共查询到20条相似文献,搜索用时 15 毫秒
1.
The present paper summarizes the development of miniaturized small-punch (SP) and TEM-disc (TD) testing techniques and shows their applicability in characterizing the mechanical properties of irradiated materials. The yield strength, ductility and fracture toughness,J
lc, were empirically estimated by analysing the deformation and fracture behaviour observed in the miniaturized specimen tests. The ductile-brittle transition temperature (DBTT) was determined from the variation of the SP or TD fracture energy with temperature. A linear correlation between the DBTT obtained from the SP and Charpy V-notched specimen tests has been theoretically and experimentally established. The problems of cracking detection and data scattering often observed in the SP or TD specimen tests are discussed in terms of heterogeneous embrittlement behaviour of materials. It has been demonstrated that these miniaturized testing techniques are capable of evaluating hardening, DBTT shifts andJ
lc decreases caused by neutron irradiation. 相似文献
2.
Preparation and optical scattering characterization of gold nanorods and their application to a dot-immunogold assay 总被引:1,自引:0,他引:1
Alekseeva AV Bogatyrev VA Dykman LA Khlebtsov BN Trachuk LA Melnikov AG Khlebtsov NG 《Applied optics》2005,44(29):6285-6295
We describe optical monitoring of the synthesis of gold nanorods (NRs) based on seed-mediated growth in the presence of the soft surfactant template cetyltrimethyilammonium bromide. To separate NRs from spheres and surfactants we fractionated samples in the density gradient of glycerol. The optical properties of NRs were characterized by extinction and differential light-scattering spectra (at 90 degrees, 450-800 nm) and by the depolarization light-scattering ratio, I(vh)/I(vv), measured at 90 degrees with a helium-neon laser. Theoretical spectra and the I(vh)/I(vv) ratios were calculated by the T-matrix method as applied to randomly oriented NRs, which were modeled by right-circular cylinders with semispherical ends. The simulated data were fitted to experimental observations by use of particle length and width as adjustable parameters, which were close to the data yielded by transmission electron microscopy. The sensitivity of the long-wavelength resonance of NRs to the dielectric surroundings was examined both experimentally and theoretically by comparison of the extinction spectra of NRs in water and in a 25% glycerol solution. Finally, we discuss the application of NR-protein A conjugates to a dot-immunogold assay with the example of biospecific staining of human IgG molecules adsorbed onto small membrane spots. 相似文献
3.
基于贝叶斯滤波的目标跟踪原理,介绍了扩展卡尔曼滤波(Extended Kalman Filter,EKF)和粒子滤波(ParticleFilter,PF)的基本思想和算法实现步骤。在非线性环境下对比分析了EKF算法和PF算法的估计精度,并给出两种方法的适用条件。EKF算法采用Taylor展开的线性变换来近似非线性模型,而PF算法采用一些带有权值的随机样本来表示所需要的后验概率密度。仿真结果表明,在强非线性非高斯环境下,PF算法的跟踪性能远优于EKF算法,当系统非线性强度不大时,EKF算法和PF算法的估计精度相差不大,但PF算法计算复杂,跟踪时间长,实时性差。 相似文献
4.
Synthesis and characterization of alumina-coated carbon nanotubes and their application for lead removal 总被引:10,自引:0,他引:10
Alumina-coated multi-wall carbon nanotubes were synthesized and characterized by scanning electron microscopy, X-ray diffraction, and FTIR. They were used as an adsorbent for the removal of lead ions from aqueous solutions in two modes, batch and fixed bed. In the batch mode, experiments were carried out to investigate the effect of contact time, agitation speed, adsorbent dosage and solution pH on the removal of lead. The coated nanotubes exhibit better removal ability over uncoated. For fixed-bed columns, thickness of the layer and flow rate were investigated. Increasing the thickness and decreasing the flow rate enhanced the removal of lead. The prepared adsorbent displayed the main advantage of separation convenience when a fixed-bed column was used compared to the batch adsorption treatment. 相似文献
5.
Target costing is a modern approach applied during product development that defines cost targets for products and its components. These cost targets are driven by customer requirements and achievable revenues. The intention of this paper is the integration of target costing with modern concepts of modelling uncertainty and management of risk based on optimisation. Contrary to the traditional focus of target costing on cost targets, this paper prefers a strategy for achieving a target profit. Moreover, in this paper target costing is understood as a continuous process with incremental changes of cost drivers, product and component design as well as product prices. Therefore, the change in costs and profit with respect to aforementioned control parameters is modelled by linear approximations. Hence, improved decisions concerning design and prices are derived by linear programming models. In practice, information concerning product and component costs, demand or customer preferences are not given with certainty. Therefore, we apply a stochastic programming approach to manage the risk inherent in the target costing process. After a general presentation, we apply our approach to the provision of an information and communication technology service where the level of uncertainty is considerable. 相似文献
6.
