• 중국학논총
• /
• no.65
• /
• pp.167-192
• /
• 2020

城市化, 一方面具有特殊性, 如同中國; 另一坊面具有普遍性, 如同地球上的大部分社會已經都經歷過或者正在經歷著 。所謂的全球規模的城市化就是從圍繞城市化的中國之特殊性及全球規模的普遍性中, 或者是從中國的城市化所呈現出來的具體性中抽象出來的, 這說明城市化, 中國, 中國的城市化之間具有密不可分的關系。由此, 本文試圖運用嶄新的方法論-"城市文化研究"來探討這種相互關系和漢字的溝通(不)可能性又是具有何等關系, 如何預測由此產生的前景等問題。爲此, 本文第一步基於"行星城市化(planetary urbanization: urbanisation planétaire)"的理論性, 實踐性背景闡明了全球規模的城市化和中國的關系。第二步在貫穿整個農村社會和城市社會的"城市革命"框架下對中國的城市化進行了細緻分析。第三步首先論證在國家不斷建造城市空間的背景下由於國家及政黨深入幹預中國的現實空間, 虛擬空間, 及與此具有緊密關系的精神空間, 因此不可能建立現實空間和虛擬空間之間辯證關系, 然後進而診斷漢字的溝通(不)可能性, 最後通過分析"城市革命"的另一個側面來提出其替代方案。

• Tribology and Lubricants
• /
• v.38 no.1
• /
• pp.22-26
• /
• 2022

A 1.7-ton grade small excavator is a construction equipment that can perform various functions in limited spaces where heavy equipment cannot enter easily. Owing to the recent acceleration of urbanization, it has been used increasingly in drainage and gas pipes, as well as for road repair works in urban areas. The power train of a traveling reducer for a 1.7-ton grade small excavator utilizes a complex planetary gear system. Complex planetary gears are vital to the power train of a traveling reducer as it mitigates the fatigue strength problem. In the present study, the specifications of a complex planetary gear train are calculated; furthermore, the gear bending and compressive stresses of the complex planetary gears are analyzed to achieve an optimal design of the latter in terms of cost and reliability. In this study, the actual gear bending and compressive stresses of a planetary gear system are analyzed using a self-developed gear design program based on the Lewes and Hertz equation. Subsequently, the calculated specifications of the complex planetary gears are verified by evaluating the results with the data of allowable bending and compressive stress based on curves of stress vs. number of cycles of the gears.

• Journal of Climate Change Research
• /
• v.7 no.3
• /
• pp.357-371
• /
• 2016

Buildings in the city acts as a cause of distorted wind direction, wind speed, causing the stagnation of the air flow. In the recent trend of climate change can not but consider the temperature rise of the urbanization. This study was aimed to analyze the thermal comfort of planetary boundary layer in different artificial constructions areas which has a direct impact on urban climate, and estimating the warming phenomena. Envi-met model was used to consider the urban structure associated with urban growth in order to precisely determine the impact of the building on the city weather condition. The analyzed values of thermal comfort index were temperature, wind speed, horizontal and vertical turbulent diffusivity. In particular, analysis of the PPD(Predicted Percentage of Dissatisfied) represents the human thermal comfort. In this study, by adjusting the arrangement and proportion of the top floor building in the urban it was found that the inflow of the fresh air and cooling can be derived low PPD. Vertical heat flux amount of the city caused by climate change was a factor to form a high potential temperature in the city and the accumulation of cold air does not appear near the surface. Based on this, to make the city effectively respond to climate change may require a long-term restructuring of urban spatial structure and density management.

• Atmosphere
• /
• v.26 no.1
• /
• pp.111-126
• /
• 2016

In the numerical weather model, surface properties can be defined by various parameters such as terrain height, landuse, surface albedo, soil moisture, surface emissivity, roughness length and so on. And these parameters need to be improved in the Seoul metropolitan area that established high-rise and complex buildings by urbanization at a recent time. The surface roughness length map is developed from digital elevation model (DEM) and it is implemented to the high-resolution numerical weather (WISE-WRF) model. Simulated results from WISE-WRF model are analyzed the relationship between meteorological variables to changes in the surface roughness length. Friction speed and wind speed are improved with various surface roughness in urban, these variables affected to temperature and relative humidity and hence the surface roughness length will affect to the precipitation and Planetary Boundary Layer (PBL) height. When surface variables by the WISE-WRF model are validated with Automatic Weather System (AWS) observations, NEW experiment is able to simulate more accurate than ORG experiment in temperature and wind speed. Especially, wind speed is overestimated over $2.5m\;s^{-1}$ on some AWS stations in Seoul and surrounding area but it improved with positive correlation and Root Mean Square Error (RMSE) below $2.5m\;s^{-1}$ in whole area. There are close relationship between surface roughness length and wind speed, and the change of surface variables lead to the change of location and duration of precipitation. As a result, the accuracy of WISE-WRF model is improved with the new surface roughness length retrieved from DEM, and its surface roughness length is important role in the high-resolution WISE-WRF model. By the way, the result in this study need various validation from retrieved the surface roughness length to numerical weather model simulations with observation data.