58 resultados para Malón de Chaide, 1530-1589.

em Chinese Academy of Sciences Institutional Repositories Grid Portal


Relevância:

10.00% 10.00%

Publicador:

Resumo:

针对广泛应用于超燃冲压发动机的吸热碳氢燃料,简要介绍了用于模拟燃料热物理特性的替代燃料方法和广义对应状态法则.以大庆RP-3航空煤油为例,选择了一个由49%(摩尔比)正十烷,44%1,3,5-三甲基环己烷以及7%正丙基苯组成的替代煤油用来模拟RP-3航空煤油进行热物理特性研究,并采用广义对应状态法则对替代煤油热力学和输运特性进行了数值研究.在此基础上,提出了预测超临界态流体通过音速喷管流量的新方法并得到了实验验证.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

在单脉冲激波管上,研究了1,2-二氯乙烷的热裂解.实验的激波条件为:温度区间1020 K<T<1190 K, 压力: P=0.12 MPa,实验时间τ=0.5 ms;实验气体为1,2-二氯乙烷稀释于Ar气中(3.95 mmol/L).以4-甲基-1-环己烯作为对比速率法实验的内标物,用4-甲基-1-环己烯开环反应的速率常数k=1015.3exp(-33400/T) s-1,以及从其产物的浓度推定出实验温度.经激波加热后的实验气体的终产物用气相色谱分析出主要成分为C2H3Cl,指示出主要反应通道为β消去反应.如把所有产物C2H3Cl都归于β消去反应,则可推定出表观之反应速率常数k1a=5.0×1013exp(-30000/T) s-1.对于由C-Cl键断键反应引发的链反应的可能影响做了分析研究.用了一种简便分析可推知在实验的温度范围内的低端(1020 K)链反应的影响可以忽略,而在其高端(1190 K)链反应将给出10%的终产物C2H3Cl的附加浓度,获得真实的β消去反应速率常数则必须把这部分予以扣除.经过这样的校正之后,最后得到CH2ClCH2Clβ消去反应速率常数为k1c=2.3×1013exp(-29200/T) s-1.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

研究了超短脉冲激光照射下LiF晶体的破坏机理及其超快动力学过程,利用扫描电镜和原子力显微镜等测试手段,观测了飞秒激光照射下LiF晶体的烧蚀形貌。利用烧蚀面积与激光脉冲能量的对数关系确定了LiF晶体的破坏阈值,并利用非线性玻璃棒展宽脉宽,得到了800nm激光作用下LiF破坏阈值对激光脉宽(50~1000fs)的依赖关系;利用抽运一探针超快探测平台,探测了LiF烧蚀过程中反射率的变化。采用雪崩击穿模型,并根据晶体材料反射率与材料的介电常量的依赖关系,通过数值计算,模拟了材料烧蚀阈值与脉宽的依赖关系及材料激发过

Relevância:

10.00% 10.00%

Publicador:

Resumo:

通过在线形谐振腔中引入一段缠绕在压电陶瓷上的单模光纤作为正弦相位调制器,使得激射波长的损耗不固定,抑制由于掺铒光纤的均匀展宽效应引起的模式竞争,从而避免了在室温下不稳定的单波长激射,实现了多波长掺铒光纤激光器的稳定输出。为了获得平坦的多波长输出,在谐振腔里使用了一个损耗峰位于1530nm处的长周期光纤光栅,以获得较为平坦的增益谱。通过两个3dB耦合器制成的反射型梳状滤波器的滤波作用,实验中观察到稳定的多波长激射,相邻波长间隔约为0.45nm。中心9个波长的输出功率平坦度为10dB,边模抑制比大于25dB。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Mn:YAP晶体是近年来发现的一种新型光折变晶体,在三维全息存储方向有广阔的应用前景。总结了Mn:YAP的晶体结构、光谱特征及其光折变模型,分析了它的优点和不足,并对其研究方向提出了设想。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

在ffner展宽器的设计研究中,对曲面镜曲率半径的误差研究非常重要,它直接影响输出脉冲的质量。因此有必要分析ffner展宽器中曲面镜曲率半径的误差对输出脉冲对比度的影响。参考ffner展宽器的光线追迹模型,建立了ffner展宽器中曲面镜曲率半径存在误差时的光线追迹模型;根据建立的模型,详细分析了曲面镜曲率半径的误差对输出脉冲质量的影响;发现在目前曲面镜曲率半径的加工误差在0.2%~0.5%的情况下,完全可以满足神光II拍瓦激光装置中对展宽器的要求;同时发现如果曲面镜曲率半径存在误差时,应该尽量使两曲面镜之间的距离保持为凹面反射镜曲率半径的一半,而不是使两曲面镜保持同心。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

1999年,Cao等用皮秒级激光脉冲抽运ZnO颗粒(直径约为100nm)制成的粉末薄层,观察到了谱线宽度非常窄的激光辐射。本文初步研究了在纳秒级(脉宽8ns,频率30Hz)Nd:YAG脉冲激光器的抽运下,纳米ZnO粉末的发散光。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

