微波消解-ICP-MS法测定土壤及耕作物小麦中的8种重金属元素

建立微波消解-电感耦合等离子体质谱(ICP-MS)法同时测定土壤及对应耕作物小麦中8种重金属元素(Cr、Ni、Cu、Zn、As、Cd、Hg、Pb)含量的方法,比较不同的酸消解体系对土壤消解效果的影响。通过优化仪器参数、选择103Rh作单一内标元素校正土壤基体的干扰及仪器信号漂移,并编辑校正方程消除质谱干扰等,实现对土壤、小麦籽粒及小麦粉中重金属元素的准确测定。结果表明:以HNO_3-H_2O_2-HF(5∶2∶2)为消解液体系微波消解土壤时,样品消解完全且效果最佳;各元素均呈现良好的线性关系,相关系数(r2)≥0.999 5;检出限在0.005～0.15μg/L之间。土壤标准物质GBW07454(GSS-25)和小麦标准物质GSB10046(GSB-24)的测定值与标准值吻合,加标回收率在93.4%～103.6%范围内,方法精密度和准确度高。实际样品结果显示,土壤中Cd、Pb达到3级中污染水平;对应小麦籽粒和小麦粉中重金属元素与土壤存在一定的同源性,重金属元素更易富集于小麦籽粒中,其中Cd污染最严重。     

微波消解在茶叶和土壤中营养元素分析的应用

采用微波消解法对茶叶和土壤样品进行处理,以ICP-AES测定了茶叶和土壤中十几种人体必需的营养元素,完善了微波消解技术的应用体系,回收率95.6%～104.3%,相对标准偏差为0.2%～7.5%,并与电热板消解法做了准确度、精密度、回收率比较.实验证明微波消解法精密度和稳定性更好,具有简便快速、污染少、试剂用量少等优点,能够完全满足土壤、茶叶中无机营养元素消解的要求.     

微波消解-电感耦合等离子体发射光谱仪法同时测定藏香中7种重金属元素

对藏香多种重金属元素同时检测的方法较少研究.本文建立了微波消解-电感耦合等离子发射光谱仪(ICP-OES)法同时测定藏香中7种重金属元素(As、Cd、Cr、Cu、Hg、Ni、Pb)的方法.藏香样品在HNO3溶液中120℃加热30 min后采用程序升温在100、120、150、185℃下进行微波消解,消解后的溶液经ICP...     

高压密闭消解ICP-AES法测土壤中的10种重金属元素

采用硝酸-氢氟酸高压密闭消解、硝酸复溶,用电感耦合等离子体原子发射法(ICP-AES)对土壤样品中10种重金属元素含量进行同时测定,通过对土壤标样的测定,并与ICP-MS法进行方法间比对,测定结果的误差在规范允许的误差范围之内。该法灵敏度高、消解完全、结果准确,是一种分析土壤中重金属元素含量的较好方法。     

土壤重金属消解方法的探索与研究

在土壤及矿渣的重金属含量测定过程中,对样品的消解是影响其含量测定结果是否准确的关键步骤,本文通过采用不同的消解方法来分别分析土壤及矿渣中重金属含量,对土壤及矿渣样品进行铅、镉、铬、锌、镍五种金属元素含量测定,结果表明,电热板消解法,微波消解法各有优点。     

微波消解-ICP-MS法测定木质包装材料中重金属元素

目的采用微波消解法处理木质包装材料,建立了电感耦合等离子体质谱法(ICP-MS)法测定木质包装材料中铬、钴、镍、铜、砷、硒、镉、锑、钡、汞、铊、铅等12种重金属元素的方法。方法样品用HNO3-H2O2混合酸进行微波消解,选择45Sc,72Ge,115In,209Bi等元素,作为内标校正基体干扰和信号漂移,采用八级杆碰撞/反应池技术消除质谱干扰,优化了仪器的工作条件。结果待测元素的标准曲线相关系数为0.9997~1.0000,方法检出限为0.01~0.28μg/L,加标回收率为89.4%~112.5%,相对标准偏差(RSD)为0.75%~3.81%。结论该方法快速简便、准确可靠,可用于测定木质包装材料中的重金属元素。     

微波消解-电感耦合等离子体质谱法同时测定土壤样品中八种重金属元素

本文以Ge、In、Re内标校正体系,采用微波消解-电感耦合等离子体质谱（ICP—MS）对土壤样品中砷、铅、铜、锌、镉、铬、汞、镍八种重金属元素进行同时测定,通过加标回收试验,建立了土壤样品中砷、铅、铜、锌、镉、铬、汞、镍八种重金属元素ICP—MS分析方法,各元素检出限均小于1．0ng／mL,测定8种元素的相对标准偏差均小于10％,各元素的加标回收率在86．3％～101．0％。实验表明：该法操作简单、快速,灵敏度高,重现性好,而且能够对八种重金属元素进行同时测定,大大提高了检测效率。     

不同前处理方法测定黄瓜中重金属镉

本文通过比较研究了湿式消解法、微波消解法、硫酸—过氧化氢快速消解发、盐酸浸提法等四种前处理方法测定黄瓜中镉含量。结果表明:利用湿式消解法和微波消解法作为前处理方法测定黄瓜中重金属镉的准确度和精密度较高。     

化妆品中锑检测方法研究

锑元素对人体存在一定的安全隐患,在化妆品生产过程中禁止添加的一类重金属。目前,锑金属的前处理方法主要分为湿法消解和微波消解两种,除此之外本文还简要介绍金属锑的法原子荧光光谱法、石墨炉原子吸收法、电感耦合等离子光谱法等检测方法。目的是为加强锑元素的化妆品监管及检测研究奠定基础。     

ICP-MS法检测中药材中7种重金属元素含量

目的:应用电感耦合等离子体质谱(ICP-MS)仪,建立辽五味子、人参、关龙胆、辽细辛、柴胡中铅(Pb)、镉(Cd)、铬(Cr)、砷(As)、硒(Se)、镍(Ni)、铜(Cu)7种重金属元素的测定方法。方法:样品经微波消解,以锗(72Ge)、铟(115In)、铋(209Bi)为内标,采用ICP-MS法同时测定上述7种元素的含量。结果:对于各测定元素,标准曲线的相关系数r≥0.9995,回收率为85.7%-96.2%,相对标准偏差为1.9%~6.5%。结论:该方法简便、快速、准确,可用于中药材中这7种重金属元素的含量测定。     

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.……     

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.……     

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.     

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 ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.     

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