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Chemical and Geological Control on Surface Water within the Shade River Watershed in Southeastern Ohio 被引量:1
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作者 Prosper Gbolo Dina L. López 《Journal of Environmental Protection》 2013年第1期1-11,共11页
The under-sampled middle and western branches of Shade River Watershed (SRW) in SE Ohio were investigated as part of the Ohio University—U.S. Environmental Protection Agency (EPA) STAR grant. This project was for mon... The under-sampled middle and western branches of Shade River Watershed (SRW) in SE Ohio were investigated as part of the Ohio University—U.S. Environmental Protection Agency (EPA) STAR grant. This project was for monitoring the quality of watersheds in Ohio and classifying them according to their physical, chemical, and biological conditions. Water samples, as well as field parameters, were taken at twenty-two sites for chemical analyses. The ions analyzed included Ca, Mg, Na, Fe, Mn, Al, NO3, SO4, HCO3, and total PO4, while the field parameters measured included pH, dissolved oxygen (DO), total dissolved solids (TDS), electrical conductivity (EC), and alkalinity. To assess the water quality within the SRW, the analyzed ions and field parameters were compared to the USEPA criteria for the survival of aquatic life. Analytical results showed that the watershed is dominated by Ca-HCO3waters with DO, Fe, Mn, and PO4being the main causes of impairment within the streams. The relatively elevated concentrations of manganese and less extent iron may be associated with the local geology and the acidic nature of the soils. The high alkalinity and calcium concentrations are due to the limestone geology. The elevated phosphate concentration may be due to anthropogenic sources, fertilizers, or contributions from phosphorus-rich bedrock that differs geochemically from other areas. 展开更多
关键词 shade River Watershed STAR GRANT Stream Water USEPA Criteria Mineral Stability Total Phosphate
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Comparative Study of Cooling under Shades of Some Forestry Tree Species with Respect to Ambient Temperatures
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作者 S. K. Gupta Jeet Ram +1 位作者 Hukum Singh Parmanad Kumar 《Journal of Geoscience and Environment Protection》 2018年第11期51-66,共16页
Trees create microclimate under their crowns in comparison to the outside ambient atmospheric temperature. Sun is the pivotal source of radiant energy reaching the earth atmosphere of which heat is more important than... Trees create microclimate under their crowns in comparison to the outside ambient atmospheric temperature. Sun is the pivotal source of radiant energy reaching the earth atmosphere of which heat is more important than light. The radiant energy reaches the ground without any barricade whereas the tree crown impedes it in reaching the earth’s surface. During the day, when insolation impinges on tree crown, a portion of it is reflected back to the space, other portion is absorbed by the canopy increasing the temperature of leaves and the remaining part reaches the ground penetrating through the crown. Thus, a significant coolness is experienced under the shade of trees in comparison to open sunshine, with qualitative variations. The cooling produced by trees under their shades varies with species to species due to variation in several anatomical, structural and physiological attributes of the species. Climate is changing more rapidly prominently due to human activities especially indiscriminate felling of trees and it is feared