1W Output Power Research Articles

A 2–10-GHz Reconfigurable GaN Power Amplifier With Average Power-Added Efficiency of 30% and Output Power of 2 W

In this brief, a 2–10 GHz reconfigurable power amplifier (PA) with power-added efficiency (PAE) of 30% and output power of 2W is proposed using commercial <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.25~\mathbf {\mu }\text{m}$ </tex-math></inline-formula> GaN technology. It consists of two-stage amplifier transistors with reconfigurable input, inter-stage and output matching networks. By utilizing the reconfigurable matching networks, the proposed PA circuit divides the frequency band of 2–10 GHz into three continuous sub-frequency bands, and achieves high power added efficiency and gain in each sub-frequency band. As a result, the proposed PA can simultaneously maintain high efficiency and high gain and cover multioctave bandwidth. Moreover, in order to further improve the efficiency, harmonic suppression is used in low-band with open circuit impedance at third harmonic. With these techniques, the proposed PA covers frequency band of 2–10 GHz, delivers an average PAE of 38% at 2–5 GHz, 31% at 5–7 GHz, and 31.5% at 7–10 GHz. Good agreement between simulation and measurement is obtained.

Comparative Study of Oral Soft Tissue Operations Using a Laser vs. a Scalpel

Background: The oral cavity, which stretches from the lips to the oropharynx, is the initial portion of the digestive system. Materials and Method: Twenty-eight separate oral soft tissue surgeries were performed, fourteen with a 940 nm Diode laser with an output power of 1W and the other fourteen with a scalpel. Results: Although there was no difference in healing between the two groups, patients who were operated on with a laser felt more comfortable than those who were operated on with a conventional manner.

MODELLING OF CAPACITIVE POWER TRANSFER SYSTEM BASED ON CLASS-E LCCL TOPOLOGY

Nowadays, capacitive power transfer (CPT) is becoming increasingly popular technology in the wireless charging field due to its better mobility and higher durability. This paper proposed a CPT system by using Class-E inverter. This topology is selected due to its ability to achieve 100% efficiency theoretically. L-match impedance matching circuits are applied at both transmitter and receiver part to allow the load impedance to match with the source impedance to maximize the power transfer. The proposed CPT system is designed and simulated by using Simulink in MATLAB software. Its output performances are analyzed. Besides, the designed CPT system is used to investigate the factors that affect its output performance by varying the load, duty cycle and gap distance between coupling plates. From this work, the proposed CPT system produced up to 97.35% efficiency and output power of 10W.

The design of an efficient class E-LCCL capacitive power transfer system through frequency tuning method

In this work, the optimum zero voltage switching (ZVS) of Class E-LCCL capacitive power transfer (CPT) was determined via frequency tuning method. Through this an efficient system can be guanranteed although there is a change in the capacitive plates distance. This study used a Class-E LCCL inverter, as it can operate at a high alternate current frequency, besides producing low switching losses and minimal power losses. Specifically, this study conducted simulations and experiments to analyse the performance of an LCCL CPT System at 1 MHz operating frequency and 24 V DC supply voltage. Using an air gap distance of 0.1 cm, the designed CPT system prototype successfully achieved an output power of 10W and an efficiency of 95.45%. This study also found that by tuning the resonant frequency of the Class E-LCCL system, the optimum ZVS can be obtained although capacitive plate distance was varied from 1-3 cm via experimental. The results of this study could benefit medical implant and portable device development, consumer electronics, and environments that involve electrical hazards.

Diode optical amplifier with phase control of the output wave for high-power laser systems with coherent beam combining

A three-section optical diode amplifier is simulated, whose sections have different amplitude-phase coupling coefficients R (linewidth enhancement factors). We show that it is possible to change the output wave phase for a constant output power due to only a difference in the value of this coefficient. In a single-mode amplifier, the first section has a horizontal waveguide formed by the gain (gainguided), and the other two sections are formed by change of the refractive index (index-guided). The values of the current in the first two sections are found, at which the phase changes by more than 2π at a constant output power of 2W. Such amplifiers can be integrated into single-crystal bars, which makes them adaptive for use in kilowatt laser systems with a coherent combining of beams.

12-W continuous-wave green output from a 200-μm fiber-coupled diode laser based on TO-Can packaged emitters.

