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Prototype Probe Determining Waveguidea??Gum Contact for a Robot Surgical System
摘要： A probe for cutting soft gum tissue combines a force sensor and a diode laser. In such operations, contact between the tip of the optical waveguide and the soft gum tissue must first be determined. That permits specification of the cutting trajectory in the robot control system. A probe with a diode laser and single-component force sensor is proposed. The errors regarding contact of the laser’s optical waveguide with the soft gum tissue are analyzed.
关键词： soft gum tissue,medical robots,diode laser,force sensor,dental surgery
更新于2025-09-23 15:21:01
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Laser Treatment for Melanin Gingival Pigmentations: A Comparison Study for 3 Laser Wavelengths 2780, 940, and 445a??nm
摘要： The normal appearance of the gingiva is pink to light red, and this appearance may change due to many factors and might be noticeable causing aesthetic concerns. In the Gulf area, the gingival melanin pigmentation is of the main type of concern, and patients expect the pigmentation to be removed for aesthetic reasons. Many techniques have been used to remove the melanin pigmentation such as using surgical blades, diamond or ceramic burs, chemicals, and lasers. This study is comparing the results of three lasers (Er, Cr, YSGG 2780 nm, Diode 940 nm, and 445 nm) in the removal of melanin gingival depigmentation. Clinical outcome parameters including bleeding, wound healing, pain, duration of procedure, color improvement, patient satisfaction, and relapse rate after 2 years were assessed. Conclusion. Within the limitation of this study, all three wavelengths were fast, e?ective in peeling the pigmentations and well tolerated by the patients. The esthetical results were excellent, and the patients were highly satis?ed. Suggestion. To have a bigger number of samples in future papers, and histological studies might be included to explore the di?erent impacts of each wavelength on the gingival melanin pigmentation speci?cally and on the gingival tissue generally.
关键词： aesthetic dentistry,Cr,445 nm,YSGG 2780 nm,laser treatment,Diode 940 nm,Er,melanin gingival pigmentations
更新于2025-09-23 15:21:01
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Evaluation of a Ultraviolet B Light Emitting Diode (LED) for Producing Vitamin D <sub/>3</sub> in Human Skin
摘要： Aim: A commercially available light emitting diode (LED) that transmitted narrow band ultraviolet B (UVB) radiation was evaluated for its efficacy and efficiency to produce vitamin D3 in human skin. Materials and Methods: Human skin samples were obtained from surgical procedures. The LED had peak emission wavelength of 295 nm. Skin samples were exposed to the UVB-LED for varying times and then were analyzed by high-pressure liquid chromatography (HPLC) to determine the vitamin D3 content. Results: There was a statistically significant time- and dose- dependent increase in the percent of 7-dehydrocholesterol that was converted to vitamin D3 in the skin type II samples; 1.3%±0.5, 2.3%±0.6 and 4.5%±1.67 after exposure to 0.75 (11.7 mJ/cm2), 1.5 (23.4 mJ/cm2) and 3 (46.8 mJ/cm2) minimal erythemal doses (MEDs), respectively. Conclusion: The UVB-LED was effective and efficient in generating vitamin D3 in human skin, in vitro. The amount of vitamin D3 production increased in a dose-dependent fashion with increased UVB energy. UVB-LEDs can be developed for devices that can efficiently produce vitamin D3 in human skin.
关键词： vitamin D3,human skin,ultraviolet B radiation,Previtamin D3,ultraviolet radiation light emitting diode (LED)
更新于2025-09-23 15:21:01
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Two dimensional temperature measurement characteristics in pulverized coal combustion field by computed tomography-tunable diode laser absorption spectroscopy
摘要： Two dimensional temperature and concentration distributions are important parameters for pulverized coal combustion used for power plant to understand the combustion field and develop the high efficient combustion technologies. However, it is difficult to measure two dimensional temperature and concentration in pulverized coal combustion field using conventional measurement technologies because pulverized coal combustion produces lots of dust and strong emission from its flame. This paper focused on the application of two dimensional temperature measurement method based on the combination of computed tomography and tunable diode laser absorption spectroscopy using absorption spectra of water vapor at 1388nm and 1343nm for each laser scanning using direct absorption spectroscopy, which show the better characteristics of spatial-temporal resolution, fast response, high sensitivity, self-calibration and optical accessibility. Accuracy of temperature measurement using tunable diode laser absorption spectroscopy was improved by applying the corrected spectroscopic database. Computed tomography reconstruction accuracy of 16 laser-paths configuration was evaluated using sum of squared difference (0.001) and zero-mean normalized cross-correlation (over 0.991), which presented the consistent temperature between assumed and reconstructed distributions. This developed computed tomography-tunable diode laser absorption spectroscopy was successfully applied to pulverized coal flame for two dimensional temperature measurement with 1 ms temporal resolution for time-series two dimensional temperature measurement in the range of 300K-2500K. The rationality was demonstrated by comparison of pulverized coal flame and Methane-Air flame temperature distributions due to the main heat release produced by methane fuel. Its applicability to pulverized coal combustion field will be benefit for optimal operation control and combustion efficiency improvement by combustion organization or new design of combustion system.
