共查询到20条相似文献,搜索用时 31 毫秒
1.
《中国标准化(英文版)》2007,(4)
From May 28th to June 1st, 2007, the Standardization Administration of the People's Republic of China (SAC) organized a series of cooperation activities with the American Institute of Standards and Technology (NIST) and the American National Standards Institute (ANSI). 相似文献
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The resistivity and magnetic susceptibility ofthe quenched samples for the Y-Ba-Cu oxideswere measured at room temperature.Themeasurement for the temperature dependence of theamorphous Bi-Sr-Ca-Cu oxides with differentheat treatment temperature was made.Theresistivity and the parameters C in the formulax=X_0+C/(T-0)of the quenched samples forY-Ba-Cu oxides decreased with lowering quenchtemperature,and their susceptibility did not varymonotonously with quench temperature.The tem-perature dependence of the amorphousBi-Sr-Ca-Cu oxides gradually deviates fromCurie-Weiss law with increasing heat treatmenttemperature.The local magnetic moments forY-Ba-Cu and amorphous Bi-Sr-Ca-Cu oxidesgradually decrease with decreasing quench tempera-ture or increasing heat treatment temperature. 相似文献
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Oxide and Sulfide Dispersive Precipitation and Effects on Microstructure and Properties of Low Carbon Steels 总被引:12,自引:0,他引:12
Electron microscopic investigation on low carbon steel strips produced by the CSP process has been carried out.Large number of oxide dispersive precipitates have been observed in the ferrite matrix of the steel strips.Dimension of them is about 10-20nm.Electron diffraction study showed that the structure of these precipitates consists with cubic system spinel structure .Their lattice parameter is about 0.83nm.The results implied that they should be complex oxides of Fe,Al et al.Small sulfide particles with 100-300nm in size have also been observed.Remarkable strengthening and grain refinement effects can be obtained by the precipitations.The oxygen and sulfur in steels could play beneficial role under certain conditions. 相似文献
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Knut Blind 《中国标准化(英文版)》2006,(4)
Economic Rationales of Patents and Standards The ambivalence of patents and standards for technological development is triggered off by two different economic mechanisms: The inventors are awarded exclusive property rights, because: 1) additional incentives for the production of new 相似文献
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Seventeen samples from paintings by the distinguished 19th century Portuguese painter, Henrique Pous?o, were characterized by micro-X-ray diffractometry and infrared and Raman microspectroscopy. The main advantages and limitations of each technique for pigment identification are outlined, revealing the need for the use of complementary techniques. Pous?o's palette is discussed. 相似文献
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In this paper,a new thermographic methodbased on the measurement of infrared emission(IR)from the surface of loaded body has been used tostudy the cooling and heating in aluminium andsteel specimens under tensile and cyclic loading.Atypical test procedure using infrared to measurethermographic changes near the crack tip and theimmediate surrounding area is described.In addi-tion,a procedure for determining the stress concen-tration near the crack tip is also presented.Resultsare given for thermoelastic cooling phenomenon ofmetals during the tensile process and IR coolingand IR heating emissions at the crack tip duringcyclic loading.Attention is drawn to the multiplephenomenon of IR cooling emission in the receivedsignal as the applied load range increases beyondthe elastic limit of both metals.A new applicationof the IR technique to the determination of the po-sition of crack tip during cyclic loading is also pres-ented. 相似文献
11.
Akira Doi 《Journal of Materials Science》1989,24(3):911-914
Reported complex impedance and admittance data for yttria-stabilized zirconia and-alumina have been studied in the light of information obtained from an ion-conducting glass. From the analysis it was found that the a.c. response of those crystalline electrolytes resembles that of a glass; namely, apart from complications such as grain boundaries and second phases, the universal nature which prevails in solid electrolytes is a change of an equivalent circuit from a parallelRC to a seriesRC circuit with increasing temperatures as a result of formation and development of the charge-carrier-depleted region near the electrode as ionic conduction proceeds. 相似文献
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Xu Bin 《中国标准化(英文版)》2008,27(3):4-8
Preface:Nowadays, standardization is playing a more crucial role in marketing, industrial and tech- nical fields. Twenty years ago, standardization was the realm of just a few specialists.Today, compa- nies treat standardization as a technical and com- mercial element of great importance. At the same time, companies have realized they must play an active role in the standardization field,and they must be ready to accept standards made without their agreement.Therefore,it is also increasingly necessary for engineers and decision makers in en- terprises to study the purpose and application of standards and standardization, and to optimize their enterprises’ position by doing so. 相似文献
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Junchao TAO Yue SHEN Feng GU Jinzhuan ZHU Jiancheng ZHANG 《材料科学技术学报》2007,23(4):513-516
Well-organized mesoporous titania particles and thin films were successfully synthesized by using tetrabutyl titanate as the inorganic precursor and triblock copolymer (Pluronic P123) as the template via evaporationinduced self-assembly process. The resulting materials were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD). Fourier-transform infrared spectroscopy (FT-IR),Brunauer-Emmett-Teller (BET) and atomic force microscopy (AFM). Macro shape of mesoporous titania would greatly influence the mesostructure of materials, and the probable reasons were also discussed. 相似文献
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《工程(英文)》2015,(2)
<正>Ⅲ-nitride light-emitting diodes(LEDs)are now used almost everywhere,due to their energy-saving capability.In the near future,the vast majority of lighting sources will undoubtedly be based on LEDs.What future technologies and applications can we expect from Ⅲ-nitride-based and particularly gallium nitride(Ga N)-based,materials and devices? 相似文献
