高掺杂氧化镝的BSA玻璃的制备稳定性研究

为了研究高掺杂稀土情况下B2O3-SiO2-Al2O3体系玻璃的成玻璃性能,玻璃受到不同的化学溶液侵蚀时的抗腐蚀能力,及其腐蚀的机理与规律.通过采用扩张选点方法,探讨了的玻璃的形成区域图;采用UV3101-PC型分光光度仪,DTA和粉末失重法等测试手段研究了玻璃的化学稳定性.通过比较不同的H 浓度,不同场强的稀土离子,以及玻璃表面覆盖层等影响因素对玻璃化学腐蚀速率的影响规律,结果表明,BSA玻璃具有较好的玻璃形成能力;化学侵蚀过程中由于稀土离子的氢氧化物扩散与H 离子交换作用会影响玻璃化学侵蚀程度,因此玻璃耐酸性最差,耐碱性最好;稀土离子的场强越大,玻璃的抗腐蚀能力越强,化学稳定性越好;随着时间的延长由于玻璃表面产生了覆盖层,从而使得玻璃的溶解速率减缓.     

稀土硼铝硅酸盐玻璃结构及其耐碱性研究

本文通过块体法测定了玻璃的化学稳定性,同时采用MAS NMR研究了玻璃的结构.通过比较玻璃化学腐蚀速率,研究了不同稀土浓度的B2O3-SiO2-Al2O3-Sm2O3体系玻璃的结构及其在碱溶液中的抗腐蚀能力,探讨其侵蚀机理与规律.结果表明:碱溶液对玻璃的侵蚀是通过OH-离子破坏骨架造成.玻璃体系中三维网络阴离子群增加越多,玻璃结构越牢固,玻璃的抗碱能力越强;此外,由于稀土离子具有较强的积聚能力,适当地提高稀土氧化物在玻璃体中浓度有利于提高玻璃的抗碱性能.     

Cr2O3对高放核废料磷酸盐玻璃固化体的影响

在含高放核废料的玻璃固化体中添加了不同含量的Cr2O3，以考察其对玻璃固化体的结构和性质的影响．对添加Cr2O3的玻璃固化体进行了各种方法(溶出速率法，蒸汽水化侵蚀和试样坚固性法)的化学稳定性的测试．测试结果表明，Cr2O3的引入不会对玻璃固化体的化学稳定性产生不良的影响．与此相反，Cr2O3能抑制各种离子自玻璃固化体中沥析出来，改善玻璃固化体的化学耐蚀性．XRD内标法测定，Cr2O3在铁磷酸盐玻璃中的溶解度可达4．1％，是其在硼硅酸盐玻璃的3倍．FTIR和DTA的结果表明，不同含量的Cr2O3的引入，不会对玻璃固化体的网络结构造成显著的变化．Mossbauer谱表明，Fe^2 ／Fe^3 的比值随着Cr2O3的含量的增加而增大，说明Cr离子和Fe离子在玻璃熔制过程中发生氧化还原反应，形成的Cr^ 6有利于提高玻璃固化体的化学耐蚀性．     

稀土元素对磷酸盐玻璃微观结构的影响机制研究

为了探索稀土含量及种类对磷酸盐玻璃形成能力、析晶产物与形貌和微观结构的影响,利用固相熔融冷萃法获得了稀土磷酸盐玻璃。利用XRD证明了所研究的钙铁磷酸盐基质玻璃中最多可掺杂10%(摩尔分数)稀土氧化物(Y_2O_3、La_2O_3和Sm_2O_3),过量的稀土导致了样品析晶态REPO_4的形成;利用SEM-EDS表征了不同稀土样品析晶态的形状与组成。重点利用FT-IR光谱对稀土玻璃的微观结构进行了表征,不仅指认了微结构的振动模式,而且研究了稀土含量(Sm_2O_3)的增加以及不同稀土元素对玻璃结构的影响。研究发现,Sm_2O_3的加入导致了P=O键与P—O—P环谱峰的减弱,而Sm—O—P键的谱峰出现;利用高成拟合分析了不同谱带相对面积的变化规律,了解到不同稀土玻璃红外光谱P=O键相对面积与稀土离子的场强成反比,也掌握了稀土对磷酸盐玻璃不同结构单元的影响规律。     

ZnO-B_2O_3-P_2O_5无铅玻璃结构的红外光谱研究

借助于红外光谱研究了ZnO-B2O3-PzO5磷酸盐玻璃的结构,分别讨论了玻璃中B2O3/ZnO组成的变化和P2O5/ZnO组成的变化对磷酸盐玻璃结构的影响.结果表明:玻璃中硼氧三角体[BO3]随B2O3含量的增加而增多,而硼氧四面体[BO4]减少,当B2O3≥30%(摩尔含量)时,[BO3]急剧增多,导致玻璃的化学稳定性先缓慢下降后急剧下降;随P2O5含量的增加,[BO3]减少而[BO4]增加,当P2O5≥45%(摩尔含量)时,玻璃中的B3+主要以硼氧四面体[BO4]的形式存在.     

