120 research outputs found
Implication of oxygen vacancies on current conduction mechanisms in TiN/Zr1−xAlxO2/TiN metal-insulator-metal structures
The dominating conduction mechanisms through TiN/Zr1−xAlxO2/TiN capacitors have been investigated over a wide temperature range (25 K to 430 K) in order to obtain information about the traps which cause the current transport. Single positive charged oxygen vacancies are the principal transport sites which participate in all mechanisms observed. However, the conduction mostly defined by intrinsic traps could also be strongly influenced by defects originating from undesirable high-k/metal gate interface reactions which could act as real traps or as transport sites
Magneto-Optical and Multiferroic Properties of Transition-Metal (Fe, Co, or Ni)-Doped ZnO Layers Deposited by ALD
ZnO doped with transition metals (Co, Fe, or Ni) that have non-compensated electron spins attracts particular interest as it can induce various magnetic phenomena and behaviors. The advanced atomic layer deposition (ALD) technique makes it possible to obtain very thin layers of doped ZnO with controllable thicknesses and compositions that are compatible with the main microelectronic technologies, which further boosts the interest. The present study provides an extended analysis of the magneto optical MO Kerr effect and the dielectric properties of (Co, Fe, or Ni)-doped ZnO films prepared by ALD. The structural, magneto optical, and dielectric properties were considered in relation to the technological details of the ALD process and the corresponding dopant effects. All doped samples show a strong MO Kerr behavior with a substantial magnetization response and very high values of the Kerr polarization angle, especially in the case of ZnO/Fe. In addition, the results give evidence that Fe-doped ZnO also demonstrates a ferroelectric behavior. In this context, the observed rich and versatile physical nature and functionality open up new prospects for the application of these nanostructured materials in advanced electronic, spintronic, and optical devices
Assessment of Feather Hydrolysate from Thermophilic Actinomycetes for Soil Amendment and Biological control Application, Int
ABSTRACT: Protein-rich hydrolysate from feather waste was obtained using a mixed culture of selected thermophilic actinomycete strains, and was tested for possible application as soil amendment and biological control agent. For this purpose, a 4 months laboratory experiment was carried out using two types of urban soils (Sofia, Bulgaria): native park soil and anthropogenic soil. The effect of the obtained hydrolysate on some soil parameters (pH, some enzyme activities and microbial activity), seed germination and ryegrass growth, and activity against some plant pathogenic fungi was studied. The results demonstrated that soil enrichment with the organic solution in low concentrations exerted a positive effect on soil urease and microbial activity, seed germination and ryegrass growth, and this trend was better expressed in the anthropogenic soils. Feather hydrolysate showed good activity against plant pathogenic fungi Fusarium solani, Fusarium oxysporum, Mucor sp. and Aspergillus niger. Produced antifungal compounds were isolated and partially characterized as amphiphilic peptides. To the best of our knowledge, antifungal peptides produced by Thermoactinomyces sp. have not been reported. Therefore, the feather hydrolysate obtained by means of the mixed culture of Thermoactinomyces strains has potential to be used as alternative organic amendment for restoration of contaminated soils and for accelerating ryegrass growth. It could successfully used also for as biocontrol agent applicable to crop plant soil
Function and failure of the fetal membrane : modelling the mechanics of the chorion and amnion
The fetal membrane surrounds the fetus during pregnancy and is a thin tissue composed of two layers, the chorion and the amnion. While rupture of this membrane normally occurs at term, preterm rupture can result in increased risk of fetal mortality and morbidity, as well as danger of infection in the mother. Although structural changes have been observed in the membrane in such cases, the mechanical behaviour of the human fetal membrane in vivo remains poorly understood and is challenging to investigate experimentally. Therefore, the objective of this study was to develop simplified finite element models to investigate the mechanical behaviour and rupture of the fetal membrane, particularly its constituent layers, under various physiological conditions. It was found that modelling the chorion and amnion as a single layer predicts remarkably different behaviour compared with a more anatomically-accurate bilayer, significantly underestimating stress in the amnion and under-predicting the risk of membrane rupture. Additionally, reductions in chorion-amnion interface lubrication and chorion thickness (reported in cases of preterm rupture) both resulted in increased membrane stress. Interestingly, the inclusion of a weak zone in the fetal membrane that has been observed to develop overlying the cervix would likely cause it to fail at term, during labour. Finally, these findings support the theory that the amnion is the dominant structural component of the fetal membrane and is required to maintain its integrity. The results provide a novel insight into the mechanical effect of structural changes in the chorion and amnion, in cases of both normal and preterm rupture
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Remote sensing data exploiration for geologic characterization of difficult targets : Laboratory Directed Research and Development project 38703 final report.
Characterizing the geology, geotechnical aspects, and rock properties of deep underground facility sites can enhance targeting strategies for both nuclear and conventional weapons. This report describes the results of a study to investigate the utility of remote spectral sensing for augmenting the geological and geotechnical information provided by traditional methods. The project primarily considered novel exploitation methods for space-based sensors, which allow clandestine collection of data from denied sites. The investigation focused on developing and applying novel data analysis methods to estimate geologic and geotechnical characteristics in the vicinity of deep underground facilities. Two such methods, one for measuring thermal rock properties and one for classifying rock types, were explored in detail. Several other data exploitation techniques, developed under other projects, were also examined for their potential utility in geologic characterization
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