Effects of Neodymium and Calcium on the Thermal Stability of AZ71 Magnesium Alloys

Cheng‑Feng Yue,Shi‑Jei Huang,Jhewn‑Kuang Chen,Hsien‑Tsung Li,Kam‑Shau Chan 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.2

The effects of an addition of 0–2 wt% Nd on thermal stability of 0–3 wt% Ca-containing modified AZ71 magnesium alloyswas investigated. The ignition temperature was found to increase from that of AZ71, 574, to 825 °C with the addition of0.5 wt% Ca and 1 wt% Nd. The ignition temperature was further increased to 1114 °C when 3 wt% Ca was added. The CaandNd-added AZ71 was isothermally maintained at a temperature of 500 °C in air for 12 h. The MgO–CaO–Nd2O3 formedon the surface to improve the thermal stability of the AZ71–xCa–yNd alloys. While both the tensile strength and ductilitydecreased with the Ca concentration in the alloy, an addition of 1 wt% Nd was found able to alleviate the degradation effectsof Ca on the tensile strength and ductility at 170 °C. Both solid solution formation and precipitation strengthening contributedto the increase in toughness. AZ71 containing 0.5–2 wt% Ca and 1 wt% Nd provides the optimum combination of ignitionresistance and mechanical properties.

발효콩 추출물의 항돌연변이원성 및 세포독성 효과

최승필,이효진,문선영,김수현,이득식,함승시 동아시아식생활학회 2004 동아시아식생활학회지 Vol.14 No.3

This study was carried out to determine the antimutagenic and anticancer effects of fermented soybean using Ames test and cytotoxicity, respectively. The ethyl acetate fraction (200 g/plate) of fermented soybean in the Salmonella typhimurium TA100 strain showed 86.6% of inhibition rate against the mutagenesis induced by N-methyl-N-nitro-N-nitrosoguanidine(MNNG). In addition, the suppression of ethyl acetate fraction with same concentration of fermented soybean in the Salmonella typhimurium TA98 and TA100 strains showed 82.4% and 90.8% inhibition against 3-amino-1,4-dimethyl-5H-pyrido-(4,3-b)indol (Trp-P-1), respectively. The cytotoxicity effects of fermented soybean against the cell lines with human lung carcinoma (A549), human gastric carcinoma (AGS) and human breast adenocarcinoma (MCF-7) were inhibited with the increase of the extract concentration. The treatment of 1.0 ㎎/mL ethyl acetate fraction of fermented soybean showed strong cytotoxicities of 71.6%, 91.5% and 80.7% against A549, AGS and MCF-7, respectively.

다시마 분말을 첨가한 막장 에탄올 추출물의 항돌연변이원성 및 세포독성 효과

최승필,조미애,전윤영,이득식,함승시 동아시아식생활학회 2002 동아시아식생활학회지 Vol.12 No.1

This study was carried out to investigate antimutagenic and cytotoxic effects of Korean traditional Mackjang added with sea tangle powder. The content percentage of most of minerals among general composition increased by adding sea tangle powder. By the Ames test, the antimutagenic effect of ethanol extract of Korean traditional Mackjang added with 5% sea tangle powder was strongest, exceeding the control, 10% and 15% sea tangle additions. The ethanol extract (400 ㎍/plate) of Mackjang added with 5% sea tangle powder in the S. typhimurium TA100 strain showed inhibition rate of 95.0% against the mutagencsis induced by MNNG. The inhibition rate of ethanol extract (400 ㎍/plate) of Mackjang added with 5% sea tangle powder in the S. typhimurium TA98 and TA100 strains was 81.4% and 88,8%, respectively, against the mutagencsis induced by 4NQO. Cinder the same conditions, the suppression against B(a)P and Trp-P-1 in the TA98 and TA100 strains were 85.3% and 91.0%, and 96.5% and 92.0%. respectively. For the anticancer effects, an investigation was done on the cytotoxicity of Mackjang added with 5% sea tangle powder on the cell lines with human lung carcinoma (A549), human hepatoeellular carcinoma (HepG2), and human gastric carcinoma (KATOIII). The cytotoxicities were inhibited with increasing the extract concentration. The treatment of 1.0 ㎎/mL Mackjang added with 5% sea tangle powder showed relatively strong cytotoxicity of 61.2%, 61.8% and 66.8% against A549, KATOIII, and HepG2, respectively.

