新型稀土富铁永磁化合物NdFe10Mo2Cx的制备和磁性研究

用气－固反应将碳原子渗入到母体合金ＮｄＦｅ１０Ｍｏ２的晶格间隙位，形成稳定的化合物ＮｄＦｅ１０Ｍｏ２Ｃｘ，其晶体结构保持ＴｈＭｎ１２型方结构不变，但晶胞积增大３％左右，居里温度提高１１０Ｋ以上，且ＮｄＦ３１０Ｍｏ２Ｃｘ具有单轴各向异性，磁晶各向异性场ＨＡ达到９２３３．６ｋＡ／ｍ．结果表明，ＮｄＦｅ１０Ｍｏ２Ｃｘ具备了研制高矫顽力永磁体的内禀磁性，另外，穆堡尔谱实验表明，ＮｄＦｅ１０Ｍｏ２Ｃｘ中不同     

合金元素对HDDR工艺Nd—Fe—B合金粉显微组织和磁各向异性的影响

研究了Ｃｏ和Ｚｒ对ＮｄＦｅＢ合金ＨＤＤＲ粉显微组织和磁各向异性的影响。磁测量结果表明，Ｎｄ１３Ｆｅ８０．４Ｚｒ０．１Ｂ６．５基本上是磁各向同性的，而Ｎｄ１５Ｆｅ６６．９Ｃｏ１１Ｚｒ０．１Ｂ７合金粉末则具有较强的磁各向异性，显微组织观察发现，退火后ＮｄＦｅＢ合金中存在一些富Ｚｒ的新相，并且这些新相在ＨＤＤＲ处理过程中并不发生变化，而Ｃｏ在一定程度上抑制了这些新相的出现，不仅减小了该相的体积份数而且降低了其中的Ｚｒ含量。分析表明，对ＮｄＦｅＢ合金化学成分进行优化以保证硬磁相内溶有一定量的合金元素（例如Ｚｒ）是获得各向异性ＨＤＤＲ粉的关键所在。     

添加Al、Mg、W、Mo对烧结Nd-Fe-B磁体磁性能与显微组织的影响

研究了在烧结ＮｄＦｅＢ磁体晶间添加Ａｌ、Ｍｇ、Ｗ、Ｍｏ等合金元素对显微组织和磁性能的影响。实验结果表明：低熔点合金元素Ａｌ、Ｍｇ能显著提高ＮｄＦｅＢ磁体的矫顽力，略微降低剩磁，对磁体的热稳定性无影响；高熔点合金元素Ｗ、Ｍｏ在不降低剩磁的情况下亦能提高磁体的矫顽力，但效果不如Ａｌ、Ｍｇ明显。显微组织分析表明，在添加低熔点和高熔点合金元素的磁体晶间发现了两种不同的新相。矫顽力的提高可归于晶间新相的出现。进一步分析表明，与传统的合金化相比，对ＮｄＦｅＢ磁体晶间区域进行微合金化是改进ＮｄＦｅＢ磁体组织与性能的一种更为有效的手段。     

电镀及化学镀磁记录介质薄膜的最新进展

本文综述了近年来国外电镀及化学镀磁记录介质薄膜的最新研究进展、电镀及化学镀镀液组成、工艺条件及其对薄膜性能的影响、存在问题及发展方向等．磁记录介质薄膜的制备，过去一直采用溅射方法，近年来国外开展了电镀及化学镀方法制备的研究．电镀方法包括水溶液电镀（如：Ｎｉ－Ｆｅ、Ｆｅ－Ｃｏ合金等）和非水溶液电镀（如Ｔｂ－Ｆｅ、Ｎｄ－Ｆｅ、Ｔｂ－Ｆｅ－Ｃｏ合金等），化学镀则是在Ｎｉ－Ｐ、Ｃｏ－Ｐ合金的基础上，通过添加其它金属盐，得到磁记录介质薄膜，如：Ｃｏ－Ｎｉ－Ｐ、Ｃｏ－Ｗ－Ｐ、Ｃｏ－Ｍｎ－Ｐ、Ｃｏ－Ｎｉ－Ｒｅ－Ｐ合金等     

纳米尖晶石型Co2MnO4的形成过程及其F-T反应性能

用溶胶凝胶法制备了尖晶石型Ｃｏ２ＭｎＯ４超细粒子，用ＤＴＡＴＧ，ＸＲＤ，ＴＥＭ，ＦＴＩＲ等手段研究了Ｃｏ２ＭｎＯ４超细粒子的形成过程，进而用反应评价结合ＸＲＤ，ＸＰＳ，ＢＥＴ比表面积测试研究了Ｃｏ２ＭｎＯ４催化剂的比表面积和表面结构与其ＦＴ反应性能间的关系．结果表明，Ｃｏ２ＭｎＯ４超细粒子可以在较低温度（２５０～３５０℃）下形成，并具有粒度小，分布均匀等特点．用该法制备的超细粒子Ｃｏ２ＭｎＯ４，其催化活性明显优于相同组成的大颗粒催化剂．     

