Analysis of Infrared Divergence in OZI-Forbidden Decays of Orthoquarkonia

It is interesting to investigate the OZI-forbidden decays of orthoquarkoknium, J/ψ→γπ^0（γη,γη′）, J/ψ→π^＋π^-（π^0π^0）. At first glance, there is infrared divergence in the above processes. In this work, to clear the mist we use the factorization method with the light cone wavefunction of the final state light meson. We prove straightforwardly that the infrared divergence can be eliminated completely.     

Effects of Transverse Field on Internal Energy and Specific Heat of a Molecular-Based Materials

The molecular-based magnetic materials AFe^IIFe^III (C₂O₄)₃ have ahoneycomb structure in which Fe^III (S=2) and Fe^III (S=5/2) occupy sites alternately. They can be described as mixed spin-2 and spin-5/2 Ising model with ferrimagnetic interlayer coupling. The influences of the transversefield on the internal energy and the specific heat of the molecular-based magnetic system have been studied numerically by using the effective-field theory with self-spin correlations and the differential operator technique.     

激发功率、退火温度及Tm3+浓度对Tm3+/Er3+/Yb3+三掺YF3粉末上转换发光性质的影响

用水热法合成了Tm³⁺/Er³⁺/Yb³⁺三掺杂YF₃上转换发光粉末,并对其进行了结构和形貌表征.对上转换发射谱的研究表明,在相对低激发功率下,可以观察到比较明亮的近白色发光,且随着激发功率的增大,上转换发射强度迅速增大并达到饱和状态,继续增大激发功率,出现发光猝灭现象.退火温度对上转换发射强度的影响表明,随着退火温度的升高,Tm³⁺,Er³⁺的所有特征发射峰均相对增强.上转换发射谱随Tm³⁺浓度变化关系表明,在相对低Tm³⁺掺杂浓度下,Tm³⁺-Er³⁺相互作用占优势,Tm³⁺把能量传递给Er³⁺,Er³⁺发射相对增强;在相对高掺杂浓度下,Tm³⁺-Tm³⁺之间交叉弛豫过程占优势,Er³⁺发射相对减弱.从实验结果看出,该粉末的上转换发光非常丰富,从紫外到红外均有发射,是一种潜在的白色上转换发光及三维固体显示材料.     

1,6-二[(2'-苄胺甲酰基)苯甲氧基]己烷混合稀土配合物中镧、钆、钇对铕和铽荧光性能的影响

在氯仿和乙酸乙酯溶液中合成了1,6-二[(2′-苄胺甲酰基)苯甲氧基]己烷(L)的铕和铽的配合物,及其与La(Ⅲ)、Gd(Ⅲ)、Y(Ⅲ)的混合配合物。元素分析数据表明单—稀土硝酸盐与配体形成的是2:3型的配合物;通过红外光谱表征,混合配合物和单一配合物具有相似的配位结构。紫外光谱的数据表明,掺杂数量相同的其他离子会干扰Eu和Tb配合物对紫外光的吸收。对混合配合物的荧光进行了详细的研究,结果表明:La(Ⅲ)、Gd(Ⅲ)、Y(Ⅲ)对铕和铽的发光有显著的增强作用,但对其发射峰位的影响不大,三种离子中Gd³⁺的增强作用最大,且掺杂量对荧光增强作用也有影响。     

Control of the interparticle spacing in superparamagnetic iron oxide nanoparticle clusters by surface ligand engineering

Polymer-mediated self-assembly of superparamagnetic iron oxide(SPIO) nanoparticles allows modulation of the structure of SPIO nanocrystal cluster and their magnetic properties. In this study, dopamine-functionalized polyesters(DApolyester) were used to directly control the magnetic nanoparticle spacing and its effect on magnetic resonance relaxation properties of these clusters was investigated. Monodisperse SPIO nanocrystals with different surface coating materials(poly(ε-caprolactone), poly(lactic acid)) of different molecular weights containing dopamine(DA) structure(DA-PCL2k,DA-PCL1k, DA-PLA1k)) were prepared via ligand exchange reaction, and these nanocrystals were encapsulated inside amphiphilic polymer micelles to modulate the SPIO nanocrystal interparticle spacing. Small-angle x-ray scattering(SAXS)was applied to quantify the interparticle spacing of SPIO clusters. The results demonstrated that the tailored magnetic nanoparticle clusters featured controllable interparticle spacing providing directly by the different surface coating of SPIO nanocrystals. Systematic modulation of SPIO nanocrystal interparticle spacing can regulate the saturation magnetization(Ms) and T_2 relaxation of the aggregation, and lead to increased magnetic resonance(MR) relaxation properties with decreased interparticle spacing.     