关键词： Power plant,Pulverized coal combustion,Computed tomography (CT),Tunable diode laser absorption spectroscopy (TDLAS),Two dimensional temperature measurement
更新于2025-09-23 15:21:01
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On the root mean square error (RMSE) calculation for parameter estimation of photovoltaic models: A novel exact analytical solution based on Lambert W function
摘要： In the literature, one can find a lot of methods and techniques employed to estimate single diode solar photovoltaic (PV) cell parameters. The efficiency of these methods is usually tested by calculating the Root Mean Square Error (RMSE) between the measured and estimated values of the solar PV cell output current. In this work, first, the values of RMSE calculated using 69 different methods published in many journal papers for the well-known RTC France solar PV cell are presented and discussed. Second, a novel exact analytical solution for RMSE calculation based on the Lambert W function is proposed. The results obtained show that the RMSE values were not calculated correctly in most of the methods presented in the literature since the exact expression of the calculated cell output current was not used. Third, the precision of calculation of the methods used for analytical solving of Lambert W equation is presented and discussed. Fourth, the applicability of the proposed solution methodology in accordance with current-voltage characteristics measured in the laboratory for solar modules of Clean Energy Trainer Setup is checked. Identification of its unknown parameters is presented using three optimization techniques. Further, the proposed solution methodology is proven for Solarex MSX–60 PV module, and the most promising 5-parameter single diode parameters are estimated based on minimization of the precise RMSE values calculated. Finally, this work aimed to develop a good base for proper investigation and implementation of optimization algorithms to solve the parameter estimation problem of 5-parameter single diode PV equivalent circuits.
关键词： Root mean square error,5-parameter single diode model,PV parameter estimation,Optimization,RTC France solar cell,Lambert W function
更新于2025-09-23 15:21:01
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Diode laser surgery versus electrocautery in the treatment of inflammatory fibrous hyperplasia: a randomized double-blind clinical trial
摘要： Objectives To compare the efficacy and safety of diode laser and electrocautery techniques for inflammatory fibrous hyperplasia (IFH) removal. Materials and methods In this randomized double-blind clinical trial, 40 individuals were randomly allocated to two groups: group 1 (G1) consisted of 20 individuals assigned to treatment with diode laser and group 2 (G2) consisted of 20 individuals assigned to treatment with electrocautery. The following transoperative parameters were evaluated: bleeding, temperature, and surgical technique parameters (energy deposited on tissue, flow rate, and time of incision). The postoperative parameters evaluated were as follows: pain, functional alterations (chewing, speaking), analgesic medication intake, swelling, healing of the wound area, and patient satisfaction. Results Among the 40 individuals included in the study, four (two in G1 and two in G2) did not complete the entire follow-up. Therefore, 36 individuals (18 in G1 and 18 in G2) participated. Participants in G1 and in G2 had similar demographic characteristics. No difference regarding the trans- or postoperative parameters evaluated was observed between G1 and G2 (p > 0.05). Also, no difference regarding the time for healing was observed between groups. Conclusions Diode laser seems to be as effective and safe as electrocautery when applied under similar conditions for IFH removal. Clinical relevance IFH corresponds to 65% of the lesions observed in denture wearers. This study shows that under similar conditions diode laser is as effective and safe as electrocautery for removal of IFH.
关键词： Cautery,Clinical trial,Hyperplasia,Diode laser
更新于2025-09-23 15:21:01
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Carbazole-modified polyphenylene ether as host materials for high efficiency phosphorescent organic light-emitting diodes
摘要： Two novel polymeric hosts called PPO-Cz and PPO-3Cz for solution-processed green phosphorescent organic light-emitting devices have been designed and synthesized by incorporating electron-donor carbazole units with polyphenylene ether. In order to simplify the synthesis route and save cost, we attached the classic carbazole units directly to the side chain of the polyphenylene ether. This molecular design endows these two polymeric hosts with good thermal stability and high triplet energy levels. PPO-Cz- and PPO-3Cz-based emissive-layer green phosphorescent organic light-emitting diodes were fabricated with simplified device configuration by solution-processed using Ir(mppy)3 as a dopant. These devices exhibited lower turn on voltages. Moreover, the PPO-3Cz-based solution processed device showed maximum current efficiency and external quantum efficiency of 31.8 cd/A and 9.3%, respectively. This result demonstrated that the newly synthesized, polymeric hosts were advantageous for fabrication of highly efficient green phosphorescent organic light-emitting diodes.
