The first purpose was to identify the plantar pressure distributions (peak pressure, pressure integral time, and contact area) during level walking, and stair ascent and descent in asymptomatic flexible flatfoot (AFF). The second purpose was to investigate whether peak pressure data during level walking could be used to predict peak pressure during stair walking by identifying correlations between the peak pressures of level walking and stair walking. Twenty young adult subjects (8 males and 12 females, age 21.0±1.7 years) with AFF were recruited. A distance greater than 10 ㎜ in a navicular drop test was defined as flexible flatfoot. Each subject performed at least 10 steps during level walking, and stair ascent and descent. The plantar pressure distribution was measured in nine foot regions using a pressure measurement system. A two-way repeated analysis of variance was conducted to examine the differences in the three dependent variables with two within-subject factors (activity type and foot region). Linear regression analysis was conducted to predict peak pressure during stair walking using the peak pressure in the metatarsal regions during level walking. Significant interaction effects were observed between activity type and foot region for peak pressure (F=9.508, p<.001), pressure time integral (F=5.912, p=.003), and contact area (F=15.510, p<.001). The regression equations predicting peak pressure during stair walking accounted for variance in the range of 25.7% and 65.8%. The findings indicate that plantar pressures in AFF were influenced by both activity type and foot region. Furthermore the findings suggest that peak pressure data during level walking could be used to predict the peak pressure data during stair walking. These data collected for AFF can be useful for evaluating gait patterns and for predicting pressure data of flexible flatfoot subjects who have difficulty performing activities such as stair walking. Further studies should investigate plantar pressure distribution during various functional activities in symptomatic flexible flatfoot, and consider other predictors for regression analysis.

We report a highly sensitive NO2 gas sensor based on multi-layer graphene (MLG) films synthesized by a chemical vapor deposition method on a microheater-embedded flexible substrate. The MLG could detect low-concentration NO2 even at sub-ppm (<200 ppb) levels. It also exhibited a high resistance change of ~6% when it was exposed to 1 ppm NO2 gas at room temperature for 1 min. The exceptionally high sensitivity could be attributed to the large number of NO2 molecule adsorption sites on the MLG due to its a large surface area and various defect-sites, and to the high mobility of carriers transferred between the MLG films and the adsorbed gas molecules. Although desorption of the NO2 molecules was slow, it could be enhanced by an additional annealing process using an embedded Au microheater. The outstanding mechanical flexibility of the graphene film ensures the stable sensing response of the device under extreme bending stress. Our large-scale and easily reproducible MLG films can provide a proof-of-concept for future flexible NO2 gas sensor devices.

PURPOSES : The impact performance of flexible barrier system such as structural response, vehicular motion and occupant safety vary depending on the impact point. Thus, to properly evaluate the performance of a flexible barrier system, impact should be made to a point which will lead to the worst possible results. This point is called the Critical Impact Point (CIP). This paper presents the way to determine the CIP for a SB2 class flexible barrier system which is consisted of Thrie-Beam rail and circular hollow tube post of 2m span. METHODS: Barrier VII simulations were made for impact points; Case 1 at a post, Case 2 at 1/3 span downstream from a post, Case 3 at middle of the span, Case 4 at 2/3 span downstream from a post. For the structural performance (deflections), impact simulation of 8000kg-65km/h-15degree was used, and for vehicle motion and occupant safety, simulation of 1300kg-80km/h-20degree impact was made and analysed. RESULTS: Case 1 gave the largest dynamic deflection of 75.72cm and also gave the largest snag value of 44.3cm. Occupant safety and exit angle of the vehicle after the impact were not sensitive to the impact point and were all below the allowable limit. CONCLUSIONS : For the SB2 class flexible barrier system's CIP can be regarded as a post which is sufficiently away from the end of Length of Need in order to avoid the end-effect of the barrier system. It can be more economic in the long run because the normal concrete pavement material is likely to cost more due to higher probability of maintenance and repair and higher social cost due to traffic accident, etc.

