• Steel and Composite Structures
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• 제18권2호
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• pp.305-324
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• 2015

In this study, two common types of laterally supported castellated beams are considered as design problems: beams with hexagonal openings and beams with circular openings. The main goal of manufacturing these beams is to increase the moment of inertia and section modulus, which results in greater strength and rigidity. These types of open-web beams have found widespread use, primarily in buildings, because of great savings in materials and construction costs. Hence, the minimum cost is taken as the design objective function and the Colliding Bodies Optimization (CBO) method is utilized for obtaining the solution of the design problem. The design methods used in this study are consistent with BS5950 Part 1 and Part 3, and Euro Code 3. A number of design examples are considered to optimize by CBO algorithm. Comparison of the optimal solution of the CBO algorithm with those of the Enhanced Charged System Search (ECSS) method demonstrate the capability of CBO in solving the present type of design problem. It is also observed that optimization results obtained by the CBO algorithm for three design examples have less cost in comparison to the results of the ECSS algorithm. From the results obtained in this paper, it can be concluded that the use of beam with hexagonal opening requires smaller amount of steel material and it is superior to the cellular beam from the cost point of view.

• 펄프종이기술
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• 제45권1호
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• pp.75-82
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• 2013

The traditional Hanji-making was confronted with lots of industrial disadvantages and economic problems, due to the original hand-made process. Recently, the studies on the automation of overall Hanji manufacturing process is carried out by applying the commercial chemical pulping method in order to expand industrial application or efficiency of non-wood fibrous materials. However, the application of commercial pulping methods to the bast tissues of paper mulberry leads to the chemical and mechanical deterioration of cellulosic fibers. In this study, the optimal cooking method using the bast parts of paper mulberry produced by an auto-scraping device was applied to minimize the damage of fiber strength for the paper yarn manufacture. The pre-steaming treatment and alkaline pulping systems were evaluated in removal efficiency of lignin and pectin materials within the bast tissue of paper mulberry. With the application of pre-steaming treatment and 2 stage pulping system using potassium carbonate and then sodium hydroxide, kappa values were decreased two times more in lignin removal than the single stage of pulping method. It was also identified from SEM images and ATR-FTIR spectra that the pectin components within cellular structure of bast tissue were easily removed and the debarked bast parts by a auto-scraping device were easily defiberized by 2-stage pulping sequence using potassium carbonate/sodium hydroxide pulping system.

• 분석과학
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• 제27권5호
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• pp.248-253
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• 2014

이 연구는 Mn과 Pb의 노출이 면역체계에 미치는 영향을 파악하고자 하였다. 연구대상자는 남성 근로자 42 명으로, 대상자 중 13명은 사무직 근로자(실험군 I), 21 명은 제조업 사업장 근로자(실험군 II), 8명은 용접 작업자(실험군 III)였다. 대상자의 혈액 중 Mn과 Pb 농도는 실험군별로 유의한 차이를 보였다. 실험군 I 대상자의 CD19+와 total lymphocytes 농도는 기타의 실험군 대상자에서보다 유의하게 높았으나 다른 T lymphocytes subpopulation의 농도는 차이가 없었다. Mn과 Pb 농도는 T lymphocytes subpopulation과 음의 상관관계를 보였으나, Mn은 CD4+CD45RO+와 자연살해세포를 제외한 T lymphocytes subpopulation과 유의한 음의 상관관계를 보였다. Pb 농도는 단지 total lymphocytes 농도와 유의한 음의 상관관계를 보였다. 이 연구에서 Mn과 Pb의 직업적인 노출은 세포성면역계에 영향을 미칠 수 있음을 제시하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.202-202
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• 2011

The research of 3-dimensional (3-D) scaffold for tissue engineering has been widely investigated as the importance of the 3-D scaffold increased. 3-D scaffold is needed to support for cells to proliferate and maintain their biological functions. Furthermore, its architecture defines the shape of the new bone and cartilage growth. Polycaprolactone (PCL) has been one of the most promising materials for fabricating 3-D scaffold owing to its excellent mechanical property and biocompatibility. However, there are practical problems for using it, in vitro and in vivo; extracellular matrix components and nutrients cannot penetrate into the inner space of scaffold, due to its hydrophobic property, and thus cell seeding and attachment onto the inner surface remain as a challenge. Thus, the surface modification strategy of 3-D PCL scaffold is prerequisite for successful tissue engineering. Herein, we utilized a mussel-inspired approach for surface modification of 3-D PCL scaffold. Modification of 3-D PCL scaffolds was carried out by simple immersion of scaffolds into the dopamine solution and stimulated body fluid, and as a result, hydroxyapatite-immobilized 3-D PCL scaffolds were obtained. After surface modification, the wettability of 3-D PCL scaffold was considerably changed, and infiltration of the pre-osteoblastic cells into the 3-D scaffold followed by the attachment onto the surface was successfully achieved.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2430-2434
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• 2005

