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基于GPS精确授时技术的快速双向“绿波带”控制
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作者 方虎生 张金林 +2 位作者 芮挺 廖明 王钊 《华东公路》 2006年第1期74-76,共3页
介绍了一种利用GPS精确授时技术在城市干线实现快速、双向无电缆协调控制的方法。利用干线无线同步软件算法和MAXBAND算法,系统可以实现高精度、高稳定、快速的双向"绿波带"控制。
关键词 干线协调控制 GPS精确授时技术 “绿带”控制
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旺加里·马塔伊 和平的绿色使者
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作者 康红辉 《绿色中国(公众版)》 2004年第11M期41-43,共3页
一生最大的惊喜 今年10月8日,肯尼亚环境和自然资源部副部长--现年64岁的旺加里·马塔伊惊喜地得知,由于对环保与人权所作的贡献,她已被授予2004年度诺贝尔和平奖.
关键词 旺加里·马塔伊 诺贝尔和平奖 肯尼亚 环境保护 “绿运动” 可持续发展 植树造林
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Phylogenetic evaluation of the taxonomic status of Papilio maackii and P.syfanius(Lepidoptera:Papilionidae) 被引量:2
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作者 诸立新 吴孝兵 《Zoological Research》 CAS CSCD 北大核心 2011年第3期248-254,共7页
The taxonomic status of Papilio maackii and P.syfanius has long been disputed.We conducted a molecular phylogenetic study to evaluate the taxonomic status of P.maackii and P.syfanius.A total of twenty-four P.maackii i... The taxonomic status of Papilio maackii and P.syfanius has long been disputed.We conducted a molecular phylogenetic study to evaluate the taxonomic status of P.maackii and P.syfanius.A total of twenty-four P.maackii individuals from six localities and sixteen P.syfanius individuals from two localities were analyzed.We sequenced the partial region of the CO-I gene(about 579 bp) and partial CO-II gene sequence(about 655bp) of the two species.The Kimura-2-Parameter distances among P.maackii and P.syfanius ranged from 0 to 0.6%.Fifteen haplotypes were obtained based on the combined data set.The results strongly supported that all P.maackii individuals and all P.syfanius individuals formed a large clade,and could not be divided into separated clades.This research indicated that the two species have only very recently undergone speciation. 展开更多
关键词 Papilio maackii Papilio syfanius CO-I CO-II PHYLOGENY TAXONOMY
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Forest structure,productivity and soil properties in a subtropical ever-green broad-leaved forest in Okinawa,Japan 被引量:1
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作者 徐小牛 王勤 柴田英昭 《Journal of Forestry Research》 SCIE CAS CSCD 2008年第4期271-276,共6页
Structure, species composition, and soil properties of a subtropical evergreen broad-leaved forest in Okinawa, Japan, were examined by establishment of plots at thirty sites. The forest was characterized by a relative... Structure, species composition, and soil properties of a subtropical evergreen broad-leaved forest in Okinawa, Japan, were examined by establishment of plots at thirty sites. The forest was characterized by a relatively low canopy and a large number of small-diameter trees. Mean canopy height for this forest was 10 m and stands contained an average of 5400 stems-ha^-1 ( -〉 3.0 cm DBH); 64% of those stems were smaller than 10 cm DBH. The total basal area was 54.4 m^2-ha^-1, of which Castanopsis sieboldii contributed 48%. The forest showed high species diversity of trees. 80 tree species (≥ 3.0 cm DBH) from 31 families was identified in the thirty sampling plots. C. sieboldii and Schima wallichii were the dominant and subdominant species in terms of importance value. The mean tree species diversity indices for the plots were, 3.36 for Diversity index (H'), 0.71 for Equitability index (J') and 4.72 for Species richness index (S'), all of which strongly declined with the increase of importance value of the dominant, C. sieboldii. Measures of soil nutrients indicated low fertility, extreme heterogeneity and possible A1 toxicity. Regression analysis showed that stem density and the dominant tree height were significantly correlated with soil pH. There was a significant positive relationship between species diversity index and soil exchangeable K^+, Ca^2+, and Ca^2+/Al^3- ratio (all p values 〈0.001) and a negative relationship with N, C and P. The results suggest that soil property is a major factor influencing forest composition and structure within the subtropical forest in Okinawa. 展开更多
