131,004 research outputs found
Does the WTO Matter? A Non-parametric view
WTO, Trade, Foreign Direct Investment, and Patenting
Wind and turbine characteristics needed for integration of wind turbine arrays into a utility system
Wind data and wind turbine generator (WTG) performance characteristics are often available in a form inconvenient for use by utility planners and engineers. The steps used by utility planners are summarized and the type of wind and WTG data needed for integration of WTG arrays suggested. These included long term yearly velocity averages for preliminary site feasibility, hourly velocities on a 'wind season' basis for more detailed economic analysis and for reliability studies, worst-case velocity profiles for gusts, and various minute-to-hourly velocity profiles for estimating the effect of longer-term wind fluctuations on utility operations. wind turbine data needed includes electrical properties of the generator, startup and shutdown characteristics, protection characteristics, pitch control response and control strategy, and electro-mechanical model for stability analysis
Rigorous Approach to the Gravitational Lensing
We revisit a weak gravitational lensing problem by constructing a setup which
describes the actual system as accurately as possible and solving the null
geodesic equations. Details are given for the case of a Universe driven only by
a cosmological constant, \Lambda, which confirm the conventional results: The
conventional lensing analysis is correct as it is, without any need for
correction of O(\Lambda). We also treat the cases of the lensing in generic FRW
backgrounds.Comment: 6 pages, the discussion is revise
Spin Polarization of Photoelectrons from Topological Insulators
We show that the degree of spin polarization of photoelectrons from the
surface states of topological insulators is 100% if fully-polarized light is
used as in typical photoemission measurements, and hence can be significantly
"higher" than that of the initial state. Further, the spin orientation of these
photoelectrons in general can also be very different from that of the initial
surface state and is controlled by the photon polarization; a rich set of
predicted phenomena have recently been confirmed by spin- and angle-resolved
photoemission experiments.Comment: A sentence on the effect of the imaginary part of the initial-state
electron self energy is added to the published versio
Making Massless Dirac Fermions from Patterned Two-Dimensional Electron Gases
Analysis of the electronic structure of an ordinary two-dimensional electron
gas (2DEG) under an appropriate external periodic potential of hexagonal
symmetry reveals that massless Dirac fermions are generated near the corners of
the supercell Brillouin zone. The required potential parameters are found to be
achievable under or close to laboratory conditions. Moreover, the group
velocity is tunable by changing either the effective mass of the 2DEG or the
lattice parameter of the external potential, and it is insensitive to the
potential amplitude. The finding should provide a new class of systems other
than graphene for investigating and exploiting massless Dirac fermions using
2DEGs in semiconductors.Comment: 5 pages, 4 figures, significant revision of abstract, text, and
figure
The British American Rules: An experimental examination of pre-trial bargaining within the shadow of the law
A commonly held view is that the frequency and value of pre-trial settlements in civil disputes are greatly influenced by the cost allocation regime that is in place if the case goes to trial. There is a large and growing theoretical literature on this subject but almost no empirical evidence. This is due simply to the scarcity of relevant data owing to the confidentiality generally associated with such matters. However, the area is an ideal one to analyse experimentally. In this paper we consider the effect of the British and American rules for cost allocation using such an experimental methodology. We find that the two rules produce no difference in the frequency of pre-trial settlements but that the British rule produces higher settlements (pro-pursuer) if the probability of the pursuer winning is large.
First principles investigation of transition-metal doped group-IV semiconductors: RY (R=Cr, Mn, Fe; Y=Si, Ge)
A number of transition-metal (TM) doped group-IV semiconductors,
RY (R=Cr, Mn and Fe; Y=Si, Ge), have been studied by the first
principles calculations. The obtained results show that antiferromagnetic (AFM)
order is energetically more favored than ferromagnetic (FM) order in Cr-doped
Ge and Si with =0.03125 and 0.0625. In 6.25% Fe-doped Ge, FM interaction
dominates in all range of the R-R distances while for Fe-doped Ge at 3.125% and
Fe-doped Si at both concentrations of 3.125% and 6.25%, only in a short R-R
range can the FM states exist. In the Mn-doped case, the RKKY-like mechanism
seems to be suitable for the Ge host matrix, while for the Mn-doped Si, the
short-range AFM interaction competes with the long-range FM interaction. The
different origin of the magnetic orders in these diluted magnetic
semiconductors (DMSs) makes the microscopic mechanism of the ferromagnetism in
the DMSs more complex and attractive.Comment: 14 pages, 2 figures, 6 table
- …