超细颗粒粒径分布分析仪的研制

利用一台三目生物显微镜制成超细颗粒粒径分布分析仪。利用标准光栅对系统的放大倍数进行了横向和纵向标定，通过实验发现该仪器的分辨率可以达到1.2μm。通过该仪器，可将颗粒的显微图像实时呈现在显示器上，根据其清晰度进行调焦。用Visual C 语言编写了粒经分布分析软件，利用它可以对同一玻片的不同视场有所选择和采样，去除背景噪声，将每次处理结果进行数据融合，实现对样品中超细颗粒的自动化检验和颗粒粒径参数的统计分析。因此这套系统实现了颗粒粒径检测人伫性到定量的重要转变，提高了颗粒检测和粒径分析的统计精度和置信度。     

微粒检测仪测量误差的不确定度评定

一、概述1.测量依据:JJF1290-2011《微粒检测仪校准规范》。2.环境条件:温度10℃~30℃;相对湿度≤85%。3.测量对象:微粒检测仪(GWF-8JD)。4.测量标准:GBW09702,10μm乳胶微粒标准物质。5.测量方法:在规定的环境条件下,待微粒检测仪稳定后,用校准用水进行检测,检测结果每10mL中含10μm及10μm以上的不溶性颗粒在10粒以下,含25μm及25μm以上的不溶性微粒在2粒以下。取平均粒径10μm的乳胶微粒标准物质对微粒检测仪粒子计数误差进行校准,重复测量3次,第1次测量数据不计,根据公式计算微粒计数的相对误差。     

尘埃粒子计数器宏粒子发生装置的研制

尘埃粒子计数器是用于检测评价洁净环境洁净度等级的仪器.目前,尘埃粒子计数器的溯源主要通过全国比对的方式对0.5μm的粒子浓度进行溯源,但制药、医疗器械等行业还普遍关注5.0μm粒径通道的计数准确性,然而5.0μm的粒径通道校准却存在气溶胶发生器浓度难控制、单分散性差的难题.本文针对这一技术难题,研制了一款针对尘埃粒子计...     

卷烟厂不同空调回风中粉尘的粒径分布

为了研究对选择空调过滤装置至关重要的卷烟厂不同生产区域的粉尘粒径分布,对某卷烟厂不同空调回风中粉尘的分粒径浓度进行测试和分析。结果表明:掺兑区粉尘产生量最大,制丝区次之,卷包区再次之,库房区及其他区最小;掺兑区、制丝区、卷包区空调应选用中高效过滤装置,库房区及其他区选用中效过滤装置,过滤装置性能宜重点考虑粒径大于10μm的颗粒,同时兼顾粒径小于10μm的颗粒。     

不同粒径微米/亚微米颗粒布朗运动的实验研究

利用显微粒子追踪测速系统(Micro-PTV)对四种不同粒径(2μm、1μm、0.71μm、0.52μm)的颗粒在纯水中的布朗运动进行了实验研究.使用波长为532nm的连续激光器、电子倍增CCD(EMCCD)相机以及放大倍率为63倍的显微物镜得到颗粒图像.对原始图像进行处理,借助于Video Spot Tracker软件获得相邻两帧图像中示踪颗粒的单步位移,在此基础上计算颗粒在纯水中的实验扩散系数,分别为0.191μm2/s,0.391μm2/s,0.579μm2/s及0.746μm2/s.将计算结果与采用Stokes-Einstein公式计算的无限大空间单个颗粒理论扩散系数进行了比对,偏差在10%以内,实验值略小.实验结果能够正确反映微米(μm)/亚微米颗粒布朗运动的特征.     

