16 resultados para Sostenibilità, tetti verdi, urban green technology, LID, SUDS, LCA.
em Chinese Academy of Sciences Institutional Repositories Grid Portal
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城市绿地是城市景观的重要组成部分,起着调节城市生态环境、美化城市景观、提供休闲游憩场所的重要作用,在城市发展中扮演着关键角色。沈阳市近年来将城市绿地建设作为城市建设的重要方面,取得了显著成效。因此,本文利用2006年Quick Bird高分辨率卫星影像对沈阳市三环内的城市绿地景观格局进行了研究,具体结论如下: (1) 沈阳三环内绿地斑块18261个,绿地面积 173.71km2,斑块数目主要以中型斑块为主(62.25%);在面积上以大型斑块为主(85.59%);绿地总体呈现斑块分布不均衡。 (2) 居住绿地、单位附属绿地与道路绿地破碎化程度高,分布分散,斑块形状复杂。城市绿地廊道连通性较高,道路绿地平均分维数最大。 (3) 公园绿地亚类中,综合型公园与带状公园面积较大,破碎化程度低;社区公园与街头绿地面积较小,破碎化程度高,分布分散。 (4) 绿地景观整体上,绿地斑块密度较大,破碎化程度高,景观多样性指数为1.6,斑块类型丰富,均匀度指数为0.73,蔓延度指数为0.83,存在着少数类型控制整个景观的现象。 (5) 绿地系统梯度分析表明:类型水平上,不同的绿地类型沿景观格局梯度表现出明显的空间特征;景观水平上,不同景观指数沿样带梯度也表现出差异性,表明城市化导致景观的破碎化程度增大,景观异质性增高。城乡边缘区绿地类型最为丰富,多样性指数较高,其格局有利于绿地生态环境维护功能的发挥。
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本文利用中高分辨率遥感影像研究2006年沈阳市三环内城市绿地的空间格局及2001-2006年间的变化,以期对5年的高强度绿化建设进行评价。利用QuickBird高分辨率遥感影像,结合基于知识分类方法提取的植被覆盖信息和目视解译方法提取的土地利用信息,分析了2006年附属绿地的空间分布格局和公园绿地可达性。利用2001、2006年两景Landsat TM影像,基于线性混合分解方法提取的植被盖度信息,分析了5年间的绿化建设强度及其空间分布。 本文得到以下结论: 1) 工业用地和公共设施用地的绿化率均较高,分别是28.9%和32.3%。研究区域多层老式居住用地和道路的绿化率只有近20%。新居住用地中高层片块居住用地的平均斑块面积较小,主要是由小块的街区角落开发而成,绿化率只有10.3%;其余的新居住用地的绿化率均高于多层老式居住用地。居住用地高度类型相同的情况下,花园式居住用地比片块式居住用地拥有更高的绿化率。 2) 附属绿地绿化率随距市中心距离的递增梯度反映了城市内外绿化状况的两极分化现象,在几种主要的城市用地类型之间存在差异:公共设施(4.16%∙km-1)>多层老式居住用地(3.85%∙km-1)>新居住用地(3.05%∙km-1)>道路(2.36%∙km-1)。新居住用地弱于多层老式居住用地,表明随着旧城改造的持续进行,居住用地的内外两极分化现象可以得到缓解。公共设施用地的内外两极分化现象较严重,城市化进程中慎重对待高绿化率的公共设施用地如高校等迫于地价压力的外迁行为。 3) 公园绿地可达性分析的结果表明,只有29.25%的居住用地分布在距最近公园绿地5分钟的步行范围内,43.31%的居住用地在5-15分钟的步行范围内,建议持续增加公园绿地建设,尤其是在工商业密集区。研究区域尚未出现居住用地绿化环境的马太效应(高公园绿地可达性+高附属绿地绿化率)。 4) 2001-2006年,道路、居住用地、公共设施用地、公共绿地及广场的植被盖度均有不同程度的增加(5%-9%),证实了5年间绿化建设力度之大;工业用地的植被盖度几乎没有变化,原因估计是工业用地空间属于非公共空间,不属于公共绿化建设区域。5年间植被增量空间分布均匀,没有针对低绿化覆盖率地区加强绿化建设力度,部分缓解了绿化率的城市内外两极分化现象。
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针对当前城市水资源匮乏和人居环境问题,根据城市生态学和城市水文学的基本原理,以集雨消尘为主线对新研究领域——城市绿色环境系统进行了理论研究、技术设计和应用示范.最小生态风险选择原则、生态边缘效应的两向性和城市绿色环境集雨利用的操作单元(终端)划分的研究成功地为集雨利用建立了理论基础;以垂向设计为特点,设计了可普遍应用的一般集雨利用模式和在不同具体条件下的量化模式;根据气候因素及集雨利用目的,对中国城市绿色环境系统集雨利用区域进行了区划,划分4个区;同时得出,绿地在城市绿色环境系统自净作用中的核心地位.分析认为,“设计”的应用将会产生巨大的生态效益和经济效益.指出现行城市绿色环境系统格局是一种落后、低质低效的运行模式.集雨设计模式应用的示例城市选择了包头市市政区,应用的集雨生态系统终端选择了包头市医学院大院;给出了应用的方法步骤:①确定集雨区;②根据集雨利用区气候和其他特点和建设要求,进行终端划分;③根据各水文参数做集雨利用模式规划设计;④将设计纳入城市建设规划.
