化学法制备含锆沥青中锆的形态解析

采用X光电子能谱、X光衍射和背散射对含锆沥青中锆的存在方式进行了表征，结合实验现象推断出含锆沥青中锆是以氧化锆的方式存在的。含锆沥青制备过程中的反应实际上是氯化锆的水解和氧氯化锆的热分解反应，由于水解和生成的氯化氢气体的逸出，使新生成的氧化锆颗粒难以粘结在一起，从而在沥青中精细分散。在含锆沥青中的氧化锆颗粒在几微米尺度上，较粉末掺杂几十微米的颗粒有较大的改善。     

由沥青制备炭基凝胶的研究

以煤焦油沥青为原料,经过氧化、碱溶制备出水性中间相沥青,着重考察了制备条件对水性中间相沥青在水相中凝胶化的影响。结果表明：氧化温度、浓度和溶胶的pH值对水性中间相沥青的凝胶化有影响;水性中间相沥青（AMP）可以在较宽的pH值范围内形成凝胶。在碱性条件下,氧化温度降低、pH值升高和AMP浓度提高均可缩短炭基凝胶的凝胶时间;以强酸为絮凝剂在酸性条件下水性中间相沥青絮凝为炭基凝胶;在中性条件下,给溶胶中加入乙醇可形成炭基凝胶。     

双组元掺杂锆硅再结晶石墨的性能

以假烧石油焦、煤沥青、铅粉及硅粉为原料，采用热压工艺制备了一系列掺杂再结晶石墨。研究了掺杂组元对再结晶石墨的热导率、电阻率和抗弯强度的影响以及微观结构的变化．结果表明，掺杂锆使再结晶石墨的基本物理性能及其微晶结构有较大幅度的改善。在含锆石墨材料中，适当掺杂硅可提高材料的热导率，但是当锆的掺杂量为9％、硅的掺杂量大于2％(质量分数)时，再结晶石墨的常温热导率降低．双组元掺杂锆、硅使再结晶石墨的导电率和力学性能下降。在再结晶石墨中，掺杂的锆以碳化锆的形式存在，掺杂的硅大都以气态形式逸出，只有微量的硅以碳化硅的形式存在．     

碱式硫酸锆的制备条件研究

以氧氯化锆及硫酸钠为原料,通过正交实验,考察反应物浓度、配比及酸度等条件对碱式硫酸锆晶体质量及锆回收率的影响,探索了制备碱式硫酸锆较佳的工艺路线.利用该方法生产的碱式硫酸锆主品位大于37%,晶体平均粒径D50大于33μm,回收率达92%.     

高残炭率浸渍剂沥青的组成设计

以实现人工控制高残炭率浸渍剂性能为目的，提出了一种沥青组成设计的研究方法，探讨了改性沥青族组成分布与沥青性能之间以及参数与沥青族组成分布之间的关系，通过适当的实验和分析方法得到改性沥青工艺参数-组成分布-性能指标之间的经验式，并在此基础上根据目标沥青的性能要求确定改性沥青应具有的组成分布特点，进而得到合适的工艺参数。     

高温固相法制备锆英石工艺研究

为研究高温固相法制备锆英石的最佳工艺条件,以不同粒度的SiO2和ZrO2粉体为原料,在1 500℃条件下通过不同的保温时间进行锆英石的制备。利用激光粒度分析、X射线衍射、扫描电镜等手段对原料的粒度、物相与结构和微观结构进行表征。结果表明:不同粒度的SiO2和ZrO2粉体在1 500℃条件下通过保温1.5、3、4.5、6 h均可制备出锆英石,但d50=2.125μm的原料通过保温4.5、6 h所制备出的样品效果最好。利用高温固相法进行锆英石的工业化生产,原料的d50控制在2μm左右,在1 500℃条件下保温4.5 h的生产工艺比较合适,所制备样品的晶粒度主要集中在0.2~1.5μm之间。     

水性中间相沥青的制备研究

以煤焦油沥青为原料,以浓硫酸和浓硝酸为氧化剂,可得到易溶于碱性水溶液的水性中间相沥青。详细考察了沥青氧化条件对水性中间相沥青收率的影响,以及水性中间相沥青的元素和官能团组成。结果发现,反应温度、浓硫酸和浓硝酸的比例对水性中间相沥青收率影响存在一优化值,而反应时间、浓硫酸和浓硝酸的用量对水性中间相沥青收率先是线性的,当达到一定值后水性中间相沥青的收纺基本恒定。水性中间相沥青的组成是复杂的,根据其中化合物含氧官能团的数量和性质,它们可分别在不同pH值条件下制备而得。     

用悬浮法从沥青和树脂制备微米球炭

研究了以沥青和酚醛树脂为原料制备微米级炭小球的方法及工艺参数对小球收率及球径和球形度的影响。沥青炭球是通过在以聚乙烯醇为表面活性剂的甘油中加热沥青的四氢呋喃溶液得到的。相对于甘油沥青产率为5％。结果显示沥青球的收率和球径与沥青及聚乙烯醇的浓度具有密切关系。树脂微球是在500mL反应器中，以水为加热介质，聚乙烯醇为表面活性剂，加热RESOL型酚醛树脂的乙醇溶制得的。结果表明树脂的浓度对固化树脂微球的球径具有显著影响。     

Sol—Gel法硅基铁电薄膜研究

介绍了用溶胶－凝胶方法制备Ｐｂ（Ｚｒ０．５３Ｔｉ０．４７）Ｏ３（ＰＺＴ）铁电薄膜的工艺流程。以硝酸锆、醋酸铅和钛酸四丁酯为原料,在９００℃,３０ｍｉｎ退炎条件下制备了硅基ＰＺＴ铁电薄膜。实验分析结果显示,ＰＺＴ铁电薄膜的晶化很完善。研究了ＰＺＴ铁电薄膜与硅之间的界面及其对铁电薄膜品质的影响。并在此基础上实现了制备ＰＺＴ铁电薄膜的低温改进工艺。     

焦炭颗粒的平均细度对沥青基炭复合材料性能的影响

采用新型模压半炭化成型工艺制备出高密度、低成本的焦炭颗粒增强沥青基炭复合材料。研究了焦炭颗粒的平均细度对焦炭颗粒增强沥青基炭复合材料的密度和抗压强度的影响趋势，并从数学上分析了密度对抗压强度的影响规律。结果表明：沥青基炭复合材料的密度和抗压强度随焦炭颗粒平均细度的增大而增加。在本试验条件下，当沥青焦的平均细度由44．2目增加到206．3目，沥青基炭复合材料的密度和抗压强度可从1．28g／cm^3和10．1MPa增加到1．77g／cm^3和55．0MPa。     

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.     

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...     

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.……     

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 ...