Bi_1/2Na_1/2TiO₃-BiAlO₃ 무연 압전 세라믹스의 유전 및 전기 기계적 변형 특성에 대한 SrTiO₃ 첨가 효과

이상섭,이창헌,즈엉 짱 안,김동혁,김병우,한형수,이재신,Lee, Sang Sub,Lee, Chang-Heon,Duong, Trang An,Kim, Dong Hyeok,Kim, Byeong Woo,Han, Hyoung-Su,Lee, Jae-Shin 한국재료학회 2021 한국재료학회지 Vol.31 No.10

(Bi_1/2Na_1/2)TiO₃ (BNT)-based ceramics are considered promising candidates for actuator application owing to their excellent electromechanical strain properties However, to obtain large strain properties, there remain several issues such as thermal stability and high operating fields. Therefore, this study investigates a reduction of operating field in (0.98-x)Bi_1/2Na_1/2TiO₃-0.02 BiAlO₃-xSrTiO₃ (BNT-2BA-100xST, x = 0.20, 0.21, 0.22, 0.23, and 0.24) via analyses of the microstructure, crystal structure, dielectric, polarization, ferroelectric and electromechanical strain properties. The average grain size of BNT-${\underline{2}}$BA-100xST ceramics decreases with increasing ST content. Results of polarization and electromechanical strain properties indicate that a ferroelectric to relaxor state transition is induced by ST modification. As a consequence, a large electromechanical strain of 592 pm/V is obtained at a relatively low electric field of 4 kV/mm in 22 mol% ST-modified BNT-2BA ceramics. We believe that the materials synthesized in this study are promising candidates for actuator applications.

Bi_0.5Na_0.5TiO₃-BiFeO₃-SrTiO₃ 삼성분계 무연 압전 세라믹스의 강유전체-완화형 강유전체 상전이 거동

이상섭,이창헌,즈엉 짱 안,웬 호앙 티엔 코이,한형수,이재신,Lee, Sang Sub,Lee, Chang-Heon,Duong, Trang An,Nguyen, Hoang Thien Khoi,Han, Hyoung-Su,Lee, Jae-Shin 한국전기전자재료학회 2021 전기전자재료학회논문지 Vol.34 No.1

This study investigated the structural, dielectric, ferroelectric, and strain properties of (0.98-x)Bi1/2Na1/2TiO3-0.02BiFeO3-xSrTiO3 (BNT-BF-100xST, x＝0.20, 0.22, 0.24, 0.26, and 0.28). All samples were successfully synthesized using the conventional solid-state reaction method and sintered at 1,175℃ for 2 h. The average grain size of the BNT-BF-100x ceramics decreased with increasing ST content. Furthermore, we observed that the ferroelectric- relaxor transition temperature (TF-R) decreased with increasing ST content, which eventually vanished in the BNT-BF-24ST ceramics. The results indicated that a ferroelectric to relaxor phase transition could be induced by ST modification. Consequently, a large electromechanical strain of 633 pm/V at 4 kV/mm was observed for the BNT-BF-26ST ceramics. These results imply that our materials have the competitive advantage of larger strain under lower operating field conditions compared with other BNT-based lead-free piezoelectric ceramics. We expect that BNT-BF-ST lead-free piezoelectric ceramics are promising candidates as a novel ternary BNT-based system and can find potential applications in actuators.

한약의 전이재발억제 효과에 관한 연구

이상섭,유화승,조정효,손창규,이연월,조종관,Lee, Sang-Seob,Yoo, Hwa-Seung,Cho, Jung-Hyo,Son, Chang-Kyu,Lee, Yeon-Weol,Cho, Chong-Kwan 대한암한의학회 2003 大韓癌韓醫學會誌 Vol.9 No.1

