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191.
Shizuka Anan Yumi Mochizuki Kenta Kokado Kazuki Sada 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(24):8102-8107
The A–A/B–B step‐growth copolymerization between a monomer immobilized in the crystalline state and a monomer mobile in the solution state is demonstrated. One of the two monomers was immobilized as organic ligands of the metal–organic framework (MOF) and polymerized with the mobile guest monomer, resulting in the formation of linear polymers. The polymerization behavior was completely different from that of the solution polymerizations. In particular, the degrees of polymerization (DP) converged to a specific value depending on the MOF structures. The inevitable termination is caused not by imperfectness of the polymerization reaction, but by the selection of the two polymerization partners among the several adjacent immobilized monomers. This is fully supported by the Monte Carlo simulation on the basis of the polymerization mechanism. Precise immobilization of monomers in the supramolecular assemblies is a promising way for the controlled A–A/B–B step‐growth polymerization. 相似文献
192.
Kimoto K Anan Y Asaka T Zhigadlo ND Muromachi E Matsui Y 《Journal of electron microscopy》2001,50(4):307-310
Elemental analysis in an oxycarbonate superconductor ((Cu,N,C)Sr2CaCu2Oy) is conducted using transmission electron microscope-electron energy-loss spectroscopy with detector-gain correction. The gain correction enables highly sensitive elemental analysis and precise measurement of energy-loss near edge structures (ELNESs). It is found that carbon is included as a CO3 group, because the carbon K-edge in the oxycarbonate shows the same ELNES observed from CaCO3. Nitrogen ELNES is similar to that of Sr(NO3)2, so nitrogen is contained as a NO3 group. Although both CO3(2-) and NO3- have similar planar atomic arrangements, the nitrogen ELNES observed is different from that of carbon. EEL spectrum simulation based on DV-Xalpha method is used to interpret the difference. 相似文献
193.
I. A. Denisov A. G. Selivanov K. V. Yumashev A. V. Anan’ev L. V. Maksimov N. V. Ovcharenko V. N. Bogdanov A. A. Lipovskii A. N. Vlasova 《Journal of Applied Spectroscopy》2007,74(6):866-871
We have studied the nonlinearity of the refractive index at a wavelength of 1.08 μm for optical lead silicate and lead phosphate
tellurite glasses of different compositions. We have shown that the nonlinear refractive index n2 increases as the lead content increases in lead silicate glasses and as the tellurium content increases in lead phosphate
tellurite glasses, where the latter are typically have higher values of n2, as high as 24·10−13 cgs units (47·10−16 cm2/W), and lower Rayleigh losses. We have established a correlation between the nonlinear refractive index and the microstructure
of the studied glasses. The highly nonlinear glasses are distinguished by extensive fluctuations in the heavy metal oxide
concentration which are “frozen” during cooling of the glass melt.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 780–784, November–December, 2007. 相似文献
194.
Yasumi Anan Takahiro Mikami Yoshiro Tsuji Yasumitsu Ogra 《Analytical and bioanalytical chemistry》2011,399(5):1765-1772
The distribution and metabolism of selenohomolanthionine (4,4′-selenobis[2-aminobutanoic acid], SeHLan), a newly identified
selenoamino acid in selenized Japanese pungent radish, were evaluated by administering 77Se-labeled SeHLan at a dose of 25 μg/kg body weight in rats. Exogenous 77Se of SeHLan was preferably distributed to the kidneys and remained in the intact form for up to 6 h after dosing. The accumulation
in the kidneys is one of the specific characteristics of SeHLan, differing from other selenoamino acids, such as selenomethionine
and Se-methylselenocysteine, which preferably accumulate in the pancreas. The intact form of SeHLan was detected in the serum and
kidney supernatant but not in the urine, suggesting that the amount of exogenous Se that was distributed to the kidneys was
within metabolic capacity. Indeed, the exogenous Se was converted into two urinary metabolites, Se-methylseleno-N-acetyl-galactosamine and trimethylselenonium. Exogenous Se was also detected in several selenoproteins, including selenoprotein
P and extracellular glutathione peroxidase. SeHLan is expected to be a potential supplemental source of Se because its distribution
differs from that of selenomethionine and Se-methylselenocysteine. 相似文献
195.