A 12-W green laser diode module with fiber-coupled output is developed. The high-power fiber-coupled output of a green diode laser is realized by using the technologies of beam collimation, spatial beam combining, beam shaping, and fiber coupling based on TO-Can packaged emitters. According to the optical fiber parameters, the detailed beam combination method is described and the maximum quantity of a single emitter in beam combination is calculated theoretically. In the experiment, as many as 16 green laser diode emitters with output power of 1W each were combined and coupled into a fiber with core diameter of 200μm and a numerical aperture of 0.22. A total of 12.2W continuous-wave output at the wavelength of 520nm was achieved with a coupling efficiency of 86.5% and an electro-optical efficiency of 10.6%.

Frequency- and intensity-noise suppression in Yb3+-doped single-frequency fiber laser by a passive optical-feedback loop.

The frequency and intensity noise of an Yb3+-doped single-frequency distributed Bragg reflector (DBR) fiber laser are effectively reduced by a simple, passive optical-feedback loop (POFL), which consists of only two optical couplers. The feedback loop, which has resonance with the high reflective grating of the DBR laser and relative long optical path compared to the DBR cavity, results in narrower linewidth and lower relative intensity noise (RIN) in the feedback signal. The RIN of relaxation oscillation is reduced by 20dB from -99.9dB/Hz @ 993 kHz to -119.4dB/Hz @ 192 kHz, and the frequency noise was suppressed at frequencies higher than 1 kHz, with a maximum reduction of about 30 dB from 10 kHz to 100 kHz, which results in a spectral linewidth compression from 3.96 kHz to 540 Hz. Even after one fiber amplification stage, the noise did not increase significantly, and a spectral linewidth well below 1 kHz were also achieved at output power of 10W.

~1 µm laser output based on heterogeneous fiber with Yb3+-doped fluorophosphate core and phosphate cladding

A broad Stark splitting of Yb3+-doped fluorophosphate (FP) core glass and phosphate cladding glass with outstanding thermal and mechanical performance were prepared in this work. Yb3+-doped FP core and phosphate cladding heterogeneous fiber with hexagonal-shape inner cladding was fabricated by the stack-and-draw method. A maximum output power of 2W was obtained with slope efficiency of 25.6% from a 35cm fiber. The laser spectrum had a full width at half maximum (FWHM) of 1.5nm with the central wavelength at 1013nm. Therefore, FP glass fiber might be a good alternative for gain medium in short-linear-cavity single-frequency fiber laser.

Evaluation of temperature change during antimicrobial photodynamic therapy with two different photosensitizers in dental caries

IntroductionMany attempts have been made in elimination of bacteria in infected and demineralized dentin to not only provide efficient bactericidal potential, but to have minimal damage for tooth structure. The aim of this study was to assess the temperature change during aPDT with ICG and TBO compared with conventional Diode laser irradiation. Materials and methods48 premolar teeth which were selected for this study. A class I cavity was drilled in each teeth, with dimensions of 2mm width, 4mm length and depth of 2.5–3.5mm, providing a dentinal wall of approximately 0.5mm for pulp chamber. Then teeth were randomly allocated in 4 experimental groups (n=12); Group 1: TBO+LED, Group 2: ICG+Diode Laser, Group 3: Diode laser with output power of 0.5W, Group 4: Diode laser with output power of 1W. Thermocouple device was held by experimenter hand and the sensor was in pulp chamber of the teeth. Heat generated during irradiation was reported on LCD screen by NUX Plus software. Repeated measure ANOVA was used in order to compare the temperature before and after laser application. Tukey HSD was used to compare the results between groups. ResultsTemperature was risen for about 0.54±0.05°C for group 1, 1.67±0.14°C for group 2, 4.21±0.83°C for group 3, and 4. 50±0.32°C for group 4. The difference between group 1 & 2, 1 & 3 and 1 & 4 was significant (p<0.0001). ConclusionAccording to results of this study, Diode (with or without photosensitizer- 0.5 and 1W) can be safely used as alternative approach for disinfection after caries removal in thermal point of view.

Mode-locked femtosecond all-normal all-PM Yb-doped fiber laser at 1060 nm

We report an all-normal-dispersion, all-fibre, all-PM, laser operating at a central wavelength of 1060nm. The laser is mode-locked using a nonlinear amplifying loop mirror and generates linearly polarised pulses that can be compressed to 360fs. The laser is based on our earlier scheme operating at 1030nm [1] and we discuss the similarities and differences between the two configurations. We also present amplification up to an output power of 1W using a commercially built amplifier and show through numerical methods that this pulse may be recompressible to 1.65ps.

