In this study, Ni-Y2O3 powder was prepared by alloying recomposition oxidation sintering (AROS), solution combustion synthesis (SCS), and conventional mechanical alloying (MA). The microstructure and mechanical properties of the alloys were investigated by spark plasma sintering (SPS). Among the Ni-Y2O3 powders synthesized by the three methods, the AROS powder had approximately 5 nm of Y2O3 crystals uniformly distributed within the Ni particles, whereas the SCS powder contained a mixture of Ni and Y2O3 nanoparticles, and the MA powder formed small Y2O3 crystals on the surface of large Ni particles by milling the mixture of Ni and Y2O3. The average grain size of Y2O3 in the sintered alloys was approximately 15 nm, with the AROS sinter having the smallest, followed by the SCS sinter at 18 nm, and the MA sinter at 22 nm. The yield strength (YS) of the SCS- and MA-sintered alloys were 1511 and 1688 MPa, respectively, which are lower than the YS value of 1697 MPa for the AROS-sintered alloys. The AROS alloy exhibited improved strength compared to the alloys fabricated by SCS and conventional MA methods, primarily because of the increased strengthening from the finer Y2O3 particles and Ni grains.
In the flux used in the batch galvanizing process, the effect of the component ratio of NH₄Cl to ZnCl₂ on the microstructure, coating adhesion, and corrosion resistance of Zn-Mg-Al ternary alloy-coated steel is evaluated. Many defects such as cracks and bare spots are formed inside the Zn-Mg-Al coating layer during treatment with the flux composition generally used for Zn coating. Deterioration of the coating property is due to the formation of AlClx mixture generated by the reaction of Al element and chloride in the flux. The coatability of the Zn-Mg-Al alloy coating is improved by increasing the content of ZnCl2 in the flux to reduce the amount of chlorine reacting with Al while maintaining the flux effect and the coating adhesion is improved as the component ratio of NH4Cl to ZnCl2 decreases. Zn-Mg-Al alloy-coated steel products treated with the optimized flux composition of NH₄Cl•3ZnCl₂ show superior corrosion resistance compared to Zn-coated steel products, even with a coating weight of 60 %.
본 논문에서는 저가의 MEMS 관성 센서와 지자기 센서를 이용하여 자세 정보를 제공받는 자세측정장치(ARHS)를 구현하였다. 저가형 IMU센서와 MCU를 이용하여 운동 자세각을 계산하는 DCM 알고리즘을 설계하고, 3축짐벌에 장착하여 연산결과의 정확도를 측정하였다. DCM 알고리즘을 이용 연산된 자세각의 정확도는 roll 및 pitch에 대하여 약 1.1%로 나타났으며, yaw각의 경우는 3.7%로 나타났다. Yaw 각의 경우에는 스텝핑 모터를 구동하는 실험환경에 따른 교란의 영향으로 그 오차가 상대적으로 크게 나타난 것으로 평가되었다. 짐벌 실험장치를 이용한 센서의 검증에서 더욱 정밀한 실험을 위해서는 주변 환경 요인에 대한 제어가 요구될 것으로 보이며, 실험장치의 스테핑 모터 구동 시 발생하는 진동 및 자기장의 영향과 실험 장치의 금속성 구조물의 영향으로 생각되는 센서 데이터의 오차 및 불안정 상태를 차단할 수 있는 장치의 보완이 필요할 것으로 보인다. 그리고 지자기 센서의 경우 좁은 범위의 측정에 추가하여 넓은 범위의 측정도 보완되어야 할 것으로 생각된다.
본 논문에서는 저가, 저전력 및 소형의 IMU를 구성하기 위한 MEMS 관성 센서를 이용하여 자세 정보를 제공받는 ARHES에 위의 센서를 사용하기 위해 자이로 센서 및 가속도센서의 데이터 출력 특성을 검증하여 오차 및 정확도를 분석하였다. 센서 실험을 위하여 진자 실험 장치를 제작하였고, 진자 운동에 대한 센서 데이터를 수집하였다. 이론적인 수식을 유추하여 센서 데이터의 정확성 분석을 위한 기준 값으로 설정하였다. 센서값과 이론값을 비교하면 각속도에서 4.32~5.72%, 가속도에서 x-, z-축 방향에 대하여 각각 3.53~6.74% 및 3.91~4.16%의 오차율을 나타냈다. 진자실험 장치를 이용한 센서 검증에서 무인헬리콥터에 사용될 센서로서 적합한 것으로 평가되었으며 이는 짐벌장치 등을 이용한 자세추정 알고리즘을 구성하는데 기초가 되었다. 또한, 더욱 정밀한 실험을 위해서는 온도 등 주변 환경 요인에 대한 보정이 요구된다.
As the balcony expansion of residential building was legalized, the expansion generation is tend to increased continuously of existing residential building or condominium complex. But balcony is the service area. So, it is worried about defect occurrence of extension construction because thermal insulation effect is insufficient to balcony installed an aluminum sash. Therefore, it is desired the method to minimize the damage of performance improvement of the windows which has an influence directly on the performance defect. See-through a-si is effective to reduce the cooling loads and sunlight, to produce the electricity by installing a-si at the wall and windows of residential building. This paper has predicted producing electricity and have analyzed heating/cooling load based on balcony expansion and building-integrated PV installation in residential building.
With the development of artificial lighting technology, human can breakout the limitation of the natural light and make it possible to create a brilliant civilization. However, the wide used outdoor artificial lighting caused severe environmental problem called "Light Pollution" due to human's less cognition of using light and excessive light. Obtrusive light at nighttime can do harm to the human health and observation activity. In this paper, the upward light control process of general lighting fixtures was suggested for reducing the adverse effects such as sky glow in the central city and light trespass in the residential areas.
