实时光电混合SA■数据处理器

设计了一种光电混合综合孔径雷达(SAR)数据处理器,它利用声光器件(AOD)作为实时输入电-光转换器,利用光学系统实现SAR数据距离维的聚焦,利用CCD完成SAR数据在方位维的压缩并同时输出处理后的SAR图像。给出了实验室实时完成SAR数据距离维聚焦的有关图片。     

全国影片判读和数据处理讨论会在南京召开

中国光学学会高速摄影与光子学委员会于一九八四年十一月二十一日至二十四日在南京召开了全国影片判读和数据处理讨论会。参加会议的代表来自全国四十二个单位共计六十七人。会议上宣读了学术论文二十二篇,进行了有关判读仪的专题讨论会,并参观了华东工学院的有关实验室。 这次讨论会是继去年12月在上海举行的“全国高速摄影应用技术学术交流会“后,专业委员会搞的又一次学术活动。从这次会议的论文和发言,可以高兴地看到:影片判读     

1/N展开技术的一些应用

引入高阶修正项的1/N展开技术所推导出的sdIBMl的能谱和E2跃迁概率的理论公式,应用于铀区的一些核,与实验符合令人满意.结果表明,高阶修正项对于重现E2跃迁十分重要.     

实验测定弹性模量时的数据处理方法

测量金属材料的弹性模量是材料力学实验教学的重要内容之一,多数参考文献采用平均应变增量法来处理实验数据。本文针对平均应变增量法和几种常用平均法在计算弹性模量时的特征进行分析,指出了平均应变增量法在测量低碳钢弹性模量过程的主要缺陷,明确了最小二乘法拟合在处理弹性模量时的作用和意义。     

A model to explain the angular distribution of J/Ψ and Ψ(2S) decay into■ and ■

BESⅢ data show a particular angular distribution for the decay of J/Ψ and Ψ(2 S) mesons into ■ andΣ~0Σ~0 hyperons: the angular distribution of the decay Ψ(2 S) →Σ~0Σ~0 exhibits an opposite trend with respect to the other three channels: J/Ψ→■, J/Ψ→Σ~0Σ~0 and Ψ(2 S) →■. We define a model to explain the origin of this phenomenon.     

N/P沟道MOSFET1/f噪声的统一模型

对n／p两种沟道类型、不同沟道尺寸MOSFET的1／f噪声特性进行了实验和理论研究.实验结 果表明，虽然nMOSFET的1／f噪声幅值比pMOSFET大一个数量级，但是其噪声幅值均表现出和 有效栅压的平方成反比、和漏压的平方成正比、和沟道面积成反比的规律.基于该实验结果 ，认为MOSFET的1/f噪声产生机理为位于半导体_氧化物界面附近几个纳米范围内的氧化层陷 阱通过俘获和发射过程与沟道交换载流子，在引起载流子数涨落的同时也通过库仑散射导致 沟道载流子迁移率的涨落.在这两种涨落机理的基础上，引入了氧化层陷阱的分布特征及其 与沟道交换载流子的隧穿和热激活两种方式，建立了MOSFET l／f噪声的统一模型.实验结果 和本文模型符合良好. 关键词： 1/f噪声 MOSFET 氧化层陷阱 涨落     

Study of ■ decay parameter in J/ψ→Λ■ decay

The helicity amplitudes for J/ψ→Λ■ and the relevant background decays are presented for measuring the ■ decay parameter α (■→π ) in J/ψ→Λ■. The Monte Carlo (MC) simulations based on the helicity amplitudes information are carried out. The likelihood fit method to determine the ■ decay parameter is presented. Based on the MC generated sample, the sensitivity of the measurement for α has been estimated, which shows that the J/ψ→Λ■ channel can be used to measure the ■ decay parameter α (■→π ) well.     

Universal Teichmüller Space and DiffS 1/S 1

We point out that the coset space DiffS ¹/S ¹ is a dense complex submanifold of the Universal Teichmüller SpaceS of compact Riemann spaces of genus g1. A holomorphic map ofS into the inifinite dimensional Segal diskD ₁ is constructed. This is the Universal analogue of the map of Teichmüller spaces into the Siegel disk provided by the period matrix. The Kähler potential for the general homogenous metric on DiffS ¹/S ¹ is computed explicitly using the map intoD ₁. Some applications to string theory are discussed.This work was supported in part by the U.S. Department of Energy Contract No. DE-AC02-76ER13065     

D-wave excited ■ tetraquark states with JPC=1++ and 1+-

We study the mass spectra of D-wave excited cscs tetraquark states with J^PC=1⁺⁺ and 1^+- in both symmetric ■ and antisymmetric ■ color configurations using the QCD sum rule method.We construct the D-wave diquark-antidiquark type of cscs tetraquark interpolating currents in various excitation structures with(L_λ,L_ρ(l_p1,l_ρ2))=(2,0{0,0)),(1,1{1,0)),(1,1{0,1)),(0,2{1,1)),(0,2{2,0}),(0,2{0,2}).Our results support the interpret...     

