• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.169-169
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• 2008

To keep pace with scaling trends of CMOS technologies, high-k metal oxides are to be introduced. Due to their high permittivity, high-k materials can achieve the required capacitance with stacks of higher physical thickness to reduce the leakage current through the scaled gate oxide, which make it become much more promising materials to instead of $SiO_2$. As further studying on high-k, an understanding of the relation between the etch characteristics of high-k dielectric materials and plasma properties is required for the low damaged removal process to match standard processing procedure. There are some reports on the dry etching of different high-k materials in ICP and ECR plasma with various plasma parameters, such as different gas combinations ($Cl_2$, $Cl_2/BCl_3$, $Cl_2$/Ar, $SF_6$/Ar, and $CH_4/H_2$/Ar etc). Understanding of the complex behavior of particles at surfaces requires detailed knowledge of both macroscopic and microscopic processes that take place; also certain processes depend critically on temperature and gas pressure. The choice of $BCl_3$ as the chemically active gas results from the fact that it is widely used for the etching o the materials covered by the native oxides due to the effective extraction of oxygen in the form of $BCl_xO_y$ compounds. In this study, the surface reactions and the etch rate of $Al_2O_3$ films in $BCl_3/Cl_2$/Ar plasma were investigated in an inductively coupled plasma(ICP) reactor in terms of the gas mixing ratio, RF power, DC bias and chamber pressure. The variations of relative volume densities for the particles were measured with optical emission spectroscopy (OES). The surface imagination was measured by AFM and SEM. The chemical states of film was investigated using X-ray photoelectron spectroscopy (XPS), which confirmed the existence of nonvolatile etch byproducts.

• Korean Journal of Plant Resources
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• v.30 no.4
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• pp.435-449
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• 2017

A floristic study on the vascular plants from Mt. Seounsan region, which ranges from Seoun-myeon, Anseong-si, Gyeonggi-do to Baekgok-myeon, Jincheon-gun, Chungcheongbuk-do, was conducted 9 times in total, from April 2014 to October 2015. Based on the voucher specimens, it was revealed that the vascular plants in this region comprised 501 taxa: 97 families, 306 genera, 439 species, 5 subspecies, 51 varieties, and 6 forma. Among these plants, 185 taxa were recorded for the first time from this region. 8 Korean endemic species including Asarum patens (K.Yamaki) B.U.Oh, Scutellaria insignis Nakai, and Weigela subsessilis (Nakai) L.H.Bailey were found in this region. 5 taxa of rare plants designated by the Korea Forest Service, including Iris ruthenica KerGawl., Leontopodium leontopodioides (Willd.) Beauverd, and Tricyrtis macropoda Miq., were also found. 11 taxa of floristic regional indicator plants in the $3^{rd}$ to the $5^{th}$ degrees were identified. In addition, 46 taxa of naturalized plants were recorded, and 2 taxa of ecosystem disturbance plants, which were Ambrosia trifida L. and Aster pilosus Willd., also found.

• The Korea Journal of Herbology
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• v.30 no.6
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• pp.7-15
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• 2015

Objectives : Rosa laevigata Michx. has been used for the treatment of renal disease in traditional Korean medicine. In this study, we investigated cytoprotective effect of R. laevigata water extract (RLE) against oxidative stress induced by arachidonic acid (AA) + iron.Methods : To evaluate the protective effects of RLE against AA + iron-induced oxidative stress in HepG2 cell, cell viability and changes on apoptosis-related proteins were assessed by MTT and immunoblot analyses. The effects of RLE on reduced glutathione level, production of reactive oxygen species and mitochondrial membrane potential were also monitored. Furthermore, to verify underlying molecular mechanism, NF-E2-related factor 2 (Nrf2) was examined by immunoblot analysis. Additionally, Nrf2 transactivation and its downstream target genes expression were also determined by reporter gene and realtime RT-PCR analyses.Results : RLE pretreatment (30-300 μg/ml) prevented cells from AA + iron-mediated cell death in a concentration dependent manner. In addition, 100 μg/ml RLE inhibited AA + iron-induced glutathione depletion, reactive oxygen species production and mitochondrial dysfunction. RLE accumulated nuclear Nrf2 and also transactivated Nrf2, which was evidenced by antioxidant response element- and glutathione S-transferase A2-driven luciferase activities and mRNA level of glutamate-cysteine ligase catalytic subunit, NAD(P)H:quinone oxidoreductase 1 and sestrin 2. Moreover, protective effect of RLE against AA + iron was abolished in Nrf2 knockout cells.Conclusions : These results indicate that RLE has the ability to protect hepatocyte against oxidative stress through Nrf2 activation.

