Control of the current profile is a crucial issue for improved confinement and the inhibition of instability in advanced tokamak operation. Using typical discharge data for the Experimental Advanced ...Superconducting Tokamak, numerical simulations of driven-current profile control in mode conversion current drive (MCCD) in the ion cyclotron range of frequencies were performed employing a full-wave method and Ehst–Karney efficiency formula. Results indicate that the driven current profile in MCCD can be effectively modified by shifting the mode conversion layer. The peak of the driven current can be located at an aimed position in the normalized minor radius range (−0.60≤r/a≤0) by changing the radiofrequency and the minority-ion concentration. The efficiency of the off-axis MCCD can reach 233 kA/MW through optimization, and the mode converted ion cyclotron wave plays an important role in such scenarios. The effects of electron temperature and plasma density on the driven current profile are also investigated.
Doping modifies the electronic, optical, and catalytic behavior of materials through the newly formed chemical bonds and the localized electrons. With the aid of first-principles calculations, the ...electronic, optical, and catalytic performances of the nonmetal (NM = H, B, C, N, O, F, Si, P, S, Cl, As, Br, Te, or I)-doped monolayer WSe2 were investigated. The results showed that the NM dopants substitute preferentially for Se under a W-rich condition and H, F, Cl, Br, and I atoms are willing to locate at the interstitial site. The electron-clouds around the dopants and nearby W or Se atoms were altered by the newly formed W-NM or Se-NM bonds, with the differences determined by the bonding strength between them. The band gap, optical absorption edge, and intensities were altered or shifted by less than 0.08 eV, 32 nm, and 9.5%, respectively. The H, F, P, Cl, As, Br, and I dopants were conductive to separating the photogenerated e-/h+ pairs, whereas the B, C, Si, and Te dopants became recombination centers for the photogenerated e-/h+ pairs. Compared with pristine monolayer WSe2, NM atoms with odd free electrons reduced the reduction potential by 0.39-0.71 eV and enhanced the oxidation potential by 0.45-0.75 eV. Thus, we can adjust the redox potentials of monolayer WSe2 by introducing different kinds of NM impurities for various catalytic reactions, and the H-, F-, P-, Cl-, As-, Br-, and I-doped specimens have excellent photocatalysis capability.
We demonstrate a novel form of thermally-assisted hysteresis in the transfer curves of monolayer MoS
FETs, characterized by the appearance of a large gate-voltage window and distinct current levels ...that differ by a factor of ∼10
. The hysteresis emerges for temperatures in excess of 400 K and, from studies in which the gate-voltage sweep parameters are varied, appears to be related to charge injection into the SiO
gate dielectric. The thermally-assisted memory is strongly suppressed in equivalent measurements performed on bilayer transistors, suggesting that weak screening in the monolayer system plays a vital role in generating its strongly sensitive response to the charge-injection process. By exploiting the full features of the hysteretic transfer curves, programmable memory operation is demonstrated. The essential principles demonstrated here point the way to a new class of thermally assisted memories based on atomically thin two-dimensional semiconductors.
This paper puts forward a Bayesian method for multiple gross errors location and estimation, and studies the masking and swamping problem in multiple gross errors detection from a new point of view, ...further proposes the corresponding feasible solution. First, the Bayesian method for gross error location is established based on the posterior probabilities of classification variables, each of which is used to determine whether each observation contains gross error or not. When some interactions exist among observations with multiple gross errors, the above-mentioned method may lead to the failure of detection due to masking and swamping. For that, on the basis of analyzing the character of masking and swamping, starting from the eigen structure of the sample correlation coefficient matrix of the classification vector, we give the Bayesian unmasking method to locate multiple gross errors, and design the corresponding algorithm, namely the adaptive Gibbs sampling algorithm. Finally, applying the mean shift model, we raise a Bayesian approach to estimate gross errors. Significant applications of the approach show the promising results on overcoming masking and swamping.
Pancreatic beta-cell is responsible for insulin secretion in response to the availability of nutrients. Type 2 diabetes mellitus (T2D) is the result of pancreatic b-cell failure to supply sufficient ...amount of insulin accompanied with decreased sensitivity of the body tissues to respond to insulin. The insulin secretion apparatus of beta-cell is uniquely equipped with multiple metabolic and signaling steps that are under rigorous control. The metabolic machinery of beta-cell is designed to sense the fluctuations in blood glucose level and supply insulin accordingly to the needs of body. Besides glucose, amino acids including glutamine and leucine and also fatty acids are known to either stimulate the beta-cell directly or potentiate the glucose stimulated insulin secretion (GSIS) response. Glucose metabolism dependent GSIS is linked with the production of ATP that is needed for K+ATP channel inhibition and influx of calcium, necessary for insulin granule exocytosis. Besides glucose metabolism, amino acid metabolism and lipid metabolism derived metabolites mediate the optimal glucose response of beta-cells to secrete insulin. Metabolites derived from nutrient secretagogues that directly or indirectly participate in the enhancement of GSIS are considered as metabolic coupling factors. In this review, we will discuss the regulation of insulin secretion by b-cell keeping the recent developments in metabolic signaling in focus. The relevant metabolic pathways in pancreatic beta-cell and their role in the control of fuel-stimulated insulin secretion will be reviewed to arrive at a consensus picture with respect to the metabolic signaling of insulin secretion.
The objective of this study is to demonstrate the feasibility of acquiring geothermal energy using abandoned oil and gas wells. The equations of fluid flow and heat exchange were developed and solved ...by numerical methods. Computational results indicated that the two main factors of influencing heat exchange and output power were fluid flow rate and geothermal gradient. The net output power is 59.41 kW at a geothermal gradient of 45°C/km and flow rate of 0.04 m/s. The fluid outlet temperature after 10 years of operation is just 0.41°C lower than that of initial time.
8-Isoprostane, a ROS-derived prostanoid that acts via the thromboxane receptor (TP), is implicated in neonatal pulmonary hypertension. The purpose of this study was to examine the effect of hypoxia ...on vascular smooth muscle ROS generation, 8-isoprostane activity, and TP binding. First-passage neonatal porcine pulmonary artery myocytes were exposed to 10% O
2 (hypoxic myocytes; HM) or 21% O
2 (normoxic myocytes) for 72 h. Hypoxia increased in vitro generation of ROS, superoxide, and 8-isoprostane. ROS generation was ablated by inhibition of mitochondrial complex III. SOD1 and 3 activities were increased, but SOD2 activity decreased by 45% in HM. 8-Isoprostane generation was driven by the addition of peroxide and nitric oxide; incubation with permeative PEG–SOD, but not PEG–catalase or impermeative SOD, attenuated hypoxia-induced 8-isoprostane generation. 8-Isoprostane affinity for TP was markedly increased in HM. Myocyte 8-isoprostane challenge caused TP internalization and calcium release only in HM; this was sensitive to TP blockade and was normalized by activation of adenylyl cyclase. We propose that hypoxia induces superoxide accumulation in pulmonary artery myocytes through inhibition of mitochondrial SOD2 activity, promoting peroxynitrite-induced generation of 8-isoprostane. 8-Isoprostane binds to sensitized TP receptors, causing receptor internalization and signaling to calcium release in hypoxic myocytes. 8-Isoprostane may be an important pulmonary vasoconstrictor during neonatal hypoxia.
PDF
