고분자 분리막의 대표적인 형태 중 하나인 평판형 분리막은 제조가 용이하여 실험실에서 분리막 소재 연구에서부 터 실제 상용 분리막 생산에 이르기까지 널리 활용되는 분리막의 형태이다. 정밀여과 및 한외여과 등에 사용되는 평판형의 다공성 고분자 분리막은 주로 상분리 공정을 통해 제조할 수 있으며, 여기에는 비용매 유도 및 증기 유도 상분리 공정이 활 용된다. 그러나 상분리 공정 특성상 주변 환경과 실험자에 따라 샘플 간 편차가 쉽게 발생하여 재현성의 확보가 어려운 점이 있다. 따라서 개발된 제조기술을 스케일업 및 재현성 확보를 위해 제어된 환경에서 연속식 대면적 제조가 가능한 롤투롤 제 조장치가 필요하며, 본 연구에서는 실험실 스케일의 제조기술을 나이프 및 슬롯다이 롤투롤 공정으로 스케일 업 했을 때 나 타나는 제조 환경 차이에 따른 분리막의 특성 변화를 비교하였다. 최종적으로 연속식 제조공정 인자에 대한 최적화를 통해 대면적 제조 시 분리막의 균일성을 확보하였다.

현대의 방탄 장갑은 우수한 관통 저항성을 갖추어야할 뿐만 아니라 군인과 군용차량의 기동성이 확보되어야 하기 때문에 경량화가 중요한 개발 요소가 되었다. 이종 적층 평판 구조의 방탄 장갑의 방탄 성능은 동일 중량 대비 구성 재료의 배열에 따라 달라진다. 본 논 문에서는 케블라, 초고분자량 폴리에틸렌 그리고 에바 폼으로 구성된 방탄 장갑의 적층 배열에 따른 방탄 성능을 분석한다. 구성 재료 의 두께가 5mm와 6.5mm인 두 가지 경우에서 6가지 적층 배열에 대하여 7.62 × 51mm NATO 탄환의 M80 탄을 856m/s의 속도로 충돌 시키는 피탄 해석을 수행하였다. 방탄 성능을 평가하기 위해 이종 적층 평판을 관통한 발사체의 잔류 속도와 잔류 에너지를 측정하였 다. 시뮬레이션 결과를 통해 케블라, 초고분자량 폴리에틸렌, 에바 폼의 배열 순서를 갖는 적층 구조가 동일 중량에 대해 가장 우수한 방탄 성능을 가짐을 확인하였다.

As the demand for appropriate heat dissipation measures to improve product stability and performance continues to increase and product design becomes highly integrated, research to improve heat transfer performance while maintaining the same area or size is required. In this study, the sample-shaped aluminum plate was treated as upper-coating, and the thickness of the coating was divided into 1mm, 2mm, and 3mm, respectively, and the coating material was applied with silver, copper, and graphene. The temperature condition of the heat source was set to 473K, and heat dissipation analysis was performed under natural convection. The thermal performance was compared and analyzed through temperature distribution, flow velocity distribution, and heat flux, and it was confirmed that the high thermal conductivity of graphene compared to other materials had a dominant effect on the increase in the conduction heat transfer rate. And it was confirmed that the high surface temperature of the graphene coating also increased the heat transfer rate by convection, thereby enhancing the heat dissipation effect.

In this study, we studied the method of using general architectural glass instead of using the existing acrylic material for high luminance flat lighting. The flat panel lighting used the side illumination method to increase the ease of installation and aesthetic satisfaction. In general, glass has an amorphous structure with a lower angle of refraction than acrylic, so it is not suitable for use in flat panel lighting as a light guide, but in this study, the role of light distribution characteristics and diffusion patterns in the case of using such a glass light guide. Quantitative simulations were conducted to confirm new possibilities. In the simulation, the backlight estimation method was used, and about 10,000,000 rays were placed within a unit area in order to obtain a result similar to the real thing. As a result of the simulation, the geometry of the diffusion pattern could be specified, and the value of the geometry could be quantified using the ratio of the diameter and height of the pattern. As a result of the calculation, it was found that the maximum amount of light was generated around 75 degrees by quantitatively calculating the ratio and the outgoing light angle at which the maximum value of the outgoing light occurred between 05 and 1.0. As a result of these studies, it was confirmed that it is possible to use ordinary glass at the same time as a transparent window and light-emitting lighting at night.

