基于磁场映像的印制电路板故障诊断方法研究

简要分析了印制电路板的电磁场，提出了用电磁感应法测量磁场的电咱故障诊断新方法，并给出了测试系统组成方案。最后通过验证实验证明了该方法是确实可行的。     

EUV emission from normal galaxies

Using data from the Wide Field Camera EUV all-sky survey, we have established upper limits to the EUV flux from a sample of 30 bright, nearby, non-active spiral galaxies. These galaxies were chosen to be those most likely to be detected in the EUV on the basis of (i) low interstellar absorption within our own galaxy, (ii) brightness in other wavebands, (iii) high star formation activity, and (iv) proximity. The derived EUV upper limits are restrictive, and establish for the first time that the EUV flux escaping from galaxies does not constitute a major component of their bolometric luminosity, and in particular that it cannot be the sink for the energy injected into the interstellar medium by supernova explosions, as had been suggested following the failure to detect this power in the X-ray band.     

A bistatic SAR mission for earth observation based on a small satellite

The authors present a new scientific space mission consisting of a satellite carrying a receiving- only SAR which receives the signal transmitted by the ENVISAT-1 SAR. The integration of ENVISAT-1 SAR and bistatic radar data offers an improved potentiality of surface classification, three-dimensional observation, and the opportunity of advanced scientific experiments in the field of bistatic scattering. The small satellite nominal orbit and the attitude manoeuvres are designed in order to maintain an adequate overlap between the two radar swaths along the whole orbit, taking into account the ENVISAT-1 attitude and pointing. A preliminary satellite design (2-year lifetime) is then performed to evaluate the orbit decay and to determine the appropriate orbit manoeuvres (every 4 days) to control the satellites relative phase. The numerical simulation shows that a spacecraft of about 584kg is able to meet the mission requirements.     

一类非线性边值问题的激波解

研究了一类非线性奇摄动方程。首先得到了外层解，利用特异极限阶定了激波层的几种可能位置，对激波层的几种不同位置利用伸长变量构造出内层解。最后利用匹配原则求出了原方程在整个区间上的渐进解。     

金融工程对我国国有银行信用风险管理的启示

多年来信用风险都是各国银行所面临的主要风险,由于历史的原因我国国有银行的信用风险管理问题显得更为突出.针对国有银行信用风险管理现状,引入最新的金融工程的方法和理念,从技术创新和制度创新的角度对国有银行的信用风险管理提出建议.     

GPS based onboard and onground orbit operations for small satellites

In extension to common applications such as groundtrack displays and antenna steering, the SGP4 orbit model is proposed for operational orbit determination in small satellite missions. SGP4 is an analytical orbit model for Low-Earth orbiting satellites that is widely used for the propagation of NORAD twoline elements. Twoline elements may hence be generated completely independent of NORAD. Their use as exclusive source of orbital information simplifies the operations concept and reduces mission costs through the extensive use of existing low-cost mission support software. Due to small computer resource requirements of 8–10kByte, the SGP4 model may also be applied for onboard orbit computations making use of e.g. a 80186 processor, thus ensuring full compatibility of ground-based and onboard operations. The proposed approach is particularly suited in combination with a space-borne GPS receiver, were the C/A-code navigation solutions are treated as measurements that are adjusted in a least-squares sense using the SGP4 model. As consequence, inherent drawbacks of the pure navigation solutions such as data gaps and scatter as well as limited velocity accuracy are avoided, while the operational navigation activities are kept at a minimum. The feasibility of the concept is illustrated based on real GPS navigation data from the TOPEX/Poseidon and the MIR space station with an inherent data quality of 50–100 m. It is shown that 3 hours of data within a 4 day period are sufficient to keep the position error within 4 km, that is considered sufficient for most applications.     

k-ε-g紊流燃烧模型数值研究

本文对k-ε-g紊流燃烧模型中模型系数C_R,C_(g1),C_(g2)的选定和计算浓度脉动均方值g的不同方法进行数值研究。计算结果表明模型系数值的选定直接与化学反应速率有关,而其中C_R影响最大。g的计算虽然可有不同方法,而其中微分方程求解最佳。并用实验数据来验证计算结果。     

多点法测量形状误差的补偿控制系统

经过对误差分离技术理论进行了分析之后,又对误差补偿技术进行了研究,并建立了多点法测量形状误差的补偿控制系统。通过补偿主轴径向误差运动,提高了工件的圆度误差和圆柱度误差。     

一种新型的微机补偿晶体振荡器及开发系统

提出了一种新型的以微处理器为核心的AT切温度补偿晶体振荡器 (MCXO)的设计思想 ,说明了其开发系统的原理 ,给出了最后的实验结果。使用该开发系统得到的这种振荡器可以工作在 - 40℃～ 85℃的环境内 ,频率—温度稳定性≤± 5× 10 - 7。     

管理信念对企业绩效的影响——基于劳动关系和谐度的中介效应

随机抽取广州市2 905家企业人事经理的管理信念、劳动关系和谐度、企业经济绩效和非经济绩效的问卷调查数据进行多重回归,检验中介效应,并比较守法企业与非守法企业的差异.结果发现:(1)守法企业与非守法企业在管理信念、劳动关系和谐度、企业经济绩效和非经济绩效的表现上均存在极其显著的差异;(2)管理信念对企业经济绩效和非经济绩效都有正向性的影响;(3)企业的劳动关系和谐度发挥积极的中介作用.