978 resultados para NI(ACAC)(2)-METHYLALUMINOXANE CATALYST


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A ternary supramolecular complex of [Ni(bipy)(2)(H2O)](4)(C8AS)center dot 17.6(H2O) (bipy=4,4'-dimethyl-2,2'-bipyridine and C8AS = p-sulfonatocalix[8]arene) has been synthesized by a hydrothermal method and characterized by FT-IR spectroscopy, TG-DTA analysis and single crystal X-ray diffraction. In the structure. the water-soluble p-sulfonatocalix[8]arene molecule adopts a double partial cone conformation and is coordinated by four nickel atoms each of which is bonded by two 4,4'-dimethyl-2,2'-bipyridine molecules and one water molecule at the same time. The tetranuclear Subunits are stacked into an extended 3D structure with 1D water-filled channels via hydrogen bonds and C-H center dot center dot center dot pi interactions.

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采用低热固相反应法合成掺杂Cu的Ni(OH)2,将其在300℃下热处理得到相应的NiO.电化学测试表明∶掺杂量为n(Ni)∶n(Cu)=100∶0.25时,NiO电极的比容量最高,为99-120 F/g,具有良好的充放电性能,而不掺杂的只有83-111 F/g,因此掺杂Cu有利于提高NiO的电化学性能.

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Polyethylene-polystyrene blends were synthesized by in situ ethylene polymerization with polystyrene porous beads supported metallocene; the influence of fragmenting support beads on the morphology and the mechanical performance of the blends was investigated.

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A novel biodegradable amphiphilic block copolymer PLGG-PEG-PLGG bearing pendant glucose residues is successfully prepared by the coupling reaction of 3-(2-aminoethylthio) propyl-R-D-glucopyranoside with the pendant carboxyl groups of PLGG-PEG-PLGG in the presence of N,N'-carbonyldiimidazole. The polymer PLGG-PEG-PLGG, i.e., poly {(lactic acid)-co-[(glycolic acid)-alt-(L-glutamic acid)]}-block-poly(ethylene glycol)-block-poly{( lactic acid)-co-[( glycolic acid)-alt-(L-glutamic acid)]}, is prepared by ring-opening copolymerization of L-lactide (LLA) with (3s)-benzoxylcarbonylethylmorpholine-2,5-dione (BEMD) in the presence of dihydroxyl PEG with molecular weight of 2000 as macroinitiator and Sn(Oct)(2) as catalyst, and then by catalytic hydrogenation. The glucose-grafted copolymer shows a lower degree of cytotoxicity to ECV-304 cells and improved specific recognition and binding with Concanavalin A (Con A). Therefore, this kind of glucose-grafted copolymer may find biomedical applications.

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Nickel appears the most promising for the replacement of palladium among the inexpensive transition metals for that it is active for Heck reaction and about 500 times cheaper than palladium. In this article, we describe our recent results in the area of nickel-catalyzed Heck vinylations. Main focus is on the influence of ligand concentration in different organic solvents and the effects of the addition of water. The conversion is high in NMP and increases with increasing of PPh3/Ni ratio; in ethanol and toluene the conversion presents a maximum value on Ni(PPh3)(2). The effect of the addition of water is sensitive to the concentration of PPh3 and the nature of solvent, it was well explained with the formation and transfer of the active species in the different solvent systems.

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The oxamido-bridged heterobinuclear copper(II)-nickel(II) complex, [Cu(oxbe)Ni(phen)(2)]ClO4.3H(2)O (1) and homotrinuclear nickel(11) complex {[Ni(oxbe)](2)Ni(H2O)(2)}.2.5DMF (2) have been synthesized and characterized by means of elemental analysis, IR, EPR. and electronic spectra and magnetic susceptibility, where H(3)oxbe is dissymmetrical ligand N-benzoato-N'-(2-aminoethyl)ox-amido, phen = 1.10-phenanthroline, DMF = dimethylformamide. Complex I has an extended oxamido-bridged structure consisting of planar copper(II) and octahedral nickel(II) ions. The chi(M) and mu(eff) versus T plots of 1 is typical of an antiferromagnetically coupled Cu(II)-Ni(II,) pair with a spin-doublet ground state, and magnetic analysis leads to J = -57.1 cm(-1). The molecular structure of 2 is centrosymmetrical, with one octahedral nickel atom lying at an inversion center and two terminal Ni(II) atoms in approximately square planar environment. Through the hydrogen bonds and pi- pi stacking interactions, a 2D supramolecular structure is formed.

