This paper presents a silicon photomultiplier (SiPM) based light detection and ranging (LiDAR) system that enables three-dimensional imaging in low signal-to-noise ratio (SNR) detection scenarios, where the number of laser echo photons is comparable to the number of noise photons. We establish a theoretical model for SiPM response to non-repetitive frequency multi-pulse sequences in the low SNR detection scenarios, combining pseudo-random pulse encoding with threshold discrimination and matched-filtering technology. Experimental results demonstrate that compared with traditional SiPM-based LiDAR methods, our approach achieves effective 3D imaging with clearer contours, faster response speed, and higher robustness, enabling practical applications in low SNR detection scenarios.

Background: Despite the clinical significance of circumcision, traditional suturing is frequently compromised by intraoperative bleeding and lengthy recovery periods. While high-frequency electric welding (HFEW) presents a compelling alternative, its utility in foreskin removal procedures remains unexplored. Methods: Employing freshly excised human foreskin tissues, this study simulated the circumcision procedure to benchmark HFEW against standard suturing techniques. Critical performance metrics, encompassing tensile integrity, thermal injury scope, and operative efficiency, were rigorously quantified. Results: HFEW demonstrated exceptional time efficiency, averaging 2.01 ± 0.9 min—a 77.02% reduction relative to conventional suturing (p < 0.001). However, mechanical testing revealed disparities in tissue adhesion; the HFEW cohort recorded lower forces for initial tearing (4.42 ± 1.02 N) and complete rupture (6.15 ± 1.65 N) compared to the superior tensile resistance of the suturing group (7.91 ± 3.26 N and 14.22 ± 6.91 N, respectively). Conclusions: Although HFEW yields comparatively lower tensile strength, its remarkable operational efficiency positions it as a viable technical innovation for circumcision. These preliminary findings support the pursuit of further in vivo investigations to confirm its clinical applicability.

High-frequency electric welding (HFEW) technology holds great promise for small intestine end-to-end anastomoses, but existing energy generators lack feedback mechanisms to quantify energy transfer and welding strength. This study proposes the dynamic impedance ratio (eta = Rf/Rmin) as a novel feedback parameter to standardize intraoperative assessment while mitigating individual variability. Systematic investigations were conducted through ex vivo porcine small intestine end-to-end welding experiments, analyzing the effects of compression pressure (50 to 400 kPa), voltage (40 to 60 V), and welding duration (10 to 20 s) on dynamic impedance. A short pulse signal measures how mechanical pressure affects tissue impedance. Under 150 to 350 kPa, impedance drops to 40% to 70% of its initial value. Results demonstrated that compression pressure reduced initial impedance by decreasing tissue thickness, while voltage and duration modulated dynamic impedance through thermal denaturation and dehydration. eta shows a strong positive correlation with burst pressure, effectively predicting weld strength. A higher eta indicates greater burst pressure, and when eta >= 2, the burst pressure test achieves a 100% success rate. As a predictor of welding strength, dynamic impedance ratio can predict weld strength without destroying the anastomosis tissue, which has wide application in the future. It will further improve the accuracy of energy regulation and further promote the use of HFEW in clinical applications.

Nonviral intracellular delivery based on pulsed-electric-field-induced electroporation is one of the most effective and widely used platforms in basic biological and biomedical research. However, the conventional bulk electroporation technique has exhibited limited performance in improving delivery efficiency with a single type of pulse, especially for in vivo small interfering RNA (siRNA) delivery. Pulse modulation has been confirmed effective in facilitating intracellular delivery. Nonetheless, pore evolution and regulation during and after electric exposure plays an essential role in the effective intracellular delivery of molecules with variable sizes. Here, we propose a progressive electroporation (PEP) strategy on the basis of multiple-pulse combination, which decouples the perforation process and delivery process compared to conventional bulk electroporation, efficiently improving delivery efficiency with regulation of the perforated pores. We demonstrated an important correlation between delivery efficiency enhancement and delayed pore resealing by quantitative investigations. The performance of this disruption-and-field-enhancement method also showed delivery advantages over conventional chemical systems. Moreover, we validated the improvement for siRNA knockdown efficacy in vivo. Overall, PEP helps provide a unique insight into improving intracellular delivery, by regulating pore dynamics rather than just inducing perforation. This strategic advancement of PEP may pave the way for the development of advanced wearable delivery systems with reduced energy consumption.

