• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1104-1108
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• 1999

In this study it was focused that if the chrome could be removed in the shaving dust, the reusable protein resource could be recycled from the shaving dust. As the chrome forms a Cr-collagenate by cross linking of collagen in the shaving dust, the dust was steeped for swelling and plumping by $Ca(OH)_2$ solution and then chromium in dust was resolved out by $H_2SO_4$ solution in the first stage process. In the second stage one, dust was swelled and plumped by NaOH solution and then the chromium in dust was oxygenated to a hexavalent chrome, which has high solubility in $H_2O_2$ solution. And then the chromium was removed byt he steeping of $H_2SO_4$ solution as the last process. The first stage process was consisted of the sequential steeping of 3%-$Ca(OH)_2$ and $0.8%-H_2SO_4$. In the second stage the total chrome was effectively removed by the sequential steeping of 0.1%-NaOH, $3%-H_2O_2$ and $1%-H_2SO_4$. In the completely dechromated dust, the humidity was measured as 10.68% and the crude protein was contained by 79.81%. Steeping solutions were reused 3 times for chrome removal process, the chrome was entirely removed in shaving dust.

• Journal of The Korean Association For Science Education
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• v.37 no.5
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• pp.775-785
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• 2017

The purpose of this study is to analyze the outcome of 'The second plan for identifying and nurturing of science-gifted student' and investigate the implications for the third plan. 'The second plan for identifying and nurturing of science-gifted student' was made for the promotion of science-gifted education from 2013 to 2017. This plan is composed of three strategies with 25 sub-projects: a systematic identification of science-gifted students with potential, an activation of creative and integrated science-gifted education and an establishment of optimized science education supporting system. We supposed six implications through the investigation of the performance analysis of each sub-project. First, the third plan should be composed of projects to be able to be supported directly. Second, the paradigm shift is needed from quantitative expansion to qualitative expansion. Third, third plan should include a special support for profoundly gifted students. Fourth, a specialization plan for science-gifted institute is required. Fifth, it is necessary to establish a camp or residential type gifted institute. Sixth, it is needed to have a quality management of science-gifted programs and MOOC (massive open online course) on science-gifted programs are needed.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.106-113
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• 2002

This research was performed to investigate the effect of moulding conditions on properties of the table top for student desk manufactured by wood waste materials. The table top manufactured using the mat mixed properly with fine particles and coarse particles generally showed better physical properties than those manufactured using either fine particles or coarse particles did/ Especially, highest performance for overlaying was observed when fine particles were used for face layer and coarse particles were used for core layer. The internal bond (IB) strength, the bending strength and thickness swelling increased with the increase of density. Most of physical properties were improved with the increase of hot pressing temperature. The best physical properties were found at 190℃ when the first hot pressing and the second hot pressing times were two minutes. However, the effect of the second hot pressing time of two minutes on the physical properties was not markedly different from that of one minute. This result suggests that the second hot pressing time of one minute is enough to increase the productivity in manufacturing the table top with the least decrease of the physical properties.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.394-400
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• 2023

In this study, the tuning phenomena, gas storage capacity, and thermal expansion behaviors of binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates were investigated for the potential applications of clathrate hydrates to gas storage. To understand the tuning behaviors of binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates, ¹³C solid-state NMR spectroscopy was used, and the results confirmed that maximum tuning factors for the binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates were achieved at 0.5 mol% and 1.0 mol% of guest concentration, respectively. The gas storage capacity of binary (cyclopentylamine + CH₄) and (cyclopropylamine + CH₄) clathrate hydrates were also checked, and the results showed the CH₄ capacity of our hydrate systems was superior to that of binary (tetrahydrofuran + CH₄) and (cyclopentane + CH₄) clathrate hydrates. The synchrotron diffraction patterns of these hydrates collected at 100, 150, 200, and 250 K confirmed the formation of a cubic Fd-3m hydrate. In addition, the lattice constant of clathrate hydrates with cyclopentylamine and methane were larger than that with cyclopropylamine and methane due to the effects of molecular size and shape.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6C
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• pp.259-266
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• 2009

