External Electromagnetic Disturbances Research Articles

Expansion of the functional capacities of electrostatic mirror analyzers for electron spectroscopy

Electron spectroscopy methods are widely used in scientific research and for technological purposes. The main element of spectrometers is an analyzer of charged particle beams. Electrostatic mirror systems are widely used due to their simpler practical realization. At their development two purposes were set: to improve the quality of spatial focusing of charged particles or to increase the value of linear energy dispersion. The objects of the study are electrostatic systems characterized by small sizes, simplicity of stabilization and localization of the working field and its shielding from the external electromagnetic disturbances. From all the known types of energy analyzers, suitable for the analysis of solid surfaces, preference is given to those that have good electron-optical properties, are simple in manufacture and operation. Therefore, spherical and cylindrical mirrors, which have become a basic tool for firms producing spectrometers, have been chosen as the object of study. The work solves the problem of expansion of the functional capacities of these systems by, firstly, combining several research methods in one device; and secondly, by solving specific narrower problems. A photoelectron or Auger spectrometer with an increased scanning area is proposed, where the initial angular opening of the beam 4° after passing a cylindrical mirror is increased to 10°, and the image smearing is reduced to 0.05 %. An Auger-electron spectrometer for analysis of rough surface has been developed, which allows to increase the probing depths by more than 5 times. A double filter type energy analyzer is calculated. Energy resolution was improved to 1.37 % by eliminating potential barrier smearing in low energy filter mode. Previously, the energy resolution was limited to 10 % due to this drawback

Upper bound of overvoltage peak induced in power line network above lossless ground due to radiated electromagnetic disturbances

This paper deals with the assessment of the maximal peak of the overvoltage induced in a power-line network due to the field-to-wire coupling from an external electromagnetic disturbance. A worst-case analysis is here combined with the transmission line model to find the terminal overvoltage, induce by radiated electromagnetic disturbances of constrained energy density and bandlimits. The approach was applied to canonic power line network topologies, from statistic viewpoint, it is demonstrated that dominant coupling can be ascribed to the branch containing the most twisted segments. Accordingly, efforts have been devoted to find analytical solution to overvoltage peak upper bound for the coupling-dominant zigzag branch. In this connection, both versatile implicit solution and approximated explicit expressions of the upper bound are formulated, which reveals the relations between the upper bound of zigzag branch and its segments, quantitively interpreting the effect of segment orientations and length. Finally, numerical simulations corroborate the model validity and suggest that the estimations of upper bound are sufficiently accurate for analyzing practical power line network. This proposed approach will be instructive for power system insulation coordination and protection design.

Joint Angle Estimation Using Accelerometer Arrays and Model-Based Filtering

Measurement of joint angles is an important element for the control of robotic systems and monitoring human gait. This has been traditionally approached through the use of contact sensors, e.g., optical or magnetic encoders, and inertial measurement units (IMUs). IMUs fuse data from accelerometers, gyroscopes, and magnetometers to estimate the orientation of the body. However, microelectromechanical system (MEMS) gyroscopes are prone to drift, and magnetometers are susceptible to electromagnetic interference. In contrast, MEMS accelerometers have stable bias and are resilient to external electromagnetic disturbances. Consequently, an all-accelerometer noncontact sensor can mitigate these problems. In the context of two links connected at a joint, the acceleration at this common point is equivalent irrespective of the coordinate system of either of the links. The research presents the use of an array of two or more accelerometers (noncontact sensors) and the knowledge of the acceleration equivalence at the joint to construct a dynamic model where the states correspond to angular velocities of the joints and the joint angle. The joint angle is estimated using three approaches—analytical, the extended Kalman filter (EKF), and the unscented Kalman filter (UKF). The analytical approach estimates the joint angle, while the model-based filtering approaches (EKF and UKF) also estimate the link angular velocities. Simulations are performed using two to ten accelerometers on each link to compare the performances of the three methods and investigate the placement of accelerometers along the links. The simulation results indicate superior performance of the model-based filtering approaches over the analytical. The analysis also concludes that the best physical placement of the accelerometers is toward the ends of the link for minimizing estimation error. In addition, the lower bound of the estimation error is dictated by the maximum ratio of mean to relative accelerometer length between the two links. The algorithms are experimentally validated using three different accelerometers: ADXL345, ADXL357, and BNO055. Four different canonical movements of slow and fast periodic, ramp, and impulse are examined. The experiment results corroborate the better performance of the model-based filters over the analytical approach.

