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81.
Yasui K Tuziuti T Lee J Kozuka T Towata A Iida Y 《The Journal of chemical physics》2008,128(18):184705
Numerical simulations of nonequilibrium chemical reactions inside an air bubble in liquid water irradiated by ultrasound have been performed for various ambient bubble radii. The intensity of sonoluminescence (SL) has also been calculated taking into account electron-atom bremsstrahlung, radiative attachment of electrons to neutral molecules, radiative recombination of electrons and ions, chemiluminescence of OH, molecular emission from nitrogen, etc. The lower bound of ambient radius for an active bubble in SL and sonochemical reactions nearly coincides with the Blake threshold for transient cavitation. The upper bound is in the same order of magnitude as that of the linear resonance radius. In actual experiments, however, the distribution of ambient radius for active bubbles may be narrow at around the threshold ambient radius for the shape instability. The threshold peak temperature inside an air bubble for nitrogen burning is higher than that for oxidant formation. The threshold peak temperatures depend on ultrasonic frequency and acoustic amplitude because chemical reactions inside a bubble are in nonequilibrium. The dominant emission mechanism in SL is electron-atom bremsstrahlung except at a lower bubble temperature than 2000 K, for which molecular emissions may be dominant. 相似文献
82.
Atsuya Muranaka Shigetsugu Homma Hiromitsu Maeda Hiroyuki Furuta Nagao Kobayashi 《Chemical physics letters》2008,460(4-6):495-498
A plus-to-minus MCD sign in ascending energy has been detected for the Q bands of the copper(III) complexes of doubly N-confused porphyrin (cis- and trans-1). An unusual ΔHOMO < ΔLUMO relationship for tetrapyrrolic porphyrins was calculated using the HF, DFT, and semi-empirical methods. By applying the Michl’s perimeter model, the observed MCD pattern was successfully explained by the computational results. 相似文献
83.
Borovkov VV Muranaka A Hembury GA Origane Y Ponomarev GV Kobayashi N Inoue Y 《Organic letters》2005,7(6):1015-1018
[structure: see text] A racemic mixture of the ethane-bridged bis(zinc octaethylchlorin) was successfully resolved for the first time to yield two enantiomers that exhibit substantial CD signals in the regions of chlorin B and Q transitions. The absolute configuration of the corresponding enantiomers was assigned and the origin of its high optical activity was rationalized through a combined spectral, crystallographic, and theoretical analysis. 相似文献
84.
Minami H Yoshida T Okutsu K Zhang Q Inoue S Atsuya I 《Fresenius' Journal of Analytical Chemistry》2001,370(7):855-859
A direct method for determination of silicon in powdered high-purity aluminium oxide samples, by slurry sampling with in situ fusion graphite-furnace atomic-absorption spectrometry (GF-AAS), has been established. A slurry sample was prepared by 10-min ultrasonication of a powdered sample in an aqueous solution containing both sodium carbonate and boric acid as a mixed flux. An appropriate portion of the slurry was introduced into a pyrolytic graphite furnace equipped with a platform. Silicon compounds to be determined and aluminium oxide were fused by the in situ fusion process with the flux in the furnace under optimized heating conditions, and the silicon absorbance was then measured directly. The calibration curve was prepared by use of a silicon standard solution containing the same concentration of the flux as the slurry sample. The accuracy of the proposed method was confirmed by analysis of certified reference materials. The proposed method gave statistically accurate values at the 95% confidence level. The detection limit was 3.3 microg g(-1) in solid samples, when 300 mg/20 mL slurry was prepared and a 10 microL portion of the slurry was measured. The precision of the determination (RSD for more than four separate determinations) was 14% and 2%, respectively, for levels of 10 and 100 microg g(-1) silicon in aluminium oxide. 相似文献
85.
