计算机操作中人体静电放电辐射瞬态电场与磁场的研究

分析了静电放电（ESD）辐射场的偶极子模型。用高采样速率数字示波器和定做的宽带电磁与磁场探头测量了计算机操作中人体静电放电产生的瞬态电场与磁场。用FFT分析了静电放电辐射场的频谱。研究了静民放电辐射场对某电路高频信号的影响。研究结果表明,即使是很低电压（2kV）的静电放电,其辐射近场的电场达几百V/m,磁场可达几十A/m静电放电辐射场的频谱极宽,从数兆赫到数千兆赫。静电放电对高频电路的试验结果表明,若不采取有效的防护措施,人体静电放电辐射电磁场会对电路造成一定的影响,如对集成电路与元器件造成“潜在效应”的损害,对电路造成电磁干扰,甚至损坏电子器件。     

Damping of the domain walls motion in Co-based amorphous ribbons with helical magnetic anisotropy: Part III

The damping of the motion of domain walls of a sandwich domain structure by the eddy currents magnetic fields, the stray fields and the hysteresis friction fields is investigated. The blocking of the motion of domain walls by the eddy currents magnetic fields is discovered.     

Generation of perturbations by means of decoupled equations and their adjoints

It is shown that the procedure introduced by Wald for constructing solutions of a coupled system of linear partial differential equations from the solution of a single equation, based on the concept of the adjoint of a linear partial differential operator, can be extended to equations involving spinor fields, matrix fields and two or more fields. Some results concerning massless spinor fields are presented and the application of the method to linear perturbations of Yang-Mills fields and of Einstein-Maxwell fields is indicated.     

Cartan's contortion as a system of spin-2 and spin-0 fields

In several previous papers the author proposed to consider Cartan's contortion as a gauge field of Lorentz-group mediated by a massless spin-2 fields twin. In this article it is shown that these fields may be accompanied by a further pair of massive or massless spin-0 fields. Unfortunately, the study of the interaction of contortion with a Proca field shows that there is no reasonable macroscopic source generating the contortion. This defect is essential; the contortion mediated by standard fields can hardly exist in nature.     

静电放电电磁脉冲的实验研究

 利用单极子天线对静电放电产生的电磁脉冲进行了实验研究。测量表明, 静电放电电磁脉冲辐射场为脉冲持续时间百纳秒的窄脉冲,但在距离放电源几米以内,其场强很大,典型值可达千伏每米量级, 其频谱主要分布在几十到几百兆赫,典型的频谱上限值可以达到几个吉赫。     

On the vectorial fields with position-independent stochastic behavior

Vectorial fields with position-independent stochastic behavior within a certain region are analyzed. More specifically, we deal with the transverse components of this class of beamlike fields (the longitudinal component assumed to be negligible). The general form of the cross-spectral density tensor (CDT) of these fields is shown. Attention is also focused on the properties of these kinds of fields. Thus, among other characteristics, it is seen that the CDT of these fields can be written as the sum of two CDTs associated, respectively, to a totally polarized field and to an unpolarized field. It is also shown that, for such fields, a Young's interference experiment can always be performed whose fringe visibility is optimized. This behavior has analytically been characterized by means of a certain parameter, valid for general beamlike fields. It is shown that, for the fields studied, this parameter reaches its maximum value.     

Moving average fields, macro-scale response measures, and homogenizing micro-scale variation

There are two critical issues when deriving a macro-scale prediction model starting from a more complete, underlying model. The first is the precise relationship of the fields predicted by the more complete model and the fields predicted by the macro-scale model. The second is the manner of solving a closure problem that is invariably encountered in all such derivations. The understanding that moving averages of the fields predicted by the more complete model are the fields predicted by the macro-scale model is challenged on the grounds that accomplishing a moving average does not eliminate micro-scale variation, it only appears to do so in one representation of the moving average field. The solution of a closure problem by assumption is challenged on the grounds that the most common assumptions are demonstrably invalid, even while leading to prediction models that can provide reasonable estimates of the macro-scale response in some scenarios. In presenting the challenges, it is further shown how a multiresolution analysis by an orthogonal wavelet system provides a framework for both precisely defining macro-scale response fields, i.e., fields from which all micro-scale variation has been eliminated, and presenting a formally exact solution for a precisely described closure problem.     