가시오갈피 열매 추출물의 항돌연변이원성 및 세포독성 효과

전윤영,최승필,이효진,문선영,이득식,함승시 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2003 한국식품저장유통학회지 Vol.10 No.3

가시오갈피(Eleutherococcus senticous Maxim) 열매의 에탄올 추출물 및 분획물의 항돌연변이성 및 항암활성을 규명하였다. 항돌연별이원성 실험결과에서는 직접변이원인 MNNG, 4NQO 그리고 간접변이원인 B(α)P, Trp=P-1에 대해서 농도의존적인 돌연변이 억제활성을 나타내었다. MNNG (0.4㎍/plate)의 경우 S. typhimurium TA100 균주에서는 시료농도 200㎍/plate에서 클로로포름 분획물을 제외한 모든 분획물들에서 90%이상의 높은 억제효과를 나타내었다. 4NQO(0.15㎍/plate)에 대한 S. typhimurium TA98 균주의 경우 물 분획물의 경우 88.3%, TA100 균주에서는 에틸 아세테이트 분획물이 84.4%의 억제효과를 보였다. 간접변이원의 경우 B(α)P(10㎍/plate)에선느 에탄올 추출물과 핵산 분획물은 시료농도 200㎍/plate에서 각각 96.1%와 97.5%로 가장 높은 억제효과를 나타내었다. 그리고 Trp-P-1(0.15㎍/plate)에서는 TA100 균주의 경우 200㎍/plate 농도에서 에탄올 추출물과 물 분획물이 각각 95.5%와 90%로 높은 억제율을 보여주었고, TA98 균주에 대해서는 에틸아세티에트 분획물이 88.3%로 비교적 높은 억제효과를 나타내었다. 인간의 암세포인 폐암세포(A549), 위암세포(AGS), 간암세포(Hep3B), 유방암세포(MCF-7)에 대한 세포독성 억제 효과를 검토한 결과 모든 암세포에서 각분획물들은 1㎎/mL 농도에서 60% 이상의 비교적 높은 암세포 성장 효과를 나타내었다. 특히 MCF-7에서 높은 암세포 성장억제 효과를 나타내었는데 핵산 분획물(1㎎/mL)에서 92.7%의 높은 암세포 성장 억제 효과를 나타내었고 Hep3B에서는 부탄을 분획물(1㎎/mL)에서 82%의 비교적 높은 성장 억제효과를 나타내었다. This study was carried out to investigate the antimutagenic and cytotoxic effects of Eleutherococcus senticosus Maxim fruits ethanol extract on Salmonella typhimurium TA98, TA 100 and cancer cell lines using Ames test and SRB assay, respectively. They were extracted with ethanol and then fractionated with hexane, chloroform, ethyl acetate, butanol and water to get active fractions. In the Ames test, most of the extract had strong antimutagenic effects against the mutagenesis induced by MNNG, 4NQO, B(α)P Trp-P-1. The ethanol extract (200 ㎍/plate) of Eleutherococcus senticosus fruits showed 87.2% inhibitory effect on the mutagenesis induced by MNNG against TA100. And also, The suppression ratio against B(α)P and AGS, MCF-7, Hep3B), the value value of inhibition were mostly above 60% for each fraction (1 ㎎/mL). Hexane fraction (1 ㎎/mL) against showed the strongest cytotoxic effects of 92.7% compared to those of other fraction and butano fraetion against Hep3B was relatively high growth inhibitory effect of 82%.

한국산 생열귀나무 (Rosa davurica Pall.) 잎의 성분 및 항산화 효과에 관한 연구

김준범,최승필,이득식,함승시 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2004 한국식품저장유통학회지 Vol.11 No.1

