布尔“复合函数”的Walsh循环谱和自相关函数

本文利用布尔随机变量联合分布的分解式给出了布尔“复合函数”和某布尔函数符合率的分解算式,由此求得了布尔“复合函数”的 Walsh循环谱和自相关函数的计算公式,公式清楚地表明了“复合”所得布尔函数的 Walsh循环谱与起“复合”作用的函数和被“复合”的各函数所有线性组合的 Walsh循环谱之间的关系、“复合”所得布尔函数的自相关函数与起“复合”作用的函数谱和被“复合”的各函数的谱及相关函数之间的关系,这两个公式在布尔函数的密码学性质研究中会有广泛的应用.     

玻璃中CdSeS纳米晶体的室温光致发光谱

对掺有过饱和的镉、硒和少量硫的玻璃在500～800℃分别退火4h,生长了不同尺寸的CdSe_1-xS_x纳米晶体。测量了纳米晶体的室温吸收光谱和光致发光(PL)光谱,550℃生长的样品在300～800nm的范围没有观察到吸收和发光峰,表明温度低于550℃玻璃中不能形成纳米晶体。生长温度在600～650℃,纳米晶体的PL光谱主要为两个宽的发光带,即带边激子发光带和通过表面态复合的发光带。随着生长温度的升高,带边复合发光的蓝移减小,通过表面态的发光逐渐消失,并出现了叠加于宽发光带上的一系列明显的弱发射峰。不同温度生长的样品中,叠加峰的能量相同。同一样品中叠加峰的能量不随激发光波长的变化而变化。     

测定汞原子塞曼谱线相对强度

在原塞曼效应实验基础上，测定了塞曼分裂各谱线的相对强度，以作为原实验的补充．     

不锈钢丝网上薄膜TiO2光催化剂的Raman光谱研究

用Raman光谱方法来研究用Sol Gel法负载于金属丝网的薄膜TiO2 光催化剂的物相结构、厚度以及粒径大小。研究结果显示 ,薄膜达到一定厚度能够阻止基底Fe元素向薄膜表层的扩散 ;在 4 0 0℃下灼烧制得的薄膜TiO2 光催化剂具有锐钛矿晶型 ,而高于 4 0 0℃时 ,将出现金红石相TiO2 ;锐钛矿晶型TiO2 的Raman特征峰产生偏移 ,表明薄膜粒径的变化 ,通过计算表明 ,薄膜TiO2 的粒径为 10nm左右 ,TEM的分析结果也与之一致。     

Eigenvalues of the antiplane-shear crack problem for a power-law material

This paper discusses the problem of finding the eigenvalue spectrum in determining the stress and strain fields at the tip of an antiplane-shear crack in a power-law material. It is shown that the perturbation method provides an analytical dependence of the eigenvalue on the material nonlinearity parameter and the eigenvalue of the linear problem. Thus, it is possible to find the entire spectrum of eigenvalues and not only the eigenvalue of the Hutchinson-Rice-Rosengren problem. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 1, pp. 173–180, January–February, 2008.     

The supersymmetric WKB approximation of ring-shaped oscillator potential in r and θ dimensions with spherical polar coordinates

According to calculation of the energy spectrum of ring-shape oscillator potential by using the supersymmetric WKB approximation, it is shown that the energy spectrum of some noncentral separable potentials can be exactly obtained in r and θ dimensions by above method.     

锥形光纤的偏振特性

随着光通信技术的不断发展，光纤的应用越来越广泛，而锥形光纤以其独特的传光方式越来越多地应用于光纤连接、成像及测量等领域。实验测定了不同锥角和不同长度锥形光纤的偏振特性。理论上，根据麦克斯韦方程组以及边界条件给出了光在理想光纤中的场分布，阐明了实际光纤中光的传输特性。论证了锥形光纤长度与其偏振特性的关系，进而利用几何光学方法对锥形光纤锥角与其偏振特性的关系作了定性说明。并用具体数据进行了定量计算，得出偏振光经锥形光纤传输或耦合后再传输到其终端所得到均是椭圆偏振光的结论。     

Particle Size Analysis by Transmission Fluctuation Spectrometry: Experimental Results Obtained with a Gaussian Beam and Analog Signal Processing

Transmission fluctuation spectrometry (TFS) is a method for the analysis of particle size distributions based on the statistical fluctuations of a transmission signal. Complete information on the PSD and particle concentration can be retrieved by a special transformation of the transmission signal, whereby the expectancy of the transmission square (ETS) is determined after the signal has been subjected to a procedure of spatial and temporal averaging. By varying the averaging parameters over a wide range, a spectrum of ETSs is obtained and introduced into a linear equation system, which yields the PSD. In the experimental realization presented here, variable temporal averaging is realized in the frequency domain with a series of low pass filters at different cutoff frequencies while spatial averaging inevitably occurs as the particles pass through a focused Gaussian beam of finite cross section. Experimental results on spherical particles (glass beads) and non‐spherical particles (SiC) are presented. The PSDs are resolved in 30 intervals within a particle size range from 1–1000 μm, employing a modified Chahine inversion algorithm. So far, the measurements are limited to moderate particle concentrations. Some influences affecting the measurements, especially for higher particle concentrations, are discussed in detail.     

Radiation heat transfer in axisymmetric quartz glass tubes

A mathematical model is proposed to describe the heat transfer in quartz glass axisymmetric tubes. Heat is transferred inside the glass by radiation and conduction. Scattering of thermal radiation inside the glass is ignored. At the boundaries of the tube the radiative intensity is specularly reflected. The spectral dependent radiative intensity and the temperature distribution inside the tube are determined. The model is applied to simulate the cooling process of a quartz glass tube. The calculated temperature is in agreement with that obtained from an experiment. Furthermore, steady-state temperature distributions in quartz glass tubes of different lengths have been determined.     

MILO中场不稳定性的非线性发展及混沌行为

 以磁绝缘传输线振荡器中电子运动和辐射场演化方程为基础，分析了场与电子相互作用过程中的不稳定性。这种不稳定性的发展导致场出现极限环振荡和混沌。在软非线性区域，辐射场表现为不连续的极限环振荡；在硬非线性区域，辐射场表现为连续的混沌行为。控制失谐量可加速或抑制这些不稳定态的出现。优化和调节参数可控制器件的运行状态, 获得较高的输出功率。