• 대한조선학회지
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• 제27권1호
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• pp.45-56
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• 1990

본 해석에서는 압력용기를 설계하기 위하여 복합적층된 원통형 구각의 비선형 해석을 유한요소법으로 수행하였다. 적층순서의 변화에 따라 최소변위 또는 최대압력을 갖는 최적의 적층구조를 얻기 위하여 8절점 Isoparametric 격하요소를 사용하며 구조요소의 비선형거동은 Total Lagrangian 수식과 하중증분법을 적용하여 해석하며 평형반복수렴은 Newton-Raphson Method를 이용하였다. 선형해석의 경우에 9가지 적층구조를 선정하여 하중조건이 내압일때 최소변위를 나타내는 적층구조를 조사한 결과 $[50^{\circ}/-50^{\circ}]$의 최적구조를 구하였고 적층순서를 $[{\theta}^{\circ}/{-\theta}^{\circ}]$로 하여 비선형해석과 동시에 Quadratic Failure Criteria를 적용하였을 때 하중조건이 외압만을 고려하는 상태에서도 $\theta=50^{\circ}$가 최소 변위비를 나타내었고 외압과 축하중을 동시에 고려한 상태에서는 $\theta=90^{\circ}$였다.

• 한국항해항만학회지
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• 제33권1호
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• pp.27-33
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• 2009

압축하중 및 횡하중의 조합하중을 받는 연속 보강판넬의 좌굴강도 및 최종강도의 평가는 선체구조 안정성을 재고하는데 아주 중요한 요소이다. 예를들면, 선박의 공창 상태에서 선체외판은 수압하중에 의해서 파생되는 횡방향 면내 압축하중과 선체외판에 작용하는 횡하중은 대표적인 하중 성분이다. 지금까지의 대부분의 연구 결과들은 실험테스트 및 이론석인 접근 그리고 수치계산 방법에 의해서 수행되었으며, 단일 판 또는 보강판의 조합하중에 대한 많은 업적들이 있다. 그러나, 이들 중 대부분의 연구는 종방향 면내 압축하중과 횡하중에 의한 연구결과가 대부분이며, 횡방항 면내 압축하중과 횡하중에 대한 결과들은 상대적으로 많지가 않다. 게다가 이전의 연구들은 주고 네변 단순지지된 판부재를 고려하였으나, 실제의 구조를 고려해보면, 횡방향 프레임과 종방향 거더들이 교차되어 있는 보강 판넬 구조이다. 본 연구는, 3척의 실적선에서 얻은 이중저 판넬 모델을 적용하고, 횡하중의 크기를 변수로 한 탄소성대변형 유한요소해석을 수행하였다. 이러한 여러 가지 수치 해석을 통하여, 횡하중의 크기 변화에 대한 영향과 횡방향 압축하중이 작용하는 붕괴 매커니즘에 대해서 고찰하였다.

• Composites Research
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• 제13권1호
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• pp.69-77
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• 2000

본 논문에서는 크기가 일정한 비증분 하중과 크기가 커서 증분이론을 사용해야만 하는 증분하중이 동시에 가해지는 구조물의 비선형 해석을 위한 수정 호길이법을 제시한다. 수정된 호길이법에서는 비선형 계산을 수행할 때 증분하중에 의한 변위와 비증분 하중에 의한 변위를 구분하여 처리하게 된다. 제안된 방법의 타당성은 내압, 외압 및 압축하중을 받는 쉘 구조물의 비선형 거동에 대한 기존 결과와의 비교를 통해 검토하였다. 또한 비증분 하중과 증분하중이 함께 가해지는 대표적인 경우로서, 일정 횡압력과 축방향 증분 압축하중을 동시에 받는 쉘 구조물의 비선형 좌굴거동에 대한 인자연구를 수행하였다.

