• Korean Journal of Materials Research
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• v.4 no.5
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• pp.556-565
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• 1994

Effects of Ag addition to 2090 and CP 276 Al-Li alloy systems on the microstructure and mechanical properties have been investigated. The addition of silver up to 0.16wt.% reduced the grain size of the alloys, and was responsible for the formation of finer and more uniform $\delta$'($AI_{3}Li$) and $T_{1}(AI_{2}CuLi$) precipitates in 2090 alloys, even though no variation of precipitates was found in CP 276 alloys. The addition of 0.16wt.% Ag improved the tensile strength of 2090 alloys about 40MPa with the expense of small reduction of percent elongation. However, the small addition of Ag to CP 276 containing Mg did not show any variation of tensile strength and elongation. The aging treatment of these alloys at $150^{\circ}C$ for 70 or 90 hours, depending on alloy systems, showed peak hardness value of about 92 $H_rB$.

• Journal of the Korean Society for Heat Treatment
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• v.4 no.3
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• pp.13-20
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• 1991

The present work was aimed to examine the variation of precipitations and mechanical properties by thermomechanical treatments (TMT) in Al-2.19 wt%Li and Al-2.0 wt%Li-0.11 wt%Zr alloys. This study was performed by TEM, SEM observation, DSC, electrical resistance measurement, hardness and tensile strength measurement. First peak of resistivity aged at $90^{\circ}C$ was caused by precipitation of ${\delta}^{\prime}$-precursor phase, and second peak was caused by precipitation of ${\delta}^{\prime}$ phase. According to this result, the precipitation process of Al-2.19 wt%Li alloy was as follow : $SSSS{\rightarrow}{\delta}^{\prime}$-precursor phase ${\rightarrow}{\delta}^{\prime}$ (Coherent ${\rightarrow}$ Semi-coherent) ${\rightarrow}{\delta}$. In a Al-2.0 wt%Li-0.11 wt%Zr ternary alloy, the first peak of resistivity was appeared at initial aging heat-treatment. It is result from exsistant of ${\delta}^{\prime}$-precursor phase. The effect acceleration in a binary alloy was not appeared and the over-aging ternary alloy was accelerated with increase of the reduction rate. It is caused by combination effect of ${\delta}^{\prime}$ and composite phase.

• Journal of Pharmacopuncture
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• v.20 no.3
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• pp.227-229
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• 2017

Fibrosis of skeletal muscle following acupuncture is an iatrogenic disorder. The present case illustrates a patient with a unilateral fibrotic formation on a thumb muscle after acupuncture injection therapy with red sage. The patient in the present case was a counter-terrorism police officer with right-handedness; he noted a palpable nodule three months after injection therapy at his left first dorsal interosseous in which the acupuncture point LI4 (He Gu) is located. He also found a reduction in the strength of his left pinch grip that noticeably affected his left handgun marksmanship. However, being ambidextrous in single-hand pistol shooting is an essential requirement for counter-terrorism police officers. Based on the patient's medical history and claims, no underlying disease or trauma was found to be associated with his current complaint. During physical examination, a fibrotic formation in his left first dorsal interosseous muscle was visualized by using diagnostic ultrasound; also, as confirmed with dynamometry, the strength of his left pinch grip was significantly lower than that of the right counterpart. Because acupuncture injection therapy has three components, antiseptic practices, the mechanical action of syringe insertion, and the pharmacological effect of the sterile herb extract, any one of the components may have contributed to the present adverse event. The first dorsal interosseous muscle is small in dimension and rather vascular; thus, it is not an ideal site for intramuscular injection. When a clinician needs to treat a patient by performing acupuncture at the LI4 acupoint and injecting a herbal extract simultaneously, the clinician should only mechanically stimulate the LI4 acupoint while injecting the herbal medicine into the LI14 (Bi Noe) acupoint on the same meridian, the LI14 acupoint being located in the distal portion of the deltoid muscle and being fairly close to the universally agreed upon site on the upper arm for safe administration of an injection.

