硫化汞纳米组装链的诱导合成及其光学性能

选择一种高活性模板剂通过简单的诱导组装工艺, 合成了结构均一有序的硫化汞一维纳米组装链, 该纳米链由直径约为30 nm的粒子组装而成, 长度约0.6-1.0 μm. 通过XRD、TEM、FT-IR、UV-Vis光谱等手段对产物结构进行了表征. UV-Vis实验结果发现, 产物具有良好的紫外吸收性能. 产物对荧光素具有灵敏的荧光猝灭效应, 预计在微观修饰、纳米器件、样品检测等领域具有潜在的应用价值. 同时还对产物的形成机理做了初步探讨.     

含长碳链间隔臂结构的强碱性阴离子交换树脂的合成及热稳定性

研究了一种含长碳链间隔臂结构的强碱性阴离子交换树脂的新合成方法.评价了该树脂在水中的热稳定性.结果表明,以苯乙烯-二乙烯基苯共聚白球和1,3-噁嗪-2-酮为原料,季铵型离子液体为催化剂,得到带有胺丙基的苯乙烯-二乙烯基苯共聚珠体,再用甲酸和甲醛N-甲基化,溴乙烷季铵化,可以生成强碱交换量为1.86mmol/g强碱阴离子交换树脂.含长碳链间隔臂结构的OH~-型阴离子交换树脂在100℃去离子水中保持720h交换量仅下降11.83%,好于商业通用的强碱阴离子交换树脂.     

Synthesis and photovoltaic properties of poly(p-phenylenevinylene) derivatives with two triphenylamine and bithiophene conjugated side chains

Two soluble poly(p-phenylenevinylene) derivatives (PPVs) with two bithiophenes as conjugated side chains, P1 and P2, were synthesized and characterized for application in polymer solar cells (PSCs). The thermal, photophysical, electrochemical and photovoltaic properties of the PPVs were investigated and compared with those of the PPVs without conjugated side chains. Bulk heterojunction solar cell devices are fabricated using the copolymers as the electron donor and PCBM ([6,6]-phenyl-C₆₁-butyric acid methyl ester) as the electron acceptor. The power conversion efficiencies (η) based on the P1 and P2 are 1.1% and 1.41% under AM 1.5 illumination (100 mW/cm²), respectively.     

Approximate analysis and optimization of batch ordering policies in capacitated supply chains

Devising manufacturing/distribution strategies for supply chains and determining their parameter values have been challenging problems. Linking production management to stock keeping processes improves the planning of the supply chain activities, including material management, culminating in improved customer service levels. In this study, we investigate a multi-echelon supply chain consisting of a supplier, a plant, a distribution center and a retailer. Material flow between stages is driven by reorder point/order quantity inventory control policies. We develop a model to analyze supply chain behavior using some key performance metrics such as the time averages of inventory and backorder levels, as well as customer service levels at each echelon. The model is validated against simulation, yielding good agreement of robust performance metrics. The metrics are then used within an optimization framework to design the supply chain so as to minimize expected total system costs. The outcome of the optimization framework specifies how to move inventory throughout the supply chain and how to set inventory control parameters, i.e., reorder levels and replenishment batch sizes.     

Synthesis and Characterization of an Inorganic‐Organic Hybrid Layered Zinc Phosphite [(C2H3N3)Zn(HPO3)]

A inorganic‐organic hybrid zinc phosphite (C₂H₃N₃)Zn(HPO₃) ( 1 ) has been prepared under solvothermal conditions in the presence of 1,2,4‐triazole (trz) ligand.Its structure was determined by single‐crystal X‐ray diffraction, and further characterized by powder X‐ray diffraction (XRD), FTIR spectroscopy, elemental analysis, ICP analysis, thermogravimetric analysis and fluorescent spectrum. It crystallizes in the monoclinic system, space group P2₁/n, a = 7.5515(6) Å, b = 9.1813(8) Å, c = 10.0125(8) Å, β = 111.267(1)°, V = 646.92(9) ų, Z = 4. The structure consists of left‐handed and right‐handed helical chains that are connected through bridging oxygen atoms to form a two‐dimensional layer structure with 4.8‐net. The compound exhibits intense photoluminescence upon photo‐excitation at 326 nm.     

Antimicrobial Activity of Broth Fermented with Kefir Grains

Kefir grains originate from the Caucasus region and are used for preparing beverages using sugar solution, milk, and fruit juice. As long as they are formed by a microbial consortium useful in the intestine, the produced drinks can be called probiotics. The aim of this study was to determine the antimicrobial activity during kefir fermentation in sugar broth. Fermentations with three kinds of carbohydrates (molasses, demerara sugar, and brown sugar) as carbon source were carried out. Brown sugar promoted the greatest antimicrobial activities, producing inhibition halos corresponding to 35, 14, 12, 14, and 14 mm for Candida albicans, Salmonella typhi, Shigella sonnei, Staphylococcus aureus, and Escherichia coli, respectively. Different carbon source concentrations and the time of fermentation influenced the size of the inhibition halos of the pathogenic microorganisms.     

On finiteness of chains of intermediate rings

An extension of integral domains is said to have the “finite length of intermediate chains of domains” property (for short FICP) if each chain of intermediate rings between R and S is finite. The main purpose of this paper is to characterize when has FICP in case R ^* (the integral closure of R in S) is a finite dimensional semilocal domain. This generalizes a theorem due to Gilmer, in which S is the quotient field of R. Examples illustrating the sharpness and the limits of our results are settled.      

The differentiable chain functor is not homotopy equivalent to the continuous chain functor

Let S_∗ and be the functors of continuous and differentiable singular chains on the category of differentiable manifolds. We prove that the natural transformation , which induces homology equivalences over each manifold, is not a natural homotopy equivalence.     

A sequential data assimilation method based on the properties of a diffusion-type process

Data assimilation method, as commonly used in numerical ocean and atmospheric circulation models, produces an estimation of state variables in terms of stochastic processes. This estimation is based on limit properties of a diffusion-type process which follows from the convergence of a sequence of Markov chains with jumps. The conditions for this convergence are investigated. The optimisation problem and the optimal filtering problem associated with the search of the best possible approximation of the true state variable are posed and solved. The results of a simple numerical experiment are discussed. It is shown that the proposed data assimilation method works properly and can be used in practical applications, particularly in meteorology and oceanography.     

Direct Proof of Determinant Representation for Scalar Products of the XXZ Gaudin Model with Generic Non-Diagonal Boundary Terms

After constructing the Bethe state of the XXZ Gaudin model with generic non-diagonal boundary terms, we analyze the properties of this state and obtain the determinant representations of the scalar products for this XXZ Gaudin model.