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51.
《Carbon》2013
A novel method for the assembly of thin, uniform transparent and conductive films of single-walled carbon nanotubes (SWCNTs) on glass substrates is described. This process involves the initial transfer of a temporary suspension of SWCNTs in room temperature ionic liquid to the surface of water and the subsequent transfer of the SWCNT film onto a glass substrate. The average sheet resistance of the films was determined by four point probe measurements to be 1.52 and 4.13 kΩ/sq, with an average optical transparency of 50% and 63%, respectively. 相似文献
52.
Diane M. Styers Arthur H. Chappelka Luke J. Marzen Greg L. Somers 《Landscape and urban planning》2010,94(3-4):158-165
As moderate-sized cities become more urbanized, ecosystems are altered by land-use change. Key ecological services, such as clean air and water, drought and flood protection, soil generation and preservation, and detoxification of wastes are disrupted, risking the health and welfare of society. An understanding of ecosystem responses to urbanization is necessary to evaluate and balance short-term needs with long-term sustainability goals. Our main objective was to develop a land management and planning tool using a land-cover classification to select landscape indicators of ecosystem health near Columbus, GA. Spearman's Rho correlations were calculated to compare landscape and field-based indicators. Results suggest there are significant inverse correlations between ‘percent forest land-cover’ and ‘population, housing, and road densities’; ‘tree species richness’ and ‘forest patch density’; ‘percent urban land-cover’ and ‘lichen species richness’; ‘lichen incidence’ and ‘forest perimeter-area fractal dimension’. Overall, there were 152 significant urban/biological correlations obtained from this assessment (Rho ≥ |0.50| and p ≤ 0.10). Such a tool could prove useful to land managers and environmental planners by providing a quick and simple method to assess broad areas of land in a single analysis. 相似文献
53.
The land potential for producing biomass for bioenergy purposes has been highly debated in recent years. The present paper analyses the possibilities and consequences for land use and agricultural production of biofuel production in Denmark based on domestic wheat and rape under specific scenario conditions for the period 2010–2030. The potential is assessed for a situation where policy targets for renewable energy carriers in the transport sector is reached using biofuels, and where second generation ethanol increasingly substitutes first generation ethanol.Three scenarios are developed and evaluated: a baseline, an alternative scenario allowing continuous growth in the now dominant livestock branch and a biofuel scenario assuming that efforts to achieve self-sufficiency in biofuel displaces part of the domestic production of fodder.Results show that the biofuel demand could be met in 2020; but only if current rape oil production is used to satisfy local bio-diesel demand. It would also imply that the Danish bio-diesel export currently supplying a minor part of the German fuel market would seize. In 2030, however, only about 60 percent of the biofuel demand would be covered by self-sufficiency. If biofuels were to displace animal production to make up for this, a reduction of the pig production between 10 and 20 percent would result. Efficiency increases across production branches would allow the animal production to continue un-affected if about half of the rape oil produced for other purposes is utilized. 相似文献
54.
《Landscape and urban planning》2007,79(4):322-333
Rapid land use change has taken place in many mega cities of China such as Beijing over the past two decades. In this paper, land use change dynamics were investigated by the combined use of satellite remote sensing, geographic information systems (GIS). The results indicated that there had been a notable and uneven urban growth and a major loss of cropland loss between 1986 and 2001. Most of the urban growth and loss of agriculture land occurred in inner and outer suburbs. Land use change was projected for the next 20 years using Markov chains and regression analyses. The further integration of remote sensing and GIS technologies with Markov model and regression model was found to be useful for describing, analyzing and predicting the process of land use change. 相似文献
55.
