• Title/Summary/Keyword: 가소성

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Thermodynamic Studies on the Adsorption of 4-Octylphenol on Carboxen by GC/MS Analysis (GC/MS 분석에 의한 4-Octylphenol의 Carboxen 흡착에 대한 열역학적 연구)

  • Lee, Joon-Bae;Park, Woo-Yong;Shon, Shungkun;Jung, Ji Eun;Jeong, Yong Ae;Gong, Bokyoung;Kim, Yu-Na;Kwon, O-Seong;Paeng, Ki Jung
    • Applied Chemistry for Engineering
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    • v.29 no.3
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    • pp.356-361
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    • 2018
  • It is common to analyze volatile organic compound (VOC) or semi-VOC (SVOC) in a sample composed of a complex matrix consisting of multiple components such as bloods through a separation process. Adsorption is a physical phenomenon in which certain components accumulate on the surface of other phases. In order to overcome difficulties in the pretreatment process, an adsorption is frequently used. Solid phase microextraction (SPME) equipment with porous carbon carboxen (CAR) is an example of adsorption application. In this study, the adsorption of 4-octylphenol to carboxen was examined. To do so, the extraction efficiency for such solvents as dichloromethane ($CH_2Cl_2$, DCM), ethylacetate ($CH_3COOC_2H_5$, EA) and diethylether ($C_2H_5OC_2H_5$, $Et_2O$) was studied and also the derivatization reaction for 4-octylphenol with reagents of bistrimethylsilyltrifluoroacetamide (BSTFA), methylchloroformate (MCF) and pentafluorobenzylbromide (PFBBr) was compared. The combination of DCM and BSTFA showed good performance thus they were adopted for this study. Thermodynamic adsorption experiments showed that the adsorption process was endothermic and Freundlich isotherm equation was more suitable than Langmuir isotherm. It was also found that the adsorption followed a pseudo-$2^{nd}$ order kinetic model.

FeO, $TiH_2$, Carbon 원료분말을 이용한 Fe-TiC 나노 복합분말 제조 및 소결

  • An, Gi-Bong;Kim, Ji-Sun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.10a
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    • pp.26-26
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    • 2011
  • Fe계 TiC 합금은 미량의 합금원소를 첨가시켜 경화능, 내식성, 내마모성 성질을 개선한 특수 공구용 재료로서 현재 절삭, 내마모성, 광산, 금형재료 등의 분야에 널리 사용되고 있다. 금속과 세라믹의 복합재료인 초경합금은 비열처리용 공구강으로 WC, TiC 등의 4, 5, 6족 금속탄화물에 Co, Ni, Fe등의 철족이 결합금속으로 소결한 복합재료로 WC-Co계 초경합금이 주종을 이루고 있으나, 전략 소재로서 고가인 Co 원료를 대체하기 위한 재료로서 초경재료의 고경도와 공구강의 경제성 및 가공성의 장점을 이용한 Fe-TiC계 초경합금의 연구가 다양하게 진행되고 있다. 본 연구에서는 Fe기지에 서브마이크론 크기의 미세한 TiC 입자가 균일하게 분산된 Fe-TiC 복합분말을 경제적으로 제조하기 위해 순수한 Fe, Ti 원료분말에 비해 단가가 낮고 미세 분쇄가 용이한 FeO, $TiH_2$ 분말을 고에너지 밀링 후 반응 열처리 시키는 유사 기계화학적 공정을 시도하였다. 조성비 Fe-30wt%TiC 복합분말을 제조하기위해 마이크론(micron) 크기의 FeO, $TiH_2$, C 분말을 사용하였고, 1단계로 FeO와 C을 고에너지 밀링으로 혼합 후 반응시켜 환원시키는 공정과 2단계로 이렇게 환원된 분말과 TiH2를 고에너지 밀링으로 다시 혼합, 분쇄한 후 반응열처리 하는 두 단계 공정을 사용하였다. FeO의 환원 단계에서는 $700{\sim}1,000^{\circ}C$ 온도 범위에서 1시간 유지하였고, 고에너지 밀링 시 밀링시간, 회전속도를 변수로 두고 실험하였다. 환원된 분말은 수평관상로를 이용해 아르곤분위기에서 $1,000{\sim}1300^{\circ}C$까지 1시간 유지하여 반응열처리시켜 Fe-TiC 복합분말을 제조하였다. 준비된 복합분말을 XRD와 FE-SEM, EDS, 입도분석기 (LPSA) 등을 이용해 분말의 형태와 특성, 상, 조성, 입도, 분산도 등을 조사하였다. 제조된 Fe-TiC 나노복합분말을 방전플라즈마소결(SPS) 과 상압소결 실험을 진행하였다. Fe-TiC 복합분말 제조공정의 첫 번째 단계인 FeO의 환원반응은 $800^{\circ}C$이상의 온도에서 Fe로 환원이 진행됨을 확인하였다. 두 번째 단계인 반응열처리공정에서는 $1,000^{\circ}C$ 이상에서 TiC가 형성됨을 XRD 상분석을 통해 확인할 수 있었고, $1,100^{\circ}C$ 이상의 온도에서 반응열처리를 했을 때 XRD 분석결과와 산소 조성 분석 결과로부터 반응의 완결성과 순도에서 최적 온도 조건임을 확인하였다. 온도를 $1,300^{\circ}C$로 증가시킬 경우 반응의 완결성에 큰 변화가 없는 반면 분말입자간의 목형성이 일어나 가소결 되는 것을 FE-SEM을 통해 관찰하였다. 또한 최적조건으로 제조된 Fe-TiC 복합분말의 입도분석과 FE-SEM/EDS 관찰/분석을 시행한 결과 평균 입도 0.6 ${\mu}m$의 미세한 Fe-TiC 복합분말 내에 Fe분말 주변과 내부에 나노크기의 TiC입자가 균일하게 분산되어 존재하는 것을 확인하였다.