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A colorless transparent, blue green emission material was fabricated by sintering porous glass impregnated with copper ions. The emission spectral profile obtained from Cu+ -doped high silica glass (HSG) by 267-mn monochromatic light excitation matches that obtained by pumping with an 800-nm femtosecond laser, indicating that the emissions in both cases come from an identical origin. The upconversion emission excited by 800-nm femtosecond laser is considered to be a three-photon excitation process. A tentative scheme of upconverted emission from Cu+ -doped HSG was also proposed. The glass materials presented herein are expected to find application in lamps, high density optical storage, and three-dimensional color displays.
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The edible blue-green alga, Nostoc sphaeroides Kutzing, is able to form microcolonies and spherical macrocolonies. It has been used as a potent herbal medicine and dietary supplement for centuries because of its nutraceutical and pharmacological benefits. However, limited information is available on the development of the spherical macrocolonies and the environmental factors that affect their structure. This report described the morphogenesis of N. sphaeroides from single trichomes to macrocolonies. During the process, most structural features of macrocolonies of various sizes were dense maculas, rings, the compact core and the formation of liquid core; and the. laments within the macrocolonies showed different lengths and arrays depending on the sizes of macrocolonies. Meanwhile temperature and light intensity also strongly affected the internal structure of macrocolonies. As microcolonies further increased in size to form 30 mm macrocolonies, the colonies differentiated into distinct outer, middle and inner layers. The. laments of the outer layer showed higher maximum photosynthetic rates, higher light saturation point, and higher photosynthetic effciency than those of the inner layer; whereas the. laments of the inner layer had a higher content of chlorophyll a and phycobiliproteins than those of the outer layer. The results obtained in this study were important for the mass cultivation of N. sphaeroides as a nutraceutical product. (c) 2008 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.
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Strongly reducing organic substances (SROS) and iron oxides exist widely in soils and sediments and have been implicated in many soil and sediment processes. In the present work, the sorptive interaction between goethite and SROS derived from anaerobic decomposition of green manures was investigated by differential pulse voltammetry (DPV). Both green manures, Astragaltus sinicus (Astragalus) and Vicia varia (Vicia) were chosen to be anaerobically decomposed by the mixed microorganisms isolated from paddy soils for 30 d to prepare different SROS. Goethite used in experiments was synthesized in laboratory. The anaerobic incubation solutions from green manures at different incubation time were arranged to react with goethite, in which SROS concentration and Fe(II) species were analyzed. The anaerobic decomposition of Astragalus generally produced SROS more in amount but weaker in reducibility than that of Vicia in the same incubation time. The available SROS from Astragalus that could interact with goethite was 0.69 +/- 0.04, 0.84 +/- 0.04 and 1.09 +/- 0.03 cmol kg(-1) as incubated for 10, 15 and 30 d, respectively, for Vicia, it was 0.12 +/- 0.03, 0.46 +/- 0.02 and 0.70 +/- 0.02 cmol kg(-1). One of the fates of SROS as they interacted with goethite was oxidation. The amounts of oxidizable SROS from Astragalus decreased over increasing incubation time from 0.51 +/- 0.05 cmol kg(-1) at day 10 to 0.39 +/- 0.04 cmol kg(-1) at day 30, but for Vicia, it increased with the highest reaching to 0.58 +/- 0.04 cmol kg(-1) at day 30. Another fate of these substances was sorption by goethite. The SROS from Astragalus were sorbed more readily than those from Vicia, and closely depended upon the incubation time, whereas for those from Vicia, the corresponding values were remarkably less and apparently unchangeable with incubation time. The extent of goethite dissolution induced by the anaerobic solution from Vicia was greater than that from Astragalus, showing its higher reactivity. (c) 2008 Published by Elsevier Ltd.
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Sediment core samples were collected in the largest urban Lake Donghu (Stations I and II) in China, and the activities of Pb-210, Ra-226 and Cs-137 were measured by gamma-ray spectrometry. The sedimentation rates, calculated by 210Pb constant rate of supply (CRS) model, ranged from 0.11 to 0.65 (average 0.39) cm(.)y(-1) at Station I, and from 0.21 to 0.78 (average 0.46) cm(.)y(-1) at Station II. Sedimentation rate calculated by Cs-137 as a time marker was 0.55 cm(.)y(-1) at Station II. Based on the average sedimentation rate, we obtained 769 and 147 t(.)y(-1) for nitrogen and phosphorus retentions in Lake Donghu sediments, respectively.
