宽带抽运情况下乙醇、丙酮溶液中受激拉曼散射光谱的实验研究

研究了乙醇、丙酮两种拉曼介质在宽带抽运情况下啁啾激光脉冲的受激拉曼散射频谱特性 ,得到的一级Stokes光频谱宽度与抽运光基本相当 ,且具有较高的转换效率 ,从而表明了利用“展宽—受激拉曼散射—压缩”的办法获得波长近 1μm的飞秒级超短脉冲激光信号源的实验方案具有可行性     

A Novel UWB Pulse Shape Modulation System

In this paper novel modified Hermite polynomial functions for use in impulse radio (ultra-wideband) communications are proposed. With these functions pulse shapes which are orthogonal and have nearly constant pulse width regardless of the pulse order are generated. These properties hold under the effects of differentiation. An M-ary communication system is constructed using these pulse shapes. A Matlab model for generating the pulses is designed and the effect of timing jitter on the performance of the system is investigated by computer simulation.     

一种简易可靠的射频激光调制器

采用ＰＩＮ电调衰减器、ＴＬ４９４等元件组成了射频（ＲＦ）大功率ＣＯ２激光调制器，调制频率、占空比和调制度单独可调。给出了电路的工作原理和测试结果。     

液氮温区同轴脉冲管制冷机的实验研究

脉冲管制冷机冷头朝上布置可以使制冷机与超导器件的耦合更方便 ,但对G -M型脉冲管制冷机 ,重力会对这种布置方式产生不利影响。对双向进气型脉冲管制冷机 ,直流和耦合传热会共同影响脉冲管制冷机的性能。介绍了液氮温区G -M型同轴脉冲管制冷机的实验结果 ,主要研究了蓄冷器温度分布和重力对脉冲管制冷机性能的影响     

Change of characteristics of desulfurization and denitrification by combustion flue gas composition and electrode configuration under pulsed corona discharge

Laboratory-scale and parametric experiments of SO₂ and NO_x removal from the simulated combustion gas by pulsed corona discharge have been performed by changing the combustion gas composition and temperature, the electrode configuration of plasma reactor, and the polarity of high-voltage electrode. The following results are obtained: 1) the higher the concentration of H₂O and O₂, the higher the efficiency of desulfurization and denitrification at the same specific input; 2) the pulsed corona discharge with a voltage pulsewidth as short as 200 ns of negative polarity shows the possibility to attain almost 90 percent deSO_x and deNO_x efficiency at the specific discharge input of 20 J/g, which is almost the same as the specific input in the electron-beam process; 3) the deNO_x characteristics show a little temperature dependence in the range of 70 to 130°C, but the deSO_x efficiency increases rapidly in the temperature region below 100°C suggesting the thermochemical dependence of deSO_x reaction; 4) when desulfurization and denitrification proceed, the white dendritic powder deposits on the plasma reactor whose composition is identified to be 49 mol% (NH₄)₂SO₄ and 47 mol% of 2NH₄NO₃ · (NH₄)₂SO₄, and the ratio of SO₂, NO and NH₃ of the deposit is almost equal to that of supplied gas.     

ECAP细化晶粒法的仿真与分析

ECAP(Equal Channel Angular Extrusion)方法，是实现材料纯剪切变形的有效方法。本文采用有限元（FEA）分析软件ANSYS对Al的挤压过程进行仿真与分析。分析结果表明：外切角Φ、圆角半径、试样与凹模之间的摩擦系数、凹模本身的特性（如弹性模量、泊松比等）等等，对材料的变形量都有不同程度的影响。     

高非线性光纤及其应用

介绍了各种高非线性光纤的原理，并对其在超连续（SC）脉冲的产生和波长变换上的应用作了讨论。     

水力脉冲式钻井工具的研制与应用

水力脉冲式钻井是利用特定的工具使钻井管柱中的连续流转变为脉冲射流,从而改变井底流场的压力状况,进而提高机械钻速的一种钻井新工艺。在分析水力脉冲产生机理的基础上,探讨了基于瞬变流理论的机械阻断式水力脉冲破岩机理,介绍了SLPMC机械阻断式水力脉冲工具的工作原理及结构特点,简单叙述了该工具在胜利油田进行的2口井的现场试验情况。该钻井工具对于提高机械钻速和降低钻井成本具有一定的积极意义。     

Service Load Effective Compression Flange Width in Fiber Reinforced Polymer Deck Systems Acting Compositely with Steel Stringers

This paper reports on the field study of a steel stringer-fiber reinforced polymer (FRP) deck composite bridge in Pennsylvania. The objective of the study is to assess the effective compression flange width in the FRP deck and floor systems when they act compositely with underlying steel girders at service conditions. The research results reported herein support the notion of employing a design approach, for both interior and exterior girders of a composite floor system, that is philosophically consistent with current practice related to steel girders acting compositely with concrete decking. It appears from the results presented herein that FRP decks and floors acting compositely with underlying steel girders exhibit an effective width that is close to the actual girder spacing for interior beams, and approximately one-half this value for exterior beams.     

脉冲电镀的正向电流密度对深镀能力的影响

主要通过在正反向电流比、频率、脉冲宽度一定的条件下,改变正向电流密度的大小来研究其对PCB整板电镀铜深镀能力的影响。从测得的数据可知随着正向电流密度的增大,深镀能力先变大后变小,并对这个问题进行了理论分析。