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排序方式: 共有385条查询结果,搜索用时 15 毫秒
1.
T. M. Varlamova G. V. Gerasimova S. P. Mushtakova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(10):1671-1675
The solubility diagrams of the potassium iodide-water-N,N-dimethylformamide (DMFA) and iodine-iodide-water-N,N-dimethylformamide systems were studied at 25°C by the method of sections. The systems are characterized by three-phase equilibria of the peritonic and eutonic types, respectively. Potassium iodide in the I2-KI-/H2O-DMFA (95: 5 wt %)/ system was found to salt in crystalline iodine. The selected composition of the H2O-DMFA mixed solvent possessed a higher iodine-solving ability compared with pure mixture components. 相似文献
2.
3.
Conditions for the precipitation of phosphates from solutions of titanium(IV) sulfate containing iron(III) were studied. The precipitation of components and the mechanism of the phase formation in the system under study were considered in relation to the TiO2 : Fe2O3 ratio in the starting solution. 相似文献
4.
I. G. Abramov A. V. Smirnov L. S. Kalandadze N. P. Gerasimova N. A. Nozhnin V. N. Sakharov 《Chemistry of Heterocyclic Compounds》2005,41(2):238-240
New 3-aryl-substituted [1,2,4]triazolo][3,4-b][1,3]benzothiazole-6,7-dicarbonitriles have been synthesized by successive interaction of 5-aryl-4H-triazole-2-thiols with 4-bromo-5-nitrophthalonitrile in the presence of K2CO3 initially at the bromine atoms and then at the nitro group.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, 270–272, February, 2005. 相似文献
5.
The rate of cyclization of pentafluoro- (1) and 4-Cl-2,3,5,6-tetrafluoro-2-NHY-diphenyl ethers (2a, Y=Ac;2b, Y=H;2c, Y=Me) to form phenoxazines on refluxing in DMF increases with an increase in the nucleophilicity of the amino group. The cyclization of the N-acetyl derivative2a is followed by the Smiles rearrangement, whereas the transformation of ethers2b andc, containing free amino and N-methylamino groups, respectively, includes mainly an attack on the amino group at theortho-position of the fluorinated ring. In the case of ether2c, introduction of K2CO3 into the reaction mixture results in cyclization with the Smiles rearrangement.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1101–1105, June, 1993. 相似文献
6.
L. N. Sycheva G. F. Gerasimova M. S. Gaisinovich A. N. Ketov 《Reaction Kinetics and Catalysis Letters》1977,7(2):127-132
It has been shown that in the interaction of zinc oxide and phosgene, the most active are the samples having oxygen vacancies. A mechanism for this process is suggested.
, , . .相似文献
7.
In Computerized Tomography (CT), an image must be recovered from its sampled projections in the form of values of the Radon transform. In this work a method of recovering the image is based on the properties of the raised-cosine wavelet. This wavelet has a closed form which allows for certain precomputations and avoids convolution. The rate of convergence of the resulting algorithm to the image density function is found under suitable hypotheses. This algorithm is then tested on the standard Shepp–Logan 相似文献
8.
Tommy Dreyfus† Theodore Eisenberg† 《International Journal of Mathematical Education in Science & Technology》2013,44(3):489-497
There is a definite movement to remove many of the topics concerning polynomials from the school curriculum. The purpose of this paper is to point out why this movement is misguided and should be reversed. 相似文献
9.
Tatiana G. Gerasimova 《Linear algebra and its applications》2012,436(9):3777-3783
We give several criteria of unitary similarity of a normal matrix A and any matrix B in terms of the Frobenius and spectral norms, characteristic polynomials, and traces of matrices. 相似文献
10.
By the method of neutron diffraction, the structural changes in 2TeO2·V2O5 glass, arising as a result of reactor irradiation with ~1018n/cm2 fast neutrons flux are investigated. A reduction of the coordination number of the Te atoms, as well as rupture of a part of the 0-0 bonds is observed. 相似文献