关键词： Organic light emitting diode,Polyphenylene ether,Modify,Carbazole,Polymeric host
更新于2025-09-23 15:21:01
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Analysis and design of a multi-channel constant current LED driver based on DC current bus distributed power system structure
摘要： In this paper, we have extensively investigated the impact of anode recess on the reverse leakage current, forward voltage (VF), and dynamic characteristics of Au-free AlGaN/GaN Schottky barrier diodes with a gated edge termination (GET-SBDs) on 200-mm silicon substrates. By increasing the number of atomic layer etching (ALE) cycles for anode recessing, we have found that: 1) the reverse leakage current is strongly suppressed due to a better electrostatic control for pinching off the channel in the GET region; a median leakage current of ～1 nA/mm and an ION/IOFF ratio higher than 108 have been achieved in GET-SBDs with six ALE cycles; 2) the forward voltage (～1.3 V) is almost independent of the ALE cycles, taking into account its statistical distribution across the wafers; 3) when the remaining AlGaN barrier starts to be very thin (in the case of six ALE cycles), a spread of the ON-resistance, mainly attributed to the GET region, can occur due to the dif?cult control of the remaining AlGaN thickness and surface quality; and 4) the dynamic forward voltage of GET-SBDs shows a mild dependence on the ALE process in pulsed I–V characterization, and a more ALE-dependent dynamic ON-resistance is observed.
关键词： atomic layer etching (ALE),200-mm,leakage,metal–insulator–semiconductor high-electron mobility transistor (MISHEMT),GET-SBD,diode,AlGaN/GaN
更新于2025-09-23 15:21:01
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[IEEE 2020 Moscow Workshop on Electronic and Networking Technologies (MWENT) - Moscow, Russia (2020.3.11-2020.3.13)] 2020 Moscow Workshop on Electronic and Networking Technologies (MWENT) - Measurement of the Dynamic Characteristics of Separate Spectral Bands of the LEDs Electroluminescence Spectra
摘要： A method for measuring the 3 dB frequency of the full modulation of separate spectral components of electroluminescence spectrum of light-emitting diodes (LEDs) is described. The method consists in passing through the LED a series of current pulses having the shape of a meander, and the emission spectrum of the LED is measured by a spectrometer OceanOptics USB2000+ in the mode of signal accumulation. As the pulse frequency increases, the intensity of all spectral components of the LED emission spectrum decreases. The frequency at which the optical signal decreases 1.19 times relative to the level measured at a low frequency is taken as the 3 dB frequency of the separate spectral component of the LED electroluminescence spectrum. By using the pulse signal it is possible to increase the sensitivity of the measuring means compared to the measuring means using the harmonic test signal. A description of the hardware-software complex implementing said measurement method is presented. The results of testing the measuring complex by the electroluminescence spectra of commercial green InGaN-based LEDs at the current range of 10-5...10-2 A and the current frequency range of 0.001...10 MHz are presented. The developed hardware-software complex and the method for estimating the spectral recombination parameters of heterojunction LEDs can be used both for the purpose of diagnosing the quality of LEDs and in developing structural and technological solutions for creating new light-emitting structures.
关键词： electroluminescence spectra,measuring complex,measurement method,3 dB frequency,light-emitting diode (LED),radiative and nonradiative charge carriers lifetime
更新于2025-09-23 15:21:01
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[IEEE 2018 15th IEEE India Council International Conference (INDICON) - Coimbatore, India (2018.12.16-2018.12.18)] 2018 15th IEEE India Council International Conference (INDICON) - Safety of Light Emitting Diode (LED) Based Domestic Lighting in Rural Context
摘要： As per 2011 census, 69% of Indians live in the rural settings, who are primarily dependent on subsistence agriculture. Rural house-holds use power lighting, operating household appliances and agricultural works. Home-lighting is one of the major components of power consumption in less affluent rural households. Many rural houses use kerosene lamps, lanterns, candles and inverter-based electric lamps as a light source. Therefore, artificial lighting in a rural scenario is expected to have certain characteristics such as a) illumination; b) Low cost; c) Low power appropriate consumption; d) Long life; e) Low maintenance. Light-emitting Diode (LED) has been a revolution in such scenarios with its long life, low cost, less power consumption and lesser pollution. While nowadays, low-cost white (cool daylight) LED lights have overtaken the Indian lighting market and are projected to reach $2.2billion by 2021. However, some reports have raised concern regarding various health hazards (circadian rhythm disruption and harm to the human eyes) due to sharp blue-peak in LED lights. Since the scientific literature is still inconclusive about the photo-biological safety of blue-rich white LEDs, usage of LEDs needs more awareness. The aim of this study is to assess the fraction of radiation in the blue region of the entire spectrum of white LED lights and propose low-cost filters to reduce the blue-rich components of LED lighting.
关键词： Domestic Lighting,Rural Context,Light-Emitting Diode
更新于2025-09-23 15:21:01