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BACKGROUND: High-power short-duration (HPSD) ablation has emerged as an alternative to conventional standard-power long-duration (SPLD) ablation. We aim to assess the efficacy and safety of HPSD versus SPLD for atrial fibrillation (AF) ablation. METHODS: A systematic review and meta-analysis of randomized controlled trials (RCTs) retrieved from PubMed, WOS, SCOPUS, EMBASE, and CENTRAL were performed through August 2023. We used RevMan V. 5.4 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD) with a 95% confidence interval (CI). PROSPERO ID: CRD42023471797. RESULTS: We included six RCTs with a total of 694 patients. HPSD was significantly associated with a decreased total procedure time (MD: -22.88 with 95% CI [-36.13, -9.63], P = 0.0007), pulmonary vein isolation (PVI) time (MD: -19.73 with 95% CI [-23.93, -15.53], P

This paper presents the design and characterization of a solid-state power combining amplifier (SSPA) that operates within the full uplink frequency band of the Q/V-band (46.4 ~ 51.5 GHz), in which the power stage has been implemented by corporately combining 16 GaN amplifier monolithic microwave integrated circuits (MMICs) designed by CETC-13 Institute in a WR-19 waveguide. The SSPA is featured by more than 40W saturated output power with power added efficiency (PAE) of 12%, 20W output power with associated third-order intermodulation (IMD3) and spurious rejection better than 24 dBc and 65 dBc, respectively. The amplifier design employs a modular architecture where the amplifier, bias circuit, control circuit, and heat sink are fabricated independently, providing significant system flexibility. Modular amplifiers can be premade and reserved in case any malfunctioning amplifier needs to be replaced. To the best of the authors' knowledge, this SSPA is a significant improvement over all other SSPAs operating in this band. [ABSTRACT FROM AUTHOR]

This paper uses the non-integer ratio coaxial line impedance transform matching method to design a wideband RF power amplifier. The motivation for the research stems from the limitations of the fixed conversion ratio of traditional impedance converters at RF frequencies and the challenges of low-frequency performance degradation. A fixed conversion ratio and low-frequency performance often limit traditional impedance matching methods. The model enables flexible and efficient wideband impedance matching, covering a wide frequency range of 2–650 MHz. The results show that the power amplifier has an output power of more than 48.5 dBm, a gain of more than 16 dB, and a drain efficiency (DE) of more than 55% in the frequency band range of 2–650 MHz, which is superior to similar designs in terms of low-frequency performance and bandwidth. [ABSTRACT FROM AUTHOR]

A high‐power white laser source is prepared by using a 455 nm blue laser to excite YAG:Ce ceramics. To achieve high‐power output, a water‐cooling device is used to reduce the operating temperature of ceramics. The luminescence properties of laser‐excited phosphor ceramics are studied under different blue excitation power and different irradiation time. The experimental results show that the luminous flux of phosphor ceramics excited by the blue laser increases linearly with the increase of blue laser power, depending on the heat dissipation of the water‐cooling device. When the blue laser power increases to 73.1 W, the phosphor ceramics do not reach the luminescence saturation state. The luminous flux of phosphor ceramics excited by 73.1 W blue laser is stable within 60 min. The maximum luminous flux is 8094 lm, and the maximum working temperature of the ceramics is 110 °C. The experimental results show that water‐cooling packages are an effective means to realize high‐power white laser sources. [ABSTRACT FROM AUTHOR]

This paper presents an Inductive Power Transfer (IPT) system for Electric Vehicle (EV) charging with Power Class Interoperability (PCI) between the SAE WPT3 (10 kW) and WPT5 (50 kW) power classes using a multi-coil Bi-Polar Pad (BPP) Vehicle Assembly (VA) magnetic topology. The objective is to provide wireless PCI for electric taxis and fleet vehicles which may require WPT5 charging while on shift and WPT3 off shift charging. The design process of the WPT3/5 BPP VA magnetics is presented. Alternative methods of ferrite core layout and coil overlap to reduce form factor and cross-coupling are investigated. A dual active bridge topology using LCC-LCC tuning demonstrates effective dual-sided control, combining conduction angle, active bridge phase shift, and Selective Coil Energization (SCE) to provide system functionality essential to PCI. Active bridge phase shift is utilized to adjust the relative secondary to primary phase past 90° to enable Zero-Volt Switching (ZVS) in the active bridges when operating at either power class. Experiments demonstrate the proposed WPT3/5 BPP VA charging from an above ground WPT3 UGA, and flush ground mounted WPT5 GA, and show an efficiency increase of 3.6% and 0.7% respectively when the proposed control method is used. The performance of the proposed system is shown to be comparable to other IPT systems at either power class.

