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991.
为进一步提高Y2O2S∶Eu3+的发光性能,采用改善主要原材料Y2O3结晶性的方法,使Y2O2S∶Eu3+红色荧光粉在20 kV和25 kV下发光强度分别增强5%和10%,且不影响色度、粒度、粉体分散性等主要考核指标。提高了粉体的耐电压特性(发射强度与激发电压间的关系特性)。讨论和分析了发射强度增强、电压特性改善的原因:主要原材料Y2O3的结晶性的改善,使得合成的Y2O2S∶Eu3+具有更好的晶体质量,Eu3+离子晶场环境得到进一步改善,从而减弱了无辐射过程及因晶格畸变所造成的能量损失,发光效率得到增强,电压特性得到改善。实验表明,获取高质量多晶Y2O3的最佳分解温度为1400℃左右。 相似文献
992.
Minoru Hirano 《Journal of voice》1988,2(4):291-300
Behavior of the cricothyroid, lateral cricoarytenoid, vocalis, and interarytenoid muscles of William D. Vennard was electromyographically investigated. This article demonstrates electromyographic recordings that have not been published. Data presentation and discussion are focused on vocal registers, some phrases for voice training and warm-up, vowels, phonation modes, fundamental frequency control, the interarytenoid muscle, and some nonsinging behaviors 相似文献
993.
Using various formulae describing the field near the caustic, the amplitude distribution along the direction perpendicular to the smooth branch of the caustic of A2 type was calculated and then compared with the results of numerical calculations based on the Kirchhoff integral. 相似文献
994.
N. G. Semaltianos A. De Rossi B. Vinter V. Berger M. Calligaro V. Ortiz 《Optics & Laser Technology》2004,36(8):669-676
AlGaAs-based quantum well laser structures with third-order waveguide mode emission at 775 nm are a promising route toward compact twin-photon sources at 1.55 μm based on the principle of modal phase matching between the pumping frequency and fundamental modes at half frequency in III–V semiconductor waveguides. Following the demonstration and characterization of an optically pumped third-order mode semiconductor laser, in this paper we present data of the corresponding structure under conditions of electrical pumping. By pumping electrically and optically the same sample made for current injection, identical transverse far-field angular laser mode profiles are measured and with very low parasitic losses. Although they do not follow the third-order mode emission pattern as it is expected, however this means that the different way of pumping, that of the electrical one as compared to optical pumping is not responsible for the absence of third-order mode emission. Furthermore, since the undoped optically pumped laser sample correctly emits on the third-order mode, it is concluded that the cladding layers of the structure still need to be optimized in doping and thickness, in order to reduce the internal losses for the third-order mode. 相似文献
995.
Theoretical expressions for the overall values of three Booth type R-indices based on intensity variables are derived. The
results are applicable to crystals of any space group containing any number and type of atoms at general positions in the
asymmetric unit. The theoretical results were tested in the case of models of a few crystal structures. 相似文献
996.
超短超强激光和稠密等离子体相互作用的数值研究 总被引:1,自引:0,他引:1
应用一维粒子模拟方法数值研究了超短超中激光和稠密等离子体的相互作用,结果表明,在等离子体中的激发起无规则的电场波动,同时在等离子体中产生温度很高的电子。 相似文献
997.
Zhao Xia Ouyang Zisheng 《高校应用数学学报(英文版)》2005,20(3):289-296
In this article, the risk process perturbed by diffusion under interest force is considered, the continuity and twice continuous differentiability for Фδ(u,w) are discussed,the Feller expression and the integro-differential equation satisfied by Фδ (u ,w) are derived. Finally, the decomposition of Фδ(u,w) is discussed, and some properties of each decomposed part of Фδ(u,w) are obtained. The results can be reduced to some ones in Gerber and Landry's,Tsai and Willmot's, and Wang's works by letting parameter δ and (or) a be zero. 相似文献
998.
The model of structural interfaces developed in Part I of this paper allows us to analytically attack and solve different problems of stress concentration and composites. In particular, (i) new formulae are given for effective properties of composite materials containing dilute suspensions of (randomly oriented) reinforced elliptical voids or inclusions; (ii) a new definition is proposed for inclusion neutrality (to account for the fact that the matrix is always ‘overstressed’, and thus non-neutral in a classical sense, at the contacts with the interfacial structure), which is shown to provide interesting stress optimality conditions. More generally, it is shown that the incorporation of an interfacial structure at the contact between two elastic solids exhibits properties that cannot be obtained using the more conventional approach of the zero-thickness, linear interface. For instance: contrary to the zero-thickness interface, both bulk and shear effective moduli can be optimized for a structural interface; effective properties higher that those possible with a perfect interface can be attained with a structural interface; and neutrality holds with a structural interface for a substantially broader range of parameters than for a zero-thickness interface. 相似文献
999.
常宏宇 《数学的实践与认识》2007,37(13):52-56
介绍了典型电磁现象的可视化实现过程.用计算机模拟计算出典型电磁现象在空间的分布情况,因此我们可以用图形方式来观察典型电磁现象.同时给出了几个具体实例. 相似文献
1000.