生物活性陶瓷材料表面碳酸羟基磷灰石形成及其微观结构的研究

制备了羟基磷灰石(HAP)、生物活性玻璃、硅灰石以及羟基磷灰石和硅灰石的复合陶瓷等几种不同的生物活性陶瓷材料,在同一条件下对材料进行模拟体液(SBF)浸泡实验并用傅立叶红外光谱(FTIR)和场发射扫描电镜(FESEM)对试样表面进行了表征.结果显示,几种生物陶瓷材料经模拟体液浸泡后,表面都沉积了碳酸羟基磷灰石(HCA).不同的材料,表面沉积HCA的速度和微观结构有所差异.在硅灰石表面沉积HCA的速度最快,而在HAP表面沉积HCA的速度为最慢.HAP和硅灰石表面沉积的HCA层较为疏松,与此相比生物活性玻璃表面沉积的HCA层较为致密.这几种生物活性陶瓷材料表面沉积的HCA基本上都为光滑的球形颗粒.羟基磷灰石与硅灰石复合后不仅沉积HCA的速度发生很大变化,而且表面生成的HCA的微观结构也发生了改变.我们的结果显示,在模拟体液中材料表面HCA沉积速度和微观结构可以作为评价无机生物材料体外生物活性的一个重要方法,而通过羟基磷灰石和硅灰石复合可以调控材料的生物活性。     

含Zn、Mg生物玻璃的制备及性能研究

采用溶胶-凝胶法,在58S生物玻璃的基础上,分别用0.5wt％的氧化镁和氧化锌取代氧化钙制备了含镁和含锌的生物玻璃.压制的试样分别在600、700和800℃煅烧以做强度测试,并分析了600和800℃煅烧后的物相组成.结果表明,三种试样煅烧至800℃仍为玻璃态,而镁锌的掺入大幅度提高了生物玻璃的强度,这主要是因为Mg-O和Zn-O具有比Ca-O高的键能.模拟体液浸泡试验表明,镁和锌降低了羟基磷灰石的早期成核速度,但并不影响其后期的生长.浸泡三天后所有样品表面都被羟基磷灰石覆盖,表明了样品具有良好的生物活性.     

羟基磷灰石纳米棒的合成及其体外生物活性研究

在没有任何表面活性剂存在的情况下，利用水热法合成了尺寸分布均匀的羟基磷灰石（HAp）纳米棒，其长度和直径分别为0．5～1．51am和45～60nm。通过模拟体液（SBF）浸泡实验，研究了其体外生物活性。结果显示，浸泡10d后的羟基磷灰石纳米棒直径变为60～140nm，表面有新的羟基磷灰石层的形成，表明了该羟基磷灰石纳米棒具有良好的生物活性．     

含氟羟基磷灰石薄膜的溶胶-凝胶制备和溶解特性研究

含氟羟基磷灰石具有与羟基磷灰石相当的生物活性,在体液中具有较小的溶解度,是一种重要的生物材料.本文采用溶胶-凝胶方法,在钛合金基板上制备出氟含量可控、附着力强的含氟羟基磷灰石薄膜.薄膜经柠檬酸改性磷酸性缓冲溶液(CPBS)浸泡后表明,随着薄膜中氟含量增加,其溶解能力减小;随CPBS的pH值增加,不同氟含量的薄膜溶解量差别减小.含氟羟基磷灰石薄膜所具有的这些特性能很好地满足金属植入体表面的高性能生物活性改性材料的要求.     

SPS烧结制备生物活性镁黄长石陶瓷

钙硅基生物陶瓷具有良好的生物活性和细胞相容性, 在生物医疗领域具有广阔的发展前景。但是其粉体烧结性能差的缺点导致很难获得致密的陶瓷材料, 阻碍了其应用的进程。本研究采用化学共沉淀法制备了纯度高且烧结活性好的镁黄长石粉体, 然后采用放电等离子烧结技术(SPS)制备了镁黄长石陶瓷材料。通过X射线衍射(XRD)和扫描电子显微镜(SEM)表征了样品的组成结构和显微形貌, 并通过阿基米德法和模拟体液浸泡法分析了镁黄长石陶瓷样品的致密度和生物活性。研究结果表明, 采用SPS技术在1170℃、70 MPa保温5 min条件下可获得致密度超过99%的镁黄长石陶瓷材料。在模拟体液中浸泡3 d, 陶瓷样品表面出现磷酸盐的沉积, 浸泡7 d后生成了类骨羟基磷灰石, 说明SPS技术制备的致密镁黄长石生物陶瓷具有良好的诱导沉积类骨磷灰石能力。     

