Wei CHEN
,
Zhaojun LIN
,
Zhanguo WANG
,
Yan XU and Lanying LIN (Lab. of Semicond. Mater. Sci.
,
Institute of Semiconductors
,
Chinese Academy of Sciences
,
Beijing 100083
,
China )
材料科学技术(英文)
CdS nanoparticles were prepared in air and their stability by air annealing was studied. A small change in crystal structure and particle size was observed by air annealing, but a rapid reduction in fluorescence was found. Through investigation, it is revealed that it is the surface change or reconstruction rather than the variation of the size or structure that decreases the fluorescence.The emission of the particles consists with two peaks which are dependent on the excitation energy. The two peaks are considered to be arisen from "two" different sizes of nanoparticles and may be explained in terms of selectively excited photoluminescence. Finally we discuss why the discrete state of nanoparticles are able to be resolved in the photoluminescence excitation spectrum, but could not be differentiated in the absorption spectrum.
关键词:
Composites Science and Technology
Short glass fiber-reinforced nylon 6,6 with and without rubbery inclusions were injection molded into standard specimens. The mechanical properties and the residual fiber length distribution were measured. The macro-to-micro model proposed by Bowyer and Bader [J. Mater. Sci., 7 (1972) 1315] was used to determine the interfacial shear strength (IFSS). The IFSS in the toughened nylon 6,6-based composites was found to be superior to that in the untoughened nylon 6,6-based composites. This indicates that the presence of rubbery phase in the composite system contributed to the interfacial bonding between nylon 6,6 and glass fibers (GF). Back-scattered electron imaging taken on a plane perpendicular to the mold filling direction for fiber-reinforced toughened nylon 6,6 showed that the rubbery phase adhered to the GF surface. This morphological feature was regarded as a main factor responsible for the improvement of IFSS in the reinforced toughened nylon 6,6 composites. (C) 2004 Published by Elsevier Ltd.
关键词:
glass fiber;nylon 6,6;reinforced polymers;glass;strength;behavior;microstructures;thermoplastics
Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
By cyclically deforming a [(5) over bar 913]perpendicular to[(5) over bar 79] copper bicrystal with a perpendicular grain boundary (GB), the fatigue crack initiation and fracture behavior were investigated. It was found that only the primary slip systems were activated on both G1[(5) over bar 913] and G2[(5) over bar 79] grains including the vicinity of the GB at axial plastic strain range of 1.8 x 10(-4)-2.56 x 10(-3). By observing the surface and fractography, it was confirmed that the fatigue cracks always nucleated and propagated along the GB, and displayed an obvious tendency on different surfaces. On the front surface of the bicrystal, the intergranular cracking was more preferential than that on the lateral surface, even though the geometrical conditions among PSB, GB and stress axis on the lateral surface claimed to enhance cracking are more close to those proposed by Christ (Mater. Sci. Eng. A117 (1989) L25). Based on the experimental results above, the effect of the interaction of PSB with GB and stress axis on intergranular fatigue cracking in the bicrystal is discussed. It is suggested that Christ's geometrical conditions for intergranular cracking might be further developed and the plastic strain incompatibility near the GB should play a more important effect on intergranular fatigue cracking. (C) 1999 Elsevier Science S.A. All rights reserved.
