宇航元器件电磁兼容性评估技术研究

随着元器件的集成度越来越高和功能日趋复杂,元器件的电磁兼容性(EMC)问题也愈加突显,元器件的EMC特性是评价元器件系统适应性的一个重要方面。国外宇航机构已经开展了元器件的EMC特性研究,并制定了相关标准。但在国内,无论是元器件生产厂还是元器件用户,均未对元器件的EMC特性进行系统的考核评价,给不出元器件的EMC指标。通过分析研究国内外元器件EMC评估技术发展情况,结合国内宇航元器件研制现状,从宇航应用角度出发,提出了较为规范的宇航元器件EMC评估方法和流程,并通过试验验证了该方法的可行性。     

宇航元器件制造成熟度验证

对国外新技术元器件验证、评估及鉴定要求进行了分析,介绍了NASA新技术元器件的验证现状,提出了宇航元器件制造成熟度验证的建议,可供后续宇航元器件应用验证工作借鉴。     

覆盖全过程的宇航元器件认定技术流程研究

介绍了一种覆盖需求-研制-应用全过程要素的宇航元器件认定技术流程,首次将用户需求、生产厂研制过程和元器件评估,以及应用验证等全过程要素集中地体现在认定技术流程中。与以往元器件质量保证多关注元器件试验不同,此技术流程将关注点前后延伸:向前延伸到生产厂元器件研制;向后延伸至模拟宇航型号使用条件进行的应用验证和指导型号设计师选用。可为元器件在宇航工程的应用提供翔实的数据支撑和参考依据。     

宇航元器件在轨测试研究

对国内宇航元器件应用现状进行调查研究,阐述了宇航元器件进行在轨测试的必要性。对宇航元器件在轨测试的方法进行探讨,列举了目前常用的在轨测试方法。重点对宇航元器件进行在轨测试参数选择,对实施方案进行分析,同时对航天元器件在轨参数进行了研究。随着航天事业不断发展,宇航元器件在轨测试将会得到更多的关注和应用,将为实现宇航元器件的自主发展打下基础。     

低等级元器件在宇航型号应用的可靠性评估方法

随着航天技术的快速发展,对电子元器件的功能和性能要求也越来越高,而目前高质量等级电子元器件的研制和应用相对落后,不能满足宇航型号的使用需求。迫切需要吸纳一些功能和性能满足需求的低等级元器件,但这些低等级元器件的可靠性实验要求、辐照实验要求和工艺要求等可能存在不满足宇航型号要求的情况,或者没有可靠性的数据支撑,无法直接使用,需要对这些低等级元器件进行可靠性的评估。本文针对低等级电子元器件在某宇航型号应用的问题进行了分析,并对低等级元器件在航天应用的可靠性评估方法和试验方法做了研究和分析总结。     

宇航元器件力学环境适应性评价技术研究

从宇航工程实际应用出发,以环境工程理论为基础,研究了宇航元器件装机条件下的力学环境失效案例和敏感要素,综合考虑宇航产品相关力学环境试验项目、试验组合、试验剖面与判据,并通过试验分析和总结,建立了宇航元器件应用验证力学环境适应性评价方法和流程,形成了宇航元器件应用验证力学环境适应能力的分级量化判据,并进行了相关的试验验证。     

宇航用元器件采购规范发展趋势分析

在分析国内外元器件通用规范及采购规范的基础上,针对国内元器件生产现状、宇航应用情况及未来需求,对宇航用元器件采购规范发展现状进行综合分析,提出我国宇航用元器件采购规范的技术发展方向。     

宇航元器件搭载试验研究与实践

元器件搭载是国内外航天器,特别是新技术试验卫星中的一类重要试验项目,也是推动元器件成熟和宇航应用的重要手段。从元器件搭载试验验证体制、天地联合验证方法、试验组织、试验结论发布和应用等方面,对元器件搭载试验提出了总体策略,对搭载试验任务内容和要求进行了分析,总结了元器件搭载试验的实践。研究工作对我国宇航元器件搭载试验相关工作具有较高的参考价值。     