关键词 diversity index evergreen broad-leaved forest species composition soil nutrient soil-vegetation relation subtropical zone
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用6西格玛管理打造国际竞争力 被引量:1
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作者 陆云 《上海工商》 2002年第12期40-41,共2页
关键词 中国 六西格玛管理 企业管理 “黑带” “绿带” 国际竞争力
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一种行人“绿波带”控制方法及案例分析 被引量:1
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作者 赵力萱 陈宁宁 +1 位作者 洪波 罗强 《广东公安科技》 2017年第3期15-18,35,共5页
路段行人过街信号控制常采用"行人一次过街控制"和"行人二次过街控制"2种方式,但这2种控制方法都不适用于中央设有安全岛,且人流量和车流量都很大的较宽路段。本文提出新型行人"绿波带"控制方法来解决这... 路段行人过街信号控制常采用"行人一次过街控制"和"行人二次过街控制"2种方式,但这2种控制方法都不适用于中央设有安全岛,且人流量和车流量都很大的较宽路段。本文提出新型行人"绿波带"控制方法来解决这一问题,通过调整行人放行方式,精确计算行人过街所需时间,形成行人"绿波带",避免双向行人在中央行人安全岛冲突,消除瓶颈,提高行人通行效率,同时将滞留中央行人安全岛的行人数量降至最低,极大的减少了行人闯红灯的行为,保证行人过街的安全。 展开更多
关键词 行人“绿带” 交通信号控制 交通仿真
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The Chlorophyll Biosynthesis in Lotus Embryo Is Light-dependent 被引量:9
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作者 季宏伟 李良璧 匡廷云 《Acta Botanica Sinica》 CSCD 2001年第7期693-698,共6页
Angiosperms need light to synthesize chlorophyll, but lotus (Nelumbo nucifera Gaertn.) embryo was suspected to have the ability to form chlorophyll in the dark because lotus embryo can turn into green under the covera... Angiosperms need light to synthesize chlorophyll, but lotus (Nelumbo nucifera Gaertn.) embryo was suspected to have the ability to form chlorophyll in the dark because lotus embryo can turn into green under the coverage of four layers of integuments (cotyledon, seed coat, pericarp, lotus pod) which were thought impossible for light to pass through. The authors excluded this possibility based on two experimental results: First, enclosing the young lotus pod with aluminium foil, the growth of louts embryo continued, but the chlorophyll formation was seriously inhibited. A lot of protochlorophyllide, chlorophyll precursor, were accumulated, most of which were combined with LPOR (light dependent protochlorophyllide oxidoreductase). Second, DPOR (dark or light-independent protochlorophyllide oxidoreductase) was the enzyme necessary for chlorophyll synthesis in the dark. The genes encoding DPOR were conservative in many species, but no homologues could be found in lotus genome. Taken together, authers' results clearly demonstrated that lotus embryo synthesizes chlorophyll only through the light-dependent pathway. 展开更多
关键词 lotus embryo chlorophyll biosynthesis protochlorophyllide oxidoreductase
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Green Tourism in Mountain Regions-Reducing Vulnerability and Promoting People and Place Centric Development in the Himalayas 被引量:8
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作者 R. B. Singh D. K. Mishra 《Journal of Mountain Science》 SCIE CSCD 2004年第1期57-64,共8页
In recent years, mountain regions are attracting great attention to Indian tourists in general and foreign tourists in particular. The potential mountain resources for promoting green tourism are enormous in the form ... In recent years, mountain regions are attracting great attention to Indian tourists in general and foreign tourists in particular. The potential mountain resources for promoting green tourism are enormous in the form of natural and cultural heritage such as biosphere reserves, flora and fauna, lakes and rivers and traditional rural resources. In order to utilise tourism industry market, uncontrolled numbers of tourists and related haphazard infrastructural facilities in the vulnerable mountain regions pose serious environmental implications. The ecological pressures are threatening land, water and wild life resources through direct and indirect environmental impacts together with generation of solid and liquid wastes, so green tourism is emerging as an important task in order to develop new relationship between communities, government agencies and private sectors. The strategy focuses on ecological