螺旋带行波管耦合磁导纳的计算

 通过对螺旋带行波管带上表面电流的Chebyshev展开,得出了色散关系,求出了电场分量和磁场分量的表达式,进而求得了耦合阻抗和耦合磁导纳。计算并分析了一个典型结构的纵向电磁场分量,由这些分量得出的耦合阻抗与Chernin等的结果有很好的一致性,说明了电场表达式的有效性。场表达式可应用于３维行波管CAD的程序编写,耦合磁导纳的计算程序更是行波管CAD不可缺少的部分。     

Propagation of electric fields induced by optical phonons in semiconductor heterostructures

The penetration of electric fields accompanying long-wavelength optical phonos from one region of a semiconductor heterostructure to another is investigated. It is proposed to determine the penetration depth of such fields from the relaxation caused by these fields in quantum dots. By the example of a cylindrical Ge quantum dot embedded in a GaP/GaAs heterostructure, it is shown that the electric fields induced by longitudinal optical phonons can penetrate through the interface between semiconductors at distances of about 100 nm.     

Second Quantization of the Stueckelberg Relativistic Quantum Theory and Associated Gauge Fields

The gauge compensation fields induced by the differential operators of the Stueckelberg-Schrödinger equation are discussed, as well as the relation between these fields and the standard Maxwell fields; An action is constructed and the second quantization of the fields carried out using a constraint procedure. The properties of the second quantized matter fields are discussed.     

Heat source reconstruction from noisy temperature fields using an optimised derivative Gaussian filter

The aim of this paper is to present a post-processing technique based on a derivative Gaussian filter to reconstruct heat source fields from temperature fields measured by infrared thermography. Heat sources can be deduced from temperature variations thanks to the heat diffusion equation. Filtering and differentiating are key-issues which are closely related here because the temperature fields which are processed are unavoidably noisy. We focus here only on the diffusion term because it is the most difficult term to estimate in the procedure, the reason being that it involves spatial second derivatives (a Laplacian for isotropic materials). This quantity can be reasonably estimated using a convolution of the temperature variation fields with second derivatives of a Gaussian function. The study is first based on synthetic temperature variation fields corrupted by added noise. The filter is optimised in order to reconstruct at best the heat source fields. The influence of both the dimension and the level of a localised heat source is discussed. Obtained results are also compared with another type of processing based on an averaging filter. The second part of this study presents an application to experimental temperature fields measured with an infrared camera on a thin plate in aluminium alloy. Heat sources are generated with an electric heating patch glued on the specimen surface. Heat source fields reconstructed from measured temperature fields are compared with the imposed heat sources. Obtained results illustrate the relevancy of the derivative Gaussian filter to reliably extract heat sources from noisy temperature fields for the experimental thermomechanics of materials.     

Spinors and multivectors as a unified tool for spacetime geometry and for elementary particle physics

From the definition of spinors as the minimal left (right) modules of multivectors (that is, of vectors and their outer products), we can construct a unified mathematical approach for the study of matter and its interaction fields, which are either defined as fields in the geometrical spacetime or considered as generators of the physical spacetime. It is also shown how matter and interaction fields can be represented either by spinor fields or by multivector fields, both types of fields carrying the same information as the traditional corresponding spinors, vectors, or tensors. Geometry is more transparent in one representation (multivector form), and physics is more obvious in the spinor representation. Our theory provides a unified and totally self-consistent representation of quarks (barions), leptons, and all their known interactions.     

Coherent Coupling between Microwave and Optical Fields via Cold Atoms

We demonstrate a long-coherent-time coupling between microwave and optical fields through cold atomic ensembles.The phase information of the microwave field is stored in a coherent superposition state of a cold atomic ensemble and is then read out by two optical fields after 12 ms.A similar operation of mapping the phase of optical fields into a cold atomic ensemble and then retrieving by microwave is also demonstrated.These studies demonstrate that long-coherent-time cold atomic ensembles could resonantly couple with microwave and optical fields simultaneously,which paves the way for realizing high-efficiency,high-bandwidth,and noiseless atomic q uant um converters.     

