888 resultados para Bias-ply tires
Resumo:
Genetic variation at the serotonin transporter-linked polymorphic region (5-HTTLPR) is associated with altered amygdala reactivity and lack of prefrontal regulatory control. Similar regions mediate decision-making biases driven by contextual cues and ambiguity, for example the "framing effect." We hypothesized that individuals hemozygous for the short (s) allele at the 5-HTTLPR would be more susceptible to framing. Participants, selected as homozygous for either the long (la) or s allele, performed a decision-making task where they made choices between receiving an amount of money for certain and taking a gamble. A strong bias was evident toward choosing the certain option when the option was phrased in terms of gains and toward gambling when the decision was phrased in terms of losses (the frame effect). Critically, this bias was significantly greater in the ss group compared with the lala group. In simultaneously acquired functional magnetic resonance imaging data, the ss group showed greater amygdala during choices made in accord, compared with those made counter to the frame, an effect not seen in the lala group. These differences were also mirrored by differences in anterior cingulate-amygdala coupling between the genotype groups during decision making. Specifically, lala participants showed increased coupling during choices made counter to, relative to those made in accord with, the frame, with no such effect evident in ss participants. These data suggest that genetically mediated differences in prefrontal-amygdala interactions underpin interindividual differences in economic decision making.
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Split-ring resonators represent the ideal route to achieve optical control of the incident light at THz frequencies. These subwavelength metamaterial elements exhibit broad resonances that can be easily tuned lithographically. We have realized a design based on the interplay between the resonances of metallic split rings and the electronic properties of monolayer graphene integrated in a single device. By varying the major carrier concentration of graphene, an active modulation of the optical intensity was achieved in the frequency range between 2.2 and 3.1 THz, achieving a maximum modulation depth of 18%, with a bias as low as 0.5 V.
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It has been previously observed that thin film transistors (TFTs) utilizing an amorphous indium gallium zinc oxide (a-IGZO) semiconducting channel suffer from a threshold voltage shift when subjected to a negative gate bias and light illumination simultaneously. In this work, a thermalization energy analysis has been applied to previously published data on negative bias under illumination stress (NBIS) in a-IGZO TFTs. A barrier to defect conversion of 0.65-0.75 eV is extracted, which is consistent with reported energies of oxygen vacancy migration. The attempt-to-escape frequency is extracted to be 10 6-107 s-1, which suggests a weak localization of carriers in band tail states over a 20-40 nm distance. Models for the NBIS mechanism based on charge trapping are reviewed and a defect pool model is proposed in which two distinct distributions of defect states exist in the a-IGZO band gap: these are associated with states that are formed as neutrally charged and 2+ charged oxygen vacancies at the time of film formation. In this model, threshold voltage shift is not due to a defect creation process, but to a change in the energy distribution of states in the band gap upon defect migration as this allows a state formed as a neutrally charged vacancy to be converted into one formed as a 2+ charged vacancy and vice versa. Carrier localization close to the defect migration site is necessary for the conversion process to take place, and such defect migration sites are associated with conduction and valence band tail states. Under negative gate bias stressing, the conduction band tail is depleted of carriers, but the bias is insufficient to accumulate holes in the valence band tail states, and so no threshold voltage shift results. It is only under illumination that the quasi Fermi level for holes is sufficiently lowered to allow occupation of valence band tail states. The resulting charge localization then allows a negative threshold voltage shift, but only under conditions of simultaneous negative gate bias and illumination, as observed experimentally as the NBIS effect. © 2014 AIP Publishing LLC.
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In this study, a combination of enzyme-linked receptor assay (ELRA) and yeast estrogen screen (YES) assay was firstly applied to determine whether automobile tires immersed in fresh water can leach chemicals, which display estrogenic activity. We optimized ELRA substituting the chromogene substrate by a luminescent one, and found that luminescent ELBA was more sensitive to 17 beta-estradiol (17 beta-E2) with a detection limit of 0.016 mu g/l, compared to 0.088 mu g/l in the chromogene version. In ELRA, all tire leachates obviously showed estrogenic activity, which was increased with duration of immersion. Moreover, the leachate from hackled tires showed more potent estrogenicity than that from the whole ones. In comparison to ELRA, no detectable estrogenic activity was found in all tire leachates with YES assay. The results from YES assay further evidenced that antiestrogenic compounds can be leached from tires. As tire leachates contain estrogenic compounds, they could be important pollution sources, potentially harmful to wildlife and human health. Thus, use of shredded tires as road fill or in landfill sites should arouse our attention.
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The unexpected decrease in measured responsivity observed in a specific GaN Schottky barrier photodetector (PD) at high reverse bias voltage was investigated and explained. Device equivalent transforms and small signal analysis were performed to analyse the test circuit. On this basis, a model was built which explained the responsivity decrease quantitatively. After being revised by this model, responsivity curves varying with bias voltage turned out to be reasonable. It is proved that the decrease is related to the dynamic parallel resistance of the photodiode. The results indicate that with a GaN Schottky PD, the choice of load resistance is restricted according to the dynamic parallel resistance of the device to avoid responsivity decay at high bias voltage.
