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Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 202
Author(s):  
Miranda Martinez ◽  
Anil R. Chourasia

The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. The relative percentages of the constituents at the interface have been estimated by curve fitting the spectral data with the corresponding elemental and the oxide spectra. In the 200 °C samples, thermal diffusion of the titanium overlayer was observed. This resulted in the complete oxidation of the titanium overlayer to TiO2 upto a thickness of 0.9 nm of the overlayer. Elemental titanium resulting from the unreacted overlayer was observed to be more in the room temperature samples. The room temperature samples showed variation around 20% for the Ti-suboxide while an increasing trend was observed in the 200 °C samples.


Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 410
Author(s):  
Jennet R. Rabo ◽  
Makoto Takayanagi ◽  
Takashi Tsuchiya ◽  
Hideki Nakajima ◽  
Kazuya Terabe ◽  
...  

Scandium (Sc) and yttrium (Y) co-doped ZrO2 (ScYSZ) thin films were prepared on a SiO2-Si substrate via pulsed laser deposition (PLD) method. In order to obtain good quality thin films with the desired microstructure, various oxygen partial pressures (PO2) from 0.01 Pa to 10 Pa and substrate temperatures (Ts) from 25 °C to 800 °C were investigated. X-ray diffraction (XRD) patterns results showed that amorphous ScYSZ thin films were formed at room substrate temperature while cubic polycrystalline thin films were obtained at higher substrate temperatures (Ts = 200 °C, 400 °C, 600 °C, 800 °C). Raman spectra revealed a distinct Raman shift at around 600 cm−1 supporting a cubic phase. However, a transition from cubic to tetragonal phase can be observed with increasing oxygen partial pressure. Photoemission spectroscopy (PES) spectra suggested supporting analysis that more oxygen vacancies in the lattice can be observed for samples deposited at lower oxygen partial pressures resulting in a cubic structure with higher dopant cation binding energies as compared to the tetragonal structure observed at higher oxygen partial pressure. On the other hand, dense morphologies can be obtained at lower  PO2 (0.01 Pa and 0.1 Pa) while more porous morphologies can be obtained at higher PO2 (1.0 Pa and 10 Pa).


2021 ◽  
Vol 2 (4) ◽  
pp. 705-715
Author(s):  
Kimberley C. Carter ◽  
Léa Fieschi-Méric ◽  
Francesca Servini ◽  
Mark Wilkinson ◽  
David J. Gower ◽  
...  

Maintaining Gymnophiona in captivity provides opportunities to study the behaviour and life-history of this poorly known Order, and to investigate and provide species-appropriate welfare guidelines, which are currently lacking. This study focuses on the terrestrial caecilian Herpele squalostoma to investigate its sensitivity to disturbances associated with routine husbandry needed for monitoring and maintaining adequate wellbeing in captivity. Fossorial caecilians gradually pollute their environment in captivity with waste products, and substrate must be replaced at intervals; doing so disturbs the animals directly and via destruction of burrow networks. As inappetence is frequently associated with stress in amphibians, the percentage consumption of offered food types, river shrimp (Palaemon varians) and brown crickets (Gryllus assimilis), was measured as an indicator of putative stress following three routine substrate changes up to 297 days post-substrate change. Mean daily variation in substrate temperatures were also recorded in order to account for environmental influences on food consumption, along with nitrogenous waste in tank substrate prior to a substrate change and fresh top soil in order to understand the trade-off between dealing with waste accumulation and disturbing animals. We found a significant negative effect of substrate disturbance on food intake, but no significant effect of prey type. Variations in daily soil temperatures did not have a significant effect on food intake, but mean substrate temperature did. Additionally, substrate nitrogenous waste testing indicated little difference between fresh and tank substrate. In conclusion, this study provides a basis from which to develop further welfare assessment for this and other rarely kept and rarely observed terrestrial caecilian species.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1535
Author(s):  
Sergey Ishutkin ◽  
Vadim Arykov ◽  
Igor Yunusov ◽  
Mikhail Stepanenko ◽  
Vyacheslav Smirnov ◽  
...  

Chlorine processes are widely used for the formation of waveguide structures in InP-based optoelectronics. Traditionally, ICP etching of InP in a Cl2-based plasma requires substrate temperatures in the range of 150–200 °C. This condition is mandatory, since during the etching process low-volatility InClx components are formed and at insufficient temperatures are deposited onto substrate, leading to the formation of defects and further impossibility of the formation of waveguide structures. The need to preheat the substrate limits the application of chlorine processes. This paper presents a method of ICP etching an InP/InGaAsP heterostructure in a Cl2/Ar/N2 gas mixture. A feature of the developed method is the cyclic etching of the heterostructure without preliminary heating. The etching process starts at room temperature. In the optimal etching mode, the angle of inclination of the sidewalls of the waveguides reached 88.8° at an etching depth of more than 4.5 μm. At the same time, the surface roughness did not exceed 30 nm. The selectivity of the etching process with respect to the SiNx mask was equal to 9. Using the developed etching method, test integrated waveguide elements were fabricated. The fabricated active integrated waveguide (p-InP epitaxial layers were not removed) with a width of 2 μm demonstrated an optical loss around 11 ± 1.5 dB/cm at 1550 nm. The insertion loss of the developed Y- and MMI-splitters did not exceed 0.8 dB.


