纳米晶稀土永磁材料的制备和磁性

介绍了纳米晶稀土永磁材料的制备和磁性方面的有关研究工作, 主要内容有: 低钕快淬Fe3B基钕铁硼新型纳米晶复合稀土永磁材料的相结构与磁性, 快淬Pr2Fe14B/α-Fe型纳米复合稀土永磁材料的微结构与永磁性, 快淬Sm-Co基稀土永磁材料的织构与磁各向异性的关系, 以及纳米晶稀土永磁材料的矫顽力机制和模拟计算研究等.     

钕铁硼稀土永磁材料腐蚀防护技术的研究进展

中国是钕铁硼稀土永磁材料生产、应用大国,钕铁硼稀土永磁材料是目前磁性能最高、应用范围最广、发展速度最快,也是当前工业化生产中综合性能最优的磁性材料。随着产业的不断升级进步,对其防腐蚀性能也提出了更多新的要求,钕铁硼稀土永磁材料的腐蚀问题已成为制约行业发展的瓶颈。回顾了用于钕铁硼稀土永磁材料的腐蚀防护技术,重点对新兴的腐蚀防护技术进行了追踪介绍,并对其发展和应用趋势进行展望。     

掺铕、混合稀土的P(MMA-co-St)材料的制备与性质研究

研究发现三异丙氧基稀土(铕或混合稀土)与甲基丙烯酸甲酯(MMA)/苯乙烯(St)混合后会形成凝胶体，经原位聚合后即制得掺稀土的P(MMA-co-St)改性材料．结果表明，掺铕或混合稀土的P(MMA-co-St)材料稀土含量高、透明性优良、耐热性好、贮能模量高；掺铕的改性材料呈现典型的配位敏化中心Eu3 的荧光光谱；掺混合稀土的改性材料在746．5，58l，525和513nm处出现很强的Nd3 特征吸收；ESEM显示了掺稀土的P(MMA-co-St)改性材料的微观形貌有较大的变化．     

北京有色金属研究总院稀土研究所

北京有色金属研究总院稀土研究所(原稀土研究室)成立于1958年,是中国最早从事稀土工业研究和开发的单位。主要从事世界最大的稀土矿——白云鄂博和中国南方离子吸附型稀土矿的综合利用研究。研究领域包括:矿石分解、湿法冶金提取、单一稀土元素分离和提纯、金属及合金的制备和稀土新材料的研制、开发等。新材料包括:稀土荧光粉、稀土电光源材料、稀土贮氢材料、稀土电池材料、稀土永磁材料、稀土抛光粉和汽车尾气净化稀土催化剂及装置等。     

稀土永磁纳米材料的化学法制备及其磁学性能

器件小型化、集成化的发展,对传统稀土永磁材料提出了小体积、高磁能积和综合磁学参数优良的要求,材料的纳米化是实现该目标的潜在途经.化学法在制备稀土永磁纳米材料中具有独特的优势,本文介绍了化学法制备稀土永磁纳米材料的最新进展,并展望了其未来发展方向.     

稀土永磁材料及其耦合磁体的化学合成与性能优化

稀土永磁材料是当今人类社会不可缺少的组成部分,自20世纪60年代问世以来一直在生产和生活中扮演着重要的角色。随着科技的进步和生活水平的提升,人们对工业产品及功能器件等提出了更高的期望,因此对稀土永磁材料的性能也有了更高的要求,包括能量密度、高温性能等。近年来,化学法成为合成稀土永磁材料常见的方法,通过"自下而上"的过程实现对产物形貌、尺寸等方面的精确调控,为制备高性能磁体提供了新的思路。化学合成对产物尺寸的控制在交换耦合磁体方面也有着独特的优势,可以通过精确控制双相耦合磁体中软磁相的尺寸以充分实现交换耦合效应,在提升磁体能量密度方面有着广阔的前景。从化学合成出发,介绍了近年来不同稀土永磁材料制备方面的工作,同时也总结了稀土永磁基耦合磁体在化学制备方面的进展和挑战,对未来化学合成稀土永磁材料的发展做出了分析和展望。     

稀土高新功能材料

在现代科学中,稀土元素在材料科学中的应用,使得材料科学取得了重大进展,出现了一批性能优越的稀土高功能材料,极大地推动了科学的进步和世界经济的发展。本文系统地介绍了稀土元素在高新功能材料中的应用,主要有稀土永磁材料、稀土食氢材料、稀土超志材料、稀土激光材料。２１世纪,稀土功能材料的应用领域将更加广泛。     

铸造锌铝合金稀土变质机制的电子理论研究

根据分子动力学理论建立了液态锌铝合金ZA27的模型，结合计算机编程构造出了ZA27合金相与液相共存时的原子结构模型，利用Reeursion方法计算了稀土固溶于晶粒内和富集于晶界前沿时的电子结构。由此得出：稀土处于相界区比在晶内更稳定，从而解释了稀土在相内溶解度很小，结晶时富集于相界前沿液体中的事实；稀土处于液态和晶态的结构能差相对于铝较大，解释了稀土在晶界前的富集使晶枝产生熔断、游离、增殖的观点。原子间的键级积分计算也表明，稀土处于晶界前沿液体中与铝相比不容易结晶到晶体表面，起到阻碍晶粒长大，细化晶粒的作用，这就从电子层次解释了稀土的变质机制。     

《中国稀土学报》征稿简则

一征文范围《中国稀土学报》(双月刊)是中国稀土学会会刊，由北京有色金属研究总院承办，北京大学协办，中科院院士、北京大学徐光宪教授任主编，报道稀土理论研究和应用技术的稀土类综合性学术刊物。本刊主要刊登有关稀土化学与湿法冶金；稀土金属学与火法冶金；稀土新材料(磁性材料、超导材料、纳米材料等)；稀土固体物理与固体化学：稀土应用研究；稀上分析检测；稀土地质、矿物和选矿等的研究论文、简报、快报和综述文章。     

稀土/MoSi2复合材料的干摩擦磨损性能

运用M－2型摩擦磨损试验机测定了不同载荷条件下稀土／MoSi2复合材料与45钢配对件的干摩擦磨损性能，采用SEM观察了摩擦副表面的形貌和X射线分析了磨屑相组成，并探讨了其磨损机制。结果表明：稀土／MoSi2和MoSi2与45钢干摩擦时，在负荷不超过150N的范围内，其摩擦系数μ和磨损率W与负荷p间较好地满足关系式：W（或μ）＝a bp cp^2 p^3 ep^4，两种均具有优异的耐磨性能，在80－120N范围，稀土／MoSi2复合材料的磨损率比纯MoSi2材料的至少降低了65％；稀土／MoSi2材料的磨损机制主要是粘着磨损。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.