高超声速飞行器二元进气道试验和计算

设计了一种吸气式面对称高超声速飞行器,针对进气道性能,分别在两座风洞开展通流试验研究。针对第1次风洞试验大攻角状态(α=8°)测量值偏离线性的问题,辅助采用数值模拟手段分析原因,并对试验方案进行改进设计,解决了首次试验出现的问题。结果显示,在典型状态(Ma=5~6)下,进气道起动正常,性能良好,具有一定的抗侧滑能力;随来流马赫数增加,进气道流量系数增大,总压恢复系数减小,计算结果和试验结果一致;试验结果和数值计算的差异主要表现为基本测压方案α>4°后,流量系数和总压恢复系数出现严重的非线性。数值模拟结果表明,主要原因为模型支撑方式及测压方式所引起的偏差,通过改进试验方案,解决了大攻角状态下测量值偏离正常趋势的问题。     

Structure and kinetic properties of slow-mode shocks associated with magnetic reconnection in the near-Earth magnetotail

We study the structure and kinetic properties of slow-mode shocks near the plasma sheet boundary layer (PSBL) associated with magnetic reconnection by Cluster observation. The presence of slow-mode shocks is confirmed by traditional Rankine–Hugoniot (RH) analysis and Monte-Carlo shock fitting method. The Walén analysis, applied to the tailward flow associated with slow-mode shocks, also supports that plasma was accelerated across a Petschek-type slow-mode shock connected to the diffusion region. Back-streaming ions were observed on the shock layer, and cold ions were accelerated and heated by slow-mode shocks. In addition, whistler and electrostatic solitary waves were observed around the slow-mode shocks. These waves might be excited by the observed field-aligned electron beams near the shocks.     

Robust speed sensorless induction motor drive

A speed sensorless induction motor (IM) drive with robust control characteristics is introduced. First, a speed observation system, which is insensitive to the variations of motor parameters, is derived based on the concept of sliding mode. Next, an integral-proportional (IP) speed controller using the estimated speed signal is designed to stabilize the speed loop. Then, to preserve the robust control performance under parameter variations and external load disturbance, an adaptive uncertainty observer with feedforward control is proposed. The adaptive uncertainty observer is implemented to estimate the lump of uncertainty of the controlled plant. To increase the accuracy of the estimated values, the speed observation system is implemented using a digital signal processor (DSP) with a high sampling rate     

某型飞机机翼整体油箱工艺研究

介绍了某型机机翼整体油箱的研制过程,针对总体气动、结构和使用维护等对整体油箱提出的性能要求,工程部门相应采用严格的环境措施、确保协调精度的预装配措施以及湿连接、密封装配措施等,解决了研制过程中诸多关键难题,保证了整体油箱的研制进度和产品质量,经各种试验检测和试飞考核,该整体油箱质量稳定可靠,性能良好。     

公允价值在我国新会计准则中的应用及对策

自20世纪90年代以来，公允价值在国际会计准则和美、英等国会计准则中的地位日益凸显，其应用范围一再扩展。受这一趋势的影响，我国于20世纪90年代后期在部分具体会计准则中开始引入公允价值，但公允价值在我国的应用并非一帆风顺，先后经历了“引入、回避、重新引入”的曲折过程。重新引入公允价值成为我国新会计准则的最大亮点，但面临着市场环境不完善、公司治理结构不完善、会计人员素质整体水平偏低、会计监督体制不健全等方面的突出问题。因此，我国应当采取加强公允价值理论研究、加强相关法规制度建设、进一步完善市场环境、完善公司治理结构、加强道德教育与业务培训、完善内部会计控制制度、强化外部审计监督等措施，以促进公允价值在我国的推广应用。     

电磁式舵机的驱动设计试验与仿真

针对一种电磁式舵机,基于虚拟仪器技术设计了相应的测试系统,对舵机的动态性能进行了测试分析。考虑到铁磁阻的非线性和漏磁通的分散性,本文采用磁路微分法建立了舵机电磁铁的数学模型,对其动态特性进行仿真分析。结果表明:舵机的性能满足系统设计要求。试验结果与仿真结果基本一致,仿真计算可以用于舵机性能的优化与分析。     

现代小卫星与大众化空间时代

通过论述现代小卫星技术30年的发展历程,总结其技术发展水平并举出现阶段的典型应用实例,讨论小卫星未来的发展方向,论述大众化空间与现代小卫星的关系,总结现代小卫星技术服务于大众化空间的各项特征。     

一种语音信号欠定盲分离的新方法

文章提出了一种语音信号欠定盲分离的新方法,引入了一种伪提取矢量的概念,并通过在信号采样点处选取对应的伪提取矢量,以恢复取值占优的源信号采样点的值,来实现欠定盲源分离。通过将该方法与传统的基于线性规划的欠定盲源分离方法分别仿真表明:文章所提出方法由于在信号的各采样点处无需优化,因此大大提高了信号分离的速度,语音信号的分离速度比基于线性规划的方法快数倍。     

Experimental investigation and correlation development of jet impingement heat transfer with two rows of aligned jet holes on an internal surface of a wing leading edge

Extensive experimental studies on the heat transfer characteristics of two rows of aligned jet holes impinging on a concave surface in a wing leading edge were conducted, where50000 Rej 90000, 1.74 H/d 27.5, 66° a 90°, and 13.2 r/d 42.03. The finding was that the heat transfer performance at the jet-impingement stagnation point with two rows of aligned jet holes was the same as that with a single row of jet holes or the middle row of three-row configurations when the circumferential angle of the two jet holes was larger than 30°. The attenuation coefficient distribution of the jet impingement heat transfer in the chordwise direction was so complicated that two zones were divided for a better analysis. It indicated that: the attenuation coefficient curve in the jet impingement zone exhibited an approximate upside-down bell shape with double peaks and a single valley; the attenuation coefficient curve in the non-jet impingement zone was like a half-bell shape, which was similar to that with three rows of aligned jet holes; the factors,including Rej, H/d and r/d, affected the attenuation coefficient value at the valley significantly.When r/d was increased from 30.75 to 42.03, the attenuation rates of attenuation coefficient increased only by 1.8%. Consequently, experimental data-based correlation equations of the Nusselt number for the heat transfer at the jet-impingement stagnation point and the distributionof the attenuation coefficient in the chordwise direction were acquired, which play an important role in designing the wing leading edge anti-icing system with two rows of aligned jet holes.     

民用航空犯罪学研究的架构与意义

运用犯罪学的基本理论，提出了研究航空犯罪学的基本架构，在此基础上阐明了研究航空犯罪学的意义。