Elementary Pulses Research Articles

Statistical features of the response of a superconducting hot-electron bolometer to extremely weak terahertz pulses of picosecond and nanosecond duration

We study the statistical distributions of the output signals of a superconducting hot-electron bolometer (HEB) detector exposed to weak photon pulses of 1 THz (terahertz) frequency. Pulses with variable photon numbers were generated through strongly non-degenerate parametric downconversion (PDC) in a LiNbO3 crystal at 4.8 K. Fundamental differences in histograms are found between two PDC pumping modes, with pulse widths of 28 ps and 10 ns. HEB response to a picosecond THz pulse was detected in the form of a single elementary electrical pulse (SEP), with the average amplitude proportional to radiation intensity and dispersion relative to the bolometer's dark current. HEB responses to extremely weak radiation intensities have been recorded using nanosecond pulsed illumination. We found that nanosecond histograms are asymmetrical and broaden as radiation intensity increases, indicating that the nanosecond response consists of several SEPs. Poisson–Gauss approximation of histograms indicates that not only the average number of SEPs increase but also the average amplitude of a SEP increases with increasing power of incident THz radiation.

Role of seismogeological modeling in the attribute analysis of seismic data using the example of the forecast of the thickness of the Yu3t formation of the southwestern Kazakhatsan oil field

Relevance. The need to introduce the results of two-dimensional seismogeological modeling into seismic data attribute interpretation to identify signs of manifestation of the target object of the forecast in the wave field of seismic recording and assess the influence of interference of the host strata on it. Object. Highly productive terrigenous Upper Jurassic Yu3t formation of the Nizhnekumkol formation of the oil field of southwestern Kazakhstan, formed under conditions of a cone of liquid proluvial fan. Aim. To assess the impact of the interaction of the enclosing strata of the Upper Jurassic Yu3t formation on the seismogeological forecast of its capacities within the considered oil field. Methods. Two-dimensional seismogeological modeling based on the analysis of the frequency response and determination of the shape of the elementary pulse of seismic recording in the interval of the productive formation. Analysis of the thicknesses of geological inhomogeneities overlying the Yu3t formation in order to assess their effect on the wave characteristic of the time interval of research. Results. The performed two-dimensional seismogeological modeling showed that the amplitude characteristic of the negative phase of the wave packet of the target object, characterizing the power of the Yu3t formation, is affected to varying degrees by the overlapping thicknesses of the Yu3a formation and the inter-reservoir seal P1. Based on the modeling results, it was concluded that the basis for predicting the thickness of the Yu3t formation should be considered an attribute map of the difference in amplitudes of the upper positive (A) and average negative (B) phases of the considered wave packet A, B, C. At the same time, the correlation dependences of the obtained attribute with the values of the thickness of the Yu3t formation in drilled wells should be considered within the areas outside the zone the influence of other elements complicating the wave pattern of the target object (tectonic disturbances and erosive protrusions of the foundation).

ARTERIAL STIFFNESS IN PATIENTS WITH HYPERTENSIVE CRISIS

Objective: The aim of this study was to determine if patients with the hypertensive crisis have higher pulse wave velocity compared to the patients with arterial hypertension without it. Design and method: In this case-control study which lasted from January 2020 to December 2021, 61 patients (36 males, 25 females) with the hypertensive crisis were analyzed at the Emergency department in Clinical Hospital Merkur, Zagreb. The hypertensive crisis was defined as a rapid increase in systolic blood pressure above 180 and/or diastolic above 120mmHg (SBP range 181–208mmHg). On the other hand, in the control group, we analyzed 45 patients (24 males, 21 females) with confirmed arterial hypertension by a 24h-ambulatory blood pressure monitor (BTL Cardiopoint, SBP > 130/80mmHg or taking antihypertensives) without evidence of hypertensive crisis (SBP range 115–156mmHg) in two family medicine practices. Elementary lab results and pulse wave velocity (by Agedio B900) were checked in all patients. Patients were divided into two additional groups by age (51–60, 42 patients and 61–70 years, 64 patients). Mann-Whitney U test was used for the analysis of non-parametric variables in Statistica v.10.0. Results: Patients with hypertensive crisis had a significantly higher heart rate (median 78 vs. 69 bpm, U = 714; p < 0.001), fasting glucose (median 5.5 vs. 6.0 mmol/L, U = 804.5; p < 0.01), body mass index (median 31.0 vs. 27.9 kg/m2, U = 889; p < 0.001), nocturnal SBP drop (median 15.5 vs. 9.8%, U = 386; p < 0.05), and augmentation index (median 42 vs. 19%, U = 686; p < 0.001). In both younger and older group, patients with hypertensive crisis had statistically significantly higher pulse wave velocity (median younger: 9.3 vs. 8.1m/s, U = 65.5; p < 0.001; older: 10.7 vs. 9.0m/s, U = 19; p < 0.001) shown in the Figure 1. In younger group patients with hypertensive crisis have 8.5 times higher chances of having pulse wave velocity above reference value (>8.0m/s; CI = 1.57–46.87, p < 0.001) while in older group that chance was 108 times higher than in controls (reference value >9.5m/s; CI = 13.83–843.33, p < 0.001). Conclusions: Patients with hypertensive crisis had statistically higher pulse wave velocity values, heart rate, fasting glucose, body mass index, and nocturnal SBP drop compared to patients with arterial hypertension without crisis.

