应变Si n型金属氧化物半导体场效应晶体管电荷模型

基于应变Si/SiGe器件结构,本文建立了统一的应变Si NMOSFET电荷模型.该模型采用电荷作为状态变量,解决了电荷守恒问题.同时采用平滑函数,实现了应变Si NMOSFET端口电荷及其电容,从亚阈值区到强反型区以及从线性区到饱和区的平滑性,解决了模型的连续性问题.然后采用模拟硬件描述语言Verilog-A建立了电容模型.通过将模型的仿真结果和实验结果对比分析,验证了所建模型的有效性.该模型可为应变Si集成电路分析、设计提供重要参考.     

Derivation of microscopic unified Bohr–Mottelson rotational model

In a previous article, we derived a microscopic version of the phenomenological Bohr–Mottelson unified rotational model for rotation about a single axis. In this article, we generalize the derivation to that for rotation about all the three axes. As in the previous derivation, we apply the nuclear Hamiltonian directly to the rotational-model wavefunction instead of using the usual canonical transformation. In this way, we avoid using redundant coordinates or imposing any constraints on the rotationally-invariant rotational-model intrinsic wavefunction. We show that, in the transformed nuclear Schrödinger equation, the Coriolis coupling term vanishes exactly only for a choice of the rotational-model Euler angles that is consistent with angle-angular momentum commutation relation and rotational invariance of the intrinsic wavefunction. For this choice of the Euler angles, the kinematic moment-of-inertia tensor, collective-rotation velocity field, and flow vorticity have the rigid-flow characteristics. This quantum rigid flow reduces to irrotational free-vortex flow in the limit of a single particle. We derive a microscopic effective rotation-intrinsic unified Schrödinger equation for the states of a rotational band that reduces to the phenomenological, unified, tri-axial quantum rigid-rotor model in the limit that the off-diagonal elements of the kinematic inertia tensor operator can be neglected. The model derivation shows that a multi-fermion system with unpaired or paired (quasi) particles rotates rigidly and a single-particle system rotates irrotationally if the intrinsic system is rotationally invariant.     

Modeling of a triple reduced surface field silicon-on-insulator lateral double-diffused metal–oxide–semiconductor field-effect transistor with low on-state resistance

An analytical model for a novel triple reduced surface field(RESURF) silicon-on-insulator(SOI) lateral doublediffused metal–oxide–semiconductor(LDMOS) field effect transistor with n-type top(N-top) layer, which can obtain a low on-state resistance, is proposed in this paper. The analytical model for surface potential and electric field distributions of the novel triple RESURF SOI LDMOS is presented by solving the two-dimensional(2D) Poisson's equation, which can also be applied to single, double and conventional triple RESURF SOI structures. The breakdown voltage(BV) is formulized to quantify the breakdown characteristic. Besides, the optimal integrated charge of N-top layer(Q_(ntop)) is derived, which can give guidance for doping the N-top layer. All the analytical results are well verified by numerical simulation results,showing the validity of the presented model. Hence, the proposed model can be a good tool for the device designers to provide accurate first-order design schemes and physical insights into the high voltage triple RESURF SOI device with N-top layer.     

Derivation of microscopic uni-axial unified adiabatic Bohr–Mottelson rotational model

For a rotational motion about a single axis, we derive a microscopic, quantum version of the phenomenological Bohr–Mottelson unified adiabatic rotational model without using redundant coordinates, imposing constraints on the intrinsic state or the particle coordinates, or assuming explicitly a deformed intrinsic state. The model Schrödinger equation is derived from the direct action of the multi-particle Hamiltonian operator on the rotational-model wavefunction. We show that the Coriolis-coupling terms in the derived Schrödinger equation vanish exactly only for a choice of the Euler angle that is consistent with the rotational model requirement that the intrinsic wavefunction be invariant under rotation. For this angle, which also satisfies the conjugate commutation relation, the kinematic moment-of-inertia tensor, collective-rotation velocity field, and flow vorticity have the rigid-flow characteristics. Pairing interaction and fluctuations in the rigid-flow moment of inertia are shown to reduce the rigid-flow value of the kinematic moment of inertia in closer agreement with the experimental value. The derivation shows that a multi-fermion system with unpaired or paired (quasi) particles rotates nearly rigidly and a single-particle system rotates irrotationally if the intrinsic system is rotationally invariant, regardless of the value of the moment of inertia and the nature of the rotationally-invariant momentum-independent interaction.     

