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排序方式: 共有317条查询结果,搜索用时 31 毫秒
1.
Huazhong Tang Tao Tang Kun Xu 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,55(3):365-382
In this paper, the Kinetic Flux Vector Splitting (KFVS)
scheme is extended to solving the shallow water equations with
source terms. To develop a well-balanced scheme between the source
term and the flow convection, the source term effect is accounted
in the flux evaluation across cell interfaces. This leads to a
modified gas-kinetic scheme with particular application to the
shallow water equations with bottom topography. Numerical
experiments show better resolution of the unsteady solution than
conventional finite difference method and KFVS method with little
additional cost. Moreover, some positivity properties of the
gas-kinetic scheme is established. 相似文献
2.
E. M. Afsah M. M. Abou-Elzahab M. T. Zimaity G. R. Proctor 《Monatshefte für Chemie / Chemical Monthly》1984,115(8-9):1065-1070
When 64n853265325683/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-keto-ester1 a was reacted with dimethyl acetylenedicarboxylate ring expansion occurred to give substituted cyclooctadienones.Michael reactions of the title compounds1 with unsaturated ketones gave adducts, some of which underwent further cyclization reactions. A new route to 64n853265325683/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-tetralone ring system10 via cyclization of the intermediateMichael adduct9 is described.
Michael- und Ringerweiterungsreaktionen von 6-Carboethoxy-3,5-diaryl-2-cyclohexen-1-onen
Zusammenfassung Bei der Reaktion von 64n853265325683/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-Keto-ester1 a mit Dimethyl-acetylendicarboxylat wurden unter Ringerweiterung substituierte Cyclooctadienone erhalten. DieMichael-Reaktion der Titelverbindung1 mit ungesättigten Ketonen ergab Addukte, von denen einige weitere Cyclisierungsreaktionen eingingen. Es wird ein neuer Weg zum 64n853265325683/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Tetralonsystem10 über die Cyclisierung des intermediärenMichael-Addukts9 beschrieben.相似文献
3.
64/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-(2-Arylaminoethoxy)styrenes undergo cyclization in the presence of KOH to giveN-aryl-2-benzyloxazolidines inca. 90 % yield. The structures of the products were confirmed by IR and NMR spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 340–341, February, 1994. 相似文献
4.
V. Ramamoorthy A. Ramasubbu S. Muthusubramanian S. Sivasubramanian 《Journal of inclusion phenomena and macrocyclic chemistry》1999,33(1):69-80
The nitrone is found to be included in the 64t061577226184/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-cyclodextrin cavity in two different stoichiometries viz., 1G : 1H and 1G : 2H – the existence of which is proved by physical methods. The 1G : 2H complex of the nitrone serves as a good potent dipolarophile in the 1,3-dipolar cycloaddition reactions with olefins resulting in rate acceleration and regioselection. 相似文献
5.
We investigate then64/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0"> 64/xxlarge8734.gif" alt="infin" align="MIDDLE" BORDER="0"> limit of then-vector model single-spin and pairspin correlation functions. In this limit we show that the correlation functions become those of the corresponding spherical model. 相似文献
6.
R. F. Klevtsova L. A. Glinskaya T. E. Kokina S. V. Larionov 《Journal of Structural Chemistry》2003,44(2):256-267
Single crystals of [Ni(Phen)(i64h8/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">Bu2PS2)2] (I) and [Ni(Phen)3](i64h8/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">Bu2PS2)2 (III) compounds were grown, and their structures were determined by X64h8/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">ray diffraction analysis (CAD64h8/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">4 diffractometer, MoK
64h8/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> radiation, 3336 F
hkl
, R = 0.0373 for I and 2575 F
hkl
for III). The crystals of complex I have a triclinic unit cell with the following parameters: a = 11.097(1) 64h8/xxlarge8491.gif" alt="angst" align="MIDDLE" BORDER="0">, b = 14.903(2) 64h8/xxlarge8491.gif" alt="angst" align="MIDDLE" BORDER="0">, c = 22.650(3)64h8/xxlarge8491.gif" alt="angst" align="MIDDLE" BORDER="0">; 64h8/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> = 75.18(1)°, 64h8/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> = 80.50(1)°, 64h8/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0"> = 75.07(1)°, V = 3479.2(7)64h8/xxlarge8491.gif" alt="angst" align="MIDDLE" BORDER="0">3, Z = 4, 64h8/xxlarge961.gif" alt="rgr" align="MIDDLE" BORDER="0">calc = 1.255 g/cm3, and space group
64h8/10947_2004_Article_474369_TeX2GIFIE1.gif" alt="
$$\bar P$$
" align="middle" border="0">
1; the crystals of III have a monoclinic unit cell with the following parameters: a = 19.010(3)64h8/xxlarge8491.gif" alt="angst" align="MIDDLE" BORDER="0">, b = 15.481(1) 64h8/xxlarge8491.gif" alt="angst" align="MIDDLE" BORDER="0">, c = 17.940(3)64h8/xxlarge8491.gif" alt="angst" align="MIDDLE" BORDER="0">; 64h8/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> = 97.58(1)°, V = 5233.5(12)64h8/xxlarge8491.gif" alt="angst" align="MIDDLE" BORDER="0">3, Z = 4, 64h8/xxlarge961.gif" alt="rgr" align="MIDDLE" BORDER="0">calc = 1.292 g/cm3, and space group C2/c. The structure of complex I is built from mononuclear molecules, and the structure of III, from [Ni(Phen)3]2+ complex cations and i64h8/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0"> Bu2PS2
- outer64h8/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">sphere anions. The NiN2S4 coordination polyhedra in the structure of I and NiN6 in the structure of III are distorted octahedra. Based on structural data, the interaction between the coordinated Phen molecules of complexes I, [Ni(Phen)2(i64h8/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">Bu2PS2)](i64h8/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">Bu2PS2) (II), and III is considered, as well as the packing modes of these complexes. 相似文献
7.
A. L. Rusanov G. S. Matvelashvili G. V. Kazakova M. L. Keshtov A. K. Mikitaev 《Russian Chemical Bulletin》1996,45(3):633-636
Synthesis of 4,464x432/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-bis(4-aminophenoxy)benzophenone was performed starting from chloral. Various polyimides were obtained by reactions of 4,4 64x432/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-bis(4-aminophenoxy)benzophenone with aromatic tetracarboxylic acid dianhydrides. Some of the polyimides obtained are crystalline compounds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 673–676, March, 1996. 相似文献
8.
J. Rätz 《Aequationes Mathematicae》1976,14(1-2):67-71
LetK be a ring with an identity 1 0 andM, L two unitaryK-modules. Then, for any additive mappingf:M L, the setH
f
:={ K f(x)=f(x) for allx M} forms a subring ofK, the homogeneity ring off. It is shown that, forM {0},L {0} and any subringS ofK for whichM is a freeS-module, there exists an additive mappingf:ML such thatH
f
=S. This result is applied to the four Cauchy functional equations, and it leads also to an answer to the question as to whether it is possible to introduce onM a multiplication ·:M × M M makingM into a ring but not into aK-algebra. 相似文献
9.
K. Przewlocki L. Petryka Z. Stḙgowski 《Isotopes in environmental and health studies》2013,49(9):439-444
One of the most difficult operations for control and identification in copper ore concentration process is grain classification in hydrocyclone batteries. In the paper radiotracer investigations of the classification process immediately give values of hydrocyclones parameters with higher accuracy than obtained from conventional methods. Presented paper includes the results of the investigation which was carried out in “Lubin” Copper Mine in Poland. 相似文献
10.