平流层飞艇的能源技术和平衡分析

平流层飞艇作为近空间对地观测平台的一种实现方案，主要依靠自身庞大体积产生的静浮力而不像其它飞行器依靠相对空气运动产生升力，所以飞艇能够以较慢的速度飞行甚至能够在空中长期保持定点悬停即相对地面静止。具有长时间在平流层自主飞行的能力，是平流层飞艇设计的一个重要目标。文章对平流层飞艇能源系统的构成、部件及能源平衡分析方法作了介绍。     

电子元器件性能与液相外延工艺

分析了液相外延（ＬＰＥ）在微电子工艺中的状况及其原理，概述了ＬＰＥ在器件制造中的应用，指出了ＬＰＥ的电子元器件的优良特性，给出了ＬＰＥ在光电子领域研究中的最新成果。     

等热流条件下相变导热仿生优化

为强化微重力条件下相变材料的熔化释冷过程,采用仿生优化的思想和有限元方法研究了导热空间内高导热材料的最佳布置方案。研究表明,采用温度梯度的时间积分作为布置高导热材料的判断标准,可把导热仿生优化的思想的应用由稳态问题扩展到非稳态具有相变的问题。和人工构造方案法相比,仿生优化得到的方案可以明显强化释冷过程、降低热流入口温升;且能克服其工作量大,所得方案不一定包含最优方案的不完备性问题。     

传像光纤在瞄准方位传递中的应用研究

介绍了光纤传像技术的原理和光纤成像系统的特点，详细分析了传像光纤应用于瞄准方位传递的可行性，并阐述了存在的问题和关键技术的解决。     

GPS total electron content and surface latent heat flux variations before the 11 March 2011 M9.0 Sendai earthquake

The present paper describes the variations of the GPS total electron content (TEC) from the International GNSS service network and surface latent heat flux (SLHF) from the Scientific Computing Division of the National Center for Atmospheric Research (NCAR) before the 11 March 2011 M9.0 Sendai earthquake, respectively. The analysis shows pronounced enhancements in the GPS TEC and SLHF a few days prior to the earthquake event. The maximum increase in the GPS TEC was about 30 TECu with an extended spatial distribution on a geomagnetically quiet day (Dst ? −20 nT, between two moderate geomagnetic storms), 8 March, 3 days prior to the earthquake. This giant positive disturbance was possibly associated with the impending disastrous earthquake and contributed from the enhanced solar radiation. Moreover, there were several anomalous regions of SLHF on the global map, but an area of enhanced SLHF very close to the epicenter. The purpose of this paper is to report the existence of the changes in surface and ionosphere, and show the potential application of multi-source data to identify seismic precursors.     

动态计量技术发展跟踪系列之四 动态温度测量与校准技术

尽管动态温度测量技术得到了快速发展,但由于动态温度测量既与传感器本身结构相关,也与所处工况相关,影响因素众多,因此动态温度的测量仍然难以满足实际的需求。本文对国内外的动态温度测量与校准技术分别进行了介绍,分析了温度传感器动态特性校准的特点,并在此基础上提出动态温度测量与校准技术的发展方向。     

垂直度误差对复合材料单钉连接性能的影响

为揭示连接孔垂直度误差对航空复合材料连接性能的影响规律,对准各向同性碳纤维环氧树脂复合材料板进行了单钉单剪试验研究。以极限承载强度、弦刚度、2%偏移承载强度为指标研究连接孔的倾斜角度、倾斜方向以及螺栓扭矩对接头承载性能的影响规律。试验结果表明:当连接孔倾斜角度从0°增加到4°时,接头弦刚度增大10%~40%,极限承载强度下降9%~12%;连接孔倾斜方向对极限承载强度影响甚微,却可使接头弦刚度产生20%~30%的变化;增加螺栓扭矩可以有效提高极限承载强度,但对接头刚度无明显影响;连接孔倾斜角度越大,则螺栓扭矩的增大对2%偏移承载强度的强化效果越不明显。     

可压缩流体恒温热线风速仪校准方法

开展了恒温(CT)热线风速仪校准方法的研究,以满足可压缩流体中湍流度测量需求。将对数函数与多元回归技术相结合,建立了恒温热线风速仪校准的数学模型,并进行了风洞湍流度测量试验验证。在马赫数Ma=0.3~0.55范围内进行了校准试验,根据建立的数学模型对试验数据进行拟合,拟合优度R2=0.999 82,平均绝对速度偏差Δu=0.18m/s,基本满足了恒温热线风速仪校准精度要求。对马赫数Ma=0.55条件下流场进行了湍流度测量,速度测量偏差为0.034%,流场湍流度Tu=0.14%。试验结果证明了恒温热线风速仪应用于可压缩流体速度测量的可行性。     

基于VB.NET的砝码自动校准系统软件设计与实现

介绍了一种基于VB.NET的砝码自动校准系统软件，能够实现密闭环境中微干扰、高精度、高效率的砝码自动校准工作，并应用于砝码检定校准工作。软件设计采用VB.NET串口通讯、PLC可编程控制器、Access数据库、OLE Office自动化技术，主要实现了砝码自动校准过程设置、砝码信息数据库管理、自动生成实验报告、天平控制、自动校准过程监控等功能。     

Transient simulation of a differential piston warm gas self-pressurization system for liquid attitude and divert propulsion system

In order to obtain the dynamic characteristics of a differential piston warm gas selfpressurization system for liquid attitude and divert propulsion system, a transient model is developed using the modular modeling method. The system includes the solid start cartridge,pressure-amplified tank with liquid monopropellant, liquid regulator, gas generator, and pipes.The one-dimensional finite-element state-variable model is applied to the pipes and the lumped parameter method is adopted for the other modules. The variations of the system operation parameters over time during the startup, steady-state, and pulsing operational processes are obtained from the transient model, and the characteristics of starting time changing with different system parameters are also analyzed. It is shown that the system startup process can be divided into three distinct processes. The starting time monotonically changes with variations of the liquid regulator parameters, first decreasing and then increasing with the mass change of the solid propellant charge of the start cartridge, initial gas cavity volume of the pressure amplified tank and initial gas cushion of the propellant tank. The starting time can be reduced to less than 1.0 s(0.68–0.75 s for the current system). For meeting the deviation requirements of ±10% of the steady-state propellant tank pressure, the positive deviation requirement is assured by the self-locking pressure and the negative deviation can be assured within an allowable maximum propellant tank volume flowrate(1.6 times the design value for the proposed system) for downstream thrusters for a designed system. The results from the simulation are useful as a guide for further system design and testing.