Energy Consumption and Space Density in Urban Area

AbstractEnergy consumption is a technical issue or a spatial structure issue? Aim of this paper is to study the impact of population density and energy consuming density to space together on energy consuming with urban districts of Beijing. The author of this paper puts two kinds of factors including economic and technological ones, and urban space context factors with energy consuming together into a model. LMDI method will be employed to do the analysis. It is concluded that non-economic and non-technological factors were also significant to reduce energy consumption. Even population density did not contribute to reduction of energy consuming, when it was combined with energy consuming density to space together, the contribution was efficient. It indicates that compacted urban space with low-carbon city is the most efficient way to reduce energy consuming in urban areas.© 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of RIUD

Relations between global city connectivity of the primary city and the size national economy

Some scholars emphasize the global cities network and suggest the declining of the national power. On the contrary, many studies insist on the role of the national economy on global cities. However, there is no specific model to show this relation and no evidence to conform which factor at national level impact this connectivity. The aim of this paper is to set up a specific model to illustrate the relationship between the national economic size and global cities connectivity, and to find the factor at national level impacting on world city connectivity. Bootstrap regression is adopted to set up the model for the relation. The results reveal that the national economic size has significant effectiveness on the global city connectivity with logarithmic function. This finding gives an explicit approach to clarify the idea of 'glocal' states with the combination of global city connectivity and national urban system

Commuting tools and residential location of suburbanization: evidence from Beijing

Since the 1990s, the population of Beijing has decentralized. This paper studies the relationship between residents’ commuting tools and their residential location during suburbanization by applying field survey data, statistical methods, and Geographic Information System techniques. The results show that public transportation is the most common choice for commuting. Residents commute the shortest distance do so by walking/bicycling and residents commute the longest distance do so by taking bus/subway. The likelihood of using bus/subway increases as the distance becomes longer; the likelihood of commuting by car/taxi has a very weak correlation with commuting distance. The results imply a public transportation-oriented suburbanization model in Beijing. By further mapping the subway lines and the geographic distribution of newly built houses from 2008 to 2012, it is discovered that public transit especially the subway plays a significant role in residential relocation in Beijing. This could explain the city sprawl in suburbanization in China

Atomic configuration of hydrogenated and clean tantalum(111) surfaces : bond relaxation, energy entrapment and electron polarization

By studying the tantalum (Ta)(111) surface with X-ray photoemission spectroscopy and density functional theory, we determined binding energy values for the clean Ta(111) (+3.068 eV) and hydrogenated Ta(111) (+3.421 eV) surfaces with an isolated atom level of 18.977 eV. Using the bond–band barrier and zone-selective electron spectroscopy correlation, we investigated the mechanism of hydrogenation adsorption on the Ta(111) surface. We found the local densities of states of the first layer of Ta atoms in the reconstructed structure, which formed on the adsorbent hydrogen of the surface chemical bond contracts and dipole polarization. Moreover, we showed that on the Ta(111) surface, the hydrogen-induced surface core level shifts are dominated by quantum entrapment and are proportional to the calculated hybridized orbitals of the valence band. The latter is therefore correlated to the local surface chemical reactivity and is useful for other adsorbate systems on transition metals

Mapping wetland changes in China between 1978 and 2008

Four wetland maps for all China have been produced, based on Landsat and CBERS-02B remote sensing data between 1978 and 2008 (1978, 1990, 2000 and 2008). These maps were mainly developed by manual interpretation and validated by substantial field investigation in 2009. Based on these maps, we analyzed the 2008 wetland distribution in China and discussed wetland changes and their drivers over the past 30 years. (i) There were about 324097 km(2) of wetlands in 2008, for which inland marshes or swamps were the most common wetland type (35%), with lakes (26%) second. Most of the wetlands were in Heilongjiang, Inner Mongolia, Qinghai and Tibet, occupying about 55% of the national wetland area. (ii) From 1978 to 2008, China's wetland area continually and significantly decreased, by about 33% based on changes in the wetland map. This was in sharp contrast to the increase in artificial wetlands, which increased by about 122%. Inland marshes accounted for the main loss of total wetlands from 1978 to 2000. From 2000 through 2008, riverine and lacustrine wetlands constituted the main wetland loss. Fortunately however, the rate of wetland loss decreased from 5523 to 831 km(2)/a. (iii) The change ratio of lost natural wetlands (including inland and coastal wetlands) to non-wetlands has decreased slightly over the past 30 years. From 1978 to 1990, nearly all natural wetlands (98%) lost were transformed into non-wetlands. However, the ratio declined to 86% from 1990 to 2000, and to 77% from 2000 to 2008. (iv) All Chinese provinces were divided into three groups according to patterns of wetland changes, which could relate to the driving forces of such changes. Tibet was completely different from other provinces, as it was one representative example in which there was a net wetland increase, because of global warming and decreased human activity since 1990. Increased economic development caused considerable wetland loss in most eastern provinces, and artificial wetlands increased.National High-tech R&D Program of China [2009AA122003