排序方式: 共有87条查询结果,搜索用时 15 毫秒
1.
Pu-Kun Liu Zhong-Hai Yang Shang-Jie Qian Sheng-Gang Liu 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1995,23(2):156-162
Using the Laplace transformation, the kinetic theory of the high-relativistic electron cyclotron maser having a novel open-resonator-the axisymmetrical quasioptical cavity of oblique rotation at arbitrary angle, is carried out within the framework of the linearized Vlasov-Maxwell equations. The beam-wave interaction power, starting current and frequency shift have been derived and numerically calculated. The influence of rotation angle on the beam-wave interaction is also studied. A series of important conclusions obtained reveal the characteristics of this novel quasioptical electron cyclotron maser 相似文献
2.
Ni ZH Kou HZ Zheng L Zhao YH Zhang LF Wang RJ Cui AL Sato O 《Inorganic chemistry》2005,44(13):4728-4736
Two new cyano-bridged heterobinuclear complexes, [Mn(II)(phen)2Cl][Fe(III)(bpb)(CN)2] x 0.5CH3CH2OH x 1.5H2O (1) and [Mn(II)(phen)2Cl][Cr(III)(bpb)(CN)2] x 2H2O (2) [phen = 1,10-phenanthroline; bpb(2-) = 1,2-bis(pyridine-2-carboxamido)benzenate], and four novel azido-bridged Mn(II) dimeric complexes, [Mn2(phen)4(mu(1,1)-N3)2][M(III)(bpb)(CN)2]2 x H2O [M = Fe (3), Cr (4), Co (5)] and [Mn2(phen)4(mu(1,3)-N3)(N3)2]BPh4 x 0.5H2O (6), have been synthesized and characterized by single-crystal X-ray diffraction analysis and magnetic studies. Complexes 1 and 2 comprise [Mn(phen)2Cl]+ and [M(bpb)(CN)2]- units connected by one cyano ligand of [M(bpb)(CN)2]-. Complexes 3-5 are doubly end-on (EO) azido-bridged Mn(II) binuclear complexes with two [M(bpb)(CN)2]- molecules acting as charge-compensating anions. However, the Mn(II) ions in complex 6 are linked by a single end-to-end (EE) azido bridging ligand with one large free BPh4(-) group as the charge-balancing anion. The magnetic coupling between Mn(II) and Fe(III) or Cr(III) in complexes 1 and 2 was found to be antiferromagnetic with J(MnFe) = -2.68(3) cm(-1) and J(MnCr) = -4.55(1) cm(-1) on the basis of the Hamiltonian H = -JS(Mn)S(M) (M = Fe or Cr). The magnetic interactions between two Mn(II) ions in 3-5 are ferromagnetic in nature with the magnetic coupling constants of 1.15(3), 1.05(2), and 1.27(2) cm(-1) (H = -JS(Mn1)S(Mn2)), respectively. The single EE azido-bridged dimeric complex 6 manifests antiferromagnetic interaction with J = -2.29(4) cm(-1) (H = -JS(Mn1)S(Mn2)). Magneto-structural correlationship on the EO azido-bridged Mn(II) dimers has been investigated. 相似文献
3.
A dicyano-containing [Fe(bpb)(CN)2]- building block has been employed for the synthesis of cyano-bridged heterometallic Ni(II)-Fe(III) complexes. The presence of steric bpb(2-) ligand around the iron ion results in the formation of low-dimensional species: five are neutral NiFe2 trimers and three are one-dimensional (1D). The structure of the 1D complexes consists of alternating [NiL]2+ and [Fe(bpb)(CN)2]- generating a cyano-bridged cationic polymeric chain and the perchlorate as the counteranion. In all complexes, the coordination geometry of the nickel ions is approximately octahedral with the cyano nitrogen atoms at the trans positions. Magnetic studies of seven complexes show the presence of ferromagnetic interaction between the metal ions through the cyano bridges. Variable temperature magnetic susceptibility investigations of the trimeric complexes yield the following J(NiFe) values (based on the spin exchange Hamiltonian H = -2J(NiFe) S(Ni) (S(Fe(1)) + S(Fe(2))): J(NiFe) = 6.40(5), 7.8(1), 8.9(2), and 6.03(4) cm(-1), respectively. The study of the magneto-structural correlation reveals that the cyanide-bridging bond angle is related to the strength of magnetic exchange coupling: the larger the Ni-N[triple bond]C bond angle, the stronger the Ni- - -Fe magnetic interaction. One 1D complex exhibits long-range antiferromagnetic ordering with T(N) = 3.5 K. Below T(N) (1.82 K), a metamagnetic behavior was observed with the critical field of approximately 6 kOe. The present research shows that the [Fe(bpb)(CN)2]- building block is a good candidate for the construction of low-dimensional magnetic materials. 相似文献
4.
