具有Washer型输入线圈的超导量子干涉放大器的制备与表征

超导量子干涉仪(SQUID)放大器具有低输入阻抗、低噪声、低功耗等优点, 目前被广泛用于微弱信号的检测领域. 与其他工艺相比, Nb/Al-AlO_x/Nb结构的约瑟夫森结具有相对较高的转变温度(T_c)、高的磁通电压调制系数以及良好的热循环能力、较宽的临界电流范围, 因此是制备SQUID放大器的很好选择. 设计并制作了欠阻尼、过阻尼约瑟夫森结以及具有Washer型输入线圈的单SQUID放大器, 通过在He³制冷机3 K温区下对器件电流-电压特性进行测量, 得到良好的结I-V特性曲线、SQUID调制特性, 初步实现利用SQUID进行放大作用, 并计算了SQUID的电流分辨率. 此项工作对于超导转变边沿传感器读出电路的实现具有重要的意义.     

具有P型覆盖层新型超级结横向双扩散功率器件

为了设计功率集成电路所需要的低功耗横向双扩散金属氧化物半导体器件(lateral double-diffused MOSFET), 在已有的N型缓冲层超级结LDMOS(N-buffered-SJ-LDMOS)结构基础上, 提出了一种具有P型覆盖层新型超级结LDMOS结构(P-covered-SJ-LDMOS). 这种结构不但能够消除传统的N沟道SJ-LDMOS由于P型衬底产生的衬底辅助耗尽问题, 使得超级结层的N区和P区的电荷完全补偿, 而且还能利用覆盖层的电荷补偿作用, 提高N型缓冲层浓度, 从而降低了器件的比导通电阻. 利用三维仿真软件ISE分析表明, 在漂移区长度均为10 μm的情况下, P-covered-SJ-LDMOS的比导通电阻较一般SJ-LDMOS结构降低了59%左右, 较文献提出的N型缓冲层 SJ-LDMOS(N-buffered-SJ-LDMOS)结构降低了43%左右.     

Homogenization of the Signorini boundary‐value problem in a thick junction and boundary integral equations for the homogenized problem

We consider a mixed boundary‐value problem for the Poisson equation in a thick junction Ω_ε which is the union of a domain Ω₀ and a large number of ε—periodically situated thin cylinders. The non‐uniform Signorini conditions are given on the lateral surfaces of the cylinders. The asymptotic analysis of this problem is done as ε→0, i.e. when the number of the thin cylinders infinitely increases and their thickness tends to zero. We prove a convergence theorem and show that the non‐uniform Signorini boundary conditions are transformed in the limiting variational inequalities in the region that is filled up by the thin cylinders as ε→0. The convergence of the energy integrals is proved as well. The existence and uniqueness of the solution to this non‐standard limit problem is established. This solution can be constructed by using a penalty formulation and successive iteration. For some subclass, these problems can be reduced to an obstacle problem in Ω₀ and an appropriate postprocessing. The equations in Ω₀ finally are also treated with boundary integral equations. Copyright © 2010 John Wiley & Sons, Ltd.     

增溶性辅料泊洛沙姆188与胆酸聚集形态的介观模拟

为了建立符合中药特点的增溶性药用辅料的筛选与评价方法,本研究以清开灵注射液为研究载体,采用介观动力学方法(MesoDyn)研究其难溶活性成分胆酸与增溶性辅料泊洛沙姆188之间的相互作用,探讨了胆酸对泊洛沙姆188临界胶束浓度的影响及泊洛沙姆188浓度、模拟时间、温度对两者聚集体构型的影响,并采用实验方法验证了部分模拟结果,为中药注射剂增溶性辅料的科学应用提供一定基础.结果表明:在清开灵注射液中活性成分胆酸的存在下,泊洛沙姆188的临界胶束浓度范围为0.6%～0.7%,降低了泊洛沙姆188自身的临界胶束浓度,为使清开灵注射液中的胆酸(3%)全部增溶,泊洛沙姆188浓度应为1.7%.     

体外预应力加固的技术研究

通过ANSYS有限元模型, 以体外预应力筋为研究对象, 对体外预应力加固的关键技术 进行了研究, 得出体外预应力的作用位置, 尽可能拟合原结构的受力状况, 保证 加固工程的安全性; 体外预应力的补强力筋, 应采用等效面积的置换原则, 使施工的过程 趋于合理; 体外力筋的连接装置, 应该``适、薄、强'; 在加固工程中, 体外预应力筋 纵向交错布筋的设置, 能提升结构的整体延性.     

Soft X‐ray absorption spectroscopy and resonant inelastic X‐ray scattering spectroscopy below 100 eV: probing first‐row transition‐metal M‐edges in chemical complexes

X‐ray absorption and scattering spectroscopies involving the 3d transition‐metal K‐ and L‐edges have a long history in studying inorganic and bioinorganic molecules. However, there have been very few studies using the M‐edges, which are below 100 eV. Synchrotron‐based X‐ray sources can have higher energy resolution at M‐edges. M‐edge X‐ray absorption spectroscopy (XAS) and resonant inelastic X‐ray scattering (RIXS) could therefore provide complementary information to K‐ and L‐edge spectroscopies. In this study, M_2,3‐edge XAS on several Co, Ni and Cu complexes are measured and their spectral information, such as chemical shifts and covalency effects, are analyzed and discussed. In addition, M_2,3‐edge RIXS on NiO, NiF₂ and two other covalent complexes have been performed and different d–d transition patterns have been observed. Although still preliminary, this work on 3d metal complexes demonstrates the potential to use M‐edge XAS and RIXS on more complicated 3d metal complexes in the future. The potential for using high‐sensitivity and high‐resolution superconducting tunnel junction X‐ray detectors below 100 eV is also illustrated and discussed.     

第一性原理研究Hg2CuTi型Heusler合金Ti2FeB的磁性和半金属性

基于密度泛函理论的GGA计算,我们具体研究了Hg2 CuTi型Heusler合金Ti2 FeB的电子结构和磁性质,结果发现Ti2FeB合金在其费米面处存在100％的自旋极化,并在5.1～6.2(A)晶格范围内被保留.Ti2FeB具有大约0.5 eV的半金属带隙和1μB的原胞总磁矩,是一个稳定的半金属铁磁体.此外,我们的研究也表明RKKY型间接交换和d电子杂化在决定合金磁性质中起决定性作用.     

非晶硅碳薄膜发光二极管发光的热致猝灭

本文详细测试了用RF-PECVD法制备的非晶硅碳薄膜发光二极管的光强电流特性和温度对器件发光强度的影响.在直流电流驱动下,器件的发光在注入电流1A/cm2左右趋于饱和,而在低占空比的脉冲电流驱动下器件的发光直至注入电流20A/cm2仍随电流近似线性增长,但提高环境温度发光随之下降.结合对器件受热情况分析表明,热致猝灭而非场致猝灭导致了器件在大电流下的发光饱和,并简要提出了改进器件散热的措施.     

声表面波MIM隧道发光二极管

我们在研究MIM隧道发光结(金属-绝缘层-金属)的过程中,首次以表面声波代替表面随机粗糙度的作用,将MIM结制作在声表面波场中,结果使结的发光效率、发光强度、稳定性、均匀性都有改善.本文介绍了结的基本结构,基本工艺,阐明了结的发光机理,讨论了结的Ⅰ-Ⅴ特性曲线和光谱曲线,根据结具有显著的负阻现象,我们设计出了一种新型的开关器件.