258 resultados para 3-17-1


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通过计算机辅助方法对1 3 CNMR化学位移进行预测 .这个方法包括分子拓扑指数和几何参数特征值的计算及对所选特征进行的变量压缩 ,并对所选共振碳的化学位移与其提取的特征进行多元回归分析 ,从而得出其相关数学模型 .本文预测了环己烷中 45个仲碳原子的1 3 C化学位移 ,其标准误差约为 1 .4ppm.

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采用 (C9H7) 2 Y( μ Et) 2 AlEt2 为单组分催化剂或其与三异丁基铝 [Al(i Bu) 3]组成的催化体系 ,研究了甲基丙烯酸甲酯的聚合规律 .前一配合物单独可使甲基丙烯酸甲酯聚合 ,获得分子量可达 34 0万 ,全同含量达 93%的聚合物 ;后一催化体系可使甲基丙烯酸甲酯聚合 ,获得分子量大于6 0万 ,间同含量达 6 5 %的聚合物.

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(2,4-C7H11)(2)Yb . DME was synthesized by the reaction of YbCl3 with K(2,4-C7H11)(2,4-dimethylpentadienyl potassium), and the single crystal X-ray diffraction showed that the complex exists in a cis- staggered conformation. Thf crystal of the compound belongs to the monoclinic space group P2(1)/n with a = 0.675 2 (1) nm, b = 1.490 6 (1) nm, c = 1.529 3 (2) nm, beta = 97.55 (2)degrees, V = 1.977 79 (4) nm(3), Z = 4, F(000) = 735.8 e, mu = 49.49 cm(-1), R = 0.033 and R-w = 0.032. The title complex can be used as a catalyst for the polymerization of methyl methacrylate (MMA).

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分别研究了三价稀土离子、稀土离子和钙调蛋白CaM的复合物以及作为稀土离子配体的二乙三胺五乙酸DTPA及其衍生物二乙三胺五乙酸双二甲酰胺 DTPABDMA和二乙三胺五乙酸双异烟肼DTPABIN对乳酸脱氢酶LDH活性的影响。结果表明稀土离子浓度小于3μmol·L-1时对酶活性具有轻微的激活作用离子浓度增大到6μmol·L-1后则开始表现出抑制作用钙调蛋白可以缓解这种抑制作用二乙三胺五乙酸及其衍生物在浓度超过5μmol·L-1 时对酶活性均有抑制这种抑制作用在加入外源的钙调蛋白后也得到缓解。

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用溶胶 -凝胶法合成了 Ce1-x Cax O2 -x(x=0~ 0 .3 5 )系列固体电解质 ,系统地研究了其晶体结构随Ca O含量的变化关系 .XRD测试表明 ,该体系于 1 60℃即形成萤石结构纯相 .高温 XRD表明 ,从室温至80 0℃ ,Ce1-x Cax O2 -x(x=0~ 0 .3 5 )未出现结构相变 .此法合成温度远低于传统的高温固相合成法和水热合成法的温度 .合成物的颗粒小 ,粒度均匀 .在 1 3 0 0℃即可烧结成高致密度样品 .XPS测试表明 ,掺杂 Ca O后吸附氧浓度明显增大 ,氧空位增多 ,电导率和氧离子迁移数增大 ,改善了 Ce O2 基固体电解质的性能 .

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Optically active (R)-(+)-2, 2'-bis(2-trifluoro-4-aminophenoxy)-1, 1'-binaphthyl was prepared from 1, 1'-bi-2-naphthol. The optically active aromatic polyimide was also successfully synthesized. This new polymer has good solubility, thermal stability etc. Its specific rotation was found to be +174 degrees, and its chiroptical property was also studied.

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通过测定 4 5Ca2 +摄取初速度的变化研究了La3+和Gd3+对鼠肝癌H 3 5细胞Ca2 +内流的影响 .发现低浓度La3+和Gd3+能增加肝癌H 3 5细胞Ca2 +内流初速度达 6~ 10倍 .Ca2 +内流的初速度随Ca2 +浓度变化的动力学研究表明 ,肝癌H 3 5细胞中存在 2类Ca2 +亲和部位的通道 ,即高亲和位和低亲和位Ca2 +内流通道 ,而La3+和Gd3+刺激的肝癌H 3 5细胞则只有 1类Ca2 +亲和位通道 ,La3+和Gd3+增加高亲和位Ca2 +结合通道的Km和Vmax,而对于低亲和位的Ca2 +结合通道Ca2 +内流的作用是竞争性的.