The steel pipe of steel-concrete composite piles increases the pile strength and induces the ductile failure by constraining the deformation of the inner concrete. In this research, the numerical models and the related input parameters were analyzed to simulate the axial load-movement relations, which were obtained from the compression loading tests for the cylindrical specimens of the steel pipe, the concrete, and the steel-concrete composite. As the results, the behavior of the steel pipe was simulated by the von-Mises model and that of the concrete by the strain-softening model, which decreases cohesion and dilation angles as the function of plastic strains. In addition, the reinforcing bars in the concrete were simulated by applying the yielding moment and decreasing the sectional area of the bars. The applied numerical models properly simulated the yielding behavior and the reinforcement effect of the steel-concrete composite piles. The parametric study for the real-size piles showed that the material strength of the steel-concrete composite pile increased about 10% for the axial loading and about 20~45% for the horizontal loading due to the reinforcement effect by the surrounding steel pipe pile.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.785-791
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• 2023

Risk management is essential for preventing accidents arising from uncertainties in TBM tunnel projects, especially concerning managing the risk of TBM tunnel collapse, which can cause extensive damage from the tunnel face to the ground surface. In addition, prioritizing risks is necessary to allocate resources efficiently within time and cost constraints. Therefore, this study aimed to establish a TBM risk database through case studies of TBM accidents and determine a risk priority for TBM tunnel collapse using the Bayes theorem. The database consisted of 87 cases, dealing with three accidents and five geological sources. Applying the Bayes theorem to the database, it was found that fault zones and weak ground significantly increased the probability of tunnel collapse, while the other sources showed low correlations with collapse. Therefore, the risk priority for TBM tunnel collapse, considering geological sources, is as follows: 1) Fault zone, 2) Weak ground, 3) Mixed ground, 4) High in-situ stress, and 5) Expansive ground. In practice, the derived risk priority can serve as a valuable reference for risk management, enhancing the safety and efficiency of TBM construction. It provides guidance for developing appropriate countermeasure plans and allocating resources effectively to mitigate the risk of TBM tunnel collapse.

• Tunnel and Underground Space
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• v.10 no.2
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• pp.180-195
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• 2000

Grouting has been practiced as a reliable technique to improve the mechanical properties of rock mass. But, the study of ground improvement by greeting is rare especially in jointed rock mass. In this study, joint compression test and direct shear test were performed on pure rock joint and cement milk grouted rock joint to examine the grouting effect on the property of rock joint. In the pure rock joint compression test, joint closure varied non-linearly with normal stress. But after cement milk grouting, the normal deformation characteristics of the joint was linear at the low normal stress level. As normal stress increased. deformation of the sample rapidly increased due to the stress concentration at the joint asperities. Peak shear strength of the grouted joint in low normal stress was higher than that of non-grouted joint due to the cohesion, decreased exponetially as the grout thickness increased. Thus after cement milk grouting, the failure envelope modified to a curve that has cohesion due to grout material hydration with decreased friction angle. Shear stiffness and peak dilation angle of the grouted joint decreased as the grout thickness increased. The peak shear strength from the direct shear test on grouted rock joint was represented by an empirical equation as a fuction of grout thickness and roughness mean amplitude.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.66.1-66.1
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• 2011