that it will create problems on availability of energy, water and food security. Economic value takes over ecological benefits in selection of species in plantation programmes and this might have been due to the lack of scientific data about varying effectiveness of ecological services bestowed by different species. In the present study, an endeavor has been made to understand as to how a tree is integrated to the effects on atmosphere and responses to changing conditions with respect to differential cooling produced by five selected forestry tree species belonging to different categories. Analysis of data has come out with gradation of the sample species in respect to their cooling effect in the atmosphere in terms of yearly, quarterly, monthly and diurnal basis. 展开更多
关键词 Solar Radiation Ambient Temperature TREE CROWN TREE shade COOLING Bio-Physical Processes
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STUDY ON SHADED TRANSDUCER FOR ACOUSTIC SCATTERING SYSTEM
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作者 王清池 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1999年第2期187-192,共6页
Ths paper introduces a transducer for measuring suspended sand particles, and a shading principle to eliminate the blind point in the near field of sound source axis. By adopting the front matching layer and back line... Ths paper introduces a transducer for measuring suspended sand particles, and a shading principle to eliminate the blind point in the near field of sound source axis. By adopting the front matching layer and back liner, the transducer’s fraquency band becomes 2. 1 times wider and the sensitivity 1. 6 times higher. The transducer is characterized by simple structure and portability. 展开更多
关键词 NEAR FIELD shaded TRANSDUCER suspended PARTICLE ACOUSTIC SCATTERING
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Weak stem under shade reveals the lignin reduction behavior 被引量:1
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作者 Sajad Hussain Nasir Iqbal +3 位作者 PANG Ting Muhammad Naeem Khan LIU Wei-guo YANG Wen-yu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2019年第3期496-505,共10页
Shades caused by neighboring tall plants in intercropping systems and weak sunlight are constraints in yield optimization. Shade influences many aspects of plant growth and development, leading to weak stems and susce... Shades caused by neighboring tall plants in intercropping systems and weak sunlight are constraints in yield optimization. Shade influences many aspects of plant growth and development, leading to weak stems and susceptibility to lodging. The plant cell wall is composed of certain proteins that allow the walls to stretch out, a process called cell wall loosening. Shade affects anatomical, morphological, and physiological traits of plants, thus reducing the physical strength of the stem in crops by changing the loosening of cell walls. Flexibility of cells facilitates further modifications such as wall loosening. In addition, shade stress causes increased internode length, and reduced xylem synthesis and photosynthesis. In shaded plants, lignin deposition in vascular bundles and sclerenchyma cells of stems is decreased. Lignin is a light sensitive phenolic compound and shading decreases the transcript abundance of several phenolic compound(flavone and lignin) related genes. Shading significantly influences the metabolic activities of phenylalanine ammonia-lyase(PAL), peroxidase(POD), 4-coumarate: CoA ligase(4 CL), and cinnamyl alcohol dehydrogenase(CAD) involved in lignin biosynthesis. Furthermore, suppression of lignin biosynthesis activities