• Title/Summary/Keyword: cold-active

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Analysis on Heat Dissipation Characteristics of a Tile-Type Digital Transmitter/Receiver Module (적층형 디지털송수신모듈의 방열특성 분석)

  • Yoon, Kichul;Kim, Sangwoon;Heo, Jaehun;Kwak, Nojin;Kim, Chan Hong
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.2
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    • pp.249-254
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    • 2019
  • A Digital Transmitter/Receiver Module(DTRM), which is an essential part in active phased-array radar systems, generates a high heat density, and needs to be properly cooled for stable operation. A tile-type DTRM that is a stacking structure of multi-layer components was modeled with simplification and heat dissipation characteristics of the DTRM model were studied using computational fluid dynamics(CFD) simulations. Most of the heat was dissipated by the heat conduction through the cold plate, but the heat transfer by the forced convection on top of the DTRM also was found to play an important role in the thermal management. Under the given conjugated heat transfer environment, the DTRM was confirmed to secure a stable operating temperature range.

Expression Analysis of the csp-like Genes from Corynebacterium glutamicum Encoding Homologs of the Escherichia coli Major Cold-Shock Protein CspA

  • Kim, Wan-Soo;Park, Soo-Dong;Lee, Seok-Myung;Kim, Youn-Hee;Kim, Pil;Lee, Heung-Shick
    • Journal of Microbiology and Biotechnology
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    • v.17 no.8
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    • pp.1353-1360
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    • 2007
  • Three csp-like genes were identified in the Corynebacterium glutamicum genome and designated cspA, cspB, and cspA2. The genes cspA and cspA2 encode proteins, comprising of 67 amino acid residues, respectively. They share 83% identity with each other. Identity of those proteins with Escherichia coli Csp proteins was near 50%. The cspB gene encodes a protein composed of 127 amino acids, which has 40% and 35% sequence identity with CspA and CspA2, respectively, especially at its N-terminal region. Analysis of the gene expression profiles was done using transcriptional cat fusion, which identified not only active expression of the three genes at the physiological growth temperature of $30^{\circ}C$ but also growth phase-dependent expression with the highest activity at late log phase. The promoters of cspA and cspA2 were more active than that of cspB. The expression of the two genes increased by 30% after a temperature downshift to $15^{\circ}C$, and such stimulation was more evident in the late growth phase. In addition, the cspA gene appeared to show DNA-binding activity in vivo, and the activity increased at lower temperatures. Interestingly, the presence of cspA in multicopy hindered the growth of the host C. glutamicum cells at $20^{\circ}C$, but not at $30^{\circ}C$. Altogether, these data suggest that cspA, cspB, and cspA2 perform functions related to cold shock as well as normal cellular physiology. Moreover, CspA and its ortholog CspA2 may perform additional functions as a transcriptional regulator.

A Novel Esterase from Paenibacillus sp. PBS-2 Is a New Member of the ${\beta}$-Lactamase Belonging to the Family VIII Lipases/Esterases

  • Kim, Young-Ok;Park, In-Suk;Nam, Bo-Hye;Kim, Dong-Gyun;Jee, Young-Ju;Lee, Sang-Jun;An, Cheul-Min
    • Journal of Microbiology and Biotechnology
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    • v.24 no.9
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    • pp.1260-1268
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    • 2014
  • Screening of a gene library from Paenibacillus sp. PBS-2 generated in Escherichia coli led to the identification of a clone with lipolytic activity. Sequence analysis showed an open reading frame encoding a polypeptide of 378 amino acid residues with a predicted molecular mass of 42 kDa. The esterase displayed 69% and 42% identity with the putative ${\beta}$-lactamases from Paenibacillus sp. JDR-2 and Clostridium sp. BNL1100, respectively. The esterase contained a Ser-x-x-Lys motif that is conserved among all ${\beta}$-lactamases found to date. The protein PBS-2 was produced in both soluble and insoluble forms when E. coli cells harboring the gene were cultured at $18^{\circ}C$. The enzyme is a serine protein and was active against p-nitrophenyl esters of $C_2$, $C_4$, $C_8$, and $C_{10}$. The optimum pH and temperature for enzyme activity were pH 9.0 and $30^{\circ}C$, respectively. Relative activity of 55% remained at up to $5^{\circ}C$ with an activation energy of 5.84 kcal/mol, which indicates that the enzyme is cold-adapted. Enzyme activity was inhibited by $Cd^{2+}$, $Cu^{2+}$, and $Hg^{2+}$ ions. As expected for a serine esterase, activity was inhibited by phenylmethylsulfonyl fluoride. The enzyme was remarkably active and stable in the presence of commercial detergents and organic solvents. This cold-adapted esterase has potential as a biocatalyst and detergent additive for use at low temperatures.

