Search results for "BT"

Controlling the mode of operation of organic transistors through side chain engineering

2016

Electrolyte-gated organic transistors offer low bias operation facilitated by direct contact of the transistor channel with an electrolyte. Their operation mode is generally defined by the dimensionality of charge transport, where a field-effect transistor allows for electrostatic charge accumulation at the electrolyte/semiconductor interface, whereas an organic electrochemical transistor (OECT) facilitates penetration of ions into the bulk of the channel, considered a slow process, leading to volumetric doping and electronic transport. Conducting polymer OECTs allow for fast switching and high currents through incorporation of excess, hygroscopic ionic phases, but operate in depletion mode…

Impact of contact resistance on the electrical properties of MoS2 transistors at practical operating temperatures

2017

Molybdenum disulphide (MoS2) is currently regarded as a promising material for the next generation of electronic and optoelectronic devices. However, several issues need to be addressed to fully exploit its potential for field effect transistor (FET) applications. In this context, the contact resistance, RC, associated with the Schottky barrier between source/drain metals and MoS2 currently represents one of the main limiting factors for suitable device performance. Furthermore, to gain a deeper understanding of MoS2 FETs under practical operating conditions, it is necessary to investigate the temperature dependence of the main electrical parameters, such as the field effect mobility (μ) an…

Grain growth in Na 0.5 Bi 0.5 TiO 3 -based solid solutions

2019

This paper discusses effects of different dopants, sintering technique and parameters on microstructure and properties of pure and Yb, Er-doped Na0.5Bi0.5TiO3 (NBT). All stoichiometric compositions follow the abnormal grain growth mechanism (AGG) and exhibit a bimodal grain size distribution. Bi over-stoichiometry, two step sintering and hot pressing are effective inhibitors of AGG. Microstructure of sintered NBT greatly influences such properties as dielectric permittivity and depolarization temperature.

A subthreshold, low-power, RHBD reference circuit, for earth observation and communication satellites

2015

A low-power, wide temperature range, radiation tolerant CMOS voltage reference is presented. The proposed reference circuit exhibits a voltage deviation of 0.8mV for 3-MeV protons total ionization dose of 2Mrad and a voltage deviation of 3.8mV for 10-keV X-rays total ionization dose of 4Mrad while being biased at the nominal supply voltage of 0.75V during X-ray irradiation. In addition, the circuit consumes only 4μW and exhibits a measured Temperature Drift of 15ppm/°C for a temperature range of 190°C (−60°C to 130°C) at the supply voltage of 0.75V. It utilizes only CMOS transistors, operating in the subthreshold regime, and poly-silicon resistors without using any diodes or external compon…

Designing portfolios of financial products via integrated simulation and optimization models

1999

We analyze the problem of debt issuance through the sale of innovative financial products. The problem is broken down to questions of designing the financial products, specifying the debt structure with the amount issued in each product, and determining an optimal level of financial leverage. We formulate a hierarchical optimization model to integrate these three issues and provide constructive answers. Input data for the models are obtained from Monte Carlo simulation procedures that generate scenarios of holding period returns of the designed products. The hierarchical optimization model is specialized for the problem of issuing a portfolio of callable bonds to fund mortgage assets. The …

Temporal patterns in immune responses to a range of microbial insults (Tenebrio molitor).

2008

8 pages; International audience; Much work has elucidated the pathways and mechanisms involved in the production of insect immune effector systems. However, the temporal nature of these responses with respect to different immune insults is less well understood. This study investigated the magnitude and temporal variation in phenoloxidase and antimicrobial activity in the mealworm beetle Tenebrio molitor in response to a number of different synthetic and real immune elicitors. We found that antimicrobial activity in haemolymph increased rapidly during the first 48h after a challenge and was maintained at high levels for at least 14 days. There was no difference in the magnitude of responses …

Nuclear charge radii of potassium isotopes beyond N=28

2014

We report on the measurement of optical isotope shifts for 38, 39, 42, 44, 46–51 K relative to 47 K from which changes in the nuclear mean square charge radii across the N = 28 shell closure are deduced. The investigation was carried out by bunched-beam collinear laser spectroscopy at the CERN-ISOLDE radioactive ion-beam facility. Mean square charge radii are now known from 37K to 51K, covering all ν f7/2-shell as well as all νp3/2-shell nuclei. These measurements, in conjunction with those of Ca, Cr, Mn and Fe, provide a first insight into the Z dependence of the evolution of nuclear size above the shell closure at N = 28

Study of the influence of temperature and precipitations on the levels of BTEX in natural waters.

2013

Assessment of seasonal changes in surface water quality is an important aspect for evaluating temporal variation of water due to natural or anthropogenic inputs of point and non-point sources. The objective of this paper was to investigate the influence of seasonal temperature fluctuations and precipitations on the levels of BTEX in natural waters. Principal component analysis (PCA) was used to evaluate the seasonal correlations of BTEX levels in water and to extract the parameters that are most important in assessing seasonal variations of water quality. This study was carried out as a part of VOCs monitoring program in natural water samples from Mediterranean coast. To carry out this proj…

2019

The Gram-positive soil bacterium Bacillus subtilis relies on the glutamine synthetase and the glutamate synthase for glutamate biosynthesis from ammonium and 2-oxoglutarate. During growth with the carbon source glucose, the LysR-type transcriptional regulator GltC activates the expression of the gltAB glutamate synthase genes. With excess of intracellular glutamate, the gltAB genes are not transcribed because the glutamate-degrading glutamate dehydrogenases (GDHs) inhibit GltC. Previous in vitro studies revealed that 2-oxoglutarate and glutamate stimulate the activator and repressor function, respectively, of GltC. Here, we have isolated GltC variants with enhanced activator or repressor fu…

Global Distribution and Evolution of Mycobacterium bovis Lineages

2020

Mycobacterium bovis is the main causative agent of zoonotic tuberculosis in humans and frequently devastates livestock and wildlife worldwide. Previous studies suggested the existence of genetic groups of M. bovis strains based on limited DNA markers (a.k.a. clonal complexes), and the evolution and ecology of this pathogen has been only marginally explored at the global level. We have screened over 2,600 publicly available M. bovis genomes and newly sequenced four wildlife M. bovis strains, gathering 1,969 genomes from 23 countries and at least 24 host species, including humans, to complete a phylogenomic analyses. We propose the existence of four distinct global lineages of M. bovis (Lb1, …