• Title/Summary/Keyword: 혼합대

Search Result 914, Processing Time 0.026 seconds

The Behaviour of Dissolved Iron and its Variability in the Keum estuary, a Macrotidal System on the Western Coast of Korea (금강 하구에서의 용존 철 행동과 그 변화에 대한 연구)

  • LEE, CHANG-BOK
    • 한국해양학회지
    • /
    • v.27 no.2
    • /
    • pp.101-111
    • /
    • 1992
  • 용존 철의 행동과 시간적 변화에 대한 연구가 온대 대조차 환경인 금강 하구에서 이루어 졌다. 이지역에서 가장 중요한 환경변수인 하천배수량과 조차의 차이로 야기되 는 변화를 파악할 수 있도록 4번의 현장조사를 각각 다른 배수량과 조차의 시기에 실 시하였으며, 아울러 실험실 내에서 혼합실험도 행해졌다. 혼합실험의 결과 하천에 의 해 운반되는 용존 철의 90% 이상이 5$\textperthousand$ 이하의 저염분역에서 제거되는 현상이 확인되 었다. 그러나 현장조사에서 이러한 초기 혼합시의 용존 철 제거가 뚜렷이 나타난 것은 갈수기.소조기 3번의 다른 환경조건 하에서는 용존 철 농도의 심한 변화가 관측되었 다. 하천배수량과 조차의 변화에 따라 보여진 용존 철의 변화는 하구순환이나 퇴적물 재부유 및 응집체 해체 등의 물리적 현상과 관련시켜 해석되었다.

  • PDF

Application of Mixed HVAC in Large Sized Office Building (대형오피스 빌딩 혼합공조(시스템에어컨+중앙공조)적용사례)

  • 서경진;정기호
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
    • /
    • v.33 no.8
    • /
    • pp.23-31
    • /
    • 2004
  • 국내 시스템에어컨 시장은 신도시 형성과 주상복합건물 및 중대형 아파트의 전실공조 필요성이 증대하고 빌딩 리노베이션 등 지속적인 건설시장 성장에 따라 수요가 급격히 증가해 왔으며, 중대형 공조설비를 대체할 차세대 공조시스템으로 시장에서 평가받고 있으며, 상업용 공조시장에서 차지하는 비율도 점차 증가하고 있다. 이런 결과 지난해 3,000∼3,500억 원대의 시장 규모는 올해 4,500∼5,000억 원대로 성장이 예상되면, 매년 30% 이상의 지속적인 시장확대가 예측되며, 도입초기에 주상복합, 아파트, 교단, 병원, 중소형 빌딩 등에 한정되었던 시장은 최근에는 중대형 빌딩용 멀티 에어컨의 수요가 꾸준히 늘어나고 있으며 선진시장인 일본에서 중앙공조 및 멀티에어컨의 장점만을 이용한 혼합 공조시스템이 90년대부터 적용되어져 왔으며, 현재에는 대형오피스 빌딩의 경우에도 공조방식이 시스템에어컨 및 혼합공조가 증가하는 추세이다. (중략)

  • PDF

Heavy Metal Contents of Gypsophila oldhamiana Growing on Soil Derived from Serpentine (사문암 지역에서 생육하는 대나물(Gypsophila oldhamiana)의 중금속 함량)

  • 김명희;민일식;송석환
    • The Korean Journal of Ecology
    • /
    • v.20 no.5
    • /
    • pp.385-391
    • /
    • 1997
  • To investigate the degrees of toxification in the serpentine areas, serpentinites and adjacent metamorphic rocks and soils from the serpentinite, metamorphic area and transitional area(mixed soil) between serpentinite and metamorphic rocks are collected from the Hongseong-Gun, Chungnam. A plant, Geochemically, the serpentinites are high in the nickel, chromium and cobalt content whereas the metamorphic rocks show high zinc, scandium, molybdenum and iron contents. The serpentine soils are high in the nickel, chromium and cobalt contents whereas the non-serpentine soils show high zinc and iron contents. Heavy metal contents in the G. oldhamiana are high in the serpentine soil relative to the mixed soil. Ratio of the iron to nickel contents for the G. oldhamiana are low in the serpentine soil(49) relative to the mixed soil(216). Of the G. oldhamiana, most of the heavy metal contents except zinc and molybdenum are high in the root relative to the aboveground vegetation. Comparing with rocks, the G. oldhamiana is low in the all of heavy metal contents relative to the serpentinite. Uptake of zinc by the G. oldhamiana is high in the serpentinites and metamorphic rocks whereas uptake of scandium and iron by the G. oldhamiana is very high in the serpentinite area.

