排序方式: 共有159条查询结果,搜索用时 31 毫秒
41.
Tetraphenylporphyrins carrying primary or tertiary alcohols in a phenyl group were bonded to silicate glass by heat treatment. The rate of base catalyzed hydrolysis of tertiary ester was 20 times slower than that of primary ester, while the rate of acid catalyzed hydrolysis of tertiary ester was only 2.5 times slower than that of primary ester. Hydrolysis of tertiary alcohol bonded silica in HCl/H218O displayed that there is a covalent bond between alcohol oxygen and silicon, and the C–O bond is cleaved under acidic conditions, while the Si–O bond is cleaved under basic conditions. 相似文献
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Masafumi Akahira Nao Ohyauchi 《Annals of the Institute of Statistical Mathematics》2002,54(4):806-815
For a family of non-regular distributions with a location parameter including the uniform and truncated distributions, the stochastic expansion of the Bayes estimator is given and the asymptotic lower bound for the Bayes risk is obtained and shown to be sharp. Some examples are also given. 相似文献
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Hosaka N Otsuka H Hino M Takahara A 《Langmuir : the ACS journal of surfaces and colloids》2008,24(11):5766-5772
The influence of the dispersion states of the nanofillers on the dewetting behavior of the polymer thin film was investigated. Polyhedral oligomeric silsesquioxanes (POSS) with various substituents were added into polystyrene (PS) thin films as the nanofillers. The dewetting rate of the films drastically changed with the surface substituents of POSS additives. Neutron reflectivity measurements indicated that the difference of the dewetting rate was associated with the dispersion state of POSS additives in the films. POSS with phenethyl groups (PhPOSS), which homogeneously dispersed into the films, resulted in the decrease of the glass transition temperature of PS and the enhancement of the dewetting of the films. POSS with a fluoroalkyl group (CpPOSS-R f) segregated to the film surface and showed the retardation of the dewetting by the decrease of the surface energy of the film. POSS with hydroxyl groups (CpPOSS-2OH) segregated to the film surface and film-substrate interface and led to the elimination of the dewetting, suggesting the importance of the interfacial segregation for the inhibition of dewetting. These results revealed the strong relationship between the dispersion state of the nanofillers and the dewetting of the nanofilled films. 相似文献
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Remarkable Charge Separation and Photocatalytic Efficiency Enhancement through Interconnection of TiO2 Nanoparticles by Hydrothermal Treatment 下载免费PDF全文
Prof. Yusuke Ide Nozomu Inami Hideya Hattori Kanji Saito Dr. Minoru Sohmiya Prof. Nao Tsunoji Prof. Kenji Komaguchi Prof. Tsuneji Sano Prof. Yoshio Bando Prof. Dmitri Golberg Prof. Yoshiyuki Sugahara 《Angewandte Chemie (International ed. in English)》2016,55(11):3600-3605
Although tremendous effort has been directed to synthesizing advanced TiO2, it remains difficult to obtain TiO2 exhibiting a photocatalytic efficiency higher than that of P25, a benchmark photocatalyst. P25 is composed of anatase, rutile, and amorphous TiO2 particles, and photoexcited electron transfer and subsequent charge separation at the anatase–rutile particle interfaces explain its high photocatalytic efficiency. Herein, we report on a facile and rational hydrothermal treatment of P25 to selectively convert the amorphous component into crystalline TiO2, which is deposited between the original anatase and rutile particles to increase the particle interfaces and thus enhance charge separation. This process produces a new TiO2 exhibiting a considerably enhanced photocatalytic efficiency. This method of synthesizing this TiO2, inspired by a recently burgeoning zeolite design, promises to make TiO2 applications more feasible and effective. 相似文献
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Horike S Tanaka D Nakagawa K Kitagawa S 《Chemical communications (Cambridge, England)》2007,(32):3395-3397
An interdigitated porous coordination polymer with hydrophobic pore surface shows size and affinity dependent selective gas sorption properties accompanying the reversible structure transformation. 相似文献
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Nao Kamei-Ishikawa Keiko Tagami Shigeo Uchida 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):247-252
Plant uptake of radiocesium (137Cs) was investigated in consideration of the relationships with naturally existing 133Cs and potassium (K). We first determined plant-unavailable fraction of 137Cs in soil by batch sorption and sequential extraction methods with a radiotracer. Then, using the data obtained from the
batch sorption and extraction methods, we clarified the relationships of plant-available and plant-unavailable fractions between
137Cs, 133Cs, and K in soil. Additionally, 137Cs concentrations in crop were estimated using 137Cs in soil and several factors, i.e. fixation ratio of 137Cs in soil, cation exchange capacity, and K concentration in crop. The results implied that the fixation ratio of 137Cs in soil was a very important key to understanding 137Cs plant uptake. 相似文献
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Yanai N Uemura T Horike S Shimomura S Kitagawa S 《Chemical communications (Cambridge, England)》2011,47(6):1722-1724
A complex of polyethylene glycol with LiBF(4) was incorporated into the nanochannels of a porous coordination polymer, where a liquid-like mobility of the Li ions was attained, even within the highly constrained geometry. 相似文献
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T Fukushima S Horike H Kobayashi M Tsujimoto S Isoda ML Foo Y Kubota M Takata S Kitagawa 《Journal of the American Chemical Society》2012,134(32):13341-13347
The mesoscale design of domain assembly is crucial for controlling the bulk properties of solids. Herein, we propose a modular design of domain assembly in porous coordination polymer crystals via exquisite control of the kinetics of the crystal formation process. Employing precursors of comparable chemical reactivity affords the preparation of homogeneous solid-solution type crystals. Employing precursors of distinct chemical reactivity affords the preparation of heterogeneous phase separated crystals. We have utilized this reactivity-directed crystallization process for the facile synthesis of mesoscale architecture which are either solid-solution or phase-separated type crystals. This approach can be also adapted to ternary phase-separated type crystals from one-pot reaction. Phase-separated type frameworks possess unique gas adsorption properties that are not observed in single-phasic compounds. The results shed light on the importance of crystal formation kinetics for control of mesoscale domains in order to create porous solids with unique cooperative functionality. 相似文献