超磁致伸缩执行器位移测试系统的误差分析

超磁致伸缩执行器位移测试系统是其性能研究的基础。为提高测试数据的准确性,以常用超磁致伸缩执行器位移测试系统为基础,给出了测试系统的误差来源,建立了温升、电源、测量、采集等因素的误差模型以及多因素影响下的误差合成模型。实验与计算结果表明:所设计超磁致伸缩执行器在输出位移为18μm时,位移采集、超磁致伸缩执行器驱动与温升造成的相对误差分别为0.56%、2.83%、3.28%,各因素合成后的相对误差为4.37%。     

Preparation and giant magnetoresistance of electrodeposited Co-Ag/Ag multilayers

Electrodeposition of Co-Ag/Ag multilayers along with their giant magnetoresistance (GMR) was investigated. The electrodeposition process was optimized for both minimizing the dissolution of the Co layer and achieving a high magnetoresistance. Structural analysis of Co-Ag/Ag deposits revealed that silver has an fcc structure, whereas cobalt crystallizes in the hcp structure. No solid solution of Co and Ag was detected. The X-ray diffraction study did not show any satellite reflection. A GMR of the order of 0.5% and 2% could be observed at room temperature and at 20 K, respectively, with both superparamagnetic and ferromagnetic GMR contributions throughout the temperature range studied.     

超磁致伸缩致动器的磁滞非线性动态模型

超磁致伸缩致动器的输入磁场与输出应变存在着磁滞非线性。为了控制及使用致动器，必须建立其准确的数学模型。该文基于Jiles—Atherton磁滞模型、二次畴转模型、非线性压磁方程和致动器结构动力学原理，建立了超磁致伸缩致动器的磁滞非线性动态模型。应用该模型对致动器的输出应变进行计算，计算结果与实验结果符合较好，验证了模型的正确性和实用性。     

超磁致伸缩电液伺服阀动态仿真

利用超磁致伸缩材料研制的一种新型高响应的电-机转换器取代传统力反馈电液伺服阀力矩马达,同时利用传感器将反馈方式由力反馈改为电反馈从而设计了一种新型超磁致伸缩电液伺服阀,并建立了其数学模型及其动态仿真模型,通过一组原始数据分别对两种电液伺服阀进行了参数设计与仿真.仿真结果分析表明超磁致伸缩电液伺服阀较传统力反馈电液伺服阀具有高频响、高精度等显著优点.     

磁性颗粒膜中注入电流驱动激发实验研究

采用离子束溅射技术制备了Co20Cu80磁性颗粒膜样品,并对它的电阻进行了研究:在低磁场时,dV/dI谱线变化缓慢;当H＞Hs时,在通过点接触注入高密度电流为108A/cm2时dV/dI谱线出现一个峰值.认为该电阻变化是由于在Co20Cu80磁性颗粒膜中零波数自旋波的激发,并用试探性的理论给予了解释.同时还研究了Co20Cu80磁性颗粒膜的巨磁电阻以及在高注入电流和强磁场下的静态电阻.     

Rectifying,giant magnetoresistance,spin-filtering,newgative differential resistance,and switching effects in single-molecule magnet Mn(dmit)2-based molecular device with graphene nanoribbon electrodes

By applying the density functional theory and the nonequilibrium Green’s function formalism, we investigate the spin transport properties of a single-molecule magnet Mn(dmit)₂ sandwiched between two ferromagnetic zigzag-edge graphene nanoribbon electrodes. The results show that the system can present large rectifying, giant magnetoresistance, spin-filtering and negative differential resistance effects with the help of magnetic field modulation. Moreover, an improved switching effect can also be realized by changing the orientation between planes of two dmit ligands. Therefore, the system will provide the possibilities for a multifunctional molecular device design.     

Photonuclear reactions of calcium isotopes calculated with the nuclear shell model

Photoabsorption cross sections in calcium isotopes are investigated theoretically with the most advanced nuclear-structure calculations using the nuclear shell model. We show that the photoabsorption cross sections in ⁴⁸Ca dominated by a giant dipole resonance (GDR) are well reproduced with the shell model and predict that a pygmy dipole resonance (PDR) appears in ⁵²Ca in the low-energy tail of GDR. Excellent agreement with the experiment is achieved due to highly correlated many-body wave functions obtained by treating a huge matrix with the dimension of ∼10¹⁰.     

超磁致伸缩驱动器热输出的抑制与补偿方法

超磁致伸缩驱动器具有输出应变大、响应速度快、低频特性好等特点。已经应用于机床的整体和部件的振动控制实验研究。超磁致伸缩材料的热变形严重影响驱动器的输出精度。文章提出了四种抑制或补偿超磁致伸缩驱动器热位移的方法。     

巨偶极共振参数子库（CENPL．GDP－1）的管理－检索程序系统

中国评价核参数库（ＣＥＮＰＬ）的ＧＤＰ－１子库存贮了用Ｌｏｒｅｎｔｚ曲线符合光核反应数据获取的巨偶极共振参数，建立了它的管理检索程序系统。由于库数据文件中仅存有从５１Ｖ到２３９Ｐｕ共１０２个核素的巨偶极共振参数，程序系统采用直接检索、替代、插值和系统学公式计算等方法可以补充库数据文件的不足。这里描述了它的特点、功能及使用方法。