Influence of atomic layer deposition chemistry on high-k dielectrics for charge trapping memories

In this work we report the performance of the SiO₂/Si₃N₄/HfO₂ and SiO₂/Si₃N₄/ZrO₂ stacks with emphasis on the influence of atomic layer deposition chemistry used for forming the HfO₂ and ZrO₂ blocking layers. Two Hf precursors were employed – tetrakis(ethylmethylamino)hafnium (TEMAH) and bis(methylcyclopentadienyl)methoxymethyl hafnium (HfD-04). For ZrO₂, tetrakis(ethylmethylamino)zirconium (TEMAZ) and bis(methylcyclopentadienyl)methoxymethyl zirconium (ZrD-04) were used as metal precursors. Ozone was used as the oxygen source. The structural characteristics of the stacks were examined by transmission electron microscopy and grazing incidence X-ray diffraction. The electrical properties of the stacks were studied using platinum-gated capacitor structures. The memory performance of the stacks was evaluated by write/erase (W/E) measurements, endurance and retention testing. Endurance measurements revealed the most important difference between the stacks. The films grown from TEMAH and TEMAZ could withstand a significantly higher number of W/E pulses (>3 × 10⁵ in the 10 V/?11 V, 10 ms regime), in comparison to the stacks made from HfD-04 and ZrD-04 precursors (<5 × 10³ W/E cycles). This difference in endurance characteristics is attributed mainly to the different deposition temperatures suited for these two precursors and the nature of the layer formed at the Si₃N₄/HfO₂ and the Si₃N₄/ZrO₂ interfaces.     

Feature Extraction for Crack Detection in Rain Conditions

The solution of the features selection problem is critical for robust detection of crack signals in noisy environment, varying from short-time impulses such as raindrops to the wide-band white Gaussian noise. In this paper, two novel feature selection methods were used to reduce an initial set of 90 features, 67 estimated in the time domain and 23 in the frequency domain, decreasing significantly the memory requirements and the computational complexity of a Radial-Basis-Function (RBF) cracks detector. The evaluation process is carried out in a database including of more than 6000 cracks, raindrops and simultaneous crack and raindrops signals. Additive white Gaussian noise is used to distort the real signals at ?20 to 20 dB Signal to Noise Ratio (SNR). The experimental results show that the number of features can be reduced to approximately 25, without affecting the classification rate of cracks and raindrops in the noisy signals, if the SNR is better than 0 dB. In noise-free environment a classification rate of 91% for a single crack/raindrop event is achieved using only five features. A different set of five features reaches a rate of 85% at 10 dB SNR.     

The effects of a seaweed extract in addition to nitrogen and boron fertilization on productivity,fruit maturation,leaf nutritional status and oil quality of the olive (Olea europaea L.) cultivar Koroneiki

BACKGROUND: There is not adequate literature on effects of seaweed extracts (SWE) on yield and nutritional status of olive trees as well as olive oil quality. In this work, a study of the effects of a seaweed extract applied foliarly (0.5% v/v) in addition to soil application of N (500 g NH₄NO₃ per tree) and B (150 g borax per tree) on productivity, fruit parameters, nutritional status and olive oil quality of a Greek olive cultivar was performed. RESULTS: In contrast to the trees treated with N (NH₄NO₃) or N + B (NH₄NO₃ + borax), the additional application of seaweed extract (treatments N + SWE and N + B orax + SWE) increased the productivity and oil content and accelerated maturation of the olive fruits. In particular, the best results concerning productivity, oil content and earliness of maturity (colour and firmness) were observed in the trees treated with N + B + SWE. The additional application of SWE also increased K, Fe and Cu concentrations and reduced the concentrations of Mn in olive leaves compared to the corresponding treatments without SWE. Total phenol concentration in oil was minimized in all fertilization treatments but, particularly, the additional application of SWE did not affect it. The application of N + B + SWE led to a significant increase in linolenic as well as oleic acid concentrations, and to a decline in palmitoleic, stearic and linoleic acid concentrations in olive oil. CONCLUSION: The fertilizer treatments of this experiment and especially the combination of NH₄NO₃ + borax + SWE should be recommended for the studied olive orchards, in order to increase tree productivity and improve their nutrition status and various olive oil quality parameters. Copyright © 2009 Society of Chemical Industry     

Rosemary powder filtrate improves the oxidative stability and antioxidant properties of rapeseed oil: potential applications for domestic cooking

