3-三苯基锗基-1,1-二苯基-1-丁醇类化合物的拉曼光谱和红外光谱研究

我们合成３－三苯基锗基－１,１－二苯基－１－丙醇及同系物３－三苯基锗基－１,１－二苯基－１－丁醇;３－三苯基锗基－２－甲基－１,１－二苯基－１－丙醇,这些化合物都是有机锗类化合物,是具有抗肿瘤活性的化合物３－三苯基锗基－１－二苯基－１－丙醇的类似物,它们可能具有生物活性。我们测量了它们的拉曼光谱及红外光谱。经光谱分析,指认了主要波数所对应的分子振动。在这三种化合物中,Ｇｅ－Ｐｈ的伸缩振动出现在１０     

3-三苯基锗基-1,1-二苯基-1-丙烯及其同系物的拉曼光谱和红外光谱

我们合成了一类多苯基取代的烯丙基锗烷类化合物,并测量了这三种化合物的拉曼光谱和红外光谱。经光谱分析,指认了主要波数所对应的分子振动。在这三种化合物的拉曼光谱中,Ge-Ph均在1000cm-1附近出现非常强的振动峰;烯丙基中的C=C键在1615 cm-1和1595 cm-1附近出现强的振动峰;在1585 cm-1附近出现芳香环的多重振动峰;在3050 cm-1(m)1、025 cm-1(m)、615 cm-1(m)附近出现芳香环的C-H伸缩振动,C-H面内弯曲振动和C-H面外弯曲振动峰;与饱和碳原子相连接的Ge-C振动峰分别出现在595 cm-1、592 cm-1和597 cm-1。在红外光谱中,这类化合物的Ge-C振动和饱和Ge-C振动较为明显,分别出现在1090 cm-1(s)附近和625 cm-1~577 cm-1(w)之间。     

高压处理对Bi1Sr1Ca1Cu2Oy超导电性的影响

本文在高T_c超导体Bi_1Sr_1Ca_1Cu_2O_y常压制备的基础上,研究了热压烧结和冷压处理对其形成、结构及超导电性的影响,并与常压结果进行了比较。结果表明,高压可以使样品的合成时间缩短,合成温度降低。但同时它也抑制了晶格参数较大的相(高T_c相)的形成,使小晶格参数的杂相含量增多。对于提高样品的超导电性而言,1.5 GPa是一个较好的压力点。     

Sinh-Gordon Matter Field and a Solvable Model in Two-Dimensional Gravity

The two-dimensional gravity model with a coupling constant k = 4 and a vanishing cosmological constant coupled to a sinh-Gordon matter field is investigated. We find that the classical equations of motion are exactly solvable, and analytically obtain the static solutions of induced metric and scalar curvature. These solutions have some new features and may be used to describe the naked singularities at the horizons.     

Comparative study of (1 0 0) and (1 1 1)B InGaAs single quantum well laser diodes

In this work, a series of identical In_xGa_1−xAs/Al_yGa_1−yAs single quantum well laser diodes, grown on (1 0 0) and (1 1 1)B GaAs substrates, have been thoroughly studied. For all samples, clear evidence of reduced threshold current densities in the (1 1 1)B substrate has been observed in electroluminescence spectra at 17 and 300 K. Modelling of the devices, based on a self-consistent solution of Schrödinger–Poisson's equations, was utilised in order to reproduce the experimental results. The model incorporates strain and piezoelectric effects on the quantum well states, free carrier screening, overlap integral computation, and optical gain calculation. The underlying mechanism, that explains the threshold reduction observed in the (1 1 1)B laser diodes, is discussed based on the results of the modelling.     

