Morphologies and magnetic properties of FeCo nanoparticles modulated by changing the types of ligands of Co

A new way of preparing FeCo nanoparticles has been developed using the co-precipitation technique based on the appropriate Co precursors of different types of ligands. These new precursors have been prepared by the reaction of cobalt acetate with three various coordination compositions for forming cobalt complex types. This technique provides proper control on nanoparticle size distribution after annealing to 500 °C. The variation of the magnetic properties with the type of ligands of Co can arise from the changes of the microstructures and crystalline anisotropies. Maximum coercivity values of 480 Oe were obtained. It is found that the precursors with special structures can prevent from agglomeration without presence of any surfactants.     

He-O2高气压下电容耦合辉光放电数值分析

采用一维的等离子体流体力学模型研究了氦气-氧气高气压下电容耦合放电过程。分别给出了间隙为1.6,2.4和3.2 mm时外加电压的有效值与放电电流有效值特征曲线,并与已有的实验数据作对比,结果表明计算得到的电压-电流特征曲线与实验数据符合得很好。研究发现：氦气-氧气高气压下电容耦合放电过程中荷质比较大的离子在鞘层中的分布随着外电场的变化而变化,而荷质比较小的粒子在整个放电区域基本不随外电场变化而变化;同时杂质形成正负离子在主等离子体区域两端出现了峰值。     

Pd-Catalyzed enantioselective synthesis of 2-methyl-3-methyleneindoline

A Pd-catalyzed enantioselective synthesis of 2-methyl-3-methyleneindoline in up to 89% yield and 84% ee from racemic vinyl benzoxazinanones has been developed with the help of(R,R)-BenzP*ligand.Mechanism studies support the formation of palladacyclobutane as the key intermediate via C2 attack to π-allyl Pd complex.The β-hydride elimination provides a new reaction pathway for the palladacyclobutane.