by abiotic stresses causes abnormal phenotypes such as collapsed xylem, bent stems, and growth retardation. In this review, the underlying mechanisms illustrate that under shading conditions reduced lignin content results in slender, weak, and unstable stems. The objective of this review is to elaborate lignin biosynthesis and its variability under stressful environmental conditions, especially in shade stress environments. The effects of shade on stem lignin metabolism are discussed on the morphogenetic, physiological, and proteomic levels. 展开更多
关键词 LIGNIN BIOSYNTHESIS shade stress LODGING STEM strength
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The Effects of Shade Tree Types on Light Variation and Robusta Coffee Production in Vietnam 被引量:2
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作者 Nguyen Van Long Nguyen Quang Ngoc +3 位作者 Nguyen Ngoc Dung Paul Kristiansen Isa Yunusa Chris Fyfe 《Engineering(科研)》 2015年第11期742-753,共12页
Vietnam is well-known as the second largest global coffee producer and the largest worldwide exporter of Robusta coffee. However, the Robusta coffee sector in Vietnam is facing many problems, including low quality, hi... Vietnam is well-known as the second largest global coffee producer and the largest worldwide exporter of Robusta coffee. However, the Robusta coffee sector in Vietnam is facing many problems, including low quality, high external inputs and water shortages as a result of shade tree eradication. A six-month research project was conducted that focused on effects of shaded tree types on variation of light intensity and aspects of Robusta production. Three shade tree species at different planting densities and shade provision were investigated, including 46 trees of Durian ha–1 (14% shade), 35 trees of Sennaha–1 (17% shade), and 60 trees of Leucaena ha–1 (34% shade), and unshaded site (Open) was used as a control. The study found that light intensity declined 50% with Durian, 58% with Senna and 60% with Leucaena compared with the Open site (2096 μmol?m–2?s–1). Within the coffee canopy, a significant decline in light intensity was observed from the top of the canopy to the bottom. The percentage of light at the middle (90 cm above ground) and bottom (30cm) levels of the coffee canopy was declined by 81% and 88% respectively for the Open site, and 86% and 92% for the Leucaena site. There were no differences in the number of flowers branch–1 tree–1 and fruit set between shaded and unshaded coffee sites. However, a significant difference in first fruit drop was observed. 展开更多
关键词 ROBUSTA COFFEE shaded COFFEE LIGHT Intensity COFFEE PRODUCTION VIETNAM
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Ameliorative Effect of Shade on Seedling Growth—Evidence from Field Experiment of <i>Vachellia farnesiana</i>(L.) Willd
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作者 Nurul Iman Suansa Hamad A. Al-Mefarrej 《American Journal of Plant Sciences》 2019年第1期12-23,共12页
The presence of species diversity in the ecosystem is an important aspect. Simply put, the loss of biodiversity and the formation of ecosystems into monocultures would reduce the productivity of the forest ecosystem t... The presence of species diversity in the ecosystem is an important aspect. Simply put, the loss of biodiversity and the formation of ecosystems into monocultures would reduce the productivity of the forest ecosystem than it has abundant diversity. This study conducted with a purpose to get the basic information regarding the effect of shade on the seedling growth. Understanding these relationships in the early years may reveal the