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Effects of Ikgukwhan and Ikgukbowhawhan on the Production of Collagen and the Regeneration of Liver Cells Damaged by Bile Duct Ligation and Dimethylnitrosamine (익국환과 익국보화환의 실험적(實驗的) 간경변(肝硬變)에 대(對)한 효과(效果))

  • Bae Cheol-Ho;Kim Sung-Hwan;Kim Kang-San;Kang Byung-Ki
    • Herbal Formula Science
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    • v.6 no.1
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    • pp.119-139
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    • 1998
  • This study was to investigate the protective and effects of Ikgukwhan and Ikgukbowhawhan on the liver cirrhosis or fibrosis induced by prolonged bile duct ligation; a new experimental model for cirrhosis and the intraperitoneal injection of dimethylnitrosamine in the rat. The development of fibrosis or cirrhosis and its inhibition by the two prescriptions were examined by the chemical analysis of AST, ALT, and hydroxyproline. The results obtained were as follows. 1. The increase of serum asparate aminotransferase induced by bile ductligation was inhibited by the administration of Ikgukwhan and Ikgukbowhawn extract. 2. The increase of serum alanine aminotransferase induced by bile duct ligation was inhibited by the administration of Ikgukwhan and Ikgukbowhawhan extract. 3. The increase level of serum AST and ALT induced by the intraperitoneal injection of dimethylnitrosamine was inhibited by the administration of Ikgukwhan and Ikgukbowhawhan extract. 4. The increase level of hydroxyproline volume in the damaged liver tissues in the rat was decreased by the oral administration of Ikgukwhan and Ikgukbowhawhan extract. But there were no significant differences in the inhibition rate between the two experimental groups.

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Properties of Epoxy Modified PVC-sol Sealants (에폭시가 함유된 PVC졸 실란트의 물성)

  • Lee, Seung-Jin;Kim, Hyun-Kyo;Park, Hwan-Man;Cho, Won-Jei;Ha, Chang-Sik
    • Elastomers and Composites
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    • v.34 no.3
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    • pp.199-211
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    • 1999
  • In this work, the effects of the addition of epoxy on the properties of PVC-sol sealants were investigated. PVC-sol was plasticized with dioctyl phthalates(DOP). Two kinds of epoxy resins having different epoxy equivalent weight (E.E.W.) were used. It was found that the properties of the PVC-sol sealants were significantly affected by the contents and types of the added epoxy resins. The viscosity behaviors of the epoxy-modified sealants, in the case of epoxy A addition, the viscosity was decreased with increasing the epoxy contents, but In the case of $CaCO_3$ addition, the viscosity was increased with increasing the $CaCO_3$ contents. The viscosity of epoxy modified sealants aged at $45^{\circ}C$ waterbath was decreased with increasing epoxy contents, since the epoxy acted on the sealants as a stabilizer. The thermal stability of the PVC-sol sealants was slightly improved by adding epoxy. The tensile strength and elongation of sealants modified with epoxy A(two functionalities of epoxy) were increased with increasing the epoxy contents up to a certain epoxy contents but was decreased with further increasing the epoxy contents. In the case of $CaCO_3$ addition, the tensile strength of sealants were decreased with increasing the $CaCO_3$ contents. In view of the electrical properties, such as tan ${\delta}$($0.1{\pm}0.04$) and ${\epsilon}_r$($0.5{\pm}0.04$), it was found that the epoxy modified sealants were as good as insulators.

