High pressure X-ray diffraction study of SrMnO3 perovskite

Using a diamond anvil cell device and synchrotron radiation, the in-situ high-pressure structure of SrMnO₃ has been investigated. At pressure up to 28.6 GPa, no pressure-induced phase transition is observed. The lattice parameters as a function of pressure is reported, and the relationship of the axial compression coefficients is β_a>β_c. The isothermal bulk modulus K₂₉₈=266(4) GPa is also obtained by fitting the pressure-volume data using the Murnaghan equation of state.     

X射线荧光光谱分析痕量稀土元素检出限的研究

本文是在原有工作基础上，对低量稀土元素的ＸＲＦＡ方法，提高灵敏度，降低检出限，作了系统论述。主要以降低背景，提高峰背比，以及提高稳定性等方面进行了研究。     

IRMA／SXGX实验室信息管理系统

IRMA/SXGX是一个综合性的实验室信息管理系统,它由实验室异种机网络、计算机辅助化学子系统和办公自动化管理子系统组成,该系统在UNIX或XENIX操作系统下的多用户分时微型机和DOS操作系统的微型机上运行。目前已有六种分析仪器的计算机和五台中西文终端以及两台打印机联入该系统,能自动传输和管理实验室信息。这种多功能的信息管理系统有助于扩大分析测试服务领域,提高工作效率,改善分析结果的准确性。本文对该系统的设计策略、硬件配置、软件运行环境和系统功能作了介绍。     

萃取法富集XRF光谱测定岩石,土壤中的痕量元素

本文研究了用10%N_(7402)-MIBK萃取预富集,以XRFS测定岩石、土壤中Pb、Zn、Cu、Cd、Mo、Bi、Sn等痕量元素的方法,并研究了背景对检出限的影响,选Sm作内标。确定了样品分解,薄样制备方法和测定条件,检出限较直接粉末压片法约降低两个数量级,精密度通常优于4%,本法分析结果与标样推荐值吻合。     

Asymmetric aza-Henry reaction with α-substituted nitroacetates catalyzed by a bifunctional thiourea-guanidine catalyst

The asymmetric aza-Henry reaction of α-substituted nitroacetates and N-Boc imines was achieved with a new-type thioureaguanidine bifunctional organocatalyst.The novel transformations exhibited high diastereoselectivities,and the adducts bearing adjacent quaternary and tertiary chiral centers were generally obtained in moderate to good enantioselectivities(up to 88%ee).     

Sorption of norfloxacin from aqueous solutions by activated carbon developed from Trapa natans husk

The low-cost activated carbon was prepared from a renewable aquatic plant residue,Trapa natans husk,and tested for its ability to remove norfloxacin (NOR) from aqueous solutions. Physical and chemical properties of the Trapa natans husk activated carbon (TAC) were characterized. TAC has a large surface area of 1274 m2/g and mesoporous structure. Carboxylic and hydroxyl groups contributed to the sorption of NOR onto TAC but they were not the most important factors in the sorption process. The rates of adsorp...     

PREPARATION AND PROPERTIES OF SPAES-TiO_2 HYBRID MEMBRANES FOR DIRECT METHANOL FUEL CELL

Sulfonated poly(arylene ether sulfone)(SPAES) copolymer with degree of sulfonation of 1.0 was synthesized and characterized.A series of SPAES-TiO_2 hybrid membranes with various contents of nano-sized TiO_2 particles were prepared and characterized through sol-gel reactions.Scanning electron microscopy(SEM) images indicated the TiO_2 particles were well dispersed within polymer matrix.These composite membranes were evaluated for proton exchange membranes(PEMs) in direct methanol fuel cell(DMFC).These mem...     

Minor antifungal aromatic glycosides from the roots of Gentiana rigescens （Gentianaceae）

Two new phenolic glycosides,2,3-dihydroxybenzoic acid methyl ester 3-O-β-D-glucopyranosyl-(1-6)-β-D-glucopyranoside(1) and 2,5-dihydroxylbenzofuran 5-O-β-D-xylopyranosyl-(1-6)-O-β-D-glucopyranoside(2),were isolated as the minor chemical constituents from the roots of Gentiana rigescens,along with 15 known compounds.Their structures were elucidated by detailed spectroscopic analysis,including 1D,2D NMR and chemical method.All of these compounds were isolated for the first time from the title plant.Moreove...     

Synthesis and positive inotropic evaluation of 1-(benzylamino)-3-(4,5-di-hydro[1,2,4]trizaolo[4,3-a]quinolin-7-yloxy)propan-2-ol derivatives

In an attempt to search for more potent positive inotropic agents,a series of 1-(benzylamino)-3-(4,5-dihydro[1,2,4]trizaolo[4,3- a]quinolin-7-yloxy)propan-2-ol derivatives was synthesized in four steps using 6-hydroxy-3,4-dihydro-2(1H)-quinolinone as a starting material,and their positive inotropic activities were evaluated by measuring the coronary blood flow(CBF)and the left ventricular pressure(LVP)followed by calculating the rate of pressure development(dp/dt_(max)values)in the preparation of rat Lan...     

Synthesis and application of a hydrophobic hypercrosslinked polymeric resin for removing VOCs from humid gas stream

A hydrophobic hypercrosslinked polymeric resin LC-1 was prepared and characterized.The properties of LC-1 resin were compared with those of a commercial hypercrosslinked polymer NDA-201 resin.In addition,the dynamic adsorption of trichloroethylene(TCE)onto LC.1 under dry and humid conditions at 303 K was investigated,the result shows that LC-1possesses high hydrophobic property and can remove TCE from gas stream without effect of high humidity efficiently.