A cryogenic target within an electric field

A liquid hydrogen target is placed inside a streamer chamber which has an electric field equal to 20 kV cm^?1. A flask of the target is made from mylar. Its diameter is 35 mm, its length is 198 mm and its thickness is 100 microns. The target box is made from polystyrene foam. The diameter of the box is 59 mm and its thickness is 7 mm. A source of cold for the target is a cooling gas machine having a power of 100 W.     

Low-Contrast Thermal Resolution Test Targets: A New Approach

A new type of thermal resolution test target optimized to minimize the effects of lateral thermal gradients at low thermal contrast is described. This target consists of thin-film inconel heater strips over an etched silica substrate bonded to an aluminum heat sink. A simple, finite-difference model is used to study how variations in target construction and materials affect the generated thermal resolution test pattern. The construction, testing, and use of this type of target to extend the lower end of the contrast range of a conventional target are described.     

Beam-spot temperature monitoring on the production target at the BigRIPS separator

Since 2007, a water-cooled high-power rotating disk target has been in operation at the in-flight radioactive-isotope beam separator (BigRIPS), RIKEN. The target should withstand a goal beam intensity of 1 particle μA (pμA) ²³⁸U-beam at 350 AMeV with a spot size of 1 mm in diameter, resulting in a heat deposit of 22 kW in the target.A beam-spot temperature monitoring system using infrared devices in high-radiation environment was elaborately developed. The beam-spot temperature on a beryllium (Be) fixed target and on a rotating Be and tungsten (W) disk target was measured with the most intense beams presently available at our facility. The heat deposit achieved was 0.6 kW, that is 1/37 of the goal value. At the present beam intensity, the result supports our estimation that a water-cooled rotating disk target of 30 cm diameter can withstand an approximately tenfold beam intensity compared to a water-cooled fixed target.     

强激光热斑形成及其稳定性研究

在论述热点跟踪及其传热机理时将靶材的比热溶、热传导系、在激光的热藕合系数均考虑成温度和时间的函数，又考虑靶材在运动时将激光辐照物体时热点的建立及其稳定情况作一动态数值模拟，为热点跟踪作准备。     

汇率目标区及其在投机性攻击下的稳定性分析

本文介绍汇率目标区的基本模型.指出汇率目标区的设想及行动计划,对目标区的检验、修正和扩展进行分析,进一步研究汇率目标区在投机攻击下的不稳定性,并做简要评论.     

弱小目标跟踪算法性能评估的研究

本文提出了弱小目标检测和跟踪算法的性能评估框架,并针对弱小目标检测和跟踪的特点,从背景特性、目标特性和跟踪干扰特性等方面对弱小目标序列图像的仿真进行了分析.通过分析弱小目标跟踪中可能遇到的不同的目标情况和由此产生的正确跟踪轨迹、正常轨迹消失、错误跟踪轨迹、遗漏轨迹和虚假跟踪轨迹等目标跟踪状况,以弱小目标仿真模块提供的目标原始真值为基础,采用了有效跟踪评价和有效跟踪精度评价的方法对跟踪算法进行评估.试验表明,该方法能够有效地评估弱小目标跟踪算法.     

图象序列中检测运动小目标的递归算法

分析了一种基于卡尔曼滤波理论的时域递归低通滤波算法。这种算法根据运动小目标,背景干扰和噪声在图象序列中的差异,能够抑制背景,增强小目标并将其从相对静止的背景中有效地分离出来。在恒虚警概率条件下,该算法可以在低信噪比的情况下,减小背景干扰和随机噪声的影响,提高信噪比,选取适当的阈值,能够得到清晰的小目标轮廓,通过仿真验证了这种算法的有效性     

A blow-in type windowless gas target for astro-nuclear experiments

A blow-in type windowless gas target (BIGT) has been developed for nuclear experiments near stellar energy, especially for a ⁴He+¹²C→¹⁶O+γ experiment. The target has a multi-layer structure for differential pumping. Cooling of the target by liquid nitrogen was tried, and the target thickness was found to increase only 1.2 times under a constant gas flow rate. The present target thickness along a beam axis is 1.5 kPa×2.94 cm, which is about a half of our goal. A gas target having very thin windows was also developed using a 50 nm thick silicon nitride foil.     

Distortion tolerant image recognition receiver by use of a multiple-hypothesis method

A multiple-hypothesis method is used to detect a target or a reference signal in the presence of additive noise with unknown statistics. The receiver is designed to detect the target and to be tolerant of the variations in rotation and illumination of the target. A multiple-hypothesis test with unknown-noise parameters is used to locate the target position. The proposed method does not use any specific distortion-invariant-filtering technique, but it relies on a multiple-hypothesis approach. Maximum-likelihood estimates of the illumination constant and the unknown noise parameters are obtained. Computer simulations are presented to evaluate the performance of the receiver for various distorted noisy true-class targets with varying illumination and false-class objects.     