Flexible Driving System(FDS)는 제조업(주로 자동차 생산공장 및 전자제품 생산공장, 식품공장 등) 생산공장에서 사용되는 무인 자동화 운반설비를 말한다. 지금으로부터 200년전 James Ford가 개발했던 공장자동화의 역사는 산업혁명을 거치면서 발전을 거듭하였으며 최근에는 작업자의 안전 및 돌발적 사고로 인한 생산성 급감이 생산공장에서는 중요한 이슈로 떠오르고 있으며, 이를 보완하기 위한 기존 시스템의 운반설비 시스템에 더욱 스마트한 기능을 더한 자동화설비에 대한 필요성이 증대되었다. 이를 위해 먼저 현재 생산중인 제어부 전차반의 크기를 기존 대비 30 % 정도 compact하게 재설계하여 소형화함으로써 종래의 기어방식의 컨베이어 시스템의 대용으로 사용되며, 향후 전문화 될 경우 Electrical Moving System(EMS)가 널리 사용되게 될 전망이다.

Flexible polyurethane/clay porous nanocomposite foams were synthesized using natural and organically modified montmorillonite clays such as bentonite, closite 10A and closite 30B. The content of nanoclays was varied from 1 to 5 wt% of polyol. Dispersion of clay in Polyurethane(PU) matrix was investigated by X-ray diffraction(Cu-Kα rays of wavelength 1.54Å) using an X-ray diffractometer. Also, we determined that the thermal resistance of PU foam increased with added clay, compared to that of pure PU foam. The cell size and the fraction of open cells of the precursor foam were controlled by the addition of clay to the polyurethane foam. Modified clays were found to be more efficient cell openers than the unmodified clay. In addition, the tensile strength and elongation of the polyurethane/clay porous nanocomposites were examined. Increasing clay content increased the mechanical properties of the composites, such as tensile strength, and elongation at break. However, increasing the content over 5 wt% deteriorated the properties of the composites. We found that the nanofillers(bentonite, closite 10A and closite 30B) improved the thermal stability of the nanocomposite foam. The nanocomposite foam containing 3 wt% of closite 30B exhibited the best tensile strength and thermal stability.

As the Sewer Pipe is transformed by the expansion of life cycle as a result of the technology development, flexible pipe is developed by the transformed environmental conditions. To change pipe design, three phases(compaction ration - inner deflection ratio - ring stiffness) should be considered in design conditions. The input data of pipe design were provided by compaction-inner deflection ratio-ring stiffness. M oreover, The guidelines of sewerage pipes should be considered by flexible pipes design criteria.

This study is carried out to develop the new process for the fabrication of ultra-fine electrodes on the flexible substrates using superhydrophobic effect. A facile method was developed to form the ultra-fine trenches on the flexible substrates treated by plasma etching and to print the fine metal electrodes using conductive nano-ink. Various plasma etching conditions were investigated for the hydrophobic surface treatment of flexible polyimide (PI) films. The micro-trench on the hydrophobic PI film fabricated under optimized conditions was obtained by mechanical scratching, which gave the hydrophilic property only to the trench area. Finally, the patterning by selective deposition of ink materials was performed using the conductive silver nano-ink. The interface between the conductive nanoparticles and the flexible substrates were characterized by scanning electron microscope. The increase of the sintering temperature and metal concentration of ink caused the reduction of electrical resistance. The sintering temperature lower than resulted in good interfacial bonding between Ag electrode and PI film substrate.

Manganese dioxide (MnO2) is one of the most important cathode materials used in both aqueous and non-aqueous batteries. The MnO2 polymorph that is used for lithium primary batteries is synthesized either by electrolytic (EMD-MnO2) or chemical methods (CMD-MnO2). Commonly, electrolytic manganese dioxide (EMD) is used as a cathode mixture material for dry-cell batteries, such as a alkaline batteries, zinc-carbon batteries, rechargeable alkaline batteries, etc. The characteristics of lithium/manganese-dioxide primary cells fabricated with EMD-MnO2 powders as cathode were compared as a function of the parameters of a manufacturing process. The flexible primary cells were prepared with EMD-MnO2, active carbon, and poly vinylidene fluoride (PVDF) binder (10 wt.%) coated on an Al foil substrate. A cathode sheet with micro-porous showed a higher discharge capacity than a cathode sheet compacted by a press process. As the amount of EMD-MnO2 increased, the electrical conductivity decreased and the electrical capacity increased. The cell subjected to heat-treatment at 200˚C for 1 hr showed a high discharge capacity. The flexible primary cell made using the optimum conditions showed a capacity and an average voltage of 220 mAh/g and 2.8 V, respectively, at 437.5μA.

