Pulse Coupling Research Articles

On-line PD detection and localization in cross-bonded HV cable systems

This paper addresses the detection and localization of partial discharge (PD) in crossbonded (CB) high voltage (HV) cables. A great deal has been published in recent years on PD based cable insulation condition monitoring, diagnostics and localization in medium voltage (MV) and high voltage (HV) cables. The topic of pulse propagation and PD source localization in CB HV cable systems has yet to be significantly investigated. The main challenge to PD monitoring of CB HV cables is as a result of the interconnectedness of the sheaths of the three single phase cables. The cross-bonding of the sheaths makes it difficult to localize which of the three phases a PD signal has emanated from. Co-axial cables are used to connect cable sheaths to cable link boxes, for ease of installation and protection against moisture. A second challenge is, therefore, the coupling effect when a PD pulse propagates in HV cable joints and the co-axial cables, making PD detection and localization more complex. The paper presents experimental investigations into PD pulse coupling between the cable center conductor and the sheath and the behavior of PD pulse propagation in CB HV cables. It proposes a model to describe PD pulse propagation in a CB HV cable system to allow monitoring and localization, and also presents the knowledge rules required for PD localization in CB HV cable systems.

Simulation Study on Coupling Effect under HEMP of Shielding Control Box

The coupling effect under HEMP calculation model of the shielding control box is established with the CST software. The shielding effectiveness of the shielding control box with different incidence directions of HEMP were studied on, and the field distribution of the shielding control box was analyzed. The results show that incidence direction of HEMP in the depth direction of the gap and perpendicular to the long side of the gap can provide the worst electromagnetic pulse protection of shielding control box. The coupling field of the complex system box has resonant characters. The gap filled with conductive rubber can effectively reduce the coupling of electromagnetic energy pulse.

Experimental study of air-core dielectric tube at terahertz frequencies

In this paper, an experimental study of air-core dielectric tube waveguide is proposed at terahertz frequencies. By using the THz time domain measure system, the terahertz dispersion characteristics, loss characteristic and energy focusing characteristic of air-core single-layer and dual-layer dielectric tube are obtained. The results show that this type of air-core dielectric tube can realize low dispersion characteristics. Due to the difference of refractive index between two dielectric materials, stronger energy focusing can be achieved in air-core dual-layer dielectric tube. After the coupling of the THz pulse using the dual-layer dielectric tube waveguide, the THz pulse increased 2.4 times compared with the single-layer dielectric tube waveguide at 1.5THz.

Three-level superadiabatic quantum driving

The superadiabatic quantum driving, producing a perfect adiabatic transfer on a given Hamiltonian by introducing an additional Hamiltonian, is theoretically analyzed for transfers within a three-level system. Our starting point is the stimulated Raman adiabatic passage, realized through different schemes of laser pulses. We determine the superadiabatic correction for each scheme. The fidelity, robustness, and transfer time of all the superadiabatic transfer schemes are discussed. We derive that all superadiabatic corrections are based on a π- (or near-π)-area pulse coupling between the initial and final states. The benefits in the protocol robustness overcome the difficulties associated to the actual implementation of the three-level superadiabatic transfer.1 MoreReceived 1 February 2014DOI:https://doi.org/10.1103/PhysRevA.89.033419©2014 American Physical Society

Coherent detection of metal-metal terahertz quantum cascade lasers with improved emission characteristics

Coherent detection of emission from quantum cascade lasers with metal-metal waveguides is demonstrated through free-space coupling of a THz pulse to the sub-wavelength waveguide. We implement a simple, monolithic planar horn antenna design on the metal-metal waveguide that reduces the impedance mis-match to the waveguide. The resulting devices show up to 10 times more directed output power than conventional metal-metal waveguides. This enhanced coupling to free-space allows a more efficient injection of broad-band THz pulses into the waveguide. Through this, we are able to seed the laser emission and coherently detect the laser emission by electro-optic sampling.

