scholarly journals Photoreductive synthesis of monodispersed Au nanoparticles with citric acid as reductant and surface stabilizing reagent

RSC Advances ◽  
2017 ◽  
Vol 7 (11) ◽  
pp. 6187-6192 ◽  
Author(s):  
Yasuhiro Shiraishi ◽  
Haruki Tanaka ◽  
Hirokatsu Sakamoto ◽  
Satoshi Ichikawa ◽  
Takayuki Hirai
Keyword(s):  
Citric Acid ◽  
Uv Irradiation ◽  
Room Temperature ◽  
Au Nanoparticles ◽  
Uv Light

UV irradiation of water containing HAuCl4 and citric acid at room temperature successfully produces monodispersed Au nanoparticles. The size of Au particles is easily tuned by the intensity of UV light and the amount of citric acid.

scholarly journals Enhanced Humidity Sensing Response of SnO2/Silicon Nanopillar Array by UV Irradiation

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2141 ◽  
Author(s):  
Wei Li ◽  
Linlin Wang ◽  
Yun Cai ◽  
Peifeng Pan ◽  
Jinze Li ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Response Time ◽  
Specific Surface ◽  
Uv Irradiation ◽  
Recovery Time ◽  
Room Temperature ◽  
Uv Light ◽  
Humidity Sensing ◽  
Potential Applications ◽  
Humidity Sensitivity

In this work, a silicon nanopillar array was created with nanosphere lithography. SnO2 film was deposited on this nanostructure by magnetron sputtering to form an SnO2/silicon nanopillar array sensor. The humidity sensitivity, response time, and recovery time were all measured at room temperature (25 °C) with UV or without UV irradiation. As a result, the humidity sensitivity properties were improved by enlarging the specific surface area with ordered nanopillars and irradiating with UV light. These results indicate that nanostructure sensors have potential applications in the field of sensors.

scholarly journals UV irradiation effect on the electrical properties of Pb2MoO5 single crystal

2018 ◽  
Vol 26 (2) ◽  
pp. 63-66
Author(s):  
I. P. Volnyanskaya ◽  
M. P. Trubitsyn ◽  
D. M. Volnianskii ◽  
D. S. Bondar
Keyword(s):  
Electrical Properties ◽  
Single Crystal ◽  
Uv Irradiation ◽  
Room Temperature ◽  
Uv Light ◽  
Dipole Moments ◽  
Irradiation Effect ◽  
Deep Traps ◽  
Temperature Dependences ◽  
Ac Field

Electrical properties of Pb2MoO5 single crystal were studied in AC field (f=1 kHz) after irradiation with UV light (290 K). It was found that UV irradiation caused appearance of maximums on permittivity ε and conductivity σ temperature dependences, which were observed around 530 K. The anomalies of ε and σ vanished after annealing at 700 K and could be restored by subsequent UV irradiation performed at room temperature. The magnitude of ε and σ peaks increased for higher exposition time. Above 600 K conductivity σ was practically independent on irradiation. It is proposed that photoelectrons induced by UV light, are trapped by Mo located -within the oxygen tetrahedrons with vacancy VO in one of the vertexes. The dipole moments of (MoO3) groups reorient at VO hopping through the tetrahedron vertexes. Annealing at 700 K thermally decomposes (MoO3)- complexes. For T>600 K behavior of σ(T) is determined by conduction currents and nearly insensitive to UV irradiation. At high temperatures the photoelectrons do not contribute to conductivity since they are bound in (MoO3)- centers, recombine with holes or re-captured by more deep traps.

UV irradiation induced formation of Au nanoparticles at room temperature: The case of pH values

2007 ◽  
Vol 301 (1-3) ◽  
pp. 174-183 ◽  
Author(s):  
Shengchun Yang ◽  
Yaping Wang ◽  
Qingfeng Wang ◽  
Ruili Zhang ◽  
Bingjun Ding
Keyword(s):  
Uv Irradiation ◽  
Room Temperature ◽  
Au Nanoparticles ◽  
Ph Values

UV light activated NO2gas sensing based on Au nanoparticles decorated few-layer MoS2thin film at room temperature

