电化学法制备铁氰化铜/Nafion及其对卡托普利的检测

为对药片中卡托普利的含量进行精确测定,采用电聚合的方法,在玻碳电极表面沉积均匀分布的铁氰化铜/Nafion复合物。用扫描电镜(SEM)和X射线能量色散光谱(EDX)分别对样品的形貌和成分进行表征。利用循环伏安法(CV)研究药物分子卡托普利在该修饰电极上的电化学行为。研究结果显示,该修饰电极对卡托普利具有非常好的电催化性能。一定条件下,卡托普利在6.62×10-5~3.80×10-3mol/L范围内,其氧化峰电流与物质量浓度呈现很好的线性关系,其相关系数是0.996,检出限为5.0×10-6mol/L。该修饰电极具有快速、灵敏和高效的特点,并且可用于卡托普利实际样品的检测。     

壳聚糖-多壁碳纳米管/二茂铁修饰玻碳电极的电催化研究

利用多壁碳纳米管(MWCNTs)分散在壳聚糖/二茂铁形成的混合溶液,采用滴涂法对玻碳电极进行修饰,对多巴胺(DA)进行测定。结果表明,修饰后的玻碳电极能够有效促进DA在电极表面的电子传递速率,并且修饰电极对DA具有很好的催化氧化作用。DA氧化峰电流与其浓度在0.5～25μmol/L范围内呈良好的线性关系,检出限为3.89×10-7mol/L,并且常见物质对DA检测无干扰,DA注射液样品检测回收率为98.1%～100.9%。     

La_(0.7)Sr_(0.3)NiO_3/壳聚糖/聚吡咯/牛血红蛋白修饰玻碳电极的制备及构建过氧化氢传感器

在玻碳电极上修饰一层表面均匀的聚吡咯膜,然后利用钙钛矿和壳聚糖的复合膜来固定牛血红蛋白(Hb),制备出性能良好的过氧化氢生物传感器.采用循环伏安(CV)和扫描电镜对修饰电极进行了表征.该传感器对H2O2具有好的催化响应,且响应快.在优化的实验条件下,所制备的传感器对H2O2的线性范围为7.0×10-6～1.5×10-3mol/L,检测限为9.0×10-8mol/L.     

铁氰化铈/还原石墨烯纳米材料的制备及其对水合肼的电化学检测

通过电沉积的方法,在玻碳电极表面上沉积铁氰化铈/石墨烯(Ce HCF/RGO)纳米复合材料。用扫描电子显微镜(SEM)对其形貌进行表征,发现其粒径大小均一。用循环伏安法(CV)研究水合肼在不同电极的电化学行为。结果表明,与RGO修饰电极(RGO/GCE)和铁氰化铈修饰电极(Ce HCF/GCE)相比,铁氰化铈/石墨烯复合物修饰电极对水合肼具有更好的电催化氧化性能。在一定条件下,它对水合肼响应的线性范围为2.87×10~(-7)~8.56×10~(-4)mol/L,检出限为8.5×10~(-8)mol/L。可用于水合肼的电化学传感检测。     

电沉积制备铁氰化镍/Nafion纳米粒子及其对葡萄糖的电化学检测

采用电沉积的方法,在玻碳电极表面快速电沉积均匀分布的铁氰化镍/Naion纳米粒子。用X射线能量色散光谱图(EDX)和扫描电镜(SEM)对样品进行了表征,然后采用循环伏安法对该修饰电极进行电化学研究。结果表明:该电极对葡萄糖具有良好的电催化氧化性能,对葡萄糖响应的线性范围为1.560×10~(-6)~10.32×10~(-3)mol/L(R~2=0.999),检出限为1.2μmol/L(S/N=3)。制得的修饰电极对葡萄糖的电催化具有灵敏度高、重现性好和选择性强的优点。     

纳米TiO2/还原石墨烯复合修饰电极用于食品中 柠檬黄的检测

为了检测食品中柠檬黄的含量,利用滴涂法和电化学还原法制备纳米TiO_2/还原石墨烯复合修饰玻碳电极(TiO_2-Er GO/GCE)。采用透射电子显微镜和X射线粉末衍射仪对TiO_2和TiO_2-GO两种修饰电极材料进行表征;通过循环伏安法观察了柠檬黄在不同电极上的电化学行为,并对检测条件如p H值、富集电位、富集时间进行了优化。实验结果表明:TiO_2-Er GO/GCE增大了电极的电化学活性面积,提高了柠檬黄的电化学氧化响应;最优的检测条件为p H值为3.7、富集电位为-0.20 V、富集时间为180 s;在最优的检测条件下,采用线性扫描伏安法检测柠檬黄的线性范围为2.0×10-8~2.0×10-5 mol/L,检测限为8.0×10-9 mol/L(信噪比为3)。     

