激光拉曼光谱法测定天然气组成标准研究

进行了天然气组成分析-激光拉曼光谱法标准化研究,探讨了激光拉曼天然气组成分析方法标准化的可行性。采用激光拉曼光谱进行天然气组成分析,无需将天然气中各组分分离便可实现多组分同步检测,减少分析时长,提高测量的实时性,实现快速分析,通过国内外激光拉曼天然气分析方法和标准的研究和实验,掌握了国内外激光拉曼天然气分析方法技术现状及发展方向,积累了激光拉曼天然气分析试验数据,结果表明激光拉曼天然气分析具有可快速检测(10 s)、连续记录和操作简单的优点,适用于天然气录井、井站、集气站原料气气质分析和天然气净化处理中过程控制中实时快速获取气质数据,建议制定激光拉曼光谱天然气分析方法标准,测量组分为CO₂,N₂,H₂S,CH₄,C₂H₆,C₃H₈,测量范围分别为：CH₄：75%~99.9%,C₂H₆：0.005%~20%,C₃H₈：0.005%~10%,H₂S：0.001 5%~10%,N₂：0.02%~10%,CO₂：0.01%~10%(上述浓度均为摩尔分数),为上游领域天然气勘探开发及过程控制服务。     

Cross sections for (d–t) neutron interaction with germanium isotopes

The cross sections for (n,x)$(n,x)$ reactions with Ge isotopes were measured at (d–t) neutron energies around 14 MeV with the activation technique using metal discs of natural composition. Calculations of detector efficiency, incident neutron spectrum and correction factors were performed with the Monte Carlo technique (MCNP4C code). Cross sections data are presented for ⁷⁰Ge(n,2n$n,2n$)⁶⁹Ge, ⁷⁴Ge(n,α$n,\alpha$)^71mZn, ⁷⁶Ge(n,2n$n,2n$)^75(m + g)Ge, ⁷⁰Ge(n,p$n,p$)⁷⁰Ga and ⁷²Ge(n,2n$n,2n$)^71gGe reactions. The cross section results for ⁷²Ge(n,2n$n,2n$)^71gGe reaction were reported for the first time. Some other cross sections were obtained with higher precision, including the ⁷⁰Ge(n,p$n,p$)⁷⁰Ga reaction. Theoretical calculations of excitation functions were performed with the TALYS-1.0 code and compared with the experimental cross section values. Data were included in the EXFOR database.     

Natural radioactivity and radon exhalation rates in building materials used in Egypt

Natural and fabricated building materials commonly used in Egypt were surveyed for both natural radionuclides content and radon exhalation rate. These include raw as well as construction products. Concentration of natural radionuclides in all samples were determined by γ-ray spectroscopy with HPGe detector. For Radon exhalation rate measurements of fabricated samples, the seal can-technique has been applied using CR-39 plastic track detectors. The radiation hazard indices of the total natural radioactivity in the studied samples were estimated. The results were compared with the corresponding results of different countries and were found to be lying within the average world values. Radon exhalation rate in the studied samples varied between 197 (cement brick) and 907 mBq m⁻² h⁻¹ (blast furnace slag cement). The results of this survey suggest that, using blast furnace slag cement for pre-coating the internal walls of buildings in the Urban region of Egypt is discouraged and the replacement of clay brick by cement brick will be more healthy for the public.     

氟代吡啶阳离子的理论研究

利用量子化学密度泛函理论B3LYP方法及 6 31G(d ,p)、6 311G(d ,p)、6 31+G(d ,p)和 6 311+G(d ,p)基组对五氟代吡啶、2 ,6 二氟代吡啶和 2 氟代吡啶分子的阳离子进行了计算研究 .B3LYP构型优化和频率分析计算结果表明这三种氟代吡啶阳离子的结构分别具有C2v、C2v和Cs 对称性 ,电子基态分别为2 A2 、2 A2 和2 A″ .对离子和分子的计算构型做了比较 .利用B3LYP方法和不同的基组对这三种阳离子及其分子进行了自然布居分析计算 .用B3LYP方法对这三种阳离子 (自由基 )中的超精细结构进行了计算 ,对五氟代吡啶、2 ,6 二氟代吡啶和2 氟代吡啶分子的垂直电离势和绝热电离势进行了计算 ,与实验值符合得很好     

