Authors:Martial Duchamp, Vadim Migunov, Amir H. Tavabi, Adnan Mehonic, Mark Buckwell, Manveer Munde, Anthony J. Kenyon, and Rafal E. Dunin-Borkowski
Silicon oxide-based resistive switching devices show great potential for applications in nonvolatile random access memories. We expose a device to voltages above hard breakdown and show that hard oxide breakdown results in mixing of the SiOx layer and the TiN lower contact layers. We switch a similar device at sub-breakdown fields in situ in the transmission electron microscope (TEM) using a movable probe and study the diffusion mechanism that leads to resistance switching. By recording bright-field (BF) TEM movies while switching the device, we observe the creation of a filament that is correlated with a change in conductivity of the SiOx layer. We also examine a device prepared on a microfabricated chip and show that variations in electrostatic potential in the SiOx layer can be recorded using off-axis electron holography as the sample is switched in situ in the TEM. Taken together, the visualization of compositional changes in ex situ stressed samples and the simultaneous observation of BF TEM contrast variations, a conductivity increase, and a potential drop across the dielectric layer in in situ switched devices allow us to conclude that nucleation of the electroforming—switching process starts at the interface between the SiOx layer and the lower contact.
Authors:Haroune Rachid Ben Zine, Filiz Cinar Sahin, Zsolt E. Horváth, Zsolt Czigány, Ákos Horváth, Katalin Balázsi, and Csaba Balázsi
these dark spots are a mixture of Si 3 N 4 , and oxides are also present (Figure 5 ). The small bright particles on the grain surface (spot numbers 4 and 5) are steel particles as it is shown in the EDS spectra. In the case of the second mixture (316L+1
Authors:György Zoltán Radnóczi, Zoltán Herceg, and Tamás Rafael Kiss
thickness measurement, and this is estimated conservatively 2 fringes/image. In this case the lattice fringes i.e. rows of bright features parallel to the substrate surface are 1/2 a Si = 0.2716 nm apart corresponding to the (002) Si maximum in the Fourier
Authors:S. Hu, H. Shu, J.L. Yuan, J.Y. Gao, P.Y. Mu, C.Z. Ren, W. Sang, L.C. Guo, and H.B. Chen
–1.88±0.23 c 14.42±0.17 cd 13.50 c Wheat-oat 9.00 60.90±0.31 a –3.10±0.17 d 13.71±0.15 ab 12.26 bc Pure wheat ﬂour 62.94±0.56 c –4.34±0.21 e 14.09±0.19 abd 11.42 b L : brightness; a : (+) redness, (–) greenness; b : (+) yellowness, (–) blueness; ΔE
suitable camera's exposition time is set to a high enough value, in our case 30 s. Then, while holding the camera steady, a bright point of light is moved. With its long exposure time, the camera records all these moving points of light, creating a single
Authors:E. Kovács, P. Merész, Z. Kristóf, and E. Németh-Szerdahelyi
Colour, texture, pectin autolysis, membrane permeability and microstructure (SEM, TEM), β-galactosidase and polygalacturonase were studied in apricots (cv. Magyar kajszi) harvested in mature green, straw yellow, bright orange and deep orange stages. The L* increased from mature green to straw yellow then decreased from straw yellow to deep orange state. The a* values increased with ripening. The bright and deep orange apricots were significantly softer than the mature green and straw yellow ones and the membrane permeability increased with ripening. The presence of β-galactosidase enzyme was proved by immunoblotting analysis using monoclonal anti-β-galactosidase clone GAL-13 (Sigma) in all ripening stages. The enzyme activity was very low in mature green stage and increased significantly (P>95%) with increasing ripeness and during storage. The PG activity was very low in the mature green apricot. A significant (P>95%) increase was observed in the straw yellow apricot and in the riper fruits. The mature green apricot showed a regular, the straw yellow and bright orange samples showed a moderately regular tissue structure, while the tissue of the deep orange apricot collapsed (SEM). The cell wall and the middle lamella of the green apricot (TEM) were intact. Generally, there were intact cytoplasm membranes with some damaged parts. In the straw yellow apricot, the cell wall started to loosen, the middle lamella lost pectic polysaccharides. The structure of the cytoplasm was not recognisable, the tonoplast and the cytoplasm membrane were injured. The cell wall of the bright orange apricot was similar to that of the straw yellow ones. The middle lamella dissolved and hairy, fibrillar structure of cell wall was found in the deep orange samples.
Authors:C. Roets, S.H. Rose, M. Muller, and M. Manley
The effect of a pure endoxylanase (Xyn2) and endoglucanase (EgII) from Trichoderma reesei on bread flour quality were compared to a commercial endoxylanase from Aspergillus niger (Com-xyl) and a cellulase-xylanase cocktail from T. reesei (Cel-xyl). Effects of these enzymes on dough quality, bread weight, height and crumb softness were analysed. Results obtained during commercial-scale baking tests often differed from those obtained during laboratory-scale tests; indicating that results from laboratory-scale baking tests cannot be extrapolated to commercialscale bread production. Low levels of endoxylanase activity benefited bread height and volume without affecting slice brightness in commercial-scale tests. The addition of endoglucanases and α-amylases can also be advantageous resulting in less endoxylanase activity required to obtain similar results.
Authors:Zs. Albert, Zs. Erős-Honti, G. Solymossy, L. Kuznyák, A. Miskó, Cs. Deák, M. Ladányi, I. Terbe, and I. Papp
In this study two widely consumed Hungarian bell pepper cultivars ‘Hó’ and ‘Kárpia’, were examined. Aims of the investigations were to describe the postharvest behaviour of the cultivars and assign associated traits to the largely different shelf-life that is well known for these cultivars. ‘Hó’ is a white fruit flesh cultivar with average postharvest storability, while ‘Kárpia’ is of Capia type, with extended shelf-life. Postharvest water loss rates were measured, and differences between the cultivars were found. Interestingly, however, the longer shelf-life ‘Kárpia’ fruits showed higher water loss rate. Bright field microscopy was used to study the tissue structure of the outer pericarp of pepper fruits to find explanation for the good storability of ‘Kárpia’. Significantly more cell layers of the hypodermal collenchyma were found in ‘Kárpia’, than in ‘Hó’. Thicker cell walls were also found in this tissue but also in the epidermis. Fluorescent imaging confirmed these observations and also supported differences in the cuticular thickness between the cultivars. Our results highlight epidermal and hypodermal tissue structures as potential factors to influence the shelf-life of bell pepper fruits.