State Academy of science

Pyongyang, South Korea

State Academy of science

Pyongyang, South Korea

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Ri M.-H.,State Academy of science | Zhang P.,CAS Academy of Mathematics and Systems Science | Zhang Z.,Peking University
Journal of Mathematical Fluid Mechanics | Year: 2016

We prove global well-posedness for instationary Navier–Stokes equations with initial data in Besov space (Formula presented.) in whole and half space, and bounded domains of (Formula presented.) , (Formula presented.). To this end, we prove maximal (Formula presented.) -regularity of the sectorial operators in some Banach spaces and, in particular, maximal (Formula presented.) -regularity of the Stokes operator in little Nikolskii spaces (Formula presented.) , (Formula presented.) , which are of independent significance. Then, based on the maximal regularity results and (Formula presented.) estimates of the Stokes semigroups, we prove global well-posedness for Navier–Stokes equations under smallness condition on (Formula presented.) via a fixed point argument using Banach fixed point theorem. © 2016, Springer International Publishing.

PubMed | China Earthquake Administration, Birkbeck, University of London, Environmental Education Media Project, State Academy of Science and 3 more.
Type: Journal Article | Journal: Science advances | Year: 2017

Paektu volcano (Changbaishan) is a rhyolitic caldera that straddles the border between the Democratic Peoples Republic of Korea and China. Its most recent large eruption was the Millennium Eruption (ME; 23 km

Park H.,State Academy of science | Zhai M.,CAS Institute of Geology and Geophysics | Yang J.,State Academy of science | Peng P.,CAS Institute of Geology and Geophysics | And 5 more authors.
Yanshi Xuebao/Acta Petrologica Sinica | Year: 2016

The relationship of the Pyongnam basin with other basins in the Eastern North China Craton (Sino-Korean Craton) is in debating; and the deposition age is one key to solve this. The strata in the Pyongnam basin are mainly composed of the Sangwon Supergroup, which comprises the Jikhyon Group, the Sadangu Group, the Muckchon Group, the Myoransan Group and the Yontan Group from bottom to up. The Jikhyon Group is the lowermost formation and comprises of mainly terrestrial clastic sediments. Detrital zircons were separated from the clastic rocks of the Jikhyon Group of both the ' north-type ' and ' south-type ' strata of the Pyongnam basin, and their LA-ICP-MS U-Pb ages constrain the maximum deposition age to be 1100Ma. It further suggests that there are no differences either in deposition age or provenance between the so-called ' north-type ' and ' south-type ' strata. As the mafic sills in the Muckchon Group were intruded at ∼900Ma, we suggest that the majority of the Sangwon Supergroup was deposited at 1000 ∼900Ma, with the Yontan Group to be slightly younger. This indicates that the Pyongnam basin is contemporary with those in the Xu-Huai and Lv-Da basins. The variation of δ13C values of the carbonate samples from the Sangwon Supergroup shows a distinct negative drifting(δ13C value as low as-6‰ ∼-5‰) in the Mukchon Group. As the mafic sills in the Mukchon Group were emplaced at ∼900Ma, we suggest that this negative drifting of δ13C values happened slightly older than ∼ 900Ma, and is possibly related to a coeval magmatic event.

Kim K.-H.,State Academy of science | Yurkin M.A.,Novosibirsk State University
Optics Express | Year: 2015

We develop the time-domain discrete dipole approximation (DDA), describing the temporal evolution of electric field in plasmonic nanostructures. The main equation is obtained by taking the inverse Fourier transform of the Taylor expansion of the frequency-domain DDA in terms of frequency deviation from the central frequency. Thus we assume that incident wavefronts of different frequencies accumulate relatively small phase difference when passing the particle. This assumption is always valid for nanoparticles much smaller than the wavelength. Being the time-domain method, the proposed approach also requires an analytic frequency dependence of electric permittivity, e.g. The Drude model. We present numerical results of application of the time-domain DDA to silver nanosphere, rod, and disk, which agree well with that obtained with its frequency-domain counterpart and the finite-difference time-domain method. Moreover, the time-domain DDA is the fastest of the three methods for incident pulses of several-femtoseconds width. Thus, it can effectively be applied for modeling the temporal responses of plasmonic nanostructures. © 2015 Optical Society of America.