  • PDF

Experimental study on the sediment sorting processes of the bed surface by geomorphic changes in the vegetated channels (실내실험에 의한 혼합사 식생하도의 지형변화와 하상토 분급 특성 연구)

  • Jang, Chang-Lae
    • Journal of Korea Water Resources Association
    • /
    • v.49 no.1
    • /
    • pp.73-81
    • /
    • 2016
  • This study investigates the development of lower channels and sediment sorting processes in the vegetated channels with the mixed sediment. The sediment discharges fluctuate with time and decrease with vegetation density. The bed changes with irregular patterns, and the sediment particles in the vegetated zone at the surface of bed are fine. The dimensionless geometric mean decreases with vegetation density. The fine sediment particles are trapped by vegetation, and the bed between main steam and vegetated zone increases. Moreover, the particle sizes are distributed irregularly near the zone. The hiding functions decrease with dimensionless particle size. However, the functions increase with vegetation density, which is confirmed by decreasing sediment discharge with vegetation. The lower channel is stable and the migration decreases in the condition of $0.5tems/cm^2$. However, the migration of the lower channel in the condition of $0.7stems/cm^2$ increases due to the increased sinuosity and new generated channels in the sedimentated vegetation zone.

A Survey on the Preferences and Recognition of Multigrain Rice by Adding Grains and Legumes (곡류와 두류를 혼합한 잡곡밥의 기호도 및 인식 조사)

  • Jang, Hye-Lim;Im, Hee-Jin;Lee, Yu-Jin;Kim, Kun-Woo;Yoon, Kyung-Young
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.41 no.6
    • /
    • pp.853-860
    • /
    • 2012
  • This study investigated the preference and recognition of cooked rice mixed with multigrains. The data for the analysis was collected from 464 people who were residing in Seoul, Gyeongsang and Jeolla area, and analyzed by the SPSS 18.0 program. The result showed that 77.8% of the respondents liked cooked rice mixed with multigrain, showing significant difference by age (p<0.001) and occupation (p<0.01). Of the respondents, 33.8% consumed cooked rice mixed with multigrains at least once a day, showing significant difference by gender (p<0.01), age (p<0.001) and occupation (p<0.001). The most popular type of grains to mix with rice were, in order, black rice (3.8)> brown rice (3.7)> barley (3.7)> proso millet (3.4)> foxtail millet (3.4)> SoRiTae (3.3)> sorghum (3.2)> adlay (3.2)> mung bean (3.1)> buckwheat (3.0)> BacTae (2.8). A total of 32.5% of the respondents answered that 21~30% was proper mixing ratio of multigrains-added cooked rice, showing age (p<0.001), occupation (p<0.001) and resident area (p<0.05). Three or four kinds of grains were preferred to mix cooked rice, showing significant difference by age and occupation (p<0.001). Of the respondents, 43.1% chose price reduction as the most desired improvement of multigrains in the market. Most of the subjects had affirmative view intake of cooked rice mixed with multigrains, but recognized that multigrains were expensive. From these results, this study will provide basic information for the increased availability of multigrains and optimization of the multigrain ratio mix.

Error Analysis of Linear Mixture Model using Laboratory Spectral Measurements (실내 분광 측정자료를 이용한 선형혼합모델의 오차 분석)

  • Kim, Sun-Hwa;Shin, Jung-Il;Shin, Sang-Min;Lee, Kyu-Sung
    • Korean Journal of Remote Sensing
    • /
    • v.23 no.6
    • /
    • pp.537-546
    • /
    • 2007
  • In hyperspectral remote sensing, linear spectral mixture model is a common procedure decomposing into the components of a mixed pixel and estimating the fraction of each end-member. Although linear spectral mixture model is frequently used in geology and mineral mapping because this model is simple and easy to apply, this model is not always valid in forest and urban area having rather complex structure. This study aims to analyze possible error for applying linear spectral mixture model. For the study, we measured laboratory spectra of mixture sample, having various materials, fractions, distributions. The accuracy of linear mixture model is low with the mixture sample having similar fraction because the multi-scattering between components is maximum. Additionally, this multi-scattering is related to the types, fraction, and distribution of components. Further analysis is necessary to quantify errors from linear spectral mixture model.