important information, which will be helpful for managing and evaluating the silviculture practices. The study was conducted at Dirab Experiments and Agricultural Research Station, South of Riyadh. The experimental plot was managed under the corridor of Eucalyptus camaldulensis stands. Twenty seedlings of Vachellia farnesiana with relative similar height and diameter were planted in each block at a 5 × 5 m2 spacing in March 2017. Three different treatments were established and relatively categorized into Line 1 (without shade), Line 2 (shade until 09:00 a.m.), and Line 3 (shade until 11:00 a.m.). Eight months after planting, several morphological parameters were monthly assessed from November 2017 until April 2018. Also, the number of fruits was observed following the fruit’s season. Seedling growth variation as an effect of shading occurred between the lines of planting in this experiment. The seedling growth was significantly increased by shading treatment, even though target plant species (V. farnesiana) is categorized as intolerant species. Basically, shade helps to generate the favorable local environment for supporting plant growth. This treatment with an appropriate consideration might become an alternative practice for increasing plant productivity. 展开更多
关键词 Vachellia farnesiana UNDERPLANTING shade Tolerance Ameliorative EFFECT
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The molecular mechanism of shade avoidance in crops--How data from Arabidopsis can help to identify targets for increasing yield and biomass production 被引量:6
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作者 TANG Yun-jia Johannes Liesche 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第6期1244-1255,共12页
In order to prevent or counteract shading,plants enact a complex set of growth and developmental adaptations when they sense a change in light quality caused by other plants in their vicinity.This shade avoidance resp... In order to prevent or counteract shading,plants enact a complex set of growth and developmental adaptations when they sense a change in light quality caused by other plants in their vicinity.This shade avoidance response(SAR)typically includes increased stem elongation at the expense of plant fitness and yield,making it an undesirable trait in an agricultural context.Manipulating the molecular factors involved in SAR can potentially improve productivity by increasing tolerance to higher planting density.However,most of the investigations of the molecular mechanism of SAR have been carried out in Arabidopsis thaliana,and it is presently unclear in how far results of these investigations apply to crop plants.In this review,current data on SAR in crop plants,especially from members of the Solanaceae and Poaceae families,are integrated with data from Arabidopsis,in order to identify the most promising targets for biotechnological approaches.Phytochromes,which detect the change in light caused by neighboring plants,and early signaling components can be targeted to increase plant productivity.However,they control various photomorphogenic processes not necessarily related to shade avoidance.Transcription factors involved in SAR signaling could be better targets to specifically enhance or suppress SAR.Knowledge integration from Arabidopsis and crop plants also indicates factors that could facilitate the control of specific aspects of SAR.Candidates are provided for the regulation of plant architecture,flowering induction and carbohydrate allocation.Yet to-be-elucidated factors that control SAR-dependent changes in biotic resistance and cell wall composition are pointed out.This review also includes an analysis of publicly available gene expression data for maize to augment the sparse molecular data available for this important species. 展开更多
