22,851 research outputs found
Economics of polysilicon process: A view from Japan
The production process of solar grade silicon (SOG-Si) through trichlorosilane (TCS) was researched in a program sponsored by New Energy Development Organization (NEDO). The NEDO process consists of the following two steps: TCS production from by-product silicon tetrachloride (STC) and SOG-Si formation from TCS using a fluidized bed reactor. Based on the data obtained during the research program, the manufacturing cost of the NEDO process and other polysilicon manufacturing processes were compared. The manufacturing cost was calculated on the basis of 1000 tons/year production. The cost estimate showed that the cost of producing silicon by all of the new processes is less than the cost by the conventional Siemens process. Using a new process, the cost of producing semiconductor grade silicon was found to be virtually the same with any to the TCS, diclorosilane, and monosilane processes when by-products were recycled. The SOG-Si manufacturing processes using the fluidized bed reactor, which needs further development, shows a greater probablility of cost reduction than the filament processes
Test of QEDPS: A Monte Carlo for the hard photon distributions in e+ e- annihilation proecss
The validity of a photon shower generator QEDPS has been examined in detail.
This is formulated based on the leading-logarithmic renormalization equation
for the electron structure function and it provides a photon shower along the
initial e+-. The main interest in the present work is to test the reliability
of the generator to describe a process accompanying hard photons which are
detected. For this purpose, by taking the HZ production as the basic reaction,
the total cross section and some distributions of the hard photons are compared
between two cases that these photons come from either those generated by QEDPS
or the hard process e+e- -> H Z gamma gamma. The comparison performed for the
single and the double hard photon has shown a satisfactory agreement which
demonstrated that the model is self-consistent.Comment: 22 pages, 4 Postscript figures, LaTeX, uses epsf.te
A QED Shower Including the Next-to-leading Logarithm Correction in e+e- Annihilation
We develop an event generator, NLL-QEDPS, based on the QED shower including
the next-to-leading logarithm correction in the e^+e^- annihilation. The shower
model is the Monte Carlo technique to solve the renormalization group equation
so that they can calculate contributions of alpha^m log^n(S/m_e^2) for any m
and n systematically. Here alpha is the QED coupling, m_e is the mass of
electron and S is the square of the total energy in the e^+e^- system. While
the previous QEDPS is limited to the leading logarithm approximation which
includes only contributions of (alpha log(S/m_e^2))^n, the model developed here
contains terms of alpha(alpha log(S/m_e^2))^n, the the next-to-leading
logarithm correction.
The shower model is formulated for the initial radiation in the e^+e^-
annihilation. The generator based on it gives us events with q^2, which is a
virtual mass squared of the virtual photon and/or Z-boson, in accuracy of
0.04%, except for small q^2/S.Comment: 35 pages, 1 figure(eps-file
Efficient Method for Quantum Number Projection and Its Application to Tetrahedral Nuclear States
We have developed an efficient method for quantum number projection from most
general HFB type mean-field states, where all the symmetries like axial
symmetry, number conservation, parity and time-reversal invariance are broken.
Applying the method, we have microscopically calculated, for the first time,
the energy spectra based on the exotic tetrahedral deformation in
Zr. The nice low-lying rotational spectra, which have all
characteristic features of the molecular tetrahedral rotor, are obtained for
large tetrahedral deformation, \alpha_{32} \gtsim 0.25, while the spectra are
of transitional nature between vibrational and rotational with rather high
excitation energies for Comment: Trivial mistakes are correcte
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