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Ethylene homopolymerizations and copolymerizations were catalyzed by zirconocene catalysts entrapped inside functionalized. montmorillonites that had been rendered organophilic via the ion exchange of the interlamellar cations of layered montmorillonite with hydrochlorides Of L-amino acids (AAH(+)Cl(-)) or their methyl esters (MeAAH(+)Cl(-)), with or without the further addition of hexadecyltrimethylammonium bromide (C16H33N+Me3Br-; R4N+Br-). In contrast to the homogeneous CP2ZrCl2/methylaluminoxane catalyst for ethylene homopolymerizations and copolymerizations with 1-octene, the intercalated Cp2ZrCl2 activated by methylaluminoxane for ethylene homopolymerizations and copolymerizations with 1-octene proved to be more effective in the synthesis of polyethylenes with controlled molecular weights, chemical compositions and structures, and properties, including the bulk density. The effects of the properties of the organic guests on the preparation and catalytic performance of the intercalated zirconocene catalysts were studied.

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原子力显微镜 ( AFM)自 1 986年发明以来得到了广泛的应用和发展 [1,2 ] ,成为众多研究领域中的强有力工具 ,并为其它的研究技术提供了良好的互补手段 .DNA是 AFM首次研究的生物样品之一 ,它使人类首次观察到 DNA分子的原始形貌 ,并实现了接近生理条件下的操作 ,使得随时监测生物大分子的生化反应过程成为现实 [3,4 ] .在 DNA的 AFM研究中 ,样品的制备是其关键 .以阳离子 (如 Mg2 + ,Ba2 + ,Mn2 +和 Ca2 +等 [5] )固定法较为常见 ,其操作简单 ,固定效果好 ,基底效应小 ,但也有一定的局限性 ,如存在限制性内切酶时 ,这些简单离子会催化酶对 DNA分子的切割作用 ,从而不利于完整 DNA分子链上酶的特异与非特异吸附定位的研究 .本文采用 AFM技术 ,研究了 Ni( phen) 2 + 3 在云母片上对线形 DNA分子的固定与展开作用 ,并对所采集的图像进行了初步分析和处理 .1 实验部分1 .1 样品与制备 Ni( phen) 2 + 3 由 Ni2 SO4 (分析纯 )和 1 ,1 0 -邻菲绕啉 (分析纯 )制备 .PBR32 2 /pst ...

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本文主要报道一种可用于含过渡金属层状VOP化合物的直接合成方法和用该方法合成的一个新层状乙酰丙酮铜配合物嵌入的磷酸钒(Cu(acac)<,2>-LVPO),并对其进行了结构表征.

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目前使用的碱性二次电池中,镍系列电池占有很重要的地位,其中镍电极是其核心.镍电极的研究集中于掺杂离子对电极过程的作用机理、具有优良的电化学性能的稳定的α-Ni(OH)2和纳米Ni(OH)2的制备等三个热点上.由于NiOOH/Ni(OH)2电化学储能所涉及的活性物质在碱性介质中具有不溶解性及长寿命的优点,所以氢氧化镍特别适宜作为碱性蓄电池的正极活性物质.

