Determination of Density of Trap States at Y\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e-Stabilized ZrO\u3csub\u3e2\u3c/sub\u3e/Si Interface of Yba\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e7-δ\u3c/sub\u3e/Y\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e-Stabilized ZrO\u3csub\u3e2\u3c/sub\u3e/Si Capacitors

Yba2Cu3O7-δ/yttria‐stabilized zirconia (YSZ)/silicon superconductor‐insulator‐semiconductor capacitors are characterized with current‐voltage and capacitance‐voltage (C‐V) measurements at different temperatures between 223 and 80 K. As a result of ‘‘freezing’’ of mobile ions in YSZ, effects of trapped charge at the YSZ/Si interface dominate the device electrical properties at superconducting temperatures. Density of interface states and its temperature dependence are determined using a modified high frequency C‐V method, in which the temperature dependences of band gap, Fermi level, and active dopant and intrinsic carrier concentrations are considered. At superconducting temperatures, e.g., 80 K, the interface state density within the band gap is reduced to lower than 1×1011 cm−2 eV at midgap. The low interface state density at the YSZ/Si interface is important for acceptable performance and reliability devices made up of such capacitors

Donor complex formation due to a high-dose Ge implant into Si

To investigate boron deactivation and/or donor complex formation due to a high‐dose Ge and C implantation and the subsequent solid phase epitaxy, SiGe and SiGeC layers were fabricated and characterized. Cross‐sectional transmission electron microscopy indicated that the SiGe layer with a peak Ge concentration of 5 at. % was strained; whereas, for higher concentrations, stacking faults were observed from the surface to the projected range of the Ge as a result of strain relaxation. Photoluminescence (PL) results were found to be consistent with dopant deactivation due to Ge implantation and the subsequent solid phase epitaxial growth of the amorphous layer. Furthermore, for unstrained SiGe layers (Ge peak concentration ≥7 at. %), the PL results support our previously proposed donor complex formation. These findings were confirmed by spreading resistance profiling. A model for donor complex formation is proposed

Thermally Activated Reversible Threshold Shifts in Yba\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e7-δ\u3c/sub\u3e/Yttria-Stabilized Zirconia/Si Capacitors

Yba2Cu3O7-δ/yttria‐stabilized zirconia (YSZ)/silicon superconductor–insulator–semiconductor capacitors are characterized with capacitance‐voltage (C‐V) measurements at different gate‐voltage sweep rates and under bias‐temperature cycling. It is shown that ionic conduction in YSZ causes both hysteresis and stretch‐out in room‐temperature C‐V curves. A thermally activated process with an activation energy of about 39 meV in YSZ and/or at YSZ/Si interface is attributed to trapping/detrapping mechanisms in the SiOx interfacial layer between YSZ and Si. The negative mobile ions in YSZ can be moved by an applied electric field at room temperature and then ‘‘frozen’’ with decreasing temperature, giving rise to adjustable threshold voltages at low temperatures

Scanning tunneling microscopy study of the possible topological surface states in BiTeCl

Recently, the non-centrosymmetric bismuth tellurohalides such as BiTeCl are being studied as possible candidates of topological insulators. While some photoemission studies showed that BiTeCl is an inversion asymmetric topological insulator, others showed that it is a normal semiconductor with Rashba splitting. Meanwhile, first-principle calculationsfailed to confirm the existence of topological surface states in BiTeCl so far. Therefore, the topological nature of BiTeCl requires further investigation. Here we report low temperature scanning tunneling microscopy study on the surface states of BiTeCl single crystals. On the tellurium-terminated surfaces with low defect density, strong evidences for topological surface states are found in the quasi-particle interference patterns generated by the scattering of these states, both in the anisotropy of the scattering vectors and the fast decay of the interference near step edges. Meanwhile, on samples with much higher defect densities, we observed surface states that behave differently. Our results help to resolve the current controversy on the topological nature of BiTeCl.Comment: 13pages,4figure

Virtualization for Distributed Ledger Technology (vDLT)

Recently, with the tremendous development of crypto-currencies, distributed ledger technology (DLT) (e.g., blockchain) has attracted significant attention. The traditional Internet was originally design to to handle the exchange of information. With DLT, we will have the Internet of value. Although DLT has great potential to create new foundations for our economic and social systems, the existing DLT has a number of drawbacks (e.g., scalability) that prevent it from being used as a generic platform for distributed

Distinguishing Emission-Associated Ambient Air PM2.5 Concentrations and Meteorological Factor-Induced Fluctuations

