Number Of Pulses Research Articles

Modeling nanogratings erasure at high repetition rate in commercial optical glasses

Volume nanogratings (NGs) imprinted by infrared femtosecond laser in commercial optical glasses take the form of orientable subwavelength birefringent nanostructures, being composed of an assembly of nanopores. The existence of NGs strongly depends on the laser parameters and glass composition. Therefore, in this work, we tentatively model the erasure threshold of NGs in a pulse energy - repetition rate processing window. For this purpose, we combine i) a heat diffusion model to simulate the thermal treatment experienced by the glass upon laser irradiation, and ii) the Rayleigh-Plesset equation to take into account the evolution of a nanopore size during laser processing. We first determine a criterion for nanopores erasure, falling within a typical characteristic time of few tens of ns, in which the cooling of the last laser pulse absorbed by the material is progressively cooled. Then, considering a multiple pulse regime and the dependence of the deposited pulse numbers on the thermal treatment, the modeled NGs erasure threshold follows the experimental trend. Finally, considering a steady state regime for various repetition rates, and adjusting the energy deposition (absorption coefficient or beam waist) as a function of the pulse energy, the NGs existence window can perfectly match the experimental values.

Self-Powered Wearable Displacement Sensor for Continuous Respiratory Monitoring and Human-Machine Synchronous Control.

Flexible wearable electronic devices play a vital role in daily monitoring, medical diagnosis, and human-computer interaction, and such devices have a great demand for portability, integration, comfort, and self-power. In this study, a triboelectric nanogenerator integrated into a flexible chest belt is proposed as a displacement sensor to monitor the displacement and frequency of thoracic expansion. Based on three parallel interpolation electrode structures with phase differences, the Triboelectric Nanogenerators's(TENG) output signal pulse number can characterize the sliding displacement, with a resolution of more than 1mm and a durability of more than 700,000 cycles. Based on the flexible printed circuit processing technology, the volume of the sensor is less than 8.5cm3, and the weight is less than 3.2g, which improves the portability of the device. Based on wireless radio frequency technology, the collected signals are transmitted to the upper computer, and then the monitoring of respiratory physiological signals and the human-machine synchronous control of the ventilator are achieved within the overshoot of 1.5% and the control error of 5% through a simulation machine. This work provides a sensing method for daily and medical respiratory monitoring and demonstrates the enormous potential of frictional electric sensors in intelligent medical applications.

Low-noise soliton molecule generation with an in-phase controllable pulse number by third- and second-order dispersion compensation in an all-fiber erbium-doped oscillator: publisher’s note

Low-noise soliton molecule generation with an in-phase controllable pulse number by third- and second-order dispersion compensation in an all-fiber erbium-doped oscillator: publisher’s note

Pulsed Electric Field for Quick-Cooking Rice: Impacts on Cooking Quality, Physicochemical Properties, and In Vitro Digestion Kinetics

Pulsed electric field (PEF) is one of the emerging technologies that has been applied in many aspects of the food industry. This study examined the impacts of a PEF on the cooking quality, physicochemical properties, nutritional factors, and in vitro protein and starch digestion of two varieties of rice, including Jasmine 105 (white non-glutinous rice) and San Pa Tong 1 (white glutinous rice). Response surface methodology (RSM) and a three-level, three-factor Box–Behnken design were employed to assess the effects of the pulse number, electric field strength, and frequency on cooking time. The findings demonstrated that the number of pulses was a crucial factor influencing cooking time. Under optimal conditions (3347–4345 pulses, electric field strengths of 6–8 kV/cm, and frequencies ranging from 6 to 15 Hz), the rice cooking time was significantly reduced by 40–50% (p < 0.05) when compared to a conventional method. Moreover, PEF-treated rice showed a significant enhancement in in vitro protein and starch digestibility (p < 0.05), as well as retained a higher content of rapidly digestible starch. These results suggested that PEF treatment is a promising green technology for producing a novel quick-cooking rice with an improved eating quality.

