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991.
Comparison of Models Used for UV Index Calculations 总被引:1,自引:1,他引:1
Peter Koepke Alkiviadis Bais Dimitrios Balis Michael Buchwitz Hugo De Backer Xavier de Cabo Pierre Eckert Paul Eriksen Didier Gillotay Anu Heikkilä Tapani Koskela Bozena Lapeta Zenobia Litynska Jeronimo Lorente Bernhard Mayer Anne Renaud Ansgar Ruggaber Günther Schauberger Gunther Seckmeyer Peter Seifert Alois Schmalwieser Harry Schwander Karel Vanicek Mark Weber 《Photochemistry and photobiology》1998,67(6):657-662
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A model to study the local structure and geometry of condensed matter was applied to the lattice dilatation of Cu if a + is implanted interstitially. The model system consists of a finite cluster of atoms embedded in the spherically symmetric part of the potential of the rest of the material.The calculations were calibrated with crystalline Cu using a cluster of 6 atoms and 0, 6 or a practical infinite number of layers around this central cluster. It is found that 6 layers are enough to deseribe the boundary conditions that the material imposes to the selected central cluster.Afterwards it was applied to a cluster of a central + and 6 octahedrally disposed Cu. The equilibrium geometries, electronic configurations, electronic densities of states are presented and compared with SR. 相似文献
996.
Thin‐Film Transformation of NH4PbI3 to CH3NH3PbI3 Perovskite: A Methylamine‐Induced Conversion–Healing Process
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Yingxia Zong Dr. Yuanyuan Zhou Dr. Minggang Ju Dr. Hector F. Garces Dr. Amanda R. Krause Fuxiang Ji Dr. Guanglei Cui Prof. Xiao Cheng Zeng Prof. Nitin P. Padture Dr. Shuping Pang 《Angewandte Chemie (International ed. in English)》2016,55(47):14723-14727
Methylamine‐induced thin‐film transformation at room‐temperature is discovered, where a porous, rough, polycrystalline NH4PbI3 non‐perovskite thin film converts stepwise into a dense, ultrasmooth, textured CH3NH3PbI3 perovskite thin film. Owing to the beneficial phase/structural development of the thin film, its photovoltaic properties undergo dramatic enhancement during this NH4PbI3‐to‐CH3NH3PbI3 transformation process. The chemical origins of this transformation are studied at various length scales. 相似文献
997.
Anatolii?Grinshpan Dmitry?S.?Kaliuzhnyi-VerbovetskyiEmail author Victor?Vinnikov Hugo?J.?Woerdeman 《Mathematische Zeitschrift》2016,282(1-2):25-42
We show that a polynomial p with no zeros on the closure of a matrix unit polyball, a.k.a. a cartesian product of Cartan domains of type I, and such that \(p(0)=1\), admits a strictly contractive determinantal representation, i.e., \(p=\det (I-KZ_n)\), where \(n=(n_1,\ldots ,n_k)\) is a k-tuple of nonnegative integers, \(Z_n=\bigoplus _{r=1}^k(Z^{(r)}\otimes I_{n_r})\), \(Z^{(r)}=[z^{(r)}_{ij}]\) are complex matrices, p is a polynomial in the matrix entries \(z^{(r)}_{ij}\), and K is a strictly contractive matrix. This result is obtained via a noncommutative lifting and a theorem on the singularities of minimal noncommutative structured system realizations. 相似文献
998.
Fürstner A Martin R Krause H Seidel G Goddard R Lehmann CW 《Journal of the American Chemical Society》2008,130(27):8773-8787
A series of unprecedented organoiron complexes of the formal oxidation states -2, 0, +1, +2, and +3 is presented, which are largely devoid of stabilizing ligands and, in part, also electronically unsaturated (14-, 16-, 17- and 18-electron counts). Specifically, it is shown that nucleophiles unable to undergo beta-hydride elimination, such as MeLi, PhLi, or PhMgBr, rapidly reduce Fe(3+) to Fe(2+) and then exhaustively alkylate the metal center. The resulting homoleptic organoferrate complexes [(Me 4Fe)(MeLi)][Li(OEt 2)] 2 ( 3) and [Ph 4Fe][Li(Et 2O) 2][Li(1,4-dioxane)] ( 5) could be characterized by X-ray crystal structure analysis. However, these exceptionally sensitive compounds turned out to be only moderately nucleophilic, transferring their organic ligands to activated electrophiles only, while being unable to alkylate (hetero)aryl halides unless they are very electron deficient. In striking contrast, Grignard reagents bearing alkyl residues amenable to beta-hydride elimination reduce FeX n ( n = 2, 3) to clusters of the formal composition [Fe(MgX) 2] n . The behavior of these intermetallic species can be emulated by structurally well-defined lithium ferrate complexes of the type [Fe(C 2H 4) 4][Li(tmeda)] 2 ( 8), [Fe(cod) 2][Li(dme)] 2 ( 9), [CpFe(C 2H 4) 2][Li(tmeda)] ( 7), [CpFe(cod)][Li(dme)] ( 11), or [Cp*Fe(C 2H 4) 2][Li(tmeda)] ( 14). Such electron-rich complexes, which are distinguished by short intermetallic Fe-Li bonds, were shown to react with aryl chlorides and allyl halides; the structures and reactivity patterns of the resulting organoiron compounds provide first insights into the elementary steps of low valent iron-catalyzed cross coupling reactions of aryl, alkyl, allyl, benzyl, and propargyl halides with organomagnesium reagents. However, the acquired data suggest that such C-C bond formations can occur, a priori, along different catalytic cycles shuttling between metal centers of the formal oxidation states Fe(+1)/Fe(+3), Fe(0)/Fe(+2), and Fe(-2)/Fe(0). Since these different manifolds are likely interconnected, an unambiguous decision as to which redox cycle dominates in solution remains difficult, even though iron complexes of the lowest accessible formal oxidation states promote the reactions most effectively. 相似文献
999.
Cristiano R Gallardo H Bortoluzzi AJ Bechtold IH Campos CE Longo RL 《Chemical communications (Cambridge, England)》2008,(41):5134-5136
The synthesis and structural, thermal, optical and theoretical characterization of new tris[1,2,4]triazolo[1,3,5]triazines were performed to support their application as liquid crystals and advanced materials. 相似文献
1000.
Hutton BW MacIntosh F Ellis D Herisse F Macgregor SA McKay D Petrie-Armstrong V Rosair GM Perekalin DS Tricas H Welch AJ 《Chemical communications (Cambridge, England)》2008,(42):5345-5347
The reduction and subsequent oxidation of meta-carboranes containing bulky groups attached to the cage C atoms affords sterically-crowded ortho-carboranes with unprecedentedly long C-C connectivities. 相似文献