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1.
本文对四极磁透镜的磁场分布和电子的输运问题进行了研究和计算。文中阐述了四极磁透镜边缘场的三种处理方法,用这三种方法计算了透镜的输运矩阵。相互比较表明,四极磁透镜的边缘场采用传统的直角边近似就可以很好地解决问题。 相似文献
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从圆柱坐标系下的Borgnis位函数的齐次标量Helmholtz方程出发,引入慢波驻波概念及其场 表达式,利用Borgnis位函数的边界条件及相邻子区公共界面上的场匹配条件,导出了整腔 结尾的谐振腔链内角向均匀TM模的色散关系及场分布的解析表达式.运用该解析法对实际器 件——四腔渡越管振荡器进行了求解,求得的谐振频率与实验中测得的微波频率一致,求得 的场分布与数值法得到的场分布十分符合.
关键词:
谐振腔链
色散关系
场分布
解析法 相似文献
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本文根据超短沟道MOSFET的工作原理, 在绝缘栅和空间电荷区引入两个矩形源, 提出了亚阈值下电势二维分布的定解问题. 通过半解析法和谱方法相结合, 首次得到了该定解问题的二维半解析解, 解的结果是一个特殊函数, 为无穷级数表达式. 该模型的优点是避免了数值分析时的方程离散化, 表达式不含适配参数、运算量小、精度与数值解的精度相同, 可直接用于电路模拟程序. 文中计算了沟道长度是45—22 nm的MOSFET电势、表面势和阈值电压. 结果表明, 新模型与Medici数值分析结果相同.
关键词:
半解析法
电势
阈值电压
MOSFET 相似文献
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介绍了北京大学分离作用射频四极场(RFQ)加速器的结构特点,包括膜片式电极、支撑环式电极支撑系统、水冷系统、调谐系统及其工艺实现;介绍了基于该分离作用RFQ加速腔进行的调谐测试、高功率实验和束流实验。结果表明:调谐系统的频率调节范围及品质因数完全满足实验要求;分离作用RFQ加速腔的输入功率可以达到33 kW以上,满足高功率下稳定运行的条件;在束流实验中,把1.03 MeV的O+入射束流加速到1.65 MeV,半高宽能散小于3%。加速器结构满足物理设计要求,加速系统运行稳定。 相似文献
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介绍了北京大学分离作用射频四极场(RFQ)加速器的结构特点,包括膜片式电极、支撑环式电极支撑系统、水冷系统、调谐系统及其工艺实现;介绍了基于该分离作用RFQ加速腔进行的调谐测试、高功率实验和束流实验。结果表明:调谐系统的频率调节范围及品质因数完全满足实验要求;分离作用RFQ加速腔的输入功率可以达到33 kW以上,满足高功率下稳定运行的条件;在束流实验中,把1.03 MeV的O+入射束流加速到1.65 MeV,半高宽能散小于3%。加速器结构满足物理设计要求,加速系统运行稳定。 相似文献
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直接从薄圆板的控制微分方程出发,在空间域采用DQ法在时间域取级数,采用时域配点得到求位移场全部待定参数的线性方程组,解一次方程组即得全域的响应位移场。 相似文献
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主要针对二维问题,基于卷积型变分原理,提出了求解瞬态热传导问题的半解析法,该方法在空间域内作分区域插值离散,在时间域上采用解析函数。 相似文献
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考虑到GaAs具有受热分解的特性,采用热传导理论和半解析法研究了波长532nm的毫秒量级长脉冲激光致GaAs的表面热分解损伤.首先,建立了激光辐照GaAs的二维轴对称瞬态温度场及表面热分解损伤阈值的计算模型,模拟了吸收率不同时,GaAs的瞬态温度场分布及热分解损伤阈值.计算结果表明:较高的吸收率引起GaAs表面的温升较高,但所需的热分解损伤阈值较低;增加作用激光能量密度,GaAs表面发生热分解损伤随之提前.本文研究结果对激光与GaAs相互作用及其损伤机理的研究具有指导意义和实用价值. 相似文献
11.
