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Glass transition and crystallization of ZnO-B2O3-SiO2 glass doped with Y2O3
摘要： The effect of Y2O3 on the glass transition kinetics, crystallization kinetics, phase separation and crystallization behavior of 60ZnO–30B2O3–10SiO2 glass has been investigated by non-isothermal differential thermal analysis, scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The glass transition activation energies Eg calculated by using both Kissinger and Moynihan model decrease from 668 kJ/mol to 573 kJ/mol for Kissinger model, and 682 kJ/mol to 587 kJ/mol for Moynihan model with the increase of yttrium oxide doping content from 0 to 6 mol%. And the glass crystallization kinetics parameters, crystallization activation energy Ec and Avrami exponent n stands for crystal growth, are also obtained on the basis of several well developed equations. Increase of about 58 kJ/mol in Ec values obtained by different theoretical equations is caused by addition of 6 mol% yttrium oxide into 60ZnO–30B2O3–10SiO2 glass, and the Avrami exponent (n close to 2) suggests that crystal growth in 60ZnO–30B2O3–10SiO2 glass doped with or without yttrium is mainly one-dimensional growth of crystals. The results on the phase separation and crystallization behavior occurred at 893 K and 993 K respectively for base and doped glass, are well consistent with the glass transition and crystallization kinetics results. Hence, addition of yttrium oxide into 60ZnO–30B2O3–10SiO2 glass decrease the glass transition activation energy while increase the crystallization activation energy of glass, thereby the stability of glass structure is improved. Phase separation phenomenon and crystallization behavior occurred at glass surface provide some useful information for preparing glass ceramics with micro- or nano-crystals in surface.
关键词： Thermal properties,Y2O3,Electron microscopy,Glass
更新于2025-09-23 15:22:29
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Image and data processing algorithms for identifying cell-bound membrane vesicle trajectories and movement information
摘要： This DIB article provides details about the trajectory identification and data processing algorithms used in the article "Dynamic single-vesicle tracking of cell-bound membrane vesicles on resting, activated, and cytoskeleton-disrupted cells" (Zhang et al.) [1]. The algorithm identifies vesicles on cell membranes from series of undyed grayscale images captured by the confocal microscope based on contrast differences and then trajectories of vesicles are obtained by analyzing their positions in consecutive images. Once the trajectories have been obtained, other quantitative movement information, such as moving speed, direction and acceleration, are derived by standard dynamic relations.
关键词： MATLAB algorithms,Vesicle tracking,Trajectory tracing,Confocal microscopy,Image processing
更新于2025-09-23 15:22:29
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Structure and properties of layered perovskites Ba1-Ln Fe1-Co O3-δ (Ln = Pr, Sm, Gd)
摘要： A series of samples of overall composition Ba1-xLnxFe1-yCoyO3-δ (Ln = Pr, Sm, Gd) with x = 0.3-0.4; y = 0-0.5 were prepared by glycerin nitrate technique in air. The crystal structure of single-phase Ba1-xLnxFe1-yCoyO3-δ (Ln = Pr, Sm, Gd) determined by XRD was described as cubic (sp. gr. Pm3(cid:1)m). However, transmission electronic microscopy revealed that both Sm- and Gd-doped oxides possess tetragonal structure with 5-fold and 3-fold increased c parameter respectively. Oxygen content in the complex oxides has been determined in air over wide temperature range by means of thermogravimetry and iodometric titration. The change in oxygen content with temperature for the phases with five-layered ordering was significantly smaller than for the disordered phases.
关键词： oxygen nonstoichiometry,X-ray diffraction,oxide materials,transmission electron microscopy,crystal structure
更新于2025-09-23 15:22:29
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Fabrication of AlN templates on SiC substrates by sputtering-deposition and high-temperature annealing
摘要： High-quality AlN templates fabricated by sputtering-deposition and post-deposition high-temperature annealing have great potential for deep ultraviolet light-emitting device applications. In this work, we fabricated AlN films on 6H-SiC substrates by sputtering and face-to-face annealing and characterized the structural quality of the AlN films before and after annealing. As reported in previous studies, to accomplish high-quality AlN films on SiC substrates using conventional methods, such as molecular beam epitaxy or metalorganic vapor phase epitaxy (MOVPE), it is important to grow the AlN on the SiC coherently. However, in this work, although the annealed AlN films were fully relaxed from the SiC substrates, or even had tensile strain, the AlN films indicated high crystallinity. The X-ray rocking curve full width at half maximum (XRC-FWHM) values of the 200-nm-thick annealed AlN film were 17 and 246 arcsec for the AlN (0002) and (10–12) diffraction, respectively. Though the annealed AlN film indicated rough surfaces with bunched step structures, the surface morphology was remarkably improved by MOVPE growth and clear atomic step-and-terrace structures were formed. The XRC-FWHM values of the MOVPE-grown AlN were 90 and 239 arcsec for the AlN (0002) and (10–12) diffraction, respectively.
