三苯胺衍生物分子非线性光学性质的理论研究

在密度泛函理论水平上,利用响应函数方法,研究了1-{(1E)-2-[4-(二苯胺基)苯基]乙烯基}-4-[4-N,N-二甲胺]苯(PVMB)和1-[(1E)-2-(4-(1E)-2-{4-[4-N,N-二甲胺]苯基}乙烯基)苯基]苯胺}苯基)乙烯基]-4-[4-N,N-二甲胺]苯(DPVMB)两分子的双光子吸收特性.计算结果表明,这两个化合物都具有较好的双光子吸收特性,且具有两分支结构的DPVMB分子比具有单支结构的PVMB分子有更强的双光子吸收强度.计算数值结果和实验结果符合地较好.     

Resonance states of atomic Di-anions

Metastable states of O (2-), S (2-), B (2-), and Al (2-) are studied in the framework of the complex absorbing potential method using highly correlated multireference configuration interaction wave functions. The first row species O (2-) and B (2-) are found to be broad resonances showing widths of roughly 1.7 eV, whereas the second row systems S (2-) and Al (2-) possess widths clearly smaller than 1 eV. The identified resonance states are compared to the fundamental H (2-) resonance, and the relationship with recent electron scattering experiments is discussed.     

Contribution of Electron-Positron Vacuum Polarization to Energy Level of Exotic Atoms

Energy levela of (ππ)-,(πK)-,(KK)-, - and (πμ)- exotic atoms are calculated in the framework of Logunov-Tavkhelidze quasipotential approach. The analytic expressions for the contributions of electron-positron vacuum polarization are derived. Corrections from strong interactions are calculated according to the formula Deser.     

Study of charmless hadronic B meson decays to pseudoscalar-vector final states

We report results of searches for charmless hadronic B meson decays to pseudoscalar( pi(+/-), K+/-, pi(0), or K(0)(S))-vector( rho, K(*), or omega) final states. By using 9.7x10(6) BB pairs collected with the CLEO detector, we report the first observation of B(-)--->pi(-)rho(0), B(0)-->pi(+/-)rho(-/+), and B(-)-->pi(-)omega, which are expected to be dominated by hadronic b-->u transitions. The measured branching fractions are (10.4(+3.3)(-3.4)+/-2.1)x10(-6), (27.6(+8.4)(-7.4)+/-4.2)x10(-6), and (11.3(+3.3)(-2.9)+/-1. 4)x10(-6), respectively. Branching fraction upper limits are set for all of the other decay modes investigated.     

EMR and optical study of Mn2+ doped potassium trihydrogen selenite

The EMR study of Mn2+ doped potassium trihydrogen selenite is performed and the site of Mn2+ in the lattice is discussed. The zero field parameters providing good fit to the observed EMR spectra are estimated. The spin-Hamiltonian parameters g, A, B, D, and a are (2.0003 +/- 0.0002), (31 +/- 2) x 10(-4), (20 +/- 2) x 10(-4), (87 +/- 2) x 10(-4), and (-9 +/- 1) x 10(-4) cm(-1), respectively. The percentage of covalency of the metal-ligand bond is also determined. The optical absorption study suggests the lattice distortion in the crystal. The electron repulsion and crystal field parameters having good fit to the observed optical spectra are evaluated. The band positions are fitted with the Racah parameters (B and C), the cubic crystal field splitting parameters (Dq), and the Trees correction (alpha). The values of B, C, Dq, and alpha are 871, 2967, 670, and 76 cm(-1), respectively.     

Resolved fine structure of exciton complexes bound to phosphorus impurities in silicon

A Fabry-Pérot interferometer is used to observe resolved fine structure for two of the luminescence lines associated with exciton complexes bound to phosphorus impurities in silicon. The results are interpreted in terms of j-j couplings for the electrons and holes and give support for the recently proposed shell-model. Linewidths are obtained for the four luminescence lines associated with 1-, 4-, 5-, and 6- exciton complexes. The linewidths of the 4-, 5-, and 6- exciton peaks are found to be considerably broader than that of the single bound exciton.     