Bianchi Type I String Dust Magnetized Cosmological Models in Lyra Geometry

Bianchi type I string dust cosmological models in the presence and absence of magnetic field in the frame work of Lyra geometry are investigated. To get the deterministic model of the universe, we assume that the eigenvalue (σ₁¹ ) of shear tensor (σ_i ^j ) is proportional to expansion (θ ). This leads to A =(BC)ⁿ, where A, B, C are metric potentials and n is a constant. To discuss the results in terms of cosmic time t, we have considered n = 1. The physical and geometrical aspects of the models and singularities in the models are also discussed.     

氯化氢共振多光子电离光谱：F1Δ2态的光谱微扰分析

通过共振多光子电离-飞行时间法, 记录了氯化氢分子在84800-85700 cm^-1范围内, F¹Δ₂ (v’=1) 里德堡态以及V¹∑⁺ (v’=13, 14) 离子对态的电离产物H⁺, ³⁵Cl⁺, H³⁵Cl⁺ 及其同位素的光谱数据. 由于受离子对态V¹∑⁺ 的作用, F¹Δ₂ (v’=1)态呈现出明显的近共振相互作用特性. 为了分析F¹Δ₂与V¹∑⁺态之间存在的光谱微扰, 基于光解离电离通道的分析, 并针对F¹Δ₂ (v’=1)态离子信号比的变化, 将离子信号二能级作用模型优化到三能级的作用模型, 计算得到了微扰强度值为0.6 cm^-1, 预解离系数γ为0.025. 此外, 对于F¹Δ₂ (v’=1) 与V¹∑⁺ (v’=13, 14)态的三个振动能级的光谱峰位置, 采用光谱解微扰法拟合, 同样得到了类似的微扰强度和去微扰后的各光谱参数. 研究表明, 激发至F¹Δ₂ (v’=1)态得到的H⁺, Cl⁺ 离子主要是该态通过与离子对态耦合作用而产生, 而F¹Δ₂ (v’=1) 态光谱位置偏移不仅受离子对态而且还受其他里德堡态作用的影响. 同时, 非零γ 值证实了F¹Δ₂态预解离的存在. 关键词： 光解离电离 里德堡态 离子对态 光谱微扰     

New Approach for Solving Master Equations in Quantum Optics and Quantum Statistics by Virtue of Thermo-Entangled State Representation

By introducing a fictitious mode to be a counterpart mode of the system mode under review we introduce the entangled state representation <η |, which can arrange master equations of density operators ρ(t) in quantum statisticsas state-vector evolution equations due to the elegant properties of <η |. In this way many master equations (respectively describing damping oscillator, laser, phase sensitive, and phase diffusion processes with different initial density operators) can be concisely solved. Specially, for a damping process characteristic of thedecay constant κ we find that the matrix element of ρ (t) at time t in <η| representation is proportional to that of the initial ρ₀ in the decayed entangled state <ηe^-κt| representation, accompanying with a Gaussian damping factor. Thus we have a new insight about the nature of the dissipative process. We also set up the so-called thermo-entangled state representation of density operators, ρ=∫(d²η /π)< η | ρ> D(η), which is different from all the previous known epresentations.     

Effect of Dissipative Environments on Atomic-State Quantum Teleportation

In the paper, taking the atomic EPR entanglement states as quantum channel, we investigate the fidelity of quantum teleportation of atomic state in thermal environment and vacuum reservoir by means of quantum theory of damping-density operator approach, and the average fidelities are calculated. the resultsshow that the atomic quantum channel state |ø> = (1/2^1/2)(| 00>+ |11>) is more robust than | Φ> = (1/2^1/2)(|01> + |10>) in teleportation process when they are subject to the dissipative environments.     

