新型PST铁电薄膜的制备及其电性能研究

PST铁电薄膜是一种具有优良铁电、热释电和介电等性能的铁电材料.该材料在红外探测器、红外焦平面阵列、热成像器件、非易失性铁电存储器和大容量电容器等方面具有广泛的应用.PST铁电薄膜的制备方法多种多样,各具优缺点,不同的制备工艺对薄膜的性能有影响.叙述了PST铁电薄膜的制备技术、电性能和在热释电红外探测器方面的应用.     

高性能PZNFTSI陶瓷热释电材料与小面积红外探测器的研制

本探讨了小面积红外热释电探测器的探测率与热释电材料性能参数之间的关系，制备了热释电系数高达５．１×１０＾－４Ｃ·ｍ＾－２℃＾－１的ＰＺＮＦＴＳＩ型陶瓷热释电材料，并用其制作了一系列φ０．３ｍｍ的小面积探测器，性能最高达５．９×１０＾８ｃｍＨｚ＾１／２Ｗ＾－１，远远超过同样尺寸的ＬｉＴａＯ３晶体探测器。探测率Ｄ＾＊的测量结果与理论预测值符合得较好，克服了晶体热释电材料在小面积应用时的局限，为进一步     

PbSc0.5Ta0.5O3热释电材料及其红外探测器列阵

热释电红外探测器具有探测波长范围广、室温工作、无需致冷等优点。近年来，工作于介电方式下的PbSc0.5Ta0.5O3(PST)热释电材料由于具有热释电系数大，热释电探测优值高等特点，成为热释电应用研究的热点之一。本文综述了目前PST热释电陶瓷材料的介电，热释电性能及其探测器列阵的发展。由于小型化的要求，PST薄膜亦倍受关注，因此本文还对目前PST热释电薄膜的制备方法，薄膜的热释电、介电性能及薄膜型探测器结构和发展进行了概述。     

半导化的铁电相变热释电陶瓷材料

本文研究了 U_3O_8掺杂的 PZT 95/5系统多晶固溶体在两个菱方铁电相间相变的热释电性能及材料的电导特性。认为 U_3O_8的加入不仅改善了材料的热释电优值,同时作为一种施主杂质使材料半导化,实验结果证实了载流子的传输机理与假设一致,并求出了载流子的激活能。发现了该材料具有巨大潜在应用前景的电荷储存特性。最后制备了适用于热释电红外探测器的、具有高热释电系数、低介电常数及半导化的铁电相变热释电陶瓷材料。     

PMN-PT/P(VDF-TrFE)复合材料的制备与电性能研究

以铌铁矿预产物法合成的铌镁酸铅-钛酸铅(PMN-PT)陶瓷粉体和聚二氟乙烯-三氟乙烯共聚物P(VDF-TrFE)为原料,采用流延法在ITO衬底上制备了不同质量配比的PMN-PT/P(VDF-TrFE)复合厚膜。采用XRD及SEM分别分析了PMN-PT粉体的物相结构和复合材料的界面特征。通过测试复合材料的介电-温度曲线,计算出加载在陶瓷相上的极化分压与温度的关系,得到优化的极化温度。与常规的分步极化相比,探讨了在优化极化条件下陶瓷相含量对复合材料热释电性能的影响,结果表明在极化温度为110℃,PMN-PT质量分数为55%时,得到了热释电系数为58.6μC/(m2·K)的热释电复合厚膜材料。     

铁电薄膜的制备及应用技术研究

研究出具有特色的制备铁电薄膜的 sol-gel技术;制备出高质量、高可靠的 PLT、PZT、PYZT、BST”l、PbTiO3、BaTiO3、Bi4Ti3O12多晶铁电薄膜,PLT、PZT和伽里O3异质外延生长铁电薄膜;研制出铁电薄膜热释电单元红外传感器,8元、9元、1O元线列和8X8元阵列;研制出热释电火情探测器和热释电非接触式温度测试仪。     

红外热探测器陶瓷的进展

本文综述了红外热探测器的原理及相关的热释电陶瓷，对不同材料的性能作了比较，并介绍了红外热探测器的介电式工作模式和相应材料的性能。     

手性化合物S811的强热释效应及反铁电特性

用热释电流谱、介电温谱、电滞回线谱、差示扫描量热仪(DSC)、热台偏光显微镜(PLM)对手性化合物S811的电学性能及相变行为进行了研究.热释电流谱、介电温谱显示S811在相变附近具有强热释电电流,其最大热释电系数达到384nC/(cm2·K),介电常数在相变过程也发生了突变.电滞回线谱显示,在冷却过程依次出现了反铁电体-铁电体转变的双电滞回线和单电滞回线,揭示了S811作为热释电探测材料的应用潜力,拓展了其应用范围.     

PZT含量对PZT/PVDF复合材料性能的影响

采用流延工艺,在ITO玻璃衬底上制备了不同质量分数的锆钛酸铅(PZT)/聚偏氟乙烯(PVDF)热释电复合材料。采用X射线衍射方法对复合材料极化前后的物相变化进行了对比分析,通过扫描电子显微镜分析了不同PZT质量分数复合材料的界面特征。从热释电探测器件的实际要求出发,利用介电阻抗测试仪、动态法热释电系数测试系统等仪器系统地测试了复合材料体系中PZT含量对材料热释电性能和介电性能的影响。结果显示,在PZT质量分数为50%时,制得了热释电系数p为4.1nC/(cm2.K)的性能优良的热释电复合材料。     

红外热探测器陶瓷的进展

本文综述了红外热探测器的原理及相产的热释电陶瓷，对不同材料的性能作了比较，并介绍了红外热探测器的介电式工作模式和相应材料的性能。     

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.……     

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...     

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.……     

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 ...