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Physical Properties of Chitosan Film made from Crab Shell (꽃게 껍질에서 분리제조한 키틴산 필름의 물성에 관한 연구)

  • Cho, Jeong-Suk;Han, Jeong-Jun;Lee, Cherl-Ho
    • Korean Journal of Food Science and Technology
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    • v.24 no.6
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    • pp.574-580
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    • 1992
  • Chitin was isolated from the residue of enzymatically hydrolyzed crab, Portunus trituberculatus, and further deacetylated by alkaline boiling to make chitosan. The physical properties of chitosan solution and its film forming properties were examined. The functional characteristics of chitosan film were compared to those of cellophane, polyvinyl chloride (PVC) and polyethylene (PE) films. The proximate chemical composition of chitin obtained from crab residue was 6.95% nitrogen, 0.3% crude ash and 4.57% moisture and the product yield was 12.8% based on a dry material basis. The degree of deacetylation of chitosan was $79{\sim}92%$ and $70{\sim}86%$ as determined by IR spectroscopy, and $70{\sim}86%$ as determined by colloid titration method each respectively. The chitosan at 1% acetic acid solution showed distinct pseudoplastic flow behavior. The flow behavior index and consistency index were 0.8886, 0.2084 $MPa{\cdot}s^n$ for 0.4% solution and 0.8498, 0.6190 $MPa{\cdot}s^n$ for 0.8% solution, respectively. The chitosan film had the highest tensile strength $(888 kg/cm^2)$ and water permeability $(100\;g/m^2{\cdot}24\;hrs)$ among the tested films, but relatively low elongation property (49%). It showed the similar tear strength (90kg/cm) and light permeability (87.7%) to other films tested in spite of the relatively high haze value (12.5%). As the thickness of chitosan film increased from 0.025 to 0.050 mm, the tensile strength of film decreased distictively, and the degree of elongation, tear strength, and water permeability of film also decreased slightly. Whereas the light permeability of film did not change and the haziness of film slightly increased by the increase of film thickness.

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Pervaporation Separation of Ethanol Aqueous Solution through Carbonate-type Polyurethane Membrane III. The Effect of Zwitterionic Group (카보네이트형 폴리우레탄막을 이용한 에탄올 수용액의 투과증발분리 III. 양쪽이온성기에 의한 영향)

  • Oh, Boo Keun;Lee, Young Moo;Noh, Si Tae
    • Applied Chemistry for Engineering
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    • v.3 no.4
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    • pp.605-613
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    • 1992
  • NCO-terminated prepolymers were synthesized by reacting carbonate-type polyol(PTMCG)($M_w=1,000$ and 2,000) with MDI and N-methyldiethanolamine, as a chain extender. Carbonate-type polyurethane containg zwitterionic group was prepared by reacting the prepolymer with 1,3-propane sultone. From the IR and NMR spectra of model reactions, it was known that the ionization occurred under the same condition. The structure of zwitterionic carbonate-type polyurethane(ZPU) therefore could be confirmed from the model reactions. Glass transition temperature(Tg) ranged between $-15{\sim}-30^{\circ}C$ from the thermal data. Tg was between $-15{\sim}-18^{\circ}C$ for a series of ZPU10 samples and between $-25{\sim}-26^{\circ}C$ for a series of ZPU20 polymers. Tensile strength increased with mole ratio of ionic content. On the contrary, elongation was rather dropped with mole ratio of ionic content. ZPU10-30 having better tensile strength and less elongation was selected as a membrane for the concentration of ethanol aqueous solution through pervaporation. To obtain the better selectivity, it was crosslinked with HMDI. In the swelling test, it showed the higher swelling degree at around 50wt% ethanol concentration due to the plastization effect of ethanol. To optimize the separation capacity, two operating factors-feed concentration and temperature-were considered. The overall separation capacity was as follows : separation factor, 2~83.2 ; the flux, $25.4{\sim}58.8g/m^2hr$.