본 연구의 목적은 유연 광섬유의 스마트 의류용 로고 디자인을 개발하기 위한 디자인 지침을 도출하는 것이다. 로고 디자인을 위한 지침 도출의 기준은, 첫째 광섬유 전면에 걸쳐 적절한 밝기 정도를 나타내는지의 여부, 둘째 광섬유 전면에 걸쳐 비교적 균일한 밝기 특성을 나타내는가 등이었다. 이를 위하여, 실험 1에서는 광섬유사의 각도 변화와 길이에 따른 유연 광섬유의 밝기 특성을 분석하였으며, 실험 2에서는 실제 의류용 로고 디자인을 위한 지침을 도출하기 위해, 알파벳 대문자의 주요 형태소 등의 유연 광섬유 밝기 특성을 분석하였다. 두 개의 실험 결과를 토대로 하여, 유연 광섬유로 구성된 의류용 로고 디자인을 위한 지침과 제한점을 도출하였다.

In this study, an oxygen plasma treatment was used as a low temperature debinding method to form a conductive copper feature on a flexible substrate using a direct printing process. To demonstrate this concept, conductive copper patterns were formed on polyimide films using a copper nanoparticle-based paste with polymeric binders and dispersing agents and a screen printing method. Thermal and oxygen plasma treatments were utilized to remove the polymeric vehicle before a sintering of copper nanoparticles. The effect of the debinding methods on the phase, microstructure and electrical conductivity of the screen-printed patterns was systematically investigated by FE-SEM, TGA, XRD and four-point probe analysis. The patterns formed using oxygen plasma debinding showed the well-developed microstructure and the superior electrical conductivity compared with those of using thermal debinding.

광섬유 직물 기반 스마트 의류가 국, 내외로 개발되고 있는 실정이며, 기존의 일반적인 광섬유는 직물화가 어렵고 내구성, 내수성이 결여되어 세탁 및 유지 관리의 한계로 인해 에칭된 광섬유사의 표면에 합성수지를 코팅 처리하는 '내수성 광섬유사 가공 기술'이 최근 개발 되었다. 본 연구에서는 제직 후 측광가공 된 유연 광섬유 직물을 대상으로 광섬유사 길이에 따른 특성과 광원 색채에 따른 발광 특성을 분석, 평가하여 디지털 컬러 의류의 적용 적합성을 파악하고자 한다. 이를 위하여 광섬유사 길이에 따른 총 4가지 유연 광섬유 직물시료를 제직하여, 이를 대상으로 광원 색채에 따른 유연 광섬유 직물의 휘도, 물리적 가시도, 지각적 가시도를 측정함으로써 발광특성을 분석하였다. 그 결과, 10cm인 유연 광섬유 직물과 녹색 광원을 사용한 경우가 최대가시거리 100m로 디지털 컬러 의류 즉, 안전보호 기능의 산악복 적용에 가장 적합한 발광효과를 보이는 것으로 나타났다. 그러므로 본 연구의 결과는 앞으로 유연 광섬유 직물 적용 의류 개발과 관련된 후속 연구의 자료로서 활용될 수 있을 것으로 기대된다.

