预钙化处理后的钛表面磷灰石涂层的形成

本研究采用碱液处理钛样品，并进行预钙化处理，在模拟体液（SBF）中浸泡，能在较短时间内形成表面致密的磷灰石涂层，碱液处理使钛表面生成了钛酸钠及氧化钛等物质，在SBP中浸泡时，会发生水解而使表面形成带负电的Ti-OH基团，预钙化处理使带负电的钛表面由静电引力而聚集了大量的Ca^2 离子，Ca^2 能吸引带负电的HPO4^2-到达表面，从而使表面附近能在较短时间内达到钙－磷过饱和，Ca^2 离子又能使表面附近的pH值增大，Ca^2 离子和HPO4^2-离子的活度积就增大，从而刺激了磷灰石晶体的成核与长大，最终形成表面磷灰石涂层。     

仿生磷灰石涂层与钛基体结合强度的划痕法实验

本文采用碱热处理及SBF浸泡的方法在钛片上制备了仿生磷灰石涂层,并采用AES进行表面成分-深度分析,划痕法测定磷灰石涂层与基体的结合强度.结果显示,经碱热处理而制得的钛表面仿生磷灰石涂层与基体结合的界面为成分梯度界面,二者的结合要通过成分含量呈梯度变化的过渡层:Ca、P元素的含量从表面到基体逐渐下降,Ti元素的含量逐渐上升.热处理有利于提高涂层的基体结合强度,其原因是热处理使SBF中形成的磷灰石的晶核细小而均匀,使得表面涂层与基体之间的结合更为紧密.预钙化处理后形成的磷灰石涂层与金属之间仍为成分梯度界面,因此对涂层的基体结合强度影响不大.     

类骨磷灰石的结构分析与形成机制研究

采用在模拟体液(SBF)中浸泡材料的方法,在致密羟基磷灰石(HA)表面形成类骨磷灰石层,利用XRD和FT-IR分析表面相结构,SEM观察表面形貌,X光电子能谱分析表面化学组成及其价态.结果表明,表面新生相为含PO43-、CO32-和OH-的低结晶度的类骨磷灰石微晶.其形成机制属于溶解-沉淀型,HA陶瓷浸泡与SBF液中,首先产生表面溶解,使表面附近Ca2+、PO43-等离子浓度升高,然后通过静电吸引,在其表面吸附、成核、长大,形成类骨磷灰石新相.     

化学处理制备多孔钛表面磷灰石涂层

本文中采用化学方法制备多孔钛表面磷灰石涂层。多孔钛样品经HCl H2SO4混合溶液及NaOH水溶液处理后，表面形成氧化钛及钛酸钠层。在过饱和Ca—P溶液中浸泡一段时间，磷灰石涂层沉积到多孔钛的表面。涂层由片状的垂直于金属表面的磷灰石和OCP结晶组成，不含CO3基团。涂层的Ca／P比约为1．46左右，小于羟基磷灰石的Ca／P化学计量比。涂层厚度约50μm，涂层后多孔钛的最大孔径约为150μm，可以满足临床使用要求。     

钛涂覆多孔羟基磷灰石涂层的制备及其生物活性

在纯钛基体表面通过电泳沉积的方法制得壳聚糖/羟基磷灰石(CS/HA)复合涂层, 然后将复合涂层烧结形成多孔HA涂层。采用SEM对多孔HA涂层的形貌进行观察, XRD分析涂层的物相组成, 粘结拉伸实验测定涂层与基体的结合强度, 1.5倍人体模拟体液(1.5SBF)浸泡测定涂层的生物活性。结果表明: 当悬浮液中CS与HA质量比为1∶1时, 制得的CS/HA复合涂层经过700℃烧结处理, 涂层中CS热分解致孔形成多孔HA涂层, 孔径在10~25 μm, 涂层与基体的结合强度可达19.5 MPa; 在1.5SBF中浸泡5天后, 多孔HA涂层表面完全碳磷灰石化, 呈现较好的生物活性。      

纯钛表面仿生矿化性能优化的研究

采用不同的碱液处理浓度和处理时间在80℃下处理纯钛的表面并在模拟体液(SBF)中进行仿生矿化.结果表明随着碱液处理浓度和处理时间的增加,纯钛表面在模拟体液中仿生矿化的能力增强.碱液处理的浓度是影响纯钛表面仿生矿化能力的主要因素.经10M/L的碱液处理48h后,纯钛表面生成的是具有(002)和(004)晶体取向的类骨磷灰石(HCA),HCA晶粒生长较大,相互连接形成空间紧凑的结构.     