For the Er3+/Yb3+ codoped fluorophosphate glasses, Judd-Ofelt theory is used to analyse the influence of YbF3 as not a sensitizer but an average component on the spectroscopic properties around 1530 nm emission. The double roles of Yb3+, as a sensitizer and as an average component, are discussed. It is found that Yb3+ as an average component contributes to the increase of fluorescence lifetime, and Yb3+ as a sensitizer has the best sensitization when its concentration is 2.4 mol%.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Er3+/Yb3+ cocloped fluorophosphate glasses were prepared and their thermal stabilities, Raman spectra, absorption spectra, and fluorescence spectra were measured. It is found that proper content of NaF or PbF2 is helpful for the increase of stability against crystallization. The variation of AI(PO3)3 or NaF content in the composition affects not the maximum phonon energy but the phonon density. The introduction of PbF2 decreases the phonon energy slightly. Intense green and red upconversion luminescence was observed for the fluorophosphate glass with low phosphate content. A glass matrix for upconversion luminescence requiring neither expensive raw material nor special atmospheric conditioned preparation is provided. Infrared luminescence around 1530 nm was researched. Fluorophosphate glasses with bandwidth properties and stimulated-emission cross sections better than tellurite, germanate and silicate glasses are obtained. Through the introduction of NaF, the bandwidth properties are decreased. Through the introduction of PbF2 the gain properties are increased. On the whole, it is difficult to obtain a material with the best gain properties and bandwidth properties simultaneously. There should be a compromise between them according to the demand. (C) 2006 Elsevier B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Broadband and upconversion properties were studied in Er3+/Yb3+ co-doped fluorophosphate glasses. Large Omega(6) and S-ed/(S-ed + S-md) values and the flat gain profile over 1530-1585 nm indicate the good broadband properties of the glass system. And a premise of using Omega(6) as a parameter to estimate the broadband properties of the glasses is proposed for the first time to our knowledge. Results showed that fluorescence intensity, upconversion luminescence intensity, the intensity ratio of red/green light (656 nm/545 nm) are closely related to the Yb3+:Er3+ ratio and Er3+ concentration, and the corresponding calculated lifetime of F-4(9/2) and S-4(3/2) states for red and green upconversion samples proves this conclusion. The upconversion mechanism is also discussed. (c) 2005 Elsevier Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Considering the interface absorption in optical coatings, we propose a model to simulate interface absorption. Calculations are made and the temperature field of several kinds of thin film multilayers, including those of partial reflectivity, high-reflectivity, and antireflectivity coatings are analyzed. The interface absorption is found to greatly influence the temperature distribution within multilayer coatings and to weaken the laser damage resistance of the samples. The real-time results of the photothermal deflection technique for laser induced damage to samples supports the model. (C) 1997 Society of Photo-Optical Instrumentation Engineers.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本文利用电子显微镜和光学显微镜研究了国产的蒿属花粉代表种和常见种共66种4变种,根据花粉外壁纹饰可将其分为六大类型:1、具刺状突起,排列不密集,刺间具颗粒状纹饰(类型—I)。2、刺状突起较类型—I稍为密集,没有或有少许颗粒状纹饰(类型—II)。3、具刺状突起,排列不密集,但刺间无颗粒状纹饰,较粗糙(类型—III)。4、刺状突起较类型—I稍为密集,刺间具发育的小芽胞状或颗粒状纹饰,小芽孢状突起顶部有的还可见有一小穿孔存在(类型-IV)。5、具微刺状突起,排列极稀,刺间较为平滑(类型—V)。6、刺状突起有大小之分,大刺较尖,还有颗粒状纹饰(类型—VI)。其中类型—I占绝对优势,其次为类型—II,类型—V和类型VI为较特殊的类型。 本文还对蒿属邻近属(即蒿自然群中的其它属)各属代表种花粉作了详细的研究,并和蒿属花粉作了比较。结果表明:按外壁纹饰可将蒿自然群分为两大类型:1、具明显的刺状纹饰。其中包括:亚菊属、女蒿属、百花蒿属。2、具退化状小刺。其中包括:蒿属、茶蒿属、线叶菊属、画笔菊属、喀什菊属、栉叶蒿属、绢蒿属。经研究我们认为在花粉形态上蒿自然群是一相互关联的有机整体,并从花粉形态的角度出发,文中讨论了紊蒿属和百花蒿属的分属问题,作者认为它们独立成两个单种属的意见较为妥当。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本试验采用水平式淀粉凝胶电泳法,对版纳斗鸡、武定鸡的60个样本,32个遗传位点的血液蛋白多态性进行了检测。这两个品种只在ES-1、AKp-1、AKp-2、LAP四个座位显示多态。其余25个位点均为单态,尚有CP、XDH和IDH三个座位染色后未出现谱带。试验结果表明:两鸡种之间虽呈现一定的遗传差异,但平均基因杂合度较小(0.0607;0.0648),两者间遗传距离较近(0.0778)。