Natural convection heat transfer at reduced pressures

This paper experimentally studies the natural convection heat transfer characteristics on horizontal and vertical plates at pressures lower than atmospheric value. Eight different pressures ranging from 10Pa to 101.325kPa, and three heating loads were used in the experiments. It is found that natural convection heat transfer characteristics at reduced pressures are independent of the plate arrangements and present different behaviors in two pressure ranges, 10Pa < p < 1000Pa and p > 1000Pa. The experimental heat transfer results are correlated into a non-dimensional equation to help the thermal design of stratosphere aircrafts and airborne equipment.     

Experimental study of transient heat transfer characteristics of single-phase natural convection in multidimensional porous bed with volumetric heat generation

Natural convection in an internally heated porous bed of height and diameter of 450 mm and 500 mm, respectively, and superposed with the fluid layer has been experimentally investigated. The onset of natural convection in the bed is indicated by change in the rate of temperature rise within the bed. An empirical model based on local Nusselt number and local Rayleigh number has been developed. A comparison of the present model with the models in literature is made to draw out the differences between the local heat transfer of large multidimensional beds and the average heat transfer of small beds.     

Analytical and numerical studies for Seiches in a closed basin with bottom friction

A standing wave oscillation in a closed basin, known as a seiche, could cause destruction when its period matches the period of another wave generated by external forces such as wind, quakes, or abrupt changes in atmospheric pressure. It is due to the resonance phenomena that allow waves to have higher amplitude and greater energy, resulting in damages around the area. One condition that might restrict the resonance from occurring is when the bottom friction is present. Therefore, a modified mathematical model based on the shallow water equations will be used in this paper to investigate resonance phenomena in closed basins and to analyze the effects of bottom friction on the phenomena. The study will be conducted for several closed basin shapes. The model will be solved analytically and numerically in order to determine the natural resonant period of the basin, which is the period that can generate a resonance. The computational scheme proposed to solve the model is developed using the staggered grid finite volume method. The numerical scheme will be validated by comparing its results with the analytical solutions. As a result of the comparison, a rather excellent compatibility between the two results is achieved. Furthermore, the impacts that the friction coefficient has on the resonance phenomena are evaluated. It is observed that in the prevention of resonances, the bottom friction provides the best performance in the rectangular type while functioning the least efficient in the triangular basin. In addition, non-linearity effect as one of other factors that provide wave restriction is also considered and studied to compare its effect with the bottom friction effect on preventing resonance.     

A combinative technique to recognise and discriminate turquoise stone

This study attempts to identify and categorize turquoise stone based on its compounds and major factors that introduces its color change. Turquoise samples which are investigated in this study have been collected from the most important turquoise mines in world. Combination of two different analysis methods assists this study for scrutinizing turquoise constituents and effects of their percent on its color change. The application of infrared spectroscopy and X-Ray Fluorescence (XRF) methods can reveal the true composition of various “turquoise” samples in range of blue color to green color. Whereas the first technique (FTIR) is especially capable in diff ;erentiating between natural samples and fake or simulant stones for prevent of jobbery. Changing percent of four compounds including CuO, Al₂O₃, P₂O₅ and Fe₂O₃, is the most effective factors of varying color in turquoise stones. In conclusion, blue turquoise stone contains great percent of light elements or blue color factors in comparison to green turquoise stone which contains jorum of heavy element.     

原子光谱线增宽的原因

本文从理论上给出了原子光谱线增宽的几种原因 ,即 :①自然线宽 ,它是原子的内禀特性 (即在跃迁中所涉及到的能级的特性 ) ;②多普勒增宽 ,它是原子无规则热运动的结果 ;③碰撞增宽 ,它是原子间相互作用的结果。并对这几种原因分别给出了数量级上的估算。对原子光谱的测定具有参考意义。