23 resultados para 624.012.45

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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材料的疲劳过程是能量耗散的过程,在宏观上表现为热耗散,能量理论是研究材料疲劳行为微观机理和宏观现象的桥梁。文中利用红外热像仪对具有颈缩部分的45号钢试件疲劳过程中的温度变化进行了研究,探讨了影响温度变化的机制,并介绍了快速确定45号钢疲劳极限的方法。实验结果表明,该方法所测得的疲劳极限合理,且该方法具有非接触、便捷、低成本等优点。

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采用激光离散预处理钢基体再电镀铬层技术得到了一种新型复合结构,研究了这种新型复合结构在拉伸载荷作用下的开裂行为特征,并与无激光处理钢基体的试样在同样试验条件下的开裂特征进行了对比分析。结果表明:有激光离散预处理钢基体试样的承载能力要高于无激光预处理钢基体试样的承载能力,且有激光处理的试样开裂区域在两个激光带之间(无激光处理区),主裂纹呈现明显的周期性特征。本研究结果可归结为激光预处理钢基体不仅改善了基体表层的应力状态和力学性能,而且还改善了后续铬镀层的力学性能。

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提出了一种精确测量1/4波片相位延迟量的新方法。测量光路由激光器、起偏器、被测1/4波片、光弹调制器、检偏器和光电探测器构成。起偏器和检偏器的透光轴相互垂直。被测1/4波片的快轴与光弹调制器的振动轴平行,且与起偏器和检偏器的透光轴分别成±45°夹角。准直激光束依次经过起偏器、被测1/4波片、光弹调制器和检偏器的探测光强由光电探测器接收。利用探测信号的直流分量与二次谐波分量精确计算出被测1/4波片的相位延迟量。实验验证了这种测量方法的有效性,改变初始光强过程中相位延迟量测量结果的复现性为0.012°,检偏器

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提出了一种基于基频分量消光的波片快轴标定方法,并利用琼斯矩阵对其标定原理进行了分析。激光器、起偏器、相位调制器、待标定1/4波片、检偏器和光电探测器构成标定光路,起偏器、检偏器的透光轴与相位调制器的振动轴分别成+45°和0°夹角。准直激光束依次经过起偏器、相位调制器、待标定1/4波片和检偏器,由光电探测器接收。理论分析表明该标定方法标定精度主要取决于检偏器的定位误差。实验验证了该标定方法的有效性,1/4波片快轴标定结果的最大偏差为0.043°,标准差为0.012°,标定精度为0.05°。

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Immersion lithography has been considered as the mainstream technology to extend the feasibility of optical lithography to further technology nodes. Using proper polarized illumination in an immersion lithographic tool is a powerful means to enhance the image quality and process capability for high numerical aperture (NA) imaging. In this paper, the impact of polarized illumination on high NA imaging in ArF immersion lithography for 45 nm dense lines and semi-dense lines is studied by PROLITH simulation. The normalized image log slope (NILS) and exposure defocus (ED) window are simulated under various polarized illumination modes, and the impact of polarized illumination on image quality and process latitude is analyzed. (C) 2007 Elsevier GmbH. All rights reserved.

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A method for the control of polarization for a broadband dichroic filter was reported and some design examples were elaborated. This method could be applied over a wide range of wavelengths and a wide range of polarizations in the transmission region. A nonpolaiizing broadband dichroic filter and a broadband dichroic filter with certain polarization were designed and fabricated by electron beam evaporation with ion beam assisted deposition. The experimental spectral performances showed good agreement with their theoretical curves. In addition, the application of the method was discussed. (c) 2007 Optical Society of America

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试验测定了氯化铵对草鱼的急性和亚急性毒性。急性试验采用26,47,60和125日龄的草鱼,亚急性试验用60日龄草鱼种,经0.970,0.455,0.099,0.054和0.012(对照)毫克NH_3/升(未离解氨,un-ionized ammonia)暴露45天。26,47,125日龄草鱼的96小时LC_(50)(半数致死浓度)分别是0.570,1.609和1.683毫克NH_3/升,而47,60,125日龄的48小时LC_(50)则分别为1.727,2.050和2.141毫克NH_3/升。急性毒性试验结

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Optimized AlGaN/AlN/GaN high electron mobility transistor (HEMT) with high mobility GaN channel layer structures were grown on 2-in. diameter semi-insulating 6H-SiC substrates by MOCVD. The 2-in. diameter GaN HEMT wafer exhibited a low average sheet resistance of 261.9 Omega/square, with the resistance un-uniformity as low as 2.23%. Atomic force microscopy measurements revealed a smooth AlGaN surface whose root-mean-square roughness is 0.281 nm for a scan area of 5 x 5 mu m. For the single-cell HEMTs device of 2.5-mm gate width fabricated using the materials, a maximum drain current density of 1.31 A/mm, an extrinsic transconductance of 450 mS/mm, a current gain cutoff frequency of 24 GHz and a maximum frequency of oscillation 54 GHz were achieved. The four-cell internally-matched GaN HEMTs device with 10-mm total gate width demonstrated a very high output power of 45.2 W at 8 GHz under the condition of continuous-wave (CW), with a power added efficiency of 32.0% and power gain of 6.2 dB. To our best knowledge, the achieved output power of internally-matched devices are the state-of-the-art result ever reported for X-band GaN-based HEMTs. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.