关键词 shade avoidance response phytochrome B Zea mays Solanum lycopersicum biomass carbon allocation
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Effect of shade stress on lignin biosynthesis in soybean stems 被引量:4
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作者 LIU Wei-guo REN Meng-lu +6 位作者 LIU Ting DU Yong-li ZHOU Tao LIU Xiao-ming LIU Jiang Sajad Hussain YANG Wen-yu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2018年第7期1594-1604,共11页
To clarify how shade stress affects lignin biosynthesis in soybean stem, two varieties, Nandou 12(shade tolerant) and Nan 032-4(shade susceptible) grew under normal light and shade conditions(the photosynthetical... To clarify how shade stress affects lignin biosynthesis in soybean stem, two varieties, Nandou 12(shade tolerant) and Nan 032-4(shade susceptible) grew under normal light and shade conditions(the photosynthetically active radiation and the ratio of red:far-red were lower than normal light condition). Lignin accumulation, transcripts of genes involved in lignin biosynthesis, and intermediates content of lignin biosynthesis were analyzed. Both soybean varieties suffered shade stress had increased plant heights and internode lengths, and reduced stem diameters and lignin accumulation in stems. The expression levels of lignin-related genes were significantly influenced by shade stress, with interactions between the light environment and variety. The gene of 3-hydroxylase(C3H), cinnamoyl-Co A reductase(CCR), caffeoylCoAO-methyltransferase(CCoAOMT), and peroxidase(POD) attributed to lignin biosynthesis under shade stress, and the down-regulation of these genes resulted in lower caffeic, sinapic, and ferulic acid levels, which caused a further decrease in lignin biosynthesis. Under shade stress, the shade tolerant soybean variety(Nandou 12) showed stiffer stems, higher lignin content, and greater gene expression level and higher metabolite contents than shade susceptible one. So these characteristics could be used for screening the shade-tolerant soybean for intercropping. 展开更多
关键词 Glycine max STEM shade stress lignin biosynthesis gene expression phenolic acids
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不同角度对X-Rite’s Shade Vision系统测量结果的影响 被引量:1
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作者 林芝 张秀华 +3 位作者 刘丽 朱形好 郑顺友 Y.LI 《口腔医学》 CAS 2006年第5期363-367,共5页
目的观察不同角度对X-Rite’s ShadeVision系统测量比色板结果的影响。方法将一副新的Vita16色比色板固定在粉红色的蜡中。X-Rite’s ShadeVision系统分别在平行于比色板唇面,5°、10°、15°向左右侧和切向、龈向倾斜时测... 目的观察不同角度对X-Rite’s ShadeVision系统测量比色板结果的影响。方法将一副新的Vita16色比色板固定在粉红色的蜡中。X-Rite’s ShadeVision系统分别在平行于比色板唇面,5°、10°、15°向左右侧和切向、龈向倾斜时测量颜色,以L*,a*,b*及Vita16色比色板色片颜色表示测量结果。计算ΔL,Δa,Δb和ΔE*ab,数据用单因素方差分析。结果向右倾斜5°、10°、15°时L*值分别减少0.22,0.97和0.93,而向左倾斜L*增加;垂直向角度改变时,L*值增加;最大的ΔL值在向龈向倾斜15°(2.84)和向切向倾斜15°(2.37),这导致相应位置出现最大的ΔE*ab(3.22±0.37)和(2.50±0.63),15°向左和右倾斜时,ΔE*ab分别为1.87±0.59和1.20±0.25。与其他位置比较,向龈向和切向15°时,ΔE*ab明显高(P<0.05)。结论X-Rite’sShadeVision测量时,正确的测量位置对获得准确的测量结果非常重要,角度的偏移,尤其是垂直向的倾斜会影响测量结果。 展开更多
关键词 XRites shadeVision系统
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乌龙茶覆盖遮荫技术的研究 被引量:10
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作者 翁伯琦 张文锦 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2005年第B06期16-21,共6页
