美国麦乐鸡被指含泥胶成分

<正>专家:添加剂有致癌性,食用不宜过量近日,美国麦当劳销售的麦乐鸡被检出含化学成分"聚二甲基硅氧烷"和"特丁基对苯二酚",引发人们对食品安全的担忧。麦当劳中国有限公司日前回应:这两种物质的含量符合现行     

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<正>信息化、低碳和资源高效利用是当代社会的几大主题词,而电化学储能器件是构建信息社会、低碳社会的重要工具。过去二十余年中,锂离子电池的发展大大丰富了电化学储能器件的内涵和外延,使智能手机和电动汽车的发展成为可能;而近年来更高容量新型锂二次电池(如:锂硫、锂空电池等)的出现和发展则为未来信息高速公路、低碳社会的建设保驾护航。大容量、高效率、长寿命是电化学储能器件发展的终极目标。对于锂二次电池及其它电化学储能器件,碳基材料具有其优异电输运特性和高活性表面,既是重要的活性电极材料,又是     

具有AIE特性的咔唑衍生物的合成及光谱和电化学性能

以咔唑、芴酮等为原料,通过亲核加成等反应合成了两个新型咔唑衍生物:3-亚芴基肼撑亚甲基-N-乙基咔唑和3,6-双(亚芴基肼撑亚甲基)-N-乙基咔唑(a和b)。通过红外、核磁和元素分析对所合成的两种化合物的结构进行了表征,并考察了其紫外吸收光谱、荧光光谱、电化学行为和热稳定性。实验结果表明:所合成化合物a和b的薄膜均显示出较强的红色荧光,且均具有明显的聚集诱导发光(Aggregation-Induced Emission,AIE)特性;化合物a和b的电离势分别为5.62和5.65eV,与正电极ITO的功函数相匹配,可有效降低空穴注入的能垒,有利于空穴的传输;化合物a和b的热分解温度分别是310℃和309℃,均具有良好的热稳定性。     

国家卫计委对三类新食品添加剂的使用发布解读

<正>近期,国家卫生计生委发布公告称,根据《食品安全法》规定,审评机构组织专家对食品添加剂新品种氨基乙酸(羟基乙腈法)、食品用香料新品种乙基芳樟基醚和食品添加剂β-胡萝卜素扩大使用范围的安全性评估材料审查并通过。这三类食品添加剂作用于食品,将有助于改善食品的味道和色泽,在国外有较长的使用历史。随后,国家卫生计生委就该公告中涉及新增三种食品添加剂新品种扩大使用范围发布相关解读,对其使用背景、工艺必要性作了全面介绍。     

接枝己基噻吩共轭分子的电化学聚合和性能表征

利用斯蒂尔偶联反应合成了一种基于苯并硒二唑和己基噻吩的有机共轭单体,通过电化学方法制备导电聚合物,并对其进行了结构表征和电化学性能测试。核磁共振1H谱和13C谱验证单体与理论结构一致,红外结果验证了电化学聚合位点为己基噻吩的α位;循环伏安测试表明聚合物具有良好的电化学活性和稳定性,经过100圈循环扫描后电化学活性仍保持92.3%;光滑、均质连续的表面形貌有利于提高聚合物的电导率和电子传输性能、较高的热稳定性表明其能够应用在光电器件中;在0 V到1.2 V电压范围内,光谱电化学测试中聚合物薄膜颜色从淡蓝色到灰色的转变说明聚合物具有良好的电致变色特性;以上结论表明聚合物在电致变色材料中具有应用前景。     

取代基对光致变色不对称二芳烯电化学开关性能的影响

合成了一系列具有不同取代基团的二芳烯化合物,研究了取代基对其电化学开关性能的影响.结果表明:化合物上不同取代基影响其电化学开关性能,与闭环态中取代基苯基上的电子向中心环转移的结果有关;取代基的吸电子性与供电子性对起始氧化电位作用显著,除乙氧基外,氯、氟、甲基、甲氧基在开环和闭环态中对起始氧化电位有较大影响.     

锂离子电池三维石墨烯基复合负极材料的研究进展

石墨烯具有优异的电学和力学性能以及高比表面积等特点,石墨烯基复合材料在电化学能源中的应用备受关注。构筑三维结构石墨烯基复合材料可以有效提高石墨烯材料的电化学性能。主要介绍了近年来国内外三维石墨烯基复合材料的制备方法及其在锂离子电池负极中的应用,并对其进一步的发展和应用予以展望。     

高比表面积活性炭基水系Na_2SO_4电化学电容器的制备

以石油焦为前驱体和KOH作为活化剂制备一种用于电化学电容器的高比表面积活性炭,采用廉价弱腐蚀性的Na_2SO_4电解液制备一种高电压的对称活性炭基水系电化学电容器,用N2吸附-脱附仪表征活性炭电极材料的孔结构参数,用循环伏安、恒流充放电和交流阻抗等电化学测试方法研究其电化学性能。研究结果表明,活性炭的比表面积为2855m~2/g,平均孔径为2.31nm;活性炭基水系电化学电容器在1.0mol/L Na_2SO_4电解液中扫描速率为2mV/s的比电容能达到188F/g,在功率密度为200W/kg时能量密度达到19.4Wh/kg,活性炭基水系电化学电容器在电压值为1.6V下展现了良好的循环性能,意味着Na_2SO_4电解液对开发能量密度高和环境友好的电化学电容器有着重要的意义。     

重点实验室研究进展

正武汉理工大学—哈佛大学纳米联合重点实验室在石墨烯构筑与应用方向取得新进展石墨烯由于高电导率、高柔韧性、表面官能团丰富而广泛应用于修饰电化学储能材料。然而在合成过程中,石墨烯易发生自团聚,限制了其电化学性能的进一步提高。如何提高石墨烯利用效率,将其有序化,一直是石墨烯基储能材料,乃至石墨烯应用领域     

纳米技术引领绿色印刷制造

<正>印刷技术为人类文明的传承和信息的传播作出了不可磨灭的贡献,但近年来,传统印刷业也面临着环境保护、电子出版等多方面的压力与挑战。传统印刷产业链主要包括3大关键污染环节:曝光冲洗制版、电化学氧化制备铝版基和使用有害溶剂生产油墨。因此",发展绿色印刷技术,实施绿色印刷战略"成为印刷产业生存和发展的迫切需求。中国科学院化学研究所(简称"中科院化学所")绿色印刷重点实验室基于纳米材料     

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.     

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.     

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.     

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.     

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.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.