Effect of electromagnetic fields on highly diluted remedies measured by ultraviolet spectroscopy

Purpose: In homeopathy or anthroposophically extended medicine high dilutions are used. They showed significant differences in ultraviolet light (UV) transmission between controls and different dilution levels. Exposing such dilutions to physical factors such as UV light or elevated temperature (37�C) yielded significantly different UV transmissions values compared to unexposed dilutions. The aim was to test whether electromagnetic fields (EMF) of a mobile phone affect the UV absorbance of dilutions of Atropa belladonna (Ab) and quartz. Methods: Commercially available dilutions of Ab 4x, 6x, 12x, 15x, 30x and of quartz 6x, 12x, 15x, 30x were investigated. On 5 days, 4 samples of each dilution were exposed to the EMF by a mobile phone at 900MHz (GSM) with an output power of 2W for 3 h. Control samples were kept in a separate room. UV-absorbance of the samples in the range from 190 to 340 nm was measured in randomized order. The average absorbance from 200 to 340 nm and from 200 to 240 nm was compared between exposed and unexposed samples by a dependent t-test. Results: Between unexposed and exposed dilutions of Ab and quartz no significant differences were detected, except for quartz 12x over the range from 200 to 340 nm. Conclusion: Exposure of high dilutions of Ab and quartz to GSM EMF of a mobile phone did not alter UV absorbance of these dilutions.

Effect of Electromagnetic Fields on Highly Diluted Remedies Measured by Ultraviolet Spectroscopy

Purpose: In homeopathy or anthroposophically extended medicine high dilutions are used. They showed significant differences in ultraviolet light (UV) transmission between controls and different dilution levels. Exposing such dilutions to physical factors such as UV light or elevated temperature (37�C) yielded significantly different UV transmissions values compared to unexposed dilutions. The aim was to test whether electromagnetic fields (EMF) of a mobile phone affect the UV absorbance of dilutions of Atropa belladonna (Ab) and quartz. Methods: Commercially available dilutions of Ab 4x, 6x, 12x, 15x, 30x and of quartz 6x, 12x, 15x, 30x were investigated. On 5 days, 4 samples of each dilution were exposed to the EMF by a mobile phone at 900MHz (GSM) with an output power of 2W for 3 h. Control samples were kept in a separate room. UV-absorbance of the samples in the range from 190 to 340 nm was measured in randomized order. The average absorbance from 200 to 340 nm and from 200 to 240 nm was compared between exposed and unexposed samples by a dependent t-test. Results: Between unexposed and exposed dilutions of Ab and quartz no significant differences were detected, except for quartz 12x over the range from 200 to 340 nm. Conclusion: Exposure of high dilutions of Ab and quartz to GSM EMF of a mobile phone did not alter UV absorbance of these dilutions.

Microwave selective thermal development of latent fingerprints on porous surfaces: potentialities of the method and preliminary experimental results.

The thermal development of latent fingerprints on paper surfaces is a simple, safe, and chemicals-free method, based on the faster heating of the substrate underlying the print residue. Microwave heating is proposed for the first time for the development of latent fingerprints on cellulose-based substrate, in order to add to the thermal development mechanism the further characteristic of being able to heat the fingerprint residues to a different extent with respect to the substrate, due to the intrinsic difference in their dielectric properties. Numerical simulation was performed to confirm and highlight the selectivity of microwaves, and preliminary experimental results point out the great potentialities of this technique, which allowed developing both latent sebaceous-rich and latent eccrine-rich fingerprints on different porous surfaces, in less than 30sec time with an applied output power of 500W. Microwaves demonstrated more effectiveness in the development of eccrine-rich residues, aged up to 12weeks.

Watt-class green-emitting laser modules using direct second harmonic generation of diode laser radiation

Large-area high-resolution displays, using a flying-spot to create the picture, require light sources in the red, green and blue wavelength range with a high optical output power and nearly diffraction limited beam. In this paper we present experimental results of high-brightness distributed Bragg reflector tapered diode lasers at 106x nm that can be used for single-pass second harmonic generation into the green. Based on these lasers we developed compact (2.5 cm3) green laser modules with an output power of 1W at 53x nm and an electro-optical conversion efficiency of about 5%. The output power stability is better than 2% and the wavelength stability is ±10 pm. The excellent beam quality Mδ2 < 2 of the green light allows operation in flying spot application systems. Furthermore, we estimate that our concept allows power scaling up to 2W by using nonlinear planar waveguide crystals and into the multi-watt level by spectral beam combining.

