Typical Pulse Research Articles

More than stridulation: signal interaction and constraint in the complex vibroacoustic courtship of a cricket

Field crickets (Gryllidae) produce sounds by tegminal stridulation, well-studied for its role in female attraction and choice. However, understanding female preferences for their courtship song remains elusive, despite considering additional chemical, visual, and thermal signals. Beyond stridulation, crickets also display vibrational courtship behaviours that remain largely unexplored. Using Acheta domesticus as a model, we conduct the first comprehensive analysis of the entirety of vibroacoustic courtship signals in crickets, including their interaction. Employing audio recording, laser vibrometry, and videorecording, we unveil a complex signal involving simultaneous wing stridulation, body tremulation, and leg drumming against the substrate in a prolonged display, unique among insects. We identify robust correlations, coupling, and coordination between these signal components. We show the tightest coupling between the two types of stridulation pulses, and between tremulation and drumming signals, while drumming-stridulation coupling is less consistent, revealing a constraint on drumming performance. This constraint in the expression of one signal component, without a trade-off, represents a specific case within complex dynamic signalling. In addition, we find no correlation between drumming rate and its accuracy relative to stridulation, challenging common expectations. Our findings indicate that the information conveyed by the complex courtship display in A. domesticus is not simply proportional to that in the song, shedding light on previous ambiguities surrounding its function. Spectral-intensity analysis indicates the closest perceptual connection between stridulation and drumming signals, likely commonly influencing female choice, while proposing another function for tremulation. Further research should delve deeper into the function of this intricate signal.

Reservoir Computing System with Diverse Input Patterns in HfAlO-Based Ferroelectric Memristor.

Ferroelectric memristors, particularly those based on hafnia, are gaining attention as potential candidates for neuromorphic computing. These devices offer advantages over perovskite-based ferroelectric memristors owing to their simpler structures, compatibility with complementary metal-oxide semiconductor technology, and low-power consumption characteristics. Additionally, improvements in ferroelectric memristor's performance, such as enhancing tunneling electro resistance (TER) and polarization retention, can be achieved using methods like aluminum doping and insulating film deposition. In this study, we implement a physical reservoir computing (RC) system utilizing the metal-ferroelectric-insulator-semiconductor-structured ferroelectric memristor based on Al-doped HfO2 as an artificial synapse. Specifically, we ensure the universality and diversity of the system by experimentally demonstrating a robust reservoir layer capable of handling various types of input pulses. To utilize the ferroelectric memristor in the reservoir layer of the RC system, we employ partial polarization switching of ferroelectric materials. We measure the retention loss characteristics of the device for pulse amplitude, interval, and width, and quantify the time constant values by fitting them to a stretched exponential function. Additionally, we validate the suitability of the fabricated device as an artificial synapse by mimicking various short-term plasticity functions of biological synapses. Furthermore, we experimentally demonstrate various applications related to learning and memory of the brain, such as image training and Pavlov's experiment, utilizing the short-term memory characteristics of the fabricated device. Lastly, we evaluate the robustness of the RC system under various input conditions by employing the fabricated device as a reservoir layer.

Activation thresholds for electrical phrenic nerve stimulation at the neck: evaluation of stimulation pulse parameters in a simulation study

Abstract Objective. Phrenic nerve stimulation reduces ventilator-induced-diaphragmatic-dysfunction, which is a potential complication of mechanical ventilation. Electromagnetic simulations provide valuable information about the effects of the stimulation and are used to determine appropriate stimulation parameters and evaluate possible co-activation. Approach. Using a multiscale approach, we built a novel detailed anatomical model of the neck and the phrenic nerve. The model consisted of a macroscale volume conduction model of the neck with 13 tissues, a mesoscale volume conduction model of the phrenic nerve with three tissues, and a microscale biophysiological model of axons with diameters ranging from 5 to 14 µm based on the McIntyre–Richardson–Grill-model for myelinated axons. This multiscale model was used to quantify activation thresholds of phrenic nerve fibers using different stimulation pulse parameters (pulse width, interphase delay, asymmetry of biphasic pulses, pulse polarity, and rise time) during non-invasive electrical stimulation. Electric field strength was used to evaluate co-activation of the other nerves in the neck. Main results. For monophasic pulses with a pulse width of 150 µs, the activation threshold depended on the fiber diameter and ranged from 20 to 156 mA, with highest activation threshold for the smallest fiber diameter. The relationship was approximated using a power fit function x −3. Biphasic (symmetric) pulses increased the activation threshold by 25 to 30 %. The use of asymmetric biphasic pulses or an interphase delay lowered the threshold close to the monophasic threshold. Possible co-activated nerves were the more superficial nerves and included the transverse cervical nerve, the supraclavicular nerve, the great auricular nerve, the cervical plexus, the brachial plexus, and the long thoracic nerve. Significance. Our multiscale model and electromagnetic simulations provided insight into phrenic nerve activation and possible co-activation by non-invasive electrical stimulation and provided guidance on the use of stimulation pulse types with minimal activation threshold.