Recently, the occurrence and death rates of cancer have increased rapidly. Metastasis and recurrence is the most important factor of death from cancer. So inhibition of recurrence and metastasis can increase the cure rate of cancer disease. At the basic chinese traditional medicine(TCM), there are a lot of theory related to neoplasm treatment. The metastasis and recurrence of neoplasm was the basis of yudu(餘毒) on remained neoplasm cell and stagnation of blood, thermotoxo, phlegm, asthenia of healthy enerngy and stagnation of vital energy. The principles therapy of neoplasm on metastasis and recurrence was based on knowledge of the method of support the healthy energy and strengthen the body resistance, promote blood circulation to remove blood stasis, clear away heat and toxic materials, dissipate phlegm and disperse the accumulation of evils. But the major clinical features of neoplasm was to be considered in developing a treatment plan include (1) distinguish between clinical and pathologic staging - acute and chronic, (2) classification of pathologic pattern, and (3) distingction of body situation : for examples asthenia - sthenia etc. It was most important to distinguish between supporting the healthy and eliminating the evil factors and to treat differently at the root and the branch cause of a neoplasm. This paper's results indicate that identification and effective use of THM can inhibite netastasis and recurrence and then it will help increasing survival rate. Also as BioTechnology(BT) has developed rapidly nowadays, as genes related to cancer have revealed. So it will give rise to the development of searching the mechanism of herb medicines which have inhibition effects of metastasis and recurrence.

송년에세이

이상섭,Lee, Sang-Seop 대한출판문화협회 1992 출판저널 Vol.118 No.-

Molecular Level Relationships of Purple Nonsulfur Bacteria and their Relatives

이상섭,윤병수,김재수,이현순,Lee, Sang-Seob,Yoon, Byoung-Su,Kim, Jae-Soo,Lee, Hyun-Soon The Microbiological Society of Korea 1994 미생물학회지 Vol.32 No.1

광합성 세균과 비광합성 세균에 속하는 종들 사이의 유연관계를 파악하기 위해 DNA 혼성화 방법을 실시하였다. 혼성화도는 종내 균주들 사이와 Rhodobacter capsulatus와 Rhodopseudomonas blastica 사이를(72-88%) 제외하고는 전체적으로 낮게 나타났다(2-35%). 광합성 세균 Rhodopseudommonas Palustris와 비광합성 세균 Pseudomonas aeruginosa ATCC 27853, Bradyrhizobium japonicu, 사이의 D%는 광합성 세균 사이의 D%보다 약간 높게 나타났다(26-33%). Rhodopseudomonas blastica와 Rhodobacter capsulatus 사이의 D%는 72%로 유전적 유연관계가 매우 높은 것으로 나타났다. DNA-DNA hybridization by kinetic method was carried out between species of purple nonsulfur photosynthetic bacteria and nonphotosynthetic bacteria. The degrees of homology percent were shown to be low (2-35 D%) with the exception of high homology % (72-88 D%) for strains within a species and between Rhodobacter capsulatus and Rhodopseudomonas blastica. The D% between the purple nonsulfur photosynthetic bacteria, Rhodopseudomonas palustris, and nonphotosynthetic bacteria, Pseudomonas aeruginosa ATCC 27853 or Bradyrhizobium japonicum were a little higher (26-33 D%) than the D% between any other photosynthetic bacteria. The homology % between Rhodopseudomonas blastica and Rhodobacter capsulatus was 72 D%, which showed genetic relationship.

제9회 국제 항공우주 심포지엄 및 무기체계 전시회 개최

이상섭,Lee, Sang-Seop 한국항공우주산업진흥협회 2000 航空宇宙 Vol.73 No.-

대학순례-지역발전의 견인차, 동신대학교

이상섭,Lee, Sang-Seop 한국대학교육협의회 1995 大學敎育 Vol.73 No.-

Biodegradation Mechanims of Capsaicin and its Analogs(I) Microbial-$\omega$-Hydroxylation on Capsaicin Mixture