The kinetic inductance of single-walled carbon nanotube metal type

The results of theoretical studies of the kinetic inductance Lk metallic single-walled carbon nanotube type, taking into account the electron-electron interaction in the approximation of a right circular cylinder are presented. The system under consideration is a cylindrically symmetric potential well with a final height of the wall. As part of the response of the theory of two-dimensional electron gas in the external electromagnetic disturbance obtained in the form of kinetic inductance depending on the nanotube diameter, frequency and intensity of the radiation. Established that Lk value increases with increasing frequency, and decreases with increasing radiation intensity.

Stochastic Propagation Delay Through a CMOS Inverter as a Consequence of Stochastic Power Supply Voltage—Part I: Model Formulation

We provide, in detail, three examples of the application of our stochastic model (a companion paper in this journal) that provides analytical expressions for the probability distribution of the propagation delay time of logic signals through a CMOS inverter when the inverter power supply voltage ${V_{{{\text{dd}}}}}$ (more precisely, gate voltage ${V_{\text{GS}}}$ ) is itself probabilistic for some reason (e.g., system noise or a random external electromagnetic disturbance). Since the propagation delay time is a function of the value of ${V_{\text{dd}}}$ , then some values of ${V_{\text{dd}}}$ may produce values of inverter propagation delay time that cause the circuit in which the inverter resides to malfunction (e.g., by resulting in a delay time value not conforming with the delay time margins for that circuit). The examples we present for some possible probability density functions (pdfs) for ${V_{\text{dd}}}$ are 1) Gaussian density, 2) uniform density on a finite interval, and 3) delta density. The Gaussian density is an example of a continuous one, whereas the uniform density is an example of a discontinuous one; the delta density is of interest for providing guidance in handling discrete pdfs—not explicitly treated in the above referenced paper—since such pdfs may be represented as weighted sums of δ -functions. Based upon the derived inverter propagation delay time probability distribution, we derive, for the Gaussian density, a probability for the malfunction of a circuit containing a single inverter subject to such a stochastic ${V_{\text{dd}}}$ .

Threshold Voltage Characteristics for Silicon Nanowire Field-Effect Transistor With a Double-Layer Gate Structure

In this paper, the threshold voltage characteristics of silicon nanowire metal–oxide–semiconductor field-effect transistor (MOSFET) with a double-layer gate structure are presented. This type of device is considered to be the most promising application of nanodevice in ultralarge-scale integration, due to several advantages such as similar operation principle as the junctionless nanowire transistor, the screening effect of the upper gate (UG) to shield the lower gate MOSFETs from external electromagnetic disturbance, the tradeoff between the short channel and the thick-gate oxide layer, and the compatible fabrication process with the conventional MOS technology. In this paper, the relations of threshold voltage versus the gate length, the UG bias, the substrate bias, the drain bias, and the temperature are measured and analyzed. Moreover, the penetration effect of the UG electric field is proposed to interpret the short-channel characteristics of the device, and a piecewise curve model is presented to reveal the underlying physics of the relation of the threshold voltage versus the drain bias. The double-layer gate structure technology enables the design of many devices, such as small-signal analog circuit units, single-electron devices, and quantum bit cells.

Evaluation of the Effectiveness of Protective Patches on Acupoints to Preserve the Bioenergetic Status against Magnetic Fields.

