Highly Oriented Pyrolytic Graphite (HOPG) was half covered using aluminum foil and exposed to irradiation with 70 keV C+ ions at room temperature (~ 25 ℃). The surface layer (height = 178.3 ± 4.7 nm) of the irradiated area was destroyed, many nano-sized dendritic protrusions were observed and smooth inner layer was exposed. The peak area ratio (ID/IG) in Raman spectra increased after ion irradiation, indicating that a change in atomic structure and transformation from the sp2 to sp3 phase. The mechanical properties were explored using atomic force microscopy in peakforce mode, which revealed that the Young’s modulus of the exposed inner layer was similar to unirradiated area, while the Young’s modulus of the dendritic protrusions was higher. There findings provided further understanding of the HOPG at nanoscale, which is of value for practical implementation in related fields.
21세기 초부터 중국의 해외관광산업이 많이 활발해졌고, 운남성도 이러한 배경 하에 주변국가와 관광산업분야에서 협력의 폭과 깊이를 넓힐 수 있었다. 중국-미얀마 경제회랑은 중국이 설립 된 두 번째 무역회랑이며 이는 란창-메콩 지역발전에 중요한 역할을 하고 있다. 학술계는 운남 및 미얀마 양측의 관광산업을 중심으로 한 협력이 더욱더 활성화 될 거라고 전망하고 있다. 본 논문은 중국-미얀마 경제 회랑 건설을 기반으로 중국 Dehong지역과 미얀마 간의 관광산업협력 현황 및 협력 메커니즘, 인프라 구축, 국경 간 관광 상품 개발 및 관광 서비스 등을 분석하였고, 또한 Dehong과 미얀마 간 관광 협력에 적합한 친환경적인 협력모델을 탐색하였다.
A new deformation micromechanism operating in the carbon cathode for aluminum electrolysis termed a ripplocation has been proposed in this paper. The creep deformation of semi-graphitic cathode was measured using a modified Rapoport equipment at 965 °C with cryolite ratio = 4.0. The characteristic of the defect was obtained by analyzing TEM photograph of the carbon cathode with different testing times. The results indicated that basal dislocations, bulk ripplocations, kink bands and delamination cracks appeared in succession in the first two stages of the creep deformation. Ripplocations in the carbon cathode make a layer of carbon atoms to glide relative to each other without damaging the in-plane bonds. Ripplocations could also attract each other and result in kink boundaries. The creep strain of the carbon cathode could be accommodated by kink band and delamination cracks during aluminum electrolysis. A more comprehensive understanding of their micromechanics behaviors is very important and could deeply influence our current knowledge of the deformation mechanism of the carbon cathode for aluminum electrolysis.
When air with high humidity is stagnant in a huge hot-rolling building, condensation occasionally occurs on the surface of hot-rolling steel coils, degrading quality of the products. To resolve this problem, we tried to utilize the natural ventilation effectively by modifying the location and size of opening vents based on quantitative visualization of ventilation flow inside the factory building. The 1/850 scale-down building model was embedded inside an atmospheric boundary layer simulated in a wind tunnel. The effects of wind direction and location of opening vents on the ventilation flow inside the factory building were investigated experimentally. Instantaneous velocity fields inside the building model were measured using a 2-frame PIV system. Among four dominant wind directions for the building tested, the condensation phenomena occurred monthly for the case of south wind. The addition of a vent on the southern wall of the factory building improved the natural ventilation effectively.