High-Voltage Pulse Generators for Electroporation Applications: A Systematic Review

In recent years, the use of electroporation process has attracted much attention, due to its application in various industrial and medical fields. Electroporation is a microbiology technique which creates tiny holes in the cell membrane by the applied electric field. The electroporation process needs high-voltage pulses to provide the required electric field. To generate high-voltage pulses, a pulse generator device must be used. High-voltage pulse generators can be mainly divided into two major groups: Classical pulse generators and power electronics-based pulse generators. As their name suggests, the first group is associated with the primary and elementary pulse generators like Marx generators, and the second group is associated with the pulse generators that have been updated with the advancement of power electronics like Modular Multilevel Converters. These two major groups are also divided into several subgroups which are reviewed in detail in this paper. This study reviews the literature presented in the field of pulse power and pulse generators proper for the electroporation process and addresses their strengths and weaknesses. Several tables are provided to highlight and discuss the characteristics of each subgroup. Finally, a comparative study among different groups of pulse generators is performed which is followed by a classification performance analysis.

HYPERTENSIVE URGENCY, EMERGENCY AND KIDNEY FUNCTION

Objective: The aim of this study was to determine risk factors for hypertensive crisis development just as an impact of the kidney function on it. Design and method: From January to October 2019, 237 patients (109 males, 128 females) with hypertensive crisis were analyzed at the Emergency department in Clinical Hospital Merkur, Zagreb. We defined the hypertensive crisis as a rapid increase in blood pressure above 180/120mmHg (SBP range 182–260mmHg). Hypertensive crises were divided into two subgroups due to the evidence of end-organ damage. Elementary lab results and pulse wave velocity were checked in all patients. Results: Hypertensive urgency was found in 184 patients (77.64%), emergency in 53 (22.36%). Comparison of these two subgroups showed that patients with an emergency were significantly older (70.51 vs. 64.44 years, p < 0.01), had significantly elevated serum glucose levels (10.04 vs. 6.94mmol/L, p < 0.0001), decreased glomerular filtration rate (CKD-EPI formula 75.96 vs. 59.15 mL/min/1.73m2, p < 0.0001) and high heart rate (mean 96.32 vs. 77.17bpm, p < 0.0001) which showed as the most significant risk factor. Body mass index didn’t show any relevance in the hypertensive crisis development (31.26 vs. 30.58 kg/m2, p = 0.18). Hypertensive emergency incidence increased with a decline in kidney function. Such events developed in 16.94% patients with CKD stage 1, 14.42% in stage 2, 34.61% in stage 3a, 50.00% in stage 3b, 60.00% in stage 4 and 50.00% in stage 5. Within main groups, patients were divided into two groups whether they used antihypertensive medication. A group of 53 patients was without medication (22.36%) of which 13 met criteria for a hypertensive emergency. Pulse wave velocity was much higher in patients with CKD-EPI < 45 ml/min/1.73m2 (13.01 vs. 10.74m/s, p = 0.01). Even though female patients were significantly older (69.02 vs. 62.02years, p < 0.0001), no other differences between genders were found. Conclusions: Age, elevated plasma glucose and a decline in glomerular filtration rate combined with high heart rate values, but gender and body mass index independently are the main factors which are linked to the development of hypertensive emergency.

The study on the possibility of forming quadrature components based on Barker codes

The formative stages of the minimum frequency manipulation with a continuous phase with a modified algorithm of formation of quadrature components and Barker code encoding are discussed in this article. The results of modelling the digital sequences scheme using this method are presented. The method of minimum frequency manipulation with continuous phase with changed algorithm of quadrature components formation and Barker code encoding has been described earlier. The minimal spreading of frequencies for minimum frequency manipulation by which the orthogonality of opposite signals is still maintained, it is implemented when the manipulation index is m = 0.5 and constitutes the value that is inversely proportional to the doubled duration of the elementary pulse transmitted by the sequence, 2Δf = 1/2τ.

