• Analytical Science and Technology
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• v.27 no.6
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• pp.314-320
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• 2014

$La_{2-x}(MoO_4)_3:Er^{3+}/Yb^{3+}$ particles with doping concentrations of $Er^{3+}$ and $Yb^{3+}$ ($x=Er^{3+}+Yb^{3+}$, $Er^{3+}$=0.05, 0.1, 0.2 and $Yb^{3+}$ = 0.2, 0.45) were successfully prepared by the microwave-modified sol-gel method, and the upconversion photoluminescence properties were investigated. Well-crystallized particles, formed after heat-treatment at $900^{\circ}C$ for 16 h, showed a fine and homogeneous morphology with particle sizes of $2-5{\mu}m$. Under excitation at 980 nm, $La_{1.7}(MoO_4)_3:Er_{0.1}Yb_{0.2}$ and $La_{1.5}(MoO_4)_3:Er_{0.05}Yb_{0.45}$ particles exhibited a strong 525 nm emission band, a weak 550 nm emission band in the green region, and a very weak 655 nm emission band in the red region. The Raman spectra of the doped particles indicated the presence of strong peaks at higher frequencies of 752, 846, 922, 1358 and $1435cm^{-1}$ and lower frequency of $314cm^{-1}$ induced by the disorder of the $[MoO_4]^{2-}$ groups with the incorporation of the $Er^{3+}$ and $Yb^{3+}$ elements into the crystal lattice or by a new phase formation.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.26 no.2
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• pp.108-120
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• 2022

We considered qualitative behaviour of the generalization of Einstein's model of Brownian motion when the key parameter of the time interval of free jump degenerates. Fluids will be characterised by number of particles per unit volume (density of fluid) at point of observation. Degeneration of the phenomenon manifests in two scenarios: a) flow of the fluid, which is highly dispersing like a non-dense gas and b) flow of fluid far away from the source of flow, when the velocity of the flow is incomparably smaller than the gradient of the density. First, we will show that both types of flows can be modeled using the Einstein paradigm. We will investigate the question: What features will particle flow exhibit if the time interval of the free jump is inverse proportional to the density and its gradient ? We will show that in this scenario, the flow exhibits localization property, namely: if at some moment of time t₀ in the region, the gradient of the density or density itself is equal to zero, then for some T during time interval [t₀, t₀ + T] there is no flow in the region. This directly links to Barenblatt's finite speed of propagation property for the degenerate equation. The method of the proof is very different from Barenblatt's method and based on the application of Ladyzhenskaya - De Giorgi iterative scheme and Vespri - Tedeev technique. From PDE point of view it assumed that solution exists in appropriate Sobolev type of space.

• Parasites, Hosts and Diseases
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• v.48 no.4
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• pp.291-295
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• 2010

The onset, severity, and ultimate outcome of malaria infection are influenced by parasite-expressed virulence factors and individual host responses to these determinants, In both humans and mice, liver injury is involved after parasite entry, which persists until the erythrocyte stage after infection with the fatal strain Plasmodium falciparum (Pf), Hepatocyte growth factor (HGF) has strong anti-apoptotic effects in various kinds of cells, and also has diverse metabolic functions. In this work, Pf-subtilisin-like protease 2 (Pf-Sub2) 5' untranslated region (UTR) was analyzed and its transcriptional activity was estimated by luciferase expression. Fourteen TATA boxes were observed but only one Oct-1 and c-Myb were done. In addition, host HGF interaction with Pf-Sub2 was evaluated by co-transfection of HGF- and Pf-Sub2-cloned vector. Interestingly, -1,422/+12 UTR exhibited the strongest luciferase activity but -329 to + 12 UTR did not exhibit luciferase activity. Moreover, as compared with the control of unexpressed HGF, the HGF protein suppressed luciferase expression driven by the 5' untranslated region of the Pf-Sub2 promoter. Taken together, it is suggested that HGF controls and interacts with the promoter region of the Pf-Sub2 gene.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.131-135
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• 2004

The $H_2S\;(2_{2,0} - 2_{1,1})$ line emission is observed to be strongly localized toward Sgr B2(M), and emissions from other positions in the more extended SgrB2 region are almost negligible. $H_2S$ is thought to form effectively by the passage of the C-type shocks but to be quickly transformed to $SO_2$ or other sulfur species (Pineau des Forets et al. 1993). Such a shock may have enhanced the $H_2S$ abundance in Sgr B2(M), where massive star formation is taking place. But the negligible emission of $H_2S$ from other observed positions may indicate that these positions have not been affected by shocks enough to produce $H_2S$, or if they have experienced shocks, $H_2S$ may have transformed already to other sulfur-containing species. The $SO_2\;22_{2,20} - 22_{1,21}$ line was also observed to be detectable only toward the (M) position. The line intensity ratios of these two molecules appear to be very similar at Sgr B2(M) and IRAS 16239-2422, where the latter is a region of low-mass star formation. This may suggest that the shock environment in these two star-forming regions is similar and that the shock chemistry also proceeds in a similar fashion in these two different regions, if we accept shock formation of these two species.

• YAKHAK HOEJI
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• v.23 no.3_4
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• pp.129-132
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• 1979

The ORD and CD for hyoscine-N-butylbromide present curves of negative Cotton effect in 190-250nm region. The values of .alpha./sub 232/ .alpha./sub 208/, vertical bar .alpha./sub 232/ vertical bar + vertical bar .alpha./sub 208/ and .theta./sub 221.5/ have linearities in the range of lower concentration (hyoscine-N-butylbromide 0.01-0.1w/v%). It is possible to determine the optical purity of hyoseine-N-butylbromide by using these linearities. This experiment is extremely simple and less time-consuming than other methods for estimating optical purity.

