954 resultados para Er : YAB


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Reaction of lanthanide trichlorides with two equivalents of sodium t-butylcyclopentadienide in THF gave rise to the bis(t-butylcyclopentadienyl)lanthanide chloride complexes [(Bu(t)Cp)2LnCl]2 (Ln = Pr, Gd, Er), which were characterized by elemental analysis, IR and H-1 NMR spectroscopy. In addition, the crystal structures of [(ButCp)2PrCl]2 (1) and [(ButCp)2GdCl]2 (2) were determined by single crystal X-ray diffraction at room temperature. The coordination number for Pr3+ and Gd3+ is 8 and the bond lengths Pr-Cl and Gd-Cl are 2.864(2) and 2.771(3) angstrom, respectively. The structural studies showed the complexes to have C2h symmetry.

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The reaction of ErCl3 with one equivalent of C5H9C5H4Na generates the complex {[(C5H9C5H4)Er(THF)]2(mu2-Cl)3(mu3-Cl)2Na(THF)2}.THF, which crystallizes from hexane/THF. The X-ray crystal structure determination shows that each erbium is surrounded by one C5H9C5H4 ligand, two mu3-Cl, two mu2-Cl and one THF in a distorted octahedral arrangement.

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一般的光纤通信,由三部分组成,它包括两个终端站(发送和接受)和一个中继站,它们之间由光纤组成的光缆作为线路互相连接起来。其中中继站的中继机是为了补偿光信号在通过光纤时所发生的损失而架设的。最近,各国都积极研究不用中继机或为延长中

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合成了三茚基稀土配合物(η~5-C_9H_7)_3Ln·OC_4H_8(Ln=Nd、Gd、Er),经元素分析、红外光谱、水解产物核磁共振谱及质谱表征,并测得了(η~5-C_9H_7)_3Nd·OC_4H_8(1)及(η~5-C_9H_7)_3Gd·OC_4H_8(2)的晶体结构。(1)、(2)均属六方晶系,P6_3空间群,Z=2。(1)的晶体学参数为a=b=1.1843(3)nm,c=1.0304(4)nm,V=1.25165(87)nm~3,D_c=1.49g·cm~(-3),最后一致性因子R=0.049;(2)的晶体学参数a=b=1.1805(2)nm,c=1.0236(2)nm,V=1.23536(56)nm~3,D_c=1.54 g·cm~(-3),R=0.023。平均Nd-C=0.2812nm,Gd-C=0.2795nm;Nd-O=0.2557(21)nm,Gd—O=0.2459(13)nm。配合物中四氢呋喃的四个碳原子处于完全无序状态。

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The tetranuclear nearly-linear complex (eta-8-C8H8)Er(mu-eta-8-C8H8)K(mu-eta-8-C8H8)Er(mu-eta-8-C8H8)K(THF)4 (THF = tetrahydrofuran) is first synthesised by the reaction of benzylcyclopentadienyl erbium dichloride (PhCH2C5H4)ErCl2.3THF with cyclooctatetraenyl potassium K2C8H8 in 1:1 molar ratio in THF; a single crystal X-ray study has shown that the complex has the tetralayer-sandwich structure and that the adjacent Er3+ and K+ ions are bridged by eta-8-cyclooctatetraenyl group.

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The complexes named in the title (eta-5-C9H7)3Ln.OC4H8 (Ln = Nd, Gd, Er) were synthesized by the reaction of anhydrous lanthanide trichlorides with indenyl potassium and cyclooctadienyl potassium (1:2:1 molar ratio) in THF. The complexes were characterized by elemental analysis, infrared and H-1-NMR spectroscopy, and mass spectrometry. In addition, the crystal structures of (eta-5-C9H7)3Nd.OC4H8 (1) and (eta-5-C9H7)3Gd.OC4H8 (2) were determined by an X-ray diffraction study. Complexes 1 and 2 belong to hexagonal space group P6(3) with unit cell parameters a = b = 11.843(3), c = 10.304(4) angstrom, V = 1251.7(9) angstrom-3, D(c) = 1.49 g.cm-3, Z = 2 for 1, and a = b = 11.805(2), c = 10.236(2) angstrom, V = 1235.4(6) angstrom-3 D(c) = 1.54 g.cm-3, Z = 2 for 2. The structures were solved by Patterson and Fourier techniques and refined by least-squares to final discrepancy indices of R = 0.049, R(w) = 0.053 using 925 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 1, and R = 0.023, R(w) = 0.025 using 1327 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 2. Coordination numbers for Nd3+ and Gd3+ are 10; the average bond lengths Nd-O and Gd-O are 2.557(21) and 2.459(13) angstrom, respectively. The structural studies showed the complexes to have 3-fold symmetry, but the THF molecule has no such symmetry; consequently the arrangement of carbon atoms in the THF molecule are disordered.

