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Variable effects of biochar application to soils on nitrification-mediated N<sub>2</sub>O emissions
Yoo, Gayoung,Lee, Yong Oon,Won, Tae Jin,Hyun, Jun Ge,Ding, Weixin Elsevier 2018 Science of the Total Environment Vol.626 No.-
<P><B>Abstract</B></P> <P>Although a meta-analysis on biochar's effects on N<SUB>2</SUB>O emission reported an overall reduction in N<SUB>2</SUB>O emission by adding biochar to the soils, there are still variations in the changes in N<SUB>2</SUB>O emission, especially from field results. The objectives of this study are 1) to compare the effects of biochar addition on N<SUB>2</SUB>O emission between three agricultural upland field experiments, where soil water status was dry favoring nitrification and 2) to identify main factors explaining biochar's variable effects on N<SUB>2</SUB>O emission. Three field experiments were conducted: Exp A in the cultivated grassland treated with rice husk biochar at 2 ton ha<SUP>−1</SUP> + urea (CHAR) and with urea only (CON); Exp B in the cabbage field with CHAR and CON treatments; and Exp C in the pepper field with CHAR, CON, and CHAR + DCD (dicyandiamide, nitrification inhibitor) treatments. In Exp A and C, cumulative N<SUB>2</SUB>O emissions significantly increased by 82.5% and 55.8% in the CHAR than CON treatments, respectively, while in Exp B, there was no difference in cumulative N<SUB>2</SUB>O emission between the CHAR and CON. Based on results from using nitrification inhibitor and soil % water filled pore space (WFPS), we assumed that the main N<SUB>2</SUB>O production mechanism was nitrification. Our results suggest that soil water status right after urea application is the primary determinant of different effects of biochar on N<SUB>2</SUB>O emission in addition to soil C status and biochar's adsorption. Principal component analysis using the 25 compiled data also supported our results. This study identified the specific field conditions under which biochar could have stimulating effects on N<SUB>2</SUB>O emission. Mitigation potential of biochar application should be reconsidered if biochar and urea were amended to dry soils with low C contents.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N<SUB>2</SUB>O emissions were increased or not changed when both biochar and urea were applied to dry soils with low C content. </LI> <LI> Soil water status right after urea and biochar application was the primary determinant to predict the effect of biochar on N<SUB>2</SUB>O emissions, together with soil C status and biochar's adsorptive capacity. </LI> <LI> Our study is unique in that we obtained the results from multiple field experiments covering the whole cropping periods. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
김용진(Yong Jin Kim),박성환(Sung Hwan Park),주대현(Dae Hyun Joo),이한일(Han Il Lee),유용운(Young Oon Yoo),박기호(Ki Ho Park),이진우(Jin Woo Lee),김양일(Yang Il Kim) 대한소화기학회 1997 대한소화기학회지 Vol.29 No.2
The authors experienced a case of diffuse gastric polyposis with focal malignant transformation. A 61-year-old male visited this hospital because of epigastric pain. The gastrofibroscopic examination showed numerous polyps in entero-gastric mucosa mainly in the antrum and confirmed malignant change from one of the largest polyps in the antrum in the preious gastrofibroscopic examination dane six years ago. There was no family history of gastrointestinal polyps and the colon of this patient was intact. The total numbers of polyps was numerous, about 300, or more in the gastrectomized specimen. The size of polyps are variable, from less than 1mm to over 10mm, the largest one being 1,2cm * 0.5cm, but most of them were less than 0.3cm. The polyps were seattered in the fundus, cardia, body and antral portion of the stomach, but located mainly in the antrum, about 80% or more. All of the polyps were