In this paper, we introduce a novel over-mode groove-guide (OMGG) traveling wave tube (TWT) design and simulation methodology. The OMGG configuration permits larger electron beam tunnels horizontal dimensions, alleviating the spatial constraints of the tunnel in conventional slow wave structures (SWS). The over-mode characteristic of the OMGG allows the propagation of the operating mode without compromising the essential beam-wave interaction required for efficient amplification. Particle-In-Cell (PIC) results indicate that the OMGG TWT significantly enhances output power in W-band TWT. This advancement offers a promising approach for developing high-power, efficient TWTs suitable for millimeter-wave (MMW) and terahertz (THz) technologies. [ABSTRACT FROM AUTHOR]

Zhi-Bo Gu, Lei Qiu, Hua Zhu, Ming Lu, Jian-Gang Chen Department of Urology, Affiliated Hospital 2 of Nantong University, Nantong, Jiangsu Province, 226200, People’s Republic of ChinaCorrespondence: Jian-Gang Chen, Department of Urology, Affiliated Hospital 2 of Nantong University, No. 666 Victory Road, Chongchuan District, Nantong, Jiangsu Province, 226200, People’s Republic of China, 226200, Tel +862115996558081, Email jiangang_chenC1@126.comObjective: To compare low- vs high-power HoLEP effects on coagulation in patients on antiplatelet (AP) therapy via thromboelastography (TEG).Methods: 210 patients was retrospectively analyzed and stratificated into three discrete groups, specifically: Group A (AP therapy, high-power HoLEP, n = 72); Group B (AP therapy, low-power HoLEP, n=73); Group C (no AP therapy, low-power HoLEP, n = 65). Baseline characteristics and coagulation profiles via TEG were compared. Univariate and multivariate analyses were conducted to identify independent risk factors associated with hematuria. Furthermore, parameters such as IPSS, Qmax, post-void residual volume V2 and PSA levels were recorded during 1year follow-up.Results: No differences in terms of baseline characteristics across all groups. Significant differences were observed in the duration of enucleation, morcellation, bladder irrigation, post-operative catheterization, length of hospital stay and the extent of hemoglobin reduction (F = 54.06, 8.54, 6.68, 9.24, 17.06, 5.97, p 0.05). Univariate and multivariate analyses revealed that prostate volume emerged as an independent risk factor for hematuria (OR 1.080, 95% CI: 1.007– 1.158, p = 0.031). Clinical outcomes including Qmax, IPSS, V2, and PSA demonstrated significant enhancement during 1 year follow-up.Conclusion: Compared to HP-HoLEP, LP-HoLEP effectively reduces surgical and subsequent processing times, decreases hospital stay duration, and diminishes hemoglobin decline, offering a viable option without discontinuing AP therapy.Keywords: anti-platelet therapy, BPH, high power, HoLEP, low power

In order to increase the productivity, new generation of selective laser melting (SLM) machines are evolving towards higher power lasers. In this paper, the microstructure evolution and mechanical properties of 24CrNiMoY alloy steel fabricated by high power selective laser melting (HP-SLM) have been reported. The results show that with the optimized laser power over 400 W, the powder layer thickness can be increased to 60 μm, and the theoretical productivity reaches 7.2 mm3/s, which is more than two times of the normal SLM technology. As the laser energy density increases, the structure of melt pool changes from a thermal conduction mode to a keyhole mode, and the microstructure mainly consists of martensite, bainite and pre-eutectic ferrite, and the phase composition of the specimen is α-Fe phase and a small amount of Fe3C,with fine grain size and irregular orientation. When the laser energy density is 68 J/mm3, the microhardness of the specimen is 410HV0.2, the tensile strength reaches 1121 MPa and the percentage elongation after fracture is 11.5%, which realizes a good match between strength and ductility. The fine tempered martensite and lower bainite in the microstructure is the key to excellent strength and ductility. This research is of guiding significance and serves as a technical reference for understanding the microstructure evolution and mechanical properties of HP-SLM 24CrNiMoY alloy steel.