2021 ◽  
Vol 22 (4) ◽  
pp. 638-643
Author(s):  
M. Vuichyk ◽  
L. Rashkovets’kyi ◽  
S. Lavoryk ◽  
P. Lytvyn ◽  
K. Svezhentsova

In this work morphological, X-ray structural and optical studies of CdZnTe films grown by hot wall epitaxy method at relatively low substrate temperatures were performed. Possible mechanisms and processes of self-organization that occur during the growth of such structures are considered. It is shown that at thickness of film more than 130 nm on the surface, large (lateral size 150 - 200 nm, height - up to 10 nm) and small crystals are observed. The thicknesses and energy of the band gap width of the CdZnTe films grown at different growth times were determined. It is shown that the film absorption edge in the transmission spectra depends on the film thickness and the reasons for the shift of the film absorption edge are discussed.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5845
Author(s):  
Mariana Osiac ◽  
Iulian Boerasu ◽  
Madalin-Stefan Radu ◽  
Maria Jigau ◽  
Ion Tirca

Results on studies of pure tungsten oxide WO3 and 2, 3 and 4% Fe-doped WO3 grown on the sapphire substrates by reactive pulsed laser deposition technique are reported. From X-ray diffraction it results that the crystalline structures changed with the substrate temperature and the peaks diffraction having a small shift by the amount of Fe content in WO3 lattice was noticed. Scanning electron microscopy presented a random behavior of WO3 nanocrystallites size with substrate temperatures. In the presence of 2% Fe-doped WO3, the nanocrystallites size varied gradually from 60 nm to 190 nm as substrate temperature increased. The transmission spectra of the pure and 2, 3 and 4% Fe-doped WO3 films were obtained within the 300–1200 nm spectral range. The refractive index of WO3 and Fe-doped WO3 layers were calculated by the Swanepoel method. The refractive index of pure WO3 shows a variation from 2.35–1.90 and for 2% Fe-doped WO3 from 2.30–2.00, as the substrate temperature increased. The contents of 3 and 4% Fe-doped WO3 presented nearly identical values of the refractive index with pure and 2% Fe-doped WO3, in error limits, at 600 °C. The optical band gap changes with substrate temperature from 3.2 eV to 2.9 eV for pure WO3 and has a small variation with the Fe.


Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 907
Author(s):  
Justin M. Renkema ◽  
Jean-Philippe Parent

Popillia japonica Newman (Japanese beetle) is an invasive, polyphagous pest in North America, as adults feed on plant foliage and larvae on roots. Management in crops relies on foliar and soil applications of insecticides, but entomopathogenic nematodes (EPN) are effective biocontrol agents. In highbush blueberry, mulches (composts, woodshavings, sawdust, bark) are used for weed control and fertility. Therefore, our objective was to determine the effects of Heterorhabditis bacteriophora and Steinernema scarabaei on third-instar P. japonica in substrates commonly used as mulches in blueberry. In containers in the laboratory, larval mortality was 90–100% with H. bacteriophora for all substrates, but rates with S. scarabaei were lower and variable among substrates. A mixture of municipal compost + woodchips/sawdust resulted in 60% larval mortality without adding EPN, but few nematodes were recovered, indicating other causes of death. In a field microplot experiment in October, larval mortality rates were 50% at most for all EPN and substrate type combinations, likely due to lower than optimal soil and substrate temperatures for EPN survival and infectivity. Overall, a compost and woodchip/sawdust mulch should help suppress P. japonica populations in blueberry, and applying H. bacteriophora when temperatures are optimal to mulches can provide excellent larval control.


2021 ◽  
Vol 5 (4) ◽  
pp. 43
Author(s):  
Marina Efstratiou ◽  
John Christy ◽  
Daniel Bonn ◽  
Khellil Sefiane

The drying of bio-fluid drops results in the formation of complex patterns, which are morphologically and topographically affected by environmental conditions including temperature. We examine the effect of substrate temperatures between 20 °C and 40 °C, on the evaporative dynamics and dried deposits of foetal bovine serum (FBS) drops. The deposits consist of four zones: a peripheral protein ring, a zone of protein structures, a protein gel, and a central crystalline zone. We investigate the link between the evaporative behaviour, final deposit volume, and cracking. Drops dried at higher substrate temperatures in the range of 20 °C to 35 °C produce deposits of lower final volume. We attribute this to a lower water content and a more brittle gel in the deposits formed at higher temperatures. However, the average deposit volume is higher for drops dried at 40 °C compared to drops dried at 35 °C, indicating protein denaturation. Focusing on the protein ring, we show that the ring volume decreases with increasing temperature from 20 °C to 35 °C, whereas the number of cracks increases due to faster water evaporation. Interestingly, for deposits of drops dried at 40 °C, the ring volume increases, but the number of cracks also increases, suggesting an interplay between water evaporation and increasing strain in the deposits due to protein denaturation.


2021 ◽  
Vol 22 (3) ◽  
pp. 494-500
Author(s):  
P. Sagan ◽  
M. Frugynskyi ◽  
R. Mroczka ◽  
G. Wisz

Multicomponent spinel films were deposited on Ag/Si substrates by magnetron sputtering. Two substrate temperatures were used. XRD diffraction measurements show that the layers are composed of three metals oxides (Mn2O3, NiO, CoO). The presence of spinel phase is poorly visible. However, electron diffraction measurements (RHEED) clearly confirmed the presence of nanostructured spinel structure on top of the samples. Moreover, AFM measurements show that nanostructured spinel islands are present on the sample surface. The measurements validated that indeed, hierarchically organized spinel-oxides nanostructures were obtained. A possible model growth of the spinel nanostructures at different temperatures is discussed.


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