机载卫星制导武器直接瞄准攻击研究

 介绍了卫星制导武器直接瞄准攻击方式在对地精确打击中占据的关键位置,阐述了卫星制导武器直接瞄准攻击方法的原理。由于卫星制导武器直接瞄准攻击对目标定位要求较高,采用常用定位手段已不能满足系统对目标定位的要求,分析了使用相对GPS制导成为卫星制导武器直接瞄准攻击的关键的原因。相对GPS制导误差主要包括采用载机和武器相对GPS定位误差以及传感器对目标的相对定位误差,分别对两者的定位精度进行了分析和推导。仿真结果表明：这两者的综合误差理论值小于7.5 m,满足卫星制导武器在直接瞄准攻击中对目标定位的需求。     

大功率LED脉冲位置调制解调设计

脉冲位置调制是室内可见光通信的主要调制方式之一,它具有功率利用率高,频带利用率好,抗干扰性强的特点.为实现室内大功率白光LED照明通信,在分析PPM的原理基础上提出了一种改进的调制方式,给出了这种PPM符号的结构,并设计了大功率LED的驱动电路.其主要特点是由单片机直接输出帧同步信号加PPM信号,不设置保护时隙,其利用...     

DFT Study on Some Properties of Polybrominated Phenoxathiin 10-Oxides

With the B3LYP calculation method of density functional theory(DFT)and the 6-31G* basis set,full optimization calculation was made for phenoxathiin10-oxide(PTO)and 135 polybromine phenoxathiin 10-oxides(PBPTOs)with the Gaussian 03 program and molar heat capacity in constant volume(CVθ)value of each molecule in the standard state was obtained.The relation between CVθ and the substitution position and number of bromine atom(NPBS)was studied,and the results indicated good correlation(R2 = 1.000)between CVθ and NPBS of PBPTO compounds.Based on the output file of Gaussian 03 program,molar heat capacity at constant pressure(Cp,m)of PBPTO compounds from 200 to 1,000 K was calculated with the statistical thermodynamics program,and the correlation equation between Cp,m and temperature(T,T-1 and T-2)was obtained with the least-squares method,and the correlation coefficient of the correlation equation(R2)was 1.000.In addition,based on the partition function of each molecule calculated by vibration analysis,the relative rate constant of formation of each molecule was calculated.     

Scanning X-ray interferometry and the silicon lattice parameter: towards relative uncertainty?

In order to reduce measurement uncertainty of the (220) lattice spacing of silicon to a few parts per 10⁹, a combined X-ray and optical interferometer capable of millimeter scans is being tested. A new series of measurements confirmed the value obtained with our previous set-up, and the bounds of measurement uncertainty were investigated. The article supplements the analysis of the error budget and provides a safer footing for the monocrystalline silicon lattice parameter value. Received 13 August 1998     

Capacitive position measurement for high-precision space inertial sensor

Low noise position measurement is fundamental for space inertial sensors, and at present the capacitive position sensor is widely employed for space inertial sensors. The design for the possible suppression of the front-end electric noises for a capacitive sensor is presented. A prototype capacitive sensor with 2×10⁻⁶pF/Hz1/2 at frequency above 0.04 Hz is achieved and further improvements are discussed.      

Two-dimensional position sensitive neutron detector

Pramana - A two-dimensional position sensitive neutron detector has been developed. The detector is a3He + Kr filled multiwire proportional counter with charge division position readout and has a...     

An eye behavior measuring device for VR system

This work presents an eye-tracking and pupil size-measuring device that interfaces with a computer for applications useful in psychometry, ophthalmology, physiology and virtual reality (VR) systems. This system utilizes a change-coupled device (CCD) camera, appropriate lenses, PC with frame grabber and a DSP unit with various types of VR equipment, i.e., HMD, simulator or LCD projection device. The digital signal processing unit is used to calculate the average brightness and contrast of the VR video image. A CCD camera with various attachments can be mounted on various VR systems to capture the human eye image for testing. An image capture card and a personal computer are used to analyze the test image. From the eye digital image, the computer obtains data on the pupil size and a trace of the tested eye. A pattern recognition computer program and five measurement parameters are used to distinguish the position of the pupil, calculate the pupil location coordinate and analyze the physical conditions of the user. These data can be plotted against the average brightness and contrast of the VR video image in real time. This information is shown on the screen of a personal computer and used for cross-link analysis. This eye-tracking interface can determine the position of a subject's pupil and map that position into a display point on a computer screen. The pupil size and location data versus the average brightness and contrast of a VR video image are computed in real time.     

The effect of head position on glottic closure in patients with unilateral vocal fold paralysis

The present study was designed to assess the effect of head position on glottic closure as reflected in airflow rates (open quotient and maximum flow declination rate), in patients with unilateral vocal fold paralysis. Ten patients, 2 males and 8 females ranging in age from 40 to 75, with a mean age of 57.3, served as subjects. Airflow measures were taken during sustained phonation of two vowels (/i/ and /a/) in 3 head positions (center, right, left). Vowels /i/ and /a/ were produced at subject's comfortable pitch and loudness, with random ordering of both vowel order and head orientation. Subjects were trained to focus eye gaze on right and left markers (70-degree angle) and a central marker at eye level directly in front of the subject. Theoretically, if turning the head during phonation alters the laryngeal anatomic relationship by bringing the vocal folds in closer proximity to one another, then airflow rate should lessen. Our results indicate that head position does not improve glottic closure in these patients, which is in contrast to previously published research.(1) Our results question the utility and underlying theoretical construct for the use of head turning as a therapeutic technique for improvement of voice in patients with unilateral vocal fold paralysis.     

应用振幅矢量法讨论夫琅和费单缝衍射光强分布

本文提供了夫琅和费单缝衍射（简称衍射，下同）光强计算公式，与一般文献中的理论公式相比，不但完全等效，而且计算简便精确，对衍射光强分布的实际应用及实验测量￣［３］具有一事实上的参考价值。     

植物研究用γ射线成像系统设计

为了利用正电子发射断层成像技术在植物生理功能研究中的优势,正在开发由两个探测器相向放置构成的γ射线成像系统.系统中采用的探测器是由10×10的氧正硅酸镥(LSO)晶体阵列与滨松R5900-C12耦合组成.单个LSO尺寸为1.8mm×1.8mm×10mm.根据PET应用的特点,测试了该探测器的性能.所有闪烁晶体的图像在位置图谱中清楚可见;511keV全能峰处的能量分辨率位于14.5%—22%之间;符合时间分辨率随着位置灵敏光电倍增管的供给电压的增加而得到改善.这些实验结果表明,该LSO探测器适于构造高分辨率的双探测器成像系统.