• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.46.2-46.2
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• 2011

CuInSe2 (CIS)계 화합물은 3족 원소(Ga, Al) 또는 6족 원소(S)를 첨가하여 밴드갭 조절이 가능하다는 장점을 가지고 있다. 실제로 동시 증발법으로 Ga을 첨가하여 만든 CuIn0.7Ga0.3Se2(CIGS) 태양전지는 약20%의 높은 효율 보이고 있다. 그러나 최고 효율을 달성한 동시 증발법은 대면적화가 어렵다는 점이 상용화의 걸림돌로 작용하고 있다. 따라서, 그 대안으로 대면적화가 용이한 스퍼터링 및 셀렌화 공정 연구가 진행되고 있다. 그러나 스퍼터링/셀렌화 공정은 Cu-In-Ga 금속 전구체의 셀렌화 시 Ga이 Mo쪽으로 이동하여 CIS/CGS 2개의 상으로 형성된다는 큰 단점을 갖고 있다. 이를 해결하기 위해 셀렌화 후 다시 H2S 기체 분위기에서 열처리하여 표면 밴드갭을 증가시키는 공정이 사용되고 있으나, 이는 열처리 과정이 2번 필요하다는 단점을 갖고 있다. 이러한 단점을 해결하고자 본 연구에서는 금속 전구체의 구조, 셀렌화 공정 조건 및 전구체 내의 상(phase) 조절을 통해 셀렌화 시 Ga segregation을 억제하고자 하였다. 특히 전구체의 상 조절을 통해서 Ga의 이동을 크게 완화시킬 수 있음을 확인하였다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.194-197
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• 2001

본 연구에서는 유류 오염토양 복원을 위한 효율적인 이동형 연속식 토양세척 장비를 개발하여 현장 적용 가능성을 검토하였다. 진세척조는 내부에 스크류를 설치함으로써 주입되는 오염토양과 세척용액의 기계적 교반에 의한 원활한 접촉과 토양간의 마찰 등으로 인하여 토양으로부터 오염물질의 탈착이 효과적으로 이루어지도록 하였다. 전세척조 외부에 위치한 주세척조는 전세척조에서 탈착된 오염물질과 미세입자를 원 토양으로부터 효율적으로 분리하기 위한 헹굼작용과 배출부에서 미세입자를 포함하는 세척 유출수가 효율적으로 분리 배출이 될 수 있도록 설계.제작하였다. 현장 적용 실험결과, 설계 목표치인 토양 주입 속도 15m$^3$/day, 계면활성제 POE$_{5}$POE$_{14}$의 비 1:1 (농도 0.1%), 세척수/토양 비 (부피/중량비) 1, 전세척조 회전속도 18rpm. 주세척조 회전속도 5rpm의 운전조건에서 90% 이상의 높은 세척효율을 나타내었다.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.955-960
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• 2008

We investigated and estimated at the characteristics of decomposition and mineralization of benomyl using a design of experiment(DOE) based on the general factorial design in an E-beam process, and also the main factors(variables) with benomyl concentration(X$_1$) and E-beam irradiation(X$_2$) which consisted of 5 levels in each factor was set up to estimate the prediction model and the optimization conditions. At frist, the benomyl in all treatment combinations except 17 and 18 trials was almost degraded and the difference in the decomposition of benomyl in the 3 blocks was not significant(p > 0.05, one-way ANOVA). However, the % of benomyl mineralization was 46%(block 1), 36.7%(block 2) and 22%(block 3) and showed the significant difference of the % that between each block(p < 0.05). The linear regression equations of benomyl mineralization in each block were also estimated as followed; block 1(Y$_1$ = 0.024X$_1$ + 34.1(R$^2$ = 0.929)), block 2(Y$_2$ = 0.026X$_2$ + 23.1(R$^2$ = 0.976)) and block 3(Y$_3$ = 0.034X$_3$ + 6.2(R$^2$ = 0.98)). The normality of benomyl mineralization obtained from Anderson-Darling test in all treatment conditions was satisfied(p > 0.05). The results of prediction model and optimization point using the canonical analysis in order to obtain the optimal operation conditions were Y = 39.96 - 9.36X$_1$ + 0.03X$_2$ - 10.67X$_1{^2}$ - 0.001X$_2{^2}$ + 0.011X$_1$X$_2$(R$^2$ = 96.3%, Adjusted R$^2$ = 94.8%) and 57.3% at 0.55 mg/L and 950 Gy, respectively. A Microtox test using V. fischeri showed that the toxicity, expressed as the inhibition(%), was reduced almost completely after an E-beam irradiation, whereas the inhibition(%) for 0.5 mg/L, 1 mg/L and 1.5 mg/L was 10.25%, 20.14% and 26.2% in the initial reactions in the absence of an E-beam illumination.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.3
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• pp.174-180
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• 2003

