낙동강하구 갈대군락의 성장에서 지상부제거에 따른 영향

김구연 ( Gu Yeon Kim ),박희순 ( Hee Sun Park ),주기재 ( Gea Jae Joo ) 한국환경생태학회 2007 한국환경생태학회 학술대회지 Vol.2007 No.1

CMP 연마입자의 마찰력과 연마율에 관한 영향

김구연,김형재,박범영,이현섭,박기현,정해도,Kim, Goo-Youn,Kim, Hyoung-Jae,Park, Boum-Young,Lee, Hyun-Seop,Park, Ki-Hyun,Jeong, Hae-Do 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.10

Chemical Mechanical Polishing (CMP) is referred to as a three body tribological system, because it includes two solids in relative motion and the CMP slurry. On the assumption that the abrasives between the pad and the wafer could be a major reason not only for the friction force but also for material removal during polishing, the friction force generated during CMP process was investigated with the change of abrasive size and concentration of CMP slurry. The threshold point of average coefficient of friction (COF) with increase in abrasives concentration during interlayer dielectric (ILD) CMP was found experimentally and verified mathematically based on contact mechanics. The predictable models, Mode I (wafer is in contact with abrasives and pad) and Mode II (wafer is in contact with abrasives only), were proposed and used to explain the threshold point. The average COF value increased in the low abrasives concentration region which might be explained by Mode I. In contrast the average COF value decreased at high abrasives concentration which might be regarded to as Mode II. The threshold point observed seemed to be due to the transition from Mode I to Mode II. The tendency of threshold point with the variation of abrasive size was studied. The increase of particle radius could cause contact status to reach transition area faster. The correlation between COF and material removal rate was also investigated from the tribological and energetic point of view. Due to the energy loss by vibration of polishing equipment, COF value is not proportional to the material removal rate in this experiment.

낙동강 하류에서 수서무척추동물에 의한 정수식물의 낙엽분해

김구연(Gu Yeon Kim),주기재(Gea Jae Joo),김현우(Hyun Woo Kim),신건성(Geon Seong Shin),윤해순(Hae Soon Yoon) 한국하천호수학회 2002 생태와 환경 Vol.35 No.3

Leaf litter breakdown rates of the Phragmites australis, Ziznia latifolia and Typha angustifolia were determined at the lower Nakdong River from Nov. 1998 to Sept. 1999. The relationship between leaf litter breakdown of three and abundance of aquatic invertebrates was investigated. Aquatic invertebrates collected in the litterbags were 11 family, 11 species(mean density: 222 ind./㎡, n=792), and Chironomidae was dominant. Mean density of Chironomidae in the litterbags were different according to the aquatic plant species: Z. latifolia(180 ind./㎡, n=264) T. angustifolia(187 ind./㎡, n=264) P. australis(95 ind./㎡, n=264). The breakdown of Z. latifolia was the shortest, and that of T. angustifolia was shorter than P. australis. Overall, the breakdown rate at floating layer was faster than that of submerged layer in all of three species and differences of the breakdown rate between open bags and closed bags were not found.

서낙동강 본류 및 낙동강 둔치 습지의 수생식물 생물량 분포

김구연 ( Gu Yeon Kim ),김지윤 ( Ji Yoon Kim ) 한국하천호수학회(구 한국육수학회) 2014 생태와 환경 Vol.47 No.1

Standing crop distribution of aquatic plants in the West Nakdong River and riparian wetlands in the Nakdong River were surveyed in May, July and September, 2010. Total 25 aquatic macrophyte species (submerged: 9, leaf-floating: 3, free-floating: 5, emergent: 8) were observed during the survey periods. Distribution area of aquatic plants and proportion of submerged communities were highest in Garakchi-deung (212,032 m2, 72.7%). The distribution area of aquatic plants was highest in Phragmites australis community (421,584 m2), followed by Hydrilla verticillata-Vallisneria natans community (181,511 m2), Potamogeton wrightii-Vallisneria natans community (61,604m2), and Hydrocharis dubia community (49,709m2). Garakchideung (212,032 kg) also had the highest aquatic plant production, followed by Suanchi-deung (15,546 kg), Daedong (5,813 kg), Dunchi-do (3,963 kg), Maekdo (1,463 kg), Yeommak (571 kg), Jungsa-do (530 kg), and Shinan (300 kg). Average standing crop of the study area were 147.8±20.8 g DW.m-2 in 1988, 96.1±20.0 g DW.m-2 in 2000, and 172.6±76.1 g DW.m-2 in 2010. For a sustainable management of river habitat and food source, aquatic plant should concurrently be surveyed with river environmental variables (i.e. sediment, nutrient, flow).

