• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1313-1318
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• 2006

The mechanism fur the surface film formation was studied by in situ Atomic Force Microscopy (AFM) observation of a highly oriented pyrolytic graphite (HOPG) basal plane surface during cyclic voltammetry at a slow scan-rate of 0.5 mV $s^{-1}$ in 1 moi $dm^{-3}$ (M) $LiPF_6$ dissolved in a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC). Decomposition of the electrolyte solution began at a potential around 2.15 V vs. $Li^+$/Li on step edges. In the potential range 0.95-0.8 V vs. $Li^+$/Li, flat areas (hill-like structures) and large swelling appeared on the surface. It is considered that these two features were formed by the intercalation of solvated lithium ions and their decomposition beneath the surface, respectively. At potentials more negative than 0.80 V vs. $Li^+$/Li, particle-like precipitates appeared on the basal plane surface. After the first cycle, the thickness of the precipitate layer was 30 nm. The precipitates were considered to be decomposition of the lithium salt ($LiPF_6$) and solvent molecules (EC and DEC), and to have an important role in suppressing further solvent decomposition on the basal plane.

• Journal of Korean Society of Steel Construction
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• v.20 no.5
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• pp.675-681
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• 2008

This study introduced a new steel-jacketing method to retrofit RC columns. It also estimated the performance of steel-jacketed concrete cylinders. Twelve concrete cylinders were fabricated with varying steel jacket thicknesses of 1.0, 1.5, and 2.0 mm. Lateral confining pressure was applied with three clamps and the performance of plain concrete cylinders was compared with that of steel-jacketed cylinders. Steel jacket proved to be effective in increasing the strength of the cylinder. Finally, Li's constitutive model was compared with that of the experimentalresults. However, Li's model showed incongruity in Region II, which indicates the region after the yield of steel jackets. Therefore, the modified value of n was used for the region and the model showed a good agreement.

• Journal of Radiation Protection and Research
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• v.15 no.2
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• pp.57-65
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• 1990

Newly developed LiF(Mg, Cu, Na, Si) thermoluminescence phosphors sealed in a plastic capsules (32mm dia., 0.9mm wall thickness) were used for in-phantom dosimetry of $^{60}Co$ $\gamma$-irradiation. The absorbed doses in water were determined by applying the general cavity theory to the absorbed dose in TLD cavity, which was computed from exposure. The absorbed doses at various sites in the water-phantom were measured by LiF(Mg, Cu, Na, Si) TLD and compared with doses obtained by the ionization method. Both results were consistent within the experimental fluctuation$({\pm}3%)$ Central axis percentage depth doses and phantom-air ratios measured by LiF(Mg. Cu, Na, Si) TLD showed good agreement with the published values[Br. J. Radiology, Suppl. 17(1983)].

• Journal of Microbiology and Biotechnology
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• v.33 no.12
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• pp.1657-1670
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• 2023

This study aimed to evaluate the effects of Limosilactobacillus fermentum and Lactiplantibacillus plantarum isolated from human feces coordinating with inulin on the composition of gut microbiota and metabolic profiles in db/db mice. These supplements were administered to db/db mice for 12 weeks. The results showed that the Lactobacillaceae coordinating with inulin group (LI) exhibited lower fasting blood glucose levels than the model control group (MC). Additionally, LI was found to enhance colon tissue and increase the levels of short-chain fatty acids. 16S rRNA sequencing revealed that the abundance of Corynebacterium and Proteus, which were significantly increased in the MC group compared with NC group, were significantly decreased by the treatment of LI that also restored the key genera of the Lachnospiraceae_NK4A136_group, Lachnoclostridium, Ruminococcus_gnavus_group, Desulfovibrio, and Lachnospiraceae_UCG-006. Untargeted metabolomics analysis showed that lotaustralin, 5-hydroxyindoleacetic acid, and 13(S)-HpODE were increased while L-phenylalanine and L-tryptophan were decreased in the MC group compared with the NC group. However, the intervention of LI reversed the levels of these metabolites in the intestine. Correlation analysis revealed that Lachnoclostridium and Ruminococcus_gnavus_group were negatively correlated with 5-hydroxyindoleacetic acid and 13(S)-HpODE, but positively correlated with L-tryptophan. 13(S)-HpODE was involved in the "linoleic acid metabolism". L-tryptophan and 5-hydroxyindoleacetic acid were involved in "tryptophan metabolism" and "serotonergic synapse". These findings suggest that LI may alleviate type 2 diabetes symptoms by modulating the abundance of Ruminococcus_gnavus_group and Lachnoclostridium to regulate the pathways of "linoleic acid metabolism", "serotonergic synapse", and" tryptophan metabolism". Our results provide new insights into prevention and treatment of type 2 diabetes.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.752-756
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• 2002

Green-emitting $Zn_2SiO_4:Mn$ phosphors for PDP(Plasma Display Panel) application were synthesized by colloidal seed-assisted spray pyrolysis process. The codoping with $Gd^{3+}/Li^+$, which replaces $Si^{4+}$ site in the willemite structure, was performed to improve the luminous properties of the $Zn_2SiO_4:Mn$ phosphors. The particles prepared by spray pyrolysis process using fumed silica colloidal solution had a spherical shape, small particle size, narrow size distribution, and non-aggregation characteristics. The $Gd^{3+}/Li^+$ codoping amount affected the luminous characteristics of $Zn_2SiO_4:Mn$ phosphors. The codoping with proper amounts of $Gd^{3+}/Li^+$ improved both the photoluminescence efficiency and decay time of $Zn_2SiO_4:Mn$ phosphor particles. In spray pyrolysis, the post-treatment temperature is another factor controlling the luminous performance of $Zn_2SiO_4:Mn$ phosphors. The $Zn_{1.9}SiO_4:Mn_{0.1}$ phosphor particles containing 0.1 mol% $Gd^{3+}/Li^+$ co-dopant had a 5% higher PL intensity than the commercial product and 5.7 ms decay time after post-treatment at $1,145^{\circ}C$.