基于构筑单元K2[Fe(1-CH3im)(CN)5]和[Cu(cyclam)](ClO4)2,合成了一个氰根桥联FeⅢ-CuⅡ中性一维化合物{[Fe(1-CH3im)(CN)4(μ-CN)Cu(cyclam)]·H2O}n(1-CH3im=1-甲基咪唑;cyclam=1,4,8,11-四氮杂环十四烷)(1),并通过X-射线单晶分析表征其结构特征。结果表明:化合物(1)是由氰根桥联的杂金属组成的聚合物,其结构属于三斜晶系,P1空间群,a=0.832 56(17)nm,b=0.899 38(18)nm,c=0.998 3(2)nm,α=111.94(3)°,β=95.06(3)°,γ=116.90(3)°,V=0.587 7(2)nm3,Z=1,Dc=1.554 g·cm-3,μ=1.558 mm-1,F(000)=286,R1=0.051 9,wR2=0.135 3。磁性研究表明:配合物1中CuⅡ和低自旋的FeⅢ离子之间存在弱的铁磁耦合作用。 相似文献
5.
基于一系列二氰根铬与[Cu(cyclam)](ClO4)2反应合成了3个氰根桥联CrⅢ-CuⅡ-CrⅢ三核配合物[Cu(cyclam)][Cr(bpmb)(CN)2]2·4H2O(1)(cyclam=1,4,8,11-四氮杂环十四,bpmb2-=1,2-二(2-吡啶甲酰胺基)-4-甲基苯),[Cu(cyclam)][Cr(bpdmb)(CN)2]2(2)(bpdmb2-=1,2-二(2-吡啶甲酰胺基)-4,5-二甲基苯)和[Cu(cyclam)][Cr(bpClb)(CN)2]2·4H2O(3)(bpClb2-=1,2-二(2-吡啶甲酰胺基)-4-氯苯)。单晶衍射结果表明:3个化合物是结构类似的中性三核配合物,均含有氰根桥联的Cr(Ⅲ)-CN-Cu(Ⅱ)-NC-Cr(Ⅲ)连接;磁性研究表明:氰根桥在CrⅢ和CuⅡ离子间传递弱的铁磁耦合作用,基于自旋哈密顿算符Ĥ=-2JCrCuŜCu(ŜCr1+ŜCr2)拟合得到它们的磁耦合常数分别是JCrCu=1.53(2) cm-1(1),0.45(1) cm-1(2)和0.73(2) cm-1(3)。 相似文献
6.
7.
借助于Tersoff势函数和分子动力学模拟技术研究了室温下500eV的能量粒子硼(4个)和氮(8个)共掺入金刚石晶体中所引起的损伤区域内晶体微细观结构的变化特征以及后续加热退火晶体结构的演变特征.结果表明:随着掺入原子数目的增加,受影响的区域范围渐渐增大,12个粒子全部注入金刚石晶体后局部影响区域的半径达0.68nm,损伤区域中心的三配位原子数增加而四配位数原子数量减少.加热退火过程中损伤中心区域的原子发生扩散,部分原子的扩散距离达到4个晶格间距.加热退火使损伤区域中心原子间的平均键长趋于金刚石结构的键长.退火后薄膜中注入的杂质原子向表面扩散引起应力分布产生变化,杂质原子经过一系列的扩散过程能够到达空位的位置,减少薄膜中空位数量,减小晶格畸变程度,原子向表面扩散引起应力产生重新分布,薄膜中应力峰值的峰位向薄膜表面发生移动,局部应力集中程度降低.通过不同退火温度的比较发现低温下退火(800℃)更有利于空位的运动和晶格损伤的恢复从而提高晶格质量.
关键词:
金刚石共掺杂
分子动力学
退火 相似文献
8.
9.
10.
行波管再生反馈振荡器是一种新型太赫兹源器件.基于560GHz折叠波导慢波结构,对此类器件的工作原理与物理模型进行分析阐述.采用非线性互作用模型对行波管再生反馈振荡器进行详细振荡过程模拟.模拟结果显示,在550—600GHz频率下可以获得稳态振荡频率,并在560GHz处获得最大单频输出功率.结果同时表明,振荡频率随电子注电压发生跳变现象,并简要分析了其产生原因. 相似文献