Characteristics of Electromagnetic Coupling with A Wire through Shielding Enclosure

The paper presents a numerical method based on Finite Difference Time Domain (FDTD) in both frequency and time domain for modeling the coupling of an incident electromagnetic pulse(EMP) with a conducting wire through a metallic shielding enclosure with a small aperture. Simulation and analysis are done by radius, length, and number of the wires, the incidence angle of EMP and the polaration angle of electric field in consideration. The simulation result shows that interference of the electromagnetic coupling into the shielding enclosure can be affected in different degrees by above factors. At low frequency, the larger the leakage length, the radius or the number of the wire penetrated into the cavity, the more interference is coupled into the shielding cavity from electromagnetic field. Also, the smaller the incident direction angle of propagation of the electromagnetic pulse or the polarization direction angle of the incident electric field, the more easily the electromagnetic interference is coupled into the cavity. DOI : http://dx.doi.org/10.11591/telkomnika.v12i2.3984

Numerical Analysis of the Effects Caused by Ground Reflection on Aperture Coupling

In order to analyze the influence of the near-ground reflection on aperture coupling, a full-scale model of metal shelter with a lossy ground was constructed. The rules of aperture coupling of the High-altitude Electromagnetic Pulse were researched, while the angle of incidence, the conductance and relative permittivity of the ground were changed respectively. Then the strength of electric field inside the shelter was computed and compared when the shelter was above on different topography. Studies show that the coupling electromagnetic energy strengthen with the incident angle of plane wave increasing. When the conductance and relative permittivity of the ground gain, the main crest of the electric field substantially keeps constant, while the second crest increases dramatically. Sea surface has the strongest reflection of electromagnetic pulse, followed by sand land, then the mud land. The reflection of wet land is much stronger than dry land.

High-capacity and security molecular capsule transporters

Multiwavelength optical capsules can be generated and controlled by using soliton/Gaussian pulses within a nonlinear device system known as a “PANDA” ring circuit and system. The security of molecule/drug transportation can be formed by the strong coupling of soliton-like pulse, where the high-capacity optical capsules can be formed using the multiwavelength solitons, which can be a good advantage and combination of drug delivery to the required targets. Moreover, the multiple access of drug delivery can be formed using the optical networks, which allows the use of various drug molecules with variety of diagnosis and therapeutic applications.

Enhanced discharge of high power pulsed magnetron sputtering coupling with high voltage

Plasma source ion implantation and deposition, as an effective technology to produce functional coatings with high adhesion and density, possesses the wide application prospect, especially in the deposition of coatings that work in high loading service conditions. The key component of this technology is the metal plasma source, which is now based on pulsed cathodic arc with complex source structure and magnetic filtration because of the macro-droplets in the ion flux. In this paper, we present another metal plasma source, high power pulsed magnetron sputtering (HPPMS), and investigate the discharge characteristics at different coupling high-voltages by optical emission spectroscopy. The results show that significant improvements are found in the discharge target current and main particles in the plasma. The improvement in gas discharge by the coupling high-voltage is greater than in metal discharge which could increase obviously in the self-sputtering stage with higher target voltage discharge. Last but not least, in this paper we discuss the discharge enhancing mechanism of coupling high-voltage. It is found that the self-excited glow discharge of coupling high-voltage, the hollow-cathodic effect induced by face-to-face negative voltages of HPPMS and coupling high-voltage, and the enhanced ambipolar diffusion of the coupling high-voltage can all play a considerable role in HPPMS discharge.

电磁脉冲耦合效应的等效源建模及应用

电磁脉冲耦合效应的等效源建模及应用

Characteristics of Electromagnetic Pulse Coupling into Annular Apertures

Electromagnetic pulse (EMP) coupling into the annular apertures can disturb or damage much electronic equipment. To enhance electronic system’s capability of anti-electromagnetic interference, the finite difference time domain method (FDTD) was employed to study the characteristics of electromagnetic pulse coupling into the cavity enclosures with annular apertures. The coupling characteristics of annular apertures with different shapes (rectangle, square and circle) were discussed. It shows that, in the case of the same aperture area, the coupling energy of electromagnetic pulse into the circular annular aperture is smaller than that into the rectangular and the square ones. To the rectangular annular aperture, while the polarization direction of the incident electromagnetic pulse is perpendicular to the long side of the rectangular annular aperture, the coupling energy is larger when the aspect ratio of the rectangular annular aperture is larger. The coupling effect of incident pulse with short pulse width is obviously better than the one with longer pulse width. The resonance phenomenon of the coupled waveform occurs in the cavity. DOI: http://dx.doi.org/10.11591/telkomnika.v11i11.3544

Theoretical study of air-core dielectric tube at terahertz frequencies

In this paper, the terahertz propagation characteristics of air-core dielectric tube waveguide, including air-core single-layer dielectric tube and dual-layer dielectric tube, are investigated by theoretical calculation. Due to the difference of refractive index between two polymer materials, stronger energy coupling can be achieved in dual-layer dielectric tube, and the field confinement is enhanced further. After the coupling of the THz pulse using the dual-layer dielectric tube, the THz pulse increased 5.2 times compared with the single-layer dielectric tube at 1THz. The ratio of power in polymers, air core and air cladding to the total power versus radiation frequency is presented, respectively. The dispersion and loss characteristic of the air-core dielectric tube is also demonstrated by using experimental method.

