• Title/Summary/Keyword: NAS

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Simulation of Optical Characteristics of 1.3 μm GaAs-Based GaAsSb/InGaAs and GaAsSb/InGaNAs Quantum Well Lasers for Optical Communication (광통신용 GaAs 기반 1.3 μm GaAsSb/InGaAs와 GaAsSb/InGaNAs 양자우물 레이저의 광학적특성 시뮬레이션)

  • Park, Seoung-Hwan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.1
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    • pp.1-6
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    • 2011
  • Optical gain characteristics of $1.3{\mu}m$ type-II GaAsSb/InGaNAs/GaAs trilayer quantum well structures were studied using multi-band effective mass theory. The results were compared with those of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structures. In the case of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure, the energy difference between the first two subbands in the valence band is smaller than that of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure. Also, $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure shows larger optical gain than $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure. This means that GaAsSb/InGaNAs/GaAs system is promising as long-wavelength optoelectronic devices for optical communication.

Oil Compositions and Antioxidant Properties of Safflower Germplasm Collected from East Asia (동아시아 잇꽃 유전자원의 지방조성 및 항산화 분석)

  • Sung, Jung Sook;Jeong, Yi Jin;Kim, Da Jeong;Assefa, Awraris Derbie;Jeon, Young Ah;Hur, On Sook;Ro, Na Young;Ko, Ho Cheol;Ok, Hyun Choong;Rhee, Ju Hee;Lee, Myeong Chul;Baek, Hyung Jin
    • Korean Journal of Medicinal Crop Science
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    • v.26 no.1
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    • pp.32-41
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    • 2018
  • Background: To obtain useful safflower resources for breeding and research of functional materials, the present study was conducted to determine fatty acid compositions and antioxidant activities of 281 safflower accessions collected from East Asia including South Korea. Methods and Results: Lipid contents and fatty acids compositions were evaluated using soxhlet extraction and gas chromatography, respectively. A antioxidant activities were analyzed using a spectrophotometer. The evaluation range of safflower accessions showed very wide variation. In terms of lipid contents, the China accessions were higher than the collection from other regions, whereas antioxidant activities did not differ among regions. The result of the principal component analysis showed that the first and second principal component cumulatively explained 90.6% of the total variation. In clustering the safflower accessions, the tree showed four major clades. Group II (16 accessions) was high in lipid content, oleic acid and linoleic acid, whereas group III (50 accessions) exhibited higher antioxidant activities than other groups. Conclusions: It was recommended that the China collections be utilized as a useful resource for research on functional oil materials. These results provided valuable information for safflower breeders and researchers of functional food.

Fates of water and salts in non-aqueous solvents for directional solvent extraction desalination: Effects of chemical structures of the solvents

  • Choi, Ohkyung;Kim, Minsup;Cho, Art E.;Choi, Young Chul;Kim, Gyu Dong;Kim, Dooil;Lee, Jae Woo
    • Membrane and Water Treatment
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    • v.10 no.3
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    • pp.207-212
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    • 2019
  • Non-aqueous solvents (NASs) are generally known to be barely miscible, and reactive with polar compounds, such as water. However, water can interact with some NASs, which can be used as a new means for water recovery from saline water. This study explored the fate of water and salt in NAS, when saline water is mixed with NAS. Three amine solvents were selected as NAS. They had the same molecular formula, but were differentiated by their molecular structures, as follows: 1) NAS 'A' having the hydrophilic group ($NH_2$) at the end of the straight carbon chain, 2) NAS 'B' with symmetrical structure and having the hydrophilic group (NH) at the middle of the straight carbon chain, 3) NAS 'C' having the hydrophilic group ($NH_2$) at the end of the straight carbon chain but possessing a hydrophobic ethyl branch in the middle of the structure. In batch experiments, 0.5 M NaCl water was blended with NASs, and then water and salt content in the NAS were individually measured. Water absorption efficiencies by NAS 'B' and 'C' were 3.8 and 10.7%, respectively. However, salt rejection efficiency was 98.9% and 58.2%, respectively. NAS 'A' exhibited a higher water absorption efficiency of 35.6%, despite a worse salt rejection efficiency of 24.7%. Molecular dynamic (MD) simulation showed the different interactions of water and salts with each NAS. NAS 'A' formed lattice structured clusters, with the hydrophilic group located outside, and captured a large numbers of water molecules, together with salt ions, inside the cluster pockets. NAS 'B' formed a planar-shaped cluster, where only some water molecules, but no salt ions, migrated to the NAS cluster. NAS 'C', with an ethyl group branch, formed a cluster shaped similarly to that of 'B'; however, the boundary surface of the cluster looked higher than that of 'C', due to the branch structure in solvent. The MD simulation was helpful for understanding the experimental results for water absorption and salt rejection, by demonstrating the various interactions between water molecules and the salts, with the different NAS types.

The Method for Data Acquisition on a Live NAS System (활성 상태의 NAS 시스템 상에서 내부 데이터 수집 기법 연구)

  • Seo, Hyeong-Min;Kim, Dohyun;Lee, Sang-Jin
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.25 no.3
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    • pp.585-594
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    • 2015
  • As the storage market has been expanded due to growing data size, the research on various kinds of storages such as cloud, USB, and external HDD(Hard Disk Drive) has been conducted in digital forensic aspects. NAS(Network-Attached Storage) can store the data over one TB(Tera Byte) and it is well used for private storage as well as for enterprise, but there is almost no research on NAS. This paper selects three NAS products that has the highest market share in domestic and foreign market, and suggests the process and method for data acquisition in live NAS System.

Genetic Diversity of Phenotypic Traits and Biochemicals of Lettuce (Lactuca sativa L.) Germplasm

  • On-Sook Hur;Ho-Cheol Ko;Na-Young Ro;Awaris Derbie Assefa;Aejin Hwang;Bichsaem Kim;Seong-Hoon Kim;Youn Jeong Lee;Hee-Jong Woo;Jung-Yoon Yi;Bum-Soo Hahn
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2022.09a
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    • pp.73-73
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    • 2022
  • Lettuce (Lactuca sativa L., Family Asteraceae) is highly ranked in production and economic value and is consumed either fresh or in salad mixes because of its important dietary source of bioactive phytochemicals. The world collection of Lactuca spp. leafy crops, maintained in NAC, includes 2,464 accessions from 71 countries around the world, of which 2,411 belong to L. sativa species, nineteen to L. saligna, and fifteen to L. serriolar. We aimed to investigate the lettuce germplasm with morphological and biochemical analyses and provide new material for breeding. The lettuce crop comprises seven main groups of cultivars (including oilseed lettuce) differing phenotypically. Agricultural characteristcs were investigated including time to bolting, time to flowering, seed color, flower color, leaf attitude, leaf color, leaf anthocyanin coloration, type of incision of margin, depth of incisions of margins, and leaf venation. Screening of the health beneficial metabolites like anthocyanin and bitter sesquiterpene lactones (lactucin and lactucopicrin) was also conducted. The range of anthocyanin and SLs were 0~563.78 mg/100g D.W. and 3.74~3311.66 ug/g D.W., respectively. The investigation of the degree of variation regarding phenotypic traits and biochemical revealed adaptive stable and highly variable use of trait collection.

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