• Toxicological Research
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• v.25 no.1
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• pp.17-21
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• 2009

The effects of aqueous extract of Schizandra Chinensis Fruit (AESC) on cadmium-induced changes of monoamine neurotransmitters in the different brain regions of adult rats were investigated. Male rats were received intraperitoneal (i.p.) administration of CdCl2 (0.6 mg/kg/d) for 21 days and sacrificed 7 days after the last administration. Concentrations of norepinephrine (NE), dopamine (DA) in striatum and serotonin (5-HT), 5-hydroxyindole acetic acid (5-HIAA) in cortex were measured by HPLC. There were significant decreases of NE, DA, 5-HT and 5-HIAA in Cd intoxicated rats (P < 0.05), while pretreatment with AESC (20 mg/kg/d or 60 mg/kg/d, p.o., 30 min before $CdCl_2$) greatly inhibited the decrease of monoamine transmitters, respectively (P < 0.05). Also, AESC significantly increased the reduction of glutathione contents and superoxide dismutase activities in cortex induced by $CdCl_2$. These results suggest that AESC ameliorates Cd-induced depletion of monoamine neurotransmitters in brain through its antioxidant activity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1453-1461
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• 2022

The accuracy of peripheral object recognition algorithms using 3D data sensors such as LiDAR in autonomous vehicles has been increasing through many studies, but this requires high performance hardware and complex structures. This object recognition algorithm acts as a large load on the main processor of an autonomous vehicle that requires performing and managing many processors while driving. To reduce this load and simultaneously exploit the advantages of 3D sensor data, we propose 2D data-based recognition using the ROI generated by extracting physical properties from 3D sensor data. In the environment where the brightness value was reduced by 50% in the basic image, it showed 5.3% higher accuracy and 28.57% lower performance time than the existing 2D-based model. Instead of having a 2.46 percent lower accuracy than the 3D-based model in the base image, it has a 6.25 percent reduction in performance time.

• Journal of the Korean Ceramic Society
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• v.34 no.3
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• pp.225-232
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• 1997

The performance characteristics of high rate discharge LiSOCl2 cells are highly affected by carbon cathode. During the cell discharge, SOCl2 reduction takes place at the porous carbon cathode, resulting in the precipitation of reaction products, mainly LiCl, within the pores of the substrate. This leads to eventual passivation of the cathode surface and resulting cell failure. To improve the cathode performance, we ex-amined discharge reactions of cathodes (half-cell, 50 mA/$\textrm{cm}^2$ constant current) with various surface density and thickness. The carbon cathode with the optimum capacity for our application is surface density 0.04 g/$\textrm{cm}^2$ and thickness 1.4mm carbon. The carbon cathode with surface density 0.04g/$\textrm{cm}^2$ and thickness 1.4 mm exhibits decreased polarization, increased discharge duration time and capacity (Ah/$\textrm{cm}^2$) as compared with that with surface density 0.04g/$\textrm{cm}^2$ and thickness 0.8mm. The porosities analyses on the two carbon cathodes show that total pore volume of the carbon cathode with thickness 1.4 mm is larger than that with thickness 0.8mm. The increased volume of mesopores (0.05$\mu$m~0.5$\mu$m) and macropores(>0.5$\mu$m) is ob-served with the carbon cathode with thickness 1.4mm as compared with that with thickness 0.8mm, which can be related with the observed capacity increase. We observed LiCl crystals, cubic crystallites and fused, plate-like aggregates, and some elemental S as discharge products by EDS and XRD.