The standard treatment procedures for managing renal calculi in the pediatric population are similar to those in adults. The application of flexible ureteroscopy has contributed to the increased popularity of retrograde intrarenal surgery (RIRS) as an alternative therapeutic modality that can be successfully applied in children. One of the most significant innovations of the last decade is the introduction of single-use flexible ureteroscopes (fURSs). In this case report, we present the case of a 2-year-old boy with multiple large calculi in his right kidney, which were successfully removed after a single session of RIRS using a 7.5 F single-use fURS and high-power laser settings. The total operative and lithotripsy times were estimated at 90 and 75 min, respectively. No complications were recorded. The hemoglobin loss was calculated at 0.3 mg/dL, while the creatinine level was decreased by 0.1 mg/dL. The urethral catheter was removed on the first postoperative day, and the patient was discharged. The management of multiple or large kidney stones is very challenging in the pediatric population under the age of three years. Convenient preoperative planning and the appropriate use of available equipment may lead to excellent outcomes accompanied by a reduced risk for complications.

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In order to improve the independent control ability of related products in the field of RF defrosting, a design scheme of high-power RF defrosting module composed of nationally produced transistor amplifier circuit is proposed based on the domestic self-developed lateral diffused metal oxide semiconductors (LDMOS) power chip. The core amplifier circuit part of this scheme adopts three-stage cascaded self-research power amplifiers, which are DS5089 of the pre-stage, DS6S0910P of the driver stage and DS300AN of the last stage, and the high power RF defrosting module is designed. The RF performance test, function test and reliability test are carried out on the module. The experimental results show that the module designed based on domestic transistor has good RF performance, saturated output power is more than 53 dBm, power conversion efficiency exceeds 60%, and it can quickly and effectively complete the food defrosting within a specific period of time. The research conclusions provide a reference for the design of domestic transistor amplifier circuits in the field of RF defrosting [ABSTRACT FROM AUTHOR]

The Spaceborne Global Lightning Location Network (SGLLN) serves the purpose of identifying transient lightning events occurring beneath the ionosphere, playing a significant role in detecting and warning of disaster weather events. To ensure the effective functioning of the wideband electromagnetic pulse detector, which is a crucial component of the SGLLN, it must be tested and verified with specific signals. However, the inherent randomness and unpredictability of lightning occurrences pose challenges to this requirement. Consequently, a high-power electromagnetic pulse radiation system with a 20 m aperture reflector is designed. This system is capable of emitting nanosecond electromagnetic pulse signals under pre-set spatial and temporal conditions, providing a controlled environment for assessing the detection capabilities of SGLLN. In the design phase, an exponentially TEM feed antenna has been designed firstly based on the principle of high-gain radiation. The feed antenna adopts a pulser-integrated design to mitigate insulation risks, and it is equipped with an asymmetric protective loading to reduce reflected energy by 85.7%. Moreover, an innovative assessment method for gain loss, based on the principle of Love's equivalence, is proposed to quantify the impact of feed antenna on the radiation field. During the experimental phase, a specialized E-field sensor is used in the far-field experiment at a distance of 400 m. The measurements indicate that at this distance, the signal has a peak field strength of 2.2 kV/m, a rise time of 1.9 ns, and a pulse half-width of 2.5 ns. Additionally, the beamwidth in the time domain is less than 10°. At an altitude of 500 km, the spaceborne detector records a signal with a peak field strength of approximately 10 mV/m. Particularly, this signal transformed into a nonlinear frequency-modulated signal in the microsecond range across its frequency spectrum, which is consistent with the law of radio wave propagation in the ionosphere. This study offers a stable and robust radiation source for verifying spaceborne detectors and establishes an empirical foundation for investigating the impact of the ionosphere on signal propagation characteristics. [ABSTRACT FROM AUTHOR]

A 220 GHz GaN‐based monolithic integrated frequency doubler with high continuous‐wave output power has been developed. The doubler achieves improved heat dissipation by establishing the terahertz (THz) monolithic integrated circuit topology with GaN Schottky barrier diodes integrated on a high thermal conductivity SiC substrate. It features six anodes to enhance the power‐handling capabilities. A refractory Schottky metal stack is adopted for better thermal stability. The doubler realizes satisfactory performance by introducing the suspended microstrip and an all‐in‐one output structure. For verification, a prototype of the proposed frequency doubler was fabricated and tested. Measured results show that the proposed doubler produces a continuous‐wave output power of 255 mW at 220 GHz with an efficiency of 14.6%, exhibiting excellent potential for powerful THz sources. [ABSTRACT FROM AUTHOR]

