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Advances in GaN Crystals and Their Applications
摘要： This special issue looks at the potential applications of GaN-based crystals in both ?elds of nano-electronics and optoelectronics. The contents will focus on the fabrication and characterization of GaN-based thin ?lms and nanostructures. It consists of six papers, indicating the current developments in GaN-related technology for high-ef?ciency sustainable electronic and optoelectronic devices, which include the role of the AlN layer in high-quality AlGaN/GaN heterostructures for advanced high-mobility electronic applications and simulation of GaN-based nanorod high-ef?ciency light-emitting diodes for optoelectronic applications. From the results, one can learn the information and experience available in the advanced fabrication of nanostructured GaN-based crystals for nano-electronic and optoelectronic devices.
关键词： MOSFET,AlN,InN,InGaN,AlGaN,LED,GaN
更新于2025-09-23 15:21:21
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A Lifetime Performance Analysis of LED Luminaires Under Real-Operation Profiles
摘要： Light-emitting diode (LED)-based lighting is the most dominant lighting solution in the current era since it is energy-efficient and long-lasting. Hence, performance analysis of the LEDs throughout its lifetime is of prime importance. The work presented in this article provides insight on degradation analysis of the LED luminaire inclusive of the LED driver in real operating ambient conditions and investigates the performance of both LED light engine and LED driver throughout the period of its lifetime. To represent the practical scenario of LED lighting system usage in commercial applications, analysis of switching cycles on the performance of LED luminaires is also studied. The outcome of this article suggests that LED luminaire under study tends to fail due to lumen degradation, followed by color shift represented by Duv and then lastly by driver failure. Scanning electron microscope and energy-dispersive spectroscopy (SEM-EDS) analysis suggests the corrosion of Ag mirror resulting in lumen output reduction and, thus, is the main reason for the failure of LED luminaire. This provides an insight into the LED manufacturing companies to have better estimate on lifetime of LED luminaires and also the necessity to improve the LEDs’ performance such that luminaires will have longer lifetime as claimed.
关键词： Life estimation,operating cycles,light-emitting diode (LED) luminaire,lumen degradation
更新于2025-09-23 15:21:01
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Magneto-LED therapy in the treatment of inflammatory lesions and erosions of the glans penis a?? case report
摘要： Introduction. Inflammatory lesions and erosions of the glans penis defined as balanitis or balanoposthitis constitute a disease in which the effectiveness of conservative treatment is not sufficient. Objective. To present the therapeutic efficacy of magneto-LED therapy in the treatment, and to present a patient with inflammatory lesions and erosions of the glans penis. Case report. The patient, 68 years old with inflammatory lesions and erosions of the glans penis of 2–4 years duration, was previously treated with various methods of local therapy without effect. As a result of a 32-week long magneto-LED therapy cycle, complete resolution of skin lesions with subsidence of the burning sensation during urination and reduced swelling and inflammatory erythema of the glans, as well as disappearance of the white coating and unpleasant smell, was achieved. Conclusions. Magneto-LED therapy is an efficient method of treatment of inflammatory lesions and erosions of the glans penis.
关键词： glans penis,alternative treatment,magneto-LED therapy
更新于2025-09-23 15:21:01
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Color conversion properties of various thick-film phosphor-in-glasses depending on structural design for white LEDs
摘要： Thick-film phosphor-in-glasses (PiGs) were fabricated via a screen-printing method with various phosphor layer structures, to compose a white LED. Green (Lu3Al5O12:Ce3+) and red (CaAlSiN3:Eu2+) phosphors were mixed, layered and patterned on a glass substrate. The chromaticity of each structured PiG was tuned to achieve a white LED by varying phosphor content and thickness. The emission spectra and the related various color conversion properties, including color coordinates, correlated color temperature (CCT), color rendering index (CRI), luminous efficacy (LE) and the color gamut of the mounted PiGs with different phosphor layer structures were examined and compared. Time-resolved photoluminescence (TRPL) measurements of the white LEDs with various phosphor layer structural designs were also obtained and compared. It was observed that spectral variation depended on the PiG layer structure. A proper PiG layer structural design was discussed for practical applications.
关键词： glass,thick films,LED,Phosphors
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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Tunable spectrum resemblance of LED lights for improving the photosynthetic action of Chinese Cabbages
摘要： To increase efficiency, and reduce energy loss and waste, we propose to improve the photosynthetic action spectrum resemblance (SRPAS) of LED light with the absorption spectra of the fresh leaf, for accelerating the growth of Chinese Cabbages. Eight spectral LED lights were adopted to irradiate Chinese Cabbages under 150 μmol·m-2·s-1 for a 16 hd-1 photoperiod. Of these, under the irradiation of blue + broad red + more yellow (BRY2) light with high spectrum resemblance of 75%, the fresh weight and dry weight are 5.1times and 3.0 times, respectively, and the leaf area and leaf number are 1.7 times, as high as under the blue light. The results demonstrate that the optimized LED light can be presumed to have the highest spectrum resemblance (SRPAS) with the absorption spectra of Chinese Cabbages, and the highest energy-conversion efficiency. These conclusions may be of great benefit to further assess and find either an ideal light applied for plant growth or design of better light sources for growing different plants.
