• 펄프종이기술
• /
• 제48권2호
• /
• pp.83-90
• /
• 2016

Increasing the amount of filler in paper is of high interest for paper industry while maintaining its key sheet quality properties. In this study, a MFC-GCC composite, made through a co-grinding NBSK (Northern bleached softwood kraft) pulp with a ground calcium carbonate (Intracarb 60), was used as a strength aid in paper in order to evaluate a potential cost reduction through filler increase without sacrificing paper quality. Hand-sheets were made of NBSK and/or eucalyptus pulp by using white water recirculation in a Tappi sheet former and was compared its properties without or with MFC additions at different filler levels. It was found that the MFC-GCC composite has a large surface area compared to the fiber, allowing the formation of more hydrogen bonds in the web, thus giving natural strength to the paper. Overall results are encouraging that the MFC-GCC composite allows papermaker to reduce basis weight and maintain critical sheet properties.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2000년도 추계학술대회
• /
• pp.129-135
• /
• 2000

Four types of land use were selected for sampling and study with different characteristics of heavy metal contamination during the period from August 1998 to June 2000. A series of studies have been carried out concerning the physicochemical characteristics of the sediments settling down in a gully pot to evaluate the contamination of Pb, Zn, Cd, Co, Cr and Cu. An examination of six elements indicated that Zn, Cu and Pb were the heavy metals severely impacted by anthropogenic input in Seoul. An assessment of 60 volatile organic compounds (VOCs) in urban runoff and ground water was conducted based on samples collected from 31 sites and 12 wells, respectively, in Seoul City. The higher levels of alkyl benzenes in urban runoff indicated that Seoul areas were mainly contaminated through traffic sources.

• Journal of Plant Biology
• /
• 제16권3_4호
• /
• pp.1-6
• /
• 1973

The distribution of plant communities along the Bukhan Riverside in Chun-seong was studied by means of the methods fo Curtis and Pattern. The communities were arranged in a single-dimensioned ordination on the basis of the importance values of the persistent species. Leading dominant species, form the 'low' level to the 'high' levels of the ordination gradient, were Phalaris arundinacea, Salix gilgiana, Artemisia feddei, Zoysia japonica, Pennisetum japonicum, and Arundinella hirta. These species from a continuum from the river to the dry grassland depending upon available soil-moisture. Standing crops in terms of dry weight and the nitrogen content of the above-ground parts of these species showed a good relationship with gradients of available soil-moisture.

• 한국물환경학회지
• /
• 제25권2호
• /
• pp.193-204
• /
• 2009

The study was conducted investigation on land of D-dong in N city which is an urban area and D myeon of N city which is a suburban area, based on high resolution satellite image, to find out actual land usage. As for D-dong in N city, different rate between actual usage and official land information was 0.5~4.8% in terms of 5 major land types (paddy field, farm, ground, forest, and others). D myeon in N city posted 1.4~8.4%, which is higher than that of its counterpart. As for unit load, "land" which is large in terms of load presented a big difference between official information and actual usage. On the other hand, the levels of paddy, field, forest and others posted only small changes in load. In case of T-P, in particular, unit of each land type is lower than BOD and T-N, showing almost no changes in pollution loads.

• 천문학회보
• /
• 제40권2호
• /
• pp.42.2-43
• /
• 2015

Massive stars play a major role in the interstellar energy budget and the shaping of the galactic environment. The water molecule is thought to be a sensitive tracer of physical conditions and dynamics in star-forming regions because of its large abundance variations between hot and cold regions. Herschel/HIFI allows us to observe the multiple rotational transitions of H2O including the ground-state levels, and its isotopologues toward high-mass star-forming regions in different evolutionary stages. Photodissociation regions (PDRs) are also targeted to investigate the distribution of water and its chemistry. We present line profiles and maps of H2O using data from two guaranteed-time key programs "Water In Star-forming regions with Herschel" and "Herschel observations of EXtra-Ordinary Sources". We analyze the temperature and density structures using LTE and non-LTE methods. We also estimate turbulent and expansion velocities, and abundance of water in the inner and outer envelopes using the 1D radiative transfer code. Around high-mass protostars we find H2O abundances of ~10-8-10-9 for the outer envelope and ~10-4-10-5 for the inner envelope, and expansion and turbulent velocities range from 1.0 km s-1 to 2.0 km s-1. The abundances and kinematic parameters of the sources do not show clear trends with evolutionary indicators. The Herschel/HIFI mapping observations of H2O toward the Orion Bar PDR show that H2O emission peaks between the shielded dense gas and the radicals position, in agreement with the theoretical and the observational PDR structure. The derived H2O abundance is ~10-7 and peaks at the depth of AV ~8 mag from the ionization front. Together with the low ortho-to-para ratio of H2O (~1) presented by Choi et al. (2014), our results show that the chemistry of water in the Orion Bar is dominated by photodesorption and photodissociation.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2016년도 학술발표회
• /
• pp.519-519
• /
• 2016

