金属嵌入对三角晶格耦合腔光波导群速度的影响

利用多重散射法和时域有限差分法理论,研究了二维三角晶格光子晶体耦合腔光波导的传输特性.理论模拟结果表明,在耦合腔光波导中嵌入半径很小的理想金属丝,能有效地减弱相邻点缺陷之间的耦合强度,实现了比真空中光速小三个数量级的群速度.     

A study of hadronic shower development in the ECAL of the alpha magnetic spectrometer Ⅱ

In this paper, we studied the development of hadronic shower in an electromagnetic calorimeter of Alpha Magnetic Spectrometer Ⅱ. Two parametrized empirical formulae were proposed to describe the hadronic shower shape in calorimeter. Using 100 GeV proton beam incident on the center of the ECAL, detailed plots of lateral and longitudinal hadronic shower behavior were given and we found the formulae can describe the development of the hadronic shower with the test beam data. The possible application of the parametrized formulae including e^±-π^± discrimination and tau jet reconstruction was discussed.     

非奇H-矩阵的新判定准则

正1引言非奇H-矩阵在数学、物理、控制论及经济学等许多领域有着重要的研究价值和实用价值.但判定一个矩阵是否为非奇H-矩阵却比较困难.近年来,国内外许多学者提出了一些实用的判定条件~([1-6]).本文根据α-对角占优矩阵与非奇H-矩阵的关系,给出了非     

Excel作图和二分法结合解超越方程的一种方法

利用Excel作图和二分法结合解超越方程,既能总体上把握解的概况,又能快速地得到各个解的高精度近似结果,是一种简单、实用的超越方程解法。     

黑体热辐射的光波长定义域研究

对黑体热辐射的光波长定义域进行了深入研究．结果表明,热辐射光波长定义域与温度和计算精度因子有关,温度越低,精度因子越大,长波长界越长;温度越高,精度因子越大,短波长界越短;由光波长定义域引起的热辐射功率计及误差与温度无关,且精度因子大于3时,该误差便小于万分之几．     

3,4,5-三甲氧基苯甲酸酯化壳聚糖的紫外吸收性能研究

将壳聚糖在甲磺酸中充分溶胀后,与3,4,5-三甲氧基苯甲酰氯反应,得到壳聚糖改性高分子紫外 线吸收剂。FTIR的表征表明:与壳聚糖相比,改性产物的红外谱图中1 720 cm-1处归属于C=O伸缩振动和 1 160 cm-1处归属于C-O-C对称伸缩振动的吸收峰显著增强,表明了酯化反应的发生。紫外光谱表明:产 物在220nm和274nm处具有较强的吸收峰。通过元素分析计算出不同投料比下所得改性产物的取代度,并 结合紫外光谱测试所得的数据,计算出了改性产物在273 nm处的摩尔消光系数e为8 205.9 L／(mol·cm)。     

ICP-MS测定纯铜中的铋、镍、铅和锌

ICP-MS测定纯铜中的铋、镍、铅和锌,简便、快速,其检出限为0.03—0.90μg/g之间,准确度及精密度均能满足分析要求。     

ICP-MS测定无公害环评总悬浮颗粒物中的铅

在仪器最佳条件下,样品经前处理后,采用ICP-MS和AAS2种方法测定无公害大气总悬浮颗粒物中铅及其化合物的含量,最终2种方法的测定结果一致,但ICP-MS线性范围宽、检出限低、精密度好。     

Measurement of avalanche size and position resolution of RPCs with different surface resistivities of the high voltage provider

The effects of surface resistivity of the high voltage provider on the space dispersion of the induced charge of a prototype Resistive Plate Chamber （RPC） have been studied experimentally and theoretically. The results of both experiment and theory agree and confirm that a two-Gaussian function can be used to fit the dispersion of the induced charge of the RPC. It is shown that the Gaussian function with the narrower width is mainly due to the expansion of the avalanche charge in the gas gap of the RPC, and the Gaussian function with the larger width is due to the charge dispersion when it passes through the resistive carbon film. This will be useful in the RPC design when one wants to make an RPC with high position resolution.     

High Characteristic Temperature 1.3μm InAs/GaAs Quantum-Dot Lasers Grown by Molecular Beam Epitaxy

We report the molecular beam epitaxy growth of 1.3 μm InAs/GaAs quantum-dot （QD） lasers with high characteristic temperature T0. The active region of the lasers consists of five-layer InAs QDs with p-type modulation doping. Devices with a stripe width of 4 μm and a cavity length of 1200 μm are fabricated and tested in the pulsed regime under different temperatures. It is found that T0 of the QD lasers is as high as 532 K in the temperature range from 10°C to 60°C. In addition, the aging test for the lasers under continuous wave operation at 100°C for 72 h shows almost no degradation, indicating the high crystal quality of the devices.