聚邻苯二胺负载纳米铜氧化物修饰玻碳电极的制备及表征

在磷酸盐缓冲溶液中于玻碳电极表面聚合邻苯二胺,再负载纳米铜氧化物,成功制备了邻苯二胺负载纳米铜氧化物修饰玻碳电极(CuO/P-oPD/GC).探讨了聚合和负载机理,用电化学交流阻抗谱表征了修饰电极界面的阻抗变化,用扫描电镜表征了聚邻苯二胺膜和负载铜氧化物后的表面形态,发现CuO/P-oPD/GC电极对H2O2有显著的电催化氧化、还原双重活性,并呈现"协同增敏"效应.考察了制备条件对CuO/P-oPD/GC电极电催化活性的影响,最佳CoO负载扫描次数为20,Cu2+的质量浓度为1.67mmol/L.对H2O2电催化氧化的线性方程为△ip8(μA)=0.08+5.64c(mmol/L)(R=0.9982),线性范围为2.4×10-2～48mmol/L,检测限为2.8×10-3mmol/L(3S/k);电催化还原的线性方程为△ipc(μA)=0.11-2.45c(mmol/L)(R=0.9820),线性范围为2.4×10-3～38.4mmol/L,检测限为2.0×10-4mmol/L(3S/k).该复合材料修饰电极的灵敏度高、稳定性好,用于实际水样中H2O2测定结果满意.     

一种基于静电纺碳纳米纤维的酚醛传感器

采用静电纺制备纳米纤维膜,接着通过高温碳化技术处理得到碳纳米纤维膜(ECNFs),再通过共混得到漆酶-全氟磺酸聚四氟乙烯共聚物-纳米碳纤维玻碳电极(laccase-Nafion-ECNFs/GCE)并制备新酚醛传感器。采用拉曼荧光显微分光计和Nicolet iS10傅里叶红外光谱仪对ECNFs进行分析;用循环伏安法对laccase-Nafion/GCE、laccase/GCE、laccase-Nafion-ECNFs/GCE进行了检测并测试扫描速率对laccase-Nafion-ECNFs/GCE效果的影响;采用方波伏安法对laccase-Nafion/GCE、laccase/GCE、laccase-Nafion-ECNFs/GCE进行了检测并测试对苯二酚浓度对laccase-Nafion-ECNFs/GCE效果的影响。结果表明:实验获得了ECNFs,且ECNFs的表面存在大量的羧基基团,有利于提高ECNFs的电催化性能和生物相容性;ECNFs的添加,提高了复合材料的导电率并增加了玻碳电极表面到漆酶中心的电子转移速率;漆酶在laccase-Nafion-ECNFs复合材料和玻碳电极表面很容易发生电子传输;ECNFs的修饰强烈地增加了玻碳电极对对苯二酚的电催化作用;该生物传感器的检测限为0.32μmol/L,线性范围为1~20μmol/L,可满足环境监测的要求。这种基于电纺纳米碳纤维的新型生物传感器装置具有很大的应用潜力。     

一种基于静电纺碳纳米纤维的酚醛传感器

采用静电纺制备纳米纤维膜,接着通过高温碳化技术处理得到碳纳米纤维膜(ECNFs),再通过共混得到漆酶-全氟磺酸聚四氟乙烯共聚物-纳米碳纤维玻碳电极(laccase-Nafion-ECNFs/GCE)并制备新酚醛传感器。采用拉曼荧光显微分光计和Nicolet iS10傅里叶红外光谱仪对ECNFs进行分析;用循环伏安法对laccase-Nafion/GCE、laccase/GCE、laccase-Nafion-ECNFs/GCE进行了检测并测试扫描速率对laccase-Nafion-ECNFs/GCE效果的影响;采用方波伏安法对laccase-Nafion/GCE、laccase/GCE、laccase-Nafion-ECNFs/GCE进行了检测并测试对苯二酚浓度对laccase-Nafion-ECNFs/GCE效果的影响。结果表明:实验获得了ECNFs,且ECNFs的表面存在大量的羧基基团,有利于提高ECNFs的电催化性能和生物相容性;ECNFs的添加,提高了复合材料的导电率并增加了玻碳电极表面到漆酶中心的电子转移速率;漆酶在laccase-Nafion-ECNFs复合材料和玻碳电极表面很容易发生电子传输;ECNFs的修饰强烈地增加了玻碳电极对对苯二酚的电催化作用;该生物传感器的检测限为0.32μmol/L,线性范围为1~20μmol/L,可满足环境监测的要求。这种基于电纺纳米碳纤维的新型生物传感器装置具有很大的应用潜力。     

基于[C_(10)-mim~+]Br~-固定HRP于Au/石墨烯复合材料电极表面的新型H_2O_2酶生物传感器

利用长链离子液体特殊的性质,用其固定HRP于Au/graphene电极表面(Nafion/HRP/[C10-mim+]Br-/Au/Gr/GCE)组装成H2O2传感器。用透射电镜来表征Au/氧化石墨烯的形貌,金纳米颗粒很均匀的分散在石墨烯表面,并不存在团聚现像。电化学技术检测Nafion/HRP/[C10-mim+]Br-/Au/Gr修饰电极对H2O2的响应情况,显示修饰电极对H2O2有很好的响应,在H2O2浓度2.0×10-6~1.2×10-3 mol/L的范围内,还原电流与浓度存在线性关系(R=0.997),检测限为3.0×10-7 mol/L;另外传感器具有很好的稳定性和选择性,为生物分子的检测提供新方法。     

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.