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Nostoc flagelliforme, which is distributed in arid or semiarid steppes of the west and west-northern parts of China, has been used by the Chinese as a food delicacy and for its herbal values for hundreds of years. However, the resource is being over-exploited and is diminishing, while the market demands are increasing with the economic growth. This review deals mainly with the Chinese studies on the ecology, physiology, reproduction, morphology and culture of this species in an attempt to promote research and development of its cultivation technology.
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Studies on mixed mass cultivation of Anabaena spp. on a large scale (5170 m2) were conducted continuously for 3 years. Under the continental monsoon climate in northern subtropics (30-degrees-N, 115-degrees-E), 7-11 g dry weight m-2 day-1 of microalgal biomass on average was harvested in simple plastic greenhouses in the effective growth days during the warmer seasons. The maximum productivity was 22 g m-2 day-1 in the middle of summer. Observations on the productive properties of strains of Anabaena spp. indicated that they were different from and could compensate for each other in their productivities and adaptations to the seasonal changes. With different lining materials (PVC sheets, concrete, sand and soil) in the culture ponds, no significant variation of productivity was found, but bubbling with biogas in the middle of the day and the application of some growth regulating substances (2,4-D, NaHSO3 and extracts of oyster mushroom spawn) was able to improve the production. The cost of microalgal biomass in this way was around 0.75-1.0 US dollar(s) per kilogram.
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Blue-green GaN-based vertical cavity surface emitting lasers (VCSELs) were fabricated with two dielectric Ta2O5/SiO2 distributed Bragg reflectors. Lasing action was observed at a wavelength of 498.8 nm at room temperature under optical pumping. Threshold energy density and emission linewidth were 189 mJ/cm(2) and 0.15 nm, respectively. The result demonstrates that blue-green VCSELs can be realised using III-nitride semiconductors.
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Back Light Unit (BLU) and Color Filter are the two key components for the perfect color display of Liquid Crystal Display (LCD) device. LCD can not light actively itself, so a form of illumination, Back Light Unit is needed for its display. The color filter which consists of RGB primary colors, is used to generate three basic colors for LCD display. Traditional CCFL back light source has several disadvantages, while LED back light technology makes LCD obtain quite higher display quality than the CCFL back light. LCD device based on LED back light owns promoted efficiency of display. Moreover it can generate color gamut above 100% of the NTSC specification. Especially, we put forward an idea of Color Filter-Less technology that we design a film which is patterned of red and green emitting phosphors, then make it be excited by a blue light LED panel we fabricate, for its special emitting mechanism, this film can emit RGB basic color, therefore replace the color filter of LCD device. This frame typically benefits for lighting uniformity and provide pretty high light utilization ratio. Also simplifies back light structure thus cut down the expenses.
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Tb/Yb共掺的石英光纤的上转换绿光发光研究,研究了最佳浓度配比和发光机理。
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An electrical-to-green efficiency of more than 10% was demonstrated by intracavity-frequency-doubling a Q-switched diode-side-pumped Nd:YAG laser with a type II lithium triborate (LBO) crystal in a straight plano-concave cavity. An average power of 69.2 W at 532 nm was generated when electrical input power was 666 W. The corresponding electrical-to-green conversion efficiency is 10.4%. To the best of our knowledge, this is the highest electrical-to-green efficiency of second harmonic generation laser systems with side-pumped laser modules, ever reported. At about 66 W of green output power, the power fluctuation over 4 hours was better than +/-0.86%.
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Based on the RS and GIS methods, Siping city is selected as a study case with four remote sensing images in 25 years. Indices of urban morphology such as fractal dimension and compactness are employed to research the characteristics of urban expansion. Through digital processing and interpreting of the images, the process and characteristics of urban expansion are analysed using urban area change, fractal dimension and compactness. The results showed that there are three terms in this period. It expended fastest in the period of 1979~1991, and in the period of 1992~2001, the emphases on urban redevelopment made it expended slower. And this is in agreement with the Siping Statistical Yearbook. This indicates that the united of metrics of urban morphology and statistical data can be used to satisfactorily describe the process and characteristics of urban expansion. © 2008 IEEE.
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Multilayer films were fabricated by layer-by-layer electrostatic deposition techniques between poly(diallyIdimethylammonium chloride) (PDDA) and calf thymus DNA (CT DNA) on glassy carbon and quartz substrates. Electrochemical impedance spectroscopy (EIS), Fourier transform infrared (FTIR) spectroscopy and UV-vis spectroscopy demonstrated the uniform assembly of PDDA/DNA multilayer films, and X-ray photoelectron spectroscopy confirmed the elemental composition of the films. Moreover, the interaction of DNA in PDDA/DNA films with methyl green was investigated by UV-vis spectroscopy and circular dichroism (CD). (C) 2001 Elsevier Science B.V. All rights reserved.