745 research outputs found
Temperature dependent transport in suspended graphene
The resistivity of ultra-clean suspended graphene is strongly temperature
dependent for 5K<T<240K. At T~5K transport is near-ballistic in a device of
~2um dimension and a mobility ~170,000 cm^2/Vs. At large carrier density,
n>0.5*10^11 cm^-2, the resistivity increases with increasing T and is linear
above 50K, suggesting carrier scattering from acoustic phonons. At T=240K the
mobility is ~120,000 cm^2/Vs, higher than in any known semiconductor. At the
charge neutral point we observe a non-universal conductivity that decreases
with decreasing T, consistent with a density inhomogeneity <10^8 cm^-2
Conductivity of graphene: How to distinguish between samples with short and long range scatterers
Applying a quasiclassical equation to carriers in graphene we found a way how
to distinguish between samples with the domination of short and long range
scatterers from the conductivity measurements. The model proposed explains
recent transport experiments with chemically doped as well as suspended
graphene.Comment: 6 pages, 3 figures, some references have been corrected and revise
A journey to client and therapist mutuality in person-centered psychotherapy: a case study
This aim of this case study was to build theory on the development of clientātherapist mutuality in person-centered psychotherapy. A case study focusing on a 42-year-old female client who had presented for therapy following trauma within interpersonal relationships has been used. A reflective, theory-building, case study method was adopted that used data gathered from verbatim session notes and research interviews between the therapist (first author) and research supervisor (second author). Three primary therapeutic processes that contributed to the development of mutuality are discussed. First, the development of mutual empathy in the relationship; second, strategies for disconnection and staying out of relationship are identified. Third, client agency and mutuality is explored. In conclusion the study proposes that mutuality is a key construct within person-centered psychotherapy and develops as a natural consequence of the presence of Rogersā therapeutic conditions
Superconductivity coexisting with phase-separated static magnetic order in (Ba,K)FeAs, (Sr,Na)FeAs and CaFeAs
The recent discovery and subsequent developments of FeAs-based
superconductors have presented novel challenges and opportunities in the quest
for superconducting mechanisms in correlated-electron systems. Central issues
of ongoing studies include interplay between superconductivity and magnetism as
well as the nature of the pairing symmetry reflected in the superconducting
energy gap. In the cuprate and RE(O,F)FeAs (RE = rare earth) systems, the
superconducting phase appears without being accompanied by static magnetic
order, except for narrow phase-separated regions at the border of phase
boundaries. By muon spin relaxation measurements on single crystal specimens,
here we show that superconductivity in the AFeAs (A = Ca,Ba,Sr)
systems, in both the cases of composition and pressure tunings, coexists with a
strong static magnetic order in a partial volume fraction. The superfluid
response from the remaining paramagnetic volume fraction of
(BaK)FeAs exhibits a nearly linear variation in T
at low temperatures, suggesting an anisotropic energy gap with line nodes
and/or multi-gap effects.Comment: 14 pages 7 figures (4 for main text and 3 for on-line supplementary
documents
Synthesis and Structural Investigation of an \u27Oxazinoquinolinespirohexadienone\u27 That Only Exists as Its Long-Wavelength Ring-Opened Quinonimine Isomer
The spirocyclic oxazinoquinolinespirohexadienone (OSHD) photochromes are computationally predicted to be an attractive target as electron deficient analogues of the perimidinespirohexadienone (PSHD) photochromes, for eventual application as photochromic photooxidants. We have found the literature method for their preparation unsuitable and present an alternative synthesis. Unfortunately the product of this synthesis is the long wavelength (LW) ring-opened quinonimine isomer of the OSHD. We have found this isomer does not close to the spirocyclic short wavelength isomer (SW) upon prolonged standing in the dark, unlike other PSHD photochromes. The structure of this long wavelength isomer was found by NMR and X-ray crystallography to be exclusively the quinolinone (keto) tautomer, though experimental cyclic voltammetry supported by our computational methodology indicates that the quinolinol (enol) tautomer (not detected by other means) may be accessible through a fast equilibrium lying far toward the keto tautomer. Computations also support the relative stability order of keto LW over enol LW over SW
Am I just not good enough? The creation, development and questioning of a high performance coaching identity
While the career experiences and trajectories of various sports workers have received increased scholarly attention, those of professional coaches have, in comparison, received scant consideration. This paper focuses on the career experiences of Maeve (a pseudonym), a high performance coach, and the critical incidents related to the creation, development, and, ultimately, questioning of her professional identity. Data were collected through a series of narrative-biographical interviews and were subject to a process of iterative data analysis. The results indicated that her significant investment into her coaching self, combined with the vagaries and uncertain nature of work in high performance coaching, led her to experience a biographical disruption that interrupted the narrative coherence of her coaching life. The findings add further credence to recent critiques of only understanding and representing coaching careers in a linear and chronically staged fashion
Vibrational Enhancement of the Effective Donor - Acceptor Coupling
The paper deals with a simple three sites model for charge transfer phenomena
in an one-dimensional donor (D) - bridge (B) - acceptor (A) system coupled with
vibrational dynamics of the B site. It is found that in a certain range of
parameters the vibrational coupling leads to an enhancement of the effective
donor - acceptor electronic coupling as a result of the formation of the
polaron on the B site. This enhancement of the charge transfer efficiency is
maximum at the resonance, where the effective energy of the fluctuating B site
coincides with the donor (acceptor) energy.Comment: 5 pages, 3 figure
Career orientations and career cultures : individual and organisational approaches to beginning teachersā careers
Despite the very large literature on teacher careers from an individual perspective, there is relatively little that links the perspectives of teachers themselves to how schools as organisations approach careers. The aim of this paper is, first, to outline how teachersā orientations towards careers change across three dimensions, and, second, to examine how schools as organisations deal with career, developing a model of organisational responses, including developing a concept of ācareer cultureā, derived from an analysis of interviews regarding the first three years of teaching conducted with senior leaders and second year teachers themselves. By considering the fit between individualsā career orientations and school career cultures, the paper surfaces both the fluid nature of these orientations and the subsequent potential instability of the fit
'It would be easier if sheād diedā: young people with parents with dementia articulating inadmissible stories
In the U.K. context where the emphasis is (quite rightly) on living well with dementia, on positivity and enabling
approaches, it can be difficult for researchers to investigate and report negative experiences. Failing to re-present
perceptions and experiences as they are lived, however, does a serious disservice to the research endeavor and can
prevent policy and service development and positive change. In this article, we present some stories told by participants
in an Alzheimerās Society (United Kingdom) Funded project uniquely investigating the perceptions and experiences of
children and young people who have a parent with dementia. Sometimes the stories were not easy to hear, especially
when they challenged dominant master narratives around dementia. We discuss our view that when the young people
we spoke with told us how things were for them, we were ethically bound to respect and disseminate their accounts
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