采用不同方法合成CuS纳米粒子研究

分别采用水热合成法及微乳液法制备了纳米CuS粒子。以醋酸铜和升华硫为原料配成稳定溶液,进行水热合成得到纳米CuS粒子;以表面活性剂十六烷基三甲基溴化铵(CTAB)、有机溶剂正庚烷、水和助表面活性剂正丁醇组成的W/O型微乳体系,在加热状态下合成纳米CuS粒子。并采用UV-VIS、XRD和TEM等分析手段对粉体进行了表征。     

溶剂稳定的铜纳米颗粒的制备

以乙二醇为溶剂、硼氢化钾为还原剂制备了溶剂稳定的铜纳米颗粒.以紫外可见光谱研究了制备铜纳米颗粒的最佳还原剂与硫酸铜之摩尔比,以透射电子显微镜对在最佳条件下制备的铜纳米颗粒进行了表征.实验表明,硼氢化钾与硫酸铜的摩尔比较小更利于制备粒径小、粒径分布窄、团聚程度低的铜纳米颗粒.     

Current methods for the identification and quantitation of ceramides: An overview

Ceramides are key compounds in the metabolism of sphingolipids and are emerging as important second messengers for various cellular processes including cell cycle arrest, differentiation, senescence, apoptosis, and others. Because of their important biological functions, exact analysis of their molecular species and concentrations is crucial for elucidating their function and metabolism. Toward this goal, several methods have been developed for the identification and quantitation of cellular ceramide levels. Methods have been developed utilizing thin-layer or high-performance liquid chromatography. Mass spectrometry also has become increasingly utilized. The Escherichia coli diacylglycerol kinase assay is one of the most frequently used techniques for ceramide quantitation. This review presents a current summary of methods used for the identification and quantitation of ceramides.     

粒径可控的铜纳米粒子的液相还原法制备

在一定温度的水溶液中,采用铜离子前躯体,水合肼为还原剂,在PVP存在下,进行了粒径、形貌可控的纯铜纳米粒子的合成,获得了粒径在7～70nm的铜纳米粒子.通过X射线衍射仪、紫外一可见分光光度计、透射电子显微镜、扫描电子显微镜和电子衍射等手段对产物测试与表征,证实了上述结果.同时证明,粒径可由奥斯瓦尔德老化过程控制,保护剂可在一定程度上控制粒子形貌.     

Joining methods for plastics and plastic composites: An overview

Joining of plastics and plastic composites is becoming important because of the emerging structural applications of these materials. While providing an overview of all joining methods, this paper emphasizes the welding of thermoplastic materials. Different welding techniques, together with their main advantages and disadvantages, are briefly described. A selective bibliography, in which the 259 references have been arranged chronologically for each technology type, provides a guide to the literature.     

An overview of robust methods in medical research

Robust statistics is an extension of classical parametric statistics that specifically takes into account the fact that the assumed parametric models used by the researchers are only approximate. In this article, we review and outline how robust inferential procedures may routinely be applied in practice in the biomedical research. Numerical illustrations are given for the t-test, regression models, logistic regression, survival analysis and ROC curves, showing that robust methods are often more appropriate than standard procedures.     

An overview on methods for the production of carbon nanotubes

Carbon nanotubes (CNTs) are one of the most exciting discoveries in nanoscale sciences. A brief survey of experimental work directed towards the synthesis of CNTs has been discussed. The various methods of production of CNTs are explained outlining their capabilities, efficiencies and possible exploitation as economic large scale production. Among the discussed techniques, the chemical vapor deposition (CVD) appears to be the most potential way to produce high quality of CNTs at high yield. The advantages of CVD over other techniques are also explained and the effects of process parameter on the synthesis of these nanomaterials are discussed.     

Synthesis of highly stable dispersions of copper nanoparticles using sodium hypophosphite

Highly stable dispersions of copper nanoparticles with an average diameter of 80 nm were synthesized using a straightforward and cost‐effective method in the presence of polyvinylpyrrolidone (PVP) as a stabilizer and without any inert gas protection. Sodium hypophosphite was used as the reducing agent in low pH value aqueous medium. The copper nanoparticles were characterized by ultraviolet‐visible spectroscopy and scanning electron microscopy. The mechanism of the PVP on the stabilization of copper nanoparticles is also discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

An overview on fabrication methods for polymer optical fibers

An overview of the most important materials and fabrication methods for polymer optical fibers is given. In addition to conventional fabrication methods a newly developed continuous melt spinning process for graded‐index fibers is presented that uses rapid cooling in a water quench for the profile formation. The approaches presented are divided into continuous and discontinuous processes for step‐ and graded‐index profile fibers as well as microstructured polymer optical fibers. The methods are described in detail and discussed concerning their efficiency, quality of produced fibers and scalability. © 2014 Society of Chemical Industry     

An overview of group sequential methods in longitudinal clinical trials

During the last decade, several papers have been published on group sequential methods in general and on sequential longitudinal clinical trials in particular. This paper gives an overview of the proposed methods, emphasizing longitudinal clinical trials. Furthermore, it tries to answer some practical questions that may arise during the conduct of interim analyses in longitudinal trials. Simulations have been carried out to obtain insight in these practical considerations.     

