Color Light-emitting Diode Research Articles

Morphological changes and antioxidative capacity of jute (Corchorus capsularis, Malvaceae) under different color light-emitting diodes

Light quality is an important environmental factor controlling plant growth and development. On the other hand, jute (Corchorus capsularis L.) (jute) is sensitive to light quality and the factory production of C. capsularis for vegetable use and for transplanting in the field requires an investigation of the responses of C. capsularis to light quality. For this purpose, a pot experiment was conducted to investigate the effect of different color light-emitting diodes (LED) on growth, chlorophyll contents, reactive oxygen species (ROS) production and antioxidative defense system in C. capsularis under glasshouse environment. Different light-emitting diodes were used in this study: white light (WL), red light (RL), dark red light (DL), mixed dark red light (ML), blue light (BL) and orange light (OL). Results showed that RL, DL and ML significantly (P ≤ 0.05) increased plant height, crown length and plant biomass as compared with control (WL). All red-light spectrum, i.e., RL, DL and ML, improved leaf development, but decreased malondialdehyde (MDA) and proline contents as well as activity of superoxide dismutase (SOD) and peroxidase (POD). Meanwhile, chlorophyll contents were also augmented. In contrast, BL and OL reduced plant growth, biomass, chlorophyll contents and increased activities of SOD, POD, content of proline, MDA, and reduced the total soluble protein which suggested that plants grown under BL and OL undergo high environmental stress. These results depicted that all red lights, i.e., red, dark red, mixed red lights, can be effectively implemented for industrial production of C. capsularis.

STUDY ON VISION-BASED MULTIDIRECTIONAL POSTURE AND MOTION ANALYSIS SYSTEM DEVELOPMENT

In this study, a multidirectional posture and motion evaluation tool system using a camera-based vision system was developed. By installing a camera on the top, back, left, and front of the system, kinematical information of the participant was collected and analyzed on the sagittal, coronal, and transverse planes. A dedicated color light-emitting diode (LED) marker was developed for increasing recognition rate of marker. Based on LabVIEW, images collected from four cameras were printed on one screen, and the detection angle of each marker was calculated using the cosine second law. To evaluate the performance of this system, a motion analysis experiment was performed on 20 office workers in Jeonju area. The reliability was measured using POFOMO, Dartfish and the results were compared. The comparison results indicate that the concurrent validities of the two results for the knee angle, left shoulder, and right shoulder were highly correlated as [Formula: see text], 0.988, and 0.991, respectively. Because the POFOMO image analysis tool in the present system reduces the analysis time and involves a simpler measurement procedure than that of Dartfish, this system can be used as an effective device for measuring the posture alignment of the human body.

Effects of Different Colored LEDs on the Enhancement of Biologically Active Ingredients in Callus Cultures of Gynura procumbens (Lour.) Merr.

Conventional fluorescent lamps that are used in tissue culture are costly light sources, exhibiting excessive wavelength emission-bandwidth that must be replaced by alternative, less costly, and much lower power-consuming energy sources. The use of Light-Emitting Diodes (LEDs) is the best option due to their potential role as elicitors of secondary metabolite production in many plant models. Gynura procumbens (G. procumbens) is widely used for treating various diseases. Here, leaf explants were cultivated in MS medium that was supplemented with 0.5 mg/L of naphthaleneacetic acid (NAA) and 2.0 mg/L of benzylaminopurine (BAP) for 30 days under white, blue, and red LEDs. Secondary metabolites were analyzed by High Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (LC-MS). Blue LEDs elicited the highest antioxidant activity, total flavonoid, and phenolic content. Furthermore, the content of cyanidin-monoglucosides significantly increased under blue light.

Validation of corneal topographic and aberrometric measurements obtained by color light-emitting diode reflection topography in healthy eyes.