• Proceedings of the Korean Reliability Society Conference
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• 2006.05a
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• pp.239-246
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• 2006

프레스다이용 코일스프링은 자동차 및 전자제품의 외형생산에 필요한 금형 내에 장착되는 금형용 스프링으로서 녹아웃 및 스트리퍼 등에 사용되고 있다. 프레스다이용 코일스프링이 사용 중 파손 시에는 고가인 금형의 손상 및 생산성에 영향을 미칠 수도 있기 때문에 사용 환경에서의 신뢰성확보가 요구되어지고 있다. 특히 중(重)하중 및 극중(極重)하중용 스프링은 과거 현장에서 파손사례가 자주 발생함으로 인해 외산을 선호하는 경향이 있는 형편이다. 이에 국산 스프링의 신뢰성검증 및 확보를 위해 신뢰성기반구축사업을 통해 신뢰성평가기준(RS D 0014)가 제정되었으며, 이 평가기준에 의거하여 국내 업체의 제품에 대해 신뢰성평가를 실시하였다. 프레스다이용 코일스프링의 파손원인은 주로 반복하중에 의한 피로파손과 일정한 변위의 변형으로 발생하는 코일스프링 자유높이의 축소로 크게 구분되어질 수 있다. 시험결과 주 파손양상은 피로에 의한 균열발생이었으며, 코일 끝단부와 끝단부 직하부의 코일과의 마찰에 의한 균열발생이 주원인이었다. 즉, 코일의 끝단면과 직하면 코일이 연속적으로 부딪침으로써 발생한 변형 및 마모에 의해 표면균열이 발생하고, 표면균열에서 반복적인 부하하중이 가해짐으로써 피로균열 진전을 통해 점차적으로 파손이 진행되어졌음을 알 수 있었다. 본 발표에서는 기준에 의거하여 로하중용 프레스 다이용 코일스프링을 평가한 신뢰성평가시험 결과에 대해 보고하고, 파단면 관찰과 외산제품과의 미세조직 및 조성 등의 비교분석결과 등을 기초로 파손원인을 분석한 결과에 대해 보고하고자 한다.제고할 수 있을 것으로 기대한다.X>$CdCl^+,\;CdSO_4$ 등이 형성되었다. 수은의 경우는 해수 및 증류수를 용출용매로 이용한 모든 경우에서 납, 구리, 카드뮴과는 달리 대부분 침전하였다. 더욱이 해수에 존재하는 고농도 염소($Cl^-$)와의 수착으로 인해 finite solid인 calomel($Hg_2Cl_2$)이 형성되어 대부분 침전(SI=0)되기 때문에 납, 구리, 카드뮴 보다 더 낮은 환경이동성을 갖을 것으로 사료된다. 상기 실험결과 용출용매로 증류수와 해수를 이용했을 때, 제강 슬래그에서 용출되는 납, 구리, 카드뮴, 수은의 용출 경향의 차이를 확인할 수 있었고 이에 따라서, 납, 구리, 카드뮴의 용출 유해성은 낮기 때문에 해양구조물로의 제강슬래그 유효이용은 적합할 것으로 판단되었다.im80%$로 계산되었다. 열형광선량계로 측정된 방사선량은 각각 1.8, 1.2, 0.8, 1.2, 0.8 (70 cm 거리) cGy로 측정되었으며, 환자의 복부 표면에서의 서베이메터를 이용한 측정량은 10.9 mR/h였다. 차폐구조물의 사용 시 전체 치료 동안에 태아선량은 약 1 cGy 정도로 평가되었다. 결론 : AAPM Report No.50의 자료에 따르면, 임산부의 방사선 치료 시 태아의 방사선 피폭선량은 5 cGy 이하일 경우에 방사선 피폭에 따른 태아의 위험이 거의 없는 것으로 제시되고 있다. 본원에서 차폐 구조물을 설치하였을 경우에 측정된 태아선량은 약 1 cGy로 측정되었고, 고안된 차폐구조물

• Korean Journal of Plant Resources
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• v.15 no.3
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• pp.269-278
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• 2002

To establish the mass propagation methods of Weigela subsessilis,, a promising native plant species for horticultural use, several factors influencing rooting from stem cuttings were evaluated. Softwood cuttings showed best rooting rate, 70~77%, in all the cutting media tested, 2.8 times more than hardwood cuttings in which perlite was best medium. The rooting from hardwood cuttings was promoted by higher concentration of all growth regulators used,500 mg.L$^{-1}$ NAA being the best with 80%. More than 80% of softwood cuttings treated by growth regulators produced roots, especially 100, 500, and 1000mg.L$^{-1}$ NAA producing 97％. Roofings from semi-wood cuttings was enhanced by all the growth regulators, except 1000 mg.L$^{-1}$ concentration in which rooting was reduce. Higher rooting rate was obtained by higher concentration and longer soaking duration of NAA in case of hardwood cutting. Softwood cutting showed 100 ％ rooting by soaking treatment with 500 mg.L$^{-1}$ NAA for 3 min. Rooting rate of semi-hardwood cuttings was promoted by higher concentration and longer soaking with growth regulators, However, the degree of improvement was lower than soft and hardwood cutting.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.199-205
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• 2005