Generation of periodic structures on SiC upon laser plasma XUV/NIR radiations

AbstractSurface periodic structures are generated upon irradiation of a silicon carbide (SiC) thin film by the plasma produced by 40 fs pulses from a Ti:Sapphire laser focused onto a thick low density polyethylene (LDPE) foil facing the SiC film. Independently of the number of laser pulses applied, these structures, with average regular periodicity of 710 nm, are evident throughout all irradiated areas. We attribute their formation to the efficient coupling of the unfocused femtosecond laser pulse with the incoherent extreme ultraviolet component of the laser-generated LDPE plasma.

FDTD 방법을 이용한 간단한 건물 구조의 광대역 차폐 효과에 관한 연구

본 논문은 유한 차분 시간 영역(FDTD: Finite-Difference Time-Domain)법을 이용하여 간단한 건물 구조의 광대역 복사성 펄스 결합에 관한 연구를 수행하였다. 이를 위해 건물을 콘크리트와 유리로 구성하였으며, 각 물질의 전기적 특성을 수치적으로 모델링하였다. 본 논문에서는 본 연구팀에서 개발한 분산 FDTD 알고리즘을 이용하여 건물의 전자파 특성 해석을 수행하고, 건물 구조에 따른 차폐 효과를 50 MHz~1 GHz 대역에서 분석하였다. We perform a wideband radiated pulse coupling analysis of simple building structures using the finite-deference time-domain(FDTD) method. Toward this purpose, the building structures composed of concrete and window materials are assumed and we numerically model the electrical properties of each material. In this work, we apply a dispersive FDTD algorithm for the electromagnetic analysis of building structures and investigate their shielding effectiveness in the frequency range of 50 MHz to 1 GHz.

Mechanisms that enhance sustainability of p53 pulses.

The tumor suppressor p53 protein shows various dynamic responses depending on the types and extent of cellular stresses. In particular, in response to DNA damage induced by γ-irradiation, cells generate a series of p53 pulses. Recent research has shown the importance of sustaining repeated p53 pulses for recovery from DNA damage. However, far too little attention has been paid to understanding how cells can sustain p53 pulses given the complexities of genetic heterogeneity and intrinsic noise. Here, we explore potential molecular mechanisms that enhance the sustainability of p53 pulses by developing a new mathematical model of the p53 regulatory system. This model can reproduce many experimental results that describe the dynamics of p53 pulses. By simulating the model both deterministically and stochastically, we found three potential mechanisms that improve the sustainability of p53 pulses: 1) the recently identified positive feedback loop between p53 and Rorα allows cells to sustain p53 pulses with high amplitude over a wide range of conditions, 2) intrinsic noise can often prevent the dampening of p53 pulses even after mutations, and 3) coupling of p53 pulses in neighboring cells via cytochrome-c significantly reduces the chance of failure in sustaining p53 pulses in the presence of heterogeneity among cells. Finally, in light of these results, we propose testable experiments that can reveal important mechanisms underlying p53 dynamics.

Electric and magnetic terahertz nonlinearities resolved on the sub-cycle scale

Table-top sources of intense multi-terahertz (THz) pulses have opened the door to studies of extreme nonlinearities in the previously elusive mid- to far-infrared spectral regime. We discuss two concepts of fully coherent coupling of phase-locked THz pulses with condensed matter. The first approach demonstrates two-dimensional multi-THz spectroscopy of the semiconductor material InSb. By phase- and amplitude-sensitive detection of the nonlinear optical response, we are able to separate incoherent pump–probe signals from coherent four-wave mixing and reveal extremely non-perturbative nonlinearities. While this class of interactions is mediated by the electric field component of the THz pulse, the second approach is complementary, as it demonstrates that, alternatively, the magnetic THz field may be exploited to selectively control the spin degree of freedom in antiferromagnetic NiO.