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Evaluation of Feed Value and Fermentation Quality of New Wheat Cultivar, 'Taejoong' (밀 신품종 '태중'의 사료가치 및 발효품질 평가)

  • Song, Tae-Hwa;Kim, Kyeong-Hoon;Cheong, Young-Keun;Son, Jae-Han;Park, Jong-Chul;Oh, Young-Jin;Park, Jong-Ho;Kim, Yang-Kil;Kim, Kyong-Ho;Park, Tae-Il;Kim, Bo-Kyeong;Kang, Chon-Sik
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.37 no.1
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    • pp.61-67
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    • 2017
  • This experiment was conducted to obtain information of feed value and fermentative quality of wheat cultivar, 'Taejoong' to confirm availability as a whole crop silage. As a result, the heading date of 'Teajoong' is April 27, and plant height is longer than whole crop barley, 'Youngyang' or whole crop wheat, 'Cheongwoo', spike length are also large, fresh and dry matter yield are also high. In case of feed value, 'Taejoong' had higher crude protein content than whole crop barley, 'Youngyang' or whole crop wheat, 'Cheongwoo', lower NDF and ADF contents, and significantly higher digestible nutrient contents(p<0.05). In case of fermentation qulity, pH of 'Taejoong' was 4.2, and lactic acid content was lower than 'Cheongwoo' silage and significantly higher than 'Youngyang' silage(p<0.05). Acetic acid content was significantly lower than 'Youngyang' and 'Cheongwoo' silage(p<0.01), butyric acid content was significantly lower than that of 'Youngyang' silage (p<0.05). The final Flieg's score showed that 'Taejoong' silage was the best. Also income of 'Taejoong' improved than 'Youngyang' or 'Cheongwoo'. Therefore, 'Taejoong' is considered sufficiently available as whole crop for forage.

Effect of Shading Degrees on Yields and Nutritive Values of Forage in Forest-Grassland (차광정도가 임간초지 혼파초지의 식생 및 목초생산성에 미치는 영향)

  • Kim, Won Ho;Kim, Hyun Seup;Park, Hyung-Su;Jung, Jeong Sung;Choi, Ki-Choon
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.37 no.4
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    • pp.283-289
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    • 2017
  • The present study was carried out to explore the potential effect of shading degrees on yields and nutritive values of forage in forest-grassland. This experiment was conducted this study under different natural shading at National Institute of Animal Science, Cheonan province in Korea, for 2 years (from 2015 to 2016). This experiment was consisted of four different shading degrees, such as full sunlight (control, 10% below), 25% of shading, 35% of shading, 50% of shading. Pasture species used in this study were orchardgrass 'Kodiwin', perenial ryegrass 'Linn', tall fescue 'Purumi', kentuky bluegrass 'Kenblue', and white clover 'Ladino'. Botanical composition of orchardgrass was higher than that of perenial ryegrass, tall fescue and kentuky bluegrass. Dry matter (DM) yields of forage decreased as increasing shading degrees. DM yields of forage significantly decreased as increasing shading degrees and lots of cutting times under increasing shading degrees decreased DM yields of forage. The content of crude protein increased as increasing shading degrees and the contents of acid detergent fiber (ADF), neutral detergent fiber (NDF), the activity of total digestible nutrient (TDN) and in-vitro digestibility (IVD), and relative feed value (RFV) were similar in control and different shading. This study suggests that orchardgrass is major component for forest-grassland and establishment of orchardgrass can be improved by increasing shading degrees.

Studies on the Cultivation Technique and Evaluation of Forage Resources for a New Oil Crop Chufa(Cyperus esculentus L.) (새로운 유지작물 기름골의 재배기술과 사료가치)

  • Sung, Byung-Ryeol;Kim, Jong-Keun;Kim, Weon-Ho;Park, Hee-Woon;Bang, Jin-Ki;Song, Jin
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.24 no.2
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    • pp.163-170
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    • 2004
  • A new oil crop chufa(Cyperus esculentus var. sativus) was studied to evaluate the yield potential of tuber and productivity of leaf as a new forage crop resources. Response to nitrogen fertilizer was not clear, showing low yield over 10kg/l0a of nitrogen application. Tuber yield was higher at 50cm $\times$ 15cm and 50cm$\times$20cm of planting population of tuber. Planting at early May showed high tuber yield, and sprouting tuber planting could not increased the tuber yield. The plant height of Chufa is 126cm, and the number of tiller per $\m^2$ are 671. It is moderate to lodging, but susceptable according to the amount of field products. Fresh forage and dry matter yield of above ground of chufa were 2,135kg/10a, and 590kg/l0a, respectively. The contents of crude protein, ether extract, fiber, ash, and acid detergent fiber are 24.8%, 8.1%, 38%, 64.4%, 52.8%, and 55.9%, respectively. It was considered that the nutritive value of chufa leaf in maturing stage was so good as rice straw.