Study of tau decays to six pions and a neutrino

The tau decays to six-pion final states have been studied with the CLEO detector at the Cornell Electron Storage Ring. The measured branching fractions are B(tau(-)-->2pi(-)pi(+)3pi(0)nu(tau)) = (2.2+/-0.3+/-0.4)x10(-4) and B(tau(-)-->3pi(-)2pi(+)pi(0)nu(tau)) = (1.7+/-0.2+/-0.2)x10(-4). A search for substructure in these decays shows that they are saturated by intermediate states with eta or omega mesons. We present the first observation of the decay tau(-)-->2pi(-)pi(+)omega(nu)tau and the branching fraction is measured to be (1.2+/-0.2+/-0.1)x10(-4). The measured branching fractions are in good agreement with the isospin expectations but somewhat below the conserved-vector-current predictions.     

克尔介质中光波的自衍射效率的理论计算

采用前向四波耦合的理论模型研究了薄克尔介质的厚度，吸收，入射光强等因素对光波自射效率的影响，详细分析了光波的位相变化，位相失配以及二波混频项的作用。     

不同方法制备的CO2-3替换磷灰石固溶体晶体化学的FTIR研究

采用不同方法制备了CO2-3替换的磷灰石固溶体,利用FTIR结合XRD对其进行了晶体化学研究,结果表明均相沉淀法制备的碳羟磷灰石(CHAP)属B型替换且替换方式是[CO3·OH]四面体替换[PO4]四面体;固相离子交换法制备的CHAP属A型替换且替换方式是[CO3]三角形配位体替换通道位置的OH-;固相反应法制备的碳氟磷灰石(CFAP)属B型替换,其替换方式是[CO3·F]四面体替换[PO4]四面体;sol-gel法制备的CHAP属AB混合型替换,其Ψ3分裂为Ψ3-1,Ψ3F,Ψ3-4.高斯函数法拟合表明Ψ3F峰是A型替换的Ψ3-2与B型替换的Ψ3-3的叠合.当WCO2-3＜3.34%时,随CO2-3含量增加,A型替换量增大,且当WCO2-3=3.34%时达最大值,当3.34%＜WCO2-3＜7.52%时,随CO2-3含量增加,B型替换量增大,且当WCO2-3= 7.52%时亦到饱和.     

Quantum dynamics of ultracold Na+ Na2 collisions

Ultracold collisions between spin-polarized Na atoms and vibrationally excited Na2 molecules are investigated theoretically, using a reactive scattering formalism (including atom exchange). Calculations are carried out on both pairwise additive and nonadditive potential energy surfaces for the quartet electronic state. The Wigner threshold laws are followed for energies below 10(-5) K. Vibrational relaxation processes dominate elastic processes for temperatures below 10(-3)-10(-4) K. For temperatures below 10(-5) K, the rate coefficients for vibrational relaxation (v=1-->0) are 4.8x10(-11) and 5.2x10(-10) cm(3) s(-1) for the additive and nonadditive potentials, respectively. The large difference emphasizes the importance of using accurate potential energy surfaces for such calculations.     

放射性核素铀在针铁矿中的占位研究

用第一性原理研究放射性同位素铀在针铁矿(α-FeOOH)中的占位情况, 分别考虑铀原子替代针铁矿中的铁的替位缺陷和铀的多种八面体和多种四面体间隙缺陷. 计算发现了三个最稳定的缺陷构型, 它们分别对应于一个铀替位缺陷(S) 及其中的一个铀的八面体(O)和四面体(T)间隙缺陷, 其形成能分别为-13.49, -3.86, -1.60 eV. 也研究了两个相邻的铀原子在针铁矿中的占位情况, 发现双铀原子很容易掺入到相邻的SS或OS位, 它们的形成能分别为-27.392和-16.214 eV, 结合能分别为-0.417和1.131 eV. 表明双原子铀在针铁矿中会以SS形式发生偏聚而较难以OS形式偏聚. 关键词： 铀 针铁矿 占位 第一性原理     

First observation of the decays B(0) → D(+)K(-)π(+)π(-) and B(-) → D(0)K(-)π(+)π(-)

First observations of the Cabibbo-suppressed decays B(0) → D(+)K(-)π(+)π(-) and B(-) → D(0)K(-)π(+)π(-) are reported using 35 pb(-1) of data collected with the LHCb detector. Their branching fractions are measured with respect to the corresponding Cabibbo-favored decays, from which we obtain B(B(0) → D(+)K(-)π(+)π(-))/B(B(0) → D(+)π(-)π(+)π(-))=(5.9±1.1±0.5)×10(-2) and B(B(-) → D(0)K(-)π(+)π(-))/B(B(-) → D(0)π(-)π(+)π(-))=(9.4±1.3±0.9)×10(-2), where the uncertainties are statistical and systematic, respectively. The B(-) → D(0)K(-)π(+)π(-) decay is particularly interesting, as it can be used in a similar way to B(-) → D(0)K(-) to measure the Cabibbo-Kobayashi-Maskawa phase γ.     

