南师范学院学报》1986,(Z1)
<正> 本文试图介绍一种简明的光栏概念的讲解方法,以照相机的瓣形光圈为例,同时直接从一般主轴上物点成象出发,阐明孔经光栏在光学仪器中的作用。从而得出孔径光栏的确定方法。 光栏是光学仪器中常用的重要光学元件,在教学中,将在光学仪器的聚光本领以及分辨本领的讲授中都需要用到光栏的概念。然而,它又是同学中难以理解的概念,其关键在于入射光瞳与孔径光栏关系的理解。其中,孔径光栏对成象光束的控制作用及成象光束最大孔径 相似文献
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为提高下栏着地技术教学的针对性,本文采用文献资料法、二维摄像法、影像解析法,对体教专业学生110米栏的下栏着地技术进行分析。研究发现:初学者上体躯干前倾幅度小,身体重心前移不够;栏上腾空时间长,下栏着地点远,着地角小,着地制动明显;摆动腿着地方式不正确,踝关节支撑能力差,着地缓冲时间过长,蹬伸不充分,衔接栏间跑的能力较差。 相似文献
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黄鑫 《赤峰学院学报(自然科学版)》2011,(7):193-195
跨栏跑是一项技术复杂、锻炼价值极高、对身体素质要求较高、节奏性强的运动项目.过栏技术是跨栏跑的关键环节,在过栏中,其动作正确与否将直接影响过栏动作的质量.本文运用相关理论并结合实际训练对攻栏、过栏、下栏过程中易出现的错误动作进行简要分析. 相似文献
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一、速算器图解二、速算器的原理、特点和作用原理是:“数珠”与数字一一对应。特点是:直观性强,使用简单,学生易接受并能操作;计算速度快,强于传统的数小棒,且结果准确无误。作用是:既可作教具,也可作学具,指导低年级学生数数和计算20以内的加减法。三、例析例1 4+4=8 操作过程:①先将数珠全部集中在下栏铁丝上;②从下栏数珠中拨4颗到上栏,使最后一颗数珠对齐上木方数字“4”;(这是第一个加数,见图1)③再从下栏数珠中拨4颗到上栏,使尾珠正好对齐上木方数字“8”,于是得到“4+4=8”。 相似文献
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为提高下栏着地技术教学的针对性,本文采用文献资料法、二维摄像法、影像解析法,对体教专业学生110米栏的下栏着地技术进行分析.研究发现:初学者上体躯干前倾幅度小,身体重心前移不够;栏上腾空时间长,下栏着地点远,着地角小,着地制动明显;摆动腿着地方式不正确,踝关节支撑能力差,着地缓冲时间过长,蹬伸不充分,衔接栏间跑的能力较差. 相似文献
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In order to constitute engineering design methods of the flat ribbon wound explosion containment vessels, the dynamic response of such vessels subjected to internal explosion loading is simulated using LS-DYNA3D. Three winding angles, 10°, 15°and 20°, are considered. It is shown that among ribbon vessels investigated, the center displacement of outermost ribbons of the vessel with 10°winding angle is the smallest under the same blast loading. The response of vessels loaded in inner core is local. From the center of the cylindrical shell to the bottom cover, the maximum strain gradually decreases. The ribbons are subjected to tension in the length direction and compression in the width direction. Blasting shock energy concentrates on where is close to center section of blasting. For comparison, numerical simulation of a monobloc thick-walled explosion containment vessel is also investigated. It can be found that the biggest deformation of the flat ribbon wound explosion containment vessels is bigger than that of the monobloc thick-walled explosion containment vessel in the center section of blasting under the same TNT. Numerical results are approximately in agreement with experimental ones. It is proved that the ribbon vessels have the valuable properties of " leak before burst at worst" compared with the monobloc vessels through numerical simulation. 相似文献
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An experimental and numerical investigation on the aeroengine blade/case containment analysis is presented. Blade out containment
capability analysis is an essential step in the new aeroengine design, but containment tests are time-consuming and incur
significant costs; thus, developing a short-period and low-cost numerical method is warranted. Using explicit nonlinear dynamic
finite element analysis software, the present study numerically investigated the high-speed impact process for simulated blade
containment tests which were carried out on high-speed spin testing facility. A number of simulations were conducted using
finite element models with different mesh sizes and different values of both the contact penalty factor and the friction coefficient.