高靶材利用率的新型磁控溅射器

在现代大型薄膜连续生产线中 ,其生产效率主要受以下两因数的影响 :溅射器的沉积速率和靶材的使用周期。本实验研制了一种圆筒形靶材绕溅射器中心轴线匀速旋转 ,并且与溅射器之间用螺丝固定连接的新型磁控溅射器。论述了新型溅射器的结构与组成 ,并给出实验结果与结论。其具有靶材利用率高、使用周期长、换靶时间短等优点。同时在反应溅射时避免在靶面上的形成介质层 ,提高了溅射过程的稳定性。     

A fuzzy model of the penetration resistance of concrete targets

The penetration resistance of a concrete target varies greatly with the strike velocity of the projectile from low and intermediate impact velocities to high impact velocities. A fuzzy model of the penetration resistance of a concrete target is proposed to describe this characteristic. A complete analysis is conducted of the penetration process during which a rigid projectile penetrates a semi-infinite concrete target based on the proposed fuzzy model. Good agreement is observed between the experimental and predicted results based on the proposed fuzzy model.     

纯角度跟踪的球面坐标降维算法

从解决目标跟踪中的非线性问题入手,分析了不同的解决方法,并结合地面红外搜索跟踪（IRST）系统单独使用时的实际特点,提出了球面坐标降维模型,给出了相应的目标纯角度跟踪算法。目标状态方程和量测方程得到了简化。最后进行了目标跟踪的仿真试验,结果表明这种纯角度跟踪算法具有很好的性能。     

A generalized formula for the penetration depth of a deformable projectile

A simple analytical algebraic formula is developed for predicting the penetration depth of a deformable projectile into a semi-infinite target. This formula is a simplified version of more general equations that have been developed to predict the time-dependent penetration process in finite thickness targets. Specifically, the formula generalizes the classical hydrodynamic theory to include dependence on elastic properties of the target and on the yield strengths of both the target and the projectile. Moreover, the formula is limited to the case of long-rod penetration where both the projectile and the target experience significant plastic flow. The limiting values of the location of the elastic–plastic boundary in the target have been determined, and a single empirical constant has been introduced to characterize the transition between these limiting values. A value for this empirical constant has been determined which produces theoretical predictions that are in reasonable agreement with experimental data for moderate to high values of the impact velocity of steel and tungsten projectiles penetrating a steel target.     

经纬仪目标交汇测量及航迹曲线拟合

一台经纬仪只能测量目标的方位角和俯仰角，即只能测得目标的方向。为确定空间运动目标在某一瞬间的位置，采用两台（或多台）经纬仪合理布站进行交汇测量的方法，可得到目标点的坐标值，根据不同时刻的坐标值，用最小二乘法对目标航迹进行曲线拟合，从而可以外推预测目标下一时刻的位置、速度和加速度。     

基于多波束系统的水下目标近程回波亮点声图像

模拟多波束系统,仿真得到了水下目标的二维回波亮点声图像。先采用小分置角双基地目标回波特性计算的近场板块元方法,计算得到水下目标的传递函数。再根据多波束系统的理论,建立了水下目标回波亮点二维声图像的基本框架,实现了水下目标回波亮点二维声图像仿真。最后得到了水下目标不同方位角情况下近程二维回波亮点的声图像。     

机车全动态包络线测量中的目标点自动识别算法研究

针对机车动态限界图像中目标点自动识别的问题,提出一种基于双分辨力分析的目标点识别算法,解决了高分辨力图像对于多目标的搜索效率问题,并提出了一种自描述向量用于改进传统的RANSAC算法,以减少背景噪声的干扰,完成了不同限界图像目标点的单应矩阵的求解问题。最终实现高效且准确的目标点自动识别与匹配。     

无线电引信模拟打靶质量检测系统研究

研究建立了无线电引信模拟打靶质量检测系统.该系统在计算机上模拟引信实际打靶过程中目标、背景及各种干扰仿真信号,通过多功能信号存放仪实时作用于引信,从而实现弹目交会过程中目标及环境对引信的作用仿真.同时,系统能实时记录引信各级工作点的瞬态响应波形及引信炸高,从而实现对引信质量的静态检测,并可实现故障诊断.     

图像序列中运动弱小目标的检测

根据序列图像中运动弱小目标的相关性,提出一种弱小目标检测的方法。采用能量积累的方法,提高图像信噪比;采用自适应门限进行阈值分割,得到二值化的图像;利用聚类的方法去掉噪声点。实验结果表明,该方法能够有效地提取出低信噪比下序列图像中的弱小目标。     

Filter model for lightness and brightness on different backgrounds.

A filter model is proposed to account for the effects of background luminance on perceived brightness or lightness of a target area. Special attention is focused on a crispening effect describable as a local increase of the rate of change of brightness with target luminance, as target luminance passes through the level of background luminance. The model is based on the assumption of competition, in the form of mutual-shunting-feedback inhibition, between target and surround.     

A vibrating target assembly for intense ion beams

A high power vibrating target assembly was designed for work with well-collimated intense proton beams. The water-cooled target vibrates in two mutually perpendicular directions at different frequencies. It is shown that for many target materials power dissipation up to 0.5 kW/cm² can be tolerated over long time intervals.