• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.611-612
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.83-84
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• 2011

• 한국기계가공학회지
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• 제21권2호
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• pp.79-86
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• 2022

Numerous fabrication techniques have been used to mimic cylindrical natural tissues, such as blood vessels, tendons, ligaments, and skeletal muscles. However, most processes have limitations in achieving the biomimetic properties of multilayered and porous architectures. In this study, to embrace both features, a novel self-assembly method was proposed using electrospun microfibrous sheets. A bilayer microfibrous structure, comprising two sheets with different internal stresses, was fabricated by electrospinning a polycaprolactone (PCL) sheet on a uniaxially stretched thermoplastic polyurethane (TPU) sheet. Then, by removing the stretching tension, the sheet was rolled into a hollow cylindrical structure with a specific internal diameter. The internal diameter could be quantitatively controlled by adjusting the thickness of the PCL sheet against that of the TPU sheet. Through this self-assembly method, biomimetic cylindrical structures with multilayer and porous features can be manufactured in a stable and controllable manner. Therefore, the resulting structures may be applied to various tissue engineering scaffolds, especially vascular and connective tissues.

• 대한기계학회논문집A
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• 제36권1호
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• pp.1-7
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• 2012

이 논문에서는 최소의 배터리를 소비하여 물고기 로봇을 구동하고, 물고기와 같은 유연한 운동을 할 수 있는 생체 모방(biomimetic) 물고기 로봇의 설계, 제작, 제어에 관하여 제안 하였다. 두 개 모터를 적용하여 물고기와 같이 유연하게 움직일 수 있는 방법을 제시 하였다. 중성 부력을 유지하는 방법과 빠르게 잠영하고, 방향을 전환 하기 위한 방법을 제시 하였다. 로봇 물고기의 꼬리는 유연한 움직임을 만들기 위하여 폴리머 재질을 사용하여 만들었다. 꼬리 내부는 관절과 강선으로 구성된다. 로봇 물고기에 척추에 해당하는 우레탄 골격과 관절을 이루는 핀에 연결된 강선을 당겨 꼬리에 정현파 명령을 주어 물고기와 비슷한 유영을 할 수 있도록 하였으며, 부력 조절 장치를 설치하였으며, 이 부력 조절 장치를 이용하여 물고기 로봇이 상승, 하강을 할 수 있도록 하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 추계학술대회논문집
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• pp.159-163
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• 2009

In this paper, the fluid dynamic forces and performances of a moving airfoil in the low Reynolds number flow is addressed. In order to calculate the necessary propulsive force for the moving airfoil in a low Reynolds number flow, a lattice-Boltzmann method is used. The critical Reynolds and Strouhal numbers for the thrust generation are investigated for the four propulsion types. It was found that the Normal P&D type produces the largest thrust with highest efficiency among the investigated types. The leading edge of the airfoil has an effect of deciding the force production types, whereas the trailing edge of the airfoil plays an important role in augmenting or reducing the instability produced by the leading edge oscillation. It is believed that present results can be used to decide the optimal propulsion devices for the given Reynolds number flow.

• Korean Chemical Engineering Research
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• 제43권2호
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• pp.202-205
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• 2005

GoAgg 생체모방계 산화반응시스템을 이용하여 상온, 상압에서 시크로헥산을 산화 반응하여 시크로헥산올과 시클로헥산온 제조를 위한 연구를 수행하였다. 반응속도론적 연구를 수행하였으며 리간드로 카르복실기를 포함하는 picolinic acid를 사용한 경우 철 촉매만 사용한 경우에 비해 15배 이상의 활성이 증가하였다. 특히 피리딘환이나 이미다졸환에 ortho 위치에 카르복실기를 포함한 경우 meta, para 위치보다 반응성이 크게 증가하였다. 이 결과로부터 새로운 매커니즘을 제안하였다.

• 한국세라믹학회지
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• 제45권10호
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• pp.638-643
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• 2008

Biomimetic apatite formation and deposition behaviors of Ti-6Al-7Nb and Ti-6Al-4V plates in simulated body fluids(SBF) under various conditions were examined. In case of regular samples without collagen treatments the weight gain due to apatite precipitation on the surface in Ti-6Al-4V was found to be higher than in Ti-6Al-7Nb. In case of collagen-coated samples, the weight gain in Ti-6Al-4V continued to be higher than in Ti-6Al-7Nb, but the difference between the two became smaller. Both Ti-6Al-7Nb and Ti-6Al-4V samples with collagen coating exhibited an appreciable increase of weight gain, which may be caused by the interaction between collagen and $Ca^{+2}$ ions. The weight gain was found to be not much affected by the addition of collagen to SBF. The ill-defined granular structure in the presence of collagen can be associated with the increasing volume fraction of amorphous calcium phosphate.

• Journal of Mechanical Science and Technology
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• 제20권11호
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• pp.1914-1919
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• 2006

Recently, the microrobots powered by biological muscle actuators were proposed. Among the biological muscle actuators, frog muscle is well known as a good muscle actuator and has a large displacement, actuation forces and piezoelectric properties. Therefore, for the application of the biomimetic microrobot, this paper reports the electromechanical properties of frog muscle. First of all, the experimental setup has been established for measuring generative force of the frog muscle. Through the various electrical stimulating inputs to the frog muscle, we measured the contractile force of the frog muscle. From the measuring results, we found that the actuating contractile force responses of the frog muscle are determined by the amplitude, frequency, duty ratio, and wave form of the stimulation signal. This study will be beneficial for the development of the microrobot actuated by frog muscle.

• 한국재료학회지
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• 제15권11호
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• pp.690-696
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• 2005

The ultrastructure ore of a nanostructured apatite film nucleated from solution was studied to gain insights into that of bone minerals which is the most important constituent to sustain the strength of bones. Needle-shaped apatite crystal plates with a bimodal size distribution $(\~100\;to\;\~1000 nm)$ were randomly distributed and they were found to grow parallel to the c-axis ([002]), driven by the reduction of surface energy. Between these randomly distributed needle-shaped apatite crystals which are parallel to the film, apatite crystals (20-40nm) with the normal of the grains quasi-perpendicular to the c-axis were observed. These observations suggest that the apatite film is the interwoven structure of apatite crystals with the c-axis parallel and quasi-perpendicular to the fan. In some regions, amorphous calcium phosphate, which is a precursor of apatite, was also observed. In the amorphous phase, small crystalline particle with the size of 2-3 nm were observed. These particles were quite similar, in size and shape, to those observed in the femoral trabecular bone, suggesting the nucleation of apatites by a biomimetic process in vitro is similar to that in vivo.

• 한국전산유체공학회지
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• 제15권2호
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• pp.41-46
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• 2010

In this paper, the fluid dynamic forces and performances of a moving airfoil in the low Reynolds number flow is addressed. In order to simulate the necessary propulsive force for the moving airfoil in a low Reynolds number flow, a lattice-Boltzmann method is used. The critical Reynolds and Strouhal numbers for the thrust generation are investigated for the four propulsion types. It was found that the Normal P&D type produces the largest thrust with the highest efficiency among the investigated types. The leading edge of the airfoil has an effect of deciding the force production types, whereas the trailing edge of the airfoil plays an important role in augmenting or reducing the instability produced by the leading edge oscillation. It is believed that present results can be used to decide the optimal propulsion types for the given Reynolds number flow.