Effects of UF Resin and Taro Adhesive Mixture on Plywood Bonding Strength (요소수지(尿素樹脂)와 토란접착제(土卵接着劑) 혼용(混用)이 합판(合板)의 접착력(接着力)에 미치는 영향(影響))

  • Lee, Phil-Woo;Park, Heon
    • Journal of the Korean Wood Science and Technology
    • /
    • v.12 no.1
    • /
    • pp.3-10
    • /
    • 1984
  • Taro-UF mixed type resin system was developed for gluing plywoods. The taro adhesive that was activated with sodium hydroxide was mixed with the definite ratios of UF resin adhesive. At the sametime, wheat-UF mixed type resin was also applied with the same method as taro-UF mixed type resin The mixing ratios of taro or wheat adhesive: UF resin were 0:100, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 80:20, and 100:0 by weight. In addition, the UF resins extended with wheat powder at the extending ratios of wheat powder UF resin, 10:90, 20:80, 30:70, 40:60, and 50:50 by weight, were also used. The dry and wet shear strengths of the plywoods of 30:70 (taro adhesive : UF resin) mixing ratio were highest. The dry shear strengths of the plywoods manufactured with the UF resin-mixing taro adhesive were higher than those of the plywoods with the UF resin-mixing wheat adhesive at 10:90, 20:80, 30:70, 40:60, 50:50, and 60:40 (taro or wheat adhesive: UF resin) mixing ratios. At all mixing ratios, the wet shear strengths of the plywoods manufactured with the UF resin-mixing taro adhesive were higher than those of the plywoods with the UF resin-mixing wheat adhesive. The dry and wet shear strengths of the plywoods manufactured with the UF resin-mixing wheat adhesive were higher than those of the plywoods with the wheat powder-extending UF resin at the mixmg ratios, 10:90, 20:80, 30:70, and 40:60 (wheat adhesive or wheat powder: UF resin). So, it was found that the plywoods manufactured with the UF resin-mixing taro adhesive and the UF resin mixing wheat adhesive had better shear strength than the plywoods with the wheat powder-extending UF resin. It was because the taro adhesive and wheat adhesive themselves took the bonding properties after being activated with alkali.

  • PDF

Seasonal Variation Patterns of Tidal Flat Sediments in Semi-enclosed Hampyong and Kwangyang Bays, West and South Coasts of Korea (한반도 서해안과 남해안의 반페쇄된 만에서 조간대 퇴적물의 계절변화에 관한 비교 연구: 서해안의 함평만과 남해안의 광양만)

  • Ryu, Sang-Ock
    • Journal of the Korean earth science society
    • /
    • v.24 no.6
    • /
    • pp.578-591
    • /
    • 2003
  • To investigate the seasonal variation patterns of tidal flat sediments in semi-enclosed Hampyong and Kwangyang Bays, respectively west and south coasts of Korea, accumulation rate and grain-size in the sediments were monitored during 2${\sim}$4 years. The mud flats in the northern and eastern parts of Hampyong Bay were eroded in summer and deposited in winter, but mixed flats in the southern part of the bay show reversed seasonal variations to the mud flats. These variations are most likely connected with wave actions induced by monsoon and physiographic setting of the tidal flats in the bay. In contrast, the tidal flats of Kwangyang Bay were eroded in summer and deposited in other seasons except summer, different from the case of Hampyong Bay. The physiography of Kwangyang Bay are characterized by dominant flood tides and weak wave actions. However, in summer, the surface sediments were abruptly eroded by occasional typhoons and heavy rainfall. These weather conditions appear to be important factors to accelerate erosion on the tidal flat in semi-enclosed bays, south coast of Korea.

기능성 카본계 막의 개발과 수처리 응용에의 검토에 관한 연구

  • Bae, Sang-Dae
    • Proceedings of the Korean Environmental Sciences Society Conference
    • /
    • 2006.05a
    • /
    • pp.431-434
    • /
    • 2006
  • 폴리머 라텍스의 탄화와 메탄-질소 혼합가스의 CVD법으로 Carbon whisker를 가진 활성탄막을 개발하였다. 이 막의 PMMA 현탁물질 여과실험과 실제의 현탁물질과 용존유기물을 함유한 오래된 수도관으로부터 얻어진 적수여과실험 결과, Carbon whisker의 유무가 fouling에 의한 막의 flux를 억제하는 것으로 밝혀져, 실제의 정수공정에의 응용 가능성을 보였다.

  • PDF