The temperature distributions were numerically calculated for the two-dimensional transient conduction heat transfer problem of a square plate. The obtained temperature distributions were converted into colors to create images, and they were provided as learning and test data of CNN. Classification and regression networks were constructed to predict representative wall temperatures through CNN analysis. As results, the classification networks predicted the representative wall temperatures with an accuracy of 99.91% by erroneously predicting only 1 out of 1100 images. The regression networks predicted the representative wall temperatures within errors of C. From this fact, it was confirmed that the deep learning techniques are applicable to the transient conduction heat transfer problems.

In this study, the flat glass and adsorption pad were modeled using SolidWorks Simulation, to understand the deformation characteristics of the vertical flat glass by the adsorption pressure during vertical transport of LCD. The horizontal and vertical displacements and equivalent stresses of the flat glass were investigated by the structural analysis. From the displacement and stress visualization according to the adsorption pressure, the higher the adsorption pressure, the larger the glass surface protruded. The horizontal deformation of flat glass increased with increasing thickness and the vertical deformation increased with decreasing thickness. In addition, the maximum equivalent stress applied to the flat glass increased significantly as the adsorption pressure increased and the thickness decreased. As a result of the structural analysis, the thinner the thickness of the plate glass, the greater the effect on the adsorption pressure. Especially, the effect of the adsorption pressure was clearly observed at the thickness of 0.5mm.

An experimental investigation is performed to study the effect of jet to plate spacing and low Reynolds number on the local heat transfer distribution to normally impinging submerged circular air jet on a smooth and flat surface. A single jet from a straight circular nozzle of length to diameter ratio(l/d) of 83 is tested. Reynolds number based on nozzle exit condition is varied between 500 and 8,000 and jet to plate spacing between 0.5 and 8 nozzle diameter. The local het transfer characteristics are obtained using thermal images from infrared thermal imaging technique. It was observed that at lower Reynolds numbers, the effect of jet to plate distances covered during the study on the stagnation point Nusselt numbers is minimal. At all jet to plate distances, the stagnation point Nusselt numbers decrease monotonically with the maximum occurring at a z/d of 0.5 as opposed to the stagnation point Nusselt numbers at high Reynolds numbers which occur around a z/d of 6.

Marine structures developed for marine industry and resource manifests different fluid characteristics. As such, the changes in the location, shape and size of these structures affect the fluid flow. Specifically, this wake flow caused by the structures result in environmental damage and topographical change. but on the other hand, protects harbor facility and environment. This study was conducted by changing the position of vertical plate in horizontal and vertical direction and experimented the variation of wake flow by PIV. This experiment confirmed the wake flow reduction by the changes of gab in horizontal and vertical direction. Particularly, the experiment showed that changes of gab in horizontal and vertical direction resulted in an increased u-velocity fields in the back of structure for larger horizontal gab.

PURPOSES : The pole electrode method damaged the concrete pavement on inserting the electrode into the pavement surface. This study examined the feasibility of the flat electrode method to observe the concrete pavement instead of the pole electrode method and analyzed the resistivity characteristics of the concrete by performing laboratory tests. METHODS : The resistivity of the concrete specimens manufactured with three different mixing ratios (38.50%, 39.50%, and 40.50%) were measured using the pole and flat electrode methods according to the concrete age (7 and 28 days) and electrode spacing (20 mm, 30 mm, and 40 mm). RESULTS : In both pole and flat electrode methods, the resistivity increased with increasing fine aggregate proportion regardless of the concrete age. The resistivity measured at a concrete age of 28 days was slightly larger than that measured at 7 days. In the case of a concrete age of 7 days, the resistivity measured by the flat electrode method was larger than that measured by the pole electrode method. The difference disappeared at 28 days. CONCLUSIONS: The results suggest that the flat electrode method can replace the pole electrode method because the resistivity measured by both methods was similar. Hence, the development of a technology to apply the flat electrode method to actual concrete pavement is necessary.

폐수는 농도 및 성상에 따라 처리 방법이 다양하지만, 증발식과 역삼투식이 고농도 폐수 농축시 적용되고 있다. 물론, 역삼투식으로 처리한 후에도 배출되는 브라인은 증발식으로 최종 처리하고 있다. 결국, 증발식이 적용되기 전에 최대한 폐수의 부피를 줄이는 것이 에너지 소비 측면에서는 유리하다. 따라서, 본 연구에서는 고농도 폐수 농축에 정삼투 기술을 적용하였다. 특히, 나권형 막모듈의 경우 구조적인 문제로 인해 직렬 연결시 압력강하가 심하게 커지는 단점이 있어, 본 연구에서는 평판형 막모듈을 사용하였다. 실험 결과는 유도용액과 원수의 농도, 두 용액간의 삼투압차, 두 용액의 유량, 막 면적 등이 농축에 영향을 미치는 것으로 분석되었다. 결국, 이런 파라미터들의 최적화가 정삼투 공정에서는 절대적으로 중요하였다.