Reconstrução das melodias do candomblé ketu nº 194 e 201 da Coleção Camargo Guarnieri a partir do conceito de linha-guia

Este artigo apresenta o processo de reconstrução de duas melodias de candomblé ketu coletadas por Camargo Guarnieri na cidade de Salvador, em 1937. Sob direção de Mário de Andrade, o trabalho de campo não contemplou o registro mecânico das melodias, tampouco foram anotados os ritmos dos instrumentos de percussão, considerados fundamentais aos rituais. Sendo assim, o estudo teve como objetivo evidenciar que as melodias nº 194 e 201, transcritas pelo maestro, possuem uma estrutura rítmica que é orientada pela linha-guia tocada no gã. Contando com uma revisão de literatura do conceito de linha-guia e da função musical do gã, as cantigas foram analisadas e confrontadas com teorias sobre a rítmica de matriz africana, como os conceitos de timeline, pulsação elementar, circularidade, bem como binarização de ritmos africanos. Posteriormente, foi criado um procedimento padronizado para o processo de reconstrução das melodias, com suporte teórico e prático, tendo o empirismo e a experiência do campo como pilares metodológicos. Embora tenha sido demonstrado que as linhas-guia servem de suporte rítmico para as cantigas do candomblé ketu, ficou evidente que a coleta de Guarnieri deu prioridade ontológica às melodias em detrimento do ritmo. Por outro lado, é possível concluir que a execução musical dos instrumentos de percussão envolve um certo grau de complexidade que merece ser destacado e pesquisado.

Analysis of Estimation Error of Skewness and Kurtosis of Bunimovich-Rice Processes with Exponentially Power Waveform of Pulses

Mathematical expectations and variances of estimates of skewness and kurtosis coefficients of the noise signal model have been derived in this study. The specified noise signals represent the Bunimovich–Rice processes with exponentially power waveform of pulses expressed in terms of cumulant coefficients of the specified processes. It is shown that the distribution of instantaneous values of Bunimovich–Rice processes is quite different from the Gaussian distribution. The root-mean-square and relative estimation errors of skewness and kurtosis coefficients depending on of the time constant and waveform parameter of elementary pulses, as well as distributions of pulse amplitudes (degenerate and gamma distributions) and their intensities are analyzed. Expressions for finding the minimal sample volumes are obtained that ensure the specified values of relative errors in estimating the skewness and kurtosis coefficients of Bunimovich–Rice processes. The minimal sample volumes depending on parameters of these processes have been determined that ensure the relative estimation errors, which do not exceed 1%.

Development of the method for decomposition of superpositions of unknown pulsed signals using the second­order adaptive spectral analysis

We considered the issue of intuitive analysis, processing, and synthesis of unknown pulse sequences in a detailed form. We studied both classical methods of analysis with all pluses and minuses and the developed prospective method created on their basis. The developed method is adaptive, it is based on the consistent use of various methods of spectral analysis, which increases reliability, sensitivity, and resolution capability of visual analysis of echo-pulse images. Thus, we solved the problem on processing pulse signals. The proposed method makes it possible to increase resolution capability in the processing of signals and images without using a priori information on the form of elementary pulses. It is resistant to the influence of measuring noise. We presented the results of numerical simulation and actual verification on the example of a seismic image. The considered method has a significant development potential, both in theoretical and application aspects (first of all, in areas of ultrasonic medical diagnosis, seismic imaging, and non-destructive testing).

Modeling Lane Keeping by a Hybrid Open-Closed-Loop Pulse Control Scheme

This paper presents a novel methodology for modeling human lane keeping control by characterizing a unique concept of elementary steering pulses , which are motor primitives in man–vehicle systems. The novelty of the paper is the introduction of elementary steering pulses that have been evidently extracted from naturalistic driving data through machine learning techniques (data-driven modeling), and are incorporated into an alternative steering control scheme. This newly proposed hybrid-open-closed-loop control scheme starts an elementary steering pulse with an open-loop steering actuation, representing real human's reflex responses triggered by human lane keeping errors, and adjusts it back with the traditional closed-loop control. This shows a significant improvement on both the stability and the matching performance to real driving events. Online measurement of the key metrics in the steering process provides a new tool for monitoring driver states, and the biofidelic steering model may provide human-like qualities for future automated lane keeping systems. Both will add to the array of tools available for achieving autonomous and semiautonomous driving systems, which greatly benefits the current vehicle industry.