The development of new space missions and the growing interest in space exploration have created an urgent need to develop high-thrust propulsion systems capable of propelling spacecraft far beyond the Earth and the solar system for long periods. Electric propulsion can potentially enable space missions to reach speeds thousands of times greater than conventional high-thrust chemical rockets. However, high speed comes at the cost of low power-to-thrust efficiency when considering propulsion systems as a whole, including the power generation system, transmission lines, and thrusters, which prevents high thrust from being achieved with any conceivable power system, resulting in long acceleration times. In addition, modern electric propulsion systems rely on external power sources that suffer significant power transfer losses at the high power levels required for high thrust levels. In addition, modern electric propulsion systems suffer from a number of critical physical and engineering problems that affect thrust levels and longevity. In addition, modern electric propulsion systems do not follow the principles of generation and acceleration of plasma flow that can be observed in space and potentially borrowed for artificial applications. This paper discusses several promising electrodeless plasma thruster concepts for high-power, high-thrust electric propulsion systems based on a combined power source/power converter/thruster architecture. These concepts have the potential to overcome modern limitations of high-power electric propulsion systems and enable new outer space missions that would not be possible with conventional thrusters. [ABSTRACT FROM AUTHOR]

The GaN photoconductive semiconductor switches (PCSSs) with low leakage current and large on-state current are suitable for several applications, including fast switching and high-power electromagnetic pulse equipment. This paper demonstrates a high-power GaN lateral PCSS device. An output peak current of 142.2 A is reached with an input voltage of 10.28 kV when the GaN lateral PCSS is intrinsically triggered. In addition, the method of retaining the AlGaN/GaN heterostructure between electrodes on PCSSs is proposed, which results in increasing the output peak current of the PCSS. The damage mechanism of the PCSS caused by a high electric field and high excitation laser energy is analyzed. The obtained results show that the high heat generated by the large current leads to the decomposition of GaN, and thus, the Ga forms a metal conductive path, resulting in the failure of the device. [ABSTRACT FROM AUTHOR]

This paper introduces a semiconductor optical amplifier (SOA) with high power and narrow linewidth broadening achieved through active region mode control. By integrating mode control with broad-spectrum epitaxial material design, the device achieves high gain, high power, and wide band output. At a wavelength of 1550 nm and an ambient temperature of 20 °C, the output power reaches 757 mW when the input power is 25 mW, and the gain is 21.92 dB when the input power is 4 mW. The 3 dB gain bandwidth is 88 nm, and the linewidth expansion of the input laser after amplification through the SOA is only 1.031 times. The device strikes a balance between high gain and high power, offering a new amplifier option for long-range light detection and ranging (LiDAR). [ABSTRACT FROM AUTHOR]

A novel 10-Watt-Level high-power microwave rectifier with an inverse Class-F harmonic network for microwave power transmission (MPT) is presented in this paper. The high-power microwave rectifier circuit comprises four sub-rectifier circuits, a 1 × 4 power divider, and a parallel-series dc synthesis network. The simple inverse Class-F harmonic control network serves dual roles: harmonic control and impedance matching. The 1 × 4 power divider increases the RF input power fourfold, reaching 40 dBm (10 W). The parallel-series dc synthesis network enhances the resistance to load variation. The high-power rectifier circuit is simulated, fabricated, and measured. The measurement results demonstrate that the rectifier circuit can reach a maximum RF input power of 10 W at 2.45 GHz, with a maximum rectifier efficiency of 61.1% and an output dc voltage of 23.9 V, which has a large application potential in MPT. [ABSTRACT FROM AUTHOR]

Dual‐ion batteries (DIBs) represent a promising alternative for lithium ion batteries (LIBs) for various niche applications. DIBs with polymer‐based active materials, here poly(2,2,6,6‐tetramethylpiperidinyl‐N‐oxyl methacrylate) (PTMA), are of particular interest for high power applications, though they require appropriate electrolyte formulations. As the anion mobility plays a crucial role in transport kinetics, Li salts are varied using the well‐dissociating solvent γ‐butyrolactone (GBL). Lithium difluoro(oxalate)borate (LiDFOB) and lithium bis(oxalate)borate (LiBOB) improve cycle life in PTMA||Li metal cells compared to other Li salts and a LiPF6‐ and carbonate‐based reference electrolyte, even at specific currents of 1.0 A g−1 (≈10C), whereas LiDFOB reveals a superior rate performance, i. e. ≈90 % capacity even at 5.0 A g−1 (≈50C). This is attributed to faster charge‐transfer/mass transport, enhanced pseudo‐capacitive contributions during the de‐/insertion of the anions into the PTMA electrode and to lower overpotentials at the Li metal electrode. [ABSTRACT FROM AUTHOR]