热声制冷的实验研究

自行研制了热声驱动脉管制冷机实验台,着重研究了加热温度、平均工作压力、小孔开度、工质各类等因素对脉管制冷机性能的影响。初步实验表明,以氮、氦及氦和氩混合物（氦占94％）作工质,分别获得了234.5K、179K及165K的无负荷制冷温度,此外,本文还指出了进一步改进方向,具有一定参考价值。     

The Unitary Operator Corresponding to the General Two-Mode Coordinate-Momentum Mixed Transformation

We discuss the unitary operator corresponding to the general two-mode coordinate-momentum mixed transformation(q2,p2)→(Aq1 Bq2,Cq1 Dp2),where A,B,C and Dare arbitrary real numbers,Suitably selecting the parameters A,B,Cand D,we obtain a new two-mode bosonic realization of the SU(1,1) Lie algebra.We also study the squeezing effects of the squeezed vacuum associated with the new two-mode bosonic realization of the SU(1,1) Lie algebra.The results show that the new squeezed vacuum does not possess second-order squeezing,but exhibits higher-order squeezing.     

Spontaneous U（1） Symmetry Breaking in Coupled Bose System

Adding a U(1) symmetry breaking term V^1/2 a(λ₁a₀+λ*₁a^†₀)+V^1/2(λ₂b₀+λ^*₂b^†₀) to Bogoliubov's truncated Hamiltonian H_B for a weakly interacting coupled Bose system, by using the mean-field approximation rather than the c-number approximation, we find that, via a Feshbach resonance at zero temperature, the states of the coupled Bose system are generalized SU(1,1) × SU(1,1) coherent states. The Bose-Einsteincondensation occurs in response to the spontaneous U(1) symmetry breaking.     

4,5-二氮杂芴-9-酮2-萘甲酰腙(HL)及其配合物PbL2的NMR研究

本文报道了4,5-二氮杂芴-9-酮2-萘甲酰腙(HL)及其配合物PbL₂的合成及其¹H和¹H-¹H COSYNMR表征.在PbL₂中配体以烯醇式配位;由于受到亚胺氮孤对电子的屏蔽,二氮杂芴环上的质子具有不等价性。     

用荧光方法检测HIV-1整合酶的体外活性

HIV-1整合酶是抗艾滋病药物研究的一个重要靶点。整合酶催化两步反应使病毒cDNA整合到宿主细胞基因组中, 该反应过程可以在体外利用重组蛋白和DNA底物实现。本研究构建了HIV-1整合酶表达载体, 在大肠杆菌中诱导表达, 亲和纯化得到重组整合酶蛋白, 利用荧光染料标记DNA底物分子和荧光标记抗体, 通过荧光信号检测整合酶对DNA的切割和连接两步反应, 达到检测整合酶体外活性的效果。该方法具有灵敏度高、特异性好等优点, 便于开展以整合酶为靶点的药物筛选等工作。     

Raman Spectrum Study on the Doping Effect in LiNbO3: MgO Crystals

Raman spectra of LiNbO₃: MgO crystals have been obtained and compared with Raman spectra of pure LiNbO₃ crystals. For both of the two kinds of Raman active modes (4A₁+9E), no changes of the numbers, frequency-shifts, and relative intensities of the Raman spectral lines are found. However, it is observed that some modes coupled to each other at room temperature. The observed modes coupling phenomena, disappeared at low temperature. It is shown from these results that the Raman spectral lines of A₁ (TO) and E (TO) vibrational modes are mainly determined by the (NbO₆) oxygen octahedra characteristic groups of LiNbO₃ crystals.     

The transport properties of Dirac fermions in chemical vapour-deposited single-layer graphene

Abstract

The electronic transport properties of Dirac fermions in chemical vapour-deposited single-layer epitaxial graphene on anSiO₂/Si substrate have been investigated using the Shubnikov–de Haas (SdH) oscillations technique. The magnetoresistance measurements were performed in the temperature range between 1.8 and 43 K and at magnetic fields up to 11 T. The 2D carrier density and the Fermi energy have been determined from the period of the SdH oscillations. In addition, the in-plane effective mass as well as the quantum lifetime of 2D carriers have been calculated from the temperature and magnetic field dependences of the SdH oscillation amplitude. The sheet carrier density (1.42 × 10¹³ cm^?2 at 1.8 K), obtained from the low-field Hall Effect measurements, is larger than that of 2D carrier density (8.13 × 10¹² cm^?2). On the other hand, the magnetoresistance includes strong magnetic field dependent positive, non-oscillatory background magnetoresistance. The strong magnetic field dependence of the magnetoresistance and the differences between sheet carrier and 2D carrier density can be attributed to the 3D carriers between the graphene sheet and the SiO₂/Si substrate.     