생열귀나무의 잎에 대한 일반성분과 tocopherol 동족체를 분석하였으며, 생리활성 기능을 검색하기 위해 메탄올 추출물의 항산화력을 보다 더 정제하기 위해 헥산, 클로르포름, 에틸아세테이트, 부탄올 및 물충으로 분획하여 얻어진 추출물과 분획물을 이용하여 자외선(UV 308, 350 nm) 차단효과와 DPPH 자유라디칼 소거법에 의한 항산화성 효과를 검토하여 다음과 같은 결론을 얻었다. 일반성분의 분석 결과 수분이 67.5%로 가장 높게 나타났으며, 탄수화물 18.9%, 조단백질 6.8%, 회분 6.1% 그리고 조지방 0.7% 순이었다. 무기질 함량으로 가장 높은 것은 칼륨으로 1,637.2 mg%로 나타났다. 메탄올 추출물을 물로 현탁시킨 후 헥산, 클로르포름, 에틸아세테이트, 부탄올 순서로 용매를 분획하여 각각의 분획물을 얻은 결과 물(34.8%)이 가장 높게 분획되었으며, 메탄올 추출물을 각각 n-헥산, 클로르포름, 에틸아세테이트, n-부탄올 및 물 분획물을 얻어 자외선 차단효과를 측정한 결과 장파장대 (UVA 320∼400 nm)의 경우 에틸아세테이트 분획물(151.4)에서 가장 높게 측정되었다. 한편, 메탄올 분획물의 항산화 활성을 검토한 결과 에틸아세테이트 분획물의 항산화 홀성 (IC_(50) : 6.0 μg)이 가장 높았으며, 그 다음이 부탄올 분획물((IC_(50) : 14.0 μg)로 나타났다. The objective of this study was carried out to investigate nutritional characteristics and biological activities effects of Korean leaf of Rosa davurica Pall, in vitro. They were extracted with methanol and then further fractionated to n-hexane, chloroform, ethyl-acetate, n-butanol and water from methanol extracts. Methods of the antigenotoxic used in this experiment were UVA/UVB absorption property and DPPH radical scavenge. The proximate compositions of leaves of Rosa dauvrica Pall were 67.5% of crude Moisture, 0.7% of crude fat, 6.8% of crude protein, 6.1% of crude ash, and 20.8% of crude fiber. The major minerals were K (1637.2 mg%), Ca (219.5 mg%), and Mg(135.1 mg%). Most of the fractions of methanol extract which leaves of Rosa dauvrica Pall, have strong absorbency at UVB region (308 nm) and UVA region (350 nm). These fractions have a good absorbency property as synthetic filter and could be served as substitutes for synthetic UV sunscreen agents. All fractions (n-hexane, ethyl-acetate, n-butanol and water) from methanol extracts except chloroform fraction exhibited DPPH radical scavenging activity with IC_(50) of 35.3, 6.0, 14.0, and 18.0 μg/mL.

한국산 생열귀나무 (Rosa davurica Pall.) 잎의 생리활성 기능 검색에 관한 연구

김준범,최승필,이득식,함승시 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2004 한국식품저장유통학회지 Vol.11 No.1

생열귀나무의 잎을 시료로 생리활성 기능을 검색하기 위해 메탄올, 에탄올, 클로르포름 및 물 추출물을 조제 하였다. 얻어진 추출물에 대하여 DPPH 자유라디칼 소거법에 의한 항산화성 효과와 S. thphimurium TA98과 TA100을 이용한 항돌연변이원성 효과를 검토하여 다음과 같은 결론을 얻었다. 생열귀나무 잎의 용매별 추출수율은 물 추출물이 24.8%로 가장 높았으며, 그 다음으로는 메탄올 추출물 (21.3%), 에탄올 추출물 (17.0%) 및 클로로포름 추출물 (5.6%) 순으로 높은 수율을 나타내었다. 생열귀나무 잎의 각 추출물의 수소전자공여능 IC_(50)(Inhibition comcentration)을 측정한 결과 물, 메탄올, 에탄올 추출물의 경우 대조구인 butyl-hydroxytoluence, 비타민 C, 알파토코페놀과 유사하게 나타나 항산화 억제효과가 우수한 것으로 나타났다. 생열귀나무 잎의 메탄올 추출물의 항돌연변이 효과는 TA98 균주에 대하여 세 종류의 변이원 물질 모두 농도 증가에 따라 억제율이 증가함을 나타내었으며, 생열귀나무 잎의 클로르포름 추출물 결과는 TA98균주에 대하여 3가지 변이원 물질 모두 농도 증가에 따라 억제율이 증가함을 나타내었다. 생열귀나무 잎의 에탄올 추출물의 경우 TA98 균주에 대하여 200 μg/plate의 농도를 첨가하였을 때 B(α)P에 대해 79.8%의 억제율로 가장 높은 수치를 나타내었고, 생열귀나무 잎의 물 추출물은 TA98 균주에 대하여 200 μg/plate의 농도 첨가에서 B(α)P에 대해 67.2%의 억제율을 보였다. The objective of this study was carried out to investigate biological activities effects of Korean leaf from Rosa davurica Pall, in vitro. They were extracted with methanol, ethanol, chloroform and water. Methods of the antimutagenic used in this experiment were well-known bacterial short term tests which include Ames test and the antigenotoxic used in this experiment was DPPH radical scavenge. All extracts (ethanol, methanol, water) except chloroform extract exhibited 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity with IC_(50) of 11.5 μg/mL, 6.4 μg/mL, 4.8 μg/mL. In Ames test, most of extracts had strong antimutagenic effects against the mutagenesis induced by 4-nitroquinoline-1-oxide (4NQO), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 3-amino-1, 4-dimethyl-5H-pyrido[4,3-b]indol(Trp-P-1) and benzo(α)pyrene(b(α)P). The extracts of leaves (200 μg/plate) showed approximately 60~80% inhibitory effect on the mutagenesis induced by 4NQO, Trp-P-1 and B(α)P against TA98 strain, whereas 60~80% inhibition were observed on the mutagenesis induced by MNNG, 4NQO, Trp-P-1 and B(α)P against TA100 strain, respectively.

