Orientably-regular embeddings of a class of multipartite graphs

The orientably-regular embeddings of complete multipartite graphs have been determined by the contributions of several papers. After that, a natural question can be asked: How about the regular embeddings of the multipartite graphs with m parts, while each part contains n vertices(not necessarily complete multipartite). In this paper, we classify all the orientably-regular embeddings of these graphs when m is a prime q and n is a prime power pe.     

Superconvergence and recovery type a posteriori error estimation for hybrid stress finite element method

Superconvergence and recovery type a posteriori error estimators are analyzed for Pian and Sumihara's 4-node hybrid stress quadrilateral finite element method for linear elasticity problems. Superconvergence of order O(h~(1+min){α,1}) is established for both the displacement approximation in H~1-norm and the stress approximation in L~2-norm under a mesh assumption, where α 0 is a parameter characterizing the distortion of meshes from parallelograms to quadrilaterals. Recovery type approximations for the displacement gradients and the stress tensor are constructed, and a posteriori error estimators based on the recovered quantities are shown to be asymptotically exact. Numerical experiments confirm the theoretical results.     

Evaluation of non-covalent interaction between Seryl-Histidine dipeptide and cyclophilin A using NMR and molecular modeling

Science China Chemistry - Seryl-Histidine dipeptide (Ser-His) has been previously reported to be capable of cleaving DNAs and carboxyl esters, as well as proteins. The protein cleavage mechanism...     

Electrochemical behavior of uranium(III) in NaCl–KCl molten salt

The electro-redox behavior of uranium(III) on Mo electrode in NaCl–KCl molten salt in the temperature range 973–1073 K has been investigated using cyclic voltammetry electrochemical method and so on, such research will help to understand uranium behavior in pyro-reprocessing. The results showed that UCl₃ could be reduced into uranium metal in a quasi-reversible one-step process exchanging three electrons. The diffusion coefficients of U(III) ions were determined and the activation energy for diffusion was found to be 55.794 kJ mol⁻¹. The apparent standard potentials of U(III)/U(0) at several temperatures were calculated. The thermodynamic properties of UCl₃ have also been investigated.

     

Biocatalytic direct asymmetric aldol reaction using proteinase from Aspergillus melleus

The direct asymmetric aldol reaction of aromatic aldehydes with cyclic or acyclic ketones was catalyzed by proteinase from Aspergillus melleus (AMP) in acetonitrile in the presence of water. A wide range of substrates could be transformed into the corresponding aldol products in yields up to 89%, enantioselectivities up to 91% ee and diastereoselectivities up to >99:1 (anti/syn). This work provided an example of enzyme catalytic promiscuity that widens the applicability of this biocatalyst in organic synthesis without the need for additional cofactors or special equipment.     

A facile synthesis of goodyeroside A from (<Emphasis Type="Italic">S</Emphasis>)-malic acid

Goodyeroside A 1, a natural product with hepatoprotective activity, was efficiently synthesized in a total yield of 47% in five steps starting from (S)-malic acid. The spectral data of the target compound 1 is identical with those of the natural product.     

Statistical Entropy of Reissner-Nordstrom Black Hole Computed by Generalized Uncertainty Principle

The equation of state density is corrected by the generalized uncertainty principle. Statistical entropy of scalar field outside Reissner-Nordstrom black hole is computed by WKB approximation method. The result shows that this black hole entropy is proportional to its horizon area, which is the same as that given by brick-wall method. The difference from the brick-wall method is that the present result is convergent without any cutoff.     

全自动凯氏定氮仪在测定干旱区土壤中全氮量的研究

本实验采用了UDK159全自动凯氏定氮仪对干旱区土壤全氮量的方法以及试验部分影响因素进行研究,结果表明：精密度试验中RSD在0.01919%～0.1073%之间(≤1%),用标准物质硫酸铵进行回收率检验,其回收率达99.5% 以上,检测准确度和精密度都符合国家标准的要求;在消化时间的选择上,变异系数为0.0088,表明土壤中有机物在30 min时已完全消化;而关于硫酸用量在10~15mL时为最佳值,干旱区土壤中氮一般含量为(0.260±0.003) %(P =0.95)。