Effect of Mn and C on Age Hardening of Fe–Mn–Al–C Lightweight Steels

Sung‑Won Park,Jun Young Park,Kyong Mox Cho,Jae Hoon Jang,Seong‑Jun Park,Joonoh Moon,Tae‑Ho Lee,Jong‑Ho Shin 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.3

The effects of Mn and C content on the age hardening of Fe–Mn–Al–C lightweight steels, which have austenitic or duplex(austenite and ferrite) microstructures, were investigated. An increase in Mn content induced a delay of the age hardeningthat is caused by the formation of intra-granular κ-carbides. In order to interpret the effect of Mn content, first-principlescalculations were conducted using the supercells of Fe24Al8C8,Fe24Al8C7,Fe24(Al7Mn)C8, and Fe24(Al7Mn)C7. The calculationsshowed that an increase in Mn content could be the source of the delay of the intra-granular κ-carbide formation bysuppressing C atom’ occupation of the vacancy at the body-centered site of L12. An increase in C content accelerated theformation of intra-granular κ-carbides, which induced the intense age hardening, and coarse inter-granular κ-carbides, whichresulted in significant decrease in impact absorbed energy due to inter-granular fracture.

The Needs as Perceived by Korean Elementary School Teachers and Administrators in School-based Staff Development

Lee,Tae-Sang 한국교육행정학회 2003 敎育行政學硏究 Vol.21 No.2

Artificial Neural Network for Modeling the Tensile Properties of Ferrite-Pearlite Steels: Relative Importance of Alloying Elements and Microstructural Factors

Tae‑Woon Hong,Sang‑In Lee,Jae‑Hyeok Shim,Myoung‑Gyu Lee,Joonho Lee,Byoungchul Hwang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

An artificial neural network (ANN) model was developed to predict the tensile properties as a function of alloying elementand microstructural factor of ferrite-pearlite steels. The input parameters of the model were composed of alloying elements(Mn, Si, Al, Nb, Ti, and V) and microstructural factors (pearlite fraction, ferrite grain size, interlamellar spacing, and cementitethickness), while the output parameters of the model were yield strength and tensile strength. Although the ferrite-pearlitesteels have complex relationships among the alloying elements, microstructural factors, and tensile properties, the ANNmodel predictions were found to be more accurate with experimental results than the existing equation model. In the presentstudy the individual effect of input parameters on the tensile properties was quantitatively estimated with the help of theaverage index of the relative importance for alloying elements as well as microstructural factors. The ANN model attemptedfrom the metallurgical points of view is expected to be useful for designing new steels having required mechanical properties.

Thermoelectric Properties of Bi2Te3 Film Processed by Electrodeposition

Lee, Kwang-Yong,Oh, Tae-Sung Research Institute of Science and Technology HONGI 2005 Hongik Journal of Science and Technology Vol.9 No.-

Thermoelectric properties of the electrodeposited Bi_(2)Te_(3) films have been investigated. Bi_(2)Te_(3) plating solution of 20 mM concentration was prepared by dissolving Bi_(2)O_(3) and TeO_(2) into 1M HNO_(3). Thermoelectric properties of the electroplated Bi_(2)Te_(3) films were changed with the film thickness, and the 40 μm-thick film exhibited Seebeck coefficient of -66 μV/K, electrical resistivity of 2.4 mΩ-cm, and power factor of 1.75x10^(-4) W/K^(2)-m. Using multilayer overhang process, the photoresist pattern to form thermoelectric legs of 30 μm depth and 100 μm diameter was successfully fabricated.

Antigastritis effects of <i>Armillariella tabescens</i> (Scop.) Sing. and the identification of its anti-inflammatory metabolites

Lee, Seulah,Lee, Dahae,Park, Jun Yeon,Seok, Soonja,Jang, Tae Su,Park, Hyun Bong,Shim, Sang Hee,Kang, Ki Sung,Kim, Ki Hyun Pharmaceutical Society of Great Britain 2018 Journal of pharmacy and pharmacology Vol.70 No.3

생약제제인 이공산(異功散)의 Cisplatin 유도 신장독성 보호 및 항산화 효과

Lee, Kyung-Tae,Ahn, Kyoo-Seok,Chang, Sung-Goo,Oh, Soo-Myung,Jung, Jee-Chang 경희대학교 동서의학연구소 1999 INTERNATIONAL SYMPOSIUM ON EAST-WEST MEDICINE Vol.1999 No.1

