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91.
Roberto Magari 《Annali di Matematica Pura ed Applicata》1967,75(1):277-311
Sunto Si studiano certe classi equazionali di algebre, comprendenti in particolare le algebre di Post.
Lavoro eseguito nell’ambito dell’attività dei gruppi di ricerca matematici del C.N.R. (per l’anno 1965–’66). 相似文献
92.
We report the existence of collective excitations of spins in TMMC at high magnetic fields and low temperatures, but higher than TN at zero magnetic field. The main features of the resonances can be attributed to those of AFMR. Three kinds of crystallographic domains obtained from twining are established. Two magnon excitations may have also been observed. 相似文献
93.
2-Ureidoisocytosine bearing a phosphonium ion functionality self-assembles in an anti-parallel manner, to exhibit a cooperative acid/base catalysis for the ring-opening reaction of an epoxide. 相似文献
94.
Masahiro Endo Katsuaki Yamada Kenji Tadano Yoshikazu Nishino Shinichi Yano 《Macromolecular rapid communications》2000,21(7):396-400
Miscibility and crystallization behavior have been studied for polytetrafluoroethylene(PTFE)/poly(tetrafluoroethylene‐co‐2 mol‐% perfluoropropylvinyl ether)(PFA copolymer) blends by the use of differential scanning calorimetry, electron microscopy, X‐ray diffractometry and dynamic mechanical spectroscopy. In the amorphous phase, the two components were miscible with each other over all blending ratios, and it was found that the PFA copolymer was compatible with the PTFE matrix, when the PFA content is ≤ 50 wt.‐%, while PTFE was mixed in the PFA matrix when the PFA content is >50 wt.‐%. All the blends were crystalline as well as PTFE and PFA. The crystallization behavior was closely connected to the polymer composition of the amorphous state described above. It was conjectured that the crystallization is controlled by the PTFE matrix when the PFA content is ≤ 50 wt.‐%, while by the PFA matrix when the PFA content is >50 wt.‐%. 相似文献
95.
Takeo Oku Takanori Hirano Satoru Nakajima Katsuaki Suganuma Eiji Aoyagi Kenji Hiraga 《Molecular Crystals and Liquid Crystals》2013,570(1):799-804
Abstract Formation of carbon nanocapsules with various clusters (SiC, Au, Fe. Co. Ge. and GeO2) by polymer pyrolysis was investigated, and nanocapsules with SiC and Au nanoparticles were produced by thermal decomposition of polyvinyl alcohol at ?500°C in Ar gas atmosphere. The formation mechanism of nanocapsules and a structural model for the nanocapsule/SiC interface were proposed. In addition, carbon clusters were formed at the surface of carbon nanocapsules, and carbon onions were produced by electron irradiation of amorphous carbon produced from polyvinyl alcohol. The present work indicates that the pyrolysis of polymer materials with clusters is a useful fabrication method for the mass-production of carbon nanocapsules and onions at low temperatures compared to the ordinaly are discharge method. 相似文献
96.
New proton and electron donors, M(II)(HL)(2) (M = Ni, Pd, Pt; L = 5,6-diethylpyradzinedithiolate), as well as a proton and electron acceptor, Pt(IV)(L)(2), were prepared and characterized. The pH-dependent cyclic voltammetry of the M(II)(HL)(2) complexes revealed a favorable Gibbs free energy (K(com) > 1) for the proton and electron transfer reactions from M(II)(HL)(2) to M(IV)(L)(2); i.e., the equilibrium for the following reaction lies to the right: M(II)(HL)(2) + M(IV)(L)(2) <==>2M(III)(HL)(L). 相似文献
97.
Katsuaki Baba Dr. Mamoru Tobisu Prof. Dr. Naoto Chatani 《Angewandte Chemie (International ed. in English)》2013,52(45):11667-11667
98.
A Ni-catalyzed cross-coupling reaction of (Z)-5-(tert-butyldiphenylsilyl)oxy-3-bromo-1-trimethylsilyl-3-penten-1-yne (1) with alkyl Grignard reagent gives (Z)-3-alkyl-5-(tert-butyldiphenylsilyl)oxy-1-trimethylsilyl-3-penten-1-ynes (2) stereospecifically in good yields. The (Z)-enyne 2a is transformed in four steps to (Z)-3-methyl-5-silyloxy-3-pentenal (3), which is coupled with ketophosphonate 4 to give enone 13. The η-hydroxyallyl methanesulfonate derived from 13 is cyclized to 3,6-dihydro[2H]pyran by an intramolecular SN2′ reaction stereoselectively, furnishing a C17-C27 carbon unit of (−)-laulimalide. 相似文献
99.
Fujii S Kanaizuka K Toyabe S Kobayashi K Muneyuki E Haga MA 《Langmuir : the ACS journal of surfaces and colloids》2011,27(14):8605-8610
We have developed a new fabrication method for a ring structure of assembled nanoparticles on a gold surface by the use of continuous Nd:YAG laser light. A micronanobubble on a gold surface, created by laser local heating, acts as a template for the formation of the ring structure. Both Marangoni convection flow and capillary flow around the micronanobubble are responsible for the driving force to assemble nanoparticles such as CdSe Q-dots into the ring structure from the solution. Because a single micronanobubble was generated by the Nd:YAG laser focusing point, the precise positioning of the ring structure was feasible directly on the gold surface, which makes it possible to fabricate various patterns of rings such as arrays and letters and even a double-ring structure without any photomasks or any templates. 相似文献
100.
Konishi K Takase E Fukunaga N 《Langmuir : the ACS journal of surfaces and colloids》2011,27(4):1332-1335
A series of water-soluble cadmium sulfide clusters bearing an alkyl-chain layer between the inorganic core and the outer PEG layer were synthesized by the ligand-exchange reaction of Cd(10)S(4)(SPh)(12) with thiols functionalized by an N-(ω-PEGylated alkyl) amide moiety. The photoluminescence titration experiments in aqueous media revealed that clusters with a sufficiently hydrophobic inner environment exhibit definite emission enhancements upon the addition of bisphenol A or 4-nonylphenol. The dramatic effect of the alkyl chain length on the emission responses demonstrated that the hydrophobic layer around the inorganic surface serves as guest binding sites to facilitate the access of the lipophilic phenols near the organic-inorganic interface. A marked preference for the lipophilic phenols over related compounds, such as methylated bisphenol A, long-chain n-alkanol, and nonlipophilic phenols, was observed in the emission responses of the "hydrophobic" cluster, suggesting that not only the hydrophobic interaction but also the attractive force involving the phenolic OH group contributes to the positive responses. The results of control experiments and IR studies indicated that the hydrogen bonding interaction between the phenolic OH group and the amide group in the surface organic units is responsible for the positive emission responses. The present work shows that the precise tuning of the molecular recognition environments near the organic-inorganic interface is useful for developing guest-specific functions. 相似文献