Strategies for utilizing Urban Ventilation Corridor considering Local Cold Air in Watershed Areas - A Case Study of Uijeongbu and Gwacheon - (유역의 찬공기 특성을 고려한 도시 바람길 활용 전략 - 경기도 의정부 및 과천 일대를 사례로 -)

  • EUM, Jeong-Hee
    • Journal of the Korean Association of Geographic Information Studies
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    • v.22 no.2
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    • pp.133-151
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    • 2019
  • This study aims to analyze cold air characteristics in the watershed areas and to suggest strategies for utilizing them in urban ventilation corridor plans. For this purpose, the Jungnangcheon watershed and Uijeongbu-si in the northern part of Gyeonggi province, and Anyangcheon watershed as well as Yangjaecheon Tancheon watershed and Gwacheon-si in the southern part were selected as study areas. We used KALM (Kaltluftabflussmodell), a cold air simulation model developed in Germany and identified both the cold air flow and the height of cold air layer generated during 6 hours at night. Uijeongbu City is located on the main stream of the Jungnangcheon watershed, and the local cold air from the southern outskirts is an important part of Uijeongbu-si's overall ventilation corridor planning. In addition, the cold air generated in the vicinity of Mt. Sapae flows into the central business district near the city hall and plays a major role in regulating the thermal environment of the city. But, the cold air flows in the eastern part of Uijeongbu-si was not smoothly. The cold air flow generated in the east of Gwanak Mountain and in the west of Cheonggye Mountain was the most active in the northern part of Gwacheon-si. This flow is also a major ventilation corridor in Anyangcheon watershed as well as Yangjaecheon Tancheon watershed. But, the southern part where the cold air flow is not smooth is planed to be developed as 'Gwacheon Knowledge Information Town Public Housing District', so rapid development is expected in the future. Hence, it is suggested that an additional ventilation corridor plan should be established based on the detailed local wind flow analysis.

Dual Active Clamp Forward(DACF) Inverter for LCD Backlight Drive Applications (LCD Backlight 구동 응용을 위한 고효율 Dual Active Clamp Forward(DACF) Inverter)

  • Shin, Yong-Saeng;Han, Sang-Kyoo;Roh, Chung-Wook;Hong, Sung-Soo;SaKong, Sug-Chin;Kwon, Gi-Hyun;Lee, Hyo-Bum
    • Proceedings of the KIPE Conference
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    • 2007.07a
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    • pp.268-270
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    • 2007
  • LCD Backlight 구동 응용을 위한 새로운 인버터 회로 Topology인 Dual Active Clamp Forward (ACF) Inverter를 제안한다. 제안된 회로는 LCD의 광원 역할을 하는 냉음극 형광램프(Cold Cathode Fluorescent Lamp, CCFL) 구동을 위한 회로로서, 넓은 입력 범위 및 부하 범위에서도 영 전압 스위칭 동작을 보장하며, 출력 AC 전류의 대칭성을 보장한다. 더욱이 기존 Symmetric Phase Shift Full Bridge방식은 특허 우선순위가 있는 방법으로써, Dual ACF Inverter를 사용할 경우 특허 Royalty 부담을 줄일 수 있다. 본 논문에서는 제안된 회로의 동작원리에 대한 타당성을 이론적 분석 및 모의실험을 통하여 검증한다.

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Crystal Structure and Functional Characterization of a Xylose Isomerase (PbXI) from the Psychrophilic Soil Microorganism, Paenibacillus sp.

