• Journal of Plant Biology
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• 제4권2호
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• pp.51-61
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• 1961

In order to detect the way of absorption and metaboism of the urea it is sprayed on the surface of the leaves of sunflower. The sunflowers used in this study are grown in different conditions such that the one in nittogen aboundant and the other in nitrogen deficient soil, respectively. The urea-N, ammonia-N, amide-N, and 80% alcohol soluble-N in the leaves were quantitatively determined. All of the nitrogenous components measured are generally tended to increased with rising the concentration of urea except only amide-N at 24 hours after sprayed, and these were highly significances. It seemed that hydrolizing of urea into ammonia and carbon dixide and the assimilation of ammonia into other organic nitrogenous constituents were rapid in the young leaves than in the mature. It is interest that the amide content, in the young leaves and nitrogen defieient one were enhanced with the increasing concentration of urea, although in the mature leaves it did not show any change in the urea treatment. It is presumed that the assimilation rate of ammonia and the urease activity were lower in the matture leaves than in the young and nitrogen deficient leaves. No significance at 5% level showed all of the nitrogenous components except total nitrogen between nitrogen abundant and deficent leaves. Urea content was a high peak at first 12 hours, ammonia at 48 hours, and amide and alcohol soluble nitrogen at 96 hours, whence decrease4d the content of these constituents gradually. The total nitrogen content is not incrased obviously by only one time of urea spray in this study. When the concentration of urea was relatively high there appeared the wilting spots on t도 edge of leaves. As a whole, it seemed that sprayed urea was rapidly absorbed and taken part in nitrogen metabolism within relatively short period.

• 한국대기환경학회지
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• 제6권2호
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• pp.147-154
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• 1990

A sensitive method for the determination of total selenium in aerosol particles is described. The method involves dissolution of aerosol particles by $HNO_3-HClO_4$ mixed acids, pre-reduction of Se (VI) to Se (IV) by boiling hydrochloric acid, and hydride generation followed by atomic absorption detection. Dissolved Se (IV) in 4M hydrochloric acid is reacted with $NaBH_4$ to form $H_2Se$, which is subsequently collected in an U-tube cooled in liquid nitrogen. Upon the completion of $H_2Se$ generation, the collected $H_2Se$ is rapidly vaporized into a quartz cuvette burner by removing the U-tube from liquid nitrogen, atomized, and then detected by an atomic absorption spectrophotometer. The absolute sensitivity of the method is 0.49 ng/0.0044 Abs. The accuracy of the method evaluated by analyzing standard reference materials for urban aerosol is better than 10%. Analytical results for urban and rural aerosol particles are reported.

• Journal of Plant Biology
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• 제24권1호
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• pp.13-19
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• 1981

Ammonium citrate와 ammonium succinate가 고려인삼(Panax ginseng C. A. Meyer) 배양세포의 생육 및 질소성분의 흡수에 미치는 영향을 조사하기 위하여 Murashige and Skoog 배지에서 ammonium nitrate 대신에 농도를 달리하여 ammonium citrate와 ammonium succinate를 첨가한 MS배지에 인삼 callus를 액체 진탕배양하여 다음과 같은 결론을 얻었다. Ammonium citrate 10mM과 ammonium succinate 10mM을 첨가한 배양기에서 생육량, NO$_3$-N 흡수량 및 전질소량이 control보다 많았고, NH$_4$-N 흡수량은 control과 같았다. 또한 각각 5mM씩 첨가한 경우에는 거의 모두 control과 별 차이가 없었다. 결론적으로 ammonium citrate 10mM과 ammonium succinate 10mM첨가한 배양기에서는 NO$_3$-N 등의 흡수를 촉진하여 배양세포의 대사를 촉진시켜 생육량을 증가시키는 것으로 생각된다. 그리하여 ammonium citrate 또는 ammonium succinate의 농도를 조절 공급하면 인삼 배양세포의 증식을 촉진시킬 수 있다고 사료된다.

