일방향응고 초내열합금 CM186LC의 크리프 및 저주기피로 균열생성

趙昌龍,金豆炫,崔承柱,徐晟文,李在鉉 창원대학교 공작기계기술연구센터 1999 연구업적집 Vol.1 No.1

The second generation DS alloy CM186LC has comparable creep-rupture life to first generation single crystal alloys CMSX-2 and CMSX-3 in the as-cast and double aged condition. In the assembly of nozzle guide vanes, Ds components are joined into pairs by brazing. In order to study mechanical behavior of the material at the same condition as production, DS bars were subjected to brazing simulated treatments. Compared with standard treatment a small drop in creep-rupture life was observed but the degree of fall in life was not serious. Creep cracks initiated at the transverse components of the grain boundaries, which were normal to the applied stress direction. Every crack was associated with the v-v' eutectic phase at grain boundaries v-v' eutectic was not only located at grain boundaries but also in the interdendritic regions. It also acted as crack initiation site during creep. Low cycle fatigue tests were conducted under fully reversed trapezoidal strain wave at a frequency of 0.25Hz. The depth of the LCF cracks at the surface was comparable to that of the secondary dendrite arms from the surf-ace of the specimen. Cracks initiated at all of the interdendritic regions exposed at the surface, especially at the v-v' eutectic phase. LCF crack initiation and propagation are therefore proposed to be microstructally dependent.

초내열합금 CM247LC의 미세조직 및 인장 특성에 미치는 진동 및 접종처리의 영향

徐晟文,芮大喜,金仁守,趙昌龍 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.12

Effects of vibration(V) and inoculation(I) during casting on the microstructure and tensile properties of nickel-base superalloy CM247LC were investigated. The vibration treatment with a frequency of 10 ㎐ was effective to refine the grain size and decrease the microporosity level to some extent. The vibration treatment for the inoculated mold developed the grains of the casting into fine equiaxed grains compared with columnar grains of the casting with vibration free inoculated mold. The existing phases of CM247LC alloy such as finely dispersed cuboidal γ', MC, and grain boundary precipitates were not influenced by the vibration and/or inoculation treatment. The fine equiaxed grained CM247LC had excellent tensile properties compared with those of the columnar grains. The tensile behavior of CM247LC alloy at 760℃ showed different aspects with respect to the grain size change and which was carefully analyzed by fractographic investigations.

솔-젤공정에 의해 기공보정된 한외알루미나 여과막의 기체투과 특성평가

조원준,정은정,이진휘,서성조,서동호 서울産業大學校 1997 논문집 Vol.45 No.1

서로 다른 입자크기의 3층구조를 갖는 튜브형태의 한외알루미나 분리막은, 일반적으로 제조공정중 분리층에 결손부분이 발생하기 때문에 낮은 선택도 및 제거율을 보인다. 이와같은 결손부분을 보정 하고 보정전, 후의 분리막에 대한 기체장치에 의한 투과도(permeability) 및 선택도(selectivity)를 측정하였다. Colloidal silica 솔의 deposition에 기인하여 기체 투과율의 감소가 60%였다. 한외알루미나 여과막의 보정에 있어서 습도조절에 의한 선택적 적심법은 비록 deposition에 의한 문제점을 내포하고 있으나, 기체분리에서도 효과적인 방법이다. The 3-layer tubular type alumina membrane consisting of different pore size shows the decreased selectivity and rejection because of cracks in the separation layer generally occurred during the manufacturing process. For the comparing of native and modified membranes, the modified membranes were tested by permeability by gas equipments, selectivity for the gases after caulking. The permeabilities are decreased 60% for the gas caused by deposition of colloidal silica sol after caulking. In conclusion, the Alternative Wetting Method by humidity control had the effect for the modification of ultrafiltration alumina membrane for separation of gases, though having problem of deposition.

진주 상촌리 공룡발자국 화석의 발굴과 복원

서승조,임성규,박강은 한국환경과학회 2003 한국환경과학회지 Vol.12 No.9

The valuable fossils are distributed in Korean peninsula. In consequence of the development of inland, many road constructions and other public works have been carried out. As a matter of course, lots of paleontological materials in Kyongsang basin were destroyed. Fortunately, one of them was rescued and restored in a suitable place by authors. A fine 4 × 5 m sandstone slab having about 40 dinosaur tracks was brought from Sangchon-ri, Jinju city, and restored at Danghangpo, Goseong County, Gyeongsangnam-do Province. This fossil bearing slab suggests dinosaurs' ecology and paleo-environment during the early Cretaceous Period of Kyongsang basin.

