纳米/微米颗粒表面ζ-电势测量的验证试验

采用标准物质对ζ-电势测量的可行性加以评判。结果表明,ζ-电势的两种光学测量方法——电泳光散射法和显微镜法都有较好的重复性和准确性,对于标准样品,电泳光散射法测量重复性小于3%,测量误差小于4%;显微镜法测量重复性小于4%,测量误差小于7%。研究结果对该类仪器校准的标准物质研制和校准规范的制订具有积极的参考意义。     

总有机碳分析仪检定规程的适用性

以检定规程规定的标准物质与《中国药典》2010年版中规定的参考物质,对三种不同工作原理的总有机碳分析仪进行示值误差和重复性试验,由试验结果结合仪器工作原理分析了三种总有机碳分析仪检定规程的适用性,采用薄膜-电导检测技术的总有机碳分析仪不适用于JJG821-2005《总有机碳分析仪》;高温催化燃烧氧化法的仪器量程范围内低端部分也不一定能满足规程的技术要求。     

密闭体系下TATB的热分解动力学与热危害预测

为了解三氨基三硝基苯(TATB)在实际储存、运输过程中的热危险性,利用差示扫描量热仪(DSC)研究TATB在密闭体系下的热行为,并采用模型拟合方法建立TATB的热分解动力学模型。测试结果表明,其分解过程可以用两步平行反应进行描述,动力学模型表示为:第一步F→P1为N级反应,第二步F→P2为自催化反应。基于该模型对自加速分解温度(SADT)进行预测,结果表明,与包装材料相比,装载量对SADT的影响较大;对理想绝热条件下(即Φ=1)的分解过程进行预测,结果表明,起始温度为200℃的绝热诱导期接近450 h,且受热履历影响;对到达指定转化率所需时间(TCL)的预测表明,在100℃的等温环境下,TATB的分解转化率达到0.5%需要4 900 a左右。     

ICP-AES法测定超基性岩石中的主、次量元素

利用ICP-AES法对超基性岩石样品中主、次量元素的含量测定进行了研究,确定了样品的分解方法和仪器的最佳测试条件,方法的精密度、准确度高,通过标准样品验证,结果令人满意。     

带过氧键侧基的大分子过氧化物的热分解行为

用示差扫描量热法研究了1-(2-叔丁基过氧异丙基)-3-异丙烯基苯与苯乙烯、丙烯酸甲酯单体共聚后所得大分子过氧化物的热稳定性以及分解动力学。发现大分子过氧化物的热稳定性明显高于单体过氧化物，而且随共聚物中过氧基团含量的下降，大分子过氧化物的稳定性进一步提高。大分子过氧化物的等温分解呈一级反应，其分解速率常数与共聚物中过氧键含量以及分解温度有关。大分子过氧化物的分解活化能在110kJ／mol～115kJ／mol范围，低于相应D120单体过氧化物的139．2kJ／mol。     

高效液相色谱法测定绝缘油中糠醛含量的不确定度评定

绝缘油中的糠醛含量能够评估变压器绝缘纸的老化状况,并反映其绝缘性能.通过高效液相色谱法对绝缘油中糠醛含量进行定量分析,建立数学模型,确定测定结果的不确定度来源为糠醛标准物质、标准油液的配制、标准曲线的拟合、样品制备、回收率、测量重复性,并对测试结果进行不确定度评定.实验结果表明,绝缘油中糠醛样品浓度为1.05 mg/k...     

密闭消解HG-AFS法测定丹参植株中汞含量

为评价中江丹参植株汞含量水平、了解汞的植株分布,采用HNO_3-H_2O_2密闭消解、氢化物发生原子荧光法测定来自中江丹参种植基地的12个植株样品中的汞含量。实验优化还原反应条件,通过国家标准物质比较不同消解方法对测定结果的影响及验证方法的准确度和可靠性,密闭消解获得结果的准确度和精密度符合痕量分析要求。方法检出限为0.12μg/L,相对标准偏差为7.8%,样品加标回收率为81.0%~115.0%。丹参根中的汞含量未超过国家药典标准(0.2 mg/kg),部分茎和叶含量超标,植株汞含量分布为叶茎根。     

能谱仪在古陶瓷无损检测中的技术指标评估

为评估能谱仪对文物样品定量分析的准确性,尤其是针对元素成分复杂的古陶瓷样品,本研究采用与古陶瓷成分及其含量类似的岩石和土壤成分国家标准物质对仪器的稳定性、重复性和检出限3项技术指标进行了测试分析.结果 表明,所用能谱仪的稳定性和重复性较好,即使是个别元素由于其在所选用标准样品中的含量低或处于能谱仪检测范围边界的原因而造...     

GaAs中Si的二次离子质谱定量分析

评述砷化镓中硅SIMS定量分析的进展，讨论了相对灵敏度因子法。对此种GaAs的原始参考物质，用实验确认了其可靠性。为常规定量分析研制了二次参考物质。对一些关键实验因素，如样品装载、仪器参数以及离子选择等进行了仔细研究，并评价它们对定量重复性、精确性、检测限和基体效应的影响。Cs 源入射时GaAs中Si定量分析精度在15％内；检测AsSi二次离子时，29Si的检测限达5×1014atoms／cm3。     

环氧玻璃钢压力容器的疲劳性能分析

依据美国ASME标准的条件，对国内领先水平的玻璃钢压力容器的疲劳寿命进行了测试．从而对其疲劳性能进行了分析，补充了国内领先水平的玻璃钢压力容器性能评价内容．     

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.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.