Liouville type theorems for a system of integral equations on upper half space

In this paper,we consider the following system of integral equations on upper half space {u(x) = ∫Rn + (1/|x-y|n-α-1/|-y|n-α) λ1up1(y) + μ1vp2(y) + β1up3(y)vp4(y) dy;v(x) = ∫Rn + (1/|x-y|n-α-1/|-y|n-α)(λ2uq1(y) + μ2vq2(y) + β2uq3(y)vq4(y) dy,where Rn + = {x =(x1,x2,...,xn) ∈ Rn|xn 0}, =(x1,x2,...,xn-1,-xn) is the reflection of the point x about the hyperplane xn= 0,0 α n,λi,μi,βi≥ 0(i = 1,2) are constants,pi≥ 0 and qi≥ 0(i = 1,2,3,4).We prove the nonexistence of positive solutions to the above system with critical and subcritical exponents via moving sphere method.     

Crystal structure and standard molar enthalpy of formation of ethylenediamine dilauroleate (C12H24O2)2C2N2H8(s)

The crystal structure of ethylenediamine dilauroleate was determined by X-ray crystallography. A thermochemical cycle was designed in accordance with Hess law. The enthalpy change of the synthesis reaction of ethylenediamine dilauroleate was determined to be $ \Updelta_{{\text{r}}} H_{{\text{m}}}^{\Uptheta } $ Δ r H m Θ  = ?(49.07 ± 0.11) kJ mol^?1 by an isoperibol solution–reaction calorimeter. The standard molar enthalpy of formation of the title compound was calculated to be $ \Updelta_{\text{f}} H_{\text{m}}^{\Uptheta } $ Δ f H m Θ  = ?(38.78 ± 0.43) kJ mol^?1 by the designed thermochemical cycle, the enthalpies of dissolution and other auxiliary thermodynamic quantities.     

Low-temperature heat capacities, and thermodynamic properties of solid–solid phase change material bis(1-octylammonium) tetrachlorocuprate

A new crystalline complex (C₈H₁₇NH₃)₂CuCl₄(s) (abbreviated as C₈Cu(s)) was synthesized by liquid phase reaction. Chemical analysis, elemental analysis, and X-ray crystallography were applied to characterize the composition and crystal structure of the complex. Low-temperature heat capacities of the complex were measured by a precision automatic adiabatic calorimeter over the temperatures ranging from 78 to 395 K, and two solid–solid phase changes appeared in the heat capacity curve. The temperatures, molar enthalpies and entropies of the two phase transitions of the complex were determined to be: T _{trs, 1} = 309.4 ± 0.35 K, Δ_trs H _{m, 1} = 16.55 ± 0.41 kJ mol^?1, and Δ_trs S _{m, 1} = 53.49 ± 1.3 J K^?1 mol^?1 for the first peak; T _{trs, 2} = 338.5 ± 0.63 K, Δ_trs H _{m, 2} = 6.500 ± 0.10 kJ mol^?1, and Δ_trs S _{m, 2} = 19.20 ± 0.28 J K^?1 mol^?1 for the second peak. Two polynomial equations of the heat capacities as a function of the temperature were fitted by least-square method. Smoothed heat capacities and thermodynamic functions of the complex relative to the standard reference temperature of 298.15 K were calculated based on the fitted polynomial equations.     

非线性两能级系统中的Landau-Zener-Coulomb跃迁

非线性跃迁动力学的研究是量子操控中的一个重要课题,在原子分子光物理、量子信息以及固体物理等领域都有着重要的应用.本文研究了具有粒子间相互作用两能级系统中的Landau-Zener-Coulomb跃迁动力学.结果表明,对于能级的斜率正负不同的情况,粒子间相互作用对系统跃迁动力学的影响完全不同.为正时,粒子间相互作用总是抑制能级间的非绝热跃迁,且相互作用强度越大,两能级间的非绝热跃迁越难发生.而为负时,弱相互作用会促进能级间的非绝热跃迁,在强相互作用情况下,跃迁概率会出现振荡.随着相互作用强度的增大,振荡幅度逐渐减小,能级间的非绝热跃迁受到抑制.     

Synthesis and infrared and fluorescence spectra of new europium and terbium polynuclear complexes with an amide-based 1,10-phenanthroline derivative

An amide-based 1,10-phenanthroline (phen) derivative and its complexes with europium(III) and terbium(III) ions were synthesized. The complexes were characterized by elemental analysis, infrared spectra and conductivity. The europium and terbium ions were coordinated by O atoms of C=O, Ar-O-C and N atoms of phen. The fluorescence properties of the complexes in THF, dioxane, MeCN and DMF were investigated. Under the excitation of UV light, these complexes exhibited characteristic fluorescence of europium and terbium ions. The solvent factors influencing the fluorescent intensity were discussed.     

Correlated vortex pinning in Si-nanoparticle doped MgB2

The magnetoresistivity and critical current density of well characterized Si-nanoparticle doped and undoped Cu-sheathed MgB₂ tapes have been measured at temperatures T≥28 K in magnetic fields B≤0.9 T. The irreversibility line B_irr(T) for doped tape shows a stepwise variation with a kink around 0.3 T. Such B_irr(T) variation is typical for high-temperature superconductors with columnar defects (a kink occurs near the matching field B_?) and is very different from a smooth B_irr(T) variation in undoped MgB₂ samples. The microstructure studies of nanoparticle doped MgB₂ samples show uniformly dispersed nanoprecipitates, which probably act as a correlated disorder. The observed difference between the field variations of the critical current density and pinning force density of the doped and undoped tape supports the above findings.     

First synthesis of silicalite-1 from a dry powder system via solid-solid transformation

Silicalite-1 has first been synthesized from a dry powder system with an adsorbedstate template, and is presented as a convincing example for direct solid-solid transformation process.     

空间目标的可见光散射与红外辐射

利用Lowtran7大气传输模型计算了0．4～0．8μm可见光波段的太阳辐射、大气自身的热辐射以及天地背景辐射。利用粗糙面光散射理论与双向反射分布函数计算了空中目标表面对太阳辐射、云层对阳光反射的散射。并利用传热学和背景辐射理论，根据能量守恒定律建立了空间目标表面温度的热平衡方程。以气球为例，计算了不同表面涂层材料的气球在不同地理位置、不同高度、不同时间、温度及辐射功率的变化。分析了空间目标红外辐射特性的一般规律和特征。     

掺杂Cu^2＋的ZnS纳米超微粒的PVA复合膜的制备和时间分辨光谱的研究

报导了ＺｎＳＣｕ水溶液和ＺｎＳＣｕ／ＰＶＡ复合膜的制备过程，分析了分散剂所起的作用．研究了室温下复合膜的激发光谱和发射光谱，以及室温和液氮温度下的分时光谱．初步探讨了ＺｎＳＣｕ纳米超微粒的发光过程．