이 연구에서 GRP 관의 하중-처짐 거동을 조사, 보고하였다. 지중매성 GRP관은 높은 내화학성, 높은 부식저항성, 경 량성, 관표면의 매끄러움, 지반-관의 상호작용 고려에 따른 경제성 등의 탁원한 역학적, 물리적 특성들로 인해 건설 현장에서 광범위하게 사용되고 있다. 지중에 매설되는 연성관을 설계하기 위해서는 ASTM D 2412 (2010)에 따라야 한다. ASTM D 2412 (2010)에 따라 설계할 경우, 관의 원강성 (PS)을 편평시험에 따라 먼저 결정해야 하는데, 이 시 험이 귀찮고 노동력을 필요로 한다. 이러한 문제를 해결하기 위해 UTM에 설치된 형태의 GRP관의 하중-처짐 거동 을 유한요소법에 따라 모사하였으며, 유한요소법에 의한 모사에는 재료의 탄성계수와 단면의 기하학적 치수 등 기 초적인 자료를 사용하였다. 이와 같은 연구로부터, 관재료가 관의 단면내에서 비교적 일정하지 않음에도 불구하고 수직방향의 관변형이 3%와 5%가 발생할 경우, 편평시험과 수치해석적 연구 결과가 15%이내의 차이로 하중의 예측 이 가능함을 알 수 있었다.

최근 IT 융합 기술이 글로벌 시장의 핵심 화두로 떠오르면서, 스마트 의류 분야에서도 '의류+서비스 제공(service provider)' 기능을 갖는 PSS형 제품 디자인에 대한 수요가 크게 증가하고 있다. 본 연구에서는PSS형 제품 디자인의 일환으로서 안전보호 기능의 산악복 용도에 적합한 발광특성을 지닌 유연 광섬유 기반 직물 디스플레이의 제직구성을 모색하고, 이를 적용한 산악복 모형 디자인을 제시하였다. 이를 위하여 제직 구성, 즉 직물조직과 광섬유 밀도가 다른 총 15개 광섬유 직물 디스플레이 시료를 제직하여, 이를 대상으로 각각의 휘도를 측정함으로써 발광특성을 분석하였다. 그 결과, '주자직 2:1', '주자직 3:1' 및 '능직 2:1', '능직 3:1'인 경우가 안전보호 기능을 위한 산악복으로서 적용이 가장 적합한 발광효과를 보이는 것으로 나타났다. 발광특성에 관한 분석 결과 및 최근 스포츠 패션 트렌드를 기초로 하여, 유연 광섬유 직물 디스플레이 적용 산악복 모형 디자인을 전개하였다.

Recently, all-electrified houses have constructed and some tasks are being carried out to monitor energy consumption patterns. The energy monitoring includes various elements such as temperature, pressure, water flow, CO2, and electricity. In this monitoring, electricity consumption is one of the essential factors because the performance and energy saving levels are described by this physical quantity. This quantity depends on materials, structure, operation of the house, which operation means consumer's life style and usage patterns of home appliances furthermore. Firstly, this paper shows a control simulation method which were developed a few years ago. And some different methods are proposed considering flexible experimental condition.

Si Nanowire (NW) field effect transistors (FETs) were fabricated on hard Si and flexible polyimide (PI) substrates, and their electrical characteristics were compared. Si NWs used as channels were synthesized by electroless etching method at low temperature, and these NWs were refined using a centrifugation method to get the NWs to have an optimal diameter and length for FETs. The gate insulator was poly(4-vinylphenol) (PVP), prepared using a spin-coating method on the PI substrate. Gold was used as electrodes whose gap was 8 μm. These gold electrodes were deposited using a thermal evaporator. Current-voltage (I-V) characteristics of the device were measured using a semiconductor analyzer, HP-4145B. The electrical properties of the device were characterized through hole mobility, Ion/Ioff ratio and threshold voltage. The results showed that the electrical properties of the TFTs on PVP were similar to those of TFTs on SiO2. The bending durability of SiNWs TFTs on PI substrate was also studied with increasing bending times. The results showed that the electrical properties were maintained until the sample was folded about 500 times. But, after more than 1000 bending tests, drain current showed a rapid decrease due to the defects caused by the roughness of the surface of the Si NWs and mismatches of the Si NWs with electrodes.