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利用平衡透析、原子吸收、荧光滴定和荧光寿命测定等方法确定了皖南尖吻蝮蛇蛇毒纤溶组分(FP)中Ca(2+)含量,并利用荧光光谱研究了Tb(3+)与FP中色氨酸(Trp)残基之间能量转移和FP中的微区结构。结果表明,每个FP分子中只含有一个Ca(2+);Tb(3+)可完全取代FP中的Ca(2+),FP中的Trp残基可将能量转移到结合在FP中的Tb(3+)上;研究还测得Tb(3+)与FP中Trp残基之间的距离约为0.375nm。

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采用高温固相反应法,合成了CaAl2B2O7:Eu磷光体。测定了CaAl2B2O7:Eu的振动光谱,结果表明BO3的振动吸收位于1400~1600cm(-1)区域内,AlO6的吸收位于519cm-1。研究了CaAl2B2O7:Eu中Eu(3+)的光谱特性,发现两个不同的Eu(3+)的发光中心。声子伴带研究表明BO3出现在Eu(3+)的周围。

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采用直接熔融缩聚方法由1,6-己撑-双(4-羟基酞酰亚胺)(BHPI)、对羟基苯甲酸(PH-BA)和对苯二甲酸(TPA)合成一系列三元共聚酯酰亚胺。对聚合物进行示差扫描量热(DSC)、偏光显微镜(PLM)、广角X-射线衍射(WAXD)等分析表征,结果表明该系列聚合物具有向列型液晶特征。

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应用介电描述的复杂晶体化学键理论,给出计算Ni2+和Er3+在固体中的电子云扩大效应的新方法.

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Pr~(3+)离子的能级结构丰富,在紫外可见区有很好的荧光发射。因此,以Pr~(3+)为激活离子的发光材料研究工作引起了人们的关注。轻稀土五磷酸盐晶体结构为单斜晶系,空间群为P_(1/2)/C,稀土离子处在隔离的多面体中,离子间的作用减弱,即使在化学计量比的PrP_5O_(14)仍得到激光输出。本文采用水热法生长出La_(1-x)Pr_xP_5O_(14)

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采用喷涂热解法制备了以Cd2SnO4为代表的四种半导体薄膜,即Cd2SDO4,In2SnO5,TiSnO4及Zn2SnO4。测试了薄膜的半导体、光学和电学性能,得到了In2SnO5,Cd2SpO4薄膜电阻率的范围在10(-3)Ω·cm和高的透射比(可见光);TiSnO4薄膜高的反射比(红外光);同时,比较溅射法对结果进行了讨论。

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Dinuclear complexes [Mo-2(mu-pyS)(2)(CO)(4)(PPh(3))(2)] (1), [Mo-2(mu-pyS)(2)(CO)(5)(PPh(3))] (2) and a trace quality of trinuclear complex [Mo-3(mu-pyS)(2)(mu(3)-pyS)(2)(CO)(6)] (3) were obtained from the reaction of [Mo(CO)(3)(MeCN)(3)] with pyridine-2-thione (pySH) and PPh(3) in THF. The crystal structures of 1.2C(7)H(8) and 3.7 C7H8 have been determined by X-ray diffraction studies. Crystals of 1.2C(7)H(8) are monoclinic, space group C2/c and Z = 4, with a = 18.797(3), b = 11.143(4), c = 28.157(7) Angstrom, beta = 101.23(2)degrees. The structure was refined to R = 0.050 and Rw = 0.057 for 3146 observed reflections, Crystals of 3.7 C7H8 are monoclinic, space group P2(1)/a and Z = 4, with a = 13.912(2), b = 17.161(2), c = 15.577(3) Angstrom, beta = 101.17(1)degrees. The structure was refined to R = 0.046 and Rw = 0.051 for 4357 observed reflections. The molecule of 1 consists of two Mo(CO)(2)(PPh(3)) fragments linked by an Mo-Mo bond (2.974(2)Angstrom) and by two doubly-bridging pyS ligands. The compound 3 contains a bent open geometry of three molybdenum atoms (Mo(1)-Mo(2)-Mo(3) angle 122.99(3)degrees) linked by two Mo-Mo bonds (2.943(1) and 2.950(1) Angstrom) and by two doubly- and two triply-bridging pyS ligands.

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乙基苯基二氯化锡与2-羟基萘醛缩对甲氧基苯胺Schiff碱1∶1配合物的合成和晶体结构刘宝殿,包明,孙振刚,贺庆林,邢彦,贾恒庆,林永华(东北师范大学化学系,长春,130024)(中国科学院长春应用化学研究所,长春)关键词乙基苯基二氯化锡,Schif...