13,689 research outputs found
Horizontal divergence of typhoon-generated gravity waves in the upper troposphere and lower stratosphere (UTLS) and its influence on typhoon evolution
The characteristics of horizontal divergence induced by typhoon-generated
gravity waves (HDTGWs) and the influence of HDTGW on typhoon evolution are
investigated based on the simulation results of Typhoon Saomai (2006) using
the Weather Research and Forecasting (WRF) model. The power spectral density
of HDTGW shows dominant powers at horizontal wavelengths of 20–30 km and at
periods of less than 1 h. This is associated with gravity waves
generated by vigorous convective clouds in an inner core region of the
typhoon. However, the domain-averaged HDTGW in the upper troposphere and
lower stratosphere had a spectral peak at 24 h, which is well correlated
with the minimum sea-level pressure of the typhoon, especially during a
rapidly developing period. The 24 h period of the averaged HDTGW stems
from the inertia–gravity waves generated by the convective clouds in the
spiral rainbands, and showed no clear association with the thermal tides or
the diurnal variation of precipitation
Putative spin liquid in the triangle-based iridate BaIrTiO
We report on thermodynamic, magnetization, and muon spin relaxation
measurements of the strong spin-orbit coupled iridate BaIrTiO,
which constitutes a new frustration motif made up a mixture of edge- and
corner-sharing triangles. In spite of strong antiferromagnetic exchange
interaction of the order of 100~K, we find no hint for long-range magnetic
order down to 23 mK. The magnetic specific heat data unveil the -linear and
-squared dependences at low temperatures below 1~K. At the respective
temperatures, the zero-field muon spin relaxation features a persistent spin
dynamics, indicative of unconventional low-energy excitations. A comparison to
the isostructural compound BaRuTiO suggests that a concerted
interplay of compass-like magnetic interactions and frustrated geometry
promotes a dynamically fluctuating state in a triangle-based iridate.Comment: Physical Review B accepte
A micro optical probe for edge contour evaluation of diamond cutting tools
This paper presents a micro optical probe, which is employed to evaluate
edge contours of single point diamond tools with a size in a range of
several millimetres. The micro optical probe consists of a laser source with
a wavelength of 405 nm, an objective lens with a numerical aperture of 0.25,
a photodiode for measurement, and a compensating optical system including
another photodiode for compensation of laser intensity. A collimated laser
beam, which is divided by a beam splitter in the compensating optical
system, is focused by the objective lens so that the focused spot can be
used as the micro optical probe. The micro optical probe traces over an edge
contour of an objective tool while the signals of both the two photodiodes
are monitored. The output of the photodiode for measurement is compensated
by using that of the photodiode for laser intensity compensation to
eliminate the influence of the laser instability. The signal of the
photodiode for measurement is used to define the deviation of edge contour
within the diameter of the micro optical probe. To verify the feasibility of
the developed optical probe, the optical system was mounted on a diamond
turning machine, and some experiments were carried out. Two types of edge
contours of the diamond tools having a straight cutting edge and a round
cutting edge were measured on the machine
Design and construction of a remote monitoring and control system for a dehumidifier combined with a heating module
Background: Protected cultivation (e.g., greenhouse) is spreading mainly for high-income crops such as paprika, strawberry, and tomato. The temperature and the humidity are especially important during cultivation. A dehumidifier combined with a heating module is under development. In the study, a remote monitoring and control system for the prototype was designed and constructed.
Methods: The dehumidifier prototype was composed of a dehumidifier, a fan blower, and heating modules. The remote monitoring and control system was composed of temperature-humidity measuring sensor network, a central processing module, a dehumidifier network, and smartphone application. First, the sensing network was tested for different communication distances and number of data variables. Second, remote monitoring and control performance was tested using the smartphone application by signal intensity and time of the day.
Results and discussion: Monitoring performance was favourable within 15 m distance with the tested ZigBee module, and a wireless communication network was established considering the communication distance and greenhouse length (i.e., 100 m). Remote monitoring and control was successful for all of the tested signal intensity and time of the day, although the data transmission speed was affected significantly. Components of the dehumidifier were successfully controlled within 30 s.
Conclusion: The remote monitoring and control system was tested only under experimental conditions. For improved performance and practical application, the prototype needs to be further tested under crop growing conditions, and the control algorithm needs to be also improved
Influence of oxygen vacancy on the electronic structure of HfO film
We investigated the unoccupied part of the electronic structure of the
oxygen-deficient hafnium oxide (HfO) using soft x-ray absorption
spectroscopy at O and Hf edges. Band-tail states beneath the
unoccupied Hf 5 band are observed in the O -edge spectra; combined with
ultraviolet photoemission spectrum, this indicates the non-negligible
occupation of Hf 5 state. However, Hf -edge magnetic circular dichroism
spectrum reveals the absence of a long-range ferromagnetic spin order in the
oxide. Thus the small amount of electron gained by the vacancy formation
does not show inter-site correlation, contrary to a recent report [M.
