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Inactivation of airborne bacteria using different UV sources: Performance modeling, energy utilization, and endotoxin degradation
摘要： Airborne bacteria-containing bioaerosols have attracted increased research attention on account of their adverse effects on human health. Ultraviolet germicidal irradiation (UVGI) is an effective method to inactivate airborne microorganisms. The present study models and compares the inactivation performance of three UV sources in the UVGI for aerosolized Escherichia coli. Inactivation efficiency of 0.5, 2.2 and 3.1 logarithmic order was obtained at an exposure UV dose of 370 J/m3 under UVA (365 nm), UVC (254 nm) and UVD (185 nm) sources, respectively. A Beer–Lambert law-based model was developed and validated to compare the inactivation performances of the UV sources, and modeling enabled prediction of inactivation efficiency and analysis of the sensitivity of several parameters. Low influent E. coli concentrations and high UV doses resulted in high energy consumption (EC). The change in airborne endotoxin concentration during UV inactivation was analyzed, and UVC and UVA irradiation showed no marked effect on endotoxin degradation. By contrast, both free and bound endotoxins could be removed by UVD treatment, which is attributed to the ozone generated by the UVD source. The results of this study can provide a better understanding of the air disinfection and airborne endotoxin removal processes.
关键词： Energy utilization,Bioaerosol,Airborne endotoxin,UV germicidal irradiation (UVGI),Model
更新于2025-09-10 09:29:36
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Effect of gamma irradiation dose on the structure and pH sensitivity of ITO thin films in extended gate field effect transistor
摘要： Even though several studies have demonstrated the use of Indium Tin Oxides (ITO) as an extended gate field effect transistor (EGFET), the effect of different doses of gamma radiation on the intrinsic properties of the ITO films has not been considered. This study investigates the effect of gamma irradiation on the structural, optical, morphological and electrical properties as well as pH sensitivity (as an extended gate field effect transistor) of ITO thin films. ITO thin films with thickness of 400 nm were prepared using a radio frequency sputtering technique. The samples were then subjected to various doses of gamma radiation from a Co-60 radio-isotope (0.5 kGy, 1 kGy, 1.5 kGy, and 2 kGy). The structural and morphological changes as well as transmission and absorption of the thin films were analyzed using X-ray diffraction (XRD), Atomic Force Microscopy (AFM), Field-Emission Scanning Electron Microscope (FESEM) and UV-Vis spectrophotometry, before and after irradiation. The irradiated ITO thin films were then used as an extended gate field effect transistor to determine its ability to improve sensitivity as pH sensors. The grain size and transmittance in the range 300-900 nm of the ITO films were found to decrease with increasing gamma irradiation dose. In contrast, the uniformity and surface roughness of ITO thin films increased with increasing gamma radiation dose due to the formation of lattice defects. Moreover, the electrical resistance of the thin films increased with increasing dose because of the low current density and high number of surface defects associated with irradiation. The pH sensitivity of the ITO thin films improved after irradiation, possibly due to the concomitant increase in surface roughness with increasing radiation dose. The improvements in the pH sensitivity of ITO thin films after irradiation justify their potential use as pH sensors.
关键词： EGFET,pH sensor,Optical band gap,Gamma irradiation,X-ray diffraction,Indium Tin Oxide,Thin films
更新于2025-09-10 09:29:36
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Polymeric Microneedles Integrated with Metformin-Loaded and PDA/LA-Coated Hollow Mesoporous SiO2 for NIR-triggered Transdermal Delivery on Diabetic Rats
摘要： Herein, a NIR-responsive polymeric microneedles (MNs) system incorporated with metformin-loaded and polydopamine/lauric acid (PDA/LA)-coated hollow mesoporous SiO2 have been developed for transdermal delivery of antidiabetic drug (metformin). Firstly, an anti-diabetic drug was firstly loaded within hollow mesoporous SiO2 nanoparticles (HMSN) by a diffusion method. Then, PDA as photothermal conversion agent and lauric acid (LA) as phase change material (PCM) were coated onto the HMSN to form NIR-responsive drug nanocarriers. Finally, these metformin-Loaded and PDA/LA-coated HMSN were encapsulated into poly(vinylpyrrolidone) (PVP) MNs. After insertion into skin tissue, LA could be melt with the photothermal conversion of PDA under NIR-light, and thus enabling to release encapsulated metformin from MNs. The in vivo release behavior of metformin from MNs into skin was further studied to investigate its hypoglycemic effect on diabetic rats. Compared with the subcutaneous injection of metformin, the bioavailability of MNs-NIR groups was 95.8±2.7%. The antidiabetic drug can be precisely released by adjustment of exposure time and power densities of NIR-light.
