双通偏振干涉滤光片的研究

研究了等厚度双通偏振干涉滤光片，在此基础上提出了新型双通偏振干涉滤光片，并分析了单通、双通以及新型双通偏振干涉滤光片的光谱特性。结果表明，新型双通偏振干涉滤光片不仅具有更好的光谱特性，而且能进一步减少延迟片数目，具有非常重要的实用价值，可望在基于硅片的液晶投影仪分/合色系统中得到广泛应用。     

TFT-LCD投影显示中的彩色偏振分色系统

针对TFTLCD液晶投影显示系统中彩色偏振分色器件,从设计和制备上分析了多种S和P偏振器件并给出了设计结果,通过优化设计可以减小分色滤光片透射带内的波纹,探讨了制备过程并给出了测量结果,制备的器件及系统应用于液晶投影显示中,获得了良好的性能.     

双光束磁光存贮中信号读出的偏振态分析

利用琼斯矩阵分析了双光束磁光存贮中信号读出系统偏振态的传输情况，推导了读出信号的表达式，分析了偏振分束镜与光盘盘基的相位延迟对读出信号的影响。     

多量子位Heisenberg XX链中的杂质纠缠

通过分析系统的杂质位与其余部分间的纠缠N_1-A以及单个正常位与其余部分间的纠缠N_L-A研究了匀强磁场作用下含杂质Heisenberg XX链的纠缠特性.研究表明三量子位时纠缠存在的临界温度依赖于杂质参数J₁和匀强磁场B.研究发现,当量子位L为奇数时,纠缠N_1-A随量子位的增加而增大,而L为偶数时则相反,并且量子位L为偶数时的纠缠大于量子位L为奇数时的纠缠;对N_L-A, 量子位L为奇数时,纠缠随杂质参数J₁的变化与L=3类似,而L为偶数时纠缠随杂质参数|J₁|的增加而增加.     

磁性隧道结中的量子相干输运研究

采用散射矩阵的方法研究了铁磁/绝缘层/半导体/绝缘层/铁磁(FM/I/SM/I/FM)磁性双隧道结的量子相干输运特性.研究发现当隧穿电子平均自由程(l_p)和中间层半导体厚度(L)可比拟时双结隧道磁阻(TMR)将随L的变化产生量子振荡，当l_p远大于L时振荡拐点处出现cut-off波矢，分析表明cut-off波矢主要是来自于隧道结两边的铁磁和半导体层隧穿电子动量波矢的高度不匹配性，随着L相似文献   

ZnO压敏陶瓷缺陷结构表征及冲击老化机理研究

对多元ZnO压敏陶瓷电阻片进行了多达14000次的大电流冲击老化试验, 通过显微结构、电气性能及介电特性的测量对其缺陷结构进行了表征, 并研究了缺陷结构与大电流冲击老化之间的关系. 试验表明多次大电流冲击老化导致试样的电气性能明显下降, 发现ZnO压敏陶瓷的几何效应不仅受控于晶粒还与晶界密切相关. 另外, 通过介电谱分析观察到ZnO压敏陶瓷存在四种缺陷弛豫过程, 低温-60 ℃下的两个缺陷弛豫峰激活能约为0.24 eV和0.35 eV, 认为它们分别对应着本征的锌填隙缺陷L(Zn_i^··)和氧空位缺陷L(V_O^·)并且不受冲击老化的影响. 高温80℃以上两个松弛峰的活化能约为0.71 eV和0.84 eV, 认为它们分别对应着非本征的晶间相电子陷阱L(ingr)和晶界处界面态陷阱L(gb). 发现大电流冲击后, 仅界面态陷阱激活能从0.84 eV降低到0.76 eV, 认为界面态陷阱主要控制着ZnO压敏陶瓷的电气性能和稳定性.     