A Simple 18‐Pulse Uncontrolled Star Rectifier by Adopting Dual Passive Injection Circuits at DC Side

ABSTRACTThis research introduces a simple 18‐pulse star rectifier, which is a combination of a conventional double‐star rectifier and two new passive injection circuits. The proposed passive injection circuits are constituted with a specially tapped interphase transformer (STIPT) and four diodes. The proposed passive injection circuits can simultaneously increase the step number of the input line current and the pulse number of the load voltage. The first passive injection circuit (FPIC) doubles the pulse number of the traditional double‐star rectifier converting it into an asymmetrical 12‐pulse star rectifier while the second passive injection circuit (SPIC) further converts the 12‐pulse star rectifier into 18‐pulse star rectifier. For tripling the pulse number of the double‐star rectifier, the STIPT requires to be designed optimally. For designing purpose, the proper tap ratios of the STIPT are determined depending on the minimum total harmonic distortion (THD) of the input line current. When designed optimally, the proposed rectifier simultaneously reduces the THD of the input line current and ripple of the output voltage with increasing pulses. In order to provide experimental validation for the theoretical evaluation, a laboratory prototype is constructed. The theoretical THD of the input line current is about 10.1%, whereas the experimental THD is about 5.42%.

Effects of Velocity Pulse-Like Ground Motions on the Seismic Failure Behavior of Masonry Minarets

ABSTRACT This research is motivated by post-earthquake observations of significant structural damage to minarets during the 2023 Kahramanmaraş earthquakes. It is thought that the near-fault velocity pulse-like ground motions played a crucial role in this phenomenon. Although the seismic performance of minarets has been extensively studied, including a large body of literature on numerical and experimental analyses, no attention has been paid to the seismic damage assessment of minarets subjected to strong velocity pulse-like ground motions. The present study aims to investigate the effects of near-fault strong velocity pulse-like ground motions with different velocities on the seismic failure behavior of masonry minarets. A 33-meter-high stone masonry minaret was selected for this purpose. Nonlinear behavior of masonry unit is modeled using Concrete Damage Plasticity (CDP). For the nonlinear analysis, three near-fault strong velocity pulse-like ground motions recorded during February 6, 2023, Kahramanmaraş earthquake (M7.7) and one non-pulse-like ground motion were selected. Displacements, strains, stresses and damage patterns in masonry minarets subjected to near-fault velocity pulse-like and non-pulse-like ground motions were obtained and thoroughly evaluated across different ground velocities. The velocity, the number of pulses and the pulse duration of velocity-pulse-like ground motions have a significant influence on the structural damage behavior of minarets. The results provide a detailed understanding of how minarets respond to different velocity pulse-like ground motion scenarios, offering valuable insights for the design, rehabilitation, and retrofitting of both new and existing minarets.

Low-noise soliton molecule generation with an in-phase controllable pulse number by third- and second-order dispersion compensation in an all-fiber erbium-doped oscillator

We report on the experimental results of high-order soliton molecule (SM) generation in an erbium-doped oscillator. The generation of 14 solitons with an average power of 48 mW, a pulse duration of 508 fs, a separation of 2.59 ps between pulses, and a repetition rate of 19 MHz at 1560 nm central wavelength was demonstrated. The stability of this generation was also evidenced by its low relative intensity noise (0.08% in the frequency range [10 kHz–1 MHz]), and a low Allan deviation of frequency repetition rate of 1.98⋅10−9 at an interval of 1 s (during 10 h of free-running measurements). Moreover, the accurate manipulation of SM order by changing the pump power was investigated; we showed the ability to generate with four, six, seven, nine, 10, 11, 13, and 14 pulses with high stable states between solitons. The change in the number of pulses occurred repeatably by increasing and decreasing the pump power, offering a stable source of a controllable number of pulses for potential applications in quantum computing.

