972 resultados para 3-17-1


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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...

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In the structure of 4,10,16,22-tetraamino-6,12,18,24-tetramethyl-5,11,1 7,23-tetraaza-1,7,13,19-tetraazoniapentacyclo[19.3.1. 1(3,7).1(9,13).1(15,19)]octacosa-1(25),3,5,- 7(26),9,11,13(27),15,17,19(28),21,23-dodecaene dichloride dihydroxide octahydrate, C

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本文采用蒸发溶液法生长出一系列 Ce_xGd_(1-x)P_5O_(14)晶体,测定了它们的结构均属于单斜晶系、空间群 P2_1/c,用稳态和时间分辨荧光光谱法研究了该晶体中不同 Gd 含量时的发光性能,观察到随着(1-x)值增加,包含有 Gd~(3+)发射在内的314nm 峰增强和 Ce~(3+)的荧光寿命的有规律递减,说明了存在着 Ce~(3+)至 Gd~(3+)的能量传递。

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By the reaction of Cp3Ln (Cp = C5H5; Ln = Dy, Ho, Yb) with equimolar n-propyl alcohol in THF (tetrahydrofuran) at room temperature three new binuclear organolanthanide complexes, [CP2Ln(mu-OCH2CH2CH3)]2 (Ln = Dy, Ho, Yb), have been synthesized, as shown by X-ray single-crystal structure analysis for the complex [Cp2Yb(mu-OCH2CH2CH3)]2. All the complexes were characterized by elemental analysis, IR and MS spectra. The Yb2O2 unit is planar, and the ytterbium atom is coordinated by two Cp ring centroids and two oxygen atoms of two n-propyloxide ligands to form a distorted tetrahedral geometry. The average Yb-C (Cp) bond distance is 2.589(17) angstrom. The average Yb-O distance is 2.199(5) angstrom. The Yb-Yb separation [3.521(1) angstrom] indicates that no metal-metal interaction is present.

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The complex [Nd(L)(CH3CN)(CF3SO3)3] has been synthesized. Where L = 1-methyl-1, 4, 7, 10-tetraazacycldodecane. The crystal structure of the complex has been determined by a four-circle X-ray diffractometer to a final deviation factor B value of 0.0370 and R(w) value of 0.0385 respectively. The crystal is triclinic system, space group P1BAR with a = 0.8738(2), b = 1.2870(3), c = 1.2900(3) nm, alpha = 85.63(2), beta = 87.25(2), gamma = 78.30(2)-degrees, V = 1.41571 (60) nm3, Z = 2, D(c) = 1.92 g/cm3. The neodymium ion is eight-coordinated to forming a distorted square antiprism.

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研究了TiO_2-Ta_2O_5-Li_2O:Eu~3+体系,当化学通式为Ti_(1-4x-y)Ta_(3x)Li_xO_2:Eu_y~(3+),在0.1≤y≤0.25,0.05

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本文用高温固相扩散反应方法及坩埚下降法制备了KMgF_(3~-)Ce~(3+)及KMg_(1-x)M_xF_(3~-)Ce~(3+)(M=Be~(2+),Ca~(2+))的粉末样品及KMgF_(3~-)Ce~(3+)单晶,测定了它们的激发光谱和发射光谱,发现KMgF_(3~-)Ce~(3+)中存在两种不同的发射中心,且证明了这是不同的电荷补偿途径所致,而不是Ge~(3+)占据了不同的阳离子格位所致.通过X射线四圆衍射仪的检测及Be~(2+)和Ca~(2+)对KMgF_(3~-)Ce~(3+)中Mg~(2+)取代后的光谱变化,推断Ce~(3+)占据KMgF_3中K~+的格位.