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Graft copolymers of polyethylene (PE) with polyisoprene (PI) were synthesized through polymerization of ethylene in toluene solution of PI (cis-1,4-: 95%; 3,4-: 5%) using a homogeneous V(acac)3/Et3Al2Cl3 catalyst. Copolymers are formed when the growing po

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微孔配位聚合物是近年来被广泛研究的领域之一,这类材料在储气材料等领域的应用前景逐步被开发出来。作为良好的储气材料,配位聚合物必须具有规则的孔道结构和良好的稳定性。本论文以合成多维孔道新化合物为目标,成功合成并解析出13个微孔配位聚合物。对化合物的元素分析、红外和TGA等进行了表征,同时对部分化合物的紫外和荧光性质进行了测定。 首先,对微孔配位聚合物的最新研究动态进行了简要介绍,并对一些代表性化合物的结构类型、性能以及应用等进行了归纳总结。然后介绍了合成配位聚合物晶体的实验原理,化合物的表征方法。 本论文在水热条件下,成功合成了13个新化合物分别为:(C19H15N4)2(NO3)2∙3H2O (3-3),(C19H15N4)2[CdCl4] (3-4),2Ag(tta)∙AgNO3 (3-5),Cu8(tta)15(H2O)Cl (3-6),[Zn(5-CH3-tta)2(isoH)2] (BDC) (3-7),Pb[(PO3)2C(OH) CH3]•H2O (4-1),Ni(C5H4NCOO)2∙4H2O (5-2),Co(C5H4NCOO)2(H2O)2∙2H2O (5-3),[CdCl2(C13H12N2O)2] (5-4),{C6H4(COOH)S}2 (5-5),(Deta)(ClO4)NO3 (5-6),(NH4)2[-Mo8O26] (6-1) 和 (NH4)2[Mo4O13] (6-2)。其中化合物3-5,3-6和3-7是由四氮唑和金属构筑的纳米孔道三维化合物;化合物3-3,3-4,5-2,5-3,5-4,5-5和5-6均具有超分子网络结构;4-1是有机膦酸为配体的二维层状化合物,是首例(5,5)连接的(47•63) (48•62)拓扑网络。化合物6-1是一维无限链骨架的钼酸盐,6-2是二维层状的钼酸盐,显示了不寻常的(32•4)(32•53•8)(3•42•54•6•82)(34•43•54•64) 拓扑网络。最后对论文进行概括总结,并展望了下一阶段的工作安排。

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An assessment of metal contamination in surface sediments of the Jiaozhou Bay, Qingdao, one of the rapidly developing coastal economic zones in China, is provided. Sediments were collected from 10 stations and a total of 15 heavy metals were analyzed. Concentrations of metals show significant variability and range from 210 to 620 ppm for Ti, 2.7 to 23 ppm for Ni, 4.2 to 28 ppm for Cu, 5.2 to 18 ppm for Pb, 12 to 58 ppm for Zn, 0.03 to 0.11 ppm for Cd, 5 to 51 ppm for Cr, 1.5 to 9.9 ppm for Co, 5.3 to 19 ppm for As, 12 to 32 ppm for Se, and 19 to 97 ppm for Sr. Based on concentration relationships and enrichment factor (EF) analyses, the results indicate that sediment grain size and organic matter played important roles in controlling the distribution of the heavy metals in surface sediments of the Jiaozhou Bay. The study shows that the sediment of the Jiaozhou Bay has been contaminated by heavy metals to various degrees, with prominent arsenic contributing the most to the contamination. The analysis suggests that the major sources of metal contamination in the Jiaozhou Bay are land-based anthropogenic ones, such as discharge of industrial waste water and municipal sewage and run-off. Notably, the elevated heavy metal concentrations of the Jiaozhou Bay sediments could have a significant impact on the bay's ecosystem. With the rapid economic development and urbanization around the Jiaozhou Bay, coastal management and pollution control should focus on these contaminant sources, as well as provide ongoing monitoring studies of heavy metal contamination within the bay.