关键词:
copper bicrystal;cyclic deformation;grain boundary;fractography;intergranular cracking;nucleation
中国腐蚀与防护学报
由中国金属学会主办、中国科学院金属研究所承办的英文期刊ActaMetallurgicaSinica(EnglishLettersl于近日通过ThomsonReuters的评审,入选SCI数据库。该刊自2009年起出版的论文被ThomsonReuters旗下的ScienceCitationIndexExpanded(alsoknownasSeiSeareh),JournalCitationReports/ScienceEdition和CurrentContents@/EngineeringComputingandTechnol-ogy所收录。这是继(《金属学报》和《材料科学技术(英文版)》之后,金属所承办的又一被SCI收录的期刊。
关键词:
SCI
,
中国科学院金属研究所
,
中国金属学会
,
英文期刊
,
材料科学技术
,
数据库
中国腐蚀与防护学报
由中国金属学会主办、中国科学院金属研究所承办的英文期刊ActaMetallurgicaSinica(EnglishLettersl于近日通过ThomsonReuters的评审,入选SCI数据库。该刊自2009年起出版的论文被ThomsonReuters旗下的ScienceCitationIndexExpanded(alsoknownasSeiSeareh),JournalCitationReports/ScienceEdition和CurrentContents@/EngineeringComputingandTechnol-ogy所收录。这是继(《金属学报》和《材料科学技术(英文版)》之后,金属所承办的又一被SCI收录的期刊。
关键词:
SCI
,
中国科学院金属研究所
,
中国金属学会
,
英文期刊
,
材料科学技术
,
数据库
Physica E-Low-Dimensional Systems & Nanostructures
Generally, phase transfer of metal nanoparticles between aqueous phase and organic phase need two reagents at last. One is stabilizer of nanoparticles, the other is phase-transfer agent (Chem. Lett. 21 (1992) 1527; J. Colloid Interface Sci. 161 (1993) 471; J. Phys. Chem B 101 (1997) 9876; Chem. Commun. (1997) 537; Langmuir 14 (1998) 602; J. Phys. Chem B 103 (1999) 7238; Chem. Mater. 13 (2001) 4692; Langmuir 17 (2001) 733; Langmuir 16 (2000) 9775; Langmuir 18 (2002) 3364; J. Am. Chem. Soc. 123 (12001) 11148). In this paper, Ag nanoparticle prepared by tannic acid reduction of AgNO3 in aqueous medium were transferred to chloroform solution via a remarkably simple one-step route under the effect of phase-transfer inducer dimethyldioctadecylammonium chloride (DDAC), where no special stabilizer was required. Monolayer of Ag nanoparticles is obtained on carbon film by self-assembly using chloroform organosol. The effect of the inducer DDAC concentration is checked, and it was found that 5 x 10(-3) mol dm(-3) of DDAC was the optimum concentration for phase transfer of Ag nanoparticles. The organosol, Ag nanoparticle self-assembled monolayer and phase transfer were characterized by UV-vis spectra, TEM, ED and TF-IR. (C) 2004 Elsevier B.V. All rights reserved.
关键词:
silver;nanostructures;UV-Vis spectroscopy;DDAC;organosol;modified gold nanoparticles;shape-controlled synthesis;silver;nanoparticles;colloidal gold;aspect-ratio;nanorods;toluene;nanodisks;platinum;water
腐蚀学报(英文)
由中国金属学会主办、中国科学院金属研究所承办的英文期刊Acta Metallurgica Sinica(English Letters)于近日通过Thomson Reuters的评审,入选SCI数据库.该刊自2009年起出版的论文被Thomson Reuters旗下的Science Citation Index Expanded(alsoknownas Sci Search),Journal Citation Reports/science Edition和Current Contents/Engineering Computingand Technology所收录.这是继《金属学报》和《材料科学技术(英文版)》之后,金属所承办的又一被SCI收录的期刊
关键词:
SCI
,
中国科学院金属研究所
,
Thomson
,
中国金属学会
,
Edition
,
英文期刊
,
材料科学技术
,
数据库
腐蚀学报(英文)
由中国金属学会主办、中国科学院金属研究所承办的英文期刊Acta Metallurgica Sinica(English Letters)于近日通过Thomson Reuters的评审,入选SCI数据库.该刊自2009年起出版的论文被ThomsonReuters旗下的Science Citation Index Expanded(also known as SciSearch),
关键词:
SCI
,
中国科学院金属研究所
,
Thomson
,
中国金属学会
,
英文期刊
,
数据库