Environmental lighting zone-setting has suggested regulatory standards according to the influence of artificial illumination on natural environment and human life. Then, it is necessary to check out the viability of environmental lighting zone division as it is limited to use-zone division. This study aims to suggest some problems, which occur when environmental lighting zone is set by use-zone only, by comparing and analyzing the artificial illumination luminance. In addition, this study aims to suggest basis for the environmental lighting zone-setting and eventually, more effective environmental lighting zone division.
This study fouces on the electricity generation of B1PV system in the super-tall buildings. To improve the efficiency of the B1PV system, solar irradiance and air temperature should be taken into consideration. This study does research on, one of two main parameters, the solar irracliance in the super high-rise buildings. According to the measurement of solar irracliance, it increased with altitude. It is, particularly, more obviously in the super-tall buildings than others. Subsequently, to make an accurate B1PV elecrticity generation prediction,it is necessary to anaiyze the solar irracliance distribution on the super-taII building's facade which is a prerequisite for optimal B1PV system design.
Environmental lighting zone-setting has suggested regulatory standards according to the influence of artificial illumination on natural environment and human life. Then, it is necessary to check out the viability of environmental lighting zone division as it is limited to use-zone division. This study aims to suggest some problems, which occur when environmental lighting zone is set by use-zone only, by comparing and analyzing the artificial illumination luminance. In addition, this study aims to suggest basis for the environmental lighting zone-setting and eventually, more effective environmental lighting zone division.
The paper mainly discusses on the method how to save energy so as to follow the "Low Carbon and Green Growth" by the govemment and the Building Energy Efficiency Rating System. For the purpose of interior comfort as well as effective operation and management of buildings, this paper does basic research on development of elementary technology for saving the energy used in building. In this paper, the interior lighting control zone is selected to make a lighting control algorithm which takes the reduction of building energy into consideration for saving building energy when the building envelopes are replaced by the BIPV system.
Light pollution is a side effect of industrial civilization. It obscures the stars in the night sky for city dwellers, interferes with astronomical observatories, and, like any other form of pollution, disrupts ecosystems and has adverse health effects. It is most severe in highly industrialized, densely populated areas of North Arnerica, Europe, and Japan. Nowadays, light pollution has become a global problem and the public concerns on disputes of light pollution have been on the rise. Unfortunately, we haven't had any comprehensive and systematic regulation of lighting pollution yet. Therefore, we need to make our own regulation of lighting pollution to deal with it. The purpose of this study is making a research on the standards and countermeasures of light pollution at home and abroad before establishing our own regulation based on which we can resolve and reduce the light pollution.
This study was carried out to evaluate the Life Cycle Cost(LCC) of four types of BIPV(Building Integrated Photovoltaic) systems -Glass plus Granite, Crystalline BIPV, Crystalline BIPV + Glass plus Granite and See through Amorphous BIPV -which were vertically installed to generate the same capacity(2kW) and the same area. Initial investment costs, cost savings and maintenance costs had been predicted during the period of analysing the LCC of four types of BIPV(Building Integrated Photovoltaic) systems installed for the purpose of evaluating the LCC. In case of cost savings, it had been analyzed by measuring the amount of electric power generated, reduction in lighting load and heat & cooling loads through simulation. From this analysis, it was predicted that the See-through amorphous BIPV offering cost saving advantages demonstrated the economical efficiency similar to the Glass plus Granite when it is backed by more than 20 years of durability.
경로 탐색은 인공지능의 매우 중요한 요소 중의 하나이며, 여러 분야에서 두루 쓰이는 과정이다. 경로 탐색은 매우 많은 연산이 필요하기 때문에 성능에 매우 중대한 영향을 미친다. 이를 해결하기 위해서 연산량을 줄이는 방식의 연구가 많이 진행되었고, 대표적으로 A* 알고리즘이 있으나 불필요한 연산이 있어 효율성이 떨어진다. 본 논문에서는 A* 알고리즘 중 연산 비용이 높은 노드 탐색 수 등 연산량을 줄이기 위해서 가중치 기반의 선수행 A* 알고리즘을 새롭게 제안한다. 제안한 알고리즘의 효율성을 측정하기 위해 시뮬레이션을 구현하였으며, 실험 결과 가중치를 이용하는 방법이 일반적인 방법보다 약 1~2배 높은 효율을 보였다.
충돌 처리는 게임의 물리 법칙을 구현하기 위하여 매우 중요한 요소 중의 하나이며, 게임을 생동감 있게 하기 위한 과정이다. 충돌 처리는 매우 많은 연산이 필요하기 때문에 게임 성능에 중대한 영향을 미친다. 이를 해결하기 위해서 연산량을 줄이는 방식의 연구가 많이 진행되었고, 대표적으로 SAP 알고리즘이 많이 사용되고 있으나 반복되는 연산이 있어 효율성이 떨어진다. 본 논문에서는 충돌 처리의 연산량을 줄이고 SAP 알고리즘의 문제점을 해결하기 위하여, 거리기반 SAP 알고리즘을 새롭게 제안한다. 본 논문에서 제안한 알고리즘으로 만든 시뮬레이션 프로그램을 이용하여 FPS를 측정하는 실험을 진행한 결과, 제안한 알고리즘을 사용하는 경우가 사용하지 않는 경우에 비해서 FPS가 약 2~33배 높았기 때문에 충돌 처리의 효율이 향상되었다고 판단할 수 있었다.