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排序方式: 共有619条查询结果,搜索用时 109 毫秒
1.
Bucataru Ioan Constantinescu Oana Creţu Georgeta 《Annals of Global Analysis and Geometry》2022,62(4):815-827
Annals of Global Analysis and Geometry - We prove that in a Finsler manifold with vanishing $$\chi $$ -curvature (in particular with constant flag curvature) some non-Riemannian geometric... 相似文献
2.
D. Andrae U. Häußermann M. Dolg H. Stoll H. Preuß 《Theoretical chemistry accounts》1990,77(2):123-141
Summary Nonrelativistic and quasirelativisticab initio pseudopotentials substituting the Mup>(Z–28)+up>-core orbitals of the second row transition elements and the Mup>(Z–60)+up>-core orbitals of the third row transition elements, respectively, and optimized (8s7p6d)/[6s5p3d]-GTO valence basis sets for use in molecular calculations have been generated. Additionally, corresponding spin-orbit operators have also been derived. Atomic excitation and ionization energies from numerical HF as well as from SCF pseudopotential calculations using the derived basis sets differ in most cases by less than 0.1 eV from corresponding numerical all-electron results. Spin-orbit splittings for lowlying states are in reasonable agreement with corresponding all-electron Dirac-Fock (DF) results. 相似文献
3.
Yu. A. Simonov N. V. Gérbéléu P. N. Bourosh V. B. Arion A. D. Garnovskii A. N. Sobolev V. A. Alekseenko 《Journal of Structural Chemistry》1990,31(2):365-369
Institute for Applied Physics, Academy of Sciences of the Moldavian SSR. Institute of Chemistry, Academy of Sciences of the Moldavian SSR. Nat. Research Institute for Physics and Organic Chemistry, Rostov State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 2, pp. 199–202, 1990. 相似文献
4.
Tomcík P Jencusová P Krajcíková M Bustin D Brescher R 《Analytical and bioanalytical chemistry》2005,383(5):864-868
An interdigitated microelectrode array (IDA) was applied to the determination of formaldehyde released from textiles produced
in industry. The proposed method is based on formaldehyde reaction with hypobromite which is formed in weakly basic media
by control current electrooxidation of bromide on the generator segment of the IDA array. The unreacted hypobromite diffuses
through the gap between individually polarisable IDA segments and it is amperometrically detected on the collector segment
of the IDA. The efficiency of this nonconvective transfer process in the absence of formaldehyde was substantially higher
(78%) in comparison with that when using the rotating ring disc electrode. The influence of the added formaldehyde on the
transfer process can be utilised to develop a simple and sensitive analytical procedure for formaldehyde detection with a
detection limit of 4×10up>−6up> mol dmup>−3up>. 相似文献
5.
Păcurariu C. Lazău R. I. Lazău I. Stoleriu Ş. 《Journal of Thermal Analysis and Calorimetry》2007,88(3):641-645
A kinetic study of the crystallization processes was performed for some decorative ceramic glazes in the PbO-SiOub>2ub>-Naub>2ub>O-Kub>2ub>O-CaO(BaO)-Alub>2ub>Oub>3ub>-Bub>2ub>Oub>3ub> system with addition of 10% TiOub>2ub> and ZnO. The crystallization kinetics has been studied in non-isothermal conditions using DTA technique. The apparent activation
energies of the crystallization processes were calculated using the Kissinger method. The main crystalline phase, which provides
the decorative effect, is rutile. This has been identified by X-ray diffraction and it is clearly visible in the optical microscopy
images taken in transmitted light, as needle-like or even prismatic crystals arranged in radial-fibrous aggregates. 相似文献
6.
