On the Nuclear Effects of Valence Quark Distributions and Sea Quark Distributions

In this paper we present a method which may be used to get the nuclear effect functions R_υ^A(x_t) and R_s^A(x_t) for valence quark distributions and sea quark distributions in the light of the data of 1-A deep inelastic scattering and nuclear Drell-Yan process. Both the functions may be used to test the theoretical models explaining the nuclear effects. With nuclei Fe, Ca and C as examples, the results are shown.     

One- and Two-Mode Combination Squeezing Operator for Two Harmonic Oscillators with Coordinate-Momentum Coupling

By virtue of the technique of integration within an ordered product of operators, we derive the normal ordering expansion of a one- and two-mode combination squeezing operator for two harmonic oscillators with coordinate- momentum coupling. It turns out that this squeezing operator just diagonalizes the Hamiltonian H=p^21/2m1＋m1ω^21x^21/2＋p^222m2＋m2ω^22x^22/2-λx2p1 so its ground state is a one- and two-mode combination squeezed state. Quantum fluctuation in the ground state is calculated.     

THE CONVERSION OF GLUONS INTO QUARKS AND THE MULTIQUARK STATES

The rate for the conversion of the gluon into a color octet quark pair which subsequently forms a multiquark state with another quark pair or a gluon is discussed. The static potential in a [(QQ)₈(qq)_8,1] state where Q=c,b and q=u, d is studied in the MIT bag model. It is shown that the repulsive Coulomb force between Q and Q is dominant at small QQ separations, which would significantly suppress the QQ wave function at the origin. For the charm quark (Q=c) the ratio of |Ψ(O)|² for the ordinary (QQ)₁ to that for the(QQ)₈ in the [(QQ)₈(qq)_8,1] state is estinated to be 2-5. Therefore the assumption |Ψ₈(O)|²=|Ψ₁(O)|² would lead to an overestimation for the rate of g*→QQ and it is necessary to take the suppression effect of the repulsive Coulomb force into consideration.     

Structures of（ΩΩ）0＋and（[1]Ω）1＋in Extended Chiral SU（3） Quark Model

The structures of (ΩΩ)0 and ([1]Ω)1 are studied in the extended chiral SU(3) quark model in which vector meson exchanges are included. The effect from the vector meson fields is very similar to that from the one-gluon exchange (OGE) interaction. Both in the chiral SU(3) quark model and in the extended chiral SU(3) quark model,di-omega (ΩΩ)0 is always deeply bound, with over one hundred MeV binding energy, and ([1]Ω)1 ‘s binding energy is around 20 MeV. An analysis shows that the quark exchange effect plays a very important role for making di-omega (ΩΩ)0 deeply bound.     

Ba10(PO4)4(SiO4)2∶Eu2+荧光体的光谱特性

采用高温固相法合成了荧光体Ba₁₀（PO₄）₄（SiO₄）₂：Ce³⁺和Ba₁₀（PO₄）₄（SiO₄）₂：Eu²⁺,研究了两种荧光体的光谱特性。结果表明,两者都呈现较强的宽带激发特征。根据同种基质中Eu²⁺和Ce³⁺两种离子光谱特征的相关性,通过测得的Ba₁₀（PO₄）₂（SiO₄）₂基质中Ce³⁺的光谱数据估算了Ba₁₀（PO₄）₂（SiO₄）₂：Eu²⁺中Eu²⁺的斯托克斯位移（ΔS）和激发能量,估算结果与Ba₁₀（PO₄）₂（SiO₄）₂：Eu²⁺样品的光谱分析结果十分吻合。Ba₁₀（PO₄）₂（SiO₄）₂：Eu²⁺可以同时被紫光和蓝光激发,发出偏白的绿光,可用作白光LED的荧光粉。     

