993 resultados para 154-928C
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<正>平晶型激光错位干涉仪(简称平晶干涉仪)的原理是:由激光器发出的激光经扩束平行光管后,变成一束截面积大、方向性良好的平面波,它通过被测系统后依次在一块平晶的前后表面反射,形成位置稍稍错开的两束光,其重迭部分出现干涉图案.它本质上是一种波前干涉仪.本文对平面波前检验及球面波前检验两种情况进行了理论分析,其主要结论最:对于理想平面波前及满足一定条件时的理想球面波前,其干涉图案是一组平行等间距直线条纹,而被测系统的非理想性则导致干涉条纹的弯曲.平面波前检验主要用于气、液体流场观测及透明固体介质的均匀性检验,文中给出了介质密度差与干涉图案形状的定量夫系.球面波前
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<正>由于非稳定腔具有大的可控模体积,采用共焦结构可以稳定输出平行光,准直后的光斑有最强的中心主瓣等优点,在大能量大菲涅耳数的激光器件中应用很广.但它的光学调准要求在10微弧度以上,因此,调准方法成为获得稳定运转的关键之一.本文介绍两种高精度调准方法.(1)微孔法:三个主要内容是微孔、叉丝和迭象.微孔在光学系统中可得到大的景深.通过微孔,人眼可看到叉丝的各次反射象迭合在一起,将它们按对接法对准可获得极高的调准精度.在正支非稳定腔结构的输出位置上设照明分划板.人眼通过微孔观察调准的各个阶段.最后使所有分划线的象重合在一起.
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通过模拟分析 ,对激光毛化 18 8不锈钢的疲劳寿命与毛化覆盖率的关系进行研究 ,预测结果与相关实验结果进行对比。结果显示 ,由于激光毛化处理的影响 ,18 8不锈钢的疲劳寿命得到改善 ,而且在毛化覆盖率为 2 0 %左右时 ,材料疲劳性能最好
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2006年12月1日是国际著名的力学家、应用数学家谈镐生院士诞辰九十周年纪念日.为纪念谈先生在力学学科的卓越贡献,缅怀他对推动我国力学基础研究和培养科技人才所作出的杰出贡献,中科院力学所于这天上午在所礼堂隆重举行“纪念谈镐生先生诞辰九十周年暨基础力学学术会议”.会前举行了《谈镐生先生文集》首发式,该文集由胡文瑞院士主持编辑,科学出版社出版,收录了谈镐生先生在流体力学、稀薄气体动力学和应用数学研究领域的论文和研究报告26篇,谈先生倡导和推行力学基础研究的有关文章和论述21篇,谈先生的学术活动和生活图片多幅,简介了谈先生生平.
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通过 3种密度硬质聚氨酯泡沫塑料的拉伸实验 ,研究了它们的应力 -应变特性及其应变率效应。同时 ,为确定泡沫塑料拉伸失效机理 ,对材料进行了扫描电镜下的细观拉伸实验 ,观察了试件表面胞体的变形与失效过程 ,再结合宏观拉伸试件断口的扫描电镜分析 ,进一步讨论了泡沫塑料在拉伸加载下的失效机理。基于泡沫塑料的拉伸应力 -应变曲线 ,用数值方法拟合了泡沫塑料的拉伸本构关系。
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1955年,钱学森冲破重重阻挠回到祖国,并与钱伟长等一道创建了中国科学院力学研究所。2005年12月6日,我所召开“庆祝中国科学院力学研究所建所50周年暨钱学森同国50周年大会”,中国科学院副院长曹健林、两弹一星功勋奖章获得者陈能宽院士、钱学森的学术秘书涂季同志、钱学森的儿子钱永刚、女儿钱永真、国防科工委、总装备部、中国工程物理研究院、中国海洋石油总公司、国家自然科学基金委、兄弟院所和高校的有关领导和专家学者以及力学所职工共计300余人出席了大会,路甬祥院长、白春礼常务副院长、原国务委员、中国科学院原党组书记张劲夫同志为力学所建所50年和钱老回国50年题词。
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“细观力学面临的新挑战国际会议”(“International Conference on New Challenges in Mesomechanis”)于2002年8月26~30日在丹麦奥尔堡(Aalborg)召开,由奥尔堡大学(Aalborg University)主办。与会人数约120人,分别来自丹麦、中国、希腊、俄国、德国、美国、英国、日本等20多个国家。会议上报告论文100余篇。我国有12人(包括大陆、香港、台湾)参加会议,在会上作了10个报告。
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[EN]A study was conducted on crossbred steers (n=275; 376±924 kg) to evaluate performance and carcass quality of cattle fed wheat or corn dried distillers’ grains with solubles (DDGS). The control ration contained 86.6% rolled barley grain, 5.7% supplement and 7.7% barley silage (DM basis). The four treatments included replacement of barley grain at 20 or 40% of the diet (DM basis) with wheat or corn DDGS. Steers were slaughtered at a common end weight of 645 kg with 100 steers randomly (n=20 per treatment) selected for determination of the retail yield of sub-primal boneless boxed beef (SPBBB). Data were analyzed as a completely randomized design using pen as the experimental unit. Feeding increasing levels of wheat DDGS led to a quadratic increase in dry matter intake (DMI) (P<0.01), whereas increasing levels of corn DDGS