4,143 research outputs found
Discovery of halloysite books in a ~270,000 year-old buried tephra deposit in northern New Zealand
No full textAs part of a wider study examining the geomechanical properties, especially sensitivity, of sequences of Quaternary pyroclastic and associated deposits and buried soils in the landslide-prone western Bay of Plenty area near Tauranga, eastern North Island, we examined the mineralogy of a pale pinkish-grey tephra deposit directly beneath non-welded, siliceous Te Ranga Ignimbrite (~2 m thick) in a ~25 m high cutting at Tauriko.http://www.smectech.com.au/ACMS/ACMS_Conferences/ACMS21/ACMS%202010%20Abstracts/ACMS%202010%20S1A6_Wyatt%20et%20al%20(Lowe).pd
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Policy impact of access to rural mental health care services : a legislative analysis of TX SB 633
No full textThis professional report examined rural mental health care access in Texas based on a scientific literature review and analysis of SB 633. A legislative history of SB 633 will provide insights on how the state operationalized rural mental health access within an existing policy context. This policy context was influenced by the stakeholders who have been engaging with the state. Collaboration between mental health providers is a central strategy of the SB 633 process to increase rural mental health access and will be described in detail. When examined within the policyscape framework, this writer analysis finds collaboration to be a low-cost and highly effective form of policy maintenance. SB 633 uses cost savings and quality of service to measure the degree to which expanding services improved mental health access. This writer believes that cost savings are easy to understand but miss vital aspects of access to mental health care. This writer finds that Texas Statewide Behavioral Health Strategic plan and the NASW Code of Ethics better assess quality mental health access. This writer believes that both cost and these quality measures should be used to improve mental health accessPublic AffairsSocial Wor
Selective-Area MOCVD Growth and Carrier-Transport-Type Control of InAs(Sb)/GaSb Core-Shell Nanowires
No full textWe
report the first selective-area growth of high quality InAs(Sb)/GaSb
core–shell nanowires on Si substrates using metal–organic
chemical vapor deposition (MOCVD) without foreign catalysts. Transmission
electron microscopy (TEM) analysis reveals that the overgrowth of
the GaSb shell is highly uniform and coherent with the InAs(Sb) core
without any misfit dislocations. To control the structural properties
and reduce the planar defect density in the self-catalyzed InAs core
nanowires, a trace amount of Sb was introduced during their growth.
As the Sb content increases from 0 to 9.4%, the crystal structure
of the nanowires changes from a mixed wurtzite (WZ)/zinc-blende (ZB)
structure to a perfect ZB phase. Electrical measurements reveal that
both the n-type InAsSb core and p-type GaSb shell can work as active
carrier transport channels, and the transport type of core–shell
nanowires can be tuned by the GaSb shell thickness and back-gate voltage.
This study furthers our understanding of the Sb-induced crystal-phase
control of nanowires. Furthermore, the high quality InAs(Sb)/GaSb
core–shell nanowire arrays obtained here pave the foundation
for the fabrication of the vertical nanowire-based devices on a large
scale and for the study of fundamental quantum physics
Origin of the low thermal conductivity of the thermoelectric material beta-Zn(4)Sb(3): An ab initio theoretical study
No full textBy modeling beta-Zn(4)Sb(3) material as a Zn(36)Sb(30) crystal with defects, the crystal structure and thermal properties of beta-Zn(4)Sb(3) are studied by ab initio method to explain its extremely low thermal conductivity at moderate temperature. The formation and migration energies of defects are calculated and used to explain the partial occupation of Zn at the lattice sites, the disordered local structures and the origin of the low thermal conductivity of beta-Zn(4)Sb(3). Our study also unravels the puzzling dependence of thermal conductivity on doping in beta-Zn(4)Sb(3). A doping strategy is proposed to improve the thermoelectric performance of beta-Zn(4)Sb(3). (C) 2011 American Institute of Physics. [doi:10.1063/1.3599483
Stability of Sb-Te layered structures: First-principles study
No full textUsing an effective one-dimensional cluster expansion in combination with first-principles electronic structure calculations we have studied the energetics and electronic properties of Sb-Te layered systems. For a Te concentration between 0 and 60 at. % an almost continuous series of metastable structures is obtained consisting of consecutive Sb bilayers next to consecutive Sb2Te3 units, with the general formula (Sb2)n(Sb2Te3)m (n,m=1,2,...). Between 60 and 100 at. % no stable structures are found. We account explicitly for the weak van der Waals bonding between Sb bilayers and Sb2Te3 units by using a recently developed functional, which strongly improves the interlayer bonding distances. At T=0 K, no evidence is found for the existence of two separate single-phase regions ? and ? and a two-phase region ?+?. Metastable compounds with a Te concentration between 0 and 40 at. % are semimetallic, whereas compounds with a Te concentration between 50 and 60 at. % are semiconducting. Compounds with an odd number of Sb layers are metallic and have a much higher formation energy than those with an even number of consecutive Sb layers, thereby favoring the formation of Sb bilayers.Materials Science and EngineeringMechanical, Maritime and Materials Engineerin
Legal and Financial Problems of International Joint Custody of Children
No full textThe aim of this article is to analyze very interesting and currently up-to-date area of children living in international joint custody from the legal and financial point of view. This covers the situation when custody of a child is awarded to both parents living in different states of the European Union (or also other states). The number of marriages contracted between Czech nationals and foreign nationals and also between nationals from two different states (not necessarily inside European Union) increases every year while free movement of people is a real practice today. Because these international marriages are becoming more common they bring new problems that must be solved by contemporary law. This regulation needs to result from the knowledge of the children psychology that is affecting family law the most but also has its practical aspects in the area of taxation and payment issues that will be analyzed deeply as well.juridical problems, financial problems, international joint custody, family.