송신출력 증강에 따른 내륙 DGPS 기준국의 서비스 영역 분석

Korean NDGPS, which consists of the ocean-based reference station of 11 site and the land-based reference station of 6 sites, are operating. The land-based reference stations provide the output power of 500W, the service shadow regions are occurred due to mountains and nation topography. In this paper, the service coverages of land-based reference stations are analyzed in the viewpoint of output power enhancements of land-based reference stations within 1KW. Also, we suggest virtual land DGPS reference stations 2 sites to resolve the service shadow regions.

국내 DGPS 내륙 기준국의 출력 증강에 따른 서비스 영역 분석

우리나라는 GPS 보정시스템인 DGPS 위성항법보정시스템이 해안용 11곳과 내륙용 6곳의 기준국이 설치 되어 운용되고 있다. 내륙 기준국은 위성항법 보정신호를 500W 출력으로 서비스하고 있으나, 산간 지역 등 국내 지역에 따라 음영지역이 발생한다. 본 논문에서는 내륙 기준국의 출력을 1kW 이내에서 증강할 경우, 내륙 기준국별 서비스 영역을 해석하고, 6곳의 내륙 기준국과 11곳의 해안 기준국과의 이중 서비스 영역을 고려하여 국내 내륙지역의 DGPS 서비스 음영지역을 분석한다. DGPS 전파 모델로는 중파 대역 전파 모델을 사용하고, 내륙 지역의 도전율은 보정된 지표 도전율을 적용하여 출력에 따른 서비스 영역을 해석한다. The DGPS systems that is a GPS augmentation system were installed for ocean- and land-service. The ocean-based reference station of 11 site and the land-based reference station of 6 sites are operating for ocean- and land-service. Although the land-based reference stations provide the output power of 500W, the service shadow regions are occurred due to mountain lands and building area. In this paper, the service coverages for land-based reference stations are analyzed in conditions of output power enhancements of reference station. The service shadow areas are deduced from service coverages of land-based reference stations and ocean-based reference stations. The medium frequency-band wave propagation models are considered as DGPS wave propagation model. The service coverages are analyzed by considering the compensated ground surface-conductivity.

Linear Quadratic Gaussian Optimal Controlled Two-Stage Inverter for a High-Frequency AC Distribution Power System

The linear quadratic Gaussian Optimal control of a two-stage HFAC inverter system has been investigated in this paper. The uncertainty model of the high frequency resonant inverter is developed and analyzed with the input line and load variations taken into design considerations. The proposed control scheme has the advantages of fast response for both input line and load perturbations. It also ensures a wide range of system stability and guarantees robustness of the power converter. Both simulations and experimental results are provided to verify with the theoretical analysis through an experimental prototype with an output power of 500-W operating at 10 KHz and an output voltage of 24 V (peak value).

Effect of Pulse Energy, Frequency and Length on Holmium:Yttrium-Aluminum-Garnet Laser Fragmentation Efficiency in Non-Floating Artificial Urinary Calculi

Holmium:yttrium-aluminum-garnet (Ho:YAG) laser lithotripsy is the standard lithotrite in ureteroscopy. We investigated the influence of pulse frequency, energy and length on the fragmentation efficiency of Ho:YAG laser lithotripsy in non-floating artificial stones in vitro. Stone fragmentation efficiency of three different Ho:YAG laser devices were evaluated in vitro at different pulse energy (1.0 and 2.0 J) and frequency settings (5 and 10 Hz), resulting in a standardized output power of 10W, respectively. Where possible, pulse length was modified (350 vs 700 microsec). Each setting was performed with a 273 microm and a 365 microm fiber. Lithotripsy was conducted using non-repulsive stones consisting of soft stone (plaster of Paris) and hard stone composition (Fujirock type 4). Our results showed an increased stone disintegration efficiency at higher pulse energy (2.0 J/5 Hz vs 1.0 J/10 Hz) independently of two fiber diameters and stone types applied in this study (P < 0.05 in 18 of 20 groups). Similarly, reduction of the pulse length from 700 to 350 microsec resulted in a higher stone disintegration (P < 0.05 in 13 of 16 groups). This effect was most prominent when applied to soft stones. Higher fiber diameter was not constantly associated with an increase in stone disintegration. We demonstrate that an increase of pulse energy and a reduction of pulse length at a standardized output power of 10W can improve Ho:YAG laser fragmentation efficiency in vitro in nonfloating stones. These results may potentially affect clinical practice of Ho:YAG laser lithotripsy in impacted or large stones, when retropulsion is excluded.