Changes in Male Behavior in Response to Female Chemical Stimulus in an Understudied Arthropod Model

ABSTRACTIntraspecific sexual communication, crucial in reproductive interactions, often involves the interchange of signals like vibrations, visual signals, and chemical compounds like sex chemical cues. Within the arachnids, solifuges (“camel spiders”) are an understudied group in terms of the detection of chemical compounds during mate searching and sexual interactions. In solifugids, the malleoli, chemoreceptor structures located on the ventral side of legs IV, are putative structures capable of capturing chemical signals. Our study focused on chemical male perception of female cues in Titanopuga salinarum (Ammotrechidae), examining associated behavioral modifications and the role of malleoli. We analyzed alterations in the motion pattern (activity pulse) and specific behaviors performed by males in association with female chemical stimuli. Using experimental arenas, we exposed males to female chemical cues stimuli similar to those available at the field. Stimuli comprised females (F) and cuticular extracts (CE), with corresponding controls. Males with intact malleoli (N = 26 with F, N = 20 with CE) were compared to those with malleoli removed (N = 21 with F, N = 17 with CE). We found partial evidence that males detect chemical cues of females deposited on the substrate. We observed no differences in the duration and number of the activity pulses spent in the zones with and without stimuli in any of the groups analyzed. However, the males exhibit significant changes in locomotion patterns in response to female chemical cues, suggesting a behavioral response to these stimuli. This finding suggests that the males of this species detect the female chemical cues and modify their behavior, and can quickly gather the necessary olfactory information where the stimulus is located. In addition, we found a possible condition‐dependent regime for the detection of female cues by males, which would be expected from life‐history characteristics of T. salinarum. Our findings prompt discussion from a sexual selection perspective, suggesting the importance of chemical communication in intraspecific interactions in this elusive but fascinating animal model.

Ultrafast thermal modulation dynamics during ripple formation induced by a femtosecond laser multi-pulse vortex beam

Abstract This work theoretically investigated the ultrafast thermal modulation dynamics during early formation of ripples on an Au film induced by femtosecond laser multi-pulse vortex beam irradiation. An extended two-temperature dynamics model that comprehensively considers optical interference modulation for the formation of seed ripples, transient reflectivity and non-equilibrium thermal transfer was self-consistently built to predict high-contrast ripple formation. The two-dimensional evolution of electron and phonon temperature modulations during ripple formation in a high non-equilibrium state of Au film were obtained via femtosecond laser multi-pulse vortex beam irradiation. It was revealed that ripple contrast can be significantly amplified by shortening the laser wavelength, increasing the pulse number, or enlarging the laser fluence of the vortex beam. Moreover, the electron–phonon coupling time during ripple formation is fully explored in detail. This study provides valuable insights into optimizing laser parameters for controlled high-contrast ripple formation on Au films.

Selective Ablation and Laser-Induced Periodical Surface Structures (LIPSS) Produced on (Ni/Ti) Nano Layer Thin Film with Ultra-Short Laser Pulses

The interaction of ultra-short laser pulses (USLP) with Nickel/Titanium (Ni/Ti) thin film has been presented. The nano layer thin film (NLTF), composed of ten alternating Ni and Ti layers, was deposited on silicon (Si) substrate by ion-sputtering. A single and multi-pulse irradiation was performed in air with focused and linearly polarized laser pulses. For achieving selective ablation of one or more surface layers, without reaching the Si substrate, single pulse energy was gradually increased from near the ablation threshold value to an energy value that caused the complete removal of the NLTF. In addition to single-pulse selective ablation, the multi-pulse USLP irradiation and production of laser-induced periodic surface structures (LIPSSs) were also studied. In the presented experiment, we found the optimal combination of accumulated pulse number and pulse energy to achieve the LIPSS formation on the thin film. The laser-induced morphology was examined with optical microscopy, scanning electron microscopy, and optical profilometry. To interpret the experimental observations, a theoretical simulation has been performed to explore the thermal response of the NLTFs after irradiation with single laser pulses.

