• 한국환경농학회지
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• 제37권3호
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• pp.172-178
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• 2018

BACKGROUND: Composted animal manure applied to the arable soil for improving soil quality and enhancing crop productivity causes greenhouse gas emissions such as nitrous oxide ($N_2O$) by processes of nitrification and denitrification. However, little studies have been conducted on determining effect of application ratio of composted animal manure on $N_2O$ emission rate and its annual emission pattern from upland soil in South Korea. Therefore, this study was conducted to determine $N_2O$ emission rate and its annual emission pattern from upland soil supporting for sweet potato. METHODS AND RESULTS: Composted animal manure was applied at the ratio of 0, 10, and 20 Mg/ha to an upland soil supporting for sweet potato (Ipomoea batatas). Nitrous oxide emission was examined during growing season and non-growing season from May 2016 through May 2017. Daily $N_2O$ fluxes showed peaks right after applications of composted animal manure and inorganic nitrogen fertilizer. Precipitation and soil water content affected daily $N_2O$ flux during non-growing season. Especially, $N_2O$ flux was strongly associated with water filled pore space (WFPS). We assumed that the majority of $N_2O$ measured during growing season of sweet potato was produced from nitrification and subsequent denitrification. Annual cumulative $N_2O$ emission rate significantly increased with increasing application ratio of composted animal manure. It increased to 12.0 kg/ha/yr from 8.73 kg/ha/yr at control with 10 Mg/ha of composted animal manure and to 14.0 kg/ha/yr of $N_2O$ emission with 20 Mg/ha of the manure. CONCLUSION: To reduce $N_2O$ emission from arable soil, further research on developing management strategy associated with use of the composted animal manure and soil moisture is needed.

• 대한환경공학회지
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• 제27권1호
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• pp.59-66
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• 2005

[ $TiO_2$ ]박막은 DC 마그네트론 스퍼터링법을 이용하여 다양한 스퍼터링 파라미터(전력 $0.6{\sim}5.2\;kw$, 기판온도 실온${\sim}350^{\circ}C$, 산소량 $0{\sim}50\;sccm$($O_2+Ar$ 90 sccm, 압력은 약 1 mtorr))를 통하여 증착되었다. TiO-N박막도 가스의 유량비를 제외하고는 $TiO_2$박막과 같은 스퍼터링 조건하에서 증착되었다. 이러한 스퍼터링 파라미터에서 증착된 박막의 전기적 특성을 분석하기 위하여 시트저항을 측정하였고, 박막의 두께(${\alpha}$-step), 표면 거칠기(AFM), 형성 조직(FE-SEM, XRD)을 분석하여 최적 스퍼터링 파라미터를 도출하였다. 최적 스퍼터링 파라미터에서 제조된($TiO_2$, TiO-N)박막을 이용하여 광활성도를 평가하기 위하여 VOCs물질 중 toluene, 반응성 염료인 Suncion Yellow를 대상 물질로 선정하여 적용성 연구를 수행하였다. 실험에서 광촉매 박막은 적용물질에 대해서 광활성을 양호하게 보였으며, 특히 TiO-N광촉매 박막은 가시광 영역에서도 최대 33%의 톨루엔(5 ppm) 제거 효율을 나타내었다.

• 한국대기환경학회지
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• 제20권6호
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• pp.749-758
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• 2004

Nitrous oxide ($N_2$O) has been known as an important trace gas due to the greenhouse gas and the major source of stratospheric oxide of nitrogen (NO). Soil is the major source of $N_2$O in nature. The physicochemical characteristics of soils affect the emission of $N_2$O from soil. These physicochemical parameters are soil moisture, soil temperature, and soil N content. Since these parameters are correlated to the flux of $N_2$O from soil individually and compositely, there still remain many unknowns in the mechanism to produce $N_2$O in soil and the roles of such physicochemical parameters which affect the soil $N_2$O emission. Soil $N_2$O fluxes were measured at different levels in water filled pore space (WFPS), soil temperature and soil N contents from the same amounts of soils which were sampled from agriculturally managed upland field in a depth of ～30 cm at Kunsan. The soil $N_2$O flux measurements were conducted in a laboratory with a closed flux chamber system. The optimum soil moisture and soil temperature were observed at 60% of WFPS and ～13$^{\circ}C$. The soil $N_2$O flux increased as soil N contents increases during the whole experimental hours (up to 48 hours). However, average $N_2$O flux decreased after ～30 hours when organic carbon was mixed with nitrogen in the sample soils. It is suggested that organic carbon could be important for the emission of $N_2$O, and that the ratio of N to C needs to be identified in the process of $N_2$O soil emission.