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CaCu3Ti(4-x)Nb(x)O(12) (x = 0, 0.01, 0.08, 0.2) ceramics were fabricated by a conventional solid-state reaction method. The ceramics showed the body-centered cubic structure without any foreign phases and the grain size decreases with Nb doping. Two Debye-type relaxations were observed for the Nb-doped samples at low frequency and high frequency, respectively. The complex electric modulus analysis revealed that the surface layer, grains and grain boundaries contributed to the dielectric constant. The low-frequency dielectric constant relative to the surface layer decreased to a minimum and then increased with the dc bias voltage at 100 Hz, which were well explained in terms of a model containing two metal oxide semiconductors in series, confirming the surface layer in the ceramics. The shift voltage V-B corresponding to the minimal capacitance increased with increase of the composition x. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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We have studied the equilibrium and nonequilibrium electronic transports through a double quantum dot coupled to leads in a symmetrical parallel configuration in the presence of both the inter- and the intradot Coulomb interactions. The influences of the interdot interaction and the difference between dot levels on the local density of states (LDOS) and the differential conductance are paid special attention. We find an interesting zero-bias maximum of the differential conductance induced by the interdot interaction, which can be interpreted in terms of the LDOS of the two dots. Due to the presence of the interdot interaction, the LDOS peaks around the dot levels epsilon(i) are split, and as a result, the most active energy level which supports the transport is shifted near to the Fermi level of the leads in the equilibrium situation. (c) 2006 American Institute of Physics.
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Granules of waste tires were pyrolyzed tinder vacuum (3.5-10 kPa) conditions, and the effects of temperature and basic additives (Na2CO3, NaOH) on the properties of pyrolysis were thoroughly investigated. It was obvious that with or without basic additives, pyrolysis oil yield increased gradually to a maximum and subsequently decreased with a temperature increase from 450 degrees C to 600 degrees C, irrespective of the addition of basic additives to the reactor. The addition of NaOH facilitated pyrolysis dramatically, as a maximal pyrolysis oil yield of about 48 wt% was achieved at 550 degrees C without the addition of basic additives, while a maximal pyrolysis oil yield of about 50 wt% was achieved at 480 degrees C by adding 3 wt% (w/w, powder/waste tire granules) of NaOH powder. The composition analysis of pyrolytic naphtha (i.b.p. (initial boiling point) similar to 205 degrees C) distilled from pyrolysis oil showed that more dl-limonene was obtained with basic additives and the maximal content of dl-limonene in pyrolysis oil was 12.39 wt% which is a valuable and widely-used fine chemical. However, no improvement in pyrolysis was observed with Na2CO3 addition. Pyrolysis gas was mainly composed of H-2, CO, CH4, CO2, C2H4 and C2H6. Pyrolytic char had a surface area comparable to commercial carbon black, but its proportion of ash (above 11.5 wt%) was much higher.
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By using the technique of elastic recoil detection (ERD), we have measured the hydrogen profiles in a-Si:H/a-Si structure samples annealed at various temperatures with and without electrical bias, and investigated the influence of electrical bias on hydrogen diffusion. The results show that hydrogen diffusion in a-Si is significantly enhanced by the action of electrical bias. The existence of the excess carriers, which are introduced by electrical injection, is considered to be responsible for the enhancement of hydrogen diffusion, and the microprocess of hydrogen transport has been exploited.
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Up to now, in most of the research work done on the effect of hydrogen on a Schottky barrier, the hydrogen was introduced into the semiconductor before metal deposition. This letter reports that hydrogen can be effectively introduced into the Schottky barriers (SBs) of Au/n-GaAs and Ti/n-GaAs by plasma hydrogen treatment (PHT) after metal deposition on [100] oriented n-GaAs substrates. The Schottky barrier height (SBH) of a SB containing hydrogen shows the zero/reverse bias annealing (ZBA/RBA) effect. ZBA makes the SBH decrease and RBA makes it increase. The variations in the SBHs are reversible. In order to obtain obvious ZBA/RBA effects, selection of the temperature for plasma hydrogen treatment is important, and it is indicated that 100-degrees-C for Au/n-GaAs and 150-degrees-C for Ti/n-GaAs are suitable temperatures. It is concluded from the analysis of experimental results that only the hydrogen located at or near the metal-semiconductor interface, rather than the hydrogen in the bulk of either the semiconductor or the metal, is responsible for the ZBA/RBA effect on SBH.
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I describe an exploration criterion that attempts to minimize the error of a learner by minimizing its estimated squared bias. I describe experiments with locally-weighted regression on two simple kinematics problems, and observe that this "bias-only" approach outperforms the more common "variance-only" exploration approach, even in the presence of noise.
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