宇航元器件应用验证指标体系构建方法研究

通过分析宇航元器件应用验证指标体系的特点,建立了一套面向宇航元器件应用验证的指标体系构建方法,该方法分别应用专家遴选系统、头脑风暴法和德尔菲法,解决了宇航元器件应用验证指标体系构建中的专家遴选、因素识别和指标体系构建问题。最后,应用该方法建立了宇航元器件应用验证综合评价指标体系基本结构。     

宇航元器件应用验证指标体系构建方法研究

通过分析宇航元器件应用验证指标体系的特点,建立了一套面向宇航元器件应用验证的指标体系构建方法,该方法分别应用专家遴选系统、头脑风暴法和德尔菲法,解决了宇航元器件应用验证指标体系构建中的专家遴选、因素识别和指标体系构建问题。最后,应用该方法建立了宇航元器件应用验证综合评价指标体系基本结构。     

Ultrasonics in nondestructive evaluation

The use of ultrasonic waves in nondestructive evaluation is reviewed. Perspective is provided by a summary of the role played by nondestructive evaluation in the manufacture and utilization of structural components. Included are discussions of the methodologies for predicting part serviceability and of the constraints placed on the nondestructive measurement process by the mechanical designs and functions of structural components. The principles of active (ultrasonic) and passive (acoustic-emission) testing techniques are then reviewed. Specific examples of applications from several industries illustrate the capabilities and limitations of state-of-the-art techniques based on these principles. Detailed discussion is then given of present research and development activities designed to overcome these limitations, with particular emphasis on those areas best addressed by the tools of electrical engineering. Included are discussions of instrumentation, inspection performance modeling, flaw sizing techniques (including imaging systems), material property measurement techniques, and acousticemission techniques. The paper concludes with a consideration of important directions of future work.     

航天用DC/DC电源模块结构分析研究

结构分析作为一种可靠性评估方法,它通过分析元器件的设计和结构工艺来确定元器件是否存在潜在的失效机制,对于高可靠应用领域元器件的质量保证起着重要的作用。DC/DC电源模块是航天器广泛使用的重要元器件,它的长期可靠性和稳定性直接关系着航天器的在轨安全。对航天用DC/DC电源模块的结构分析方法进行了研究,并给出了它的关注点和试验方法及其重要的判据,为航天用DC/DC电源模块的结构分析提供重要的指导。     

Systematic evaluation and analysis for 60-GHz dielectric resonatorscoupled to a microstrip line on a GaAs substrate

This paper presents the first systematic evaluation and analysis of 60-GHz-band TE_01δ-mode cylindrical dielectric resonators coupled to a microstrip line on a GaAs substrate. The loss components of the unloaded Q are analyzed using simple numerical techniques. The distance between the resonator center and the microstrip line which gives the maximum coupling coefficient is found to be approximately 3/5 of the resonator radius, whose ratio is almost constant for all practical cases. The temperature characteristics are also demonstrated and the origins of temperature dependences of the unloaded Q and the coupling coefficient are discussed. An equivalent circuit model for the dielectric resonator coupled to the microstrip line is presented, whose element parameters can express the dependences of the resonant frequency, the unloaded Q, and the coupling coefficient on the structural parameters and the temperature     

小波域结构相似度融合图像质量评价方法

针对融合图像质量评价问题,分析了图像质量评价与融合图像质量评价的关系,给出了融合图像质量评价方法的一般表达公式,指出构造实际并不存在的参考图像是解决融合图像质量评价问题的关键。在此基础上,基于空域结构相似度评价方法,对输入源图像和融合图像分别进行小波分解,利用输入源图像小波分解系数构造参考图像小波系数,然后根据人眼视觉敏感度带通特性对参考图像和融合图像的各小波频带进行加权,从而得到整幅图像的小波域结构相似度评价指标,利用目标可探测性、细节可分辨能力和图像整体舒适性构成主观评价指标分别和交互信息量、基于空域的结构相似度比较。实验结果表明,相比于传统的客观评价方法,提出的方法所得结果与主观评价结果的一致性更好。     