마이크로파 용융삽입법을 이용한 생분해성 나노복합체의 제조

하원조,신준식,송승욱,김준호,손세모,박성수 한국환경과학회 2004 한국환경과학회지 Vol.13 No.4

The purpose of this study was to investigate the possibility of application of microwave energy for the fabrication of polymer/clay nanocomposite. APES/Clay nanocomposites were prepared at 130℃ for 30min with various content of clay by melt-intercalation method under classical and microwave heating source. APES/Clay samples were characterized by the means of X-ray diffractometry(XRD), thermal gravimetric analysis(TGA), and rheometric dynamic analysis(RDA). It was found that intercalated or exfoliated state was obtained in the samples according to the condition of organic modification, clay content, and heating source.

제주도 연안 초망 어선의 소음에 관한 연구

박성욱,서익조,오승훈,김병엽,이창헌,서두옥 濟州大學校 海洋硏究所 2002 해양과환경연구소 연구논문집 Vol.26 No.-

제주도 연안에서 이루어지는 초망 어업에서 수중음을 이용하여 멸치 어군을 유효하게 집어하기 위한 기초 자료를 얻기 위하여 어선의 주기관을 공회전시켰을 때의 선상과 어군이 유집되어 투망되는 수심 4m지점과 함께 수심 10m층의 수중 소음을 측정 조사하였다. 이때 사용한 선박의 공회전은 전진시의 800 rpm과 후진시의 1000 rpm으로 그 결과는 다음과 같다. 1. 기관의 회전수 800 rpm에서 선수(B), 갑판(D), 선미(S), 연돌 위(F), 기관실 내(E)의 소음 준위는 각각 90, 93, 106, 107, 101 dB 이었으며, 기관 회전수 1,000 rpm에서의 소음 준위는 각각 93, 95, 110, 109, 103dB이었다. 2. 회전수를 800rpm으로 할 경우 100, 300, 500, 1000, 1500, 2000 Hz에서 선수의 소음 준위는 4m인 경우 각각 92, 95, 102, 97, 94, 92dB 이었으며, 수심 10m인 경우 87, 88, 99, 96, 94, 93 dB이었고, 선체 중앙에서는 4m인 경우 94, 91, 100, 96, 94, 92dB, 10m인 경우 93, 92, 99, 95, 93, 91dB이었다. 선미에서는 4m인 경우 98, 94, 100, 97, 94, 92 dB이었으며 10 m인 경우 92, 93, 99, 96, 93, 92 dB로 나타났다. 3. 후진시 사용하는 회전수 1000 rpm으로 할 경우 100, 300, 500, 1000, 1500, 2000 Hz에서 선수 소음 준위는 4m인 경우 각각 86, 91, 98, 95, 93, 92 dB로 나타났고, 10m인 경우 88, 87, 99, 96, 94, 92 dB로 나타났으며, 선미에서는 4m인 경우 88, 88, 99, 96, 93, 92 dB, 10m인 경우 88, 86, 99, 96, 94, 92 dB로 나타났다. In order to obtain a basic data for alluring a school of fish, anchovy with emitting underwater sound, an experimnet for measuring noise level was carried out on no-load operation of a engine. noise level was measured at the depths of four meters and ten meters and analyzed. Then, the revolution per minute of the ship used at this field experiment was 800 including 1000. The results were followed. 1. On 800 rpm, noise levels on board were 90, 93, 106, 107 and 101 dB in the order of bow, deck, stern, funnel, funnel and engine room. In addition, 93, 95, 110, 109 and 103 dB on 1000 rpm, respectively. 2. on 800 rpm, underwater noise levels of the depth of four meters at the bow were 92, 95, 102, 97, 94 and 92dB at the frequencies of 100, 300, 500, 1000, 1500 and 2000 Hz, respectively and those of the depth of ten meters were 87, 88, 99, 96, 94 and 93 dB. Underwater noise levels of the depth of four meters outside the engine room were 94, 91, 100, 96, 94 and 92 dB at the frequencies of 100, 300, 500, 1000, 1500 and 2000 Hz, respectively and those of the depth of ten meters were 93, 92, 99, 95, 93 and 91 dB. Underwater noise levels of the depth of four meters at the stern were 98, 94, 100, 97, 94 and 92 dB at the frequencies of 100, 300, 500, 1000, 1500, and 2000 Hz, respectively and those of the depth of ten meters were 92, 93, 99, 96, 93 and 92 dB. 3. On 1000 rpm, underwater noise levels of the depth of four meters at the bow were 86, 91, 98, 95, 93 and 92 dB at the frequencies of 100, 300, 500, 1000, 1500 and 2000 Hz, respectively and those of the depth of ten meters were 88, 87, 99, 96, 94 and 92 dB. Underwater noise levels of the depth of four meters at the stern were 88, 88, 99, 96, 93 and 92 dB at the frequencies of 100, 300, 500, 1000, 1500 and 2000 Hz, respectively and those of the depth of ten meters were 88, 86, 99, 96, 94 and 92 dB.

