三线阵CCD立体测绘相机的集成装调

考虑几何精度对三线阵CCD立体测绘相机测绘精度的影响,研究了测绘相机组合体的装调方法以建立和保证相机的空间几何关系。首先,介绍了测绘相机组合体的结构和坐标系的定义;其次,提出了各基准立方镜和相机的装调要求;最后,确定了多相机集成装调流程,重点介绍了测绘相机的装调步骤。装调结果表明：各相机的光学传递函数〉0.2,畸变〈0.03%,测绘相机的空间几何关系满足要求,提出的集成装调技术有效地保证了测绘相机的空间几何关系。     

星载TDICCD界面颤动的动力学模型及共振点扫描研究

简要分析了高分辨率星载遥感TDICCD相机的成像原理,研究了基于混合界面颤动的星载遥感TDICCD相机动力学分析模型.结果表明:星载遥感TDICCD相机对地观测时,载体部件的运动使相机产生振动响应,该响应会对成像质量有影响;对星载TDICCD相机进行了共振点扫描试验,试验测量了多点的加速度信号,并用信号分析仪进行了数据处理,获得了星载遥感TDICCD相机共振点扫描结果.这些动态特性结果为星载遥感TDICCD相机的防振、隔振设计提供了参考.     

精密角度基准下的多相机定位系统高精度标定

在视觉定位测量领域中的大尺寸测量、运动追踪、三维重建、视觉定位中,针对多相机定位系统中相机之间无公共视场或公共视场较小时系统标定困难、方法繁琐、精度低等问题,提出了一种基于精密二轴转台的多相机定位系统一体化标定方法。利用二轴转台提供角度基准,当转台一次转过所有相机视场时,各个相机依次拍摄标定图片,求解出各个相机内参以及各相机到转台的外参,利用转台坐标系中转计算相机之间的外参。整个标定过程由程序控制,实现了多相机系统采图标定的集成化、自动化,降低了标定工作量。分析了多相机定位系统的标定原理,并进行了实验验证。两相机内参重投影误差在0.17 pixel以内,系统定位精度在1 mm以内。结果表明,所提方法切实可行,精度较高,可操作性强,可应用于各种无公共视场或公共视场较小的多相机定位系统标定过程。     

超高速相机中的转像机构

转镜式超高速相机中增配了别汉棱镜转像机构后,对光学系统像差计算结果表明：相机的成像质量不受影响,甚至略有改善。鉴于转像机构在相机使用中带来的种种方便,提出了把棱镜转像机构作为相机固定组成部分的建议。特别是当高速分幅相机中配置棱镜转像机构后,可以充分利用相机的最高空间分辨方向,从而成倍地提高相机的时间分辨本领。     

Silex-I飞秒激光装置X射线探测系统时间特性北大核心CSCD

在Silex-Ⅰ飞秒激光装置上,利用32fs、800nm的激光辐照平面金靶,产生小于1ps的X射线脉冲,作为δ脉冲X射线源,研究XRD探测器的时间响应特性,并且探索X射线条纹相机时间分辨和分幅相机曝光时间的X射线标定方法。实验给出了XRD探测器的时间响应特性。解决了条纹相机和分幅相机触发晃动问题,给出了条纹相机时间分辨和分幅相机曝光时间的X射线标定方法,初步给出条纹相机时间分辨和分幅相机曝光时间。     

相机阵列在空间目标初轨确定中的应用

将由商业相机组成的相机阵列应用于空间目标的初轨确定。介绍了相机阵列的系统概况,结合相机阵列的技术特点,从空间目标探测能力、定位精度、初轨确定算法改进三方面分析了将相机阵列应用于空间目标初轨确定的可行性,提供了主要流程,进行了实验验证。实验结果初步展示了相机阵列系统在提高极限探测星等和初轨确定精度方面的能力。     

可见光条纹相机绝对灵敏度测量

为将可见光条纹相机应用于绝对测量领域,建立了可见光条纹相机绝对灵敏度测试方法。通过对条纹相机扫描成像过程的推导,定义了条纹相机的量子效率为某一波长光入射时,输出图像净计数与输入光子数之比。使用多模光纤分束器,实现了条纹相机输入光子数的定量,用经过标定的光电倍增管监测入射光子数,建立了条纹相机量子效率测试系统。利用该系统实际测试了某条纹相机的量子效率,结果为0.7 counts/photon。对测量环节的不确定度分析表明,测试结果不确定度在5%之内。这种方法在评估Z箍缩可见光条纹相机诊断系统的灵敏度中发挥了重要作用,也可应用于其他需要确定条纹相机可见光灵敏度的场合。     

航天遥感相机动态钳位设计

提出了航天遥感相机的动态钳位方法,该方法通过在相机的模拟前端对大气程辐射值进行减除,实现场景信息的充分量化.建立了航天遥感相机成像链路模型,分析了大气程辐射对图像灰阶范围的影响.研制了动态钳位相机,实现了在相机硬件电路中减除模拟信号.在外场对动态钳位相机进行了实验验证,实验中利用MODTRAN软件计算大气程辐射并转换为相机钳位值.实验结果表明:本文方法可使相机低端信息得到充分利用,图像灰阶范围能够提高62%;在航天遥感相机中设计动态钳位能够利用低端量化信息,用更多的量化位数来表示地物目标信息,并可提高辐射分辨率,保留更多图像的细节信息.     

