슬래그중 고체철의 산화거동에 관한 속도론적 고찰

백종문,이홍기,고정호,민동준 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.12

The kinetic experiments have been made on iron oxidation in slag by oxidizing gases at 1387∼1500℃. The effect of temperature, FeO content and oxygen potential of gas on the reaction rate have been examined. The iron oxidizing rate is considerably increased with increasing temperature and FeO content in slag. It was also found that the rate controlling step of reaction have been depended on the temperature, FeO content in slag and (P_(co₂)/P_(co) as an oxygen potential at gas/slag interface. The dependence of the overall reaction rate constant on temperature and initial FeO content in slag at 1450℃ could be expressed as follows; log k_(overall) = -0.36-10,820/T[㏖/㎠·sec·atm] k_(overall) = 1.04×10^(-7)(wt%FeO)^(0.75)[㏖/㎠·sec·atm] In condition of high oxygen potential such as high FeO content and (P_(co₂)/P_(co)), the chemical reaction at interface between slag and gas might play a important role as a rate controlling step of overall reaction, which is controlled by the dissociation of CO₂ at slag/gas interface. But in case of low (P_(co₂)/P_(co)), mass transfer and chemical reaction at interface between slag and iron become important as a rate controlling step. The reaction mechanism of iron oxidization in slag by gas have been discussed in terms of rate constant for elementary reactions.

LPG 탱크로리 수송중 위험성 평가에 관한 연구

이재준,김윤화,엄성인,고재욱,백종배,윤성렬 한국산업안전학회 1997 한국안전학회지 Vol.12 No.4

Demand of LPG and LNG will increase continuously due to high calories, clearness, and convenience for usage. These gases are used widely for power plants, industrial plants, and domestic fuel. But accidents related with gas are increasing in proportion to increment of gas usage. Especially, LPG has high ignitability due to weak dispersion to air and accumulation at low place because LPG is heavier than air. There are many hazards during transportation as well as production, storage, and usage of LPG. Commonly, tank lorry is used for inland transportation of LPG. If tank lorry were to raise leakage incidents and then LPG released during transporting, the accidents cause serious effects on the environment as well as human damage of surrounding area. In this study, therefore, hazards which cause LPG of tank lorry to leak during transportation were identified and risk of LPG transportation was assessed quantitatively. Also, the result of this study might be a useful measure for predicting damage and preparing safe transportation strategies of LPG tank lorry.

독성물질 사용 저장시설에 대한 개인적 위험성 산정에 관한 연구

김성빈,김윤화,이철,엄성인,고재욱,백종배 한국산업안전학회 1997 한국안전학회지 Vol.12 No.1

These days leakage incidents of toxic materials cause serious effects on the nearby residents as well as the workers around the accidents accompanying massive material losses and human damages through widening influencial areas. The risk measure through adequate quantitative analysis as well as the qualitative analysis of the leakage incidents of toxic materials becomes an urgent issue. The damage, of the leakage incident on the surrounding area of the dangerous toxic material facilities was calculated quantitatively by adopting several models in this research. First, the calculations of the leakage velocity from the factories were performed by using source model for the assessment of the influential area, and the damages on the nearly residents were calculated by using the dispersion model and the effect model. The probability of the incidents was computed based on $quot;The manual for classification and priorization of major incidents$quot; published by IAEA(International Atomic Energy Agency). Above calculated damage area and incident probability were further adopted in this study to induce the individual and societal risk, quantitatively. The calculated data of the real incident of the toxic material leakage showed reasonable agreements to the actual damage of the incidents, which showed a validity of this study. The result of this study might be a helpful measure for predicting damages and preparing safety systems for similar kinds of incidents.

최근의 금형 표면기술 현황

김성완,이구현,남기석,권식철,백운승 한국열처리공학회 2000 熱處理工學會誌 Vol.13 No.2

무수 불화수소와 메탄올의 기상식각에 의한 실리콘 표면 미세 가공

장원익,최창억,이창승,홍윤식,이종현,백종태,김보우 한국센서학회 1998 센서학회지 Vol.7 No.1

In silicon surface micro-machining, the newly developed GPE(gas-phase etching) process was verified as a very effective method for the release of highly compliant micro-structures. The developed GPE system with anhydrous HF gas and CH₃OH vapor was characterized and the selective etching properties of sacrificial layers to release silicon micro-structures were discussed. P-doped polysilicon and SOI(silicon on insulator) substrate were used as a structural layer and TEOS(tetraethyorthosilicate) oxide, thermal oxide and LTO(low temperature oxide) as a sacrificial layer. Compared with conventional wet-release, we successfully fabricated micro-structures with virtually no process-induced suction and residual product.

Cu-Al-Ni-Ti-Mn 합금의 변태특성 및 기계적 성질에 미치는 가공열처리의 영향

강조원,장우양,양권승,이영수,곽사호,김춘동,백승남 한국열처리공학회 1999 熱處理工學會誌 Vol.12 No.2

The distribution of the second phase, the change of transformation temperature and mechanical properties with thermomechanical treatment conditions were investigated by metallography, calorimetry, EDS, tensile test and fractography in a Cu-Al-Ni-Ti-Mn alloy. The cast structure revealed Ti-rich precipitates(X_L phase) between dendrite arms, which have been identified as (Cu,Ni)₂TiAl intermetallic compounds. By homogenizing above 900℃, the X_L phase was melted in the matrix, while the X_s phase was precipitated in matrix and the volume fraction of it was increased. When hot-rolled specimen was betatized below 750℃, recrystallization could not be observed. However, the specimen betatized above 800℃ was recrystallized and the grain size was about 50㎛, while X_s phase was precipitated in matrix. With raising betatizing temperature, M_s and A_s temperatures were fallen and transformation hysteresis became larger. The strain of the specimen betatized at 800℃ was 8.2% as maximum value. The maximum shape recovery rate could be obtained in the specimen betatized at 800℃ but it was decreased due to the presence of X_s phase with increasing betatizing temperature.