2018 ◽  
Vol 113 (8) ◽  
pp. 082103 ◽  
Author(s):  
Yong Zhou ◽  
Cheng Zou ◽  
Xiaogang Lin ◽  
Yongcai Guo
Keyword(s):  
Room Temperature ◽  
Au Nanoparticles ◽  
Uv Light

The Study of Photoreversibility, Photopolimerization and Photocleavage Properties of Polyurethane Coumarin by Means of Electronic Spectrometry and AFM Methods

2017 ◽  
Vol 68 (7) ◽  
pp. 1632-1635
Author(s):  
Silviu Gurlui ◽  
Emil Buruiana ◽  
Ioan Gabriel Sandu ◽  
Mitachi Strat
Keyword(s):  
Uv Irradiation ◽  
Room Temperature ◽  
Dimethyl Formamide ◽  
Photon Excitation ◽  
Photochemical Properties ◽  
Film State

The spectroscopic and photochemical properties of polyurethane coumarin (PUC) in dimethyl sulf-oxide (DMSO), thetra hydro furan (THF), dimethyl formamide (DMF) and film state were investigated at room temperature under one photon excitation. The results show that under irradiation of l ] 310 nm photodimerization process are increased and under UV irradiation with l[ 260 nm, photocleavage of polymer have been evidenced, too.

Synergistic effects of SnO2 and Au nanoparticles decorated on WS2 nanosheets for flexible, room-temperature CO gas sensing

2021 ◽  
Vol 332 ◽  
pp. 129493
Author(s):  
Jae-Hun Kim ◽  
Jin-Young Kim ◽  
Ali Mirzaei ◽  
Hyoun Woo Kim ◽  
Sang Sub Kim
Keyword(s):  
Room Temperature ◽  
Au Nanoparticles ◽  
Gas Sensing ◽  
Synergistic Effects ◽  
Ws2 Nanosheets ◽  
Co Gas

scholarly journals Effect of Water Leaching on Photodegraded Scots Pine and Spruce Timbers Monitored by FTIR Spectroscopy

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 833
Author(s):  
Edina Preklet ◽  
László Tolvaj ◽  
Eszter Visi-Rajczi ◽  
Tamás Hofmann
Keyword(s):  
Ftir Spectroscopy ◽  
Scots Pine ◽  
Uv Irradiation ◽  
Chemical Elements ◽  
Uv Light ◽  
Carbonyl Groups ◽  
Water Leaching ◽  
Absorption Bands ◽  
Chemical Changes ◽  
Absorption Increase

The goal of this research was the systematic study and comparison of the divided individual effects of UV light irradiation and water leaching during artificial weathering. Spruce (Picea abies Karst.) and Scots pine (Pinus sylvestris L.) samples were irradiated by ultraviolet (UV) light. Another sequence of samples was treated with the combination of UV irradiation and water leaching. The total extent of UV treatment was 20 days for both series of samples. Time relation of UV irradiation and water leaching was 2:1. The chemical changes were observed by FTIR spectroscopy. The difference spectrum was used for determination of the chemical changes. Degradation of lignin was greater for the leached samples than for the pure UV treated samples. Scots pine suffered greater lignin degradation than spruce, and produced higher absorption increase on the absorption region of unconjugated carbonyls. The unconjugated carbonyl groups were the most responsive chemical elements to leaching. Spruce was more susceptible to leaching of unconjugated carbonyl groups than Scots pine. Two absorption bands of unconjugated carbonyl groups at 1706 and 1764 cm−1 wavenumbers were produced by photodegradation. The absorption band at 1764 cm−1 was more sensitive to water leaching than the band at 1706 cm−1.

scholarly journals UV-induced neuronal degeneration in the rat cerebral cortex

2021 ◽  
Author(s):  
Mariko Nakata ◽  
Masayuki Shimoda ◽  
Shinya Yamamoto
Keyword(s):  
Uv Irradiation ◽  
Neuronal Degeneration ◽  
Uv Light ◽  
Brain Lesion ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Heme Oxygenase 1 ◽  
Dependent Manner ◽  
Focal Brain Injury ◽  
The Brain ◽  
And Oxidative Stress

