• Korean Journal of Weed Science
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• v.30 no.4
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• pp.445-453
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• 2010

This study was conducted to investigate herbicidal efficacy and diffusibility of halosulfuron-methyl+mefenacet in water treated with 500 g great granule (GG) and 3 kg granule (GR). The 500 g GG was been spreading on the surface of the water within 6 minutes, 53 seconds, and it's active ingredient was diffused in the water bath of $10m^2$ size between 30 and 60 minutes. In addition, the diffusion of 500 g GG was influenced by moisture contents, so it have to immediately use 500 g GG in paddy fields when it was been unpacked. The herbicidal efficacy of the 500 g GG and 3 kg GR of halosulfuron-methyl+mefenacet was excellent to most weed species, but showed different efficacy for the control of Aneilema keisak and Scirpus juncoides, that was may be distribution pattern of active ingredient as different formulation.

• Korean Journal of Plant Resources
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• v.35 no.1
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• pp.71-99
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• 2022

This study was conducted to investigate the vascular flora of Masan, located in Goseong-gun, Gangwon-do, and to comprehend the distribution of remarkable plants such as rare and Korea endemic plants and invasive alien plants. The survey was carried out the distribution of vascular plants 11 times per season from 2010 to 2018. A total of 619 taxa in 93 families, 328 genera, 529 species, 6 subspecies, 78 varieties and 6 forms were identified on mt. Masan. Among them, Korean endemic plants are 21 taxa including Saussurea diamantica Nakai and are plants designated by the Korea Forest Service are 20 taxa counting Saxifraga octopetala Nakai. Invasive alien plants were classified a total of 35 taxa inclusive of Trifolium pratense L. (WS), Aster pilosus Willd. (SS), Coreopsis lanceolata L. (SR), Rumex obtusifolius L. (SC) and Lindernia dubia (L.) Pennell (CS). The naturalization rate was 5% and the urbanization index was 10.0%, respectively. Although this study identified the diverse distribution of major plants such as rare and endemic plants around Masan, it was confirmed that invasive alien plants, which pose a great threat to forest biodiversity conservation and promotion, spread and distributed in a specific section Therefore, it is urgent to establish a conservation strategy and countermeasures.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.7
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• pp.591-598
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• 2015

Pool boiling heat transfer coefficients of a LiBr solution were obtained for seven low fin tubes having different fin pitch and fin height. The test range covered saturation pressure from 7.38kPa to 101.3kPa, heat flux from $20kW/m^2$ to $40 kW/m^2$ and LiBr concentration from 0% to 50%. The optimum fin geometry for the present experimental range turned out to be 26 fpi with 0.18 mm fin height.The advantage of added heat transfer area and the disadvantage of slower bubble growth and departure appear to have yielded an optimum fin pitch. The heat transfer coefficient decreased as saturation pressure decreased and Libr concentration increased. The reason may be attributed to the low saturation pressure, which increased the bubble departure diameter and decreased the bubble departure frequency. As the LiBr concenreation increased, the saturation temperature increased and the mass diffusion rate decreased, which resulted in a reduced heat transfer coefficient. The heat transfer coefficients of the low fin tube were greater than those of the smooth tube. Correlations were developed based on the present data.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.396-404
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• 2010

Phenolic compounds, which are products of secondary metabolism, have been demonstrated to be widespread growth substances in plants. The objectives of this study were to identify the phenolic compounds in common ragweed (Ambrosia artemisiifolia var. elatior) by HPLC and to evaluate their effects on germination and seedling growth of three weed species. Under controlled conditions in Petri dishes at $25^{\circ}C$, $10^{-3}$ and $10^{-4}$ M solutions of phenolic compounds were evaluated in seed germination tests. Four phenolic compounds (caffeic acid, O-coumaric acid, ${\rho}$-coumaric acid and ferulic acid) in common ragweed plant were identified and their concentration was increased from the stage before flowering through full flowering stage. Treatment of O- and ${\rho}$-coumaric acids delayed the seed germination of Digitalia ciliaris, while the treatment of caffeic acid delayed the seed germination of Echinochloa crus-galli. In time to 50% germination ($T_{50}$), phenolic compounds at $10^{-4}$ M promoted in Cyperus microiria and E. crus-galli but the level of $10^{-3}$ M delayed the $T_{50}$ of those weeds. The O-coumaric acid inhibited seed germination and seedling growth of the tested weeds and especially it perfectly inhibited the root growth of E. crus-galli.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.39 no.1
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• pp.20-30
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• 2021

The purpose of this study was to identify the ecological characteristics of Namhan Mountain Fortress Walls vascular plants through investigation and analysis of Namhan Mountain Fortress Walls and to provide basic data when establishing a plan for conservation and management of Namhansanseong Fortress Wall vascular plants. The result of this survey revealed 249 taxa composed of 77 families, 169 genera, 222 species, 5 subspecies, 19 varieties and 3 forms. In terms of life form of Namhan Mountain Fortress Walls, the appearance rate of Hemicryptophytes(H) was high. Rare plants was 1 taxa and Korea endemic plants was 5 taxa. The total number of floristic regional indicator plants was 15 taxa, gradeI 9 taxa, gradeII 2 taxa, gradeIII 3 taxa, gradeIV 1 taxa. Among them, Polygala tatarinowii Regel is considered to the most important(gradeIV), and it is first description because in Gyeonggi-do, as no additional forms have been confirmed other than this site. Plants identified as rock vegetation were found in 21 taxa. Invasive alien plants were identified 20 taxa. Plants distributed on the walls of Namhan Mountain Fortress, such as Aconitum longecassidatum Nakai, Clematis heracleifolia DC. var. tubulosa (Turcz.) Kuntze, Hylotelephium spectabile (Boreau) H.Ohba and Polygala tatarinowii Regel etc, are feared to decrease the number of species and individuals due to the loss of walls, the spread of invasive alien plant and human interference, so conservation and management measures are needed.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.294-299
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• 2008

