基于镜像分析的空心导管光束整形原理研究

基于镜像原理,对空心导管LD面阵光束整形的原理和输出光场的特点进行了分析,并对LD面阵光束经过空心导管后的光强分布进行了仿真.发现空心导管将LD不同角度范围的光束进行分割,并在出射面内叠加的光束整形原理.通过仿真得出由于发散角较大以及各分割角度范围光束角度不连续,使出射面上的平顶光束发生畸变,只适于泵浦薄激光介质的结论.     

Concise synthesis of dopexamine dihydrochloride via benzyl protecting protocol

Benzyl protecting protocol was first employed in two routes for the concise synthesis of dopexamine dihydrochloride.This protecting group could be cleanly removed under mild condition and no unacceptable ion was brought to the final product.The total yield of route I was 43.8% from phenylacetic acid,while it was 54.1% of route II from 2-(3,4-bis(benzyloxy)phenyl)acetic acid.The titration purity of the final product was more than 99.5%,while any single or total impurities met the known standard of the drug by HPLC analysis.The measured residual palladium met an acceptable limit(<1 ppm) as an API for injection.     

Cascaded electron transition in CuWO_4/CdS/CDs heterostructure accelerating charge separation towards enhanced photocatalytic activity

CuWO_4,as an n-type oxide semiconductor with a bandgap of 2.2 eV,has stimulated enormous interest as a potential broad-spectrum-active photocatalyst for environmental pollution remediations.However,rapid charge recombination greatly hinders its practical applications.Herein,we present a cascaded electron transition pathway in a ternary heterostructure consisting of CdS quantum dots,carbon dots(CDs) and CuWO_4 hollow spheres,which proves to greatly facilitate the photogenerated electron-hole separation,and eventually boosts the degradation efficiency of phenol and congo red by 100% and 46%compared to bare CuWO_4.The enhanced performance of the CuWO_4/CdS/CDs heterostructure mainly originates from the unidirectional electron migration from CdS to CuWO_4 and then to the organics through CDs.This work elucidates the electron transfer kinetics in multi-phase system and provides a new design paradigm for optimizing the properties of CuWO_4 based photocatalysts.     

4-(4′-Diamino-di-phenyl)-sulfone supported on hollow magnetic mesoporous Fe3O4@SiO2 NPs: As a reusable and efficient catalyst for the synthesis of ethyl 2-amino-5,10-dihydro-5,10-dioxo-4-phenyl-4H benzo[g]chromene-3-carboxylates

4-(4′-diamino-di-phenyl)-sulfone supported on hollow magnetic mesoporous (HMMS) Fe₃O₄@SiO₂ NPs has been used as a novel and efficient catalyst in the preparation of ethyl 2-amino-5,10-dihydro-5,10-dioxo-4-phenyl-4H benzo[g]chromene-3-carboxylates by a simple one-pot three-component reaction of aldehydes, ethyl cyanoacetate and 2-hydroxynaphthalene-1,4-dione under reflux conditions in ethanol. Wide range of products, excellent yields in short times, reusability of the catalyst, low catalyst loading and environmental benignity are some of the important features of this protocol.     

Controlling morphology and particle size of hollow poly(styrene-divinylbenzene) microspheres fabricated by template-based method

Hollow poly(styrene–divinylbenzene) (P(S-DVB)) microspheres were fabricated via template-based method including synthesis of silica particles by sol-gel method, preparation of silica/P(S-DVB) particles by dispersion polymerization and chemical etching of silica cores by NaOH solution. TEM, FTIR and TG analyses confirmed that the hollow P(S-DVB) microspheres were successfully obtained. The morphology of hollow P(S-DVB) microspheres could be controlled by adjusting the amounts of DVB, AIBN and VTES, and the round-ball-like hollow P(S-DVB) microspheres were fabricated when the amount of DVB, AIBN and VTES was 30.0?wt%, 5.0?wt% and 30.0?vol% respectively. Both the size of silica particles and amount of monomers were regarded as the two key factors to control the particle size of the round-ball-like hollow P(S-DVB) microspheres.     