Nonlinear influence of excess Mn on the magnetoelastic transition in (Mn,Cr)<sub>2</sub>Sb
No full textThe influence of excess Mn on the magnetoelastic ferromagnetic-to-antiferromagnetic transition Tt in the magnetocaloric compound (Mn,Cr)2Sb has been studied. With increasing excess Mn the magnetoelastic transition temperature for (Mn,Cr)2Sb initially increases and then decreases. This trend is accompanied by a strong reduction of the (Mn,Cr)Sb secondary phase. With increasing excess Mn a higher Cr content was found in the (Mn,Cr)Sb secondary phase in comparison to the matrix phase. This competition for Cr leads to a nonlinear dependence of Tt with increasing excess Mn at a fixed nominal Cr content. However, we observed that Tt depends linear on the c/a ratio for a wide range of temperatures from 170 to 350 K. A compositional diagram of the c/a ratio was constructed to assist the selection of (Mn,Cr)2Sb alloys with a desired transition temperature.RST/Fundamental Aspects of Materials and Energ
Fabrication and properties of Sb-doped ZnO thin films grown by radio frequency (RF) magnetron sputtering
No full textSb-doped and undoped ZnO thin films were deposited on Si (100) substrates by radio frequency (RF) magnetron sputtering. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses revealed that all the films had polycrystalline wurtzite structure and c-axis preferred orientation. Room temperature Hall measurements showed that the as-grown films were n-type and conducting (rho similar to 1-10 Omega cm). Annealing in a nitrogen ambient at 400 degrees C for 1 h made both samples highly resistive (rho > 10(3) Omega cm). Increasing the annealing temperature up to 800 C, the resistivity of the ttndoped ZnO film decreased gradually, but it increased for the Sb-doped ZnO film. In the end, the Sb-doped ZnO film annealed at 800 C became semi-insulating with a resistivity of 10(4)Omega cm. In addition, the effects of annealing treatment and Sb-doping on the structural and electrical properties are discussed. (c) 2006 Elsevier B.V. All rights reserved
Homologous series of layered structures in binary and ternary Bi-Sb-Te-Se systems: Ab initio study
No full textIn order to account explicitly for the existence of long-periodic layered structures and the strong structural relaxations in the most common binary and ternary alloys of the Bi-Sb-Te-Se system, we have developed a one-dimensional cluster expansion (CE) based on first-principles electronic structure calculations, which accounts for the Bi and Sb bilayer formation. Excellent interlayer distances are obtained with a van der Waals density functional. It is shown that a CE solely based on pair interactions is sufficient to provide an accurate description of the ground-state energies of Bi-Sb-Te-Se binary and ternary systems without making the data set of ab initio calculated structures unreasonably large. For the binary alloys A1?xQx (A=Sb, Bi; Q=Te, Se), a ternary CE yields an almost continuous series of (meta)stable structures consisting of consecutive A bilayers next to consecutive A2Q3 for 00.6, the binary alloy segregates into pure Q and A2Q3. The Bi-Sb system is described by a quaternary CE and is found to be an ideal solid solution stabilized by entropic effects at T?0 K but with an ordered structure of alternating Bi and Sb layers for x=0.5 at T=0 K. A quintuple CE is used for the ternary Bi-Sb-Te system, where stable ternary layered compounds with an arbitrary stacking of Sb2Te3, Bi2Te3, and Te-Bi-Te-Sb-Te quintuple units are found, optionally separated by mixed Bi/Sb bilayers. Electronic properties of the stable compounds were studied taking spin-orbit coupling into account.Materials Science and EngineeringMechanical, Maritime and Materials Engineerin
Pyrolysis Studies and Deposition of Sb Films Using the Novel Omvpe Source (I-Pr)<sub>2</sub> SbH
No full textABSTRACTThe novel antimony source compound di-isopropylantimony hydride, (i-Pr)2 was synthesized and evaluated for use as a volatile Sb-source compound for low temperature growth of Sb-containing semiconductor materials. (i-Pr)2SbH was pyrolyzed in a horizontal atmospheric pressure organometallic vapor phase epitaxy (OMVPE) reactor using Arand H2 as carrier gases. The gaseous exhaust products were analyzed by a residual gas analyzer. Complete pyrolysis of (i-Pr)2SbH in our OMVPE reactor occursaround 300°C and 350°C in Ar and H2, respectively. A comparison between the pyrolysis temperatures and pyrolysis byproducts with respect to a proposed decomposition mechanism of (i-Pr)2SbH is presented. Sb films were grown on Si(100) andSi(111) as low as 200° C. The Sb films were analyzed by Auger and X-ray diffraction. These polycrystalline Sb films were free of detectable carbon by AES. X-ray diffraction data indicated that these Sb films were highly oriented in the [000L] direction.</jats:p
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