Two combined quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulations, namely B3LYP/MM and MP2/MM, have been performed to investigate the possible influence of electron correlation on the structure and dynamics of the H(3)O(+) hydrate. In comparison to the previously published HF/MM results, both B3LYP/MM and MP2/MM simulations clearly reveal stronger H(3)O(+)-water hydrogen bond interactions, which are reflected in a slightly greater compactness of the H(3)O(+) hydrate. However, the B3LYP/MM simulation, although providing structural details very close to the MP2/MM data, shows an artificially slow dynamic nature of some first shell water molecules as a consequence of the formation of a long-lived H(3)O(+)···H(2)O hydrogen bonding structure. 相似文献
196.
B. P. Aduev D. R. Nurmukhametov I. Yu. Liskov A. V. Kalenskii M. V. Anan’eva A. A. Zvekov 《Russian Journal of Physical Chemistry B, Focus on Physics》2015,9(6):915-920
The critical fluence of the initiation of the explosive decomposition of pentaerythritol tetranitrate (PETN) by the second harmonic of a neodymium laser (532 nm) is found to be 12.3 J/cm2. It is shown that, under these conditions, the nonlinear two-photon absorption of light takes place. The critical fluence of the initiation of PETN explosive decomposition in the two-photon absorption mode is calculated within the framework of the thermal explosion model (14.7 J/cm2), which indicates that the thermal mechanism of explosive decomposition is operative under these conditions. 相似文献
197.
V. D. Pautov T. N. Nekrasova T. D. Anan’eva T. K. Meleshko D. M. Ilgach A. V. Yakimansky 《Polymer Science Series A》2013,55(9):526-534
A “dark” copolyimide with regularly grafted side chains of polymethacrylic acid and a luminescence-labeled copolyimide containing an anthracene label covalently attached to side chains with an average polycondensation degree of the polyimide backbone of ~16 and an average polymerization degree of side poly(methacrylic acid) chains of ~100 are synthesized. Relaxation times τIMM characterizing the mobility of parts of side chains in solvents of different thermodynamic qualities for the backbone and side chains are determined through the polarized luminescence method. It is shown that, in a “common” solvent for the backbone and side chains, the values of τIMM are close to those characterizing the mobility of linear polymethacrylate chains. In selective solvents, changes in τIMM are related to not only changes in intramolecular interactions but also changes in the heterogeneity of the dynamic characteristics of parts of grafted chains arranged at different distances from the grafting point. 相似文献
198.
V. M. Berestovitskaya O. S. Vasil’eva E. S. Ostroglyadov I. N. Tyurenkov I. V. Anan’ev K. A. Lyssenko V. N. Perfilova V. V. Bagmetova 《Russian Chemical Bulletin》2013,62(11):2401-2406
Acid hydrolysis of 4-(het)aryl-3,5,5-tris(alkoxycarbonyl)-2-pyrrolidones obtained by the condensation of 1,1-bis(alkoxycarbonyl)ethenes with diethyl acetylaminomalonate leads to (2R*,3R*)-3-(het)arylglutamic acid hydrochlorides. 相似文献
199.
M. N. Nikolaeva T. D. Anan’eva A. A. Martynenkov E. P. Astapenko Yu. M. Boiko 《Russian Journal of Applied Chemistry》2013,86(5):756-759
The influence of weight-average molecular mass M w on the maximal width of a conducting layer h max of polysterene, polymethylmethacrylate, and polyamidine films was investigated. It was shown that h max increases in proportion to M w S for all investigated polymers. It points to the fact that the h max value is defined by the macromolecular coil size. 相似文献
200.
V. D. Anan’ev A. A. Belyakov M. V. Bulavin A. E. Verkhoglyadov S. A. Kulikov K. A. Mukhin E. P. Shabalin 《Technical Physics》2014,59(2):283-286
The first criticality of a new KZ-202 neutron moderator on the IBR-2M reactor is achieved. The moderator consists of thermal and cold units. The former is a room-temperature comb water moderator; the latter, a moderator using a mixture of aromatic hydrocarbons (mesitylene and m-xylene). The cold moderator is filled with granules of this mixture, which are supplied by a cold helium flow, and operates at 30 K. The combination of two units in one moderator makes it possible to simultaneously take the thermal and cold neutron spectra for extracted-beam spectrometers. The arrangement of the thermal and cold moderators is numerically optimized by the Monte Carlo method. The use of the cold moderator allows a 13-fold increase in the cold neutron intensity from its surface. 相似文献