关键词： NIR irradiation,microneedles,transdermal delivery,diabetes,hypoglycemic
更新于2025-09-10 09:29:36
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Architecture of Biperovskite-Based LaCrO <sub/>3</sub> /PbTiO <sub/>3</sub> p–n Heterojunction with a Strong Interface for Enhanced Charge Anti-recombination Process and Visible Light-Induced Photocatalytic Reactions
摘要： Erection of a resourceful p?n heterojunction is a state-of-the-art tactic to flourish the charge anti-recombination process at the heterojunction interface and boost the photocatalytic activities under visible light irradiation. In the present work, we have engineered a new series of PbTiO3/LaCrO3 (PT/LC) p?n heterojunction through a facile two-step combustion process. The structural, interface, and optical analysis distinctly revealed a strong intact between p-type LaCrO3 and n-type PbTiO3, elucidating their electronic channelization and substantial reduction of electron?hole recombination at the PbTiO3/LaCrO3 interface, which extend the lifetime and population of photogenerated charges in the p?n heterojunction material. The asymmetry photocurrent in the opposite directions and an inverted characteristic V-shape Mott?Schottky plot of the optimal PT/LC (7/3) material demonstrated the construction of a p?n heterojunction. The optimal p?n heterojunction possesses excellent photo-stability, and it revealed the highest photocatalytic activity toward degradation of phenol, that is, 86% and hydrogen generation, that is, 343.57 μmol in 2 h. The enhanced photocatalytic activities of the p?n heterojunction materials in comparison to pristine ones are due to the higher separation charge carriers across the p?n heterojunction interface, which was deeply elucidated by carrying out electrochemical impedance spectroscopy, time-resolved photoluminescence spectroscopy, and photoluminescence analyses. These materials pave a new way to design the interface intact photocatalyst with an ultrafast approach for migration of photoexcited electrons across the p?n heterojunction and enhance the photocatalytic activities.
关键词： p?n heterojunction,PbTiO3/LaCrO3,visible light irradiation,photocatalytic activities,charge anti-recombination
更新于2025-09-10 09:29:36
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Comparison of UV-Irradiation and Sintering on Mesoporous Sponge-like ZnO Films Prepared from PS-b-P4VP Templated Sol-Gel Synthesis
摘要： Mesoporous ZnO films with large surface-area-to-volume-ratio show great promise in multiple applications, among which solid-state dye-sensitized solar cells (ssDSSCs) have attracted great attention in the field of photovoltaics. An appropriate mesopore size in the nanostructured ZnO films significantly plays an indispensable role in improving the device efficiency resulted from an efficient penetration of dye molecules and solid hole transport material. In the present work, mesoporous sponge-like ZnO films are prepared using sol-gel synthesis templated by a diblock copolymer polystyrene-block-poly(4-vinylpyridine). Two different template removal techniques, UV-irradiation and high temperature sintering, are used to compare their respective impact on the pore sizes of the final ZnO thin films. Both, the surface morphology and the inner morphology show that mesopores obtained via UV-irradiation are smaller as compared to their sintered counterparts. Moreover, increasing the template-to-ZnO precursor ratio is found to further enlarge present mesopores. Accordingly, a strong correlation between the pore sizes of sol-gel synthesized ZnO films and photovoltaic performance of fabricated ssDSSCs is demonstrated. In contrast with the devices fabricated from the UV-irradiated ZnO films, those obtained from sintered samples show more than two times higher efficiency.
关键词： sintering,mesopores,grazing-incidence small-angle X-ray scattering,UV-irradiation,solid-state DSSCs
更新于2025-09-10 09:29:36
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Effect of the Gamma-Ray Irradiation on the Electric and Optical Properties of SrTiO3 Single Crystals
摘要： We investigated the visible emission property of SrTiO3 (STO) single crystals irradiated with gammy-ray (γ-ray) at various total doses up to 900 kGy. The electric and optical absorption properties of the irradiated STO samples were hardly changed with the γ-ray irradiation, compared with those of un-irradiated STO. In contrast, the visible emission near 550 nm increased with the γ-ray dose increasing. While the development of the visible emission was indicative of the increase of oxygen vacancies inside STO by the γ-ray irradiation, the newly generated oxygen vacancies were not significantly harmful to the electric and optical properties of STO. We concluded that the STO single crystal should have a good tolerance against the damage by the γ-ray irradiation.