进行了夏季乌龙茶园不同遮荫度遮荫的生态生理生化效应及其对茶树生长、产量和品质的影响研究.结果表明:与不遮荫的对照处理相比,遮荫后,(1)树冠层的白昼平均温度、日极端最高温度和温度日较差分别下降了1.47~4.29℃、3.95~7.26℃和3... 进行了夏季乌龙茶园不同遮荫度遮荫的生态生理生化效应及其对茶树生长、产量和品质的影响研究.结果表明:与不遮荫的对照处理相比,遮荫后,(1)树冠层的白昼平均温度、日极端最高温度和温度日较差分别下降了1.47~4.29℃、3.95~7.26℃和3.33~8.44℃;白昼平均相对湿度、日极端最低相对湿度分别增加了4.31%~12.31%和3.27%~12.62%,相对湿度日较差减少了3.58%~12.94%.(2)夏、暑梢1芽3叶含水率分别增加了4.57%~6.47%和2.24%~2.78%.(3)夏、暑梢叶绿素总量分别增加了0.5983~0.7019mg/dm2和0.3480~0.6050mg/dm2,增幅达41.70%~48.92%和52.38%~91.06%;叶绿素a增加38.96%~47.25%和50.94%~72.52%;叶绿素b增加了43.83%~54.58%和67.98%~155.81%;叶绿素a、b比值下降了0.1042~0.1868和1.10~3.54.(4)茶叶中茶多酚和咖啡碱含量明显降低,氨基酸含量明显提高,粗纤维含量显著减少,儿茶素组份得以优化.(5)适度遮荫有利于提高夏暑茶的产量和品质. 展开更多
关键词 湿 绿a 绿B
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CONTRACTED EFFECT OF BELL-SHADE SHAPE WELDING ARC AND ACCOMPANIED MAGNETIC FIELD WITH SPIRAL PIPE SHAPE 被引量:4
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作者 Yu Jianrong, Zhang Jiaying , Jiang Lipei, Jiao Xiangdong Beijing Institute of Petrochemical Technology, Beijing 102600 Department of Mechanical Engineering,Tsinghua University, Beijing 100084 Jia Changshen, Shi Yaowu Xi′an Jiaotong University, 《中国有色金属学会会刊:英文版》 CSCD 1997年第2期96-99,共4页
CONTRACTEDEFFECTOFBELLSHADESHAPEWELDINGARCANDACCOMPANIEDMAGNETICFIELDWITHSPIRALPIPESHAPE①YuJianrong,ZhangJi... CONTRACTEDEFFECTOFBELLSHADESHAPEWELDINGARCANDACCOMPANIEDMAGNETICFIELDWITHSPIRALPIPESHAPE①YuJianrong,ZhangJiaying,JiangLipei,... 展开更多
关键词 longitudinal magnetic field BELL shade SHAPE welding arc contracted effect ACCOMPANIED magnetic field SPIRAL PIPE SHAPE
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Phytochemical and anti-bacterial activity of epidermal glands extract of Christella parasitica (L.) H. Lev. 被引量:14
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作者 Paul Raj K Irudayaraj V +1 位作者 Johnson M Patric Raja D 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2011年第1期8-11,共4页
Objective:To study the morphology,biochemistry and bioactivity of the epidermal glands of the glandular morphotype of Christella parasitica(C.parasitica)(L.) H.Lev.Methods: Morphological studies on epidermal glands we... Objective:To study the morphology,biochemistry and bioactivity of the epidermal glands of the glandular morphotype of Christella parasitica(C.parasitica)(L.) H.Lev.Methods: Morphological studies on epidermal glands were earned out by using light microscope and scanning electron microscope.To prepare the extract,the shade-dried fronds of glandular morphotype were soaked in acetone.For antibacterial studies paper disc method was followed by using various pathogenic bacteria.Results:Detailed micromorphological,phytochemical and bioactivity studies on a medicinal fern C.parasitica(L.) H.Lev.showed its inlraspecific variation in antibacterial activity.The presence or absence of the epidermal glands was the key factor for antibacterial activity in the morphovariants of this species.The epidermal glands were orange-coloured,stalked and elongated ones of about 84.2μm×45μm,and distributed on the undersurface of cosla,coslules and veins in croziers,young and mature leaves.Frequency of glands varied from 15/cm on costa in mature leaves to 140/cm on costules in croziers.The acetone extract of the glands showed antibacterial activities and also toxic effect against mosquito larvae and tadpoles of frog.Preliminary phytochemical analysis and HPLC studies of the gland extract showed the presence of various kinds of terpenoids,alkaloids,tannins,saponins and flavonoids in it.Conclusions:The present study shows that epidermal glands of the glandular morphotype of C. parasitica(L.) H.Lev.have several bioactive compounds and such rare moiphovariant should be conserved in nature.The next step is to isolate the pure compounds and to screen the bioactivity of individual compounds of the epidermal glands. 展开更多