表面修饰纳米铜颗粒添加剂的摩擦学性能

采用液相还原两步法制备了表面修饰的铜纳米颗粒,采用美国产UMT-3摩擦试验机进行四球长时抗磨实验,考察了其作为150N基础油添加剂的抗磨减摩性能及对钢球磨损表面的修复作用,用SEM和EDS分析了磨损表面的形貌和元素组成.结果表明,经过表面修饰的纳米铜颗粒作为添加剂能显著改善150N基础油的抗磨减摩性能.含4%纳米铜颗粒...     

Two-mode clustering methods: a structured overview

In this paper we present a structured overview of methods for two-mode clustering, that is, methods that provide a simultaneous clustering of the rows and columns of a rectangular data matrix. Key structuring principles include the nature of row, column and data clusters and the type of model structure or associated loss function. We illustrate with analyses of symptom data on archetypal psychiatric patients.     

Synthesis and characterization of sol-gel bioactive glass nanoparticles doped with boron and copper

In this work the sol-gel synthesis of bioactive glass nanoparticles containing both boron and copper oxides is reported for the first time in the literature. Two acid/base co-catalysed methods were compared. The obtained glasses have been characterized in terms of morphology, composition, particle surface area, phase analysis and bioactivity in acellular simulated body fluids. The almost spherical nanoparticles (<100 nm diameter) obtained are characterized by a certain degree of aggregation and have compositions, which are coherent with the theoretical ones. Each glass revealed the ability to promote the growth of hydroxyapatite on its surface during soaking in simulated body fluid, thus we can assume that the addition of boron and copper did not negatively affect the bioactivity of the sol-gel derived glasses. Future investigations will be devoted to biological characterizations for cytotoxicity, antibacterial properties and pro-angiogenetic abilities.     

SHS extrusion: An overview

Overviewed is the state-of-art in the science and technology for extrusion of still hot SHS products (also termed SHS extrusion). Addressed are the experimental and theoretical studies on rheological behavior of materials with a limited duration of their ductility. The structures/properties of extruded materials and items are also presented and discussed. Presented are the examples of practical implementation of the process to production of rod-like electrodes for electrospark alloying from new multifunctional materials, such as nanograined cermets, MAX compounds, and intermetallics.     

Green composites: An overview

The use of natural fibers to reinforce polymers is a well‐established practice, and biocomposites are increasingly used in sectors such as automotive and construction. Green composites are a specific class of biocomposites, where a bio‐based polymer matrix is reinforced by natural fibers, and they represent an emerging area in polymer science. This work discusses the environmental benefits deriving from the use of natural fibers in polymer composites and from substitution of oil‐derived polymers by bio‐based polymers as matrix material. New trends in the selection of natural fibers, that is, from waste rather than from valuable crops are described. Recently developed thermoplastic and thermosetting bio‐based polymers are reviewed, and commercially available green composites obtained thereof are discussed. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Models of SHS: An overview

The theoretical models of SHS based on lamellar or cellular approximations of the heterogeneous reactive media are comparatively analyzed. It is shown that the ratio of the reaction time to the characteristic time of heat transfer between particles is a decisive parameter for the combustion wave propagation. When the time of reaction is shorter than the time of heat exchange, the combustion occurs in a discrete mode; in the opposite case, a quasi-homogeneous combustion mode occurs. Development of the discrete cellular model does not discard the quasi-homogeneous approach but markedly extends the scope of combustion theory. This extension enables explanation of many old and new experimental results that could not be rationalized within the framework of homogeneous theory.      

Synthesis,growth mechanism and thermal stability of copper nanoparticles encapsulated by multi-layer graphene

Copper nanoparticles encapsulated by multi-layer graphene have been produced in large quantity (in grams) by metal-organic chemical vapor deposition at 600 °C with copper(II) acetylacetonate powders as precursor. The obtained graphene/copper shell/core nanoparticles were found to be formed by a novel coalescence mechanism that is quite different from the well-known dissolution–precipitation mechanism for some other graphene/metal (such as nickel, iron or cobalt) shell/core nanoparticles. Differential scanning calorimetry and thermogravimetric analyses showed that the copper nanoparticles encapsulated by multi-layer graphene with a thickness of 1–2 nm were thermally stable up to 165 °C in air atmosphere. Moreover, high-resolution transmission electron microscopy showed that the single-crystal copper nanoparticles, after exposure to air for 60 days, did not exhibit any sign of oxidation.     

SHS in Italy: An overview

In this work, the evolution of SHS research and development taking place in Italy during the last twenty years are addressed. The activity performed by the Italian research groups involved in this field that belong to the Universities of Cagliari, Genoa, Pavia, and Sassari, Polytechnic of Turin, and National Research Council IENI-Milan, respectively, are presented. The major results obtained from both the modeling and experimental points of view are reviewed while highlighting the international collaborations of each research group. Presented at the International Conference on Historical Aspects of SHS in Different Countries, October 22–27, 2007, Chernogolovka, Moscow, Russia.