The potentially harmful nature of electromagnetic fields (EMF) and static magnetic fields (SMF) has become a major problem in recent years. All these elements could be combined to produce cellular responses. For example, the orientation of molecules of water or other complex molecules, growth and cell viability, cell morphology, and intracellular metabolic pathways have demonstrated binding to magnetic fields. The effect of EMF and SMF on humans is a topic of great importance, especially because modern technology has introduced artificial magnetic fields such as those generated by power lines, mobile communications, and medical imaging equipment. A relevant problem is certainly that of professional exposure. The aim of this study was the evaluation of the effectiveness of a commercially available device, Skudo® patches (Edil Natura S.r.l., Novara, Italy), in protecting magnetic resonance operators from the influence of magnetic fields such as those present in the workplace. Skudo® patches are designed to protect microareas of the body from external electromagnetic disturbances. In this study, 10 male Italian volunteers aged between 50 and 60 were enrolled in the hospital. All participants were subjected to measurements at 4 specific time points to evaluate the effectiveness of Skudo® to counteract both EMF and SMF magnetic fields by evaluating the level of bioenergetic reactivity. To perform the measurements, a variant of the Ryodoraku method has been used, based upon the assessment of electropermeability. In particular, 12 acupoints were measured, one for each of the main meridians. This study shows that both SMF and EMF cause an alteration of the body's water system. The application of Skudo® patches determines a regularization of bioenergetic levels related to the water system. The application of Skudo® on the EMF source has suppressed the imbalance effect of the water system found in the subject without any protection.

Influence of External Electromagnetic Disturbance on the Optical Fiber Properties in WDM Systems

The influence of external electromagnetic disturbance on the optical fiber properties in WDM systems have been studied with OptSim 5.0 simulation software. The obtained results show that electromagnetically induced polarization changes in WDM systems, which are working on a SSMF base can severely reduce the system perfomance. Therefore, the channel spacing must be increased. For example, in the case of 45° polarization rotation the spacing increase from 50 GHz to 100 GHz is necessary. Ill. 7, bibl. 9 (in English; summaries in English, Russian and Lithuanian).

Pellet photonic innovant gas sensor using catalysis and integrated photonics

This article addresses the main results of the PEPS (PEllet Photonic Sensor) project, whcich aims at developing a new gas sensing transducer via a technological breakthrough: the combination of photonics (insensitive to external electromagnetic disturbances) and catalysis (reversibility, limited energy consumption). Indeed, catalytic reactions are often exothermic and this heat can modify the properties of optical devices. The experimental studies performed during the PEPS project highlighted the rapid and reversible response at room temperature of catalytic powders towards different concentrations of H2 in air. The thermal and optical properties of the materials used for the integrated photonic component have also been studied. These results have been exploited for the design of the photonic transducers. The feasibility of the physical transduction principle has been demonstrated by developing different prototypes based on Bragg gratings and Multimode Interference Components.

Physical simulation of the conditions and parameters of the reliability of the magnetic inspection of steel cables

A physical model of the magnetic inspection process of steel cables, which is based on the linear approximation of the influence of the ratios (γ*) of effective external electromagnetic disturbances (noises) and information-signal values of a flaw defector is presented. Based on the application in a model of simulation specimens of the wear of steel cables with a relative amplitude magnetic permeability that is smaller by a factor of 1.5–3 than that of cable steels, a procedure for the express evaluation of the reliability of the inspection of cables in their wear range of 0–25% was designed.

Semi-classical modeling of nano-mechanical transistors

The introduction of vibration-based Nano Electro-Mechanical Transistors (NEMT) opens a new horizon for mechanics in computer science. NEMT working principle is based on an electrical charge shuttle between two electrodes operated by a vibrating conductor body. Advantages of these novel devices would be very low power dissipation, limited influence of external electromagnetic disturbances, and improved thermal resistance. The paper introduces an analytical model for such a device, in which the matching of a mechanical resonator and an electric circuit is studied: the coupling is provided by capacitance effects, electrostatic force and the quantum tunneling. The approach is quasi-classical, describing the quantum phenomena through a non-linear conductance and using a continuous variable for the charges. Through suitably introduced simplifications, the model is reduced to a set of two differential equations in terms of pillar position and charge. These equations represent the simplest model still preserving the basic phenomenology of the investigated system. Numerical simulations show different possible motion regimes, both in the single- and multiple-module configurations, the latter able to reproduce the conventional transistor functionality. This opens the way to mechanical voltage-driven switches or amplifiers.