MOS结构电离辐射效应模型研究

基于氧化层空穴俘获和质子诱导界面陷阱电荷形成物理机制的分析,分别建立了MOS结构电离辐射诱导氧化层陷阱电荷密度、界面陷阱电荷密度与辐射剂量相关性的物理模型.由模型可以得到,在低剂量辐照条件下辐射诱导产生的两种陷阱电荷密度与辐射剂量成线性关系,在中到高辐射剂量下诱导陷阱电荷密度趋于饱和,模型可以很好地描述这两种陷阱电荷与辐射剂量之间的关系.最后讨论了低剂量辐照下,两种辐射诱导陷阱电荷密度之间的关系,认为低辐射剂量下两者存在线性关系,并用实验验证了理论模型的正确性.该模型为辐射环境下MOS器件辐射损伤提供了更 关键词： MOS结构 辐射 界面陷阱 氧化层陷阱     

Theory of laterally nonuniform MOS transistor under weak inversion: A technique for determination of interface parameters

The well-known model of current-voltage (I-V) characteristics of a MOS transistor (MOST) in weak inversion [1] was modified with regard to lateral nonuniformity of the semiconductor surface potential. A simple technique for determining the fluctuation parameter and the spectral density of interface states from drain-current (output) and drain-gate (transfer) single-threshold I-V characteristics is developed. Combined with measurements of the MOST threshold voltage, it makes possible the calculation of the effective oxide charge. The technique is fairly accurate and is useful for IC process control.     

基于Thomas-Fermi-Kirzhnits模型的物态方程研究

本文针对丝阵Z箍缩等高能量密度物理实验的数值模拟研究, 建立了一种适用温度、密度范围宽的三项式半经验物态方程. 三项式半经验物态方程包括零温自由能项, 电子热贡献项和离子热贡献项. 零温自由能项采用多项式拟合的方法确定. 多项式系数通过多项式计算的结果与高压缩比区域和压缩比为1时零温Thomas-Fermi-Kirzhnits模型计算的结果对应相等得到. 离子对物态方程的热贡献采用一种准谐振模型, 此谐振模型可以描述离子在固态相中的行为, 并且在高温度、低密度区域趋近于理想气体物态方程. 电子对物态方程的热贡献采用含温Thomas-Fermi-Kirzhnits模型计算. 利用所建立的三项式半经验物态方程计算了铝的等温压缩曲线, 并与实验数据做了对比. 给出了很宽温度、密度范围内铝的压强, 其数据与相应的SESAME数据库数据做了对比.     

一种红外光谱免疫计算的矿物组分定量提取方法

近红外/短波红外光谱的矿物组分快速鉴定技术可以大大提高野外矿产勘查、遥感矿物填图、岩芯矿物组分分析等工作的效率,成为目前高光谱技术研究的热点之一。文章给出了一个基于光谱相似度评价约束的联合目标岩石样品光谱和矿物光谱端元库进行矿物组分光谱反演的统一模型,然后以矿物光谱线性混合模型和光谱夹角相似度评价为例,建立了一个具体的组分反演模型;针对模型求解过程中的组合优化问题,提出了一种人工免疫克隆选择计算的矿物组分光谱(ICSFSLIM)识别方法;利用在中国新疆包古图地区选取的22个野外岩石样品的实测近红外/短波红外光谱进行了矿物组分提取试验,以样品薄片鉴定结果为准,将ICSFSLIM识别结果与组合特征光谱线性反演模型(CFSLIM)识别结果进行了定量的对比分析。结果表明：ICSFSLIM比CFSLIM的识别正确率提高了2.26%,有效率提高了18.6%,并且具有更高的识别稳定性。     

