• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.811-813
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• 2008

To see the effect of magnesium on adhesion to natural zeolites, a series of batch tests were performed in this research. Mixed bacteria were sampled from the digestion tank at a local sewage treatment plant in Seoul. Magnesium-zeolites were synthesized by mixing natural zeolites with 0.096 M, 0.24 M, and 0.48 M of MgCl2 solution. For comparison, manganese and trivalent ferric zeolites were also prepared. Two grams of 0.2 mm $\sim$ 0.3 mm sized zeolites(non-treated, Mg, Mn and Fe(III) treated zeolites) and 20 mL of water were mixed in a Corex 25 mL tube. Five milliliters of culture solution including bacteria was added to the tube. The tubes were equilibrated in a shaking incubator at mesophilic temperature $(30{\pm}2^{\circ}C)$. The bacterial concentrations were measured with a Microluminometer (New Horizons 3550i) and total organic carbon (TOC) spectrophotometer (Multi NC-3100).

• 한국주조공학회지
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• 제17권4호
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• pp.379-384
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• 1997

Al-15Cu-lMg alloys have been directionally solidified in 3mm diameter alumina tubes under the conditions of $760^{\circ}C$ of furnace temperature and 12 cm/hr of furnace moving velocity(V). By analyzing the evolution of the temperature profiles along the alloy length, the position of the solid/liquid interface, temperature gradient(G) and local growth velocity (R) were determined. These growth characteristics were compared for 6, 10, 14 cm length alloys. Steady state growth region was obtained in 15 cm length alloy, not in 6, 10 cm.

• 대한조선학회지
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• 제24권2호
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• pp.20-28
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• 1987

In general, preliminary hull form design is performed by changing a parent hull form using a computer to satisfy given requirements, e.g., principal dimensions, displacement, $L_{CB}$, and etc. Principal dimensions, $C_b,\;L_{CB}$ and midship sections are the only parameters to be modified in the traditional hull form variation methods available for preliminary design. In this paper, a method is presented in which local cross sections as well as principal dimensions and midship sections are modified according to design requirements. The method gives hydrostatic curves of modified hull form simultaneously. An optimization technique to satisfy the constraints of hydrostatic characteristics such as maximizing KM as a design requirement is also considered.

• 생물환경조절학회지
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• 제20권2호
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• pp.150-155
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• 2011

캐나다까지 장거리 수출조건은 선적 후 통관까지 20일 동안은 $7{\pm}1^{\circ}C$와 90% 상대습도가 유지되었고, 이후 저장창고 이송전에 3시간만에 $13^{\circ}C$까지 상승한 후 저장창고 이송후 3일간 $3{\sim}4^{\circ}C$와 90% 상대습도를 나타내었다. 이후 상온조건의 판매소에서는 $16^{\circ}C$에 60% 이하의 상대습도를 나타내었다. 이상의 유통조건을 기초로 $7^{\circ}C$, 90% 상대습도에서 15일간 저장한 후 $20^{\circ}C$, 55% 상대습도에서 7일간 저장하는 조건에서 MA저장 실험을 실시하였다. 포장방법에는 무처리와 기존의 유공포장(6mm 직경의 구멍이 $18holes/m^2$) 그리고 레이저로 가공한 3가지 비천공 필름 (산소 투과도 5,000과 20,000 그리고 $100,000cc/m^2{\cdot}day{\cdot}atm$)로 하였다. 저장 중 생체중 감소는 3가지에서는 1% 이하였으나, 유공처리과 무처리는 4% 이상으로 품질 저하가 나타났다. 상온으로 이동한 저장 15일 후 포장재내 대기조성이 $5,000cc/m^2{\cdot}day{\cdot}atm$비천공필름처리는 산소 5%, 이산화탄소 15%를 나타내었고, $20,000cc/m^2{\cdot}day{\cdot}atm$ 비천공필름처리는 산소 16%, 이산화탄소 4~5%를 나타내어, 이들처리에서는 이산화탄소 농도가 파프리카의 적정 범위를 상회하였다. 포장재내 에틸렌 농도는 처리간 큰차이가 없었다. 저장 중 외관상 품질은 이산화탄소 농도가 적절하게 유지되었던 $100,000cc/m^2{\cdot}day{\cdot}atm$ 비천공필름처리에서 가장 높게 유지되었으며, 경도와 당도는 비천공 필름간 차이에 통계적 유의성은 없었다. 이상의 결과로 보아 20일 이상의 장기 유통 중 판매가 상온에서 이루어질 경우 포장내 이산화탄소 농도가 3% 이하로 유지될 수 있는 $100,000cc/m^2{\cdot}day{\cdot}atm$의 통기성을 가장 포장재가 파프리카 MAP에 적합하다고 사료된다.

