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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • sodium lighting system
  • modeling
  • radiation curves
  • LED lighting system
  • software goniophotometer
  • upper half-space
应用领域
  • Electrical Engineering and Automation
机构单位
  • VSB-TU Ostrava
91 条数据
?? 中文（中国） ▾

  • Antimicrobial Efficacy of Photodynamic Therapy, Diode Laser, and Sodium Hypochlorite and Their Combinations on Endodontic Pathogens

    摘要： Background: Sterilization of the root canal system is of prime importance for a successful root canal therapy. Lasers and photodynamic therapy (PDT) have become the latest choice to eradicate microorganisms in the root canal. Objective(s): To evaluate and compare the antimicrobial activity of diode laser, photodynamic therapy, and sodium hypochlorite along with their combinations on endodontic pathogens: Enterococcus faecalis and Streptococcus mutans. Methods: A total of 120 uniradicular teeth were stored in 5.2% NaOCl solution to remove organic residues and the crowns were sectioned at the cemento-enamel junction (CEJ) to obtain root canal length of 15 mm. Canals were shaped using step-back technique up to #40 K-file and were autoclaved. The selected teeth (specimen) were randomly divided into two equal groups with sixty root canals inoculated with E. faecalis (Group E) and remaining sixty teeth with S. mutans (Group S). Further, the groups were subdivided according to the disinfection technique used. Ten teeth from each subgroup were disinfected with a diode laser, photo activated disinfection (PAD), sodium hypochlorite, a combination of sodium hypochlorite and diode laser, a combination of sodium hypochlorite and PAD respectively. Ten teeth in each group served as control without any disinfection. The treated specimens were transferred to test tubes containing 5ml sterile Luria Bertani broth, incubated and the bacterial count, optical density in each root specimen was calculated and compared. The pairwise comparison of colonies across the subgroups was done by the Kruskal-Wallis test and within the subgroups was carried out using the Mann-Whitney U test. The statistical implication was tested at 5% and the study was performed using SPSS 18.0 ver. (SPSS Inc.). Results: A significant reduction (98%) in the E. faecalis count was observed when the NaOCl was used in combination with the diode laser or PAD. PAD along with 3% NaOCl presents the advantage of utilizing a lower wavelength laser beam. Hence, PAD in combination with NaOCl can be an alternative and better option for root canal disinfection for both the endodontic pathogens, E. faecalis and S. mutans.

    关键词： E. faecalis,disinfectant,PDT,sodium hypochlorite,PAD,photodynamic therapy,Diode laser,S. mutans

    更新于2025-09-16 10:30:52

  • Facile synthesis of heteroatom doped and undoped graphene quantum dots as active materials for reversible lithium and sodium ions storage

    摘要： Zero-dimensional graphene quantum dots have attractive properties but the synthesis of graphene quantum dots in a simple and scalable technique is tedious, which limits its utilization in different energy storage application. In this study, we present a simple and scalable approach to produce graphene quantum dots and heteroatom doped graphene quantum dots using chemical vapor deposition technique. Graphene quantum dots are prepared using alloy-based catalyst and methane as a carbon source. Boron-doped and nitrogen-doped graphene quantum dots are prepared at low temperature using graphite oxide without the use of dialysis bag. Here, the electrochemical lithium and sodium ion storage properties of doped and undoped graphene quantum dots are studied without being used as a supporting material for the performance enhancement as reported in previous reports. Boron doped GQD (B-GQD) exhibits a high specific capacity of 1097 mAh g?1 at a specific current of 50 mA g?1 for lithium and sodium ion batteries respectively. B-GQD exhibits high volumetric energy density of 537 Ah L?1 and 214 Ah L?1 with an average voltage of 0.43 V and 0.57 respectively for lithium ion and sodium ion batteries. Also, the cells observe a satisfactory cyclic performance for 500 cycles with good capacity retention. Detailed investigations show that the edge defects present in GQD and doped GQDs help to enhance the electrochemical storage performance of lithium and sodium ions.

