| 1. |
- Baek, Seung Ki
(author)
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Cluster Monte Carlo study of magnetic dipoles
- 2011
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In: Journal of the Korean Physical Society. - : Korean Physical Society. - 0374-4884 .- 1976-8524. ; 59:3, s. 2381-2386
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Journal article (peer-reviewed)abstract
- We implement a cluster-update Monte Carlo algorithm to simulate magnetic dipoles of the XY-spin type, confined in the two-dimensional plane. The long-range character and anisotropy in the dipole interaction are handled by the Luijten-Bl\"ote algorithm and the Dotsenko-Selke-Talapov algorithm, respectively. We have checked performance of this algorithm in comparison to the Metropolis algorithm and found that it equilibrates the system faster in terms of the number of flipped spins, although the overall computational complexity of the problem remains the same.
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| 2. |
- Benyattou, T., et al.
(author)
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Optical Bloch waves studied by near optical field microscopy
- 2005
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In: Journal of the Korean Physical Society. - 0374-4884 .- 1976-8524. ; 47, s. S72-S75
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Journal article (peer-reviewed)abstract
- Photonic bandgap structures are very promising for the integration of optical function at the nanoscale level and particularly 2D structures perforated on a slab waveguide. In this context, photonic crystal waveguides obtained by removing rows of holes in the periodic structure are very interesting. We will present here, results of near field optical microscopy conducted on PCW. With a Fourier transform analysis of the image, we can image the Bloch waves propagating in the waveguide. The results are compared to FDTD simulations and we will show that the images obtained correspond to the electric field. Such result allows us to study the interaction of the optical tip with the electromagnetic field. 2D FDTD simulations of 1D photonic crystal interaction with a SNOM tip is presented. The results obtained confirm that the SNOM signal is mainly related to the electric field.
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| 3. |
- Bevilacqua, Riccardo, et al.
(author)
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Light-Ion Production in the Interaction of 175 MeV Neutrons with Iron and Bismuth
- 2011
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In: Journal of the Korean Physical Society. - : Korean Physical Society. - 0374-4884 .- 1976-8524. ; 59:2, s. 1701-1704
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Journal article (peer-reviewed)abstract
- We have measured double-differential (angle and energy) cross sections for light-ion (p, d, t, (3)He, and a) production in the interaction of quasi-monoenergetic 175 MeV neutrons with iron and bismuth. Measurements have been performed at the The Svedberg Laboratory, Uppsala (Sweden), using the Medley setup which allows low-energy thresholds and wide energy and angular ranges. Medley is a spectrometer system consisting of eight three-element telescopes placed at angles from 20 degrees to 160 degrees, in steps of 20 degrees. Each telescope is composed of two silicon surface barrier detectors and a CsI(Tl) scintillator, to perform particle identification, fully stop the produced light-ions and measure their kinetic energy. The time-of-flight was used to reduce the contribution from the low energy tail in the accepted incident neutron spectrum. We report double-differential production cross sections for protons, deuterons, tritons, (3)He and alpha particles and compare them with model calculations with TALYS-1.2.
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| 4. |
- Choi, Y. W., et al.
(author)
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Ordered Phases in Fe-Si Alloys : A First-Principles Study
- 2018
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In: Journal of the Korean Physical Society. - : The Korean Physical Society. - 0374-4884 .- 1976-8524. ; 72:6, s. 737-740
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Journal article (peer-reviewed)abstract
- It is known that the formation of ordered phases causes the brittleness of electrical steels. We employed first-principles method in order to examine the possibility of the ordered-phases formation in Fe-Si alloys. It is found that the D03-like ordered configuration is most stable among other atomic configurations in the ferromagnetic state. In the paramagnetic state, for low Si concentration, the stability of the ordered configurations is comparable to that of disordered ones. However, as Si content increases, the B2 ordered phase as well as the D03 phase becomes more stable than the disordered ones.
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| 5. |
- Furuta, T., et al.
(author)
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Spin-injection dynamics and effects of spin relaxation in self-assembled quantum dots of CdSe
- 2008
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In: Journal of the Korean Physical Society. - 0374-4884 .- 1976-8524. ; 53, s. 163-166
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Journal article (peer-reviewed)abstract
- We study the spin injection dynamics and the effects of spin relaxation in self-assembled quantum dots (QDs) of CdSe coupled with a diluted magnetic semiconductor (DMS) layer of ZnMnSe, where spin-polarized excitons can be injected from the DMS into the QDs because of the potential difference. The degree of circular polarization, $P$, of excitonic photoluminescence (PL) at 5 T in the coupled QDs shows a rapid increase with increasing delay time after a linearly polarized pulse excitation, indicating the spin-injection dynamics. The $P$ value tends to decay gradually because of the exciton-spin relaxation in the QDs after the spin injection. The spin-polarized excitons in the QD ensemble migrate simultaneously from QDs with higher exciton energies to those with lower exciton energies. This inter-dot transfer of excitons also affects the $P$ value in the lower energy region of the QD-emission band because the excitons lose their spin polarizations due to the spin relaxation in the dots during the migration. The detailed analysis for the exciton-spin transfer is presented in a coupled QD system after spin injection.