• 한국연소학회지
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• 제18권1호
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• pp.13-20
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• 2013

Leading edge statistics are obtained by direct numerical simulation(DNS) of freely propagating incompressible and stagnating compressible turbulent premixed flames. Conditional averages of velocities in terms of reaction progress variable, c, and local flame surface density, ${\sum}^{\prime}_f$, are defined and compared through the flame brush. It holds asymptotically that $<u>_f=<S_d>_f$ and $<u>_u-<u>_b=D_t/L_w$ with the characteristic length scale of $\bar{c}$ variation, $L_w$. It also holds that $<u>_b=<u>_f$ for a freely propagating flame under no mean strain rate. The turbulent burning velocity, $S_T$, is determined by the conditional statistics at the leading edge under large activation energy.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 춘계학술대회
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• pp.26-26
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• 2020

Daphne L. (Thymelaceae) comprises about 95 species distributing worldwide from N Africa, N India, SE Asia to E Asia and the coast of the Mediterranean of Europe. In Korea, five species of this genus have been described. In this study, we included four species (D. genkwa, D. pseudomezereum, D. kiusiana, D. jejudoensis) from Korea, excluding cultivated D. odora. The morphological characters through local surveys and the re-classification of the specimens collected in the Korea National Herbarium (KH) were carried out and distribution maps for each taxon were also prepared. The major characters include habit, trichomes in winter bud, leaf, and twig, phyllotaxis, inflorescence, size of calyx lobe and trichomes in the calyx tube, etc. The distribution map showed that D. genkwa is mainly distributed in the coastal area of Hwanghaenam-do, Pyeongannam-do, Jeollabuk-do and Jeollanam-do, whereas D. pseudomezereum is distributed in the limestone zone of Gangwon-do, Jeollabuk-do, and Gyeongsangbuk-do. Similarly, D. kiusiana is mostly found in Jeollanam-do, Gyeongsangnam-do, and Jeju-do. In addition, D. jejudoensis is known to be distributed in forests of Murueng, Andeok, and Seonheul-ri in Jeju-do, but recently, new habitat is discovered in the island forest areas of Jeollanam-do. However, some of these individuals showed the characteristics of D. kiusiana, thus before come to any conclusion detailed taxonomic review of D. jejudoensis and D. kiusiana is required.

• 한국작물학회지
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• 제27권3호
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• pp.261-267
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• 1982

참깨 저온발아성에 대한 품종간 차이를 밝혀 참깨 육종의 기초자료로 삼고저 조, 중, 만생별, 도입국별로 111개 품종을 공시하여 저온 발아온도 범위인 $10^{\circ}C,\;12^{\circ}C,\;14^{\circ}C,\;16^{\circ}C$의 4온도처리로 발아시험을 하였든 바 기 결과를 요약하면 다음과 같다. 1. 저온 범위의 온도별 품종들의 발아율 분포를 보면 $16^{\circ}C$에서는 전품종 평균 발아율 92%였으며 $14^{\circ}C$에서는 57%였으나 $12^{\circ}C$에서는 전공시품종의 30%가 치상후 10일까지도 전혀 발아되지 않아 평균 발아율은 3.3%에 불과했다. 2. 발아세는 온도 $16^{\circ}C$ 처리가 치상후 4일만에 가장 강했으며 $14^{\circ}C$에서는 치상후 8일만에 발아세에 도달하여 4일이나 늦었다. 따라서 70%의 발아(발아전)에 도달하는데 필요한 온도범위는 최소한도 $15^{\circ}C$가 되어야 한다. 3. 참깨 도입원별 저온발아율 차를 보면 한국재래종이 각 온도처리에서 모두 높은 발아율을 보였으며 한국, 일본품종 등 저위도지역산 품종들이 인도나 이집트 등 저위도지역산 품종들보다 높은 발아율을 보였으며 발아세, 평균발아일수, 발아계수 등도 각각 높고 짧았다. 특히 한국재래종인 산동종은 $12^{\circ}C$에서도 24%라는 높은 발아율을 보여 저온발아성이 높은 품종으로 인정되었다. 4. 숙기별 품종간 저온 발아율 차에는 $12^{\circ}C$와 $14^{\circ}C$에서 조생종이 높은 발아력을 나타냈으나 $16^{\circ}C$에서는 조, 중, 만생종 간에 발아력 차이가 없었다. 5. 참깨 종자중과 발아율과의 관계는 단일품종 내에서는 종자중이 무거울수록 발아율이 높았으며 평균 발아일수도 단축되는 경향을 보였으나 공시품종들의 천립중의 경중 특성에 따른 발아력 차이는 없었다.