understanding, environmental protection and ecodevelopment. The major attributes of the green tourism include environmental conservation and education and distribution of income to local people based on strong partnership. Various knowledge systems go a long way for achieving the goals of the green tourism, which creates awareness about the value of environmental resources. Mountains have ecological, recreational, educational and scientific values, which need to be utilised in sustainable way. Various tourist activities and facilities need to be diversified in order to achieve multiple benefits including scientific field excursion, recreation in natural and cultural areas, community festivals and sport tourisms. Green tourism considers tourism development as an integral part of a national and regional development. The paper discusses the social, economic and environmental dimensions of the green tourism with particular reference to village tourism development programme taking empirical evidences from the Himalaya. Such programme also minimises biophysical and human vulnerability and risks in mountain regions. The environmental consciousness campaign and introduction of code through multi- purpose Tourist Resource Centres are gaining currency in above context. 展开更多
关键词 Mountain region green tourism development programme Kullu Himalaya
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迈向新城镇的美国
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作者 克来伦兹.斯坦恩 罗克全 《长春市委党校学报》 2013年第5期71-76,共6页
"花园城市"、"瑞得本体系"和"邻里单元"是设计规划和新城镇的建设理念。1929—1933年的"大萧条"之后,美国开始了大规模的公共设施的建设,这为城市建设理念的实施提供了恰当的契机。其中,"... "花园城市"、"瑞得本体系"和"邻里单元"是设计规划和新城镇的建设理念。1929—1933年的"大萧条"之后,美国开始了大规模的公共设施的建设,这为城市建设理念的实施提供了恰当的契机。其中,"河谷项目"和"绿带城镇"的规划与实施,是迈向美国新城镇建设的肇始,特别是"绿带城镇"建设在选址、总体规划、移民选择、商业与城市管理的布局和教育等诸多城镇要素为迈向美国新城镇提供了最好的范例。 展开更多
关键词 建筑理念 新城镇 “河谷项目” “绿城镇”
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Analysis and assessment of nickel and chromium pollution in soils around Baghejar Chromite Mine of Sabzevar Ophiolite Belt,Northeastern Iran 被引量:2
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作者 Eisa SOLGI Javad PARMAH 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第7期2380-2387,共8页
The key objective of this research was to estimate the Ni and Cr contents of soil around the Baghjar Chromite Mine(BCM)of Sabzevar Ophiolite Belt,Northeastern Iran,and assess the degree of soil pollution using the p... The key objective of this research was to estimate the Ni and Cr contents of soil around the Baghjar Chromite Mine(BCM)of Sabzevar Ophiolite Belt,Northeastern Iran,and assess the degree of soil pollution using the pollution indices.Soil samples(0-20 cm depth) were collected at various distances from the BCM.In the present research,heavy metals(Cr and Ni) in soil samples were analyzed by atomic absorption spectrometry to detect their concentrations and contour maps were produced to explain the metal spatial distribution.Also,the degree of metal pollution was quantified.The results indicate that the soils in the studied area are contaminated by Cr and Ni.The corresponding concentrations for Cr and Ni are(156.19±24.45) and(321.7±133.27) mg/kg,respectively,which exceed the corresponding maximum allowable concentrations in soils.The different indices demonstrate that soils around chromite mine are significantly contaminated with Cr and Ni,suggesting several times higher levels of toxic metals than normal ranges.The above results revealed that the heavy metal concentrations increase with increasing the distance from the mine and mining pollutants can be transported to long distances from their sources. 展开更多
关键词 ophiolite belt chromite mine spatial pattern geoaccumulation index pollution load index
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Evaluation and classification of residential greenbelt quality based on factor analysis & clustering analysis:An example of Xinxiang City,China 被引量:1
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作者 乔丽芳 张毅川 齐安国 《Journal of Forestry Research》 SCIE CAS CSCD 2008年第4期311-314,共4页