聚合物O-PPV的链间相互作用的研究

近年来,聚对苯乙炔(PPV)及其衍生物作为一类性能优良的电致发光材料而受到人们的广泛关注[1].这是因为聚合物发光材料能通过化学裁剪方法来改善发光效率、颜色、成膜性等特性.载流子形成激子以及激子的辐射和非辐射衰减过程向来是聚合物发光二极管(LEDs)发光的重要环节,因此研究聚合物的光物理过程对提高器件的发光特性是非常重要的.     

关于氯离子对银胶体系SERS效应的进一步增强机理

在一些情况下添加氯离子能引起表面增强拉曼散射的进一步增强,本文提出了SERS效应中氯离子在银胶粒子和分子之间搭桥,从而促成吸附并引进一步增强的观点。设计了实验,验证了该观点的正确性。     

Measurement of branching fractions and polarization in B-->phiK(*) decays

We present the first measurement of decay amplitudes in B-->phiK* and measurements of branching fractions in B-->phiK(*) decays based on 78.1 fb(-1) of data recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- storage ring. The decay amplitudes for the different phiK*0 helicity states are measured from the angular distributions of final state particles in the transversity basis. The longitudinal and transverse complex amplitudes are |A0|2=0.43+/-0.09+/-0.04, |A(perpendicular)|2=0.41+/-0.10+/-0.04, arg((A(parallel))=-2.57+/-0.39+/-0.09, and arg((A(perpendicular))=0.48+/-0.32+/-0.06. The direct CP-violating asymmetries are found to be consistent with zero.     

Observation of B+/- -->omegaK+/- decay

We report the first observation of the charmless two-body mode B+/--->omegaK+/- decay, and a new measurement of the branching fraction for the B+/--->omegapi(+/-) decay. The measured branching fractions are B(B+/--->omegaK+/-)=(9.2(+2.6)(-2.3)+/-1.0)x10(-6) and B(B+/--->omegapi(+/-))=(4.2(+2.0)(-1.8)+/-0.5)x10(-6). We also measure the partial rate asymmetry of B+/--->omegaK+/- decays and obtain A(CP)=-0.21+/-0.28+/-0.03. The results are based on a data sample of 29.4 fb(-1) collected on the Upsilon(4S) resonance by the Belle detector at the KEKB e(+)e(-) collider.     

A high sensitive fiber Bragg grating cryogenic temperature sensor

At cryogenic temperature, a fiber Bragg grating （FBG） temperature sensor with controllable sensitivity and variable measurement range is demonstrated by using bimetal configuration. In experiments, sensitivities of -51.2, -86.4, and -520 pm/K are achieved by varying the lengths of the metals. Measurement ranges of 293 - 290.5, 283 - 280.5, and 259 - 256.5 K are achieved by shortening the distance of the gap among the metals.     

Antireflective films optimization of ZnS ceramics infrared windows

The transmittance characteristics of ZnS ceramics with infrared (IR) (3-5 and 8-12μm) antireflective coatings are studied. The film designs are optimized with programmed software. A double-side and double-layer scheme is employed. Two different double-layers with proper pa ameters are coated onto each side of a ZnS substrate. The measurement methods for transmittance are investigated. The measured transmittance for IR (3-5 and 8-12μm) surpasses 70%.     

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基于微波奇偶模理论、叠加原理和阻抗匹配理论分析设计了3-dB功率分配器的结构参数,使用高频电磁场仿真软件HFSS进行结构仿真和参数优化,得到了最优结果：输入端口1的反射损耗RL=-41.42dB;1和4端口的隔离度Iso=-44.86dB;输出端口2、3的功分度为-3.02 dB和-3.01 dB;输入驻波比VSWR=1.017。     

HL-2A装置低杂波天线3-dB功分器设计

基于微波奇偶模理论、叠加原理和阻抗匹配理论分析设计了3-dB功率分配器的结构参数,使用高频电磁场仿真软件HFSS进行结构仿真和参数优化,得到了最优结果：输入端口1的反射损耗RL=-41.42dB;1和4端口的隔离度Iso=-44.86dB;输出端口2、3的功分度为-3.02 dB和-3.01 dB;输入驻波比VSWR=1.017。