Physicochemical quality characteristics of seed mashes were investigated for development of new creative breadmaking in bakery. Aridity of seed mashes fermented with Koji, lactic acid bacteria, and baker's yeast was slightly lower than those fermented with Koji and yeast. ${\alpha}-Amylase$, saccharifying amylase, and acidic protease activities of seed mash composed of water (560 mL) and Koji (400 g) were 0.26 SKB, 36 SP, and 645 HUT/g, respectively. Reducing sugar content of seed mash made with Koji increased up to 13.04% after 36 hr fermentation, then decreased drastically thereafter, whereas that of seed mashes made with Koji, yeast, and lactic acid bacteria increased up to 6.5% at 6 hr, decreased to 1 to 2.5% at 12 hr, and remained less than 0.7% after 18 hr fermentation. Total organic acid contents were 10.4-12.25mg/mL. Flavor compounds including ethyl acetate, ethyl caprylate, isoamyl acetate, and p-vinyl guaiacol were detected in seed mash fermented with Koji, yeast, and L. brevis. These results show use of seed mash fermented with Koji, S. cerevisiae, and lactic acid bacteria enhances bread flavor.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.709-714
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• 2002

Fish sauce is a traditional Korean fermented seafood and has been used as a condiment since long time ago. Northern sand lance sauce was manufactured with koji, enzyme, and squid viscera of fermentation accelerating agents, and ripened at $15^{\circ}C$. Moisture contents of all samples decreased gradually as fermentation progressed. Crude protein contents increased rapidly up to 1 month-fermentation and then increased slightly up to 5 month. Northern sand lance sauce with squid viscera was the highest in the contents of protein and lipid. The ash content increased gradually during the fermentation periods, while pHs decreased. TMA contents increased up to 3 month-ripening and then decreased slightly. Amino nitrogen content of Northern sand lance sauce with squid viscera increased as fermentation progressed and was the highest among all samples. VBN contents increased up to 5 month-ripening and that of Northern sand lance sauce with squid viscera was the higher than others.

• Polymer(Korea)
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• v.29 no.5
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• pp.501-507
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• 2005

Small intestinal submucosa (SIS) had been widely used as a biomaterial without immune rejection responses. SIS sponges prepared by crosslinking with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). SIS powders dissolved in $3\%(v/v)$ acetic acid aqueous solution for 48hrs and freeze-dried. EDC solution ($H_2O$ : ethanol = 5 : 95) as a crosslink agent was used in concentration of 100mM. In vitro, rat-BMSCs seeded in SIS sponges and induced the osteogenesis for 28 days. We have characterized the osteogenic potential of rat-BMSCs in SIS sponges by alkaline phosphatase activity(ALP), n assay, SEM and RT-PCR for osteogenic phenotype. In SEM, all morphology of SIS sponges was regular and showed interconnected pore structure. By RT-PCR analysis, we observed type I collagen expression. These results demonstrate osteogenic differentiation of rat-BMSCs. In conclusion, we confirmed that the morphology of surface, cross-section, and side of SIS sponges were highly porous with good interconnections between each pores, which can support the surface of cell growth, proliferation, and differentiation. This result indicates that SIS sponge is useful for osteogenesis of BMSCs.

• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.29-34
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• 1970

This experiment was conducted to investigate the influence of amounts of lime dressed on the growth of rice by the treatment of percolation and nonpercolation in the acid sulphate soil. And also analysis of soil chemical components after treatment was carried out. The results obtained were summarized as follows: 1. In the initial stage of growth, number of tillers and plant length showed no distinct differences between the treatments of percolation and nonpercolation, but after August the effect of lime appeared and the percolation treatment was more effective than the nonpercolation. 2. Lime dressing affected good influence on the panicles, grain per panicles and the rate of grain formation, and the treatment of percolation showed better results than nonpercolation. 3. If the yield of rough rice in the control (nonpercolation and lime dressing) was 100, it was 194 in the treatment of nonpercolation 12me/100gr of lime dressed, 268 in the treatment of percolation-4me/100gr of lime and 315 in the 8me/100gr-percolation. 4. Lime dressing affected good influence on the control of Helminthosporium leaf spots. 5. In the case of lime dressing, amounts of available phosphate and soluble silicon dioxide were increased, but ferrous ion ($Fe^{{+}{+}}$) were decreased.

• Journal of the Korean Vacuum Society
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• v.20 no.6
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• pp.436-441
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• 2011

Metal coating with several nanometer thickness was applied on the carbon nanotubes (CNTs) in order to improve electron emission characteristics and emission reliability for the potential applications in the area of various electron sources and displays. CNTs were grown on the 2-nm thick Invar (52% Fe, 42% Ni, 6% Co alloy)-catalized Si substrate by using plasma-enhanced chemical vapor deposition at $450^{\circ}C$. In order to reduce the spatial density of densely packed CNTs, as-grown CNTs were partly etched back by $N_2$ plasma and subsequently coated with 5~150 nm thick Ti by a sputtering method. 5 nm thick Ti-coated CNTs produced four times higher emission current density at the electric field of 6 V/${\mu}m$ and much lower emission current fluctuation, compared with the as-grown CNTs. These improved emission properties are mainly due to not only the work function of Ti (4.3 eV) lower than that of pristine CNTs (5 eV), but also lower contact resistance and better adhesion between CNT emitters and substrate accomplished by Ti coating.