Five factors expressing greenbelt quality and one factor expressing quantity were adopted for evaluation of the residential greenbelt, and the AHP (Analytical Hierarchy Process) method was used to determine the valu... Five factors expressing greenbelt quality and one factor expressing quantity were adopted for evaluation of the residential greenbelt, and the AHP (Analytical Hierarchy Process) method was used to determine the value of factors. Thirty residential areas were selected as the samples. Two principal components were extracted and their expression was constructed by method of factor anlysis, therefore, quality evaluation of residential greenbelt was obtained. The accuracy of the function and implement quality classification toward the residential greenbelts in Xinxiang City were validated by clustering analysis method. The results showed that the greenbelt quality of fourteen residential areas was higher than the average level, of which eleven were newly-built residential areas. The 30 residential areas were classified into three types according to their greenbelt features and their formation by clustering analysis method. Finally rational proposal basing on aforesaid evaluating results was proposed for construction and renewal of residential greenbelt, upon which directive basis was provided for construction and renewal of residential greenbelt. 展开更多
关键词 residential area greenbelt quality EVALUATION factor analysis clustering analysis
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Characteristics of Wind Erosion and Deposition in Oasis-desert Ecotone in Southern Margin of Tarim Basin,China 被引量:7
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作者 MAO Donglei LEI Jiaqiang +3 位作者 ZENG Fanjiang RAHMUTULLA Zaynulla WANG Cui ZHOU Jie 《Chinese Geographical Science》 SCIE CSCD 2014年第6期658-673,共16页
The oasis-desert ecotone is a fragile ecological zone that is affected both by oasis and desert conditions. To understand the impact of the differences in wind power, and the influence of wind erosion and deposition o... The oasis-desert ecotone is a fragile ecological zone that is affected both by oasis and desert conditions. To understand the impact of the differences in wind power, and the influence of wind erosion and deposition on the ecotone, meteorological data and con- temporaneous wind erosion and deposition data were collected on the southern margin of Tarim Basin with serious sand-blown hazards. The wind velocity, average wind velocity, sand drift potential (DP), resultant sand drift potential (RDP), and sand transportation rate decrease significantly and successively across four landscape types with increasing vegetation coverage (VC). Flat surfaces and areas of shifting sandy ground experience intense wind erosion with fast movement of mobile sand dunes; semi-fixed sand areas experience ex- tensive wind deposition but only slight wind erosion; and fixed sand areas experience only slight wind erosion and deposition. Volume of wind erosion on bare newly reclaimed farmland is up to 6.96 times that of bare shifting sandy ground. Wind erosion volume per unit area and VC follow an exponential function relationship in natural conditions, while wind deposition volume per unit area does not conform to any functions which has close relationship with vary topography and arrangement patterns of vegetation besides for VC. The results indicate that the volume of wind erosion has a close correlation with VC, and different types and distribution patterns of topog- raphy and vegetation also profoundly influence the wind deposition volume in the field, and underground water tables in different land- scape types control the plant community distribution. Keywords: wind erosion; wind deposition; oasis-desert ecotone; vegetation coverage (VC); topography; Cele County 展开更多
关键词 wind erosion wind deposition oasis-desert ecotone vegetation coverage (VC) TOPOGRAPHY Cele County
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Preliminary Assessment of the Common Land Model Coupled with the IAP Dynamic Global Vegetation Model 被引量:1
