• Explosives and Blasting
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• v.35 no.3
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• pp.15-20
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• 2017

In order to obtain the dynamic response behavior of the rock subjected to blasting loading, a shock-proof high sensitivity impact sensor which can measure high frequency dynamic force and strain events should be adopted. Because the impact sensors which uses quartz and piezoelectric element are costly, generally the strain measurement-based impact (SMI) sensors are applied to high speed loading devices. In this study, dynamic Brazilian tension tests of granitic rocks was conducted using the Nonex Rock Cracker (NRC) reaction driven-high speed loading device which adopts SMI sensors. The dynamic response of the granite specimens were monitored and the intermediate strain rate dependency of Brazilian tensile strengths was discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.426-426
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• 2012

The CIGS absorber has outstanding advantages in the absorption coefficient and conversation efficiency. The CIGS thin film solar cells have been researched for commercialization and increasing the conversion efficiency. CIG precursors were deposited on the Mo coated glass substrate by magnetron sputtering with multilayer structure, which is CuIn/CuGa/CuIn/CuGa. Then, the metallic precursors were selenized under high Se pressure by RTP method which included. Se vapor was supplied using Se cracker cell instead of toxic hydrogen selenide gas. Se beam flux was controlled by variable reservoir zone (R-zone) temperature during selenization process. Cracked Se source reacted with CIG precursors in a small quantity of Se because of small size molecules with high activation energy. The CIGS thin films were studied by FESEM, EDX, and XRD. The CIGS solar cell was also developed by layering of CdS and ZnO layers. And the conversion efficiency of the CIGS solar cell was characterization. It was reached at 6.99% without AR layer.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.704-704
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• 2013

CIGS 박막 태양전지는 I-III-VI족 화합물 반도체로서 직접천이형 에너지 밴드 구조를 가지고 있고, $1{\times}10$ cm의 높은 흡수계수를 가지고 있으며, Ga, Ag, Al을 첨가함으로써 밴드갭을 1~2.7 eV 넓은 범위로 조절가능하다. 본 연구의 목적은 Sputtering 방식과 Cracker cell을 이용한 실험으로 보다 효율적인 방식으로 CIGS 전구체 조성별 특성에 따른 구조와 전기적, 광학적 특성의 효과에 대하여 조사하였다. Cu-In-Ga 전구체는 CuGa(80-20 at.%)과 In(99.0%) target을 사용하여, Sputtering 공정으로 증착하였으며, Cracker cell이 부착된 RTP (rapid thermal processing)를 통하여 셀렌화를 진행하였다. Reservoir zone 온도는 320도, Cracking zone 온도는 900도로 유지하였으며, 진공상태에서 Se이 공급되면서 열처리가 진행되었다.Cu-In-Ga 전구체 구조에서 In의 증착시간을 변화시켜 CIGS 박막에 미치는 영향에 대해 분석하였다. 이때 기판온도는 $500^{\circ}C$로 고정하거나, $240^{\circ}C$ 열처리 후 $500^{\circ}C$에서 열처리하는 두가지를 적용하여 그 영향을 분석하였다. 또한 Selenium이 Cracking zone 온도와 열처리 시간에 따라 미치는 영향의 변화를 조사하였다. 이에 따른 CIGS 박막의 전기적 특성의 변화를 조사하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.585-585
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• 2012

$Cu(In_{1-x}Ga_x)Se_2$(CIGS) 박막 태양전지는 Chalcopyrite 계 박막 태양전지로 Cu, In, Ga, Se 각 원소의 조성을 적절히 조절하여 박막을 성장시킨다. 성장시킨 CIGS 박막은 광흡수계수가 $10^5cm^{-1}$로 다른 물질보다 뛰어나고 직접 천이형 반도체로서 얇은 두께로도 고효율의 박막 제작이 가능하다. CIGS 태양전지를 제조하는 방법은 3-stage 동시 증착법, 금속 전구체의 셀렌화 공정법, 전기 증착법 등이 있다. 그 중에 금속 전구체의 셀렌화 공정법은 다른 제조 방법에 비해 대면적 생산에 유리한 장점이 있다. 하지만 아직 상대적으로 3-stage 동시 증착법에 비해 낮은 에너지 변환 효율이 보고된다. 본 실험에서는 기존의 금속 전구체의 셀렌화 공정법과는 달리 전구체 증착과 셀렌화 공정을 동시에 하고, Se cracker를 통하여 Se 원료를 주입하는 방식인 반응성 스퍼터링 공정에서 reservoir zone의 온도 변화에 따른 특성을 분석하였다. Se cracker의 reservoir zone 온도가 증가할수록 Cu/(In+Ga) 비가 증가한다. CIGS 박막 태양전지의 구조는 Al/Ni/ITO/i-ZnO/CdS/CIGS/Mo/Soda lime glass이다. CIGS 박막의 조성비가 Cu/(In+Ga)=0.89, Ga/(In+Ga)=0.17인 박막 태양전지에서 개방전압 0.34 V, 단락전류밀도 $32.61mA/cm^2$, 충실도 56.2% 그리고 변환 효율 6.19%를 얻었다. 본 연구는 2011년도 지식경제부의 재원으로 한국에너지 기술평가원(KTEP)의 지원을 받아 수행한 연구 과제입니다(No.20093020010030).

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.553-557
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• 1988

To investigate the effect of storage humidity on the textural characteristics of crackers, their crispness and tenderness were measured by sensory and instrumental methods. Domestic cracker samples stored for 1 and 3 weeks at 4 different relative humidities of 23, 31, 51 and 79% showed the decrease in crispness intensity as the humidity increased while storage period did not affect their textural characteristics. When domestic and imported cracker samples were stored for 1 and 3 weeks at relative humidities of 31% and 79%, there was no significant difference in their textural characteristics.