    关键词： Doped,Lithium ion battery,Quantum dots,Sodium ion battery,Anode material

    更新于2025-09-12 10:27:22

  • Effect of up-conversion luminescence in Er3+ doped phosphate glasses for developing Erbium-Doped Fibre Amplifiers (EDFA) and G-LED's

    摘要： The (NPbPEr) glasses of the composition (20-x) Na2SO4-20PbO-60P2O5-xEr2O3 (x= 0.1, 0.3, 0.5, 0.7, 1.0 mol %) are synthesized by melt quenching process. The basic characterization studies like XRD and EDS have confirmed amorphous nature and contents of the samples. The spectroscopic studies viz., optical absorption, photoluminescence (PL) and decay profiles were carried out. The PL spectra exhibited an intense sharp green emission peak at 544 nm due to 4S3/2 → 4I15/2 transition of Er3+ ions both in down-conversion (DC, l exc = 377 nm) and up-conversion (UC, l exc = 977 nm) PL spectra. The spectra also exhibited a broad intense NIR band at 1532 nm ascribed to 4I13/2→4I15/2 transition of Er3+ ions at l exc = 977 nm. The analysis of the spectra indicated 0.5 mol% of Er2O3 is the optimal concentration for achieving maximal PL output both in the green and in NIR regions. The CIE color coordinates and the corresponding CCT (K) values were estimated from both UC and DC emission spectra. Overall analysis of the results suggested that the investigated glasses are potential candidates for getting intense green light emission and are quite suitable as optical fibre amplifiers in the green and NIR (around 1.5 m m) regions.

    关键词： Er3+ ions,Green and NIR emission,sodium sulfo-phosphate glasses

    更新于2025-09-12 10:27:22

  • Reflection Spectra of Composite Photonic Crystals Based on Anodic Alumina Filled with Ferroelectric Sodium Nitrite

    摘要： Re?ection spectra of a composite one-dimensional photonic crystal (PC) based on porous anodic alumina ?lled with ferroelectric sodium nitrite have been recorded in the wavelength range of 400 to 1200 nm. Signi?cant spectral shifts of the ?rst and second stopbands are revealed for the composite PC. The stopband spectral half-width is found to decrease by a factor of four to ?ve. The possibility of applying composite alumina-based photonic crystals as selective narrowband mirrors is discussed.

    关键词： reflection spectra,ferroelectric sodium nitrite,photonic crystals,anodic alumina,stopbands

    更新于2025-09-12 10:27:22

  • Separation Between Silicon and Aluminum Powders Contained Within Pulverized Scraped Silicon-Based Waste Solar Cells by Flotation Method

    摘要： There are few study examples on the separation of metals by floating method. In this study, separation of silicon and aluminum, which are the main components of silicon-based solar cell module, was carried out by floating method in order to purify silicon from waste solar cell module. The selection of surfactant, control of electric charge, wettability of the solid particles, surface tensions, and bubble surface area are important for separation of solids by floating method. Sodium dodecyl sulfate (SDS) can increase the hydrophobicity of aluminum powder due to the difference of surface potentials between silicon and aluminum. SDS behaves as a collector of aluminum as well as a frothing agent to decrease the bubble size. At a SDS concentration of 2 g/L and sample dipping time of 10 min, 80.1 mass% of aluminum was floated and separated, and the sedimentary silicon reached a purity of 90.7% from a mixture of 50 mass% aluminum and 50 mass% silicon. Finally, at a pH value of 7.0, SDS concentration between 1.0 and 2.5 g/L and air flow rate of 2.5 L/min (STP) were suitable experimental conditions to purify silicon from a mixture of silicon and aluminum by flotation separation method.