• 한국의류산업학회지
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• 제22권5호
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• pp.561-569
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• 2020

In this study, the dyeing of Chrysanthemum indicum Linne alone and the combined dyeing of Chrysanthemum indicum Linne and onion shell were first performed to compare dyeing properties. A combination extract of Chrysanthemum indicum Linne and onion shell can be expected to improve coloration. A Hanbok design for children used a natural dyeing fashion dyeing method to make the Chrysanthemum pattern. Chrysanthemum indicum Linne is a type of wild chrysanthemum with various medicinal effects for headache and stress relief, skin diseases, insomnia and depression. Widely used onion shells have medicinal properties that help prevent and treat various adult diseases. The colors of silk dyed exclusively by Chrysanthemum indicum Linne, and the colors of silk dyed by Chrysanthemum indicum Linne and onion shell extract are yellow; in addition, silk dyed by Chrysanthemum indicum Linne and onion shell extracts were almost all unchanged. Four hanboks, which are comfortable for children to wear and use, were produced using Chrysanthemum indicum Linne and onion shell extracts. If children wear hanbok fashion products with auspicious patterns, they can provide a chance to simultaneously experience the traditional symbolism of Korean patterns and culture. In addition, it is expected to develop pride in traditional dress culture.

• 천문학회지
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• 제37권4호
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• pp.211-216
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• 2004

We present the results of an H I aperture synthesis mosaic of the Large Magellanic Cloud (LMC), made by combining data from 1344 separate pointing centers using the Australia Telescope Compact' Array (ATCA) and the Parkes multibeam receiver. The resolution of the mosaiced images is 50" (<15 pc, using a distance to the LMC of 55kpc). This mosaic, with a spatial resolution .15 times higher than that which had been previously obtained, emphasises the turbulent and fractal structure of the ISM on the small scale, resulting from the dynamical feedback of the star formation processes with the ISM. We also have done a widefield panoramic survey of H$\alpha$ emission from the Magellanic Clouds with an imager mounted on the 16-inch telescope at Siding Spring Observatory. This survey produced H$\alpha$ images which are equal to the ATCA survey in area coverage and resolution. This survey allows us to produce a continuum-subtracted image of the entire LMC. In contrast with its appearance in the H$\alpha$ image, the LMC is remarkably symmetric in H I on the largest scales, with the bulk of the H I residing in a disk of diameter 8. $^{\circ}4$ (7.3 kpc) and a spiral structure is clearly seen. The structure of the neutral atomic ISM in the LMC is dominated by H I filaments combined with numerous shells and holes.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2617-2620
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• 2009

Using Coulomb-Yukawa like correlated interaction potentials of integer and noninteger indices the series expansion formulae in terms of multicenter overlap integrals of three complete orthonormal sets of ${\psi}^{\alpha}$‒exponential type orbitals and linear combination coefficients of molecular orbitals are established for the potential of electrostatic field produced by the charges of molecule, where $\alpha$ = 1, 0, ‒1, ‒2,${\cdots}$. The formulae obtained can be useful for the study of interaction between atomic--molecular systems containing any number of closed and open shells when the ${\psi}^{\alpha}$‒exponential type basis functions and Coulomb-Yukawa like correlated interaction potentials are used in the Hartree-Fock-Roothaan and explicitly correlated approximations. The final results are valid for the arbitrary values of parameters of correlated interaction potentials and orbitals. As an example of application, the calculations have been performed for the potential energy of interaction between electron and molecule $H_2O$ using combined Hartree-Fock-Roothaan equations suggested by the author.

• 한국수산과학회지
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• 제49권4호
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• pp.436-444
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• 2016

Clamshells, which comprise more than 50% of a clam’s weight, are a major byproduct of the clam industry and are mainly composed of insoluble calcium carbonate. This study investigates the use of clamshells as a natural calcium resource. Highly soluble powdered calcium lactate (LCCL) was prepared from the calcined powdered shells of littleneck clams (LCCP) using response surface methodology (RSM) to predict optimum conditions. These conditions, as derived from pH, solubility, and yield of 11 LCCLs manufactured according to the RSM model, were 1.80 M lactic acid and 1.13 M LCCP. The actual values of pH (6.98), solubility (93.99%), and yield (351.23%) under the optimized conditions were as predicted. The derived LCCL exhibited a strong buffering capacity in the range of pH 2.78-3.90 when combined with less than 2 mL of 1 N HCl. The ranges of calcium content and solubility of LCCL were 7.7-17.5 g/100 g and 96.6-98.9%, respectively. Fourier transform infrared spectroscopy (FT-IR) of the LCCL identified it as calcium lactate pentahydrate, and field emission scanning electron microscopy (FESEM) revealed an irregular and rod-like microstructure. These results confirm the potential use of clamshells, converted to highly soluble organic acid calcium, as an additive to enhance calcium content in food ingredients.