Multilayer ceramic capacitors (MLCCs) are widely used in power electronics. Because paraelectric and ferroelectric material are non-magnetic dielectrics, B-field effects are typically ignored in datasheets and design consideration. This letter reveals a significant, previously undocumented phenomenon: B-fields cause substantial high-frequency impedance variation in MLCCs, with observed changes exceeding 43% under B-fields up to 491 mT. Supplementary material includes all the design files for the measurement kit and all the raw data to ensure reproducibility. Raman spectroscopy and microstructure were employed to characterize the material composition and physical structure of the MLCCs.

Cross-correlation wind LiDAR estimates wind speed by tracking advected aerosol-backscatter texture, enabling compact, cost-effective systems using intensity returns only. We evaluate silicon photomultiplier (SiPM) processing for this task using a dual-beam, single-receiver architecture by comparing two in-gate intensity estimators: peak amplitude and pulse area. A Monte Carlo SiPM response model is used to compare the two estimators at the device-readout level in the linear-counting regime, and indoor fog-tunnel experiments are used separately to evaluate wind-retrieval performance at the system level. Over the tested (Uref,N) plane, it achieves a lower mean relative retrieval error (8.75% versus 9.81%) and a larger fraction of operating points below 10% relative error (74.18% versus 62.64%). Under the tested near-linear operating conditions, these results provide quantitative guidance for observable selection in SiPM-based correlation wind retrieval and support the feasibility of compact, fixed-range implementations.

High-power, compact, built-in Penning negative hydrogen ion source has been widely used in particle accelerator applications. But the problem of its short operating life has been an issue, with cathode mass loss being the main factor affecting its life. The material lost from the cathode will condense on the anode wall and will flake off under alternating heat and cold. The flaking material is directed from the cathode to the anode under the action of an electric field, and when the debris is too large it will short-circuit the cathode and anode directly. To solve this key problem, it is necessary to study the specific causes of cathode mass loss, and optimize the operation methods and design ideas of the ion source through these causes. In this paper, the cathode mass loss mechanism was investigated. It is considered that the cathode mass of this ion source is mainly lost through the evaporation process during the large arc current operation under the high purity gas environment. And several optimization measures are proposed in the operation and design of the equipment.

BACKGROUND:This study aimed to comparatively evaluate the tissue healing characteristics of High-Frequency Electric Welding (HFEW) versus conventional suture techniques in intestinal side-to-side anastomosis using an animal model. MATERIALS AND METHODS:Intestinal side-to-side anastomoses were performed in New Zealand White rabbits using HFEW and hand-sewn techniques. Intraoperative assessment focused on procedure duration, hemostasis, and immediate anastomotic strength. Postoperative monitoring tracked vital signs, physiological parameters, healing progression (assessed via burst pressure), histopathological features, and inflammatory cell infiltration. RESULTS:HFEW application reduced surgical duration and postoperative bleeding. Healing progression was comparable between HFEW and Suture groups. At 1 week postoperatively, vital signs and tissue strength normalized in experimental animals, with necrotic tissue replaced by regenerated tissue; Suture group specimens exhibited elevated inflammatory cell infiltration. By week 2, tissue strength further improved, inflammation subsided, and tissue morphology advanced. At 4 weeks, pathological structures in both HFEW and Suture groups closely resembled normal tissue. Compared with sutures, HFEW has advantages in terms of operating time and blood loss. During the postoperative healing phase, HFEW can effectively reduce the inflammatory response and accelerate healing. CONCLUSIONS:Postoperative healing with HFEW-based intestinal repair demonstrates comparability to manual suturing, while exhibiting reduced complication rates - offering residue-free foreign body anastomosis solution for laparoscopic surgery.

This study proposed a dual-wavelength coaxial light detection and ranging (LiDAR) system leveraging the GaN transparent detector (GaN-TD), which is sensitive to violet light, while maintaining transparency to near-infrared (NIR) radiation. We employed modulated high-frequency pulsed NIR waves and fully modulated sinusoidal violet signals for precise target detection. Our system maintained high measurement precision, achieving millimeter-level precision at a 3.5-m range. The integration of scanning galvanometers into the coaxial configuration enabled the acquisition of high-accuracy distance images at 1.2  m. This research validated the feasibility and benefits of GaN-TD in dual-wavelength LiDAR systems, significantly advancing dual-wavelength LiDAR technology.

Nanocrystalline materials are known for their high magnetic permeability and saturation magnetization, making them highly desirable for magnetic components. However, their low first resonant frequency ($f_{R}$), typically below 1 MHz, limits their use in high-frequency applications. This paper proposes a novel structure combining stacked infinite split magnetic cores, and sub-micrometer coating to enhance the resonant frequency without compromising magnetic performance. By reducing parasitic capacitance and improving the distribution of electric and magnetic fields, the proposed design significantly boosts the high-frequency impedance of nanocrystalline inductors.