Developing suitable cathodes with high capacity and high power is challenging for K‐ion batteries. Herein, electrochemical K‐ion storage properties of the layered‐type K0.4V2O5 (KVO) cathode by incorporating divalent strontium ions (Sr2+) into its crystal structure are enhanced. Divalent strontium ions (1.18 Å) are preferentially incorporated into the octahedrally coordinated K (1.38 Å) layers due to the similar ionic size compared to V4+ (0.58 Å). The introduction of 3 mmol of Sr ions in the KVO crystal improves electrical conductivity and reduces K‐ion diffusion energy barriers. In addition, the strong Sr2+ and O2− interaction acts as a structural pillar, suppressing irreversible phase transition during charge–discharge process. Multi‐physics simulations clearly confirm that the K0.34Sr0.03V2O5 (KS3VO) cathode exhibits a more uniform K‐ion distribution and enhanced reactions of K‐ions compared to the KVO cathode at various depths of discharge. As a result, the KS3VO cathode demonstrates improved reversible capacity, cycling stability, and power capability over the KVO cathode in a K‐ion cell. Synchrotron X‐ray analysis reveals how Sr substitution enhances the electrochemical K‐ion storage properties of the KS3VO cathode. In addition, the KS3VO cathode exhibits superior thermal stability and cycling stability in a full cell coupled with a hard carbon anode compared to the KVO cathode. [ABSTRACT FROM AUTHOR]

This paper presents the design of a Gallium Nitride (GaN) transistor-based ultra-wideband (UWB) high-efficiency power amplifier (PA) with 25W (44 dBm) output power operating in the 2-6 GHz frequency band. The design of the matching circuits is based on a simplified systematic approach utilizing the target impedance trajectory. The Macom CGHV1F025S model GaN transistor and Rogers RT5870 model substrate are used in the design. The experimental results show that performance of the implemented PA offers 9.8 dB power gain, 43.8 dBm output power, and power-added efficiency (PAE) between 41% and 57% in the 2-6 GHz band. [ABSTRACT FROM AUTHOR]

The standard treatment procedures for managing renal calculi in the pediatric population are similar to those in adults. The application of flexible ureteroscopy has contributed to the increased popularity of retrograde intrarenal surgery (RIRS) as an alternative therapeutic modality that can be successfully applied in children. One of the most significant innovations of the last decade is the introduction of single-use flexible ureteroscopes (fURSs). In this case report, we present the case of a 2-year-old boy with multiple large calculi in his right kidney, which were successfully removed after a single session of RIRS using a 7.5 F single-use fURS and high-power laser settings. The total operative and lithotripsy times were estimated at 90 and 75 min, respectively. No complications were recorded. The hemoglobin loss was calculated at 0.3 mg/dL, while the creatinine level was decreased by 0.1 mg/dL. The urethral catheter was removed on the first postoperative day, and the patient was discharged. The management of multiple or large kidney stones is very challenging in the pediatric population under the age of three years. Convenient preoperative planning and the appropriate use of available equipment may lead to excellent outcomes accompanied by a reduced risk for complications. [ABSTRACT FROM AUTHOR]

A high-throughput laser micro-machining system has been developed using a programmable multi-spot modulated line beam capable of >30x throughput enhancement over a single-spot system. While commercially available lasers have been rapidly growing in output energy and power, single-spot scanning systems cannot take full advantage of these advancements. This system provides high throughput, high resolution micro-processing on a variety of surfaces (stainless steel, aluminum, and polymer). This high productivity system is enabled by a high-power MEMS spatial light modulator called the Planar Light Valve (PLVTM). The PLV is a 1088-pixel device in a linear configuration capable of 10-bit, 100 kHz amplitude modulation. The PLV supports pulse energies of ~1 mJ (1064 nm, 10 ps) and has been used at pulse widths down to 300 femtoseconds. The system can resolve features as small as 10 µm with an edge placement resolution of 2.5 µm. Large area processing is done by scanning and stitching this line beam across the media using X-Y stages and a unique relay galvo scanner has been incorporated into the system to allow for faster scanning over a 15 x 15 mm area. [ABSTRACT FROM AUTHOR]