Effect of High Heat Flux of Helium and Hydrogen Plasma Jet on the Material Properties of Piezoelectric PZT-Ceramics

A set of experimental and measurement techniques to study the influence of a plasma jet on the main material parameters of piezoelectric ceramics has been presented. A series of plasma experiments has been carried out using a pulsed plasma jet system. It allows of a metered-dose exposure to plasma of different composition and fluence with a constant particle flux density of 1021/m2, energy flux density of 0.1 MJ/m2 and average particle energy of 100–200 eV in a pulse duration of 15 μs. The study of the effects that a repeated exposure to an extreme heat flux of helium and hydrogen plasmas has on the near-surface layer structure and basic material parameters of mass-produced piezoelectric ceramic samples has been presented. The main result of the research is an experimental confirmation of the surface micro-structuring starting after just a few cycles of plasma exposure while only a slight decrease of the main material parameters as well as the preservation of polarization has been observed for two types of different compositions of PZT-ceramics. A further increase in the number of exposure pulses leads to practically no change of main material parameters of both ceramics, even showing a tendency for recovery instead.

Artificial photoelectric synaptic devices with ferroelectric diode effect for high-performance neuromorphic computing

With the rapid advancement of artificial intelligence and machine learning, the demand for neuromorphic computing systems has intensified. High-performance artificial synaptic devices are crucial to achieving this objective. Ferroelectric diode artificial synaptic devices were prepared using aluminum-doped BaTiO3 (BTAO) thin films by a low-cost sol-gel method. These devices mimic the basic properties of biological synapses, such as long-term plasticity (LTP) and short-term plasticity (STP), under electrical stimulation. Additionally, the devices exhibit an excellent UV light response, enabling the transition from STP to LTP by adjusting the light pulse intensity, width, and number of pulses. Aluminum doping significantly enhances the ferroelectricity of BaTiO3 films, increasing the Pr from 2.31 µC/cm² to 9.08 µC/cm². By modulating the Schottky barrier through polarization, the BTAO films exhibit a switchable diode effect, which facilitates fine-tuning of the synaptic connection strength while maintaining synaptic stability. Recognition accuracies of 97.32 % for the MNIST dataset and 87.48 % for the Fashion-MNIST dataset were achieved by convolutional neural network simulations. These results suggest new possibilities for brain-like processing with ferroelectric diodes.

Influence of electron radiation of spring barley seeds on phytopathogenic microflora

Under the conditions of a model pot experiment, the effect of electron irradiation on the phytopathogenic microflora of plant roots and leaves was studied. The studies were carried out on spring barley seeds of the Vladimir variety (reproduction 1), affected by helminthosporiosis (pathogen Bipolaris sorokiniana Shoem.), (natural infectious background). This pathogen causes root rot and leaf spot. The grain was irradiated using a wide-aperture electron accelerator “Duet” with a mesh plasma cathode and the output of the generated beam of a large cross-section into the atmosphere in doses of 1, 2, 3, 4 and 5 kGy. The total administered dose was increased by changing the number of pulses. The radiation dose rate was 100 Gy/pulse, the electron energy was 130 keV (mode 1) and 160 keV (mode 2). The depth of dose absorption did not exceed 300 μm. Based on the conducted studies on the effect of electron irradiation on root rot (pathogen Bipolaris sorokiniana) of spring barley, it was noted that in the tillering and heading phases, when irradiating seed material with a dose of 2 kGy in mode 1 (130 keV), the disease incidence and prevalence decreased by more than 1.5 times compared to the non-irradiated control. In the phase of full grain maturity, the highest value of root infestation (45–50%) and prevalence (95–100%) of Bipolaris sorokiniana were recorded, but statistically significant differences between the irradiated variants and the control were absent. The records of the damage of vegetative plants showed that in the tillering phase, for all irradiation variants in mode 1, the degree of damage to leaves 1–3 increased by 23% compared to the control, and in the heading phase, the degree of damage to the upper leaves (1–3) exceeded the control when irradiated at doses of 2–5 kGy (mode 1) and 1–5 kGy (mode 2) – 2.1–2.8 times for 1 leaf, 1.9–2.0 times for 2 leaves and 1.2 times for 3 leaves.

