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1.
A new method for preparing hydrophobic nano-copper powders 总被引:1,自引:0,他引:1
Yang Jian-guang Zhou Yuang-lin Takeshi Okamoto Ryoichi Ichino Masazumi Okido 《Journal of Materials Science》2007,42(18):7638-7642
A novel chemical process for producing hydrophobic nano-copper particles with satisfied anti-oxidation property is described
here. The resultant particles have been characterized by X-ray diffraction, size distribution analysis and SEM, TEM observation.
Well-dispersed nano-copper particles with c.a. 30 nm in diameter were obtained from the water/organic solution containing
0.2M Cu2+ ion, glucose as the first reductant, ascorbic acid as the second reductant. In this process, oleic acid acted as both a phase-transfer
agent and a particle protector coordinating their carboxyl end groups on the new generated copper particles surface, the hydrophobic
carbon tails of the oleic acids were pointed outwards from the surface of the synthesized particles. This organic film seems
to play an important role for prevent the new generated copper particles from oxidation. In addition, this process also adopting
two-step reduction method can lead compulsively disconnect nucleation and nucleation growth, and weaken conventional eruptible
nucleation. By controlling the first reduction product’s size, this process is more convenient for delaying the nuclei processes
and for controlling the ultimate copper particles size. 相似文献
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在含有硅超微粒子的电解液中,采用电化学方法对铝或铝合金进行一次电解,在其表面获得掺硅复合氧化膜,并在含有混合金属盐和硅配合体系中进行二次电解着色,获得具有高防护性的彩色复合铝氧化膜.测试结果表明:一次电解形成的掺硅复合氧化膜中硅的存在形式主要是NaAlSi3O8长石型结构,二次电解着色后,膜层中硅的存在形式主要是Ag8SiS6;膜的表观密度为3.53 g·cm-3、孔隙率10.6%、膜厚大于20 μm;336 h耐盐雾实验腐蚀评级为10级,1O周期(240h)的耐交变湿热实验试片膜层无变化,28 d(672 h)耐霉菌实验长霉为0级,连续1 Y(365天)自然气候暴露实验腐蚀评级为10级. 相似文献
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Ceramic–metal composites (cermets) containing yttria-stabilized zirconia(YSZ) and Ni particles as anode materials in solid
oxide fuel cells were prepared by a new method. The method encompasses nickel oxalate dihydrate precipitation on the nanometre
YSZ powder, and decomposition at 633 K in inert atmosphere. The composite powders containing 30, 40, and 50% Ni manufactured
by the oxalate method were compacted into disk pellets, and sintered in Ar containing 10% H2. The structure of the cermet materials was characterized by means of X-ray diffractometry (XRD), scanning electron microscopy
(SEM), and mercury porosimetry. The thermal expansion coefficient (TEC) was determined by the dilatometric method. Electrochemical
impedance spectroscopy (EIS) was used to determine electrical conductivity. The oxalate method leads to obtaining the Ni/YSZ
anodes with the Ni content reduced to 40 wt% and well obeying based requirements for anode material in SOFCs. 相似文献
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A simple method was developed for producing graphenes by quenching hot graphite rod in aqueous solutions. The products were mixtures of 2-4 layer graphenes that were confirmed by HRTEM and AFM measurements. XPS, EDX and FTIR analyses gave low oxygen contents in the products. The quenching stresses promoted the exfoliation of graphite into graphenes. Because the oxidation occurred on the surface of graphite rod, the obtained graphenes only exhibited low oxygen pollution. DMF solutions were optimised as the best quenching medium. High-quality graphenes could also be produced in NaOH solution with a suitable concentration. This quenching route implied the possibility to be scaled up into a continuous strategy for graphenes. 相似文献
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A method for preparing ferric activated carbon composites adsorbents to remove arsenic from drinking water 总被引:3,自引:0,他引:3
