Molten and solidification properties of copper nanoparticles

The melting and solidifying processes are carried out using molecular dynamics simulations. The influencing mechanism of the simulation size and the crystal configuration after solidification on the molten and the solidification properties is explored. The results demonstrate that the crystal structure of solidified copper nanoparticle is sensitive to the size of the copper nanocubes. Polycrystalline appears in the solidified copper nanoparticle for the relatively larger copper cubes; correspondingly, the grain boundaries give rise to the increase of the average atomic energy. Whereas for the relatively small copper cubes, the solidified copper nanoparticles mainly present monocrystalline structure. Moreover, the relationship between the internal pressure of the liquid copper droplets and the droplet diameter is studied to clarify the surface tension property at nanoscale. It is found that the internal pressure of the liquid copper droplets is logarithmically linearly dependent on the diameter of the copper droplets, implying that the surface tension of the liquid copper is not sensitive to the diameter of the liquid copper droplets. The present findings will be helpful to the preparation of the copper nanoparticle‐based thin ribbon. Copyright © 2016 John Wiley & Sons, Ltd.     

应用波长色散X荧光仪和多晶X射线衍射仪联用技术 鉴定进口铜矿和含铜物料

本文首次研究进口可利用含铜物料与进口铜矿属性的不同特性并建立鉴定方法,采用X荧光光谱法和X射线衍射光谱法联用技术建立铜矿和含铜物料属性的鉴别方法。通过X荧光光谱法对铜矿和含铜物料中元素进行定性半定量分析,再用X射线衍射光谱法对铜矿和含铜物料的特征谱峰进行扫描,与X衍射仪中标准卡片比对分析,能够确定铜矿和含铜物料的物相组成。结果显示：X荧光光谱法铜矿和含铜物料的共同特点铜的含量较高,达到冶炼铜对原料的要求,硅、铁、钠、钙和镁元素都能够检出。差异性在铅和锌元素在含铜物料中较高,在铜矿石中基本未检出;在X荧光光谱法检测出的金属元素,通过X衍射仪扫描后与标准图片比对,各元素以不同的形式存在于含铜物料中,且有规律可循。     

贫血患者头发与末稍血中铁,铜含量对比研究

对两组贫血患儿用ＸＲＦ法测定头发及末稍血微量元素铁，铜含量，并与正常值做对比研究，结果显示：发铁高于正常，与血清含量降低相反，与部分研究结论相同。发铜你于正常，与血清结论相同。末销血铁，铜含量均低于正常，与血清铁，铜结论相同。末销血能否作为代表机体铁，铜含量的检验体，值得深入研究证实。     

The differential pulse anodic stripping voltammetry of copper and lead and their determination in EDTA extracts of soils with the mercury film glassy carbon electrode

The differential pulse anodic stripping voltammetry of copper and lead at the mercury film glassy carbon electrode is discussed. The mercury film prevents the occurrence of a monolayer stripping peak for copper. The influence of antimony and bismuth on the anodic stripping voltammetric behaviour of copper and lead is discussed. An interaction between copper and antimony distorts the copper stripping peak and gives rise to an intermediate peak. The method described is suitable for determining copper and lead simultaneously in EDTA extracts of soils.     

A polarographic study of the redox and complex-forming reactions of penicillamine, N-acetylpenicillamine and copper (I) or (II)

Polarographic methods are used to study the redox and complexation reactions between copper(II) or (I) and penicillamine, N-acetylpenicillamine or the oxidation product, dithiobisvaline. The formation of a 1:1 copper(I) complex between penicillamine and copper(I) was proved, and the stability of the complex measured. Copper(II) oxidizes the sulphur compound to the disulphide and the copper(I) formed then forms a complex with the sulphur amino-acid. The greater stability of the non-acetylated copper(I) complex suggests that RSCu(I) contains a chelate ring with participation of the free amino group. The disulphide can only form a complex with copper(II) and the stability of this complex is low. The results suggest that the copper(I) chelate is the form in which copper is eliminated during treatment with penicillamine.     

