955 resultados para 3-7-1


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Crystal structure and polymorphism induced by uniaxial drawing of a poly(aryl ether ketone) [PEDEKmK] prepared from 1,3-bis(4-fluorobenzoyl)benzene and biphenyl-4,4'-diol have been investigated by means of transmission electron microscopy (TEM), electron diffraction (ED), wide-angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC) techniques. The melting and recrystallization process in the temperature range of 250-260 degrees C, far below the next melting temperature (306 degrees C), was identified and found to be responsible for the remarkable changes in lamellar morphology. Based on WAXD and ED patterns, it was found that crystal structure of isotropic-crystalline PEDEKmK obtained under different crystallization conditions (melt-crystallization, cold-crystallization, solvent-induced crystallization, melting-recrystallization, and crystallization from solution) keeps the same mode of packing, i.e., a two-chain orthorhombic unit cell with the dimensions a = 0.784 nm, b = 0.600 nm, and c = 4.745 nm (form I). A second crystal modification (form II) can be induced by uniaxial drawing above the glass transition temperature, and always coexists with form I. This form also possesses an orthorhombic unit cell but with different dimensions, i.e., a = 0.470 nm, b = 1.054 nm, c = 5.064 nm. The 0.32 nm longer c-axis of form II as compared with form I is attributed to an overextended chain conformation due to the expansion of ether and ketone bridge bond angles during uniaxial drawing. The temperature dependence of WAXD patterns for the drawn PEDEKmK suggests that form II can be transformed into the more stable form I by relaxation of overextended chains and relief of internal stress at elevated temperature in absence of external tension.

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The net charges at atoms in the high-temperature superconductor TlBa2Can-1CunO2n+3 (n = 1 to 3) are calculated by means of the tight-binding approximation based on the EHMO method. The results indicate that the charge distribution in this kind of compounds possesses a specially layered arrangement. An insulating Ba-Ba layer is inserted between the Cu-O layer and the Tl-O layer. There may exist a weak coupling between the Cu-O layer and the Tl-O layer through the interaction of the same O(2) atom with both the Cu atom and the Tl atom. The existence of the Ca in the compounds can cause the valence fluctuation at the Cu atom. The calculated electric field gradients at atoms implies that the conducting electron or hole may move in the Cu-O layer, which is closest to the Tl-O layer, along the a-b plane.

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本文报道了用J-O理论计算的Er_(3x)~(3+):Y_(3-3x)A_5O_(12)和Er_x~(3+)Yb_(1-x)P_5O_(14)两种晶体中Er~(3+)五种浓度的振子强度、Ω_λ参数、辐射跃迁几率与荧光分支比。并观察了这些参数的变化规律。

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In the title compound, C12H11N7OS, the dihedral angles made by the thione-substituted triazole ring with the other triazole ring and the benzene ring are 71.56 (2) and 47.89 (3)degrees, respectively. Inter- and intramolcular hydrogen-bond interactions stabilize the structure.

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In the title compound, C12H10ClN7S, the dihedral angles made by the plane of the thione-substituted triazole ring with the planes of the other triazole ring and the benzene ring are 73.57 (3) and 46.65 (2)degrees, respectively. Inter-and intramolcular hydrogen bonds and pi-pi stacking interactions stabilize the structure.

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为了解高温高压条件下,α-β石英相变过程中的弹性性质,在0.7~1.8GPa,室温~1120℃条件下,利用多顶砧波速测量装置,采用脉冲反射-透射法,测量了α石英以及相变为β石英的纵波速度,弹性纵波穿过单晶α石英的方向为平行结晶轴X方向。实验结果表明,随温度升高,α石英的纵波速度开始非线性降低,之后,快速升高,这一现象是由于α-β石英相变引起的,依据晶体对称性与弹性参数的关系确定了α石英的弹性参数(C_(11)),及其随温度和压力的变化关系,同时获得了β石英的弹性参数(C_(11)),实验证实,测量α-β石英相变时的纵波速度,不仅是确定α-β石英相变温度和压力的一种方法,也是校正高压腔体温度和压力的有力手段.