  • Park, Sun-Ha;Kwon, Sunghark;Lee, Chang Woo;Kim, Chang Min;Jeong, Chang Sook;Kim, Kyung-Jin;Hong, Jong Wook;Kim, Hak Jun;Park, Hyun Ho;Lee, Jun Hyuck
    • Journal of Microbiology and Biotechnology
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    • v.29 no.2
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    • pp.244-255
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    • 2019
  • Xylose isomerase (XI; E.C. 5.3.1.5) catalyzes the isomerization of xylose to xylulose, which can be used to produce bioethanol through fermentation. Therefore, XI has recently gained attention as a key catalyst in the bioenergy industry. Here, we identified, purified, and characterized a XI (PbXI) from the psychrophilic soil microorganism, Paenibacillus sp. R4. Surprisingly, activity assay results showed that PbXI is not a cold-active enzyme, but displays optimal activity at $60^{\circ}C$. We solved the crystal structure of PbXI at $1.94-{\AA}$ resolution to investigate the origin of its thermostability. The PbXI structure shows a $({\beta}/{\alpha})_8$-barrel fold with tight tetrameric interactions and it has three divalent metal ions (CaI, CaII, and CaIII). Two metal ions (CaI and CaII) located in the active site are known to be involved in the enzymatic reaction. The third metal ion (CaIII), located near the ${\beta}4-{\alpha}6$ loop region, was newly identified and is thought to be important for the stability of PbXI. Compared with previously determined thermostable and mesophilic XI structures, the ${\beta}1-{\alpha}2$ loop structures near the substrate binding pocket of PbXI were remarkably different. Site-directed mutagenesis studies suggested that the flexible ${\beta}1-{\alpha}2$ loop region is essential for PbXI activity. Our findings provide valuable insights that can be applied in protein engineering to generate low-temperature purpose-specific XI enzymes.

Analysis of Tendency and Characteristics in Armed Conflict in Post-Cold War Era: on the basis of UCDP (탈냉전 후 무력갈등의 추세와 특징에 관한 분석: UCDP 자료를 중심으로)

  • LEE, CHULKI
    • International Area Studies Review
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    • v.18 no.3
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    • pp.269-291
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    • 2014
  • The purpose of this article is to analyze the tendency and characteristics in armed conflict in post-Cold War era on the basis of Uppsala conflict data program(UCDP) datasets. The collapse of bipolarity and the end of cold War proved a watershed in the dynamics of international conflict. The major shift in the nature of conflict has been away from interstate conflict, leaving intrastate conflict. Major powers have acted carefully against each other and been willing to understand the interests of other to avoid military confrontation and crash. As the means of termination for armed conflict, there is a stronger emphasis on the peace settlement like peace agreement and ceasefire agreement than military victory. Many intrastate conflicts become internationalized, through the involvement of diaspora communities, or regionalized through a spillover effect into neighboring countries. Since the end of the Cold War, the UN has taken a much more active role in conflict management and conflict resolution.

The Physiological and Ecological Comparisons between Warm (Pleuromamma sp.) and Cold Water Copepod Species (Neocalanus plumchrus) in the Northwestern Pacific Ocean Using Lipid Contents and Compositions (북서태평양에서 난수성(Pleuromamma sp.)과 냉수성(Neocalanus plumchrus) 요각류의 지방 함량 및 구성 분석을 통한 생리/생태 비교)

