• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.677-687
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• 1996

This study was conducted to evaluate the tissue responses histologically to three root canal cements : Sealapex, AH-26, and zinc oxide-eugenol cement. Twelve white female Sprague-Dawley rats, weighing between 350 and 400 gm, were anesthetized with an intraperitoneal injection of Ketamine hydrochloride(0.4 ml). After shaving the sites selected(left and right scapular areas, left and right pelvic areas), the animal's backs were scrubed with soap and water, and sterilized with absolute alcohol. Each material was mixed to a thin consistency to flow out easily through a 24-guage needle, and loaded into a sterile, disposable plastic 1-ml syringe. All of the rats were injected subcutaneously with 0.1 ml of the three test sealers. Normal saline was used as a control. Animals were sacrificed after 48hr, 1, 4, and 12 weeks by overanesthetization using jars containing anesthetic ether. The tested sites were surgically removed with the surrounding tissue and fixed with 10% formalin. After 48 hours specimens were embedded in paraffin, sectioned to an average thickness of $6{\mu}m$ thick, stained with hematoxylin-eosin. The slides were examined under the light microscope. The results were obtained as follows 1. All material except the control showed various degree of inflammation on 48 hr. 2. Sealapex : In early stage, severe inflammatory cell infiltration was observed. At the 4th weeks observation, graunlomatous tissue with macrophage and foreing body giant cells containing many dark particles in their cytoplasm was observed. 3. AH-26 : Mild inflammatoy reaction was observed with AH-26 throughout the experimental period. 4. Zinc oxide-eugenol cement : Severe inflammatory cell infiltration, necrosis along the material, edema could be seen in early stage. Zinc oxide-eugenol cement maintained a moderate/severe reaction throughout the experimental period.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.99-104
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• 2024

In this study, a carbon coated hollow silicon (HSi/C) composite material was prepared for anode material of high-capacity lithiun-ion battery. Hollow silica (HSiO₂) was synthesized by the Stöber method with CTAB (N-Cetyltrimethylammonium bromide). The HSi/C anode composite was manufactured by carbon coating after magnesiothermic reduction of HSiO₂. The physical and electrochemical characteristics of the prepared anode materials were investigated based on CTAB amount. In the FE-SEM analysis, it was found that the HSiO₂ particle size increased as CTAB amount decreased, but shell thickness decreased. The HSi/C composites exhibited high initial discharge capacities of 1866.7, 2164.5 and 2188.6 mAh/g with various CTAB ratios (0.5, 1.0, 1.5), respectively. After 100 cycles of charge-discharge, 0.5-HSi/C demonstrated a high reversible capacity of 1171.3 mAh/g and a capacity retention of 70.9%. Electrochemical impedance spectroscopy (EIS) was employed to analyze the impedance characteristics, and it revealed that 0.5-HSi/C showed more stable resistance characteristics than HSi/C composites with other CTAB amount over 20 cycles.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.140-147
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• 2024

In order to increase the utilization of biomass, an electrochemical performance was considered after manufacturing a carbon anode material (SV-C) for a Setaria viridis-based lithium ion secondary battery through a heat treatment process. When the heat treatment temperature of the Setaria viridis is as low as 750 ℃, the capacitance (1003.3 mAh/g, at 0.1 C) is high due to the negative (-) charge of oxygen present on the surface attracting lithium, along with the low crystallinity and high specific surface area (126 m²/g), but the capacity retention rate is believed to be as low as 61.0% (at 500 cycles and 1 C). In addition, it was confirmed that when the heat treatment temperature increased to 1150 ℃, the carbon layer was condensed to be excellent in arrangement, and the structural defects were reduced, resulting in a significant reduction in the specific surface area (32 m²/g) of the pores. Furthermore, when the surface defects of the anode material are reduced and the crystallinity is increased, the capacity retention rate is as high as 89.7% (at 500 cycles and 1 C), but the degree of defects is small, the active point is reduced, and the specific capacity is considered to be very low at 471.7 mAh/g. In the scope of this study, it was found that in the case of the Setaria viridis-based carbon anode material manufactured according to the heat treatment temperature, the surface oxygen content and crystallinity have higher reliability on the electrochemical properties of the anode material than the specific surface area.

• Journal of the Korean Electrochemical Society
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• v.11 no.3
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• pp.154-158
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• 2008

The synthesis of hollow ${Sb_93}{Pt_7}$ nanospheres smaller than 30 nm with a shell consisting of smaller nanoparticles, with an average particle size of ${\sim}$ 3 nm is reported. The formation of this alloy is driven by galvanic replacement reaction involving Sb nanoparticles and ${H_2}{PtCl_6} $ without need for any additional reductants. Further, the reaction proceeds selectively as long as the redox potential between two metals is favorable. The capacities of the hollow samples are 669 and 587mAh/g at rates of 1 and 7C, respectively, while those values for the nanoparticles are 647 and 480mAh/g at rates of 1, 7C, respectively. This result shows the significantly improved capacity retention of the hollow sample at higher C rates, indicating that high surface area of the hollow nanospheres makes the current density more effective than that for the solid counterpart.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.123-125
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• 2004