• Journal of the Korean Electrochemical Society
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• v.14 no.3
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• pp.131-137
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• 2011

A simple and rapid electrochemical method for the quantitative analysis of $Mn^{2+}$ ion is demonstrated with a view to examine the $Mn^{2+}$ dissolution behavior of $LiMn_2O_4$. The method described herein is based on the oxidation reaction of $Mn^{2+}$ to $Mn^{4+}(MnO_2)$ in aqueous buffer solution. Under the optimum condition (pH 8.9 0.04 M $NH_3-NH_4Cl$ buffer solution and glassy carbon working electrode), the linear range of $5{\mu}M-100{\mu}M$ (0.275-5.5 ppm) [$Mn^{2+}$] is obtained for the Linear sweep voltammetry(LSV) and $0.2{\mu}M-10{\mu}M$ (0.011-0.55 ppm) [$Mn^{2+}$] for the differential pulse voltammetry (DPV), respectively. It is also noted that the oxidation reaction of $Mn^{2+}$ ion is reduced with increasing amount of the electrolyte ($LiPF_6$, EC, EMC) added to the measuring solution, which is found to be mainly due to $LiPF_6$ and EC rather than EMC.

• Journal of Sensor Science and Technology
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• v.8 no.5
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• pp.359-367
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• 1999

CsI(Li) single crystals doped with 0.02, 0.1, 0.2 and 0.3 mole% lithium as an activator were grown by Czochralski method. The lattice structure of grown CsI(Li) single crystal was bcc, its lattice constant was $4.568\;{\AA}$. The absorption edge of CsI(Li) single crystal was 245 nm, and the spectral range of luminescence was $300{\sim}600\;nm$, its maximum luminescence intensity appeared at 425 nm. The energy resolutions of CsI(Li) single crystal doped with 0.2 mole% lithium were 14.5% for $^{137}Cs$(662 keV), 11.4% for $^{54}Mn$(835 keV) and 17.7% and 7.9% for $^{22}Na$(511 keV and 1275 keV), respectively. The relation formula of $\gamma$-ray energy versus energy resolution was ln (FWHM%) = -0.893lnE + 8.456 and energy calibration formula was ${\log}E_r=1.455\;{\log}(ch.)-1.277$. The phosphorescence decay time of CsI(Li) crystal doped with 0.2 mole% lithium was 0.51 s at room temperature, and its time resolution measured by CFT(constant-fraction timing method) was 9.0 ns.

• Journal of the Korean Institute of Gas
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• v.5 no.4 s.16
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• pp.33-39
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• 2001

This paper was studied on corrosion behavior of absorption refrigeration systems using $LiBr-H_2O$ working fluids. In the various concentration of lithium bromide solution, polarization test of SS 400, Cu(C1220T-OL) and Al-Ni bronze is carried out. And the corrosion behavior of materials forming absorption refrigeration systems is investigated. The main results are as following: 1) As concentration of lithium bromide solution increases, polarization resistance of materials of each kinds is low. And open circuit potential becomes less noble, the corrosion current density is high drained 2) Open circuit potential of SS 400 is less noble than that of Cu and Al-Ni bronze, corrosion current density of SS5 400 is high drained than that of Cu and Al-Ni bronze. 3) Anodic polarization of Cu and Al-Ni bronze in $62\%$ LiBr solution continues the active state. that of Cu and Al-Ni bronze in the natural sea water maintains the active state and the critical current for passivation appears.

• Korean Journal of Materials Research
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• v.15 no.3
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• pp.155-160
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• 2005

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is very corrosive fir typical structural materials. So, it is essential to choose the optimum material f3r the process equipment handling molten salt. In this study, the corrosion behavior of Al-Y coated Haynes 263 in a molten salt of $LiCl-Li_2O$ under oxidation atmosphere was investigated at $650^{\circ}C$ for $72\~168$ hours. The corrosion rate of Al-Y coated Haynes 263 was low while that of bare Haynes 263 was high in a molten salt of $LiCl-Li_2O$. Al-Y coated Haynes 263 improved the corrosion resistance better than bare Haynes 263 alloy. An Al oxide layer acts as a protective film which Prohibits Penetration of oxygen. Corrosion Products were formed $Li(Ni,Co)O_2$ and $LiTiO_2$ on bare Haynes 263, but $LiAlO_2,\;Li_5Fe_5O_8\;and\;LiTiO_2$ on Al-Y coated Haynes 263.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2005.11a
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• pp.81-104
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• 2005

Accurate 3D models in urban areas are essential for a variety of applications, such as virtual visualization, CIS, and mobile communications. LiDAR(Light Detection and Ranging) is a relatively new technology for directly obtaining 3D points. Because Manual 3D data reconstruction from LiDAR data is very costly and time consuming, many researchs is focused on the automatic extraction of the useful data. In this paper, we classified ground and non-ground points data from LiDAR data by using filtering, and we reconstructed the DTM(Digital Terrain Model) using ground points data, buildings using nonground points data. After the reconstruction, we assessed the accuracy of the DTM and buildings. As a result of, DTM from LiDAR data were 0.16m and 0.59m in high raised apartments areas and low house areas respectively, and buildings were matched with the accuracy of a l/5,000 digital map.