BaGd2(MoO4)4:Tb3+,Eu3+荧光粉的 发光特性与能量传递机理

利用高温固相法制备了BaGd_2(MoO_4)_4∶Tb~(3+)与BaGd_2(MoO_4)_4∶Tb~(3+),Eu~(3+)荧光粉,并借助于X射线衍射(XRD)、激发光谱、发射光谱及荧光衰减曲线对样品的结构及发光性能进行了表征。在290 nm激发下,BaGd_2(MoO_4)_4∶Tb~(3+)样品在550 nm处具有较强的绿光发射,表明该样品可用作绿色荧光粉。Tb~(3+)离子的最佳掺杂浓度为50%,电偶极间相互作用是引起浓度猝灭效应的主要原因。当在BaGd_2(MoO_4)_4∶Tb~(3+)荧光粉中共掺入Eu~(3+)离子后,可同时观测到Tb~(3+)与Eu~(3+)离子的特征发射峰。随Eu~(3+)掺杂浓度的升高,Tb~(3+)离子的发光强度逐渐下降,而Eu~(3+)离子的发光强度逐渐增加。根据BaGd_2(MoO_4)_4∶Tb~(3+),Eu~(3+)中Tb~(3+)离子的荧光寿命计算了Tb~(3+)与Eu~(3+)离子间的能量传递效率,并根据荧光寿命与激活离子掺杂浓度的关系证实了能量传递机制为电偶极间相互作用。     

铁电单晶(KxNa1-x)0.4(SryBa1-y)0.8Nb2O6的光学性质和线性电光效应

本文介绍铁电单晶(K_xNa_1-x)_0.4(Sr_yBa_1-y)_0.8Nb₂O₆的光学性质和线性电光效应的测量。实验结果表明,这种晶体具有较大的光学双折射,透光范围由4000?到5.6μm。晶体具有低的线性电光调制的半波电压,其电光调制价值指数n₀³·γ_c高达730×10 关键词：     

AlH~+离子5个Λ-S态和10个?态的光谱性质以及激光冷却的理论研究

利用考虑Davidson修正的内收缩多参考组态相互作用(icMRCI+Q)方法结合相关一致基组aug-ccpV6Z计算了AlH~+离子前两个离解极限对应的5个Λ-S态和10个?态的势能曲线.为了提高势能曲线的可靠性和精确性,计算中考虑了自旋轨道耦合效应、芯电子价电子相关和标量相对论修正以及将势能外推至完全基组极限.基于得到的势能曲线,获得了束缚和准束缚的4个Λ-S态和8个?态的光谱常数和振动能级,与已有的实验结果符合.计算了2(1/2)→X~2Σ_(1/2)~+和A~2Π_(3/2)→X~2Σ_(1/2)~+跃迁的跃迁偶极距.利用计算的精确的势能曲线和跃迁偶极矩,获得了2(1/2)~(第一势阱)(υ′=0, 1)→X~2Σ_(1/2)~+(υ′′)和A~2Π_(3/2)(υ′=0, 1)→X~2Σ_(1/2)~+(υ′′)跃迁的高度对角化分布的Franck-Condon因子(f_(00)和f_(11))和大的振动分支比;预测了2(1/2)~(第一势阱)(υ′=0, 1)和A~2Π_(3/2)(υ′=0, 1)态短的自发辐射寿命和窄的辐射宽度,这适合于AlH~+离子的快速激光致冷.所需的3束激光冷却波长都在紫外区域.这些结果表明了激光冷却AlH~+离子的可行性.此外,评估了自旋轨道耦合效应对光谱常数、振动能级和激光冷却AlH~+离子的影响.     

一个新的自由能函数对介电高弹薄膜的多组等双轴预拉伸下力电耦合实验的预测

当介电高弹聚合物薄膜被施以面内等双轴预拉伸后, 受到厚度方向的电压作用时, 薄膜在力场和电场共同作用下产生大变形. 电场采用Maxwell应力分析, 力场采用橡胶弹性模型分析. 拟合这类变形的常用橡胶弹性模型主要有Neo-Hookean, Arruda-Boyce, Gent等模型. 这些模型对实验数据的定量拟合存在不同程度的偏差. 通过对实验数据的分析, 结合数学方法, 提出了一个新的自由能函数模型. 通过该模型对VHB4905介电高弹聚合物薄膜的多组等双轴预拉伸电力耦合实验进行拟合, 并以Neo-Hookean, Gent模型作为对照, 结果与实验数据拟合很好, 比对照模型的偏差明显缩小.     