• Journal of the Korean Magnetics Society
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• v.15 no.1
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• pp.12-16
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• 2005

The $Fe_{87}Zr_{7}B_{6}$ amorphous alloy after neutron irradiation are studied hysteresis loop and complex permeability measurements. The total integration fluence of fast neutrons is varied from $1.92{\times}10^{14}$ to $4.85{\times}10^{16}n_{f1}cm^{-2}$. After neutron irradiation, the imaginary part of complex permeability in low frequency region decreased due to the decrease of wall motion, but the permeability in high frequency region increased due to the enhancement of rotational magnetization. The measurement of hysteresis loop showed the increase of magnetic softness, related to rotational magnetization, but saturation magnetization was decreased in neutron irradiation sample.

• Korean Journal of Materials Research
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• v.29 no.8
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• pp.463-468
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• 2019

The electrical and interfacial properties of $HfO_2/Al_2O_3$ and $Al_2O_3/HfO_2$ dielectrics on AlN/p-Ge interface prepared by thermal atomic layer deposition are investigated by capacitance-voltage(C-V) and current-voltage(I-V) measurements. In the C-V measurements, humps related to mid-gap states are observed when the ac frequency is below 100 kHz, revealing lower mid-gap states for the $HfO_2/Al_2O_3$ sample. Higher frequency dispersion in the inversion region is observed for the $Al_2O_3/HfO_2$ sample, indicating the presence of slow interface states A higher interface trap density calculated from the high-low frequency method is observed for the $Al_2O_3/HfO_2$ sample. The parallel conductance method, applied to the accumulation region, shows border traps at 0.3~0.32 eV for the $Al_2O_3/HfO_2$ sample, which are not observed for the $Al_2O_3/HfO_2$ sample. I-V measurements show a reduction of leakage current of about three orders of magnitude for the $HfO_2/Al_2O_3$ sample. Using the Fowler-Nordheim emission, the barrier height is calculated and found to be about 1.08 eV for the $HfO_2/Al_2O_3$ sample. Based on these results, it is suggested that $HfO_2/Al_2O_3$ is a better dielectric stack than $Al_2O_3/HfO_2$ on AlN/p-Ge interface.

• Journal of IKEEE
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• v.25 no.2
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• pp.344-349
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• 2021

This paper proposes a structure in which Trench SiO₂ is grown inside of Super Junction IGBT P-Pillar. When observing the electric field in 3D, we checked the region where the electric field have not affected inside of the P-Pillar. The pillar region's portion resistance is varied by the breakdown voltage and size of each pillar, which reduces the size by growing SiO₂ after trenching has no field effect inside of that. At 4.5kV the same breakdown voltage, it was confirmed that the On-state voltage drop improved by about 58%, 19% compared to Field Stop IGBT and conventional Super Junction IGBT.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3268-3276
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• 2023

The practice of identifying the potential zones for mineral exploration in a speedy and low-cost method includes the use of satellite imagery analysis as a part of remote sensing techniques. It is challenging to explore the iron mineralization of a region through conventional methods which are a time-consuming process. The current study utilizes the Hyperion satellite imagery for mapping the iron mineralization and associated geological features in the Irikkur region, Kannur, Kerala. Along with the remote sensing results, the field study and laboratory-based analysis were conducted to retrieve the ground truth point and geochemical proportion to verify the iron ore mineralization. The MC simulation showed for shielding properties indicate an increase in the linear attenuation coefficient with raising the Fe₂O₃+SiO₂ concentrations in the investigated rocks where it is varied at 0.662 MeV in the range 0.190 cm^-1 - 0.222 cm^-1 with rising the Fe₂O₃+SiO₂ content from 57.86 wt% to 71.15 wt%. The analysis also revealed that when the γ-ray energy increased from 0.221 MeV to 2.506 MeV, sample 1 had the largest linear attenuation coefficient, ranging from 9.33 cm1 to 0.12 cm^-1. Charnockite rocks were found to have exceptional shielding qualities, making them an excellent natural choice for radiation shielding applications.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.203-205
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• 1999

분산 가상환경(DVE)이 대규모가 되어감에 따라, 고려해야 할 중요한 사항중의 하나는 확장성이다. DVE에 확장성을 지원하기 위한 여러 접근 방법 중의 하나는 region 분할 방법이다. 대부분의 DVE 시스템에서는 region은 분리되어 있으며 이웃한 region의 사용자들 사이의 상호작용이 지원된다. 하지만 사용자들은 항상 자신이 관심을 가지고 있는 이웃 region들 안의 모든 사용자 상태 정보를 알아야 한다. 이것은 region간 상호작용을 하는 사용자들에게 통신에 따른 부하가 많이 걸리게 되며 따라서 시스템 확장성이 떨어지게 된다. 본 연구에서는 region 관리자가 현재 region안의 사용자들에 대한 관심도가 높은 이웃 region안의 사용자들의 일부만 선택한다. 이를 통해 region안의 사용자들은 이웃 region으로부터 모든 갱신 메시지를 받지 않아도 된다. 본 연구를 통해 DVE 시스템은 확장성 있는 region안에서의 상호작용뿐만 아니라 region간 상호작용을 지원할 수 있다.