sessile. Microscopically, focal dysplastic changes and rnalignant changes were found in the superficial layer of the mucosa, which were located in the antrum. The remsining mucosa showed chronic atrophic gastritis associated with intestinal metaplasia, The hyperplastic gastric polyps comprised of appoximatcly 75% of all gastric epitheiial polyps. A coincident gastric carcinoma was repotted in 1.7%-2% patients with hyperplsatic polyps, Carcinoma lesions could be classified as type IIa early gastric cancer. At operation, there were no enlarged regional lymph nodes, and the other intraaMominal organs were intact grossly. There were no metastatic tumors in 35 dissected regional lymph nodes. The D2, total gastrectamy, Roux-En-Y, was performed, and the patient recovered uneventually (Korean J Gastroenterol 1997; 29:274 - 278)
Insecticide Resistance in the Tobacco Cutworm, Spodoptera litura(Fabricius) (Lepidoptera: Noctuidae)
Kim, Yong-Gyun,Cho, Jum-Rae,Lee, Joon-Ik,Kang, Sung-Young,Han, Sang-Chan,Hong, Ki-Jung,Kim, Hong-Sun,Yoo, Jae-Ki,Lee, Jeang-Oon Korean Society of Applied Entomology 1998 Journal of Asia-Pacific Entomology Vol.1 No.1
Field populations of the tobacco cutworm, Spodoptera litura(Fabricius), showed resistance to commonly used insecticides. Development of resistance in the field populations to pyrethroids (cypermethrin, deltamethrin, ethofenprox, ethofenprox+PAP and fenvalerate) ranged from 100- to 2,700-fold, showing the highest resistance level to deltamethrin. Resistance to organophosphorus in secticides(chlorpyrifos, chlorpyrifos-methyl, EPN and pyraclofos) ranged from 2- to 32-fold with the highest level to chlorpyrifos. Resistance to carbamates (carbaryl and methomyl) ranged from 4- to 80-fold with the higher level to carbaryl. Detoxifying enzyme assays revealed that esterase and glutathione S-transferase activities were varied from 2- to 6-fold among the field populations. In addition, the bimolecular rate constants for inhibition of acetylcholinesterase by dichlorvos, eserine and monocrotophos showed 1.5-, 4.5- and 4.3-fold differences, respectively, between two different field populations. These results indicated that the broad spectrum of insecticide resistance observed in the filed populations was due to multiple resistance mechanisms, including increased detoxification of these insecticides and insensitive acetylcholinesterase.
Time-Domain Dynamic Simulation of a Wind Turbine Including Yaw Motion for Power Prediction
Kim, Kwansu,Lim, Changhee,Oh, Yong-Oon,Kwon, Ilhan,Yoo, Neungsoo,Paek, Insu Korean Society for Precision Engineering 2014 International Journal of Precision Engineering and Vol.15 No.10
A new wind turbine simulation tool for a time-domain dynamic simulation was developed in this study. The tool consists of models of aerodynamics, drive train, generator, actuators, and controllers for pitch and yaw controls. For the wind turbine model, the NREL 5MW reference wind turbine was used. Using measured data, the developed tool was applied to predict annual energy production from the wind turbine at four different sites in a complex terrain of Korea. The results were compared with those predicted by a commercial frequency-domain program widely used to predict the annual energy production from a wind turbine. Without a yaw control, the predictions from the proposed tool were close to those from the commercial wind farm design program. Also, from simulations with and without yaw controls, the differences in power predictions were quantified. The results of this study suggest that the power production from a wind turbine can be predicted by the proposed time-domain wind turbine simulation tool with a proper yaw algorithm which is not available in commercial frequency-domain programs. Further research is needed to experimentally validate the simulation results with yaw algorithm.
