复合超细丙纶及应用

对国内外细旦丙纶的开发和发展进行了介绍，阐述了单丝纤度为０．１～０．５ｄｔｅｘ的复合超细丙纶的制造方法、原材料规格、复合剥离技术以及产品质量。重点讨论了复合超细丙纶及织物的舒适性、染色性和卫生性，应用于织造、服装领域。     

凸轮的表面裂纹分析

本文对一凸轮的表面裂纹进行了分析。渗碳后表层残余奥氏体含量过高级网状碳化物导致该凸轮在精磨过程中出现了磨削裂纹，本文还提出了二次回火或冰冷处理等改进措施来防止磨削裂纹的产生。     

Correction for photon attenuation in SPECT: analytical framework, average attenuation factors, and a new hybrid approach

We provide a unified framework for the investigation of convergence properties of the iterative algorithms for photon attenuation correction in SPECT, including the iterative Chang method--a commonly used approach in which an average attenuation factor calculated over all projection angles is employed in a pointwise correction scheme. A new average attenuation factor calculated along the projection line is introduced, which can compensate exactly for the attenuation effect in the case of a uniform activity distribution. We propose a new hybrid approach in which we use this new average attenuation factor initially and then shift to the iterative Chang method in later iterations. This hybrid approach was evaluated in a simulation study by use of a computer-generated phantom with both non-uniform activity and non-uniform attenuation distributions. The results demonstrate that this hybrid approach improves the convergence speed of the iterative Chang method and produces reconstructed images of high quality.     

Diagnostic significance of CT in the orbital inflammatory lesions

OBJECTIVE: To analyze and summarize the CT signs of orbital inflammatory lesions. METHOD: HITACH-W, or EXEL 2400 pattern of CT was applied for the orbital scanning of 52 cases with orbital inflammatory lesions proved by clinicopathology. RESULTS: The CT signs of orbital inflammatory lesions in our series included exophthalmos, orbital mass, ill-marginated mass, multiple space involvement, extraocular muscle enlargement, scleral thickening, eyelid thickening, optic nerve thickening, orbital fat density increasing, lacrimal gland enlargement, sinusitis, subperiosteal abscess, ring-enhancement in masses, etc. CONCLUSION: All these findings on CT are of important significance for the diagnosis of orbital inflammatory lesions.     

Inoculation mechanism of rare earth–Mg alloy in molten cast iron

The dissolution region of RE–Mg (RE=rare earth) alloy in the reaction chambers of in-mould inoculated castings was studied by scanning electron microscopy and on electron microprobe. The dissolution region of the inoculant was divided into 7 zones according to its microstructure. The RE–Mg alloy is composed of Mg2Si, a Mg2Si–Si eutectic, FeSi, RE–Mg–Si and other silicides. The dissolution of the alloy is a process in which the low melting point phases such as Mg2Si, a Mg2Si–Si eutectic and RE–Mg–Si dissolve first, and the high melting point phases such as FeSi and FeSi2 dissolve later. In addition, some intermediate products form during the dissolution process. This causes a concentration gradient of Mg and RE in the melt which results in a transition of the graphite morphology from normal spheroid to open nodule, vermicular and flake graphite. The dissolution of the FeSi phase in the melt forms local sites of high silicon concentration which promote the nucleation and growth of the graphite. © 1998 Chapman & Hall     

InGaAs（P）分别限制应变单量子阱激光器的优化设计

针对较常用的ＩｎＧａＡｓ（Ｐ）分别限制应变单量子阱激光器，给出了为得到最大净增益的优化设计参数。对于激射波长为１．５５μｍ的无应变激光器，最佳的光限制层波长为１．２４μｍ，厚度为１００ｎｍ。当阱材料引入压缩应变后．由于价带的有效状态密度减小，量子阱激光器的微分增益变大，阱深的增大对增大线性增益的效果更加明显．所以最佳光限制层的波长将变短，为１．２０μｍ     

Variations of physical properties in pellets containing alumina/carbon powder mixtures during reduction and nitridation

Surface area and porosity of pellets containing alumina/carbon powder mixtures during reduction and nitridation were determined. The experimental results indicated that surface area and porosity of solid samples were decreased by increasing the reaction temperature, grain size, forming pressure and the amount of catalyst. Increasing the molar ratio of C/Al₂O₃ and gas flow rate could decrease the surface area and increase the porosity of the solid sample.     

Management of lymphoproliferative disorders after cardiac transplantation

We conducted a retrospective study of 516 cardiac recipients who underwent transplantation between April 1983 and April 1992, 19 of whom had development of post-transplantation lymphoproliferative disorders (PTLDs). These 19 patients presented with involvement of lung (5), gastrointestinal tract (5), disseminated disease (6), and adenoids and lymph nodes (3). B-cell proliferations ranging from an atypical hyperplasia to malignant lymphoma developed in 18 patients, and mixed cellularity Hodgkin's disease developed in 1 patient. The 19 patients with PTLD displayed a predominance of both women and cardiomyopathy as the indication for transplantation when compared with two separate control populations. No correlation was found between demographic criteria analyzed and (1) early versus late diagnosis of PTLD after transplantation, (2) the site of PTLD involvement, or (3) the histopathologic category of the PTLD lesion. Patients with gastrointestinal tract and lung PTLD involvement enjoyed an improved survival after both transplantation and PTLD diagnosis when compared with patients with PTLD involvement of all other extranodal sites. We report a high incidence of PTLD involving the lung and gastrointestinal tract in our cohort study. These sites of involvement responded better to a reduction in immunosuppression than did the other extranodal sites of involvement.