Calculation of Energy and Other Properties of Muonic Helium Atom Using Boundary Conditions of Wave Function

The properties of muonic helium atom (⁴He⁺²μ^-e^-) in ground state are considered. In this work, the energy and average distance between particles have been obtained using a wave function, which satisfies boundary conditions. It is shown that the obtained energy are very close to the values calculated by others. But the small differences of the expectation values of r²ⁿare due to the incorporated boundary conditions in proposed wave function and are expected.     

A Note on q-Deformed Two-Dimensional Yang-Mills and Open Topological Strings

In this note we make a test of the open topological string version of the OSV conjecture in the toric Calabi-Yau manifold X=O(-3)→ P² with background D4-branes wrapped on Lagrangian submanifolds. The D-brane partition function reduces to an expectation value of some inserted operators of a q-deformedYang-Mills theory living on a chain of P¹'s in the base P² of X. At large $N$ this partition function can be written as a sum over squares of chiral blocks, which are related to the open topological string amplitudes in the local P² geometry with branes at both the outer and inner edges of the toric diagram. This is in agreement with the conjecture.     

Fe_3O_4纳米颗粒/聚二甲基硅氧烷复合材料磁电容效应的研究

提出了一种以Fe3O4纳米颗粒和聚二甲基硅氧烷(PDMS)组成的复合材料为介质的平行板磁电容结构,并对其产生的磁电容效应的特点以及影响磁电容效应的因素进行了研究.对不同粒径的Fe3O4纳米颗粒按不同比例与PDMS混合形成的复合材料进行了测试.研究表明,与无磁场情况相比,在外磁场作用下,Fe3O4纳米颗粒/PDMS复合材料的电容值和介电损耗均发生了改变,产生了磁电容效应.由该复合材料磁电容效应所产生的电容变化量随着纳米颗粒混合浓度的增大而增大,并且当纳米颗粒粒径尺寸大于常温超顺磁临界尺寸时,材料的电容变化量随着颗粒尺寸的减小而增大.     

Production of Charged Higgs Bosons from Left-Right Twin Higgs Model at TeV Energy e-γ Colliders

The left-right twin Higgs (LRTH) model predicts the existence of three additional Higgs bosons: one neutral Higgs ø⁰ and a pair of charged Higgs bosons ø^±. In this paper, we study two pair production processes of these new particles at the next generation eγ colliders, i.e., e^-γ → e^-ø⁺ø^-, ande^-γ→ ν_Rø^-ø⁰. We find that the production cross section of the process e^-γ →e^-ø⁺ø^- are at the level of several tens fb, the production cross section of the process e^-γ→ν_Rø^-ø⁰ can reach 0.35 fb with the reasonable parameter values. As long as the charged Higgs bosons are not too heavy, we conclude that these processes might be used to test for the left-right twin Higgs model in future high-energy linear collider experiments.     

NLO Corrections of HTC Π0 and Π+Π- Pair Production at ILC in TC2 Model

As well known, if the Higgs boson were not observed at LHC, the technicolor model would be the most favorable candidate responsible for the symmetry breaking. To overcome some defects in the previous model, some extended versions have been proposed. In the TC2 model typical signature is existence of heavy H_TC and technipion Π. A direct proof of validity of the model is to produce them at accelerator. Thus we study the production rates of e⁺ e^- → H_TCΠ⁰ and e⁺ e^- → Π⁺ Π^- at ILC in the topcolor-assisted technicolor (TC2) model. In fact, there is a flood of models belonging to new physics, which can result in products withcharacteristics similar to H_TC+Π of the TC2 model. Therefore to distinguish this model from others one may need to investigate some details by calculating the cross section to NLO. We indeed find that the NLO corrections are significant, namely the ratio δ ≡ (σ_NLO- σ_LO)/σ_LO in e⁺ e^- → H_TC Π⁰ exceeds 100% within a plausible parameter space.     

