Determination of the uranium enrichment with the NaIGEM code

The traditional method used to non-destructively determine the uranium enrichment with an NaI detector is based on the “enrichment meter principle” (Progress report LA-4605-MS, Los Alamos National Laboratory, NNM, 1970, p. 19), which involves measuring the intensity of the 186 keV line of ²³⁵U by selecting two regions of interest for the peak and the background. This type of method suffers from several limitations, the most limiting of which are the impossibility to make wall thickness correction or to take the inference of foreign radioisotopes into account. The NaIGEM software (A guide for using NaIGEM code, version 1.5 for DOS and Windows, 2001; Nucl. Instr. and Meth. A 458 (2001) 196) was developed to overcome these limitations by calculating the 186 keV line intensity with a fitting procedure. The code was tested in different measurement conditions on the wide variety of certified samples, in particular, on reprocessed uranium and on depleted material with thick steel filters interposed between the source and the detector. The results are presented to illustrate the performance and limitations of the tested version (A guide for using NaIGEM code, version 1.5 for DOS and Windows, 2001). The general performance is good except in the case of low-enriched uranium in thick containers.     

东海盆地西南部地质特征与油气分布探讨

本文根据近3×10~4km地震和13口探井及其它地球物理、地质等方面资料,综合分析认为:东海盆地西南部与盆地其它部分在发育演化、构造运动、沉积环境等方面差异甚大。 盆地西南部(杭州湾—冲绳岛断裂以南地区)发育演化经历了断陷—坳陷—隆起—铺盖四个阶段。始新世末期的隆起在研究区演化史上有15～20Ma的沉积间断、剥蚀。这段历程,盆地其它部分未曾经历。其次是区内始新世末期抬升运动,致使始新统及以下老地层受剥蚀,仅始新统最大剥蚀量达1000m,这是盆地内绝无仅有的。第三是第三纪以海相沉积环境为主,特别在始新世,为海侵高潮,海城宽阔达8000km~2,这时盆地东北部正接受陆相沉积。研究区中部(北东向)可能存在超压泥岩及多套生油岩系,应为有利生油气区。研究区可能是盆地最有油气远景地区之一。     

济钢350m^3高炉高富氧生产技术

分析了济钢350m^3高炉高富氧对产量,理论燃烧温度,炉况顺行状况,焦比和生产效益的影响,高富氧可提高产量,但升高焦比和高炉理论燃烧温度,一定程度上影响高炉顺行,存在富氧效益最大化的适宜富氧率.高炉生产应低富氧高喷煤,根据钢目前的情况,富氧率经2%-3%为宜.     

Mesh‐independent p‐orthotropic enrichment using the generalized finite element method

This paper is aimed at presenting a simple yet effective procedure to implement a mesh‐independent p‐orthotropic enrichment in the generalized finite element method. The procedure is based on the observation that shape functions used in the GFEM can be constructed from polynomials defined in any co‐ordinate system regardless of the underlying mesh or type of element used. Numerical examples where the solution possesses boundary or internal layers are solved on coarse tetrahedral meshes with isotropic and the proposed p‐orthotropic enrichment. Copyright © 2002 John Wiley & Sons, Ltd.     

低阶煤煤层气富集模式初探

通过对美国粉河盆地以及我国铁法盆地煤层气富集规律的解剖,总结出影响低阶煤煤层气富集的关键因素是封堵,而构造、岩性和水动力是形成煤层气封堵的主要因素。同时提出了5种不同的煤层气富集模式,即背斜模式、构造—水动力模式、构造—岩性模式、岩性—水动力模式和岩性模式。     

邻菲罗啉-硫氰酸钾-水体系液固分离钴(Ⅱ)

