33,990 research outputs found
Field Effect Transistors on Rubrene Single Crystals with Parylene Gate Insulator
We report on fabrication and characterization of the organic field effect
transistors (OFETs) on the surface of single crystals of rubrene. The parylene
polymer film has been used as the gate insulator. At room temperature, these
OFETs exhibit the p-type conductivity with the field effect mobility up to 1
cm^2/Vs and the on/off ratio ~ 10^4. The temperature dependence of the mobility
is discussed.Comment: 3 page
Kink-antikink interactions in the double sine-Gordon equation and the problem of resonance frequencies
We studied the kink-antikink collision process for the "double sine-Gordon"
(DSG) equation in 1+1 dimensions at different values of the potential parameter
. For small values of we discuss the problem of resonance frequencies.
We give qualitative explanation of the frequency shift in comparison with the
frequency of the discrete level in the potential well of isolated kink. We show
that in this region of the parameter the effective long-range interaction
between kink and antikink takes place.Comment: 9 pages, LaTeX, 4 figures (eps
Question design in nurse-led and GP-led telephone triage for same-day appointment requests: a comparative investigation
Objective: To compare doctors’ and nurses’ communication with patients in primary care telephone triage consultations. Design: Qualitative comparative study of content and form of questions in 51 telephone triage encounters between practitioners (general practitioners (GPs)=29; nurses=22) and patients requesting a same-day appointment in primary care. Audio-recordings of nurse-led calls were synchronised with video recordings of nurse's use of computer decision support software (CDSS) during triage. Setting: 2 GP practices in Devon and Warwickshire, UK. Participants: 4 GPs and 29 patients; and 4 nurses and 22 patients requesting a same-day face-to-face appointment with a GP. Main outcome measure: Form and content of practitioner-initiated questions and patient responses during clinical assessment. Results: A total of 484 question–response sequences were coded (160 GP; 324 N). Despite average call lengths being similar (GP=4 min, 37 s, (SD=1 min, 26 s); N=4 min, 39 s, (SD=2 min, 22 s)), GPs and nurses differed in the average number (GP=5.51, (SD=4.66); N=14.72, (SD=6.42)), content and form of questions asked. A higher frequency of questioning in nurse-led triage was found to be due to nurses’ use of CDSS to guide telephone triage. 89% of nurse questions were oriented to asking patients about their reported symptoms or to wider-information gathering, compared to 54% of GP questions. 43% of GP questions involved eliciting patient concerns or expectations, and obtaining details of medical history, compared to 11% of nurse questions. Nurses using CDSS frequently delivered questions designed as declarative statements requesting confirmation and which typically preferred a ‘no problem’ response. In contrast, GPs asked a higher proportion of interrogative questions designed to request information. Conclusions: Nurses and GPs emphasise different aspects of the clinical assessment process during telephone triage. These different styles of triage have implications for the type of information available following nurse-led or doctor-led triage, and for how patients experience triage
Existence of multi-site intrinsic localized modes in one-dimensional Debye crystals
The existence of highly localized multi-site oscillatory structures (discrete
multibreathers) in a nonlinear Klein-Gordon chain which is characterized by an
inverse dispersion law is proven and their linear stability is investigated.
The results are applied in the description of vertical (transverse, off-plane)
dust grain motion in dusty plasma crystals, by taking into account the lattice
discreteness and the sheath electric and/or magnetic field nonlinearity.
Explicit values from experimental plasma discharge experiments are considered.
