970 resultados para Aeneas, Tacticus, 4th cent. B.C.
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Rare earth complex (C5H9C9H6)(3)SmCl-Li+ (THF)(4)( I ) was synthesized by reacting anhydrous SmCl3 with two equivalents of C5H9C9H6Li. From mix-solvent of THF and hexane, red color single crystals were obtained. The crystal belongs to a cubic system, space group P2(1)3 with unit cell parameters a= b=c= 1. 754 0(2) nm, alpha=beta=gamma=90degrees, V=5. 396 4(11) nm(3), Z = 4. The ten-coordinated samarium atom is bonded to three cyclopentylindenyl rings and a chlorine atom to form the anionic part of the title complex, ring centroids and the chlorine atom form a tortured tetrahedron around samarium. In the cationic part, lithium atom coordinates to four oxygen atoms of THF molecules to form a normal tetrahedron. The Sm-C(within the same ring) distance varies from 0. 268 to 0. 299 nm.
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对环化丁苯橡胶的1 H 核磁共振谱进行了归属分析 ,并推导出计算环化度和溶剂参与量的公式。设环化丁苯橡胶的1 H 核磁共振谱图中化学位移为 7 0 ,5 4,4 9和 3 0~ 0处的峰强度分别为A ,B ,C和D ,则环化丁苯橡胶中丁二烯总物质的量 (X) =(B +C +D - 2A) /7 1 ,未环化的丁二烯物质的量 (Y) =B/2 +C/4,参与反应的二甲苯物质的量 (Z) =( 1 7 5A -B -C -D) /46 5,环化度 (P) =1 -Y/X ,溶剂参与量 (W ) =91 6Z/X。
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合成了八-4-(正壬氧基)酞菁铽(Ⅲ)(A)、八-4-(四氢糠氧基)酞菁(Ⅲ)(B)、双酞菁铽(Ⅲ)(C)、八-4-硝基酞菁铽(Ⅲ)(D),并通过元素分析、红外光谱、质谱和紫外.可见光谱加以确认。配合物B的π-A曲线表明它有很好的成膜性,Y型沉积形成的LB膜材料有很强的荧光响应,随着LB膜厚度的增加,荧光性增强掺杂邻菲咯啉形成的混合LB膜,其荧光性比纯膜强。n(配合物B):n(邻菲咯啉)=1:10时有最好的荧光行为.
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Experimental electron diffraction patterns and high resolution images were used to determine the space group and unit cell dimensions of 2,3,6,7,10,11-hexakispentyloxytriphenylene. Subsequently the molecular conformation was calculated by energy minimized package in Cerius2. Using this method, we got the HPT crystal structure: space group: P6/mmm; lattice type: hexogonal; the lattice parameters are a = b = 20.3 angstrom, c = 3.52 angstrom, = = 90 degrees, = 120 degrees. The core of HPT is not perpendicular to the column. The angle between a axis and HPT core plane is 9 degrees which cannot be seen in b-c projection. The simulated ED patterns and HREM images are good agreement with the experimental ED patterns and HREM images.
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Two types of macromolecular free radicals -CH2CONHCHCH2- (a) and -CH2C=O (b) trapped in irradiated Polyamide-1010 (PA1010) and PA1010 filled with neodymium oxide (Nd2O3) were characterized by an ESR approach. It was found out that a was mainly trapped in the fold surface of the lamellae and b in the amorphous phase. This result suggested that trapped radicals mainly existed in the noncrystalline phases. The effect of the fold surface area of the lamellae on the behavior of the trapped radicals are discussed in this article. Whether for the specimens with similar crystallinities but different crystallite sizes or for those with the same concentration of neodymium oxide but different crystallinities, radical a exists dominantly in a specimen with a larger fold surface area of the lamellae. Under a certain circumstance, radical a can transform into radical b for a specimen with a larger fold surface area of the lamellae. It means that the fold surface area of the lamellae plays an important role in the transformation of radical a to b. (C) 1998 John Wiley & Sons, Inc.
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A new heteropolycomplex, K6H3[ZnW11O40Al] . 9.5H(2)O was prepared and characterized by means of elemental analysis, IR, UV spectroscopy, Al-27 NMR, electrochemistry and X-ray crystallography. The crystal of K6H3[ZnW11O40Al] . 9.5H(2)O is cubic, space group Fm-3m, with lattice constants a=b=c=2. 144 8(2) nm, V = 9.866(2) nm(3), Mo radiation, R = 0.057 8 for 497 independent data with [I>2 delta(I)]. The anion is of alpha-type Keggin structure with C-s symmetry.
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Using the wide-angle X-ray diffraction method, the variation of crystallographic parameters of poly(aryl ether ether ketone ketone) (PEEKK) has been studied in different heat treatment temperatures. All the reflections and their intensities as well as their Miller indices are presented in detail according to an orthorhombic system. The investigation indicates that the unit cell parameters a, b, c and the unit cell volume V systematically decrease with increasing heat treatment temperature. This variation is interpreted by the change of conformation of polymer molecular chains during thermal treatment. The results calculated from the formula of degree of crystallinity (W-c,W-x) for PEEKK, which was derived based on X-ray scattering intensity theory and the graphic multipeak resolution method, are compatible with the density measurement (W-c,W-d) and calorimetry (W-c,W-h) values. (C) 1997 Elesevier Science Ltd.