金属羰基化合物的结构对氧原子转移反应速率的影响

本文研究了氧化三甲胺Ｍｅ３ＮＯ与羰基簇合物Ｍ４（ＣＯ）１２－ｎＬｎ（Ｍ＝Ｃｏ，Ｉｒ；ｎ＝１，２；Ｌ＝磷配体）的氧转移反应动力学，讨论了反应机理。反应符合二级速率方程：ｒ＝Ｋ２［Ｍｅ３ＮＯ］［Ｍ４（ＣＯ）１２－ｎＬｎ］Ｍ４（ＣＯ）１２－ｎＬｎ的氧转移反应活性呈现如下顺序：中心元素不同时Ｃｏ４（ＣＯ）１２－ｎＬｎ＜Ｉｒ４（ＣＯ）１２－ｎＬｎ；取代配体不同时Ｍ４（ＣＯ）１２－ｎ（Ｐ（ＯＭｅ）３）ｎ＞Ｍ４     

氧缺位铁酸盐的制备及结构与还原行为的研究

在３５８Ｋ下用２００ｍｌ／ｍｉｎ的空气氧化碱性悬浮液合成了ＭＦｅ_２Ｏ_（４＋δ）（δ≥０，Ｍ＝Ｆｅ、Ｃｏ、Ｎｉ、Ｍｎ），并在５７３Ｋ下用４０ｍｌ／ｍｉｎ的Ｈ_２还原ＭＦｅ_２Ｏ_（４＋δ）制备了氧缺位铁酸盐ＭＦｅ_２Ｏ_（４－δ）（δ＞０）。用ＸＲＤ、Ｍｓｓｂａｕｅｒ谱等测试方法对铁酸盐的结构进行了表征，考察了铁酸盐的组成及第二金属组分（Ｃｏ、Ｎｉ、Ｍｎ）对铁酸盐还原性能的影响。在Ｈ_２还原３ｈ内，铁酸盐氧缺位程度随还原时间增加而增大，晶格常数也相应增大；５ｈ以上，铁酸盐将被还原为ＭＯ－ＦｅＯ或α－Ｆｅ，晶格常数几乎不变。按Ｆｅ、Ｃｏ、Ｎｉ、Ｍｎ顺序，ＭＯ与ＦｅＯ的相互作用能力、ＭＯ－ＦｅＯ固溶体的稳定性及铁酸盐还原为ＭＯ－ＦｅＯ的能力均增强，ＭＯ－ＦｅＯ进一步还原为α－Ｆｅ的能力却减弱。     

Eu_（0．5）RE_（0．5）Fe_（0．5）Mn_（0．5）O_3的~（57）Fe Msosbauer谱研究

利用固相反应合成了Ｅｕ_（０．５）ＲＥ_（０．５）Ｆｅ_（０．５）Ｍｎ_（０．５）Ｏ_３（ＲＥ＝Ｌａ，Ｐｒ，Ｎｄ，Ｓｍ，Ｅｕ，Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｙ）等化合物。测量了其ＸＲＤ谱及~（５７）ＦｅＭｓｓｂａｕｅｒ谱．实验发现，随着ＲＥ原子序数的增加，样品的晶胞体积减小，Ｆｅ在化合物中处于Ｆｅ~（３＋）的高自旋状态，~（５７）Ｆｅ的四极裂矩与样品的畸变参数Ｄ成线性关系。     

用聚乙二醇—硫酸铵—铝试剂体系萃取分离铁（Ⅲ）铝（Ⅲ）,铜（Ⅱ）钴（Ⅱ）…

研究了在聚乙二醇－硫酸铵－铝试剂体系中Ｆｅ（Ⅲ），Ａｌ（Ⅲ）、Ｃｕ（Ⅱ）、ＣｏⅡ）Ｃｄ（Ⅱ）Ｍｎ（Ⅱ）、Ｎｉ（Ⅱ）的萃取分离行为。结果表明，在ＰＨ５．０－６．５ＨＡｃ－ＮａＡｃ缓冲溶液中，Ｆｅ（Ⅲ）、Ａｌ（Ⅲ）可被ＰＥＧ相几乎完全萃取，而Ｃｕ（Ⅱ）、Ｃｏ（Ⅱ）Ｃｄ（Ⅱ）Ｍｎ（Ⅱ）基本上不被萃取，从而实现了Ｆｅ（Ⅱ）与Ｃｕ（Ⅱ）Ｃｏ（Ⅱ）Ｃｄ（Ⅱ）Ｍｎ（Ⅱ)及Ａｌ（Ⅲ）与Ｆｅ（Ⅲ）Ｃｏ（Ⅱ）、Ｃｕ（     

铜对氨基酸-固体粒子相互作用的影响

研究了Ｃｕ（Ⅱ）氨基酸（色氨酸、酪氨酸）固体粒子（无定形Ｆｅ（ＯＨ）３、δＭｎＯ２）三者间的相互作用．发现在Ｃｕ（Ⅱ）色氨酸无定形Ｆｅ（ＯＨ）３体系中,色氨酸交换百分率Ｅ（％）ｐＨ曲线为单向上升的峰形．而在Ｃｕ（Ⅱ）酪氨酸δＭｎＯ２体系中,其Ｅ（％）ｐＨ曲线为一种新型的“Ｓ型”与“反Ｓ型”曲线的复合曲线．证实在上述两体系中均有Ⅰ型三元表面络合物生成．     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.