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Cu-Doped ZnO Electronic Structure and Optical Properties Studied by First-Principles Calculations and Experiments
摘要： The band structure, the density of states and optical absorption properties of Cu-doped ZnO were studied by the ?rst-principles generalized gradient approximation plane-wave pseudopotential method based on density functional theory. For the Zn1-xCuxO (x = 0, x = 0.0278, x = 0.0417) original structure, geometric optimization and energy calculations were performed and compared with experimental results. With increasing Cu concentration, the band gap of the Zn1-xCuxO decreased due to the shift of the conduction band. Since the impurity level was introduced after Cu doping, the conduction band was moved downwards. Additionally, it was shown that the insertion of a Cu atom leads to a red shift of the optical absorption edge, which was consistent with the experimental results.
关键词： absorption spectrum,electronic structure,?rst-principles calculations,Cu doped ZnO
更新于2025-09-23 15:22:29
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Photocatalytic Degradation of Aflatoxin B1 by activated carbon supported TiO2 catalyst
摘要： The photocatalytic efficiency of activated carbon supported TiO2 catalyst (AC/TiO2) for degradation of aflatoxin B1 (AFB1) under UV-Vis light was evaluated in this study. AC/TiO2 was prepared by simple hydrothermal synthesis and characterized by scanning electron micrograph (SEM), X-ray diffraction (XRD) and FT-IR. The various factors including catalyst dosage, pH value and light source affecting the degradation efficiency of AFB1 were also investigated. The higher degradation efficiency of AFB1 by AC/TiO2 composite (98 %) than bare TiO2 (76 %) were attributed to a higher surface area and enhanced visible light intensity by the synergy of AC and TiO2. The degradation process of AFB1 was fitted with the pseudo-first-order kinetic model. In addition, the catalyst can be easily separated from the solution and keep good activity. The hole (h+) and the hydroxyl radicals (?OH) were found to play an important role in the degradation of AFB1. These results demonstrated that AC/TiO2 possess synergy of high absorption capacity and photoactivity, thus supplying a simple, efficient and green approach for the degradation of AFB1.
关键词： AC/TiO2 catalyst,Photocatalytic Degradation,Aflatoxin B1
更新于2025-09-23 15:22:29
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Ultraviolet response of reduced graphene oxide/natural cellulose yarns with high flexibility
摘要： We prepared graphene yarn comprising reduced graphene oxide flakes and natural cellulose yarn by simple dip-coating and chemical reduction, and characterized its ultraviolet (UV) response under bending deformation. The as-prepared reduced graphene oxide cellulose yarns showed good basic properties including electrical conductivity (~1.0 S/cm) and mechanical stability (1,000 cycles), as well as a UV photoresponsivity of 1.31 mA/W (flat) and 1.0 mA/W (bent) and response times of 5 s/6 s (flat) and 6 s/7 s (bent). Our approach provides a path to realizing enhanced functional capabilities in natural cellulose textiles and their use in advanced smart textiles and wearable electronic/optoelectronic applications.
关键词： Flexibility,UV irradiation,Natural cellulose yarn,Reduced graphene oxide
更新于2025-09-23 15:22:29
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Raman spectroscopic analysis of testicular lamina propria predicts spermatogenesis in a mouse infertility model
摘要： The status of the testicular lamina propria (LP) is associated with spermatogenesis. The aim of this study was to determine whether Raman spectroscopy (RS) could detect material components within the LP and predict spermatogenesis. Twenty adult male mice were divided into a busulfan-treated group (n ? 16 mice receiving a single injection of 50 mg kg(cid:2)1, i.p., busulfan) and a control group (n ? 4 mice receiving an equivalent volume of 0.9% saline solution injected i.p.). Mice were killed 2, 4, 6 and 8 weeks after injection of busulfan or saline solution (n ? 1 control and 4 busulfan-treated mice at each time point). The testicular tubules were assessed by RS and compared with histopathological observations. Control tubules had raw spectral intensities below 2000 arbitrary units, whereas busulfan tubules had strengthened intensities that peaked at Week 4 (absent spermatogenesis) and returned to normal levels at Week 8 (restored spermatogenesis). The change in the LP revealed by RS occurred before the change in spermatogenesis detected by histopathology. Correspondingly, the sensitivity/specificity of RS for distinguishing busulfan-treated and control tubules at 2, 4, 6 and 8 weeks were 65.00%/70.00%, 95.00%/100.00%, 40.00%/100.00% and 25.00%/95.00% respectively. Collectively, RS could be used to evaluate the status of the LP and as a complement to histopathological evaluation to predict tubules with the potential to develop spermatogenesis for infertile patients.