Na4Ca3(AlO2)10∶Eu2+,Mn2+荧光粉的发光特性

采用高温固相法,制得一种新型荧光粉Na₄Ca₃(AlO₂)₁₀∶Eu²⁺,Mn²⁺。样品的结构和发光性质分别由X射线衍射谱和荧光光谱来表征。在Na₄Ca₃(AlO₂)₁₀∶Eu²⁺的激发光谱中出现了Eu²⁺的f-d跃迁吸收带;在发射光谱中,出现蓝光发射,峰值位于441 nm。当在Na₄Ca₃(AlO₂)₁₀∶Eu²⁺中掺杂Mn²⁺时,发生了Eu²⁺→Mn²⁺的能量传递,在542 nm处出现了Mn²⁺的发射峰。在Na₄Ca₃(AlO₂)₁₀∶Eu²⁺,Mn²⁺中,随着Mn²⁺浓度的增加,Eu²⁺粒子的发射强度减弱,而Mn²⁺粒子的发射强度增强,且Eu²⁺离子发射的衰减时间缩短,同时色度由蓝光移向白光。     

SrZn2(PO4)2:Sn2+,Mn2+荧光粉的发光性质及其能量传递机理

采用高温固相法制备了SrZn₂(PO₄)₂:Sn²⁺(SZ₂P:Sn²⁺), SrZn₂(PO₄)₂:Mn²⁺(SZ₂P:Mn²⁺), SrZn₂ (PO₄)₂:Sn²⁺, Mn²⁺(SZ₂P:Sn²⁺, Mn²⁺) 荧光粉. 通过X射线衍射、激发和发射光谱详细研究了荧光粉的物相和发光性质. 在SrZn₂(PO₄)₂ 基质中, Sn²⁺离子发射光谱是峰值位于461 nm宽带谱, 归属于Sn²⁺离子的³P₁→¹S₀能级跃迁, SZ₂P:Mn²⁺激发光谱由基质吸收带(200–300 nm)和位于352, 373, 419, 431和466 nm的一系列激发峰组成, 分别对应Mn²⁺离子的⁶A₁(⁶S)→⁴E(⁴D), ⁶A₁(⁶S)→⁴T₂(⁴D), ⁶A₁(⁶S)→[⁴A₁(⁴G), ⁴E(⁴G)], ⁶A₁(⁶S)→⁴T₂(⁴G)和⁶A₁(⁶S)→⁴T₁(⁴G)能级跃迁, 因此, SZ₂P:Sn²⁺ 的发射光谱与SZ₂P:Mn²⁺的激发光谱有较大范围的重叠. 结果表明Sn²⁺对Mn²⁺发光有明显的敏化作用. 基于Dexter电多极相互作用能量传递公式和Reisfeld近似原理分析, 荧光粉SZ₂P:Sn²⁺, Mn²⁺中Sn²⁺-Mn²⁺离子之间的能量传递机理属于电四极-电四极相互作用引起的共振能量传递, 并计算出Sn²⁺-Mn²⁺离子之间能量传递临界距离R_c ≈ 1.78 nm. 通过改变Sn²⁺, Mn²⁺离子掺杂浓度, 实现了荧光粉发光颜色的调节, 在254 nm短波紫外激发下荧光粉发出较强的蓝白光. 研究结果表明SZ₂P:Sn²⁺, Mn²⁺荧光粉有望应用于紧凑型节能灯照明领域, 随着半导体紫外芯片技术的发展, 有潜力应用于未来的白光发光二极管照明领域.     

Energy Spectra and g Factors of α-A1203:Cr3+ and α-A1203:Mn4+

By diagonalizing the complete d³ energy matrix in a trigonally distorted cubicfield and using the wavefunctions from it, unified calculations of the whole energy spectrum as well as the g factors of the ground state and t₂^{3 2} E excited states for α-A1₂0₃:Cr³⁺ and α-A1₂0₃:Mn⁴⁺ have been carried out respectively. A11 the calculated results are in very good agreement with the experimental data. The comparison between the results of the two crystals has been made, which demonstrates that the covalency of α-A1₂0₃:Mn⁴⁺ is stronger than the one of α-A1₂0₃:Cr³⁺. For the zero-field splittings of the ground state and t₂^{3 2} E , their physical origins are revealed; the comparison and analysis of their values of the two crystals have been made.     