    关键词： Floating separation,Silicon,Flotation,Sodium dodecyl sulfate,Waste solar cell module

    更新于2025-09-12 10:27:22

  • <i>Candida albicans</i> Sterilization Using a Light-Emitting Diode and Methylene Blue

    摘要： Background and aims: Conventional fungal treatment using external medication requires considerable time and effort. We herein examined the basic effect of methylene blue (MB) with sodium bicarbonate (NaHCO3) on Candida albicans sterilization using photodynamic antimicrobial chemotherapy (PACT). Materials and methods: NaHCO3 was added to MB to establish a basic pH. Then, C. albicans was smeared on a medium with basic MB followed by irradiation using a red light-emitting diode (LED) with a wavelength of 660 nm. The applied energy fluencies were 5, 10, 15, and 20 J/cm2. After 48 h of culture, the effects of the intervention were determined according to the fungal growth area. Results: The basic effect appeared at a pH range of 8.6 to 8.9 and at 10 and 15 J/cm2, while the NaHCO3 concentration was between 1% and 2%. Conclusions: Our results suggested that PACT using basic MB was effective for C. albicans sterilization.

    关键词： C. albicans,basic effect,methylene blue,LED,PACT,sodium bicarbonate

    更新于2025-09-11 14:15:04

  • Dynamic Color-Switching of Plasmonic Nanoparticle Films

    摘要： The fast and reversible switching of plasmonic color holds great promise for many applications, while its realization has been mainly limited to solution phases, achieving solid-state plasmonic color-switching has remained a significant challenge owing to the lack of strategies in dynamically controlling the nanoparticle separation and their plasmonic coupling. Herein, we report a novel strategy to fabricate plasmonic color-switchable silver nanoparticle (AgNP) films. Using poly(acrylic acid) (PAA) as the capping ligand and sodium borate as the salt, the borate hydrolyzes rapidly in response to moisture and produces OH? ions, which subsequently deprotonate the PAA on AgNPs, change the surface charge, and enable reversible tuning of the plasmonic coupling among adjacent AgNPs to exhibit plasmonic color-switching. Such plasmonic films can be printed as high-resolution invisible patterns, which can be readily revealed with high contrast by exposure to trace amounts of water vapor.

    关键词： plasmonic color-switching,nanoparticles,silver,films,sodium borate

    更新于2025-09-11 14:15:04

  • Development of solid polymer electrolytes based on sodium-carboxymethylcellulose (NaCMC)-polysulphide for quantum dot-sensitized solar cells (QDSSCs)

    摘要： Sodium-carboxymethylcellulose (NaCMC) films have been developed by solution casting technique. The films were soaked into an optimized aqueous polysulphide electrolyte containing 4 M sodium sulphide (Na2S) and 1 M sulphur (S). The optimized aqueous polysulphide electrolyte has the ambient conductivity of (1.46 ± 0.02) × 10-1 S cm-1. The NaCMC films were soaked for different durations of 30, 60, 68 and 75 s. The highest room temperature ionic conductivity (RTIC) of (2.79 ± 0.09) × 10-5 S cm-1 is exhibited by NaCMC film soaked in polysulphide electrolyte for 68 s. The conductivity-temperature relationship of NaCMC-based polysulphide solid polymer electrolytes (SPEs) follows the Arrhenius rule. The highest conducting SPE exhibits the lowest activation energy (EA) value of 0.38 eV. Ionic coefficient of diffusion (D), ionic mobility (μ) and free ions concentration (n) of the SPEs were determined. The newly developed SPEs are used as electrolyte in quantum dot-sensitized solar cells (QDSSCs) application with the configuration FTO/TiO2/CdS/ZnS/SPE/Pt/FTO. Under 1000 W m-2 illumination, QDSSC with CMC-68 SPE exhibits the highest power conversion efficiency (PCE) of 0.90%. The values of short circuit current (JSC) and PCE are closely related to electron lifetime and recombination rate.

