신명기 역사에 나타난 바알종교

오택현 연세대학교 신과대학 2001 신학논단 Vol.29 No.-

Martensite 체적분률에 따른 복합조직강의 인장강도 및 Void형성과 성장에 관한 연구

吳澤烈,金斗英 慶熙大學校 材料科學技術硏究所 1991 材料科學技術硏究論集 Vol.4 No.-

The mechanical properties of ferrite-martensite dual phase steel are affected by the microstuctural factors such as the martensite volume fraction, grain size of ferrite, strength ratio of ferrite-martensite, connectivity and chemical components, etc. Therefore, by means of the heat treatment of low carbon steel (SM20C), this study deals with the tensile strength and void formation, growth for martensite volume fraction of dual phase steel. The results obtained could be summarized as follow : ⅰ) The tensile strength increased by increasing martensite volume fraction in dual phase steel. And experimental strength made a differerence in theorectical strength in low martensite volume fractionm, but it accorded with that in high martensite volume fraction. ⅱ) The void formation, growth in dual phase steel occured in the onset of plastic deformation. Voids were observed more at martensite/martensite than at ferrite/martensite interface. The longest void was observed near at noting surface, the rate of increase for the longest void is much larger than that for average void size. According to strain, the number of voids increase in low strain, and then decrease in high strain(0.4 over) because of void coalescence. ⅲ) Under martensite volume fraction 60%, fraction mode of dual phase steel showed ductile fracture. Over martensite volume fraction 60%, there was shear fracture mode which had the rate of fast crack propagation. Therefore, beyond martensite volume fraction 60%, dual phase steel is not good for the use of Engineering.

보이드 생성기구에 의한 복합조직강의 연성 파괴거동에 관한 연구

吳澤烈,崔明振,楡龍錫,金松正 慶熙大學校 材料科學技術硏究所 1993 材料科學技術硏究論集 Vol.6 No.-

Ductile Fracture of Dual Pase Steel begins with void nucleation, at Martensite-Ferrite interface or deformed Martensite particle. In this study void nucleation, void growth, void volume fraction and void coalescence at given strain were studied in dual phase steel. Therefore, by means of the heat treatment of low corbon steel the study deal with void nucleation and void growth for ferrite grain sizeof dual phase steel. Void nucleaton and void growth with increasing strain are shown depend upon the ferrit grain size. The number of voids and volume fraction of voids generary increase as ferrite grain size decrease. At the close to fracture the void coalescence in the direction of the applied tensile stress, but near the fracture surface they linked in direction transverse to the tensile axis.

레이저를 이용한 Tailored Blank 용접 판재의 피로거동

오택열,권윤기,이종재,곽대순 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.4

For the Tailor Welded Blank sheet used for automobile body panel, the characteristics of fatigue strength and crack propagation behavior were studied. The thickness of specimen was joined to be same (0.9mm+0.9mm) and different (0.9mm+2.0mm). As a base test, mechanical properties around weld zone were examined. The results indicated that there were no significant decreases in mechanical properties, but hardness around weld bead was 2.3 times greater than base material. The fatigue strength was the highest when the loading direction was parallel to the welding direction, which was about 85% of tensile strength of base metal. It was decreased by 8.5% when the thickness of specimen and base metal was different, and it was increased by 25% when pre-strain was applied. The crack propagation rate was noticeably decreased around weld line and rapidly increased as it passed through weld line. Reviewing the shape of the crack propagation, crack width around weld line was wide around the weld zone due to retardation of crack growth, but it became narrow passing weld line due to decreased toughness.

유한요소법을 이용한 복합조직강의 경도비 변화에 따른 응력-변형거동에 관한연구

吳澤烈,張現貴 慶熙大學校 材料科學技術硏究所 1992 材料科學技術硏究論集 Vol.5 No.-

Mechanical properties of dual phase steel are affected by the microstructural factor, such as, martensite volume fraction, grain size of ferrite, hardeness ratio of ferrite-martensite, connectivity and chemical properties. In this study, the tensile test was carried out to analyze the tensile characteristic of the Ferrite-Martensite dual phase steel with the Hardeness Ratio of four kinds. The result obtained could be summarized as follow ; The calculated Stress-Strain curves for four hardeness ratios were compared with their corresponding experimental curves, and in general, good agreements were found. After tensile tests were done at various tempering temperatures, we had a result that the tensile strength at 200℃ was the largest. It was found that for a given hardeness ratio, the calculated stress-strain curve was higher than experimental curve. The more reduce the hardeness ratio, the more narrow the gaps between the experimental curve and the calculated curve. It is related with the plastic constraint factor K.