Core-level photoelectron study of indium chains on Si(1 1 1) at 10 K

High-resolution core-level data from the prototypical In/Si(1 1 1) system have been acquired at 10 K. An asymmetric tail in the In 4d spectra reveals a metallic character of the low temperature Si(1 1 1)8 × 2 phase confined to the inner indium rows. The decoupling of the one-dimensional inner indium chains from any metallic environment at ∼10 K suggests a possible Luttinger liquid behavior. At room temperature essentially a broadening of the spectral features is noticed, which appears compatible with a fluctuation scenario.     

Radiative heat transfer in axisymmetric domains of complex shape with Fresnel boundaries

A detailed study of the peculiarities of the radiative heat transfer (RHT) in axisymmetric domains bounded with Fresnel surfaces is undertaken. The analytical (exact) solutions of the RHT problem in conical and cylindrical domains with refractive index more than unity were obtained for a variety of absorption coefficient and geometrical parameters of the domains. It is shown that due to Fresnel reflections the net radiative flux strongly varies over the base of cone and cylinder. The difference in RHT processes for the cases of constant reflectivity of the boundaries and that calculated by Fresnel formula is demonstrated. The influence of specular reflection at the crystal side surface on the shape of the solid/liquid interface in growing bismuth germanate crystals is shown.     

用2D NMR研究前胡香豆素F的结构

应用¹H-¹H COSY,¹³C-¹H COSY及COLOC并结合其它波谱技术对从中药白花前胡(Peucedanum praeruptorum Dunn)根中分得的一种新化合物前胡香豆素F进行了深入研究,其化学结构确定为3'-异戍烯酰氧基花椒内酯,为吡喃环上3'位烯醇羟基的氧原子和异戍烯酰基形成的烯醇酯.这种新颖结构在自然界中比较少见。     

Variable Separation Solutions in (1+1)-Dimensional and (3+1)-Dimensional Systems via Entangled Mapping Approach

In this paper, the entangled mapping approach (EMA) is applied to obtain variable separation solutions of (1 1)-dimensional and (3 1)-dimensional systems. By analysis, we firstly find that there also exists a common formula to describe suitable physical fields or potentials for these (1 1)-dimensional models such as coupled integrable dispersionless (CID) and shallow water wave equations. Moreover, we find that the variable separation solution of the (3 1)-dimensional Burgers system satisfies the completely same form as the universal quantity U1 in (2 1 )-dimensional systems. The only difference is that the function q is a solution of a constraint equation and p is an arbitrary function of three independent variables.     

Eu3+、Tb3+与1-乙酰乙酰吲哚、1,10-邻菲啰啉二元、三元体系在溶液中荧光光谱研究

观察了以不同比例溶解在乙醇中的Eu3+、Tb3+、1-乙酰乙酰吲哚(HL)和1,10-邻菲啉(Phen)的荧光光谱.结果表明HL能有效地把吸收的能量传递给Tb3+,而不能有效地传递给Eu3+.讨论了HL和Phen对Eu3+、Tb3+的配位作用及其对Eu3+或Tb3+所组成的三元体系中敏化发光性能的影响.     

LD侧面抽运Nd∶YAG多波长激光器

利用单根Nd∶YAG晶体棒,实现1064nm和1319nm双波长基频光振荡及其倍频光532nm、660nm激光的输出.采用LD侧面抽运单根Nd∶YAG晶体棒实现1064nm和1319nm基频光振荡,在此基础上使用非线性频率变换技术获得532nm和660nm倍频光的输出.结果表明:1064nm和1319nm基频激光同时输出时功率分别为30.5W和8.78W,单独输出时功率分别为35.6W和11.2W;在声光调Q频率分别为10.5kHz和20.5kHz时,获得了功率分别为5.34W和1.353W的532nm激光和660nm激光两路同时运转输出、功率分别为6.72W和1.902W各路单独输出,两种情况下倍频转换效率均为17.5%和15.4%,不稳定度小于2%.