Ryu M.,CAS Institute of Microbiology | Ryu M.,University of Chinese Academy of Sciences | Ryu M.,State Academy of science | Chen Y.,CAS Institute of Microbiology | And 15 more authors.
PLoS ONE | Year: 2011

Structurally, Group 1 LILR (Leukocyte Immunogloblin (Ig)-Like Receptor, also known as Ig-like transcripts, ILT; Leukocyte Ig-like receptor, LIR; and CD85) members are very similar in terms of the HLAIs (human leukocyte antigen class I molecules) binding region and were hypothesized that they all bind to HLAIs. As one of the Group 1 LILRs, LILRA3 is the only secretory LILR and may greatly control the inhibitory immune response induced by LILRB1, LILRB2, and other HLA-binding LILR molecules like LILRA1. Nevertheless, little was known about the binding of LILRA3 to HLAIs. In this report, we present the crystal structure of the LILRA3 domain 1 (D1) and evaluate the D1 and D1D2 (domain 1 and domain 2) binding to classical and non-classical HLAIs using BIAcore® surface plasmon resonance analysis (SPR). We found that LILRA3 binds both classical HLA-A*0201 and non-classical HLA-G1 but with reduced affinities compared to either LILRB1 or LILRB2. The polymorphic amino acids and the LILRA3 D1 structure support this notion. © 2011 Ryu et al.

Kim K.-H.,Max Born Institute For Nichtlineare Optik Und Kurzzeitspektroskopie | Kim K.-H.,State Academy of science | Griebner U.,Max Born Institute For Nichtlineare Optik Und Kurzzeitspektroskopie | Herrmann J.,Max Born Institute For Nichtlineare Optik Und Kurzzeitspektroskopie
Optics Express | Year: 2012

We theoretically study femtosecond pulse generation by passive mode-locking of semiconductor disk lasers operating in the blue spectral range using metal nanocomposites as slow saturable absorbers. By using the relation for the nonlinear dielectric response of a layer of silica glass doped with spherical silver nanoparticles and the master equation for modelocking we investigate the dynamics of pulse formation and the achievable pulse parameters and predict the generation of pulses as short as 50 fs at 420 nm in such lasers. ©2012 Optical Society of America.

Ryo H.-S.,Kim Il Sung University | Ryo I.-G.,State Academy of Science
Applied Physics A: Materials Science and Processing | Year: 2016

In this study, a generalized inverse-pole-figure (IPF) method has been suggested to analyze domain switching in polycrystalline ferroelectrics including composition of morphotropic phase boundary (MPB). Using the generalized IPF method, saturated domain orientation textures of single-phase polycrystalline ferroelectrics with tetragonal and rhombohedral symmetry have been analytically calculated and the results have been confirmed by comparison with the results from preceding studies. In addition, saturated domain orientation textures near MPBs of different multiple-phase polycrystalline ferroelectrics have been also analytically calculated. The results show that the generalized IPF method is an efficient method to analyze not only domain switching of single-phase polycrystalline ferroelectrics but also MPB of multiple-phase polycrystalline ferroelectrics. © 2016, Springer-Verlag Berlin Heidelberg.

Kim K.-H.,State Academy of science | Choe S.-H.,State Academy of science
Plasmonics | Year: 2016

We present a theoretical approach for calculating the ultrafast nonlinear optical responses of dielectric composite materials containing metal nanoparticles with different sizes and shapes, taking silica glasses doped with silver nanospheres and nanorods. The approach is based on the model for nonlinear responses of metal nanoparticles combined with time-domain discrete dipole approximation for total field and the effective medium approximation. We numerically study the dependencies of the nonlinear transmittance of those composite films on several parameters such as sizes and aspect ratios of metal nanoparticles, pulse fluences and wavelengths of pump. © 2016 Springer Science+Business Media New York

We develop a theoretical model for the nondegenerate nonlinear optical susceptibility of dielectric composite materials containing metal nanoparticles. The model is based on the theory of transient nonlinear response of metal nanoparticles in combination with the effective medium approximation and the discrete dipole approximation. Its validity is confirmed by comparison with a preceding experimental result. Through numerical simulations, we demonstrate that for off-plasmon-resonant pumping the imaginary part of nondegenerate third-order nonlinear susceptibility becomes negative over a wide spectral range of signal. We additionally show the saturation effect of nondegenerate susceptibility depending on pump intensity and wavelength. © 2013 Astro Ltd.

Kim K.-H.,State Academy of science | Kim S.-H.,State Academy of science | Bae M.-C.,State Academy of science
Applied Optics | Year: 2015

We demonstrate that pronounced Fano resonance can be obtained by dipole-hexapole coupling in a χ-shaped plasmonic nanostructure. The confined local field in the vicinity of dipole-resonant nanorods excites and coherently couples to the hexapolar mode in the rod perpendicular to the polarization direction of the incident wave, leading to strong Fano resonance. By using the discrete dipole approximation, we numerically investigate the behavior of Fano resonance by dipole-hexapole coupling in the plasmonic nanostructure. We obtain the parameters relevant to Fano resonance by fitting the coupled oscillator model equation to the calculated extinction data and investigate their dependencies on the structural parameters. The results demonstrate the possibility of obtaining high-contrast Fano resonance with narrow features by using this plasmonic nanostructure, which has potential applications for highly sensitive biological sensing, low-loss metamaterials, and others. © 2015 Optical Society of America.

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