镍基催化剂催化氨硼烷水解产氢研究进展

氢气作为一种清洁能源,被认为是化石能源最理想的替代者。安全、高效且稳定的储氢材料的开发是当前氢能源应用研究中面临的最大挑战之一。氨硼烷(NH₃BH₃,AB)因其较高的储氢密度(146 g·L^-1,质量分数为19.6%)、安全无毒及高化学稳定性等特性成为一种重要的化学固态储氢材料。氨硼烷水解制氢反应条件温和,但需要在合适的催化剂存在的条件下进行。通过调节催化剂的活性组分、颗粒尺寸、活性组分的分散度、电子结构等,可显著提高氨硼烷水解产氢速率。综述了近年来氨硼烷水解制氢反应中镍基催化剂的研究进展,重点概述了镍单质、镍化合物以及镍合金催化剂在氨硼烷水解产氢中的应用,阐述了氨硼烷水解产氢反应机理,展望了氨硼烷水解产氢的发展趋势以及面临的挑战。     

氨硼烷水解制氢催化剂及其限域载体的形貌可控合成研究进展

氨硼烷具有高储氢含量(19.6%,质量分数),在普通贮存条件下稳定,被认为是最具有潜力的储氢材料之一。氨硼烷在常温下不易放氢,金属催化剂可显著提高水解放氢速度,是影响氨硼烷水解放氢的关键因素,然而金属催化剂纳米颗粒易氧化、易团聚,使用载体可使催化剂金属纳米颗粒分散于载体表面或孔道内部,防止氧化和团聚。催化剂及其载体的整体形貌很大程度决定了催化剂的比表面积、催化剂活性颗粒分布状态,从而影响了反应活性位点的数量及分布状态,对氨硼烷水解催化活性和催化剂的使用寿命具有重要影响,因此本文对氨硼烷水解催化剂及其限域载体的整体形貌按空间维度进行分类归纳,并对其可控合成方法和其对氨硼烷水解催化效果进行综述。     

氨硼烷热分解放氢的研究进展

氢能是一种理想的二次能源。氨硼烷(NH3BH3,AB)具有19.6%(wt,质量分数)的氢含量而受到广泛关注。氨硼烷热分解放氢具有放氢诱导期较长、有挥发性副产物等缺点。近年来,人们成功研究出几种促进氨硼烷热分解放氢,抑制副产物生成和经济、高效的氨硼烷再生技术。这些令人瞩目的技术为氨硼烷作为储氢材料应用于车载系统提供了广阔的前景。从这个角度,对近阶段氨硼烷的合成、热分解的改性和再生技术的研究进行了综述。     

氨硼烷水解制氢催化剂载体的研究进展

氢由于具有高效率和高功率密度而被认为是一种出色的清洁能源。化学储氢材料要求具有高的氢储存量。氨硼烷具有高氢含量(19.6%),且在普通贮存条件下稳定,被认为是有吸引力的储氢材料之一。由于氨硼烷在常温下不易放氢,故放氢催化剂成为氨硼烷放氢研究的核心技术和主要方向。金属催化剂可以显著提高水解放氢速度,是影响氨硼烷水解放氢的关键因素,但是金属颗粒催化剂一般都存在颗粒粒径生长过快、易团聚等缺点。为了解决这一问题,研究者选择不同的载体来分散催化剂,使催化剂金属分散在载体表面,防止团聚和过快增长,从而暴露更多活性位点,使催化氨硼烷放氢速率更快。文章将针对不同催化剂载体对氨硼烷水解的催化效果进行阐述。     

储氢材料研究进展

氢能作为一种新型的能量密度高的绿色能源,正引起世界各国的重视。储存技术是氢能利用的关键。储氢材料是当今研究的重点课题之一,也是氢的储存和输送过程中的重要载体。本文综述了目前已采用或正在研究的储氢材料,如金属(合金)储氢、碳基储氢、有机液体储氢、络合物储氢、硼烷氨储氢等材料,比较了各种储氢材料的优缺点,并指出其发展趋势。     

氨硼烷化合物成储氢材料新星

据报道，中科院沈阳金属研究所在新型氨硼烷化合物储氢材料研究方面取得了重要进展，在改善材料可控放氢性能方面达到了国际先进水平。这一成果的应用将推动氢燃料汽车产业发展。     

高密度储氢材料研究进展

氢是一种清洁的燃料,氢能是未来有发展前景的新型能源之一.氢的储存是氢能现阶段开发和利用的瓶颈.氢的储存方法有高压气态储存、低温液态储存和固态储存等3种,其中高压气态储存或低温液态储存不能满足将来的储氢目标.固态储氢是通过化学或物理吸附将氢气储存于固态材料中,其能量密度高且安全性好,被认为是最有发展前景的一种氢气储存方式.高密度储氢材料由轻元素构成,包括铝氢化物、硼氢化物、氨基氢化物、氨硼烷等,理论储氢质量分数均达到5%以上.综述了高密度储氢材料的研究进展,认为高储氢容量、近室温操作、可控吸/放氢、长寿命的轻质氢化物材料有希望达到燃料电池和移动氢源应用的目标.     

纤维状CuO/Co3O4的制备及其催化水解氨硼烷的研究

采用静电纺丝技术制备了一种纤维状钴铜双金属氧化物催化剂，并考察了催化剂中不同金属比例、不同催化剂制备方法、催化剂加入量、氨硼烷加入量以及水解温度对氨硼烷水解释氢的影响。结果表明：由于钴和铜之间存在强的协同效应，从而提高了催化剂的催化性能。当钴和铜的摩尔比为8∶1时，所制备的催化剂Co₈Cu₁O_x-NF性能最优，催化氨硼烷水解的活化能为38.41kJ/mol,反应转化频率(TOF)为2443.52mL/(min·g_metal),经过5次循环使用仍能保持较高的催化活性，该催化剂对氨硼烷水解具有良好的催化活性和循环稳定性。     

一种碳硼烷改性有机硅树脂的制备及其耐热性能

碳硼烷改性有机硅树脂是一种耐热性能优异的高分子材料,具有广阔的应用前景.然而由于聚合单体碳硼烷改性硅氧烷的合成条件苛刻,严重影响碳硼烷改性有机硅树脂的制备和应用.本研究利用羟基与异氰酸酯基间的加成反应,在温和的条件下合成了一种新型结构的碳硼烷改性硅氧烷-碳硼烷改性氨酯桥接丙基三乙氧基硅烷(CBR-Si),在此基础上经水...     

Cu@Co纳米颗粒合成及催化氨硼烷水解放氢性能

以Na BH4为还原剂合成了具有核壳结构的Cu@Co纳米颗粒,研究了其催化氨硼烷水解放氢性能。结果表明,Cu和Co的比例不同,Cu@Co纳米颗粒的催化活性也不同,其中Cu0.2@Co0.8的催化活性最高,室温下最大放氢速率达1364 m L min-1 g-1,活化能为59.1k J mol-1。Cu0.2@Co0.8催化氨硼烷水解反应对催化剂浓度是一级反应,对氨硼烷浓度为零级反应。Cu@Co核壳结构在催化反应中比Cu Co合金能够提供更多的反应活性位点,而且单质铜和钴之间存在的协同作用和电子效应在提高催化性能方面起着关键作用。     

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.……     

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