Within-footprint roughness measurements using ICESat/GLAS waveform and LVIS elevation

The surface roughness is an important characteristic over an ice sheet or glacier, since it is an identification of boundary-layer meteorology and is an important limiter on the accuracy of surface-height measurements. In this paper, we propose a simulation method to derive the within-footprint roughness (called simulation-derived roughness) using ICESat/GLAS echo waveform, laser vegetation imaging sensor (LVIS) elevations, and laser profile array (LPA) images of ICESat/GLAS. By dividing the within-footprint surface into several elements, a simulation echo waveform can be obtained as the sum of the elementary pulses reflected from each surface element. The elevation of the surface elements, which is utilized to get the return time of the elementary pulses, is implemented based on an LVIS interpolated elevation using a radial basis function (RBF) neural network. The intensity of the elementary pulses can be obtained from the thresholded LPA images. Based on the return time and the intensity of the elementary pulses, we used the particle swarm optimization (PSO) method to approximate the simulation waveform to the ICESat/GLAS echo waveform. The full width at half maximum) (FWHM) of the elementary pulse was extracted from the simulation waveform for estimating the simulation-derived roughness. By comparing with the elevation-derived roughness (derived from the elevation) and the waveform-derived roughness (derived from the ICESat/GLAS waveform), the proposed algorithm can exclude the slope effect from waveform width broadening for describing the roughness of the surface elements.

Comparison of deterministic and stochastic approaches for isotopic concentration and decay heat uncertainty quantification on elementary fission pulse

Uncertainty quantification of interest outputs in nuclear fuel cycle is an important issue for nuclear safety, from nuclear facilities to long term deposits. Most of those outputs are functions of the isotopic vector density which is estimated by fuel cycle codes, such as DARWIN/PEPIN2, MENDEL, ORIGEN or FISPACT. CEA code systems DARWIN/PEPIN2 and MENDEL propagate by two different methods the uncertainty from nuclear data inputs to isotopic concentrations and decay heat. This paper shows comparisons between those two codes on a Uranium-235 thermal fission pulse. Effects of nuclear data evaluation’s choice (ENDF/B-VII.1, JEFF-3.1.1 and JENDL-2011) is inspected in this paper. All results show good agreement between both codes and methods, ensuring the reliability of both approaches for a given evaluation.

High-frequency variations of spectral lines in cromospherically active stars 61 cyg AB

We report on the detection of rapid variability in subsecond mode in the Balmer lines of hydrogen, lines Ca II H,K, and b Mg I triplet in chromospherically active stars 61 Cyg A, B. The spectral observations of 61 Cyg A, B were performed with MMCS spectrograph in Cassegrain’s focus of the 2-m telescope at peak Terskol (R = 13000), with a grating spectrograph mounted on a 60-cm telescope at peak Terskol (R ≈ 100), and a 60-cm telescope of the Andrushivka Observatory (R ≈ 200). The observations were carried out in the framework of international campaign of observations of variable stars using the Synchronous Network of Telescopes. The high-resolution spectra were obtained with intervals of approximately 2 minutes. The low-resolution spectra were obtained with intervals from 2 to 3 seconds. Spectral monitoring lasted from 30 minutes to 2 hours. We found that chromospherically active dwarf stars 61 Cyg A, B, having extensional spots on their surfaces exhibit rapid variations in the hydrogen lines, lines CaII H, K of ionized calcium and chromospheric triplet b Mg I on a time scale from approximately 2 seconds to approximately 2 minutes. Variations in the intensity of lines range from 1.5% in the Balmer series of hydrogen to approximately 0.5% in the lines of b Mg I triplet. These variations are well described by the shot noise model in the form of random elementary pulses with the frequency of occurrence of a few fractions of events per second to a few events per second. Comparison of rapid variations in chromospheric lines with different time intervals demonstrates the transient nature of this activity both on short (subsecond) and long-time scales.

Modular baseband pulse generator for impulse‐radio ultra‐wideband transmitter

A new concept of burst generator architecture dedicated to impulse-radio ultra-wideband wireless communication systems is presented. Bursts are generated by using four elementary baseband pulse generators operating in parallel. Thus, the resulting waveform is the amplitude and phase addition of time-overlapped pulses. The circuit has been implemented in 65 nm CMOS technology under a 1.2 V supply voltage. Simulation results are presented exhibiting a power consumption of 7.24 mW.