To evaluate the intrasession repeatability of anterior corneal topographic and aberrometric measurements provided by a color-LED topographer as well as their interchangeability with those provided by a Scheimpflug-based system in healthy eyes. Thirty-five healthy eyes of 35 patients (age, 16-66years) were enrolled. A complete eye examination was performed in all cases including a complete corneal analysis with the Scheimpflug-based system Pentacam (Oculus Optikgeräte) (one measurement) and the Cassini system (i-Optics) (three consecutive measurements). Intrasession repeatability of the Cassini measurements was assessed with the within-subject standard deviation (Sw) and the intraclass correlation coefficient (ICC). The Bland-Altman analysis was used to evaluate the agreement between both devices. Mean Sw for keratometric readings was 0.02mm (ICC ≥ 0.992), ranging between 0.16 and 0.05D (ICC 0.930-0.978) for anterior and total astigmatic measurements. Mean Sw for asphericity and corneal diameter were 0.06 (ICC 0.926) and 0.03mm (IC 0.997), respectively. Aberrometric parameters showed ICCs ≥ 0.816, except for Z42 (ICC 0.741) and Z44 (ICC 0.544). When comparing devices, statistically significant differences were found for most of topographic and aberrometric data (p ≤ 0.044). Likewise, ranges of agreement between devices were clinically relevant (keratometry > 0.06mm; total astigmatic components > 0.69D; asphericity 0.35; second-, third-, and fourth-order Zernike terms, more than 0.20, 0.13, and 0.01μm, respectively). Consistent anterior corneal topographic, total corneal astigmatic, and aberrometric measurements are obtained with color-LED topography in healthy eyes, which are not interchangeable with those provided by the Scheimpflug-based topography.

Landing on the surface of Ryugu

Asteroids In October 2018, the Hayabusa2 spacecraft dropped the Mobile Asteroid Surface Scout (MASCOT) lander onto the surface of the asteroid (162173) Ryugu. Jaumann et al. analyzed images taken by the MASCOT camera during its descent and when resting on the surface. Colored light-emitting diodes were used to illuminate the lander's surroundings at night and produce color images. Ryugu's surface is dominated by two types of rock, but there is no evidence for fine-grained dust. Millimeter-sized inclusions in the rocks are similar to those present in carbonaceous chondrite meteorites. MASCOT operated for 17 hours on the surface before its nonrechargeable batteries ran out. Science , this issue p. [817][1] [1]: /lookup/doi/10.1126/science.aaw8627

Images from the surface of asteroid Ryugu show rocks similar to carbonaceous chondrite meteorites.

The near-Earth asteroid (162173) Ryugu is a 900-m-diameter dark object expected to contain primordial material from the solar nebula. The Mobile Asteroid Surface Scout (MASCOT) landed on Ryugu's surface on 3 October 2018. We present images from the MASCOT camera (MASCam) taken during the descent and while on the surface. The surface is covered by decimeter- to meter-sized rocks, with no deposits of fine-grained material. Rocks appear either bright, with smooth faces and sharp edges, or dark, with a cauliflower-like, crumbly surface. Close-up images of a rock of the latter type reveal a dark matrix with small, bright, spectrally different inclusions, implying that it did not experience extensive aqueous alteration. The inclusions appear similar to those in carbonaceous chondrite meteorites.

Validation of posterior corneal curvature measurements with color light-emitting diode topography.

To evaluate the intrasession repeatability and validity of posterior corneal curvature and astigmatism measurements provided by a color light-emitting diode reflection topography system in healthy eyes. A total of 40 healthy eyes of 40 patients (age, 16-66 years) were enrolled. A complete eye examination was performed in all cases including posterior topographic analysis with two systems: the Scheimpflug-based system (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany) and the Cassini system (i-Optics; Ophthec, The Hague, The Netherlands). With this last system, three consecutive measurements were taken to assess the level of intrasession repeatability (within-subject standard deviation, Sw; intraclass correlation coefficient). The Bland & Altman analysis was used to evaluate the interchangeability of both devices. The Sw was ⩽0.06 mm for all posterior corneal radius measurements, with intraclass correlation coefficient of ⩾0.960. The Sw for the magnitude of astigmatism, J0, and J45 were 0.15, 0.04, and 0.04 D, respectively, with intraclass correlation coefficient values of 0.876, 0.897, and 0.840, respectively. Statistically significant differences between devices were found in all parameters evaluated (p ⩽ 0.025). The interchangeability analysis revealed the presence of clinically relevant limits of agreement for the flattest (0.03 to 0.50 mm) and steepest posterior corneal radii (-0.01 to 0.39 mm). In contrast, limits of agreements were not clinically relevant for the magnitude of posterior astigmatism (-0.17 to 0.27 D) and their power vector components (-0.11 to 0.15 D). The Cassini system provides consistent measures of posterior corneal curvature and astigmatism in healthy eyes, but only measures of posterior astigmatism can be considered as interchangeable with those provided by the Pentacam.