Yee Yee Oo K. N. Nagendra Sharath Ananthamurthy Swarnamala Sirsi R. Vijayashankar G. Ramachandran 《Journal of Quantitative Spectroscopy & Radiative Transfer》2005,90(3-4):343-366
In continuation of our earlier investigation (referred to hereafter as part I) where we considered the mathematically simple case of magnetic field orientation along the Z-axis of the principal axes frame (PAF) of the electric quadrupole field, we take up here the general problem of arbitrary orientation of the magnetic field with respect to the PAF, and investigate the nature of polarized line spectra of an atom making a transition from an upper level with spin Ju to a lower level with spin Jl. Explicit formulae for the emitted Stokes parameters are obtained and we discuss their physical significance by computing numerically the cases of transitions Ju=1→Jl=0 and
. Specific features or signatures of the polarized line spectra are discussed as functions of the relevant physical parameters. The Stokes parameters are also analyzed in terms of the Zeeman term contributions and the cross-term contributions (which arise due to quantum interference). 相似文献
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Yee Yee Oo Sharath Ananthamurthy G. Ramachandran 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,84(1):35-64
The polarization of emission lines formed in a medium immersed in external electric and magnetic fields is studied. The electric field is assumed to be quadrupolar in nature, while the magnetic field is uniform. We show that the quadrupole electric field produces line splitting which is characteristically different from the Zeeman effect. While the line components emitted along the quantization axis are circularly polarized in Zeeman effect, they are, in contrast, linearly polarized in the case of a pure quadrupole electric field. The emission perpendicular to the quantization axis produces three linearly polarized components in Zeeman effect, whereas only two linearly polarized components are observed in the case of quadrupole electric fields. Lack of azimuthal symmetry in the quadrupole electric field leads to polarized line components which appear quite differently for different azimuthal angles of the line of sight. 相似文献
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The quadrupole interaction (QI) of99Ru as a dilute impurity in Zn, Cd and Sn lattices was studied by using time differential perturbed angular correlation technique.
The electric field gradients calculated from the measured quadrupole interaction frequencies at room temperature are 5.14
× 1017 volts/cm2 for99RuZn, 4.58 × 1017 volts/cm2 for99RuCd and 2.87 × 1099 volts/cm2 for99RuSn. The temperature dependence of the QI studied in the case99RuZn is similar to that of117InZn. 相似文献
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We study the qualitative dynamical behaviour of a phantom field minimally coupled to gravity, with an arbitrary self-interacting
potential. We show that the dynamics of this system is surprisingly simple, independently of the form of the potential. Periodic
or oscillatory behaviour of the scale factor or periodic behaviour of the scalar field is not possible. We characterize all
the possible asymptotic behaviours of the dynamical variables. 相似文献
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利用物理光学法计算了高功率微波在建筑物内的耦合场分布。根据建筑物墙壁和窗户的透射率可以得到墙壁内侧的透射场,将它代入到矢量衍射公式中直接计算出在整个建筑物内的透射场;根据建筑物地面的反射率得到地板表面的反射场,将它代入到矢量衍射公式中可计算出整个建筑物内的反射场;对透射场与反射场进行矢量相加,得到叠加场。将本文方法得到的场分布情况和时域有限差分法得到的场分布进行比较,二者结果一致。物理光学法的优点在于其物理图像清晰,计算量小,计算速度快,适合应用在大型建筑物内部耦合场分布计算上。 相似文献
16.
A quadrupole ion trap consisting of electrode structures symmetric about z-axis is an important tool for conducting several precision experiments. In practice the field inside the trap does not remain
purely quadrupolar, and can be calculated using numerical methods. We have used boundary element method to calculate the potential
inside the truncated as well as symmetrically misaligned quadrupolar ion trap. The calculated potential values are fitted
to multipole expansion and the weights of multipole moments have been evaluated by minimizing the least square deviation.
The higher-order multipole contribution in the fabricated hyperbolic electrodes due to truncation and machining imperfections
is discussed. Non-linear effects arising due to the superposition of octupole moment manifest as anharmonic oscillations of
trapped ions in the non-ideal Paul trap. Theoretical simulations of non-linear effects have been carried out.
相似文献
17.
We present a new solution of the Einstein-scalar field system with minimally coupled massless scalar field and nonzero cosmological
constant. The field equations are satisfied on both the four dimensional space and a r = const. three dimensional slice. 相似文献
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An effective potential method for the calculation of hydrogen molecule ion energy in a strong magnetic field 下载免费PDF全文
Using the adiabatic approximation and adiabatic variational approximation with an effective potential, the total energies and the equilibrium internuclear separations of H2+ ion in states σg, πu, δg, φu, γg, ηu in strong magnetic fields have been calculated. Our results reproduced those obtained by Vincke and Baye (Vincke M and Baye D 1985 J. Phys. B: At. Mol. Phys. 18 167), which are considered the most reliable. We found a basic function with better convergence than the Landau functions. 相似文献
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采用简亚模型势函数方法,在ab initio水平上计算了H2O和H2S的分子内价值标和简正内坐标的谐性力学数矩阵对角工根据这两个坐丝毫宰的关系导出了谐性力常数矩阵的其它对角和非对角元。由于避免了三格点的ab inition计算拟合,因此计算量较少。由此计算出的分子谐振动频率与实验 令人满意的。还在简正内坐标的简单价力场近似下,计算了力常数和谐振频率。 相似文献