The heat transfer of Jet impingement is a very effective technique for exchanging high heat fluxs between a heated plate and a fluid. The purpose of current investigation is to carry out the experiment in order to study heat transfer characteristics between a vertical round water jet and a horizontal surface for different flow rates and geometric conditions. The effect of flow rates on heat transfer were investigated. The data obtained in this study are represented in terms of Nusselt number as a function of Reynolds and Peclet numbers. The correlation for the Nusselts number in terms of the Peclet number and  was obtained. The proposed correlation predicts the current data of heat transfer very well.

Stress on plates may increase in the neighborhood the edges or the holes for rivets or bolts. Excessive stress concentration may lead to severe breakage of the plates. Thus, it is important to conduct optimization of arrangement of holes at the design stage. In this paper, accuracy of FEM analysis was examined for such stress concentration . By changing the hole size on a narrow plate, change of the stress concentration factor(K) was investigated. Additionally, the same experiment was conducted about series of multiple holes on plate to investigate interaction between the adjacent holes. Then, the FEM results were compared to the reference predictions respectively. Finally, a method by which simple stress concentrating situations can be optimized, will be suggested. This method was examined by FEM, and showed similar tendency with the expectation. Therefore, this method can be valuable when arranging the holes on a plate.

In this study, a flat-type photocatalytic reactor is applied under solar irradiation for simultaneous treatment of target pollutants: reduction of Cr(VI) to Cr(III) and oxidation of EDCs (BPA, EE2, E2). An immobilized type of photocatalyst was fabricated to have self-grown nanotubes on its surface in order to overcome limitations of powdery photocatalyst. Moreover, Ti mesh form was chosen as substrate and modified to have both larger surface area and photocatalyst content. Ti mesh was anodized at 50V and 25°C for 30min in the mixed electrolytes (NH4F-H2O-C2H6O2) and annealed at 450°C for 2 hours in ambient oxygen to have anatase structure. Surface characterization was done with SEM and XRD methodologies. Fabricated NTT was applied to water treatment, and coexisting Cr(VI) and organics (EDCs) enhanced each other's reactions by scavenging holes and electrons and thus impeding recombination. Also, several experiments were conducted outdoor under direct sunlight and it was observed that both solar-tracking and applying modified photocatalyst were proven to enhance reaction efficiency.

본 연구에서는 높은 이산화탄소 분리성능을 가지는 폴리이미드의 제조를 위해 2,2-bis(3,4-carboxylphenyl) hexafluoropropane과 두종류의 아민인 2,3,5,6-tetramethyl-1,4-phenylenediamine, Poly(ethylene glycol) bis(3-aminopropyl) terminated을 이용하여 합성을 진행하였다. 합성된 고분자를 비용매 상전이법으로 비대칭 분리막을 제조하기 위하여 고분자의 용 해도 지수 추정 값과 비용매 상전이 계수 측정을 통해 용매를 선정하였고, 고분자 용액 점도 측정을 통해 분리막 제조를 위 한 도프용액 중의 고분자의 함량을 결정하여 질산리튬을 첨가제로 사용하여 최종적으로 분리막을 제조하였다. 제조된 평판형 비대칭 분리막은 전자주사현미경(SEM)을 통해 질산리튬과 휘발성 용매 함량에 변화에 따른 모폴로지의 변화를 확인하였으 며, 이의 변화에 따른 기체 투과도 변화를 확인하였다. 분리막 제조를 위한 도프용액 중의 휘발성 용매 함량이 작을수록 선택 도 변화가 없으면서 이산화탄소 투과도가 증가하는 것을 확인하였다.

본 논문에서는 굽힘하중이 가해지는 스마트 복합재 적층판의 자유단에서 발생하는 박리응력을 압전 작동기를 이용해서 감소시키는 방법을 응력함수를 이용해 해석하는 방법을 제안하였다. 전기-기계 연성에 의해 나타나는 지배방정식은 최소 보족일의 원리를 이용해 구하였다. 응력상태는 일반적인 고유치 해석과정을 통해 구하였다. 스마트 복합재 적층판의 자유단 박리응력은 압전 작동기를 이용해 감소시킬 수 있었다. cross-ply 복합재 적층판의 박리응력 감소가 angle-ply 복합재 적층판 보다 크게 나타났다.