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| 6. |
- Hakim, M. A., et al.
(author)
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Dilution of the magnetic moment of Fe by Cr for Fe73.5-xCrxCu1Nb3Si13.5B9 and the field-cooled and zero-field-cooled behavior for higher Cr content
- 2008
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In: Journal of the Korean Physical Society. - 0374-4884 .- 1976-8524. ; 53:2, s. 766-771
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Journal article (peer-reviewed)abstract
- The temperature and the field dependences of the magnetization have been measured for Fe73.5-xCrxCu1Nb3Si13.5B9 (0 < ;= x < ;= 17.5) prepared by using a melt spin technique. The temperature dependence of the magnetization in the range of 5 to 300 K with an applied field of I Tesla for all the compositions follows the relaxation M(T) = M-0(1 - BT3/2 - CT5/2), which is indicative of the presence of a spin wave excitation. The saturation magnetizations at 5 and 300 K decrease linearly with Cr concentration for the entire composition range, which indicates that a simple dilution of the Fe moment takes place due to Cr substitution. The field-cooled (FC) and the zero-field-cooled (ZFC) magnetizations measured with an applied field of 1 Oe show divergences for x = 10, 12.5, 15 and 17.5, which may be attributed to the magnetic hardening at low temperatures.
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| 7. |
- Hambsch, F. -J, et al.
(author)
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Investigation of the Fission Process at IRMM
- 2011
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In: Journal of the Korean Physical Society. - : Korean Physical Society. - 0374-4884 .- 1976-8524. ; 59:2, s. 1654-1659
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Journal article (peer-reviewed)abstract
- The investigation of the fission process is and has been a major undertaking at IRMM. The most recent investigations concerned the reaction (234)U(n,f) and (238)U(n,f) around vibrational resonances at the barrier of the fission cross-section. Furthermore prompt neutron emission of (252)Cf(SF) has been investigated understanding for the first time the prompt neutron multiplicity as a function of total kinetic energy (TKE). Theoretical modelling of reaction cross sections as well as prompt neutron multiplicity and spectra has been performed using the experimental data as input parameters. Also instrument developments for correlation measurements of fission fragment properties has been pursued in recent years with the time-of-flight spectrometer VERDI and detectors for prompt fission gamma-ray.
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| 8. |
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| 9. |
- Hirayama, S., et al.
(author)
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Light-ion Production from a Thin Silicon Target Bombarded by 175 MeV Quasi Mono-energetic Neutrons
- 2011
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In: Journal of the Korean Physical Society. - : Korean Physical Society. - 0374-4884 .- 1976-8524. ; 59:2, s. 1447-1450
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Journal article (peer-reviewed)abstract
- Double-differential production yields of light ions (p, d, t, (3)He, and alpha) from a thin silicon target induced by 175 MeV quasi mono-energetic neutrons were measured using the MEDLEY setup at the The Svedberg Laboratory (TSL) in Uppsala in order to benchmark evaluated nuclear data and nuclear reaction models. The MEDLEY is a conventional spectrometer system which consists of eight counter telescopes. Each telescope is composed of two silicon surface barrier detectors as the Delta E detectors and a CsI(Tl) scintillator as the E detector for particle identification. The telescopes are placed at angles from 20 degrees to 160 degrees in steps of 20 degrees. The measured double-differential yields of light ions are compared with PHITS calculations using the following nuclear reaction options: the high-energy nuclear data library (JENDL/HE-2007), the quantum molecular dynamics (QMD) model, and the intra-nuclear cascade (INC) model.
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| 10. |
- Holme, Petter
(author)
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Local symmetries in complex networks
- 2007
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In: Journal of the Korean Physical Society. - 0374-4884 .- 1976-8524. ; 50:1, s. 300-303
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Journal article (peer-reviewed)abstract
- Symmetry-invariance to certain operators-is a fundamental concept in many branches of physics. We propose ways to measure symmetric properties of vertices, and their surroundings, in networks. To be stable to the randomness inherent in many complex networks, we consider measures that are continuous rather than dichotomous. The main operator we suggest is permutations of paths of a certain length leading out from a vertex. If these paths are more similar (in some sense) than expected, the vertex is a local center of symmetry in the network. We discuss different precise definitions based on this idea and give examples how different symmetry coefficients can be applied to protein interaction networks.
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