Impact of solvents on energy gap, photophysical, photometric properties for a new class of 4-HCM coumarin derivative: Nonlinear optical studies and optoelectronic applications

Now a day the derivatives of biscoumarins are receiving overwhelming importance due to their application in designing organic semiconductor materials for display application. Therefore, a new photostable, light emitting and highly efficient synthesized material to exhibit display property and nonlinear optical active materials with good band gap energy, we have synthesized 4-Hydroxy-3-[(4-hydroxy-2-oxo-2H-chromen-3-yl)(4-methoxyphenyl)methyl]-2H-chromen-2-one (4-HCM) molecule via the simple catalytic method. The photophysical property of studied molecule in various organic solvents having different polarity exhibited considerably acceptable results. The results of quantum yield, lifetime and large Stoke shift shows the compound is a good promising candidate for the laser dyes and light emitting diode color filters. The energy band gap was determined by both experimentally and theoretically which is found to be an average of 3.78 eV which is well matched to the semiconducting materials band gap. The nonlinear optical absorption properties of the synthesized 4-HCM molecule are investigated using Z-scan technique. Further, the optoelectronic properties were investigated the CIE, color rendering index, color purity and color correlated temperature results of the 4-HCM in all studied solvents revels that this compound exhibits blue color (CIE-co-ordinates x = 0.14, y = 0.08) and is suitable for optoelectronic device applications.

Synthesis, photophysical, quantum chemical investigation, linear and non-linear optical properties of coumarin derivative: Optoelectronic and optical limiting application.

In order to develop a new photostable, light emitting and highly efficient synthesized material to exhibit display property and non-linear optical active materials with good band gap energy, we have synthesized molecule via simple catalytic method. The photophysical property of studied molecule in various organic solvents having different polarity exhibited considerably acceptable results. The results of quantum yield, lifetime and large Stoke shift shows the compound is a good promising candidate for the laser dyes and light emitting diode color filters. The energy band gap was determined by both experimentally and theoretically which is found to be an average of 3.2 eV which is well matched to the semiconducting materials band gap. The non-linear optical absorption properties of the synthesized molecule are dissolved in suitable solvents had been investigated using Z-scan technique. We have determined the sign and magnitude of nonlinear absorption coefficient by the method of open aperture Z-scan setup using an Nd: YAG continuous wave laser at 532 nm. The open aperture Z-scan profiles clearly demonstrate the presence of reverse saturable absorption kind nonlinearity in the investigated compound and are due to the two-photon absorption. Results of the non-linear optical studies confirm that the studied compound is more latent applications for optical limiting in continuous wave regime. Further, the optoelectronic properties were investigated the international commission on illumination, color rendering index, color purity, and correlated color temperature is results of the studied molecule in all studied solvents revels that this compound exhibits blue to cyan color and is suitable for organic light emitting diode which can be preferably used for daylight applications.

Comparison of keratometric measurements between color light-emitting diode topography and Scheimpflug camera

BackgroundTo determine the agreement of measurements between color light-emitting diode corneal topography (Cassini) and Scheimpflug camera keratometry (Pentacam HR).MethodsThe current retrospective study investigated 117 right eyes of 117 healthy patients before cataract surgery from June 2017 to July 2017. Steep K, flat K, mean K, astigmatism, and axis for both anterior and posterior corneal surface were measured using the two devices. The measured values were converted into J vectors such as J0 and J45. The mean difference for those measurement values were compared between the two instruments, and the agreement was evaluated using the Bland-Altman plot I.ResultsThere were statistically significant differences in mean K (44.21D [43.34 to 45.34] and 44.30D [43.30 to 45.10] by Cassini and Pentacam [P = 0.004]) and astigmatism (0.90D [0.58 to 1.30] and 0.70D [0.40 to 1.30] by Cassini and Pentacam [P = 0.002]) on the anterior corneal surface and flat K (− 6.21D [− 6.39 to − 6.07] and − 6.30D [− 6.5 to − 6.10] by Cassini and Pentacam [P < 0.001]), mean K (− 6.39D [− 6.54 to − 6.25] and − 6.40D [− 6.60 to − 6.30] by Cassini and Pentacam [P = 0.019]), and astigmatism (0.33D [0.22 to 0.47] and 0.30D [0.15 to 0.40] by Cassini and Pentacam [P = 0.002]) on the posterior corneal surface. The mean difference (= Cassini – Pentacam) with 95% limit of agreement for mean K and astigmatism of the anterior corneal surface were 0.082D (− 0.60 to 0.76) and 0.11D (− 0.73 to 0.95) for measurements obtained by the two instruments, respectively. Regarding keratometric values from the posterior corneal surface, the mean differences for flat K, mean K, and astigmatism were − 0.081D (− 0.42 to 0.26), − 0.030D (− 0.32 to 0.26), and 0.067D (− 0.33 to 0.46), respectively. Intraclass correlation coefficients for steep K, flat K, mean K, and vector J0 were higher than 0.9 in the anterior cornea. Positive correlation in steep K, flat K, mean K, astigmatism, and J0 was found between two devices in both anterior and posterior cornea (P < 0.001).ConclusionsCorneal refractive power and astigmatism tend to be higher when measured using Cassini than Pentacam HR in both anterior and posterior cornea. The two different devices might not be used interchangeably.Trial registrationRetrospectively registered. Registration number: KC17RESI0439.