Temporal airy pulses efficiency in thin glass dicing

Abstract Ultrashort pulse laser sources are useful tools for micro- and nano-processing large band gap dielectric materials. One of the biggest advantages of these pulses is the possibility to reach high intensity peaks that promote absorption even in materials transparent to the laser wavelength. In addition, if the pulse temporal distribution is modified, energy absorption enables the ablation of small diameter holes with large depths. In this work, we present preliminary results that implement three types of pulses as precursors for glass dicing: Bandwidth-limited (30 fs at 785 nm), positively, and negatively dispersed Temporal Airy Pulses (TAP). The material of choice was 170 μm thick soda-lime glass, inscribed at 1 kHz repetition rate in tight (50× objective) and loose (20× objective) focusing conditions for different laser energies and scanning speeds. After laser processing, the glass was diced by mechanical stress, with a home built four-point bending stage. We analyzed the quality of the scribed lines at the surface and in cross-section after breaking, as well as the necessary breaking force for all three types of laser pulses. We report that positive TAP produced a neat, flat-cut edge on the glass samples compared with the other implemented pulses.

A Pulsed Bubble‐Driven Efficient Liquid‐Solid Triboelectric Nanogenerator

AbstractHarnessing energy from underwater bubbles has garnered significant attention, particularly for powering off‐grid circuitry. However, the efficiency of bubble‐driven liquid‐solid interface charge transfer remains low. This research unveils a phenomenon: accelerated bubble slippage enhances liquid‐solid interfacial charge transfer. Building upon this discovery, a pulse bubble‐based power generation technique is proposed, achieving an energy density of 24.2 mJ L−1 generated by pulsed bubbles. The crux of pulse bubble power generation lies in the precise control of impact velocity. By meticulously regulating the impact kinetic energy of bubbles, the accumulated potential energy of multiple small bubbles is converted into instantaneous pulse kinetic energy. A typical pulse bubble is controlled within a 72 ms timeframe, unleashing a surge of energy that can directly illuminate 400 light‐emitting diodes. This approach represents a groundbreaking advancement in underwater energy harvesting technology, dramatically expanding its potential applications.

Generation of switchable rectangular pulsed cylindrical vector beams in a 1.7 µm mode-locking all-fiber laser

In this paper, we demonstrate the generation of switchable rectangular pulsed cylindrical vector beams in a 1.7 µm mode-locking all-fiber laser by nonlinear amplifying loop mirror for the first time. Based on the nonlinear amplifying loop mirror mode-locking technology and mode selection coupler, the rectangular pulsed CVBs can be achieved and switched repeatedly and easily between the dissipative soliton resonance and noise-like pulse states. Furthermore, with the increasing of pump power, the duration of dissipative soliton resonance and noise-like pulse increase from 1.76 ns to 6.36 ns and 1.15 ns to 3.95 ns, respectively. In the meanwhile, both the peak power of dissipative soliton resonance and noise-like pulse are all clamped at 6 W all the time, showing the independence of clamped peak power and pulse type. Our work not only broadens wavelength range of switchable rectangular pulse, but also provides a novel pulse profile application of cylindrical vector beams.

Dark gap solitons in bichromatic optical superlattices under cubic-quintic nonlinearities.