土壤铜污染的微生物及酶学指标研究

通过室内培养试验,研究了土壤铜污染对土壤微生物基础呼吸及土壤脲酶、脱氢酶、酸性磷酸酶的影响。结果表明,土壤微生物基础呼吸在低水平铜（≤100mg／kg）添加下呈现出先上升后下降的趋势,而随着土壤铜添加水平的进一步提高（〉100mg／kg）,微生物基础呼吸作用迅速增强;土壤脲酶则随着铜含量的增加呈现出不断下降趋势,土壤磷酸酶活性则在低水平下上升而随着添加水平的进一步提高迅速降低。可见,这两种酶对土壤铜毒害反应灵敏,可作为土壤铜污染评价的指标;而土壤脱氢酶则对铜含量的变化没有表现出明显的统计规律性,不适宜作为土壤铜污染评价的酶学指标。     

Preparation and properties of ligand-free methylcopper and of copper alkyls coordinated with 2,2′-bipyridyl and tricyclohexylphosphine

A series of copper alkyls (methyl, ethyl and n-propyl) with ligands (2,2′-bipyridyl and tricyclohexylphosphine) and copper methyl without ligands has been prepared by the reaction of copper(II) acetylacetonate with dialkylaluminum monoethoxides in the presence or absence of the ligand in diethyl ether under nitrogen at low temperature. The copper alkyls were characterized by elemental analysis, chemical reactions, and by IR and NMR spectra. The ligand-free methylcopper is thermally very unstable and decomposed explosively; the bipyridyl ligand showed little effect on the stability of the copper alkyl. In contrast, the tricyclohexylphosphine-coordinated complexes are thermally very stable. Various reactions of the tricyclohexylphosphine-coordinated copper alkyls toward carbon dioxide, alkyl halides and olefins have been studied.     

电位活化现象与金属电沉积初始过程的研究

进行了恒电流电位-时间曲线和循环伏安曲线的测定，显示了铁电极进行氰化物镀铜时，镀层沉积前铁表面的电位活化过程. 对铁电极上焦磷酸盐镀铜的初始过程研究表明，由于铜的析出电位较正，铜是在未活化的电极表面上沉积的，因此镀层的结合强度很差.采用氩离子溅射和X射线光电子能谱相结合的方法，检测焦磷酸盐镀铜层和铁基体界面区含氧量的变化，证明了氧化层的存在. 通过添加辅助络合剂和控制起始电流密度的方法，可以增强无氰电镀时阴极的极化. 当铜的析出电位负于铁基体的活化电位时，可显示出铁表面的电位活化过程，定量测量镀层的结合强度也与氰化物电镀相近.     

海藻酸酮膜表面的配位结构及催化MMA聚合的性能

将海藻酸钠(SA)与CuCl2.2H2反应得到一种配位聚合物海藻酸酮(Cu-An)。以ESR、电导率、IR和SPS方法对此配位聚合物进行表征,确定了组成与结构：同时研究了甲基丙烯酸甲酯(MMA)在该配位聚合物膜、HSO3^-和水体系催化引发作用下的聚合反应历程。结果表明,配位聚合物的中心离子Cu^2^+与两个海藻酸(An)链节单元上的两个羧羟基氧原子和两个离解氢原子的羧羟基氧原子以共价型配位,配位数为4.MMA在上述的催化引发体系中是按照自由基加聚反应历程进行聚合的,PMMA呈无规结构。Cu-An在催化引发体系中起着催化剂的配位催化作用。     

Kinetics of the dissolution of copper metal in aqueous solutions containing unsaturated organic ligands and copper(II)

The kinetics of the dissolution of copper metal in an aqueous solution containing copper(II) and an unsaturated organic ligand was followed by using an automated flow-injection analysis technique to determine the concentration of copper(I) in solution as a function of time. The results suggest that the rate of dissolution of the copper metal is dependent on electron transfer between the copper(II) and copper atoms on the surface of the copper metal, and on the stabilization of copper(I) by the unsaturated organic ligand in solution.     