  • Ko, Ah-Ra;Ju, Se-Jong;Lee, Chang-Rae
    • Ocean and Polar Research
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    • v.31 no.1
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    • pp.121-131
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    • 2009
  • In an effort to better understand the physiological and ecological differences between warm and cold water copepod species in Korean waters using lipid contents and compositions, two species of copepods (Pleuromamma sp. as a warm water species and Neocalanus plumchrus as a cold water species) were collected from the Northwest Pacific and East Sea/Sea of Japan, respectively. The cold water species showed two fold higher lipid contents than the warm water species (11% vs. 5% of dry weight). Wax esters, known as one of the major storage lipid classes, were found to be the dominant lipid class (accounting for 64% of total lipids) in the cold water species, whereas, in the warm water species, phospholipids, which are known as membrane components, were the dominant lipid class (accounting for 43% of total lipids),with a trace amount of the storage lipids as a form of triacylglycerols (${\leq}1%$ of total lipids). With regard to the fatty acid compositions, saturated fatty acids (SAFA), especially 16:0 (about 30% of total fatty acids), were most abundant in the warm water species, whereas the polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic acid (EPA : 20:5(n-3)) (${\geq}16%$ of total fatty acids), were most abundant in the cold water species. Among the neutral fraction of lipids, phytol, originating from the side chain of chlorophyll and indicative of active feeding on phytoplankton, was detected only in the warm water species. Significant quantities of fatty alcohols were detected in cold water species, particularly long-chain monounsaturated fatty alcohols (i.e. 20:1(n-9) and 22:1(n-11)), which are well known to abound in cold water herbivorous copepods. However, only trace amounts of short-chain fatty alcohols were detected in the warm water species. Twelve different kinds of sterols were detected in these copepod species, with cholest-5-en-$3{\beta}$-ol (cholesterol) and cholesta-5, 24-dien-$3{\beta}$-ol (desmosterol) dominating in cold and warm water species, respectively. In addition, for the warm water species (Pleuromamma sp.), we assessed the latitudinal gradients of lipid contents and compositions using samples from three different latitudinal regions (Philippine EEZ, Japan EEZ, and the East China Sea). Although no latitudinal gradients of lipid contents were detected, the lipid compositions, particularly dietary fatty acid markers, varied significantly with the latitude. The findings of this study confirm that the distribution of lipid contents and compositions in copepods may not only indicate their nutritional condition and diet history, but may also provide insights into their living strategies under different environmental conditions (i.e., water temperature, food availability).

A Study on the Clothing Image Perception of Elderly Women According to Sex-Role Attitude and Gender

  • Lee, Myoung-Hee;You, Kyung-Sook;Lee, Eun-Sil
    • International Journal of Costume and Fashion
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    • v.3
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    • pp.107-120
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    • 2003
  • The purpose of this study was to examine the differences in the clothing image perception of elderly women according to the clothing types, the clothing colors, the perceiver's sex-role attitude, and gender. Result of factor analysis revealed that the dimensions of clothing image perception was classified into four categories: evaluation, youth, warmth, and activity. Perceiver's sex-role attitude and gender gave a significant influence on the perception of evaluation factor. Youth factor had an interaction effect on the clothing types, clothing colors, and sex-role attitudes. The persons with a conservative sex-role attitude perceived the clothing image of warm color suits as younger than the one of cold colors. The clothing image of a warm colored Hanbok (Korean traditional dress) was perceived milder than a cold one, but there were no difference in suits. Bright color suits make the wearer look younger, and cold color suits make the wearer look active. The clothing color had greater influences on the warmth and the evaluation factor than clothing types. Persons who have a conservative sex-role attitude perceived the differences according to clothing types and colors in a traditional way. It could be certified that perceiver's sex-role attitude was one of the variables influencing his/her perception in social interaction.

Performance assessment of apparatus for controlling algae bloom in aqua pet pank using by a cold plasma (관상어 수족관용 저온 플라즈마방식 녹조억제장치의 성능 평가)

  • Lee, Kyounghoon;Jang, Kyu-Sup;Kim, Seonghun;Park, Seong-Wook
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.49 no.2
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    • pp.126-135
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    • 2013
  • This study was performed to have an effect on control the growth of algae such as "Actinastrum fluviatile" which occurs frequently in the aquaculture tank using by a cold plasma, and it also would be expected to promote the growth of water plants due to active element causing OH radicals in the water. In addition, it was verified on the death rate as 99.9% on the scale protrusion of "Aeromonas hydrophila" as well as E. coli, especially, under extreme conditions more than 100 million pathogenic bacterium in the aqua pet tank, the ornamental fish had to act in a safe and healthy environment at over 98% death rate within 48 hours. It has been proven to give no affect on aerobic bacteria that exist in the filter or soil because there was no residual toxicity in the water tank. As the results, it will help to develop and apply on the sterilization device in other industries as well as aquarium organisms due to adopted energy-saving algorithm and reliability in use.