Physiology and Nutrition of Pasture Plants (목초의 생리 및 영양)

  • 이주삼
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.12 no.3
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    • pp.64-129
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    • 1992
  • 최근 초지중심 사양형태의 증가와 초지면적의 확대에 따라 단순한 사료로서가 아니라 영양가치가 높고 기호성이 높은 목초생산이 요구되고 있다. 그러나, 고위생산을 위해 다량으로 사용된 질소질비료에 의하여 질산태 중독 등의 문제가 야기되고 있어 목초의 생리 및 영양에 관한 연구가 필요하게 되었다. 사료성분 혹은 영양가치에 대한 연구는 이미 일찍부터 다루어져 왔으나, 주로 야초류, 청예작물 및 농가부산물 등의 일반성분 특히, 조단백질과 조섬유함량의 연구가 주가 되었고 다년생 목초류에 대한 연구는 1975년경부터 본격화 되기 시작하였다. 그동안 한국초지학회지와 축산학회지($1972\sim1991$)에 게재된 총 151편의 생리 및 영양에 관한 연구 중에서 다년생 목초류를 취급한 것은 불과 63편에 머물고 있다. 이 분야의 연구는 각종 목초 사료작물에 대한 재배조건과 생육단계에 따른 생리생태학적 연구와 사료성분, 소화율 및 가소화양분 함량의 일반적인 변화, 경향을 검토하여 사료 가치 평가를 위한 기준으로 삼았다. 그러나 다년생 목초류는 물론 사료 작물에 있어서 육종 생리분야의 연구는 매우 미흡한 상태로써 단지 발아, 생육, 저장탄수화물 및 유독성분 등 단편적인 연구만이 행해지고 있을 뿐이다. 또한 사료 성분이 가축의 기호성에 미치는 영향을 구명하기 위한 연구는 거의 이루어지고 있지 않으므로 금후 탄수화물과 미량 요소에 대한 자세한 연구 검토가 필요하다고 생각된다. 특히 목초와 사료작물의 화학적인 조성과 가축의 생리에 관련한 여러가지 문제들도 앞으로 보다 깊이 연구되어야 할 과제라고 생각된다.권을 잡기 위해 10년지기였던 IBM과 MS사는 각각 OS/2와 윈도즈를 내세우고 양보할 수 없는 힘겨루기에 들어갔다. 또 이들 양사는 펜컴퓨터,멀티미디어등 차세대제품의 운영체제 시장을 둘러싸고 일찍부터 격전에 들어갔으며 IBM과 MS사의 혼전을 틈타 썬마이크로시스템을 필두로한 워크스테이션 업체 및 유닉스진영까지 고성능 PC시장을 겨냥한 OS를 속속 개발, 90년대의 OS 전쟁은 한치 앞을 내다볼 수 없는 안개국면으로 접어들고 있다. DOS에서 32비트시대,펜컴퓨터, 멀티미디어에 이르는 차세대제품을 둘러싼 업계의 OS 쟁탈전을 통해 OS의 발전동향과 미래를 전망해 본다. results in the large change of the objective function, the sum of squares of deviations of the observed and computed groundwater levels. 본 논문에서는 가파른 산사면에서 산사태의 발생을 예측하기 위한 수문학적 인 지하수 흐름 모델을 개발하였다. 이 모델은 물리적인 개념에 기본하였으며, Lumped-parameter를 이용하였다. 개발된 지하수 흐름 모델은 두 모델을 조합하여 구성되어 있으며, 비포화대 흐름을 위해서는 수정된 abcd 모델을, 포화대 흐름에 대해서는 시간 지체 효과를 고려할 수 있는 선형 저수지 모델을 이용하였다. 지하수 흐름 모델은 토층의 두께, 산사면의 경사각, 포화투수계수, 잠재 증발산 량과 같은 불확실한 상수들과 a, b, c, 그리고 K와 같은 자유모델변수들을 가진다. 자유모델변수들은 유입-유출 자료들로부터 평가할 수

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