The importance for Internet security has being increased and the Internet Protocol Security (IPSec) standard, which incorporates cryptographic algorithms, has been developed as one solution to this problem. IPSec provides security services in IP-Layer using IP Authentication Header (AH) and IP Encapsulation Security Payload (ESP). In this paper, we propose IPSec cryptographic processor design based AMBA architecture. Our design which is comprised Rijndael cryptographic algorithm and HAMC-SHA-1 authentication algorithm supports the cryptographic requirements of IP AH, IP ESP, and any combination of these two protocols. Also, our IPSec cryptographic processor operates as AMBA AHB Slave. We designed IPSec cryptographic processor using Xilinx ISE 5.2i and VHDL, and implemented our design using Xilinx's FPGA Vertex XCV600E.

• Journal of Electrochemical Science and Technology
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• v.3 no.4
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• pp.172-177
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• 2012

Mo-doped $LiFePO_4$ was synthesized via co-precipitation method using sucrose as the carbon source. Structure, surface morphology, and the electrochemical properties of the synthesized olivine compounds were investigated using Rietveld refinement of X-ray diffraction data (XRD), scanning electron microscopy (SEM), and electrochemical charge-ischarge tests. Spherical morphology with the particle size of ${\sim}8{\mu}m$ authenticated the enhanced tap density and volumetric energy density of the synthesized materials. Charge-discharge behavior of $LiFePO_4$ and Mo-doped $LiFePO_4$ cells demonstrated a specific capacity of 130 and 145 mAh $g^{-1}$, respectively. Mo-doped $LiFePO_4$ cells exhibited an excellent discharge capacity at 96 mAh $g^{-1}$ at 7 C-rate.

• Bulletin of the Korean Mathematical Society
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• v.47 no.1
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• pp.167-178
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• 2010

We discuss the critical points of the functional $F_{\lambda,\mu}(J,g)=\int_M(\lambda\tau+\mu\tau^*)d\upsilon_g$ on the spaces of all almost Hermitian structures AH(M) with $(\lambda,\mu){\in}R^2-(0,0)$, where $\tau$ and $\tau^*$ being the scalar curvature and the *-scalar curvature of (J, g), respectively. We shall give several characterizations of Kahler structure for some special classes of almost Hermitian manifolds, in terms of the critical points of the functionals $F_{\lambda,\mu}(J,g)$ on AH(M). Further, we provide the almost Hermitian analogy of the Hilbert's result.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.1
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• pp.123-128
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• 1996

저온저장 중 품질 열화가 일어난 단감의 산업적 이용성을 증진하기 위한 감식초의 가공조건을 조사한 결과, 연화된 단감을 폐쇄하여 종초 10%와 알코올 4%를 첨가한 후 발효온도 3$0^{\circ}C$에서 2주 이내에 산도 4%이 상인 감식초가 발효되었으며, 15$^{\circ}C$에서 3주간의 숙성 조건에서 식초 고유의 향미가 형성된 반면 포도당과 초산의 첨가는 최종 제춤의 품질을 저하시키는 결과를 얻었다. 연화된 단감의 열처리 효과는 잡균에 의한 오염 가능성을 제거시킬수 있었기 때문에 품질의 안정화를 위한 필수적인 공정으로 볼 수 있었다. 종초에서 분리된 산생성 균주의 생육과 산생성능을 조사한 결과, AH-1은 발효초기에 증식한 반면 AH-2는 발효 푸기에 증식하면서 산을 생성하였다. 따라서 이런 균주들이 서로 어우러져 최종적인 감식초의 품질을 결정하는 것으로 사료되었다. 감식초의 유기산 성분은 대부분이 acetic acid로 구성되어 있었고, 그 다음은 $\beta$-galac-turonic acid였다. 그리고 tanin 함량은 시판제품에 비하여 16~44mg% 정도 적게 나타났다.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.186-186
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• 2001

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental toxin that activates the aryl hydrocarbon receptor (AhR) and disrupts multiple endocrine signaling pathways by enhancing ligand metabolism, altering hormone synthesis, down regulating receptor levels, and interfering with gene transcription. And TCDD-mediated gene transactivation via the AhR has been shown to be dependent upon estrogen receptor (ER) expression in human breast cancer cells.(omitted)

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.4
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• pp.48-54
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• 2009

We implemented the Aural Cueing System(ACS) system of the reconfigurable tactical trainer(RTT) for th rotor aircraft. RTT provides a collective training system to meet aviation training requirements and supports organizational training for aviations units in combined arms collective training and mission rehearsal. ACS handles the volume, pitch and repetition of the digitally stored sounds based on commands it receives from an UDP/IP. In this paper, we explained and implemented the conceptual and detail design the ACS system for the rotor aircraft such as AH-1H(Iroquios), UH-60(Blackhwak), AH-1(Cobra) etc. The conceptual design composed of the sound cueing data analysis, sound modelling which is inner, outer, weapon and warn environment of rotor aircraft, sound synthesis and replay.