径向气流对旋风分级器的影响

为了改善分级器性能,试验引入径向气流对旋风分级器中的颗粒进行再次分离;试验物料选用催化裂化(FCC)和S-Zorb催化剂,对分级机进行了5组不同径向气速的试验。结果表明:该分级机对2种物料的最小切割粒径分别为6.5、3.3μm;试验中分级粒径为2μm时,FCC和S-Zorb催化剂的牛顿分级效率分别为91.9%和54.1%;径向风的引入破坏了康达效应的形成条件,有利于提高分级效果;进出口压降随着径向气流量的增大而降低;分级机对FCC催化剂的去"细"能力较好,对S-Zorb催化剂的去"粗"能力较好。     

一种用于单颗粒质谱的空气动力学颗粒浓缩装置仿真设计与试验研究

为提高在线单颗粒质谱SPAMS对低浓度环境下颗粒物的检测效率,本研究设计了一种基于虚拟撞击原理的空气动力学气溶胶浓缩装置。结合计算流体动力学Fluent仿真软件,对传统临界孔进样结构进行改进,孔径从原来的0.11 mm扩张至0.22 mm,并引入一个额外的前级泵抽离多余气体,使得SPAMS能在质谱真空压力不变的的情况下,将颗粒物从多余气体分离进入质谱检测系统,实现颗粒物浓缩进样。结果表明:颗粒浓缩倍数仿真值与实验值较为吻合,进样流量较原来提升3.4倍,在粒径0.2-5μm范围内,环境空气的颗粒浓缩倍数为3-8倍左右;气溶胶浓缩进样装置不仅能够实现颗粒浓缩进样,还提高了SPAMS对粗颗粒物的进样能力。     

超粗糙氧化锆复合陶瓷磁性剪切增稠光整加工特性

针对超粗糙表面氧化锆陶瓷材料的光整问题,配置磁性剪切增稠光整加工介质,利用设计的磁场发生装置,在主轴转速900 r/min、X轴进给速度10000 mm/min和加工间隙0.7 mm的实验参数下,探究不同磨粒和磨粒粒径对氧化锆陶瓷件加工的影响规律.对250μm绿碳化硅的磁性剪切增稠光整介质进行加工时,工件表面粗糙度值能在180 min内降低38％.10μm立方氮化硼配置的磁性剪切增稠光整介质,能使工件表面粗糙度值在210 min内降低41％.在磨粒粒径相同的条件下,随着磨粒硬度的提高,加工效率增大.在磨粒质量分数相同的条件下,磨粒粒径越小,获取的最终表面粗糙度值越小.观测结果表明,对比未加工表面,加工后的表面变得光滑,材料去除肉眼可见,验证了所提出方法的有效性.     

管内Cu-水微米颗粒流湍流强化传热研究

传统光管在高雷诺数下的传热效果不理想,因此提出在水介质中添加微米Cu颗粒作为工作介质来强化管内换热的方法。建立了Cu-水微米流的多相流传热物理模型,采用基于颗粒动力学的欧拉-欧拉双流体模型,对粒径分别为10μm、50μm、100μm和500μm,流速分别为1 m/s、1.5 m/s、2 m/s和2.5 m/s,颗粒体积分数分别为5%、10%、15%和20%进行了传热Nu和阻力损失f数值计算,结果表明:Cu-水微米流的努塞尔数Nu随雷诺数Re和颗粒体积分数的增大而增大,而随粒径的增大而总体趋势减小;摩擦因子f随颗粒体积分数的增大而增大,而随雷诺数Re增大而增小;传热综合性能评价因子η随颗粒体积分数的增大而增大,随着粒径的增大而总体趋势减小。粒径10μm的传热综合性能在研究的粒径范围内最佳,η达到1.1~2.3。     

磁性蓄冷材料HoCu2的雾化成形研究

采用旋转盘离心雾化设备制备了磁性蓄冷材料HoCu2粉末，并对雾化粉末进行了分析。结果表明，粒径＜154μm雾化粉末的比例较高，接近30％，粉末形态主要以球形颗粒为主，仅有极少量的形状不规则颗粒；粒径在矽φ154～300μm粉末的比例最大，收得率在60％以上，与粒径＜φ154μm粉末相比，残缺颗粒的比例有所增加；大尺寸粉末（＞φ300μm）的比例很低，仅为9％左右，除了少量带有缺陷的球形颗粒外，绝大多数为薄片状颗粒．雾化粉末的Cu含量为43．59％（质量分数），氧含量为0．055％（质量分数），为单一HoCu2相结构，无其它杂相存在。     

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.