几种常见水果的微量元素分析

运用原子吸收分光光度法测定了几种常见水果中部分微量元素含量。其中榴莲的Mg、Zn、Cu、K含量位于四种水果之首。美国提子中Ca含量最高，芒果中Fe含量最高。以上差别具有统计学意义。六种元素的回收率为90％-106．5％。连续6次测定样品，变异系数(CV)为0．96％。     

二氧化碳多相催化加氢的新进展

就近年来关于ＣＯ２活化、几个重要的ＣＯ２多相催化加氢反应及廉价氢的供给的研究进展进行综述。参考文献３４篇。     

Metrological role of neutron activation analysis. IB. Inherent characteristics of relative INAA as a primary ratio method of measurement

This is the second part of a paper which deals with the advantages and disadvantages of relative instrumental neutron activation analysis concerning traceability and uncertainty, and the current scope and possible future extensions of neutron activation analysis as a primary ratio method. The first part of this paper has been published in this Journal [1]. Received: 19 March 2001 Accepted: 2 October 2001     

A concise synthesis of nornitidine via nickel- or palladium-catalyzed annulation

A concise method to synthesize benzo[c]phenanthridine alkaloid, nornitidine, was developed utilizing nickel- or palladium-catalyzed iminoannulation of an internal alkyne. The advantages of this strategy included readily available starting materials, inexpensive reagents, short reaction steps, and good yields.     

尿中肌酐的流动注射分析

本文提出了一种简便快速的尿中肌酐的测定方法。采用空气整段间隔试样带的流动注射分析体系,在非化学反应平衡的条件下测定,尿样不经手工稀释可直接用于测定。测样频率每小时为90次,相对标准偏差为1.5%。     

Synthesis and biological evaluation of 3-{[4-(4-[18F]fluorophenyl)methyl] piperazin-1-yl}-methyl-1H-pyrrolo[2,3-b]pyridine for in vivo studies of dopamine D4 receptor

The compound 3-{[4-(4-[¹⁸F]fluorophenyl)methyl]piperazin-1-yl}-methyl-1H-pyrrolo[2,3-b]pyridine ([¹⁸F]3), which is an analogue of L-745,870 binding D₄ This revised version was published online in July 2006 with corrections to the Cover Date.     

稀土在鼠肝中的物种分布

采用 ICP-MS、微量蛋白层析分离技术 ,研究了长时间、低剂量混合稀土及短时间、高剂量硝酸镧分别对大鼠及小鼠作用后 ,稀土在鼠肝中的代谢累积及其物种分布 .结果表明 ,鼠肝中各稀土含量随给药剂量的增加而增大 ,其累积速度大小顺序为 La>Ce>Nd>Pr;经柱层析分离未得到与稀土特异结合的鼠肝蛋白 ;稀土可与多种鼠肝蛋白 (包括多种重要的酶 )结合 ,在一定条件下 ,稀土与其结合蛋白可发生解离     

A new C21-steroidal glycoside from Cynanchum stauntonii

A new C21-steroidal glycoside with two known compounds were isolated from the root of Cynanchum Stauntonii.Based on thespectral analysis,including MS,1H NMR,13C NMR,DEPT,1H-1H COSY,13C-1H COSY,HMQC and HMBC,their chemicalstructures were determinated as glaucogenin-C 3-O-a-L-cymaropyranosyl-(1→4)-b-D-digitoxopyranosyl-(1→4)-β-D-canaropyranoside(1),stigmasterol(2)and ursolic acid(3).     

INAA determination of major and trace elements in loess,paleosol and precipitation layers in a pleistocene Loess Section,China

Instrumental neutron activation analysis was used for the determination of 31 major and trace elements in 32 samples from the Xinji Loess Section, Shaanxi Province, China. Interferences, including those from uranium fission products, were evaluated and corrections applied where necessary. The 39.7-meter deep section comprises of Lishi Loess of the middle Pleistocene (Q₂) and Malan Loess of the late Pleistocene (Q₃). The section is characterized by the presence of 5 layers of paleosol, and each paleosol is underlain by a precipitation layer. When the elemental abundances are converted to a carbonate-free basis, there is little compositional difference among the carbonate-free fractions of loess, paleosol and precipitation layers. This indicates that dissolution of carbonate minerals by downward-moving surface water was an important process in paleosol formation while other minerals were not severely weathered and elemental fractionation was minimal. The parent materials of the paleosol and precipitation layers closely resemble the loess layers in their elemental abundances, which suggests that all layers in the section have a compositionally similar source.     

A novel trilinear decomposition algorithm： Three-dimension non-negative matrix factorization

Non-negative matrix factorization(NMF)is a technique for dimensionality reduction by placing non-negativity constraints onthe matrix.Based on the PARAFAC model,NMF was extended for three-dimension data decomposition.The three-dimension non-negative matrix factorization(NMF3)algorithm,which was concise and easy to implement,was given in this paper.The NMF3algorithm implementation was based on elements but not on vectors.It could decompose a data array directly without unfolding,which was not similar to that the traditional algorithms do.It has been applied to the simulated data array decomposition andobtained reasonable results.It showed that NMF3 could be introduced for curve resolution in chemometrics.