LDPE/LLDPE/APP阻燃体系的成型工艺和阻燃性能研究

以低密度聚乙烯和线性低密度聚乙烯(60:40)为基础物质,添加阻燃剂聚磷酸铵,构成阻燃体系,研究了阻燃体系的成型加工工艺参数和阻燃性能。研究表明:APP含量为30%时,阻燃性能达到FV-0级;造粒时,螺杆转速选择28～37r/min,牵引速度选择2.8～5.5m/min;制造哑铃型试样时,料筒温度在185～200℃之间,模具温度在91～105℃之间,预热5～10min,充模时间12～21s,制造矩形试样时,料筒温度在185～190℃之间,模具温度在85～110℃之间,预热5～10min,充模时间8～13s。     

铜铝复合板铸轧工艺优化及实验分析

本工作以水平式双辊铸轧机为研究对象,基于ANSYS Workbench平台的Fluent模块,用层流模型、凝固和融化模型处理,并用JMatPro软件获取1050Al的热物性参数,建立了铜铝复合板带铸轧过程的二维稳态有限体积模型。用正交模拟法研究了走坯速度、铝液浇注温度、铸轧区长度和铜带预热温度对铝液液相率分布的影响,并分析了速度迹线和温度场的分布规律。结果表明,铝液凝固受铸轧区长度和走坯速度影响较大,整体温度分布主要受铜带预热温度影响,并得出正交模拟参数优化范围为:走坯速度0.5～1.5 m·min~(-1)、浇注温度963～1 023 K、铸轧区长度65～80 mm、铜带预热温度300～673 K。选择走坯速度0.5 m·min~(-1)、浇注温度973 K、铸轧区长度80 mm、铜带预热温度300 K、铜带初始厚度2 mm进行铸轧实验,该铸轧工艺条件下铜铝复合板界面冶金结合状态良好,通过线扫描和能谱分析确定了金属间化合物Al_2Cu的存在。     

大尺寸Mo-1板轧制工艺研究

研究了加热温度、初火次变形率、退火温度等工艺参数对大尺寸Mo-1板组织和性能的影响.按照实验设计的4种热轧方案和工艺流程,采用350mm二辊不可逆式轧机和马弗炉对Mo-1板坯进行热轧、退火及温轧、冷轧实验;用金相显微镜观察了热轧及退火的组织;测试了0.2mm厚的成品钼板力学性能.结果表明,轧制温度选在1 250℃,初火次加工率选为37.5%,加工的Mo-1板综合性能比较好;热轧后的中间退火直接决定着后续工序的成败,退火温度应控制在850℃左右,保温时间应小于60min;为了减少热轧板坯表面和内部温差,改善板材组织和性能的各向异性,热轧时应预热轧辊,预热温度为200～300℃;采用换向轧制可提高板材的塑性、冲击韧性等,各向异性明显降低.     

高压粉末静电喷涂工艺及设备

粉末涂覆是表面处理新工艺,它在多种场合下代替溶剂性涂料涂装工艺,经济性好,效率高,无三废公害,在国内外已得到广泛应用。 1.粉末静电喷涂工艺参数工件与喷枪距离 100～200mm 静电电压 30～60kV 气源压力 0.5～0.6MPa 供粉压力 0.2～0.3MPa 稀释气压力 0.01～0.02MPa 供粉量 200～300g/min 悬链速度 1～1.5m/min 烘干温度 160～200℃ 2.高压静电自动喷粉设备     

大面积微结构辊对板热压印装置研发及工艺优化

目的 研发一种模块化辊筒对平板类型的微结构热压加工装置,研究不同模具结构下的辊压工艺参数对光学聚合物微结构成形的影响,研究大尺寸的PMMA样品的翘曲规律。方法 使用一种基于线接触的扫描连续辊压工艺,分别使用线槽模具、不锈钢网孔模具进行辊压实验,根据实验结果确定最佳工艺参数范围。结果 在辊筒温度为150～180℃、平板温度为25℃、辊压压力为200～500 N和辊压速度为1 mm/s的工艺条件下,甲基丙烯酸甲酯平板（PMMA）微槽阵列的线槽宽复制度最高可达90%,微圆柱结构在40 mm×40 mm PMMA衬底的覆盖率高达95%。结论 优化辊压工艺参数后,可以实现聚合物的大面积槽阵列和圆孔微透镜的稳定连续辊压成形。针对大面积光学聚合物翘曲的问题,进行了双面热辊压实验,发现二次成形后微透镜样品的最大高度偏差小于0.16 mm,翘曲现象得到了有效抑制。     

化学镀锡工艺参数对沉积速率、镀层厚度及表面形貌的影响

目前,铜基或铁基上化学镀锡存在连续性差、沉积速率慢等问题,为实现连续化学镀锡,提高沉积速率,设计了一种新的化学镀锡工艺,考察了化学镀锡主要工艺参数(镀液主成分、pH值、温度、施镀时间)对镀层表面形貌及厚度的影响.结果表明,最佳工艺参数为:20.0～25.0 g/L氯化亚锡,70.0～75.0 g/L次亚磷酸钠,70.0～75.0 g/L硫脲,75.0～80.0 g/L硫酸,5.0～8.0 g/L甲基磺酸,50.0～8.0 g/L EDTA,2.0～4.0 g/L对苯二酚,10.0～15.0 g/L乙二醇,0.5～1.0 g/L磷酸,0.5～1.0 g/L甲醛,0.5～1.0 g/L OP-10,温度80～85℃,pH值0.6～0.8.该工艺可实现连续化学镀锡,施镀3h厚度可达32.72μm.     