    关键词： Solid polymer electrolyte,Sodium-carboxymethylcellulose,Quantum dot-sensitized solar cells,Transport properties,Polysulphide

    更新于2025-09-11 14:15:04

  • Realization of GaN-based gain-guided blue laser diodes by helium ion implantation

    摘要： Na4MnV(PO4)3 (denoted as NMVP) has drawn increasing attention owing to the three-dimensional framework and high theoretical capacity. Nevertheless, the inherent low electronic conductivity of NMVP impedes the scale-up commercial applications. In this work, the feasibility to achieve ultrahigh-rate capability and long lifespan by in situ embedding the intertwined carbon nanotube (CNT) matrix into the bulk of Na4MnV-(PO4)3@C composites through a facile wet-chemical approach is reported. The elaborately prepared Na4MnV(PO4)3@C@CNTs cathode delivers a discharge capacity of 109.9 mA h g?1 at C/5 with an impressive rate capability of 68.9 mA h g?1 at an ultrahigh current rate of 90 C as well as a fascinating cycling performance of 68.3% capacity retention at 40 C after 4000 cycles. The optimum design of the 3D well-interconnected NMVP permitting fast kinetics for transported Na+/e? is bene?cial to the excellent electrochemical performance, which is further studied by the galvanostatic intermittent impedance spectra measurements. The pseudocapacitance contributions are also investigated. The research demonstrates that the dual-nanocarbon synergistically modi?ed NMVP composite is expected to facilitate the commercialization of sodium-ion batteries.

    关键词： Na4MnV(PO4)3,sodium-ion batteries,ultrahigh-rate capability,long lifespan,CNTs

    更新于2025-09-11 14:15:04

  • Laser-stimulated piezo-optical and third harmonic generation studies for Na2O–Sb2O3 glass ceramics-influence of gold ions

    摘要： Sodium antimonate glass ceramics with different concentrations of Au2O3 were synthesized. The prepared samples were characterized by XRD, XPS, SEM and TEM techniques. These studies have revealed that the samples consist of multiple crystalline phases composed of Sb3+, Sb5+, Au3+ ions, and Au0 particles; moreover these studies have indicated growing proportion of Au0 particles and Sb5+crystal phases (Na2Sb2O6) with increase of Au2O3 concentration. IR and Raman spectral studies have pointed out an increasing degree of polymerization of the glass network with increase of Au2O3 content while optical absorption studies indicated surface plasmon resonance effects. Nd: YAG laser (λ = 1320?nm and pulse width 8?ns) was used for inducing third harmonic generation (THG) signal. Later, THG signal intensity of Nd: YAG laser (λ = 1064?nm and pulse width of 20?ns) vs fundamental beam power density was recorded. The results indicated the maximum intensity for the samples containing a low concentration of Au2O3. For inducing piezo-optical effects, Nd: YAG laser (λ = 1064?nm) and its doubled frequency beam λ = 532?nm (with simultaneous mechanical pressure) were used. The cw He-Ne laser of 20?mW (with beam diameter about 0.5?mm) was used as probing beam for measuring the piezo-optical effects in the photo-polarized samples. The variation of the intensity of the THG beam and piezo-optical coefficients were found to be the maximal for the samples mixed with small quantities of Au2O3. The detailed analysis of XRD, SEM, EPR, IR, optical absorption spectral results suggested that concentrations of Na3SbO3 and also Au2O3 crystal phases are maximal in these?samples and are responsible for the maximal photoinduced effects, while the increasing presence of Na2Sb2O6 crystal phases and Au0 metallic particles are found to be hindrance for generation of third harmonic beams and also piezo-optical effects. Overall, the obtained results of nonlinear optical (NLO) and piezo-optical studies indicated that Na2O-Sb2O3 glass ceramics containing small traces of Au2O3 are useful for considering them for nonlinear optical triggering devices and piezo-electric devices.

    关键词： Sodium antimonate glass ceramics,piezo-optical effects,Nd: YAG laser,Au2O3,third harmonic generation

    更新于2025-09-11 14:15:04