Iron oxide/activated carbon (FeO/AC) composite adsorbent material, which was used to modify the coal-based activated carbon (AC) 12 x 40, was prepared by the special ferric oxide microcrystal in this study. This composite can be used as the adsorbent to remove arsenic from drinking water, and Langmuir isotherm adsorption equation well describes the experimental adsorption isotherms. Then, the arsenic desorption can subsequently be separated from the medium by using a 1% aqueous NaOH solution. The apparent characters and physical chemistry performances of FeO/AC composite were investigated by X-ray diffraction (XRD), nitrogen adsorption, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Batch and column adsorption experiments were carried out to investigate and compare the arsenic removal capability of the prepared FeO/AC composite material and virgin activated carbon. It can be concluded that: (1) the main phase present in this composite are magnetite (Fe(3)O(4)), maghemite (gamma-Fe(2)O(3)), hematite (alpha-Fe(2)O(3)) and goethite (alpha-FeO(OH)); (2) the presence of iron oxides did not significantly affect the surface area or the pore structure of the activated carbon; (3) the comparisons between the adsorption isotherms of arsenic from aqueous solution onto the composite and virgin activated carbon showed that the FeO/AC composite behave an excellent capacity of adsorption arsenic than the virgin activated carbon; (4) column adsorption experiments with FeO/AC composite adsorbent showed that the arsenic could be removed to below 0.01 mg/L within 1250 mL empty bed volume when influent concentration was 0.5mg/L. 相似文献
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Carbon nanotube (CNT)-grafted carbon fibers (CFs) have emerged as new reinforcements for improving the mechanical properties of CF-reinforced composites but such enhancement in macroscale composites has not been realized. This paper reports a facile method for preparing CNT-grafted CFs and improving the tensile strength of their composites. A CNT/polyacrylonitrile solution was sprayed onto the surface of the CF woven fabrics, and the CNTs were grafted by a thermal treatment at 300 °C. CNT-grafted CF composites were fabricated using the CNT-grafted CF woven fabrics using a vacuum-assisted resin transfer molding process with epoxy resin. The CNT-grafted CF composite exhibited 22% enhancement in the tensile strength compared to that of the pristine CF composite. Fracture surfaces of the CNT-grafted CF composites showed that the grafted CNTs obstructed the propagation of micro-cracks and micro-delamination around the CFs and also yarn boundaries, resulting in improved tensile strength of CNT-grafted CF composites. 相似文献
10.
E. G. Il’in A. G. Beirakhov Yu. M. Kulyako T. I. Trofimov M. D. Samsonov B. F. Myasoedov 《Radiochemistry》2010,52(4):350-353
Addition of aqueous ammonia and hydroxylamine hydrochloride to a nitric acid solution containing U(VI) and Pu(VI) causes at
pH ∼7 precipitation of a mixture of U(VI) hydroxylaminate and Pu(III) hydroxide. The precipitate separated from the mother
liquor and dried at 60°C upon further calcination in air at 300°C transforms into a solid solution of PuO2 in UO2 as a result of thermal decomposition of the precipitate with the reduction of U(VI) to U(IV) by the ligand coordinated to
the uranyl ion. The developed procedure for preparing mixed U-Pu dioxide can become an alternative to the presently used method
for preparing uranium dioxide and mixed uranium-plutonium oxide fuel (MOX fuel) by heating at 800–900°C in a reducing atmosphere. 相似文献
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In this work, we have proposed a simple, cost-effective and green method for the production of 3D hierarchical carbide derived carbon by single step molten salts electrolysis at 710°C. During the electrolysis process, the high carbon ferromanganese fed manganese and iron ions into molten salts and then those ions were reduced on cathode. At last, there is only porous left on the anode. By XRD and Raman analysis, it was found that the as-prepared porous carbon is composed of amorphous carbon and ordered graphitic carbon with a high degree of graphitization. SEM, TEM and N2 sorption measurement indicate that this type of CDC has a multimodal pore system consisting of micro-pores, meso-pores and macro-pores. 相似文献