Cr-Mo-B系机械工程用钢高温流变行为及热加工图

在变形温度为850~1150℃、应变速率为0.1~10s -1 的条件下,对Cr-Mo-B系机械工程用钢进行高温热压缩实验。基于真应力-应变曲线,建立输入参数为温度、变形速率、应变和输出参数为流变应力的人工神经网络(ANN)模型。结果表明:神经网络模型的预测精度高,其预测流变应力的均方根误差为1.3858。根据动态材料模型理论(DMM),构建并分析材料在真应变为0.5和0.7时的热加工图,确定了最佳热变形工艺参数:当真应变ε=0.5时,变形温度为1050~1150℃、应变速率为0.1~0.4s -1 区域的功率耗散因子η≥37.20%;当真应变ε=0.7时,变形温度为1000~1150℃、应变速率为0.1~0.6s -1 区域的功率耗散因子η≥35.80%。     

室温离子液体中电沉积金工艺研究

为探索新型镀金工艺,研究了在氯化胆碱/尿素离子液体系中采用牺牲阳极法电沉积单质金n+工艺.采用扫描电镜(SEM)、X射线衍射(XRD)等手段考察了电流密度、主盐浓度、温度及时间等工艺参数对沉积速率的影响,并对镀层性能进行了测试.结果表明,在电流密度0.2～0.5 A/dm2,3～7 g/L主盐AuP-Ph3Cl,温度70～80℃,电镀时间30～40 min条件下,制得的金镀层光亮、细致,性能良好.XRD结果表明镀层为面心立方晶系.     

氧化石墨烯/酚醛树脂原位复合材料的热性能和动态力学性能

采用改进的Hummers法制备氧化石墨烯(GO),通过超声分散与苯酚、甲醛进行原位聚合,将所得原位聚合树脂与其它填料一起通过辊炼、模压成型制备GO/酚醛树脂(PF)原位复合材料。研究GO含量对GO/PF原位复合材料的热性能、力学性能、动态力学性能、蠕变和应力松弛的影响,使用扫描电子显微镜(SEM)观察复合材料的冲击断面形貌。研究结果表明,当GO加入量为1%时,GO/PF原位复合树脂的初始热分解温度比纯酚醛树脂(PF)提高了55.8℃;当GO加入量为0.25%时,GO/PF原位复合材料的冲击强度提高18.6%;当GO加入量为0.5%时,GO/PF原位复合材料的储能模量比纯PF复合材料提高78.3%,Tg提高了8.9℃。SEM观察发现,GO/PF原位复合材料的冲击断面凹凸不平,表明GO的加入能有效提高PF复合材料的力学性能。     

不同纳滤膜对苯酚的截留效果及其影响因素研究

以浓度<1 g/L的苯酚水溶液来模拟低浓度含酚废水,采用Alfa Laval Nakskov A/S错流式平板膜装置Lab Unit M20,比较了NF90、NF97、NF99、NF99HF 4种商业纳滤膜对苯酚的截留效果,结果表明:相同操作条件下NF97性能最好,25℃,3.0 MPa时对苯酚的截留率为79%.研究中亦考查了膜面流速(0.39～0.96 m/s)、温度(20～40℃)、压力(0.5～3.0MPa)、pH(3～11)、模拟废水的苯酚浓度(0.01～1 g/L)、盐浓度(1～3 g/L)对苯酚截留率的影响.结果表明:温度升高,苯酚截留率下降;压力增大可提高对苯酚的截留率,压力达到3.0MPa后,苯酚截留率随压力的变化已趋于平缓;pH值对纳滤膜截留能力的影响显著,在pH11时,NF90、NF97、NF99、NF99HF对苯酚的截留率分别为90%、97%、82%、75%;膜面流速对4种纳滤膜苯酚截留率的影响较小.对于低浓度含酚废水,可以考虑利用纳滤膜浓缩后,再用传统的萃取工艺处理,以实现低浓度含酚废水的综合利用,酚类物质有效回收,减小环境负荷.常温,膜面流速0.6 m/s,压力3.0 MPa,可以作为NF97纳滤膜浓缩低浓度含酚废水的参考工艺条件.     

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.……     

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.……     

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...     

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.     

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.     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...