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81.
Heat contents of the PbS system were measured by a drop calorimeter in the composition range of sulfur Xs = 0 to 0.5 (PbS) and in the temperature range of 560 to 1500 K, and a heat content-temperature-composition ternary diagram was constructed. By using a quantitative thermodynamic analysis method, free energy, heat and entropy of mixing in the liquid PbS binary and PbPbS pseudo-binary systems were derived from the measured heat contents. The obtained partial molar free energies of mixing (activities) are considerably different from those estimated by the use of a regular solution model. 相似文献
82.
Kōichi Mikami Toshihiko Maeda Naoyuki Kishi Takeshi Nakai 《Tetrahedron letters》1984,25(45):5151-5154
An enantiospecific synthesis of the title compound is described which involves the TiCl4-promoted cyclization of the chiral allylic silane having formyl group, which was obtained via the Claisen rearrangement of (, )-1-trimethylsilyl-1-buten-3-ol. 相似文献
83.
Toshiyuki Iida Joji Ohshita Taisuke Uemura Hiroshi Fukuoka Nobuaki Ohta Kenji Komaguchi Yoshiteru Itagaki Masaru Shiotani Shoji Yamanaka Atsutaka Kunai 《Silicon Chemistry》2002,1(5-6):383-389
The spin states of a series of silicon- and carbon-bridged phenyl nitroxides were examined with respect to the temperature dependent ESR and SQUID measurements. Of those, a linear relationship between the ESR signal intensity and 1/T (T = absolute temperature) and an increase of χmolT along lowering T were observed for a compound having disilanylene-bridged m- and p-phenyl nitroxide units (Si2mp), indicating ferromagnetic spin-spin interaction in this molecule. In contrast to this, no clear intramolecular spin-spin interaction took place in the monosilanylene analogue (Si1mp). Mono- and disilanylene-bridged phenylnitroxides with p-, p- or m-, m-substitution (Si1pp,Si1mm, Si1pp, and Si2mm) exhibited the singlet ground state. The trisilanylene and siloxanylene bridges did not play an obvious role in the spin interaction, in either a ferro- or antiferromagnetic fashion, regardless of the substitution modes of the phenylenes. MO calculations on the model compounds provided a mechanistic interpretation for the high-spin interaction through the σ-π system. 相似文献
84.
In the presence of zeolites, moderately deactivated arenes such as 1-nitronaphthalene, naphthonitriles, and methylated benzonitriles can be smoothly nitrated at room temperature by the combined action of nitrogen dioxide and molecular oxygen. The regioselectivity is considerably improved as compared with the conventional nitration methodology based on nitric and sulfuric acids. In some cases, the minor isomer became favoured to a significant extent, resulting in the reversal of ordinary isomer ratios of nitration products. 相似文献
85.
Yasuo Koma Naoyuki Koide Akira Tanaka Kazuyoshi Iimura Masatami Takeda 《Journal of polymer science. Part A, Polymer chemistry》1979,17(2):465-471
The complex of acrylonitrile (AN) with trimethylaluminum (AlMe3) was successfully isolated as a white needlelike crystal with a melting point of 42.5°C. In this article the preparation of the complex is described in detail. Cryoscopic and spectral investigations indicated that the complex is formed by an equimolar ratio of AN and AlMe3. From the measurement of the x-ray diffraction photograph of the crystal the repeat period was determined to be 9.47 ± 0.05 Å. 相似文献
86.
The intermediates in the reactions of 2,4-dinitro-(2) or 2,4,5-trinitro-1-naphthyl ethyl ether (11) with secondary amines have been studied. In the reaction of 2 with piperidine, the NMR spectrum of the reaction system indicated the coexistence of the three species-starting material, Meisenheimer complex, and substituted product. In the reaction of 11 with piperidine or N-methyl-n-butylamine, the the NMR spectra of the reaction system indicated the presence of a Meisenheimer complex, but did not indicate the formation of a substituted product. In addition, the spiro Meisenheimer complex (9) was prepared from 1-[N-methyl-(2′-hydroxy)ethylamino]-2,4,5-trinitronaphthalene (8) and sodium methoxide. 相似文献
87.
88.
89.
In this article, we consider the maximum cocliques of the 211: M24 ‐graph Λ. We show that the maximum cocliques of size 24 of Λ can be obtained from two Hadamard matrices of size 24, and that there are exactly two maximum cocliques up to equivalence. We verify that the two nonisomorphic designs with parameters 5‐(24,9,6) can be constructed from the maximum cocliques of Λ, and that these designs are isomorphic to the support designs of minimum weights of the ternary extended quadratic residue and Pless symmetry [24,12,9] codes. Further, we give a new construction of Λ from these 5‐(24,9,6) designs. © 2009 Wiley Periodicals, Inc. J Combin Designs 17: 323–332, 2009 相似文献
90.
Koji Ishizu Naoyuki Kobayakawa Satoshi Takano Yoko Tokuno Masaaki Ozawa 《Journal of polymer science. Part A, Polymer chemistry》2007,45(9):1771-1777
The crosslinked polystyrene particles possessing photofunctional N,N‐diethyldithiocarbamate groups on their surface were prepared by free‐radical emulsion copolymerization of a mixture of styrene, divinylbenzene and 4‐vinylbenzyl N,N‐diethyldithiocarbamate with redox system as an initiator under UV irradiation. In this copolymerization, the inimer 4‐vinylbenzyl N,N‐diethyldithiocarbamate acted the formation of hyperbranched structures by living radical photopolymerization. The particle sizes (number‐average particle diameter = 214–523 nm) were controlled by varying the feed amount of surfactant and size distributions were relatively narrow. Subsequently, core–shell particles were synthesized by photoinduced atom transfer radical polymerization approach of methyl methacrylate initiated by photofunctional polystyrene particles as a macroinitiator. Such core–shell particles were stabilized sterically by grafted chains in organic solvents. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1771–1777, 2007 相似文献