Simultaneous adsorption of copper ions and humic acid onto an activated carbon

In this study, simultaneous adsorption of copper ions and humic acid (HA) from Aldrich onto an activated carbon is investigated. It is found that the HA adsorption in the absence of copper decreases as the pH is increased. It leads to a reduction of 34.7% in the specific surface area of carbon. There exists a critical concentration (CC) of HA for copper adsorption. At HA concentrations < CC, a decrease in copper adsorption is observed; however, the HA improves the adsorption at HA concentrations > CC. An increase in ionic strength can enhance the copper uptake; however, zinc and/or cobalt ions have an insignificant influence on copper adsorption. The adsorption is significantly increased by citric acid, whereas addition of EDTA slightly decreases the uptake. An intraparticle diffusion model is successfully used to describe the copper adsorption kinetics.     

铜源对溶胶-凝胶法制备La2CuO4晶体及光学性能的影响

以硝酸镧为镧源,柠檬酸为络合剂,水为溶剂,分别以硫酸铜,氯化铜和硝酸铜为铜源,采用溶胶-凝胶法制备了La2CuO4纳米晶。通过热重-示差扫描量热(TG-DSC),X射线衍射(XRD),红外光谱(IR),透射电子显微镜(TEM)和紫外-可见-近红外光谱(UV-Vis-NIR)等方法对La2CuO4粉体进行了测试和表征;研究了不同铜源对前驱体及La2CuO4粉体的热性能、相组成、官能团、显微结构及光学性能的影响。结果表明:以硫酸铜和氯化铜为铜源,600℃煅烧保温2 h,产物均含有杂质相,而以硝酸铜为铜源时,可获得单一的正交晶型的La2CuO4物相,晶粒尺寸80-100 nm。根据UV-Vis-NIR分析,La2CuO4的光学带隙依次为1.193 eV,1.258 eV,1.380 eV。     

Synthesis,Characterization, and Applications of Copper Nanoparticles

Copper nanoparticles with different structural properties and effective biological effects may be fabricated using new green protocols. The control over particle size and in turn size-dependent properties of copper nanoparticles is expected to provide additional applications. Various methods for the synthesis of copper nanoparticles have been reported including chemical methods, physical methods, biological methods, and green synthesis. Biological methods involve the use of plant extracts, bacteria, and fungi. Commendable work has been done regarding the synthesis and stability of copper nanoparticles. There is a need to summarize the behavior of copper nanoparticles in different media under various conditions. Here, a complete list of the literature on the synthesis of copper nanoparticles, their properties, stabilizing agents, factors affecting the morphology, and their applications is presented. The importance of copper nanoparticles compared to other metal nanoparticles are due to high conductivity. Methods for the synthesis of copper nanoparticles, including green protocols using plants and micro-organisms compared chemical methods, have also been reviewed.     

The polarographic determination of copper and zinc in plants and soils

A method is described whereby the extraction and polarisation of copper and zinc with maximum, sensitivity is possible. Interference from cobalt is prevented by extracting with dithizonc in the presence of dimethylglyoxime.The supporting electrolyte used is dccimolar potassium hydrogen phthalate which permits satisfactory waves for both copper and zinc (with greater sensitivity for copper, than is the case with the ammonia-ammonium chloride electrolyte).     

头发中微量铜和锌的 5-Br-PADAP 分光光度法测定

研究了测定铜和锌时多种掩蔽剂联合掩蔽头发中的干扰离子。测定铜时用六偏磷酸钠和焦磷酸钾联合掩蔽;测锌时用柠檬酸钠、六偏磷酸黄和铜试剂联合掩蔽。在表面活性剂OP存在下,5－Br-PADAP显色,不经分离,直接在水事测定斑秃患者头发中的铜和锌。铜络合物的最高吸收峰在558nm,锌络合物的最高吸收峰在560nm,在25mL溶液中,铜在0－37．5mg/L,锌在0－238mg/L范围内符合beer定律。斑秃患者头发中锌和铜低于正常人。     

