A near-optimal multiuser detector for DS-CDMA systems using semidefinite programming relaxation

A multiuser detector for direct-sequence code-division multiple-access systems based on semidefinite programming (SDP) is proposed. It is shown that maximum likelihood (ML) detection can be carried out by "relaxing" the associated integer programming problem to a dual SDP problem, which leads to a detector of polynomial complexity. Computer simulations that demonstrate that the proposed detector offers near-optimal performance with considerably reduced computational complexity compared with that of existing primal-SDP-relaxation based detectors are presented.     

工业层析洗梯液回收套用的一种方法

以生产甲胺基阿维菌素苯甲酸盐精品的工艺——工业层析产生的洗梯液回收套用的过程为例，说明利用二元恒沸物的组成随压力的变化而变化的规律，对生产洗梯液进行有效、简洁、合理分离及套用的方法。     

用热失重法确定水合粘土水分含量及存在形式

文章以蒙脱土为例，采用热失重法定性定量确定了水合粘土中结合水类型、界限及其相对含量，并与等温吸附法结果进行了对比。结果表明，用该方法得到的水合蒙脱土中各种水分的相对含量及总含水量与等温吸附实验结果相一致。热失重（25~250 ℃）分析结果表明，水合蒙脱土中水分子主要存在自由水、松散吸附结合水、紧密吸附水（强吸附结合水）3种状态，分别对应于25~75 ℃、75~120 ℃、120~230 ℃区间里的失水。从热失重（25~250 ℃）规律来看，仍存在两个明显的转折点p/ps=0.9、0.98，它们为粘土-水体系的两个特征湿度，前者为粘土表面强结合水与松散结合水（渗透结合水）之间的界限，后者为松散结合水与自由水之间的界限，这验证了等温吸附法确定的两个特征湿度及对粘土表面结合水界限划分的正确性。     

Effects of Background Plasma on Free Electron Laser with Planar Wiggler

Dispersion equation of planar-wiggler free-electron laser with background plasma is derived using linear fluid theory. The characteristic of this plasma FEL is analyzed in detail. It is shown that reasonable background plasma density tends to improve FEL growth rate. We also find there exits a critical plasma density for FEL operating. When the background plasma density is higher than critical density, the FEL can no longer be excited.     

Gamma-Ray-Induced Multi-Effect on Properties of Chalcogenide Glasses

Gamma-ray irradiations induced various alterations in sulfur- and selenium-based chalcogenide glasses. The absorbed dose was in the range of 0.01–3.6 MGy. The glasses exhibit prominent sensitivity to γ-ray irradiation, characterized by changes in some of the physical properties of the glasses, e.g., optical transmission, optical band gap, density, and thermal expansion coefficient. The effects on glass structure and microscopic morphology were also studied by Raman spectra and scanning electron microscopic observations.     

曹向联 永不枯竭的动力

人们都叫他引领企业攀升的曳引机，老职工们亲切地称呼他为“老大”，但我们见到的他却既不“高”也不“大”，甚至身板略显文弱，带着厚厚的眼镜，乍一见，你一定以为他是大学里的教授。就是这样的一个人，却成为这个有着数百名职工的企业的心脏，永不停歇地为企业输送着血液和动力。     

鞍钢2130 mm双剪刃飞剪装配

论述双剪刃飞剪装配方案的制订及精度调整方法。     

邢台矿区下组煤带压开采水害防治技术的探讨

阐述了邢台矿区的水文地质特征，影响下组煤开采的主要充水因素，重点总结了公司下组煤带压开采的实践经验、技术路线和关键的防治水技术。