蛋白质构型变化的二维广义郎之万方程描述

采用二维广义郎之万方程描述蛋白质构型的随机变化,并与电子输运过程的原子密度填充模型相协调. 假设通过键和通过空间的两类电子输运路径分别受到高斯分数噪声和高斯白噪声的影响. 推导了电子转移给体-受体距离涨落和荧光寿命涨落自相关函数的一般表达式. 采用数值拉普拉斯反变换计算了蛋白质构型涨落动力学,并详尽讨论了长时间和短时间行为的渐近解析. 最后,明确了基于二维广义郎之万方程的蛋白质构型描述与一维描述之间的关系.     

DSM-LPDF两相湍流模型及旋流两相流动的模拟

本文由流体－颗粒速度的拉氏联合概率密度函数（ＰＤＦ）输运方程出发,用Ｓｉｍｏｎｉｎ建议的Ｌａｎｇｅｖｉｎ模型封闭颗粒所遇到流体瞬时速度的条件期望项,并用Ｍｏｎｔｅ Ｃａｒｌｏ方法直接求解 ＰＤＦ输运方程,将其和求解流体雷诺应力方程模型的有限差分方法结合,建立了雷诺应力－拉氏ＰＤＦ（ＤＳＭ－ＬＰＤＦ,简称ＤＬ）两相湍流模型．用此模型模拟了旋流数为０．４７的突扩旋流气粒两相流动,并与文献中ＰＤＰＡ实验和用类似于单相流动湍流模型封闭方法的时平均统一二阶矩（ＵＳＭ）模型的预报进行了对比．     

Temporal Behavior of Rabi Oscillation in Nanomechanical QED System with a Nonlinear Resonator

In nanomechanical QED system,consisting of a charge qubit and a nanomechanical resonator with intrinsic nonlinearity,we study the temporal behavior of Rabi oscillation in the nonlinear Jaynes-Cummings model.Using microscopic master equation approach,we solve time evolution of the density operator describing this model.Also,the probability of excited state of charge qubit is calculated.These analytic calculations show how nonlinearity parameter and decay rates of two different excited states of the qubit-resonator system affect time-oscillating and decaying of Rabi oscillation.     

A generalized Hartree-Fock-Bogoliubov approach for the description of band structures in nuclei: (II). The generalized Hartree-Fock-Bogoliubov theory in the intrinsic frame of reference

The problem of the occupation number calculation for the generalized Hartree-Fock-Bogoliubov (GHFB) approach is solved by introducing an intrinsic frame of reference, where the generalized density matrix and the average field Hamiltonian becomes diagonal with respect to the nulcear spin I. Using variational methods a dynamical equation is obtained, which determines the intrinsic density matrix. Its eigenvalues are defined by means of additional kinematical conditions following from the Pauli principle. A special symmetry of the intrinsic average field Hamiltonian allows us to divide the quasiparticle states in to two conjugated groups having positive quasiparticle energies and the corresponding negative quasiparticle energies, respectively. A generalized Coriolis interaction and new self-consistency conditions are derived. The relation of the present model to the self-consistent cranking model is discussed. As a numerical example the equilibrium deformation for a system of nucléons moving in a spherical oscillator potential and interacting via simple quadrupole forces is calculated.     

The density wave in a new anisotropic continuum model

In this paper the new continuum traffic flow model proposed by Jiang et al is developed based on an improved car-following model, in which the speed gradient term replaces the density gradient term in the equation of motion. It overcomes the wrong-way travel which exists in many high-order continuum models. Based on the continuum version of car-following model, the condition for stable traffic flow is derived. Nonlinear analysis shows that the density fluctuation in traffic flow induces a variety of density waves. Near the onset of instability, a small disturbance could lead to solitons determined by the Korteweg-de-Vries （KdV） equation, and the soliton solution is derived.     