关键词： A1. Stresses,A1. Atomic force microscopy,B1. Nitrides,B2. Semiconducting III-V materials,A1. X-ray diffraction
更新于2025-09-23 15:22:29
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Tuning of carbon dots emission color for sensing of Fe3+ ion and bioimaging applications
摘要： Herein, we report a facile one-step synthetic strategy for fabrication of three (blue, green and yellow) fluorescent color carbon dots (CDs) from tomato (Solanum lycopersicum). The as-synthesized CDs showed emission peaks at 450, 520 and 560 nm for blue, green and yellow color CDs when excited at 370, 420 and 460 nm, respectively. Using tomato as a carbon source, the fabricated three fluorescent color CDs showed good water dispersity and high quantum yield. The analytical performances of three fluorescent color CDs are evaluated by detecting Fe3+ ion in biofluids and iron tablets. Upon the addition of Fe3+ ion under optimal conditions, the fluorescence intensity of three fluorescent color CDs was quenched linearly over the range of 0.1 to 2.0 μM. This method opens a new analytical strategy to quantify Fe3+ ion in iron tablets and biofluids with high sensitivity. Further, the uptake of three fluorescent color CDs into HeLa cells was confirmed by confocal laser scanning microscopy. Intracellular experiments demonstrated that the three fluorescent color CDs were effectively internalized the cells and show excellent biocompatibility and low toxicity, suggesting that the CDs can be used as good candidates for biomedical applications.
关键词： Fluorescent carbon dots,Fe3+ ion,Cancer cells,Fluorescence spectroscopy and microscopy,Tomato
更新于2025-09-23 15:22:29
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Metal nanowire–polymer matrix hybrid layer for triboelectric nanogenerator
摘要： In this work, we studied the surface potential of a metal–polymer hybrid layer and its effect on the performance of a triboelectric nanogenerator (TENG). Ag nanowires (AgNWs) separately embedded in two different polymers–one with a positive tribopotential and the other with a negative tribopotential–were prepared as model hybrid systems. The surface potentials of the hybrid system were systematically investigated by Kelvin probe force microscopy. The results demonstrated that each component of the hybrid layer affected the other component because of the difference in their work functions. The following two important findings were obtained. First, the surface potential of each polymer shifted drastically toward that of Ag and the surface potential of Ag shifted toward that of each polymer. Second, higher density of AgNWs led to higher Ag-induced charge density in the polymer, which consequently resulted in larger shift in the surface potential of the polymer. TENG performance measurements revealed that the tribopotential difference between the contact surfaces of the AgNW–polymer hybrid layer and the perfluoroalkoxy alkane (or Nylon) used as the top triboelectric layer governed the TENG performance. Our systematic investigation of the surface potential of a hybrid surface consisting of two materials with different surface potentials provides insight into the design of triboelectric layers for high-performance TENGs.
关键词： triboelectric nanogenerator,silver nanowire,kelvin probe force microscopy,hybrid,surface potential
更新于2025-09-23 15:22:29
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Quantitative imaging of membrane micropolarity in living cells and tissues by spectral phasors analysis
摘要： Intracellular micropolarity is essential in several metabolic processes, as it controls membrane permeability, fluxes of molecules and energy. Here we describe a method for the determination of the micropolarity in living cells using spectral confocal microscopy. The method is based on a phasor analysis of spectrally resolved images of live cells, labelled with the solvatochromic probe Nile Red. An application is provided to extract a polarity profile from the acquired Spectral datasets, which represent the contribution of hyperpolar, polar and non-polar lipids, and to generate a micropolarity map at submicrometric spatial resolution. A metabolic parameter, representing a quantitative index of the fatty acid-triacylglycerol turnover, is also furnished. This method allows a functional profiling of cells and tissues and the detection of metabolic imbalances between lipid storage and usage.