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金川矿床是超大型岩浆 Ni-Cu-PGE 硫化物矿床,它赋存有世界第三的镍储量(5.45×106 t,Ni 的平均品位为 1.2%)。该矿床位于华北板块西侧阿拉善地块西南边缘龙首山隆起中。本论文以金川矿区的 II 号岩体为研究对象,在系统整理前人工作的基础上,通过深入细致的野外地质考察和系统采样,选取有代表性的样品,进行详细的显微镜鉴定,并运用元素地球化学等手段,对 II 号岩体的源区特征、岩浆演化过程及其赋存的⑴、⑵号矿体的成矿机制等主要矿床学问题进行了系统成因研究,并尝试提出了二次硫化物熔离成矿模式。本论文主要取得以下几点结论性成果: 1)岩浆起源:起源于上地幔尖晶石-石榴石二辉橄榄岩过渡地带的下部。通过上地幔源岩的柱状部分熔融模式(≥25%)或三角部分熔融模式(10~15%),形成富PGE的S不饱和原始岩浆。 2)地壳同化混染:地壳物质的同化混染主要是由早期下地壳物质的同化混染和晚期上地壳物质的同化混染组成的多阶段同化混染,并且其成分为富钙质围岩。 3)结晶分异演化:金川II号岩体作为橄榄石堆积相,其橄榄石的结晶主要发生在上地壳深部岩浆房,而橄榄石与熔浆的反应及辉石和斜长石的结晶则主要发生在浅部岩浆房,既现今岩体所在位置。 4)S 的饱和机制:岩浆通道内下地壳物质的同化混染,导致岩浆硫饱和,并于岩浆通道中发生了第一次硫化物熔离;上地壳深部岩浆房中地壳物质的同化混染和橄榄石的分离结晶,促使硫饱和的母岩浆发生了第二次硫化物熔离。 5)深部岩浆房的演化:上地壳深部岩浆房中橄榄石分离结晶与硫化物熔离之后,在重力分异作用下,形成了自上而下的硅酸盐岩浆、橄榄石“晶粥”、含硫化物熔体的橄榄石“晶粥”以及矿浆的四层分层格局。同时,底部部分硫化物熔体发生了Pt合金(Pt-Fe)的脱离。 6)侵入期次:上地壳深部岩浆房中,母岩浆分异演化早期,其顶部含有尚未完全成长橄榄石颗粒的“晶粥”在构造应力挤压下首先上侵、成岩形成金川II号岩体顶部、呈“上悬体”的中细粒含辉橄榄岩;分层格局形成之后,橄榄石“晶 VI 粥”、含硫化物熔体的橄榄石“晶粥”以及矿浆依次上侵成岩、成矿,分别形成金川 II 号岩体上部的二辉橄榄岩相、⑴、⑵号矿体的主体以及⑵号矿体底部的块状矿石。