关键词： spermatogenesis,busulfan,mouse infertility model,testicular lamina propria,Raman spectroscopy
更新于2025-09-23 15:22:29
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Nepafenac-Loaded Cyclodextrin/Polymer Nanoaggregates: A New Approach to Eye Drop Formulation
摘要： The topical administration route is commonly used for targeting therapeutics to the eye; however, improving the bioavailability of drugs applied directly to the eye remains a challenge. Different strategies have been studied to address this challenge. One of them is the use of aggregates that are formed easily by self-assembly of cyclodextrin (CD)/drug complexes in aqueous solution. The aim of this study was to design a new eye drop formulation based on aggregates formed between CD/drug complexes. For this purpose, the physicochemical properties of the aggregates associated with six CDs and selected water-soluble polymers were analysed. Complex formation was studied using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance spectroscopy (1H-NMR). Results showed that HPβCD performed best in terms of solubilization, while γCD performed best in terms of enhancing nanoaggregate formation. Formation of inclusion complexes was con?rmed by DSC, FT-IR and 1H-NMR studies. A mixture of 15% (w/v) γCD and 8% (w/v) HPβCD was selected for formulation studies. It was concluded that formulations with aggregate sizes less than 1 μm and viscosity around 10–19 centipoises can be easily prepared using a mixture of CDs. Formulations containing polymeric drug/CD nanoaggregates represent an interesting strategy for enhanced topical delivery of nepafenac.
关键词： cyclodextrin,self-assemble,nepafenac,aggregate,polymer,complexation,ocular drug delivery
更新于2025-09-23 15:22:29
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Over-Stretching Tolerant Conductors on Rubber Films by Inkjet-Printing Silver Nanoparticles for Wearables
摘要： The necessity to place sensors far away from the processing unit in smart clothes or artificial skins for robots may require conductive wirings on stretchable materials at very low-cost. In this work, we present an easy method to produce wires using only commercially available materials. A consumer grade inkjet printer was used to print a wire of silver nanoparticles with a sheet resistance below 1 Ω/sq. on a non-pre-strained sheet of elastic silicone. This wire was stretched more than 10,000 times and was still conductive afterwards. The viscoelastic behavior of the substrate results in a temporarily increased resistance that decreases to almost the original value. After over-stretching, the wire is conductive within less than a second. We analyze the swelling of the silicone due to the ink’s solvent and the nanoparticle film on top by microscope and SEM images. Finally, a 60 mm long stretchable conductor was integrated onto wearables, and showed that it can bear strains of up to 300% and recover to a conductivity that allows the operation of an assembled LED assembled at only 1.8 V. These self-healing wires can serve as wiring and binary strain or pressure sensors in sportswear, compression underwear, and in robotic applications.
关键词： silver nanoparticles,stretchable,printed electronics,wearables,inkjet printing
更新于2025-09-23 15:22:29
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Planar Antiaromatic Core-Modified 24π Hexaphyrin(1.0.1.0.1.0) and 32π Octaphyrin(1.0.1.0.1.0.1.0) Bearing Alternate Hybrid-Diheterole Units
摘要： Lewis acid catalyzed self-condensation of hybrid diheterole (furan-pyrrole and thiophene-pyrrole) precursors afforded novel Hückel antiaromatic 24π hexaphyrin(1.0.1.0.1.0) and 32π octaphyrin(1.0.1.0.1.0.1.0) without β-annulated bridges. Single-crystal X-ray diffraction analysis of the hybrid porphyrinoids (S3N3-ox and O4N4-ox) revealed nearly planar conformation and the 1H NMR spectra suggested the presence of paratropic ring currents. These antiaromatic macrocycles showed the characteristic optical features and undergo reversible two-electron reduction to Hückel aromatic 26π- and 34π-electron species, respectively, as is evident from the spectroscopic and theoretical studies (NICS and ACID calculations). Implementation of hybrid diheteroles alternately into the expanded porphyrin skeletons would be a novel approach for fine-tuning of the electronic structures of the planar antiaromatic macrocycles.