아민 추출제에 의한 유기산의 반응추출 Ⅱ - Lewis Stirred Cell 추출기를 이용한 반응추출제에 의한 유기산의 물질이동 -
류운형,이한섭,유철휘,김용렬,강안수 ( Oon Hyung Ryu,Han Seob Lee,Chul Hwi Yoo,Yong Yeul Kim,An Soo Kang ) 한국공업화학회 1995 공업화학 Vol.6 No.6
Lewis식 교반추출장치에서 물질전달계수에 미치는 교반속도의 영향 및 무차원군의 관계를 구명하였다. Lewis식 교반추출장치에서 교반속도가 커질수록 유기산의 수용액측 물질전달계수는 증가하였고 추출도 또한 증가하였다. 그리고 0.05M 메타아크릴산을 Trioctylamine으로 추출하는 경우에 최적조건은 교반속도 200rpm, 추출시간 50분이었으며, 이때 물질전달계수는 5.52×10^(-5)m/s이었다. 또한 추출속도에 대한 무차원 상관관계를 얻었으며 그 결과는 본 실험에 사용한 유기산 중에서 아크릴산의 경우 Sh=(Re·Sc)^(0.97), 메타아크릴산의 경우 Sh=(Re·Sc)^(0.68)에 각각 비례하였다. 이때 이들의 상관식은 15% 이내의 오차 범위에서 일치하였다. The mass transfer coefficient of organic acid in aqueous phase and the degree of extraction were increased with increasing agitation speed in Lewis stirred cell extraction unit. The optimum conditions of agitation speed and the extraction time were 200rpm and 50min respectively for the case of 0.05M methacrylic acid extraction with trioctylamine, and in these conditions, the mass transfer coefficient was 5.52×10^(-5)m/s. Correlations of dimensionless group for extraction rate were obtained, such that Sh is proportional to (Re·Sc)^(0.97) in acrylic acid, and Sh is proportional to (Re·Sc)^(0.68) in methacrylic acid. Also, calculated values by using these correlation eqations were consistent within 15% error range with experimental ones.
아민 추출제에 의한 유기산의 반응추출 (Ⅰ) ( 유기산의 반응추출시 추출도에 미치는 추출제 및 용매의 영향에 관한 연구 )
류운형,이한섭,유철휘,김용렬,강안수 ( Oon Hyung Ryu,Han Seob Lee,Chul Hwi Yoo,Yong Yeul Kim,An Soo Kang ) 한국공업화학회 1996 공업화학 Vol.7 No.1
평형 추출장치를 사용하여 유기산의 물리추출과 반응추출에서 추출도에 미치는 추출제의 종류와 농도, 용매의 영향을 조사하였다. 사용된 유기산은 아크릴산과 메타크릴산이었고, 추출제로는 n-octylamine(OA)과 di-n-octylamine(DOA), tri-n-octylamine(TOA) 및 tri-octylmetyl ammonium chloride(TOMAC; Aliquat 336)을 사용하였다. 실험결과 반응추출에서 추출도는 물리추출의 경우보다 2∼9배 정도 증가 되었으며, 유기산의 추출도에 미치는 추출제의 영향은 OA, TOMAC, DOA 및 TOA의 순서로 추출도가 증가하였으며, 또한 추출제의 농도가 증가할수록 추출도가 증가하였다. 용매의 영향은 종래의 용매의 유전상수보다는 용해도인자에 의한 용매선택 방법이 신뢰성이 있었고, 용질과 용매의 용해도인자의 차이가 작을수록 추출도가 증가하여 케로진, 크실렌, 클로로포롬, MIBK 및 n-BAc의 순서로 좋아졌다. In physical and reactive extraction system using equilibrium extraction equipment, the effects of extractants, concentration of extractant, and solvent on the degree of extraction were investigated. The organic acids used were acrylic acid and metacrylic acid. Extractants were n-octylamine(OA), di-n-octylamine(DOA), tri-n-octylamine(TOA) and tri-octylmetyl ammonium chloride(TOMAC; Aliquat 336). We found that the degree of extraction for reactive extraction was 2∼9 times than that for physical extraction and that effect of extractants on the degree of extraction of organic acid was the order of OA<TOMAC<DOA<TOA. And the degree of extraction was increased with increasing the concentration of extractants. In solvent effect, solubility parameter was more effective than dielectric constant of solvent, and the degree of extraction increased as the difference of solubility parameter of solvent and solute decreased, therefore the order was kerosine<xylene<chloroform<MIBK<n-BAc.