몽골의 식물 유전자원 연구현황

임무상,바이에르숙,백형진,이석영,이동진 한국국제농업개발학회 1997 韓國國際農業開發學會誌 Vol.9 No.4

몽골에서는 1920년대부터 러시아와 공동으로 식물 유전자원을 탐색, 수집하였으며 이들을 재료로 1950년대부터는 품종을 육성하였다. 다칸의 식물학 및 농업연구소는 1979년에 설립되어 10년 장기계획을 토대로 식물유전자원 연구를 실시하였는바, 다양한 농업생태 지역을 바탕으로 육종모본이 될 작물들을 수집하였다. 현재 다칸의 식물 및 농업연구소에는 밀 8,448점, 보리 4,423점, 귀리 1,672점 등 총 21,132점이 상온에 보존되어 있고 그중에 1,200점은 연구소 자체, 국제기관 또는 국제협력에 의해 수집된 재래종이다. 1991년에는 5개년 계획으로 식물유전자원의 수집, 도입, 안전보존, 평가, 교환, 정보화 및 이용 등에 대하여 진행되고 있다. 이들 자원에 대한 연구는 다칸의 식물학 및 농업연구소를 중심으로 Choibalsan의 동부지역 농업연구소, Hovd의 알타이지역 농업연구소, Ulaangom의 서부지역 농업시험장, 울란바타르의 가축사양연구소 등과 협력적으로 운영되고 있다. 유전자원에 대한 국가적인 전략은 작물의 생산성 향상, 환경내성 품종 육성을 위한 야생근연종 등 다양한 자원의 확보와 현지내의 보존 및 장,단기보존 방법의 개발, 전문가양성 및 외국과의 공동연구를 통한 종자 및 정보의 교환에 역점을 두고 있다. In Mongolia, collection and exploration of traditional crop genetic resources was initiated in 1920s with the assistance of Russian researchers and first local varieties have been developed through breeding programmes. from 1950s With the establishment of Plant Genetic Resources(PGR) Section at Plant Science and Agricultural Research Institute(PSARI) in 1979, comprehensive preservation, exploration and collection of PGR was started on a regular basis and First 10 Year Programme for PGR exploration was launched. The programme involved collection, introduction and exploration of crop genetic resources in different agro-ecological zones to develope initial materials for breeding, enrich crop species with new varieties and identify suitable agroecological zones for crop production. In 1991, a new Five Year National Programme for PGR was started. This programme involved the collection, introduction, preservation, evaluation, exchange, documentation and utilization of PGR. All of the agricultural research institutes of Mongolian National Agricultural University(MNAU) are participating in this programme. In 1992, the National Board of PGRNBPGR) was established to address the urgent need for the coordination of the activities in the managment of PGR in Mongolia.

Anti-lactoferrin IgY 항체의 면역학적 특성과 우유의 락토페린 측정

이승배,최석호,백두연 한국낙농학회 1999 韓國酪農學會誌 Vol.21 No.4

Bifidobacterium bifidum HY 균주의 Genotype 과 Aflatoxin 결착 제거 및 돌연변이 억제 활성

윤영호,백영진 한국낙농학회 1999 韓國酪農學會誌 Vol.21 No.4

Interaction between the Helicobacter pylori CagA and -Pix in Gastric Epithelial AGS Cells

BAEK, H. Y.,WEON LIM, J.,KIM, H. Wiley (Blackwell Publishing) 2007 Annals of the New York Academy of Sciences Vol.1096 No.1

<P>The gastric pathogen Helicobacter pylori (H. pylori) translocates the CagA protein into epithelial cells by a type IV secretion process. Upon translocation into the host cell cytosol, CagA undergoes tyrosine phosphorylation. Phosphorylation of CagA occurs within the C terminus of the protein and is mediated by members of the Src family of tyrosine kinases. Phosphorylation of CagA induces the dephosphorylation of as yet unidentified cellular proteins, rearrangements of the host cell actin cytoskeleton, and cell scattering. This article aims to determine the cellular protein that interacts with CagA. Gastric epithelial AGS cells were stimulated with CagA-positive H. pylori (NCTC11637, at a bacteria/cell ratio of 500:1) and cultured in antibiotic-free medium. Proteins were isolated from the cells with or without H. pylori infection. CagA-interactive protein was determined by immunoprecipitation using anti-CagA antibody and proteomic analysis. We found that alpha-Pix interacts with CagA and alpha-Pix was constitutively expressed in AGS cells. Upon H. pylori stimulation, CagA was translocated into the cells and the expression of alpha-Pix (PAK-interactive exchange factor) was increased in AGS cells time dependently. The interaction of alpha-Pix with CagA was increased by H. pylori infection in AGS cells. Phosphorylation of CagA induces the dephosphorylation of alpha-Pix in AGS cells. alpha-Pix is a family of PAK-binding proteins that strongly activates PAK (p21-activated tyrosine kinase). PAK regulates changes in gene expression and mediates actin cytoskeletal and cell morphological changes. The novel finding of this study is that phosphorylation of CagA induces the dephosphorylation of alpha-Pix, which may modulate cytoskeletal changes of gastric epithelial cells through PAK.</P>