The present study investigates the ventilation effects on smoke spreading with the rescue stations. Experiments for tunnel fires were carried out for n-heptane pool em at different fire locations, and the heat release rates (HRR) were obtained by addition, using the commercial code (FLUENT), the present article presents numerical results for smoke behavior in railway tunnels with rescue station, and it uses the MVHS (Modified Volumetric Heat Source) model for estimation of combustion products resulting from the fire source determined from the HRR measurement. As a result, it is found that smoke propagation is prevented successfully by the fire doors located inside the cross-passages and especially, the smoke behavior in the accident tunnel can be controlled through the ventilation system because of substantial change in smoke flow direction in the cross-passages.

• 한국벤처창업학회:학술대회논문집
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• 2017.08a
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• pp.69-89
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• 2017

본 연구의 목적은 우리나라 대학의 도전적 창업문화 정착, 대학생의 창업역량 강화로 글로벌 경쟁력을 갖춘 창업 확대에 필요한 창업교육 방안을 제시하는 것이다. 4차 산업혁명 시대 창업의 국가경제적 의의와 함께 대학생의 진로 대안으로서 주목받고 있지만 우리나라 대학생의 창업인식은 낮은 수준에 머물고 있다. 대학생의 창업아이템이 글로벌 경쟁력을 갖출 만큼의 창의성이 뒷받침된 기술기반 창업과는 거리가 먼 경우가 많다. 최근 정부 및 대학에서 창업의 중요성을 인식하고 다양한 지원정책과 교육 프로그램을 운영하고 있다. 그러나 창업문화 확산을 통한 창업도전의 저변 확대, 시장과 산업 트랜드를 바꿀만큼의 시장 전환적이며, 창조적 파괴가 동반된 창업을 활성화하는 데에는 부족함이 많다. 이에 본 연구는 H대학교 신입생 1,092명을 대상으로 설문조사를 실시하여 대학생 창업인식을 분석하고 대학의 창업교육 고도화를 위한 유의한 사실을 발견하였다. 실태조사 결과를 이용하여 본 연구는 다음과 같은 창업교육 고도화 방안을 제시하였는데. 첫째, 생애주기적 진로대안으로서 창업의 의의 인식, 둘째, 학생의 개인적 특성에 기초한 맞춤형 창업교육 프로그램의 개발 운영, 셋째, 창업 전문성을 갖추면서 동시에 교육자로서의 역량을 갖춘 대학 내 외부 전문가들을 네트워킹하여 이론-실무의 우수한 창업 교육자 풀 구성 넷째, 효과적 창업교육 전략 및 프로그램 개발과 실행을 위한 구체적 대안으로 창업교육 목적의 명확화, 교육목적에 부합하는 실천적 교육 콘텐츠 개발 및 국내외 우수 창업교육 콘텐츠의 적극적 활용, 창의적 문제해결 능력 강화를 위하여 교육학적으로 효과적인 방법의 모색 등을 제시하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.4
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• pp.357-368
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• 1993

With the assumption of the diffusion dominated flow, a numerical model has been developed for undertow and turbulence structure under the breaking wave by using the $textsc{k}$-$\varepsilon$ turbulence model. Undertow is a strong mean current which moves seqwards below the level of wave trough in the surf zone. The turbulence, generated by wave breaking in the roller, spreads and dissipates downwards. The governing equations are composed of the equation of motion with the period-averaged shear stress due to waves; $textsc{k}$- and $\varepsilon$-equations with the turbulence energy Production due to wave breaking. They are discretised by the three-level fully implicit scheme, which can be solved by using Thomas algorithm. The model gives good agreements with measurements except for the station that is closest to the breaking point.

• Journal of KIISE:Databases
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• v.31 no.3
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• pp.297-306
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• 2004

Push-based broadcasting in wireless information services is a very effective technique to disseminate information to a massive number of clients when the number of data items is small. When the database is large, however, it nay be beneficial to integrate a pull-based (client-to-server) backchannel with the push-based broadcast approach, resulting in a hybrid data delivery. In this paper, we analyze the performance behavior of a predeclaration-based transaction processing, which was originally devised for a push-based data broadcast, in the hybrid data delivery through an extensive simulation. Our results show that the use of predeclaration-based transaction processing can provide significant performance improvement not only in a pure push data delivery, but also in a hybrid data delivery.

• Electrical & Electronic Materials
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• v.8 no.5
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• pp.611-618
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• 1995

The (Sr$_{1-x}$ .Ca$_{x}$)TiO$_{3}$+0.6[mol%]Nb$_{2}$O$_{5}$ (0.05.leq.x.leq.0.2) ceramics were fabricated to form semiconducting ceramics by sintering at about 1350[.deg. C] in a reducing atmosphere(N$_{2}$ gas). Metal oxides, CuO, was painted on the both surface of the specimens to diffuse to the grain boundary. They were annealed at 1100 [.deg. C] for 2 hours. The 2nd phase formed by thermal diffusing from the surface lead to a very high apparent dielectric constant. According to increase of the frequency as a functional of temperature, all specimens used in this study showed the dielectric relaxation, and the relaxation frequency was above 106 [Hz], it move to low frequency with increasing resistivity of grain. The specimens showed three kinds of conduction mechanisms in the temperature range 25-125 [.deg. C] as the current increased: the region I below 200 [V/cm] shows the ohmic conduction. The region rt between 200 [V/cm] and 2000 [V/cm] can be explained by the Poole-Frenkel emission theory, and the region III above 2000 [V/cm] is dominated by the tunneling effect.fect.