제2이사야와 신명기 역사에 반영된 바벨론 제국의 상황

吳澤弦 연세대학교 신과대학 1999 신학논단 Vol.26 No.-

複合組織鋼의 衝擊擧動에 關한 實驗的 硏究

吳澤烈 慶熙大學校 1984 論文集 Vol.13 No.-

This study has been made of analysis on the influence of micro-structure which releates to impact behavior of dual-phase(D.P.) steel. Some important conclusions obtained from this study are summerized in the following 1. Martensite encapsulated islands of ferrite (MEF Microstructure) satisfied the Hall-Petch relation well. In the case of Ferrite encapsulated islands of ferrite (FEM Microstructure), it didn't satisfy the relation when Impact velocity was law. According to the increase of impact velocity, however, both materials became satisfied the Hall-Petch relation completely. 2. The more matrix grain size was minute, the more maximum load was increased. And maximum load of MEF structure was higher than FEM structure. 3. Loading time of FEM structure was longer than FEM structure, and large matrix grain size prolonged the loading time. 4. Fracture toughness increased when matrix grain size became minute and martensite came to more isolated. 5. The reason that strength of MEF structure is higher than FEM structure is due to the restraint effect of plastic deformation of MEF structure.

複合組織鋼의 引張强度特性에 관한 硏究

吳澤烈 慶熙大學校 1986 論文集 Vol.15 No.-

A study has made of the tensile characteristics of dual phase(martensite plus ferrite) steels produced when a low carbon steel is quenched from either the austenite of austenite plus ferrite phase fields. The results can be summarized as follows; 1. The hardness ratio of second phase martensite to ferrite phase and reduction of area are decreased with increasing the martensite volume fraction when dual phase structures are made of a steel having the same composition. 2. Ductile fracture decreases when the intercritical temperature is increased and martensite hardness is decreased, because of the composite hardness increasing with increasing the intercritical temperature. 3. Tensile and yield strength of dual phase steel are function of martensite volume fraction, and the yield ratio showed relative low values. 4. The morphology of martensite in a low carbon steel through the step quenching is a lath type, and the true uniform strain is decreased according to the increase of martensite volume fraction, but it is higher than HSLA steel in the same strength level.

