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951.
Structure and Bonding in CE5− (E=Al–Tl) Clusters: Planar Tetracoordinate Carbon versus Pentacoordinate Carbon 下载免费PDF全文
Estefanía Ravell Said Jalife Jorge Barroso Mesías Orozco‐Ic Gerardo Hernández‐Juárez Dr. Filiberto Ortiz‐Chi Dr. Sudip Pan Dr. José Luis Cabellos Prof. Gabriel Merino 《化学:亚洲杂志》2018,13(11):1467-1473
The structure, bonding, and stability of clusters with the empirical formula CE5? (E=Al–Tl) have been analyzed by means of high‐level computations. The results indicate that, whereas aluminum and gallium clusters have C2v structures with a planar tetracoordinate carbon (ptC), their heavier homologues prefer three‐dimensional C4v forms with a pentacoordinate carbon center over the ptC one. The reason for such a preference is a delicate balance between the interaction energy of the fifth E atom with CE4 and the distortion energy. Moreover, bonding analysis shows that the ptC systems can be better described as CE4?, with 17‐valence electrons interacting with E. The ptC core in these systems exhibits double aromatic (both σ and π) behavior, but the σ contribution is dominating. 相似文献
952.
The reaction of Ag2SO4 and bpp (bpp = 1,3‐bis(4‐pyridyl)propane) in H2O afforded the complex [Ag2(bpp)2(SO4) · 6.5H2O·CH3OH]n, 1. The IR and TGA have been recorded and the structure has been determined. Crystal data for 1: Space group C2/c, a = 17.885(4), b = 25.230(6), c = 8.832(2) Å, β = 105.437(4)°. V = 3841(1) Å3, Z = 8 with final residuals R1 = 0.0710 and wR2 = 0.1620. The complex shows a three‐dimensional supramoleclar structure constructed with two‐dimensional infinite [Ag2(bpp)2]n sheetlike layers pillared by Ag‐Ag interactions and Ag····O (SO4) interactions in the solid state. 相似文献
953.
954.
Ju Myung Kim 《Journal of Mathematical Analysis and Applications》2006,321(2):569-575
It is shown that for the separable dual X∗ of a Banach space X if X∗ has the weak approximation property, then X has the metric quasi approximation property. Using this it is shown that for the separable dual X∗ of a Banach space X the quasi approximation property and metric quasi approximation property are inherited from X∗ to X and for a separable and reflexive Banach space X, X having the weak approximation property, bounded weak approximation property, quasi approximation property, metric weak approximation property, and metric quasi approximation property are equivalent. Also it is shown that the weak approximation property, bounded weak approximation property, and quasi approximation property are not inherited from a Banach space X to X∗. 相似文献
955.
Yun MY Kim SB Park S Han CJ Han YH Yoon SH Kim SH Kim CM Choi DW Cho MH Park GH Lee KH 《Experimental & molecular medicine》2007,39(4):508-513
Failure of mitotic checkpoint machinery leads to the chromosomal missegregation and nuclear endoreduplication, thereby driving the emergence of aneuploidy and tetraploidy population. Although abnormal nuclear ploidy and the resulting impairment of mitotic checkpoint function are typical physiological event leading to human hepatocellular carcinoma, any mutational change of mitotic checkpoint regulators has not yet been discovered. Therefore, we investigated the mutation of p31(comet), a recently identified mitotic checkpoint regulator, in human hepatocellular carcinoma. Of 51 human hepatocellular carcinoma tissue and 6 cell lines tested, five samples exhibited nucleotide sequence variations dispersed on four sites within the entire coding sequence. Among these sites with sequence substitutions, three were found to be missense mutation accompanied with amino acid change but one was a silent mutation. Of these sequence substitutions, two were present in both tumor and non-tumor liver tissues, suggesting the possibility of polymorphism. The present findings indicate that p31(comet) does not have an impact on the formation of aneuploidy and tetraploidy found in human hepatocellular carcinoma. 相似文献
956.
957.
IntroductionSnake-cageresin,alsoca1ledsnake-cagepolyelectrolyte['],isaspecialkindofamphotericresin.ItwasfirstinvestigatedbyHatchM.J.etal.in1957[z].Thetypicalandusefulsnake-cageresinisRetardation11A-8(l1A-8inthecon-text)manufacturedbyDowChemicalCoI,TD.Itissynthesizedbypolymerizingacrylicacidinsidethenetworkofastrongbasicanionexchangeresinwith8%crosslinking.Thus,theresinconsistsofacrosslinkedpolymermatrix,cage,andalinearpolymer,socalledsnake,whichisphysicallytrappedinsidethecage.Thecagepol… 相似文献
958.
A New Megastigmane Glucoside and Three New Flavonoid Glycosides from Spiraea prunifolia var. simpliciflora 下载免费PDF全文
A new megastigmane glucoside, simplicifloranoside ( 1 ), and three new flavonol glycosides, prunifolianosides A–C ( 2 – 4 , resp.), were isolated from the aerial parts of Spiraea prunifolia var. simpliciflora. In addition, fifteen known compounds, including five phenolic acids, three lignans, four flavonoids, one eugenol glycoside, and two alkyl‐primeverosides, were also identified. Their structures were elucidated on the basis of detailed spectroscopic analyses and acid hydrolysis. 相似文献
959.
LiMingWEI QingYuOU JuBaiLI 《中国化学快报》2004,15(9):1127-1130
The sol-gel technology is applied for the preparation of solid-phase microextraction (SPME) fiber. The fiber demonstrates high thermal stability, efficient extraction rate and the selectivity for non-polar or low-polar analytes. Efficient SPME-GC-FID analyses of benzenetoluene-ethylbenzene-xylenes (BTEXs) and low-polar halocarbon were achieved by the sol-gel coated DSDA-DDBT-TiO2 fiber. Some parameters of the SPME fiber for the determination of halocarbon in aqueous sample were investigated. 相似文献
960.