Upper Chenab Canal (UCC) is a non-perennial canal in Punjab Province of Pakistan which provides irrigation water only in summer season. Winter and summer are two distinct cropping season with an average rainfall of about 161 mm and 700 mm respectively. Wheat-rice is common crop rotation being followed in the UCC command area. During winter season, groundwater and rainfall are the main sources of irrigation while canal and ground water is used to fulfil the crop water requirements (CWR) during summer. The objective of current study is to estimate how the irrigation water requirements (IWR) of the two crops are going to change under different conditions of temperature and rainfall. For this purpose, 12 different climatic scenarios were designed by combining the assumptions of three levels of temperature increase under dry, normal and wet conditions of rainfall. Weather records of 13 years (2000-2012) were obtained from PMD (Pakistan Meteorological Department) and CROPWAT model was used to simulate the IWR of the crops under normal and scenarios based climatic conditions. Both crops showed a maximum increase in CWR for temperature rise of $+2^{\circ}C$ i.e. 8.69% and 6% as compared to average. Maximum increment (4.1% and 17.51% respectively) in IWR for both wheat and rice was recorded when temperature rise of $+2^{\circ}C$ is coupled with dry rainfall conditions. March & April during winter and August & September during summer were the months with maximum irrigation requirements. Analysis also showed that no irrigation is needed for rice crop during May and June because of enough rainfall in this area.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2002년도 학술.기술논문발표회
• /
• pp.87-91
• /
• 2002

This paper investigates the corrosion inhibition and the reduction of hydration heat properties of Ground Granulated Blast-Furnace Slag (GGBFS) added concrete. Since the massive civil structure is vulnerable to the thermal crack by hydration. adiabatic temperature rising tests were performed for water-binder ratios from 43.2% to 47.3%, while replacing 15% to 50% of cement with GGBFS of equal weight. Then, the corrosion protection performance was evaluated using cylindrical specimens embedded with steel reinforcement according to the combination of 3 W/B ratios and 2 levels of chloride ion quantity. The corrosion area of the embedded steel ban was determined using the high pressure steam curing method specified in KS F 2561. The test results showed that the replacement of GGBFS was effective in reducing the hydration heat. The corrosion area of the embedded steel ban decreased as the replacement of GGBFS increased. However, the corrosion area of the steel bar was proportional to the autoclave cycle and the chloride ion quantity. Among the tested specimens, compressive strength, reduction of hydration heat, and corrosion inhibition performance were excellent when 50% of cement was replaced with GGBFS of equal weight.

• 한국식품저장유통학회지
• /
• 제23권5호
• /
• pp.631-637
• /
• 2016

커피박의 식품소재화를 위해 생리활성과 양갱 제조시 활용 가능성을 검토하기 위해 커피박 열수추출물 첨가 양갱(CREY)와 커피박 분말 첨가 양갱(CREP)를 제조하였다. 커피원두와 커피박 열수 추출물의 총 폴리페놀 함량과 DPPH 라디칼 소거능은 각각 $13.65{\mu}g/mL$와 78.75 %를 나타내었다. pH는 대조구가 7.42, CREY는 7.10~7.29의 범위를 나타내었고, CRPY는 6.95~7.15의 범위를 나타내었다. CREY의 수분 함량은 37.88~38.92%, CRPY는 39.3~40.0%의 범위로 대조구(36.34%)보다 높은 수분함량을 나타내었다. 당 함량은 대조구가 가장 높았다. 총 폴리페놀 함량은 CREY가 $15.88{\sim}66.19{\mu}g/mL$, CRPY는 $12.09{\sim}23.80{\mu}g/mL$의 범위를 나타내어 CRE와 CRP의 첨가농도(0.1, 0.3, 0.5 및 1.0 %)에 따라 유의적으로 증가하였다(p<0.05). DPPH 라디칼 소거능은 대조구가 1.88%, CREY는 8.77~43.10%로 농도 의존적으로 증가하였으며, CRYP도 5.28~14.92%의 범위를 나타내어 대조구보다 유의적으로 높았다(p<0.05). 양갱의 관능검사 결과, 색, 맛과 풍미 모두 CREY와 CRPY가 대조구에 비해 우수하였으며, 커피박 열수 추출물을 사용할 경우 0.5%, 커피박 분말을 사용할 경우 0.3%를 첨가한 양갱이 관능적으로 가장 우수하였다.