Highly efficient full color light-emitting diodes based on quantum dots surface passivation engineering

High-efficiency quantum dots light-emitting diodes have been showing promise in the development of optoelectronic devices in displays and solid-state lighting. However, quantum dots surface traps strongly quench its luminescence when transfer it from in solution into on film. We propose a reproducible method of studying photoluminescence decay dynamics in nanocrystals by implementing surface passivation engineering, the results reveal that quantum dots surface traps-being the main cause of the fluorescence quenching and non-radiative recombination-could be eliminated by a series of surface post-treatment processes. Moreover, we study the quantum dots transient fluorescence spectra that the PL decay channel turned from the double exponential decay (control) to the mono-exponential decay kinetics (both the green and red quantum dots with UV-water co-treatment), and their quantum yields and stability are improved. Here we report all solution-processed multilayer monochromatic quantum dots light-emitting diodes what the emitting layer is formed from the surface post-treated red/green/blue quantum dots. These devices have exhibited a maximum current efficiency and external quantum efficiencies (EQE) of 20.7 cd/A and 14.4% for red, 65.1 cd/A and 15.9% for green, and 4.8 cd/A and 14.7% for blue devices, respectively. We expect the successful quantum dots surface passivation engineering would exert profound influence on their applications to light emitting devices.

Comparación de medidas de poder dióptrico corneal y astigmatismo entre un topógrafo basado en tecnología de diodo-emisor de luz a color (Cassini®) y un topógrafo basado en tecnología Scheimpflug (Pentacam®)

AimTo determine the agreement and to compare the measurements obtained from a colour light-emitting diode based (CassiniTM) and Scheimpflug (PentacamTM) based topography in the evaluation of the anterior, posterior, and total corneal power and astigmatism. MethodsA total of 30 eyes from 30 healthy patients were consecutively measured using PentacamTM and CassiniTM. The main evaluated parameters were the anterior, posterior, and total dioptric power, and a power vector analysis of the astigmatism. The agreement between both devices was analysed using the intraclass correlation coefficient (ICC) and performing Bland-Altman plots. The comparison of means was performed using paired Student t-test. ResultsThe agreement between both devices when comparing the anterior and total corneal dioptric power was very high (ICC>0.85), but not when studying the posterior cornea (ICC<0.5). In the astigmatism analysis, measurements from the anterior cornea also showed an excellent agreement (ICC>0.78), but was poor for the corneal posterior surface (ICC<0.31). When studying the corneal dioptric power, no statistically significant differences were found for the anterior surface (P>.05), but PentacamTM obtained higher values for posterior and total surfaces (P<.001). As regards the magnitude of the astigmatism, no significant differences were found between both devices. ConclusionBoth devices were highly comparable when studying the anterior cornea, but the agreement was poor-moderate when measuring posterior cornea. Therefore, the data obtained by both topographers are not interchangeable.

LED Illumination and Color Appearance of White-Balanced Images

ABSTRACTRecent studies revealed the failure of typical blue-pumped white light emitting diodes (LEDs) in rendering the white appearance of surface colors, which was caused by the lack of ultraviolet (UV)/violet radiation to excite the fluorescent whitening agents (FWAs). The effect of such a failure on image color appearance has not been previously investigated, though white surfaces are important in image white balance. In this study, two 6500 K sources—one containing a normal level of UV/violet radiation to simulate CIE standard D65 and the other containing a low level of UV/violet radiation to simulate typical blue-pumped white LEDs—were created to illuminate a Macbeth ColorChecker and three whiteness standards containing different amounts of FWAs. The scene was captured and white balanced using nine different algorithms. Though the two sources caused small color differences to the ColorChecker, both physically (ΔE*ab = 1.44) and in the unbalanced images (ΔE*ab = 2.53), the source with a low level of UV/violet radiation caused noticeable color shifts to the ColorChecker in the white-balanced images regardless of the algorithms. Furthermore, the chromaticities of the three whiteness standards were all shifted toward the origin in the a*–b* plane under the source with a low level of UV/violet radiation in the white-balanced images regardless of the algorithms, making them appear more similar to each other. Overall, the findings suggested the great impact of typical blue-pumped white LEDs on image color appearance.