γ-LiAlO2上a面ZnO薄膜的光谱特性研究

利用激光脉冲沉积(PLD)技术在(302)γ-LiAlO₂衬底上成功生长了非极性的a面(1120)ZnO薄膜，光致发光谱(PL)带边发射峰半峰宽仅为115meV.研究了非极性ZnO薄膜光谱特性的面内各向异性，发现随着入射光偏振方向改变，在偏振透射光谱上，吸收边移动了20meV，这与A、B激子和C激子的能量差一致；而在拉曼光谱上，激发光偏振方向的改变导致E₂模式的强度发生明显改变.     

用CARS技术确定拉曼退偏比的一种数据处理新方法

Yuika等人利用偏振CARS技术可以准确地确定分子的拉曼退偏比.其方法是，首先对不同检偏角_d所对应CARS谱峰的频率分布进行数学模拟，然后由所得系数随检偏角φ_d的变化求得使CARS信号中共振项消失的偏振角φ^０_d，最后由消失条件ρ＝-1/(tanθtanφ⁰_d)求出退偏比ρ，θ为产生CARS光的Pump光与Stokes光偏振方向的夹角.本文提出的数据处理方法，即交点法.同Yuika等人处理数据的方法相比，交点法毋需关于谱峰频率分布的知识，做法也更为简便.     

任意夹角的双色偏振激光作用下孤立阿秒脉冲的产生

本文选取脉宽为12 fs波长为2000 nm和800 nm的两束线性偏振激光, 适当调节两束激光的偏振方向的夹角θ, 发现当θ=π/2时, 高次谐波谱的第二级平台出现了“漏斗形”凹槽.当θ为π/6时, 得到了290 eV的超宽连续谱的高次谐波发射, 利用小波变换合理的解释了高次谐波形状及截止位置. 在该段连续谱上任意截取70 eV宽度的频率, 都可以得到脉宽约为60 as的孤立阿秒脉冲. 适当减小截取范围可以得到线性偏振的脉宽94 as的孤立阿秒脉冲. 这为实验中产生能灵活调节的孤立阿秒脉冲提供了一种方案.     

二元衍射光栅式偏光器件的设计

本文利用双折射晶体刻划成的二元衍射光栅的衍射偏振特性,设计了偏光器件(可分别对o光或e光起偏);偏光分束器件(包括非对称及对称偏振分束两类),并对有关参数对设计的影响进行了讨论.     

Interaction induced delocalization of two particles: large system size calculations and dependence on interaction strength

The localization length L₂ of two interacting particles in a one-dimensional disordered system is studied for very large system sizes by an efficient and accurate variant of the Green function method. The numerical results (at the band center) can be well described by the functional form L ₂ =L ₁ [0.5+c(U) L ₁ ] where L₁ is the one-particle localization length and the coefficient depends on the strength U of the on-site Hubbard interaction. The Breit-Wigner width or equivalently the (inverse) life time of non-interacting pair states is analytically calculated for small disorder and taking into account the energy dependence of the one-particle localization length. This provides a consistent theoretical explanation of the numerically found U-dependence of c(U). Received 16 September 1998     

AlGaN/GaN场板结构高电子迁移率晶体管的场板尺寸优化分析

对不同场板尺寸的AlGaN/GaN 场板结构高电子迁移率晶体管进行了研究,建立简化模型分析场板长度对沟道电场分布的影响.结果表明,调整钝化层厚度和场板长度都可以调制沟道电场的分布形状,当场板长度较小时,随着长度的增大器件击穿电压随之增加,而当长度增大到一定程度后器件击穿电压不再增加.通过优化场板长度,器件击穿电压提高了64%,且实验结果与模拟结果相符. 关键词： AlGaN/GaN 击穿电压 场板长度     

苯甲酸-镝-钇配合物的发光

合成了苯甲酸-镝-钇固体配合物并研究了它们的光致发光性质.实验结果表明,当苯甲酸镝中部分Dy3+离子被Y3+离子取代时,可以便配合物中Dy3+离子的发光增强.     

