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991.
When two-dimensional electrons are subjected to a very strong magnetic field, they are believed to form a triangular crystal. By a direct comparison with the exact wave function, we demonstrate that this crystal is not a simple Hartree-Fock crystal of electrons but an inherently quantum mechanical crystal characterized by a nonperturbative binding of quantized vortices to electrons. It is suggested that this has qualitative consequences for experiment. 相似文献
992.
Hasegawa M Aliu E Andringa S Aoki S Argyriades J Asakura K Ashie R Berns H Bhang H Blondel A Borghi S Bouchez J Burguet-Castell J Casper D Cavata C Cervera A Chen SM Cho KO Choi JH Dore U Espinal X Fechner M Fernandez E Fukuda Y Gomez-Cadenas J Gran R Hara T Hasegawa T Hayashi K Hayato Y Helmer RL Hill J Hiraide K Hosaka J Ichikawa AK Iinuma M Ikeda A Inagaki T Ishida T Ishihara K Ishii T Ishitsuka M Itow Y Iwashita T Jang HI Jeon EJ Jeong IS Joo KK Jover G Jung CK Kajita T Kameda J Kaneyuki K 《Physical review letters》2005,95(25):252301
We report the result from a search for charged-current coherent pion production induced by muon neutrinos with a mean energy of 1.3 GeV. The data are collected with a fully active scintillator detector in the K2K long-baseline neutrino oscillation experiment. No evidence for coherent pion production is observed, and an upper limit of is set on the cross section ratio of coherent pion production to the total charged-current interaction at 90% confidence level. This is the first experimental limit for coherent charged pion production in the energy region of a few GeV. 相似文献
993.
Rhee HS Oh SH Ko BJ Han DM Jeon BH Park H Moon HB Kim WS 《Experimental & molecular medicine》2003,35(3):160-166
The enzyme complex 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4-isomerase (3beta-HSD) is involved in the biosynthesis of all classes of active steroids. The expression of 3b-HSD in human uterine endometrium during the menstrual cycle and decidua was examined in an effort to understand its role during ova implantation. 3beta-HSD was weakly expressed in the glandular epithelium of the proliferative phase and moderately expressed in the glandular epithelium of secretory phase of the endometrium. In the decidua of the ectopic pregnancy, 3beta-HSD was strongly expressed. The human uterine endometrial 3beta-HSD was identified as being the same type as the placental 3beta-HSD by RT-PCR and sequence analysis. In addition to the expression of 3beta-HSD, P450scc was expressed in the decidua of the ectopic pregnancy. These results suggest that pregnenolone might be synthesized from cholesterol by P450scc de novo and then, it is converted to progesterone by 3beta-HSD in the uterine endometrium. The data implies that the endometrial 3beta-HSD can use not only the out-coming pregnenolone from the adrenal gland but also the self- made pregnenolone to produce progesterone. The de novo synthesis of progesterone in the endometrium might be a crucial factor for implantation and maintenance of pregnancy. 相似文献
994.
Jeon Y. Sloan I.H. Stephan E.P. Elschner J. 《Advances in Computational Mathematics》1997,7(4):547-571
We consider a fully discrete qualocation method for Symm’s integral equation. The method is that of Sloan and Burn (1992),
for which a complete analysis is available in the case of smooth curves. The convergence for smooth curves can be improved
by a subtraction of singularity (Jeon and Kimn, 1996). In this paper we extend these results for smooth boundaries to polygonal
boundaries. The analysis uses a mesh grading transformation method for Symm’s integral equation, as in Elschner and Graham
(1995) and Elschner and Stephan (1996), to overcome the singular behavior of solutions at corners.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
995.
Jean-Sébastien Gagnon François Fillion-Gourdeau Sangyong Jeon 《Acta Physica Hungarica A》2006,27(2-3):339-342
We use the full multiple scattering expansion of the retarded self-energy to obtain the gain and loss rates present in the Kadanoff-Baym relativistic transport equation. The rates we obtain include processes with any number of particles. As a first approximation, we only consider central cuts in the self-energies, but otherwise our results are general. We specialize to the case of scalar field theory to compare with lowest order results. The main application of this work is relativistic transport theory of very dense systems, such as the quark-gluon plasma or the early universe, where multi-particle interactions are important. 相似文献
996.
