CDMA时变色散信道的两级盲辨识算法

本文通过对时变信道的扩展函数在时频域进行正则采样，得到了CDMA时变系统的离散正则模型。针对该模型提出了一种具有较低运算量的两级盲辨识算法。为避免两级算法产生的误差传播效应，文章将理想SIMO模型等效为加性噪声模型来处理。与基展开模型方法相比，该算法具有不需利用观测数据的高阶统计量估计展开基频率的优点。文章通过仿真验证了该算法是可行的。     

地源热泵的地热能利用方式与工程运用

地源热泵是一种新型的高效、节能、环保的空调系统 ,是我国调整能源利用结构 ,发展利用可再生能源策略的重点推广项目之一。本文介绍了地源热泵的工作原理及四种地热能利用方式。根据笔者的设计经验 ,为地源热泵空调系统的工程设计和推广应用提供了一些设计参数和参考意见     

合成孔径雷达图像的恒虚警率目标检测

目的　对合成孔径雷达 (SAR)图像实施恒虚警率 (CFAR)目标检测 .方法　利用 K-Gamma和Weibull分布的杂波模型分别对海面和陆地的人造目标实施检测 ;同时 ,对不同杂波背景下 CFAR检测方法进行比较 .结果与结论　通过检测结果的比较 ,证实了 K-Gamma分布和 Weibull分布分别适合于海面和陆地杂波背景下的目标检测 ;在非均匀杂波背景中 ,有序统计量 (OS)较单元平均 (CA)方法具有优越性     

对投入与产出优化分析方法的应用探讨

介绍投入与产出优化分析的一些基本概念和计算方法 ,并结合实际 ,举例说明投入与产出的优化分析方法具体应用     

偏振模色散统计特性的研究

利用动态方程研究了偏振模色散矢量的统计特性 ,分别用统计系综和频率系综两种方法进行数值模拟。数值结果表明 ,统计系综和频率系综两种方法的结果一致。在大归一化距离条件下 ,均方根时延的平方随归一化距离线性变化 ;偏振模色散矢量的各个分量服从高斯分布 ,差分群时延服从麦克斯韦分布 ;偏振模色散矢量弥散于整个邦加球     

Pad effects on material-removal rate in chemical-mechanical planarization

The role of a porous pad in controlling material-removal rate (MRR) during the chemical-mechanical planarization (CMP) process has been studied numerically. The numerical results are used to develop a phenomenological model that correlates the forces on each individual abrasive particle to the applied nominal pressure. The model provides a physical explanation for the experimentally observed domains of pressure-dependent MRR, where the pad deformation controls the load sharing between active-abrasive particles and direct pad-wafer contact. The predicted correlations between MRR and slurry characteristics, i.e., particle size and concentration, are in agreement with experimentally measured trends reported by Ouma¹ and Izumitani.²     

浅析橡胶硫化模具的化学清洗

模具清洗是一般橡胶制品生产过程中不可缺少的环节，本文仅对模具化学清洗方法作一浅析，供大家探索和研究，以便更加有效地清洗模具，提高成品质量以及生产效率。     

多工况多级离心压缩机总体优化命题的建模与数值方法

介绍了多工况 点的压缩机最优模拟设计点的特点及相应的优化建模，包括目标函数的建立、约束条件的确立和计算方法，使满足该模拟设计点要求的压缩机在逼近优目标函数最大值的同时，兼顾各真实工况运行点都在较好效率下工作，并列出了基于模型级数据库的优化设计实例。     

铜萃取剂BK992和LIX984的性能研究

研究羟肟类铜萃取剂的结构与性能的关系。试验研究了铜萃取剂BK992和LIX984的对比萃取及混合萃取性能指标 ,试验表明BK992与LIX984的使用性能相当 ,两种铜萃取剂相互混合不影响使用性能指标。     

Nonepitaxial Orientation in Sol–Gel Bismuth Titanate Films

Control over crystallographic orientation in ceramic thin films is important for highly anisotropic structures. Layered perovskites, like Bi₄Ti₃O₁₂, have interesting properties associated with their ferroelectric nature, which may be fully exploited only when films are highly textured. Textured films of this titanate were fabricated via a sol–gel technique without using epitaxial growth. Orientation in the film is confirmed by XRD and SEM, and supported by refractive index and dielectric measurements. In an attempt to explain the orienting effect, light scattering experiments were conducted to yield information about the molecular size, shape, and conformation of macromolecules as the sol–gel solution ages and condensation reactions proceed. These experiments clearly show an increase in the size of molecular clusters with time. We believe that it is the organization of these large clusters during spin coating, and the relationship of the backbone chemistry to the crystal structure of Bi₄Ti₃O₁₂, that are responsible for the observed orientation.