Light emitting diodes applied in Synechococcus nidulans cultures: Effect on growth, pigments production and lipid profiles

Researches about light emitting diodes (LEDs) as energy source in microalgae cultivations has been growing in recent years due to its spectral quality, durability and reduced energy consumption. In this study, green, red and yellow LEDs were evaluated as energy source in Synechococcus nidulans LEB 115 cultures. Productivities and specific growth rates were up to 2.5 times greater than in cultures using fluorescent light. The different LED colors evaluated did not influence the chlorophyll, carotenoid or lipid productions. Biomass cultivated with LEDs showed high amounts of saturated fatty acids (above 48%), which is desirable for biodiesel production. In addition to the Synechococcus nidulans LEB 115 growth stimulation, the application of green, red and yellow LEDs in the cultivations produces potential biomass for biodiesel synthesis and other industrial interest biomolecules utilization.

Spectrally Resolved Fundus Autofluorescence in ABCA4-Related Retinopathy.

To investigate the green and red fluorescence emission component of hyperautofluorescent flecks in patients with ABCA4-related retinopathy. A confocal light-emitting diode (LED)-based retinal imaging system (EIDON) was used for image acquisition of patients with genetically confirmed ABCA4 mutations. Using 450-nm excitation wavelengths, spectrally resolved retinal autofluorescence images were acquired in two wavelength ranges: green emission fluorescent component (GEFC, 500-560 nm), and red emission fluorescent component (REFC, 560-700 nm). Image analysis included comparison of the two emission spectra, correlation with confocal EIDON LED color fundus images, and spectral-domain optical coherence tomography (OCT). Eighty eyes of 40 patients with ABCA4-related retinopathy were examined. A characteristic distribution of flecks with distinct pattern of fluorescence emission components was detected and quantified. Independent from disease manifestation, different proportions of GEFC and REFC were identified within single flecks. Centrally located flecks showed a higher proportion of GEFC and were characterized by local disruption of outer retinal bands in OCT. More peripheral flecks were more prominent in the REFC and correlated to subretinal hyperreflective deposits with only minor pathologic alterations of outer retinal layers. Individual flecks even showed spatial differences of the predominant fluorescent component. Spectrally resolved fundus autofluorescence intensity images feature characteristic distribution of GEFC and REFC in flecks, highlighting the heterogeneity of fluorophore distribution and providing more insight into the pathogenesis of ABCA4-related retinopathy. In view of upcoming therapeutic trials, longitudinal analysis of fluorescent components might facilitate monitoring of subtle disease progression and/or treatment effects.

Temperature-controlled spectral tuning of full-color carbon dots and their strongly fluorescent solid-state polymer composites for light-emitting diodes.

The development of full-color/white carbon-dot-based light-emitting diodes (LEDs) has been achieved, which show promising applications in full-color and flexible displays, backlights, and novel lighting sources. The gram-level synthesis of these full-color carbon dots (CDs) from citric acid by controlling the temperature has been achieved. By increasing the temperature from 120 to 180 °C, two, four, and six light-emitting CDs can be obtained, for which the emission wavelength shifts from 440 to 585 nm. This result reveals that temperature has a huge impact on the evolution of surface states, that is, increasing the temperature brings about enhanced surface functionalization and passivation, resulting in a red shift of the emission wavelength and enhancement of quantum yield. Then, full-color CDs/polymer composite phosphors are fabricated for efficient phosphor-based LED devices with quench-resistant solid-state fluorescence. By regulating the proportion of various CDs/polymer phosphors, white LEDs are realized with Commission Internationale de L'Eclairage coordinates of (0.32, 0.33) and a color rendering index of 82.7. The as-prepared CD-based full/white color LEDs can prove to be promising candidates for alternative light sources.