Kosuke Katagiri Takashi Ikeda Atsuya Muranaka Masanobu Uchiyama Masahide Tominaga Isao Azumaya 《Tetrahedron: Asymmetry》2009,20(22):2646-2650
Novel chiral cyclic molecules composed of aromatic triamides were constructed in modest yield from 4-N-(4′-methoxybenzyl)amino-3-decyloxybenzoic acid using dichlorotriphenylphosphorane, because of the preorganized component of the tertiary benzanilide moieties. A racemic mixture of two diastereomers, syn and anti conformers of cyclic aromatic triamides, was resolved into enantiomers by HPLC using a preparative chiral column. The absolute configuration of each enantiomer in both diastereomers was determined by comparison of the time-dependent density functional theory (TD-DFT) calculated circular dichroic (CD) spectra with the experimentally derived CD spectra recorded on each sample. 相似文献
86.
H. Minami Tomomi Yoshida Kentaro Okutsu Qiangbin Zhang Sadanobu Inoue Ikuo Atsuya 《Analytical and bioanalytical chemistry》2001,370(7):855-859
A direct method for determination of silicon in powdered high-purity aluminium oxide samples, by slurry sampling with in situ fusion graphite-furnace atomic-absorption spectrometry (GF-AAS), has been established. A slurry sample was prepared by 10-min ultrasonication of a powdered sample in an aqueous solution containing both sodium carbonate and boric acid as a mixed flux. An appropriate portion of the slurry was introduced into a pyrolytic graphite furnace equipped with a platform. Silicon compounds to be determined and aluminium oxide were fused by the in situ fusion process with the flux in the furnace under optimized heating conditions, and the silicon absorbance was then measured directly. The calibration curve was prepared by use of a silicon standard solution containing the same concentration of the flux as the slurry sample. The accuracy of the proposed method was confirmed by analysis of certified reference materials. The proposed method gave statistically accurate values at the 95% confidence level. The detection limit was 3.3 μg g–1 in solid samples, when 300 mg/20 mL slurry was prepared and a 10 μL portion of the slurry was measured. The precision of the determination (RSD for more than four separate determinations) was 14% and 2%, respectively, for levels of 10 and 100 μg g–1 silicon in aluminium oxide. 相似文献
87.
88.
Prof. Dr. Hiromitsu Maeda Ryo Akuta Dr. Yuya Bando Dr. Kazuto Takaishi Prof. Dr. Masanobu Uchiyama Dr. Atsuya Muranaka Prof. Dr. Norimitsu Tohnai Prof. Dr. Shu Seki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(35):11676-11685
Polygon‐like [2+2]‐ and [3+3]‐type metal complexes were prepared from dipyrrin dimers connected by acute‐angled spacers. The electrical conduction depends strongly on the packing alignment of the compounds, revealing the presence of effective hopping pathways for holes with relatively high mobility up to 0.11 cm2 V?1 s?1 along the aligned axis of [3+3]‐type metal‐bridged assemblies. These observations correlated with the geometrical control of the π‐conjugated metal complexes in the cyclic structures, which enables their ordered arrangement in the assemblies. 相似文献
89.
Muranaka A Ohira S Hashizume D Koshino H Kyotani F Hirayama M Uchiyama M 《Journal of the American Chemical Society》2012,134(1):190-193
An aromatic hemiporphyrazine with an 18π-electron structure has been synthesized by oxidizing 20π-electron 8,10,21,23-tetrahydroxy-28,30-dicarba-27H,29H-hemiporphyrazine with bulky aryl ether substituents. The aromatic nature of the oxidized form was characterized by means of various spectroscopic methods and single-crystal X-ray analysis, with the help of quantum-chemical calculations. The oxidized hemiporphyrazine exhibited an intense absorption at ~850 nm. The redox process was found to be reversible. 相似文献
90.
A method for synthesizing highly strained cyclic structures by combining photochromic and synthetic reactions is described. Tightly linked azobenzene-binaphthyl dyads (R)-4 and (R)-6 could not be obtained by conventional cyclization, but continuous application of photoirradiation, which induced (E)→(Z) isomerization of the azobenzene moiety, allowed the cyclization reaction to proceed, affording the desired chiral azobenzenophanes. 相似文献