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81.
82.
Abrams GS Adolphsen CE Aleksan R Alexander JP Averill D Ballam J Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D de Boer W Bonvicini G Boyarski A Brabson B Breakstone A Brom JM Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan DE Dorfan JM Drell PS Drewer DC Elia R Fay J Feldman GJ Fernandes D Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Grindhammer G 《Physical review letters》1989,63(15):1558-1561
83.
Abrams GS Adolphsen CE Averill D Ballam J Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D Bonvicini G Boyarski A Brabson B Breakstone A Brom JM Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan DE Dorfan JM Drewer DC Elia R Feldman GJ Fernandes D Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Grindhammer G Grosse-Wiesmann P Hanson G Harr R Harral B Harris FA 《Physical review letters》1989,63(20):2173-2176
84.
Abrams GS Adolphsen CE Aleksan R Alexander JP Allen MA Atwood WB Averill D Ballam J Bambade P Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D de Boer W Bonvicini G Boyarski A Brabson B Breakstone A Breidenbach M Brom JM Brown JL Brown KL Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Clendenin J Cords D Coupal DP Dauncey P Dean NR DeStaebler HC Dorfan DE Dorfan JM Drell PS Drewer DC Dydak F Ecklund S Elia R Erickson RA Fay J Feldman GJ Fernandes D Field RC Fieguth TH 《Physical review letters》1989,63(7):724-727
85.
This paper describes a computer modelling study of rare earth doping in the mixed metal fluorides LiCaAlF 6 , LiSrAlF 6 and LiYF 4 . All these materials have potential technological applications, providing the motivation to improve understanding of their defect chemistry; in particular the energetics of doping and the sites occupied by dopant ions. Computer modelling is used to calculate the effect of rare earth dopant concentration on the structure of LiYF 4 , and to predict the sites occupied by rare earth dopants and the corresponding form of charge compensation, in LiCaAlF 6 and LiSrAlF 6 . 相似文献
86.
Na Xu Xu Dong Xu Li Yan Ma Jing Quan Yuan Jian Hua Miao Yan Cheng Jun Shan Yang 《中国化学快报》2010,21(6):696-698
<正>A new homoflavonoid was isolated from the seed of Caesalpinia minax Hance.On the basis of spectral evidences,its structure was established and named as minaxin. 相似文献
87.
A series of 3,6-dichloro-1H-pyridazin-4-ones have been prepared via the cycloaddition of 3,6-dichlorotetrazine with alkynylboronates, and their employment as useful synthetic intermediates was highlighted through a selection of highly regioselective C-O, C-S and C-C bond forming reactions. 相似文献
88.
The adsorption of methanol on basic zeolites X and Y was investigated with both atomistic and quantum chemical methods. The Monte Carlo docking method was used to localize preferred adsorption sites within the framework. Sites were found adjacent to the interstitial alkali cations in the sites SI, SII, and SIII. We investigated the influence on adsorption behavior of all possible interstitial alkali metal cations, i.e., Li(+), Na(+), K(+), Rb(+), and Cs(+), and in the case of site SII also the influence of varying the Si/Al ratio and distribution. Clusters were cut from the periodic framework in a way that the topological character of the different sites was preserved. DFT calculations yielded geometries and energetic data, which are analyzed with respect to the nature of the cation and to the Si/Al ratio. Adsorption of the methanol molecule is influenced mainly by the identity of the alkali metal cation. Other factors, including Si/Al ratio, are of secondary importance, though there is evidence of weak hydrogen bonding between methanol hydrogen and framework. Cation positions are displaced only slightly by interaction with methanol, although somewhat more at the SIII sites than the SII. We propose that the SIII sites may be a more likely location for methanol activation, particularly in the reaction with toluene, which favors the SII site. 相似文献
89.
ShiMingDENG YouXingZHAO YuQingLIU JunZHOU 《中国化学快报》2005,16(5):623-624
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. 相似文献
90.
The phytochemical investigation on the ethanolic extracts of the barks of Taxus yunnanensis (Taxaceae) led to the isolation of two new neo-lignans, named taxuyunins A (1) and B (2), along with the known diterpenolignan, brevitaxin (3). Their structures were elucidated on the basis of spectroscopic and chemical evidences. Compound 1 is a neo-lignan xyloside while compound 2 belongs to the rare neo-lignan possessing a ramified C3 side chain. 相似文献