EPR evidence of local lattice mode in K3H(SO4)2 and Rb3H(SO4)2 fast-proton conductors

The observation of an anomalous temperature dependence of Mn²⁺ EPR spectra linewidth and nonaxial crystal-field parameter in K₃H(SO₄)₂ and Rb₃H(SO₄)₂ allows one to suggest the presence of “local mode” predicted by Yamada (Ferroelectrics 170 (1995) 23). The activation energy for this kind of excitation was found and equals 11.3 (0.5) and 7.4 (0.3) meV for Mn²⁺ doped K₃H(SO₄)₂ and Rb₃H(SO₄)₂, respectively.     

LiGd(W_yMo_(1-y))_2O_(8-x/2)F_x∶Eu~(3+)红色荧光粉的制备和发光特性

采用高温固相法制备了LiGd(W_yMo_(1-y))_2O_(8-x/2)F_x∶0.4Eu~(3+)(x=0~1,y=0~1)系列白光LED用红色荧光粉。通过扫描电子显微镜、X射线衍射仪、红外光谱仪、荧光光谱仪对荧光粉的形貌、结构、光学性能进行了表征。结果表明,Eu~(3+)、F-和WO_4~(2-)的掺杂没有改变LiGd(MoO_4)_2的四方晶系白钨矿结构;F~-和WO_4~(2-)最佳掺杂量分别为x=0.6,y=0.4。在396 nm激发下,LiGd(W_(0.4)Mo_(0.6))_2O_(7.7)F_(0.6)∶0.4Eu~(3+)的发光强度比未掺杂样品提高了60%,量子效率可达66.23%。当温度升高至100℃时,样品的发射强度降为25℃时的76.6%。在460 nm激发下,样品的最强窄带发射峰位于617 nm处,归属于~5D_0→~7F_2跃迁,色坐标为(0.649 9,0.346 3)。5D0能级的荧光寿命曲线遵循单指数规律衰减,随着F-掺杂浓度的增加,5D0能级的荧光寿命不断增加,归因于低声子能量的F-掺入有效减小了能量的无辐射跃迁概率。所制备的LiGd(W_(0.4)Mo_(0.6))_2O_(7.7)F_(0.6)∶0.4Eu~(3+)荧光粉有望应用于白光LED。     

Unified Treatment of Systematics for Even-Even Nuclei with A≥70

By the concept of effective boson numbers, systematics of E₂₁+E₄₁+E₆₁+, R=E₂₁+/E₄₁, B(E2, 0₁⁺→2₁⁺) and Q₀ for even-even nuclei with A≥70 are presented. New features of energy spectra are noticed and an intuitive understanding is given.     

铥原子收敛于4f13(2F7/2o)6s(7/2,1/2)4o和4f13(2F7/2o)6s(7/2,1/2)3o偶宇称里德伯系列能级的电子关联效应

本文在多通道量子亏损理论框架下,利用相对论多通道理论,计算了铥原子收敛于4f¹³（²F_7/2^o）6s（7/2,1/2）₄^o和4f¹³（²F_7/2^o）6s（7/2,1/2）₃^o的三个偶宇称里德伯系列.通过将计算结果与美国国家标准与技术研究院数据进行比较,展示了两种类型的电子关联效应：1）里德伯系列之间的相互作用,导致里德伯系列的能级出现整体偏移;2）一个孤立的干扰态镶嵌在一个里德伯系列中,破坏了该里德伯系列能级的规则性.     

Comparisons Between Additional Parton Evolution and Q2-Rescaling Models Based on Recombination Effect

Comparisons between the additional parton evolution (APE) model and Q²-rescaling (QR) model based on the recombination effect are made by means of investigating deep-inelastic (DIS) structure functions F₂^A, nuclear Drell-Yan process and nuclear gluon distributions. While explaining experimentally measured F₂^A(x) structure functions, the difference in the recombination results of the two models mainly lies in their sensitivity to input parton distributions and Q²-dependence. In predicting the nuclear Drell-Yan ratio, the APE model gives more reasonable results in the small x region than those of the QR model. The two motlels offer similar predictions of the nuclear gluon ratio G_sn(x)/G_c(x) which are extracted from the inelastic J/ψ production process.     