반도체를 비롯하여 LCD, OLED와 같은 디스플레이 (FPD: Flat Panel Display) 분야는 국가 선도 사업으로써 발전을 거듭해오고 있다. 하지만 기술의 성숙도가 높아짐에 따라 최근 중국과 대만 업체와의 경쟁이 심화되고 있으며, 더불어 환경문제가 큰 이슈로 떠오르고 있어 신기술 개발을 통한 생산 수율 향상 및 친환경 공정 개발의 중요성이 커지고 있다. 반도체, 디스플레이 공정에서 생산 수율 저하의 주요 원인으로써 공정 중 발생하는 미세 오염 입자를 들수 있다. 반도체 및 디스플레이 공정에서 세정 기술은 전체 기술의 30% 이상을 차지하며 생산 수율 및 제품의 품질에도 큰 영향을 주는 공정이다. 세정 공정은 일반적으로 습식 세정 공정이 낮은 공정비용을 바탕으로 널리 적용되어 왔으나, 기판의 대형화와 패턴의 미세화에 따라 정밀한 세정 스펙이 요구되며 더불어 막대한 양의 초순수와 화학액의 사용으로 인한 공정비용 증가와 환경 규제 강화에 따른 폐수 처리의 문제에 직면하고 있다. 이에 따라 폐수의 양을 줄이며 건조공정을 필요로 하지 않아 공정비용을 줄일 수 있는 건식 세정 공정에 대한 연구가 활발히 진행 되고 있다. $CO_2$ snow jet 세정 기술은 건식 공정으로써 $CO_2$ 가스를 특수하게 제작된 분사 노즐에서 고압으로 가스를 분사하여 이 때 발생되는 순간적인 감압에 의한 단열 팽창으로 생성된 $CO_2$ snow 입자가 기판 표면의 오염물과 물리적 충돌을 하어 세정이 이루어지는 기술이다. 특히 $CO_2$ 세정은 환경과 인체에 무해하며 공정 후 바로 승화하기 때문에 추가적인 폐수처리 공정 등이 필요하지 않고, 건식 공정으로써 수세(Rinse) 공정을 필요로 하지 않기 때문에, 공정비용을 크게 줄일 수 있으며 물반점 발생을 방지 할 수 있는 친환경 건식 공정으로써의 장점을 가지고 있다. 본 연구에서는 자체적으로 개발한 $CO_2$ snow jet을 바탕으로 하여 다양한 공정조건을 변화시켜 세정효율을 측정하는 한편, 최적화 하기 위한 연구를 진행하였으며 더불어 $CO_2$ snow의 세정력을 정량적으로 평가하기 위한 연구를 진행하였다. 실험을 통해 가장 효과적으로 $CO_2$ snow 입자를 배출 할 수 있는 공정 조건으로써 5 bar의 캐리어 가스 압력을 사용하여, 세정력에 가장 큰 영향을 줄 수 있는 분사 노즐과 기판 사이의 거리 및 분사 노즐의 각도 등을 변화시켜 각 조건에 따른 세정효율을 평가하였다. 세정 오염물은 Silica, PSL 표준 입자(Duke scientific, USA)를 정량적으로 웨이퍼에 오염 시킨 후, 파티클 스캐너(Surfscan 6500, KLA-Tencor, USA)를 이용하여 세정 전 후의 오염입자 개수 변화를 통해 정량적으로 세정효율을 평가하였다. 본 연구를 통하여 $CO_2$ snow jet를 이용한 친환경 고효율 건식 세정 공정 메커니즘을 분석하였으며, 노즐과 기판 사이의 간격 및 분사 노즐의 각도 등을 최적화 한 세정 공정을 얻을 수 있었다.

• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.277-291
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• 1983

In order to investigate the shear characteristics of earth structure after construction. Four sample soils with different gradation were selected and compacted under the optimum moisture content and the maximum dry density. And the direct shear test and the triaxial compression test were performed with those sample soils under various pre-compression loads. The results were summarized as follows; 1. With the increase of the percent passing of No. 200 sieve, the cohesion of soil increased regularly and the internal friction angle of soil decreased with slow ratio. 2. The pre-compression increased the shear strength of compacted cohesive soil. The increase of cohesion was very apparent but the internal friction angle didn't show such regular tendency. 3. With the increase of pre-compression load, the slope of stress-strain curve showed steep at the early stage of horizontal strain. The vertical strain was small at the compression stage and big at the expansion stage. 4. When the vertical stress of shear test with increase in the horizontal strain was small, stress ratio(shear stress vs. vertical stress) of sample showed the largest value and the slope of stress ratio curve showed also steep. 5. When the sample was had the same condition, the cohesion of soil showed bigger value in the triaxial compression test and the internal friction angle of soil showed bigger value in the direct shear test.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.11a
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• pp.25-29
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• 1998

