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Author(s):  
Satoshi Inoue ◽  
Yoshiaki HATTORI ◽  
Masatoshi KITAMURA

Abstract A trimethylsilyl-monolayer modified by vacuum ultraviolet (VUV) light has been investigated for use in solution-processed organic thin-film transistors (OTFTs). The VUV irradiation changed a hydrophobic trimethylsilyl-monolayer formed from hexamethyldisilazane vapor into a hydrophilic surface suitable for solution processing. The treated surface was examined via water contact angle measurement and X-ray photoelectron spectroscopy. An appropriate irradiation of VUV light enabled the formation of a dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) film on a modified monolayer by spin-coating. Consequently, the C8-BTBT-based OTFT with a monolayer modified for an optimal VUV irradiation time exhibited a field-effect mobility up to 4.76 cm2 V−1 s−1. The partial monolayer modification with VUV can be adapted to a variety of solution-processes and organic semiconductors for prospective printed electronics.


2022 ◽  
pp. 095400832110665
Author(s):  
Lian Liu ◽  
Haitao Duan ◽  
Wen Zhan ◽  
Shengpeng Zhan ◽  
Dan Jia ◽  
...  

Exposing engineering plastics to UV irradiation can easily destroy the original molecular structure of the materials and consequently affect their tribological properties. This study investigated the effects of UV irradiation on the molecular structure of typical engineering plastics, such as polytetrafluoroethylene (PTFE) and polyether ether ketone (PEEK), and on their tribological properties under heavy loads (20 MPa). The surface morphology results showed that the appearance of PEEK changed significantly under UV irradiation. However, the change in PTFE was negligible. Under micromorphology, the processing lines of the two materials gradually became lighter with increasing UV irradiation time. The resulting infrared spectra showed that the molecular chains of both materials were broken, and new functional groups were formed under UV irradiation. Tribology testing demonstrated that with prolonged UV irradiation, the average PTFE coefficient of friction remained relatively stable, whereas that of PEEK was approximately 0.55. As the UV irradiation time increased, the wear rate of PTFE increased significantly, whereas that of PEEK showed no significant change.


2022 ◽  
pp. 37-43
Author(s):  
G. K. Zhanbolatova ◽  
A. Z. Miniyazov ◽  
T. R. Tulenbergenov ◽  
I. A. Sokolov ◽  
O. S. Bukina

This paper presents the results of a study of the formation of a carbidized layer under various experimental conditions and the choice of optimal parameters for carbidization of a tungsten surface under plasma irradiation. To study the effect of the surface temperature of a tungsten sample and the duration of plasma irradiation, experiments were carried out at a sample surface temperature of 1300 °C and 1700 °C with an irradiation duration of 300–2400 s. Analysis of the research results showed that the maximum formation of W2C on the surface is observed at a test temperature of 1700 °C. At a temperature of 1300 °C, the phase composition of the carbidized layer depends on the duration of plasma irradiation. According to the literature analysis, the formation of WC occurs on the surface of tungsten, from which C diffuses into the particle and forms the underlying layer of W2C. With an increase in the ion fluence, depending on the irradiation time and the temperature of the sample surface, the diffusion of C into W accelerates, the WC content decreases, and W2C becomes the dominant carbide compound.


2022 ◽  
Author(s):  
G. Roshini ◽  
V. Sathish ◽  
S. Manigandan ◽  
A. Tamilarasi ◽  
E. Priyanka

Abstract In this paper, the highly stable Ag/CdS-WO2 nanocomposite was fabricated by a facile and capping agent-free hydrothermal technique. The fabricated Ag doped CdS-WO2 nanocomposite were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and UV-vis diffuse reflectance (DRS) spectroscopy. The photocatalytic performance of synthesized photocatalysts was evaluated for the photodegradation of rhodamine B (Rh B) under visible light irradiation (VLI). The parameters used for the optimization of the photocatalyst were pH, catalyst dose, oxidant dose, and irradiation time. Based on this, a possible reaction mechanism for the enhancement of photocatalytic activity of Ag/CdS-WO2 has been proposed. Hence, we have a tendency to believe it might be a promising material that may be used for the photodegradation of organic pollutants present in wastewater.


2022 ◽  
Author(s):  
Sabina Markelj ◽  
Matic Pečovnik ◽  
Thomas Schwarz-Selinger ◽  
Mitja Kelemen

Abstract In this work the synergism between displacement damage creation and presence of hydrogen isotopes was studied. Tungsten samples were irradiated by 10.8 MeV W ions with or without the presence of D ions with two different energies of 300 eV/D and 1000 eV/D and different temperatures. In order to compare the results obtained with different exposure parameters the samples were afterwards additionally exposed to D ions at 450 K to populate the created defects. By increasing the W irradiation time, ion flux and energy, the increase of D concentration and D retention was observed as measured by nuclear reaction analysis and thermal desorption spectroscopy. By fitting the D depth profiles and D desorption spectra by the rate equation code MHIMS-R we could see that additional fill-levels were populated with higher flux and ion energy which ends up in higher final D concentration and retention as compared to experiments with lower D flux and energy.


2022 ◽  
Author(s):  
G. Roshini ◽  
Sathish Vilvanathan ◽  
S. Manigandan ◽  
A. Tamilarasi ◽  
E. Priyanka

In this paper, the highly stable Ag/CdS-WO2 nanocomposite was fabricated by a facile and capping agent-free hydrothermal technique. The fabricated Ag-doped CdS-WO2 nanocomposite was characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and UV-vis diffuse reflectance (DRS) spectroscopy. The photocatalytic performance of synthesized photocatalysts was evaluated for the photodegradation of rhodamine B (RhB) under visible light irradiation (VLI). The parameters used for the optimization of the photocatalyst were pH, catalyst dose, oxidant dose, and irradiation time. Based on this, a possible reaction mechanism for the enhancement of the photocatalytic activity of Ag/CdS-WO2 has been proposed. Hence, we have a tendency to believe it might be a promising material that may be used for the photodegradation of organic pollutants present in wastewater.