Although PM2.5 (particulate matter with aerodynamic diameters less than 2.5 μm) in the air originates from emissions, its concentrations are often affected by confounding meteorological effects. Therefore, direct comparisons of PM2.5 concentrations made across two periods, which are commonly used by environmental protection administrations to measure the effectiveness of mitigation efforts, can be misleading. Here, we developed a two-step method to distinguish the significance of emissions and meteorological factors and assess the effectiveness of emission mitigation efforts. We modeled ambient PM2.5 concentrations from 1980 to 2014 based on three conditional scenarios: realistic conditions, fixed emissions, and fixed meteorology. The differences found between the model outputs were analyzed to quantify the relative contributions of emissions and meteorological factors. Emission-related gridded PM2.5 concentrations excluding the meteorological effects were predicted using multivariate regression models, whereas meteorological confounding effects on PM2.5 fluctuations were characterized by probabilistic functions. When the regression models and probabilistic functions were combined, fluctuations in the PM2.5 concentrations induced by emissions and meteorological factors were quantified for all model grid cells and regions. The method was then applied to assess the historical and future trends of PM2.5 concentrations and potential fluctuations on global, national, and city scales. The proposed method may thus be used to assess the effectiveness of mitigation actions

The number of CD56^dim NK cells in the graft has a major impact on risk of disease relapse following allo-HSCT

Key Points A stem cell graft NK cell dose below 6.3 × 106 cells per kg associates with risk of disease relapse following T-cell–depleted allo-HSCT. Clinical outcomes of patients undergoing allo-HSCT may be improved by setting an NK cell threshold within donor stem cell grafts.</jats:p

GAPS-megacities: A new global platform for investigating persistent organic pollutants and chemicals of emerging concern in urban air

A pilot study was initiated in 2018 under the Global Atmospheric Passive Sampling (GAPS) Network named GAPS-Megacities. This study included 20 megacities/major cities across the globe with the goal of better understanding and comparing ambient air levels of persistent organic pollutants and other chemicals of emerging concern, to which humans residing in large cities are exposed. The first results from the initial period of sampling are reported for 19 cities for several classes of flame retardants (FRs) including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and halogenated flame retardants (HFRs) including new flame retardants (NFRs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD). The two cities, New York (USA) and London (UK) stood out with ∼3.5 to 30 times higher total FR concentrations as compared to other major cities, with total concentrations of OPEs of 15,100 and 14,100 pg/m3, respectively. Atmospheric concentrations of OPEs significantly dominated the FR profile at all sites, with total concentrations in air that were 2-5 orders of magnitude higher compared to other targeted chemical classes. A moderately strong and significant correlation (r = 0.625, p < 0.001) was observed for Gross Domestic Product index of the cities with total OPEs levels. Although large differences in FR levels were observed between some cities, when averaged across the five United Nations regions, the FR classes were more evenly distributed and varied by less than a factor of five. Results for Toronto, which is a "reference city" for this study, agreed well with a more in-depth investigation of the level of FRs over different seasons and across eight sites representing different urban source sectors (e.g. traffic, industrial, residential and background). Future sampling periods under this project will investigate trace metals and other contaminant classes, linkages to toxicology, non-targeted analysis, and eventually temporal trends. The study provides a unique urban platform for evaluating global exposome.Fil: Saini, Amandeep. Environment and Climate Change; CanadáFil: Harner, Tom. Environment and Climate Change; CanadáFil: Chinnadhurai, Sita. Environment and Climate Change; CanadáFil: Schuster, Jasmin K.. Environment and Climate Change; CanadáFil: Yates, Alan. Environment and Climate Change; CanadáFil: Sweetman, Andrew. Lancaster Environment Centre; Reino UnidoFil: Aristizabal Zuluaga, Beatriz H.. Universidad Nacional de Colombia; ColombiaFil: Jiménez, Begoña. Consejo Superior de Investigaciones Científicas; EspañaFil: Manzano, Carlos A.. Universidad de Chile; ChileFil: Gaga, Eftade O.. Eskisehir Technical University; TurquíaFil: Stevenson, Gavin. National Measurement Institute; AustraliaFil: Falandysz, Jerzy. Uniwersytet Gdanski; PoloniaFil: Ma, Jianmin. Peking University; ChinaFil: Miglioranza, Karina Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Kannan, Kurunthachalam. Nyu Grossman School Of Medicine; Estados UnidosFil: Tominaga, Maria. Sao Paulo State Environmental Company; BrasilFil: Jariyasopit, Narumol. No especifíca;Fil: Rojas, Nestor Y.. Universidad Nacional de Colombia; ColombiaFil: Amador-Muñoz, Omar. Universidad Nacional Autónoma de México; MéxicoFil: Sinha, Ravindra. Patna University; IndiaFil: Alani, Rose. University of Lagos; NigeriaFil: Suresh, R.. No especifíca;Fil: Nishino, Takahiro. Tokyo Metropolitan Research Institute for Environmental Protection; JapónFil: Shoeib, Tamer. American University In Cairo; Egipt