Near-field radiation and parasitic inductance are key challenges for silicon carbide (SiC) mosfets. Current packaging techniques aiming at reducing inductance primarily focus on minimizing the commutation loop area, but these methods require complex layouts, routings, and manufacturing processes. Based on the physical principle that inductance is determined by the integral of the magnetic energy density, this manuscript proposes using copper shielding to induce eddy currents, thereby reducing the near-field magnetic radiation energy. The energy reduction further decreases parasitic inductance. Simulations and experiments indicate that for TO-247, the method can reduce inductance by 56.69% (from 23.39 to 10.13 nH) and radiation by 94.75% (from 13.16 to 0.69 mu T). Furthermore, using single-layer direct-bonded copper the proposed method can reduce inductance by 81.85% (from 2.81 to 0.51 nH) and radiation by 76.12% (from 13.16 to 0.69 mu T). The multimedia folder has included all the critical data, including the package designs, printed circuit board (PCB) designs, simulation files, and experimental raw data.

This letter presents an embedded current sensing (ECS) method to address the critical challenges in light-current-voltage (LIV) testing under nanosecond-pulsewidth and high-peak-power conditions. The conventional LIV testing method is mainly limited by the accuracy of current measurement at high di/dt. The proposed ECS method leverages an innerlayer printed circuit board (PCB) trace coupled with the parasitic inductances of the power loop, and combines with correction mechanisms to convert transient current variations into measurable induced voltages. Experimental validation demonstrates the method's capability to reconstruct current waveforms with peak currents approaching 70 A and pulsewidths as narrow as 5.8 ns, surpassing traditional shunt resistor method. Furthermore, the developed LIV test platform establishes a foundational framework for reliable characterization of high-power laser devices. This work bridges the validation and testing gap for next-generation optoelectronic devices operating in high-speed, high-current regimes.

To investigate the effect of high-frequency electric welding (HFEW) on intestinal tissue healing, we performed end-to-end anastomosis experiments in New Zealand rabbits. Within one week post-surgery, animals exhibited normal vital signs, replaced necrotic tissue with healthy collagen, and showed improved tissue strength while inflammation decreased. By day 60, tissue pathology and function fully recovered, resembling normal tissue. Healing at the anastomotic site occurred in three phases: immediate adhesion, inflammation, and remodeling, with macrophages crucial for phagocytosis and regeneration of necrotic tissue. This study enhances understanding of HFEW’s healing mechanisms and supports further preclinical investigations.

Due to the natural barrier of skin structure, traditional topical drug utilization for skin disease management has been severely constrained by low bioavailability. While current microneedle (MN)-based systems confront challenges related to therapeutic efficacy, penetration depth, and delivery precision, they offer considerable promise as minimally invasive platforms. To address these limitations, electric stimulus (ES) has been strategically integrated as a programmable external trigger within microneedle patches, enabling spatiotemporal control over drug release kinetics. This review systematically delineates recent advancements in ES-assisted microneedle systems for managing dermatological conditions, highlighting their dual capacity to enhance transdermal permeability while minimizing systemic toxicity through localized delivery, in alignment with emerging trends in functional integration and device miniaturization. This encompasses a comprehensive analysis of the regulatory role of ES, strategic selection of power supply modules, and the rational design of microneedles in conjunction with their corresponding drug-loading strategies. Guided by the Three I Principles (Integrated-Intelligent-Individualized), future developments should focus on creating closed-loop systems with embedded biosensors for real-time biomarker monitoring, implementing AI-driven adaptive dosing algorithms, and developing modular microneedle arrays. This paradigm shift towards patient-centered care will require cross-disciplinary convergence of flexible electronics, biocompatible energy harvesters, and precision medicine approaches to accommodate personalized treatment regimens.

Drug delivery plays a crucial role in both in-vitro and in-vivo biomedical applications. The complexity of the in-vivo conditions, such as cell-to-microenvironment and cell-to-cell interactions, presents challenges for effective delivery at the tissue and organ level. Various techniques have been developed to improve the delivery efficiency, ranging from physical assistance to biochemical carriers. Of which, combined electric pulses have been successfully employed to enhance the delivery in vivo, though the mechanisms of this process remain inadequately understood. In this study, the improvement on the molecule distribution and progressive delivery dynamics was elucidated in a 3D-cultured spheroid model using modulated electric field, which leveraged an optimized pulse combination of high voltage, short duration pulses (HSP) and low voltage, long duration pulse (LLP). The results demonstrated that modulated electric pulses (MEP strategy) promoted the intra-spheroid distribution and accumulation of molecules though transient delivery was not observed during pulse implementation. The roles of different pulse components were investigated which showed synergistic effects of reversible membrane electroporation and temporary disturbance of intercellular junction proteins, like ZO-1 and E-cadherin. The oriented and asymmetric motion of charged molecules was regulated as well by using LLP. Besides, we validated the enhancement over molecules with different sizes and charges. These findings may provide helpful perspectives for optimizing drug delivery in more complex biological systems and realistic delivery environments.

