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排序方式: 共有131条查询结果,搜索用时 15 毫秒
41.
Aminov R. I. Karimova I. M. Khusnutdinov R. I. 《Russian Journal of Organic Chemistry》2020,56(9):1595-1599
Russian Journal of Organic Chemistry - New methods have been developed for the synthesis of previously unknown ω-(hexacyclo[9.2.1.02,7.03,5.04,8.09,13]tetradecan-10-exo-yloxy)alkan-1-ols and... 相似文献
42.
L. K. Aminov M. R. Gafurov I. N. Kurkin A. A. Rodionov 《Applied magnetic resonance》2014,45(11):1147-1156
Electron paramagnetic resonance (EPR) of the mixed fluorite crystals with the general formula (MeF2)1?x?y (REF3) x (RF3) y (Me = Ca, Sr, Ba; R = Y, La, Lu; RE—paramagnetic trivalent rare-earth ions) were studied comprehensively by different authors and several structural models of paramagnetic centers were considered. However, a lot of details of EPR spectra still remain unexplained. In this work some modifications of the simplest models are proposed which allow explaining adequately the variety of the tetragonal centers in crystals grown under the different conditions. The calculated from the proposed models components of g-factors for Ce3+, Nd3+, Sm3+, Er3+ ions are in a good agreement with the experimental values. 相似文献
43.
Chemistry of Natural Compounds - 相似文献
44.
45.
Quinoline Synthesis by the Reaction of Anilines with 1,2‐diols Catalyzed by Iron Compounds 下载免费PDF全文
Ravil Khusnutdinov Alfiya Bayguzina Rishat Aminov Usein Dzhemilev 《Journal of heterocyclic chemistry》2016,53(4):1022-1029
The synthesis of quinoline derivatives by cyclocondensation of anilines with 1,2‐ethanediol, 1,2‐propanediol, and 1,2‐butanediol in the presence of iron‐containing catalysts was performed for the first time. 相似文献
46.
L. K. Aminov A. A. Ershova V. N. Efimov S. L. Korableva I. N. Kurkin B. Z. Malkin A. A. Rodionov 《Physics of the Solid State》2010,52(10):2070-2075
The EPR spectra of Ce3+ impurity ions in LiYF4, LiLuF4, and LiTmF4 double-fluoride single crystals have been investigated at a frequency of ∼9.3 GHz in the temperature range 5–25 K. The effective
g factors of the ground Kramers doublet of the cerium ions in three crystals are close to each other (g
‖ = 2.737, g
⊥ = 1.475 for LiYF4:Ce3+). A superhyperfine structure of the EPR spectrum of Ce3+ ions in the LiTmF4 Van Vleck paramagnet has been observed in the external magnetic field B oriented along the crystallographic axis c (B ‖ c). The superhyperfine structure of the EPR soectra of the Ce3+ ions in the LiYF4 and LiLuF4 diamagnetic matrices is resolved for B ⊥ c. Possible factors responsible for this pronounced difference in the properties of the systems studied have been discussed. 相似文献
47.
L. K. Aminov A. A. Ershova D. G. Zverev S. L. Korableva I. N. Kurkin B. Z. Malkin 《Applied magnetic resonance》2008,33(4):351-364
Electron paramagnetic resonance (EPR) spectra of doped paramagnetic crystals LiLuF4:U3+ and LiYF4:Yb3+ have been investigated at a frequency of about 9.42 GHz in the temperature range of 10–20 K. The U3+ ion spectrum is characterized by g-factors g
∥ = 1.228 and g
⊥ = 2.516, and contains the hyperfine structure due to the 235U isotope with nuclear spin I = 7/2 and natural abundance of 0.71%. The observed hyperfine interaction constants are A
∥ = 81 G and A
⊥ = 83.8 G. Moreover, the spectrum reveals the well-resolved superhyperfine structure (SHFS) due to two groups of four fluorine
ions forming the nearest surrounding of the U3+ ion. This SHFS contains up to nine components with the spacing between components being about 12.7 G. The SHFS is observed
also in the EPR spectrum of the LiYF4:Yb3+ crystal; up to 17 components with spacing of about 3.7 G may be traced. Some parameters of the effective Hamiltonian of the
SHF interaction are estimated, the contribution of covalent bonding of f-electrons with ligands into these parameters is discussed.
Authors' address: Igor N. Kurkin, Kazan State University, Kremlevskaya ulitsa 18, Kazan 420008, Russian Federation 相似文献
48.
49.
E. S. Nefed’ev K. M. Musin T. Yu. Mirakova M. K. Kadirov K. L. Aminov K. M. Salikhov V. A. Silaev 《Applied magnetic resonance》1996,11(1):115-123
The distribution of paramagnetic centres in carbon black filler in the interphase layer of the thiokol-epoxy hermetics on the border of brass or glass substrate was studied using EPR-imaging method. It was shown that the relative content of radicals decreases near the hermetic-“rigid” surface contact border. The thickness of the layer with a low concentration of radicals is estimated as 0.5±0.3 mm. The inhomogeneous distribution of radicals is more obvious in the case of hermetic hardening on a brass surface. These results are explained by a catalytic acceleration of the thiokol-epoxy polymerization reaction in the region of hermetic-metal surface contact. 相似文献
50.
Temperature dependence of the critical current in YBa2Cu3O7−δ and Bi2Sr2Ca1Cu2O8 Josephson junctions
B. A. Aminov N. B. Brandt Nguyen Min Thuy Ya. G. Ponomarev M. V. Sudakova
A. R. Kaul
I. E. Graboi Yu. D. TretiakovJ. Wittig
S. P. Kobeleva
L. M. FisherL. Rosta
《Physica C: Superconductivity and its Applications》1989,160(5-6):505-510We have studied the stationary Josephson effect on YBa2Cu3O7−δ (Tc=90 K) and Bi2Sr2Ca1Cu2 O8 (Tc=80 K and 87 K for two samples of different origin) ceramic based junctions. The temperature dependence of the critical current near Tc has been found as Ic≈(Tc-T)
for the Y-Ba-Cu-O samples indicating that they should be classified as S-N-I-N-S type junctions. The I-V curves of the Bi-Sr-Ca-Cu samples show the typical behaviour of S-I-S structures. Using Ambegaokar-Baratoff's theory for Bi2Sr2Ca1Cu2O8, the temperature dependence of the superconducting state gap Δ(T) was calculated and it was evaluated that 1.452Δ(0)/kBTc3.5. 相似文献