led to a quadratic decrease in DMI (P=0.01). Average daily gain was not influenced (P=0.13) by feeding wheat or corn DDGS, but cattle fed corn DDGS exhibited a quadratic increase (P=0.01) in gain:feed. As a result, a quadratic increase (P<0.01) in calculated NEg of the diet was observed as corn DDGS levels increased. A linear decrease (P=0.04) in days on feed (169, 166 and 154 d) was noted when increasing levels of wheat DDGS (0, 20 and 40%) were fed. Dressing percentage increased in a linear fashion with wheat DDGS (P<0.01) inclusion level and in a quadratic fashion (P=0.01) as corn DDGS inclusion level increased although other carcass traits were not affected (P=0.10) by treatment. The results indicate that replacement of barley grain with corn or wheat DDGS up to 40% of the diet (DM) can lead to superior performance (improved gain:feed or reduced days on feed, respectively) with no detrimental effect on quality grade or carcass SPBBB yield.
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Ejemplar dedicado a: Beñat Oihartzabali gorazarre - Festchrift for Bernard Oyharçabal/ Ricardo Etxepare, Ricardo Gómez, Joseba Andoni Lakarra ( eds.)
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Lei nº 12.663, de 5 de junho de 2012, que dispõe sobre as medidas relativas à Copa das Confederações Fifa 2013, à Copa do Mundo Fifa 2014 e à Jornada Mundial da Juventude 2013, que serão realizadas no Brasil; altera as Leis nos 6.815, de 19 de agosto de 1980, e nos 10.671, de 15 de maio de 2003; e estabelece concessão de prêmio e de auxílio especial mensal aos jogadores das seleções campeãs do mundo em 1958, 1962 e 1970
Effects of shear on eggs and larvae of striped bass, morone saxatilis, and white perch, M. americana
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Shear stress, generated by water movement, can kill fish eggs and larvae by causing rotation or deformation. Through the use of an experimental apparatus, a series of shear (as dynes/cm2)-mortality equations for fixed time exposures were generated for striped bass and white perch eggs and larvae. Exposure of striped bass eggs to a shear level of 350 dynes/cm2 kills 36% of the eggs in 1 min; 69% in 2 min, and 88% in 4 min; exposure of larvae to 350 dynes/cm2 kills 9.3% in 1 min, 30.0% in 2 min, and 68.1% in 4 min. A shear level of 350 dynes/cm2 kills 38% of the white perch eggs in 1 min, 41% in 2 min, 89% in 5 min, 96% in 10 min, and 98% in 20 min. A shear level of 350 dynes/cm2 applied to white perch larvae destroys 38% of the larvae in 1 min, 52% in 2 min, and 75% in 4 min. Results are experimentally used in conjunction with the determination of shear levels in the Chesapeake and Delaware Canal and ship movement for the estimation of fish egg and larval mortalities in the field.
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Parte 1 - Decisões
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Parte 1 - Leis.