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81.
S. V. Demin N. A. Shokurova L. I. Demina L. G. Kuz’mina V. I. Zhilov A. Yu. Tsivadze 《Russian Journal of Inorganic Chemistry》2018,63(1):121-127
Chloroform–water extraction systems have been studied using crown-ethers as extracting agents, namely: benzo-15-crown-5 (B15C5), 2,3-naphtho-15-crown-5 (N15C5), 4′-nitro-benzo-15-crown-5 (NO2B15C5), 4′-tert-butyl-benzo-15-crown-5 (TBB15C5), and 4′-acetyl-benzo-15-crown-5 (AcB15C5). Extraction isotherms of these systems have been obtained, and an attempt made to elucidate the effect of the structure of extracting agent on extraction characteristics. IR-spectroscopic studies have been performed for selected crown-ethers and their complexes in crystalline form and in chloroform solutions, namely, for N15C5, NO2B15C5, AcB15C5, and B15C5. The complexes LiN15C5H2OClO4 (1), LiN15C5H2OI (2), LiNO2B15C5H2OI (3), LiAcB15C5H2OI (4), and LiTBB15C5H2OI (5) have been isolated for the first time and characterized by IR spectroscopy. Single-crystal X-ray data have been obtained for complexes 1–3. 相似文献
82.
Lindemuth IR Reinovsky RE Chrien RE Christian JM Ekdahl CA Goforth JH Haight RC Idzorek G King NS Kirkpatrick RC Larson RE Morgan GL Olinger BW Oona H Sheehey PT Shlachter JS Smith RC Veeser LR Warthen BJ Younger SM Chernyshev VK Mokhov VN Demin AN Dolin YN Garanin SF Ivanov VA Korchagin VP Mikhailov OD Morozov IV Pak SV Pavlovskii ES Seleznev NY Skobelev AN Volkov GI Yakubov VA 《Physical review letters》1995,75(10):1953-1956
83.
B. P. Zolotovskii R. A. Buyanov G. A. Bukhtiyarova V. V. Demin A. M. Tsybulevskii 《Reaction Kinetics and Catalysis Letters》1995,55(2):523-535
A new low-waste technology for production of the alumina catalyst at the Claus process has been developed. The catalytic activity of the Claus alumina catalysts (IC-27-22) produced by this technology is close to that of the best foreign samples (CR and S-100).VNIIGAS 相似文献
84.
E. É. Glikman Yu. V. Goryunov V. M. Demin K. Yu. Sarychev 《Russian Physics Journal》1976,19(7):839-843
Relations have been derived here between the macroscopic characteristics of liquid metal embrittlement (durability c under creep and strain c prior to rupture under tension) and the parameters which characterize the micromechanism of fracture (surface energy at the crystal bath interface, energy of grain boundaries, temperature, structure of the crystal-bath interface, etc.), on the basis of test data indicating that the subcritical stage of microcrack development governs the fracture process, and on the assumption that transition to supercritical fracture occurs when the crack angle at the tip opens to its critical width c. It is also shown here that, as the rate of subcritical crack development changes by three orders of magnitude, the magnitude of the critical angle c changes only by a factor of 3.0 and may, to the first approximation, be regarded as independent of the bath composition. The values of c and c calculated according to this approximation agree closely enough with values based on tests.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 22–29, July, 1976. 相似文献
85.
V. V. Yakshin O. N. Vilkova N. A. Tsarenko S. V. Demin V. I. Zhilov A. Yu. Tsivadze 《Russian Journal of Coordination Chemistry》2006,32(2):77-81
The distribution coefficients of the alkaline and alkali-earth metal nitrates are determined for the processes of extraction from nitric acid solutions with crown ethers, which differ in sizes of their cycles (from 18 to 22 atoms) and in side phenyl and cyclohexyl substituents, but have unchanged number of the O atoms in a cycle. The phenyl and cyclohexyl derivatives of 18-crown-6 are found to be more efficient extractants of alkali metals as compared with unsubstituted crown ethers. However, the selectivity of separation of a pair Cs-Na remains low. The 18-crown-6 derivatives with one and two cyclohexyl fragments selectively extract Sr, which can be used to separate it from the remaining alkali and alkaline-earth metals. An increase in the size of a macrocycle from 18 to 20 and 22 atoms leads to a reduction in the extraction efficiency for all alkali and alkaline-earth metals, insignificantly improves separation of a pair Cs-Na, but noticeably deteriorates Sr-Na separation. 相似文献
86.
