微珠填充环氧树脂复合材料的磨耗性能

制备了粉煤灰微珠/环氧树脂复合材料,并利用磨耗仪和邵氏硬度计测试了涂层试样的磨耗量和硬度。通过分析磨损表面微观形貌,探讨了固化工艺、固化剂和微珠添加量等对涂层试样磨耗性能的影响。结果表明,固化剂聚酰胺650的添加量显著影响涂层试样的硬度,当固化剂的含量增加时,涂层试样硬度随之增加,其表现出来的磨耗量也随之减少。试样的磨耗量也随固化工艺的不同而不同,在固化工艺为120℃1h时,试样的耐磨耗性能最好。随微珠添加量的增加,试样的磨耗量呈现先减少后增加的趋势,当粉煤灰微珠质量分数为20%时,试样的磨耗性能最好。     

生物质中温热熔预浸料用环氧树脂体系

采用生物质松香酸酐固化剂,通过配方设计和筛选,由配方体系成膜性、胶膜储存期、胶膜状态及DSC测试初步确定生物质环氧树脂体系的配方组成环氧树脂/固化剂/促进剂的质量比为100/60/3~4。由动态/稳态DSC测试和锥板旋转黏度计对体系的固化特征温度和黏度-温度-时间特性进行研究,结果确定树脂体系可在120~140℃完成固化,热熔法预浸温度范围60~85℃,其黏度在1500~5000mPa·s,其中70℃操作时间达180min。最后由红外光谱和DSC对生物质环氧体系的固化反应机理进行了研究。     

填料对环氧树脂固化动力学及触变性能的影响

通过差示扫描量热法(等温DSC和非等温DSC)研究了白水泥、膨润土、粉煤灰等无机填料对环氧树脂-聚酰胺体系固化动力学的影响;利用流变仪对体系的触变性能进行了测试。研究发现,环氧树脂-聚酰胺体系的固化反应级数在2～3左右,该反应具有自催化反应的特征,在90～100℃温度条件下,固化反应全段可用Kamal模型描述;而在反应温度较低时(50～80℃),固化前期可以用Kamal模型描述,后期反应由化学控制向扩散控制转变,只能用扩散控制的反应机理模型描述。在100份环氧树脂中加入5份稀释剂和50份无机填料,当填料为白水泥、粉煤灰以及粒径325目的膨润土时,在80℃条件下固化反应全段仍然可以用Kamal模型描述。当填料为粒径400目的膨润土时,体系的触变性显著增强,固化反应初始可以用Kamal模型描述,后期转为扩散控制,所以体系的流动性变差是导致固化反应动力学由化学控制转为扩散控制的主要因素。     

双固化3D打印弹性体光敏树脂的制备与性能

采用双固化体系设计,合成制备了两步固化可3D打印弹性体的光敏树脂。使用甲乙酮肟对聚氨酯预聚体进行封端,并通过红外光谱和差示扫描量热分析确定其对应的最佳解封温度为120℃;采用不同的丙烯酸酯类稀释剂配制光固化P树脂部分,与封闭聚氨酯预聚体及扩链剂组成的T树脂配制了双固化体系光固化3D打印树脂,采用平板流变仪确定了其打印温度应控制在30～35℃;对固化后的样品进行力学性能测试,发现当稀释剂采用玻璃化转变点高的稀释单体时,制备样品力学性能最好,接近于浇筑聚氨酯弹性体,在室温能保持良好的弹性。     

低温银包铜粉电子浆料的制备及性能研究

以银包铜粉和环氧树脂、固化剂、偶联剂、消泡剂为原料制备了低温银包铜电子浆料。采用丝网印刷将银包铜粉电子浆料印刷到玻璃片上,通过金相显微镜、万用表对固化后的试样微观和性能进行了表征。结果表明,当银包铜粉质量含量为50%,固化温度为70℃,固化时间为20min,流平时间为20min时,通过80目丝网印刷后制得的银包铜导电膜层导电性最佳为1.2Ω,在自然条件下放置120天电阻的变化率仅为23.1%,导电膜层图案完整光滑且具有良好的抗老化性能。     