S=1/2体系的EPR波谱模拟

用一个以Fortran语言编制的S=1/2体系的EPR模拟谱程序.并引入了弛豫项,图谱线型得到了改善,使模拟谱与实验谱更为接近;对超超精细分裂的考虑,使该程序可适合于复杂图谱的模拟;求积分方法的近似处理,缩短了模拟谱的耗时,使复杂图谱的模拟在微机上成为现实.     

通过J/Ψ→N(N-)M衰变研究N*时的核子极点效应

研究了J／Ψ→pp^-π衰变过程中核子极点图的贡献，特别是由离壳效应带来的贡献．发现衰变宽度对形状因子是敏感的．在通过用J／Ψ→pp^-π衰变研究N^*时，核子极点图作为背景道的贡献是非常重要的；在通过J／Ψ→pp^-η和pp^-η研究N^*时，核子极点图的贡献可忽略不计；在通过J／Ψ→pp^-ω研究N^*时，核子极点图有明显的贡献．     

GaAs1-xPx:N束缚激子的压力行为

本文研究了77K温度下GaAs_0.15P_0.85:N样品的静压光致发光。在P>10kbar时,可清楚地观察到NN₁的发光。同时,观察到压力下N_x带发光猝灭及谱带窄化现象。结果表明,压力效应明显地加强了N_x→NN₁的热助能量转移过程。对N_x能级和NN₁能级的压力行为进行了分析和拟合计算,得到相应能级的压力系数及波函数中各能谷的有关参数。 关键词：     

高线性度Al_xGa_(1-x)N/Al_yGa_(1-y)N/GaN高电子迁移率晶体管优化设计

对新型复合沟道AlxGa1-xN/AlyGa1-yN/GaN高电子迁移率晶体管(HEMT)进行了优化设计.从半导体能带理论与量子阱理论出发,自洽求解了器件层结构参数对器件导带能级以及二维电子气(2DEG)中载流子浓度和横向电场的影响.用TCAD软件仿真得到了器件的层结构参数对器件性能的影响.结合理论分析和仿真结果确定了器件的最佳外延层结构Al0.31Ga0.69N/Al0.04Ga0.96N/GaNHEMT.对栅长1μm,栅宽100μm的器件仿真表明,器件的最大跨导为300mS/mm,且在栅极电压-2—1V的宽范围内跨导变化很小,表明器件具有较好的线性度;器件的最大电流密度为1300mA/mm,特征频率为11.5GHz,最大振荡频率为32.5GHz.     

Doppler-free two-color spectroscopy of the 62 S 1/2–82 S 1/2 cesium transition using semiconductor diode lasers

We report an experimental investigation of the 6S–8S transition of cesium atoms by using Doppler-free two-color spectroscopy. We consider the case in which one of the laser frequencies is nearly resonant with the 6S _1/2–6P _3/2 transition while a second one is swept around the 6P _3/2–8S _1/2 transition. The lineshapes of two-photon absorption spectra are analyzed taking into account the effects of saturation and collisions. Both counterpropagating and copropagating laser-beam schemes are studied. Although for the linewidths are broader copropagating beams, such a scheme has proved advantageous to fully resolve the hyperfine structure of the final state 8S _1/2 and, hence, to measure the dipole magnetic constantA of this state.     

Classical equationsdN i /dr=1/2iε ijk [N j,N k ]

We study the first order system of equationsdN _i /dr=1/2i _ijk [N _j ,N _k ], where theN _i are classical, non-abelian gauge-Higgs fields with spherical symmetry. Exact solutions are constructed.Supported by the Hellenic National Research Foundation     

High-Reflectivity A1GaN/A1N Distributed Bragg Reflector in Ultraviolet Region

Thirty-pair Alo.3 Gao.T N/A1N distributed Bragg reflectors centred at 32Ohm are designed and grown on sapphire substrates by metalorganic chemical vapour deposition. No cracks are observed in the main area of the 2-inch wafer except for about 4 mm margin under an optical microscope. Regular stack of alternating layers is shown by scanning electron microscopy. Clear two-dimensional growth steps and very low surface roughness are shown by atomic force microscopy （AFM）. Well-defined periodicity is shown by high resolution x-ray diffraction. High refiectivity of 93% at 313nm with a bandwidth of 13nm is obtained.     

TheCP N−1 1/N-action by inverse scattering transformation in angular momentum

The effective action which generates 1/N expansion of theCP _N–1 model in two dimensions is studied here by inverse-problem methods. The action contains a functional determinant, in which auxiliary scalar and vector fields are assumed to have a spherical symmetry. This leads to the introduction, as an associated linear problem, of a radial Schrödinger equation with two potentialsv and , and a potential-dependent centrifugal term {(–r)²/r ²–1/4r ²}. The full inverse scattering formalism is developed here for this diffusion problem. It is formulated in terms of two-component Jost solutions, and leads to a matricial Gel'fand-Levitan-Marchenko equation. The scattering data associated to the potentials by this IST are then used to obtain a closed local form for the whole effective action. This is indeed possible for theCP _N–1 model, owing to the classical integrability. Moreover it is found that no spherically symmetric instanton exists in this case. However the absence of supplementary informations on the 1/N series, due to the non-integrability at quantum level, does not allow safe quantitative conclusions on the general behaviour of the 1/N series at large orders.Laboratoire associé au CNRS UA 280