• The Korean Journal of Ceramics
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• 제6권1호
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• pp.43-46
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• 2000

$H_4Nb_6/O_{17}$/CdS nanocomposites which intercalated CdS particles, less than 0.8nm thickness, in the interlayer of $H_4Nb_6/O_{17}$ were prepared by the successive ion exchange reactions of $H_4Nb_6/O_{17}$ with $Cd^{2+}$ and $C_3H_7NH_3_+$, followed by the reaction with $H_2S$ gas. $H_4Nb_6/O_{17}$/CdS photocatalytically reduced $NO_3$￣ to $NO_2$￣ and $NH_3$in the presence of sacrificial hole acceptor such as methanol under visible light irradiation (wavelength>400nm), although unsupported CdS showed no noticeable photocatalytic activity for $NO_3$￣ reduction. The catalytic activity of $H_4Nb_6/O_{17}$/CdS greatly enhanced with co-doping of Pt particles in the interlayer.

• 한국산학기술학회논문지
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• 제13권11호
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• pp.5610-5614
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• 2012

암모니아를 환원제로 사용하는 선택적촉매환원법(Selective Catalytic Reduction, SCR)에서 촉매의 다양한 공정조건에서의 질소산화물 전환특성을 조사하였다. $H_2$-TPR을 통해 Mn, Cu가 포함된 탈질촉매의 경우 저온에서의 산소사용능력으로 우수함을 확인할 수 있었다. 탈질촉매 #1의 경우 반응온도가 증가함에 따라 탈질효율이 감소하나 탈질촉매 #2의 경우 반응온도가 증가함에 따라 탈질효율이 증가하다가 일정하였다. 이러한 현상은 두 촉매의 $NH_3$ 산화능력의 차이에 의한 것이다.

• 대한지역사회영양학회지
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• 제26권2호
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• pp.111-121
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• 2021

Objectives: This study examined ways to promote desirable eating habits by choosing foods with low sugar contents and provide nutrition education in adolescents. Methods: This study was a cross-sectional survey. The sugar reduction perception and knowledge, sugary food preference, and intake frequency of 487 male and female high school students in Incheon were analyzed comparatively. Results: Approximately 94.9% and 94.5% of the subjects were unaware of the promotion of a sugar reduction policy and the sugar reduction in the basic guidelines for school meals, respectively. Approximately 95% of them had not received any sugar reduction nutrition education, and 90% were not interested in sugar reduction. The perception for sugar reduction was significantly higher in girls (3.43 out of 5 points) than in boys (3.16 out of 5 points) (P < 0.001). Knowledge about sugar was 3.65 out of 6 points in girls and 3.04 points in boys (P < 0.001). The preference and intake frequency for fruits of the total students were 4.24 out of 5 points and 2.56, respectively. For beverages, the preference was significantly higher in boys (3.97 points) than in girls (3.70 points) (P < 0.001), and the intake frequency was significantly higher in boys (2.26 points) than in girls (2.08 points) (P < 0.001). The preference for snacks was significantly higher for girls (4.19 points) than boys (4.02 points) (P < 0.01), and the intake frequency was 2.22 points in boys and 2.17 in girls, showing no significant difference. Sugar reduction perception and knowledge about sugar showed significant negative correlations with the snack intake frequency (r = -0.11, P < 0.05; -0.13, P < 0.05) after adjusting for gender, grade, and body mass index. Conclusions: The high school students' perception of sugar reduction was very low, and there was a significant correlation with sugary food intake, suggesting that the sugary food intake will decrease as the sugar reduction perception and knowledge about sugar increase.

• 공업화학
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• 제24권6호
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• pp.599-604
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• 2013

본 연구는 공침법으로 Ti가 첨가된 Mn-Cu 혼합산화물을 이용하여 $200^{\circ}C$ 이하의 저온 영역에서의 $NH_3$-SCR 반응특성에 관한 것이다. 제조된 촉매들은 BET, XRD, XPS, TPD를 이용하여 각각의 물리/화학적 특성을 분석하였다. Mn-Cu 혼합산화물은 매우 큰 비표면적과 저온에서의 높은 SCR 효율을 나타내었으며, Ti가 첨가된 경우 상대적으로 높은 SCR 효율과 $N_2$ 선택도를 나타내었다. 이러한 결과는 Ti가 첨가됨에 따라 화학 흡착된 산소종($Me-O_{ads}$)이 증가하여 NO가 $NO_2$로의 산화가 촉진되고, $Mn^{3+}$와 같은 $NH_3$의 흡착점의 수가 증가되었기 때문이다.

• 접착 및 계면
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• 제12권4호
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• pp.133-137
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• 2011

그래파이트 옥사이드(GO)를 tetramethylammonium hydroxide (TMAOH)수용액을 이용하여 나노 크기로 분산되어 박리된 그래파이트 옥사이드(Exfoliated Graphite Oxide: EGO)를 제조하였다. 얻어진 EGO를 $Zn(NO_3)_2{\cdot}6H_2O$, $Al(NO_3)_3{\cdot}9H_2O$, urea, trisodium citrate의 혼합용액에 넣어 격렬히 교반 후 고압멸균기에서 열수 처리하여 동시에 환원된 그래핀(RGO)과 Zn-Al 이중층상 수산화물(LDH)의 나노 복합재료를 제조하였다. 즉, EGO의 표면에 두 개의 금속이온이 흡착된 후 열수처리 환원을 통하여 Zn-Al 이중층상 수산화물이 RGO의 표면에 자유롭게 성장하여 복합화 되었다. 얻어진 그래핀/Zn-Al LDH의 구조 및 형태와 열적 특성은 FE-SEM, EDX, TEM, FT-IR, XRD, TGA와 DSC를 통하여 분석하였다.