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YAG:Er~(3+)晶体中Er~(3+)在红外新波段所谓“大气窗口”的激光发射,由于具有优异性能,研究此材料者日益增多。但红外波段荧光光谱除有局部的报导外,尚无系统报导,近年来我们对0.80—3.00μm波段的Er~(3+)离子的荧光光谱,进行了较详细的研究,并获得了较为满意的结果。这些结果,对从事YAG:Er~(3+)材料和器件的工作者,无疑是较为有益的参考

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本文讨论了激光晶体YAG:ErEr~(3+)浓度效应所引起的晶体结构畸变,Er~(3+)离子高激发态(~4S_(3/2),~4F_(9/2)和~2H_(11/2)能级)的发光与浓度猝灭,~4I_(11/2)→I_(13/2)自饱和跃迁和激光波长红移的变化规律。

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H(DEHP)是HEH(EHP)和HDEHP的同系物,它们的结构分别为:HDEHP,(GO)_2PO(OH);HEH(EHP),(GO)(G)PO(OH);H(DEHP),(G)_2PO(OH)。其中G为2-乙基已基。 希土元素萃取分离工艺化学表明,溶剂萃取希土元素对酸度的依赖关系及相邻希土元素间的分离因素值是选择萃取剂时应优先考虑的因素。HDEHP萃取剂对中、重希士元素反萃酸度高,HEH(EHP)是一个优良萃取剂,但对Er,Tm,Yb,Lu的反萃仍需5mol/l的酸。由于H(DEHP)分子中不含酯氧原子,使得它的pK_a值比HDEHP和HEH(EHP)的高。从而,用H(DEHP)萃取希土元素时需要的水相酸度更低,反萃更容易。而且H(DEHP)

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环氧树脂(ER)与聚环氧乙烷(PEO)的共混物经水/乙醇萃取后的剩余物为交联ER-PEO非晶共聚物。萃取分析表明,ER/PEO中约有50wt·%的PEO与ER形成ER-PEO交联共聚物。ER/PEO与NaSCN络合后,由于Na~+的配位络合作用,使结晶能力进一步降低。

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研究了水热法合成晶体,浓度配比、生长温度对晶体生长习性的影响.合成了一系列化学计量比的Y_(1-x-0.3)Er_(0.3)Tm_xP_5O_(14)(x=0.01~0.1)晶体,观察和分析了晶体的缺陷及成因,测定和讨论了晶体结构.

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本文讨论和分析了激光晶体YAG中Er~(3+)离子的激光上能级的~4S_(3/2)、~4I_(11/2)和~4I_(13/2)辐射跃迁的有关因素。

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Hincks, R. (2007). Beza? beleg a zo kargus koulz 'vel beza? relijiuz: Ur sell ouzh eus an Iliz, ar gloer, ar veleien hag ar relijiuzed er gwerzio? hag er sonio? brezhonek, gant evezhiadenno? war un nebeud liammo? etre an taolennadur-se hag an hengoun kembreat. Roazhon: hor Yezh.

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In S. cerevisiae lacking SHR3, amino acid permeases specifically accumulate in membranes of the endoplasmic reticulum (ER) and fail to be transported to the plasma membrane. We examined the requirements of transport of the permeases from the ER to the Golgi in vitro. Addition of soluble COPII components (Sec23/24p, Sec13/31p, and Sar1p) to yeast membrane preparations generated vesicles containing the general amino acid permease. Gap1p, and the histidine permease, Hip1p. Shr3p was required for the packaging of Gap1p and Hip1p but was not itself incorporated into transport vesicles. In contrast, the packaging of the plasma membrane ATPase, Pma1p, and the soluble yeast pheromone precursor, glycosylated pro alpha factor, was independent of Shr3p. In addition, we show that integral membrane and soluble cargo colocalize in transport vesicles, indicating that different types of cargo are not segregated at an early step in secretion. Our data suggest that specific ancillary proteins in the ER membrane recruit subsets of integral membrane protein cargo into COPII transport vesicles.