Ono–Kondo lattice model for high-pressure adsorption: Pure gases

Theoretical models for adsorption behavior are needed to develop optimal strategies for enhanced coalbed methane (CBM) recovery operations. Although several frameworks are available for describing this adsorption phenomenon, the Ono–Kondo (OK) lattice model offers several practical advantages in modeling supercritical, high-pressure adsorption systems.     

CVD人造金刚石核辐射探测器研究进展

金刚石探测器具有体积小、抗辐照能力强、时间响应快等优点,在核辐射领域应用优势显著。早期金刚石核辐射探测器均采用天然金刚石材料,化学气相沉积(chemical vapor deposition, CVD)金刚石人工合成技术的进步,极大地促进了金刚石核辐射探测器的发展与应用。本文从CVD人造金刚石材料入手,分析了制约金刚石探测器性能的杂质与缺陷、CVD金刚石的合成工艺、探测器级金刚石中杂质与缺陷的表征方法,并基于载流子迁移率与寿命乘积、探测器的电荷收集效率等性能指标,总结了CVD金刚石中的杂质与缺陷对探测器性能的影响规律,介绍了国外金刚石核辐射探测器的应用现状并展望了国内金刚石核辐射探测器的发展前景。     

微量杂质对苯并三氧化呋咱(BTF)感度影响研究

苯并三氧化呋咱(BTF)是一种由三叠氮三硝基苯(TATNB)经脱氮反应制得的零氧无氢炸药,90℃～120℃温度范围内动力学参数计算外推得到其贮存寿命大约是太安的1．5倍,桥丝感度与太安相当,需要的能量较小,并使发火的电压降低,其起爆性能、输出能量、机械感度、热安定性均     

对半导体杂质沉淀无损检测的若干结果

用XCD-H红外电视测微显微镜,通过无损检测来评价半导体材料与器件工艺的质量。本文仅对材料的完整性与芯片制造工艺导致杂质沉淀的问题进行讨论。     

硅片分凝除铁效应的研究

针对实用硅片研磨损伤层中的铁杂质玷污问题,本文探讨了Al-Fe-Si固溶体系的分凝效应,提出了一种热处理除铁的新工艺。实验样品用紫外光致荧光谱法进行了分析,并用扫描电镜X光能谱检测。结果表明,这一工艺使铁杂质含量明显下降。     

Effect of Various Impurities on the Hardness of NaCl Crystals

The hardness of NaCl crystal in the presence of mono, divalent and polyvalent ions were measured. Measurements were made in the indentation load range from 5 x 10^‐3 to 20 x 10^‐3 N. The measured data showed that there is an indentation size effect. Classical Meyer's law was used for the characterization of crystal hardness f NaCl. The Meyer index was found to be smaller than 2 indicating brittle material characteristic. The PRS model was also used for the determination of the load‐independent microhardness value. It was found that the crystal hardness of NaCl is chancing depending on the type of impurity and the concentration.     

The Influence of Impurities on Crystallization Kinetics of Sodium Chloride

The influence of impurities on the crystallization kinetics of NaCl was investigated in a fluidized bed crystallizer. The growth and dissolution rates were related to the supersaturation and impurity concentrations. The effect of different impurities on the growth rate of NaCl crystals can be divided into thermodynamic effects where the impurities influence the solubility and kinetic effects where the impurities will suppress the growth rate compared to the pure NaCl. A mathematical model describing crystal growth rates from aqueous solution as a function of impurity concentration is presented. The model explains impurity concentration effects on the crystal growth rate in terms of an impurity effectiveness factor and a Langmuir adsorption isotherm for the impurity.     

CaO杂质对铝型材厂工业污泥合成堇青石材料晶相结构及其含量影响

探讨原料组成对铝型材厂工业污泥合成堇青石材料的影响是非常重要的。研究目的有助于确定不同杂质在原料中允许的存在量,为选择其他原料提供可靠的依据。采用XRD法和SEM法分析各试样的晶相结构:用半定量分析方法确定各晶相的含量:用philipsX抪ertplus软件确定试样中各晶相结构参数。实验结果表明:CaO杂质含量从1.2~2.5%对合成堇青石有利:从2.5~2.8%堇青石含量开始下降:确定2.5%为CaO杂质最佳存在量,其对应的堇青石含量为91%。经plus软件确定结果:CaO杂质含量为1.2%时,其结构与单晶相同,晶胞参数变化很小:CaO含量从1.2~2.8%,其晶系由六方转变为四方结构,晶胞参数发生较大变化。镁铝尖晶石结构与晶胞参数变化较大,由单晶的立方结构转变为四方结构。     

Back-Scattered Electron Imaging of Microscopic Segregation in (Si,Ge) Single Crystals

Compositional inhomogeneities of (Si,Ge) single crystals grown by the radio frequency (RF) heated float zone technique have been studied using the back-scattered electron (BSE) mode of a scanning electron microscope. Numerical analysis of the images by Fast Fourier Transformation (FFT) showed that the number of spatial frequencies with substantial amplitudes is increased when investigating longitudinal sections of crystals containing dislocations instead of dislocation-free crystals. This can be attributed to different growth conditions in terms of super-cooling.     

Effect of dimensionality of a crystal lattice on the properties of a localized impurity

The changes of electron density due to the presence of a localized impurity in a crystal lattice are examined in dependence on the lattice dimensionality. The Koster–Slater impurity model developed for the case of a three-dimensional simple cubic lattice has been taken as the basis of examinations. Ordinary bound states, virtual bound states, and delocalized electron states are considered in each lattice case. For the delocalized states extended in a one-dimensional lattice the amplitude of the oscillatory changes of the electron density due to the impurity perturbation does not decrease with the distance from the impurity position, whereas for a two-dimensional lattice this amplitude decreases roughly proportionally to the reciprocal value of the square root of the distance from the impurity. Let us note that a well-known amplitude characterizing the decrease of the oscillatory change of the electron density in a three-dimensional system is proportional to the reciprocal value of the third power of the distance from the impurity position. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 79: 57–74, 2000