当分析元素含量极低时,往往要求在测定之前辅以化学分离预富集手段以纯化富集待测物和除去干扰基体。实验利用邻菲罗啉和硫氰酸钾作为微痕量Co²⁺的络合剂,建立了一种液固体系分离富集微痕量Co²⁺的新方法。分别考察了邻菲罗啉溶液用量、硫氰酸钾溶液用量、酸度对分离效率的影响。结果表明,当体系中Co²⁺含量为100 μg时,控制体系pH=2~6,加入1.00 mL 1.5 g/L邻菲罗啉溶液、1.00 mL 0.1 mol/L硫氰酸钾溶液、1.00 mL 10 g/L EDTA溶液、1.00 mL 40 g/L硫脲溶液,震荡静置后,Co²⁺与邻菲罗啉、硫氰酸钾反应生成的离子缔合物定量沉淀到溶液底部,而Cd²⁺、Fe³⁺、Zn²⁺、Ni²⁺、Cu²⁺、Pb²⁺、Al³⁺、Ag⁺等离子仍留在水相中,从而实现了Co²⁺与这些离子的定量分离。方法成功用于合成水样中微痕量Co²⁺的定量分离,富集率在97.2%～98.6%之间。     

富集化合金层对铝阳极氧化膜的影响

在铝合金与氧化膜的界面的富集化合金层，对阳极氧化膜的局部和整体结构、膜的组成以及性能有重大影响。因此，对铝合金富集化进行预测很有必要。     

液膜法分离富集,测定水中微量锶

用乳状液膜体系对锶进行分离富集，该体系包括协同流动载体（ＰＭＢＰ，ＴＢＰ），表面活性剂（ＳＰＡＮ８０）增强剂（丙三醇）溶剂（正己烷）和内相（１．２ｍｏｌ／Ｌ的盐酸溶液），实验表明，在适宜的条件下，锶的富集效率可达９９．５％以上，而在此条件下许多共存离子，如Ｆｅ＾３＋，Ａｌ＾３＋，Ｃａ＾２＋，Ｍｇ＾２＋，Ｂａ＾２＋，Ｃｒ＾３＋，ＣＯ＾２＋，Ｎｉ＾２＋，Ｚｒ＾４＋，Ｃｕ＾２＋，Ｚｎ＾２＋，Ｐｂ＾２＋和     

NO emission of oxygen-enriched CH4/O2/N2 premixed flames under electric field

This work investigates the electric field effect on nitrogen oxide (NO) pollutant formation and emission composition of premixed flames in order to provide better insight on the mechanism of controlling the combustion process by electro-physical means. The present study aims to investigate experimentally the effect of radial DC electric field on premixed laminar methane flame. The electric field effect on flame shape, emission composition and NO emission index of flame is investigated experimentally under the action of direct-current electric field under varying equivalence ratio and level of oxygen enrichment. The results show that ionic wind effects cause the distortion in flame shape. The ionic wind effects diminish with increasing flow rate and level of oxygen enrichment. Minimal effects on NO are measured for flames under the influence of electric field and vanished as the level of oxygen enrichment is increased. This was well supported by the temperature profile measurement in the post flame gas showing no field-induced modification also. It seemed that the action of an electric field on a flame with a geometry that remains practically undeformed produces very minimal effect on pollutant emission.     

Fate of the chlorine and fluorine in a sub-bituminous coal during pyrolysis and gasification

The fate of the chlorine and fluorine present in a sub-bituminous coal from Indonesia during pyrolysis and gasification has been studied with fixed and entrained bed reactors. The rate profile for HCl evolved in the temperature programmed pyrolysis exhibits the main and shoulder peaks at 480 and 600 °C, respectively. Model experiments and subsequent Cl 2p XPS measurements show that HCl reacts with metal impurities and carbon active sites at 500 °C to be retained as inorganic and organic chlorine forms, from which HCl evolves again at elevated temperatures. It is suggested that the HCl observed in the coal pyrolysis may originate from the above-mentioned chlorine functionalities formed by secondary reactions involving the nascent char. In the CO₂ gasification of the 900 °C char at 1000 °C and 2.5 MPa, any measurable amounts of HCl and HF could not be detected even at a high conversion of 75 wt% (daf), suggesting the accumulation of these halogens in the residual char. When the coal is injected into an O₂-blown, entrained bed gasifier at 1200-1400 °C under 2.6 MPa, the partial oxidation proceeds to a larger extent at a higher O₂/coal ratio, whereas the chlorine and fluorine are enriched in the remaining char, and the extent of the enrichment at the latter stage of gasification is larger with the fluorine. The XPS measurements of the chars reveal the presence of the broad F 1 s peak, which can cover a wide range of binding energies attributable to inorganic and organic fluorine. The halogen enrichment during gasification is discussed in terms of secondary reactions of HCl and HF with char.