加速度-气动力综合试验系统研制

加速度-气动力综合试验系统主要用来考核飞行器结构强度和内装物的环境适应性。LJ-1离心机半径10.8 m,适合开展大尺寸、危险品加速度试验,但是其吊篮只能固定在水平或竖直方向上,也不具有与加速度协调施加气动外压的控制系统。文章采用新颖的胀套锁紧结构,实现了吊篮在任意角度固定,并且抗翻转力矩达到13000N·m。气动力控制电路和气路安装在离心机上,上位机将转速通过光纤以太网发送给离心机上的PLC,PLC根据加速度控制气囊压力。试验验证LJ-1离心机具有对试件施加加速度载荷和气动力的综合试验能力。     

高职实用英语课程教学改革与实践研究

从事航空机务类的从业人员要求有较高的英语水平,通过分析高职院校航空机务类英语课程教学改革实施前的情况,从英语课程教学体系、英语课程内容设置、英语教材、英语教学团队四个方面着手,重点探讨了航空机务类英语课程教学改革的具体实施过程。此外,从学生的可持续学习能力、各类竞赛所取得的成绩、就业竞争力三方面总结了课程教学改革所收到的成效,同时对后续研究提出了拓展性建议。     

河北省大学生生命质量状况与健康促进策略研究

本课题采用问卷调查法对河北省普通高校978（男608,女370）名大学生的生命质量与体育锻炼因素问的关联研究进行调查。结果显示：男大学生的生命质量高于女生,并存在显著性差异。造成这些差异的主要原因可能是与体育锻炼因素不同有关。体育锻炼与健康知识、态度、信念和行为对大学生命质量性别差异影响较大。     

用于单晶叶片应力分析的滑移本构模型

为了建立适用于镍基单晶涡轮叶片的有限元分析平台,基于有限变形晶体滑移理论和有限元软件AN-SYS接口参数要求,导出了增量型本构方程公式。采用变刚度法,以切线系数法为初值,采用局部牛顿拉弗森迭代解法,编制了晶体弹塑性滑移本构模型程序,并以子程序Usermat的形式植入ANSYS软件。计算模拟了DD3试棒不同取向的单向拉伸和循环应力应变过程,讨论了〈011〉方向上的应变软化行为和该本构模型对DD3镍基单晶涡轮叶片的良好应用性。数值仿真结果与实验数据对比吻合良好,验证了程序的正确性。     

Sensor Optimization Selection Model Based on Testability Constraint

Sensor selection and optimization is one of the important parts in design for testability. To address the problems that the traditional sensor optimization selection model does not take the requirements of prognostics and health management especially fault prognostics for testability into account and does not consider the impacts of sensor actual attributes on fault detectability, a novel sensor optimization selection model is proposed. Firstly, a universal architecture for sensor selection and optimization is provided. Secondly, a new testability index named fault predictable rate is defined to describe fault prognostics requirements for testability. Thirdly, a sensor selection and optimization model for prognostics and health management is constructed, which takes sensor cost as objective function and the defined testability indexes as constraint conditions. Due to NP-hard property of the model, a generic algorithm is designed to obtain the optimal solution. At last, a case study is presented to demonstrate the sensor selection approach for a stable tracking servo platform. The application results and comparison analysis show the proposed model and algorithm are effective and feasible. This approach can be used to select sensors for prognostics and health management of any system.     

