• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.237-244
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• 2019

BACKGROUND: Impact of incorporating hairy vetch into soil on mitigating nitrous oxide (N₂O) emissions from maize field in South Korea has not been investigated, whereas impacts on soil properties and nutrients for crops have been investigated. Therefore, this study was conducted to examine N₂O emission from upland soil incorporated with hairy vetch for one year in maize field. METHODS AND RESULTS: Hairy vetch was grown in an upland soil from November, 2017 to May, 2018 and incorporated into soil on May 25 of 2018. Control and conventional treatment (NPK) were included for comparison. Gas samples were collected weekly for a year to examine N₂O emissions from the soil. Chemical nitrogen (N) fertilizer stimulated N₂O emission in short term resulting in the greatest cumulative N₂O emission in NPK (6.72 kg N₂O ha^-1) compared to the control (4.04 kg N₂O ha^-1) and hairy vetch-incorporated field (5.43 kg N₂O ha^-1), and the greatest yield of maize from NPK, because total N input was much greater by NPK (186 N kg ha^-1) than by hairy vetch (81.6 N kg ha^-1). CONCLUSION: Incorporation of hairy vetch reduced N₂O emissions from the maize compared to the NPK-treated field. However, further research on improving crop productivity with incorporation of hairy vetch is needed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.295-301
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• 2014

In the absence of a sorting algorithm faster than O(n log n), Quicksort remains the best and fastest of its kind in practice. For given n data, Quicksort records running in O(n log n) at best and $O(n^2)$ at its worst. In this paper, I propose an algorithm by which 3-points average P=(L+M+H)/3 is set as a pivot for first array L=a[s], last array H=a[e], and middle array $M=a[{\lfloor}(s+e)/2{\rfloor}]$ in order to find the more fast than Quicksort. Test results prove that the proposed 3-points average pivot Quicksort has the time complexity of O(n log n) at its best, average, and worst cases. And the proposed algorithm can be reduce the $O(n^2)$ time of Quicksort to O(n log n).

• Journal of Energy Engineering
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• v.20 no.3
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• pp.191-199
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• 2011

The char burn-out and NOx emissions from sub-bituminous coal were investigated in drop tube furnace under $O_2/N_2$ and $O_2/CO_2$ environments with different $O_2$ concentrations of 12, 21 and 31%. Results show that the char burn-out rate is faster as $O_2$ concentration increases higher and char burn-out rate under $O_2/CO_2$ decreases due to the lower oxygen diffusion into coal surface through the $CO_2$ rich boundary layer. NO concentration increases with increasing $O_2$ concentration, but declines at $O_2$ concentration of 31%. Meanwhile, NO emission indexes decreases monotonically with increasing $O_2$ concentration, which indicates that more NO reduction occurs with higher $O_2$ concentration probably due to greater HCN formation. For all conditions of $O_2$ concentration, the NO concentration under $O_2/N_2$ maintains higher than those of $O_2/CO_2$ due to presence of thermal NO.

• Korean Journal of Materials Research
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• v.29 no.8
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• pp.463-468
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• 2019

The electrical and interfacial properties of $HfO_2/Al_2O_3$ and $Al_2O_3/HfO_2$ dielectrics on AlN/p-Ge interface prepared by thermal atomic layer deposition are investigated by capacitance-voltage(C-V) and current-voltage(I-V) measurements. In the C-V measurements, humps related to mid-gap states are observed when the ac frequency is below 100 kHz, revealing lower mid-gap states for the $HfO_2/Al_2O_3$ sample. Higher frequency dispersion in the inversion region is observed for the $Al_2O_3/HfO_2$ sample, indicating the presence of slow interface states A higher interface trap density calculated from the high-low frequency method is observed for the $Al_2O_3/HfO_2$ sample. The parallel conductance method, applied to the accumulation region, shows border traps at 0.3~0.32 eV for the $Al_2O_3/HfO_2$ sample, which are not observed for the $Al_2O_3/HfO_2$ sample. I-V measurements show a reduction of leakage current of about three orders of magnitude for the $HfO_2/Al_2O_3$ sample. Using the Fowler-Nordheim emission, the barrier height is calculated and found to be about 1.08 eV for the $HfO_2/Al_2O_3$ sample. Based on these results, it is suggested that $HfO_2/Al_2O_3$ is a better dielectric stack than $Al_2O_3/HfO_2$ on AlN/p-Ge interface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.726-729
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• 2000

Though L $a_{1+x}$S $r_{2-x}$M $n_2$ $O_{7}$ n=2 R-P phases have been well known to have CMR effect, it was generally believed that n=1 phase was insulating. But recently monolayered perovskite $Ca_{2-x}$L $n_{x}$Mn $O_4$phase has been reported to show magnetoresistance. In this study, layered perovskite $Ca_{2-x}$L $n_{x}$Mn $O_4$ (x=0, 0.5, Ln=Pr, Nd, Sm, Gd) phases were synthesized by solid state reaction and their structures were refined by Rietveld method. The space groups of $Ca_2$Mn $O_4$, N $d_{0.5}$C $a_{1.5}$Mn $O_4$phases were refined as C2cb and Fmmm, respectively.y.ely.y.y.y.y.y.y.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.161-161
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• 2012