• 한국수자원학회논문집
• /
• 제55권11호
• /
• pp.903-911
• /
• 2022

물을 공급하기 위한 자원 중 하나인 지하수는 다양한 자연적 요인에 의해 수위의 변동이 발생한다. 최근, 인공신경망을 이용하여 지하수위의 변동을 예측하는 연구가 진행되었다. 기존에는 인공신경망 연산자 중 학습에 영향을 미치는 Optimizer로 경사하강법(Gradient Descent, GD) 기반 Optimizer를 사용하였다. GD 기반 Optimizer는 초기 상관관계 의존성과 해의 비교 및 저장 구조 부재의 단점이 존재한다. 본 연구는 GD 기반 Optimizer의 단점을 개선하기 위해 GD와 화음탐색법(Harmony Search, HS)를 결합한 새로운 Optimizer인 Gradient Descent combined with Harmony Search(GDHS)를 개발하였다. GDHS의 성능을 평가하기 위해 다층퍼셉트론(Multi Layer Perceptron, MLP)을 이용하여 이천율현 관측소의 지하수위를 학습 및 예측하였다. GD 및 GDHS를 사용한 MLP의 성능을 비교하기 위해 Mean Squared Error(MSE) 및 Mean Absolute Error(MAE)를 사용하였다. 학습결과를 비교하면, GDHS는 GD보다 MSE의 최대값, 최소값, 평균값 및 표준편차가 작았다. 예측결과를 비교하면, GDHS는 GD보다 모든 평가지표에서 오차가 작은 것으로 평가되었다.

• 한국작물학회지
• /
• 제39권6호
• /
• pp.577-584
• /
• 1994

수원지역에서 토성 및 지하수위를 달리하는 서울대 농생대 벼 재배 실험포장(사양토)과 작물시험장 벼 재배포장(식양토)을 선정하여 월동 청예 사료작물 3가지와 하기 청예사료작물 4가지에 대한 생육 및 수량반응을 검정하고 초기 전환밭에서 재배에 적합한 작물의 검색과 토성 및 지하수위에 따른 작물별 반응을 알아보기 위하여 1992년과 1993년에 실시한 실험 결과를 요약하면 다음과 같다. 1. 시험된 7종의 사료작물들은 지하수위가 낮고 상대적으로 사질성인 서울대 농생대 벼 재배포장에서 더 좋은 생육 및 수량을 보였으며, 두 포장 모두 하기 청예용 사료작물의 재배시에는 습해의 위험이 있는 것으로 나타났다. 2. 월동 청예용 사료작물 중에서는 트리티케일이 평균 1052kg/10a로 가장 높은 건물수량을 나타내었으며 두 포장간의 건물수량 차이도 보이지 않아 전환 밭에서의 월동 작물로 재배가 유리할 것으로 생각되었으며, 호밀은 두 포장간의 차이가 있어서 토성 및 지하수위에 따른 영향이 있었고, 이탈리안라이그라스는 평균 41.6%의 낮은 월동률을 보여 위도가 높은 수원지역에서는 전환밭 재배에 적합하지 못한 것으로 나타났다. 3. 하기 청예사료작물 중에서는 수수-수단그라스 잡종이 평균 1139kg /10a 로 가장 높은 건물수량을 나타내었다. 수수-수단그라스 잡종과 진주조, 사료용 옥수수는 토성간의 건물수량의 차이가 있어서 식양토 전환밭에서는 습해의 가능성이 높을 것으로 생각되며 사료용 피는 두 포장간에 수량차이가 없었다.