23,144 research outputs found
Economics of polysilicon processes
Techniques are being developed to provide lower cost polysilicon material for solar cells. Existing technology which normally provides semiconductor industry polysilicon material is undergoing changes and also being used to provide polysilicon material for solar cells. Economics of new and existing technologies are presented for producing polysilicon. The economics are primarily based on the preliminary process design of a plant producing 1,000 metric tons/year of silicon. The polysilicon processes include: Siemen's process (hydrogen reduction of trichlorosilane); Union Carbide process (silane decomposition); and Hemlock Semiconductor process (hydrogen reduction of dichlorosilane). The economics include cost estimates of capital investment and product cost to produce polysilicon via the technology. Sensitivity analysis results are also presented to disclose the effect of major paramentes such as utilities, labor, raw materials and capital investment
Doping evolution of the electronic structure in the single-layer cuprates BiSrLaCuO: Comparison with other single-layer cuprates
We have performed angle-resolved photoemission and core-level x-ray
photoemission studies of the single-layer cuprate
BiSrLaCuO (Bi2201) and revealed the doping
evolution of the electronic structure from the lightly-doped to optimally-doped
regions. We have observed the formation of the dispersive quasi-particle band,
evolution of the Fermi ``arc'' into the Fermi surface and the shift of the
chemical potential with hole doping as in other cuprates. The doping evolution
in Bi2201 is similar to that in CaNaCuOCl (Na-CCOC),
where a rapid chemical potential shift toward the lower Hubbard band of the
parent insulator has been observed, but is quite different from that in
LaSrCuO (LSCO), where the chemical potential does not
shift, yet the dispersive band and the Fermi arc/surface are formed around the
Fermi level already in the lightly-doped region. The (underlying) Fermi surface
shape and band dispersions are quantitatively analyzed using tight-binding fit,
and the deduced next-nearest-neighbor hopping integral also confirm the
similarity to Na-CCOC and the difference from LSCO
An Upsilon Point in a Spin Model
We present analytic evidence for the occurrence of an upsilon point, an
infinite checkerboard structure of modulated phases, in the ground state of a
spin model. The structure of the upsilon point is studied by calculating
interface--interface interactions using an expansion in inverse spin
anisotropy.Comment: 18 pages ReVTeX file, including 6 figures encoded with uufile
Prediction of protein submitochondria locations by hybridizing pseudo-amino acid composition with various physicochemical features of segmented sequence
BACKGROUND: Knowing the submitochondria localization of a mitochondria protein is an important step to understand its function. We develop a method which is based on an extended version of pseudo-amino acid composition to predict the protein localization within mitochondria. This work goes one step further than predicting protein subcellular location. We also try to predict the membrane protein type for mitochondrial inner membrane proteins. RESULTS: By using leave-one-out cross validation, the prediction accuracy is 85.5% for inner membrane, 94.5% for matrix and 51.2% for outer membrane. The overall prediction accuracy for submitochondria location prediction is 85.2%. For proteins predicted to localize at inner membrane, the accuracy is 94.6% for membrane protein type prediction. CONCLUSION: Our method is an effective method for predicting protein submitochondria location. But even with our method or the methods at subcellular level, the prediction of protein submitochondria location is still a challenging problem. The online service SubMito is now available at
Maximally Symmetric Minimal Unification Model SO(32) with Three Families in Ten Dimensional Space-time
Based on a maximally symmetric minimal unification hypothesis and a quantum
charge-dimension correspondence principle, it is demonstrated that each family
of quarks and leptons belongs to the Majorana-Weyl spinor representation of
14-dimensions that relate to quantum spin-isospin-color charges. Families of
quarks and leptons attribute to a spinor structure of extra 6-dimensions that
relate to quantum family charges. Of particular, it is shown that 10-dimensions
relating to quantum spin-family charges form a motional 10-dimensional quantum
space-time with a generalized Lorentz symmetry SO(1,9), and 10-dimensions
relating to quantum isospin-color charges become a motionless 10-dimensional
quantum intrinsic space. Its corresponding 32-component fermions in the spinor
representation possess a maximal gauge symmetry SO(32). As a consequence, a
maximally symmetric minimal unification model SO(32) containing three families
in ten dimensional quantum space-time is naturally obtained by choosing a
suitable Majorana-Weyl spinor structure into which quarks and leptons are
directly embedded. Both resulting symmetry and dimensions coincide with the
ones of type I string and heterotic string SO(32) in string theory.Comment: 17 pages, RevTex, published version with minor typos correcte
^{59}Co NMR evidence for charge ordering below T_{CO}\sim 51 K in Na_{0.5}CoO_2
The CoO layers in sodium-cobaltates NaCoO may be viewed as
a spin triangular-lattice doped with charge carriers. The underlying
physics of the cobaltates is very similar to that of the high cuprates.
We will present unequivocal Co NMR evidence that below ,
the insulating ground state of the itinerant antiferromagnet
NaCoO () is induced by charge ordering.Comment: Phys. Rev. Lett. 100 (2008), in press. 4 figure
Spectroscopic applications and frequency locking of THz photomixing with distributed-Bragg-reflector diode lasers in low-temperature-grown GaAs
A compact, narrow-linewidth, tunable source of THz radiation has been developed for spectroscopy and other high-resolution applications. Distributed-Bragg-reflector (DBR) diode lasers at 850 nm are used to pump a low-temperature-grown GaAs photomixer. Resonant optical feedback is employed to stabilize the center frequencies and narrow the linewidths of the DBR lasers. The heterodyne linewidth full-width at half-maximum of two optically locked DBR lasers is 50 kHz on the 20 ms time scale and 2 MHz over 10 s; free-running DBR lasers have linewidths of 40 and 90 MHz on such time scales. This instrument has been used to obtain rotational spectra of acetonitrile (CH3CN) at 313 GHz. Detection limits of 1 × 10^–4 Hz^1/2 (noise/total power) have been achieved, with the noise floor dominated by the detector's noise equivalent power
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