半柔性网络剪切模量的计算

采用ANSYS软件计算了二维半柔性网络的剪切变形,得到了纤维绕交点可自由旋转和不可自由旋转的剪切模量G_fix和G_free,分析了纤维交点数、长度、纤维力学参数对半柔性网络剪切模量的影响,对比发现G_fix/G_free存在极小值,G_fix/G_free≈1.05. 关键词： 半柔性网络 复杂网络动力学 软凝聚态物质 多尺度     

Two interacting particles in a disordered chain III: Dynamical aspects of the interplay disorder-interaction

The interplay between the quantum interferences responsible for one particle localization over a length L₁, and the partial dephasing induced by a local interaction of strength U with another particle leading to partial delocalization over a length L ₂ > L ₁ , is illustrated by a study of the motion of two particles put close to each other at the initial time. Localization is reached in two steps. First, before the time t₁ necessary to propagate over L₁, the interaction slows down the ballistic motion. On the contrary, after t₁ the interaction favors a very slow delocalization, characterized by a spreading of the center of mass, until L₂ is reached. This slow motion is related to the absence of quantum chaos in this one dimensional model, the interaction being only able to induce weaker chaos with critical spectral statistics. Under appropriate initial conditions, the motion remains invariant under the duality transformation mapping the behavior at small U onto the behavior at large U. Received 24 August 1998     

Formation and Development of Phase Morphology and Structure on Polystyrene Blends. I. Study of Phase Behavior and Structure Character of Polystyrene/Poly (cis‐butadiene) Rubber Immiscible System During Melt Blending by Scanning Electron Microscopy

Abstract

Polystyrene/poly(cis‐butadiene) rubber blends were prepared by melt blending. The morphology development of the blend system was examined by intermittent extraction of material and scanning electron microscopy. The mixing process of the immiscible system was described through the characteristic length L and the average characteristic length L _m. The distribution of L was shown to be consonant with a log‐normal distribution. The mixing system was demonstrated to possess self‐similarity in a certain range of time and space, as shown through a scale function. Furthermore, the fractal dimension D at different times was calculated and shown to be a parameter that can be used to describe the dynamic process of the melt blending.     

On the environmental decoherence and spin interference in mesoscopic loop structures

Mechanisms of ‘environmental decoherence’ such as surface scattering, Elliot–Yafet process and precession mechanisms, as well as their influence on the spin phase relaxation are considered and compared. It is shown that the ‘spin ballistic’ regime is possible, when the phase relaxation length for the spin part of the wave function (L^(s)) is much greater than the phase relaxation length for the ‘orbital part’ (L^(e)). In the presence of an additional magnetic field, the spin part of the electron's wave function (WF) acquires a phase shift due to additional spin precession about that field. If the structure length L is chosen to be L^(s)>L>L^(e), it is possible to ‘wash out’ the quantum interference related to the phase coherence of the ‘orbital part’ of the WF, retaining at the same time that related to the phase coherence of the spin part and, hence, to reveal corresponding conductance oscillations.     

Bias‐driven super‐insulating state in prismane single‐molecule contacts

Quantum transport in a single‐molecule contact made of a prismane cluster C₈ attached to quasi‐one‐dimensional gold (100) electrodes is calculated using the ab initio methodology based on the density‐functional theory and the nonequilibrium Green's functions formalism. Varying the junction length L we calculate the length dependence of the zero‐bias conductance G (L) and, for a set of the interelectrode distances, the current–voltage (I –V) characteristics. It is shown that the G (L) dependence is strongly nonmonotonic with a sharp dip at some value of L. With increase in L, the I –V curves change their shape from monotonic curves to curves with a negative differential resistance area and, for a larger L, the junction exhibits the super‐insulating state, i.e., within some applied bias voltage range the current through the junctions is about two orders of magnitude less than the current outside this bias range. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The quantum harmonic oscillator on a circle and a deformed Heisenberg algebra

We show that the Heisenberg-type algebra describing the first levels of the quantum harmonic oscillator on a circle of large length L is a deformed Heisenberg algebra. The successive energy levels of this quantum harmonic oscillator on a circle of large length L are interpreted, similarly to the standard quantum one-dimensional harmonic oscillator on an infinite line, as being obtained by the creation of a quantum particle of frequency w at very high energies. Received: 29 March 2001 / Revised version: 17 July 2001 / Published online: 31 August 2001