Layer pullet preferences for light colors of light-emitting diodes

Light colors may affect poultry behaviors, well-being and performance. However, preferences of layer pullets for light colors are not fully understood. This study was conducted to investigate the pullet preferences for four light-emitting diode colors, including white, red, green and blue, in a lighting preference test system. The system contained four identical compartments each provided with a respective light color. The pullets were able to move freely between the adjacent compartments. A total of three groups of 20 Chinese domestic Jingfen layer pullets (54 to 82 days of age) were used for the test. Pullet behaviors were continuously recorded and summarized for each light color/compartment into daily time spent (DTS), daily percentage of time spent (DPTS), daily times of visit (DTV), duration per visit, daily feed intake (DFI), daily feeding time (DFT), feeding rate (FR), distribution of pullet occupancy and hourly time spent. The results showed that the DTS (h/pullet·per day) were 3.9±0.4 under white, 1.4±0.3 under red, 2.2±0.3 under green and 4.5±0.4 under blue light, respectively. The DTS corresponded to 11.7% to 37.6% DPTS in 12-h lighting periods. The DTV (times/pullet·per day) were 84±5 under white, 48±10 under red, 88±10 under green and 94±8 under blue light. Each visit lasted 1.5 to 3.2 min. The DFI (g/pullet·per day) were 27.6±1.7 under white, 7.1±1.6 under red, 15.1±1.1 under green and 23.1±2.0 under blue light. The DFT was 0.18 to 0.65 h/pullet·per day and the FR was 0.57 to 0.75 g/min. For most of the time during the lighting periods, six to 10 birds stayed under white, and one to five birds stayed under red, green and blue light. Pullets preferred to stay under blue light when the light was on and under white light 4 h before the light off. Overall, pullets preferred blue light the most and red light the least. These findings substantiate the preferences of layer pullets for light colors, providing insights for use in the management of light-emitting diode colors to meet pullet needs.

Анализ цветовых характеристик источников света на базе светоизлучающих диодов в системах динамичного освещения

Lighting equipment manufacturers provide the following data that determine the lighting quality: the color temperature (CT), the general color rendering index and the ripple coefficient. However, for a lighting system to be designed in a professional manner, it is necessary to know such parameters as variation of the radiation spectral distribution in the course of operation, the repeatability of characteristics and the influence of environmental conditions on the light device as a whole. All these parameters and characteristics will allow the designer to take into account the specific features of the facility that has to be illuminated. New technologies and new light sources give an impetus for revising the existing lighting standards and rules. Light-emitting diodes (LEDs) are a relatively new, promising and energy-efficient light source, which has a number of unique properties: a long service life, high luminous efficiency, a high color rendering index, aesthetics, environmental friendliness, reliability, high strength and the possibility to control both spectral and integral parameters and characteristics. Owing to the compact size of LEDs, it became possible to make luminaires of various shapes and sizes, and, as a result, of different power and luminous flux. The existing values of luminous efficacy and improvement of the color LED selection (binning) method allow one to speak about the possibility to make a white light source based on color crystals. The use of LED-based light sources in dynamic lighting installations are of great interest for studying them because such light sources open the possibility of dimming the luminous flux and changing the radiation chromaticity independently of each other. Methods of making white LED modules with a variable color temperature (CT) on the basis of two-crystal luminiferous LEDs with different CT and multicrystal LEDs are considered. The accomplished analysis of the data obtained as a result of calculations made it possible to select suitable combinations of LEDs ensuring the best values of the color rendering index and CT repeatability.

Comparison of Corneal Astigmatism and Higher-order Aberrations between Color Light-emitting Diode Topographer and Scheimpflug Imager

Comparison of Corneal Astigmatism and Higher-order Aberrations between Color Light-emitting Diode Topographer and Scheimpflug Imager

Promotive Effect of MWCNT on ZnCo2O4 Hexagonal Plates and Their Application in Aqueous Asymmetric Supercapacitor

ZnCo2O4 (ZCO) hexagonal nanoplates were synthesized by a facile, robust and cost-effective co-precipitation method. The as-synthesized nanoplates were utilized as an electrode material and their electrochemical properties were investigated in three-electrode and two-electrode configurations with aqueous electrolyte of 1 M KOH. The fabricated ZCO electrode materials exhibited a specific capacity of 37 mAh g−1 at 1 A g−1. The capacity of the pristine ZCO nanoplates was further improved by incorporating multiwall carbon nanotubes (MWCNTs). The MWCNT@ZCO showed a specific capacity of 64 mAh g−1 at 1 A g−1. To examine practical performances, asymmetric supercapacitor (ASC) was also fabricated using MWCNT@ZCO as a positive electrode and activated carbon as a negative electrode. The specific capacity of the ASC was found to be 17 mAh g−1 at 0.38 A g−1. ASC could store sufficient energy to power a parallel combination of two red color light-emitting diodes. These findings may open new opportunities for the design of effective, stable, and easily recyclable ZCO electrode material for energy storage devices.