• 한국자기학회지
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• 제13권1호
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• pp.15-20
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• 2003

Cu 금속 미분말은 확산속도가 CuO 보다 CuO 보다 빠르고 소결시 입자성장을 촉진시키기 때문에 기본조성 (N $i_{0.204}$C $u_{0.204}$Z $n_{0.612}$ $O_{1.02}$)F $e_{1.98}$ $O_{2.98}$에 들어가는 CuO대신 Cu/CuO의 비를 변화시켜 가면서 Cu가 ferrite에 미치는 영향을 조사하였다. Cu를 CuO 대신 치환함으로써 90$0^{\circ}C$에서 완전한 Spinel구조를 가짐을 XRD pattern을 통하여 확인하였고, Cu/CuO 비가 60%일 때가 투자율 1100, Ms 87 emu/g의 최적조건을 얻었다. Cu는 소결시 확산속도를 증가시켜 입자성장에 영향을 주었으며, CuO대신 Cu의 치환은 저온에서 투자율이 개선됨을 확인하고 소결온도를 3$0^{\circ}C$이상 낮출 수 있었다. 소결이 끝난 후에는 CuO와 같은 거동을 하는 것으로 확인되었다.

• 한국세라믹학회지
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• 제29권4호
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• pp.328-334
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• 1992

TiO2 sols were prepared by hydrolysis and polymerization of titanium tetra-isopropoxide (TTIP) in the presence of diethanolamine (DEA). The optimal mole ratio of water to TTIP is 2 and the concentration of the TiO2 sol 0.7 M. Golden TiN films without cracks were obtained by dipping Si(110) wafers into the TiO2 sol and followed by nitridation in NH3 at 1100$^{\circ}C$ for 5 h. The TiN films were studied by an optical microscope, DTA, TGA and X-ray analysis.

• 한국전기전자재료학회논문지
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• 제33권6호
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• pp.433-438
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• 2020

To enhance the tunneling electroresistance (TER) ratio of a ferroelectric tunnel junction (FTJ) device using Al-doped HfO₂ thin films, a thin insulating layer was prepared on a TiN bottom electrode, for which TiN was preliminarily treated at various temperatures in O₂ ambient. The composition and thickness of the inserted insulating layer were optimized at 600℃ and 50 Torr, and the FTJ showed a high TER ratio of 430. During the heat treatments, a titanium oxide layer formed on the surface of TiN, that suppressed oxygen vacancy generation in the ferroelectric thin film. It was found that the fabricated FTJ device exhibits two distinct resistance states with higher tunneling currents by properly heat-treating the TiN bottom electrode of the HfO₂-based FTJ devices in O₂ ambient.

• 한국세라믹학회지
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• 제22권5호
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• pp.35-42
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• 1985

$eta$-Sialon powders were prepared by reduction-nitridation from mixture of Wando pyrophyllite and graphite as a reducing agent at 135$0^{\circ}C$ in 80% $N_2$-20% $H_2$ atmosphere. As the reaction products $Si_2ON_2$, $\beta$-$Si_3N_4$ a--$Si_3N_4$ and $\beta$-SiC were observed. Additive agents of MgO, CaO, $Y_2O_3$ were used for promoting the reduction and nitridiation aeaction. The present study was conducted to investigate the effects of silica-carbon ratio ($SiO_2$/C=weight ratio), raction time gas flow rate pellet size and powder packing on synthesis of $\beta$-Sialon from Wando pyropyllite.