Automatic FPC punching instrument for the improvement of working condition and cost saving is introduced in this paper. FPC(flexible printed circuit) is used to detect the contact position of K/B and button like a cellular phone. Depending on the quality of the printed ink and position of reference punching point to the FPC, the resistance and current are varied to the malfunctioning values. The size of reference punching point is 2mm and the above. Because the punching operation is done manually, the accuracy of the punching degree is varied with operator's condition. Recently, The punching accuracy has deteriorated severely to the 2mm punching reference hall so that assembly of the K/B has hardly done. To improve this manual punching operation to the FPC, automatic FPC punching system is introduced. Precise mechanical parts like a 5-step stepping motor and ball screw mechanism are designed and tested and low cost PC camera is used for the sake of cost down instead of using high quality vision systems for the FA. 3D Mechanical design tool(Pro/E) is used to manage the exact tolerance circumstances and avoid design failures. Simulation is performed to make the complete vision based punching machine before assembly, and this procedure led to the manufacturing cost saving. As the image processing algorithms, dilation, erosion, and threshold calculation is applied to obtain an exact center position from the FPC print marks. These image processing algorithms made the original images having various noises have clean binary pixels which is easy to calculate the center position of print marks. Moment and Least square method are used to calculate the center position of objects. In this development circumstance, Moment method was superior to the Least square one at the calculation of speed and against noise. Main control panel is programmed by Visual C++ and graphical Active X for the whole management of vision based automatic punching machine. Operating modes like manual, calibration, and automatic mode are added to the main control panel for the compensation of bad FPC print conditions and mechanical tolerance occurring in the case of punch and die reassembly. Test algorithms and programs showed good results to the designed automatic punching system and led to the increase of productivity and huge cost down to law material like FPC by avoiding bad quality.

• Applied Biological Chemistry
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• 제48권4호
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• pp.382-387
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• 2005

본 연구는 게르마늄 강화 효모의 제조 공정을 위한 최적의 조건을 잡고 제조된 게르마늄 강화 효모 내의 게르마늄의 결합 상태 확인을 목적으로 하였으며, 그 결과는 다음과 같다. 균체와 게르마늄 용액 혼합 비율 1 : 0.5(50%)로 하여 균체와 게르마늄 배양시 최적 조건인 pH 6.5, 온도 $35^{\circ}C$ 그리고 배양 시간은 20시간 배양하는 것이 높은 함량의 게르마늄을 효모 균체 내로 유입시켜 게르마늄 강화 효모를 생산하였으며, 이의 배양 과정을 통해 생산된 게르마늄 강화 효모는 배양 과정 동안의 구조적 변화에 의해 효모 내에 유입된 무기 형태인 $GeO_2$ 게르마늄과는 다른 구조를 형성하고 있었다. 또한 NMR 및 FTIR 실험을 실시한 결과 게르마늄 강화 효모의 발효 과정에 첨가한 무기 형태의 $GeO_2$가 배양 과정 동안 균체 내에서 게르마늄이 유입되는 과정에서 게르마늄이 단백질(혹은 펩타이드)과 결합하여 구조에 변화를 형성하였으며, 인공위액 안에서 투석막을 이용한 투석 전후에 따른 게르마늄 총량에서 투석 전후에 따른 차이가 나타나지 않았다. 따라서 게르마늄 강화 효모는 생합성 기법을 이용하여 게르마늄을 강화한 유기 게르마늄 생산방법으로 배양 과정을 통해 구조적으로 안전한 유기 게르마늄을 형성하여 인공위액 조건에서도 해리되지 않는 것으로 보여지며, 각종 암, 성인병의 예방과 치료, 인체 면역력의 증진 등 건강 증진을 위한 새로운 기능성 원료로의 활용이 기대되며, 이에 대한 지속적인 연구가 사료된다.