우포늪 물억새(Miscanthus sacchariflorus) 군락에서 생장초기에 잘라주기와 태워주기에 따른 성장변화

김구연 ( Gu Yeon Kim ),이찬우 ( Chan Woo Lee ),주기재 ( Gea Jae Joo ) 한국하천호수학회 2004 생태와 환경 Vol.37 No.2

Growth patterns after the cutting and burning of Miscanthus sacchariflorus community were analyzed in the Woopo Wetland. Three replicates of 5 × 5 m plot of control, burning, and cutting treatments were established in April 2003 and changes of growth pattern were monitored by August 2003. In the control, burning, and cutting plots, a total of 7 families and 8 species, 14 families and 18 species, 6 families and 8 species were observed respectively. Burning plot showed high diversity of flora. However, high diversity declined after July and all plots showed a similar species diversity. Vine plant, Humulus japonicus, dominated in the burning plots. Change of shoot density was highest in the early period in the burning plots (176/㎡) and shoot density in early May was almost double of the control and cutting plots. Toward to the end of active growth period (August), shoot density in cutting plot (170±7/㎡) was higher than that of burning plots (141±9/㎡). Shoot length of the cutting, burning, and control plot was 205±15 cm, 196±17 cm, and 187±6 ㎝ (n>100) respectively. Above-ground biomass of cutting plots was higher than that of burning and control plots. Above-ground biomass of cutting plot was 1.6 times higher than the control while burning plot showed 1.4 times. This study indicted that cutting of Miscanthus sacchariflorus community increase shoot density development, length growth, and above-ground biomass.

상피세포성장인자 고정화를 위한 저분자 수용성 6-Amino-6-Deoxychitosan의 제조와 생체적합성

김구연 ( Koo Youn Kim ),박보기 ( Bo Gi Park ),김광일 ( Kwang Il Kim ),손태일 ( Tae Il Son ) 한국키틴키토산학회 2008 한국키틴키토산학회지 Vol.13 No.2

버드나무류 (Salix spp.)의 계절학적 특성과 주요 기상요인 상관분석

김성보 ( Seong Bo Kim ),김지윤 ( Ji Yoon Kim ),임란영 ( Ran Young Im ),도윤호 ( Yuno Do ),박희순 ( Hee Sun Park ),주기재 ( Gea Jae Joo ),김구연 ( Gu Yeon Kim ) 한국환경과학회 2013 한국환경과학회지 Vol.22 No.12

The objective of this study was to analyze correlation between phenological characteristics of Salix spp. and meteorological factors in the Upo wetlands. Phenology of Salix subfragilis Andersson and Salix chaenomeloides Kimura was monitored from 2007 to 2012. Meteorological variables were monitored by Korea Meteorological Administration (Hap-chon). Average date of flowering, fruiting, seed dispersion was 86, 113, 136 days for S. subfragilis and 112, 140, 164 days for S. chaenomeloides as Julian days. Flowering of S. subfragilis and S. chaenomeloides were correlated with daily mean air temp. in March (r=-0.92, r=-0.85, p<0.05). Fruiting of S. subfragilis was correlated with total precipitation between Jan and March of previous year (r=-0.90, p<0.01), however, the fruiting of S. chaenomeloides was highly correlated with max. temp. in Jan of previous year (r=0.99, p<0.01). Seed dispersion of both species is correlated with min. temp. in Feb. Phenology monitoring will contribute to understanding Salix spp. response against climate change.

중등 수학과 서술형평가 체계의 실제와 대안적 발전 방향 모색 -경기도 창의,서술형 평가와 미국 오하이오 주 평가를 중심으로

김래영 ( Rae Young Kim ),김구연 ( Goo Yeon Kim ),노선숙 ( Sun Sook Noh ),김민경 ( Min Kyeong Kim ),전지훈 ( Ji Hoon Jeon ),김기영 ( Ki Young Kim ),이민희 ( Min Hee Lee ) 한국수학교육학회 2012 수학교육논문집 Vol.26 No.3

최근 서술형 평가의 비중이 확대되고 있는 가운데, 본 연구에서는 선행 연구들을 바탕으로 경기도 창의·서술형 평가와 미국 오하이오 주 평가의 서술형 평가에서 제시한 서술형 평가 체계에 대한 대안적 발전 방향을 모색하였다. 분석 결과, 서술형 평가의 정의와 측정하고자 하는 사고의 종류와 다양성뿐만 아니라, 두 평가가 제공하고 있는 평가관련 자료에 대한 접근 용이성 및 다양성, 교육당사자들에게 제공하는 자료의 구체성 및 실용성, 서술형 문항의 채점 방법과 기준, 그 활용에 있어서도 많은 차이점들이 발견되었다. 연구 결과를 종합하여 볼 때, 우리나라 현 서술형 평가 체제에서 학생들의 다양한 능력을 발휘하고 평가할 수 있는 문항 개발, 교육당사자들에게 명확하고 구체적인 정보 제공, 효율적인 서술형 평가 체제의 강화가 필요함을 알 수 있었다. The purpose of this study is to investigate how constructed-response assessments are currently defined and used to find an alternative way of developing well-defined constructed-response questions and an assessment system. Based on our review of the literature, we analyze constructed-response assessments developed and used in Gyeonggi-do, South Korea and Ohio, U.S.A in terms of their definitions, types of questions, information and guidelines given by the government agencies in each place, and scoring rubrics and their use. The results provide meaningful implications for the development of constructed-response assessments in the future.