添加Bi2O3对ZnO-B2O3-P2O5-SrO体系封接玻璃结构和性能的影响

采用熔融法制备了ZnO-B2O3-P2O5-SrO-Bi2O3系无铅磷酸盐封接玻璃,研究了Bi2O3对该体系玻璃的结构、特征温度、热膨胀系数和化学稳定性的影响。结果表明,随Bi2O3含量的增加,玻璃的密度增大,Tg、Tf先下降后趋于平缓,玻璃的热膨胀系数先上升后趋于平缓;化学稳定性先增强后降低,当Bi2O3为7mol时,达到极小值。     

磷酸盐低熔封接玻璃的无铅化研究

从成本和低温化考虑,磷酸盐低熔封接玻璃最有可能取代商业铅基低熔玻璃。总结了近20年来研究较多的SnO-MO(M=Zn,Mg,Ca)-P2O5、ZnO-Sb2O3-P2O5、Na2O-CuO-P2O5、Na2O-Fe2O3-P2O5、硼磷酸盐和磷酸盐氧氮低熔玻璃系统的玻璃形成范围、制备方法、结构特征、性能参数和应用范围,总结的玻璃性能主要包括化学稳定性、转变温度、软化温度和热膨胀系数;指出硼磷酸盐、Na2O-CuO-P2O5、ZnO-SnO(Sb2O3)-P2O5、铁磷酸盐系统玻璃的化学稳定性基本达到或优于商业铅基低熔封接玻璃,磷酸和硼磷酸盐系统适用于中低温封接,而SnO-ZnO-P2O5和Na2O-CuO-P2O5应用于低温封接仍需解决转变温度大幅浮动、成本高及热膨胀系数等问题。     

硼硅酸盐包层玻璃化学稳定性的研究与结构分析

研究了紫外光纤用包层玻璃组分的变化以及外掺ZrO2对光纤包层玻璃化学稳定性的影响.结果表明,通过改变SiO2/B2O3、B2O3/Al2O3、B2O3/(K2O Na2O)的值,以及适当增加外掺ZrO2含量,可以明显提高碱硼硅酸盐玻璃化学稳定性.核磁共振和红外光谱分析表明玻璃化学稳定性提高的主要原因在于Zr4 的加入促进了玻璃内部的[BO3]层状结构逐渐转变为[BO4]网络状结构.     

碱金属氧化物对P_2O_5-ZnO-R_2O玻璃物化性能的影响

用传统高温熔融法制备了组成为35P2O5-50ZnO-15R2O的玻璃,研究了碱金属氧化物总摩尔量不变情况下,不同Na2O、K2O、Li2O含量对玻璃密度(ρ)、热膨胀系数(α)、玻璃转变温度(Tg)、化学稳定性及结构的影响。结果表明:随着K2O/(Na2O+K2O)比值的增大,玻璃的ρ逐渐减小,α、Tg逐渐升高。加入异种碱可以提高玻璃的耐水性。同时含有3种碱金属氧化物的玻璃的性能更加优越。玻璃由偏磷酸盐及焦磷酸盐构成。     

PbBr2-PbF2-P2O5玻璃的结构研究

采用红外光谱（IR）和X射线光电子能谱（XPS）等方法研究了PbBr2-PbF2-P2O5系铅卤磷酸盐玻璃的结构。结果表明，Pb^2 离子在玻璃中起着网络修饰阳离子和网络形成体的双重作用。当P2O5含量为60mol%时，Pb^2 离子主要是作为网络修饰体；当P2O5含量降低到50mol%时，一部分Pb^2 离子能够进入玻璃网络形成[PbO4]四面体或P－O－Pb键。Br^-和F^-离子达到一定浓度时就会进入玻璃网络，形成[PO4-nXn](X=Br或F，n=0-4)四面体使磷酸盐链长变短。玻璃中P2O5的含量不变时P－O－P键的比例也基本保持不变；当P2O5的含量降低时，P－O－P键和P－O^-键的含量都减少，P－O－Pb键的含量则明显增加。     

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.……     

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.     

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.     

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 ...