一种光学遥感卫星多相机成像系统的高精度影像拼接方法EI北大核心CSCD

提出一种基于虚拟大相机的光学遥感卫星多相机系统成像数据的拼接方法,实现多相机影像的高精度拼接。该方法根据各单相机的几何成像模型,构建虚拟大相机的几何成像模型;利用坐标正算、反算过程对各单相机影像进行间接法几何纠正,得到虚拟大相机图像坐标系下的各虚拟单相机影像;将各虚拟单相机影像基于影像坐标信息拼接处理后得到最终的虚拟大相机影像。该方法利用虚拟大相机实现多相机影像的高质量拼接,为后期处理提供了与之相对应的高精度有理函数模型,可用于不同数量、不同分辨率的多相机系统实现全自动智能地面预处理。     

一种光学遥感卫星多相机成像系统的高精度影像拼接方法

提出一种基于虚拟大相机的光学遥感卫星多相机系统成像数据的拼接方法,实现多相机影像的高精度拼接。该方法根据各单相机的几何成像模型,构建虚拟大相机的几何成像模型;利用坐标正算、反算过程对各单相机影像进行间接法几何纠正,得到虚拟大相机图像坐标系下的各虚拟单相机影像;将各虚拟单相机影像基于影像坐标信息拼接处理后得到最终的虚拟大相机影像。该方法利用虚拟大相机实现多相机影像的高质量拼接,为后期处理提供了与之相对应的高精度有理函数模型,可用于不同数量、不同分辨率的多相机系统实现全自动智能地面预处理。     

不同土壤种植下四种柴胡种质药材中常量及微量元素含量的比较研究

采用ICP-AES/ICP-MS技术对7种土壤种植下的4种柴胡种质药材中21种常量及微量元素含量进行了分析测定。综合考虑种质和土壤对柴胡药材中常量和微量元素含量的影响,K,Ca,Mg,Na 4种常量元素含量受种质影响较大,Fe,Cu,Ni,Ti,Cr,V,Zr,Se,Sn,Cs,Cd,Hg,Pb等13种微量元素含量则受土壤影响较大;4种柴胡种质中,以甘肃种质的柴胡药材中常量和微量元素含量较高,中柴1号柴胡药材中常量和微量元素含量较低;在7种土壤种植下,以在北京市延庆县永宁镇盛世营村山地土壤上种植的柴胡药材中常量及微量元素含量较低,而在北京市怀柔区喇嘛沟门乡东岔村土壤上种植的柴胡药材中常量及微量元素含量较高。这些研究结果为了解各自药材中药效成分的含量及其疗效差异起着重要作用,也为选择种质和土壤及栽培出高产优质的柴胡提供重要依据。     

Laser absorption and fluorescence diagnostics of a plasma

Diagnostics of a near-surface laser plasma, the plasma of a strong-current pulse gaseous discharge in inert gases, nitrogen, and carbon dioxide under conditions of intense evaporation of the wall of the discharge chamber, the plasma of a discharge with a hollow cathode, and the active medium of an excimer laser was conducted by methods of intracavity laser spectroscopy and laser-induced fluorescence. The dynamic fields and absolute concentrations of atoms, ions, molecules and electrons, the plasma temperature, and the velocities of flows of particles were measured. The quantitative determination of the density of particles in the erosion laser flame prior to breakdown and the phenomena associated with the formation of molecules in the laser plasma received primary consideration. To whom correspondence should be addressd. Instite of Molecular and Atomic Physics of the Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 281–290, May–June, 1997.     