Rapeseed oil is an important source of edible oil for the human diet but is also highly susceptible to oxidative deterioration. Previous research has demonstrated that rosemary powder and its extracts can increase the oxidative stability of rapeseed oil. In this study, the protective effect of ground rosemary powder (0.25–2.0%) against the oxidative degradation of filtered rapeseed oil was assessed. Rapeseed oil filtrate showed enhanced antioxidant capacity and higher induction periods (IP) based on Rancimat analysis. Lower conductivity changes and total colour differences, reduced malondialdehyde and conjugated dienes content, and higher levels of tocopherols and carotenoids were observed for the oils formulated with rosemary powder after 1.5 and 3 h of exposure to accelerated oxidation. The use of rosemary powder filtrate could be an effective way to protect rapeseed oil from oxidation during storage or cooking with domestic and commercial applications.     

Comparison of examination methods based on multiple-choice questions and constructed-response questions using personal computers

The aim of the present research was to compare the use of multiple-choice questions (MCQs) as an examination method, to the examination based on constructed-response questions (CRQs). Despite that MCQs have an advantage concerning objectivity in the grading process and speed in production of results, they also introduce an error in the final formulation of the score. The error is traced to the probability of answering a question by chance or based on an instinctive feeling, which does not enable the ascertainment of the knowledge of the whole background included in the question. In the present study, both MCQ and CRQ tests were given to examinees, in the framework of a computer-based learning system. Avoiding the procedure of mixed scoring, e.g. both positive and negative markings, a set of pairs of MCQs was composed. The MCQs in each pair were similar concerning the same topic, but this similarity was not evident for an examinee that did not possess adequate knowledge on the topic addressed in the questions of the pair. The examination based on these “paired” MCQs, by using a suitable scoring rule, when made to the same sample of students, οn the same topics and with the same levels of difficulty, gave results that were statistically indistinguishable with the grades produced by an examination based on CRQs, while both the “paired” MCQ test results and the CRQ test results differed significantly from those obtained from a MCQ test using positive-only scoring rule.     

Effect of heat treatment on milk protein functionality at emulsion interfaces. A review

Heat treatment affects the molecular structure of milk proteins at the interfaces of oil-in-water emulsions and in aqueous media. Experimental evidence of the impact of thermal processing on milk protein structure is presented and the contribution of whey proteins and caseins at film formation during emulsification is discussed. Recent advances in understanding the effect of heat treatment in milk protein functionality at emulsion interfaces are reviewed with particular emphasis on the emulsifying ability of whey proteins with or without the presence of the casein fraction. The major findings regarding the destabilizing mechanisms of oil-in-water emulsions brought about by heat-induced denaturation of milk proteins are presented. This paper aims to combine recent knowledge on how thermal processing of milk proteins affects their molecular configurations in bulk and particularly at interfaces, which in turn appear to be important with respect to the physico-chemical properties of milk protein-stabilized emulsions.     

Application of transition state theory to the study of materials containing acryloxy and acrylate units

We study the diffusion behavior of a probe, in monomers containing acryloxy and acrylate units that are commonly used in restorative dentistry. We apply a version of transition state theory with satisfactory results. Results show that transition state theory describes part of the underlying physics successfully thus reinforcing its applicability as a complement and extension to molecular dynamics simulations.     

Natural antioxidants from herbs and spices improve the oxidative stability and frying performance of vegetable oils

Lipid oxidation has been identified as the major deterioration process of vegetable oils. Undesirable effects are even more profound when food processing involves high temperatures in the presence of oxygen. Natural ground herbs (black pepper, ginger, turmeric, rosemary and oregano) were assessed for their antioxidant capacity, phenolic content and ability to improve the oxidative stability of vegetable oils. The most potent herb was incorporated in vegetable oils formulations which were subjected to consecutive frying cycles. The oxidative stability of the vegetable oils, the formation of conjugated dienes/trienes and the decimation of tocopherol levels after the frying process were assessed. Rosemary powder was the most effective antioxidant among the ones tested. The oxidative stability of tocopherol‐stripped corn oil with rosemary powder (1.53 ± 0.06 h) was significantly higher than the control (0.84 ± 0.02 h) and the oil with synthetic antioxidants (1.20 ± 0.03 h). Rosemary powder effectively improved the oxidative stability of sunflower (128.91%), olive (55.61%) and rapeseed (73.20%) oil during deep‐frying and prevented CD and CT formation in rapeseed oil.