We demonstrate the existence of two types of dark gap solitary waves-the dark gap solitons and the dark gap soliton clusters-in Bose-Einstein condensates trapped in a bichromatic optical superlattice with cubic-quintic nonlinearities. The background of these dark soliton families is different from the one in a common monochromatic linear lattice; namely, the background in our model is composed of two types of Gaussian-like pulses, whereas in the monochromatic linear lattice, it is composed of only one type of Gaussian-like pulses. Such a special background of dark soliton families is convenient for the manipulation of solitons by the parameters of bichromatic and chemical potentials. The dark soliton families in the first, second, and third bandgap in our model are studied. Their stability is assessed by the linear-stability analysis, and stable as well as unstable propagation of these gap solitons are displayed. The profiles, stability, and perturbed evolution of both types of dark soliton families are distinctly presented in this work.

Discharge modes evolution characteristics of metal particle on the spacer surface in AC gas insulated switchgear

Abstract Flashover faults on gas insulated switchgear (GIS) insulators induced by metal particles occur frequently. Previous studies have obtained the characteristics of partial discharges (PDs) induced by metal particles on spacer surfaces, but these characteristics cannot explain the detection failure of ultra-high frequency (UHF) online monitoring. To enable further study of the PD characteristics induced by surface metal particles, the space electric field and a very-high-sensitivity pulse current (PC) measurement system were established. The electric field and PC characteristics of a PD induced by metal particle on the spacer surface of a 126 kV GIS were obtained. Two PD modes were found to be induced by surface metal particles. In addition to the typical pulse discharge (TP), there is a micro-discharge group (MG) mode with low apparent charge and long duration. The average apparent charge of the MG mode is approximately one-tenth of that of the TP at 0.4 pC. Its duration may extend to the millisecond level, causing significant distortion of the spatial electric field while hardly producing UHF signals. Moreover, increasing the applied voltage will increase the proportion of the MG within the total discharge, where this proportion can reach more than 90% before flashover, and the proportion of the discharge pulses that generates UHF signals is as low as 1%. The MG generation mechanism is analysed, the ion group stranded on the spacer surface by the TP changes the local electric field at the tip of the metal particle, which reduces the development length and apparent charge of the MG. Low apparent charge is cleared easily by the background electric field and thus the discharge interval is very short. This paper can provide an important basis for revealing the mechanism of GIS spacer surface discharge induced by metal particles and solving the effectiveness of PD monitoring devices.

Electrically smoothing gain-switched optical pulses from a semiconductor laser diode.

The typical optical pulse from a gain-switched semiconductor laser diode (LD) usually consists of a first-spike (FS) component and a quasi-steady-state (QSS) lasing component. For the stability and accuracy in some specific applications of sensing and detection, it is necessary to achieve a smooth QSS component without the FS component (regarded as spike noise). This Letter reports a technique to smooth the optical pulse shape from gain-switched LDs via stepped electric pulse, which can eliminate or suppress the FS component effectively, without any postprocessing. Rate-equation calculations well reproduced the major features of the experimental results and revealed that the pre-pump of the stepped electrical pulse plays a crucial role by adjusting the accumulated carrier density to be close to threshold before lasing in the LD, which suppresses the FS generation during the main pump injects and allows LD transit more rapidly into the QSS mode. The stepped electrical pulse pump provides a feasible and convenient method to smooth the optical pulse shape of gain-switched semiconductor LDs for various applications.

Beam Dynamics in the Heavy Ion Injector LU2 for the Synchrotron Research Complex (SRC)

The project of the complex for studying ionizing radiation exposure from outer space based on the synchrotron accelerator of protons and various types of ions up to 209Bi is being developed at the Russian Federal Nuclear Center - All-Russian Research Institute ofExperimental Physics (FSUE RFNC - VNIIEF). The accelerator includes two injection complexes (one of which is the source of protons and light ions, the second - heavy ions), the booster accelerator and the main synchrotron. The pulsed type heavy ions linac is being developed at the NRC “Kurchatov Institute” - KCTEF (Kurchatov Complex for Theoretical and Experimental Physics). The ions with mass-to-charge ratio 4÷8 with current of 10 mA will be accelerated up to 4 MeV/u. The linac is proposed, including the RFQ and two DTL sections operating at multiple frequencies. Each DTL section is modular and consists of individually phased H-type resonators (IH-DTLs). Quadrupole lenses located between the resonators for the beam focusing. This DTL structure ensures the accelerator compactness and allows section-by-section configuration and sequential commissioning. 6D beam matching between all sections of the linac is carried out. The results ofbeam dynamics simulation in linear accelerator are presented.

