• 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.

• 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.

• 한국세라믹학회지
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• 제29권5호
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• pp.347-356
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• 1992

Various kaolin samples with different alumina content were prepared from calcined admixture of kaolin and ammonium sulfate by varying the treatment time in sulfuric acid. Samples were nitridated under N2 or N2-H2 atmosphere with changing the amount of added carbon, the reaction time and temperature. As the alumina content lowered, the size of kaolin particles decreased and the specific surface area increased. XRD analysis indicated that ${\alpha}$-quartz remained by decomposition of halloysite and meta-halloysite. Experimental results of nitridation behavior are summerized as follows; 1) Nitridation under N2 atmosphere. With the increase of C/SiO2 ratio and with the decrease of Al2O3 content, disappearance of XRD pattern peaks of mullite, ${\alpha}$-quartz and ${\alpha}$-Al2O3 were accelerated at 1300$^{\circ}C$. SiC was the main phase in the reaction product of acid-treated kaolin samples nitridated at 1300$^{\circ}C$ for 10 hours regardless of C/SiO2 ratio. But the XRD peak intensities of ${\beta}$-Si3N4, ${\beta}$-sialon and SiC did not show much difference when untreated raw kaolin was fired at the same condition. When the ratio of C/SiO2 was 3.5, ${\beta}$-sialon and ${\beta}$-Si3N4 existed in the reaction product of about 22% alumina containing kaolin sample fired at 1350$^{\circ}C$ for 7 hours. Only ${\beta}$-sialon existed in the same sample fired at 1400$^{\circ}C$ for 10 hours. ${\beta}$-sialon was obtained from all of the acid-treated kaolin samples fired at 1400$^{\circ}C$ for 40 hours, but AlN and SiC remained in the untreated kaolin sample. Z value of the ${\beta}$-sialon obtained from the 22% alumina containing kaolin sample fired at 1400$^{\circ}C$ for 40 hours was about 1.3(XRD) and 1.5(EDS). 2) Nitridation under 80N2+2OH2 mixed gas atmosphere with the C/SiO2 ratio of 1 Mullite was not found, but ${\alpha}$-Si3N4, and ${\beta}$-sialon were present in the reaction product of about 22% alumina containing kaolin sample fired at 1300$^{\circ}C$ for 10 hours. When untreated kaolin sample was nitridated at the same condition, mullite remained. AlN and SiC were not found in the reaction product of about 22% alumina containing kaolin sample fired at 1350$^{\circ}C$ for 5 hours. On the other hand, AlN and SiC remained in the product of untreated kaolin fired at the same condition.

• 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.

• 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.

• 대한기계학회논문집B
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• 제29권2호
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• pp.255-262
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• 2005

A comprehensive experimental and numerical study has been conducted to understand the influence of $CH_{3}Cl$ addition on $CH_4/O_2/N_2$ premixed flames under the oxygen enrichment. The laminar flame speeds of $CH_4/CH_{3}Cl/O_2/N_2$ premixed flames at room temperature and atmospheric pressure are experimentally measured using Bunsen nozzle flame technique, varying the amount of $CH_{3}Cl$ in the fuel, the equivalence ratio of the unburned mixture, and the level of the oxygen enrichment. The flame speeds predicted by a detailed chemical kinetic mechanism employed are found to be in excellent agreement with those deduced from experiments. Even though the molar amount of $CH_{3}Cl$ in a methane flame is increased, temperature at the postflame is not significantly varied, but the calculated heat release rate and emission index of NO are largely decreased for the oxygen enhanced flame. The function of $CH_{3}Cl$ as inhibitor on hydrocarbon flames becomes weakened as the level of the oxygen enrichment is increased from 0.21 to 0.5.

• 한국세라믹학회지
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• 제26권1호
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• pp.13-20
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• 1989

After sintering Si3N4 containing 20wt% of variable composition ratio of Y2O3 and Al2O3 at 1$600^{\circ}C$, the specimens were annealed at 125$0^{\circ}C$ and 135$0^{\circ}C$ for 5, 10, 15 hours in order to crystallize the remanining oxynitride glass phases. The main grain-boundary crystalline phases in the Si3N4-Y2O3-Al2O3 system were melilite and YAG. By annealing 15hrs. at 125$0^{\circ}C$, almost all of the glasses were crystallized. During the growth of melilite, lattice volyume of $\beta$-Si3N4 was increased as Al3+ and O2- ions in the oxynitride glass diffuse into $\beta$-Si3N4 lattice, but during the growth of YAG, lattice volume of $\beta$-Si3N4 was decreased by reverse diffusion of Al3+ and O2- ions. In case of crystallization of glass phase to melilite, thermal expansion of sample was decreased, but in case of crystallization to YAG, inverse phenomen on was observed.

• 대한화학회지
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• 제18권3호
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• pp.194-201
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• 1974

네자리 schiff리간드는 salicylaldehyde와 m-phenylenediamine을 Duff-반응 시킴으로써 N,N-bis(salicylaldehyde)-m-phenylenediimine을 합성하고 이 리간드와 Cu(II), Ni(II), Co(II) 및 Zn(II) 이온들과의 새로운 착물 Cu(II)$[C_{20}H_{14}O_2N_2]{\cdot}2H_2O, Co(II)[C_{20}H_{14}O_2N_2]{\cdot}2H_2O$ 및 Zn(II)$[C_{20}H_{14}O_2N_2]{\cdot}4H_2O$들을 합성하였다. 이들 착물에 대하여 가시부 흡수스펙트럼, 적외선스펙트럼, TGA, X-ray 회절 및 원소분석 결과에 의하여 Cu(II), Ni(II) 및 Co(II) 착물들은 리간드와 금속이 1:1 몰비 및 2수화물의 6배위 착물로 주어지며 Zn(II) 착물은 1:2 몰비 4배위 착물로 주어짐을 알았다

• 한국세라믹학회지
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• 제24권1호
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• pp.23-32
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• 1987

Synthesis of high purity ultrafine Si3N4 and ${\beta}$-Sialon powders was investigated via the simultaneous reduction and nitriding of amorphous SiO2, SiO2-Al2O3 system prepaerd by hydrolysis of alkoxides, using carbonablack as a reducing agent. In Si(OC2H5)4-C2H5 OH-H2 O-NH4OH system, hydrolysis rate increased with increasing reaction temperature and pH. Pure ${\alpha}$-Si3N4 was formed at 1350$^{\circ}C$ for 5 hrs in N2 atmosphere. In Si(OC2H5)4-Al(OC3H7)3-C6H6-H2 O-NH4OH system, weight loss increased as Si/Al ratio decreased. Single phase ${\beta}$-Sialon consisted of Si/Al=2 was formed at 1350$^{\circ}C$ in N2 and minor phases of ${\alpha}$-Si3N4, AIN, and X-phase were existed besides theSialon phase at other Si/Al ratios. The Si3N4 and Sialon powders synthesized from alkoxides consisted of uniform find particles of 0.05-0.2$\mu\textrm{m}$ in diameter, respectively.