낙동강하구 을숙도 갯벌에서 새섬매자기의 생육 특성

김구연,Kim, Gu-Yeon 한국하천호수학회 2020 생태와 환경 Vol.53 No.4

Bolboschoenus planiculmis is an important prey species for winter migratory birds in the Nakdong River Estuary region, but its population has declined in the last decade due to a physio-chemical shift. To identify the growth and development characteristics of B. planiculmis, we carried out an experimental survey on the aboveground and belowground sections of B. planiculmis specimens in the Eulsuk tidal flat from April to September 2019. We divided the belowground area into two groups: a vegetation group in which B. planiculmis exists and a non-vegetation group in which B. planiculmis does not exist and measured the rate of tubers. We observed a 45% appearance frequency in the vegetation group and only a 5% frequency in the non-vegetation group, indicating that there were no supplies for plant growth. The mean density, length, and biomass of B. planiculmis aboveground were 166.90±149.62 n m^-2, 44.39±5.45 cm, and 67.63±54.46 g DW m^-2, respectively, which was approximately half of those obtained from the study in the Eulsuk tidal flat in 2002. Tuber number was the highest in the 15~25 cm deep layer(41.50%). The mean number of total tubers belowground was related to different sediment conditions(FS: flat surface, DS: disturbed surface) 251.75±16.86 n pot^-1 for FS and 171.00±25.18 n pot^-1 for DS, which was significantly different(total tubers: p<0.005). The mean biomass of B. planiculmis above-ground was 21.11±1.60 g DW pot^-1 for FS and 15.41±1.38 g DW pot^-1 for DS, which was significantly different(p<0.05). This research provides primary materials for the restoration of the Nakdong River Estuary, wintering sites for migratory birds, and protection of B. planiculmis.

한반도 동해 연안에 자생하는 말잘피, 새우말의 생장 특성

김종협,김재훈,김구연,박정임,KIM, JONG-HYEOB,KIM, JAE HOON,KIM, GU YEON,PARK, JUNG-IM 한국해양학회 2018 바다 Vol.23 No.4

말잘피 새우말은 북태평양에 위치한 북동아시아 연안의 암반에 자생한다. 우리나라에서 새우말은 주로 동해 중부해역의 암반조하대에 나타나며, 본 조사에서는 이 곳에 서식하는 새우말의 생태적 특성을 알아보기 위해, 2017년 8월부터 2018년 7월까지 새우말 군락지의 수중광량, 수온의 변화와 함께 매월 새우말의 형태적 특성, 밀도, 생체량과 잎 생산성의 변화를 조사하였다. 수중광량과 수온은 봄과 여름에 증가하고 가을과 겨울에 감소하는 뚜렷한 계절 경향을 보였다. 새우말의 형태, 밀도, 생체량과 잎 생산성은 겨울과 봄에 증가하고, 여름과 가을에 감소하였다. 새우말의 개체당 잎 생산성과 단위면적당 잎 생산성은 수중광량과 유의한 양의 상관관계를 보였다. 새우말의 연간 평균 단위면적당 잎 생산량은 $6.3{\pm}1.3g\;m^{-2}d^{-1}$로, 2018년 5월 최대값($16.4{\pm}4.4g\;m^{-2}d^{-1}$)과 2월에 최소값($2.4{\pm}0.3g\;m^{-2}d^{-1}$)을 나타내었다. 새우말 생장의 최적 수온은 $12-13^{\circ}C$로 조사되었다. The surfgrass Phyllospadix iwatensis is native in the exposed rocky shores of the Northwestern Pacific Ocean. In Korea, P. iwatensis is mainly found on the rocky subtidal zone in the central eastern coast. In this study, to examine the ecological characteristics of P. iwatensis, we investigated changes in morphological characteristics, density, biomass, and leaf productivity as well as changes in the underwater irradiance and water temperature of its habitat monthly from August 2017 to July 2018. Underwater irradiance and water temperature showed clear seasonal changes; increases in spring and summer and decreases in fall and winter. Morphological characteristics, shoot density, biomass, and leaf productivities of P. iwatensis exhibited significant seasonal variations, increasing in winter and spring and decreasing in summer and fall months. P. iwatensis leaf productivities both per shoot and per unit area showed significant positive correlations with underwater irradiance. The average leaf productivity of P. iwatensis per area was $6.3{\pm}1.3g\;m^{-2}d^{-1}$, while minimum and maximum values were $2.4{\pm}0.3g\;m^{-2}d^{-1}$ in February 2018 and $16.4{\pm}4.4g\;m^{-2}d^{-1}$ in May 2018, respectively. The optimum water temperature for the growth of P. iwatensis in this study was between $12-13^{\circ}C$.