D. A. Medvedev E. V. Gorbova A. K. Demin B. D. Antonov 《Russian Journal of Electrochemistry》2011,47(12):1404-1410
In the present work, samples with the composition of BaCe0.77 − x
Zr
x
Gd0.2Cu0.03O3 − δ (x = 0, 0.1…0.7, 0.77) were synthesized according to the standard solid state technique. The effect of zirconium oxide on the
phase character, structure, and conductivity was studied using the methods of X-ray diffraction analysis, scanning electron
microscopy, and four-probe method, accordingly. Stability of these materials in the flow of carbon dioxide was studied. The
results show that introduction of zirconium oxide leads to preservation of a single-phase system (x ≤ 0.6), a decrease in the grain size, and an increase in stability in the CO2 atmosphere. 相似文献
87.
With the use of the one-dimensional Burgers equation, the evolution of a high-intensity noise with periodically modulated intensity is analyzed. The nonlinearity is shown to lead to partial suppression of the amplitude modulation and to the generation of a regular low-frequency component. The probability distributions and the power spectra of the field are studied. 相似文献
88.
In this paper, three iterative methods (Stokes, Newton and Oseen iterative methods) based on finite element discretization for the stationary micropolar fluid equations are proposed, analyzed and compared. The stability and error estimation for the Stokes and Newton iterative methods are obtained under the strong uniqueness conditions. In addition, the stability and error estimation for the Oseen iterative method are derived under the uniqueness condition of the weak solution. Finally, numerical examples test the applicability and the effectiveness of the three iterative methods. 相似文献
89.
范克龙 高利增 魏辉 江冰 王大吉 张若飞 贺久洋 孟祥芹 王卓然 樊慧真 温涛 段德民 陈雷 姜伟 芦宇 蒋冰 魏咏华 李唯 袁野 董海姣 张鹭 洪超仪 张紫霞 程苗苗 耿欣 侯桐阳 侯亚欣 李建茹 汤国恒 赵越 赵菡卿 张帅 谢佳颖 周子君 任劲松 黄兴禄 高兴发 梁敏敏 张宇 许海燕 曲晓刚 阎锡蕴 《化学进展》2023,35(1):1-87
纳米酶(Nanozymes)是由我国科学家首次提出的新概念,它是一类具有生物催化功能的纳米材料,能够基于特定的纳米结构催化天然酶的底物并作为酶的代替品。自2007年首次报道以来,全球已有来自于55个国家的420多个研究机构证实了纳米酶的普遍规律。纳米酶的发现第一次揭示纳米材料蕴含一种独特的纳米效应——类酶催化效应。纳米酶作为一种新材料,既有纳米材料本身的理化性质,又有类似酶的催化功能,兼具天然酶与人工酶的优势于一身。其中,纳米结构不仅赋予纳米酶高效催化功能,而且使纳米酶比天然酶稳定,易于规模化生产。另外,纳米酶独特的多酶活性将为设计廉价、稳定、各种各样全新的催化级联反应提供功能分子。纳米酶是多学科交叉融合的典范,2022年被IUPAC评为十大化学新兴技术。在全球从事化学、酶学、材料学、生物学、医学、理论计算等多领域科学家的共同推进下,如今纳米酶已经成为新的研究热点。我国科学家在这一新兴领域一直发挥着引领作用,解析了纳米酶的构-效关系,将其催化活性提高了约1万倍,实现了超越天然酶的理性设计,创造了全球首个纳米酶产品,出版了纳米酶学英文专著,发布纳米酶术语及中国/国际标准化。更可喜的是,纳... 相似文献
90.
In this paper, a driving stress finite element method of elastic-plastic large deformation based on implicit time integrating
algorithm and an eight-chain molecular network model is used for the numerical simulation of the simple shear test of polycarbonate
(PC) materials. The simulated results are compared with experimental ones. The strain localization propagation for the shear
band deformation for simple shear deformation is investigated numerically. The effects of microstructure parameters in the
model on strain softening and orientation hardening of the PC are discussed in detail.
Supported by the National Natural Science Foundation of China. 相似文献