5,994 research outputs found
Non-vacuum Preparation of wse2 Thin Films via the Selenization of Hydrated Tungsten Oxide Prepared using Chemical Solution Methods
It is known that tungsten oxide may be reacted with selenium sources to form WSe2 but literature reports include processing steps that involve high temperatures, reducing atmospheres, and/or oxidative pre-treatments of tungsten oxide. In this work, we report a non-vacuum process for the fabrication of compositionally high quality WSe2 thin films via the selenization of tungsten oxide under milder conditions. Tungsten source materials were various hydrated WO3 and WO2.9 compounds that were prepared using chemical solution techniques. Resulting films were selenized using a two-stage heating profile (250 °C for 15 minutes and 550 °C for 30 minutes) under a static argon atmosphere. Effects of the starting tungsten oxide phase on WSe2 formation after single and double selenization cycles were investigated using Raman spectroscopy and X-ray diffraction (XRD). After two selenization cycles, hydrated WO3 was converted to (002)-oriented WSe2 that exhibits well-resolved peaks for E12g and A1g phonon modes. Only a single selenization cycle was required to convert amorphous WO2.9 to WSe2. All selenizations in this work were achieved in non-reducing atmospheres and at lower temperatures and shorter times than any non-laser-assisted processes reported for WO3-to-WSe2 conversions
Non-vacuum Preparation of wse2 Thin Films via the Selenization of Hydrated Tungsten Oxide Prepared using Chemical Solution Methods
It is known that tungsten oxide may be reacted with selenium sources to form WSe2 but literature reports include processing steps that involve high temperatures, reducing atmospheres, and/or oxidative pre-treatments of tungsten oxide. In this work, we report a non-vacuum process for the fabrication of compositionally high quality WSe2 thin films via the selenization of tungsten oxide under milder conditions. Tungsten source materials were various hydrated WO3 and WO2.9 compounds that were prepared using chemical solution techniques. Resulting films were selenized using a two-stage heating profile (250 oC for 15 minutes and 550 oC for 30 minutes) under a static argon atmosphere. Effects of the starting tungsten oxide phase on WSe2 formation after single and double selenization cycles were investigated using Raman spectroscopy and X-ray diffraction (XRD). After two selenization cycles, hydrated WO3 was converted to (002)-oriented WSe2 that exhibits well-resolved peaks for E12g and A1g phonon modes. Only a single selenization cycle was required to convert amorphous WO2.9 to WSe2. All selenizations in this work were achieved in non-reducing atmospheres and at lower temperatures and shorter times than any non-laser-assisted processes reported for WO3-to-WSe2 conversions
Ultra-compact planoconcave zoned metallic lens based on the fishnet metamaterial
The following article appeared Pacheco-Pena, V., Orazbayev, B., Torres, V., Beruete, M., & Navarro-Cia, M. (n.d). Ultra-compact planoconcave zoned metallic lens based on the fishnet metamaterial. Applied Physics Letters, 103(18), and may be found at http://dx.doi.org/10.1063/1.4827876.A 1.5Îť0 -thick planoconcave zoned lens based on the fishnet metamaterial is demonstrated experimentally at millimeter wavelengths. The zoning technique applied allows a volume reduction of 60% compared to a full fishnet metamaterial lens without any deterioration in performance. The structure is designed to exhibit an effective refractive index n = -0.25 at f = 56.7GHz (Îť0 = 5.29 mm) with a focal length FL = 47.62 mm = 9Îť0. The experimental enhancement achieved is 11.1dB, which is in good agreement with simulation and also with previous full fishnet metamaterial lenses and opens the door for integrated solutions.This work was supported in part by the Spanish
Government under contract Consolider Engineering
Metamaterials CSD2008-00066 and contract TEC2011-
28664-C02-01. V.P.-P. was sponsored by Spanish Ministerio
de Educacion, Cultura y Deporte under Grant No. FPU AP-
2012-3796. B.O. was sponsored by Spanish Ministerio de
EconomÄąa y Competitividad under Grant No. FPI BES-2012-
054909. V.T. is sponsored by the Universidad Publica de
Navarra. M.B. is sponsored by the Spanish Government via
RYC-2011-08221. M.N.-C. was supported by the Imperial
College Junior Research Fellowship
HEP Applications Evaluation of the EDG Testbed and Middleware
Workpackage 8 of the European Datagrid project was formed in January 2001
with representatives from the four LHC experiments, and with experiment
independent people from five of the six main EDG partners. In September 2002
WP8 was strengthened by the addition of effort from BaBar and D0. The original
mandate of WP8 was, following the definition of short- and long-term
requirements, to port experiment software to the EDG middleware and testbed
environment. A major additional activity has been testing the basic
functionality and performance of this environment. This paper reviews
experiences and evaluations in the areas of job submission, data management,
mass storage handling, information systems and monitoring. It also comments on
the problems of remote debugging, the portability of code, and scaling problems
with increasing numbers of jobs, sites and nodes. Reference is made to the
pioneeering work of Atlas and CMS in integrating the use of the EDG Testbed
into their data challenges. A forward look is made to essential software
developments within EDG and to the necessary cooperation between EDG and LCG
for the LCG prototype due in mid 2003.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
Conference (CHEP03), La Jolla, CA, USA, March 2003, 7 pages. PSN THCT00
A Nightingale-Based Model for Dementia Care and its Relevance for Korean Nursing
This article addresses the synchrony between a Western middle-range theory of care for persons with dementia and traditional Korean nursing care. The Western theory is called a need-driven, dementia-compromised behavior model and is heavily influenced by the assessment categories outlined in Nightingaleâs work. This model is presented as congruent with Nightingaleâs work and then viewed from the perspective of traditional Korean nursing. Several congruencies and a few incongruencies are found between these Western and Eastern views, and suggestions are made for greater consistency between these views.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68880/2/10.1177_08943189922107043.pd
Occupational therapy practice education: A perspective from international students in the UK.
Background: Numbers of international students enrolling on occupational therapy (OT) courses in Western institutions have increased. Previous examination of these students' experience of practice education is limited. Objective: To explore the opportunities and challenges experienced by international students in OT practice education. Methods: This study adopted a phenomenological approach, recruiting six individuals from three UK universities. Data from semi-structured interviews was given thematic analysis for result interpretation. Results: Participants identified learning OT in the workplace, working in a multidisciplinary team and personal and professional development as practice education opportunities. Language difficulties, differences in communication styles, multiple cultural differences and unfamiliarity with the National Health Service (NHS) were the main challenges. Good practice educators and supportive team members were the main contributors to positive placement experiences. Conclusions: Participants gained knowledge and skills from practice education that existing healthcare literature suggests they are expected to attain. Several challenges were highlighted regarding participation in practice education. The findings reveal a need to enhance practice educators' skills in supervising international students. Universities are recommended to invest time and resources in supporting the learning needs of these students. Significance: The first study to present international students views on OT pre-registration practice placements in the UK
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
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