Aquariums as Research Platforms: Characterizing Fish Sounds in Controlled Settings with Preliminary Insights from the Blackbar Soldierfish Myripristis jacobus

This study highlights the potential of aquariums as research platforms for bioacoustic research. Aquariums provide access to a wide variety of fish species, offering unique opportunities to characterize their acoustic features in controlled settings. In particular, we present a preliminary description of the acoustic characteristics of Myripristis jacobus, a soniferous species in the Holocentridae family, within a controlled environment at a zoological facility in the Canary Islands, Spain. Using two HydroMoth 1.0 hydrophones, we recorded vocalizations of the blackbar soldierfish in a glass tank, revealing a pulsed sound type with a peak frequency around 355 Hz (DS 64), offering a more precise characterization than previously available. The vocalizations exhibit two distinct patterns: short sequences with long pulse intervals and fast pulse trains with short inter-pulse intervals. Despite some limitations, this experimental setup highlights the efficacy of cost-effective methodologies in public aquariums for initial bioacoustic research. These findings contribute to the early stages of acoustic characterization of coastal fishes in the western central Atlantic, emphasizing the value of passive acoustic monitoring for ecological assessments and conservation efforts. Moreover, this study opens new avenues for considering the acoustic environment as a crucial factor in the welfare of captive fish, an aspect that has largely been overlooked in aquarium management.

Six Pulse Type Segmented Thyristor Controlled Reactor with Fixed Capacitor for Reactive Power Compensation

This article presents a Six Pulse Type Segmented Thyristor Controlled Reactor (TCR) integrated with a Fixed Capacitor (FC) for reactive power compensation. The primary objective is to improve voltage stability and power factor in electrical networks, addressing issues related to reactive power imbalance and harmonic distortion. The proposed configuration combines the advantages of segmented TCR and FC, providing a flexible and efficient approach to reactive power management. The novelty of this work lies in the segmentation of the TCR, which enhances the dynamic control of reactive power by allowing more precise regulation and reduced harmonics compared to conventional TCR systems. This segmented approach also minimizes switching losses and thermal stress on thyristors, leading to enhanced reliability and longevity of the system. Additionally, the integration of a fixed capacitor optimizes the overall power factor correction, contributing to improved system efficiency. Key findings from simulation and experimental results demonstrate that the Six Pulse Type Segmented TCR with FC significantly reduces reactive power, stabilizes voltage levels, and effectively suppresses harmonics within permissible limits, adhering to IEEE standards. The system shows a marked improvement in power quality, making it a viable solution for industrial applications where reactive power control is critical. This innovative approach not only provides superior compensation characteristics but also offers a scalable and adaptable framework for modern power systems, highlighting its potential to enhance operational performance and energy efficiency in various electrical grids.

Incorporation of machine learning into multiple stripe seismic fragility analysis of reinforced concrete wall structures

This study proposes a novel procedure that incorporates machine learning (ML) into the multiple stripe analysis (MSA) approach to efficiently produce seismic fragility curves for reinforced concrete (R/C) shear walls in building frame systems. The proposed procedure aims to mitigate computational challenges associated with the original MSA approach. In this context, ML models were developed for predicting the failure probability of R/C walls subjected to ground motions based on a specified threshold of maximum interstory drift ratio (MIDR). Specifically, the result of each numerical analysis, taken as the output variable of the ML models, was classified as either “B” (Below) or “E” (Exceeding) to indicate whether the MIDR of R/C walls was below or exceeding the specified threshold. This binary categorization was then used to calculate the failure probability points, which are necessary to derive fragility curves per the MSA approach. Data for training and testing the ML models were generated from nonlinear time history analyses of 46 distinct R/C walls subjected to 1000 ground motions. The R/C walls varied in height from four to 40 stories, and the ground motions included far-field, near-field pulse, and near-field no-pulse types. Four well-established ML methods, including random forest (RF), extreme gradient boosting, light gradient boosting machine, and categorical boosting, were considered. The performances of the ML models were compared using a confusion matrix. Based on this comparison, the RF model was selected and incorporated into the proposed procedure. Subsequently, the proposed approach was demonstrated to create the seismic fragility function of a new R/C wall structure. This study highlights the potential of ML applications in optimization problems within the earthquake engineering domain.