有限维修渠道约束下多级维修供应系统库存控制

多级维修供应管理是提高装备保障效能的有效途径,备件的筹措和规划是影响装备可用度和形成战斗力的关键因素。在可修备件库存控制的多等级(METRIC)理论的基础上,放宽了模型中"无限维修总体"的假设条件,根据M/M/C排队论,对故障件的平均维修周转时间及备件供应渠道进行了修正,建立了备件的初始库存优化模型。在传统边际优化算法的基础上,通过引入分层优化的思想,对算法进行改进,使算法具有更高的运算效率,并在理论上对其进行了证明。算例结果表明:在保证计算结果完全一致的基础上,改进的分层边际优化算法能够大大提高运算效率。     

BOC导航接收机伪码测距零值分析

伪码测距零值是现代卫星导航领域的重要指标,目前对于高精度BOC导航接收机的信道建模和仿真尚没有一般性的量化分析方法。针对这种情况,提出了基于副载波相位消除跟踪算法的零值估计模型,并推导了任意信道特性滤波器与伪码测距零值的关系式,然后定量地分析了信道特性对于测距零值的影响;最后在软件接收机上进行了仿真检验。     

《电子产品分析与制作》学习领域课程构建与实施

对工作过程导向的应用电子技术专业课程体系进行探讨,提出构建工作过程导向的《电子产品分析与制作》课程的基本原则,在此基础上进行课程的具体内容和过程的构建,提出导向性学习、自主性学习、工作情境实战性学习的分层递进的实施策略。     

Exploring for natural gas using reflectance spectra of surface soils

Reflectance spectra in the visible and near-infrared wavelengths provide a rapid and inexpensive means for determining the mineralogy of samples and obtaining information on chemical composition. Hydrocarbon microseepage theory establishes a cause-and-effect relation between oil and gas reservoirs and some special surface anomalies, which mainly include surface hydrocarbon microseepage and related alterations. Therefore, we can explore for oil, gas by determining reflectance spectra of surface anomalies. This idea has been applied to the R&D project of exploring for natural gas in Qinghai province of China using NASA EO-1 satellite with the Hyperion sensor (June 2005 to June 2006). In this project, in order to improve the accuracy of exploration targets of natural gas mapped in the field studied, an integrated practical system of exploration of oil and gas was built by the analysis of not only hyperspectral remote sensing data but also data provided from field work. In this paper, our efforts were focused on the analysis of the 799 reflectance spectra provided from the field work. In order to properly define the typical form of hydrocarbon microseepage with spectroscopy and fulfill the data analysis, it was necessary to build a spectral model. In this spectral model the most important features of hydrocarbon microseepage in the surface of our study area, i.e., diagnostic spectral macroscopic features and diagnostic spectral absorption features, were proposed and extracted, respectively. The distribution of coexisting anomalies, which results from both alteration minerals and hydrocarbons, is estimated by the diagnostic macroscopic features mainly using Spectral Angle Mapper (SAM) classifier. On the other hand, the diagnostic absorption features of two main absorption bands presented abundant local information, based on deep analysis of which, we are able to map the anomalies of alteration minerals and hydrocarbons, respectively. Additionally, a general framework of analysis and key classification algorithms applied to the Hyperion data have been introduced briefly. In our work, three exploration targets of natural gas were identified from the study area which covers 2100 km². In the three exploration targets, three wildcats have been drilled by China National Petroleum Corporation (CNPC) since July 2006, and all the three wells have been proven some industrial reserves.     

Ionosphere tomography based on spaceborne SAR

Two models of ionosphere tomography based on spaceborne SAR (Synthetic Aperture Radar) are proposed. For HF-SAR the signal with sweeping frequency lower than the characteristic frequency of ionosphere will be scatted during the ionosphere propagation and completely reflected at a corresponding height. The ionospheric electron density isolines looked as series of random surfaces can be reconstructed from the HF-SAR echoes by using the inverse scattering technique for layered rough surfaces and the method of moment (MoM). The numerical simulation show that due to the MoM can provide a full wave solution, the ionosphere tomography with high resolution can be obtained as long as enough sampling data of HF-SAR echoes are used. For VHF/UHF/P/L-band SAR the TEC (Total Electron Content) can be obtained from the SAR echoes scattered by some strong point targets (such as the calibrators, etc.) appeared in the SAR imaged ground region, and the ionosphere tomography can be performed by CT technique.