1277 IN VITRO EFFICACY OF HOLMIUM:YAG LASER LITHOTRIPSY IN NON FLOATING STONES. - EFFECT OF PULSE FREQUENCY, ENERGY AND LENGTH -

You have accessJournal of UrologyTechnology & Instruments: Ureteroscopy1 Apr 20101277 IN VITRO EFFICACY OF HOLMIUM:YAG LASER LITHOTRIPSY IN NON FLOATING STONES. - EFFECT OF PULSE FREQUENCY, ENERGY AND LENGTH - Felix Wezel, Christoph Hammes, Axel Haecker, Patrick Krombach, Maurice Stephan Michel, and Thorsten Bach Felix WezelFelix Wezel More articles by this author , Christoph HammesChristoph Hammes More articles by this author , Axel HaeckerAxel Haecker More articles by this author , Patrick KrombachPatrick Krombach More articles by this author , Maurice Stephan MichelMaurice Stephan Michel More articles by this author , and Thorsten BachThorsten Bach More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.848AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Holmium:YAG (Ho:Yag) laser lithotripsy is the gold standard in endoscopic stone treatment. Aim of this study was to evaluate the influence of pulse frequency, power and length on the effectiveness of Ho:Yag laser lithotripsy using two different artificial stone compositions in-vitro. METHODS Three different Ho:Yag laser devices (Sphinx, RevolixDuo (both LisaLaser, Germany) and Odyssey 30 (Cook, Ireland) were tested. The devices were used at different pulse energy rates (1 and 2 Joule) and frequency settings (5 and 10 Hz) all resulting in an output power of 10W, respectively. Where possible (Sphinx and Odyssey 30), pulse length was modified (350 vs. 700 msec). The light was transmitted via flexible 365μm fibers. Experiments were performed in a water bath using cone shaped artificial stone (20ml volume) consisting of a soft stone composition (plaster of paris; Quick-mix, Germany) and a hard stone composition (Fujirock type 4 dental stone; GC Europe, Belgium). Lithotripsy was performed for 60 sec in contact mode on fixed stones applying 600 W in total per setting. Stones were dried for 72 h; fine granulated sand was used to measure the volume of the craters. Sample size was n=10 for all settings using hard stones, and n=6 when using soft stones. Unpaired t-test was used for statistical analysis. RESULTS In all of the 5 tested groups per stone type, a slower pulse rate but increased pulse energy (5 Hz/ 2 J vs. 10 Hz/1 J) resulted in a higher stone disintegration. At 5 Hz/ 2 J Ho:Yag laser lithotripsy was more effective applied on hard stones (+ 27.46% (10-55.4%); all p < 0.05) and on soft stones (+ 33.62% (8-54.3%); 3 of 5 tested groups p < 0.05) compared to the 10 Hz/ 1 J setting. Furthermore, reduction of the pulse length from 700 to 350 msec resulted in a significantly higher stone disintegration (+ 71.58% (57-120.6%); all p < 0.05) in soft stone composition in 4 tested groups. In hard stone composition, reducing the pulse length was associated with a significant higher stone disintegration (+ 27.25% (23.8-30.7%); all p < 0.05) in combination with higher pulse energy (2 J/ 5 Hz). At lower pulse energy (1 J/ 10 Hz), the increased stone disintegration rate was not significant (+ 6,5% (6.4-6.5%), p > 0.05, respectively). CONCLUSIONS Our results indicate that higher pulse energy and shorter pulse length increase disintegration rates of Holmium:YAG laser lithotripsy when retropulsion is excluded in vitro. This may help to improve efficacy of Holmium:YAG laser lithotripsy in non floating stones in vivo. Mannheim, Germany© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e495 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Felix Wezel More articles by this author Christoph Hammes More articles by this author Axel Haecker More articles by this author Patrick Krombach More articles by this author Maurice Stephan Michel More articles by this author Thorsten Bach More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Rosen-type Pb(Mg1∕3Nb2∕3)O3–PbTiO3 single crystal piezoelectric transformer

In this study, a Rosen-type Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3) single crystal piezoelectric transformer is presented. First, we simulate the operation of this transformer using the finite element method and ANSYS. By adjusting the dimensions of the piezoelectric transformer, a maximum voltage step-up ratio of 138 can be obtained at a frequency of 33.8 kHz when the output part is open. Second, we fabricate a transformer with the size of 20 mm length, 4 mm width, and 1 mm thickness to examine the simulation results. It is found that this transformer exhibits a maximum voltage step-up ratio of 134 at 37 kHz, with the efficiency over 95% when driving a liquid crystal display backlight, which shows good consistency with the numerical simulation results. Besides, we investigate the electrical properties under different frequencies and load resistances. When the input voltage increases, a maximum output power of 1 W is obtained with the temperature rise less than 10 degrees C.