10,653 research outputs found
Consistency Conditions of the Faddeev-Niemi-Periwal Ansatz for the SU(N) Gauge Field
The consistency condition of the Faddeev-Niemi ansatz for the gauge-fixed
massless SU(2) gauge field is discussed. The generality of the ansatz is
demonstrated by obtaining a sufficient condition for the existence of the
three-component field introduced by Faddeev and Niemi. It is also shown that
the consistency conditions determine this three-component field as a functional
of two arbitrary functions. The consistency conditions corresponding to the
Periwal ansatz for the SU(N) gauge field with N larger than 2 are also
obtained. It is shown that the gauge field obeying the Periwal ansatz must
satisfy extra (N-1)(N-2)/2 conditions.Comment: PTP Tex, 15 pages, Eq.(3.18) inserte
Non-Abelian Stokes Theorem for Loop Variables Associated with Nontrivial Loops
The non-Abelian Stokes theorem for loop variables associated with nontrivial
loops (knots and links) is derived. It is shown that a loop variable is in
general different from unity even if the field strength vanishes everywhere on
the surface surrounded by the loop.Comment: 18 pages,10 Postscript figures, PTP Tex, Journal-ref adde
Field Effect Transistor Based on KTaO3 Perovskite
An n-channel accumulation-type field effect transistor (FET) has been
fabricated utilizing a KTaO3 single crystal as an active element and a
sputtered amorphous Al2O3 film as a gate insulator. The device demonstrated an
ON/OFF ratio of 10^4 and a field effect mobility of 0.4cm^2/Vs at room
temperature, both of which are much better than those of the SrTiO3 FETs
reported previously. The field effect mobility was almost temperature
independent down to 200K. Our results indicate that the Al2O3 / KTaO3 interface
is worthy of further investigations as an alternative system of future oxide
electronics.Comment: 3 pages, 3 Postscript figures, submitted to Appl.Phys.Let
Renormalization-group and numerical analysis of a noisy Kuramoto-Sivashinsky equation in 1+1 dimensions
The long-wavelength properties of a noisy Kuramoto-Sivashinsky (KS) equation
in 1+1 dimensions are investigated by use of the dynamic renormalization group
(RG) and direct numerical simulations. It is shown that the noisy KS equation
is in the same universality class as the Kardar-Parisi-Zhang (KPZ) equation in
the sense that they have scale invariant solutions with the same scaling
exponents in the long-wavelength limit. The RG analysis reveals that the RG
flow for the parameters of the noisy KS equation rapidly approach the KPZ fixed
point with increasing the strength of the noise. This is supplemented by the
numerical simulations of the KS equation with a stochastic noise, in which the
scaling behavior of the KPZ equation can be easily observed even in the
moderate system size and time.Comment: 12pages, 7figure
Hybrid ECAL: Optimization and Related Developments
Hybrid ECAL is a cost-conscious option of electromagnetic calorimeter (ECAL)
for particle flow calorimetry to be used in a detector of International Linear
Collider (ILC). It is a combination of silicon-tungsten ECAL, which realizes
high granularity and robust measurement of electromagnetic shower, and
scintillator-tungsten ECAL, which gives affordable cost with similar
performance to silicon. Optimization and a data acquisition trial in a test
bench for the hybrid ECAL are described in this article.Comment: 7 pages, 4 figures, Talk presented at the International Workshop on
Future Linear Colliders (LCWS14), Belgrade, Serbia, 6-10 October 201
Characteristics of the wavelength of ripples on icicles
It is known that the wavelength of the ripples on icicles in nature is of
centimeter-scale. Such study on morphological instability of ice-water
interface during ice growth from flowing supercooled water film with one side
being a free surface has recently been made [K. Ueno, Phys. Rev. E 68, 021603
(2003)]. This is a first theoretical study taking into account the influence of
the shape of the water-air surface on the growth condition of infinitesimal
disturbances of the ice-water interface. A simpler formula to determine the
wavelength of the ripples than that in the previous paper is derived. It seems
that the wavelength of ripples is insensitive to the water supply rates,
diameters of the icicles and surrounding air temperatures. The details of
dependence of the wavelengh of ripples on these parameters are investigated.Comment: 15 pages, 6 figure
Visibility and aerosol measurement by diode-laser random-modulation CW lidar
Examples of diode laser (DL) random-modulation continuous wave (RM-CW) lidar measurements are reported. The ability of the measurement of the visibility, vertical aerosol profile, and the cloud ceiling height is demonstrated. Although the data shown here were all measured at night time, the daytime measurement is, of course, possible. For that purpose, accurate control of the laser frequency to the center frequency of a narrow band filter is required. Now a new system with a frequency control is under construction
Field-Effect Transistor on SrTiO3 with sputtered Al2O3 Gate Insulator
A field-effect transistor that employs a perovskite-type SrTiO3 single
crystal as the semiconducting channel is revealed to function as n-type
accumulation-mode device with characteristics similar to that of organic FET's.
The device was fabricated at room temperature by sputter-deposition of
amorphous Al2O3 films as a gate insulator on the SrTiO3 substrate. The
field-effect(FE) mobility is 0.1cm2/Vs and on-off ratio exceeds 100 at room
temperature. The temperature dependence of the FE mobility down to 2K shows a
thermal-activation-type behavior with an activation energy of 0.6eV
The invariant imbedding equation for the dissipation function of a homogeneous finite slab
Differential-integral equation for dissipation function and derivation of conservation relationship connecting reflection, transmission and dissipation functions of finite sla
Morphological instability of the solid-liquid interface in crystal growth under supercooled liquid film flow and natural convection airflow
Ring-like ripples on the surface of icicles are an example of morphological
instability of the ice-water interface during ice growth under supercooled
water film flow. The surface of icicles is typically covered with ripples of
about 1 cm in wavelength, and the wavelength appears to be almost independent
of external temperature, icicle radius, and volumetric water flow rate. One
side of the water layer consists of the water-air surface and growing ice is
the other. This is one of the more complicated moving phase boundary problems
with two interfaces. A recent theoretical work [K. Ueno, Phys. Rev. E 68,
(2003) 021603] to address the underlying instability that produces ripples is
based on the assumption of the absence of airflow around icicles. In this
paper, we extend the previous theoretical framework to include a natural
convection airflow ahead of the water-air surface and consider whether the
effect of natural convection airflow on the wavelength of ripples produced on
an ice surface is essential or not.Comment: 19 pages, 5 figure
- …