We present a simple method of fabricating a hierarchically nanostructured CuO–Cu current collector by using laser ablation and metal mold imprinting to maximize the surface area. The laser ablation of the Cu current collector created the CuO nanostructure on the Cu-collector surface. The microstructure was transferred by subsequent imprinting of the microstructure metal mold on the Cu collector. Then, the laser-ablation nanostructure was formed. Consequently, a hierarchical structure is generated. The laser-ablated hierarchical CuO–Cu current collector exhibited an improved capacity while maintaining a cyclability that is similar to those of conventional graphite batteries.

Electric power production continues to increase as the industry advances, and the demand for high-capacity batteries for efficient operation of the electric power produced is higher than ever before. Si has been attracting a great deal of attention recently as an anode electrode material because of its high theoretical capacity. However, it suffers from significant capacity-loss, resulting from the volume-expansion of Si during charge and discharge cycles. Inspired by the multiscale structures commonly found in nature, we attempt to solve this problem by patterning the surface of the Cu current-collector. To this end, we develop a direct, one-step method using laser patterning to manufacture a multiscale structure on the surface of the current-collector. The inherent exfoliation characteristic of the Cu current-collector allows the spontaneous formation of the multiscale structure while being irradiated with a laser. A micro/nano structure, with a different surface area, is fabricated by varying the laser output at three levels, and the batteries prepared with the fabricated Cu current-collector are tested to evaluate their charge-discharge characteristics and electrochemical impedance. The results show that the multiscale structure reduces mechanical stress. The initial capacity of the Cu current-collector is proportional to the laser output, and the initial capacity of the coin cell prepared with the Cu current-collector, fabricated at the highest laser output, is 396.7% higher than that of the coin cell prepared with a bare Cu current-collector. The impedance is inversely proportional to the laser output. The charge transfer resistance of the coin cell prepared with the Cu current-collector and irradiated with the highest laser output is 190.2% lower than that of the coin cell prepared with the bare Cu current-collector.

Traffic sign identification is one of the key components of the Driver Assistant Systems (DAS). It can provide important information for safety driving. In this paper, we propose a method for traffic sign detection and identification. First, potential traffic signs are segmented by color threshold, and a polygon approximation algorithm is used to detect appropriate polygons. The potential signs are compared with the template signs in the database using SURF feature matching method. In the identification step, we apply the SURF algorithm for a CPU only system and a CPU with GPGPU system. Experiment results show that our method works robustly and efficiently for the selected data.

본 연구는 방탄복 방탄시험에서 탄약 제조사 간 성능 차이와 탄착점 위치에 따른 방탄복의 방탄성능 차이 여부를 확인하기 위해 수행되었다. 탄약의 제조사 간 성능 차이 검증을 위해 저장 중인 육군 다목적 방탄복 Ⅰ형 4벌에 대해 P-BFS 시험을 실시하고 후면변형 결과를 t-검정으로 분석하였다. 또한 탄착점 위치에 따른 방탄성능 차이를 검증하기 위해 ○○년과 △△년 제조된 방탄복의 수락시험 결과 데이터를 사용하여 ANOVA 분석을 수행하였다. 본 연구의 결과는 다음과 같다. 먼저, .44 Magnum 탄의 제조사 간 성능 차이 비교를 위해 후면변형치에 대한 t-검정을 실시한 결과, 탄 제조사에 따른 방탄성능의 차이는 존재하지 않는 것으로 확인되었다. 다음으로 탄착점 위치에 따른 방탄성능 비교를 위해 ○○년도 방탄복과 △△년도 방탄복에 .44 Magnum 탄약과 .357 SIG 탄약을 사용하여 시험한 후면변형의 ANOVA 분석 결과, 2가지 탄종 모두에서 탄착점 별 후면변형의 차이는 발생하지 않았다.