二维光子晶体功率分配与合成的仿真

利用平面波展开法,绘出了光子晶体的能带结构图,揭示了光子晶体能带结构的特点.在带隙结构中引入线缺陷,实现了对电磁波传播方向的控制.通过设计不同的线缺陷分布,实现了对电磁波传输能量的分配与合成.最终完成了对电磁波传播方向的控制和功率分配及合成的引导.采用Comsol Multiphysics软件对空气背景不同形状的介质光子晶体进行功率分配与合成的仿真,结果表明,在光子晶体中通过对线缺陷的设计,可实现功率的分配与合成.     

Laser-produced plasma He-alpha source for pulse radiography

Through the use of time and space integrated kiloelectronvolt （keV） spectroscopy, we investigate the thermal emission of plasma, which produces strong line emission from the titanium K shell （He-a at 4.7 keV and H-α at 4.9 keV）, created by laser. In order to optimize the conversion efficiency enhancement on titanium foils, the experiment is conducted under a variety of laser-driven intensity conditions. The X-ray emission intensity at 4.7 keV is measured and compared with prediction. The experimental result demonstrates that the solid Ti target laser-produced plasma （LPP） source has X-ray emission at 4.7 keV, which are all generated from electronic transitions in Ti ions at pulse width of 2.1 ns or 30 ps, the crudely evaluated He-α X-ray intensity appears to slightly increase with laser intensity enhancement, and the pre- pulse effect increases the conversion efficiency of the He-α X-ray. In addition, a 90-μm-thick Ti foil as a filter is used to transmit He-α X-ray at near 4.7 keV, creating a quasi-monochromatic transmission and greatly reducing the lower- and higher-energy background.     

Correction and analysis of lead content in soil by laser-induced breakdown spectroscopy

The laser-induced breakdown spectroscopy is used to analyze the lead content in soils. The analyzed spectral line profile is fitted by Lorentzian function for determining the background and the full-width at half-maximum （FWHM） intensity of spectral line. A self-absorption correction model based on the information of spectral broadening is introduced to calculate the true value of spectral line intensity, which refers to the elemental concentration. The results show that the background intensity obtained by spectral profile fitting is very effective and important due to removing the interference of spectral broadening, and a better precision of calibration analysis is acquired by correcting the self-absorption effect.     

3 ω线法测量液体热参数影响因素分析

首先给出基于谐波探测技术测量液体导热系数和热扩散系数的3ω线法的基本原理.采用实验和理论分析相结合的方法,分析了加热丝结构参数和自身热参数对温度波动和测量结果的影响.给出了加热丝直径和长度的合理范围.液体导热系数比较小时可以利用三次谐波的实部和虚部的交点测量液体的比热容.     

新大线同沟敷设热力分析

针对新大线同沟敷设管道,采用非结构化有限容积法,分析了不同的物性条件下,常温输送原油对加热输送原油的热力影响.     

A new gaseous detector — micro mesh gaseous structure

The structure and working principle of Micromegas （MICRO Mesh Gaseous Structure） is discussed. Some radiation sources of α and X rays are used to test this detector. The optimized electric-field intensity of the conversion gap is obtained. The transmission of electrons and the uniformity of the amplification gap are also presented. The energy resolution of the 5.9 keV peak is better than 27%.     

A Non-Zero Hadronic Elliptic Flow with a Vanished Partonic Elliptic Flow in a Coalescence Scenario

The elliptic flow of a hadron is calculated using a quark coalescence model based on the quark phase space distribution produced by a free streaming locally thermalized quark in a two-dimensional transverse plane at initial time. Without assuming the quark＇s elliptic flow, it is shown that the hadron obtains a non-zero elliptic flow in this model. The elliptic flow of the hadron is shown to be sensitive to both space momentum correlation and the hadron＇s internal structure. Quark number scaling is obtained only for some special cases.     

Re-entrant-Groove-Assisted VLS Growth of Boron Carbide Five-Fold Twinned Nanowires

We report a preferential growth of boron carbide nanowires with a five-fold twinned internal structure. The nanowires are found to grow catalytically via iron boron nanoparticles, but unusually the catalytic particle is in contact with the low-energy surfaces of boron carbide with V-shaped contact lines. We propose that this catalytical growth may be caused by preferential nucleation at the re-entrant grooves due to the twinning planes, followed by rapid spreading of atomic steps. This is consistent with the observed temperature dependence of the five-fold twinned nanowire growth.     

高浓度二氧化氯气体的在线检测研究

在40℃下,高浓度ClO2气体在盘管中迅速溶解于水中达到平衡,使用分光光度法检测平衡溶液的浓度,从而间接测定出ClO2气体的浓度。该方法可检测体积分数大于0.14%的ClO2,响应时间为15~30s,相对标准偏差为0.3%,与连续碘量法相比测定结果没有显著性差异(P<0.01),全过程中未使用化学试剂,操作简便,干扰小,适用于的高浓度ClO2气体在线检测。     

A SCREW DISLOCATION IN A THREE-PHASE COMPOSITE CYLINDER MODEL WITH INTERFACIAL RIGID LINES

The problem of the elastic interaction between a screw dislocation and a three-phase circular inclusion with interracial rigid lines （anti-cracks） is investigated. An efficient and concise method for the complex multiply connected region is developed, with which explicit series form solutions of the complex potentials in the matrix, and the interphase layer and inclusion regions are derived. Based on the complex potentials, the image force on the screw dislocation is then calculated by using the Peach-Koehler formula. The equilibrium position of the dislocation is discussed in detail for various rigid line geometries, interphase layer thicknesses and material property combinations. The main results show that the interracial rigid lines exert a significant perturbation effect on the motion of the screw dislocation near the circular inclusion surrounded by an interphase layer.