• 생물환경조절학회지
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• 제3권2호
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• pp.136-144
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• 1994

A long- time aeration method was developed for purification of animal wastewater. Under repeated aereations of 4 hours on and 4 hours off, the higher removal rates were obtained which were in average of 99%, 96%, 92% and 50% for BOD, SS, total nitrogen and phosporous, respectively. In detail, the measured BOD concentrations of the influent and effluent were 2,700ppm and 40ppm while the SS concentrations in the primary chamber and of the effluent were about 3,000 and 110 ppm, respectively. Zeolite and activated carbon, applied for removing the nitrogen and phosphorous, showed a good absorption, especially zeolite for NH$_4$-N and activated carbon for NO$_3$-N and PO$_4$-P. The treatment cost per head by this method amounts to 1,923 won and it comes to 1.6% in the whole production cost. Therefore, this method is economically available with the half cost of the conventional activated sludge process.

• The Korean Journal of Ecology
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• 제15권3호
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• pp.297-309
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• 1992

The growth of digitaria adscendens and eleusine indica, annual weeds common in japan, was experimentally analyzed under varying untrient conditions. compared with e. indica, d. adscendensshowed a higher the two under high nitrogen availability. Higher net assimilation rate(nar) in d. adscendens than e. india was responsible for high RGR in D. adscendens under the low nitrogen availability. The different of NAR in the two species was induced not by leaf nitrogen content but by nitrogen use efficiency. Under unfertilized conditions nitrogen uptake rate(nur) was greater in d. adscendens than e. indica. Specific absorption rate in two species was similar, but root mass was greater in d. adscendens than e. indica.d. adscendens allocated more dry matter to roots than e. india earlier stage of seedlings. The contributed to higher rot mass and in turn resulted in higher nur in d. adscendens than that in e. india. It is concluuded that the larger allocation of dry matter to roots at early seedling stage in d. adscendens plays an important role in obtaining nitrogen for the continuation of growth under low nitrogen availability.

• 한국환경복원기술학회지
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• 제23권3호
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• pp.63-79
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• 2020

The present study was to investigate the growth response and nutrient absorption in three willow species (Salix gracilistyla, S. koreensis and S. chaenomeloides) treated with nitrogen source (NH₄⁺:NO₃^- rate; 200:0, 150:50, 100:100, 50:150, 200:0) for a period of 90days. The height, dry weight and chlorophyll contents of three species of willows were found to be highest at 50:150 (NH₄⁺:NO₃^-) treatment. NO₃^--N was more effective than NH₄⁺-N in the early growth of three species of willows. The increase in percentage of NO₃^--N handling, T-N, NO₃^--N in plant tissue increased. The analysis of C, N and mineral content in various parts revealed that the amounts of C, N, K, Ca and Mg were higher in leaves than those in the stems and the roots. However, the amount of NO₃^--N and P were higher in roots than those in the leaves and the stems. Salix koreensis was excellent, followed by S. chaenomeloides and S. gracilistyla in absorption of nitrate nitrogen. Higher percentage of NO₃^--N, the amounts of T-N, NO₃^--N, P₂O₅, K, Na, Ca, and pH in soil were decreased.

• 한국물환경학회지
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• 제26권4호
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• pp.707-712
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• 2010

Nitrogen-doped $TiO_2$ particles have been successfully prepared using titanium tetraisopropoxide as the Ti source and urea as the nitrogen source. As-prepared nitrogen-doped $TiO_2$ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller method (BET) and ultraviolet-visible light (UV-vis) absorption spectra techniques. Photocatalytic degradation of Methylene Blue (MB) has been carried out in both solar light (UV-vis) and the visible region (${\lambda}=420nm$). Nitrogen-doped $TiO_2$ exhibits higher activity than the commercial $TiO_2$ photocalyst, particularly under visible-light irradiation because bandgap of nitrogen-doped $TiO_2$ becomes remarkably decreased.

• 대한원격탐사학회지
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• 제39권5_1호
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• pp.551-561
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• 2023

