Bistatic radar scattering by a chaff cloud

The bistatic radar scattering cross section of a chaff cloud is investigated in the ground-based system for arbitrarily polarized transmitters and receivers. The chaff cloud considered consists of a large number of identical thin conducting wires whose thickness is very small compared to their length and to the wavelength. Numerical results for bistatic cross sections for the cases of orientations uniform in azimuth and Gaussian in elevation, and also for uniformly random orientation in both azimuth and in elevation are presented in the form of three-dimensional graphs, for a few typical examples     

铟镓砷磷半导体激光的生物特性及73例椎基底动脉供血不足者的治疗

通过对甸镓砷磷半导体激光和常用He-Ne激光生物特性进行初步比较,说明半导体激光对治疗椎基底动脉供血不足疗效较明显。     

2‐Cyanoprop‐2‐yl dithiobenzoate mediated reversible addition–fragmentation chain transfer polymerization of acrylonitrile targeting a polymer with a higher molecular weight

The reversible addition–fragmentation chain transfer (RAFT) polymerization of acrylonitrile (AN) mediated by 2‐cyanoprop‐2‐yl dithiobenzoate was first applied to synthesize polyacrylonitrile (PAN) with a high molecular weight up to 32,800 and a polydispersity index as low as 1.29. The key to success was ascribed to the optimization of the experimental conditions to increase the fragmentation reaction efficiency of the intermediate radical. In accordance with the atom transfer radical polymerization of AN, ethylene carbonate was also a better solvent candidate for providing higher controlled/living RAFT polymerization behaviors than dimethylformamide and dimethyl sulfoxide. The various experimental parameters, including the temperature, the molar ratio of dithiobenzoate to the initiator, the molar ratio of the monomer to dithiobenzoate, the monomer concentration, and the addition of the comonomer, were varied to improve the control of the molecular weight and polydispersity index. The molecular weights of PANs were validated by gel permeation chromatography along with a universal calibration procedure and intrinsic viscosity measurements. ¹H NMR analysis confirmed the high chain‐end functionality of the resultant polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1272–1281, 2007     

Kinetic behaviour of aluminum naphthenate/benzene system in process of gelation and degradation

The kinetic behaviour of aluminum naphthenate/benzene system in the process of gelation and degradation was systematically studied. The results obtained from the kinetic experiments indicated that the gelation stage was in accordance with a kinetic model of an auto-catalytic first-order reaction, and the degradation stage was a simple first-order reaction. The rate constants in these two stages at various temperaturs were measured. And the determined apparent activation energies for the gelation stage and for the degradation stage are 27.5±2.0 and 37.7±2.3 kJ/mol, respectively.     

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     

建立军用Foundry的探索

本文从ASIC的基本特点出发,阐述了建立ASIC标准加工线(Foundry)的重要性;国内集成电路产业已经具备建立Foundry的基础,建立有中国特色的Foundry是可以有所作为的。文章介绍了作者在建立军用Foundry方面的探索和初步成果。     

X射线聚束透镜原理及其应用

本文阐述了一种新型的Ｘ射线聚束装置─—Ｘ射线透镜的聚束原理。给出了透镜的基本设计方法，并对它应用于Ｘ射线光刻研究领域的前景作了展望。     

利用表面等离子体波共振效应(SPRE)对角度与共振波长关系的研究

本文利用了Kretchmann模型的表面等离子体波共振效应，研究了共振波长对入射角变化的敏感性，从而为研制一种新的角度传感器提供了依据。     

A spectrally efficient constant envelope modulation technique forPCS and mobile communications

A newly developed constant envelope FQPSK modem/radio architecture, which employs a modified double-jump (DJ) filter in the cross-correlated FQPSK system, is proposed for personal communications systems (PCS) and mobile radio applications. Power efficiency, spectrum efficiency, BER, and system capacity of this system are investigated in a non-linear amplified (NLA) Rayleigh fading environment. We demonstrate that with the simplest threshold detectors (binary robust eye diagrams in I and Q channels), this system is 4-7 dB more power efficient than the US digital cellular and Japanese Handyphone standard π/4-QPSK, 50%-100% more spectrally efficient than the European standard GMSK, and it almost double the capacity of GMSK     

YAG脉冲激光器快速连通保护系统

本文阐述了ＹＡＧ脉冲激光器的一种快速连通保护系统，利用大功率二极管作为连通故障信号检出的关键元件，采用了可控硅与继电器双重保护，使得整个保护系统既快速可靠，又简便适用。