Quantum Mechanical Virial Theorem in Systems with Translational and Rotational Symmetry

Generalized virial theorem for quantum mechanical nonrelativistic and relativistic systems with translational and rotational symmetry is derived in the form of the commutator between the generator of dilations G and the Hamiltonian H. If the conditions of translational and rotational symmetry together with the additional conditions of the theorem are satisfied, the matrix elements of the commutator [G,H] are equal to zero on the subspace of the Hilbert space. Normalized simultaneous eigenvectors of the particular set of commuting operators which contains H, J ², J _z and additional operators form an orthonormal basis in this subspace. It is expected that the theorem is relevant for a large number of quantum mechanical N-particle systems with translational and rotational symmetry.     

TEM and XPS studies on CdS/CIGS interfaces

Copper indium gallium selenide (CIGS) was deposited by metallic precursors sputtering and subsequently submitted to a selenization process. The upper CdS layers were deposited by chemical bath deposition (CBD) technique. The CdS/CIGS interfaces were investigated by Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). As checked by XPS analysis, the CIGS surface exhibited a hydroxide-terminated CdSe layer when treated with Cd Partial Electrolyte solution (Cd PE). Its thickness was roughly estimated to several nanometers. A 100 nm thick CdS layer was deposited onto CIGS surface. The TEM images revealed a clear and sharp interface between CdS and CIGS. XPS analysis showed a CIGS surface covered by a pinhole free and homogeneous CdS layer. XPS depth profile measurement of the CdS/CIGS interface did not evidence elemental inter-diffusion between the CIGS and CdS layers, in very good agreement with TEM observations.     

Two-component Poisson mixture regression modelling of count data with bivariate random effects

Two-component Poisson mixture regression is typically used to model heterogeneous count outcomes that arise from two underlying sub-populations. Furthermore, a random component can be incorporated into the linear predictor to account for the clustering data structure. However, when including random effects in both components of the mixture model, the two random effects are often assumed to be independent for simplicity. A two-component Poisson mixture regression model with bivariate random effects is proposed to deal with the correlated situation. A restricted maximum quasi-likelihood estimation procedure is provided to obtain the parameter estimates of the model. A simulation study shows both fixed effects and variance component estimates perform well under different conditions. An application to childhood gastroenteritis data demonstrates the usefulness of the proposed methodology, and suggests that neglecting the inherent correlation between random effects may lead to incorrect inferences concerning the count outcomes.     

Catalytic Enantioselective Protonation of Monofluorinated Silyl Enol Ethers towards Chiral α‐Fluoroketones

Described herein is an organocatalytic enantioselective protonation of monofluorinated silyl enol ethers, affording an array of optically active α‐secondary α‐fluoroketones in good to high yields and enantioselectivities, under the catalysis of bifunctional cinchonidine derived squaramide C4 . It represents a rare example of facile synthesis of enantioenriched α‐secondary α‐fluoroketones. With D₂O as the deuterium source and MeOD as the solvent, the first highly enantioselective preparation of chiral α‐deuterated α‐fluoroketones in >92% deuteration is developed.     

共价键合指示剂染料光学敏感膜的制备与性质

将1-(2-吡啶偶氮)-2-萘酚与溴丙烯反应合成具有末端双键的指示剂染料——1-(2-吡啶偶氮)-2-烯丙氧基萘,并与甲基丙烯酸羟丙脂、二甲基丙烯酸乙二醇脂在表面硅烷化过的普通玻璃片上进行共聚合,制得共价固定吡啶偶氮萘基染料分子的光学薄膜.以Cu2+离子为例测试了敏感膜的光学响应性能,结果表明所得材料对溶液中Cu2+具有良好的响应性能.该膜在使用过程中无脱落现象,重复使用6次其相对偏差小于6％.     

A metastable liquid state miscibility gap in undercooled Pd–Ni–P melts

Recently, phase separation was found to occur in Pd_41.25Ni_41.25P_17.5 bulk metallic glasses (BMG), which have a negative heat of mixing among the constituent elements. In this work, Pd_40 + 0.5xNi_40 + 0.5xP_20 ? x BMG with x = 0 to 3.5, were studied for amorphous phase separation. It occurs for x ? 1, but absent for x ? 1. In addition, in phase-separated specimens, the characteristic sizes or wavelengths of the decomposed phases were measured. It was found that they obey the lever rule. The experimental results suggest the existence of a metastable liquid/amorphous miscibility gap. Its origin is attributed to unique short range orders in the undercooled Pd–Ni–P melts.     

光谱法研究Leu-ENK与ct-DNA的相互作用

亮氨酸脑啡五肽是动物体内一种具有很强生物活性的阿片肽,在生物体内有极其重要的作用.利用紫外光谱和荧光光谱法研究了亮氨酸脑啡五肽(Leu-ENK)与小牛胸腺DNA(ct-DNA)的相互作用.研究表明,Leu-ENK-ct-DNA体系随着Leu-ENK浓度增大,体系的紫外光谱呈增色效应；随着ct-DNA浓度的增加,体系Le...     

Average distribution of k-free numbers in arithmetic progressions

We obtain a new bound on the average value of the error term in the asymptotic formula for the number of k-free numbers in arithmetic progressions. In particular, we improve the results of J. Gibson (2014) and C. Hooley (1975).     

Comparative study on the determination of ethyl p-methoxycinnamate in Kaempferia galanga rhizome by HPTLCS and HPLC

JPC – Journal of Planar Chromatography – Modern TLC - Ethyl p-methoxycinnamate (EPMC) is the main active ingredient in Kaempferia galanga rhizome (KGR). At present, the correlation...