Un Jeong Kim Sun Il Kim Sungwoo Hwang Jaehyun Hur 《Journal of Materials Science》2014,49(24):8328-8334
We present a novel method for fabricating two-dimensional arrays of zinc oxide (ZnO) nanorod patterns. Vertically aligned ZnO nanostructure patterns were synthesized by hydrothermal growth on a two-dimensional seed layer pattern formed by atomic layer deposition. Various characteristics of ZnO seed films were experimentally studied in order to optimize the fabrication of ZnO rod structures in terms of their uniformity and vertical alignment on the two-dimensional-patterned surfaces. Using these ZnO structures as hierarchical electrodes, we demonstrate that localized electric fields in the proximity of ZnO rod patterns can be used for periodic alignment of liquid crystal molecules, resulting in the optical diffraction grating effect. Process conditions for creating ZnO rod patterns that best enhance diffraction efficiency are further discussed. The current study is the first demonstration of hierarchical ZnO rod patterns as electrodes for optical modulation of a medium. We believe this will be beneficial for future optical applications. 相似文献
7.
E. Le Bourhis 《Vacuum》2008,82(12):1353-1359
Instrumented indentation mechanics and its applications to thin film characterization are described and discussed. Instrumented nanoindentation has become an outstanding tool for characterizing coatings and treated surfaces. It is routinely used in industry and university allowing for determining the mechanical performance of coated and treated pieces, that is of primary importance for keeping new surface functionality in time. The paper reviews important procedures and concepts that have proved to be very useful to analyse the contact response (elastic unloading, indentation strains and stresses, composite response of coated pieces). Examples are used to illustrate the very wide range of studies that can be carried out. 相似文献
8.
Probabilistic analytical target cascading (PATC) is an approach for multi-level multi-disciplinary design optimization under uncertainty. In the original PATC approach, only the mean and variance of each interrelated response and linking variable are matched in a multi-level hierarchy. The ignorance of response correlation introduces difficulties in finding optimal solutions especially when the covariance of interrelated responses has a significant impact. In this article, an enhanced PATC (EPATC) approach is proposed. In addition to matching the first two statistical moments, the covariance between the interrelated responses is also considered by applying a modified updating strategy for estimating the statistical performance of an upper-level subsystem. A mathematical example and a multi-scale design problem are used to demonstrate the effectiveness and efficiency of the proposed EPATC approach. This study shows that the EPATC approach outperforms the original PATC by providing more accurate optimal solutions. 相似文献
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《Materials & Design》1988,9(3):127-134
Surfaces of materials, the top few atomic layers, are of critical importance because it is here that a material interacts with its environment. The surface properties of materials dominate their corrosion behaviour, wettability, electrical contact resistance, frictional behaviour, adhesion properties and chemical reactivity. Over the last 25 years the vital role that surfaces play and the need to characterise them have been increasingly recognised and this has been paralleled by the development of many new surface analysis techniques. Of these, just a few have become pre-eminent for materials and devices characterisation: X-ray photoelectron spectroscopy, Auger electron spectroscopy and secondary ion mass spectrometry. The principles and capabilities of each of these techniques are briefly described. Application include the study of semiconductors, metallic and ceramic materials. 相似文献
11.
The study of road safety has seen great strides over the past few decades with advances in analytical methods and research tools that allow researchers to provide insights into the complex interactions of the driver, vehicle, and roadway. Data collection methods range from traditional traffic and roadway sensors to instrumented vehicles and driving simulators, capable of providing detailed data on both the normal driving conditions and the circumstances surrounding a safety critical event. In September 2011, the Third International Conference on Road Safety and Simulation was held in Indianapolis, Indiana, USA, which was hosted by the Purdue University Center for Road Safety and sponsored by the Transportation Research Board and its three committees: ANB20 Safety Data, Analysis and Evaluation, AND30 Simulation and Measurement of Vehicle and Operator Performance, and ABJ95 Visualization in Transportation. The conference brought together two hundred researchers from all over the world demonstrating some of the latest research methods to quantify crash causality and associations, and model road safety. This special issue is a collection of 14 papers that were presented at the conference and then peer-reviewed through this journal. These papers showcase the types of analytical tools needed to examine various crash types, the use of naturalistic and on-road data to validate the use of surrogate measures of safety, and the value of driving simulators to examine high-risk situations. 相似文献
12.
