立式聚合釜气液传质特性的研究

本文旨在开发新一代聚四氟乙烯立式反应釜。分别在纯水-氧、乳化剂水溶液-氧两个体系中,用纯氧物理吸收法测定了H/D=1.27的釜的传质容量系数K_La,分析了两体系K_La差别的原因,并对实验结果进行了关联。研究表明,水体系的K_La,是乳液体系的2.5倍,桨型、安装位置等参数对传质有明显影响。在H/D≤1.27的釜中以单层三叶船舶推进器为最佳桨型。     

Glass–Crystal Transition in II-IV-V2 Semiconducting Compounds

The crystallization behavior of amorphous CdGe_xAs₂, where the x values were varied from 0 to 1.2, was studied in order to document the effect of germanium on the amorphous structure. The glass-forming tendency of amorphous CdGe_xAs₂ was evaluated by Hruby's criterion. The crystallization mechanism of each group was proposed, interpreting DSC, XRD, EDS, and TEM data, interactively. The crystallization behavior appeared as two distinct groups: those based on the CdAs₂ structure and those on the CdGeAs₂ structure (chalcopyrite), depending on Ge content. Ge atoms were found to suppress a glass-to-glass exothermic transformation to higher temperatures in the CdAs₂ group, and crystallization in both groups. Proposed models of amorphous structure from previous investigators, measuring the radial distribution function, magnetic susceptibility, and macroscopic density, were correlated to the crystallization studies herein. A model of the transformation of glass structure with increasing Ge content from a CdAs₂ to a CdGeAs₂-like structure was established by extrapolation of experimental results indicating this behavior in crystalline CdGe_xAs₂ compounds with varying x .     

3-D structure-property relationships in rolltruded polymers. Part II: Anisotropic yielding and deformation in triaxially oriented polymers

Rolltrusion, a single step solid state deformation process, has been successfully applied to isotactic poly(propylene), iPP, to produce unique 3-D properties. Mechanical property enhancement not only occurs in the principal draw direction, but also in the transverse directions. A systematic series of standard (ASTM) tensile and compressive experiments were made on well oriented materials supporting this claim. Tensile testing was also performed on dumb-bell shaped specimens cut at various angles to the main deformation direction. A variety of observations were made during testing. Deformation bands, anisotropic yielding, and ductile-to-brittle behavior were observed. These results are presented along with a morphological model that has been developed to account for the behavior of these unique triaxially oriented polymers.     

南京互动电视平台的建设与运营

本文介绍了南京广电网络互动电视平台的总体戎麒南京广电网络有限责任公司数字电视中心副经理发展战略、设计建设特点和业务运营思路,详细阐述了互动电视技术系统建设中的关键技术选择、技术创新点和业务宣传营销实践中的理念和策略.     

基于PSCAD的蓄电池模型的仿真研究

蓄电池仍是目前各领域重要且基本的储能元件,有必要继续深入和优化研究蓄电池的仿真模型以及动态特性等.该文先概述了蓄电池的典型参量,随后对比分析了多种电池等效电路模型,最终采用三阶动态模型在PSCAD软件中建立了常规2V铅酸蓄电池的仿真模型,并用仿真验证了等效模型的有效正确.对储能系统在徽电网中的运用奠定了理论和仿真基础.     

某雷达三通道高频接收机的设计与实现

论述某雷达独立三通道高频接收机的工作原理及其工程实现,对其中的关键技术提出了解决方法,并给出了设计及试验的结果。     

A novel interference suppression scheme for global navigation satellite systems using antenna array

This paper considers interference suppression and multipath mitigation in Global Navigation Satellite Systems (GNSSs). In particular, a self-coherence anti-jamming scheme is introduced which relies on the unique structure of the coarse/acquisition (C/A) code of the satellite signals. Because of the repetition of the C/A-code within each navigation symbol, the satellite signals exhibit strong self-coherence between chip-rate samples separated by integer multiples of the spreading gain. The proposed scheme utilizes this inherent self-coherence property to excise interferers that have different temporal structures from that of the satellite signals. Using a multiantenna navigation receiver, the proposed approach obtains the optimal set of beamforming coefficients by maximizing the cross correlation between the output signal and a reference signal, which is generated from the received data. It is demonstrated that the proposed scheme can provide high gains toward all satellites in the field of view, while suppressing strong interferers. By imposing constraints on the beamformer, the proposed method is also capable of mitigating multipath that enters the receiver from or near the horizon. No knowledge of either the transmitted navigation symbols or the satellite positions is required.     

折射/衍射混合长波红外连续变焦光学系统设计

为了提高图像的分辨率,提高红外系统的探测距离和探测精度,满足多种条件下的使用要求,基于最新的非制冷型384288凝视型焦平面阵列探测器,设计了折射/衍射混合长波红外连续变焦光学系统。系统工作波长为8～12 m,F数1.5,变倍比25:1。设计过程中,系统引入衍射面构成折/衍射混合结构,校正色差和高级像差,减少了透镜的使用数量,简化了系统结构。最后利用CODE V 光学设计软件进行了优化设计和像质评价,设计结果表明,系统在探测器的Nyquist频率（20 lp/mm）处,所有变焦距位置和视场的MTF值均大于0.4,接近系统的衍射极限。系统具有变倍比大、分辨率高、像质好、结构简单等特点,可应用于众多光电探测领域。     

CPM中相关同步技术的研究

针对连续相位调制系统,提出了一种利用相关器来辅助实现同步的方法,分为差分相关、绝对相位相关两种方法.通过MATLAB仿真,分析了两种相关方法的性能.在性能最佳的基础上,提出了一种利用FPGA实现的简化算法,节省了FPGA芯片的逻辑资源,使相关器的FPGA有效实现变为可能.