Optical pulse generation with programmable positions in an actively mode-locked optical cavity.

A novel, to our knowledge, approach for generating optical pulses with programmable positions in an actively mode-locked (AML) optical cavity is proposed and experimentally demonstrated. In the AML, active mode locking occurs when the cavity gain exceeds one, and the cavity round trip time equals integer multiples of the repetition period of the electrical driving signal. The generated optical pulses are present at the positions where the optical cavity operates at its maximum transmission points. By periodically controlling the cavity gain with the driving signal, the maximum transmission points can be manipulated using a periodic arbitrary waveform, allowing the positions of the generated optical pulses within one round trip time to be programmed. Thanks to the superposition of the circulating optical field within the optical cavity, the pulse width of the generated pulses can be greatly compressed. In a proof-of-concept experiment, optical pulses with programmable pulse numbers, pulse intervals, and pulse position distributions in one period are generated by programming the driving signals. Optical pulse compression is also successfully verified. Optical pulses with an approximate 34-ps pulse width, ultra-low pulse interval (about 200 ps), and linear positional distribution are achieved.

Arrhythmogenicity of monophasic and biphasic PFA waveforms in a porcine model.

The potential risk of inducing ventricular arrhythmias was explored by employing pulsed field ablation (PFA) through the administration of both monophasic and biphasic waveform deliveries. PFA was applied to specific locations in the right ventricle (RV, n = 5 sites) in swine (n = 2), utilizing identical settings with consistent amplitude, pulse width, and a number of pulses for both monophasic and biphasic waveforms. PFA deliveries were precisely timed in 10-ms intervals across the entire T wave. Using monophasic waveforms, ventricular fibrillation (VF) was induced 7/7 times when PFA pulses were delivered during the T wave. Biphasic waveforms resulted in no ventricular arrhythmias when PFA was delivered across the entire duration of T wave. Our findings indicate that VF can be consistently induced with monophasic pulse waveforms, but not with biphasic pulse waveforms in a porcine model.

Improving the thermochromic performance of VO2 films by embedding Cu-Al nanoparticles as heterogeneous nucleation cores in the VO2/VO2 bilayer structure

VO2-based films show great potential applications in thermochromic smart windows. However, enhancing luminous transmittance (Tlum) while maintaining high solar modulation ability (ΔTsol) remains a formidable challenge. Here, we present a novel VO2/Cu-Al nanoparticles (NPs)/VO2 composite film structure, seamlessly integrating Cu-Al bimetallic NPs within VO2 films by pulsed laser deposition on alkali-free glass substrates. The content of Cu-Al NPs in the composite films is controlled by the pulse number (Np) applied to the Cu-Al alloy target. X-ray diffraction results indicate that the crystallinity of VO2 films is significantly enhanced by the incorporation of an appropriate amount of Cu-Al NPs. The SEM characterization results revealed that the particle size of VO2 composite films initially increases to approximately 131 nm and subsequently decreases to around 120 nm as Np increases, with a concurrent transition in particle shape from quasi-circular to elongated. The Tlum and ΔTsol of the resulting composite films were dramatically improved to 71.6 % and 9.5 %, respectively, when Np was 300. These enhanced thermochromic properties are attributed to the localized surface plasmon resonance (LSPR) of the VO2 particles. This research opens up a promising avenue for the convenient production of customized high-quality VO2 films tailored for smart window applications.

Efficacy and tolerability of extracorporeal shock wave therapy in patients with plantar fasciopathy: a systematic review with meta-analysis and meta-regression.