生物活性钛涂层

真空等离子喷涂的钛涂层经 ５．０ｍｏｌ／Ｌ ＮａＯＨ溶液处理后,将其浸泡在含 Ｃａ^２＋、ＨＰＯ_４^２－的模拟生理体液（ＦＣＳ和ＳＢＦ）中,考察涂层诱导羟基磷灰石生长过程,并评价其生物活性．用ＳＥＭ观察碱处理前后和在模拟生理体液中浸泡后钛涂层的形貌,用ＡＥＳ分析了碱处理前后钛涂层的表面成分;用ＸＲＤ、ＦＴ－ＩＲ和ＥＤＳ表征浸泡后涂层表面生长物的结构和成分;并测量了处理后钛涂层在浸泡过程中溶液中离子浓度和ｐＨ值的变化．结果表明,经处理的钛涂层在模拟生理体液中能诱导羟基磷灰石在其表面生长;在ＳＢＦ和ＦＣＳ分别形成碳酸羟基磷灰石层和含氧磷灰石的羟基磷灰石层．钛涂层的活性是由于碱处理后表面形成了网状和纤维状结构的Ｎａ－Ｔｉ－Ｏ化合物．这种化合物在模拟生理溶液中释放Ｎａ^＋,吸收Ｈ^＋;形成水化钛酸盐,诱导羟基磷灰石成核生长．     

单晶硅表面溶胶-凝胶法制备磷灰石涂层的研究

采用溶胶-凝胶法在单晶硅表面制备了磷灰石(apatite,AP)涂层。借助SEM、EDS、XRD研究了单晶硅表面AP涂层的形貌结构与成分特征,通过模拟体液(simulated body fluid,SBF)浸泡实验研究了硅基AP涂层的体外诱导性能。研究结果表明,在500℃保温2h即可使sol-gel层转变为较致密的AP涂层,700与800℃分别保温2h得到的硅基AP涂层晶体长大且出现间隙,涂层的结晶性随热处理温度升高而增加,在800℃处理未出现AP的分解;SBF中浸泡1周后,AP涂层未出现剥离单晶硅的现象,且能够诱导骨状磷灰石新沉积层的形成,体现出较好的体外诱导性能。     

溶胶-凝胶法在多孔钛表面制备二氧化钛生物涂层

室温下利用溶胶-凝胶法在多孔钛表面制备TiO2薄膜,并分别于不同温度热处理.利用电化学工作站测试不同温度煅烧后的TiO2薄膜在0.9%NaCl生理盐水中的耐腐蚀特性;利用XRD、SEM测试技术研究样品在模拟体液(SBF)内浸泡不同时间后的生物活性和显微结构.结果表明,600℃退火的TiO2薄膜的生物活性最强,只在SBF中浸泡10天就形成表面致密的磷灰石涂层,并且涂层的结晶细小而薄,没有破坏多孔钛的孔隙结构;800℃退火的TiO2薄膜因其最为致密,在生理盐水中的耐腐蚀性最好.     

后处理工艺对阳极氧化钛生物活性的影响

钛及钛合金由于具有良好的力学、生物学性能,已成为良好的骨修复和替换材料。为了改善钛的生物活性,首先采用两步电化学阳极氧化法对金属纯钛进行表面改性,即使之表面形成多孔纳米结构,然后对样品进行不同的后处理,如450℃热处理,NaOH处理,NaOH-CaCl2处理,最后将后处理样品浸泡在人体模拟液(SBF)中,研究磷灰石在样品表面的生长情况。采用X射线衍射(XRD)、带能量散射谱(EDS)的场发射扫描电子显微镜(FE-SEM)、傅里叶变换红外光谱(FT-IR)、电感耦合等离子体发射光谱仪(ICP-OES)等对生成的磷灰石的物相、形貌、元素组成等进行表征。结果表明,非晶TiO2纳米管阵列不能诱导磷灰石在其表面生成,而经450℃退火处理后形成的结晶良好的锐钛矿相TiO2纳米管阵列具有一定生物活性,即可诱导部分磷灰石颗粒在其表面生成。进一步经NaOH-CaCl2溶液后处理可加速羟基磷灰石在样品表面的形成速度,样品在模拟体液(SBF)中浸泡8d后,表面生成的磷灰石厚度约为5μm,磷灰石层是由大量球形颗粒堆积而成的,而球形颗粒是由无数纳米薄片组成的花状结构。     

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.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from