113 research outputs found
Декор ліпного посуду з кургану раннього залізного віку біля с. Івангород на Кіровоградщині
У статті розглядаються особливості декору ліпного посуду з кургану раннього залізного віку біля с. Івангород у системі зв’язків фракійської та ранньоскіфської культур
Diameter-dependent conductance of InAs nanowires
Electrical conductance through InAs nanowires is relevant for electronic
applications as well as for fundamental quantum experiments. Here we employ
nominally undoped, slightly tapered InAs nanowires to study the diameter
dependence of their conductance. Contacting multiple sections of each wire, we
can study the diameter dependence within individual wires without the need to
compare different nanowire batches. At room temperature we find a
diameter-independent conductivity for diameters larger than 40 nm, indicative
of three-dimensional diffusive transport. For smaller diameters, the resistance
increases considerably, in coincidence with a strong suppression of the
mobility. From an analysis of the effective charge carrier density, we find
indications for a surface accumulation layer.Comment: 9 pages, 5 figure
High-Performance InAs Nanowire MOSFETs
In this letter, we present a 15-nm-diameter InAs nanowire MOSFET with excellent on and off characteristics. An n-i-n doping profile was used to reduce the source and drain resistances, and an Al2O3/HfO2 bilayer was introduced in the high-k process. The nanowires exhibit high drive currents, up to 1.25 A/mm, normalized to the nanowire circumference, and current densities up to 34 MA/cm2 (VD = 0.5 V). For a nominal LG = 100 nm, we observe an extrinsic transconductance (gm) of 1.23 S/mm and a subthreshold swing of 93 mV/decade at VD = 10 mV
Doping Incorporation in InAs nanowires characterized by capacitance measurements
Sn and Se doped InAs nanowires are characterized using a capacitance-voltage technique where the threshold voltages of nanowire capacitors with different diameter are determined and analyzed using an improved radial metal-insulator-semiconductor field-effect transistor model. This allows for a separation of doping in the core of the nanowire from the surface charge at the side facets of the nanowire. The data show that the doping level in the InAs nanowire can be controlled on the level between 2×1018 to 1×1019 cm−3, while the surface charge density exceeds 5×1012 cm−2 and is shown to increase with higher dopant precursor molar fraction
Conceptualizing multidimensional barriers: a framework for assessing constraints in realizing recreational benefits of urban green spaces
This article was supported by the German Research Foundation (DFG) and the Open Access Publication Fund of Humboldt-Universität zu Berlin.Although potential urban green space accessibility is being discussed widely, specific barriers that affect accessibility are often under-estimated. They do not equate to limited or uneven accessibility nor are they exclusively related to physical settings. Rather, the range of barriers and their complex interactions, including people’s perceptions, personal conditions, and institutional frameworks, make this topic less clear cut and difficult to put into practice for planning purposes. Given the importance of barriers when people make decisions, we present a conceptual framework to capture the cumulative and interactive effects of different barriers on realizing recreational benefits of urban green spaces. The framework classifies physical, personal, and institutional barriers and highlights their interactions based on three case studies: Stockholm, Leipzig, and Lodz. We argue that constraints to the accessibility of urban green spaces are not so much the interactions between various physical, personal, and institutional barriers, but more the significance that beneficiaries assign to them as perceived barrier effects. Studying barriers seeks to improve the knowledge about the non-use of urban green spaces and to enable us to draw conclusions about the actual accessibility of recreational benefits. Deduced from the conceptual framework, three pathways are contrasted for improving accessibility to the recreational benefits of urban green spaces: the environment, knowledge, and engagement. We argue that these pathways should not be a diffuse objective, but a sensitive and scale-dependent re-balance of individual, physical, and institutional factors for considering justice in environmental and green space planning and management. Our systematic conceptualization and classification of multidimensional barriers enables a more comprehensive understanding of individuals’ decisions in terms of accessing recreational benefits.Peer Reviewe
High modal number and triple trisomies are highly correlated favorable factors in childhood B-cell precursor high hyperdiploid acute lymphoblastic leukemia treated according to the NOPHO ALL 1992/2000 protocols.
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This article is open access.Between 1992 and 2008, 713 high hyperdiploid acute lymphoblastic leukemias in children aged 1-15 years were diagnosed and treated according to the Nordic Society for Pediatric Hematology and Oncology acute lymphoblastic leukemia 1992/2000 protocols. Twenty (2.8%) harbored t(1;19), t(9;22), der(11q23), or t(12;21). The median age of patients with "classic" high hyperdiploidy was lower than that of patients with translocation-positive high hyperdiploidy (P53/55 (P=0.020/0.024). In multivariate analyses, modal number and triple trisomies were significantly associated with superior event-free survival in separate analyses with age and white blood cell counts. When including both modal numbers and triple trisomies, only low white blood cell counts were significantly associated with superior event-free survival (P=0.009). We conclude that high modal chromosome numbers and triple trisomies are highly correlated prognostic factors and that these two parameters identify the same subgroup of patients characterized by a particularly favorable outcome.Swedish Childhood Cancer Foundation
Swedish Cancer Society
Swedish Research Counci
Twinning superlattices in indium phosphide nanowires
Here, we show that we control the crystal structure of indium phosphide (InP)
nanowires by impurity dopants. We have found that zinc decreases the activation
barrier for 2D nucleation growth of zinc-blende InP and therefore promotes the
InP nanowires to crystallise in the zinc blende, instead of the commonly found
wurtzite crystal structure. More importantly, we demonstrate that we can, by
controlling the crystal structure, induce twinning superlattices with
long-range order in InP nanowires. We can tune the spacing of the superlattices
by the wire diameter and the zinc concentration and present a model based on
the cross-sectional shape of the zinc-blende InP nanowires to quantitatively
explain the formation of the periodic twinning.Comment: 18 pages, 4 figure
From InSb Nanowires to Nanocubes: Looking for the Sweet Spot
High aspect ratios are highly desired to fully exploit the one-dimensional properties of indium antimonide nanowires. Here we systematically investigate the growth mechanisms and find parameters leading to long and thin nanowires. Variation of the V/III ratio and the nanowire density are found to have the same influence on the “local” growth conditions and can control the InSb shape from thin nanowires to nanocubes. We propose that the V/III ratio controls the droplet composition and the radial growth rate and these parameters determine the nanowire shape. A sweet spot is found for nanowire interdistances around 500 nm leading to aspect ratios up to 35. High electron mobilities up to 3.5 × 10^4 cm^2 V^(–1) s^(–1) enable the realization of complex spintronic and topological devices
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