In this research we proposed a pulse-driven VCSEL array collimation model, termed the Virtual Line Light Source, designed for beam shaping extended Gaussian-like sources with a single lens. The technique employed for determining the lens surface area involved the utilization of a multi-channel peak-hold circuitry for measurement. The diameter of the lens was precisely regulated by the coordinates of the initial reference points. Virtual line source ray tracing simulated the target's spot size and intensity. MATLAB computations, corroborated by ZEMAX validations, demonstrated a 15 % reduction in the divergence angle compared to the Simultaneous Multiple Surface method. The model also achieved a 0.6 m x 0.6 m uniform spot for a 1.7 mm VCSEL array at 10 m, advancing cost-effective collimation techniques.

The use of high-frequency electric welding technology for intestinal end-to-end anastomosis holds significant promise. Past studies have focused on in vitro, and the safety and efficacy of this technology is uncertain, severely limiting the clinical application of this technology. This study investigates the impact of compression pressure, energy dosage, and duration on anastomotic quality using a homemade anastomosis device in both in vitro and in vivo settings. Two hundred eighty intestines and 5 experimental pigs were used for in vitro and in vivo experiments, respectively. The in vitro experiments were conducted to study the effects of initial pressure (50–400 kpa), voltage (40–60 V), and time (10–20 s) on burst pressure, breaking strength, thermal damage, and histopathological microstructure of the anastomosis. Optimal parameters were then inlaid into a homemade anastomosis and used for in vivo experiments to study the postoperative porcine survival rate and the pathological structure of the tissues at the anastomosis and the characteristics of the collagen fibers. The anastomotic strength was highest when the compression pressure was 250 kPa, the voltage was 60 V, and the time was 15 s. The degree of thermal damage to the surrounding tissues was the lowest. The experimental pigs had no adverse reactions after the operation, and the survival rate was 100

In power converters with high switching frequency, drive losses constitute a significant portion of the overall power losses. Resonant gate drivers can reduce drive losses, thereby enhancing the efficiency. However, resonant drivers suffer certain challenges: parameter drifts lead to the mismatch between the resonant frequency and the control frequency, and this mismatch can cause gate-to-source voltage overshoot. Moreover, the resonant driver is susceptible to external interference. This paper proposes a resonant circuit structure and control timing scheme aimed at overcoming these limitations. By incorporating a half-bridge clamp circuit, the proposed design achieves voltage clamping, thereby insulating the system from disturbances caused by mains power fluctuations. When there is a mismatch in resonant frequencies, the strategy employs a combination of hardware circuit diodes and control system timing to prevent overvoltage issues. Additionally, the utilization of MOSFETs minimizes the loss caused by prolonged current flow through body diodes, further reducing the resonant driving losses. Simulations have demonstrated the system’s stability under varying resonant parameters and its effective anti-interference capabilities in voltage clamping. Experiments achieved a power saving of 83.3% at a 1 MHz operating frequency. Both simulations and experimental validations confirm the feasibility of the proposed solution, its effectiveness in interference suppression, handling of resonant mismatches, and its role in further augmenting power conservation.

The parasitic capacitance of magnetic components, i.e., inductors and transformers, are crucial, because it dominates the high-frequency impedance, causes voltage / current spikes, and arouses electromagnetic interference issues. The existing methods characterize capacitance from all five parts (turn-to-turn, layer-to-layer, winding-to-magnetic core, winding-to-electrostatic screen, and interwinding). However, the calculated results are always less than the measured capacitance, especially for the inductors with few winding turns. This article discovers another mechanism of the parasitic capacitance caused by dB/dt. It points out that a time-varying magnetic field also generates an electric field, which leads to parasitic capacitance, and proves that this capacitance dominates the first resonant frequency (denoted by f(R)) of the inductors with few winding turns. The factors related to the capacitance and the f(R) are analyzed. The proposed theoretical analysis is validated by numerous simulations and experimental results. All the simulations are included in the multimedia folder.