This study investigated the size selectivity of the round traps for greenling (Hexagrammos otakii) in the western sea of Korea. The selection curve for the greenling from the experiments on Oct. 2000 and Ar. 2001 was fitted by Kitahara's method to a polynomial equation and two parameter logistic selection curve. The selectio curve of the latter was more reasonable than that of the former. The equation of selectivity curve obtained using a logistic function with least square method was , s(R)=1/1+exp(-1.1169R+6.4565), where R=1/m, and 1 and m are total length and mesh size, respectively. The size selectivity curve showed that the current regulated mesh size(35mm) in case of the round trap was close to the L50 (37.0mm) of the selection curve for the biological minimum length (21.4cm) of the greenling.

• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.103-110
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• 2005

In this paper, the characteristics of excessive horizontal stress components in Korea were studied using more than five hundred measured data set of in-situ hydraulic fracturing test. Based on the in-situ testing data, the magnitude and orientation of the horizontal stress component and variation of stress ratio (K) with depth were investigated. And also horizontal stress magnitude versus depth relationships and distribution limits of stress ratio components were suggested. For the depth less than 310 m in the entire territory, the stress ratio has a tendency to diminish and stabilize with depth, but fur some areas, it was revealed that the excessive horizontal stress fields with stress ratio close to 3.0 below 200 m in depth have formed. The results from the investigation of excessive horizontal stress regions showed that there existed several regions where the localized excessive horizontal stress was big enough to potentially induce brittle failure around the openings at less than 300 m in depth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.9
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• pp.1295-1304
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• 2010

The purpose of this study was to investigate the BMI, dietary behaviors, body satisfaction and factors affecting the weight control interest according to gender of middle school students (195 boys and 251 girls) in Wonju area. The average height and weight of the boys were $164.8{\pm}8.3\;cm$ and $55.5{\pm}12.3\;kg$ respectively. Those of the girls were $158.8{\pm}5.0\;cm$ and $48.7{\pm}7.4\;kg$ respectively. The average body mass index (BMI) of the boys and girls was 20.3 and 19.3 respectively. In both boys and girls, 69.7% of them had regular meals and the main reason for skipping meals was insufficient time to eat due to oversleeping (33.6%). Most of the subjects consumed snacks more than once a day (95.5%). The dietary intake attitude score of the girls ($35.08{\pm}5.91$) was higher than that of the boys ($33.81{\pm}5.45$) (p<0.01). The eating disorders score of the girls ($12.92{\pm}6.22$) was higher than that of the boys ($10.70{\pm}9.82$) (p<0.01). Also, 87.2% of the subjects showed normal behavior and 12.8% of the subjects had eating disorders, but there was no significant difference according to gender. The body satisfaction score of the boys ($30.16{\pm}5.08$) was higher than that of the girls ($28.00{\pm}5.52$) (p<0.001). In general, body satisfaction score correlated positively with dietary intake attitude score, but correlated negatively with eating disorders score (p<0.05). Multiple regression analysis revealed that body satisfaction score was the most significant variable which affected the weight control interest. Therefore, development of the nutrition education program for adolescents will be effective not only for the improvement of dietary behaviors but also for the positive change in the misleading perception about the ideal body shape.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.3
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• pp.449-454
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• 2010

