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61.
对由一类非线性抛物型变分不等方程所描述的无穷维动力系统,给出了存在全局吸引子及弱近似惯性流形的充分条件.  相似文献   
62.
L-Quebrachitol (1) isolated from the root of Elaeagnus formosana Nakai (Elaeagnaceae) has not been reported before for any species of the genus of Elaeasnus. Its structure was established from spectral data and was completely characterized by single-crystal X-ray analysis. L-Quebrachitol crystallizes in the monoclinic system, space group P21, with cell parameters are a = 6.702(4), b = 7.207(4), c = 8.758(5) Å, β = 90.24(5)° and Z = 2.  相似文献   
63.
环状连续强激光下光学薄膜的瞬温和热畸变   总被引:1,自引:0,他引:1       下载免费PDF全文
详细研究了非冷却光学薄膜元件在环形激光光束辐照下的瞬态温度分布和随后的热畸变,并且用泰曼干涉仪实际测量了连续波氧碘激光辐照各种非冷却光学元件的热畸变量并与理论计算相比较,分析结果表明理论和实验相一致。  相似文献   
64.
The noise characteristics of semiconductor laser amplifiers (SLAs) in the Ga1-xInxAs/GaInAsP/InP strained quantum well (QW) system are theoretically calculated and analyzed using density-matrix theory and taking into account the effects of band mixing on both the valence subbands and the transition dipole moments. The numerical results show that a reduced noise figure can be obtained in both tensile and compressively strained QW structures due to the increase in differential gain and the decrease in transparent carrier density. From a comparison among compressively strained (x=0.70), unstrained (x=0.53), and tensile strained (x=0.40) QW SLAs at a fixed carrier density and optical confinement factor, it is found that the noise figure of the tensile strained QW reaches its lowest value of 3.4 dB at average input optical power of -20 dB  相似文献   
65.
我们已通过实验证实,激光照射一侧合谷穴能够使正常人及癫痫病人的脑电产生即时影响。为了探讨远离大脑的合谷穴是如何影响脑电变化的,本文实验应用了体感诱发电位这一新兴的检查技术,以求在神经电生理方面进一步探讨激光针的作用机制。  相似文献   
66.
Polycrystalline Pb(Zr0.55Ti0.45)O3 thin film was deposited on Pt/Ti/SiO2/Si(1 0 0) by radio-frequency-magnetron sputtering method, and the writing of charge bits on the surface of PZT thin film was studied by Kelvin probe force microscopy. It is found that the surface potential of the negative charge bits are higher than those of the corresponding positive ones. When ferroelectric polarization switching occurs, the potential difference becomes even more remarkable. A qualitative model was proposed to explain the origin of the asymmetric charge writing. It is demonstrated that the internal field in the interface layer, which is near the ferroelectric/electrode interface in ferroelectric film, is likely to be the cause for the occurrence of this phenomenon.  相似文献   
67.
黄先开 《应用数学》1991,4(3):30-35
本文在跨共振点条件下证明n维Lienard型方程存在2π周期解.  相似文献   
68.
This paper reports that the growth of RuOx(110) thin layer growth on Ru(0001) has been investigated by means of scanning tunnelling microscope (STM). The STM images showed a domain structure with three rotational domains of RuOx(110) rotated by an angle of 120℃. The as-grown RuOx(110) thin layer is expanded from the bulk-truncated RuOx(110) due to the large mismatch between RuOx(110) and the Ru(0001) substrate. The results also indicate that growth of RuOx(110) thin layer on the Ru(0001) substrate by oxidation tends first to formation of the Ru-O (oxygen) chains in the [001] direction of RuOx(110).  相似文献   
69.
黄小青  文灏  王芙蓉 《通信技术》2002,19(12):70-72
描述了H.248协议的连接模型和消息结构,分析了H.248协议在UMTS核心网中的实现方案,并给出了一个应用实例,最后探讨了实现中可能面对的问题和解决方案。  相似文献   
70.
The In-Sn-Ni alloys of various compositions were prepared and annealed at 160°C and 240°C. No ternary compounds were found; however, most of the binary compounds had extensive ternary solubility. There was a continuous solid solution between the Ni3Sn phase and Ni3In phase. The Sn-In/Ni couples, made of Sn-In alloys with various compositions, were reacted at 160°C and 240°C and formed only one compound for all the Sn-In alloys/Ni couples reacted up to 8 h. At 240°C, Ni28In72 phase formed in the couples made with pure indium, In-10at.%Sn and In-11at.%Sn alloys, while Ni3Sn4 phase formed in the couples made of alloys with compositions varied from pure Sn to In-12at.%Sn. At 160°C, except in the In/Ni couple, Ni3Sn4 formed by interfacial reaction.  相似文献   
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