基于P&T-GC/MS指纹图谱评价丝束加香滤棒质量的稳定性

目的 形成丝束加香滤棒质量稳定性的评价体系。方法 实验采用吹扫捕集-气相色谱-质谱技术（Purge&Trap-Gas Chromatography-Mass Spectrometry,P&T-GC-MS）结合“中药色谱指纹图谱相似度评价系统”对丝束加香滤棒中特征香味成分进行分析,以建立P&T-GC-MS指纹图谱,并利用欧氏距离法计算其相似度,以及聚类分析法评价不同批次间样品的差异性。结果 相同浓度、不同批次丝束加香滤棒的相似度均高于0.920,表明批次间、批次内样品的质量稳定性较好;各特征香味成分峰面积、保留时间的RSD值均小于1.70%,表明该方法具有良好的精密度、稳定性和重现性;所建的丝束加香滤棒标准指纹图谱与聚类分析结果一致,可将不同浓度的丝束加香滤棒进行有效甄别。结论 该方法可为评价丝束加香滤棒的质量稳定性提供参考依据。     

吹扫捕集-气相色谱法测定水中苯系物

吹扫捕集技术富集水中的苯系物可省去繁琐的溶剂萃取步骤,提高样品加标回收率。用吹扫捕集-气相色谱法测定水中7种苯系物,当水样进样体积为5mL时,方法检出限为0.5～2.1ug/L,用该方法对实际水样中的7种苯系物进行测定,回收率为95.0%～105.8%,测定结果的相对偏差均小于4%。     

吹扫捕集气质联用法快速测定化工污泥中的12种挥发性有机物

该研究建立吹扫捕集气质联用法快速测定化工污泥中12种挥发性有机物的分析方法,采用吹扫捕集进样,DB-624色谱柱分离,质谱检测器进行检测,对吹扫时间、吹扫温度、脱附时间和脱附温度四个因素进行优化,考察基质效应和盐效应的影响,同时对检出限、加标回收率和精密度进行实验。结果表明,在0.002～0.100 mg/L范围内线性良好,相关系数(r²)>0.991,方法检出限为0.2～0.8μg/L,相对标准偏差(n=6)为0.50%～7.1%,回收率为90.8%～121%。该方法能满足GB 5085.3限值的要求,适用于化工污泥中12种挥发性有机物的快速定性、定量分析。     

吹扫捕集气质联用法检测包装纸挥发性有机物的迁移量

本文建立了包装纸中6种典型挥发性有机物测定的吹扫捕集气质联用法,并对样品加热温度、吹扫时间、解吸时间进行了优化。该方法操作简便、灵敏度高,检出限为0.0015μg/mL～0.1300μg/mL;相关系数(R~2)大于0.997;平均回收率为87.83%～139.13%,RSD在0.33%～11.55%之间。方法适用于包装纸中挥发性有机物的迁移量检测,有望为包装纸的安全绿色印刷提供技术支撑。     

ICP-MS法同时测定卷烟主流烟气中的7种痕量元素

建立卷烟主流烟气中7种有害痕量元素的测定方法。采用剑桥滤片和吸收瓶分别捕集卷烟主流烟气中粒相物和气相物中的As、Cd、Cr、Pb、Ni、Se、Hg元素,硝酸-过氧化氢混合溶液微波消解后,用电感耦合等离子体质谱(ICPMS)法同时测定捕集到的7种元素。方法相对标准偏差15%(n=6),检出限为0.12~2.3 ng/支,回收率为82%~110%。     

针对有机挥发份提取样品的两种定量分析方法比对研究

通过转相-吹扫捕集(PT)-气质联机法(A法)及液体直接进样法(B法)两种测试手段,对有机挥发份(苯系物及氯苯类化合物)溶液进行定量分析,两种分析方法的RSD为0.81-5.12%;直接进样分析快速、稳定,而吹扫捕集-GCMS灵敏度高,检出限可达0.3-0.3ug/L,说明两种分析方法可互为佐证,可以满足苯系物和氯苯类有机提取溶液的定量分析要求。     

探讨吹扫捕集气相色谱法测定饮用水中苯系物

吹扫捕集气相色谱法测定饮用水中的苯系物无需进行萃取等繁琐的样品前处理,操作简单灵敏。本文在设定的色谱和吹扫条件下,苯系物各组分线性方程的相关系数均大于0.9990,方法检出限在0.10～0.21μg·L-1,加标回收率在97～102%之间,适用于饮用水低浓度挥发性苯系物的测定。     

吹扫捕集/气质联用法测定水中三氯乙醛

本研究利用了三氯乙醛在碱性条件下定量转化为三氯甲烷的特性,开发了通过吹扫捕集/气质联用测定三氯甲烷间接测定三氯乙醛的检测方法,并对方法的检出限、精密度、加标回收率等方面进行了论述。     

吹扫捕集与气相色谱—质谱联用测定水中挥发性卤代烃

研究建立了吹扫捕集/气相色谱/质谱法测定水中挥发性卤代烃的分析方法,并利用该方法对不同水体中的该类物质进行了测定。11种挥发性卤代烃的最低检出限在0.08～0.33μg/L之间,水样的加标回收率为90％～105％,10μg/L的挥发性卤代烃标准溶液经6次重复测定后其相对标准偏差小于4％。     

全自动吹扫捕集-气相色谱质谱联用仪测定饮用水源水中特定挥发性有机物的研究

将全自动吹扫捕集用于水中挥发性有机物的前处理,结合气相色谱质谱联用仪的优化条件,可达到25组分挥发性有机物的有效分离、定性和定量分析。在全扫描模式下,13组分挥发性有机物在2.5-25μg/L的范围内,工作曲线相关系数均大于0.990,检出限为0.5-1.7μg/L、测定下限为2.0-6.8μg/L;精密度RSD值范围为3.4%-11.6%;加标回收率范围为95.4%-114.1%,可实现水中挥发有机物大量样品的快速、高效、准确测定。     

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.……     

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...     

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.     

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.……     

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.     

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.     

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.     

Brainstorming for ISO Strategy 2016-2020

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