关键词： Gamma-ray irradiation,Photoluminescence,Oxygen vacancy,SrTiO3 single crystal
更新于2025-09-10 09:29:36
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Effects of ultraviolet photon irradiation and subsequent thermal treatments on solution-processed amorphous indium gallium zinc oxide thin films
摘要： Effects of exposure to ultraviolet (UV) photons and thermal treatments on solution-processed amorphous indium gallium zinc oxide (a-IGZO) films were investigated by X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. As a result, oxygen vacancies obviously become more abundant in the films sintered at 250 or 300 ?C by the exposure to 7.21 eV photons and less abundant by the subsequent thermal treatment at 250 ?C in air. The drain current also clearly becomes smaller in a thin film transistor fabricated using the IGZO film in a manner opposite to the abundance of oxygen vacancies. That is, the drain current becomes smaller by the UV irradiation and returns to the original high value by the subsequent thermal treatment. This indicates that oxygen vacancies act as trapping centers or scattering centers of electrons. In addition, the reversible change of the drain current with the cycle of UV irradiation and the thermal treatment opens the possibility of the use of the IGZO films as a UV sensor.
关键词： oxygen vacancies,amorphous indium gallium zinc oxide,thin film transistor,UV irradiation,thermal treatment
更新于2025-09-10 09:29:36
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Total-ionizing-dose effects and proton-induced displacement damage on MoS2-interlayer-MoS2 tunneling junctions
摘要： Tunneling-dominated charge transport is demonstrated in vertically stacked MoS2/interlayer/MoS2 heterostructures with Al2O3, h-BN and HfO2 dielectrics. All devices are highly resistant to 10-keV X-ray irradiation. Only small transient changes in X-ray-induced photocurrent are observed as a result of trap creation in the thin interlayer dielectric, with rapid passivation. Samples with Al2O3 and h-BN interlayer dielectrics show significant increases in conduction current during proton irradiation, due to displacement-damage-induced defects that lower the effective tunnel-barrier height. Density-functional-theory calculations provide insights into the pertinent defects. Devices with HfO2 interlayer dielectrics show great promise for use in radiation-tolerant, ultimately-scaled tunnel FETs.
关键词： 2 dimension,HfO2,proton irradiation,X-ray,DFT,h-BN,MoS2 tunnel junction
更新于2025-09-09 09:28:46
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Decoration of SrTiO3 nanofibers by BiOI for photocatalytic methyl orange degradation under visible light irradiation
摘要： BiOI decorated electrospun SrTiO3 nanofibers (BE) with a spiky club structure were fabricated using a rapid microwave-assisted solvothermal method. The exposed (102) plane of BiOI preferentially coupled with the electrospun SrTiO3 fibers aiming to achieve charge neutrality. XRD analysis demonstrated that a BE composite coupled with an optimal content of BiOI exhibited few crystal imperfections. The resulting BE samples showed a higher degradation efficiency towards methyl orange dye under visible light irradiation (λ > 400 nm) compared to the individual BiOI and SrTiO3. The BE composite possessed a high degradation rate of 0.015 (kapp, min–1) and a normalized rate constant of 2.46 × 10–3 (kapp/surface area), which was 7.7 and 1120 times higher than those of BiOI and SrTiO3 alone, and a degradation level over 94.6% within 3 h of irradiation under visible light. The high photocatalytic activity could be attributed to the heterostructure formation, p-n junction at the BE interface, high contact between water and dye molecules with the BiOI covered surface, and extended visible light absorption. This work provides an effective approach to produce BE nanofibers for dealing with methyl orange dye and proves that BE composites have the potential to serve as visible-light-driven photocatalysts.
关键词： Visible light irradiation,Photocatalyst,SrTiO3,BiOI,Nanofiber
更新于2025-09-09 09:28:46
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Nanocrystalline ZnO doped lanthanide oxide: An efficient photocatalyst for the degradation of diesel pollutant in seawater under visible light irradiation
摘要： In this study, a ZnO doped Er2O3 photocatalyst is employed to degrade diesel pollutant in seawater under visible light irradiation. The photocatalyst was prepared by a precipitation method and was characterized by SEM and XRD analysis. The experimental results proved that the nanocrystalline photocatalysts were highly active in the visible region. The photocatalytic degradation efficiency of diesel was analysed by various experimental parameters namely dosage, doping ratio, initial concentration of diesel, pH value, concentration of H2O2 and illumination time. The degradation of diesel pollution in seawater was optimized by orthogonal experiment. According to the results, the removal rate of diesel is less than 30 % without any catalysts (only evaporation). The best effect exists when the dose of catalysts was 0.6 g/L, doping ratio of catalysts was 10%, initial concentration of diesel was 0.2 g/L, pH value was 8, concentration of H2O2 was 10 mg/L, illumination time was 1 h. The removal rate of diesel can reach 99.38 %. This study would make ZnO utilize sunlight more efficiently and accelerate the practical application of photocatalytic technology in organic pollutants treatment region.
关键词： visible light irradiation,photocatalyst,Er2O3,diesel pollutant,seawater,ZnO
更新于2025-09-09 09:28:46