Кодер и декодер фрактальных сигналов гребенчатой структуры

The article presents a coder and decoder of fractal signals of comb-type structure (FSCS) based on microcontrollers (MC). The coder and decoder consist of identical control modules, while their managed modules have different schematic constructions. The control module performs forming or recognition of signals, and also carries out the function of information exchange with a computer. The basic element of the control module is a PIC18F2550 microcontroller from MicroChip. The coder of the system forms fractal signals of a given order according to the information bits coming from the computer. Samples of the calculated values of the amplitudes of elementary rectangular pulses that constitute the structure of fractal pulses are stored in the memory of the microcontroller as a table. Minimum bit capacity of the DAC necessary for the generation of FSCS of fourth order is four bits. The operation algorithm, "wired" into the controller of the program, provides for encoding of the transmitted information by two-bit symbols. Recognition of the start of transmission of each byte in communication channel is performed by the transmission of the timing signal. In a decoder the microcontroller carries out reception and decoding of the received fractal signals which are then transmitted to the computer. The developed algorithm of the program for the microcontroller of the decoder is carried out by determination of order of fractal impulse after the value of sum of amplitudes of elementary impulses, constituents fractal signal. The programs for coder and decoder are written in "C". In the most critical places of the program influencing on the fast-acting of chart “assembler” insertions are done. The blocks of the coder and decoder were connected with a coaxial 10 meters long cable with an impendance of 75 Ohm. The signals generated by the developed coder of FSCS, were studied using a digital oscillograph. On the basis of the obtained spectrums, it is possible to draw a conclusion, that the fractal signals formed by the coder are wideband and can be used in noise-resistant and protected communication systems.

Nonstationary elementary-field light randomly triggered by Poisson impulses

A stochastic theory of nonstationary light describing the random emission of elementary pulses is presented. The emission is governed by a nonhomogeneous Poisson point process determined by a time-varying emission rate. The model describes, in the appropriate limits, stationary, cyclostationary, locally stationary, and pulsed radiation, and reduces to a Gaussian theory in the limit of dense emission rate. The first- and second-order coherence theories are solved after the computation of second- and fourth-order correlation functions by use of the characteristic function. The ergodicity of second-order correlations under various types of detectors is explored and a number of observables, including optical spectrum, amplitude, and intensity correlations, are analyzed.

Stochastic pulse models of a partially-coherent elementary field representation of pulse coherence

A representation of the mutual coherence function (MCF) of a light pulse as an incoherent sum of partially-coherent elementary pulses is introduced. It is shown that this MCF can be decomposed into fully and partially-coherent constituents and three different pulse models of partially-coherent constituents are constructed: single elementary-pulse fluctuations, emission of elementary fields driven by white noise, and elementary pulses triggered by Poisson impulses. The fourth-order correlation function of this last model includes as limit cases those of the fluctuating-pulse and noise-driven-emission models. These results provide a means of extending elementary-field models to higher-order coherence theory.

Application of the orthogonal representation method for determining the probability densities of typical models of fluctuation signals

The theoretical and experimental probability densities of fluctuation signals have been determined for typical models of elementary pulses based on their orthogonal representations and using mathematical simulation. The obtained results showed the validity of such representation.

Orthogonal‐polarization multipulse sequences

It is well known that using orthogonal polarizations for subpulses in multipulse sequences can be used to reduce clutter contributions in these modes. In this paper we show that further improvements are achieved if the orthogonality is taken into account already when constructing the codes. Using orthogonal polarizations, one can use denser transmission patterns, including elementary pulses without gaps between them, patterns that have severe range ambiguities when only a single polarization is used. Furthermore, correlations are computed separately for each combination of elementary pulse polarizations. Consequently, it is possible to have longer multipulse sequences without gaps in the lag sequence, it is possible to compute the odd lags as well as the even ones, and it is permissible to have some lags multiply obtained without range ambiguity. This means that using orthogonal polarizations when creating the multipulse transmission pattern gives flexibility well beyond the single‐polarization case. This flexibility can be used to design patterns suited to particular experimental requirements. Furthermore, we point out that the improvement in clutter might have a more dramatic impact than is generally realized, particularly in high‐SNR situations where the improvement in speed is up to a factor of 4. Examples are given of single‐ and multiple‐frequency patterns that are not usable if only one polarization is available. Although all incoherent scatter radars in use today, except Jicamarca, lack orthogonal polarization capabilities, designers of the next generation of radars might find the improvements described herein to be of interest.

Pulsed Sound Waves in a Compressible Fluid

The propagation along oz of pulsed sound waves made of sequences of elementary unit pulses U (sin τ) where U is the unit step function and τ = kz －ωt is analyzed using the expansion of U (sin τ) and of the Dirac distribution δ (sin τ) in terms of τ－nπ where n is an integer. Their properties and how these pulsed sound waves could be generated are discussed.