关键词： Absorption spectrum,Photosynthetic action spectrum resemblance,LED lighting,Growth and morphology,Chinese Cabbages
更新于2025-09-23 15:21:01
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Photoelectrochemical-assisted batch injection analysis (PEC-BIA) of glucose exploiting visible LED light as an excitation source
摘要： This work describes the development of a novel method for glucose determination exploiting a photoelectrochemical-assisted batch injection analysis cell designed and constructed with the aid of 3D printer technology. The PEC-BIA cell was coupled to a LED lamp in order to control the incidence of light on the Cu2O/Ni(OH)2/FTO photoelectroactive platform. The electrochemical characteristics of Cu2O/Ni(OH)2/FTO photoelectroactive platform were evaluated by cyclic voltammetry, amperometry, and electrochemical impedance spectroscopy. The PEC-BIA cell presented linear response range, limit of detection based on a signal-to-noise ratio of three, and sensitivity of 1 – 1000 μmol L-1, 0.76 μmol L-1 and 0.578 μA L μmol-1, respectively. The PEC-BIA method presented a mean value of the recovery values of 97.0 % to 102.0 % when it was applied to glucose determination in artificial blood plasma samples which indicates the promising performance of the proposed system to determine glucose.
关键词： Photoelectrochemistry,Visible LED light,Glucose,Batch injection analysis,3D-Printing,Cu2O/Ni(OH)2
更新于2025-09-23 15:21:01
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Degradation of Ciprofloxacin and Inactivation of Ciprofloxacin Resistant E. Faecium during UV-LED (275 nm)/Chlorine Process
摘要： Ciprofloxacin and ciprofloxacin-resistant bacteria are emerging concerns that threaten public health due to the heavy use of antibiotics and the development of bacterial resistance in water environments. In this study, we examined an energy-efficient treatment driven by a UV-LED/chlorine reaction with UV-LED chip emitting UV275 nm to remove ciprofloxacin and ciprofloxacin-resistant bacteria in water. Ciprofloxacin degradation during the UV-LED/chlorine reaction followed pseudo-first-order kinetics, and the excessive chlorine dosage has a negative effect on ciprofloxacin removal. Alkaline pH showed the best efficiency for ciprofloxacin removal, and the reactive chlorine species (RCS) played a major role at alkaline pH values. The cleavages of piperazine, cyclopropyl, and quinolone moieties are considered as the principal degradation reactions in the UV-LED/chlorine reaction. Seven byproducts (m/z = 362.9262, 306.1246, 289.0995, 288.1504, 263.0825, 147.0657, and 1183.9977), two chlorinated compounds (chloroform and chlorate) and two anions (formate and nitrate ions) were observed as the identified byproducts. Toxicity of tentatively identified byproducts were estimated by using quantitative structure activity relationship (QSAR). The complete detoxification of D. magna was achieved when applying UV-LED/chlorine process into hospital wastewater containing CIP. The UV-LED/chlorine process showed the best disinfection ability of E. faecium compared to UV-LED photolysis, chlorination, and UV-LED/H2O2 reactions. A significantly lower EE/O value (6.63 × 10-2 kWh/m3/order) during the UV-LED/chlorine reaction was also observed. Our results indicate that the UV-LED/chlorine process can effectively degrade ciprofloxacin and inactivate ciprofloxacin-resistant bacteria.
关键词： toxicity,UV-LED,ciprofloxacin,byproducts,antibiotic-resistant bacteria,Chlorine
更新于2025-09-23 15:21:01
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Blue LED light-driven photoelectrocatalytic removal of naproxen from water: Kinetics and primary by-products
摘要： Here, we demonstrate the viability of a ZnO/TiO2/Ag2Se thin-film composite synthesized on FTO to degrade the drug naproxen in aqueous solutions by visible-light photoelectrocatalysis (PEC). The experiments were made with 100 mL of solutions containing 5 mg L-1 drug and 50 mM Na2SO4 at natural pH, using a cell equipped with a Pt wire as cathode and the composite as photoanode exposed to a 36 W blue LED lamp. Total degradation was achieved after 210 min of electrolysis at anodic potential of +1.0 V/Ag|AgCl. This resulted from the oxidative action of hydroxyl radicals formed via direct anodic water discharge and through mediated water oxidation by photogenerated holes. The degradation rate decreased at higher naproxen concentration, but the treatment efficiency became higher due the deceleration of the parasitic reactions involving hydroxyl radicals. In chloride medium, the photoanode showed a large ability to produce active chlorine, which contributed to the oxidation of the target molecule. LC-QToF-MS analysis of treated solutions revealed the generation of four primary naphthalenic by-products, from which the initial degradation route of naproxen is proposed.
关键词： Photoelectrocatalysis,Water treatment,Oxidation by-products,Blue LED light,Pharmaceutical residue
更新于2025-09-23 15:21:01
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Synthesis and photoluminescent properties of Ba2+ ions doped europium formate phosphors for white light-emitting diodes
摘要： We report on the synthesis and photoluminescent performance of the Ba2+ ions doped Eu(HCOO)3 phosphors as well as their promising applications in indoor illumination. The thermal stability of the synthesized sample with microparticles was characterized by the thermogravimetric analysis. Irradiated by 396 nm light, the unique emissions of Eu3+ ions originating from the 5D0 → 7FJ (J ? 1, 2, 3, 4) transitions were observed. With the aid of the Judd-Ofelt theory, the local symmetry properties of the Eu3+ ions in the selected host were studied, revealing that the sites taken by the Eu3+ ions possessed low symmetry with non-inversion center. An enhanced luminescent intensity was seen in the resultant phosphors when the Ba2+ ions were introduced and the optimal doping content was 10 mol%. The studied samples can exhibit bright visible red emission with high color purity of 93.3% upon 396 nm excitation. Moreover, the resistance of the emission intensity to the temperature was also explored and the activation energy was 0.188 eV. Furthermore, the internal quantum efficiency of the resultant samples was 67% when excited by 396 nm. Ultimately, a light-emitting diode (LED) lamp, which emitted warm white light with high color rendering index of 80.7 and low color correlated temperature of 4715 K, was constructed, indicating the feasibility of the synthesized phosphors for white-LED.
关键词： Phosphors,White-LED,Luminescence,Rare-earth ion
更新于2025-09-23 15:21:01