运动磁单极子的规范势

本文利用诱导SU(2)规范势A_μ=?_μn×n的一些性质,从磁单极子的辐射电磁场强的已知表达式出发,构造出一个n场,使得由它得到的诱导势经约化之后得到的U(1)场强与磁单极子的辐射电磁场强一致。n得到之后,就得到SU(2)规范势,再经约化,就得到相等价的U(1)势,既然它的场强与磁单极子场强一致,它的U(1)势就是磁单极子的U(1)势,这个U(1)势是有奇异的(奇异弦),可以用分区表示的方法来避免它,当粒子静止时,这个势的结果与著名的吴-杨势一致。 关键词：     

First-principles Study on the Magnetic,Half-metal and Thermoelectric Transport Properties of Inorganic-Organic Hybrid Compounds [C4N2H12][Fe4Ⅲ(HPO3)2(C2O4)3]

The electronic structure, magnetic and half-metal properties of inorganic-organic hybrid compound [C₄N₂H₁₂][Fe₄^Ⅲ(HPO₃)₂(C₂O₄)₃] are investigated by using the full-potential linearized augmented plane wave (FPLAPW) method within density-functional theory (DFT) calculations. The density of states (DOS), the total energy of the cell and the spontaneous magnetic moment of [C₄N₂H₁₂][Fe₄^Ⅱ(HPO₃)₂(C₂O₄)₃] are calculated. The calculation results reveal that the low-temperature phase of [C₄N₂H₁₂][Fe₄^Ⅲ(HPO₃)₂(C₂O₄)₃] exhibits a stable ferromagnetic (FM) ground state, and we find that this organic compound is a half-metal in FM state. In addition, we have calculated antiferromagnetically coupled interactions, revealing the existence of antiferromagnetic (AFM), which is in agreement with the experiment. We have also found that [C₄N₂H₁₂][Fe₄^Ⅲ(HPO₃)₂(C₂O₄)₃] is a semiconductor in the AFM state with a band gap of about 0.40 eV. Subsequently, the transport properties for potential thermoelectric applications have been studied in detail based on the Boltzmann transport theory.     

Theoretical study of spin-forbidden cooling transitions of indium hydride using ab initio methods

The feasibility of spin-forbidden cooling of the In H molecule is investigated based on ab initio quantum chemistry calculations. The potential energy curves for the X~1Σ_(0~+)~+, a~3Π_~(0~-), a~3Π_(0~+), a~3Π_1, a~3Π_2, A~1Π_1, 1~3Σ_(0~-)~+, and 1~3Σ_1~+states of In H are obtained based on multi-reference configuration interaction plus the Davidson corrections method. The calculated spectroscopic constants are in good agreement with the available experimental data. In addition, the influences of the active space and spin–orbit coupling effects on the potential energy curves and spectroscopic constants are also studied. For Re of a~3Π_(0~-), a~3Π_(0~+), a~3Π_1, and a~3Π_2 states, the error from large active space is small. The potential energy curve of the A~1Π_1state is not smooth for small active space. The spin–orbit coupling effects have great influences on the potential well depth and equilibrium internuclear distance of the A~1Π state. The Franck–Condon factors and radiative lifetimes are obtained on the basis of the transition dipole moments of the a~3Π_(0~+) → X~1Σ_(0~+)~+, a~3Π_1 → X~1Σ_(0~+)~+, and A~1Π_1 → X~1Σ_(0~+)~+ transitions. Our calculation indicates that the a~3Π_1( ν'= 0) → X~1Σ_(0~+)~+(ν = 0) transition provides a highly diagonally distributed Franck–Condon factor and a short radiative lifetime for the a3Π1 state, which can ensure rapid and efficient laser cooling of In H.The proposed laser drives a~3Π_1 → X~1Σ_(0~+)~+ transitions by using three wavelengths.