이상섭,유인순,Lee, Sang-Sup,You, In-Soon 생화학분자생물학회 1977 한국생화학회지 Vol.10 No.3

고추의 매운 성분 Capsaicin혼합체(capsaicin과 dihydrocapsaicin의 혼정)를 Aspergillus niger의 배양액 중에 첨가하면 Capsaicin은 매운 맛이 없어지고 극성이 강한 phenol성 물질로 전환된다. 이 전환된 물질을 확인하기 위하여 한국산 고추에서 분리한 Capsaicin 혼정 1g를 발효시킨후 배양액을 추출하고 silicic acid column chromatography를 행하여 360 mg의 유상 물질을 분리하였다. 이 물질중에는 vanillylamide 부분이 있다는것을 Capsaicin 표준폼의 UV 흡수 spectrum과 비교하여 확인하였다. 또한 이 물질과 표준 Capsaicin의 NMR signal를 비교하면 Capsaicin중의 직쇄(side chain) 말단에 있는 isopropyl부분의 methylproton($\tau$9.5)의 일부가 사라지고 대신 hydroxymethyl기의 두 methylene proton($\tau$ 6.5)이 새로 나타났다. 이 유상 물질은 acetate로 만들어 결정화 시키고 다시 NMR, IR, GC로 분석하였다. 이러한 결과를 종합하여 Capsaicin 혼합체의 A. niger에 의한 미생물학적 대사 물질은 $\omega$-hydroxy화합물인 trans-8-hydroxymethyl-N-vanillyl-6-nonenamide와 8-hydroxymethyl-N-vanillylnonanamide인 것을 증명하였다. When a capsaicin mixture (capsaicin and dihydrocapsaicin) was exposed to Aspergillus niger, it was transformed to more polar phenolic compounds. In order to characterize the main transformed compound, one gram of capsaicin mixture was fermented and the culture broth was extracted. After silicic acid column chromatography, 360mg of of oily product was isolated. The presence of vanillyl amide moiety in the product was confirmed by comparison of the pattern of UV absorption spectrum with of authentic capsaicin. When NMR signals of the product were compared with capsaicin, a new signal ($\tau$6.5) corresponding to the two methylene protons of hydroxymethyl group appeared at the expense of methyl protons of terminal isopropyl group of capsaicin ($\tau$9.5). The oily product was derivatized to its acetate. The acetate was also analyzed by NMR, IR, and GC. It was proved that the transformation product of capsaicin mixture was a mixture of two compounds; trans-8-hydroxymethyl-N-vanillyl-6-nonenamide and 8-hydroxymethyl-N-vanillylnonanamide.

복합스터드의 압축 좌굴 거동

이상섭,배규웅,Lee, Sang Sup,Bae, Kyu Woong 한국강구조학회 2004 韓國鋼構造學會 論文集 Vol.16 No.5

유럽을 중심으로 스틸스터드의 약점으로 지목 받고 있는 열교현상을 억제하기 위한 스터드 개선 연구가 활발히 진행되고 있다. 이 연구는 크게 마감재와 접촉 면적을 줄이는 방법, 웨브면에서 열전달 경로를 늘이는 방법, 열전도성이 낮은 소재를 사용하는 방법, 그리고 스터드를 피복하는 방법으로 구분할 수 있다. 비교적 저층의 주거용 건축물을 대상으로 하는 국외의 경우 에너지 소비에 초점이 맞춰져 있지만, 본 연구의 경우 중층화를 대비하여 구조적 성능도 고려하여 아연도금강판(SGC58)과 FRP를 에폭시로 부착하여 150SL 형태의 복합스터드를 개발하였다. 복합스터드의 소재로는 두께 1.0mm과 1.2mm 강판과 두께 4mm(4ply), 6mm(6ply)의 FRP를 적용하였고, 4가지의 접합 상세에 대한 제작 및 실험을 통해 최종적으로 우수한 결과를 보인 2가지를 선택하였다. 이와 같은 과정을 거쳐 개발된 복합스터드의 압축 성능을 확인하기 위해 2가지 접합 상세에 대해 단면 높이인 150mm에 대해 3, 6, 9, 12배 길이에 대해 압축 실험을 계획하였고, 기존 스틸 스터드와 비교하기 위하여 동일 형태의 비교 실험체도 제작하였다. 실험결과, 복합스터드의 최대하중은 강판 두께 1.0mm인 경우 동일 두께의 스틸 스터드보다 평균 1.62배, 1.2mm인 경우 평균 1.46배 증가하였으며, 가력 종료 시점에 이르기까지 일체 거동을 보여 구조적으로 우수함이 입증되었다. An investigation was conducted on the activities around Europe in order to solve the problem of the thermal bridging of steel studs, which had caused a significant disadvantage. This study included the following: diminishing the contact area between the studs and the sheathing, lengthening the heat transfer route, replacing the steel web with a less conductive material, and placing foam insulation in locations where the thermal shorts are most critical. Although energy efficiency is usually the focus of such foreign cases because their stud application is mostly limited to low-rise residential buildings, both structural and thermal performance are taken into consideration in this study because these target middle-story buildings. A hybrid stud composed of steel and polymer was also developed. This hybrid stud, which is 150 SL in size, is made of a galvanized steel sheet (SGC58) and a glass fiber reinforced polymer (GFRP) withepoxy bonding. A total of 32 specimens were manufactured. Its parameters comprise two types of connection detail,s: the thickness of steel (1.0mm and 1.2mm) and of the GFRP (4mm-4ply and 6mm-6ply), and the ratio of the length to the depth (L/D = 3, 6, 9, 12). Steel stud specimens with the same conditions were compared to the hybrid stud. The test revealed that in the case of the steel specimen with a thickness of 1.0mm, the maximum load of hybrid studs increased an average of 1.62 times comparedto that of the steel stud. In the case of the steel specimen with a thickness of 1.2mm, on the other hand, the average increase was 1.46times. All specimens showed full composite action until the collapse.