关键词： Membranes micropolarity,Nile Red,Fatty acids,Triglycerides,Lipid droplets,Confocal microscopy,Metabolic imaging,Spectral phasors,Lipids
更新于2025-09-23 15:22:29
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Effects of temporary fogging and defogging in plastic scintillators
摘要： Recent studies have shown that under certain environmental conditions, plastic scintillators which are used in a variety of applications in outdoor environments develop defects called "fogging", resulting in a reduced useful lifetime and increased maintenance cost. Applications of plastic scintillators include scanning recycled steel going into a processing plant, personnel portals to scan employees, and scanning cargo and cars crossing borders of many countries. In this report, fogging was studied in conventional PVT and PS-based plastic scintillators, both field aged and freshly cast. A new fogging-resistant PVT-based formulation developed by scientists at Lawrence Livermore National Laboratory (LLNL) was tested as well. We used accelerated aging experiments via temperature and humidity cycling in controlled laboratory conditions to create observable temporary fogging defects in small samples (≤1 in3). Photoluminescence and optical transmission studies were used to evaluate the effect of the fogging. The time evolution of the induced temporary fogging formation and defogging (i.e. fading of defects in ambient conditions over time) were recorded using optical microscopy, time-lapse photography, and gravimetric analysis.
关键词： Accelerated aging,Optical microscopy,Scintillator,Gamma detection
更新于2025-09-23 15:22:29
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Unusual Electronic States and Superconducting Proximity Effect of Bi Films Modulated by NbSe2 Substrate
摘要： Heterostructures of two-dimensional layered materials can be functionalized with exotic phenomena that are unpresented with each constituting component. The interface effect plays a key role in determining the electronic properties of the heterostructure, whose characterization requires a correlation with the morphology with atomic-scale precision. Here, we report an investigation on the electronic properties of few-layer Bi(110) films mediated by NbSe2 substrate. By utilizing scanning tunneling microscopy and spectroscopy, we show a significant variation of the density of states at different Bi film thicknesses, resulting in an unusual superconducting proximity effect that deviates from the conventional monotonous decay behavior. Moreover, the electronic states of the Bi films are also prominently modulated by the Moiré pattern spatially. With first-principles calculations, we illuminate these findings as the results of covalent-like quasi-bonds formed at the Bi/NbSe2 interface, which profoundly alter the charge distributions in the Bi films. Our study indicates a viable way of modulating the electronic properties of ultrathin films by quasi-covalent interfacial couplings beyond conventional van der Waals interactions.
关键词： few-layers bismuth(110),two-dimensional heterostructures,thickness dependence,scanning tunneling microscopy,density functional theory calculations,covalent-like quasi-bonds,proximity effect
更新于2025-09-23 15:22:29
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A comparison of the morphological and electrical properties of sol-gel dip coating and atomic layer deposition of ZnO on 3D nanospring mats
摘要： We report on the morphological and electrical properties, with (light) and without (dark) UV illumination, of conformal coatings of ZnO on silica nanosprings deposited by sol-gel and atomic layer deposition (ALD) for the first time. Field Emission Scanning Electron Microscopy (FESEM) imaging showed that both methods produce conformal coatings of ZnO on the nanosprings. The surface of the sol-gel coatings exhibited cracks at higher numbers of dipping/sintering cycles, while the morphology of ALD ZnO films were always smooth and devoid of cracks. The effective photoconductivity of the sol-gel ZnO coated nanospring mats increased nonlinearly with increasing coating thickness. The corresponding dark effective conductivity of the sol-gel ZnO coated nanospring mats also increased within the same thickness range. Alternatively, the effective photoconductivity of the ALD ZnO coated nanospring mats increased linearly with increasing coating thickness. The corresponding dark effective conductivity also increased within the same thickness range. The superior effective conductivity and photoconductivity of the ALD ZnO coated nanospring mats is attributed to the uniformity of the coating and the absence of cracks, which are observed for the thicker sol-gel ZnO coatings.
关键词： atomic layer deposition (ALD),semiconductors,sol-gel,nanosprings,field emission scanning electron microscopy,conductivity,ZnO
更新于2025-09-23 15:22:29