Nanomaterials ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 152
Author(s):  
Aristeidis Stathis ◽  
Zoi Bouza ◽  
Ioannis Papadakis ◽  
Stelios Couris

In the present work the impact of in situ photoreduction, by means of ultraviolet (UV) irradiation, on the nonlinear optical response (NLO) of some graphene oxide (GO), fluorographene (GF), hydrogenated fluorographene (GFH) and graphene (G) dispersions is studied. In situ UV photoreduction allowed for the extended modification of the degree of functionalization (i.e., oxidization, fluorination and hydrogenation), leading to the effective tuning of the corresponding sp2/sp3 hybridization ratios. The nonlinear optical properties of the studied samples prior to and after UV irradiation were determined by means of the Z-scan technique using visible (532 nm), 4 ns laser excitation, and were found to change significantly. More specifically, while GO’s nonlinear optical response increases with irradiation time, GF and GFH present a monotonic decrease. The graphene dispersions’ nonlinear optical response remains unaffected after prolonged UV irradiation for more than an hour. The present findings demonstrate that UV photoreduction can be an effective and simple strategy for tuning the nonlinear optical response of these graphene derivatives in a controllable way, resulting in derivatives with custom-made responses, thus more suitable for different photonic and optoelectronic applications.


2022 ◽  
Vol 12 (1) ◽  
pp. 192-198
Author(s):  
Jiajia Deng ◽  
Jie Pan ◽  
Liming Yu ◽  
Yuhui Wang ◽  
Weihua Zhang ◽  
...  

Gelatin methacrylate (GelMA) hydrogels are a promising material for use in a variety of tissue engineering applications. Herein, we focused on identifying the optimal irradiation time necessary to photopolymerize GelMA hydrogels with visible blue light in a manner that did not adversely impact the biophysical properties of these cell-containing gels. We assessed the toxic effects of different irradiation times (3, 5, 10, 20 and 40 seconds) on BMMSCs encapsulated in a GelMA hydrogel using lithium phenyl-2,4,6 trimethylbenzoylphosphinate (LAP) as a photoinitiator. Both CCK-8 assays and Live-Dead staining were used to measure BMMSCs viability. We observed increasing compression strength as a function of increased irradiation time, although this corresponded to a reduction in swelling ratio and pore sizes. We ultimately found that when using LAP as a photoinitiator, the optimal irradiation time was 5–10 seconds, which was suitable for bone tissue engineering application. Ultimately we determined that a 5 second irradiation time was optimal for studies of encapsulated stem cells.


2022 ◽  
Vol 964 (1) ◽  
pp. 012028
Author(s):  
Anh Thi-Kim Tran ◽  
Nhung Thi-Tuyet Hoang ◽  
Tien Thuy Hoang Nguyen

Abstract The synthesis of TiO2-chitosan-glycerol (TiCsG) beads was prepared to determine the optimum condition for dye removal under natural sunlight. By using the orthogonal array design with five parameters (ratio of TiO2/Chitosan, initial concentration of dyes, pH of solution, irradiation time, dose of TiCsG) to analyze their interaction such as well as optimizing the photocatalytic process. The significant parameters influent in the removal of Acid Blue 193, MO, NWY dyes were irradiation time (p = 0.011) and the ratio of TiO2/chitosan (p = 0.025), while the initial concentration of dyes, pH of dye solution and dose of TiCsG were unimportant factors with p > 0.05. The optimum of factors based on the ratio of signal per noise to attain the highest dye removal ability of TiCsG was the percentage of TiO2/chitosan = 2 % w/w (level 2), initial concentration of dye at level 5 (10 mg/L of AB 193, 5 mg/L for MO and 100 mg/L for NWY), pH =4.5 (level 2), irradiation time =1.5 h (level 5) and dose of TiCsG =0.2 g/mL (level 4).


2021 ◽  
Vol 12 (1) ◽  
pp. 385
Author(s):  
Martina Kocijan ◽  
Lidija Ćurković ◽  
Igor Bdikin ◽  
Gonzalo Otero-Irurueta ◽  
María J. Hortigüela ◽  
...  

This work presents the immobilisation of titanium dioxide (TiO2) nanoparticles (NPs) and reduced graphene oxide (rGO)-TiO2 nanocomposite on glass sheets for photocatalytic degradation of methylene blue (MB) under different radiation sources such as ultraviolet and simulated solar radiation. The TiO2 NPs and rGO-TiO2 nanocomposite were synthesised through a simple hydrothermal method of titanium isopropoxide precursor followed by calcination treatment. Deposition of prepared photocatalysts was performed by spin-coating method. Additionally, ethylene glycol was mixed with the prepared TiO2 NPs and rGO-TiO2 nanocomposite to enhance film adhesion on the glass surface. The photocatalytic activity under ultraviolet and simulated solar irradiation was examined. Further, the influence of different water matrices (milli-Q, river, lake, and seawater) and reactive species (h+, •OH, and e−) on the photocatalytic efficiency of the immobilised rGO/TiO2 nanocomposite was careful assessed. MB dye photocatalytic degradation was found to increase with increasing irradiation time for both irradiation sources. The immobilisation of prepared photocatalysts is very convenient for environment applications, due to easy separation and reusability, and the investigated rGO/TiO2-coated glass sheets demonstrated high efficiency in removing MB dye from an aqueous medium during five consecutive cycles.


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