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161.
Jasimuddin S Yamada T Fukuju K Otsuki J Sakai K 《Chemical communications (Cambridge, England)》2010,46(44):8466-8468
Supramolecular photosynthetic systems made up of the [Ir(ppy)(2)(bpy)](+) and [Co(bpy)(3)](2+) cores (ppy = 2-phenylpyridinate, bpy = 2,2'-bipyridine) are in situ self-assembled in aqueous media to generate H(2) upon visible light irradiation, where one of them recorded a relatively high turnover number of 20. 相似文献
162.
Kim HK Park JA Kim KM Nasiruzzaman SM Kang DS Lee J Chang Y Kim TJ 《Chemical communications (Cambridge, England)》2010,46(44):8442-8444
We report the synthesis of macrocyclic DTPA conjugates of 1,1'-bis(amino)ferrocenes (1a-b) and their Gd-complexes [Gd(L)(H(2)O)] (2a-b, L = 1a-b) for use as new MRI blood-pool contrast agents. High R(1) relaxivity in HSA as well as high thermodynamic and kinetic stabilities is observed for 2a. 相似文献
163.
Bäcktorp C Wass JR Panas I Sköld M Börje A Nyman G 《The journal of physical chemistry. A》2006,110(44):12204-12212
This study concerns the autoxidation of one of the most used fragrances in daily life, linalool (3,7-dimethyl-1,6-octadien-3-ol). It reacts with O2 to form hydroperoxides, which are known to be important contact allergens. Pathways for hydroperoxide formation are investigated by means of quantum mechanical electronic structure calculations. Optimized molecular geometries and harmonic vibrational frequencies are determined using density functional theory (DFT). Insight into how the addition of O2 to linalool occurs is obtained by establishing a theoretical framework and systematically investigating three smaller systems: propene, 2-methyl-2-butene, and 2-methyl-2-pentene. 2-Methyl-2-pentene was chosen as a model system and used to compare with linalool. This theoretical study characterizes the linalool-O2 biradical intermediate state, which constitutes a branching point for the further oxidation reactions pathways. Thus, the observed linalool oxidation product spectrum is discussed in terms of a direct reaction path, the ene-type mechanism, and the radical mechanism. The major hydroperoxide found in experiments is 7-hydroperoxy-3,7-dimethyl-octa-1,5-diene-3-ol, and the calculated results support this finding. 相似文献
164.
Mubasher Jamil Peter K. F. Kuhfittig Farook Rahaman Sk. A. Rakib 《The European Physical Journal C - Particles and Fields》2010,67(3-4):513-520
It is generally agreed that the acceleration of the Universe can best be explained by the presence of dark or phantom energy. The equation of state of the latter shows that the null energy condition is violated. Such a violation is the primary ingredient for sustaining traversable wormholes. This paper discusses wormholes supported by a more general form called polytropic phantom energy. Its equation of state results in significant generalizations of the phantom-energy and, in some cases, the generalized Chaplygin-gas wormhole models, both of which continue to receive considerable attention from researchers. Several specific solutions are explored, namely, a constant redshift function, a particular choice of the shape function, and an isotropic-pressure model with various shape functions. Some of the wormhole spacetimes are asymptotically flat, but most are not. 相似文献
165.
A. A. Usmani Z. Hasan F. Rahaman Sk. A. Rakib Saibal Ray Peter K. F. Kuhfittig 《General Relativity and Gravitation》2010,42(12):2901-2912
This paper discusses a new type of thin-shell wormhole constructed by applying the cut-and-paste technique to two copies of
a charged black hole in generalized dilaton-axion gravity, which was inspired by low-energy string theory. After analyzing
various aspects of this thin-shell wormhole, we discuss its stability to linearized spherically symmetric perturbations. 相似文献
166.
Sk. Jaker Ali N. D. Chakraborty СК. Якер али Н. Л. Чакраборти 《Analysis Mathematica》1997,23(1):241-257
Иэучается интегрирование по Петтису функции, эаданных на пространстве с конечнои полнои мерои и принимауших эначения в локаляно выпуклом пространстве. Характериэуется интегрируемостя по Петтису скалярно интегрируемои функции в терминах линеиного оператора и билинеиного функционала, ассоциированных с функциеи. Иэвестно, что каздая функция, интегрируемая по Петтису, является равномерно скалярно интегрируемои. Мы рассматриваем обратнуу эадачу и получаем некоторые реэулятаты, которые обобшаут соответствуушие реэулятаты для банаховых пространств. Специаляно рассматриваутся ограниченные скалярные иэмеримые функции. С такими функциями ассоциируется еше один линеиныи оператор и интегрируемостя по Петтису характериэуется в терминах Этого линеиного оператора. 相似文献
167.