Determination of estrogens in wastewater using three-phase hollow fiber-mediated liquid-phase microextraction followed by HPLC

Three-phase hollow fiber-mediated liquid-phase microextraction followed by HPLC was used for the determination of three synthetic estrogens, namely diethylstilbestrol, dienestrol, and hexestrol, in wastewater. Extraction conditions including organic solvent, volume ratio between donor solution and acceptor phase, extraction time, stirring rate, donor phase and acceptor phase were optimized. The target compounds were extracted from a 10 mL aqueous sample at pH 1.5 (donor solution) through a 45 mm in length hollow polypropylene fiber that was immersed in 1-octanol in advance, and then the hollow fiber was filled with 10 microL 0.5 mol/L sodium hydroxide solution (acceptor phase). After a 40 min extraction, the acceptor phase was directly injected into an HPLC system for detection. Under the optimized extraction conditions, a large enrichment factor (more than 300-fold) was achieved for the three estrogens. The determination limit at an S/N of 3 ranged from 0.25 to 0.5 microg/L for the estrogens. The recovery ratio was more than 86% in the determination of these estrogens in wastewater.     

Heritability and linkage study on heart rates in a Mongolian population

Elevated heart rate has been proposed as an independent risk factor for cardiovascular diseases, but their interrelationships are not well understood. In this study, we performed a genome-wide linkage scan in 1,026 individuals (mean age 30.6 years, 54.5% women) from 73 extended families of Mongolia and determined quantitative trait loci that influence heart rate. The DNA samples were genotyped using deCODE 1,039 microsatellite markers for 3 cM density genome-wide linkage scan. Correlation analysis was carried out to evaluate the correlation of the covariates and the heart rate. T-tests of the heart rate were also performed on sex, smoking and alcohol intake. Consequently, this model was used in a nonparametric genome-wide linkage analysis using variance component model to create a multipoint logarithm of odds (LOD) score and a corresponding P value. In the adjusted model, the heritability of heart rate was estimated as 0.32 (P<.0001) and a maximum multipoint LOD score of 2.03 was observed in 77 cM region at chromosome 18. The second largest LOD score of 1.52 was seen on chromosome 5 at 216 cM. Genes located on the specified locations in chromosomes 5 and 18 may be involved in the regulation of heart rate.     

中空MOFs材料制备及电催化应用的研究进展

水分裂、金属-空气电池和燃料电池等能源转换技术对解决未来的能源危机和环境问题至关重要.氧还原反应(ORR)、氧析出反应(OER)和氢析出反应(HER)作为其核心反应,存在反应动力学速率较慢的问题,因此,开发研制高效的非贵金属电催化剂具有重要意义.金属有机骨架(MOFs)材料因具有高度可调的组成和多孔晶体结构,在不同的应用领域引起了越来越多的关注.中空MOFs纳米材料具有MOFs材料高度可调的组成和结构优势,又具有中空结构纳米材料的优点(如更快的物质传输、更丰富的孔隙率、灵活多变的活性组分、更多的暴露活性位点及对苛刻条件的更好相容性等),在电催化领域显现出巨大的应用潜力.本文对近几年来基于中空结构MOFs材料的制备及在电催化方面应用的研究进展进行了综合评述,并对该领域面临的挑战和发展前景进行了总结和展望.     

CoO纳米颗粒/石墨烯纳米纤维复合材料的制备及电化学性能

用石墨烯和Co(CH₃COO)₂·4H₂O作为原料,利用超声辅助法合成了锂离子电池的负极材料CoO纳米颗粒/中空石墨烯纳米纤维复合物.采用X射线衍射(XRD)确定材料的物相组成,采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)观察材料的表面形貌和微观结构,采用X射线光电子能谱(XPS)确定材料的价态结构.采用循环伏安、恒电流充放电和交流阻抗谱表征材料的电化学性能.结果显示,在100 mA/g的电流密度下,循环了160次后,可逆容量仍超过800 mA/g,库仑效率保持在99%以上.该材料优异的电化学性能主要归因于石墨烯的中空纤维结构,中空内部可以容纳电解液,能直接将离子输送到颗粒表面,实现了离子的快速传输;二维中空纤维搭建成三维网络结构,实现了三维电子传导网络.