Lithium‐ion insertion/deinsertion in anode at slow rates limits the power performance of energy storage devices. Here, a new pseudocapacitive electrode with high reversible capacity during cycling has been proposed for a lithium‐ion capacitor. The lithium‐fluoride garnet, namely Na3Fe2Li3F12, is obtained via precipitation from an aqueous solution at room temperature using abundant materials and exhibits a high discharge capacity of 746 mAh g−1. After the first charging cycle, the energy is stored via fast pseudocapacitive faradaic reactions which are facilitated by the nanocrystalline transport pathways with no structural modification to the electrode. The high stability window of F‐garnet allows extracting cell voltages of 2.2–3.2 V in a lithium‐ion capacitor where it is coupled with a porous carbon‐based positive electrode, with a high energy efficiency of 93 % maintained for 10000 charge/discharge cycles. This study opens a new research direction concerning pseudocapacitive anode materials for enhancing power performance and even replacing the traditional battery‐like anode materials. [ABSTRACT FROM AUTHOR]

In this study, a kilowatt-level high-efficiency narrow-linewidth all-fiber Tm3+-doped continuous-wave laser operating at 1.95 μm is demonstrated. Benefitting from an advanced boost design of a two-stage main amplifier, it not only effectively manages heat dissipation resulting from the high pump-induced quantum defect but also realizes the controlled extraction of optical gain and improves the optical conversion efficiency. Finally, this laser system has realized an output power of 1018 W, a linewidth of 3.8 GHz, and a slope efficiency of 60.0% simultaneously. Moreover, a high optical signal-to-noise ratio of over 45 dB and excellent beam quality of M2 factors 1.19 are obtained. To the best of our knowledge, this represents the narrowest linewidth and highest slope efficiency achieved in a kilowatt-level Tm³⁺-doped fiber laser. Such a high-performance laser is ideally suited for mid-infrared generation and remote sensing applications. [ABSTRACT FROM AUTHOR]

Microwave-assisted mechanical excavation has great application prospects in mines and tunnels, but there are few field experiments on microwave-assisted rock breaking. This paper takes the Sishanling iron mine as the research object and adopts the self-developed high-power microwave-induced fracturing test system for hard rock to conduct field experiments of microwave-induced fracturing of iron ore. The heating and reflection evolution characteristics of ore under different microwave parameters (antenna type, power, and working distance) were studied, and the optimal microwave parameters were obtained. Subsequently, the ore was irradiated with the optimal microwave parameters, and the cracking effect of the ore under the action of the high-power open microwave was analyzed. The results show that the reflection coefficient (standing wave ratio) can be rapidly (

A split-stepped gate field plate design has been incorporated on a gallium oxide (Ga2O3) metal-oxide semiconductor field-effect transistor (MOSFET). The aim of the present work is to unfold the potential of Ga2O3 MOSFET by enhancing its breakdown limits and also to overcome the challenge of simultaneous improvement in power as well as radio frequency (RF) metrics. An extensive simulation study focusing on analog and RF metrics has been carried out using technology computer-aided design simulations of the proposed device in a calibrated environment, and a comparative analysis of split stepped gate field plate design, shorted stepped gate field plate design, and conventional Ga2O3 MOSFET design has also been performed. The results highlight the superiority of the proposed device, and a substantial enhancement in breakdown voltage (i.e., 106.36% relative increase) and power figure-of-merit (i.e., 282.70% relative increase) has been demonstrated. [ABSTRACT FROM AUTHOR]

We report a 2.8 μm all-fiber high-power and high-energy gain-switched Er3+:ZBLAN laser based on dielectric fiber mirror and fiber-tip protection. The fiber pigtail mirror, specifically designed for dichroic operation (i.e., anti-reflection at 976 nm pump wavelength and high-reflection around 2.8 μm laser wavelength), shows high damage density of >10 MW/cm2. An anti-reflection protective film is coated on the input tip of Er3+:ZBLAN fiber and an AlF3 endcap is spliced to the output tip of Er3+:ZBLAN fiber for mitigating the fiber-tip photodegradation and high-power catastrophic failure at 2.8 μm. The compact all-fiber cavity is formed by efficiently connecting the Er3+:ZBLAN fiber with dielectric fiber mirror using the standard FC/PC fiber adaptor. When the 976 nm pump operates in pulsed regime, the all-fiber mid-infrared gain-switched laser can be attained with two states of single-pulse and pulse-burst output. The extracted maximum pulse energy is 4.8 μJ in the single-pulse state, and the shortest pulse width is 426 ns. The pulse-burst mode can generate a maximum average power of 5.291 W and burst energy of 264.55 μJ. This work may offer a promising way to realize the low-cost, all-fiber, high-power and high-energy gain-switched laser at MIR wavelengths. [ABSTRACT FROM AUTHOR]