Impact of a Pulse-Enriched Human Cuisine on Functional Attributes of the Gut Microbiome Using a Preclinical Model of Dietary-Induced Chronic Diseases.

Introducing grain legumes, i.e., pulses, into any food pattern effectively increases dietary fiber and other bioactive food components of public health concern; however, the impact depends on the amount consumed. Given the convergence of preclinical and clinical data indicating that intake of at least 300 g (1.5 cup) of cooked pulse per day has clinically observable benefit, the feasibility for a typical consumer was demonstrated by creation of a fourteen-day menu plan that met this criterion. This menu plan, named Bean Cuisine, was comprised of a combination of five cooked pulses: dry beans, chickpeas, cowpeas, dry peas, and lentils. As reported herein, the impact of each menu day of the fourteen-day plan on gut microbial composition and predicted function was evaluated in female C57BL/6J mice, a strain commonly used in studies of metabolic dysfunction-associated chronic diseases. We report that pulse-related effects were observed across a wide variety of food item combinations. In comparison to a pulse-free human cuisine, all pulse menu days enriched for a gut ecosystem were associated with changes in predicted metabolic pathways involving amino acids (lysine, tryptophan, cysteine), short-chain fatty acids (butyrate, acetate), and vitamins (B1, B6, B9, B12, K2) albeit via different combinations of microbiota, according to the PICRUSt2 estimates. The predicted metabolic functions correlating with the various pulses in the menus, indicate the value of a food pattern comprised of all pulse types consumed on a regular basis. This type of multi-pulse food pattern has the potential to enhance the taxonomic and functional diversity of the gut microbiome as a means of strengthening the resilience of the gut ecosystem to the challenges associated with the daily activities of living.

Probabilistic Prediction on Seismic Responses of a Long-Span High-Speed Railway Bridge Using BPINN

Efficient probabilistic prediction of seismic responses is crucial for assessing the seismic-resistant capability of long-span continuous girder high-speed railway bridges. Thus, a Bayesian physics-informed neural network (BPINN) is adopted to rapidly and effectively predict the probabilistic seismic responses of such bridges. The BPINN model combines deep learning and physics to improve the accuracy and consistency of predictions, while also quantifying the uncertainties using Bayesian inference methods. Various seismic excitations, including pulse, far-field and near-field types, are employed to probabilistically predict the seismic responses of the top of bridge pier. Evaluation metrics, including mean squared error and prediction interval coverage probability, are used to assess the deterministic and probabilistic estimates of BPINN. Results demonstrate that BPINN performs better in deterministic results for far-/near-field ground motions compared to pulse-like earthquakes, with most cases exhibiting a close approximation to the 95% confidence interval. The flexibility and adaptability of BPINN in handling different types of ground motions can provide valuable insights for assessing the seismic performance of such structures.

Research Progress on Saccharide Molecule Detection Based on Nanopores.

Saccharides, being one of the fundamental molecules of life, play essential roles in the physiological and pathological functions of cells. However, their intricate structures pose challenges for detection. Nanopore technology, with its high sensitivity and capability for single-molecule-level analysis, has revolutionized the identification and structural analysis of saccharide molecules. This review focuses on recent advancements in nanopore technology for carbohydrate detection, presenting an array of methods that leverage the molecular complexity of saccharides. Biological nanopore techniques utilize specific protein binding or pore modifications to trigger typical resistive pulses, enabling the high-sensitivity detection of monosaccharides and oligosaccharides. In solid-state nanopore sensing, boronic acid modification and pH gating mechanisms are employed for the specific recognition and quantitative analysis of polysaccharides. The integration of artificial intelligence algorithms can further enhance the accuracy and reliability of analyses. Serving as a crucial tool in carbohydrate detection, we foresee significant potential in the application of nanopore technology for the detection of carbohydrate molecules in disease diagnosis, drug screening, and biosensing, fostering innovative progress in related research domains.

