990 resultados para 320-U1332
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提出了一条合成还原态的苯基封端聚苯胺齐聚物的新方法 :即苯胺二聚体的 Schiff碱或苯胺三聚体的 Schiff碱在酸性溶液中缓慢水解 ,形成聚苯胺二聚体和三聚体的盐酸盐 ,这些盐酸盐与二苯胺或 N-苯基 -对苯二胺反应 ,经苯肼还原 ,生成还原态的苯基封端的聚苯胺三聚体和四聚体 .用红外、核磁、元素分析和基底辅助激光解吸质谱对其进行了表征 ,并用紫外光谱对还原态的三聚体和四聚体的化学氧化过程进行了跟踪研究
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The homoepitaxial crystallization in the films of a thermotropic liquid crystalline chloro-ply(aryl ether ketone) is studied by transmission electron microscopy (TEM) and electron diffraction (ED). The homoepitaxy takes place in the temperature range 330-320 degreesC, in which a highly-ordered smectic crystalline phase of the copolymer with a single-crystal-like banded structure is formed during the cooling process from the isotropic melt. The homoepitaxial crystallizations with angles of 32 degrees and 122 degrees between the two b axes are the major populations observed, and possess epitaxial contact planes of (100)(I)-(210)(II) and (010)(I)-(210)(II); respectively.
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在 N,N-二甲基甲酰胺(DMF)存在下,研究了钛酸丁酯的水解缩聚过程,考察了酸及 DMF用量对水解速率的影响。结果表明,随酸和 DMF用量的增加,胶凝时间变长。通过 TG-DTA的测定和X射线衍射分析,表明TiO2胶粉末在500℃时已转变成锐钛矿结构,600℃时锐钛矿与金红石结构两相并存,到800℃时全部转化为金红石结构。
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Poly(phenylenesulfidephenylenamine)(PPSA) an alternating copolymer and the hybrid structure of poly(phenylene sulfide)(PPS) and polyaniline(PAn), was synthesized by self-polycondensation of methyl-(4-anilino-phenyl) sulfide with antimony pentachloride and by the acid-induced self-polycondensation of methyl-(4-anilino-phenyl) sulfoxide.
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Half-sandwich nitrosyl complexes Cp*M(NO)I-2 (M = Mo, or W) react with dithiocarbamates (NaS2CNMe2 and NaS2CNEt2) in THF to form of complexes: Cp*Mo(NO)I (S2CNMe2) (1), Cp*Mo(NO)I(S2CNEt2) (2), Cp*W(NO)I(S2CNMe2) (3) and Cp*W(NO)I(S2CNEt2) (4) in high yields. Treatments of Cp*M(NO)I-2 (M = Mo, W) or [CpMo(NO)I-2](2) with phosphinodithioate (NaS2PMe2) and phosphorodithioate [(NH4)S2P(OMe)(2)] result in complexes: Cp*Mo(NO)I(S2PMe2) (5a), CpMo(NO)I (S2PMe2) (5b), Cp*Mo(NO)(S2PMe2)(2) (6a), CpMo (NO) (S2PMe2)(2) (6b) and Cp*Mo(NO)I[S2P(OMe)(2)] (7), Cp*W(NO)I(S2PMe2) (8), Cp*W(NO) I[S2P(OMe)](2) (9). Treatment of (5a) and (5b) with an excess of NaS2PMe2 gives (6a) and (6b). The complexes have been characterized by their elemental analyses, i.r., H-1, C-13-n.m.r. and by EI-MS spectrometry.
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Three organo-soluble polyimide powders have been synthesized. Their imidization was verified by Fourier transform infrared (FTIR) and thermal gravimetric analysis (TGA) techniques. The amorphous morphology of their thin films were confirmed by X-ray diffraction. Polyimide thin films were prepared by solution casting or spin coating. UV-visible transmission spectra of thin films revealed that they are almost transparent in the range of visible light. With in-plane orientation, revealed by FTIR spectra, negative birefringence (Delta n) of thin films were observed, and refractive indices of the thin films along the film plane (n(TE)) and normal to the plane (n(TM)) were measured by a prism coupler. Because of negative birefringence of the thin films, they tan be substituted for the compensation films for twisted nematic liquid crystal displays (TN-LCDs) to extend their viewing angles. In this paper, a 90 degrees C TN-LCD and 120 degrees C TN-LCD were taken as examples to show the compensation effect of thin films of a qualified polyimide. (C) 1998 Elsevier Science S.A. All rights reserved.
