X射线平板探测器数字成像及其图像校准

为了提高X射线数字成像系统的图像质量,以基于平板探测器的X射线数字照相系统为研究对象,介绍了平板探测器自身影响图像质量的4大因素:随机噪声,偏置误差,像元响应不一致性和瑕疵像元等,分析了这些因素的成因及其对图像质量的影响,提出了相应的减小和消除这些影响的图像校准方法.实验结果表明:运用这些图像校准方法,可以有效地去除上述因素对图像质量的影响,显著提高平板探测器输出图像的质量,为后续图像判读奠定了良好的基础.      

A 3NM-64_He added to LARC for Solar Extreme Event studies during solar cycle 24

The Antarctic Laboratory for Cosmic Rays (LARC, acronym for Laboratorio Antartico per i Raggi Cosmici or Laboratorio Antártico para Rayos Cósmicos) operates on King George Island (South Shetlands). Since January 1991 a standard 6NM-64 detector has been recording continuous cosmic ray measurements and several Ground-Level Enhancements have been registered. Here we describe the different phases performed in Italy for the realization of a 3NM-64_³He detector, which started its measurements during the Italian XXII Antarctic Summer Campaign. Data recorded during solar activity cycle 24 will furnish an useful research tool for the next Solar Extreme Events.     

The radiation environment in the ISS-USLab measured by ALTEA: Spectra and relative nuclear abundances in the polar,equatorial and SAA regions

We present here the energy spectra relative to different geomagnetic regions as measured by the ALTEA (Anomalous Long Term Effects on Astronauts) detector in the International Space Station – USLab from August 2006 to July 2007.     

Multimodal characteristics of a piezoelectric lead zirconate titanate element impacted with iron particles having velocities above 20 km/s

The responses of a piezoelectric lead zirconate titanate (PZT) element to hypervelocity collisions were experimentally studied. In this study, the particles of masses ranging from 0.3 to 10 fg were made to collide with PZT at velocities between 20 and 96 km/s. The amplitude and the corresponding rise time of the single-pulse output signals that were produced in the piezoelectric PZT element were measured to determine the possible collision states. The results revealed an apparently multimodal output; three classes were assumed to be involved in the pulse formation mechanism. The amplitude and rise time were sensitive to the collision velocity. The multimodal behavior implied that the PZT-based cosmic dust detectors should be calibrated according to the class they belong to.     

某型飞机座舱温度调节系统检测仪的研制

为满足某型飞机座舱温度调节系统原位检测的需要,结合外场实际．研制了该型飞机的座舱温度调节系统检测仪。经用户使用证明．该检测仪能够满足飞机的检测需要。     

火星大气来流模拟装置CFD仿真与试验

根据我国火星着陆巡视器工作过程,其着陆发动机需要在相对火星大气高速迎风运动中可靠点火。由于巡视器着陆时发动机喷管出口气流与火星稀薄气流方向相反,目前无法通过理论计算准确获得着陆过程的动态流场对发动机起动过程的影响量值。为验证火星着陆环境下发动机点火的适应性,需要建立发动机的火星大气来流试验环境模拟条件。为模拟发动机在火星大气条件下的相对运动,在真空舱内发动机保持固定,前端设置环形来流形成装置,该装置在发动机喷管周围形成一定速度的逆向来流包络。采用数值模拟技术结合试验验证方法,在火星着陆器巡视器主发动机性能考核试验中,针对来流的形成装置开展了设计研究工作。来流模拟试验测试数据表明:在确保贮箱供应压力稳定的条件下,来流模拟系统能够形成100~200 m/s速度的稳定来流,发动机在来流下能稳定启动工作,真空舱压力满足试验要求。     

大型空间模拟器总体检漏技术

论述了大型空间环境模拟器的总体检漏技术,针对大型模拟器的特点,从设计、加工到安装调试等过程介绍了检漏方法的选择,并着重介绍了氦质谱检漏法可检灵敏度的分析,对大型模拟器的检漏方案进行了全过程的设计.     

星载电场探测仪的传感器空间布局研究

电场探测仪是卫星进行高精度电场探测的关键载荷,其传感器的空间布局对探测精度影响很大。文章对传感器空间布局的影响因素和分析方法进行了研究,并以轨道高度500km的太阳同步轨道卫星为例,结合卫星的实际任务运行,对虚假光电场控制、电场探测仪传感器的几何布局构型、传感器与卫星的相互遮挡和干涉关系进行了分析,并最终优化确定了传感器的空间布局。研究结果表明,优化的传感器空间布局可以在设计阶段就针对多种误差,有效地提高其探测精度。     

吸枪检漏法的原理研究

航天器的单点漏率测试通常采用氦质谱吸枪检漏法,因此,该方法的合理性研究具有重要的工程意义。文章首次建立了吸枪检漏法的数学模型,并通过理论分析得到了被检件的漏率与检漏仪显示值的定量关系。其次,通过大量试验间接证明了该模型的正确性。最后,证明了氦质谱吸枪比对法的理论合理性。结果表明:用吸枪检漏法测单点的漏率具有较好的合理性,所得结论可以为吸枪法检漏的具体实施提供重要的理论依据。     

ABORT-like detector to combat active deceptive jamming in a network of LFM radars

This paper studies an electronic counter-counter measures (ECCM) scheme combating against deceptive electronic counter measure (ECM) techniques.An adaptive detector exploiting generalized likelihood ratio test (GRLT) criterion is applied to detect the presence of deceptive jamming in fractional Fourier transform (FrFT) domain.First,the generating mechanism of spurious frequencies is analyzed based on the Volterra serial.The proposed nonlinear distortion model based on power amplifier behavior is robust in distortion analysis when the memory effect is considered.Second,a modified adaptive beamformer orthogonal rejection test (ABORT) like detector in closed form is built.The proposed detector can discriminate the echo and deceptive jamming adaptively by exploiting primary data and secondary data.This ECCM scheme is capable of guaranteeing the performance without the restriction of orthogonality,which is essential for the ABORT detectors.The expansion to radar network is discussed as a special case at the final part of this paper.Numerical simulations demonstrate the effectiveness of the proposed method.