• 한국연소학회지
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• 제4권2호
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• pp.63-74
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• 1999

The effects of EGR and premixedness on NO formation have been numerically investigated. The flame structure is classified into three categories; premixed flame($=1)$, rich/lean premixed flame(${\alpha}=0.6$ and 0.8) and diffusion flame(${\alpha}=0$). NO formation/destruction mechanisms are assorted to thermal, reburn and Fenimore mechanisms. The temperature of unburned gas is arranged to 298 and 500 K to have access to the condition in a real internal combustion engine. The results show that all three NO formation/destruction reaction rates in the fuel rich flame zone could be decreased by EGR for rich/lean premixed flames, while those in the fuel lean flame zone are not significantly changed. Near the stagnation plane, however, only the thermal NO reaction rate is decreased. The contribution of reburn and Fenimore mechanisms for the net NO production becomes less significant as the premixedness of a flame increases. The larger amount of NO reduction with EGR is expected under the higher temperature and/or higher fuel/air premixedness conditions due to the increased contribution of the thermal mechanism. The role of Fenimore and reburn mechanisms could be important for rich premixed and diffusion flames; therefore, the effect of EGR on NO reduction could vary with fuel/air premixedness. The premixedness of a partially premixed flame changes the flame structure and could affect the NO production characteristics.

• 미생물학회지
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• 제39권3호
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• pp.175-180
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• 2003

Shewanella putrefaciens DK-1은 그람음성, 통성 혐기성 세균으로 $NO_{3}$, Fe(III), Mn(IV), humic acid와 같은 다양한 전자수용체를 이용한다. S. putrefaciens DK-1의 전자공여체의 이용능력은 제한적이며, lactate나 formate는 좋은 전자공여체로 이용되지만 acetate나 toluene은 이용하지 못하였다. 다양한 전자수용체간의 경쟁을 살펴보기 위해 전자수용체로 Fe(III)와 같이 $NO_{3}^{-}$, $NO_{2}^{-}$를 넣어 주었을 매 Fe(III)의 환원은 저해되었다. 또한 5. putrefaciens DK-1은 전자수용체로 토양에 광범위하게 존재하는 humic acid를 이용하였으며, 환원된 humic acid는 질산염에 의해서 다시 산화되었다. Fe(III) 환원능이 있는 환경 시료를 이용하여 탄소, 질소, 인과 같은 제한 요인이 Fe(III) 환원세균의 활성에 미치는 효과를 조사하였다. 천호지의 저질토와 대호의 농토에 각각 탄소원, 질소원, 인을 첨가해 주었을 경우 S. putrefaciens DK-1과 탄소원을 동시에 첨가해 주었을 때 가장 높은 철 환원능을 보여주었다.

• 한국안전학회지
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• 제15권2호
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• pp.92-96
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• 2000

In this experiment, we studied about concentration characteristics of $NO_x$ and generation of ozone in the reactor of corona discharge type by using mixed gas of $NO/N_2$ and $N_2/O_2$. In the case of the initial NO concentration increased, decrease rate of NO concentration was weakened and discharge input power of minimum NO concentration became high. When NO concentration was high, NO decomposition limit was appeared. And NO reduction rate was decreased, when initial NO concentration and discharge input power increased. When discharge input power was 5W, we could know the most proper energy value for treatment of NO. When the concentration of initial NO increased, generation of ozone decreased and in the case of same concentration of NO, according to discharge input power increase, generation of ozone increased.

• 한방비만학회지
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• 제3권1호
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• pp.61-67
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• 2003

Objectives : To compare the reduction of thigh circumference between electro acupuncture treatment group and no treatment controlled group. Method : Trial was carried out 24 volunteers for 2 weeks. Volunteers were divided into 2 groups ; electro acupuncture and very low calorie diet group(n=8) or only very low calorie diet group(n=9). The main outcome of measure was the reduction of thigh circumference(cm) per weight loss(kg). Result: The main outcome measure showed no significant difference(p=0.14). There was no significant difference in weight loss(p=0.67) either.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권2호
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• pp.132-140
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• 2010

Purpose: The aim of this study is to identify the usefulness of unilateral mandibular angle ostectomy, so-called "Lateral Angle Reduction", in asymmetric prognathism patients by the assessment of postoperative stability and esthetic results Patients and methods: For the retrospective study, 10 skeletal class III mandibular asymmetry patients who were performed SSRO and unilateral mandibular angle ostectomy, Lateral Angle Reduction, was selected. Lateral and posterioanterior cephalogram was taken before surgery (T0), 1day after surgery (T1) and 6month after surgery (T2). To know the esthetic results the facial width and lateral facial contour were examined on posterioanterior cephalogram and to know the postoperative stability B point and Incisor inferius was examined on lateral cephalogram. Statistical analysis was performed. Results: From T0 to T1, Intergonial width was significantly decreased, dominantly at shortened side but no significant changes at lengthened side. Those were well-maintained during 6 months. Lateral facial angle and Ramus angle was significantly decreased on only shortened side from T0 to T1. As a result, after surgery, there were no significant differences in all measurements between shortened side and lengthened side. Ramus deviation angle in shortened side and ramus angle in lengthened side which reflect the angulation of ramus on frontal plane didn't show significant changes after surgery and during postsurgical periods. Lower dental midline showed no statistical changes during postsurgical period. The relapse rate on B-point was 11.92%. Conclusion: Unilateral "Lateral angle reduction" in the asymmetric mandible is valuable to obtain the narrow lower face and symmetric facial contour with a good stability.