关键词 EPIDERMAL GLANDS Christella parasitica Bioactivity PHYTOCHEMICAL ACTIVITY Anti-bacterial ACTIVITY Morphology Biochemistry Glandular MORPHOTYPE Light microscope shade-dried frond Bioactive compound Morphovariant Preliminary PHYTOCHEMICAL analysis Gland EXTRACT Flavonoid
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New Improved Maximum Power Point Tracking Algorithm for Partially Shaded PV Systems 被引量:1
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作者 Dmitry Baimel Saad Tapuchi Nina Baimel 《Journal of Power and Energy Engineering》 2017年第9期55-63,共9页
The paper presents new MPPT algorithm for partial shading of series connected PV cells/modules. In the shaded condition, there is a problem of decrease in the total output power of the PV system. The proposed algorith... The paper presents new MPPT algorithm for partial shading of series connected PV cells/modules. In the shaded condition, there is a problem of decrease in the total output power of the PV system. The proposed algorithm aims to reduce this problem by active bypassing of the shaded cells. The algorithm senses the irradiance of each cell and performs calculation in order to decide if to actively bypass the shaded cell or not. Extensive simulation results proved that algorithm works and increases the output power under partial shading conditions. Furthermore, the algorithm becomes more efficient when the number of cells is increased. 展开更多
关键词 MPPT ALGORITHM PARTIAL SHADING Simulation
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遮阳系数对供暖与空调能耗影响差异的逐时解析 被引量:15
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作者 龙恩深 王勇 +1 位作者 肖益民 付祥钊 《暖通空调》 北大核心 2005年第6期46-51,共6页
以中国福州为例,从当地逐时气象数据入手,分析了建筑空调负荷及供暖负荷的所有时刻对应的逐时太阳辐射,用特征温度法研究当遮阳系数减小时各时刻建筑的空调与供暖能耗及相对变化(节能率)情况。研究发现,由于冬季有太阳辐射各时刻的供暖... 以中国福州为例,从当地逐时气象数据入手,分析了建筑空调负荷及供暖负荷的所有时刻对应的逐时太阳辐射,用特征温度法研究当遮阳系数减小时各时刻建筑的空调与供暖能耗及相对变化(节能率)情况。研究发现,由于冬季有太阳辐射各时刻的供暖能耗相对于无太阳辐射各时刻能耗比例很小,故遮阳措施对供暖总能耗的影响不显著,从而证明DOE2关于冬季遮阳系数减小对供暖能耗影响的结论值得商榷;由于夏季有太阳辐射各时刻空调能耗远大于无太阳辐射各时刻空调能耗,故遮阳措施对空调总能耗及节能率的影响非常显著,DOE2软件与特征温度法的结果是正确的;通过对福州全年各时刻空调供暖能耗、建筑负荷及节能率进行解析,揭示了看起来很分散的各时刻能耗及节能率差异数据总体上遵循的某种共性规律,供同行参考。 展开更多
关键词 2 DOP
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Comparative Study of Visual and Instrumental Analyses of Shade Selection
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作者 Jee-Ha Choi Ju-Mi Park +4 位作者 Seung-Geun Ahn Kwang-Yeob Song Min-Ho Lee Jae-Youn Jung Xinyu Wang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第1期62-67,共6页
The difference between visual and instrumental analyses of a shade selection on natural teeth was investigated. With visual analysis, five prosthodontist examined the middle third of the unrestored maxillary right cen... The difference between visual and instrumental analyses of a shade selection on natural teeth was investigated. With visual analysis, five prosthodontist examined the middle third of the unrestored maxillary right central incisor of a patient using VITAPEN classical and Vita Toothguide 3D-MASTER tooth shade guide. In instrumental analysis, one prosthodontist examined the same teeth using a spectrophotometer (ShadepilotTM, Degudent, Hanau-Wolfgang, Germany, software 2.40). Overall, instrumental analysis is more accurate and reproducible than a visual assessment. However, the difference is clinically acceptable. 展开更多
关键词 shade selection visual analysis instrumental analysis SPECTROPHOTOMETER
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遮荫对盐胁迫下油葵生长和光合生理的影响 被引量:2
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作者 任羽飞 封晓辉 +4 位作者 李静 郭凯 李伟柳 吴玉洁 刘小京 《中国生态农业学报(中英文)》 CAS CSCD 北大核心 2024年第4期687-700,共14页
