共查询到20条相似文献,搜索用时 218 毫秒
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介绍了氯化钾电导率溶液标准物质的研制方法,采用与一级标准物质比较定值的方法对该标准物质进行了定值,利用高精度电导率仪对定值结果进行了验证,同时对该标准物质进行了均匀性检验和稳定性考察。氯化钾电导率溶液标准物质的定值结果为1408μS/cm,扩展不确定度为:Urel=0.6%,k=2。其均匀性和稳定性检验结果表明,该标准物质符合国家二级标准物质的技术要求。 相似文献
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苯系物溶液标准物质的研究 总被引:2,自引:0,他引:2
论述了苯系物溶液标准物质的研究工作 ,系统地介绍了标准物质原材料的选择、特性量值的测量方法、标准物质的制备方法、均匀性检验、稳定性考察以及定值测量。对样品的均匀性、测量的分散性及其他因素引入的不确定度分量分析和确定后 ,给出了整个测量过程不确定度的合成结果。对气相色谱法和液相色谱法所得到的实验结果进行了统计分析 ,其均匀性符合F检验和T检验 ,满足标准物质的技术规范。对苯系物溶液标准物质的稳定性进行了 2年的考察 ,证明该标准物质是稳定的 ,浓度值的不确定度为 2 8%。苯系物溶液标准物质已被批准为国家一级标准物质 相似文献
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文章以氟化钠标准物质为原料,超纯水为溶剂,采用重量-容量法制备水中氟离子溶液标准物质,介绍了水中氟离子溶液标准物质的研制方法。研制的水中氟离子溶液标准物质利用离子色谱法进行检测,分别采用F检验和回归曲线法进行均匀性和稳定性检验,方差分析和线性拟合结果表明该标准物质具有良好的均匀性和稳定性。选择国家二级标准物质采用同样的检测方法进行验证,结果表明制备的标准物质的方法准确度满足要求。研制的水中氟离子溶液标准物质的定值结果为1 000 mg/L,相对扩展不确定度Urel=1%(k=2)。该标准物质量值准确,且具有溯源性,可用于水中氟离子测量过程的质量控制及分析方法的确认和评价。 相似文献
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《计量技术》2021,(6)
本课题研制了乙腈中展青霉素的溶液标准物质1种,并已成功申报为国家二级标准物质(GBW(E)100674)。该溶液标准物质以展青霉素纯度国家二级标准物质(GBW(E)100673)为原料,采用重量容量法配制。依据JJF1343-2012《标准物质定值的通用原则及统计学原理》的要求,本研究采用液相色谱法对乙腈中展青霉素溶液标准物质进行均匀性、短期稳定性和长期稳定性的评价。定值不确定度包含原料纯度、溶液配制、均匀性、短期稳定性和长期稳定性五个方面引入的不确定度。最终,该溶液标准物质GBW(E)100674的定值结果为100μg/m L,不确定度为2%。本研究研制展青霉素溶液标准物质的量值具有溯源性和准确性,可以支持国家食品安全检测的需要。 相似文献
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《计量技术》2021,(7)
研制了液相色谱-质谱联用仪(LC-MS)校准用甲醇水中咖啡因溶液标准物质并进行不确定度评定。以咖啡因纯品、色谱级甲醇和实验室一级用水为原材料,利用质量平衡法对咖啡因纯品进行纯度核验,利用基准方法重量—容量法配制浓度9.94 mg/L甲醇水中咖啡因溶液标准物质。采用液相色谱法对9.94 mg/L甲醇水中咖啡因标准溶液和国家二级标准物质GBW(E)130453进行量值比对,并对溶液标准物质的均匀性、短期稳定性和长期稳定性进行考察。结果表明研制的9.94 mg/L的甲醇水中咖啡因溶液标准物质的均匀性和稳定性良好,相对扩展不确定度为2%(k=2),有效期为12个月。 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