The possibility for the occurrence of multibreathers associated with vertical
charged dust grain motion in strongly-coupled dusty plasmas (dust crystals) is
thus established. From a fundamental point of view, this study aims at
providing a first rigorous investigation of the existence of intrinsic
localized modes in Debye crystals and/or dusty plasma crystals and, in fact,
suggesting those lattices as model systems for the study of fundamental crystal
properties.Comment: 12 pages, 8 figures, revtex forma
An extended scaling analysis of the S=1/2 Ising ferromagnet on the simple cubic lattice
It is often assumed that for treating numerical (or experimental) data on
continuous transitions the formal analysis derived from the Renormalization
Group Theory can only be applied over a narrow temperature range, the "critical
region"; outside this region correction terms proliferate rendering attempts to
apply the formalism hopeless. This pessimistic conclusion follows largely from
a choice of scaling variables and scaling expressions which is traditional but
which is very inefficient for data covering wide temperature ranges. An
alternative "extended caling" approach can be made where the choice of scaling
variables and scaling expressions is rationalized in the light of well
established high temperature series expansion developments. We present the
extended scaling approach in detail, and outline the numerical technique used
to study the 3d Ising model. After a discussion of the exact expressions for
the historic 1d Ising spin chain model as an illustration, an exhaustive
analysis of high quality numerical data on the canonical simple cubic lattice
3d Ising model is given. It is shown that in both models, with appropriate
scaling variables and scaling expressions (in which leading correction terms
are taken into account where necessary), critical behavior extends from Tc up
to infinite temperature.Comment: 16 pages, 17 figure
Protecting the Primordial Baryon Asymmetry From Erasure by Sphalerons
If the baryon asymmetry of the universe was created at the GUT scale,
sphalerons together with exotic sources of -violation could have erased
it, unless the latter satisfy stringent bounds. We elaborate on how the small
Yukawa coupling of the electron drastically weakens previous estimates of these
bounds.Comment: 41 pp., 4 latex figures included and 3 uuencoded or postscript
figures available by request, UMN-TH-1213-9
An efficient algorithm for computing the Baker-Campbell-Hausdorff series and some of its applications
We provide a new algorithm for generating the Baker--Campbell--Hausdorff
(BCH) series Z = \log(\e^X \e^Y) in an arbitrary generalized Hall basis of
the free Lie algebra generated by and . It is based
on the close relationship of with a Lie algebraic structure
of labeled rooted trees. With this algorithm, the computation of the BCH series
up to degree 20 (111013 independent elements in ) takes less
than 15 minutes on a personal computer and requires 1.5 GBytes of memory. We
also address the issue of the convergence of the series, providing an optimal
convergence domain when and are real or complex matrices.Comment: 30 page
On Properties of Boundaries and Electron Conductivity in Mesoscopic Polycrystalline Silicon Films for Memory Devices
We present the results of molecular dynamics modeling on the structural
properties of grain boundaries (GB) in thin polycrystalline films. The
transition from crystalline boundaries with low mismatch angle to amorphous
boundaries is investigated. It is shown that the structures of the GBs satisfy
a thermodynamical criterion. The potential energy of silicon atoms is closely
related with a geometrical quantity -- tetragonality of their coordination with
their nearest neighbors. A crossover of the length of localization is observed.
To analyze the crossover of the length of localization of the single-electron
states and properties of conductance of the thin polycrystalline film at low
temperature, we use a two-dimensional Anderson localization model, with the
random one-site electron charging energy for a single grain (dot), random
non-diagonal matrix elements, and random number of connections between the
neighboring grains. The results on the crossover behavior of localization
length of the single-electron states and characteristic properties of
conductance are presented in the region of parameters where the transition from
an insulator to a conductor regimes takes place.Comment: 8 pages, 3 figure
Primordial Magnetic Fields, Right Electrons, and the Abelian Anomaly
In the standard model there are charges with abelian anomaly only (e.g.
right-handed electron number) which are effectively conserved in the early
universe until some time shortly before the electroweak scale. A state at
finite chemical potential of such a charge, possibly arising due to asymmetries
produced at the GUT scale, is unstable to the generation of hypercharge
magnetic field. Quite large magnetic fields ( gauss at GeV with typical inhomogeneity scale ) can be
generated. These fields may be of cosmological interest, potentially acting as
seeds for amplification to larger scale magnetic fields through non-linear
mechanisms. Previously derived bounds on exotic violating operators may
also be evaded.Comment: Revised version, to appear in Phys. Rev. Lett.. Analysis has been
extended to larger chemical potentials, for which large magnetic fields
survive at the electroweak scale. Previous bounds on violating
operators are also evaded in this cas
- …