静电纺纳米纤维膜用于重金属离子吸附的研究进展

静电纺丝制备的纳米纤维膜具有较高的比表面积和孔隙率,在重金属离子吸附领域有着广阔的应用前景。在简要阐述纳米纤维膜吸附重金属离子机理的基础上,主要从有机纳米纤维膜、有机-无机复合纳米纤维膜及无机纳米纤维膜等3个方面,介绍了近年来静电纺纳米纤维膜对重金属离子的吸附性能及其相关的研究进展,并针对目前纳米纤维膜吸附重金属离子应用研究中存在的一些问题给出了建议,为纳米纤维膜吸附重金属离子的后续研究提供参考。     

纳米无机粒子/聚合物共混体系分散机理研究进展

功能性纳米无机粒子在许多领域显现出独特的性能,然而纳米粒子团聚与分散的矛盾始终是制约其在有机-无机杂化材料中应用的关键。针对这一问题,从热力学和动力学的角度,分别综述了团聚体的分散过程及理论进展。基于分散的破碎和剥蚀机理,对团聚体的分散动力学进行了深入阐述。通过现有分散机理的概括,为纳米无机粒子/成纤高聚物体系的分散提供理论指导。     

聚酰亚胺／无机纳米杂化材料制备方法EI北大核心CSCD

本发明提供了一种聚酰亚胺／无机纳米杂化材料制备方法,首先合成适用于聚酰亚胺的无机纳米粒子改性剂——亚胺环基硅烷;采用溶胶-凝胶法制备无机氧化物纳米粒子,在溶胶一凝胶反应过程中加入改性剂亚胺环基硅烷,得到有机-无机复合体纳米颗粒;将有机-无机复合体纳米颗粒均匀分散于聚酰胺酸溶液中,经过加热处理得到聚酰亚胺／无机纳米杂化材料。本发明的聚酰亚胺／无机纳米杂化材料制备方法解决了纳米粒子分散的难题,在聚酰亚胺／无机纳米杂化材料中纳米粒子分布均匀,不团聚,有利于其各项性能的充分发挥。     

磁性荧光纳米复合微粒的制备方法及研究进展

磁性荧光纳米复合微粒可同时具有超顺磁性及荧光标记的功能,在生物医用领域中具有广阔的应用前景。综述了发光量子点、有机荧光材料及稀土元素离子分别与磁性纳米粒子组合而成的纳米复合微粒的制备方法及各自的优缺点,指出制备工艺简单且具有较好发光性能的稀土元素离子与磁性纳米粒子相结合的多功能微粒具有较好的发展前景。     

细乳液聚合制备有机-无机复合纳米粒子的研究进展

从细乳液聚合制备有机-无机复合纳米粒子体系的助剂、聚合方法及过程和提高无机纳米粒子包覆率的措施3个方面介绍了采用细乳液聚合法制备有机-无机复合纳米粒子的最新研究进展,并提出其目前存在的问题、今后的研究重点。     

聚砜有机-无机杂化改性膜的研究进展

聚砜膜具有良好的耐高温性、耐酸碱性能和高的机械性能等,被广泛用于膜分离领域.但由于聚砜膜的表面疏水性,使其在水处理等方面的应用受到一定限制.针对聚砜膜的有机-无机改性,综述了近年来采用无机纳米粒子,如金属氧化物纳米粒子、表面修饰的氧化物纳米粒子、二维(2D)层状材料、金属有机共价材料(MOFs)和其他纳米粒子对聚砜膜的杂化改性及其研究进展,并对存在的问题和应用进行评述和展望.     

有机-无机纳米复合光折变材料的研究与进展

在聚合物中掺杂无机半导体纳米粒子作为光敏剂制备的有机-无机纳米复合光折变材料是一种新型的光折变材料.详细介绍了有机-无机纳米复合光折变材料的制备方法、光折变性能及其存在的问题,展望了这类新型材料的潜在优势和发展前景.     

CuFeO 2纳米粒子的制备及其聚合物复合涂层的抗细菌粘附性

铜基纳米材料在催化、能量储存与转换、生物学传感等诸多领域具有广阔的应用价值,其中,CuFeO_2纳米材料的尺寸调控与形貌控制成为该领域的研究热点之一。采用水热合成法,以二价、三价铁盐和二价铜盐为金属离子源,通过柠檬酸钠和乙酸钠等有机小分子的调控,制备了有机分子修饰且单分散性良好的CuFeO_2纳米粒子,研究了反应时间及Cu~(2+)离子浓度对CuFeO_2纳米粒子形貌的影响。结果表明,反应8和10 h的CuFeO_2纳米粒子结晶性良好,随着Cu~(2+)离子浓度增加CuFeO_2纳米粒子的结晶性变差,Cu~(2+)离子浓度为2.8 g/L时,CuFeO_2纳米粒子尺寸均一、结晶性好。最后,探究了有机分子修饰的CuFeO_2纳米粒子复合涂层的抗细菌粘附性能,结果表明其对大肠杆菌具有良好的抗细菌粘附性。     

有机/无机纳米复合材料的研究进展

近年来纳米科技得到了迅速发展,由无机纳米粒子与聚合物复合制备的有机/无机纳米复合材料成为现代材料科技发展的重要方向.概述了有机/无机纳米复合材料的制备方法和性能特点;介绍了有机/无机纳米复合材料的应用领域,最后对它的发展前景进行了展望.     

聚合物/无机纳米复合材料的制备与应用进展

聚合物/无机纳米复合材料是聚合物改性领域中极为重要的研究方向,这类材料的制备方法是材料研究中难点和热点所在。主要对聚合物/无机纳米复合材料研究中几种重要的制备方法和国内外应用进展进行综述,重点介绍并比较纳米粒子直接分散法、溶胶-凝胶法、插层法、原位聚合法、有机-无机纳米复合膜法等方法的原理和特点。同时较为详细地介绍了聚合物/无机纳米复合材料在高性能复合材料和功能性复合材料研发中的应用情况和研究进展,并对现有研究中存在的问题进行分析,展望可开展的研究工作。     

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.     

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 ...