脉冲爆震燃烧室出口燃气能量分布特性

为了提高脉冲爆震燃烧室出口燃气能量转换效率,采用数值计算方法,研究了带气动阀和爆震增强结构的脉冲爆震燃烧室出口燃气能量分布特性,结果表明:脉冲爆震燃气的膨胀过程先后经历一次膨胀、二次膨胀和过度膨胀3个阶段,单个周期内二次膨胀阶段的时间和能量占比最大;燃烧室出口燃气压力势能、动能、内能和能流密度的分布主要受燃气压力的影响,且变化规律与燃气压力一致;一次膨胀阶段燃气增加的压力势能、动能、内能分别占单个周期的479%、259%、251%;二次膨胀阶段燃气增加的压力势能、动能、内能分别占单个周期的502%、576%、581%。     

脚尖数据的研究及其分析

大部分步态研究者将注意力投入到臀部和膝盖关节的角度变化所形成的步态特征,脚的步态特征关注还较少。针对这个问题深入研究了脚的一些特征,提取了脚尖数据进行分析,并对脚尖的坐标进行变换得到时域、频域及其他信息,在中科院数据库NLPR上进行试验和研究,表明脚尖的数据可以较好的区分男女性,甚至是不同的个体。脚尖数据的表示包含了较多的属性信息,有利于步态识别的进一步研究。     

地源热泵技术在建筑节能中的应用

本文探讨如何通过地源热泵技术实现建筑节能。研究通过地源热泵来实现一机多用,使其既能用于冬季供暖,又可以用于夏季制冷。同时也讨论了如何与太阳能相配合,来实现地热平衡。文中还给出了通过插值法和曲线拟合法对测量数据进行处理获得变温带和增温带的温度-深度曲线的方法。     

On the origin of ultrahigh energy cosmic rays

The origin of cosmic rays with energy E ? 10¹⁸ eV is a long-standing problem in astrophysics. The development of ever larger detectors has brought in key experimental results in the past decade, most particularly the detection of a cut-off at the expected position for the long sought Greisen–Zatsepin–Kuzmin suppression as well as evidence for large scale anisotropies. This paper summarizes and discusses the recent achievements in this field.     

国际空间太阳能电站的技术进展

综述了当前国际空间太阳能电站技术的研究进展与发展趋势。重点介绍了空间太阳能电站系统方案新构思“太阳塔”和“太阳盘”的特点；介绍了空间太阳能电站的主要相关技术———无线电能传输技术、太阳能转换技术和空间运输技术等的发展趋势；最后简要介绍了月球电站的进展情况。     

Grinding performance evaluation of porous composite-bonded CBN wheels for Inconel 718

For high-efficiency grinding of difficult-to-cut materials such as titanium and nickel alloys, a high porosity is expected and also a sufficient mechanical strength to satisfy the function.However, the porosity increase is a disadvantage to the mechanical strength. As a promising pore forming agent, alumina bubbles are firstly induced into the abrasive layer to fabricate porous cubic boron nitride（CBN） wheels. When the wheel porosity reaches 45%, the bending strength is still high up to 50 MPa with modified orderly pore distribution. A porous CBN wheel was fabricated with a total porosity around 30%. The grinding performance of the porous composite-bonded CBN wheel was evaluated in terms of specific force, specific grinding energy, and grinding temperature, which were better than those of the vitrified one under the same grinding conditions. Compared to the vitrified CBN wheel, clear straight cutting grooves and less chip adhesion are observed on the ground surface and there is also no extensive loading on the wheel surface after grinding.     

Stability analysis of an aeroelastic system with friction

In this paper, harmonic balance method, exact formulation and numerical simulation method are adopted to study the effects of different friction stiffness on the stability of 1.5 degrees of freedom aeroelastic system. On this basis, the expressions of input energy and dissipated energy are deduced, and the energy method is used to reveal the mechanisms of the stable boundary and unstable boundary existing in the system and the effects of different friction stiffness on the stability of the system. Studies have shown that the stability region and the critical aerodynamic damping ratio of the system rise with the increase of the friction stiffness, while the friction stiffness has little effect on the stability boundary. In the analysis of the stability of system, the results of harmonic balance method, exact formulation and Newmark of numerical simulation method are in good agreement. Compared with exact formulation and numerical simulation method, the concept and conclusion of harmonic balance method are simple in the system stability analysis.     

一种实现陀螺马达准确制动方案的研究

在分析了几种传统的电机制动方案基础上,提出了一种适合陀螺马达的能耗制动方案,该方案依据马达逐渐停转时自身产生的微弱电信号,再经放大处理后作为能耗制动的控制信号,实现陀螺马达准确、可靠、平稳的停止,避免了不及时切断电源而烧坏定子绕组的情况.     

GaInP2外延膜中施主—受主对复合发光带的能量关量

通过变温与变激发强度的近红外光致发光研究了用ＭＯＣＶＤ方法、生长在ＧａＡｓ衬底上的Ｇａ０．５Ｉｎ０．５Ｐ（ＧａＩｎＰ２）外延薄膜的１．１７ｅＶ发射带的发光特性。１．１７ｅＶ发光带性质与０．９９ｅＶ及０．８５ｅＶ发光带的性质有着明显的差别。１．１７ｅＶ发光带的机理可用施主－受主对的复合发光来解释，其中施主－受主对系白处在Ｇａ格位上的Ｓｉ（ＳｉＧａ）及其最邻近的Ｇａ空位（ＶＧａ）所组成，记作ＳｉＧａ－ＶＧａ。考虑到ＧａＩｎＰ２中存在着很强的电子－格子耦合作用及其Ⅲ族子格子为部分有序，所以在施主－受主对复合发光中应计及Ｆｒａｎｃｋ－Ｃｏｎｄｏｎ位移△ＦＣ及该对在等效的部分有序势场中的相互作用能Ｅｓ（ＤＡＰ）。Ｘ—射线衍射实验表明，部分有序结构相当于成分调制，因而可用Ｋｒｏｎｉｇ－Ｐｅｎｎｅｙ模型来计算Ｅｓ（ＤＡＰ）值。这样，我们就导出了施主－受主对复合发光的新的能量表示式。     

关于跨声速流动问题的多重解

本文讨论了跨声速流小扰动方程Riemann问题的多重解及物理上可实现的解的判别。