Kyung-Tae Lee, Kyoo-Seok Ahn¹, Sung-Goo Chang², Soo-Myung Oh²and Jee-Chang Jung²¹College of Pharmacy, ²Oriental Medicine and ³College of Medicine, and East-West Medical Reserch Institute, Kyung Hee University, Seoul, Korea. Preventive and Antioxidative Effects of Crude Drug Preparation(E-kong-san) on Cisplatin Induced Nephrotoxicity. Proceedings of International Symposium on East-West Medicine, Seoul. 201-211, 1999. -Nephroprotective effects of a crude drug-prearation (E-kong-san) were determined from cisplatin on rabbit kidney proximal tubule and human renal cortical cells by MTT assays and sustained glucose consumption on ciplatin-induced human renal cortical tissue. Levels of creatinine and blood ure nitrogen(BUN) in serum after administration of cisplatin(0.75mg/kg,i.p.) to E-kong-san(0.75g/kg/day,p.o.)-pretreated rats were markedly lower compared to those of cisplatin-treated rats. Moreover, the administration of E-kong-san significantly inhibited the loss of body weight of cisplatin injected rts. These findings suggest that E-kong-san on the cisplatin induced nephrotoxicity led us to investigate whether the effect of this water extract was a result of anti-oxidation. E-kong-san showed strong free radical scavenger activities on 1,1-dipheny1-2picrylhydrazil(DPPH) radical and xanthine/xanthine oxidase(XOD) generated superoxide anion radical(O2-). We further studied the effects of E-kong-san on lipid peroxidation in rat liver microsomes induced by enzymatic and nonenzymatic methods. E-kong-san exhibited significant inhibition on both ascorbic acid/Fe2+and ADP/NADPH/Fe3+ induced lipid peroxidation in rat liver microsomes. Based on these results, we suggest that-E-kong-san attenuate the cisplatin induced cytotoxicity and its mechanism can be eplained by antioxidant.

윤두서(尹斗緖)의 『일본여도』와 다산의 일본 지도론

이상태(Lee, Sang-tae) 연세대학교 강진다산실학연구원 2022 다산과현대 Vol.15 No.-

공재 윤두서는 이만부, 이서, 심득경, 이하곤 등과 교류하면서 그림을 그린 조선 후기 대표적인 근기남인 화가였다. 공재는 중국과 일본의 지리서적과 지도들을 많이 보고 『동국여지지도』와『일본여도』를 제작하였다. 공재가『일본여도』를 제작할 때 이용한 일본지도는『본조도감강목』이다. 이 지도는 일본의 이시카와 류센이 일본지도에 우키요에 화법을 가미하여 일본지도를 아름답게 만든 지도이다. 이 지도는 1711년의 조선통신사 일행이 도입하여 윤두서에게 전해졌고 공재는 이 지도를 보고 『일본여도』를 제작하였다. 『일본여도』는 후에 공재의 외손인 다산 정약용에게 많은 영향을 주었다. 정약용은 지구구형설을 믿었으며 이러한 원리로 지도를 제작하여야만 올바른 지도를 만들 수 있다고 강조하였다. 다산은 『성경전도』 등을 연구하였고 일본의 정세에 대해서도 많은 연구를 하였기 때문에 일본 사정도 잘 알고 있었다. 다산은 공재가 그린 『일본여도』를 보고 매우 감탄하였으며 주변 사람들에게 자랑을 하였다. 그러나 『일본여도』는 일본의 지형과 경위도를 무시하고 아름답게 평면으로 그렸기 때문에 다산이 일본의 경위도를 파악하는데 지장을 주었다. Gongjae Yoon Du-seo was a representative artist of tenacity in the late Joseon Dynasty who painted while interacting with Lee Man-bu, Lee-seo, Shim Deuk-gyeong, and Lee Ha-gon. Gongjae read a lot of geographical books and maps of China and Japan and produced 『Dongguk Yeoji-do』 and 『Japanese Yeo-do』. The Japanese map that Gongjae used to produce 『Japanese Yeo-do』 was 『Bonjo Dogamgangmok』. This map is a map that Ishikawa Ryusen of Japan made the Japanese map beautiful by adding ukiyo-e painting to the Japanese map. This map was introduced by Joseon Tongsinsa in 1711 and handed down to Yun Du-seo, and Gongjae saw this map and produced 『Japanese Yeo-do』. 『Japanese Yeo-do』 later had a great influence on Dasan Jeong Yak-yong, the grandson of Gongjae. Jeong Yak-yong believed in the theory of the sphericity of the earth and emphasized that a correct map can be made only when a map is produced according to this principle. Since Dasan studied 『The Map of Manchuria』 and a lot of research on the situation in Japan, he was well aware of the situation in Japan. Dasan admired Gongjaes 『Japanese Yeo-do』 and boasted to the people around him. However, 『Japanese Yeo-do』 made it difficult for Dasan to grasp the longitude and latitude of Japan because the map was beautifully drawn flat without considering Japans topography and longitude and latitude.