• 폴리머
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• 제26권3호
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• pp.316-325
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• 2002

비상용성 LDPE/PS 블렌드계 (86.5/l3.5 vol%)를 내부 혼합기를 사용하여 만들었고 레오미터 (rheometer)와 scanning electron microscope (SEM)으로 분산상인 droplet들의 변형과 합체 (coalescence)거동에 대하여 살펴보았다. 혼합 초기에 일정한 크기의 droplet들이 서로 뭉쳐졌고 큰 변형 하에서 실모양 (thread-like)을 나타냈다. 본 실험에 사용한 LDPE/PS 블렌드계의 critical capillary number를 De Bruijn의 실험식으로 계산한 결과 0.96이었고 local capillary number는 3.867이었다. 또한 블렌드 시편을 $200^{\circ}C$에서 다양한 시간으로 서냉한 후 서냉 시간에 따른 형태의 변화를 관찰하였다. $200^{\circ}C$에서 ${\gamma}$=1789일 때 최대 크기의 droplet이 관찰되었고 특히 서냉 시간이 15분일 때 형태의 파괴 (break-up)가 일어났다. Droplet의 합체에 결정적인 영향을 미치는 것은 기질의 점도이다.

• Journal of Positioning, Navigation, and Timing
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• 제5권1호
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• pp.11-20
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• 2016

In this paper, a system that can collect GPS L1 C/A, GLONASS G1, and BDS B1I signals with single front-end receiver was implemented using a universal software radio peripheral (USRP) and its performance was verified. To acquire the global navigation satellite system signals, hardware was configured using USRP, antenna, external low-noise amplifier, and external oscillator. In addition, a value of optimum local oscillator frequency was selected to sample signals from three systems with L1-band with a low sampling rate as much as possible. The comparison result of C/N0 between the signal collection system using the proposed method and commercial receiver using double front-end showed that the proposed system had 0.7 ~ 0.8dB higher than that of commercial receiver for GPS L1 C/A signals and 1 ~ 2 dB lower than that of commercial receiver for GLONASS G1 and BDS B1I. Through the above results, it was verified that signals collected using the three systems with a single USRP had no significant error with that of commercial receiver. In the future, it is expected that the proposed system will be combined with software-defined radio (SDR) and advanced to a receiver that has a re-configuration channel.

• 농업과학연구
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• 제45권4호
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• pp.583-590
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• 2018

Genus Typha L. (Typhaceae; Cattail in common) is one of the hydrophytic plants found in semi-aquatic regions. About nine to 18 species of the genus exist all over the world. In Korea, the most commonly found cattail species are T. laxmanni and T. angustifolia. The aim of this study was to prepare a cDNA library and sequences and analyze expressed sequence tags (ESTs) from these species, T. laxmanni and T. angustifolia. In the case of T. laxmanni, we observed that 715 out of 742 ESTs had high quality sequences, whereas the remaining 27 ESTs were low quality sequences. In this study, we identified 77 contigs, 393 unassembled clones and 65.7% singletons. Furthermore, in the case of T. angustifolia, we recorded 992 high quality EST sequences, and by excluding 28 low quality sequences from among them, we retrieved 120 contigs, 348 unassembled clones and 48.9% singletons. The basic local alignment search tool (BLAST) and Kyoto encyclopedia of genes and genomes (KEGG) database results enabled us to identify the functional categories, i.e., molecular function (16.5%), biological process (22.2%) and cellular components (61.3%). In addition, between these two species, the no hits and anonymous genes were 4.2% and 11.7% and 6.2% and 11.2% in T. laxmanni and T. angustifolia, respectively, based on the BLAST results. The study concluded that they have certain species-specific genes. Hence, the results of this study on these two species could be a valuable resource for further studies.