결정질 TiCrN과 AlSiN 나노층이 교대로 구성하는 나노 다층 TiAlCrSiN 박막은 음극 아크 플라즈마 증착법에 의해 증착되었다. 나노 다층 TiAlCrSiN 박막의 산화특성들은 $600{\sim}1000^{\circ}C$사이에서 대기 중 최대 70시간동안 연구 되었다. 형성된 산화물들은 주로 $Cr_2O_3$, ${\alpha}-Al_2O_3$, $SiO_2$ 그리고 rutile-$TiO_2$들로 구성되었다. 나노 다층 TiAlCrSiN 박막이 산화하는 동안, 가장 바깥쪽의 $TiO_2$층은 Ti 이온의 외부확산에 의해, 외부 $Al_2O_3$층은 Al이온의 외부확산에 의해 형성되었다. 동시에, 내부($Al_2O_3$, $Cr_2O_3$) 혼합층과 가장 안쪽의 $TiO_2$층은 산소이온의 내부확산에 의해 형성되었다.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.489-497
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• 2002

The purpose of this study was to compare the clinical sedation effect of chloral hydrate and hydroxyzine combination with and without nitrous oxide/oxygen inhalation when young children were sedated for dental treatment. The uncooperative 20 children aged, 21 to 47 months of age(ASA Class I), participated in the study. The author examined 20 children(male 12, female 8). Each patient was assigned to receive chloral hydrate(50mg/kg) and hydroxyzine(25mg). Next appointment, each patient was assigned to receive $N_2O-O_2$, choral hydrate and hydroxyzine. Sleep, crying, movement, and overall behavior response were evaluated, and the sedative effects were evaluated by Houpt's rating scale. Pulse rate and peripheral oxygen saturation were also measured for monitoring the sedated patients during treatment period by pulse oximeter. The result were as follows : 1. In the evaluation of sleep scores, crying scores, and movement scores, chloral $hydrate/hydroxyzine/N_2O-O_2$ combination group was significantly rated high(p<0.05). 2. In the evaluation of overall behavior scores, chloral hydrate/hydroxyzine/$N_2O-O_2$ combination group was significantly rated high(p<0.05). 3. In the evaluation of overall behavior evaluation scores(by Houpt), 93.3% in chloral $hydrate/hydroxyzine/N_2O-O_2$ combination group and 63.3% in chloral hydrate/hydroxyzine combination group were rated "good" or "very good". 4. There was no adverse side effect(i.e. respiratory depression) in both group.

• Journal of the Korean Magnetics Society
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• v.10 no.3
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• pp.106-111
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• 2000

The magnetic thin films can be prepared without vacuum process and under the low temperature (<100 $^{\circ}C$) by ferrite plating. We have performed ferrite plating of M $n_{x}$Z $n_{0.22}$F $e_{2.78-x}$ $O_4$(x=0.00~0.08) films and N $i_{x}$Z $n_{0.22}$F $e_{*}$2.78-x/ $O_4$(x=0.00~0.15) films on cover glass at the substrate temperature 90 $^{\circ}C$. The crystal structure of the samples has been identified as a single phase of polycrystal spinel structure by x-ray diffraction technique. The lattice constant in the M $n_{x}$Z $n_{0.22}$F $e_{2.78-x}$ $O_4$films increases but in the N $i_{x}$Z $n_{0.22}$F $e_{*}$2.78-x/ $O_4$films decrease with the composition parameter, x. The saturation magnetization in the M $n_{x}$Z $n_{0.22}$F $e_{2.78-x}$ $O_4$films does not greatly change, in agreement with observations on bulk samples.k samples.k samples.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1295-1297
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• 1993

Properties of oxynitride films oxidized by $N_2O$ gas after thermal oxidation and $N_2O$ oxide films directly oxidized using $N_2O$ gas on the bare silicon wafer have been studied. Through the AES analysis, Nitrogen pile-up at the interface of Si/oxynitride and Si/$N_2O$ oxide has observed. Also, it could be presumed that there are differences in the mechanism of the growth of film by observing film growth. $N_2O$ oxide and oxynitride films have the self-limited characteristics. Therefore, it will be possible to obtain ultra-thin films. Nitrogen pile-up at the interfaces Si/oxynitride and Si/$N_2O$ oxide strengthens film structure and improves dielectric reliability. Although fixed charge densities and interface trap densities of $N_2O$ oxide and oxynitride films has somewhat higher than those of thermal $SiO_2,\;N_2O$ oxide and oxynitride films showed improved I-V characteristics and constant current stress.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.308-312
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• 2012

Nitrogen doped $TiO_2$ photocatalysts were prepared by ammonia for exploring the visible light photocatalytic activity. To explore the visible light photocatalytic activity of the nitrogen doped $TiO_2$ photocatalyst, the removal of methylene blue dye was investigated under the sunlight. SEM images showed that the flocculated particle sizes of N-doped $TiO_2$ decreased due to the reaction with ammonia. XRD patterns demonstrated that the samples calcined at temperatures up to $600^{\circ}C$ and doped with nitrogen using ammonia clearly showed rutile as well as anatase peaks. The XPS results showed that the nitrogen composition onto $TiO_2$ increased according to the reaction time with ammonia. Photocatalytic activity of the nitrogen doped $TiO_2$ was better than that of undoped $TiO_2$. Nitrogen doping onto the $TiO_2$ also affected the crystal type of $TiO_2$ photocatalyst.