N. V. Gérbéléu V. B. Arion Yu. A. Simonov V. E. Zavodnik K. I. Turté S. S. Stavrov A. A. Pasynskii O. G. Ellert D. I. Grédinaru M. S. Byrke 《Theoretical and Experimental Chemistry》1991,27(3):327-332
Sodium acetylacetonate reacts with S-metliylisothiosemicarbazidium nitrate and Fe(NOub>3ub>)ub>3ub> · 9Hub>2ub>O in ethanol to make [Fe(HL)NO]NOub>3ub>, in which Hub>3ub>L is bis(S-methyl-isothiosemicarbazone)-2,4-puntandione. The [Fe(HL)NO]up>+up> cation has a square pyramidal structure with the HLup>2-up> arranged around the central ion in the basal plane and the nitrogen atom of the NO group in the apical position, with the iron atom diverging from the plane of the base of the pyramid by 0.477 Å. The FeN0 moiety has a linear structure (u/xxlarge8736.gif" alt="ang" align="BASELINE" BORDER="0">FeNO = l72.7°). XRD, IR, and Mössbauer spectroscopy have been combined with calculations on the electronic structure to demonstrate that the Fe-NO bond is covalent.Chemical Institute, Academy of Sciences of Moldavian SSR. Applied Physics Institute, Academy of Sciences of the Moldavian SSR. Kishinev. Institute of Crystallography, Academy of Sciences of the USSR. Kurnakov Institute for General and Inorganic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No, 3, pp. 376–381, May–June, 1991. Original article submitted February 18, 1991. 相似文献
7.
8.
M. A. Aramendia V. Boráu C. Jimenez J. M. Marinas 《Reaction Kinetics and Catalysis Letters》1981,18(3-4):335-339
The synthesis and physicochemical properties of new metallic systems obtained by supporting Pd on colloidal AlPOub>4ub>, AlPOub>4ub>–SiOub>2ub> and AlPOub>4ub>--Alub>2ub>Oub>3ub> to be used as reduction catalysts are reported. The catalytic activity of the above systems in the transfer reduction of nitrobenzene using cyclohexene as hydrogen donor has been measured.
uote>ucy" align="BASELINE" BORDER="0"> , ucy" align="MIDDLE" BORDER="0"> Pd AlPOub>4ub>, AlPOub>4ub>SiOub>2ub> AlPOub>4ub>-Alub>2ub>Oub>3ub> ucy" align="MIDDLE" BORDER="0"> . , ucy" align="MIDDLE" BORDER="0"> . uote> 相似文献
9.
Oren?Regev Jean-Fran?ois?Gohy Bas?G.?G.?Lohmeijer Sunil?K.?Varshney Dominique?H.?W.?Hubert Peter?M.?Frederik Ulrich?S.?SchubertEmail author 《Colloid and polymer science》2004,282(4):407-411
Metallo-supramolecular diblock copolymers consisting of a polystyrene (PS) block connected to a poly(ethylene oxide) (PEO) block by a bis(terpyridine)ruthenium complex (PSub>20ub>-[Ru]-PEOub>
y
ub>) were used to prepare aqueous micelles. The length of the PS block was kept constant, while two PEOs of different molecular weight were used. The resulting hydrated micelles and aggregates were characterized by a combination of cryogenic transmission electron microscopy (cryo-TEM) and dynamic light scattering measurements. The results were compared to those obtained for a covalent counterpart (PSub>22ub>-b-PEOub>70ub>). Cryogenic transmission electron microscopy allowed visualization of the PS core of the micelles. Moreover, the aggregates result from clustering of individual micelles. 相似文献
10.
N. V. Gérbéléu K. M. Indrichan V. B. Arion 《Theoretical and Experimental Chemistry》1991,27(2):187-192
The mass spectra of the coordination compounds of nickel(II) with the bis-S-substituted thiosemicarbazones of 2,4-pentanedione (Rub>2ub>Hub>2ub>L) with the general formula [NiRub>2ub>HL]X and of 3-oxo-2,4-pentanedione (Hub>2ub>Rub>2ub>LO) with the general formula NiRub>2ub>LO were studied. A distinguishing feature of the mass spectra of [NiRub>2ub>HL]X is the absence of molecular ion peaks. The initial point of fragmentation is the [M - HX] ions. The strongest lines in spectra of NiRub>2ub>LO are those due to the elimination of R and R-H. At the first stage the fragmentation of all the investigated compounds takes place mainly through only one of the thiosemicarbazide residues. At the second stage the 2,4-pentanedione (3-oxo-2,4-pentanedione) residue is eliminated, after which the remaining thiosemicarbazide part dissociates. A significant part of the fragmentation paths was confirmed by the peaks of the metastable ions and also by the mass spectra of the deuterated analogs.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kishinev. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No. 2, 205–211, March–April, 1991. Original article submitted August 19, 1986. 相似文献