한국산 감귤 수입 예상국의 수입 검역제도에 관한 연구

김택조,강영길,권오균 濟州大學校 亞熱帶農業硏究所 1995 亞熱帶農業硏究 Vol.12 No.-

수출밀감 생산지와 밀감 수출관련기관에 유용한 정보를 제공하고자 제주산 온주밀감 주요수입국 및 수입가능국의 검역제도를 조사분석한 결과를 요약하면 다음과 같다. 1. 조사대상국의 연간 수입량은 캐나다 61.5천톤, 미국 101.1천톤, 일본 1.2천톤, 홍콩 32.3천톤 정도이었고 1993년 한국산 감귤 수입량은 캐나다 1107톤, 홍콩 6톤, 러시아가 150톤이었다. 2. 캐나다는 병충해 위험도 평가를 실시한 후 한국산 밀감을 식물위생증이나 수입허가서 없이 수입하고 있다. 수입검사 중 캐나다에 분포하는 병해충으로서 감염정도가 심하지 않은 식물류는 소독처리하고 캐나다에 분포하지 않은 병해충이나 분포하는 병해충이라도 감염이 심한 경우 폐기 (반송)된다. 한국산 밀감의 경우 부패과를 제외하고는 검역상 문제가 되지 않고 있다. 3. 미국은 수입허가제를 채택하고 있으며 한국산 밀감은 궤양병, 흑반병, 화살깍지벌레의 미국내 유입을 막기위하여 수입이 금지되고 있으나 궤양병 무병 생산단지 및 완충지대 설정, 과실의 예방적 소독처리, 박테리아제 테스트 실시, 선과 후 안전조치등을 조건으로 미국내 수입이 한미간 합의 되었다. 과실의 채소류의 반입항에서 수입물량의 약 2%의 임의 표본 추출하여 검사하며, 미국에 분포하는 병해충만이 검출되는 경우에는 수입이 가능한 반면 검역대상 병해충이 발견될 때 소독방법이 있을 경우에는 소독하고 소독방법이 없을 경우에는 폐기 또는 수입이 거부된다. 4. 일본은 14종의 금지병해충의 기주식물 및 식물성 생산물의 수입을 금지하고 있으나 한국산은 수입금지품에 해당되는 식물이 없다. 금지병해충 (14종)과 특정 중요병해충 (42종)이 부착된 식물중 효과적인 소독방법이 확립되어 있지 않은 과실은 폐기되고 소독가능 병해충이 발견된 과실류는 소독되거나 선별된다. 5. 홍콩에서의 수입 비제한 품목인 과실 및 채소류는 식물위생증이나 수입허가서 없이 수입되며 수입검사중 병해충이 발견되면 소독처리된다. 6. 러시아에서는 수입비제한 품목을 제외하고는 식물 및 식물성 산물의 수입시 식물위생증과 수입허가서가 요구되며 허가항을 통하여 수입되어져야 한다. 7. 감귤류가 재배되지 않아 수입검역이 까다롭지 않은 캐나다, 홍콩, 러시아의 동부에 한국산 밀감 수출 증대를 도모하는 것이 바람직하다. This study was conducted to obtain knowledge of import quarantine system in Canada, the U.S.A., Japan, Hongkong and Russia, which may facilitate export Korean mandarins to these countries. The results are summarized as follows : 1. Canada, the U.S.A., Japan, Hongkong annually import about 61,500, 101,100, 1,200 and 32,300 tons. respectively, of such citrus fruits as mandarins, tangerines and clementines. In 1993, 1,107 tons of Korean mandarins were imported into Canada, 6 tones into Hongkong and 150 tones into Russia. 2. After pest risk on Korea mandarins for Canada was assessed, the mandarins have been imported into Canada without phytosanitary certificate and import permit. When either diseases and/or pests which have occurred in Canada are found or they are not severe during import inspection, disinfection is ordered. When either diseases and/or pests which have never occurred in the country are found or they are severe, the importer is ordered to destroy or reship the shipment. In Canada, import quarantine for Korean mandarins has been smooth except the rotten fruits have been found. 3. The import of Korean mandarins into the U.S.A. is prohibited to prevent citrus caker, phoma rot and arrowhead scale from being introduced into the U.S.A. However, it has been agreed between Korea and the U.S.A. that there can be imports into the U.S.A. of mandarins from Chejudo based on implementation of certain procedures. At the ports of entry, inspections are conducted by sampling about 2% of the imported amount of fruits and vegetabls. When injurious diseases and/or pests are found, disinfection is ordered. When there is no methods of disinfection which can completely kill the diseases and/or pests, the importer is ordered to destroy or reship the shipment. 4. Prohibited are host plants and plant products of 14 kinds of diseases and pests that have never occurred in Japan. In import inspection, when diseases and/or pests are found, disinfection is ordered. When there is no methods of disinfection which can completely kill the diseases and/or pests. the importer is ordered to destroy or reship the shipment. 5. Fresh fruits and vegetable can be imported into Hongkong without phytosanitary certificate and import permit. When diseases and/or pests are found during import inspection, disinfection is ordered. 6. Phytosanitary certificate permit are required in Russia for import of plants and plant products from foreign countries. The port of entry is designated by the quarantine authorities. It seems to be desirable to try hard to increase export amount of Korean mandarins to Canada, eastern Russia and Hongkong which do not raise citrus fruits and are not strict for import quarantine of citrus fruits.

화학기상응축 공정으로 제조한 Fe 나노입자의 TEM 미세조직 및 결정화거동

김택수,이희정,오익현,한재길,최철진,이병택 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.12

Iron and iron nitride nanoparticles were synthesized by chemical vapor condensation (CVC) process, using a precursor of Fe(CO)_(5) and carrier gas of NH₃. Phase change and crystallization behaviors of as received particles were mainly examined by TEM technique. Only α-Fe nanoparticles were formed at the lowest decomposition temperature of 500℃. As the temperature increased, the crystallization of α-Fe nanoparticles was suppressed and Fe₃N nanoparticles were begun to be formed. Finally full crystallization of Fe₃N was observed at 1000℃. Typical size of the α-Fe and Fe₃N particles was less than 30 nm in diameter.