The Thermal Properties and Firing Characteristics of Zr/KClO4 Priming Compositions Containing Graphite,Fe2O3 and Al2O3 additives

Thermal decomposition of Zr/KClO₄ priming compositions containing different concentration of additives, such as graphite, Fe₂O₃ and Al₂O₃ have been studied by DSC/TG techniques. The firing characteristics of these primer mixtures have also been examined by Bruceton test and by adiabatic calorimeter. The results of these experiments suggest that strong interaction has been occurred between KClO₄ and Fe₂O₃ in the solid state. This revised version was published online in July 2006 with corrections to the Cover Date.     

A Low-temperature Automated Adiabatic Calorimeter Heat Capacities of High-purity Graphite and Polystyrene

A computerized adiabatic calorimeter for heat capacity measurements in the temperature range 80–400 K has been constructed. The sample cell of the calorimeter, which is about 50 cm³ in internal volume, is equipped with a platinum resistance thermometer and surrounded by an adiabatic shield and a guard shield. Two sets of 6-junction chromel-copel thermocouples are mounted between the cell and the shields to indicate the temperature differences between them. The adiabatic conditions of the cell are automatically controlled by two sets of temperature controller. The reliability of the calorimeter was verified through heat capacity measurements on the standard reference material α-Al₂O₃. The results agreed well with those of the National Bureau of Standards (NBS): within ±0.2% throughout the whole temperature region. The heat capacities of high-purity graphite and polystyrene were precisely measured in the interval 260–370 K by using the above-mentioned calorimeter. The results were tabulated and plotted and the thermal behavior of the two materials was discussed in detail. Polynomial expressions for calculation of the heat capacities of the two substances are presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Oxyreactive Thermal Analysis of Dispersed Organic Matter, Kerogen and Carbonization Products A Tool for Investigation of the Heated Rock Masses

This paper presents the results of oxyreactive thermal analyses of organic matter in rocks, heated naturally during diagenetic to metamorphic processes. During the experiments we traced the reactions in the temperature range up to 900°C, it means from the very beginning of diagenetic transformations to the highest real temperatures acting in the Earth's crust as a solid phase. The results showed that TA could be a tool for the reconstruction of thermal regime in natural coal-bearing systems. This revised version was published online in August 2006 with corrections to the Cover Date.     

Particle Deposition in Porous Media: Analysis of Hydrodynamic and Weak Inertial Effects

We have studied the transport and capture of non-Brownian particles in porous media, when the particles are mainly submitted to hydrodynamic and weak inertial effects. Visualization experiments have been performed using several models of porous media which consist of transparent etched networks of interconnected channels. Typical particle deposits have been observed at the corners of the grains of the porous medium. Their shape and their orientation were dependent on flow rate and on the anisotropy of the flow field. A trajectory analysis model has been applied to a porous medium made of a doubly periodic array of rectangular grains very close to the experimental model. This numerical model has been used to localize particle deposits and to determine particle capture efficiency on the grains over a range of low Stokes numbers, grain aspect ratios and flow-field anisotropy ratios. The results have been interpreted in terms of shape of particle deposits and compared successfully to experimental observations.     

Research on the particle dispersion in the particulate two-phase round jet

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Motion of a Colloidal Sphere Covered by a Layer of Adsorbed Polymers Normal to a Plane Surface

A combined analytical–numerical study is presented for the slow motion of a spherical particle coated with a layer of adsorbed polymers perpendicular to an infinite plane, which can be either a solid wall or a free surface. The Reynolds number is assumed to be vanishingly small, and the thickness of the surface polymer layer is assumed to be much smaller than the particle radius and the spacing between the particle and the plane boundary. A method of matched asymptotic expansions in a small parameter λ incorporated with a boundary collocation technique is used to solve the creeping flow equations inside and outside the adsorbed polymer layer, where λ is the ratio of the characteristic thickness of the polymer layer to the particle radius. The results for the hydrodynamic force exerted on the particle in a resistance problem and for the particle velocity in a mobility problem are expressed in terms of the effective hydrodynamic thickness (L) of the polymer layer, which is accurate to O(λ²). The O(λ) term forLnormalized by its value in the absence of the plane boundary is found to be independent of the polymer segment distribution and the volume fraction of the segments. The O(λ²) term forL, however, is a sensitive function of the polymer segment distribution and the volume fraction of the segments. In general, the boundary effects on the motion of a polymer-coated particle can be quite significant.     

溶剂萃取石墨炉原子吸收光谱测定盐卤中痕量铷

采用石墨炉原子吸收光谱（ＧＦＡＡＳ）研究盐卤中铷的原子化行为和机理,建立了热解石墨管,ＫＮＯ３－ＮＨ４ＮＯ３基体改进剂,１８－冠－６,溴百里香酚蓝,氯仿萃取分离ＧＦＡＡＳ测定盐卤铷的方法。用于测定盐卤中痕量铷,特征质量１．１×１０＾－１０ｇ／０．００４４,加标回收率８９％￣１１０％;相对标准偏差６．２８％（ｎ＝１３）。     

两束脉冲激光在级联的三能级系统中的传播

利用密度矩阵方程和麦克斯韦传播方程的耦合考虑激光脉冲的横向效应,在柱对称的条件下,研究了两束脉冲在级联系统中的共振传播,考察了脉冲在光学厚介质中的时空演化过程。数值计算中考虑了两个能级的自发辐射速度,给出了脉能量的空间演化及电熟粒子在空间的分布。     

用谱方法数值模拟槽道内的气固两相流动

在数值模拟领域内,谱方法具有收敛快、分辨率高和精度高的优点．谱方法处理边界方便,随着数值方法的改善和计算机的发展,它在数值模拟中的作用愈加重要．这里采用谱方法数值求解三维Ｎ—Ｓ方程,用这一方法计算了直槽道内流体的流动．计算得到的层流和湍流结果与理论结果符合地较好．在此基础之上进一步模拟了几种不同槽道内的三维粘性流体层流流动,特别在弯曲槽道内的流动计算中,发展了源项处理方法,正确地反映了弯曲固壁对流体流动的影响．通过对湍流计算获得的脉动速度场的统计可以得到湍流运动的许多统计量,正确地反映了湍流运动的特征,说明可以用模拟得到的流场来代替真实的流场．进行了气固两相流动的研究,由直接模拟得到的流体瞬时速度场对固体粒子的作用进行了粒子运动的模拟计算,得到了颗粒在真实流场中运动的浓度,轨道等有用信息和运动特性,得到了令人鼓舞的结果．     

返波型行波电子直线加速结构的理论研究

比较了行波与驻波两种工作方式以及前向波与返波型行波的不同特点;研究了返波型行波电子直线加速结构的工作特性;并针对返波型行波电子直线加速结构的特点,进行工作模式的选择;对工作频率为2856MHz,3π/4模的返波加速结构进行了优化设计;研究了带聚束段的返波型行波加速管的纵向与横向粒子动力学问题;为海关大型集装箱在线检测用加速器设计了一根9MeV返波型行波加速管,并与采用盘荷波导结构的加速管进行了对比.研究结果表明,返波型行波电子直线加速结构具有一定的优势,它把鼻锥型加速结构分流阻抗高及盘荷波导行波工作方式填充时间短,工作稳定性好等优点结合起来,性能明显优越.