Spectrum Allocation in Cognitive Radio Using Game Theory

Cheng Shi Zhao,Ming Rui Zou,Bin Shen,Ho Hwan Park,Kyung Sup Kwak 한국통신학회 2008 한국통신학회 학술대회 및 강연회 Vol.2008 No.4

Performance evaluation of soil-embedded plastic optical fiber sensors for geotechnical monitoring

Cheng-Cheng Zhang,Hong-Hu Zhu,Bin Shi,Jun-Kuan She,Dan Zhang 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.17 No.2

Based on the distributed fiber optic sensing (DFOS) technique, plastic optical fibers (POFs) are attractive candidates to measure deformations of geotechnical structures because they can withstand large strains before rupture. Understanding the mechanical interaction between an embedded POF and the surrounding soil or rock is a necessary step towards establishing an effective POF-based sensing system for geotechnical monitoring. This paper describes a first attempt to evaluate the feasibility of POF-based soil deformation monitoring considering the POF–soil interfacial properties. A series of pullout tests were performed under various confining pressures (CPs) on a jacketed polymethyl methacrylate (PMMA) POF embedded in soil specimens. The test results were interpreted using a fiber–soil interaction model, and were compared with previous test data of silica optical fibers (SOFs). The results showed that the range of CP in this study did not induce plastic deformation of the POF; therefore, the POF–soil and the SOF–soil interfaces had similar behavior. CP was found to play an important role in controlling the fiber–soil interfacial bond and the fiber measurement range. Moreover, an expression was formulated to determine whether a POF would undergo plastic deformation when measuring soil deformation. The plasticity of POF may influence the reliability of measurements, especially for monitored geo-structures whose deformation would alternately increase and decrease. Taken together, these results indicate that in terms of the interfacial parameters studied here the POF is feasible for monitoring soil deformation as long as the plastic deformation issue is carefully addressed.

Network Structure Analysis of a Sub-Hub-Oriented Port

Shi-cheng Song,Sung Hoon PARK,Gi-tae YEO 한국해운물류학회 2019 The Asian journal of shipping and Logistics Vol.35 No.2

The Port of Gwangyang was built with the aim of reducing congestion at the Port of Busan by acting as sub-hub port. Many studies have discussed the new port construction and dual-hub port system to solve the increasing demand and port congestion problems; however, there is not much research discussing the sub-hub port system. As such, the main purpose of this paper is to analyze the liner shipping network structure of the sub-hub-oriented Port of Gwangyang using social network analysis (SNA). In terms of number of connections among ports, using in-degree, outdegree, and betweenness centrality, Busan is the most important port in Gwangyang’s network. However, when it comes to considering the influence of ports using hub centrality, Busan drops to the fifth most influential position. In the network of the Port of Gwangyang, Shanghai and Hong Kong have more important roles compared to those of the Port of Busan.

Mechanical Property Test and Analytical Method for Reactive Powder Concrete Columns under Eccentric Compression

Cheng-hua Shi,Min Long,Cheng-yong Cao,Guangcheng Long,Ming-feng Lei 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.4

Reactive Powder Concrete (RPC) has ultra-high strength, toughness and durability. Review studies were focused on the mechanical properties of RPC material and RPC beam. In this paper, the bearing features of RPC columns under eccentric compression with different section dimensions, reinforcement ratios, and conditions of with and without steel fibres were determined through large eccentric compression test of 22 RPC columns. The distribution patterns of stresses over the section of the RPC columns under large eccentric compression were determined under cracking loads. A simple analytical method for the cracking loads was also established. Test results revealed that the thickness ratio of elastic tensile region and the whole tensile region can be 0.4 (with steel fibres) or 0.5 (without steel fibres) when calculating the cracking loads. The tensile stress on the RPC columns showed an isosceles triangle distribution in the tensile region. A simple analytical method for calculating the ultimate loads of RPC columns under large eccentric compression was set up. Test results revealed that the equivalence coefficient of the RPC column in tensile regions can be 0.6 (with steel fibres) or 0.4 (without steel fibres). The method deduced in this paper can be used to design the RPC column under large eccentric compression.