用计入相干势近似修正的LCAO方法计算合金的能隙变化

以虚晶近似(VCA)为零级近似,计入相干势近似(CPA)修正,使用由原子轨道的Bloch和为基的紧束缚方法(LCAO)计算了A_xB_(1-x)型合金GaAs_xP_(1-x)的能隙E_g随浓度x的变化.所得结果与实验符合很好.该方法也可用于其他任意的A_xB_(1-x)型合金,并能计算能带结构及态密度等别的量.     

Ga_xIn_(1-x)P_yAs_(1-y)及Ga_xIn_(1-x)P_yAs_(1-y)/InP(110)异质结界面的电子能带结构

以半经验的紧束缚方法,采用非线性修正的虚晶近似,计算了与InP晶格匹配的Ga_xIn_(1-x)P_yAs_(1-y)的体电子能带结构以及 Ga_xIn_(1-x)P_yAs_(1-y)/InP(110)异质结的界面电子能带结构.     

与InP晶格相匹配的Ga_xIn_(1-x)P_yAs_(1-y)半导体的光学常数计算

采用半经验的紧束缚方法计算了与InP晶格相匹配的Ga_xIn_(1-x)P_yAs_(1-y)半导体的电子联合状态密度及介电常数虚部,并根据Kramers-Kronig关系式求得了光透明区的折射率常数.     

亚稳半导体(GaAs)_(1-x)(Ge_2)_x的能带结构

根据Kim及Stern由计算机模拟方法计算得到的亚稳半导体(GaAs)_(1-x)(Ge_2)_x在(100)面层状生长条件下的序参数s与组分x间的关系,并考虑到在任何组分的情况下,亚稳半导体始终保持短程有序,采用经验的紧束缚方法以及推广的虚晶近似,计算了亚稳半导体(GaAs)_(1-x)(Ge_2)_x的直接能隙与组分x间的变化关系.并把计算结果与实验及以前的理论模型进行了比较与讨论.     

工程数学

0174.6,0174.1 95050027虚阶变型B.获诊l函数的计算/范国新,杨弃疾(清华大学电子工程系)11电子学报一1995,23(6)一58~62. 给出了虚阶变型Bessel函数及其导数的计算公式和计算方法.数值计算结果表明,计算精度可达到10位以上有效数字.表3参15(文) 利用布尔函数的特征集合对布尔函数的线性结构进行了刻划,给出了寻找布尔函数的线性结构的一种方法.引人了布尔函数的r型线性结构的概念,并对其进行了研究‘参2(文)0177.6 95050028电力系统故障信号的小波分析和处理方法研究/刘劲,孙扬声,陈德树哗中理工大学)/l华中理工大学学报一1995,23(5)一84~5…     

(GaAs)_(1-x)Ge_(2x)半导体合金材料的电子结构及其基态性质

本文根据闪锌矿-金刚石结构的有序-无序相变模型,引入序参量M,在改进的虚晶格近似下,利用从第一性原理出发的自治LMTO-ASA方法,研究了(GaAs)_(1-x)Ge_(2x)半导体合金的电子结构和基态性质.计算结果与现有的非自治计算结果和实验结果进行了比较.计算表明,合金材料中轻、重空穴有效质量依赖于合金的有序度.计算也表明合金材料的晶格常数和体弹性模量将随组份x变化而呈现类似“V”形变化.这都说明,在有序和无序的组份区域,合金性质随组份的变化规律是不同的,应分区描述.     

一种降低CO-OFDM系统PAPR的PTS方法

为降低相干光正交频分复用(C0-0FDM)系统的峰均功率比(PAPR),对序列的实部和虚部分别独立应用部分传输序列(PTS)方法优化处理,并把迭代算法用于计算过程中,得到一种实部和虚部独立迭代优化的PTS方法.理论和仿真表明,该方法在有效减少计算量的同时又能获得较好的PAPR性能.     

流体静压力下窄禁带Hg_(1-x)Cd_xTe电学性质的研究

本工作在 0-15kb的流体静压力范围内及 196 K和283-383K的温度下,测量了n-Hg_(1-x)Cd_xTe(0.05≤x≤0.25)电子浓度及电阻率随压力的变化n(p)和ρ(p).由实验值n(p)计算了禁带宽度E_g和费米能级E_f随压力的变化,并同利用化学键的介电理论和虚晶近似计算得到的(dE_g)/dP(x)进行比较.再将上述结果E_g(P)和E_f(P)作为基本变量,考虑极性光学(P.O.)声子散射和带电中心散射,计算了本实验条件下n-Hg_xCdxTe的迁移率和电阻率随压力的相对变化曲线,并同实验结果加以比较.     

基于提前分配路径的低时延片上路由器结构

该文针对片上网络提出一种基于提前分配路径的低时延片上路由器结构(PAPR).新路由器采用提前路由计算和提前分配路径来缩短路由器流水线深度.提前路由计算为虚信道提前分配提供了可靠保障,即使在虚信道路径提前分配失败的情况下,也不影响分组在网络中的传输时延.该文提出基于缓存状态的仲裁算法BSTS(Buffer Status)综合考虑当前节点缓存信息和下游节点缓存信息,不但降低了分组等待时延,而且降低了缓存空闲的概率.仿真结果表明,新路由器能明显改善网络的时延和吞吐性能,相比采用滑动迭代轮询仲裁iSLIP(iterative Round-Robin Matching with SLIP(Serial Line Interface Protocal))算法的经典虚信道路由器,网络平均端到端时延降低了24.5％,吞吐率提高了27.5％;与采用轮询迭代RRM(Round-Robin Matching)算法的经典虚信道路由器相比,平均端到端时延降低了39.2％,吞吐率提高了47.2％.路由器硬件开销和平均功耗分别增加仅为8.9％,5.9％.     