优化磁共振纳米医学中磁性纳米粒子的热疗效率

磁共振热疗(magnetic resonance hyperthermia)是近年来新兴的一种纳米医学治疗方法,由磁共振的硬件架构产生特定交变磁场,有效地加热磁性纳米粒子,以直接或间接地杀死癌细胞,体现诊疗一体化。提高磁性纳米粒子的加热效率是当前磁共振热疗领域亟待解决的难题之一。磁性纳米粒子的加热效率不仅与粒子本身的大小、性质以及尺寸分布有关,还和聚集状态有关。该研究利用3D Metropolis蒙特卡罗模拟方法,模拟了不同温度下磁性纳米粒子的磁共振热动力学行为及其团聚与分离现象;并通过修正过的郎之万方程,建立了相变临界温度与外加磁场频率的函数关系。模拟结果显示,磁性纳米粒子悬浮液中多聚体的相对含量随着温度的升高而降低,达到临界温度后,多聚体完全分离成单体;而提高交变磁场频率可以显著降低临界温度,且存在临界频率,高于此临界频率后临界温度不再受外加磁场频率影响,达到稳定。因而在临界频率下预热磁性纳米粒子悬浮液,使得多聚体分离成单体,可优化磁性纳米粒子的热疗效率。     

Relativistic Magnetosonic Solitary Wave in Magnetized Multi-Ion Plasma

In the presence of an applied uniform magnetic field Bo, the properties of 2-dimensional （2D） magnetosonic solitary waves of relativistic amplitude in the plasma containing electron, light ions He^＋, and heavy ions O＋ are presented. In the weakly relativistic limit, a Kadomtsev Petviashvili （KP） equation is derived by reductive perturbation method. We give the N-soliton solution of the KP equation and find dromion solutions of a potential of the physical field. The interaction law of the dromions is obtained, which shows there is no exchange of energy, momentum, and angular momentum before and after interaction of the dromions except for phase shifts.     

B → Ds(*) η (') Decays in Perturbative QCD

In this paper, we calculate the branching ratios for B⁺ → D_s⁺η, B⁺ → D_s⁺η ', B⁺ → D_s^*+η, and B⁺ → D_s^*+η ' decays by employing the perturbative QCD (pQCD) factorization approach. Under the two kinds of η-η' mixingschemes, the quark-flavor mixing scheme and the singlet-octet mixingscheme, we find that the calculated branching ratios agree well withthe currently available experimental upper limits. We also consider the so called ``f_{D_s} puzzle', by using two groups of parameters about the D^(*)_s meson decay constants, that are f_{D_s}=241 MeV, f_{D^*_s}=272 MeV and f_{^D_s=}274 MeV, f_{D^*_s}=312 MeV, to calculate the branching ratios for theconsidered decays. We find that the results change 30% by usingthese two different kinds of paramters.     

Complex-Variable Fokker-Planck Equation Solved in Entangled State Representation

We lind that the Fokker-Planck equation in complex variables can be conveniently solved in the context of bipartite entangled state representation and its relationship with SU（2） Lie algebraic generators＇ new realization {（1/4）[（Q1 - Q2）^2 ＋ （P1＋ P2）^2], （1/4）[（Q1 ＋Q2）^2＋ （P1 - P2）^2], and -（i/2）（Q1P2 ＋ Q2P1）}, the quadratic combination of canonical operators.     

Radiative Decays of (0+,1+) Strange-Bottom Mesons

In this article, we assume that the (0⁺,1⁺) strange-bottom mesons are the conventional b\bar{s} mesons, and calculate the electromagnetic coupling constants d, g₁, g₂, and g₃ using the light-cone QCD sum rules. Then we study the radiative decays B_{s0 →} B_s* γ, B_{s1→ ^{Bs* γ,}} B_{s1 →} B_s* γ, and B_s1→ B_{s0 ^γ}, and observe that the widths are rather narrow. We can search for the (0⁺,1⁺) strange-bottom mesons in the invariant B_s π⁰ and B_s*π⁰ mass distributions in the strongdecays or in the invariant B_s*γ and B_s^γ mass distributions in the radiative decays.     

A Few Remarks on Milburn Equation

After presenting the infinite operator-sum form solution to the Milburnequation d ρ/dt=γ (Uρ U⁺-ρ ) =γU[ρ,U⁺], where U=exp(-i H/\hbar{γ}), and verifying that this equation preserves the three necessary conditions of density operators during time evolution, we prove that the von Neumann entropy increases with time. We also point out that if A and B both obey the Milburn equation, then the product AB obeys (d/dt)( AB) =γ U[ AB,U⁺] -(1/γ) (dA/dt)(dB/dt), which violates the Milburn equation, this reflects that a pure state will evolve to a mixture in general.