An efficient plant regeneration protocol through indirect somatic embryogenesis pathway via callus had been developed from the leaf explant of an ornamental bulbaceous plant Drimiopsis kirkii. Optimum friable calli were induced on Murashige and Skoog (MS) basal medium supplemented with 3.0 mg/l of 2,4-dichlorophenoxyacetic acid and 1.0 mg/l of α-naphthalene acetic acid (NAA). On subculturing the callus on MS medium supplemented with 2.5 mg/l of thidiazuron (TDZ), 73.3 % of the cultures responded with 20.4?±?0.3 somatic embryos (SEs) per 500 mg callus at different stages of development after 6 weeks of culture. The highest response of 86.7 % with 28.3?±?0.5 embryos per 500 mg callus was observed on MS medium supplemented with 2.5 mg/l TDZ and 1.0 mg/l NAA. SEs were encapsulated in calcium alginate beads for the production of synthetic seeds (SSs) and their storability was investigated. The highest SS germination (93.3 %) was observed in 1.0 % sodium alginate followed by 86.7 % germination with 2.5 % sodium alginate. The SSs were stored at three different temperatures (4, 15, and 24?ºC) up to 6 months. The SSs kept at 15 °C showed 64.4 % germinability even after 4 months of storage. Both nonencapsulated and encapsulated SE-derived plants were successfully transferred to soil with 93.3 and 88.3 % survival rate accordingly. Randomly amplified polymorphic DNA (RAPD) analysis revealed that there were no somaclonal variations among the plants produced via somatic embryogenesis and they are true-to-type to their parental plant. These results confirmed the most reliable methods, which can be further used for genetic transformation studies as well as for mass propagation of ornamental D. kirkii at a commercial level. 相似文献
168.
Maximum Noble‐Metal Efficiency in Catalytic Materials: Atomically Dispersed Surface Platinum
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Dr. Albert Bruix Dr. Yaroslava Lykhach Dr. Iva Matolínová M. Sc. Armin Neitzel Dr. Tomáš Skála Dr. Nataliya Tsud Dr. Mykhailo Vorokhta M. Sc. Vitalii Stetsovych M. Sc. Klára Ševčíková Dr. Josef Mysliveček M. Sc. Roman Fiala M. Sc. Michal Václavů Dr. Kevin C. Prince Dr. Stéphanie Bruyère Dr. Valérie Potin Prof. Dr. Francesc Illas Prof. Dr. Vladimír Matolín Prof. Dr. Jörg Libuda Prof. Dr. Konstantin M. Neyman 《Angewandte Chemie (International ed. in English)》2014,53(39):10525-10530
Platinum is the most versatile element in catalysis, but it is rare and its high price limits large‐scale applications, for example in fuel‐cell technology. Still, conventional catalysts use only a small fraction of the Pt content, that is, those atoms located at the catalyst’s surface. To maximize the noble‐metal efficiency, the precious metal should be atomically dispersed and exclusively located within the outermost surface layer of the material. Such atomically dispersed Pt surface species can indeed be prepared with exceptionally high stability. Using DFT calculations we identify a specific structural element, a ceria “nanopocket”, which binds Pt2+ so strongly that it withstands sintering and bulk diffusion. On model catalysts we experimentally confirm the theoretically predicted stability, and on real Pt‐CeO2 nanocomposites showing high Pt efficiency in fuel‐cell catalysis we also identify these anchoring sites. 相似文献
169.
We determine the Hochschild cohomology algebras of the square-free monomial complete intersections. In particular we provide an explicit formula for the cup product which gives the cohomology module an algebra structure and then we describe this structure in terms of generators and relations. In addition, we compute the Hilbert series of the Hochschild cohomology of these algebras. 相似文献
170.
Ane Funderud Heidi H Henanger Tilahun T Hafte Paul S Amieux Sigurd Ørstavik Bjørn S Skålhegg 《BMC biochemistry》2006,7(1):1-10