• 한국자원식물학회지
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• 제20권4호
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• pp.309-311
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• 2007

남부지방에서 답리작으로 휴경답의 제고를 위하여 골풀의 시비량을 구명코자 시험하였던바 묘상에서의 시비량은 $N-P_{2}O_{5}-K_{2}O=60-30-60kg/10a$의 양으로 육성한 묘들은 본답에 가서도 수량 및 수량구성요소가 우수하였다. 따라서 골풀의 묘상 시비량은 $N-P_{2}O_{5}-K_{2}O=60-30-60kg/10a$ 이여야 된다고 생각된다.

• 한국토양비료학회지
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• 제3권1호
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• pp.1-10
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• 1970

수도(水稻)에 있어서 가리(加里)의 시용(施用)이 규회석(珪灰石)의 효과에 미치는 영향(影響)을 밝히기 위(爲)하여 Pot시험(試驗)을 실시(實施)하고 정조수량(精租收量)을 증가(增加)시킨 원인(原因)을 수량(收量) 및 수량구성요소(收量構成要素)와 수도(水稻)의 생육시기별(生育時期別) 토양(土壤) 및 식물체분석성적면(植物體分析成績面)에서 검토(檢討)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 가리(加里)의 효과는 규회석(珪灰石)이 시용(施用)되었을 때에 더 커지며 규회석(珪灰石)의 시용량(施用量)이 많을수록 가리(加里)의 요구량(要求量)도 많아진다. 2. 가리(加里)와 규회석(珪灰石)의 시용(施用)은 토양(土壤) 및 고중(藁中)의 가리(加里), 석회(石灰) 및 규산(珪酸)의 농도(濃度)를 증가(增加)시키며 $SiO_2/N$ 및 $K_2O/N$의 비율(比率)을 높여 정조수량(精租收量)을 증가(增加)시켰다. 3. 규회석(珪灰石)을 300kg/10a 이하(以下) 시용(施用)하였을 때에는 가리(加里)는 8kg/10a 에서 수량(收量)이 제일 높았으나 규회석(珪灰石)이 600kg/10a 시용(施用)되었을 때에는 가리(加里) 16kg/10a에서 수량(收量)이 제일 높았다. 4. 규회석(珪灰石)의 시용(施用)은 주당수수(株當穗數)와 수당립수(穗當粒數)는 감소(減少)시키고 등숙율(登熟率)과 천립중(千粒重)은 증가(增加)시키는 경향(傾向)이며 규회석(珪灰石) 시용(施用)으로 증가(增加)된 고중(藁中)의 CaO와 $SiO_2$는 주당수수(株當穗數)와 수당립수간(穗當粒數間)에는 부(負)의 상관(相關)이었으나 등숙율(登熟率)과 천립중(千粒重)과는 정(正)의 상관(相關)이 있었다. 5. 가리(加里)의 시용(施用)은 주당수수(株當穗數)와 수당립수(穗當粒數)를 증가(增加)시키는 경향(傾向)이며 가리시용(加里施用)으로 증가(增加)된 고중(藁中)의 $K_2O$와 수당립수(穗當粒數)와는 정(正)의 상관(相關)이 있었다. 6. 질소(窒素)의 흡수량(吸收量)은 가리(加里)와 규회석(珪灰石)의 시용(施用)이 증가(增加)함에 따라 감소(減少)하는 경향(傾向)이며 $SiO_2/N$ 비율(比率)은 가리(加里)와 규회석(珪灰石) 시용량(施用量)이 증가(增加)할수록 증가(增加)한다. 7. $K_2O/N$ 비율(比率)은 가리(加里)를 시용(施用)할수록 증가(增加)되며 가리무시용구(加里無施用區)에서는 규회석(珪灰石) 시용량(施用量)에 따라 감소(減少)하였다.

• 산업경영시스템학회지
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• 제20권43호
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• pp.205-209
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• 1997

One objective of the u control chart is to detect changes of mean nonconformities per unit occurred owing to various causes. This paper shows the detection probability using the Poisson distribution for various parameters, that is, subsample size n, mean nonconformities per unit $u_o$, and $u_o's$ change ratio k. We find that (1) as $u_o$ increases the smaller n is required for the same detection probability and the same change ratio; (2) as k gets away from 1 the smaller n is required; (3) the bigger n is required for the bigger detection probability. Several tables are given from our findings and are hoped to be used as guidelines for u chart users.