环氧乙烯基酯树脂固化工艺及性能研究

采用三种不同过氧化物为树脂基体固化剂,对环氧乙烯基树脂进行固化。测定不同固化剂含量在不同温度下树脂的凝胶时间,通过对制备的树脂浇注体进行拉伸实验测试,差示扫描量热（DSC）法研究了不同树脂固化体系的反应放热特性,采用扫描电镜（SEM）观察了不同固化剂在其最佳固化工艺下树脂浇注体的断面的表面形态。本文确定了不同体系树脂胶液的固化剂含量及固化工艺,得到拉伸性能良好的环氧乙烯基树脂浇注体。     

丙烯酸酯改性环氧树脂的制备及其涂膜性能

针对混凝土表面腐蚀防护问题,制备一种丙烯酸酯改性环氧树脂涂膜并测试其物化性能。通过对比实验确定改性环氧树脂最佳种类、含量、反应时间、反应温度、固化剂用量、固化时间,并以红外光谱表征其结构。利用铅笔硬度、附着力、吸水率、耐酸碱盐腐蚀测试比较涂膜物理性能和耐腐蚀性能。通过差示扫描量热分析和热重分析研究涂膜热性能。结果表明,随着接枝聚合反应温度提高、反应时间增加,双酚A型环氧树脂E20在115℃下接枝聚合反应6h,可保证反应体系有较高单体转化率和接枝率。随改性环氧树脂所占比例升高,以质量分数为35%的丙烯酸酯改性环氧树脂为成膜树脂,15%的改性多元胺为固化剂,固化反应40min所制涂膜较为稳定,具备优良的耐腐蚀性和机械强度。     

溴化环氧/酚类固化剂固化体系的研究

由线型酚醛树脂/溴化环氧(A80)制备的板材不仅具有高的耐热性,而且在耐高温变色性、介电性能方面也有明显的改善,从而满足环氧覆铜板高性能化的要求,是一类具有广阔应用前景的环氧树脂固化剂.采用动态DSC方法研究了促进剂种类、促进剂用量对A80/Novolac、A80/线型双酚A酚醛(BPAN)和A80/线型双酚F酚醛(BPFN)体系固化反应的影响规律,并确定了固化工艺条件.结果表明BPFN、BPAN和Novolac作为溴化环氧A80的固化剂,在不加促进剂时,固化反应温度较高(超过200℃),而且反应速率很慢;促进剂2,4,6-三(二甲胺基甲基)苯酚(DMP-30)、六次甲基四胺(HMTA)和2-甲基咪唑(2-MZ)对三种线型酚醛/A80环氧体系的固化均有促进作用,随温度升高凝胶时间对数线性下降,随促进剂用量增大凝胶时间对数-温度曲线向低温方向平移;以2-MZ(0.1phr)作为促进剂,三种线型酚醛固化A80体系的固化反应放热峰的峰顶温度均为155 ℃左右,其中A80/BPFN体系的固化温度范围较宽,约55℃.     

基于复合材料湿法模压工艺的快速固化树脂体系研究

以适用于湿法模压工艺的快速固化环氧树脂体系为研究目标,研究了以改性胺类为主体的环氧固化体系特性。采用差示扫描量热仪(DSC)测试树脂体系的热性能,凝胶化时间测试仪确定树脂体系的固化时间,万能材料试验机表征树脂体系的力学性能,最后确定了快速固化树脂体系最佳的配比参数和浇注体性能。测试结果表明,在20%的固化剂用量和120℃的固化温度下,凝胶化时间达到48s,可以在5min左右完成固化,固化度达98%,拉伸强度达到63MPa,相比常规树脂体系和国内产品均有明显提升。     

环氧树脂基固体浮力材料的吸水性及压缩性

以不同固化剂固化的环氧树脂为基体,空心玻璃微珠(HGB)为分散相,加入硅烷偶联剂,制备得到固体浮力材料;研究了硅烷偶联剂添加量对固体浮力材料吸水性、45 MPa静水压力下吸水前后及干燥后压缩强度的影响;讨论了两种不同固化体系固体浮力材料性能的差异。结果表明:添加6%(质量分数)的偶联剂可以改善固体浮力材料的吸水性和压缩强度;酸酐固化剂甲基四氢苯酐(MeTHPA)固化的固体浮力材料的压缩强度高于胺类固化剂二氨基二苯基甲烷(DDM)固化的固体浮力材料的;固体浮力材料经过45 MPa静水压力吸水后及烘干后的压缩强度有不同程度的下降,添加偶联剂可以减小压缩强度下降的幅度。     

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...     

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.     

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.……     

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.     

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.