砷化镓晶片表面损伤层分析

采用ＴＥＭ观测与Ｘ射线双晶回摆曲线检测化学腐蚀逐层剥离深度相结合的方法，分析了ＳＩ－ＧａＡｓ晶片由切、磨、抛加工所引入的损伤层深度。比较两种方法测量结果上的差异，得出了ＴＥＭ观测到的只是晶片损伤层厚度，而Ｘ射线双晶回摆回线检测化学腐蚀逐层剥离所得的深度是晶片损伤及其形成应力区的最度的结论。     

用Simultix10X射线荧光光谱仪分析高合金钢

本文叙述了用Ｒｉｇａｋｕ Ｓｉｍｕｌｔｉｘ１０型多道Ｘ射线荧光光谱仪分析钢铁及合金时，用理学软件中的Ｌ－Ｔ，ＤＪ，ＪＩＳ三种模式计算相应理论校正系数，分别进行了共存元素之间基体吸收－增强效应的校正，并用三种模式对不同基体钢铁试样进行了分析比较。     

含Sn高磁感(Hi-B)取向硅钢脱碳退火板面氧化层研究

应用Ｘ射线荧光能谱、红外线吸收光谱、Ｘ射线衍射和Ｘ射光子能谱、俄歇电子能谱等手段，研究了含Ｓｎ－Ｈｉ－Ｂ硅钢脱碳退火板面“膜”的成分及其分布。证实了“膜”即氧化层，分析了在受上力时“膜”即剥离的原因。文中还给了了Ｓｎ－Ｈｉ－Ｂ硅钢板脱碳退火后表面氧化量的宏观度量方法和几种工艺条件下所形成的诸氧化物的含量。     

铝、硅质耐火材料的X射线荧光光谱分析

采用Ｘ射线荧光光谱仪测定铝、硅质耐火材料，研究了系统制样方法及基体吸收－增强效应的校正，还研究了测定精度及制样精度，拓展了铝、硅质耐火材料的分析范围。     

Co－Cr_3C_2合金与WC润湿性的观察和分析

采用实况采相观察了Ｃｏ－Ｃｒ３Ｃ２合金与ＷＣ的润湿现象，采用ＪＣＸＡ－７３３型电子探针显微分析仪和３０１４型Ｘ射线衍射仪研究了Ｃｏ－Ｃｒ３Ｃ２合金熔渗ＷＣ所形成的组织，为ＷＣ－Ｃｏ合金中添加Ｃｒ３Ｃ２的作用机理提供解释依据。     

电解质的组成对铝电解中电渗的影响

通过试验考察了氧化铝浓度、分子比及氟化镁含量对 电解电渗的影响，并通过电子探讨和Ｘ－射线衍射分析了电渗的物质，电渗的深 度。结果表明：电渗的主要物质是钠氟化合物，随着氧化铝浓度及氟化镁含量的增加，电渗的度及电渗的物质量增加当冰晶石分子比达到２．０时，电渗的深度急剧增加。     

Co—Cr3C2合金与WC润湿性的观察和分析

采用实况采相观察了Ｃｏ－Ｃｒ３Ｃ２合金与ＷＣ的润湿现象，采用ＪＣＸＡ－７３３型电子探针显微分析仪和３０１４型Ｘ射线衍射仪研究了Ｃｏ－Ｃｒ３Ｃ２合金熔渗ＷＣ所形成的组织，为ＷＣ－Ｃｏ合金中添加Ｃｒ３Ｃ２的作用机理提供解释依据。     

X射线Φ扫描及其在高温超导薄膜分析中的应用

Ｘ射线φ扫描及其在高温超导薄膜分析中的应用常世安，陈岗峰，马平，杨坚，古宏伟，袁冠森（北京有色金属研究总院１０００８８）关键词：Ｘ射线衍射，高温超导薄膜Ｘ射线衍射仪的常规θ－２θ扫描只能对平行于试样表面特定晶面进行检测￣［１］．而无法区别是单晶、外延...     