본 논문은 얼굴 인식 또는 표정 인식 분야에 있어서 중요한 특징을 나타내는 얼굴과 얼굴의 주요소인 눈과 입, 눈썹의 영역 추출 및 그의 윤곽선·추출에 관한 방법을 제시한다. 얼굴요소의 영역 추출은 엣지 정보와 이진화 영상을 병합하여 이용한 프로젝션 분석을 통하여 얼굴 및 각 얼굴요소를 포함하는 최소포함사각형(MER: Minimum Enclosing Rectangle)을 추출하였다. 얼굴 영상에 관련된 윤곽선 연구에는 가변 템플릿(Deformable Template), 스네이크(Snakes: Active Contour Model)를 이용하는 연구들이 이루어지고 있는데 가변 템플릿 방법은 수행시간이 느리고 추출된 윤곽선의 모양이 획일 된 모양을 갖는 특성이 있다. 본 논문에서는 사람마다 얼굴요소의 모양의 개인차가 반영되고 빠른 수렴을 할 수 있는 스네이크 모델을 정의하여 눈, 입, 눈썹, 얼굴의 윤곽선 추출 실험을 하였다. 또한 스네이크는 초기 윤곽선의 설정이 윤곽선의 추출 곁과에 큰 영향을 미치므로, 초기 윤곽선의 설정 과정이 매우 중요하다. 본 논문에서는 얼굴 및 각 얼굴요소를 포함하는 각각의 최소 포함 사각형(MER)을 추출하고, 이 추출된 MER 내에서 얼굴 및 각 얼굴요소의 일반적인 모양을 초기 윤곽선으로 설정하는 방법을 사용하였다. 실험결과 눈, 입, 얼굴의 MER의 추출은 모두 성공하였고, 눈썹이 흐린 사람들의 경우에만 눈썹의 MER추출이 졸지 않았다. 추출된 MER을 기반으로 하여 스네이크 모델을 적용한 결과, 눈, 입, 눈썹, 얼굴의 다양한 모양을 반영한 윤곽선 추출 결과를 보였다. 특히 눈의 경우는 1차 유도 엣지 연산자에 의한 엣지 와 2차 유도 연산자를 이용한 영점 교차점(Zero Crossing)과 병합한 에너지 함수를 설정하여 보다 더 나은 윤곽선 추출 결과를 보였다. 얼굴의 윤곽선의 경우도 엣지 값과 명도 값을 병합한 에너지 함수에 의해 비교적 정확한 결과를 얻을 수 있었다.잘 동작하였다.되는 데이타를 입력한후 마우스로 원하는 작업의 메뉴를 선택하면 된다. 방법을 타액과 혈청내 testosterone 농도 측정에 응용하여 RIA의 결과와 비교하여 본 바 상관관계가 타액에서 r=0.969, 혈청에서 r=0.990으로 두 결과가 잘 일치하였다. 본 실험에서 측정된 한국인 여성의 타액내 testosterone농도는 107.7$\pm$12.0 pmol／l이었고, 남성의 타액내 농도는 274.2$\pm$22.1 pmol／l이었다. 이상의 결과로 보아 본 연구에서 정립된 EIA 방법은 RIA를 대신하여 소규모의 실험실에서도 활용할 수 있을 것으로 사려된다.또한 상실기 이후 배아에서 합성되며, 발생시기에 따라 그 영향이 다르고 팽창과 부화에 관여하는 것으로 사료된다. 더욱이, 조선의 ${\ulcorner}$구성교육${\lrcorner}$이 조선총독부의 관리하에서 실행되었다는 것을, 당시의 사범학교를 중심으로 한 교육조직을 기술한 문헌에 의해 규명시켰다.nd of letter design which represents -natural objects and was popular at the time of Yukjo Dynasty, and there are some documents of that period left both in Japan and Korea. "Hyojedo" in Korea is supposed to have been influenced by the letter design. Asite- is also considered to have been "Japanese Letter Jobcheso." Therefore, the purpose of this study is to look into the origin of the letter designs in the Chinese character culture