机动车尾气的道边在线实时监测(下)

利用调谐二极管激光器吸收光谱和紫外差分吸收光谱原理研制了道边实时监测机动车尾气仪,详细讨论了该仪器对几种主要有害气体如CO,CO2,NOx和HC（分别用NO和丁二烯代表）的测试及校正原理．以及各种环境因素对测试结果的影响．全文分上、下两部分．本部分（下）介绍了该仪器的主要技术难点、创新点和性能参数,报道了用该仪器跟美国MD-LaserTech公司商业化产品在北京测试现场的部分路边测试实验结果,讨论了各种环境因素如天气、车型、季节、车速、路况等对测试结果的影响及校正．对仪器的性能参数跟国外同类仪器比较发现,我们研制的仪器性能略优于国外同类仪器90年代后期水平．本技术拥有完整自主知识产权,填补了国内空白．     

差分吸收光谱法在线测量排放烟气浓度研究

介绍了差分吸收光谱(DOAS)在线测量系统,分析了DOAS的光谱处理方法.研究了SO2气体浓度的DOAS测量方法,可以实现排放烟气中SO2的在线测量.DOAS法利用数学方法将吸收光谱分解成快变和慢变部分,他利用快变部分计算气体成分的浓度,这使得烟尘干扰和光源强度变化不影响烟气浓度测量精度.DOAS法用线测量代替点测量,可获得区域内更具有代表性的数据,能更准确的反映烟气排放情况;可同时对多种污染物的进行定性、定量分析;是非接触性测量,无需采样.     

基于可调谐二极管激光吸收光谱技术在线监测机动车尾气排放CO和CO2的方法

基于可调谐二极管激光吸收光谱学(TDLAS)技术的原理,在分析了在线监测机动车尾气排放的污染气体浓度的特殊性的基础上,研究了烟羽的影响以及在线监测中浓度反演的方法,研制了TDLAS实验系统,用该系统对北京市学院路监测点和大羊坊高速公路收费站监测点进行了机动车尾气CO和CO2的实时在线监测,并对监测数据进行了统计和分析.实验表明,TDLAS技术具有灵敏度高、选择性好、响应速度快等特点,适合于机动车尾气排放CO和CO2的在线监测.     

基于多方法集成的烟气、烟尘排放监测系统

根据SO2和NOx以及烟尘分别在不同光谱波段具有吸收和散射特性的特点,对同一测量光谱分别用差分吸收光谱法(DOAS)和多波长消光法进行数据处理,并辅之互相关法,可同时监测SO2、NOx和烟尘的浓度、烟尘粒度以及总排放量。基于这些方法,研制了一套直接在线烟气连续监测系统(CEMS)。在一采暖锅炉上成功地进行了不同运行工况下现场较长时间连续监测。     

基于抽象工厂模式的机载总线数据通用化处理方法研究

为解决目前TDLAS波长扫描直接吸收法测温领域存在的干扰吸收峰影响温度测量准确性的问题,提出了一种基于吸收光谱线型对称的积分吸光度计算方法,利用中心频率至无干扰吸收峰一侧频率范围的吸光度,根据对称性得到全频域的积分吸光度,以此来排除干扰吸收峰的影响,提高温度测量准确性。选取7185.6 cm^-1和7444.4 cm^-1两条H₂O吸收谱线,利用吸收光谱仿真数据在400~2600 K温度范围内选择8个温度点进行温度仿真计算,同时在实验室环境下搭建一套TDLAS测量系统,在573~1173 K温度范围内进行了管炉测温实验,并将吸收光谱线型对称积分吸光度计算法的测量结果与忽略干扰峰影响的单峰法的测量结果进行对比,结果显示：二者仿真计算温度的平均相对误差分别为1.11%和5.66%,实验测量温度的平均相对误差分别为1.02%和9%,验证了存在干扰吸收峰时根据线型对称性获取积分吸光度进行温度测量的可行性与准确性,为推动TDLAS温度测量技术发展提供了重要借鉴。     

烟气排放污染物(SO2)在线监测系统

紫外 可见差分吸收光谱法 (DOAS)是一种可用于在线式烟气排放污染物自动监测的新型方法 ,它在不改变被测试样成分的前提下 ,可以同时对多种气体进行连续测量。对获得的吸收光谱数据由计算机处理 ,可实时记录烟气中各种污染物的含量 ,并对未知成分的气体进行判断。介绍了基于这种测量方法的测试系统的结构、工作原理 ,并利用所建立的测试系统进行了实验研究。测试结果表明 :采用差分吸收光谱法所测得的SO2 浓度在满量程范围内偏差均≤± 1 5 % ,完全可以满足烟气排放污染物 (SO2 )连续在线监测的要求     

紫外烟气连续监测系统在超低排放中的应用

介绍一种基于紫外差分吸收光谱(DOAS)技术,高温全程伴热的超低量程烟气连续监测系统(CEMS-2000L)。其技术指标达到:量程100 mg/m3,线性误差≤±1%FS,24 h零点漂移、量程漂移≤±2%FS,响应时间110 s。将该系统应用于超低排放污染源现场,并且与非分散红外仪表进行比对测试。比对结果显示:测量值与参比方法的绝对误差小于3 mg/m~3,表明高温抽取式紫外DOAS技术适用于固定污染源超低排放的检测需求。     

汽车排放气体测试仪示值误差测量结果不确定度评定

汽车排放气体测试仪（以下简称废气仪）是测量以汽油为燃料发动机的汽车（摩托车）排放气体中CO、HC或NOx等物质含量的计量检测设备.     

基于TDLAS技术的空间真空环境下温度测量技术研究

可调谐二极管激光吸收光谱(TDLAS)技术可用于气体温度的高精度快速测量,但目前TDLAS技术研究一般集中在正压范围内,真空环境下该技术的应用研究较少.空间真空环境由于压力极低,传统的接触式温度测量技术存在众多不确定性因素.本文从热力学温度定义出发,提出并分析了TDLAS技术测量空间真空环境下痕量气体分子振-转温度的可能性和精度.同时以C2H2分子1535.393nm和1535.432nm两条吸收谱线为例,分析了TDLAS技术测量气体分子振-转温度的方法和精度.分析结果表明即使压力达到1.0× 10-3 Pa,如果在实验中选取吸收强度大的谱线对,同时增加有效吸收光程,可以得到比较理想的吸收信号,实现气体分子振-转温度的测量.     

DOAS技术中差分吸收光学密度获取方法

针对差分吸收光谱技术(DOAS)获取差分吸收光学密度(OD)的技术特点,本文提出采用自适应神经模糊推理系统(ANFIS)来逼近DOAS测量谱中慢变成分,并依次获得痕量气体差分吸收光学密度.该方法根据DOAS系统获得测量谱的特点进行自适应调整网络参数,因此能较精确地分离慢变部分和快变部分.利用SO<,2>样气进行实验,结果表明ANIFIS比多项式函数更为灵活.基于AINFIS网络获取的OD进行浓度反演,提高了DOAS反演精度.     

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.     

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.     

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.