Pauli equation for a particle in metric and electromagnetic fields

A Pauli theory (Pauli equation and definition of probability current and density) for a particle in weak metric and arbitrary electromagnetic fields is treated. To formulate non-relativistic quantum mechanical problems in arbitrary electromagnetic fields and weak metrics (non-inertial systems, gravitational fields which are distant fields of arbitrary distribution of masses, gravitational waves) it is not necessary to make use of the general-relativistic Dirac equation. Close analogies to the known Pauli theory with electromagnetic fields exist. For different metric fields the corresponding Hamiltonians are given. For quantum systems (H-atoms) which are disturbed by a homogeneous gravitational field and a gravitational wave the resulting shift of energy levels and the transition probability is calculated.     

Spin Axioms in Different Geometries of Relativistic Continuum Physics

The 24 components of the relativistic spin tensor consist of 3 + 3 basic spin fields and 9 + 9 constitutive fields. Empirically only three basic spin fields and nine constitutive fields are known. This empirem can be expressed by two spin axioms, one of them denying purely relativistic spin fields, and the other one relating the three additional basic fields and the nine additional constitutive fields to the known (and measurable) ones. This identification by the spin axioms is material-independent and does not mix basic spin fields with constitutive properties. The approaches to the Weyssenhoff fluid and the Dirac-electron fluid found in literature are discussed with regard to these spin axioms. The conjecture is formulated, that another reduction from six to three basic spin fields which does not obey the spin axioms introduces special material properties by not allowed mixing of constitutive and basic fields.     

超强频率梳激光场驱动下多光子共振谐波辐射的相位突变研究

本文从理论上研究了在双色频率梳激光场驱动下多光子谐波辐射光谱中的相位突变现象。我们利用Floquet理论非微扰地模拟了频率梳激光场与原子分子等量子系统的相互作用过程。谐波辐射信号是多光子偶极跃迁相干叠加的结果,通过调节频率梳激光场间的相对相位,可以相干地控制谐波辐射信号的强度。通过对谐波信号进行傅里叶变换,可以提取不同跃迁路径的相对相位信息。我们通过改变频率梳组激光场的强度和频率组分实现多光子跃迁频率,让其跨越共振跃迁频率时,谐波相位会发生突变。从而可以观测超强激光场驱动下量子系统共振跃迁频率的斯塔克能移。     

Evaluation of the magnetic dipolar fields from layered systems on atomic scale

Exact analytical expressions for the magnetic dipolar fields produced by a plane square lattice with localized magnetic moments are derived. Basing on these expressions surface roughness of a magnetic thin film is considered. Influence of the bipolar fields on the surface anisotropy and hyperfine fields is discussed.     

Entanglement in a two-boson coupled system

A model for two nondegenerate cavity fields coupled through a reservoir is considered. Such a model can be employed for the study of Raman scattering in which the Stokes and anti-Stokes fields indirectly interact via a bath of phonon. An analysis for appearance of quantum entanglement between the fields and evaluation of the entanglement measure depending on initial states of the fields and on a state of the phonon reservoir is given. The text was submitted by the author in English.     

Gravitational scattering of electromagnetic radiation

The scattering of electromagnetic radiation by linearized gravitational fields is studied to second order in a perturbation expansion. The incoming electromagnetic radiation can be of arbitrary multipole structure, and the gravitational fields are also taken to be advanced fields of arbitrary multipole structure. All electromagnetic multipole radiation is found to be scattered by gravitational monopole and time-varying dipole fields. No case has been found, however, in which any electromagnetic multipole radiation is scattered by gravitational fields of quadrupole or higher-order multipole structure. This lack of scattering is established for infinite classes of special cases, and is conjectured to hold in general. The results of the scattering analysis are applied to the case of electromagnetic radiation scattered by a moving mass. It is shown how the mass and velocity may be determined by a knowledge of the incident and scattered radiation.This work was supported in part by the National Aeronautics and Space Administration and the National Science Foundation. It incorporates some of the results of the first author's doctoral dissertation at the University of Pittsburgh.     

Spontaneous emission spectra of a four-level atom in photonic crystals driven by two coherent fields

We investigate the spontaneous emission spectra of a four-level tripod-type atom embedded in a photonic crystal and driven by two coherent fields. It is found that due to the quantum interference caused by two driving fields, the spontaneous emission spectra have different features from the case of only one driving field. The spectra are sensitively dependent on the detuning of the driving fields. A dark line occurs for some particular initial states. By appropriately adjusting the external driving fields, the spectral-line can be narrowed, enhanced or suppressed.