Plantar fasciopathy (PF) is a common musculoskeletal condition characterized by heel pain and functional impairment. Extracorporeal shock wave therapy (ESWT) has gained increasing interest in the treatment of PF, but the optimal ESWT program is still debated. Therefore, this systematic review with meta-analysis and meta-regression aimed at providing a comprehensive assessment of the efficacy and tolerability of ESWT in PF management. Randomized controlled trials (RCTs) published until February 2023 were systematically searched on PubMed/MEDLINE, Scopus, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and PEDro. Studies assessing adult patients with PF treated with ESWT were considered. The primary outcome was the tolerability of ESWT, measured by treatment adherence, dropouts, and safety. Secondary outcomes were pain intensity and functional outcomes. Meta-analysis and meta-regression were performed to examine the relationship between ESWT program characteristics and treatment outcomes. The quality of included studies was assessed using the Jadad scale and the Cochrane risk-of-bias tool. Eleven studies met the inclusion criteria and were included in the analysis. Our findings showed that ESWT is effective in reducing pain intensity assessed by Visual Analogue Scale [focal-ESWT: -2.818 (SE 0.803, -4.393, -1.244; P< 0.0001; radial-ESWT: -3.038 (SE 0.428, -3.878, -2.199; P<0.001)]. Meta-regression analysis indicated a positive relationship between specific ESWT parameters (frequency, number of pulses, energy flux density and frequency, and number of pulses, pressure) and pain intensity (all P<0.05) and dropout (all P<0.05). ESWT seems to be an effective and tolerable treatment for PF, albeit the peculiarity of parameters might affect both the efficacy in pain relief and the adherence to the treatment. Physicians should consider individual patient characteristics when selecting the ESWT parameters for PF treatment. Further high-quality studies are warranted to establish the optimal ESWT protocol to treat PF.

Enfoque multitareas implementado en una minicomputadora para el control y monitoreo de un motor a pasos industrial

This paper presents the implementation of the multitasking approach on a Raspberry Pi single board minicomputer, with experimental results, of the control and monitoring of an industrial type Nema 34 stepper motor through a user interface that allows the configuration of the control operation and data visualization to interact with the physical devices. One of the tasks consists of generating a pulse width modulation that is sent to the DQ860HA driver to rotate the stepper motor considering 400 pulses per revolution, while the second task simultaneously counts the number of pulses produced by an encoder with a resolution of 100 pulses per revolution, which is coupled to the motor shaft. The use of low-cost computer equipment and open-source software makes the presented development can be considered as a frugal technology application for the control and monitoring of an industrial system, with experimental results that validate the correct operation of two tasks that must be executed simultaneously.

Triangular Carrier Based Synchronous PWM for Operating High Power IM Drives at Odd Non-Triplen Pulse Numbers

Triangular Carrier Based Synchronous PWM for Operating High Power IM Drives at Odd Non-Triplen Pulse Numbers

Colloidal Quantum Dots‐Based Photoelectrochemical‐Type Optoelectronic Synapse

AbstractCurrent artificial neuromorphic systems are mainly constructed using solid‐state optoelectronic synaptic devices, limiting their potential artificial intelligence applications in liquid medium. Here, colloidal CuInGaSe/ZnSe quantum dots (QDs) with environment‐benign feature and broad visible light absorption are prepared to fabricate a photoelectrochemical (PEC)‐type optoelectronic synaptic device operating in aqueous electrolyte, enabling unique biological synaptic behaviors including paired‐pulse facilitation (PPF), short‐term plasticity (STP), long‐term plasticity (LTP) and learning‐forgetting‐relearning process when simulated by optical pulses with various wavelength, pulse number, frequency, power density, and applied voltage. These results demonstrate the feasibility of building PEC‐type optoelectronic synapses using colloidal QDs, paving the way to realize available optoelectronic synaptic devices for prospective underwater artificial intelligence technology.