란크릭 캅셀(플루옥세틴 20mg)에 대한 프로작 캅셀의 생물학적 동등성 시험

심상범,조요나,오한석,류재환,이경태,김남재,서성훈 경희대학교 동서의학연구소 2001 東西醫學硏究所 論文集 Vol.2000 No.-

Bioequivalence of two flouxetine capsule, ProzacR (Lilly kora Ltd.) and LanclicR (Samsung Pharm. IND. Co.), was evalated according to the guideline of KFDA. Twenty four healthy male volunteers (21-26 years old) were divided into two groups and a randomized 2×2 cross-over study was employed. After 60mg of fluoxetine was orally administered, blood was taken at 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 24, 32, 48 and 72 hours after administration and just before administration. Plasma was analyzed for fluoxetine and internal standard (clomipramine) by a sensitive and validated HPLC assay. The pharmaco kinetic parameters (AUCt, Cmax and Tmax) wre calculated and ANOVA test was used for the statistical analysis of parameters. Differences in (AUCt, Cmax and Tmax between two capsules were -0.90, 3.46 and -14.08% respectively. All powers (1-β) for AUGt, Cmax and Tmax were more than 0.9. Detectable differences (Δ) and confidence interval were all less than ±20%. All the parameters above met the criteria of KFDA for bioequivalence and indicated that LanclicR capsules are bioequivalent to ProzacR capsules.

초내열합금 B1900의 미세조직과 인장특성에 미치는 고온노출의 영향

김인수,최백규,서성문,조창용 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.7

Influence of thermal exposure on microstructural evolution and tensile properties of Ni-base superalloy B1900 has been investigated. Phase transformations during thermal exposure and their effects on tensile behavior of the alloy have been analyzed by microstructural observations. Considerable amount of acicular type M_(6)C carbide precipitated in the interdendritic regions (including γ/γ' eutectic) and in the vicinity of MC carbide as a result of thermal exposure above 871°C. Thermal exposure also assisted precipitation of small discrete M_(23)C_(6) carbide which is hard to be found in the alloy. Thermal exposure deteriorated tensile properties of the alloy. The effect of M_(6)C precipitation on the tensile properties of the alloy is not clear. However, degradation of tensile properties of the alloy is primarily attributed to the coarsening of y' phase during thermal exposure. While the localized deformation bands were observed in the as-cast tensile specimen due to shearing of γ' particle, dislocation network formed at γ/γ'interface in the thermally exposed tensile specimen.

제주 연안산 잿방어의 청각특성에 관한 기초적 연구

서익조 ( Yik Jo Seo ),김성후 ( Seong Ho Kim ),김병엽 ( Byong Yop Kim ),이창헌 ( Chang Heon Lee ),서두옥 ( Du Ok Seo ) 한국어업기술학회 2003 수산해양기술연구 Vol.39 No.4

Isotope correlation technique for Pu mass analysis of PWR UO2 spent fuel rods

Seo, Hee,Ahn, Seong-Kyu,Han, Bo-Young,Lee, Chaehun,Shin, Hee-Sung,Kim, Bong Young,Lee, Seung Kyu,Won, Byung-Hee,Jo, Kwang Ho,Kim, Ho-Dong,Park, Geun-Il,Park, Se-Hwan Atomic Energy Society of Japan 2016 Journal of nuclear science and technology Vol.53 No.10

<P>A simple and fast method of nuclear material accountancy of pressurized water reactor (PWR) UO2 spent fuel rods for safeguards application was developed utilizing the isotope correlation between the amounts of Cs-137 and total Pu. To this end, the following steps were taken: (1) as much destructive analysis (DA) data as possible for segments taken from a PWR UO2 spent fuel rod were aggregated from publicly available data sources; (2) the DA data were corrected so as to have the same cooling time (i.e., CT = 0 y) and analyzed for outliers; (3) an equation converting the Cs-137 amount to the Pu amount was obtained by regression analysis with logarithmic curve fitting; and (4) the error in determining the Pu amount was evaluated for the imposition of a limit on the range of burnup (BU) or initial enrichment (IE). It was found that the averaged % error in calibration was determined to be 3.88% +/- 2.68% (= mean +/- 1 standard deviation) for the BU range over 30GWd/tU and falling with increasing BU range. On the other hand, there was no benefit in applying the limit of the IE range. Lastly, the Pu-mass difference between various methods was compared and it was found that the difference can be incurred up to 11.4%, according to the choice of method. In conclusion, the proposed isotope correlation technique could be used for input material accountancy with reasonable uncertainty.</P>