본 연구에서는 Pandora spectrometer system의 태양 직달광 관측 자료로부터 차등흡수분광법(differential optical absorption spectroscopy, DOAS)을 이용하여 포름알데히드(formaldehyde)의 경사칼럼농도(slant column density, SCD)를 산출할 때 스펙트럼 피팅(spectrum fitting) 파장 구간 및 흡수단면적이 산출에 미치는 영향을 조사하였다. 2022년 10월 12일에서 31일까지 서울 연세대학교에서 관측한 Pandora Level 1 자료를 사용하였다. The second Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI-2)에서 사용하는 스펙트럼 피팅 파장 구간을 포함한 8가지 범위 및 흡수단면적 구성 7종을 기반으로 포름알데히드 칼럼농도를 산출하였다. 스펙트럼 피팅 파장 구간은 8가지 범위 중 336.5-359.0 nm 구간에서 피팅 후 잔여 신호와 포름알데히드 산출 오차가 최소로 확인되었다. 흡수단면적 구성 7종 중 CINDI-2 캠페인에서 사용하는 흡수단면적에 이산화질소 흡수단면적(220 K)을 추가하여 사용한 경우에 피팅 후 잔여 신호와 포름알데히드 산출 오차가 가장 작았으며 포름알데히드 농도가 안정적으로 산출되었다. 산출 정확도가 가장 높은 경우의 평균 포름알데히드 경사칼럼농도와 그 외 조건들에서 산출된 값들은 최소 4%에서 최대 40%까지 차이를 보였다.

• 한국작물학회지
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• 제27권3호
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• pp.206-217
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• 1982

지대별 이앙기의 차이가 수도의 지엽과 인각의 양분흡수이용에 미치는 영향을 분석 조사하였던 바 다음과 같은 결과를 얻었다. 1. 출수지연은 지엽중 전질소함유율을 높이고 규산의 흡수를 저해하여 불임을 야기 시키는데 그 경향은 만식과 고지대일수록 뚜렷하다. 2. 지엽에 축적된 전질소함유율과 규산함유의 다소는 수량을 좌우하는 유의적인 상관관계를 이룬다. 3. 만식과 등숙이 불량한 인각일수록 전질소함유율은 높으나 규산의 흡수는 상대적으로 낮아지는 상관관계를 나타낸다. 4. 인각의 무기성분함유율은 출수후 등숙기온에 영향을 받는데 등숙기온이 높을수록 인각의 인산, 가리, 칼슘, 규산의 함유율은 증가하나 전질소 함유율은 낮아져 인각의 무기성분조성이 불임과 밀접한 관계가 있음을 암시하여 준다.

• 한국산림과학회지
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• 제77권4호
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• pp.361-370
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• 1988

본(本) 연구(硏究)는 해송묘목(海松苗木)에 모래밭버섯(Pisolithus tinctorius) 균(菌)을 인공(人工) 접종(接種)한 후(後) 두개의 혼합토(混合土)와 6개의 질소수준(窒素水準)으로 처리(處理)된 실생묘(實生苗)의 생장(生長)과 균근(菌根) 형성(形成) 그리고 양료흡수관계(養料吸收關係)를 추정(推定)키 위(爲)해 실시(實施)되었다. 1) $50-150{\mu}g/ml$ N로 시비(施肥)된 vermiculite에서 자란 실험묘(實生苗)는 pinnate type과 cluster-like type이 잘 발달(發達)하였으나, 사질괴토(砂質壞土)는 monopodial, cluster-like type 그리고 pinnate type 이 발달(發達)하였다. 2) 균근형성(菌根形成)의 과정시비수준(適正施肥水準)은 50 또는 $150{\mu}g/ml$로 균근형성(菌根形成)이 각각(各各) $86.4({\pm}3.14)%$%와 $73.0({\pm}7.21)%$였다. 그러나 질소수준(窒素水準)이 증가(增加)하면 균근형성(菌根形成)이 감소(減少)하였다. 3) $450{\mu}g/ml$N로 시비(施肥)된 실생묘(實生苗)는 순(純) 회수율(同化率)(NAR)과 개체생장율(個體生長率)(CGR)이 생장초기(生長初期)에는 감소(減少)하였으나 질소시비(窒素施肥)가 멈춘 8월(月) 이후(以後)에는 다시 증가(增加)하였다. 4) 실생묘(實生苗)의 무기양료(無機養料) 흡수(吸收)는 질괴토(砂質壞土) 및 무접종구(無接種區)에 비해 vermiculite와 균근처리구(菌根處理區)에서 증가(增加)하였다. 그리고 회수율(回收率)은 $350{\mu}g/ml$ 질소수준(窒素水準)까지는 질소시비(窒素施肥) 증가(增加)에 따라 점진적(漸進的)으로 증가(增加)하였으나 $450{\mu}g/ml$ 질소수준(窒素水準)에서는 도리어 흡수(吸收)가 제한(制限)되었다.