氮中微量氧气体标准物质分析方法和定值方法的研究 (上)

介绍了氮中微量氧标准气体的分析方法,给出了分析条件和方法的精密度,并对该标准气体配制的均匀性、稳定性的实验结果进行了分析与考察,对该气体标准物质的性能进行了评价。氧含量在(2~10)μmol/mol浓度范围气体标准物质定值不确定度<±2%;氧含量在(20~100)μmol/mol浓度范围气体标准物质定值不确定度<±1%,取得了国际的等效性。     

称量法制备1μmol/mol氮中微量氧气体标准物质的质量控制

依据ISO 6142和GB/T 5274标准,采用称量法制备1 μmol/mol的氮中微量氧气体标准物质.使用钢瓶清洗系统和配气系统,通过超纯气体纯化器对高纯氮中的氧杂质进行脱除,使纯化后氧含量小于3 nmol/mol.同时平行配制模拟气,确保空气中的氧对所制备的标准物质污染最小.用微量氧分析仪考察标准物质随贮存时间和压力变化的稳定性,并通过比对验证了标准物质的定值结果和不确定度,证明了该制备方法可行,定值准确可靠.气体标准物质定值扩展不确定度为2%,有效期限为12个月.     

氮(空气)中二氧化硫气体标准物质的研制

采用称量法制备了氮(空气)中二氧化硫气体标准物质,采用化学法进行均匀性、稳定性考察并进行了比对分析。结果表明用称量法制备的浓度范围为1×10-6~10×10-2(mol/mol)的氮(空气)中二氧化硫气体标准物质其均匀性良好,稳定性可靠,符合气体标准物质制备的要求。该气体标准物质相对扩展不确定度为2%。     

氮(空气)中氢气体标准物质的研制

采用称量法制备了氮(空气)中氢气体标准物质,采用气相色谱法进行了均匀性、稳定性考察并进行了比对分析。结果表明用称量法制备的浓度范围为10×10-6~98×10-2(mol/mol)的氮(空气)中氢气体标准物质均匀性良好,稳定性可靠,符合气体标准物质制备的要求。该气体标准物质相对扩展不确定度为2%。     

六氟化硫中六氟乙烷气体标准物质的研制

采用称量法制备并计算定值,研制(10~100)×10-6(mol/mol)六氟化硫中六氟乙烷气体标准物质。采用自主研制的钢瓶自动清洗系统、配气系统和优化的配气工艺流程保证了研制水平。对气体标准物质进行了制备方法的研究、均匀性与稳定性检验试验,结果表明研制的气体标准物质定值的扩展不确定度优于1.5%(k=2),符合气体标准物质制备要求。     

红外测油仪用标准物质的研制

为保证分析测量结果的准确可靠,研制了浓度为1000μg/mL的红外测油仪用溶液标准物质。以称量-容量法制备,计算结果定值,对原料进行了纯度分析、制备方法控制,考察了样品均匀性和稳定性,评定了所配制标准物质浓度定值的不确定度。通过与GBW(E)130171比对,验证了标准物质的定值结果准确可靠,相对扩展不确定度<2%(k=2),有效期限为12个月。该标准物质已被批准为国家二级标准物质。     

甲烷中硫化氢气体标准物质的研制

以高纯硫化氢和高纯甲烷为原料,采用称重法制备甲烷中硫化氢气体标准物质。采用气相色谱法(FPD)进行均匀性、稳定性考察。结果表明用称量法制备的浓度为10μmol/mol的甲烷中硫化氢气体标准物质均匀性良好,稳定性可靠,符合气体标准物质制备的要求。该气体标准物质相对扩展不确定度Urel=2%,k=2。     

瓶装氮气中22组分挥发性卤代烃混合气体标准物质的研制

介绍瓶装1μmol/mol氮气中22组分挥发性卤代烃混合气体标准物质的研制过程。以22种挥发性卤代烃高纯试剂为原料,采用称量法制备并计算定值,评定制备过程引入的不确定度、以及均匀性和稳定性引入的不确定度,并将研制的标准物质送至中国计量科学研究院进行测试比对,采用En值评定比对结果,结果显示En值均1,所有组分比对结果判定均为满意,验证研制标物定值结果的准确性。该气体标准物质获得国家二级气体标准物质证书,编号为GBW(E)062232,其定值的相对扩展不确定度为U=5.0%(k=2),有效期限为12个月。     

氦中氖气体标准物质的研制

开展了氦中氖气体标准物质的制备技术研究,并进行了均匀性、稳定性考察及不确定度评定。结果表明研制的气体标准物质量值准确可靠,达到了国家二级气体标准物质的要求。氦中氖浓度为0.05%~20%(mol/mol),扩展不确定度为1.5%(k=2)。     

氮中甲硫醇、甲硫醚、二甲基二硫醚混合气体标准物质的研制

该文介绍瓶装1.00～20.0μmol/mol氮中3组分有机硫化合物混合气体标准物质的研制方法。以甲硫醇、甲硫醚、二甲基二硫醚等高纯气体和试剂为原料,进行纯度分析后,采用称量法制备定值,并使用气相色谱硫化学发光检测器对其均匀性和稳定性进行检验。实验结果表明,该标准物质的均匀性和稳定性满足F检验和t检验的要求,其定值的相对扩展不确定度为U=2.0%(k=2),有效期为12个月。该标准物质获得国家二级气体标准物质证书,编号为GBW(E)062461。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

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.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

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.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

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.……     

Optimum-Simulation von Ernteprozessen

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

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 ...