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Yuan Feng Wei Sun Zhichao Lou Qiuyi Wang Yihan Zhao Yanjun Li 《Journal of Materials Science: Materials in Electronics》2021,32(21):26137-26150
Journal of Materials Science: Materials in Electronics - With the progress of science and technology and the improvement of people’s living standards, the high-value utilization of waste... 相似文献
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In this paper, a new and innovative process for assembling chains of carbon nanofibers (CNFs) in epoxy, uniquely different from those generally used for chaining particles in a liquid medium, is presented. Chains of aligned CNFs are assembled in a region rich in CNFs and extended into regions where there are no CNFs. A physical explanation of the process is provided based on the conductive nature of the CNFs. By contacting the chains with the electrodes, the process of chain growth is expedited and well-ordered parallel chains with equal?spacing are grown over distances of 2?cm. 相似文献
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Wharton JE Jin P Sexton LT Horne LP Sherrill SA Mino WK Martin CR 《Small (Weinheim an der Bergstrasse, Germany)》2007,3(8):1424-1430
There is increasing interest in using nanopores in synthetic membranes as resistive‐pulse sensors for biomedical analytes. Analytes detected with prototype artificial‐nanopore biosensors include drugs, DNA, proteins, and viruses. This field is, however, currently in its infancy. A key question that must be addressed in order for such sensors to progress from an interesting laboratory experiment to practical devices is: Can the artificial‐nanopore sensing element be reproducibly prepared? We have been evaluating sensors that employ a conically shaped nanopore prepared by the track‐etch method as the sensor element. We describe here a new two‐step pore‐etching procedure that allows for good reproducibility in nanopore fabrication. In addition, we describe a simple mathematical model that allows us to predict the characteristics of the pore produced given the experimental parameters of the two‐step etch. This method and model constitute important steps toward developing practical, real‐world, artificial‐nanopore biosensors. 相似文献
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首次以甲醇/水为溶剂合成壳寡糖季铵盐型基因载体,并采用1 H NMR表征技术对合成条件进行了研究。结果表明,反应溶剂、NaOH浓度、CH3I用量、反应时间、一步法/两步法合成步骤等都会影响壳寡糖季铵盐的合成。甲醇/水溶剂比NMP溶剂更有利于壳寡糖季铵盐产品的控制、减少副反应的发生;适量的NaOH浓度,有利于壳寡糖季铵盐的合成,NaOH浓度过低,不利于季铵盐的生成,NaOH浓度过高,易发生壳寡糖3,6位-OH的甲醚化副反应;足够量的CH3I和反应时间及两步法合成步骤有利于壳寡糖季铵盐的合成。本研究为具有潜在临床应用价值的壳寡糖季铵盐基因载体提供了一种低碳、绿色、经济、环境友好的合成新方法。 相似文献
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Graphene nano-sheets (GNs) with high quality were successfully synthesized in a Teflon-lined container through a low temperature expansion process. The influence factors of expansion temperature, expansion mode and reduction time on the morphology and structure of products have been systematically investigated, and an optimum experimental condition for the synthesis of GNs has been obtained. The results showed that the Teflon-lined container is an effective apparatus for preparing GNs at relative low temperature (<300 °C). The low temperature synthetic process is simple, inexpensive and easy to scale up in comparison with the traditional method which often consume more energy, use more complicated instruments, or more costly. The electrochemical properties of the as-synthesized products were investigated as anode materials for lithium ion batteries. 相似文献
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A surfactant-free, template-less and seed-less method, namely the thermal-assisted photoreduction (TAP) process, has been developed to synthesize vertically grown Au nanowires (30-80?nm in diameter and about 2?μm in length) on the surface of thin film titanium dioxide (TiO(2)), which is locally excited by blackbody radiation. The Au nanowires thus produced are single-crystalline with a preferred [Formula: see text] growth direction. The electrical behavior investigated using a nanomanipulation device indicates that the Au nanowires possess an excellent electrical resistivity of about 3.49 × 10(-8)?Ω?m. 相似文献