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Children’s understanding of deontic rules and theory of mind (ToM) were the two research domains for children’s social cognition. It was significant for understanding children’s social cognition to combine the researches in the two domains. Children at 3, 5 and 7years were required to answer three questions according to the stories which happened in children’s familiar context. The three questions were designed to address the three problems:⑴Development of 3-7-Year-old children’s understanding about how the deontic rules were enacted or changed.⑵ Development of 3-7-Year-old children’s understanding about that the deontic rules and the actor’s mental states could impact on his behaviors.⑶ Development of 3-7-Year-old children’s capacity to integrate the deontic rules and mental state to evaluate the actor’s behavior. The results showed that: ① The 3-7-Year-old children had known that deontic rules were established by the authority’s speech act. But there were still some irrelevant factors which influenced the children’s judgments, such as the authority’s desire. ② The children gradually recognized the relationship between actors should do something and they will do the same thing. 3-year-old children could recognize such relationship in a way, but their predictions were usually influenced by some irrelevant factors. The children at 5 and 7 years old understood this relationship more steady. ③ In deontic context, more and more children predicted the actors’ behaviors according to the actors’ mental states as they grown up. The ratio that the 3-7-Year-old children predicted the actors’ behavior according to their false belief about the deontic rules was smaller in deontic context compared with the children’s performance in traditional false belief task. This maybe indicated that the deontic context influenced the children’s inference stronger than the physical context. ④ When they could get the actors’ desires and the deontic rules, all the children could predict the actors’ behaviors according to their desires, but not the deontic rules. It meant that all the children could understand that the actors’ desire mediated between the deontic rules and their behaviors. But when the actors wanted to transgress the deontic rules, all the children’s predications became less accurate. ⑤ When they assigned criticism, more and more children could discriminate different behaviors as a result of diverse mental states although they all transgressed the deontic rules. But the most part of children overweighed the deontic rules but overlooked the actors’ mental state about the deontic rules; their criticism to behaviors which transgressed the deontic rules just differ in quantity according to diverse mental states, that is: if the actors known the rules or want to transgress the rules, then punished more, and if the actors didn’t know the rules or transgress the rules accidentally, then punished a little.

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A worker developed angiosarcoma, porphyria cutanea tarda, and skin lesions characteristic of mild chloracne. About 10 years earlier he had been employed at a truck terminal in Saint Louis, Missouri, at a time when it was sprayed with waste oil contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The occurrence of these three rare conditions in a single exposed worker supports the aetiological relation between environmental exposure to TCDD and the subsequent development of soft tissue sarcoma and porphyria cutanea tarda.

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The Knoevenagel condensation of 1,3-dihydro-2H-indol-2-one with ferrocene carboxaldehyde afforded an approximate 2:1 mixture of the geometrical isomers (E)- and (Z)-3-ferrocenylmethylidene-1,3-dihydro-2H-indol-2-one respectively in an overall 67% yield; the air and solution-stable isomers were readily separated by preparative thin layer chromatography and their structures were unequivocally elucidated in solution, by (1)H NMR spectroscopy, and in the solid phase, by X-ray crystallography; both isomers of displayed in vitro toxicity against B16 melanoma and Vero cell lines in the micromolar range and inhibited the kinase VEGFR-2 with IC(50) values of ca. 200 nM.

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Rh-2(cod)(2)(mu(2)-dppm)(mu(2)-Cl)]BF4 (1) rearranges under carbon monoxide to give [Rh-3(mu(2)-dppm)(2)-(mu(2)-CO)(3)(K-1-CO)(3)]BF4 (2). Complex 2 has been structurally characterized by single crystal X-ray crystallography. The hydroformylation activities of 1 and 2 were compared for substrates styrene and 1-hexene and the activity of 2 found to be unexpectedly high.

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Five new compounds in the system (NH4)Cl/HgCl2/H2O have been obtained as colourless single crystals, (NH4)Hg5Cl11, (NH4)(2)Hg3Cl8(H2O), (NH4)(4)Hg3Cl10(H2O)(2), (NH4)(2)HgCl4(H2O), and (NH4)(10)Hg3Cl16. In all of these, as in HgCl2 itself, (almost) linear HgCl2 molecules persist with Hg-Cl distances varying from 229 to 236 pm. In (NH4)(10)Hg3Cl16 there are also tetrahedra [HgCl4] with d(Hg-Cl) = 247 pm present. If larger Hg-Cl distances (of up to 340 pm) are considered as belonging to the coordination sphere of Hg-II, the structures may be described as consisting of isolated octahedra and tetrahedra as in (NH4)(10)Hg3Cl16, edge-connected chains as in (NH4)(2)HgCl4(H2O), edge-connected chains and layers of octahedra as in (NH4)(4)Hg3Cl10(H2O)(2), corrugated layers of edge-connected octahedra as in (NH4)(2)Hg3Cl8(H2O), and, finally, a three-dimensional network of connected six- and seven-coordinate Hg-Cl polyhedra as in (NH4)Hg5Cl11. The water molecules are never attached to Hg-II. The (NH4)(+) cations, and sometimes Cl- anions, play a role for electroneutrality only.