631 research outputs found
How present am I: three virtual reality facilities testing the fear of falling
Virtual reality environments have long been used in studies related to architecture simulation. The main objective of this paper is to measure the sense of presence that different virtual reality devices provide to users so as to evaluate their effectiveness when used to simulate real environments and draw conclusions of people’s behaviours when using them. The study also aims at investigating, in a quantitative way, the influence of architectural elements on the comfort of use of a built environment, namely considering the fear of falling reported by adults while using these architectural elements. Using a between-subjects design randomly distributed between two experimental conditions (safe and unsafe), a set of three studies were conducted in three different virtual reality environments using a 5-sided-CAVE, a Powerwall or a Head Mounted Display. The study shows that immersive virtual reality devices give users a higher sense of presence than semi-immersive ones. One of the conclusions of the study is that a higher sense of presence helps to enhance the building spaces perceived impacts on users (in this case the fear of falling).info:eu-repo/semantics/publishedVersio
Fluctuation-induced phase in CsCuCl3 in transverse magnetic field: Theory
CsCuCl3 is a quantum triangular antiferromagnet, ferromagnetically stacked,
with an incommensurate (IC) structure due to a Dzyaloshinskii-Moriya
interaction. Because of the classical degeneracy caused by the frustration,
fluctuations in CsCuCl3 have extraordinarily large effects, such as the phase
transition in longitudinal magnetic field (normal to the planes, parallel to
the IC wavenumber q) and the plateau in q in transverse field (perpendicular to
q). We argue that fluctuations are responsible also for the new IC phase
discovered in transverse field near the Neel temperature T_N, by T. Werner et
al. [Solid State Commun. 102, p.609 (1997)]. We develop and analyse the
corresponding minimal Landau theory; the effects of fluctuations on the
frustration are included phenomenologically, by means of a biquadratic term.
The Landau theory gives two IC phases, one familiar from previous studies;
properties of the new IC phase, which occupies a pocket of the
temperature-field phase diagram near T_N, agree qualitatively with those of the
new phase found experimentally.Comment: 12 pages, revtex, 4 postscript figures, submitted to J. Phys:
Condens. Matte
Flow equation analysis of the anisotropic Kondo model
We use the new method of infinitesimal unitary transformations to calculate
zero temperature correlation functions in the strong-coupling phase of the
anisotropic Kondo model. We find the dynamics on all energy scales including
the crossover behaviour from weak to strong coupling. The integrable structure
of the Hamiltonian is not used in our approach. Our method should also be
useful in other strong-coupling models since few other analytical methods allow
the evaluation of their correlation functions on all energy scales.Comment: 4 pages RevTeX, 2 eps figures include
Oblique triangular antiferromagnetic phase in CsCuCoCl
The spin-1/2 stacked triangular antiferromagnet CsCuCoCl with
undergoes two phase transitions at zero field. The
low-temperature phase is produced by the small amount of Co doping. In
order to investigate the magnetic structures of the two ordered phases, the
neutron elastic scattering experiments have been carried out for the sample
with . It is found that the intermediate phase is identical to
the ordered phase of CsCuCl, and that the low-temperature phase is an
oblique triangular antiferromagnetic phase in which the spins form a triangular
structure in a plane tilted from the basal plane. The tilting angle which is
42 at K decreases with increasing temperature, and becomes
zero at K. An off-diagonal exchange term is proposed as the
origin of the oblique phase.Comment: 6 pages, 7 figure
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