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根据电感耦合等离子体原子发射光谱(ICP-AES)分析的实际需要,开发了一种ICP-AES分析信息系统。该系统包括谱线管理系统、识别干扰程度系统、校准及干扰校正系 统、帮助系统等子系统。本文将讨论系统分析。系统设计和系统评价将在另文中讨论。
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The luminescence properties of Ce3+, Gd3+, and Tb3+ have been investigated in the compound CaAl2B2O7. The single excitation band peaking at about 320 nm and single emission band peaking at about 384 nm for Ce3+, without the characteristic doublet, are attributed to the extensive crystal-field splitting of 4f ground state. The emission of Gd3+ consists of well-known sharp lines and two weak bands around 319.5 and 325 nm. These bands are due to the coupling of Gd3+ with BO33- groups. The green emission of Tb3+ is considerably sensitized by Ce3+. Energy transfer from Ce3+ to Tb3+ in CaAl2B2O7 is efficient. (C) 1997 Elsevier Science Ltd.
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Ce:Nd:LiNbO3晶体具有优良的光折变性能,它作为全息记录介质,用于实现了光学图象微分和全息关联存储。
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采用WAXD、DSC、POM、SEM和力学测试方法研究了LC70/PET原位复合材料的结构与性能。结果表明,当LC70/PET<20%时,LC70对PET的结晶生长具有一定促进作用;当LC70/PET>30%时,共混物结晶能力迅速下降,结晶放热和熔融焓明显降低。LC70可起到加速成核作用。LC70与PET部分相容,在较高LC70含量下的SEM观察表明,存在清晰的“皮-芯”结构。
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In this paper, based on the consideration of covalent behavior of adjacent ions in crystals, a calculation formula of lattice energy was proposed. In which, the concept of ionic effective valence and the empirical formula covalent energy were introduced,
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我们在考虑了晶体中近邻正、负离子的共价行为的基础上,提出了晶体点阵能的计算公式,并引进了离子有效价态的概念和共价能计算的经验表达式,把二元离子晶体点阵能的计算推广到一般极性共价晶体和其他复杂晶体,计算结果与实验结果符合得很好.
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克山病是一种以心肌坏死为主的地方性心肌病,病因尚不清楚。本项研究由云南、西藏、吉林三个省(区)共采集克山病患者心肌19例(其中慢型克山病7例,亚急型克山病12例),非克山病的其他疚病患者心肌5例,同时还由吉林省非克山病区采集急死的健康人心肌43例做对照,完成了直接对克山病的主要受累靶组织-心肌19种元素含量的对照研究。此外,还通过三批动物实验(共用动物320只)对心肌元素及其代谢特点、心肌
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结晶-非晶高聚物共混体系的相容性和结晶行为的研究已有许多报道。本工作研究了含酞侧基聚芳醚酮(PEK-C)与聚苯硫醚(PPS)共混物的相容性和结晶行为。 PEK-C为徐州工程塑料厂产品,未作封端处理,η?p/c=0.70;PPS为日本东丽产品。两者用双螺杆挤出机在320~350℃制成共混物。仪器为Perkin-Elmer DSC-7型差示扫描量热仪,升温速率10℃/min;DDV-Ⅱ-EA型全自动动态粘弹谱仪和理学D/max-ⅡBX-射线衍射仪。
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本文报道注射级酞侧基聚芳醚砜(PES-C)和聚芳醚酮(PEK-C)共混试样的玻璃化转变行为和部分力学性能的研究结果。并讨论共混工艺对相容性的影响。 PES-C和PEK-C树脂均由中国科学院长春应用化学研究所徐州工程塑料厂合成,在三氯甲烷中的比浓粘度ηsp/c(20℃)分别为0.45和0.47。将粉状树脂在GH-100Q高速搅拌器内按配方混合,并在烘箱内干燥后,用SHJ-30双螺杆挤出机在320~350℃(物料温度)挤出造粒。