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作者 ZHU Jia-Wen ZENG Xiao-Dong +1 位作者 LI Fang SONG Xiang 《Atmospheric and Oceanic Science Letters》 CSCD 2014年第6期505-509,共5页
The Common Land Model(CoLM) was coupled with the IAP Dynamic Global Vegetation Model(IAPDGVM), and the performance of this combined CoLMIAP model was evaluated. Offline simulations using both the original Common Land ... The Common Land Model(CoLM) was coupled with the IAP Dynamic Global Vegetation Model(IAPDGVM), and the performance of this combined CoLMIAP model was evaluated. Offline simulations using both the original Common Land Model(CoLM-LPJ) and CoLM-IAP were conducted. The CoLM-IAP coupled model showed a significant improvement over CoLMLPJ, as the deciduous tree distribution decreased over temperate and boreal regions, while the distribution of evergreen trees increased over the tropics. Some biases in CoLM-LPJ were preserved, including the overestimation of evergreen trees in tropical savanna, the underestimation of boreal evergreen trees, and the absence of boreal shrubs. However, most of these biases did not exist in a further coupled simulation of IAP-DGVM with the Community Land Model(CLM), for which the parameters of IAP-DGVM were optimized. This implies that further improvement is needed to deal with the differences between CoLM and CLM in parameterizations of landbased physical and biochemical processes. 展开更多
关键词 dynamic global vegetation model land surface model vegetation fractional coverage CLIMATE
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The Distribution and Variability of Simulated Chlorophyll Concentration over the Tropical Indian Ocean from Five CMIP5 Models 被引量:2
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作者 LIU Lin FENG Lin +3 位作者 YU Weidong WANG Huiwu LIU Yanliang SUN Shuangwen 《Journal of Ocean University of China》 SCIE CAS 2013年第2期253-259,共7页
Performances of 5 models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) in simulating the chloro-phyll concentration over the tropical Indian Ocean are evaluated. Results show that these models are abl... Performances of 5 models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) in simulating the chloro-phyll concentration over the tropical Indian Ocean are evaluated. Results show that these models are able to capture the dominant spatial distribution of observed chlorophyll concentration and reproduce the maximum chlorophyll concentration over the western part of the Arabian Sea, around the tip of the Indian subcontinent, and in the southeast tropical Indian Ocean. The seasonal evolution of chlorophyll concentration over these regions is also reproduced with significant amplitude diversity among models. All of 5 mod-els is able to simulate the interannual variability of chlorophyll concentration. The maximum interannual variation occurs at the same regions where the maximum climatological chlorophyll concentration is located. Further analysis also reveals that the Indian Ocean Dipole events have great impact on chlorophyll concentration in the tropical Indian Ocean. In the general successful simulation of chlorophyll concentration, most of the CMIP5 models present higher than normal chlorophyll concentration in the eastern equatorial Indian Ocean. 展开更多
关键词 Indian Ocean chlorophyll concentration CLIMATOLOGY seasonal variability interannual variability
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种树"种"出"和平奖"
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作者 史先振 《甘肃林业》 2004年第6期35-35,共1页
肯尼亚环境保护活动家旺加里·马塔伊女士10月8日荣膺2004年诺贝尔和平奖,她是自这一奖项1901年设立以来首位获奖的非洲女性.挪威诺贝尔委员会宣布的获奖理由是,作为肯尼亚环境和自然资源部副部长,马塔伊领导的环保组织"绿带运... 肯尼亚环境保护活动家旺加里·马塔伊女士10月8日荣膺2004年诺贝尔和平奖,她是自这一奖项1901年设立以来首位获奖的非洲女性.挪威诺贝尔委员会宣布的获奖理由是,作为肯尼亚环境和自然资源部副部长,马塔伊领导的环保组织"绿带运动"在非洲植树3000多万棵,并致力于争取妇女权力,改善环境和打击腐败. 展开更多
关键词 旺加里·马塔伊 2004年诺贝尔和平奖 环境保护 “绿运动” 植树造林 妇女权益
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Effect of Slash Burning on Nutrient Removal and Soil Fertility in Chinese Fir and Evergreen Broadleaved Forests of Mid-Subtropical China 被引量:19