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土壤是自然环境的重要组成部分,是人类赖以生存与发展的宝贵资源。但是近年来我国土壤重金属污染日益严重,重金属污染物与其它类型的污染物相比具有隐蔽性、长期性与不可逆性等一系列特殊性,成为土壤中永久的污染物,最终通过食物链的传递进入人体,对人类的健康造成潜在的危害。因此,研究土壤重金属污染与控制具有很重要的意义。本论文首次将唐南膜平衡法(DonnanMembraneTechnique)和EcosAT(EquilibriumCalculationOfSpeciationAndTransport)模型引入我国土壤重金属活动性研究,并将两种方法获得的结果进行比较,互相验证,取得了较好的结果。还将两种方法结合探讨了贵州铝厂生产的赤泥对土壤中的游离重金属离子浓度的影响。土壤样品采于贵州都匀福锌矿地区,一个位于锅锌矿选厂尾矿坝下农田中的水稻土,以下简称坝下土,为重污染土;另一个位于锅锌矿上游桥边农田中的水稻土,以下简称桥边土,为轻污染土,本研究取得的主要结论与认识包括:1.作者对唐南膜平衡法进行了部分改进,用国内生产的JAM一I型均相离子交换膜替换Brwin等所用的BDH膜,既降低了实验的平衡时间,又经济实惠。另外还用KNO3溶液代替KNO3和Ca(NO3)2混合溶液作为实验的介质溶液,就可以避免由于国内土壤中Ca2+含量差异较大可能造成的误差。其它实验条件为:蠕动泵的流速为2.0ml/min,平衡时间为48小时。2.用柠檬酸体系(液一液体系)和土壤一水体系(固一液体系)检验了唐南膜平衡法,它可以在不扰动体系平衡的基础上同时测定同一体系中的多个游离金属离子浓度,而且各金属离子之间互不干扰。3.桥边土中的游离重金属离子浓度与其中2mol/LHNO3提取的重金属总含量成很好的直线关系,其中Cu和Zn游离离子浓度与其中的总金属含量呈现较好的正比关系,随着重金属总含量的降低,即土液比的降低,游离重金属离子浓度随之降低;而其中的Ni和Cd却相反,随着重金属总含量的降低,游离重金属离子浓度反而增加。添加赤泥后随着土液比的降低各重金属的游离离羲?子浓度的变化趋势与添加赤泥前一样。桥边土中的重金属游离离子浓度在添加联合法赤泥后有所增加,而拜尔法赤泥的加入降低了其中的游离重金属离子浓度,加入的比例越大,变化的量越多,而且其中Ni和cd的变化幅度比Cu和Zn的要大。4.坝下土中Cu、Zn、Ni和Cd元素的游离离子浓度与它们在土壤中Zmol/LHNo3提取的重金属总含量呈很夯的正比关系,随着重金属总含量的降低,游离重金属离子浓度随之降低。添加赤泥后其中Cu和Zn元素的变化趋势与添加赤泥前一样,Ni和Cd元素出现了异常,Ni在赤泥添加比例为0.50%时变化趋势一样,但添加比例为2.00%时其离子浓度先增加,但在土液比为1:100时反而有较大幅度的降低。而其中Cd离子浓度先增加,在土液比为1:100时反而有较大幅度的降低。坝下土中Cu和Zn的游离离子浓度在添加赤泥以后改变很小,赤泥添加比例为2.00%的土壤中的游离离子浓度相对较低一点,而添加比例为0.50%的与未加赤泥的土壤基本上一样;其中Ni和Cd的变化相对来说较大,赤泥添加比例为2.00%的土壤中的游离离子浓度降低得比较明显,拜尔法赤泥添加比例为0.50%的土壤也得到了较大的改善,而联合法赤泥添加比例为0.50%的却比未加赤泥的土壤中的还要高一点。5.利用ECOSAT模型模拟了本论文所涉及的实验中的游离重金属离子浓度,测量值与模拟值取得了较好的一致,除了Zn的误差较大以外,其它三个元素符合的很好,从而表明EC0sAT在土壤一水系统中的模拟取得了较好的结果。6.模拟了不同土液比土壤中各重金属元素在有机质、铁氧化物、粘土和唐南凝胶体这四种吸附相中的分配。发现在所研究的土壤样品中所有元素在粘土相中所占的比例很小,可以忽略不计,Cu主要分布在有机质相中,占80%左右,随着土液比的降低,其在有机质和唐南凝胶体相中的分配比例慢慢变小,而在铁氧化物中的比例越来越大;Zn主要分布在有机质和铁氧化物相中,各占40%左右;随着土液比的降低,Zn在有机质相中的比例增大,铁氧化物比例几乎不变,而唐南凝胶体所占比例逐渐减小;Ni基本上只分布在有机质和铁”氧化物相中,Cd则几乎只存在于有机质相中,它们的分布比例几乎不随土液比的改变而变化。7.无论在桥边土和坝下土中添加何种赤泥,添加的比例是多少,在添加赤泥前后土壤中重金属元素在各吸附相中的分配比变化很小,主要是有机质相所占比例稍微变小,而铁氧化物相相应的有一点增加。而对于不同的土液比,其变化趋势相同,只是变化幅度相对来说较大。