1000 resultados para Gamaline-V
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丙烷氧化反应中多组分氧化物Bi-V-Mo-O催化作用的红外光谱研究李静,宋伟,窦伯生(中国科学院长春应用化学研究所长春130022)关键词钼钒酸铋,丙烷,选择氧化,催化作用机理,红外光谱迄今对于含有钼、铋复合氧化物催化剂的活性中心和作用机理存在不同看...
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A new series of fully aromatic thermotropic liquid crystalline copolyesters were synthesized by thermal polycondensation of p-hydroxybenzoic acid (PHB), terephthalic acid (TPA), resorcinol (RES) and bis (4-hydroxyphenyl) methanone (BHP). The DSC traces of copolyesters exhibited two or three endotherms, the low temperature endotherm(Tm) of which indicated the transition from solid state to anisotropic phase. Observation under polarizing microscope and WAXD measurements suggested that the LC-phase formed immediately above Tm had a nematic character.
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X-ray diffraction and electrical and diamagnetic analyses revealed that the 2223 phase was significantly enhanced by high-valence cation (V5+, Nb5+, Ta5+, etc.) doping in BiSrCaCuO samples. The optimum nominal composition was Bi1.6M0.4Sr2Ca2Cu3 O(y)(M =
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Oxochromium (V) tetraphenylporphyrin complexes, O = Cr (V) TPP (Cl) PhI. O = Cr-(V) TPP (N3) PhI and O = Cr (V)TPP (p-CH3OC6H4O)1/2PhI were isolated from the reaction of Cr (III) TPP (Cl). Cr (III) TPP (N3) Py or Cr (III) TPP (p-CH3OC6H4O) THF with iodosy
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氮气保护下二氯甲烷中铬(Ⅲ)四苯基卟琳衍生物在-40℃与亚碘酰苯反应,分离得氧配位铬(V)四苯基叶啉配合物:O=Cr(V)TPP(CI)PhI,O—Cr(V)TPP(N_3)PhI,O—Cr(V)TPP(p-CH_3O-C_6H_4O)1/2PhI.已经元素分析、可见、红外、顺磁、核磁和质谱法结构表征.这些配合物能氧化苯乙烯,环己醇,环己烯和环己烷,可作为细胞色素P—450模拟体系的活性中间体.
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With XRD, R- T curves, and a.c chi measurements, the doping and codoping effects of Sb and V to a Cu-deficient Pb-doped Bi system have been studied. A sample singly doped with V possesses a T(c) about 2 K lower than that of a sample singly doped with Sb. This is attributed to the different sites of their substitution. It was observed that for promoting 2223 phase formation, Sb and V works cooperatively, and the codoping of Sb may enhance the 2223 phase formed. With a low doping level of Sb, the optimum doping amount of V is 0.3, i.e., with a nominal composition of Bi1.5Pb0.3Sb0.06Sr2Ca2Cu2.4V0.3Oy. A sample in which the 2223 phase is the dominant phase and which has a zero resistance transition temperature of 105 K has been obtained.
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考察了不同组成的V-Sb-O系复合氧化物对丙烷氨氧化的催化活性.用XRD研究了催化剂的结构,利用程序升温方法研究了催化剂中氧的活动性和表面酸碱性,讨论了催化剂体相和表面结构与催化性能间的关系.结果表明,VSbO_4和Sb_2O_4间的协同作用是影响催化活性的重要因素.
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The half-open vanadocene, V[2,4-(CH3)2C5H5](C5H5)CO, was obtained by the reaction of V[2,4-(CH3)2C5H5](C5H5)PMe3 with CO in petroleum ether at room temperature. Its crystal structure was determined by X-ray diffraction technique. The crystal was monoclinic with space group P2(1)/n, a = 16.614(3), b = 7.636(1), c = 19.128(6) angstrom, beta = 99.92(2)-degrees, V = 2390.5(9) angstrom3, and Z = 8. The final R value was 0.043. The V(1)-CPD(1) (half) (PD = 2,4-(CH3)2C5H5) bonds were shorter (0.038 angstrom) than the V(1)-CCP(1) (half) (CP = C5H5) bonds, averaging 2.224(4) versus 2.262(4) angstrom, respectively. 4V[2,4-(CH3)2C5H5](C5H5)CO has been characterized by IR and EPR methods.
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β,β-二烷硫基-α,β-不饱和酮类化合物作为一类具多反应中心的活泼中间体在有机合成中的应用,近20年来已引人注目并进行了深入广泛的研究~[1,2].以往的研究大多是针对β,β-二甲硫基-α,β-不饱和酮类化合物1进行的,而对结构相近的β,β-1,3-亚丙二硫基-α,β-不饱和酮类化合物2的研究较少.对于1类的合成,所用碱的选择至关重要~[1].实验证明叔丁醇钠和叔丁醇钾~[3~5]在1类的合成中效果较好.前文~[6]曾以六甲基二硅氨基锂(LHMDS)为碱高
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自发现BiSrCaCuO超导体以来,为了稳定2223高T_C相结构、增加其在超导体中的含量,在该体系中引入掺杂元素Pb被公认是最有效的方法。我们系统研究了V~(5+)、Nb~(5+)、Ta~(5+)高价离子的单独掺入Bi系中对
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本文通过透射电子显微镜,扫描电子显微镜研究了聚甲基丙烯酸胆甾接枝共聚物室温结晶态的微细结构,及胆甾侧链含量对结晶的影响。
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Aims: To investigate the species-specific prevalence of vhhP2 among Vibrio harveyi isolates and the applicability of vhhP2 in the specific detection of V. harveyi from crude samples of animal and environmental origins. Methods and Results: A gene (vhhP2) encoding an outer membrane protein of unknown function was identified from a pathogenic V. harveyi isolate. vhhP2 is present in 24 V. harveyi strains isolated from different geographical locations but is absent in 24 strains representing 17 different non-V. harveyi species, including V. parahaemolyticus and V. alginolyticus. A simple polymerase chain reaction method for the identification of V. harveyi was developed based on the conserved sequence of vhhP2. This method was demonstrated to be applicable to the quick detection of V. harveyi from crude animal specimens and environmental samples. The specificity of this method was tested by applying it to the examination of two strains of V. campbellii, which is most closely related to V. harveyi. One of the V. campbellii strains was falsely identified as V. harveyi. Conclusions: vhhP2 is ubiquitously present in the V. harveyi species and is absent in most of the non-V. harveyi species; this feature enables vhhP2 to serve as a genetic marker for the rapid identification of V. harveyi. However, this method can not distinguish some V. campbellii strains from V. harveyi. Significance and Impact of the Study: the significance of our study is the identification of a novel gene of V. harveyi and the development of a simple method for the relatively accurate detection of V. harveyi from animal specimens and environmental samples.