γ-硅酸二钙陶瓷的生物活性和细胞毒性研究

对溶胶-凝胶法合成的硅酸二钙粉体通过冷等静压成型,在1450℃下无压烧结,制备出高纯度的,γ-硅酸二钙(γ-Ca₂SiO₄)陶瓷,并对γ-Ca₂SiO₄陶瓷的体外(in vitro)生物活性和细胞毒性进行了研究.实验结果表明,该陶瓷具有优良的生物活性,在模拟体液(SBF)中浸泡72h后陶瓷表面沉积类骨碳酸羟基磷灰石层(CHA);材料溶解释放的钙、硅离子对成纤维细胞无毒副作用,在适当浓度下还能促进细胞增殖;该陶瓷还能支持骨髓间质干细胞(BMSCs) 的贴壁、黏附和铺展.因此,γ-Ca₂SiO₄陶瓷是一种生物活性优良和无细胞毒性的新型生物活性陶瓷材料.     

等离子体喷涂氧化钛涂层的生物活性研究

以纳米TiO₂粉末为喷涂原料, 采用大气等离子体喷涂技术在医用钛合金上制备氧化钛涂层. 利用酸和碱溶液对氧化钛涂层表面进行生物活化处理, 体外模拟体液浸泡实验考察涂层的生物活性. 采用XRD、SEM、FTIR、EDS等测试技术对改性前后氧化钛涂层的生物活性进行表征. 结果表明: 氧化钛涂层和钛合金基体的结合强度较高, 其值高达40MPa, 涂层的耐模拟体液腐蚀性优于钛合金. 酸和碱溶液表面改性后的氧化钛涂层经模拟体液浸泡可在其表面生成含有碳酸根的羟基磷灰石(类骨磷灰石), 显示良好的生物活性.     

磷灰石-硅灰石多孔玻璃陶瓷的制备与晶相结构研究

采用溶胶-凝胶法制备磷灰石-硅灰石(AW)生物活性玻璃陶瓷纳米前驱体粉末,前驱体粉末经热处理后,采用有机泡沫漫渍成型,烧结制备了多孔AW生物活性玻璃陶瓷.通过差热和热重分析、X射线衍射分析、红外图谱分析、扫描电镜、透射电镜等分析测试方法,对AW前驱体粉末的微观结构,及其在煅烧过程中的晶相转变进行了研究,确定了制备纳米级AW前驱体粉的最佳工艺条件,推测出微晶玻璃体中各晶相的析出温度,确定了溶胶-凝胶法制备多孔AW玻璃陶瓷的煅烧工艺,体外模拟体液浸泡实验表明材料具有较高的矿化功能和生物活性.     

磷酸钙在纳米羟基磷灰石／硅橡胶复合材料表面的仿生合成

将纳米羟基磷灰石，硅橡胶复合材料浸泡于模拟体液（SBF）中仿生合成了磷酸钙，利用IR、XRD、ICP和SEM等测试手段对表面沉积物进行表征．结果表明：在模拟体液中浸泡后，复合材料表面形成了分布均匀的以羟基磷灰石为主要成分的晶粒，表面羟基磷灰石的比例得到提高，生物学性能得以进一步改善；表明纳米羟基磷灰石，硅橡胶复合材料是一种生物活性材料．     

化学沉淀法制备纳米硅酸钙及其在模拟体液中的活性行为

以Ca(NO3) 2 ·4H2 O和Na2 SiO3·9H2 O为原料 ,聚乙二醇为分散剂 ,采用化学沉淀方法制备了直径 4 0nm的无定型纳米硅酸钙粉末 ,80 0℃热处理后得到平均直径 10 0nm的 β 硅灰石粉末。把两种粉末压制成块浸泡在模拟体液中 ,研究了两种粉体在模拟体液中的生物活性行为。结果表明 :由于无定型硅酸钙具有比β 硅灰石小的颗粒尺寸 ,且处于亚稳态 ,Ca2 的活性较大 ,无定型硅酸钙具有比 β 硅灰石较高的生物活性。在无定型硅酸钙表面不仅沉积了羟基磷灰石 ,而且也沉积了碳酸钙 ,以致于在浸泡初期阶段阻止了羟基磷灰石的沉积。经长时间浸泡后 ,无定型硅酸钙和 β 硅灰石表面都能沉积一层羟基磷灰石。     

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.……     

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.     

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