室内良好声环境实现的措施研究

噪声问题是众多城市环境问题中备受关注的问题之一。在人们需要安静休息的住宅、病人需要静养的医院、学生需要静心学习的教室等,都需要良好的声环境。而随着生产的发展和工业体系的完善,噪声污染也越来越严重。本文依据物理原理,对噪声进入室内的方式进行了分类,并对室内噪声声场分布进行分析,从而提出了一些降低室内噪声的可行性措施。     

机载雷达通电的软件模拟设计

以LabWindows/CVI为开发平台,介绍了某型机载雷达通电的软件模拟设计方法。     

Relevance Theory in Translation

In perspective of relevance theory,translation is regarded as communication. According to relevance theory,communication not only requires encoding,transfer and decoding processes,but also involves inference in addition. As communication,translation decision-making is also based on the human beings’ inferential mental faculty. Concentrating on relevance theory,this paper tries to analyze and explain some translation phenomena in two English versions of Cai Gen Tan——My Crude Philosophy of Life.     

Improving the accuracy of GRACE Earth’s gravitational field using the combination of different inclinations

In this paper, the GRACE Earth’s gravitational field complete up to degree and order 120 is recovered based on the combination of different inclinations using the energy conservation principle. The results show that because different inclinations of satellite are sensitive to the geopotential coefficients with different degrees l and orders m, the design of GRACE exploiting 89o inclination can improve effectively the accuracy of geopotential zonal harmonic coefficients. However, it is less sensitive to the geopotential tesseral harmonic coefficients. Accordingly, the second group of GRACE exploiting lower inclination is required to determine high-accurately the geopotential tesseral harmonic coefficients and cover the shortage of the single group of GRACE exploiting 89o inclination. Two groups of GRACE individually exploiting 89o+(82o－84o) inclinations are the optimal combination of the Earth’s gravitational field recovery complete up to degree and order 120. In the degree 120, the joint accuracy of cumulative geoid height based on two groups of GRACE individually exploiting 89o and 83o inclinations is averagely 2 times higher than the accuracy of a group of GRACE exploiting 89o inclination.     

Improving the accuracy of GRACE Earth’s gravitational field using the combination of different inclinations

In this paper, the GRACE Earth＇s gravitational field complete up to degree and order 120 is recovered based on the combination of different inclinations using the energy conservation principle. The results show that because different inclinations of satellite are sensitive to the geopotential coefficients with different degrees l and orders m, the design of GRACE exploiting 89° inclination can effectively improve the accuracy of geopotential zonal harmonic coefficients. However, it is less sensitive to the geopotential tesseral harmonic coef- ficients. Accordingly, the second group of GRACE exploiting lower inclination is required to determine high-accurately the geopotential tesseral harmonic coefficients and cover the shortage of the single group of GRACE exploiting 89° inclination. Two groups of GRACE individually exploiting 89° ＋ （82°-84°） inclinations are the optimal combination of the Earth＇s gravitational field recovery complete up to degree and order 120. In the degree 120, the joint accuracy of cumulative geoid height based on two groups of GRACE individually exoloiting 89° and 83° inclinations is averagely two times higher than the accuracy of a group of GRACE exploiting 89~ inclination.     

A thermally self-sustained micro solid-oxide fuel-cell stack with high power density

High energy efficiency and energy density, together with rapid refuelling capability, render fuel cells highly attractive for portable power generation. Accordingly, polymer-electrolyte direct-methanol fuel cells are of increasing interest as possible alternatives to Li ion batteries. However, such fuel cells face several design challenges and cannot operate with hydrocarbon fuels of higher energy density. Solid-oxide fuel cells (SOFCs) enable direct use of higher hydrocarbons, but have not been seriously considered for portable applications because of thermal management difficulties at small scales, slow start-up and poor thermal cyclability. Here we demonstrate a thermally self-sustaining micro-SOFC stack with high power output and rapid start-up by using single chamber operation on propane fuel. The catalytic oxidation reactions supply sufficient thermal energy to maintain the fuel cells at 500-600 degrees C. A power output of approximately 350 mW (at 1.0 V) was obtained from a device with a total cathode area of only 1.42 cm2.     

同属多项组合项群选手各子项阶段训练安排重要程度的诊断

运用文献资料、访问、问卷调查和数理统计等方法,对同属多项组合项群选手各子项阶段训练安排重要程度的诊断方法进行了初步探讨。给出了不同选手各子项阶段训练安排重要程度的诊断方法与步骤,并对此作了应用举例说明,可为教练员制订训练计划提供参考。     

振动消除大型焊接件残余应力的研究

对焊接试件在时效前后的残佘应力进行了测试比较,阐明焊接件的振动时效和热时效具有相同的作用,均能降低和均化内部残余应力,使工件的尺寸精度获得稳定。通过对大型焊接件的实测,结果表明：采用振动时效处理是可行的,同样可获得降低、均化内部残余应力,稳定几何精度的效果。     

电容传感器灵敏度分布快速计算法及其应用

提出了一种基于有限元的两相流检测用电容传感器灵敏度分布的快速计算法,通过总系数矩阵的快速生成以及快速的电容计算,显著地缩短了灵敏度分布的计算时间,还介绍了该方法在电容层析成象系统及电容式两相流浓度的传感器设计中的应用。     

混凝土材料声发射过程及其自相似性的研究

将对材料声发射的研究同对力学过程的研究、材料断裂损伤等破坏过程的研究相结合,提出了声发射过程的概念。在此基础上,进一步给出了定量考察声发射过程自相似性的自相似特征函数。测试结果分析表明,混凝土试块在单轴压缩过程中,声发射过程的自相似程度随着应力状态的变化而变化。