Analytic Iterative Solution of Electromagnetic Pulse Coupling to Multiconductor Transmission Lines

This paper provides an efficient iterative solution in the frequency domain for electromagnetic pulse (EMP) radiated field coupling to multiconductor transmission lines (MTLs) based on distributed analytical representation of the exciting sources and iterative technique originated from waveform relaxation. The method consists of two kinds of iterations, the first is that the incoming EMP wave couples to each conductor while the effects of neighboring conductors were neglected; the second is that each conductor will be not only subject to the illumination of the EMP wave, but also influenced by the virtual sources which are the induced voltages and currents of the neighboring conductors at the previous iteration. The key highlights of the proposed method are that the induced voltage and current at each iteration are considered as the virtual distributed exciting sources for next iteration, and the integrals were solved analytically by the Baum-Liu-Tesche equation, leading to a pretty good efficiency and quick convergence for most real cases. The validation results over a wide range show that the proposed method could efficiently handle EMP coupling to MTLs with a large number of conductors and the accuracy of the solutions is closely related to the number of iterations allowing the flexibility to choose between the accuracy and the time cost.

ChemInform Abstract: Synchronization and Complex Dynamics of Oscillators with Delayed Pulse Coupling.

AbstractReview: 29 refs.

Effect of the laser wavelength: A long story of laser-plasma interaction physics for Inertial Confinement Fusion Teller Medal Lecture

Laser-driven Inertial Confinement Fusion (ICF) relies on the use of high-energy laser beams to compress and ignite a thermonuclear fuel with the ultimate goal of producing energy. Fusion is the holy grail of energy sources-combining abundant fuel with no greenhouse gas emissions, minimal waste products and a scale that can meet mankind's long-term energy demands. The quality and the efficiency of the coupling of the laser beams with the target are an essential step towards the success of laser fusion. A long-term program on laser-plasma interaction physics has been pursued to understand the propagation and the coupling of laser pulses in plasmas for a wide range of parameters. Soon after the laser discovery, the idea to build high-power lasers to drive fusion reactions in a small pellet to produce energy was proposed by Jean Robieux (1). Fusion energy is an attractive, environmentally clean, power source with no greenhouse gases or long-lived radioactive waste materials. An essential step towards ignition is the efficient coupling of the laser beams with the target. During the first picoseconds of the laser pulse irradiating a material, a plasma is produced. The physics of laser- plasma interaction includes the propagation of the beams in this plasma and the processes by which the energy of the electromagnetic wave is given to the plasma. Because of the high energy that must be transferred to the target during the laser pulse, laser intensities are such that non-linear processes are expected. One important parameter for the laser propagation in a plasma is the critical density, which is the maximum electron density in which the electromagnetic wave can propagate. The critical density is inversely proportional to the square of the laser wavelength (0): (nc (cm −3 ) = 1.1 × 10 21 /0(m) 2 ). The energy deposited in the corona is then transferred by conduction in the denser plasma. The main processes of energy deposition or reflection were identified in the seventies. Among them, it was soon demonstrated that collisional absorption, which transfers the laser energy to the bulk of the plasma, was the only useful mechanism for Inertial Confinement Fusion (ICF). Other laser-plasma coupling mechanisms, also named anomalous absorption processes, were shown to be deleterious for inertial fusion because the energy was given to hot electrons. Suprathermal electrons can preheat the fuel and thus be detrimental to efficient compression. Among the non-linear processes are the resonant couplings of the incident laser electromagnetic (EM) wave with the plasma modes, which generate scattered electromagnetic waves (2). So are stimulated Brillouin (SBS) and Raman scattering (SRS), which can be described as the decay of the incident EM wave into a scattered EM wave and an ion-acoustic wave (IAW) or an electron plasma

Synchronization and Complex Dynamics of Oscillators with Delayed Pulse Coupling

Finger on the pulse: A systematic experimental study of pulse-coupled chemical oscillators with delay has confirmed a surprisingly large number of theoretical and mathematical predictions (see the dynamics for a pair of pulse-coupled oscillators; AP=antiphase (AP) and IP=in-phase oscillations, C=complex bursting dynamics, and OS=oscillator suppression). These results have implications for neuroscience and other biological fields.