高纯锗探测器的快定时性能及其应用

为了将高纯锗（ＨＰＧｅ）探测器用于快定时的物理实验中，本实验研究厂影响高纯锗探测器定时谱仪时间性能的各种因素，找出了获得谱仪最小时间分辨的各种最佳参数。并建立了分辨时间为４．１９ｎｓ，能量分辨率为２０ｋｅＶ，微分非线性好于±２．０％，计效率可承受１２０×１０￣３ｓ￣（－１）的时间微分扰动角关联谱仪。利用此谱仪，以￣（２０４）Ｂｉ为探针核，研究了Ｂｉ系高温超导的微观机理，取得了较好的结果。     

Application of asymptotic waveform evaluation to eigenmode expansion method for analysis of simultaneous switching noise in printed circuit boards (PCBs)

In this paper, the asymptotic waveform evaluation (AWE) technique is first applied to the conventional eigenmode expansion method for characterizing a power/ground (P/G) plane pair and analyzing the simultaneous switching noise on such plane pairs for printed circuit boards or multichip modules. The application of AWE avoids a large number of iterations in computing the impedance frequency response of a P/G plane pair structure and greatly reduces the computation time. Meanwhile, to obtain an accurate solution in an entire frequency range, we employ the complex frequency hopping technique which can help select multiple expansion points. In addition, the proposed approach can also be used to characterize the P/G plane pair structures with irregular shapes. Three examples demonstrate its high efficiency and good accuracy.     

陇上天路

如果说青藏铁路是一条“雪域天路”，那么宝鸡至天水高速公路就是一条“陇上天路”。宝鸡至天水是从关中平原到西北黄土高原的跨越地段，垂直跨度大，山连山，岭连岭，几乎看不到任何平原地段。作为2005年西部新开工的十大工程和交通部十二项示范工程之一，这条全长91公里的高速公路还要穿过甘肃屈指可数的林带，跨越黄河、长江两大流域，穿越甘肃最大的天然林保护基地--小陇山林业自然保护区、麦草沟自然保护区和麦积山国家森林公园。     

Discrete Modeling and Suggested Measurement of Heat Transfer in Gas-Solids Flows

This article presents a two-dimensional transient model for gas-solids flow and heat transfer through pipes using the coupled Computational Fluid Dynamics and Discrete Element Method approach. Numerical simulations have been conducted to examine the modification of fluid thermal structure due to the presence of particles in a pneumatic transport pipeline. Modeled results have demonstrated the key role of transversal motion of rebounding particles in the pipe cross section in altering fluid temperature. Further implementation of this modeling technique in air-drying processes is discussed and possible experimental methods for the measurement of in situ particle and fluid motion and temperature profile are cited.     

科尔沁区清河镇HFC网络设计方案

介绍通辽市科尔沁区清河镇有线电视发展的现状,提出清河镇有线电视网络的规划设计方案,对网络指标进行具体验算,并简要分析网络建设中光缆路由的敷设方式。     

A polymerizable photoredox initiation system for vinyl photopolymerization

A polymerizable photoredox system consisting of 4-methacryl oxbenzophenone (MABP) and N,N-dimethlaminoethyl methacrylate (DMAEMA) used for the photopolymerization of acrylonitrile (AN) was studied. It was found that the polymerization rate is proportional to the 0.93th power for the AN concentration, the 0.28th power for the MABP concentration, and the 0.25th power for the DMAEMA concentration. The overall activation energy of the polymerization obtained is 30.43 kJ/mol. The recorded ESR spectrum indicates that the excited-state MABP abstraets hydrogen mainly from the methyl group of the dimethylamino moiety. The comparison of the initiation ability of polymeric MABP or polymeric DMAEMA with their monomeric forms has also been done and the results indicate that in good solvents P (MABP) has a much higher initiation ability than that of monomeric MABP, but monomeric DMAEMA and P (DMAEMA) display almost the same initiation ability. In poor solvent, the initiation ability of P (MABP) is not so obviously higher than that in good solvents. The result of UV analysis of P (AN) initiated by the MABP–DMAEMA system indicates that both MABP and DMAEMA not only initiate the photopolymerization of AN, but also enter into P (AN) polymer chains. © 1994 John Wiley & Sons, Inc.     

STRUCTURE REPRESENTATION OF THE SPECIFIC FRACTIONS FROM PINGSHUO COAL

Basic data of four fractions, PM₁, PM₆, PM₇and PM₈, derived from Pingshuo bituminous coal were obtained by ultimate analyses, mean molecular weight measure, GC/MS, ¹³C-NM R, ¹H-NM R and FTIR technigues. A method of calculating the average molecular parameters of the fractions is introduced. Based on the calculated parameters, the molecular structure models of the fractions of PM₆, PM;and PM₈are constructed. Significant structural information about the saturated hydrocarbon and aromatic hydrocarbon with heteroatom groups is given also.