We experimentally studied the transverse mode instability (TMI) threshold of a linearly polarized single-frequency fiber laser amplifier constructed with tapered ytterbium-doped fiber (TYDF) under different bending diameters. The TMI threshold increased from 333 W to 451 W by reducing the bending diameter from 16 cm to 12 cm, which was accompanied by the deterioration of the beam quality from 1.47 to 1.67. The anomalous characteristics between the TMI threshold, bending diameter, and beam quality are mainly attributed to the decreased bending loss of higher-order mode (HOM) content as a result of the increased system heat loads caused by a tight bending-induced loss of amplification efficiency. It is believed that the presented results will provide useful guidelines for the design of high-power single-frequency fiber amplifiers. [ABSTRACT FROM AUTHOR]

In this paper, a GaN high-electron-mobility transistor (HEMT) compact high-power wide-band power amplifier with an operation frequency from 0.8 GHz to 2 GHz is proposed. In order to realize a compact design, an internally matched method is employed. A wide-band matching strategy with an LC network and a multi-stage wide-band power combiner/divider is introduced in this design to achieve a wide bandwidth. A power combination structure is applied to have high output power. Wire-spiral inductance and film capacitors are employed to construct the compact matching network. The equivalent inductance of the bonding wire is also involved in the matching network. Experimental results show that the PAE (power-added efficiency) during the whole operation's bandwidth (0.8 GHz to 2.0 GHz) is from 40% to 57%. The output power can reach from 48.3 dBm to 49.8 dBm with a circuit size of 30.8 × 27.4 mm 2 . [ABSTRACT FROM AUTHOR]

The management of renal stones, particularly those less than 2 cm in diameter, has changed with the development of endourological techniques, among which flexible ureteroscopy (FURS) using laser for lithotripsy has become a cornerstone. This study aims to compare the effectiveness of high pulse energy versus low pulse energy laser settings in renal stone dusting by Holmium YAG laser. This prospective randomized study was conducted between September 2021 and November 2023 to compare the efficacy and safety of high energy versus low-energy pulse settings using a Holmium: YAG laser dusting of renal stones less than 2 cm in diameter. A total of 174 adult patients were included, divided equally into high- and low-pulse energy groups, based on the energy settings of the laser high energy (ranged from 1.2–2.5 Joules and frequency of 8 hz) and low energy (less than 0.5 Joules and frequency ≥ 15 hz) using the dusting ‎technique with non-touch non-stop approach. The study sought to evaluate the impact of these settings on stone fragmentation efficiency, operative time, laser energy consumption, and postoperative outcomes, including stone-free rates and complications. The study involved 174 patients who underwent renal stone lithotripsy and showed that using high pulse energy laser dusting settings significantly reduced operative times and more rapid dusting compared to low pulse energy settings, without affecting the stone-free rate. The study observed no significant differences in stone size or location between both groups. Minor postoperative complications were similar between both groups, indicating high pulse energy settings for lithotripsy dusting. The efficacy of high pulse energy dusting in enhancing stone removal during surgery, potentially reducing operative time. Further validation through larger-scale studies is needed to solidify these findings. This technique presents a promising solution, particularly in regions with limited resources where acquiring expensive laser equipment is challenging. [ABSTRACT FROM AUTHOR]

The high‐power characteristic of the coaxial to waveguide transition plays an important role in modern communication and radar systems. In this letter, a novel design of a high‐power transition from a 50 Ω coaxial line with an N‐type connector to a WR‐90 rectangular waveguide. The power handling capability (PHC) of the proposed structure is significantly enhanced by a cone‐shaped excitation probe with a bold end, a transitional cavity, and a mode conversion cavity with a curved shorted back wall. The simulated results reveal that the transition possesses high PHC of 257 kW at 8.5 GHz, which is the upper limit of the power tolerance for the N‐type connector. The measured results show that the return loss and insertion loss are better than 15 and 0.15 dB, respectively, in the range of 7.96–9.16 GHz. In addition, experimental validation confirms the normal operation of the structure under a 250 kW power level test, demonstrating the applicability of the proposed transition in high‐power microwave systems. [ABSTRACT FROM AUTHOR]