In this paper we propose an encryption/decryption technique of gray-level image information using an on-axis 2-f digital holographic
optical encrypting system with two-step phase-shifting method. This technique reduces the number of holograms in phase-shifting
digital holography and minimizes the setup of the encryption system more than multistep phase-shifting technique. We are able
to get the complete decrypted image by controlling the K-ratio which is defined as the reference beam intensity versus the object beam intensity. We remove the DC-term of the phase-shifting
digital hologram to reconstruct and decrypt the original image information. Simulation results show that the proposed method
can be used for encryption and decryption of a 256 gray-level image. Also, the result shows some errors of the decrypted image
according to K-ratio. 相似文献
997.
A. Mandelis R. Jeon A. Matvienko S. H. Abrams B. T. Amaechi 《The European physical journal. Special topics》2008,153(1):449-454
Recent trends in biothermophotonics of teeth are
presented. The presentation is centered on the development of clinical-level
frequency-domain photothermal radiometry and modulated luminescence to
address issues associated with the early diagnosis of demineralization
caries in human teeth. Biothermophotonic principles and applications to the
detection of the carious state in human teeth as embodied by laser
photothermal radiometry are presented and further supported by modulated
luminescence. The emphasis is on recent developments with regard to
abilities of these techniques to diagnose interproximal lesions between
teeth, etching with phosphoric acid and with an artificial demineralization
gel in order to simulate early demineralization, as well as demineralization
and remineralization of dental crown enamel and root dentin. These are
lesions which normally go undetected by X-ray radiographs. Comparisons with
X rays, Micro-Computed Tomography (μ-CT) and Transverse
Micro-Radiography (TMR) are discussed. A theoretical model involving coupled
diffuse photon density and thermal-wave fields is developed and applied to
frequency scans from demineralized artificial lesions to produce
quantitative values for optical and thermophysical parameters of teeth as
well as the thickness of the induced lesion. 相似文献
998.
Nonlinear optical materials of the type Zn
x
Cd1-x
Te single crystals, where x = 0.0, 0.2, 0.4, 0.6, 0.7, 0.8, and 1.0, have been grown by the Bridgman method, using a vertical furnace. We have investigated
the electro-optic (E-O) coefficient and refractive index of Zn
x
Cd1-x
Te single crystals at optical communication wavelength (1550 nm). In the case of CdTe crystal, the E-O coefficient was 15.5
× 10-12 m/V, which is the biggest among the E-O coefficients of Zn
x
Cd1-x
Te crystals. The E-O modulation signal was very big in low frequency range (DC-100kHz), but the signal amplitude became smaller
as we increased frequency above 100 kHz. We also found the acousto-optic modulation at CdTe single crystals. 相似文献
999.
We have enhanced color-rendering property of a blue light emitting diode (LED) pumped white LED with yellow emitting Y3Al5O12:Ce3+ (YAG:Ce) phosphor using addition of Pr and Tb as a co-activator and host lattice element, respectively. Pr3+ addition to YAG:Ce phosphor resulted in sharp emission peak at about 610 nm through 1D2→3H4 transition. And when Tb3+ substituted Y3+ sites, Ce3+ emission band shifted to a longer wavelength due to larger crystal field splitting. Y3Al5O12:Ce3+, Pr3+ and (Y1−xTbx)3Al5O12:Ce3+ phosphors were coated on blue LEDs to fabricate white LEDs, respectively, and their color-rendering indices (CRIs, Ra) were measured. As a consequence of the addition of Pr3+ or Tb3+, CRI of the white LEDs improved to be Ra=83 and 80, respectively. Especially, blue LED pumped (Y0.2Tb0.8)3Al5O12:Ce3+ white LED showed both strong luminescence and high color-rendering property. 相似文献
1000.
A new family of locally conservative, finite element methods for a rectangular mesh is introduced to solve second-order elliptic equations. Our approach is composed of generating PDE-adapted local basis and solving a global matrix system arising from a flux continuity equation. Quadratic and cubic elements are analyzed and optimal order error estimates measured in the energy norm are provided for elliptic equations. Next, this approach is exploited to approximate Stokes equations. Numerical results are presented for various examples including the lid driven-cavity problem. 相似文献