数字射线成像中射线对面阵 CCD图像传感器影响的研究

目的 研究数字射线成像系统中X射线对CCD图像传感器及其系统成像质量的影响方式、特点以及图像质量的改善算法。方法 利用实验手段,对CCD图像传感器区域上的受摄像影响的像素数进行了统计,并对统计的结果进行了分析。结果与结论 在DR系统中,x射线对CCD产生的影响直接造成了图像上的单像素、高幅值的尖峰脉冲,针对这种噪声特点,文中介绍了两种滤波算法。     

X射线探伤室的辐射防护

近年来,随着经济的发展,科学水平的提高,各行各业对X射线探伤作业越来越依赖,使用的频率也逐渐在增加,人们对X射线探伤室的辐射防护的要求也越来越重视。经通过分析研究得知X射线在探伤室的工作方式主要是以主射、散射及漏射等途径对工作场所以及周围的环境产生它的辐射效应。所以,本文主要是把X射线探伤室自身的辐射防护能力和对探伤工作的人员以及对周围的公众人员的辐射产生的影响进行分析作为阐述重点。     

星用光纤通信系统中的发光二极管的总剂量效应研究

介绍了星用光纤通信系统中的发光二极管在 6 0 Co- γ射线辐照下的总剂量效应试验研究 ,通过对不同剂量辐照情况下发光二极管的发光光谱、伏安特性及 P- I曲线进行测试 ,给出了在不同剂量的 γ- 6 0 Co射线辐照下发光二极管的发光光谱、伏安特性及 P- I曲线     

铁氧体材料辐射效应的研究进展

随着航空航天技术和核技术的发展,铁氧体电子元器件已经广泛运用于人造卫星、宇宙飞船和核污染探测器等。基于空间环境和核环境的特殊性,铁氧体电子元器件不可避免地处于空间辐射和核辐射等强辐射环境之中,然而辐射会对铁氧体电子元器件性能造成不同程度的损伤甚至导致器件失效。介绍了铁氧体材料和辐射环境,着重综述了近年来国内外铁氧体材料辐射效应的研究,分析了不同种类的辐射对铁氧体材料性能的影响,指出了研究铁氧体材料辐射效应存在的问题,并展望了今后值得关注与研究的方向。     

大气等离子喷涂制备Fe-Ni-B合金涂层-321不锈钢层状复合材料的射线屏蔽性能研究

为满足核辐射屏蔽材料对结构-功能一体化的需求,采用大气等离子喷涂工艺在321不锈钢基体上设计并制备了Fe-Ni-B合金涂层复合材料,用于防护从裂变反应堆释放的中子与γ射线。在介绍该层状复合材料设计与制备的关键参数与技术细节的基础上,主要研究了层状复合材料对中子及γ射线的屏蔽性能。研究结果表明,该层状复合材料具有结构-功能一体化特征,理论计算及测试结果对比分析表明该材料对中子及γ射线拥有良好的综合屏蔽能力,有望在各种核辐射反应堆屏蔽系统中使用。     

旋转式CCD漂移扫描观测的控制模型研究

采用CCD漂移扫描技术可以显著提高地基光电望远镜系统的观测效率,改善空间目标的数据质量,但目前不适合对快速移动目标的观测.把CCD漂移扫描技术与精密控制的旋转装置相结合是扩展其应用的一种解决思路,本文在分析CCD漂移扫描技术的基础上,建立了一种旋转式CCD漂移扫描观测的控制模型.同时运用模型进行了模拟观测实验,并分析了旋转角度、脉冲控制周期等模型参数对观测效果的影响,其结果不仅验证了该旋转控制模型构造的合理性,而且也能为实际观测提供参考依据.     

交会对接杂散光分析及反杂光干扰措施设计

在空间交会对接过程中,太阳等各种天体以及飞行器上零部件的辐射与反射都会影响CCD的成像,形成大量杂散光干扰。阳光效应是很多其它杂散光干扰的源,如果不采取特殊措施,标志灯的像点可能会全部被阳光效应所淹没。本文通过对阳光效应包括阳光直射、阳光斜射和阳光漫射效应的分析,提出了两项反杂光干扰措施:标志灯的发光器件工作在红外波段;在摄像机光路系统中安装特殊设计的窄带干涉滤光片。实验表明,上述反杂光干扰措施能够有效地滤除阳光、月光、星光、灯光以及其它非标志灯工作波段杂光的干扰。     

水性环氧耐核辐射涂料的制备

以环氧改性胺乳液为A组分,环氧树脂为B组分,制备了性能优异且环保的水性环氧耐核辐射涂料。研究了环氧改性胺乳液、耐核辐射颜填料及颜料体积浓度(PVC)等因素对涂料性能的影响。结果表明,采用环氧改性芳香胺为固化剂,配合功能性填料钛酸钾晶须制备的水性环氧耐核辐射涂料具有优良耐辐照性能及去污性能,经过8.5×105GY(累积剂量)辐照后漆膜完好,附着力良好。     

地球表面热红外辐射的方向效应

利用装有红外辐射计的测角系统研究了自然地表面的红外辐射的方向特征, 检测了几种典型自然地表面的地面温度的角度关系. 地面亮度温度的测量值随观测天顶角、方位角和太阳位置而改变. 草地上的测量反映了植被覆盖典型的方向特征;在粗糙土壤地面上, 当太阳辐射方向与观测方向十分接近时, 观测到了"热斑效应";在人造土坡上, 测量到较大的亮度温度的角度变化;而在平静水面的观测中, 当水面未处于辐射热平衡状态时, 在观测天顶角小于 60°时, 没有观测到发射辐射的角度效应. 这些结果表明: 地面红外辐射方向特征引起的亮度温度的差异与地形及太阳辐射在地表面上的反射方向效应有关. 这些方向变化的特性可导致卫星遥感地面温度反演的偏差.     

为应对核泄漏危机提供计量技术保障

随着日本强震引发海啸造成福岛核电站核泄漏事故的发生,我国启动了海陆空全方位的环境核辐射监测、核设施安全检查,实时公布核辐射监测结果。国家质检总局已要求各地检验检疫机构加强对放射性物质入境的风险分析,切实做好口岸核与辐射物质监测工作。用于辐射监测的仪器设备的量值是否准确可靠将直接影响测量结果和数据发布,关系到辐射安全与公众的健康安全,因此就显得尤为重要。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.