M. Aulinas P. Tolchinsky C. Turon M. Poch U. Cortés 《Engineering Applications of Artificial Intelligence》2012,25(2):317-325
The daily operation of wastewater treatment plants (WWTPs) in unitary sewer systems of industrialized areas is of special concern. Severe problems can occur due to the characteristics of incoming flow. In order to avoid decision that leads to hazardous situations, guidelines and regulations exist. However, there are still no golden standards by which to a priori decide whether a WWTP can cope with critical discharges. Strict adherence to regulations may not always be convenient, since special circumstances may motivate operators to accept discharges that are above established thresholds or to reject discharges that comply with guidelines. Nonetheless, such decisions must be well justified. This paper proposes an argumentation-based model by which to formulate a flexible decision-making process. An example of the model application describes how experts deliberate the safety of a discharge and adapt each decision to the particular characteristics of the industrial discharge and the WWTP. 相似文献
56.
Satellite images allow characterizing and monitoring urban slums. Yet the urban landscape as a complex geographic system is composed of hierarchical patterns and discrete objects in a spatial and temporal continuum with different scales and anisotropy which can only be estimated from image snapshots. Understanding the spatial heterogeneity of slums in terms of scale and anisotropy from discrete image pixels is nontrivial and has not been explicitly addressed by image-based studies detecting slums, where scale and direction in characterizing slum features are commonly done by trial and error. This study addresses this gap by analyzing the impact of scales and anisotropy detected in the scale space and frequency domain for the calculation of texture indices that ultimately govern the detection of slums. Employing case studies of three cities with a large portion of slum population and for which we have very high resolution satellite imagery, we identify the characteristic scales of slum and formal built-up areas. Results show that the characteristic scales correspond with the optimal grain size to obtain image texture features for detecting slums, while the directional spectral energy at the pixel level identifies characteristic directions. Thus texture indices calculated at the characteristic scale and along the characteristic directions of slum patterns improve the efficiency in feature extraction and classification of slums, where optimizing the scale has a higher impact on the detection of slums than choosing the optimal directions. This study provides a framework for scientifically selecting optimal scales and directions for slum mapping studies. The framework is recommended to be tested for more general applications in land surface characterization and classification especially by using high order texture indices. 相似文献
57.
Yuanzheng Li Xiaoqiang Gong Zhen Guo Kaipeng Xu Hongxuan Zhou 《International journal of remote sensing》2016,37(16):3611-3635
The extraction of water distribution is extremely useful in research and planning activities, including those associated with water resources, environments, disasters, local climates, and other factors. Remote-sensing images with moderate resolution have been the main data source due to the vast distribution of water and the high cost, access difficulty, and massive size of high-resolution images. Although some water indices and methods for water extraction have been proposed, there is still a lack of these resources to easily, accurately, efficiently, and automatically extract water. This paper focused on some improvements that mainly used the most traditional but also the newest Operational Land Imager (OLI) images in Landsat 8. This study first analysed the variation features of previous water indices. Secondly, taking the city of Beijing and its surrounding area as the experimental site, a spectral curve analysis was performed and a new water index was proposed. This index was compared to three typical indices. Thirdly, a new approach was proposed to accurately and easily extract water. It included four major steps: background partitioning, thresholding and preliminary segmentation, noise removal by patch size, and local region growth. Next, the stricter and more effective stratified random sampling method was used to test the accuracy. Then, we tested the generality of the proposed water index and extraction method using nine typical test sites from around the world and tried to simplify the workflow. Finally, this paper discusses threshold optimization issues, such as automatic selection and reduction of the number of thresholds. The results show that the normalized water index (NDWI), modified normalized water index (MNDWI), and normalized difference built-up index (NDBI) may fail in some situations due to the complex spectrum of the impervious surface class. Some shadow pixels were impossible to remove using only spectral analysis because both the digital number (DN) trends and values were similar to those of water. The proposed water index was easy and simple, but it corresponded better to water bodies. Additionally, it was more accurate and universal and showed greater potential for extracting water. This method relatively accurately and completely extracted various water bodies from plain city, plain country, and natural mountainous regions in many typical climate zones, eliminating interference caused by dark impervious surfaces, plants, sand, suspended sediments, snow, ice, bedrock, reservoir drawdown areas, shadows from mountains and buildings, mixed pixels, etc. The mean kappa coefficients were 0.988, 0.982, and 0.984 in plain city, plain country, and natural mountainous regions, respectively. This paper suggests that thresholds can be automatically determined by comparing the accuracy changes of different thresholds according to preselected sample and test points. Furthermore, the combined use of the maximum class square error method (also known as the Ostu algorithm) and the adaptive thresholding method exhibits great potential for automatic determination of thresholds in regions without many noises with higher water index values. In addition, water bodies could also be accurately extracted by setting these thresholds to fixed values based on the results at more test sites. 相似文献
58.