A system approach for studying the engine dynamic characteristics requires a cranktrain flexible body dynamic model including crankshaft, connecting rod and piston. By using a multi-body dynamics code, LMS Virtual Lab, rigid body dynamic model and flexible multi-body dynamic model were established. From these models, the dynamic loads acting on the crankshaft were calculated. Rigid model for V12 engine cranktrain with components connected by kinematical constraints was transformed into a flexible model by replacing rigid crankshaft and connecting rods with flexible ones. And to secure the credibility of flexible body model, three kinds of flexible models were tried, i.e. a model with a fully flexible crankshaft, model with a partially flexible crankshaft(1/6 of the whole length), and a partial detailed flexible model(with finer meshes). The results from each model were compared, and a partial detailed model with finer meshes was found to give reasonable stress values within relatively short period of computing time.

최근 개발된 테이블탑 시스템들은 컴퓨터 게임의 장점을 살리면서 동시에 전통적인 보드 게임 환경을 재현할 수 있는 장점이 있다. 그리고 이러한 시스템들은 사람들이 많이 모이는 장소에서 기존의 테이블 축구나 핀볼 기계 같은 아날로그 게임 시스템들을 대체하게 될 것이다. 하지만 이러한 테이블탑 시스템들은 그 확장성이 제한되기 때문에 여러 사람이 동시에 게임을 즐기는 것이 어렵다. 따라서 더 많은 사용자들이 게임을 함께 즐기고 상호작용에 참여할 수 있는 물리적인 공간과 고해상도 디스플레이 환경을 지원하기 위해서는 테이블탑 시스템의 규모를 유연하게 확장할 수 있어야 한다. 본 연구에서는 여러 개의 단일 타일드 테이블탑 시스템을 서로 동적으로 연결하여 하나의 초대형 통합 시스템을 구성함으로써 보다 확장된 게임 개발을 지원하는 프레임워크를 개발하였다. 본문에서는 기존 테이블탑 환경의 게임 플랫폼 기술들을 살펴 본 후에, 본 프레임워크의 설계 및 개발 내용에 대하여 상세히 설명한다. 그리고 유효성을 측정하기 위한 성능 평가에 대해서 기술한다.

Changes in surface morphology and roughness of dc sputtered ZnO:Al/Ag back reflectors by varying the deposition temperature and their influence on the performance of flexible silicon thin film solar cells were systematically investigated. By increasing the deposition temperature from 25˚C to 500˚C, the grain size of Ag thin films increased from 100 nm to 1000 nm and the grain size distribution became irregular, which resulted in an increment of surface roughness from 6.6 nm to 46.6 nm. Even after the 100 nm thick ZnO:Al film deposition, the surface morphology and roughness of the ZnO:Al/Ag double structured back reflectors were the same as those of the Ag layers, meaning that the ZnO:Al films were deposited conformally on the Ag films without unnecessary changes in the surfacefeatures. The diffused reflectance of the back reflectors improved significantly with the increasing grain size and surface roughness of the Ag films, and in particular, an enhanced diffused reflectance in the long wavelength over 800 nm was observed in the Ag back reflectors deposited at 500˚C, which had an irregular grain size distribution of 200-1000 nm and large surface roughness. The improved light scattering properties on the rough ZnO:Al/Ag back reflector surfaces led to an increase of light trapping in the solar cells, and this resulted in a noticeable improvement in the Jsc values from 9.94 mA/cm2 for the flat Ag back reflector at 25˚C to 13.36 mA/cm2 for the rough one at 500˚C. A conversion efficiency of 7.60% (Voc = 0.93, Jsc = 13.36 mA/cm2, FF = 61%) was achieved in the flexible silicon thin film solar cells at this moment.

The vibration control of a flexible rotor supported on cavitated short squeeze film dampers is investigated. According to Pan's theory, the shape of cavitation in fluid film bearings depends on the level of oil supply pressure, as a result, both the direct and the cross coupled damping coefficients of a cavitated short squeeze film damper are varied widely. In this paper, controling the level of oil supply pressure by fuzzy theory, a significant reduction in journal eccentricity ratio, rotor amplitude and force transmissiblilty of a flexible rotor system is achieved.