Extraction characteristics of pumpkin (Cucurbita moschata Duch.) and the functional properties of the corresponding extracts were monitored by the response surface methodology (RSM). The maximum electron donating ability was found as 24.57% at the conditions of 33.13 watt microwave power, 53.67% ethanol concentration and 3.76 min extraction time. The maximum tyrosinase inhibition was 96.59% at 56.21 watt, 68.02% and 7.97 min. The SOD-like activity was 45.57% at 36.00 watt, 71.51% and 5.28 min. The total polyphenol content was 85.02% at 127.39 watt, 76.18% and 2.68 min. Based on superimposition of four dimensional RSM with respect to electron donating ability, tyrosinase inhibition, SOD-like activity and total polyphenol contents obtained under the various extraction conditions, the optimum ranges of extraction conditions were found to be microwave power of 72~144 watt, ethanol concentration of 0~38% and extraction time of 6~9 min.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.938-943
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• 2018

Thin nano-sized fibres were prepared by an electrospinning method. The spinning appratus consisted of pump for polymer injection, nozzle and nozzle rotus, and an aluminum plate collected the polymer fibers. Its surface was chemically modified for selective improved adsorption of carbon monoxide at indoor level. The chemical activation enabled to form the fibres 250-350 nm in thickness with pore sizes distributed between 0.6 and 0.7 nm and an average specific surface area of $569m^2/g$. The adsorption capacities of pure (100%) and indoor (0.3%) $CO_2$, of which level frequently appears, at the ambient condition were improved from 1.08 and 0.013 to 2.2 and 0.144 mmol/g, respectively. It was found that the adsorption amount of $CO_2$ adsorbed by the chemically activated carbon nanofiber prepared through chemical activation would vary depending on the ratio of specific surface area and micropores. In particular, chemical interaction between adsorbent surface and gas molecules could enhance the selective capture of weak acidic $CO_2$.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.141-146
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• 1995

Changes of physicochemical properties of citron juice prepared by two different extraction methods, rotary-crushing and belt-pressing method, were investigated during the storage at $5^{\circ}C$ and $-20^{\circ}C$. Temperature drop of citron juice extracted by belt-pressing method was faster than that of citron juice prepared by rotary-crushing method and its freezing point was $0.8{\sim}0.9^{\circ}C$. During the storage, pH of stored citron juice with rotary-crushing method was increased up to 3.5 after 6 months storage while that of citron juice extracted by belt-pressing method was not changed significantly during the same storage time. Acidity of rotary-crushed citron juice was reduced a little more than that of belt-pressed citron juice during the storage. However, changes of soluble solid content were influenced largely by the storage temperature than by the extraction method. Contents of formol nitrogen and vitamin C were reduced remarkably in all of stored citron juice and $92{\sim}82%$ of farmol nitrogen and $72{\sim}43%$ of vitamin C were remained after 6 months of storage. Among the changes of color value, L values were reduced in the whole stored citron juice and a and b value had a different change pattern respectively according to the extraction and storage temperature. Changes in the content of both amino acid and fatty acid compositions was also observed after same storage period. Especially, in the case of change of fatty acid composition, content of linoleic acid and linolenic acid were reduced after 6 months storage, while those of palmitic acid, stearic acid and oleic acid were increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.1052-1058
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• 2005

Structured lipid (SL) was synthesized by enzymatic interesterification with algae oil containing docosahexaenoic acid (DHA) and soybean oil in the stirred-batch type reactor. The reaction was performed for 15hr at $65^{\circ}C$ with 300 rpm catalyzed by sn-1,3 specific Lipozyme RM 1M lipase from Rhizomucor miehei ($11\%$ by weight of total substrates) in the absent organic solvent. SL contained $87.1\;area\%$ triacylglycerol (TAG), $12.1\;area\%$ diacylglycerol (DAG), $0.6\;area\%$ monoacylglycerol (MAG), and $0.2\;area\%$ free fatty acid (FFA). Major fatty acid profiles of SL were DHA $(15.7\;mol\%)$, linoleic $(31.1\;mol\%)$, palmitic $(20.2\;mol\%)$, oleic $(13.5\;mol\%)$ and eicosapentaenoic acid $(EPA,\;6.6 mol\%)$. SL contained the newly synthesized several peaks. Iodine and saponification of SL were 206.7 and 183.8. SL color showed darker and redder than soybean oil, and appeared the most yellowish color among SL, soybean, and algae oil.