Ga1-xInxAs/InAsyP1-y/InP异质结的MOCVD生长及表征

Ga1-xInxAs(x>0.53)材料是未来长距离低损耗光纤通信的理想光源材料和探测器材料之一.我们采用水平常压MOCVD系统,在InP衬底上成功地生长了Ga1-xInxAs(x>0.53)/InAsyP1-y/Inp异质结材料.其中InAs1-yPy为组份阶梯变化的多层结构.由样品的(400)面X光衍射结果测定了各层组份.由二次离子质谱(SIMS)得到了样品剖面组份变化结果,证明InAs1-yPy层组份为阶梯状变化的.通过对光致发光结果和X光衍射结果比较,可以看到,InAsyP1-y层通过位错和弹性畸变二种方式来释放或积累Ga1-xInxAs与InP间的失配应力,从而减少了Ga1-xInxAs中的失配位错.有效地改善了Ga1-xInxAs的质量.已获得了x高达0.94表面光亮的Ga1-xInxAs/InAs1-yPy/InP异质结材料.     

核磁共振弛豫速率方法测定模拟正铁色素的结构

在生命体系内正铁色素具有摄铁和输铁的功能,人工合成的模拟化合物具备了正铁色素的主要功能基团和相近的性质.本工作利用铁(Ⅲ)离子的顺磁性质,测定不同铁(Ⅲ)离子浓度下模拟正铁色素的诱导弛豫时间,根据简化了的Solomon—B1oemoergen公式,计算出铁(Ⅲ)离子到所有被测质子(即氢原子)的相对距离,比较清楚地得到模拟正铁色素在溶液中的构象。     

单扫描示波极谱测定痕量银

本文首次提出了运用单扫描极谱直接测定银的方法。在含N-烯丙基-N′-对苯磺酸钠硫脲及四乙烯五胺的硼砂缓冲液中,银离子在-0.66V(相对饱和甘汞电极)有一灵敏还原波。运用经典极谱或单扫描极谱,此波均可用于微量银的定量测定。“银波”的单扫描示波极谱波可在5×10~(-7)～3×10~(-5)mol/L范围内检测银。方法已用于废定影液中银含量的分析,结果满意。     

横向位移双曝光散斑图维纳谱的信息分布

讨论了横向位移双曝光散斑图维纳谱的信息分布，并由此导出杨氏纹图的一般表达式。讨论了条纹可见度与应变，面内转动，照明光束直径与条纹图图空间坐标的关系，指出了在条纹可见度影响下最大可见条纹数目。还讨论了散斑衬比与衍射晕的关系。     

热辐射驱动烧蚀平面金靶的数值定标定律

利用一维辐射流体力学编码数值研究了辐射烧蚀波在平面金靶中的传播情况,并在常温边界条件下得到了辐射流、烧蚀压、质量烧蚀率和特征等离子体密度的定标定律。     

PARAMETER ESTIMATION OF SPATIAL AR MODEL

Consider a stable AR model of two parameter spatial series {X_t, t∈N~2}, i. e. {X_(t)t∈N~2} is homogeneous and satisfies the following difference equationX_t-sum from n=s∈相似文献   

Research on Hawking Radiation as Tunneling from Schwarzshild-anti-de Sitter Black Hole

After taking into account energy conservation and the particle’s self-gravitation interaction, Hawking radiation of the massive particle as tunneling from Schwarzshild-anti-de Sitter black hole is studied by using Parikh-Wilczek’s semi-classical quantum tunneling approach. Meanwhile, Hawking radiation as tunneling from the black hole is reexamined by developing Angheben–Nadalini–Vanzo–Zerbini (ANVZ) covariant method to cover energy conservation and the particle’s self-gravitation interaction. Both the results perfectly generalize those obtained by Parikh and Wilczek, and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy, and the factual emission spectrum is not exactly thermal, but satisfies the underlying unitary theory. PACS: 04.70-s, 9760. Lf.     

Propagation of thickness-twist waves in a multi-sectioned piezoelectric plate of 6 mm crystals

We study thickness-twist vibrations and waves in an unbounded, multi-sectioned piezoelectric plate of crystals with 6 mm symmetry or polarized ceramics. An exact solution from the three-dimensional equations of piezoelectricity is obtained. Basic vibration and wave propagation characteristics are calculated based on the solution. The results are useful in the understanding and design of plate resonators, filters and acoustic wave sensors of ZnO, AlN and polarized ceramics.     

In situ observation of NaBi(WO4)2 dendrite growth and the study on microstructure of solidification

The dendrite growth process of transparent NaBi(WO₄)₂ with small prandtl and high melting point was studied by using the in-situ observation system. According to the dynamic images and detailed information, there are two kinds of restriction effect on the dendrite growth, the competition between arms and branches and the convection in the melt. The dendrite growth rate was time dependent, and the rate of arm growth reached the maximum 5.8 mm/s in the diffusive-advective region and rapidly decreased in the diffusive-convective region. The growth rate of branch had the same change trends as the arm’s. Based on the EPMA-EDS data of solidification structure of quenched NaBi(WO₄)₂ melt, it was found that there were component differences from stoichiometric concentration in the melt near the interface during the growth process. Supported by the National Natural Science Foundation of China (Grant No. 50331040) and the Innovation Funds from Shanghai Institute of Ceramics, Chinese Academy of Sciences (Grant No. SCX0623)     

Explicit bounds on some new nonlinear integral inequalities with delay

The purpose of the present note is to establish some new delay integral inequalities, which provide explicit bounds on unknown functions and generalize some results of Li et al. [Some new delay integral inequalities and their applications, J. Comput. Appl. Math. 180 (2005) 191–200]. The inequalities given here can be used to investigate the qualitative properties of certain delay differential equations and delay integral equations.