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Computer experiments were performed on simulated polycrystalline material samples that possess locally anisotropic microstructures to investigate stress intensity factor ( K ) variations and anisotropy along fronts of microcracks of different sizes. The anisotropic K , arising from inhomogeneous stresses in broken grains, was determined for planar microcracks by using a weight function-based numerical technique. It has been found that the grain-orientation-geometry-induced local anisotropy produces large variations in K along front of microcracks, when the crack size is of the order of few grain diameters. Synergetic effect of grain orientation and geometry of broken grains control K variations and evolution along the microcrack front. The K variations may diminish at large crack sizes, signifying a shift of K calculation to bulk stress dependence from local stress dependence. Local grain geometry and texture may lead to K anisotropy, producing unusually higher/lower K at a segment of the crack front. Either K variation or anisotropy cannot be ignored when assessing a microcrack. 相似文献
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Liang LI Guanghai LI Xiaosheng FANG 《材料科学技术学报》2007,23(2):166-181
This article reviews the recent developments in the fabrication and properties of one-dimensional (1D) Bi-based nanostructures, including Bi, Sb, BixSb1-x and Bi2Te3 nanowire arrays, and Bi-Bi and Bi-Sb nanojunction arrays. In this article, we present an efiective method to fabricate Bi nanowire arrays with difierent diameters in anodic alumina membrane (AAM) with a single pore size by the pulsed electrodeposition. The fabrication of the high-filling and ordered Bi1-xSbx and Bi2Te3 single crystalline nanowire arrays, the Bi nanowire metalsemiconductor homojunction and Bi-Sb nanowire metal-semiconductor heterojunction arrays by the pulsed electrodeposition are reported. The factors controlling the composition, diameter, growth rate and orientation of the nanowires are analyzed, and the growth mechanism of the nanowire and nanojunction arrays are discussed together with the study of the electrical and thermal properties of Bi-based nanowires and nanojunctions.Finally, this review is concluded with some perspectives on the research directions and focuses in the Bi-based nanomaterials fields. 相似文献
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The collapse and stability of carbon nanotubes (CNTs) have important implications for their synthesis and applications. While nanotube collapse has been observed experimentally, the conditions for the collapse, especially its dependence on tube structures, are not clear. We have studied the energetics of the collapse of single-?and multi-wall CNTs via atomistic simulations. The collapse is governed by the number of walls and the radius of the inner-most wall. The collapsed structure is energetically favored about a certain diameter, which is 4.12, 4.96 and 5.76?nm for single-, double-?and triple-wall CNTs, respectively. The CNT chirality also has a strong influence on the collapsed structure, leading to flat, warped and twisted CNTs, depending on the chiral angle. 相似文献
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Kuang-Kuo Wang 《Thin solid films》2010,518(23):6945-1386
The orientation relationships and interfaces of δ-AuSn with the Au (001), (110) and (111) surfaces have been studied with transmission electron microscopy. Au was evaporated onto the NaCl (001), (011) and (111) surfaces to form epitaxial Au thin films and Sn was evaporated onto the Au films to form δ-AuSn. Two types of orientation relationships have been found: (1) δ//(001)Au, (0001)δ//(110)Au, and δ//Au, which was found on the δ/(001)Au interface and the δ/Au interfaces; and (2) δ//Au, (0001)δ//(110)Au, and δ//Au, which was found on the δ/Au interface. The interfaces are analyzed by the structures of the surfaces and the orientation relationships. The nucleation of δ-AuSn on these interfaces is also discussed. 相似文献
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In an idealised industrial ecosystem (IE), firms and organisations utilise each other's material and energy flows including wastes and by-products to reduce the system's virgin material and energy input as well as the waste and emission output from the system as a whole, and contribute to sustainable development (SD). IE complements the more conventional individual flow, product, process, organisation, individual actor or sector-focused environmental management approaches and tools with network or systems level approaches. The first research objective of this paper is to construct indicators for IE. The second task is to test the use of these indicators with "what if?" material and energy flow scenarios for the energy and waste system of Satakunta region in Finland including 28 municipalities. Using literature analysis as a source, we arrive at environmental indicators of carbon dioxide (CO2) equivalents, and at economic indicators of fuel, energy and waste management costs and revenues. The social indicators show the employment effects of the waste management system. The scenarios analyse the current situation (0-scenario) against alternative situations in the future. The future scenarios are developed according to the known and anticipated trends in international and national policy and legislation. The indicator application in the scenarios produces social, environmental and economic effects of waste management in four categories: direct negative, direct positive, indirect negative and indirect positive. Industrial ecosystem theory emphasises the utilisation of wastes as a resource with value alongside the objective of reducing waste. Therefore, the indirect positive effects of waste management are important, as well as the conventional focus of waste management, which has usually been on direct positive effects. The main difficulties in our argument are the system boundary definition, the qualitatively different nature of environmental, economic and social effects and indicators as well as the lack of qualitative or interview data on the preferences and interests of the actors involved. 相似文献