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Pyongyang, North Korea

Kim Il-sung University, founded on 1 October 1946, is the first university built in North Korea. It is located on a 15 hectare campus in Pyongyang, the nation's capital. Along with the main academic buildings, the campus contains 10 separate offices, 50 laboratories, libraries, museums, a printing press, an R&D centre, dormitories and a hospital. The university is named in honor of Kim Il-sung, the founder of the Democratic People's Republic of Korea. Courses in the department of social science take 5 years, while those of the department of natural science take 6 years to complete. Wikipedia.

We theoretically study chirped four-wave mixing for VUV pulse generation in hollow-core photonic crystal fibers. We predict the generation of sub-10'fs VUV pulses with energy of up to hundreds of 'J by broad-band chirped idler pulses at 830'nm and MW pump pulses with narrow-band at 277'nm. The MW pump could be desirable to reduce the complexity of the laser system or use a high repetition rate laser system. The energy conversion efficiency from pump pulse to VUV pulse reaches to 30% . This generation can be realized in a kagome-lattice hollow-core PCF filled with noble gas of high pressure with core diameter less than 40''m, which would enable technically simple or highly efficient coupling to the fundamental mode of the fiber. © 2015 Astro Ltd. Source

Kim N.-C.,Wuhan University | Kim N.-C.,Kim Il Sung University | Li J.-B.,Wuhan University | Yang Z.-J.,Wuhan University | And 2 more authors.
Applied Physics Letters

We investigated the scattering property of a single plasmon interacting with two quantum dots coupled to one-dimensional surface plasmonic waveguide. We demonstrated that the transmission of a single plasmon could be switched on or off by adjusting spectral detuning and controlling spatial separation of the two quantum dots. These transport properties of the nanosystem could find the applications in plasmonic nanodevices and quantum information processing. © 2010 American Institute of Physics. Source

Metzler W.,University of Kassel | Yun C.H.,Kim Il Sung University
International Journal of Bifurcation and Chaos

We present a general method for generating continuous fractal interpolation surfaces by iterated function systems on an arbitrary data set over rectangular grids and estimate their Box-counting dimension. © 2010 World Scientific Publishing Company. Source

Kim Y.-S.,CAS Wuhan Institute of Hydrobiology | Kim Y.-S.,Kim Il Sung University | Ke F.,CAS Wuhan Institute of Hydrobiology | Lei X.-Y.,CAS Wuhan Institute of Hydrobiology | And 2 more authors.

Background: Envelope protein 53R was identified from frog Rana grylio virus (RGV), a member of the family Iridoviridae, and it plays an important role in the virus assembly. Although inhibition of iridovirus major capsid protein (MCP) by small hairpin RNAs (shRNAs) has been shown to cause resistance to viral infection in vitro, RNA interference (RNAi) to inhibit aquatic animal virus envelope protein gene product has not been reported. Methodology: We devised artificial microRNAs (amiRNAs) that target a viral envelope protein gene RGV 53R. By incorporating sequences encoding amiRNAs specific to 53R of RGV into pre-miRNA155 (pSM155) vectors, which use the backbone of natural miR-155 sequence and could intracellularly express 53R-targeted pre-amiRNAs. The pre-amiRNAs could be processed by the RNase III-like enzyme Dicer into 21-25 nt amiRNAs (amiR-53Rs) in fish cell lines. The levels of 53R expression were analyzed through real-time PCR and RGV virions assembly were observed by electronic microscopy in fish cells transfected with or without amiR-53Rs at 72 h of RGV infection. Conclusion/Significance: The results argue that viral envelope protein RGV 53R can be silenced and the virions assembly was deficient by amiR-53R-1, and further identified the first amiRNA of envelope protein gene from iridovirus that was able to cause resistance to virus infection in fish cells. The data demonstrate that the viral infection is efficiently suppressed (58%) by amiR-53R-1 targeting positon 36-57 of RGV 53R. Moreover, electron microscopic observations revealed virion assembly defect or reduced virions assembly capacity was closely correlated to expression of amiR-53R-1. Based on real time PCR of the Mx gene, we found no evidence of activation of IFN by amiR-53R-1. © 2010 Kim et al. Source

Drewes M.,TU Munich | Kang J.U.,Kim Il Sung University
Nuclear Physics B

We calculate the relaxation rate of a scalar field in a plasma of other scalars and fermions with gauge interactions using thermal quantum field theory. It yields the rate of cosmic reheating and thereby determines the temperature of the "hot big bang" in inflationary cosmology. The total rate originates from various processes, including decays and inverse decays as well as Landau damping by scatterings. It involves quantum statistical effects and off-shell transport. Its temperature dependence can be highly non-trivial, making it impossible to express the reheating temperature in terms of the model parameters in a simple way. We pay special attention to the temperature dependence of the phase space due to the modified dispersion relations in the plasma. We find that it can have a drastic effect on the efficiency of perturbative reheating, which depends on the way particles in the primordial plasma interact. For some interactions thermal masses can effectively close the phase space for the dominant dissipative processes and thereby impose an upper bound on the reheating temperature. In other cases they open up new channels of dissipation, hence increase the reheating temperature. At high temperatures we find that the universe can even be heated through couplings to fermions, which are often assumed to be negligible due to Pauli-blocking. These effects may also be relevant for baryogenesis, dark matter production, the fate of moduli and in scenarios of warm inflation. © 2013 Elsevier B.V. Source

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