关键词： cyclization,antiaromaticity,conformation,redox,porphyrinoids
更新于2025-09-23 15:22:29
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Site Occupancy Studies and Luminescence Properties of Emission Tunable Phosphors Ca <sub/>9</sub> La(PO <sub/>4</sub> ) <sub/>7</sub> :Re (Re = Ce <sup>3+</sup> , Eu <sup>2+</sup> )
摘要： The structure, site occupancies, and photoluminescence (PL) properties of Ce3+- or Eu2+-doped Ca9La(PO4)7 phosphors were investigated in this work. The powder X-ray diffraction (XRD) data and Rietveld refinement results showed that the phosphors are pure phases. The vacuum ultraviolet-ultraviolet?visible (VUV-UV?vis) spectra and decay curves confirmed that the Ce3+ and Eu2+ ions in Ca9La(PO4)7 occupied two crystal sites. Additionally, the tunable color can be obtained by adjusting doping concentration and altering temperature. The fabricated w-LED lamp based on Eu2+-doped Ca9La(PO4)7 phosphor gave properties with a color rendering index (CRI) of 85.26, CIE chromaticity coordinates of (0.358, 0.307), and color temperature (CCT) of 4329 K.
更新于2025-09-23 15:22:29
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Soluble and insoluble polymer-inorganic systems based on poly(methyl methacrylate), modified with ZrO2-LnO1.5 (Ln = Eu, Tb) nanoparticles: Comparison of their photoluminescence
摘要： The study of the lanthanide ion luminescence as a function of their environment in polymer-inorganic composites is necessary for better understanding of the electron energy transfer processes in a condensed state. From a practical point of view, these materials are promising for optics and medicine. The nanoparticles of ZrO2-LnO1.5 (Ln = Eu, Tb) solid solutions were synthesized by hydrothermal method. The surface functionalization of the obtained nanoparticles by vinyl groups was carried out using 3-(trimethoxysilyl)propyl methacrylate. Soluble and cross-linked composites based on poly(methyl methacrylate) with ZrO2-LnO1.5 nanoparticles were synthesized using radical polymerization in solution and bulk. Molecular weight, thermal stability, and microhardness of the obtained composite materials were determined. The influence of both the polymerization conditions and the forming composite structure on the lanthanide ion photoluminescence in ZrO2 nanoparticles covalently bonded to the polymer matrix was studied. The combination of ZrO2-EuO1.5 and ZrO2-TbO1.5 nanoparticles in the poly(methyl methacrylate) resulted in the production of composites with photoluminescence spectra overlapping the red and green regions of the visible range. It was shown that the structure of the composite affects the absorbing capacity of luminescent centers and allows shifting the excitation spectrum in the longer wavelength region.
关键词： hydrothermal synthesis,poly(methyl methacrylate),rare-earth ions,solid solutions,zirconia,hybrid nanomaterials
更新于2025-09-23 15:21:21
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[ASME ASME 2018 13th International Manufacturing Science and Engineering Conference - College Station, Texas, USA (Monday 18 June 2018)] Volume 1: Additive Manufacturing; Bio and Sustainable Manufacturing - High-Throughput 3D Printing of Customized Imaging Lenses
摘要： The emerging 3D printing technology has the potential to transform manufacturing customized optical elements, which currently heavily relies on the time-consuming and costly polishing and grinding processes. However, the inherent speed-accuracy trade-off seriously constraints the practical applications of 3D printing technology in optical realm. In addressing this issue, here, we report a new method featuring a significantly faster fabrication speed, at 24.54 mm3/h, without compromising the fabrication accuracy or surface finish required to 3D-print customized optical components. We demonstrated a high-speed 3D printing process with deep subwavelength (sub-10 nm) surface roughness by employing the projection micro-stereolithography process and the synergistic effects from the grayscale photopolymerization and the meniscus equilibrium post-curing methods. Fabricating a customized aspheric lens with 5 mm in height and 3 mm in diameter could be accomplished in less than four hours. The 3D-printed singlet aspheric lens demonstrated a maximal imaging resolution of 2.19 μm with low field distortion less than 0.13% across a 2-mm field of view. This work demonstrates the potential of 3D printing for rapid manufacturing of optical components.
关键词： optical lenses,meniscus equilibrium post-curing,projection micro-stereolithography,3D printing,grayscale photopolymerization
更新于2025-09-23 15:21:01