Detailed comparisons between the experimental and numerical results reveal that the mesh size and the friction coefficient
have a considerable impact on the results produced. It is shown that a finer mesh will predict lower containment capability
of the case, which is closer to the test data. A larger value of the friction coefficient also predicts lower containment
capability. However, the contact penalty factor has little effect on the simulation results if it is large enough to avoid
false penetration. 相似文献
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Six-month-old infants' ability to form an abstract category of containment was examined using a standard infant categorization task. Infants were habituated to 4 pairs of objects in a containment relation. Following habituation, infants were tested with a novel example of the familiar containment relation and an example of an unfamiliar relation. Results indicate that infants look reliably longer at the unfamiliar versus familiar relation, indicating that they can form a categorical representation of containment. A second experiment demonstrated that infants do not rely on object occlusion to discriminate containment from a support or a behind spatial relation. Together, the results indicate that by 6 months, infants can recognize a containment relation from different angles and across different pairs of objects. 相似文献
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克林顿政府与中美关系的演变 总被引：1，自引：0，他引：1
刘建 《内蒙古大学学报(人文社会科学版)》2001,33(1):103-108
克林顿政府执政初期 ,由于对中国情况不了解 ,以及受大选政治和国内反华势力的影响 ,对华实行“遏制”与“接触”政策 ,不断在人权、贸易、台湾和军售等问题上制造事端 ,使中美关系一直走下坡路 ,并降到中美建交以来的最低点。进入第二任期后 ,克林顿随着个人地位的巩固和政治外交上的成熟 ,在对华政策上所受干扰和压力减少 ,能以务实的态度来处理中美关系 ,对对华政策做出调整 ,用全面接触政策替代了孤立遏制政策 ,从此中美关系进入了较成熟稳定发展的新时期 相似文献
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郭国伟 《江西电力职业技术学院学报》2009,22(4)
100kV文东线由于热缩套下的环绕防水带绕包不足,导致热缩套防水带和电缆本体缺乏良好压接,水份侵入电缆接头保护壳内造成外护套绝缘电阻不合格。 相似文献
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曹丹 《齐齐哈尔师范高等专科学校学报》2011,(6):45-46
长篇小说《曼斯菲尔德庄园》是英国女作家简.奥斯丁的的第四部作品,是其最有抱负,最富于思想性的作品。本文从新历史主义批评出发,通过分析《曼斯菲尔德庄园》中几位年轻女性的自我意识在各种力量＂协和＂作用下的形成过程,展现文学对人性的本质认识。主要采用＂颠覆＂和＂抑制＂两个概念展开分析。 相似文献
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Containment of high-speed rotating disk fragments 总被引：3，自引：0，他引：3
Disk burst accidents sometimes happen in aeroengines. To avoid tragic consequences, aeroengine casings must have sufficient containment capability. Experiments and simulations need to be conducted to study the impact, distortion, and perforation caused by disk burst and which may give important clues to potential failure mechanisms. This paper presents some containment tests of high-speed rotating disk fragments, in which the original disks were burst into three equal fragments within a predetermined rotating speed range. The failure modes of the containment casing varied significantly with the thickness of the containment casing. Shearing, tearing, tensile fracture, and large plastic stretching deformation occurred in a thin-walled containment casing, while a thick-walled casing could contain disk fragments and withstand large plastic deformation. Numerical simulations were carried out to study the impact process and failure modes further. Good agreement was found between the results of the simulations and the tests. 相似文献
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大学生犯罪是目前存在的一个很严重的社会问题。本文就大学生犯罪心理进行分析,阐述了犯罪心理的表现、诱因、自我调适和预防措施,以期对当前大学生犯罪的遏制有所裨益。 相似文献
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Strain growth is a phenomenon observed in containment vessels subjected to internal blast loading. The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage. The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using LS-DYNA. The development of bending modes and the interaction between the breathing mode and bending modes are observed. The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels. It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth. 相似文献
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陆轶之 《青海师范大学学报(哲学社会科学版)》2010,32(1):81-85
在全球化的背景下,美国对苏联进行战略遏制、经济封锁和贸易禁运,通过经济、贸易、金融和技术等手段对苏联经济进行战略挤压、围堵、控制、诱导等政策,加剧苏联经济困难并引发国内一系列问题,最终导致苏联解体,走向西方资本主义社会。 相似文献