• Korean Journal of Materials Research
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• v.2 no.6
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• pp.389-397
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• 1992

Workability and aging behavior of Mg-Li-Al alloys hate been investigated with variation of Li and Al contents. It was found that ${\alpha}$(HCP) + ${\beta}$(BCC) two phase structure reveals better workability than ${\alpha}$(HCP) single phase structure. Increase of workability is attributed to the additional slip on pyramidal and prism planes besides the slip on basal plane of HCP Mg. Workability of ${\alpha}$+${\beta}$ two phase structure is improved with increased amount of Al. Among alloys studied in the present study, reduction limit up to 62 % was obtained for Mg-8.08Li-4.26Al. MgL$i_2$Al(${\theta}$) aging precipitation was observed in ${\alpha}$+ ${\beta}$ two phase structure, while it was not in a single phase structure. Result of microhardness reveals peak hardness for ${\alpha}$ +${\beta}$ two phase structure due to $\theta$ precipitate in ${\theta}$ phase. In ${\alpha}$+${\beta}$ two phase Mg-Li-Al alloys, hardness increased with increasing amount of Al. It is believed that addition of Al raised the amount Al partition in u phase and ${\theta}$ precipitation in ${\beta}$ phase.

• ETRI Journal
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• v.27 no.3
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• pp.312-318
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• 2005

Mid-span spectral inversion (MSSI) has to utilize high optical pump power, for its operation principle is based on a nonlinear optical wavelength conversion. In this paper, a low pump-power operation of MSSI-based chromatic dispersion compensation (CDC) has been achieved successfully, for the first time to our knowledge, by introducing a noise pre-reduction scheme in cascaded wavelength conversions with periodically poled $LiNbO_3$ waveguides at a relatively low operation temperature. As preliminary studies, phase-matching properties and operation-temperature dependence of the wavelength converter (WC) were characterized. The WC pumped at 1549 nm exhibited a wide conversion bandwidth of 59 nm covering the entire C-band and a conversion efficiency of -23.6 dB at 11 dBm pump power. CDC experiments were implemented with 2.5 and 10 Gb/s transmission systems over 100 km single-mode fiber. Although it is well-known that the signal distortion due to chromatic dispersion is not critical at a 2.5 Gb/s transmission, the clear recovery of eye patterns was identified. At 10 Gb/s transmission experiments, eye patterns were retrieved distinctly from seriously distorted ones, and notable improvements in bit-error rates were acquired at a low pump power of 14 dBm.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3499-3502
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• 2013

MicroRNAs (miRNAs) are a class of endogenously expressed small, non-coding, single-stranded RNAs that negatively regulate gene expression, mainly by binding to 3'- untranslated regions (3'UTR) of their target messenger RNAs (mRNAs), which cause blocks of translation and/or mRNA cleavage. Recently, miRNAprofiling studies demonstrated the microRNA-497 (miR-497) level to be down-regulated in all prostate carcinomas compared with BPH samples. The purpose of this study was to investigate the potential role of miR-497 in human prostate cancer. Proliferation, cell cycle and apoptosis assays were conducted to explore the potential function of miR-497 in human prostate cancer cells. Results showed that miR-497 suppressed cellular growth and initiated G0/G1 phase arrest of LNCaP and PC-3 cells. We also observed that miR-497 increased the percentage of apoptotic cells by increasing caspase-3/7 activity. Taken together, our results demonstrated that miR-497 can inhibit growth and induce apoptosis by caspase-3 activation in prostate cancer cells, which suggest its use as a potential therapeutic target in the future.

• Journal of the Korean Ceramic Society
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• v.48 no.4
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• pp.269-277
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• 2011

Glass-ceramics based on lithium disilicate($Li_2Si_2O_5$) are prepared by heat-treatment of glasses in a system of $SiO_2-Li_2O-K_2O-Al_2O_3$ with different compositions. The crystallization heat-treatment was conducted at the temperature range of $700{\sim}900^{\circ}C$ and samples were analyzed by XRD and SEM. Mechanical properties were determined by a Vicker's hardness and 4 point bending strength. When $SiO_2/Li_2O$ ratio increased, cristobalite and tridymite crystals showed more predominate than lithium disilicate crystals. Increase in $Al_2O_3$ contents in the glass suppressed crystallzation of lithium disilicate crystals. Increase in ZnO, $B_2O_3$ contents in the glass decreased crystallization temperature of lithium disilicate crystals, and increased mechanical properties because of the reduction of the lithium disilicate crystal size.