利用γ射线连续测量料位

利用γ射线穿透性强 ,同时又可被介质吸收的特点 ,通过电子电路转换放大计数管吸收的穿透容器的γ射线 ,得到不同剂量γ射线所对应的电信号 ,运用以单片机为基础开发的智能仪表采集此信号 ,经运算显示不同剂量γ射线对应的容器内物料高度百分比值 ,并输出相应的标准信号 ,为闭环控制提供依据。     

机械合金化制备Ni—Mo非晶合金的研究

本文采用机械合金化方法制备了ＮｉｘＭｏ１００－ｘ（Ｘ＝８０，７０，６２，５５，４０）合金，并采用Ｘ射线衍射研究了球磨过程中粉末结构的变化。结果表明，当Ｘ≥７０时得到了镍的固溶体，在Ｘ≤７０时得到了镍的固溶体，在Ｘ≤６２时得到了部分非晶合金。通过ＤＳＣ差热分析研究了Ｎｉ６２Ｍｏ３８部分非晶合金的晶化行为，并从理论上探讨了该合金体系形成完全非晶合金的可能性。     

唐钢RH钢包混匀时间及流场模拟计算与分析

研究了真空度、提升气体量和吹气孔位置对RH钢水混匀时间的影响,模拟了钢包流场情况。试验结果表明:提高RH系统真空度、增加RH提升气体量或增大气体的吹入深度均可减小混匀时间;唐钢RH精炼过程中无死区存在,在相应的混匀时间内可以实现整包钢水成分和温度的均匀;合理控制真空度、提升气体量和浸渍管插入深度有利于稳定出站钢水碳含量,提高Al2O3夹杂物的去除率。     

Radiation emission from the ＂Rhodotron-TT200＂ cavity

In this paper, the X-rays emitted from the Rhodotron-TT200 cavity have been studied in depth. We found that the Bremsstrahlung interaction is the only contribution of X-ray generation important to safety. The X-ray dose rate in the Rhodotron vault is calc     

Lodged bullet or bullet penetration? Re-entry of a projectile and pseudo-shot

In an extended suicide an 11-year-old boy was killed by two shots into the back. In spite of corresponding entry and exit points one of the projectiles was found inside the body. By laying open the respective bullet track, examination of the deformations of the bullet, on which a total of three ricochet points were identified, and a second visit to the scene both the order in which the shots were fired and the reason why one of the projectiles was lodged inside the body, although there was an exit point, could be clarified: On firing the second shot the victim had been lying on the wooden threshold of a door, from which the projectile ricochetted. The terms "reentry" and "pseudo exit point" are discussed. The retention of the bullet in the depth of an alleged exit wound emphasizes the importance of post-mortal X-ray examinations.     

A simple costing of three methods used to prepare endoscopy equipment

The paper describes a DRIM-1 X-ray monitor which directly measures and records the product of an absorbed (exposure) dose and the actual area of X-ray beam onto the outside surface of the depth diaphragm (cGy.cm2). The principle of action of the device is based on the measurement of the charge coming from the detecting unit--a preamplifier ionization chamber. The device may be used to control the time-stability of a radiation signal in the X-ray apparatus.     

Optimisation of a polarised X-ray source for the in vivo measurement of platinum in head and neck tumours

There is a continuing need to improve the understanding of kinetics of platinum-based chemotherapeutic agents, such as cisplatin and paraplatin. Although these agents demonstrate highly effective anti-cancer activity, they also have associated, often dose-limiting, side-effects such as nephrotoxocity. In vivo X-ray fluorescence (XRF) has been proven to be a suitable technique for measuring the uptake of these agents in tumour and critical organs, but radioisotope based systems have not found their way into routine clinical use due to their rapid increase in minimum detection limit (MDL) with depth. Polarised X-rays offer a solution to this problem by reducing the scattered background, which not only reduces the MDL, but also allows the intensity of the source to be increased without saturating the detector electronics. This paper describes the development and optimisation of a polarised XRF system for in vivo measurement of platinum in head and neck tumours, whose response to cisplatin is often unpredictable. The polarised X-ray source comprises a clinical X-ray therapy unit (the Pantak DXT-300) with removable purpose-built collimators. Optimisation studies have concentrated upon the operating voltage, polariser material and additional filtering. The optimum voltage was found to lie within the range 200-300 kV for all polarising materials. There was no significant difference using copper, aluminium or iron as the polariser. Increasing the additional filtering improved the MDL for a preset number of counts, but decreased the count-rate significantly, resulting in unacceptably long counting times. An MDL of 9 ppm was achieved for a phantom depth of 2 cm, using a copper polariser, 0.25 mm of tin filtering and an operating voltage of 220 kV. TLD measurements showed that the corresponding skin dose was 6 mGy. These results indicate a factor of improvement in the MDL from the previous 99mTc system, for a factor of two lower skin dose. The detection limit achieved is the lowest reported to date, and is considered adequate for a comprehensive patient study. It is anticipated that this will yield better information and the pharmacokinetics of platinum compounds and will lead to optimisation of both chemo and radiotherapy treatment. Additionally this technique can be easily integrated into any radiotherapy based department.     