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讨论了一种类似蜂窝或V型膜的玻璃盖板与45°膜复合结构(简称45°膜结构)的光热性能。其透过率比蜂窝结构高,隔热性能与蜂窝结构和V型膜结构相当,在低纬地区应用效果甚好。

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在黑白仰鼻猴(Rhinopithecus bieti)分布区北端的南仁(99o04’E, 28o34’N), 野外工作分别于2001年4月10日 - 6月30 日(代表冬末和春季),9月14日 - 12月20日(夏秋季)进行。我们分别用粪便取样法、录像带记录和直接观察法收集了猴群生境的垂直利用、过夜处选择和社会组织数据。此外,我们于1998年8月20日到12月31日在中科院昆明动物研究所老所利用全发生取样法(All-Occurence sampling)收集了一个单雄多雌单元(One-male, multi-female unit: OMU)的性行为数据。另外,我们利用昆明动物所1994 - 2003年和昆明动物园1991 - 2003年笼养黑白仰鼻猴群的出生记录来说明出生季节和出生间隔。 黑白仰鼻猴群全年在3500 - 4300 m的林带上活动,集中利用的海拔带为3900 - 4200 m,这可能与猴群的主食(松萝)主要分布于高海拔有关。冬季, 山沟中的粪便密度高于山脊,这可能是猴群在沟中过夜的缘故。猴群喜欢在树高(27.5 ± 3.2 m)较高、胸径(57.9 ± 16.9 cm)和树冠(6.3 ± 1.4 m)大的针叶树(云冷杉)上过夜。猴群冬季喜欢在阳坡中部的针叶树上过夜,这样既安全又可以接受适量的阳光照射。这是猴群在选择最安全和最暖和过夜处的一种折衷策略。 1994年猴群OMUs大小为7.8 ± 1.7(n = 17),成年性比(M/F)是1.0: 3.8。2001年OMUs大小为10.1 ± 3.7 (n = 15),成年性比是1.0: 4.9。1994-2001年,OMUs中每个成年雌性每年的平均增长率是0.04。这种OMU-band两层社会组织与Kirkpatrick(1996)的报道一致。 雌性以匍匐地面或栖木上,同时面部和视线左右摆动,或者坐着上下移动头部的动作邀配;雄性则以伴有特别的叫声、露齿动颌表情邀配。在有射精记录的观察日中,平均每5.2次爬跨有1次射精,而单次爬跨就射精的仅占4.4%。雌性邀配了18次射精爬跨的大多数(72%),但163次非射精爬跨中她们邀配的仅为45%。雄性在射精交配中叫声多于非射精交配。该种交配模式与其它疣猴亚科动物相似,而性内交配竞争可能与这种模式的进化有关。 笼养黑白仰鼻猴群的出生日期为12 - 6月份,出生高峰期为3 - 5月份。猴群的平均出生日期为4月18日(标准差为43天),中位出生日期为4月10日。猴群的出生间隔平均为624 ± 150天(n = 15,范围:332 - 787天)。幼猴可活到1岁后的出生间隔(706 ± 71, n = 12, 498 - 787天)显著长于1岁内死亡或流产后的出生间隔(428 ± 87, n = 5, 332 - 568天)。婴猴性比(M/F)显著偏离1: 1。

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测量了自组织多层In_(0.55)Al_(0.45)As/Al_(0.5)Ga_(0.5)As量子点的变温光致发光谱,同时观察到来自浸润层和量子点的发光,首次直接观察了浸润层和量子点之间的载流子热转移。分析发光强度随温度的变化发现浸润发光的热淬灭包括两个过程

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在15K测量了不同尺寸分布的In_(0.55)Al_(0.45)As/Al_(0.5)Ga_(0.5)As量子点的静压我致发光,静压范围为0--1.3GPa。常压下观察到三个发光峰,分别来源于不同尺寸的量子点(横向直径分别为26、52和62nm)的发光。它产的压力系数分别为82、94和98meV/GPa,都小于In_(0.55)Al_(0.45)As体材料带边的压力系数,特别是尺寸为26nm的小量子点比In_(0.55)Al_(0.45)As体材料带边小17%,并且压力系数随量子点尺寸的变小而减小。理论计算表明有效质量的增在和Γ-X混合是量子点压力系数变小的主要原因,并得到横向直径为26和52nm的小量子点的Γ-X混合势为15和10meV。根据实验还确定In_(0.55)Al_(0.45)As/Al_(0.5)Ga_(0.5)As量子点系统X能带具有Ⅱ类结构,并且估算出价带不连续量为0.15±0.02。