Signed-DLMS 적응 알고리즘 이용한 무선 중계 간섭 제거기

유태훈(Tae-Hoon Yoo),우대호(Dae-Ho Woo),김주완(Dae-Ho Woo),하성희(Sung-Hee Ha),반지훈(Ji-Hun Van),이종현(Jong-Hyun Lee) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.7

In this paper, we study the signed- DLMS adaptive algorithm of wireless repeater for solving shadow region due to propagation between base station and mobile station. The the signed-DLMS algorithm reduces interference signals from multipath and solves the oscillation problem of repeater by estimation and cancellation. To efficiently reject interference signal. the signed-DLMS adaptive algorithm is applied. The computational complexities of the signed-DLMS are reduced verse standard LMS algorithm. Wireless ICS repeater based on signed-DLMS reduces the cost and is able to increase channel capacities.

Effect of Developmental Lead Exposure on the Expression of Hippocampal NMDA Receptor Subunit mRNA

Kim, Tae-Wan,Chung, In-Sung,Bae, Jae-Hoon,Shin, Dong-Hoon,Lee, Mi-Young,Kim, Joon-Sik 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

목적: in vivo 및 vitro에서 해마 신경세포의 발생단계별 NMDA 수용체 아단위 mRNA 발현에 대한 연 폭로 영향을 알아보고자 하였다. 방법: 흰쥐 해마 신경세포의 발생단계별 NMDA 수용체 NR2A, NR2B 아단위 mRNA 발현에 대한 연의 영향은 정상군과 연 폭로군의 출생 후 7일, 14일, 22일 흰쥐의 해마에서 in situ hybridization으로 mRNA 발현 정도를 densitometer로 측정하여 비교하였고, 연과 NMDA 의 세포독성은 해마 신경세포 일차배양 후 도립현미경을 이용한 형태학적인 관찰과 LDH 활성도를 이용하여 측정하였다. 결과: 연 과 NMDA 에 의한 세포독성에 대한 in vitro 실험에서 형태학적 소견과 LDH 활성도에서 해마 미성숙 신경세포와 성숙 신경세포사이의 차이가 있었으므로, 연과 NMDA 독성효과는 해마 신경세포의 발달 단계에 따라 차이가 있다. 정상군의 해마에서의 NR2A mRNA 발현은 출생 후 연령이 증가함에 따라 점진적으로 증가하였으나, NR2B mRNA 발현은 출생 후 연령이 증가함에 따라 점진적으로 증가하였으나 NR2B mRNA 발현은 연령의 증가에 따른 변화가 없었다. 연 폭로에 희한 NR2A mRNA 발현은 유의하게 감소하였으나(p<0.05), NR2B mRNA 발현은 변화가 나타나지 않았다. 만성적 연 폭로는 NR2A를 포함하는 NMDA 수용체를 감소시킬 수 있음을 알 수 있다. 결론: 연은 해마신경세포의 발생단계에서 NMDA 수용체 아단위 특히 NR2A mRNA 발현의 변화를 야기하여 시냅스 신호 전달에 영향을 나타냄을 알 수 있었다. Hippocampus

수답에서 2-(4-(6-chloro-2-benz-oxazolyloxy)phenoxy)-N-phenylpropionamide 유도체 중 N-phenyl 치환체들의 제초활성

성낙도(Nack-Do Sung),이상호(Sang-Ho Lee),고영관(Young-Kwan Ko),이경모(Kyung-Mo Lee),김대황(Dae Whang Kim),김태준(Tae-Joon Kim) 한국농약과학회 2000 농약과학회지 Vol.4 No.2

A new fourty six 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)-N-phenylpro- pionamide derivatives were synthesized and the herbicidal activities against rice plant and barnyard grass with pre-emergence in down land were measured. The structure activity relationships (SAR) between the activities and physicochemical parameters of the substituted(X) N-phenyl group in substrates were analyzed and discussed by Free- Wilson and Hansch method from the basis on the former study (Sung. et. al., 1999). The conditions of selective herbicide activity both the barnyard grass and rice plant are shown that the optimal bydrophobicity, (π)<SUB>opt</SUB>.=1.34 and electron donating with field effect (F<0) of meta and ortho, para-substituted mono or disubstituent on the N-phenyl ring were found to contribute significantly. The herbicidal activities against barnyard grass are roughly the same as the results in up land whereas damage to rice plant in down land more increase than that of up land. Degradation products in water are 2-(4-6-chloro-2-benzoxazolyloxy)phenoxy)propionic acid ((A)) (obs. pKa=4.35 & obs. logP=4.77) and 6-chloro-2-benzoxazolone (B) (obs. pKa=8.40 & obs. logP=2.90). These results were supposing that the hydrolysis product of substrates, (A) is comparatively absorbed in rice plant but not in barnyard grass. And it is assumed from the SAR equations that the 2,6-dimethyl-4-methoxymethyl group substituent (pI??=5.41, 3g/㏊) is selected as the most highest herbicidal acitvity against barngard grass in green house.