盐碱地光伏系统下作物生长受到盐分和遮荫的双重影响,研究双重逆境下作物的生理响应对该系统内作物种植有重要指导意义。本研究以油葵(Helianthus annuus L.)为试验材料,采用盆栽试验,设3个盐分水平(在初始含盐量的基础上外加NaCl含量0 ... 盐碱地光伏系统下作物生长受到盐分和遮荫的双重影响,研究双重逆境下作物的生理响应对该系统内作物种植有重要指导意义。本研究以油葵(Helianthus annuus L.)为试验材料,采用盆栽试验,设3个盐分水平(在初始含盐量的基础上外加NaCl含量0 g·kg^(−1)、3 g·kg^(−1)和5 g·kg^(−1))和4个遮荫水平(0%、30%、60%和90%),探究遮荫对盐胁迫下油葵生长、光合特性、叶片解剖结构、生物量积累和分配及籽粒产量等的影响,为盐碱地光伏系统下开展作物种植提供理论依据。结果表明,不同盐分水平下,与不遮荫(遮荫水平0%)处理相比,遮荫会破坏油葵叶片光合反应中心,降低光能转换效率,减小叶片厚度和栅栏组织层,减少光合产物积累,进而抑制茎粗和花盘的生长,影响光合产物分配方向,最终降低籽粒产量;但适度遮荫下油葵会通过增加株高、增大叶面积、提高核酮糖-1,5-二磷酸羧化酶(Rubisco酶)和磷酸烯醇式丙酮酸羧化酶(PEPC酶)活性等方式提高叶片的光捕获能力,促进光合作用进行。不同遮荫水平下,与无盐分处理相比,轻(3 g·kg^(−1)NaCl)、重(5 g·kg^(−1)NaCl)度盐胁迫均会降低油葵的光合效率,抑制株高、茎粗、花盘和叶片的生长,减少光合产物的积累,最终降低籽粒产量,且不同盐胁迫浓度下油葵生长和光合生理特性在不同遮荫水平的变化规律不一致。其中,30%遮荫水平能显著提高轻度盐胁迫下油葵叶片的Rubisco酶和PEPC酶活性,减小叶片厚度,增大栅栏组织层,提高水分利用效率,进而提高油葵光合效率,促进油葵生长。研究表明弱光环境下油葵会通过改变自身形态、光合酶活性、光合产物分配等方式来应对环境胁迫,且遮荫能在一定程度上缓解盐胁迫对油葵造成的负面影响。其中,30%遮荫水平对缓解轻度盐胁迫引起的油葵光合能力降低和生长抑制的效果较好。 展开更多
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杉木闽楠异龄复层林中闽楠叶片形态适应特征 被引量:1
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作者 林智榕 李成珺 +3 位作者 陈水兰 陈志云 吴鹏飞 刘爱琴 《森林与环境学报》 CSCD 北大核心 2024年第2期113-119,共7页
以不同杉木闽楠复层林经营模式(TN40处理和TN60处理)中的闽楠叶片为研究材料,探讨不同处理对闽楠阴生叶、阳生叶的表型性状、解剖结构及气孔形态的影响。结果表明:从同一光环境不同叶型来看,TN40处理的闽楠阳生叶的叶片厚度、比叶重、... 以不同杉木闽楠复层林经营模式(TN40处理和TN60处理)中的闽楠叶片为研究材料,探讨不同处理对闽楠阴生叶、阳生叶的表型性状、解剖结构及气孔形态的影响。结果表明:从同一光环境不同叶型来看,TN40处理的闽楠阳生叶的叶片厚度、比叶重、栅栏组织厚度、中脉厚度较阴生叶分别增加了13.77%、9.86%、7.49%、11.79%,差异达显著水平(P<0.05);TN60处理的闽楠阳生叶的叶片厚度、叶组织密度、比叶重、气孔密度较阴生叶分别增加了6.32%、9.46%、8.70%、6.42%,差异达显著水平(P<0.05)。从同一叶型不同光环境来看,闽楠阳生叶在TN40处理下叶干物质含量、比叶重、上表皮厚度、栅栏组织厚度、海绵组织厚度、中脉厚度、气孔密度较TN60处理分别提高了6.13%、4.00%、11.62%、12.17%、15.22%、8.80%、9.00%,而叶片含水率、叶组织密度则分别降低了5.04%、3.97%,差异均达到显著水平(P<0.05);闽楠阴生叶在TN40处理下叶面积、叶干物质含量、气孔密度较TN60处理分别增加了5.52%、5.50%、11.25%,差异均达显著水平(P<0.05)。从闽楠叶片形态适应特征来看,TN40处理更适合闽楠的培育。 展开更多
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缓解城市过热:传统街巷的更新策略——以扬州南河下历史文化街区为例 被引量:2
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作者 王健 李胜才 郭红霞 《中国名城》 2024年第6期67-74,共8页
街巷作为历史文化街区主要的外部空间之一,除了最基本的交通功能外,也兼具社区交往、商业活动、娱乐活动及文化展示等功能,是城市物质与精神文化的载体。随着城市热岛效应的加剧,夏季过热的街巷空间直接影响到居民的生活品质和行为方式... 街巷作为历史文化街区主要的外部空间之一,除了最基本的交通功能外,也兼具社区交往、商业活动、娱乐活动及文化展示等功能,是城市物质与精神文化的载体。随着城市热岛效应的加剧,夏季过热的街巷空间直接影响到居民的生活品质和行为方式。通过借鉴前人有关街道热缓解策略的经验,并结合扬州历史文化街区的特点及夏热冬冷的气候特征,从疏导巷道、动态遮阳、增设街角公园、改善界面材质等方面,充分挖掘缓解历史文化街区传统街巷夏季过热的潜力。针对历史文化街区传统街巷热环境的研究不仅是对城市外部空间热环境研究的有益补充,同时对相同气候区的街巷更新也具有现实指导意义。 展开更多
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智能遮阳百叶眩光预测模型控制变量有效性分析 被引量:1
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作者 骆肇阳 齐轩宁 杨阳 《照明工程学报》 2024年第1期89-100,共12页
基于预测模型的智能遮阳百叶调控系统具有降低建筑室内眩光性能的能力,其智能性取决于调控方法。而调控方法的设计取决于对室内采光性能相关影响信息的思考。不同影响信息是调控反馈的依据,也是智能预测模型建构的基础。本研究利用机器... 基于预测模型的智能遮阳百叶调控系统具有降低建筑室内眩光性能的能力,其智能性取决于调控方法。而调控方法的设计取决于对室内采光性能相关影响信息的思考。不同影响信息是调控反馈的依据,也是智能预测模型建构的基础。本研究利用机器学习技术,对不同百叶控制变量展开眩光关联性分析,以及不同控制变量在眩光影响上的交互效应。利用XGBoost构建预测模型与展开特征选择,同时采用SHAP可解释方法进一步解析变量与眩光关联大小。研究结果表明,室内使用者所在区域与遮阳百叶之间距离、遮阳形变与眩光发生最为紧密,且互动性影响明显,同时太阳高度角也是遮阳百叶重要的响应信息。结论可为智能遮阳百叶调控系统设计和预测模型建构提供参考依据。 展开更多
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设施内不同遮阴处理对草莓生长和光合特性及产量品质的影响
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作者 黄宁旺 蒋琪玮 +8 位作者 王晶如 李浩 鹿高勇 张培培 薛俊龙 宫明永 赵林 肖伟 李玲 《中国果树》 2024年第5期68-74,共7页
以雪沁香草莓为试验材料,分别设置遮阴度30%、50%和70%处理,探究设施内不同遮阴处理对草莓生长、光合特性及产量、品质的影响。结果表明,遮阴后植株间温度和叶面光合有效辐射(PAR)均显著降低,遮阴处理使净光合速率(Pn)、气孔导度(Gs)、... 以雪沁香草莓为试验材料,分别设置遮阴度30%、50%和70%处理,探究设施内不同遮阴处理对草莓生长、光合特性及产量、品质的影响。结果表明,遮阴后植株间温度和叶面光合有效辐射(PAR)均显著降低,遮阴处理使净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、胞间CO_(2)浓度(Ci)的日变化曲线均由原来的“双峰”型变成了“单峰”型,且显著提高了叶绿素含量。30%遮阴处理下草莓植株的生长状态和果实产量均达到最佳,且对果实品质影响较小,而70%遮阴处理下各项指标均降至最差。综上,在设施内进行30%遮阴处理有助于设施草莓提质增产。 展开更多
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