Venkatesan {\it et al.}, Nature {\bf 430}, 630 (2004)].Comment: 5 pages, 4 figures, submitted to Phys. Rev.
Charge states and magnetic ordering in LaMnO3/SrTiO3 superlattices
We investigated the magnetic and optical properties of
[(LaMnO3)n/(SrTiO3)8]20 (n = 1, 2, and 8) superlattices grown by pulsed laser
deposition. We found a weak ferromagnetic and semiconducting state developed in
all superlattices. An analysis of the optical conductivity showed that the
LaMnO3 layers in the superlattices were slightly doped. The amount of doping
was almost identical regardless of the LaMnO3 layer thickness up to eight unit
cells, suggesting that the effect is not limited to the interface. On the other
hand, the magnetic ordering became less stable as the LaMnO3 layer thickness
decreased, probably due to a dimensional effect.Comment: 17 pages including 4 figures, accepted for publication in Phys. Rev.
Tailoring a two-dimensional electron gas at the LaAlO3/SrTiO3 (001) interface by epitaxial strain
Recently a metallic state was discovered at the interface between insulating
oxides, most notably LaAlO3 and SrTiO3. Properties of this two-dimensional
electron gas (2DEG) have attracted significant interest due to its potential
applications in nanoelectronics. Control over this carrier density and mobility
of the 2DEG is essential for applications of these novel systems, and may be
achieved by epitaxial strain. However, despite the rich nature of strain
effects on oxide materials properties, such as ferroelectricity, magnetism, and
superconductivity, the relationship between the strain and electrical
properties of the 2DEG at the LaAlO3/SrTiO3 heterointerface remains largely
unexplored. Here, we use different lattice constant single crystal substrates
to produce LaAlO3/SrTiO3 interfaces with controlled levels of biaxial epitaxial
strain. We have found that tensile strained SrTiO3 destroys the conducting
2DEG, while compressively strained SrTiO3 retains the 2DEG, but with a carrier
concentration reduced in comparison to the unstrained LaAlO3/SrTiO3 interface.
We have also found that the critical LaAlO3 overlayer thickness for 2DEG
formation increases with SrTiO3 compressive strain. Our first-principles
calculations suggest that a strain-induced electric polarization in the SrTiO3
layer is responsible for this behavior. It is directed away from the interface
and hence creates a negative polarization charge opposing that of the polar
LaAlO3 layer. This both increases the critical thickness of the LaAlO3 layer,
and reduces carrier concentration above the critical thickness, in agreement
with our experimental results. Our findings suggest that epitaxial strain can
be used to tailor 2DEGs properties of the LaAlO3/SrTiO3 heterointerface
Discovery From Non-Parties (Third-Party Discovery) in International Arbitration
International arbitration rules and many arbitration laws usually provide procedures that permit tribunals to order parties to disclose documents and other materials to the other parties.1 More complex are the rules that determine opportunities to obtain discovery from persons that are not party to the arbitration (third-party discovery). This article will review third-party discovery under the Federal Arbitration Act (FAA) and the provisions of the US Code s.1782 that authorise US courts to act in aid of actions before foreign tribunals. Section 1782 has unique interest at this time because it figured prominently in the EU antitrust investigation of Intel that was initiated on request from Advanced Micro Devices (AMD). Early in that investigation, AMD filed a s.1782 request in the US District Court to obtain evidence from US sources for submission to the DG-Competition of the European Commission (EC). This request ultimately led to the Supreme Court’s decision in Intel Corp v Advanced Micro Devices Inc2 which appeared to significantly expand the scope of s.1782. Ironically, after AMD won on key legal issues in the Supreme Court, the District Court on remand exercised its discretion and denied the request for judicial assistance. This paper first describes the FAA non-party discovery rules and the split among the federal appellate courts concerning the authority of arbitrators to order prehearing discovery from non-parties. Next, it provides an analysis of the meaning of the terms “interested party” and “tribunal”—terms that were controversially interpreted by the Supreme Court in Intel and are essential to the application of s.1782. Finally, it discusses the “discretionary” factors used by the federal courts in deciding whether to grant a s.1782 request even when the statutory criteria are met. The opportunity to exercise this discretion seems to rebut the argument that the Supreme Court’s interpretation of s.1782 gives participants before foreign tribunals more discovery rights in the United States than are available to the parties in arbitrations covered by the FAA
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