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作者 YANG YUSHENG, GUO JIANFEN, CHEN GUANGSHUI, HE ZONGMING and XIE JINSHENGFujian Agriculture and Forestry University, Nanping 353001 (China) 《Pedosphere》 SCIE CAS CSCD 2003年第1期87-96,共10页
A Chinese fir forest (Cunninghamia lanceolata, CF) and an evergreen broadleaved forest (EB) located inFujian Province, southeastern China, were examined following slash burning to compare nutrient capital andtopsoil p... A Chinese fir forest (Cunninghamia lanceolata, CF) and an evergreen broadleaved forest (EB) located inFujian Province, southeastern China, were examined following slash burning to compare nutrient capital andtopsoil properties with pre-burn levels. After fire, nutrient (N, P and K) removal from burning residues wasestimated at 302.5 kg ha-1 in the CF and 644.8 kg ha-1 in the EB. Fire reduced the topsoil capitals of totalN and P by about 20% and 10%, respectively, in both forests, while K capital was increased in the topsoils ofboth forests following fire. Total site nutrient loss through surface erosion was 28.4 kg (N) ha-1, 8.4 kg (P)ha-1 and 328.7 kg (K) ha-1 in the CF. In the EB, the losses of total N, P and K were 58.5, 10.5 and 396.3kg ha-1, respectively. Improvement of soil structure and increase in mineralization of nutrients associatedwith increased microbe number and enzyme activities and elevated soil respiration occurred 5 days after fire.However, organic matter and available nutrient contents and most of other soil parameters declined one yearafter fire on the burned CF and EB topsoils. These results suggest that short-term site productivity canbe stimulated immediately, but reduced subsequently by soil and water losses, especially in South China,where high-intensity precipitation, steep slopes and fragile soil can be expected. Therefore, the silviculturalmeasurements should be developed in plantation management. 展开更多
关键词 chinese fir evergreen broadleaved forest nutrient removal slashburning soil fertility
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Thermal Response to Heat in Buildings with Green Covers for Tropical Climate: Green Facades and Green Roofs
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作者 Nuria Perez Gallardo Gustavo Zen de Figueiredo Neves +1 位作者 Adriano Rogerio Bruno Tech Francisco Arthur da Silva Vecchia 《Journal of Civil Engineering and Architecture》 2016年第8期919-931,共13页
The main aims of this paper were to study and demonstrate the benefits the plant systems can provide indoors in a critical heat day. This study proposed an experimental method to try to understand the thermal response... The main aims of this paper were to study and demonstrate the benefits the plant systems can provide indoors in a critical heat day. This study proposed an experimental method to try to understand the thermal response to heat of four different systems: a prototype called control (no vegetation) and three with different combinations of vegetation (green roofs and green facades) installed in a tropical climate region. The experiments were developed in four test cells with dimensions 2.0 m × 2.50 m× 2.71 m. Measurements of internal surface temperatures and internal air temperatures were collected with the use of specific equipment, a data logger (CR1000, Campbell Scientific Inc.), connected with two multiplexers 32 channels (416AM Campbell Scientific Inc.). Data were recorded over a year and a critical day heat was selected, which was September 24, 2015.The results show that the use of plant systems in buildings establishes a passive technique in reducing energy consumption because of the high incidence of summer solar radiation which is reduced and simultaneously, it maintains thermal internal conditions more pleasant than external ones, because of the best thermal behaviour, which was observed in the test cell with vegetation on both roofs and facades. The biggest difference between maximum internal air temperatures registered was 2 ℃. 展开更多
关键词 Green facades green roof thermal comfort bioclimatic architecture.