Since there is insufficient evidence to determine the best treatment of transurethral laser lithotripsy (TLL) in ureteral stones, this study compared the effectiveness and safety of TLL using high-power (HP) (100 W) and low-power (LP) (20 W) laser settings. All patients with maximally sized ureteral stones who were planned for transurethral holmium laser lithotripsy were enrolled in this open study. One of the two laser setting groups–LP or HP–was allocated to each alternate patient. Using IBM SPSS Statistics 24, the treatment groups were compared for operating time, intraoperative and postoperative problems (up to 1 year), and rates of stone-free recovery. Welch tests were employed to compare continuous data, whereas Fisher’s exact or Chi-square tests were used to assess categorical variables. At P < 0.05, statistical significance was established. A total of 207 individuals were included and preoperative data were comparable between the two groups. The HP group had a considerably greater ablation rate and a significantly shorter procedure duration (42.61 ± 11.74 min) than the LP group (78.56 ± 25.91 min) (P = 0.025). The Overactive Bladder Symptom Score and International Prostate Symptom Score were considerably higher in the HP group than in the LP group. Treatment effectiveness was considerably impacted by the location of the ureteral stone, according to univariate and multivariate logistic regression models. A HP laser setting of up to 100 W greatly shortens the duration of the process for treating ureteral stones without raising the risk of problems.

Since there is insufficient evidence to determine the best treatment of transurethral laser lithotripsy (TLL) in ureteral stones, this study compared the effectiveness and safety of TLL using high-power (HP) (100 W) and low-power (LP) (20 W) laser settings. All patients with maximally sized ureteral stones who were planned for transurethral holmium laser lithotripsy were enrolled in this open study. One of the two laser setting groups–LP or HP–was allocated to each alternate patient. Using IBM SPSS Statistics 24, the treatment groups were compared for operating time, intraoperative and postoperative problems (up to 1 year), and rates of stone-free recovery. Welch tests were employed to compare continuous data, whereas Fisher's exact or Chi-square tests were used to assess categorical variables. At P < 0.05, statistical significance was established. A total of 207 individuals were included and preoperative data were comparable between the two groups. The HP group had a considerably greater ablation rate and a significantly shorter procedure duration (42.61 ± 11.74 min) than the LP group (78.56 ± 25.91 min) (P = 0.025). The Overactive Bladder Symptom Score and International Prostate Symptom Score were considerably higher in the HP group than in the LP group. Treatment effectiveness was considerably impacted by the location of the ureteral stone, according to univariate and multivariate logistic regression models. A HP laser setting of up to 100 W greatly shortens the duration of the process for treating ureteral stones without raising the risk of problems. [ABSTRACT FROM AUTHOR]

Small molecule quinone compounds are attractive cathode materials for rechargeable aqueous zinc‐organic batteries (AZOBs) because of their structural diversity and low‐cost merits. Among them, nonpolar quinones are dominant given the relatively low solubilities in aqueous electrolytes. However, their poor electronic conductivity and accumulated Coulombic repulsion lead to underutilized active sites and sluggish redox kinetics. Here, polar 2,6‐dimethoxy‐1,4‐benzoquinone (m‐DMBQ) works as an advanced AZOB cathode with unexpectedly superior performance over the nonpolar isomer of 2,5‐dimethoxy‐1,4‐benzoquinone (p‐DMBQ). The asymmetric charge distribution of active centers in the p−π conjugated backbone of m‐DMBQ induces reduced bandgap with improved electronic conductivity and redox activity, thus achieving a high specific capacity of 312 mAh g−1 approaching the theoretical limit. Additionally, the lowest unoccupied molecular orbital energy level is lowered for an increased average discharge voltage of 0.88 V. Characterizations and computational studies revealed boosted competitiveness of H+ relative to Zn2+ for significantly enhanced charge transfer kinetics and reversibility. As a result, the as‐fabricated AZOB achieves a high energy density of 275 Wh kg−1 based on m‐DMBQ along with high‐rate capability and long‐term cycling stability. This work provides a new molecular engineering strategy through regulating charge distribution symmetry for boosting charge storage in organic cathodes. [ABSTRACT FROM AUTHOR]