土壤中十四种元素的ICP-AES和ISE的碱熔直接测定

报道了应用直读型电感耦合等离子体发射光谱(ICP-AES)及离子选择电极(Ion-SelectiveElectrode,简称ISE)成功地测定土壤中十四种难测元素的方法及其精度。土壤样品经过NaOH高温熔融、用水定容后,直接在强碱性溶液中用ICP-AES测定通常较难测定的十三种元素;Se、Mo、B、As、Si、S、Pb、P、Ge、Sn、Sb、Cr、K。通过ISE亦能很好地测定F。     

Tsaokoin, a New Bicyclic Nonane from Amomum tsao-ko

Amomum tsao-ko Crevost et Lem., a zingiberaceous plant called "Caoguo" or "Tsao-ko" in Yunnan, China, is a Chinese traditional medicinal herb for treatment of stomach illness and a common spice as well. Some chemical researches on the constituents of its essential oil1, 2 and antioxidative phenolic compounds3 have been reported. In this paper, we describe the structure of an unusual bicyclo[4,3,0]nonane derivative, tsaokoin 1, which was isolated from the chloroform extract of the fruits of t…     

Synthesis, Characterization, Spectroscopic and Electro-chemical Properties of New Mono- and Binuclear Copper(I) Complexes with Substituted 2,2''''-Bipyridine

Introduction Copper(I) complexes have received much attention for their being less expensive and environmentally friendly, various coordination geometry, rich photo-chemical and photophysical properties.1-7 It is well known that copper complexes with diimine (2,2'-bipy- ridine, 1,10-phenanthroline and their substituted deriva-tives designated as diimine) generally exhibit low en-ergy metal-to-ligand charge-transfer (MLCT) states lo-cated in the regions of 350650 nm (e ≈ 103—104 dm3昺ol-1昪…     

铂络合物的反相离子对色谱

在反相离子对色谱中,研究了四种离子对试剂对铂络合物保留值的影响。用流动相中离子-偶极作用物和铂络合物的结构说明了保留机理。用NaCl作内标测定了顺式-二氨-1,1-环丁二羧酸铂(Ⅱ)(碳铂)和顺式二氯二氨合铂(Ⅱ)(顺铂)样品,七次配样测定得到满意的回收率,相对标准偏差分别为0.7%和0.5%,检出限为75ng/ml和0.23μg/ml。     

Facile shape and size-controlled growth of uniform magnetite and hematite nanocrystals with tunable properties

Monodispersed magnetite Fe3O4 and hematite α-Fe2O3 nanocrystals have been grown in co-solvents of alcohol and water. Either the shape or the size of the nanocrystals could be easily controlled. Both the phases and nanostructures have been characterized by powder X-ray diffraction patterns and electron microscopy. The magnetic and catalytic properties of these products were investigated and compared with each other. The obtained results clearly demonstrate that these iron oxide nanocrystals are soft ferromag...     

Synthesis,Bioactivity and Crystal Structure Analysis of Novel Benzo[d]isothiazol-3（2H）-ones

Two compounds,3-oxo-N-o-tolylbenzo[d]isothiazole-2(3H)-carboxamide (1) and N-(2-methoxyphenyl)-3-oxobenzo[d]isothiazole-2(3H)-carboxamide (2),were synthesized from the initial compound benzo[d]isothiazol-3(2H)-one (BIT) and characterized by 1 H NMR,IR and elemental analysis,respectively.The single crystals of compounds 1 and 2 were obtained and determined by X-ray diffraction analysis.The preliminary results of biological activity experiment show that some of the title compounds exhibited a favorable antimicrobial activity.     

Oxygen removal from raw silicon powder by the HF‐ethanol solution etching

Silicon powder is vulnerable to oxidation due to its high surface activity. The as‐prepared Si powder is characterized by X‐ray photoelectron spectroscopy spectra coupled with an oxygen nitrogen analyzer, revealing that oxygen impurities mainly consist of Si oxides but with a small amount of free oxygen. The stable oxide films can deteriorate the properties of sintered materials since they cannot be removed during sintering process. The cleaning of these oxides by a single‐HF solution is not straightforward and efficient due to the large surface tension. To remove the oxygen, a more efficient way with the addition of ethanol to a HF solution has been proposed. The addition of a moderate percent of ethanol can decrease the water contact angle and then improve the cleaning efficiency. Importantly, the resulting Si powder possesses good dispersity, uniformity and fluidity. However, excess hydrofluoric acid suppresses oxide removal. Copyright © 2012 John Wiley & Sons, Ltd.     

ZnO-Fe3O4 composite prepared by sol-gel method with H2 deoxidation

Fe doped ZnO powder samples (Fe/Zn=0.05 and 0.1) were prepared by sol-gel method with H₂ deoxidation at 450 ^°C for several hours or just heated in air at the same temperature. It was showed by vibrating sample magnetometer (VSM) that samples heat treated in H₂ could show strong ferromagnetism at room temperature while samples treated in air only show very weak magnetism. XRD using Co kα X-ray revealed that the samples heated in H₂ were not pure phase but like a granular system and the magnetism mainly results from Fe₃O₄ in samples while samples heated in air showed pure ZnO phase. Our work indicated that H₂ deoxidation treatment may be an effective technique to fabricate such magnetic semiconductor-like materials with Curie temperature higher than room temperature.     

Two New Xanthones from Polygala crotalarioides

Two new xanthones, 1,6,8-trihydroxy-2,3-methylenedioxyxanthone 1 and 1,4-dihydroxy-6, 7-methylenedioxyxanthone 2, were isolated from the roots of Polygala crotalarioides. Their structures were elucidated by spectroscopic and chemical methods.     

幂群与它的生成群

设г是G上的幂群,即以G的非空子集为元素,在G的子集的运算之下所成的群.P_1,P_2是这样的两个性质 P_1:对任意g∈G,存g∈G,存在A∈г,使得g∈A. P_2:对任意A,B∈г,如果A≠B,则A∩B=φ. 本文得出了群G上的幂群г分别具有性质P_1或P_2的充要条件.