Phase stabilizing method based on PTAC for fiber-optic interference fringe projection profilometry

Fiber-optic interference fringe projection profilometry for high-precision 3D (Three-dimensional) shape reconstruction which is insensitive to external electromagnetic disturbances. We designed a system which takes advantage of Mach–Zehnder interferometer structure and Young’s double pinhole interference principle to realize fringe projection, while utilizing Fresnel reflection on fiber end face and interference to constitute close-loop feedback model, achieving precise control of the projected fringe phase with PTAC (AC Phase Tracking). A root-mean-square phase stability of 4mrad. The spin filter is used for eliminating the noise, meanwhile preserving details of the fringes; finally we realized real-time 3D shape retrieving through Fourier transformation profilometry, the measuring time of the whole system is less than 250ms.

Uncertainty and reproducibility in measuring the data acquisition system immunity to conducted disturbances

The paper presents an original methodology for testing the data acquisition system immunity to conducted disturbances and for evaluating the typical uncertainty intervals to be assigned to these kinds of measurements. As in any data measurement system, even in those consisting of a desktop computer equipped with a PCI data acquisition board, several devices and components are involved in the process of acquiring, sampling and digitizing the analogue signal, and eventually presenting the digital values to the user. Therefore, there are many possible coupling paths between the measurement system and external electromagnetic disturbances, in principle both radiated and conducted, which would require a large number of configurations to be tested. Indeed, with particular reference to radiated couplings, their effects generally depend on the adopted test setup. In addition, the electromagnetic boundary conditions of the test site can significantly affect the measurement results. Both these aspects should be carefully taken into account because they are the main cause for ambiguous results and well-known issues in inter-laboratory comparisons. In this framework, the aims of this study are (i) to investigate which components or component configurations influence the data acquisition system immunity most significantly; (ii) to provide a practical way to effectively test these types of measurement system and (iii) to assess the related uncertainty budget in order to qualify the test results. Finally, the site-to-site reproducibility of the measurements has been evaluated by comparing results obtained in two different laboratories.

Asymptotic field operators in quantum field theory

The formulation of the asymptotic condition in quantum field theory is viewed as a problem in asymptotic particle interpretation of a field theory and is solved in terms of a natural limiting process involving the retarded vacuum expectation values. Starting with the Haag-Brenig theorem translated into operator language we obtain the asymptotic fields for a nonrelativistic self-coupled field. Transcription of this expression for the asymptotic field in terms of a retarded two-point Green's function motivates the more general definition of the asymptotic field in the presence of external forces. The equations of motion as well as the commutation relations for these asymptotic fields are derived, and it is shown that in sufficiently simple cases this definition coincides with the usual definition. In addition to this conventional asymptotic field, in general, there are asymptotic fields which create particles in bound states. The definition generalizes in a natural manner to many-particle asymptotic fields and, in particular, to asymptotic fields which create and annihilate multiparticle bound states. This construction is facilitated by the standard analysis of the Bethe-Salpeter amplitudes. The familiar “contraction rules” are deduced within the present formalism. These developments are extended to relativistic field theory, again in terms of a limiting procedure involving the retarded Green's functions. As a particular application it is shown that the asymptotic electron field describes electrons which react to an external electromagnetic disturbance in the same manner as physical electrons, i.e., with their anomalous moment and vacuum polarization effects etc., in addition to the “normal” gauge invariant interaction. We briefly discuss the implications for theories with unstable quanta, and draw attention to the possibilites offered for a consistent theory of interacting particles involving unstable ghost fields.