有线电视技术档案管理初探

针对有线电视技术档案管理的现状及存在的问题，提出了解决问题的措施。     

A compact LTCC branch-line coupler UsingModified-T equivalent-circuit modelfor transmission line

In this letter, a compact branch-line coupler is proposed by making good use of the three-dimensional layout capability of the low-temperature co-fired ceramic (LTCC) substrate. This branch-line coupler is accomplished by using lumped-inductors and lumped-capacitors to realize the modified-T equivalent-circuit model for the transmission line so that the circuit size may drastically be reduced. Specifically, a very compact LTCC branch-line coupler with a size of 0.079/spl lambda//spl times/0.0717/spl lambda/ is implemented and carefully examined, where /spl lambda/ is the wavelength of the multilayer structure at the operating frequency f/sub 0/.     

Robust Space Time Receiver for CDMA-based Antenna Arrays

In this paper, we propose a new robust code division multiple access (CDMA) receiver of which weight vector is obtained by projecting the effective spatio-temporal signature waveform onto the signal subspace of the data covariance matrix. We verified our proposed algorithm by the field measured data obtained with a custom-built wideband CDMA test-bed. It will be shown that the proposed algorithm is robust to the signal mismatch.     

PbZr0.52Ti0.48O3薄膜红外椭圆偏振光谱研究

用磁控溅射法在Pt/Ti/SiO2 /Si衬底上制备了PbZr0 .52 Ti0 .4 8O3(PZT)薄膜 .XRD结果表明经过退火后的PZT薄膜呈现多晶结构 .通过红外椭圆偏振光谱仪测量了λ为 2 .5～ 12 .6 μm范围内PZT薄膜的椭偏光谱 ,采用经典色散模型拟合获得PZT薄膜的红外光学常数 ,同时拟合得到未经处理的PZT薄膜和退火后PZT薄膜的厚度分别为 45 4.2nm和 45 0 .3nm .最后通过拟合计算得到结晶PZT薄膜的静态电荷值为 |q|=1.76 9± 0 .0 2 4.这说明在磁控溅射法制备的PZT薄膜中 ,电荷的转移是不完全的 .     

Effect of Substrate Bias on Microstructure and Properties of Tetrahedral Amorphous Carbon Films

The microstructure and properties of tetrahedral amorphous carbon (ta-C) films deposited by the filtered cathodic vacuum arc technology has been investigated by visible Raman spectroscopy, AFM and Nano-indentor. The Raman spectra have been fitted with a s     

降低精炼钢中氢氧含量的探索

主要介绍通过优化炼钢生产工艺,使产品满足新的技术要求:S≤0.010％,P≤0.015％.[H]≤0.0002％,[O]≤0.0045％,[N]≤0.0055％。     

鱼雷罐喷粉预处理过程水模研究

在鱼罐喷粉预处理水模实验数据的基础上，进一步利用线性回归确定各工艺操作参数对喷吹基本参数（均混时间、粉剂穿透比和粉剂停留时间）的影响，得出各传输动力学基本参数的函数关系式。     

稀土Pr对Al2O3-SiO2(Sf)/ZL109复合材料组织及性能的影响

本文采用挤压浸渗法 ,制得不同稀土含量的硅酸铝短纤维增强铝基复合材料。用光学显微镜观察了复合材料的铸造显微组织 ,分析了稀土含量对共晶硅组织形态的影响 ;用扫描电镜对复合材料基体中的稀土相进行了观察 ,探索了稀土相的分布位置及其形态 ;并对不同稀土含量的复合材料进行了摩擦磨损实验 ,结果表明稀土能增强复合材料的耐磨性     

ARTIFICIAL INTELLIGENCE CONTROL OF FOOD FREEZER USING ROTATING DISK AIR DISTRIBUTOR FOR UNIFORM FREEZING

A rotating disk air distribution (RDAD) system consisting of a rotating disk with an air supply hole was fabricated to solve the nonuniform freezing problem of a freezer that supplies air through a duct at a fixed location. The RDAD system was installed in a freezer to supply freezing air in various directions by controlling the position of the air supply hole. An equation estimating air velocity in the freezer was developed based on heat balance between a brass block thermocouple (BBT) probe and ambient air stream. The equation was applied to the analysis of airflow patterns developed through the RDAD and the fixed duct system. For control of the RDAD system, a fuzzy matrix was constructed with the measured nodal temperature at 3D locations in the freezer and used to search for the optimum direction of air supply. Uniform cooling was accomplished with the RDAD system using fuzzy and expert algorithms leading to temperature deviation σ=0.666, compared with 0.289 of the fixed air supply system. Cooling rate of model food (BBT) was 1.75 times faster than that of the fixed system.     

Synthesis and characterization of poly(siloxane-urethane)s

A series of polyurethane block copolymers based on hydroxy-terminated polydimethylsiloxane and poly(propylene glycol) soft segments of molecular weights 1818 and 2000, respectively, were synthesized. The hard segments consisted of 4,4′-diphenylnethane diisocyanate and 1,4-butanediol as the chain extender. Samples with different molar ratios were prepared. We tried to synthesize polydimethylsiloxane-based polyurethanes (PDMS-PU) containing a hard block as major fraction and a soft block as minor fraction for preparing toughened rigid systems. After a study of the pure polydimethylsiloxane-based polyurethane and poly(propylene glycol)-based polyurethane (PPG-PU), (mixed polyol)-based block copolymers and blends of PDMS-PU and PPG-PU were synthesized, and characterized by means of differential scanning calorimetry, tensile testing and scanning electron microscopy. In (mixed polyol)-based copolymers and lower hard-segment content blends, macro-phase separation occurred, but blends with higher hard-segment contents showed significant reduction in amounts of phase separation.