全同费米子与玻色子系统中的SU(3)动力学

基于群代数理论,描述了如何构建s, d两轨道能级下的全同费米子体系与全同玻色子体系四极-四极相互作用动力学,据此探讨了全同性原理对核多体系统动力学结构的影响。结果表明,给定粒子数情况下全同费米子体系中低自旋态的空间维数的要比全同玻色子系统中同样自旋态的空间维数大得多,意味着同等条件下前者包含更多更丰富的转动带结构。本工作分析展示了一个基于SU(3)群代数理论分析核结构模型的简单实例。     

Contribution of Glycerol on Production of Poly(γ-Glutamic Acid) in <Emphasis Type="Italic">Bacillus subtilis</Emphasis> NX-2

Glycerol would stimulate the production of poly(γ-glutamic acid) (γ-PGA) and decrease its molecular weight in Bacillus subtilis NX-2. When 20 g/l glycerol was added in the medium, the yield of γ-PGA increased from 26.7 ± 1.0 to 31.7 ± 1.3 g/l, and molecular weight of γ-PGA decreased from 2.43 ± 0.07 × 10⁶ to 1.86 ± 0.06 × 10⁶ Da. In addition, it was found that the decrease of γ-PGA chain length by glycerol would lead to the decrease of broth viscosity during the fermentation and enhanced the uptake of substrates, which could not only improve cell growth but also stimulate γ-PGA production. Moreover, it was also found that glycerol could effectively regulate molecular weight between 2.43 ± 0.07 × 10⁶ and 1.42 ± 0.05 × 10⁶ Da with the concentration ranging from 0 to 60 g/l. This was the first time to discover such contribution of glycerol on γ-PGA production in Bacillus genus. And the effects of glycerol on molecular weight of γ-PGA would be developed to be an approach for the regulation of microbial γ-PGA chain length, which is of practical importance for future commercial development of this polymer.     

Synthesis of silica-coated ZnO nanocomposite: the resonance structure of polyvinyl pyrrolidone (PVP) as a coupling agent

The preparation of silica-coated ZnO nanocomposite using polyvinyl pyrrolidone (PVP) as a coupling agent was investigated. Transmission electron microscopy analysis revealed that silica has been deposited on the surface of PVP-capped ZnO nanoparticles as a continuous thin layer. Two-dimensional correlation analysis based on the time-dependent UV–vis spectra was introduced to study the interaction governing the deposition of silica on to PVP-capped ZnO. Strong hydrogen bonds formed between the amphiphilic PVP molecules and silica in the silica-coated PVP-capped ZnO composites. The reduced photocatalytic activity of silica-coated ZnO nanoparticles will enhance their performance as durable, safe, and non-reactive UV blockers in plastics, paints, and coating for outdoor textile and timber products.     

Hamiltonian cycles and 2-dominating induced cycles in claw-free graphs

Let G = (V, E) be a connected graph. For a vertex subset , G[S] is the subgraph of G induced by S. A cycle C (a path, respectively) is said to be an induced cycle (path, respectively) if G[V(C)] = C (G[V(P)] = P, respectively). The distance between a vertex x and a subgraph H of G is denoted by , where d(x, y) is the distance between x and y. A subgraph H of G is called 2-dominating if d(x, H) ≤ 2 for all . An induced path P of G is said to be maximal if there is no induced path P′ satisfying and . In this paper, we assume that G is a connected claw-free graph satisfying the following condition: for every maximal induced path P of length p ≥ 2 with end vertices u, v it holds:

Application of a multi-dentate amphiphilic compound to transfer silver nanoparticles into an organic solvent

A multi-dentate amphiphilic compound, 3,3'-(dodecylazanediyl)-bis-[N-(2-aminoethyl)propanamide] (12C-2NH2) has been synthesized. The molecular structure was characterized by Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-vis) spectra, nuclear magnetic resonance (NMR) spectra, and fast atom bombardment mass (FAB-MS) spectra. 12C-2NH2 was employed to stabilize silver nanoparticles. Surface properties and stability of silver nanoparticles were controlled by adjusting the 12C-2NH2 to silver (0) molar ratio. 12C-2NH2 was also applied to transfer silver nanoparticles from an aqueous to an organic phase. The transfer efficiency depends on 12C-2NH2 concentration. When 12C-2NH2 to silver (0) molar ratio was 2:1, the highest efficiency of phase transfer to toluene was obtained. These 12C-2NH2 stabilized silver nanoparticles are very stable over a period of four days in toluene.     

Durable phosphorus/nitrogen flame retardant for cotton fabric

Cellulose - A new phosphorus/nitrogen flame retardant (FR) containing reactive –P–O−NH4+ groups was synthesized from glycerol, phosphoric acid, and urea. At high temperatures, the...     

电化学发光反转录聚合酶链式反应技术检测齿兰环斑病毒

发展高效的病毒检测技术已成为当今生物学研究的热点之一。本研究将反转录聚合酶链式反应(PCR)技术与电化学发光分析方法结合起来,用于检测兰花中齿兰环斑病毒。检测过程中采用生物素标记的探针与PCR产物杂交,可起到筛选特异性产物的作用,从而避免假阳性结果的产生。三联吡啶钌标记探针与PCR产物杂交,既可以起到进一步筛选目的片段的作用,又可与分析液中的三丙胺反应,从而产生光信号,被电化学发光仪所检测到。在引物的5′端分别连接一段特异性核酸序列,既提高了钌探针与特异性产物的杂交几率,又增强了样品检测信号,从而提高了信躁比。实验结果表明:此方法灵敏度高、稳定性好、操作简单,可以从兰花样品中准确地检测到齿兰环斑病毒,有望发展成为一种高效的病毒检测方法。     

Controlled synthesis of ZnS quantum dots and ZnS quantum flakes with graphene as a template

Novel ZnS quantum dots (QDs) and ZnS quantum flakes (QFs) were successfully prepared with graphene nanosheets (GNs) as a special template, and two unique heterostructures of ZnS/GNs were also obtained. Due to the structure-directing template effect of GNs, the as-synthesized ZnS with different morphologies, dots or flakes, were uniformly distributed on the surface of GNs by controlling nucleation and growth. The two different heterostructures of ZnS/GNs exhibited obvious photovoltaic response, and ZnS/GN QFs-on-sheet heterostructures show higher photovoltage than that of ZnS/GN QDs-on-sheet.