• 자원리싸이클링
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• 제11권2호
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• pp.45-51
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• 2002

본 연구는 수산폐기물인 폐굴껍질과 우리나라에 넓게 분포되어 있는 황토를 이용하여 응집제를 제조하기 위한 것으로서 응집제원료의 성분조사 결과, 폐굴껍질은 CaO성분이 55.43(wt%)로 가장 많이 함유되어 있었고, 황토는$ SiO_2$가 45.30(wt%)로 주성분임을 알 수 있었다. 폐굴껍질 내의 CaO순도를 높이기 위해 $900^{\circ}C$에서 2시간동안 소성 하였으며. ball mill을 사용하여 0.074 mm(200mesh)로 분쇄 하였다. 소성된 폐굴껍질 분말과 황토 분말을 각각 6:4, 7:3, 8:2, 9: 1의 비율로 혼합하여 응집제를 제조하였다 또한 제조된 응집제와 화학 소석회와의 비교실험을 통해 화학 소석회의 대체 가능성을 확인하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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• pp.482-493
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• 2005

Biomass is originally photosynthesized from inorgainic compounds such as $CO_2$, minerals, water and solar energy. Recent studies have shown that anaerobic bacteria have the ability to convert recalcitrant biomass such as cellullosic or chitinoic materials to useful compounds. The biomass containing agricultural waste, unutilized wood and other garbage is expected to utilize as feed, food and fuel by microbial degradation and other metabolic functions. In this study we isolated several anaerobic, cellulolytic and chitinolytic bacteria from rumen fluid, compost and soil to study their related enzymes and genes. The anaerobic and cellulolytic bacteria, Clostridium thermocellum, Clostridium stercorarium, and Clostridium josui, were isolated from compost and the chitinolytic Clostridium paraputrificum from beach soil and Ruminococcus albus was isolated from cow rumen. After isolation, novel cellulase and xylanase genes from these anaerobes were cloned and expressed in Escherichia coli. The properties of the cloned enzymes showed that some of them were the components of the enzyme (cellulase) complex, i.e., cellulosome, which is known to form complexes by binding cohesin domains on the cellulase integrating protein (Cip: or core protein) and dockerin domains on the enzymes. Several dockerin and cohesin polypeptides were independently produced by E. coli and their binding properties were specified with BIAcore by measuring surface plasmon resonance. Three pairs of cohesin-dockerin with differing binding specificities were selected. Two of their genes encoding their respective cohesin polypeptides were combined to one gene and expressed in E. coli as a chimeric core protein, on which two dockerin-dehydrogenase chimeras, the dockerin-formaldehyde dehydrogenase and the dockerin-NADH dehydrogenase are planning to bind for catalyzing $CO_2$ reduction to formic acid by feeding NADH. This reaction may represent a novel strategy for the reduction of the green house gases. Enzymes from the anaerobes were also expressed in tobacco and rice plants. The activity of a xylanase from C. stercorarium was detected in leaves, stems, and rice grain under the control of CaMV35S promoter. The digestibility of transgenic rice leaves in goat rumen was slightly accelerated. C. paraputrificum was found to solubilize shrimp shells and chitin to generate hydrogen gas. Hydrogen productivity (1.7 mol $H_2/mol$ glucos) of the organism was improved up to 1.8 times by additional expression of the own hydrogenase gene in C. paraputrficum using a modified vector of Clostridiu, perfringens. The hydrygen producing microflora from soil, garbage and dried pelletted garbage, known as refuse derived fuel(RDF), were also found to be effective in converting biomass waste to hydrogen gas.