Yoshihiro Hamakawa 《Thin solid films》1983,108(3):301-312
Recent developments in the physics and technology of tetrahedrally bonded amorphous semiconductors are reviewed. First, some unique advantages of these materials are discussed from the point of view of their basic physical properties and of their technological applications. The current state of the art in the development and technology of amorphous silicon solar cells is surveyed, and some new approaches and key technologies which enable efficiencies of the order of 10% to be attained are introduced. The principle advantages of photothermal conversion in p-type hydrogenated amorphous siliicon films are described. Some fundamental properties of photothermal conversion using this material are presented. Finally, a newly developed amorphous silicon photovoltaic-photothermal hybrid solar coating device with a conversion efficiency in excess of 55% is described. 相似文献
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Hirohisa Yamada Kenji Tamura Yujiro Watanabe Nobuo Iyi Kazuya Morimoto 《Science and Technology of Advanced Materials》2011,12(6)
Geomaterials are materials inspired by geological systems originating from the billion years long history of the Earth. This article reviews three important classes of geomaterials. The first one is smectites—layered silicates with a cation-exchange capacity. Smectites are useful for removing pollutants and as intercalation compounds, catalysts and polymer nanocomposites. The second class is layered double hydroxides (LDHs). They have an anion-exchange capacity and are used as catalysts, catalyst precursors, sorbents and scavengers for halogens. The third class of geomaterials is zeolites—microporous materials with a cation-exchange capacity which are used for removing harmful cations. Zeolite composites with LDHs can absorb ammonium and phosphate ions in rivers and lakes, whereas zeolite/apatite composites can immobilize the radioactive iodine. These geomaterials are essential for environmental remediation. 相似文献
15.
AbstractGeomaterials are materials inspired by geological systems originating from the billion years long history of the Earth. This article reviews three important classes of geomaterials. The first one is smectites—layered silicates with a cation-exchange capacity. Smectites are useful for removing pollutants and as intercalation compounds, catalysts and polymer nanocomposites. The second class is layered double hydroxides (LDHs). They have an anion-exchange capacity and are used as catalysts, catalyst precursors, sorbents and scavengers for halogens. The third class of geomaterials is zeolites—microporous materials with a cation-exchange capacity which are used for removing harmful cations. Zeolite composites with LDHs can absorb ammonium and phosphate ions in rivers and lakes, whereas zeolite/apatite composites can immobilize the radioactive iodine. These geomaterials are essential for environmental remediation. 相似文献
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地震曲率技术在地震资料解释中的应用 总被引:1,自引:0,他引:1
通过地震曲率属性的分析,寻找适合研究区的地震曲率,研究其解释技术。系统总结了地震曲率技术的解释应用及应注意的问题。针对小断层在常规地震剖面上表现为同相轴的微小变化、扭曲、振幅突然变弱等特征,利用这些微小的变化在地震层曲率属性上表现为线性构造,进行小断层识别,异常的长度和方向分别代表着断层的延展长度和断层的走向。二维曲率属性有比较明确的物理意义,相对一阶导数属性(如微分、倾角、方位角等),它在构造特征识别上有明显的长处。它们对刻画地质体轮廓、分层结构、断裂系统等非常有效。实例表明,地震曲率属性对断层的轨迹、沉积体边界的刻画清晰、连续,利于解释,减少解释多解性。 相似文献
18.
Crowe TW Globus T Woolard DL Hesler JL 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2004,362(1815):365-74; discussion 374-7
Terahertz spectroscopy has long been used as an important measurement tool in fields such as radio astronomy, physical chemistry, atmospheric studies and plasma research. More recently terahertz technology has been used to develop an exciting new technique to investigate the properties of a wide range of biological materials. Although much research remains before a full understanding of the interaction between biomaterials and terahertz radiation is developed, these initial studies have created a compelling case for further scientific study. Also, the potential development of practical tools to detect and identify biological materials such as biological-warfare agents and food contaminants, or of medical diagnostic tools, is driving the need for improved terahertz technology. In particular, improved terahertz sources and detectors that can be used in practical spectroscopy systems are needed. This paper overviews some of the recent measurements of the terahertz spectra of biomaterials and the ongoing efforts to create an all-solid-state technology suitable not only for improved scientific experiments but also for military and commercial applications. 相似文献
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《Radar, Sonar & Navigation, IET》2009,3(4):328-340
The authors present illumination waveforms matched to stochastic targets in the presence of signaldependent interference. The waveforms are formed by SNR and mutual information (MI) optimisation. We also use these waveforms in cognitive radar (CR) target identification application. In this application, the radar system attempts to identify a deterministic or random target using multiple transmissions. These transmissions are adaptively modified in response to previously received echoes. In addition, the authors present a new multi-band application of the CR platform. 相似文献