结构分析技术在行波管可靠性评估中的应用

结构分析是一种重要的元器件可靠性评估方法,可以评估元器件内是否存在潜在的缺陷。行波管结构分析可以为行波管固有质量和固有可靠性的判断提供重要依据。探讨了结构分析技术在行波管可靠性评估中的应用,给出了行波管结构分析的一般试验流程、一般技术流程、分解原则以及典型的结构单元分解,并提出了行波管结构分析中应注意的几个问题。     

Fully automated reduction of ocular artifacts in high-dimensional neural data

The reduction of artifacts in neural data is a key element in improving analysis of brain recordings and the development of effective brain-computer interfaces. This complex problem becomes even more difficult as the number of channels in the neural recording is increased. Here, new techniques based on wavelet thresholding and independent component analysis (ICA) are developed for use in high-dimensional neural data. The wavelet technique uses a discrete wavelet transform with a Haar basis function to localize artifacts in both time and frequency before removing them with thresholding. Wavelet decomposition level is automatically selected based on the smoothness of artifactual wavelet approximation coefficients. The ICA method separates the signal into independent components, detects artifactual components by measuring the offset between the mean and median of each component, and then removing the correct number of components based on the aforementioned offset and the power of the reconstructed signal. A quantitative method for evaluating these techniques is also presented. Through this evaluation, the novel adaptation of wavelet thresholding is shown to produce superior reduction of ocular artifacts when compared to regression, principal component analysis, and ICA.     

空间相机大型轻质框架的选型与设计

针对某空间相机的光学设计结果,基于不同材料的机械加工特性,设计了几种结构形式的框架并进行了选型。采用有限元法对各框架的谐振频率进行了分析,对框架的经济性也进行了分析,最终确定了框架的结构形式。选定的框架为全桁架杆结构,重量为57 kg,一阶谐振频率为90.4 Hz。框架组件的力学试验验证表明,其一阶谐振频率为88.7 Hz。分析和试验结果均表明,该框架能够满足设计要求。     

A model-based method for the reconstruction of total knee replacement kinematics

A better knowledge of the kinematics behavior of total knee replacement (TKR) during activity still remains a crucial issue to validate innovative prosthesis designs and different surgical strategies. Tools for more accurate measurement of in vivo kinematics of knee prosthesis components are therefore fundamental to improve the clinical outcome of knee replacement. In the present study, a novel model-based method for the estimation of the three-dimensional (3-D) position and orientation (pose) of both the femoral and tibial knee prosthesis components during activity is presented. The knowledge of the 3-D geometry of the components and a single plane projection view in a fluoroscopic image are sufficient to reconstruct the absolute and relative pose of the components in space. The technique is based on the best alignment of the component designs with the corresponding projection on the image plane. The image generation process is modeled and an iterative procedure localizes the spatial pose of the object by minimizing the Euclidean distance of the projection rays from the object surface. Computer simulation and static/dynamic in vitro tests using real knee prosthesis show that the accuracy with which relative orientation and position of the components can be estimated is better than 1.5 degrees and 1.5 mm, respectively. In vivo tests demonstrate that the method is well suited for kinematics analysis on TKR patients and that good quality images can be obtained with a carefully positioning of the fluoroscope and an appropriate dosage. With respect to previously adopted template matching techniques, the present method overcomes the complete segmentation of the components on the projected image and also features the simultaneous evaluation of all the six degrees of freedom (DOF) of the object. The expected small difference between successive poses in in vivo sequences strongly reduces the frequency of false poses and both the operator and computation time.     

Apport de l’analyse technologique à l’enseignement de la microélectronique

The technological analysis of electronic components uses different sample preparation and observation techniques which are able to give deep informations about the integrated circuit and technologies. The purpose of this paper is to propose, through a visual document, a method to illustrate realistically a microelectronic course. This approach seems to be especially appropriate for circuits and équipement engineer education, requiring a focussing towards IC’s evaluation and choice.