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光声光谱作为一种比较新型的材料无损测试技术,具有灵敏度高、能进行微量分析、以及不受样品形状限制等优点。本文对光声光谱测试技术的测试原理及测试系统组成进行了详细说明,并举例说明其在材料分析中的应用。 相似文献
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光声光谱作为一种比较新型的材料无损测试技术,具有灵敏度高,能进行微量分析,以及不受样品形状限制等优点。本文对光声光谱测试技术的测试原理及测试系统组成进行了详细说明,并举例说明其在材料分析中的应用。 相似文献
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水声材料声性能自由场测量技术研究 总被引:6,自引:0,他引:6
本文提出了一种新的大面积水声无源材料声学性能测量技术,可以在小型消声水池中测量大面积材料的某些声学性能随频率变化规律。材料样品的典型尺寸为1000 m m ×1000 m m 左右,目前的测量频率范围为2 .5 ~20k Hz,测量参数包括反射系数( 回声降低) ,透射系数( 插入损失) 等。对标准样品进行了性能测量,测量结果和平面波理论模型计算值有较好的吻合,表明该技术有很好的发展潜力 相似文献
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据媒体报导,不久前,德国马普铁材料研究所应用高分辨率光栅电子显微镜和原子显微镜,在世界上首次拍摄出纳米材料的三维立体结构。上述两种显微镜在科研中通常是独立使用,而该所创新地将两种仪器结合起来,使其具有前所未有的探测纳米材料立体结构的功能。这种3D技术还可用来探测高强度钢和生物材料,并具有其他显微工艺无法提供的功能。另外,电子显微镜3D工艺拍摄的材料样品可以是片状的,但摄取的信息以立体断层图像的方式显示。这样,研究人员便可对材料进行层层分析,得出完整的数字立体图像。这套集成的显微镜系统操作起来完全是自动化的,因此可对较大的固体材料试样,如对体积为70立方毫米的试样进行分析。 相似文献
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当前,化学检测样品前处理技术发展快速,通过不断研究与开发,其新技术发展及应用广泛,本文分析了当前化学检测样品前处理技术的发展现状,将常用的固体样品前处理技术与液体样品前处理技术进行对比、分析,针对几种常用的样品前处理技术及其研究进展进行深入分析,具有一定的借鉴价值。 相似文献
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较详细地阐明了电子背散射衍射技术(EBSD)的基本原理、实验分析方法。通过安装在场发射扫描电子显微镜上的电子背散射衍射系统,可以对块状样品进行材料微区范围内取向与结构的快速分析,使显微组织、微区成分与结晶学数据分析联系起来,电子背散射衍射技术成为现代材料科学研究的重要实验技术。 相似文献
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《International journal for numerical methods in engineering》2018,113(9):1488-1506
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method. 相似文献
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Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
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A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa. 相似文献
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On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.…… 相似文献
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Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß. 相似文献
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C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill. 相似文献
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Dimiter Hadjistamov 《材料科学与工程:中英文B版...》2019,(2):56-65
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ... 相似文献
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《中国标准化(英文版)》2014,(4)
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from 相似文献
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《中国标准化(英文版)》2014,(5)
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively. 相似文献