Synthesis and size control of monodisperse copper nanoparticles by polyol method

We describe herein the synthesis of metallic copper nanoparticles in the presence of poly(vinylpyrrolidone), employed as a protecting agent, via a polyol method in ambient atmosphere. The obtained copper particles were confirmed by XRD to be crystalline copper with a face-centered cubic (fcc) structure. We observed monodisperse spherical copper nanoparticles with a diameter range 45+/-8 nm. The particle size and its distribution are controlled by varying the synthesis parameters such as the reducing agent concentration, reaction temperature, and precursor injection rate. The precursor injection rate plays an important role in controlling the size of the copper nanoparticles. On the basis of XPS and HRTEM results, we demonstrate that the surface of the copper is surrounded by amorphous CuO and that poly(vinylpyrrolidone) is chemisorbed on the copper surface.     

微量稀土对超导稳定化基体铜材的性能和组织的影响

研究了微量稀土元素对铜的机械性能、导电性和组织的影响，在铜中加入微量钇、钕、镝、铒和富铈混合稀土后，使铜的抗拉强度有所提高，并保持良好的塑性和导电性。     

The simultaneous determination of copper and nickel by solvent extraction and gas-liquid chromatography with bis (acetylpivalylmethane) ethylenediimine as reagent

The copper(II), nickel(II) and palladium(II) chelates of the bridged β-ketoamine, bis(acetylpivalylmethane) ethylenediimine, are described. The copper and nickel complexes are readily extracted by cyclohexane at pH 8.0 from aqueous solution. The gas chromatographic separation of the copper and palladium, the nickel and palladium, and the copper and nickel chelates is reported on a silicone gum rubber phase (E-350) supported on Universal B at 285°C. Optimal conditions for the complete separation of copper and nickel are reported; the solvent extraction—gas chromatographic procedures are applied to the determination of the individual metal ions (limit of detection, 1 ng) and to the simultaneous determination of copper and nickel in solution and in alloy samples. A rapid method for the determination of copper in domestic water samples is also described.     

Kinetics and mechanisms of the catalytic reactions of formaldehyde with copper oxides and a copper ion complex in aqueous alkali

The kinetics of the autocatalytic reactions of formaldehyde with copper(II) and copper(I) oxides and with the Cu²⁺ ion of the copper EDTA complex, as well as formaldehyde disproportionation in the presence of copper metal, have been investigated in aqueous solutions of sodium hydroxide. Two likely reaction mechanisms are presented. The difference between these mechanisms does not alter the observed kinetics of the processes, whose rate is determined by their first, slow step, namely, the oxidation of the methylene glycol anion adsorbed on the copper surface into formic acid. In the slow step of the first mechanism, a hydride ion is abstracted from the methylene glycol anion and is transferred to copper. In the slow step of the second mechanism, the methylene glycol anion undergoes anodic oxidation, releasing a hydrogen atom and an electron. In the rapid steps of the first mechanism, the hydride ion undergoes anodic oxidation to hydrogen, the copper compound undergoes cathodic reduction to copper metal, and, simultaneously, the electron and hydrogen are transferred to a nonionized formaldehyde molecule to yield methanol. Mathematical models are suggested for the reactions. The effective rate constants and activation energies of the slow steps of the reactions have been determined. The effective rate constants of the noncatalytic reduction reactions of the copper compounds and the ratios of the rates of the rapid hydrogen and methanol formation reactions have been estimated.     

Relationship between Coordination Structure and Biological Activity of Copper(II) Nicotinate

1 INTRODUCTION In 1945, Braude[1] found for the first time that adding copper (Cu) ten times the normal requisite amount into the feed can improve the production property of the animal obviously. Therefore, from then on copper has been widely applied in pig- breeding industry as an effective growth-promoting agent, especially in the process of intensive culture, which plays an important part in improving the growth of animal and the production property. However, at the same time, the high…