Anodic oxidation by electrical power pulses for alachlor degradation

ABSTRACT This article explores the benefits of electrochemical oxidation in pulsed mode, using potential, current, and power pulses. While potential and current pulse electrochemical technology has been previously studied for wastewater treatment, no study has included power pulses until now. The objective of this work is to highlight the advantages of power pulses by applying this pulse type to the electrochemical oxidation of a probe molecule, alachlor. For this aim, the influence of operating parameters and the comparison of the different pulse modes were investigated and compared to the results obtained with the electrochemical oxidation of alachlor in continuous mode. The study shows that the best results were obtained with the power pulse electrochemical oxidation with 100% alachlor degradation after 180 min and a mineralisation yield of 38.3% after 240 min. These results were better than those reported in the literature for treatments with continuous current input using platinum electrodes. This new technique could be an effective and efficient way to treat contaminated water and reduce the pressure on freshwater reserves.

Supercontinuum generation by nonlinear polarization rotation mode-locked fiber laser with pulse type switchable

We report on the generation of a supercontinuum (SC) by nonlinear polarization-rotating (NPR) mode-locked fiber laser, which includes a pulsed switchable NPR mode-locked fiber laser, an Er-doped fiber amplifier, and high nonlinear fiber (HNLF). In the experiment, by adjusting the polarization controller (PC) angle and pump power, we obtained three different pulses. They are traditional soliton bunch pulses, the coexistence of soliton bunch pulses and square pulses, and multi-longitudinal mode noise like square pulses. All three pulses can generate SC with spectrum width be about of 1000 nm. We fixed the pump power in the laser and observed the influence of amplifier power on the spectrum width and output power of SC. The SC width of soliton bunch pulse reaches 950.9 nm, the SC of soliton bunch pulse and square pulse coexisting pulse is 1009.7 nm, and the SC spectrum width of multi-longitudinal mode noise like square pulse is 887.1 nm. Our results demonstrate the generation of SC with three types of switchable pulses, opening up possibilities for various application requirements.

Closed forms for spatiotemporal optical vortices and sagittal skyrmionic pulses

Abstract Spatiotemporal optical vortices (STOVs) are short pulses that present a vortex whose axis is perpendicular to the main propagation direction. We present analytic expressions for these pulses that satisfy exactly Maxwell’s equation, by applying appropriate differential operators to complex focus pulses with Poisson-like frequency spectrum. We also provide a simple ray picture for understanding the deformation of these pulses under propagation. Finally, we use these solutions to propose a type of pulse with sagittal skyrmionic polarization distribution covering all states of transverse polarization.

Organic Pulse Production: Exploring Opportunities and Overcoming Challenges

Pulses are an essential part of global human nutrition and sustainable agriculture, consisting of a range of leguminous crops like beans, lentils, and chickpeas. The growing demand for organic food has made organic pulse cultivation a viable means of satisfying this need while also fostering environmental stewardship and strengthening farm resilience. Increased biodiversity on farms, fewer chemical inputs, and better soil health are just a few benefits of growing pulses organically. Furthermore, organic pulses are well known for their high nutritional content, providing the human diet with the necessary fibers, proteins, and minerals. Farmers that grow pulses have a large market opportunity due to consumers’ increased demand for organic products. But growing organic pulses certainly has its share of difficulties. These include probable yield swings, vulnerability to pests and diseases, and restricted availability of seeds with organic certification. Furthermore, farmers may face operational and financial challenges throughout the shift from conventional to organic agricultural methods. Multiple parties must work together in order to overcome these obstacles and take advantage of the potential that comes with producing organic pulses. The development of hardy organic pulse types that are suited to a range of agroecological settings can be greatly aided by research. It is imperative for policymakers to enact laws and incentives that are conducive to the growth of organic pulse production and provide equitable market access for organic growers. Ultimately, organic pulse farming has enormous potential for both food security and sustainable agriculture. Organic pulse growers can play a major role in supplying the increasing demand for nutrient-dense, eco-friendly food while building strong, thriving farming communities by mitigating problems with innovative solutions and teamwork.