Abstract Irradiation with ultraviolet (UV) light on the cortical surface can induce a focal brain lesion (UV lesion) in rodents. In the present study, we investigated the process of establishing a UV lesion. Rats underwent UV irradiation (365 nm wavelength, 2.0 mWh) over the dura, and time-dependent changes in the cortical tissue were analyzed histologically. We found that the majority of neurons in the lesion started to degenerate within 24 hours and the rest disappeared within 5 days after irradiation. UV-induced neuronal degeneration progressed in a layer-dependent manner. Moreover, UV-induced terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positivity and heme oxygenase-1 (HO-1) immunoreactivity were also detected. These findings suggest that UV irradiation in the brain can induce gradual neural degeneration and oxidative stress. Importantly, UV vulnerability may vary among cortical layers. UV-induced cell death may be due to apoptosis; however, there remains a possibility that UV-irradiated cells were degenerated via processes other than apoptosis. The UV lesion technique will not only assist in investigating brain function at a targeted site but may also serve as a pathophysiological model of focal brain injury and/or neurodegenerative disorders.

scholarly journals Zirconium-Doped Chromium IV Oxide Nanocomposites: Synthesis, Characterization, and Photocatalysis towards the Degradation of Organic Dyes

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 117
Author(s):  
Zahir Muhammad ◽  
Farman Ali ◽  
Muhammad Sajjad ◽  
Nisar Ali ◽  
Muhammad Bilal ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Solid State ◽  
Room Temperature ◽  
Organic Dyes ◽  
Uv Light ◽  
Heterogeneous Photocatalysis ◽  
Ft Ir ◽  
Complete Mineralization

Degradation of organic dyes and their byproducts by heterogeneous photocatalysts is an essential process, as these dyes can be potentially discharged in wastewater and threaten aquatic and xerophyte life. Therefore, their complete mineralization into nontoxic components (water and salt) is necessary through the process of heterogeneous photocatalysis. In this study, Zr/CrO2 (Zirconium-doped chromium IV oxide) nanocomposite-based photocatalysts with different compositions (1, 3, 5, 7 & 9 wt.%) were prepared by an environmentally friendly, solid-state reaction at room temperature. The as-prepared samples were calcined under air at 450 °C in a furnace for a specific period of time. The synthesis of Zr/CrO2 photocatalysts was confirmed by various techniques, including XRD, SEM, EDX, FT-IR, UV-Vis, and BET. The photocatalytic properties of all samples were tested towards the degradation of methylene blue and methyl orange organic dyes under UV light. The results revealed a concentration-dependent photocatalytic activity of photocatalysts, which increased the amount of dopant (up to 5 wt.%). However, the degradation efficiency of the catalysts decreased upon further increasing the amount of dopant due to the recombination of holes and photoexcited electrons.

Optimization of ultraviolet irradiation of Clarias gariepinus (Burchell, 1822) eggs for androgen production

Zygote ◽  
2021 ◽  
pp. 1-6
Author(s):  
Victor Tosin Okomoda ◽  
Haziqah Jumahat Nursyaza ◽  
Ijabo Oga Samuel ◽  
Anuar Hassan ◽  
Abraham Sunday Oladimeji ◽  
...  
Keyword(s):  
Survival Rate ◽  
Uv Irradiation ◽  
Uv Light ◽  
Clarias Gariepinus ◽  
African Catfish ◽  
Chromosome Counting ◽  
Complete Inactivation ◽  
Cell Cleavage ◽  
Optimal Protocol ◽  
Prolonged Duration

Summary The optimum distance and duration of ultraviolet (UV) irradiation for the complete inactivation of African catfish Clarias gariepinus egg nucleus was investigated in this study. The UV light was suspended above the unfertilized eggs at four distances (5, 10, 20 and 30 cm) and for five durations (1, 2, 3, 4 and 5 min). Then, the irradiated eggs were activated with sperm from diploid C. gariepinus and cold shocked at 5°C for 5 min just moments before cell cleavage. Ploidy analysis was performed using karyotype chromosome counting. The results obtained suggested that the further the distance, the better the hatchability rate, however prolonged duration seemed to significantly reduced hatchability. All treatments with surviving progenies at the end of the study showed evidence of successfully diploid gynogen (2n = 56) induction at different percentages. However, the optimal protocol that gave a moderately high hatchability/survival rate and completely induced gynogens was exposure of the eggs to UV irradiation at 20 cm for 1 min. It was concluded that the distance and duration of UV irradiation affects gynogenetic induction in African catfish C. gariepinus.

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