The density wave in a new anisotropic continuum model

In this paper the new continuum traffic flow model proposed by Jiang {\it et al is developed based on an improved car-following model, in which the speed gradient term replaces the density gradient term in the equation of motion. It overcomes the wrong-way travel which exists in many high-order continuum models. Based on the continuum version of car-following model, the condition for stable traffic flow is derived. Nonlinear analysis shows that the density fluctuation in traffic flow induces a variety of density waves. Near the onset of instability, a small disturbance could lead to solitons determined by the Korteweg--de-Vries (KdV) equation, and the soliton solution is derived.     

Raman自由电子激光的半经典理论

采用Ｔｈｏｍａｓ-Ｆｅｒｍｉ近似势，将多电子系统简化为单电子问题，并用微扰论求解了Ｋｌｅｉｎ-Ｇｏｒｄｏｎ方程．由电子的零级波函数求得了电荷密度和电流密度的零级表达式．通过适当简化Ｋｌｅｉｎ-Ｇｏｒｄｏｎ方程，用分离变量和ＷＫＢ近似，求得了电子波函数及相应的电荷密度与电流密度的表达式 关键词：     

非球对称电离层掩星数据反演

电离层掩星数据的传统反演方法是电离层球对称假设下的Abel变换反演方法,但是实际的电离层电子密度分布不是球对称的,电离层的非球对称分布给电离层电子密度反演带来误差.发展了一种新的非球对称电离层掩星反演方法,利用国际参考电离层模型提供的三维电离层电子密度分布先验信息来修正掩星总电子含量 ,再通过球对称假设下的Abel变换反演出电离层电子密度.利用新方法反演了星座气象、电离层和气候观察系统掩星实测数据,并将得到的反演结果与电离层探测器资料进行了比较.结果表明,新方法能够较好地反演出电离层电子密度. 关键词： 电离层掩星 电子密度 国际参考电离层模型     

Coherent control of the spin current through a quantum dot

Within the weak-coupling regime the spin current through a quantum dot system is calculated using a quantum master equation approach which includes a sum over Matsubara terms. To be able to efficiently calculate, also at low temperatures, the time evolution of the reduced density matrix a high-temperature approximation was derived which proves to be rather accurate in comparison to the exact results. In the present model it is assumed that the energy levels of the dot are split by a constant magnetic field. An additional external (laser) field is used to control the currents of the two spin polarizations. This is either done using the phenomenon of coherent destruction of tunneling or optimal control theory. Scenarios are studied in which the spin current is reversed while the charge current is kept constant.     

热质的运动与传递-热波

根据爱因斯坦狭义相对论,热量具有其对应的相对论质量,并且引入了描述热质(热量)运动的连续方程、动量方程.本文根据热质(热量)运动控制方程组,导出了热质(热量)的波动方程,证明了热量具有波动的传递方式,当热质动能与热质的耗散在同一量级时,得到了有限的热波传播速度.分析了热波产生的物理机制.基于热质理论的热波模型与CV模型进行了比较,指出了CV模型在物理上的缺陷.最后对一维热波的传播过程进行了数值模拟,给出了超快速导热过程的物理图像.     

Space charge solution of Rittner photoconductor equation for a HgCdTe detector

The steady-state charge continuity equations are linearized to derive a space charge field that accompanies the ambipolar diffusion and drift described by the Rittner equation. The space charge field is evaluated for a typical 14.2 μm cutoff wavelength HgCdTe detector operating at 85 K. It is found that the space charge density is ∼10⁻⁵ times the hole and electron population density generated by photon flux. This corroborates that Rittner's equation gives an accurate solution for the hole and electron densities. But, at relatively high photon flux levels that are found in some Geostationary Operational Environment Satellite instrument channels, the small average space charge field can have a noticable effect on the linearity of detector response. Divergence of electric field terms in the continuity equations, which are absent from the Rittner equation, can also contribute a non-linearity to detector response.