Three-Dimensional Large Deformation FE Analysis of Square Footings in Two-Layered Clays

In strong over soft two-layered clays, there is a potential for the footing to experience a punch-through failure, where the footing penetrates a large distance at a short time after the initial peak resistance is reached. Three-dimensional (3D) large deformation finite-element analyses using 3D RITSS method were conducted to simulate the penetration responses of square footings in strong over soft clays. The effects of surface soil heave and soil layer interface deformation during footing penetration were studied in weightless soils. Fitted equations were proposed to express the footing capacity response against the penetration depth. Based on the fitted equations, formulas to calculate footing peak bearing factor and the corresponding penetration depth were developed. The peak footing capacity factor and the corresponding penetration depth increases with the increasing of soil layer strength ratio, relative top soil layer thickness and soil weight factor, thus the potential of punch-through failure was reduced accordingly. It was also found that the soil weight effect can be a simple surcharge based on the formula developed in the weightless soil. Design charts for the peak footing capacity factor and the corresponding penetration depth were developed.     

对线材表面脱碳层深度变化规律的研究

根据邢钢线材表面脱碳层深度统计数据的变化规律,对脱碳层深度的变化情况进行了研究。要保证邢钢线材产品冷镦性能稳定,钢坯表面脱碳层深度必须控制在0．9mm以下。     

Reduction of platelet surface GPIb expression induced by polymorphonuclear leukocytes

1. There are few data regarding the accuracy of Hologic QDR-1000W dual-energy X-ray absorptiometry for the measurement of body composition. In two studies, one in an in vitro experimental system using oil and water mixtures and the other in samples of pork meat, the effect of depth and tissue thickness on the measured composition was assessed. In the latter study the measured fat mass was compared with that measured by direct analysis. 2. All data indicated a trend in the measured fat mass with depth, such that more fat was measured at extremes of depth (< 10 cm and > 25 cm) than at intermediate depths. 3. In samples of meat weighing approximately 55 kg, dual X-ray absorptiometry significantly under-estimated the absolute fat mass compared with direct analysis (mean 20.4 +/- 1.65%) by 5-8% or 1-4 kg of fat. 4. These findings are of direct relevance to both clinical and research work using this technique to measure body composition, in particular in circumstances in which changes in body composition and/or tissue thickness are anticipated.     

Bronchopulmonary dysplasia: correlation of radiographic and clinical findings

BACKGROUND AND PURPOSE: Abnormalities of the chest wall have been described in bronchopulmonary dysplasia (BPD). Clinical, radiographic and pulmonary function variables were evaluated in 1-year-old children ventilated because of neonatal lung disease in order to quantify these thoracic changes and to evaluate the lung disease. METHODS: The pulmonary status of 51 infants with neonatal lung disease requiring artificial ventilation was reevaluated clinically and radiographically at the age of 1 year. Twenty-two of these infants had developed BPD. Thoracic depth and width were measured clinically and on chest X-ray. The Toce score evaluated the presence of cardiomegaly, hyperinflation, emphysema and interstitial lung disease. Lung function was measured after sedation using previously reported methods. In BPD patients, Toce score and lung function were determined and compared at 1 month and at 1 year of age. RESULTS: In BPD patients, chest depth was significantly smaller when measured clinically as well as on chest radiograph (P < 0.05; Mann-Whitney U-test). There was a statistically significant correlation between chest depth measured clinically and on chest X-ray. Toce score was significantly higher in BPD patients (P < 0.05). In BPD patients intersitial abnormalities and decreased lung compliance were more frequent at the age of 1 month than at the age of 1 year. At the age of 1 year, hyperinflation was more frequent and at that time increased airway resistance was still noted. Thus the type of X-ray abnormality reflects the type of lung function disturbance. CONCLUSION: The flatness of the chest is most likely a consequence of the long-standing lung function abnormalities.     

Design Method of Time-Dependent Local Scour at Circular Bridge Pier

A reliable prediction of local scour depth related to hydrological characteristics such as peak discharge, and time corresponding to the equilibrium scour depth is essential for the efficient design of bridge pier foundation. In this paper, a design method to predict the local scour depth with time is proposed. An experimental program was carried out using a cylindrical pier placed in uniform beds under clear-water flows. The pier scour depth was calculated on the basis of a sediment transport equation. Equilibrium local scour depth is reached when the bed-shear stress tends to critical bed-shear stress in the scour hole. Hence, changes to bed-shear stress at the circular bridge pier should be incorporated in the sediment transport theory. The proposed method follows experimental data of various sources.