Bulk defect induced low-frequency noise in n+-p silicondiodes

The low-frequency 1/f-like noise of gated n⁺-p silicon diodes has been measured and analyzed in terms of trapping and detrapping of holes in defect centers located in the bulk section of the space charge region at 0.43 eV below the conduction band. Both the trap characteristics and their precise physical location are resolved from the noise measurements showing that the noise producing defect region moves closer to the metallurgical junction when forward bias is increased. The noise measurements independently confirm that thermal substrate pretreatments lower the defect density in the diodes fabricated in Czochralski (CZ) grown substrates. The defect centers are assumed to be associated with precipitated oxygen/dislocation complexes     

Silica supported cobalt Fischer–Tropsch catalysts: effect of pore diameter of support

The influence of the effect of average pore diameter of silica support on the physical and chemical properties of supported cobalt catalysts and their performance in the Fischer–Tropsch synthesis was investigated. Silicas with different mean pore diameter (20, 40, 60, 100 and 150 Å) were impregnated with cobalt nitrate to produce catalysts containing 20 wt.% cobalt. The metal crystallite size and degree of reduction was found to increase with increasing pore diameter of the support for supports with an average pore diameter larger or equal to 40 Å, and hence the dispersion decreased. In impregnated catalysts, the metal crystallites seems to appear in clusters on the support. With increasing average pore diameter, the size of these clusters increases. In the Fischer–Tropsch synthesis, the 100 Å supported catalyst proved to be the most active and selective catalyst for hydrocarbon formation. The C₅₊ and methane selectivity passed through a maximum and minimum at the 100 Å supported catalyst, respectively, which can be explained quantitatively using the reactant transport model proposed by Iglesia et al.     

Design and optimisation of a (FA)Q-learning-based HTTP adaptive streaming client

In recent years, HTTP (Hypertext Transfer Protocol) adaptive streaming (HAS) has become the de facto standard for adaptive video streaming services. A HAS video consists of multiple segments, encoded at multiple quality levels. State-of-the-art HAS clients employ deterministic heuristics to dynamically adapt the requested quality level based on the perceived network conditions. Current HAS client heuristics are, however, hardwired to fit specific network configurations, making them less flexible to fit a vast range of settings. In this article, a (frequency adjusted) Q-learning HAS client is proposed. In contrast to existing heuristics, the proposed HAS client dynamically learns the optimal behaviour corresponding to the current network environment in order to optimise the quality of experience. Furthermore, the client has been optimised both in terms of global performance and convergence speed. Thorough evaluations show that the proposed client can outperform deterministic algorithms by 11–18% in terms of mean opinion score in a wide range of network configurations.     

Effect of muscle and post-mortem rate of pH and temperature fall on antioxidant enzyme activities in beef

The aim of this study was to investigate the effect of muscle, inner and outer Musculus biceps femoris (IBF and OBF respectively) and Musculus longissimus dorsi (LD), on the post-mortem rate of pH and temperature fall, and the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) during simulated retail display. At day 0 of display (2 days post-mortem), the CAT and GSH-Px activities were lower in IBF than in OBF and LD (P < 0.001), and the SOD activity was lower in OBF compared to IBF and LD (P < 0.001). At day 10 of display, SOD and CAT activities had decreased in all three muscles compared to day 0 (P < 0.001), whereas the GSH-Px activity did increase with time of display. Across muscles, there were significant relationships between temperature fall, colour, lipid and colour stability and antioxidant enzyme activities.     

Antioxidant enzyme activities and antioxidant capacity in longissimus muscle from bulls fed diets rich in polyunsaturated fatty acids

The effect of a treatment diet composed of grass silage and concentrate including rapeseed (with/without feeding restriction) was compared with a control diet of maize silage/grass silage (70:30) and concentrate including soybean, on the antioxidant enzyme activities of fresh longissimus muscle from German Simmental bulls. Additionally, the effect of diet on antioxidant capacity (AOC) of hydrophilic and lipophilic antioxidants was evaluated in fresh and stored beef muscle using the FRAP-ferric reducing ability and TEAC – Trolox-equivalent antioxidant capacity assays at different reaction times. Catalase and superoxide dismutase activities were significantly higher in the treatment diet groups, and glutathione peroxidase activity was not different. AOC was not affected by the diet. However, storage affected the values of FRAP and TEAC assays, and the results were time-depending. 30 min were found like a minimum reaction time for both assays. Generally, AOC values of the hydrophilic antioxidants were significantly higher than lipophilic values.     

Stress analysis of Si1−xGex embedded source/drain junctions

The purpose of this paper is to evaluate the impact of the geometry of embedded Si_1−xGe_x source/drain junctions on the stress field. Stress simulations were performed using TSUPREM4 2D software to further investigate the elastic strain relaxation as a function of Si_1−xGe_x alloy active size, in the regime where no plastic relaxation is present. Moreover, the role of the epilayer thickness and the Ge content on the stress levels is also discussed. The work is complemented with experimental Raman spectroscopy.     

Temperature influence on the gate-induced floating body effect parameters in fully depleted SOI nMOSFETs

The temperature influence on the gate-induced floating body effect (GIFBE) in fully depleted (FD) silicon-on-insulator (SOI) nMOSFETs is investigated, based on experimental results and two-dimensional numerical simulations. The GIFBE behavior will be evaluated taking into account the impact of carrier recombination and of the effective electric field mobility degradation on the second peak in the transconductance (gm). This floating body effect is also analyzed as a function of temperature. It is shown that the variation of the studied parameters with temperature results in a “C” shape of the threshold voltage corresponding with the second peak in the gm curve.     

In Vitro Zinc Protoporphyrin IX Formation in Different Meat Sources Related to Potentially Important Intrinsic Parameters

For several years, researchers have studied the formation of zinc protoporphyrin IX in meat, as it is considered to be an important natural colouring agent in dry cured or fermented meat products in the absence of nitrite and/ or nitrate. Until now, however, mainly pork meat is used for these investigations. The goal of this research was to relate in vitro zinc protoporphyrin IX and protoporphyrin IX formation in eight meat sources (chicken, turkey, pork, lamb, beef, veal, horse and porcine liver) to eight intrinsic parameters using partial least squares regression (PLS) analysis. Significant differences in pH, initial metmyoglobin formation, metmyoglobin reduction ability, total heme, zinc chelatase activity, and total iron and zinc concentration between meat sources were found. Water activity, however, was not significantly different between meat sources. Liver tissue and horse meat showed the best ability to form zinc protoporphyrin IX. Formation of protoporphyrin IX was limited in all meat sources. PLS analysis revealed that mainly zinc chelatase activity, followed by total heme, total iron and zinc content, were predominant intrinsic parameters to explain variations in zinc protoporphyrin IX formation. These findings could be important for meat industry in order to establish the production of red coloured nitrite-free meat products.     

Explaining the parameters of the electron valence-band tunneling related Lorentzian noise in fully depleted SOI MOSFETs

The behavior of the Lorentzian noise overshoot time constant /spl tau/ and plateau amplitude is investigated in fully depleted silicon-on-insulator MOSFETs with the back gate in accumulation. It is shown that /spl tau/ is identical for long-channel nand p-MOSFETs in the gate overdrive voltage range studied. For shorter lengths (L = 0.12 /spl mu/m), a slight reduction of /spl tau/ for the p-MOSFETs and an increase for the short n-MOSFETs has been found. The observations will be explained by considering both the injection of majority carriers in the floating body through electron valence-band tunneling and the dynamic resistance of the source-body and gate-body junction.