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Effect of precipitation condition on photosynthesis and biomass accumulation and referring to splash erosion status in five typical evergreen tree species in humid monsoon climatic region of subtropical hill-land
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作者 余蔚青 王云琦 +3 位作者 王玉杰 张会兰 王彬 刘勇 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第10期3795-3805,共11页
Negative effect of precipitation on plant photosynthesis was investigated in this work. Stomatal conductance, transpiration rate and net photosynthetic rate were measured before and after each precipitation event, res... Negative effect of precipitation on plant photosynthesis was investigated in this work. Stomatal conductance, transpiration rate and net photosynthetic rate were measured before and after each precipitation event, respectively, and the corresponding precipitation was recorded as well. Moreover, plant dry matter accumulation was counted at the end of our entire experiment. The results show that precipitation fully demonstrates its negative effect on plant photosynthesis under the condition of without water shortage. Although it has not been proved, leaf shape seems to be associated with this effect. Broad-leaved species are less influenced than coniferous and lanceleaf species no matter on the length of variation time or changes in variation values. The different situation among three broad-leaved species seems to illustrate that the effect is also related to the size of single leaf area. The correlation between precipitation and photosynthetic rate variation is analogous to the relationship between precipitation and splash erosion, and in the view of the relationship between plant photosynthetic characteristics and dry mass accumulation, it can be thought that it can reflect the negative impact of precipitation on plant growth by making use of splash erosion. Therefore, a section was added in the traditional plant biomass estimation algorithms by using eco-physiological models, and this was proved to enhance the accuracy of traditional estimation from preliminary verifications. 展开更多
关键词 PRECIPITATION leaf photosynthesis splash erosion dry matter net primary productivity
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Seasonal variations of group-specific phytoplankton cell death in Xiamen Bay, China
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作者 黄晓舟 柳欣 +3 位作者 陈纪新 肖武鹏 曹振 黄邦钦 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第2期324-335,共12页
The importance of phytoplankton cell death is being increasingly recognized, however, there are still no published reports on this in Xiamen Bay. In this study, the proportion of dead phytoplankton cells associated wi... The importance of phytoplankton cell death is being increasingly recognized, however, there are still no published reports on this in Xiamen Bay. In this study, the proportion of dead phytoplankton cells associated with environmental factors was assessed at a station in Xiamen Bay from December 2012 to December 2013, using a cell digestion assay, which is an effective method to analyze dead/ living ceils in complex natural phytoplankton communities. The percentages of dead cells (% DC) in the total phytoplankton in summer (16%+6%) were lower than those in winter (27%q-16%). Six groups of phytoplankton (G1-G6) were categorized by flow cytometry. These phytoplankton communities with diverse seasonal variations in % DC had different responses to environmental constraints. The main factors affecting mortality were temperature and salinity, while nutrient concentration showed little influence on phytoplankton death. Additio^aally, our results provide evidence that chlorophyll a concentrations had an inverse relationship with total phytoplankton % DC and viable cell abundance was more meaningful than total cells to explain variations in environmental parameters (such as Chl a). Moreover, the lowest mean % DC in total phytoplankton was 16%q-6% at our sample site, which is in a subtropical area with high water temperatures, full solar radiation, and rich nutrients. This indicates that phytoplankton cell death is a process that cannot be ignored. In summary, phytoplankton cell death is important in understanding the dynamics of phytoplankton communities and the fimctioning of subtropical ecosystems. 展开更多
关键词 cell death cell digestion assay PHYTOPLANKTON Xiamen Bay
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Low net primary productivity of dominant tree species in a karst forest, southwestern China: first evidences from tree ring width and girth increment 被引量:1
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作者 Jian Ni Haiyang Xu Libin Liu 《Acta Geochimica》 EI CAS CSCD 2017年第3期482-485,共4页
Aboveground net primary productivity(ANPP)of two dominant species, one deciduous tree(Platycarya strobilacea) and one evergreen tree(Machilus cavaleriei),was estimated based on the tree-ring width and the girth increm... Aboveground net primary productivity(ANPP)of two dominant species, one deciduous tree(Platycarya strobilacea) and one evergreen tree(Machilus cavaleriei),was estimated based on the tree-ring width and the girth increment as well as allometric functions in a karst evergreen and deciduous broadleaved mixed forest in central Guizhou Province, southwestern China. Results showed that the ANPP increased from 1961 to 2015, especially during the last 20–30 years, but with strong variations. The deciduous tree had higher ANPP than the evergreen tree according to two kinds of estimates by the tree ring and girth increment. The averaged ANPP for these two mature trees was 2.27 kg/individual/year, ca. 8 t/ha/year considering the normal stand density. Such karst forest productivity was lower than the natural subtropical forests in China and in the world. 展开更多
关键词 Biomass increment Tree ring Girth measurement Karst evergreen and deciduous broadleaved forest Allometric functions
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