绿豆、红小豆和黑豆种皮18 种元素分析 总被引:1,自引:0,他引:1
为全面了解绿豆皮、红小豆皮和黑豆皮的18 种元素含量,充分开发利用豆皮资源,提高豆类加工产品
的附加值,用元素分析(elemental analyzer,EA)仪和电感耦合等离子体发射光谱(inductively coupled plasmaatomic
emission spectrometer,ICP-AES)仪测定了3 种豆皮的N、C、S、Ca、Mg、K、P、Na、B、Ba、Co、
Cr、Cu、Fe、Mn、Ni、Zn和Sr元素含量。结果表明,EA仪测定豆皮中N、C和S方法检出限为32~96 μg/g,回收
率为97%~115%,相对标准偏差为0.20%~2.63%(n=5);ICP-AES测定豆皮中Ca、Mg、K、P、Na、B、Ba、
Co、Cr、Cu、Fe、Mn、Ni、Zn和Sr元素方法检出限为0.02~152 μg/g,回收率为84%~118%,相对标准偏差为
0.44%~4.46%(n=5)。黄豆标准物N、Mg、P、B、Ba、Co、Cr、Mn、Ni、Zn和Sr元素测定值在推荐范围内,
S、Ca、K、Na、Cu和Fe元素测定值接近推荐值。分析方法快速、简便,达到了应用的要求。 相似文献
59.
A. Urkiaga L. de las Fuentes B. Bis E. Chiru B. Balasz F. Hernández 《Desalination》2008,218(1-3):81-91
The full implementation of the Urban Waste Water Treatment Directive (91/271/EEC) in Europe will contribute to obtain treated wastewaters of quite high quality that could be reused for certain applications or improved by polishing steps for uses with higher quality requirements. Even though reclaimed water reuse is currently implemented in many European countries, mainly for irrigation, its potential has not yet been exploited in many areas. In fact, a decisive factor to achieve a higher percentage of water reuse is the establishment of effective incentives, which in many instances will be of either an economic or a regulatory nature. The limiting factor for water reuse can in many circumstances be the quality of the water available linked to the treatment processes (technology) and potential hazards for secondary users. In any case, its economic viability needs a careful cost-benefit analysis for the various parties involved to be carried out. However, some water reuse implementation projects have failed because some other key factors, such as social awareness or associated ecological effects, were not accounted for. Thus, the consideration of regulatory, economic, technological, social and environmental factors seems essential to successfully accomplish a reclaimed water reuse project. Feasibility studies can contribute to obtain the success in the implementation of a water reuse project. Within AQUAREC a feasibility study methodology for the performance of water reuse projects has been developed, considering the above mentioned key factors and providing the tools for their analysis. These guidelines aim at assisting the different stakeholders (administration, engineering companies, water management bodies, etc.) involved in the implementation of a water reuse programme in a specific area. AQUAREC Handbook on Feasibility Studies for Water Reuse Systems, publicly available, deals with all information needs necessary to successfully face a water reuse project. Background information data collection support, technology options evaluation or environmental impact assessment guidelines are offered in this publication. Furthermore, the assessment methodologies and indicators for social, economic and environmental factors are also provided. Last but not least, cost effectiveness analysis methodologies and technology validation are also addressed. 相似文献
60.
《Journal of power sources》1997,68(1):24-29
There is a considerable lack of detailed information on the structure of lithiated phases of popular-consensus positive electrode materials for lithium/polymer and lithium-ion/polymer batteries. Having illustrated this phenomenon for the specific cases of LiMn2O4 and V6O13, some suggestions are made to present the problem in a more general context. The need for single-crystal diffraction studies is indicated. 相似文献