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Two types of macromolecular free radicals similar to CH2CONH(C) over dotHCH(2) similar to (a) and similar to CH2(C) over dot = O (b) trapped in irradiated polyamide-1010 (PA1010) and PA1010 filled with neodymium oxide (Nd2O3) were characterized by an ESR approach. It is found that (a) is prevailingly trapped in the fold surface of the lamellae and (b) in the amorphous phase. This result suggests that trapped radicals mainly exist in the non-crystalline phases. The effect of the fold surface area of the lamellae on the behavior of the trapped radicals is discussed in this paper. Whether for the specimens with similar crystallinities, but different crystallite sizes, or for those with the same concentration of neodymium oxide, but different crystallinities, radical (a) exists dominantly in the specimen with a larger fold surface area of the lamellae. Under certain circumstances, radical (a) can transform into radical (b), obviously for a specimen with a larger fold surface area of the lamellae. It means that the fold surface area of the lamellae plays an important role in the transformation of radical (a) to (b). (C) 1997 Elsevier Science Ltd.
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采用聚丙烯酰胺凝胶垂直板电泳方法分析有亲缘关系的37个品种(包括15个品种的亲本来源)萌发6天的大豆子叶POD同工酶谱。结果表明,不同品种POD同工酶谱共显示5~10条酶带,分A、B、C三区。以B区酶带色度深浅及数目变化为分类标准,可分为四种酶型:PB_1型、PB_2型、PB_3型和PB_4型。根据此酶型分析了每一个组合的品种与其两亲本。其中6个品种呈现偏父本酶型,6个品种呈现新酶型,2个品种的酶型与父母相同,1个品种呈现偏母本酶型。同时测定了13个组合的36个品种的POD比活力,结果指出:后代品种POD比活力都低于或介于父母本之间,后代比双亲POD比活力有逐渐降低的趋势。
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本文以1-丁烯在水蒸汽存在下选择性氧化制甲乙酮为典型反应,利用 XRD,ESR,IR,XPS,TEM 和 SEM 研究了 Sn-Mo 氧化物的结构与活性的关系.制备了8个样品,A,B,C,D,E,F,G 和 H 的 Mo/(Mo+Sn)分别为0,0.1,0.2,0.4,0.6,0.8,0.9,1.0.根据结构特征,可将 Sn-Mo 氧化物分为三组:第Ⅰ组 Mo/(Mo+Sn)≤0.2;第Ⅱ组0.2
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本文用X射线衍射、碘量法,扫描电镜等手段系统地研究了RBa_2Cu_3O_7-δ[R=La、Nd、Sm、Gd、Dy、Er、Yb、(DyYb)]化合物的结构和某些性质(如氧含量、Cu~(3+)/Cu~(2+)等)随稀土离子半径的变化规律。发现随着稀土离子半径的减少,晶胞参数(a、b、c、v)几乎线性降低,Cu~(3+)/Cu~(2+)(%)、氧含量(7-δ)、正交畸变(a-b)几乎线性增加,XRD图谱中001峰加强,SEM像中晶形更加完整。
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对YBa_2Cu_3O_(7-y):Ag_x超导体的性质进行了研究。该体系有较低的正常态电阻。XRD分析表明,在x<0.2时,该体系为正交结构。随Ag含量的增加,123相的α轴与b轴无明显改变,而c轴增加。X=1.5时,c轴增加了0.33%,表明有部分Ag进入123相晶胞。SEM研究表明,YBa_2Cu_3O_(7_y):Ag_x超导体晶粒细化均匀,晶粒间形成网状结构,改善了弱连接,使其临界电流密度J_c从50A/cm~2提高到572A/cm~2。
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研究了未掺杂及掺杂铬和铒ZrO_2-Y_2O_3(88:12mol%)晶体室温下的吸收和发光光谱。未掺杂晶体吸收和发光带是由色心引起,~(60)Co γ射线辐照前后其电子顺磁共振证实单电荷(Y_(Zr),Vo)′络合在点阵中存在。掺杂晶体的吸收、激发和发光光谱带相应于各自Cr~(3+)和Er~(3+)离子能级跃迁。使用3d~3电子久期方程计算3Cr~(3+)在立方场下库仑相互作用参数B、C和内晶格场参数D_q。
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本文根据总萃取比恒定的三出口萃取工艺(A/B/C)中各组份的动态物料平衡,采用 FORTRAN 语言编写了串级萃取动态模拟计算程序,并进行了正常启动和回流启动两种动态过程的实例计算。结果表明,各组份在级体内总量及各出口产品纯度等均随串级排数增多而逐渐趋近于静态模拟计算结果。采用回流方法启动时,可显著缩短达到稳态所需的时间,大大减少启动过程中的非合格产品。本文还根据多个萃取体系的动态模拟结果,分别对萃取段或洗涤段开设第三出口的工艺介绍了回流启动方法。
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In order to investigate the possible effects of the ecological environment on photosynthetic activity and the major light harvesting complex, the oxygen evolution rates and composition of phycobilisome from marine red alga Porphyra yezoensis Ueda and freshwater red alga Compsopogon coeruleus (Balbis) Montagne, which could grow and reproduce under salinity up to 35 ppt, were studied. The results showed that the oxygen evolution rate of P. yezoensis in seawater was significantly higher than that of C. coeruleus in freshwater, and P. yezoensis tolerated inorganic ions at a relatively higher concentration than C. coeruleus. Moreover, the phycoerythrin (PE) of P yezoensis was R-phycoerythrin containing alpha, beta, and gamma subunits comprised phycoerythrobilin and phycourobilin. In contrast, the PE from C. coeruleus consisted of alpha, beta, and gamma subunits comprised only phycoerythrobilin but not phycourobilin, suggesting that the PE from C. coeruleus was of a new type.