10,082 research outputs found
Symmetry and Z_2-Orbifolding Approach in Five-dimensional Lattice Gauge Theory
In a lattice gauge-Higgs unification scenario using a Z_2-orbifolded
extra-dimension, we find a new global symmetry in a case of SU(2) bulk gauge
symmetry. It is a global symmetry on sites in a fixed point with respect to
Z_2-orbifolding, independent of the bulk gauge symmetry. It is shown that the
vacuum expectation value of a Z_2-projected Polyakov loop is a good order
parameter of the new symmetry. The effective theory on lattice is also
discussed.Comment: 13 pages, 3 figures; refined the explanation
Investigation of Visual Management Cases in Construction by an Analytical Framework from Manufacturing
Along with the progress of globalization, speed and efficiency have become more critical for any industry than ever before. In this sense, the concept and methods of lean management, promoting these performances, have been deployed from manufacturing, its origin industry, to other industries. This paper deals with this management style in the construction industry, called lean construction. In particular, visual management (VM) as one effective tool in this scheme is focused on. A number of VM cases, 306 in total, was collected from both construction and manufacturing sites and investigated by the so-called 5W1H analytical framework developed in the manufacturing industry. Obtained results suggest that the VM cases in construction have common attributes such as purpose and location, target to attain, users’ attributes, timing to use and elemental technologies for case development. A comparison analysis of the VM cases from construction and those from manufacturing was also carried out, for a mutual transfer of this technology between these industries
Induced Magnetic Ordering by Proton Irradiation in Graphite
We provide evidence that proton irradiation of energy 2.25 MeV on
highly-oriented pyrolytic graphite samples triggers ferro- or ferrimagnetism.
Measurements performed with a superconducting quantum interferometer device
(SQUID) and magnetic force microscopy (MFM) reveal that the magnetic ordering
is stable at room temperature.Comment: 3 Figure
Scattering and Pairing in Cuprate Superconductors
The origin of the exceptionally strong superconductivity of cuprates remains
a subject of debate after more than two decades of investigation. Here we
follow a new lead: The onset temperature for superconductivity scales with the
strength of the anomalous normal-state scattering that makes the resistivity
linear in temperature. The same correlation between linear resistivity and Tc
is found in organic superconductors, for which pairing is known to come from
fluctuations of a nearby antiferromagnetic phase, and in pnictide
superconductors, for which an antiferromagnetic scenario is also likely. In the
cuprates, the question is whether the pseudogap phase plays the corresponding
role, with its fluctuations responsible for pairing and scattering. We review
recent studies that shed light on this phase - its boundary, its quantum
critical point, and its broken symmetries. The emerging picture is that of a
phase with spin-density-wave order and fluctuations, in broad analogy with
organic, pnictide, and heavy-fermion superconductors.Comment: To appear in Volume 1 of the Annual Review of Condensed Matter
Physic
Long-Range Excitons in Optical Absorption Spectra of Electroluminescent Polymer Poly(para-phenylenevinylene)
The component of photoexcited states with large spatial extent is
investigated for poly(para-phenylenevinylene) using the intermediate exciton
theory. We find a peak due to long-range excitons at the higher-energy side of
the lowest main feature of optical spectra. The fact that the onset of
long-range excitons is located near the energy gap is related to the mechanisms
of large photocurrents measured in such energy regions. We show that a large
value of the hopping integral is realistic for characterizing optical
excitations.Comment: To be published in J. Phys. Soc. Jpn. (Letters
Rotating and infalling motion around the high-mass young stellar object Cepheus A-HW2 observed with the methanol maser at 6.7 GHz
We have measured the internal proper motions of the 6.7 GHz methanol masers
associated with Cepheus A (Cep A) HW2 using Very Long Baseline Interferometery
(VLBI) observations. We conducted three epochs of VLBI monitoring observations
of the 6.7 GHz methanol masers in Cep A-HW2 with the Japanese VLBI Network
(JVN) over the period between 2006-2008. In 2006, we were able to use
phase-referencing to measure the absolute coordinates of the maser emission
with an accuracy of a few milliarcseconds. We compared the maser distribution
with other molecular line observations that trace the rotating disk. We
measured the internal proper motions for 29 methanol maser spots, of which 19
were identified at all three epochs and the remaining ten at only two epochs.
The magnitude of proper motions ranged from 0.2 to 7.4 km/s, with an average of
3.1 km/s. Although there are large uncertainties in the observed internal
proper motions of the methanol maser spots in Cep A, they are well fitted by a
disk that includes both rotation and infall velocity components. The derived
rotation and infall velocities at the disk radius of 680 au are 0.5 +- 0.7 and
1.8 +- 0.7 km/s, respectively. Assuming that the modeled disk motion accurately
represents the accretion disk around the Cep A-HW2 high-mass YSO, we estimated
the mass infall rate to be 3 x 10^{-4} n_8 Msun/yr (n_8 is the gas volume
density in units of 10^{8} cm^{-3}). The combination of the estimated mass
infall rate and the magnitude of the fitted infall velocity suggests that Cep
A-HW2 is at an evolutionary phase of active gas accretion from the disk onto
the central high-mass YSO. The infall momentum rate is estimated to be 5 x
10^{-4} n_8 Msun/yr km/s, which is larger than the estimated stellar radiation
pressure of the HW2 object, supporting the hypothesis that this object is in an
active gas accretion phase.Comment: 16 pages, 6 figures, 5 tables, accepted for publication in Astronomy
& Astrophysic
1 um Excess Sources in the UKIDSS - I. Three T Dwarfs in the SDSS Southern Equatorial Stripe
We report the discovery of two field brown dwarfs, ULAS J0128-0041 and ULAS
J0321+0051, and the rediscovery of ULAS J0226+0051 (IfA 0230-Z1), in the Sloan
Digital Sky Survey (SDSS) southern equatorial stripe. They are found in the
course of our follow-up observation program of 1 um excess sources in the
United Kingdom Infrared Telescope Infrared Deep Sky Survey. The Gemini
Multi-Object Spectrographs spectra at red optical wavelengths (6500-10500 A)
are presented, which reveal that they are early-T dwarfs. The classification is
also supported by their optical to near-infrared colors. It is noted that ULAS
J0321+0051 is one of the faintest currently known T dwarfs. The estimated
distances to the three objects are 50-110 pc, thus they are among the most
distant field T dwarfs known. Dense temporal coverage of the target fields
achieved by the SDSS-II Supernova Survey allows us to perform a simple
time-series analysis, which leads to the finding of significant proper motions
of 150-290 mas/yr or the transverse velocities of 40-100 km/s for ULAS
J0128-0041 and ULAS J0226+0051. We also find that there are no detectable,
long-term (a-few-year) brightness variations above a few times 0.1 mag for the
two brown dwarfs.Comment: Accepted for publication in the Astronomical Journal; Typos correcte
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