单原子层应变超晶格(Si)_1/(Si_(1-x)Ge_x)_1(100)的电子结构

在计入应力的紧束缚框架之下计算了单原子层应变超晶格(Si)_1/(Si_1-xGo_x)_1的电子结构.对应于不同应变条件,得出能隙随组分的变化,并结合能带边不连续的变动加以考察.超晶格取Si(或Ge)晶格常数后能隙随组分的非单调变化源自合金受相同应力后能隙的类似特点.超晶格能带及态密度均呈现类Si的闪锌矿结构对称性.在虚晶近似得出的能隙和电子状态密度的基础上,利用相干势近似作了进一步的修正.     

InP与In_（1－x）Ga_xAs_yP_（1－y）／InP的电解液电调制反射

研究了ＩｎＰ样品和Ｉｎ１－ｘＧａｘＡｓｙＰ１－ｙ液相外延片在３００～８００ｎｍ范围内的电调制反射光谱。利用Ａｐｓｎｅｓ三点法计算了临界点能量、增宽因子和自旋轨道分裂值。通过实验曲线与理论公式的拟合，确定了临界点能维数及相位因子。并且间接提供了被测Ｉｎ１－ｘＧａｘＡｓｙＰ１－ｙ四元合金的组份值及其它临界点能量值Ｅ０和Ｅ２。     

Analysis of the high resolution spectrum of the fundamental bandsv 2 andv 5 of12CH3F and their interactions

Thev ₂(A₁) andv ⁵(E) fundamental vibration-rotation bands of¹²CH₃F have been recorded under high resolution (0.015 to 0.020 cm^?1) in the spectral range of 1460 cm^?1. About 1100 transitions have been assigned. The Coriolis interaction between v₂=1 and v₅=1, and the l(2,-1) interaction in v₅=1 have been rigorously treated. Sixteen molecular constants have been determined from a least squares analysis. They reproduce the observed data with an overall standard deviation of 0.0037 cm^?1.     

用共振多光子电离法研究Gd原子的高激发态

以Gd原子999cm~(-1)亚稳态为初始能级,用共振多光子电离(RMPI)方法研究了Gd原子在34463～35628cm~(-1)范围内的高激发态。实验共测得19个高激发能级。     

Far infrared spectrum of CD3OH methanol from 40–220 CM−1

The Fourier transform far-infrared (FTFIR) spectrum of CD₃OH has been obtained from 40–220 cm^?1 at a resolution of 0.002 cm^?1, and partially analyzed. Numerousb-type branches have been assigned in the spectrum, ranging over torsional states fromn=0 to 3. The branches have been fitted toJ(J+1) power-series energy expansions in order to obtainJ-independent branch origins. These in turn have been fitted to the torsion-rotation Hamiltonian, and improved molecular constants have been obtained for the ground vibrational state.     

高压IGBT的研制

介绍高压绝缘栅双极晶体管（ＩＧＢＴ）的终端和单元的设计与制造技术；实验验证了两种用于１０００～１２００ＶＩＧＢＴ的高压终端，研制的芯片获得了７．５Ａ，耐压１１５０Ｖ的实验结果。     

高压H_2气受激喇曼移频器的实验研究

本文报道RS-I型高效率高压H_2气受激喇曼移频器的实验装置和实验结果,观察到一至四阶斯托克斯线和一至八阶反斯托克斯线,总能量转换效率达56％,一阶斯托克斯能量转换效率达34％。     

Injection control of a multipass amplification of a dischargeexcited XeF (C→A) laser

The laser performance and kinetic properties of the broadband C→A transition of the XeF*-exciplex have been studied under discharge excitation. With a pulsed dye laser as the injection source, amplified output pulses with an energy of up to 4 mJ have been obtained in the wavelength range from 450 to 520 nm. Injection of a well-defined seed pulse in an unstable confocal cavity has been developed into a useful technique for identification of subtle kinetic details of the complicated lasing process in XeF*, such as the role of the competitive narrow-band B→X transition or the influence of the various buffer gases     

Torsion-rotation far-infrared spectrum of O-18 methanol

High-resolution Fourier transform spectra have been recorded from 15–470 cm^?1 for the far-infrared trosion-rotation band of O-18 methanol in the vibrational ground state. So far, 57 subbands have been assigned in the 15–220 cm^?1 region for a wide range of rotational and torsional states, and their J-independent origins have been determined to an estimated accuracy of ±0.01 cm^?1. The observed origins were found to deviate in many cases by several tenths of a cm^?1 from the values calculated with the previous molecular parameters. Together with 4 known microwave origins, the new data have been fitted to a model torsion-rotation Hamiltonian in order to refine the set ofb-type molecular constants for the ground state. With the new parameter set, the experimental subband origins are reproduced with an rms error of ±0.02 cm^?1, representing a substantial improvement over the earlier situation. The spectroscopic results have also been of great assistance with our assignments of optically-pumped FIR laser emission in CH₃ ¹⁸OH, in providing FIR data for checking the identification of the IR-pump/FIR-laser transition systems through combination loop relations.     

Substrate effects on performance of InP MOSFETs

InP MOSFET devices with a SiO2 dielectric layer have been fabricated on p-type and SI substrates. Surface mobilities in the range 250 to 750 cm2 V?1 s?1 have been routinely obtained from all substrates except those from one crystal of Fe-doped SI InP. Defect etching studies have revealed large prismatic dislocation loops in this crystal. A correlation between these observations is proposed.