경량기포모르터와 합성한 경량형강 벽체의 전단 저항

이상섭,배규웅,Lee, Sang Sup,Bae, Kyu Woong 한국강구조학회 2004 韓國鋼構造學會 論文集 Vol.16 No.4

본 논문은 경량형강으로 제작한 프레임에 경량기포모르터를 채운 경량합성벽체의 전단 거동에 대한 실험 결과와 전단 강도 및 강성 평가를 제시한 것이다. 경량기포모르터는 스틸하우스 벽체의 구조 성능 및 단열 성능의 향상과 마감에 대한 시공성 개선을 위해 도입되었다. 연구 결과 단열 성능에 대한 기여도는 낮으나, 경량기포모르터의 슬러리 비중이 0.8 이상인 경우 구조 성능의 향상과 마감성이 좋은 것으로 나타났다. 본 연구에서는 전단 거동에 미치는 경량기포모르터의 영향을 알아보기 위해 경량기포모르터의 비중(0.6, 0.8, 1.0, 1.2) 벽체의 스터드 배치간격(450mm, 600mm, 900mm), 마감재(경량기포모르터, OSB, 석고보드) 및 브레이싱 등을 변수로 한 14개의 경량합성벽체를 제작하였고 비교를 위해 대표적인 스틸하우스 벽체 3개를 제작하였다. 면내전단 실험결과, 경량기포모르터를 타설한 경량합성벽체가 기존의 스틸스터드 벽체에 비해 최대 내력은 1.15~5.38배, 초기강성은 1.45~13.7배 증가한 것으로 나타났다. 또한 벽체 내부의 스터드를 900mm까지 확장하여도 무리가 없는 것으로 나타났다. 그러나 이와 같은 결과는 건조수축 균열이 억제되지 않은 상태에서 나온 것으로 경량합성벽체의 내력을 향상시키기 위해서는 경량기포모르터의 초기 건조수축균열을 억제하고 스터드와 경량기포모르터 사이의 부착력을 확보하는 것이 무엇보다도 중요한 것으로 나타났다. This paper presents the test and evaluation results on the shear strength and stiffness of a light steel stud wall from a lightweight foamed mortar (lightweight hybrid wall). The use of a lightweight foamed mortar was aimed at improving structural performance, thermal performance, and finish. Studiesshowed that it did not affect thermal performance, but it contributed to structural performance and finish when the unit weight was more than 0.8 (Editor's note: Please indicate the unit of measurement.). In this study, 14 specimens-whose parameters included the specific gravity of the lightweight foamed mortar (0.6, 0.8, 1.0, 1.2), the spacing of the stud (450 mm, 600 mm, or 900 mm), finishing materials (such as lightweight foamed mortar, OSB, and gypsum board), and bracing-were manufactured. Three typical, steel house-framing specimens were added to compare the test results with the 14 specimens. The results of in-plane shear tests show that the use of lightweight foamed mortar (1.15~5.38 times stronger, 1.45~13.7 times stiffer) results in ultimate strength and initial stiffness. In addition, it was possible to widen the stud spacing to up to 900 mm without decreasing shear strength. It was very important to prevent the lightweight foamed mortar from shrinking and to secure the adhesion between the steel stud and the lightweight foamed mortar to improve structural performance.