Electron Acoustic Solitons

Electron acoustic solitons in collisionless and weakly relativistic plasmas are studied. The Krylov–Bogoliubov–Mitropolsky perturbative technique is employed to obtain the nonlinear Schrodinger wave equation. We have numerically investigated modulational instability for different values of the streaming velocity. Graphs have been plotted to see the change in amplitude and inverse width by varying different plasma parameters.     

多群中子散射角分布L阶截断出负的改进

蒙特卡罗方法或离散纵标法模拟多群中子输运方程，散射角分布通常按Legendre级数展开，取L阶截断近似。当L较小时，近似角分布在[-1，1]定义域的多处出负，面积不归一，进而导致非物理解。文章针对这一问题，利用矩和Legendre系数等价关系，给出离散广义Gauss求积组，并用该求积组作节点构造等概率阶梯函数，逼近实际角分布，从而消除非物理解。计算取得了与实验和连续截面蒙特卡罗MCNP程序一致的结果。     

Surface Plasmon Resonance Enhanced Scattering of Au Colloidal Nanoparticles

Abstract Suspended gold nanoparticles have been synthesized via electrochemical method.The strongest resonance scattering peak is at 485 nm, which results from the surface plasmonresonance. When the excited wavelength is at 242 nm (12.4×10~(14) Hz), there have been a 1/2fraction frequency scattering peak at 485 nm (1/2×12.4×10~(14) Hz) and a 1/3 fraction frequencyscattering peak at 726 nm (1/3×12.4×10~(14) Hz) displayed. Emission spectra with different particlediameters were compared, the intensity of scattering light increases with the particle size. Thefrequency-dependent scattering average cross section of small particle was calculated from Mietheory. The model calculation is in agreement with the experimental results.     

低能区(e,2e)反应的多重散射理论

对文献［７］发展的（ｅ，２ｅ）反应多重散射理论做了改进用得到的波函数计算了能量为５４４ｅＶ的（ｅ，２ｅ）反应的截面，结果表明改进后的多重散射理论与实验符合较好     

声表面波谐振器无源无线传感虚拟仪器系统

分析了在通用硬件平台上结合软件设计的声表面波谐振器无源无线传感虚拟仪器系统。该系统通过设计虚拟仪器实现部分硬件功能,控制闭环系统实现自动检测,并采用数字信号处理方法提高检测系统的精度,从而避免了通常的复杂硬件系统,降低硬件成本,并使检测更灵活。本文介绍了设计原理和系统构成,并对系统的误差进行了分析。实验表明:该仪器系统能够达到5m的无线检测距离。     

The effects of refractive index heterogeneity within kidney tissue on multiphoton fluorescence excitation microscopy

Although multiphoton fluorescence excitation microscopy has improved the depth at which useful fluorescence images can be collected in biological tissues, the reach of multiphoton fluorescence excitation microscopy is nonetheless limited by tissue scattering and spherical aberration. Scattering can be reduced in fixed samples by mounting in a medium whose refractive index closely matches that of the fixed material. Using optical 'clearing', the effects of refractive index heterogeneity on signal attenuation with depth are investigated. Quantitative measurements show that by mounting kidney tissue in a high refractive index medium, less than 50% of signal attenuates in 100 μm of depth.     

Frequency-dependent dynamic effective properties of porous materials

The frequency-dependent dynamic effective properties (phase velocity, attenuation and elastic modulus) of porous materials are studied numerically. The coherent plane longitudinal and shear wave equations, which are obtained by averaging on the multiple scattering fields, are used to evaluate the frequency-dependent dynamic effective properties of a porous material. It is found that the prediction of the dynamic effective properties includes the size effects of voids which are not included in most prediction of the traditional static effective properties. The prediction of the dynamic effective elastic modulus at a relatively low frequency range is compared with that of the traditional static effective elastic modulus, and the dynamic effective elastic modulus is found to be very close to the Hashin-Shtrikman upper bound.     

放射性同位素XRF技术中一种与“特散比”法等效的新方法

在一定的条件下,待测元素特征X射线和康普顿散射强度比值,与待测元素特征X射线强度和带吸收滤片所测量的强度比值之间有着简单的双曲函数关系。利用这一函数关系,很容易在单道携带式放射性同位素X射线荧光分析仪上实现“特散比”法改善基体效应。用这种方法所得到的分析结果和用“特散比”法得到的分析结果,二者吻合很好,而且不需要增加任何设备,节省了测量时间和成本。已经测量了几种类型的锡矿样品和某些铜矿样品。     

输气管道音波泄漏检测技术的研究

输气管道泄漏的检测与定位，是管道维护及管道安全运行的重要研究课题.将音波检测方法应用于输气管道的泄漏检测，介绍了音波泄漏检测与定位的基本原理.阐述了采用相关分析法进行泄漏定位的数据处理方法.设计完成了传感器信号提取、模拟信号滤波和A/D数据转换等硬件电路.在单片机上移植Small Rtos51嵌入式实时操作系统，有效管理检测任务，实现信号采集、数据传输和异常情况处理，从而提高了系统的实时性和可靠性.通过搭建输气管道试验平台，对试验数据采集、处理及仿真，论证了音波检测方法应用于输气管道泄漏检测的可行性.     

Integrated data analysis on the electron temperature profile of HL-2A with the Bayesian probability inference method

Data analysis on tokamak plasmas is mainly based on various diagnostic systems, which are usually modularized and independent of each other. This leads to a large amount of data not being fully and effectively exploited so that it is not conducive to revealing the deep physical mechanism. In this work, Bayesian probability inference with machine learning methods have been applied to the electron cyclotron emission and Thomson scattering diagnostic systems on HL-2A/2M, and the effects of integrated data analysis (IDA) on the electron temperature of HL-2A with Bayesian probability inference are demonstrated. A program is developed to infer the whole electron temperature profile with a confidence interval, and the program can be applied in online analysis. The IDA results show that the full profile of the electron temperature can be obtained and the diagnostic information is more comprehensive and abundant with IDA. The inference models for electron temperature analysis are established and the developed programs will serve as an experimental data analysis tool for HL-2A/2M in the near future.