医用组织粘合剂的研究进展

医用组织粘合剂因其具有操作简便、无创粘合、即时密封和止血作用、可有效缩短手术时间等显著优势,获得了医疗领域的广泛关注,并逐渐成为传统手术缝合线的有效辅助或替代手段。目前,已有多种基于各类材料的商业化医用组织粘合剂被批准用于心脏、血管、肺等软组织的修复再生。然而,现有的大多数市售医用组织粘合剂仍然面临着粘合强度不够、功能单一、原料昂贵、生物相容性欠佳、安全隐患等挑战,临床上对于开发新型高效的多功能软组织粘合剂的需求极为迫切。在简要介绍各类软组织粘合剂的研究现状和粘合机制的基础上,对当前医用软组织粘合剂的研究热点、面临挑战及其临床转化应用情况进行了阐述,最后提出了未来的研究重点和发展趋势。     

贻贝粘蛋白的粘附成膜机理及应用研究进展

贻贝粘蛋白因超强的粘附性能几乎可粘附到所有的固体基材表面,使其在表面化学、生物医学、海洋工程等领域中具有广泛的应用价值,贻贝粘蛋白的这种强粘附性能与其分子结构、组成及功能有关。本文主要就贻贝粘蛋白分子的结构、组成、功能、粘附成膜机理、粘附强度及应用现状等问题进行综述。     

基于金属络合的多巴及其衍生物在表面功能化及自修复领域的研究进展

多巴因其独特的粘附性、可反应性及优异的生物相容性而受到青睐。为满足高分子材料的特殊功能性和受损后可再使用的要求,仿生贻贝的灵感启发科学家们利用多巴及其衍生物与金属间的络合作用实现材料的表面功能化及自修复性。主要对多巴及其衍生物与金属材料的作用机理、对其主要基团邻苯二酚与金属络合作用及其在表面功能化及自修复领域的应用进行了介绍与探讨。     

兰州化物所/香港城市大学在仿生水下可逆粘附材料研究方面获重要进展

正大多数胶粘剂在空气中具有优异的粘接强度,而在水中却很快丧失效果,这主要是因为水分子进入粘合界面处对胶粘剂分子产生水化/溶胀/降解作用,从而使得粘接性能迅速丧失。因此,水下高粘附材料一直是工程材料领域的研究难点与热点。科研人员通过仿生多巴     

仿贻贝蛋白聚合物在防污涂层中的应用进展EI北大核心CSCD

贻贝蛋白对不同基材表面都具备优异的黏附能力。研究表明,将贻贝蛋白的功能元-邻苯二酚基团引入到合成高分子中(仿贻贝蛋白聚合物)可有效模拟贻贝蛋白的功能特性。利用这种功能特性,通过在仿贻贝蛋白聚合物中引入防污组分可实现对不同基材的普适性强力黏附,是当前防污涂层领域中的研究热点之一。文中以仿贻贝蛋白聚合物的主链骨架的类型为主线,综述了近年来国内外仿贻贝蛋白聚合物在防污涂层中的应用进展,以期为研究人员探索新型的功能化贻贝仿生材料提供有益的借鉴和参考。     

结构仿生材料的研究进展

自然界中生物体的优异结构和特性给人类研究材料带来了灵感和启发.借鉴这些生物体的优秀结构特征是结构仿生材料的主要设计思想和方法.重点阐述了仿生增韧陶瓷材料、仿生粘附材料、仿生减阻材料、仿生减振材料和仿生系统应用在设计和制备方面的研究进展,并展望了结构仿生材料的发展前景,强调了多学科协作的重要性.     

从低维到高维的仿生材料制备及其应用进展

经过数十亿年的进化,自然界中的生物材料表现出许多卓越的性质和独特的功能。这些生物材料通常是由生物体内的有限组分在温和条件下组装而成,其优异的性能在很大程度上来源于复杂的多级结构,例如含邻苯二酚单元的贻贝粘附蛋白具有普适的强粘附力,珠-线结构的蜘蛛丝具有优异机械性能和集水能力,空心结构的北极熊毛发具有隔热保温作用,规则微纳结构的蝴蝶翅膀显示多彩的颜色,梯度多孔结构的柚子皮具有优异的阻尼减震效果等。以自然界的设计原理为灵感制造人工材料在材料科学和工程领域受到了极大关注,过去数10年,这方面的研究成果不胜枚举。总结了仿生材料在结构仿生方面的研究进展,选取了几个从低维到高维尺度上的典型例子概述了仿生材料的结构和功能之间的关系。     

包装通用术语国家标准

3.48 热熔粘合剂 hot-melt ab h esive加热时变成流体涂在包装材料上,冷却后使两层包装材料粘合的粘合剂.通常由热塑性聚合物制成.3.49 压敏粘合剂 pressure-sensitive ab h esive通常用于胶带或标签的一种粘合剂.在室温下能长期保持粘性,与各种不同材料表面接触时,只需用手指轻压即可粘合.3.50 衬垫材料、缓冲材料cushioning marerial为了防震而采用的包装材料.广义上包括表面保护材料,充填材料和支撑固定材料.     

医用骨粘合剂粘接性能研究进展

医用骨粘合剂使用方便,能保证粘接部位的完整性,同时避免机械固定所引起的应力屏蔽效应,因而在骨修复领域有较大的应用潜力。简要综述了几种常用医用骨粘合剂的综合应用性能,并重点介绍了常用医用骨粘合剂的粘接行为。结合医用骨粘合剂与骨组织的粘接机理,展望了医用骨粘合剂的发展前景。     

多巴胺对骨修复材料表面改性的研究进展

随着骨缺损病患的日益增多,对骨修复材料的要求越来越高,寻求有效的方法使骨修复材料实现功能化,以改善材料与骨组织之间的相互作用及促进骨组织快速修复成了关键所在。海洋生物贻贝分泌的粘附蛋白在水环境中展现出超强粘附性能,能牢固附着于各种材料表面。受粘附蛋白启发,研究发现多巴胺(Dopamine,DA)具有与贻贝粘附蛋白类似的结构和性能,其具有超强粘附性、化学反应活性以及生物相容性;特别是其对骨细胞有优异的粘附、增殖效果,有望用于骨修复材料的表面改性。着重介绍了DA的主要性能以及其在骨修复材料表面改性方面的研究进展。     

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.     

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.……     

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...     

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 ...