• The Korean Journal of Food And Nutrition
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• v.31 no.6
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• pp.821-827
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• 2018

Ecklonia cava which is a kind of phaeophyta and belongs to Laminariales Alariaceae is a perennial seaweed distributed over Jeju and Dokdo islands. The purpose of this study evaluate antioxidant activities of Ecklonia cava crackers. Crackers were prepared with different measurements (0, 2, 4, 6, 8 g) of Ecklonia cava; indicated as S1, S2, S3, S4 and S5, and are used to examine and compare antioxidant activities, and quality characteristics. Ecklonia cava powder was used, after being extracted with 70% ethanol in hot water and done in freeze dehydration. To examine antioxidant activities of Ecklonia cava and cracker, DPPH radical scavenging activity, total phenolic and reducing power were tested. Total phenolic content was 36.86 mg GAE/g. DPPH radical scavenging activity and reducing power showed good vitality as amounts of Ecklonia cava powder increased (p<0.001). pH level decreased as amounts of power increased. L (lightness) values and b (yellowness) values decreased with an increased concentration of Ecklonia cava powder (p<0.001), whereas (redness) values didn't show tendency. S5 indicated the lowest spreadness. According to sensory evaluation, S4 (6 g) was preferred the most in terms of color, flavor, taste, appearance, texture, and overall palatability. Results suggest that Ecklonia cava powder has antioxidant effect and is useful as a functional food resource.

• Explosives and Blasting
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• v.20 no.3
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• pp.39-48
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• 2002

우리나라는 지질특성상 각종 토공사를 시행할 때 암반 절취가 필수적이다. 그러나 소음진동 규제법의 강화, 각종 건설민원 발생 및 안전관리를 강화하기 위하여 종래에 해오던 일반발파(대발파)공법을 적용할 현장은 거의 없는 실정이므로, 미진동 발파공법과 진동제어 발파공법에 대한 기준품셈 및 시공기술에 대한 연구가 더욱 필요하다. 또한 종래의 미진동 발파공법의 품셈기준으로 되어있는 미진동 파쇄기(CCR, 상품명 Fine Cracker)를 사용한 발파공법은 기존의 암절취에 기술적 문제가 일부 대두되므로 이를 보완하기 위해 퇴적암 절취현장에서 미진동 파쇄기.정밀.에멀젼 화약을 사용하여 비교실험을 하였으며, 최근에 새로운 미진동 파쇄기(상품명 : Fine Cracker Plus)를 개발 시판하게 되어 이를 비교 검토하였다. 그 결과 일축 압축강도 $1623~2060kg/\textrm{cm}^2$의 경암 내지 극경암에서도 양호한 발파효과를 볼 수 있었다.

• Macromolecular Research
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• v.13 no.1
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• pp.30-38
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• 2005

Sulfur-cured gum natural rubber vulcanizates were devulcanized using two different concentrations of diallyl disulfide. The devulcanization process was performed at $110^{\circ}C$ min in an open two-roll cracker-cum-mixing mill. Natural rubber vulcanizates having various sulfur/accelerator ratios were used to study the cleavage of monosulfide, disulfide, and polysulfide bonds. The properties of devulcanized natural rubber increased upon increasing the disulfide concentration and the mechanical properties of the revulcanized natural rubber increased upon decreasing the sulfur content in the original rubber vulcanizates. The scorch time and the maximum state of cure both increased when the ground vulcanizates were treated with higher amounts of disulfide. TGA and DMA were conducted to study the effects of the devulcanization on the thermal stability and the $T_g$ behavior of the vulcanizates. SEM analysis was conducted to study how the failure mechanism was affected by the devulcanization process. It was possible to recover $70-80\%$ of the original gum rubber properties by using this process. From IR spectroscopic analysis, we observed that the oxidation of the main chains did not occur during high-temperature milling.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.150-155
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• 1997

The twenty strains of Lactobacillus genus were tested for the optimal sponge fermentation of soda cracker. The six strains such as L. brevis, L. delbrueckii, L. fermentum, L. leichmanii, L. plantarum and L. sanfrancisco were selected because these strains did not smell off-flavor and showed the high value of TTA (total titrable acidity) after the fermentation. The selected strains consisted of the five strains of L. brevis, L. delbrueckii, L. fermentum, L. leichmanii and L. plantarum that mainly inhabited soda clacker and L. sanfrancisco that existed in San Francisco bread. The lactic acid bacteria were inoculated to the medium containing 10% wheat flour and then pH, TTA, acetic acid and lactic acid were measured during the sponge fermentation. The four strains of L. brevis, L. delbrueckii, L. fermentum and L. plantarum were used for the mixed lactic acid bacteria of sponge fermentation because the TTAs of L. brevis, L. fermentum and L. plantarum were higher than those of other lactic acid bacteria and L. delbrueckii rapidly produced organic acids and a large amount of acetic acid. Among the combination of L. brevis, L. fermentum, L. delbrueckii and L. plantarum, the mixed lactic acid bacteria of L. brevis, L. fermentum and L. plantarum showed the highest TTA, the lowest pH and the largest amount of acetic acid. Therefore, the mixed lactic acid bacteria of L. brevis, L. fermentum and L. plantarum were used for optimal sponge fermentation of soda cracker.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.69.4-69
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• 2002

1. Introduction 2. Fundamental Model 3. Simulation Procedure 4. Results 5. Conclusion