宽直线连接的处理方法

宽直线广泛应用于工程制图、PCB板图绘制等方面,宽直线的效果直接影响着最终输出图形的质量。宽直线的生成涉及许多问题[1],线接头是宽直线生成过程中必须要处理的问题之一,通过使用本文所介绍的两种方法,能有效解决宽直线圆连接和斜切连接的问题,并能获得所希望的效果。     

微放电效应预测研究

分析了几种类型结构方同轴线的特性,利用FDTD数值方法对方同轴线的微放电效应阈值电平进行预测计算,并给出了阈值曲线.结合实验数据说明了预测方法是有效的,该阈值曲线可以作为微放电效应部件设计参考曲线.     

CBERS-02星红外数据系统正反扫描行配准方法研究

CBERS-02星搭载的有效载荷有一台是红外多光谱扫描仪(IRMSS),它是摆扫式的相机,与推扫式的CCD相机成像方式不同。摆扫式IRMSS相机的几何校正处理对比推扫式相机更为复杂,特别是正反扫描行之间,容易出现不配准、有缝隙或叠加等问题。文章根据IRMSS成像的机理,对CBERS-02星IRMSS图像存在的扫描行不配准问题进行了改进,达到了良好的效果。     

基于实际切齿方法的螺旋锥齿轮建模与实体设计

基于螺旋锥齿轮副中大轮采用的半滚切法加工原理,提出一种螺旋锥齿轮建模方法,推导出内、外齿顶线方程。应用MATLAB求解齿顶线方程,将结果导入SolidWorks软件生成曲线,基于扫描切除特征得到螺旋齿面,建立了螺旋锥齿轮的三维实体模型。最后通过具体实例说明了实体设计过程。     

FUV and X-Ray Absorption in the Warm-Hot Intergalactic Medium

The Warm-Hot Intergalactic Medium (WHIM) arises from shock-heated gas collapsing in large-scale filaments and probably harbours a substantial fraction of the baryons in the local Universe. Absorption-line measurements in the ultraviolet (UV) and in the X-ray band currently represent the best method to study the WHIM at low redshifts. We here describe the physical properties of the WHIM and the concepts behind WHIM absorption line measurements of H i and high ions such as O vi, O vii, and O viii in the far-ultraviolet and X-ray band. We review results of recent WHIM absorption line studies carried out with UV and X-ray satellites such as FUSE, HST, Chandra, and XMM-Newton and discuss their implications for our knowledge of the WHIM.     

Manifestation of magnetic reconnection in coronal streamer current sheets

We investigate the possibility of observing the effects of magnetic reconnection inside a current sheet forming in a coronal streamer in the extended corona. In particular we study the possibility to observe with the UVCS of SOHO the excitation of the tearing instability in the current sheet.     

The gamma-ray observatory mission objectives and its significance for gamma-ray astronomy

The Gamma Ray Observatory (GRO) is an approved NASA mission, programmed for launch in 1988. Its complement of four detectors has established goals: 1) to study the nature of compact γ-ray sources such as neutron stars and black holes, or objects whose nature is yet to be understood; 2) to search for evidence of nucleosynthesis especially in the regions of supernovae; 3) to study structural features and dynamical properties of our galaxy; 4) to explore other galaxies, especially the extraordinary types such as radio, Seyferts, and quasars; and 5) to study cosmological effects by examining the diffuse radiation in detail. This paper discusses the design, objectives, and expected scientific results of each of the GRO instruments in view of the GRO mission goals.     

Observational evidence for non-equilibrium ionization in the solar corona

We investigate whether temperature sensitive EUV line ratios can be used as observational signatures for the presence of non-equilibrium ionization in transition region plasma. We compute the total intensity of some EUV lines of carbon and oxygen expected from coronal loop models with a steady-state flow and which are known to have significant departures from ionization equilibrium, selecting lines whose intensity ratios are useful for deducing the electron temperature in the coronal plasma. We calculate the intensity ratios with and without the approximation of ionization equilibrium, in order to determine the effects of any deviations from equilibrium on the numerical values of the line ratios examined.     

B737NG飞机真空废水排放管路再循环法清洁

飞机真空废水排放管路常因管路内壁堆积废物导致堵塞,进而降低真空排污系统的功能。为有效减少管路内废物堵塞对真空排污系统的影响,波音公司收集多家运营商对真空废水系统的维护经验及反馈,提出再循环法清洁废水排放管路可以有效预防和减少排污管路内废物的堆积。再循环法主要通过化学浸渍和机械冲洗除去废水管内积聚的污物,是一种预防性维护措施,可提高真空排污系统的使用周期。     

Nucleosynthesis from non-thermal particles

The long-standing problem of nucleosynthesis from non-thermal charged particles is reviewed with emphasis on some novel points. Recent theoretical results predict very efficient acceleration of nuclei (up to GeV range) by violent systems with energy release in the form of multiple shock waves —OB associations and coronae of AGNs and black holes candidates in galactic accretion disks. A detection of gamma-line emission from the Orion complex by theCOMPTEL telescope on board ofGRO could confirm theoretical predictions. Production of lithium by non-thermal particles in Orion-like objects is discussed. The mechanism can be responsible for the observed variations of abundance of isotopes.