空间调制微型傅里叶变换红外光谱仪研究

针对目前环境、医疗、空间、气象、军事及安全等领域对傅里叶变换红外光谱仪微小型化、轻量化及固态化的迫切需求,提出并研究了一种以MOEMS多级微反射镜为核心器件的空间调制微型傅里叶变换红外光谱仪。在理论研究方面,建立了空间调制微型傅里叶变换红外光谱仪的物理模型,探究了该系统的光场分割与空间采样的光学原理;分析了多级微反射镜的衍射效应,提出了一种通过补边抑制衍射噪声抑制方法;进行了多级微反射镜采样误差的分析,并提出了基于最小二乘拟合的修正算法;通过对光源空间相干性、准直系统像差以及入射光场均匀性的分析,确定了光学系统的总体设计指标;通过对多级微反射镜基片加工精度、分束器材料色散特性和膜层透射效率等的计算分析,确定了干涉系统的设计方法与技术参数。在核心技术方面,提出了两个多级微反射镜的3种制作方法,分析了制作误差的来源及对系统性能的影响。通过工艺设计及实验条件探索,分别采用电铸法、真空镀膜法以及斜面倾角叠片法制作了两个多级微反射镜。在系统设计方面,进行了红外准直与缩束系统的光学设计,对整体光机系统进行了建模仿真,分析了杂散光噪声的来源。在图谱处理方面,利用过零采样方式,通过图像分割算法,获取了干涉图采样序列;通过对干涉图序列的插值、补零、延拓与卷积方法,完成了光谱相位误差的校正;通过离散傅里叶变换解调,实现了由干涉图像到信号光谱的数据反演。最后研究了系统光机整体的集成组装技术,并对原理样机进行了实验测试。本文研制的空间调制微型傅里叶变换红外光谱仪的特点在于:取消了动镜驱动机构与采样控制机构,具有微小型与轻量化的特点;干涉图的采样由多级微反射镜完成,其空间采样的方式增加了系统的稳定性与可靠性,实时采样的特点增加了系统的快速性与有效性;多级微反射镜阵列采用MOEMS工艺技术制作,增加了系统的采样精度。该光谱仪系统的结构及制作方法具有自主知识产权,并具有广阔的应用前景。     

Electromagnetic volume scattering in the half-space: a moment-method analysis without Sommerfeld integrals or their approximations

Traditionally, in moment-method analyses of electromagnetic scattering, the elements of the impedance matrix are calculated as convolutions of the basis elements with the appropriate dyadic Green's function. However, for scattering in the half-space, the vertical and azimuthal copolar terms of the Green's function require evaluation of Sommerfeld integrals which are computationally burdensome. In this paper, it is shown that, in populating the impedance matrix for the half-space problem, evaluation of Sommerfeld integrals is, in fact, not necessary. For monochromatic excitation, the plane-wave expansion of the scattered field constitutes a Fourier transform, in the horizontal plane, of a vector spectral function. This vector function results from the convolution, in the vertical dimension, of the respective angular spectra of the Green's function and the equivalent current. On application of the moment method, through the Weyl identity, the impedance-matrix elements corresponding to the singular terms of the Green's function are convolutions in the horizontal plane of spherical potentials, and Fourier transforms of scalar spectral functions. These scalar functions are derived from the basis elements and, with a judicious choice of basis, they are well behaved and of compact support, and consequently their Fourier transforms can be computed as FFTs.     

Phenomenon of gravitational repulsion in the general theory of relativity

Einstein's generalization of Newton's theory of gravitation in the general theory of relativity led not only to small quantitative differences between gravitational effects in the relativistic theory and the Newtonian theory, but also to essentially new phenomena and effects peculiar to the relativistic theory and absent in the Newtonian theory. This difference is so large that the gravitational interaction in Einstein's theory even altered the attraction-only property, characteristic of Newton's theory, the law of universal gravitation, and became both attractive and repulsive. It is notable that the nature of the repulsion in gravitational interaction already appears in the simplest case of a spherically symmetric isolated body. Einstein's equations admit for a spherical body a solution whose physical interpretation uniquely indicates the repulsive nature of a gravitational field inside the body, if the number of particles that make up the body is sufficiently large. The structure of such a body, density distribution of the number of particles, mass, and pressure, is determined in the equilibrium state by the pressure of the substance, the gravitational attraction of peripheral layers toward the center, and the gravitational repulsion of inner layers of matter away from the center. As a result of the gravitational repulsion of matter away from the center inside the body there appears a cavity, free of the matter making up the body and its electromagnetic radiation. If the body is cold, then the volume of the world tube of the cavity can differ from zero. In the opposite case, the world tube of the cavity reduces to the world line of the center, which is inaccessible to particles of matter and to electromagnetic radiation. Gravitational repulsion, on the other hand, is a result of the existence of a field singularity at the center of the body, whose world line is time-like.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 61–67, April, 1981.     

Effect of spraying power on the microstructure and mechanical properties of supersonic plasma-sprayed Ni-based alloy coatings

The aim of this paper was to investigate the microstructure and mechanical properties of the supersonic plasma-sprayed Ni-Cr-B-Si-C coatings prepared at different spraying powers. The microstructure, phase composition, porosity, Young's modulus, micro-hardness, and residual stresses of the coatings were investigated and determined. The variations of the porosity, Young's modulus and micro-hardness of the coatings were evaluated by using statistical method. Results showed that the variations of porosity, Young's modulus and micro-hardness of the coatings followed the Weibull distributions. With increasing the porosity, the micro-hardness and Young's modulus of the coating decreased. The mean value of the Young's modulus of the coating calculated from Weibull plot was almost proportional to the square root of the micro-hardness of the coating. With increasing the power, Young's modulus of the coating increased, which, in turn, resulted in the increment of the residual stress at the coating surface.     

