多溴联苯醚降解的代谢途径

添加型阻燃剂多溴联苯醚(PBDEs)由于具有优异的阻燃性能,已被广泛应用于各种消费品中。PBDEs具有低水溶性,会强烈吸附有机物,导致PBDEs在环境介质和食物链中大量富积,对人类和动物都造成巨大危害。对多溴联苯醚生物降解、光降解和零价铁降解过程中的代谢途径和代谢过程中所需的酶进行综述,为多溴联苯醚的修复提供理论基础。     

气相色谱-质谱联用法测定印制线路板中多溴联苯及多溴联苯醚的不确定度评估

分析了气相色谱-质谱联用法测定印制线路板中多溴联苯(PBBs)及多溴联苯醚(PBDEs)含量的不确定度来源,求出各不确定度分量,将不确定度分量合成给出实验结果不确定度。     

厦门港和筼筜湖沉积物中多溴联苯醚类防火剂(PBDEs)的色谱一质谱联机同位素稀释法测定

利用13C标记的多溴联苯醚标准作内标对厦门沿岸海域和筼筜湖沉积物进行色谱—质谱联机测定并采用同位素稀释法进行数据收集和计算,分别测定PBDE3、15、28、47、60、85、99、100、138、153、154和183共12个同类化合物,其回收率范围为75.8-100.5%,最低检测限0.02ng/g(d),沉积物中总PBDE最高值为厦门第一码头2.06ng/g(d),最低是厦门大学海水浴场为0.10ng/g(d)。     

厦门港和筼筜湖沉积物中多溴联苯醚类防火剂(PBDEs)的色谱-质谱联机同位素稀释法测定

利用^13C标记的多溴联苯醚标准作内标对厦门沿岸海域和筼筜湖沉积物进行色谱-质谱联机测定并采用同位索稀释法进行数据收集和计算,分别测定PBDE3、15、28、47、60、85、99、100、138、153、154和183共12个同类化合物,其回收率范围为75．8—100．5％,最低检测限0．02ng／g（d）,沉积物中总PBDE最高值为厦门第一码头2．06ng／g（d）,最低是厦门大学海水浴场为0．10ng／g（d）。     

超声萃取-气相色谱质谱法测定环境和食品中多溴联苯及多溴联苯醚

建立了同时测定环境和食品中10种多溴联苯(PBBs)和多溴联苯醚(PBDEs)的超声萃取-气相色谱质谱方法。在最佳的萃取条件下,该方法的检出限和相对标准偏差s分别为0.97~5.8ng/g和6.3~13.0%,各物质的线性范围达3个数量级,相关系数不低于0.9987。将该方法应用于环境和食品中多溴联苯和多溴联苯醚的分析,均没有检测到目标分析物,各目标分析物的加标回收率为71.5~113.7%,相对标准偏差s)为6.1~13.3%。与索氏提取相比,方法操作简单,快捷,适用于环境和食品中多溴联苯(PBBs)和多溴联苯醚(PBDEs)的测定。     

ROHS指令中多溴联苯、多溴联苯醚的前处理研究

本文介绍了ROHS指令中多溴联苯、多溴联苯醚的前处理技术发展现状与趋势.     

化学计量,RoHS检测中的重要支柱

一、“健康、安全与环境”引发“RoHS指令” 当前，随着科技的发展、人们物质生活水平的不断提高，世界各国均面临严重的“电子垃圾问题”，特别突出的就是在电视机、电脑、手机、音响等电子产品中含有铅、镉、汞、六价铬、溴化阻燃剂等大量有毒有害物质。如电视机或电脑显示器中的阴极射线管中含有大量的铅，PVC电缆包皮中也含有以热稳定剂形式加入的铅，这些铅一旦进入土壤会严重污染水源，危害植物和微生物，最终通过生物圈的循环危害人类健康，尤其会对儿童的大脑发育造成极大的危害：在机电产品所广泛使用的塑料材料中，添加了大量多溴联苯（PBB）、多溴联苯醚（PBDE）等阻燃物质，而PBB和PBDE属于生物积累性化学品，能够阻碍新陈代谢、引起内分泌紊乱、损害神经系统、导致消化系统和淋巴系统癌症等。“电子垃圾”处理不当危害极其严重，这些物质进入环境，会产生持续污染，所造成的恶果在相当长的时期内难以消除。     

GC-MS测定电子电气产品中限用阻燃剂的不确定度评定

本文按照《GB/T 26125-2011电子电气产品六种限用物质(铅、汞、镉、六价铬、多溴联苯和多溴二苯醚)的测定》对测定电子电气中限用阻燃剂--多溴联苯、多溴二苯醚含量的不确定度进行了评定,分析和量化了影响测定结果的不确定度分量,将不确定度分量合成,得到了20种限用阻燃剂中日常检出频率较高的十溴联苯、八溴二苯醚和十溴二苯醚含量的扩展不确定度分别为0.9764mg/kg、1.237mg/kg和2.306mg/kg。     

气相色谱-质谱法测定家居产品中多溴联苯和多溴联苯醚

提出气相质谱法测定家居产品中多溴联苯和多溴联苯醚的检测方法。纺织品以甲苯为溶剂,在温度为30℃、功率为600w、提取时间为30min的条件下,提取效果最佳;塑料制品以正己烷-二氯甲苯(1:2)为溶剂,在温度30℃、功率600w、提取时间为20min的条件下,提取效率最高。实验选取DB-5HT超高温色谱柱,以恒温和程序升温相结合,完成了20种多溴联苯和多溴联苯醚的分离与测定。方法经优化后多溴联苯和多溴联苯醚的回收率为85.2%～105.8%,精度为3.6%～8.9%(n=10)。从30件家具产品中检测到8种产品含有溴系阻燃剂,含量从0.86 ～ 1716.98 mg/kg不等,主要存在于断路器、插座和沙发纺织面料中。     

我国电子电气产品污染控制标准化现状

<正>在当今信息技术时代,电子信息技术产品给我们社会方方面面带来极大便利,但其产品中含有铅、镉、汞和六价铬等重金属以及多溴联苯、多溴二苯醚和四溴双酚A等有毒有害物质,会对人体和环境造成不利影     

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.     

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...     

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.     

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.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.