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991.
Ilya Bednyakov Leonti Labzowsky Günter Plunien Gerhard Soff Valentin Karasiev 《Hyperfine Interactions》2001,132(1-4):363-366
We derive the electroweak radiative corrections to the basic PNC atomic transition amplitude for highly charged hydrogenlike
ions. In the case of highly charged ions (HCI) effects of strong fields are reflected by the momentum transfer q
2 involved. It is of the order q
2≈m
e
2 inHCI, while q
2≈0 inneutral atoms. This may open the possibility to search for “new physics” beyond the Standard Model and to test the Standard
Model in experiments with HCI.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
992.
S O Akapo J M Dimandja D R Kojiro J R Valentin G C Carle 《Journal of chromatography. A》1999,843(1-2):147-162
Gas chromatography has proven to be a very useful analytical technique for in situ analysis of extraterrestrial environments as demonstrated by its successful operation on spacecraft missions to Mars and Venus. The technique is also one of the six scientific instruments aboard the Huygens probe to explore Titan's atmosphere and surface. A review of gas chromatography in previous space missions and some recent developments in the current environment of fiscal constraints and payload size limitations are presented. 相似文献
993.
Lincoln Chayes Senya B. Shlosman Valentin A. Zagrebnov 《Journal of statistical physics》2000,98(3-4):537-549
We study the annealed site-diluted versions of the classical O(n) Heisenberg ferromagnets. It is shown that if the temperature is low enough, then at some value of the chemical potential there is phase coexistence between a magnetized, high-density state (liquid-crystal state) and a low-density state (gaseous state) with no magnetic order. 相似文献
994.
We study error bounds in the operator norm topology for the Trotter-Kato product formula. We prove that they depend on fractional power conditions (domains and relative boundedness) for operators involved in this formula.Dedicated to Professor M.Sh.BIRMAN on the occassion of his 70th birthday. 相似文献
995.
Elaborated methods of synthesis of chemically modified silicas with grafted silicon hydride and amino groups are analyzed. Experimental results on use of modified silicas with bonded amino groups as fillers of carboxyl-containing rubbers and epoxy resins are reported. It was shown that modified silica fillers with grafted silicon hydride groups could be applied for carrying out processes of catalytic solid-phase hydrosilylation of 2-hydroxyethylmethacrylate and some other functional olefins. 相似文献
996.
Tatyana Usacheva Irina Terekhova Diana Alister Mikhail Agafonov Natalya Kuranova Dmitry Tyurin Valentin Sharnin 《Entropy (Basel, Switzerland)》2022,24(1)
The analysis of the ratios of entropy and enthalpy characteristics and their contributions to the change in the Gibbs energy of intermolecular interactions of crown ethers and cyclodextrins with amino acids is carried out. Two different types of macrocycles were chosen for examination: crown ethers with a hydrophilic interior and cyclodextrins with a hydrophobic inner cavity and a hydrophilic exterior. The thermodynamics of complex formation of crown ethers and cyclodextrins with amino acids in water and aqueous-organic solvents of variable composition was examined. The contributions of the entropy solvation of complexes of 18-crown-6 with glycine, alanine, phenylalanine to the change in the entropy of complexation in water-ethanol and water-dimethyl sulfoxide solvents was calculated and analyzed. It was found that the ratios of the entropy and enthalpy solvation of the reagents for these systems have similar trends when moving from water to aqueous-organic mixtures. The relationship between the thermodynamic characteristics and structural features of the complexation processes between cyclodextrins and amino acids has been established. The thermodynamic enthalpy–entropy compensation effect was revealed, and its features for complexation of cyclodextrins and 18-crown-6 were considered. It was concluded that, based on the thermodynamic parameters of molecular complexation, one could judge the mode of the formation of complexes, the main driving forces of the interactions, and the degree of desolvation. 相似文献
997.
Jonathan Decaens Dr. Samuel Couve-Bonnaire Prof. Dr. André B. Charette Prof. Dr. Thomas Poisson Prof. Dr. Philippe Jubault 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(9):2935-2962
This Minireview describes recent advances toward the synthesis of fluoro-, monofluoromethyl-, difluoromethyl-, and trifluoromethyl-substituted three-membered rings such as cyclopropanes, aziridines, epoxides, episulfides, cyclopropenes, and 2 H-azirines. The main synthetic methodologies since 2016 for cyclopropanes and since 2010 for the other three-membered rings are reported. 相似文献
998.
Todea Anamaria Aparaschivei Diana Bîtcan Ioan Ledeți Ionuț Valentin Bandur Geza Péter Francisc Nagy Lajos Kéki Sándor Biró Emese 《Journal of Thermal Analysis and Calorimetry》2020,141(3):1017-1026
Journal of Thermal Analysis and Calorimetry - The thermal behavior of co-oligomers of ε-caprolactone (ECL) with gluconolactone, compared to the ε-caprolactone oligomer, has been assessed... 相似文献
999.
Kirill P. Cheremnykh Victor A. Savelyev Sergey A. Borisov Igor D. Ivanov Dmitry S. Baev Tatyana G. Tolstikova Valentin A. Vavilin Elvira E. Shults 《Molecules (Basel, Switzerland)》2020,25(23)
Convenient and efficient routes to construct hybrid molecules containing diterpene alkaloid lappaconitine and pyrimidine fragments are reported. One route takes place via first converting of lappaconitine to 1-ethynyl-lappaconitine, followed by the Sonogashira cross-coupling-cyclocondensation sequences. The other involves the palladium-catalyzed carbonylative Sonogashira reaction of 5′-iodolappaconitine with aryl acetylene and Mo (CO)6 as the CO source in acetonitrile and subsequent cyclocondensation reaction of the generated alkynone with amidines. The reaction proceeded cleanly in the presence of the PdCl2-(1-Ad)2PBn∙HBr catalytic system. The protocol provides mild reaction conditions, high yields, and high atom and step-economy. Pharmacological screening of lappaconitine-pyrimidine hybrids for antinociceptive activity in vivo revealed that these compounds possessed high activity in experimental pain models, which was dependent on the nature of the substituent in the 2 and 6 positions of the pyrimidine nucleus. Docking studies were undertaken to gain insight into the possible binding mode of these compounds with the voltage-gated sodium channel 1.7. The moderate toxicity of the leading compound 12 (50% lethal dose (LD50) value was more than 600 mg/kg in vivo) and cytotoxicity to cancer cell lines in vitro encouraged the further design of therapeutically relevant analogues based on this novel type of lappaconitine–pyrimidine hybrids. 相似文献
1000.
Yana I. Sakhno Anton V. Kozyryev Sergey M. Desenko Svetlana V. Shishkina Vladimir I. Musatov Dmytro O. Sysoiev Valentin A. Chebanov 《Tetrahedron》2018,74(5):564-571
Three-component heterocyclizations of pyruvic acids and their esters with 5-aminopyrazoles and aromatic aldehydes, in addition to the sequential versions of these reactions, under different activating conditions were studied. Under conventional heating, pyrazolopyrimidine derivatives containing a hydroxyl group in the 6-position were formed in both two- and three-component treatments. Whereas the application of an inert atmosphere did not influence the outcome of these reactions, the use of ultrasonic irradiation led to the formation of 7-hydroxy-tetrahydropyrazolopyrimidines in multi-component reactions and 6-hydroxy-dihydropyrazolopyrimidines in the case of a step-by-step approach. The products of the latter treatment were further transformed into heteroaromatized 6-hydroxy-pyrazolopyrimidines by conventional heating. 相似文献