X-ray photoelectronic spectroscopy of the processes of interaction between elements in contact layers on InP

Using the method of x-ray photoelectronic spectroscopy, we investigated of the interaction of gold-containing contact layers and indium phosphide in the process of thermal burning-in. We determined the dependence of the depth of the InP layer that had entered into interaction with the metal of the contact on the type of alloying admixture and the gold layer thickness. Institute of Electronics, National Academy of Sciences of Belarus, 22, Logoiskii Trakt, Minsk, 220090, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 144–147, January–February, 1999.     

基于计算机辅助的医学图像测量与控制方法研究

医学图像常规检查中,需要对目标图像进行测量以获取相关数据。测量主要集中在对距离,面积,角度以及周长等数据的获取。由于医学检测的严谨性,数据准确,方法简便是必不可少的要求。随着计算机技术的发展,其在医学中的应用也得到了广泛的推崇。计算机辅助的医学图像测量不但替代了传统的手工测量方式,也极大地提高了测量的精度与效率。分析医学图像测量算法,针对如何确定目标区域的问题设计了颜色填充的方法,可有效区分出目标区域图像。为了提高该算法的效率,进一步提出了其改进算法,降低了算法执行次数,提高了系统性能。     

Structure-preserving algorithms for the Duffing equation

In this paper, the dissipative and the forced terms of the Duffing equation are considered as the perturbations of nonlinear Hamiltonian equations and the perturbational effect is indicated by parameter ε. Firstly, based on the gradient- Hamiltonian decomposition theory of vector fields, by using splitting methods, this paper constructs structure-preserving algorithms （SPAs） for the Duffing equation. Then, according to the Liouville formula, it proves that the Jacobian matrix determinants of the SPAs are equal to that of the exact flow of the Duffing equation. However, considering the explicit Runge Kutta methods, this paper finds that there is an error term of order p＋l for the Jacobian matrix determinants. The volume evolution law of a given region in phase space is discussed for different algorithms, respectively. As a result, the sum of Lyapunov exponents is exactly invariable for the SPAs proposed in this paper. Finally, through numerical experiments, relative norm errors and absolute energy errors of phase trajectories of the SPAs and the Heun method （a second-order Runge-Kutta method） are compared. Computational results illustrate that the SPAs are evidently better than the Heun method when e is small or equal to zero.     

颗粒度对不同煤种可见光-近红外光谱的影响

煤炭是我国最主要的能源,在开采、运输、洗选加工、精煤储运等过程中都需要及时了解煤的成分、含量以及混矸程度,以便掌握和监控煤炭质量。目前,基于可见光-近红外反射光谱的煤炭原位测试技术已经成为一个研究热点。颗粒度是影响光谱特征的重要因素,开展颗粒度对不同煤种反射光谱特征的影响研究,对于深刻认识煤的光谱特征,进而提高煤光谱识别精度具有重要意义。为此,选取我国主要煤炭富集区（包括内蒙古乌海、新疆哈密、山西阳泉）的褐煤、烟煤、无烟煤为研究对象,利用SVC HR-1024光谱仪对不同颗粒度煤样的可见光-近红外光谱进行测试,分析了颗粒度对煤样光谱反射率的影响规律,以及颗粒度对于不同煤种光谱影响的差异。在此基础上,对实验现象背后的物理机理进行了分析讨论。研究表明,变质程度不同的煤反射光谱特征基本相似,即在可见光波段反射率较低且随波长增加出现缓慢下降趋势,在近红外波段快速上升。当煤样颗粒度>0.10 mm时,颗粒度大小对光谱特征的影响较小,煤样反射光谱特征随颗粒度变化规律不明显;当颗粒度<0.10 mm时,颗粒度对煤样的光谱影响增大,且影响主要体现在近红外波段的反射率光谱曲线的斜率大小,颗粒度越小,光谱反射率曲线斜率越大。0.10 mm颗粒度可作为颗粒度对煤的光谱特征影响的敏感界限。不同煤种可见光-近红外光谱曲线受颗粒度的影响程度不同,褐煤的影响最大,烟煤次之,无烟煤影响最小。实验表明,利用反射光谱进行煤质分析和煤种识别时需要考虑颗粒度的影响,同时,选择颗粒度小于0.10 mm的粉末状样品效果要好于大颗粒或块状样品。