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近地卫星陨落期地球反照系数估计
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作者 李强 张烨 +2 位作者 田凯 祝俊淞 段崇雯 《光学精密工程》 EI CAS CSCD 北大核心 2018年第4期796-806,共11页
为了研究地球反照的可见光对太阳电池阵电流在卫星陨落期间的影响程度,进行阵电流的地球反照系数估计。以运行在300km高度、降交点地方时约10:30AM的某太阳同步轨道近地卫星陨落为例,在讨论卫星轨道半长轴、倾角、光照角、降交点地方时... 为了研究地球反照的可见光对太阳电池阵电流在卫星陨落期间的影响程度,进行阵电流的地球反照系数估计。以运行在300km高度、降交点地方时约10:30AM的某太阳同步轨道近地卫星陨落为例,在讨论卫星轨道半长轴、倾角、光照角、降交点地方时等参数漂移的基础上,重点分析卫星太阳电池阵电流和温度的变化,并对电流进行正弦曲线拟合,进而建立地球反照系数的估计模型,最后用卫星陨落期间的遥测数据进行检验。结果表明,卫星自300km轨道高度向100km轨道高度陨落期间,地球反照系数先由0.21逐渐变大,最大值接近0.40,后又逐渐变小至0.20附近;对估计值的二次曲线拟合结果表明,在轨道高度210~270km这一区间,地球反照对于太阳电池阵的作用最强,对应的地球反照系数极大值约为0.28,作用最强的中心区域可能在250km轨道高度附近。估计结果可应用于在轨航天器长期管理的遥测诊断、能源估计与预测、器件健康状态评估以及可见光载荷应用等方面。 展开更多
关键词 近地卫星 地球反照 最小二乘估计 太阳电池阵电流 卫星遥测
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PROSPECTING FOR SILVER STRIKING PLATINUM: Our First LEED Project
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作者 James MacGillivray 《Journal of Green Building》 2010年第4期78-90,共13页
Prospecting demands positive future orientation,hope,sometimes not even knowing what it is you might discover.We were hopeful prospectors on our first LEED project,not exactly sure what we might strike.We sought silve... Prospecting demands positive future orientation,hope,sometimes not even knowing what it is you might discover.We were hopeful prospectors on our first LEED project,not exactly sure what we might strike.We sought silver sustain­ability for the University of New Mexico(UNM)College of Education Building(COE);what we discovered was even more precious and rare,platinum.Getting there entailed chipping away at each sustainable LEED credit until we hit pay dirt,the first publicly-funded and second LEED Platinum building in New Mexico.Gregory T.Hicks&Associates P.C.Architects was contracted by UNM to design a LEED Silver Certified build­ing for its new COE Administration and Classroom Building,Phase 1.All new,state-funded buildings in New Mexico must achieve a minimum LEED Silver certification as mandated by Governor’s Executive Order.Two of our staff,Jim MacGillivray and Jay Davis,are LEED APs,and our Principal,Gregory T.Hicks,has taken several USGBC courses,but this being our first LEED project,we participated in additional study in LEED certification and sustainable design.We also hired an experienced sustainable design specialist to serve as our LEED AP,our lead prospector,Susan Barnett.Not knowing how easy or difficult it might be to achieve LEED Silver,the prudent approach was to strive for as many points as possible,so that if we lost a few points along the way we would still fulfill the obligations of our con­tract.UNM COE and other UNM staff championed this approach.Our initial strategy targeted LEED credits with minimal cost,those almost free,logical modifications that improve sustainability.Next,we focused on achieving four“Innovation in Design”credits,searching for ideas that would involve minor costs or creative design endeavor.UNM COE committed to a photovoltaic system for educational and research purposes as well as to purchase a renewable energy certificate.Our initial venture targeted up to 48 possible points,comfortably within Gold territory.We submitted our project to USGBC for design review as the project went out to bid.The design review denied a few points in some areas,but serendipitously awarded a few extra points in other areas.UNM COE supported the prospects of achieving Gold so we provided additional information to successfully appeal denied credits,which brought us back up to a potential of 48 points,assuming targeted points were awarded during the construction review.At this point we knew we would certainly achieve Silver,possibly Gold.Midway through construction,the COE Dean,Richard Howell,and COE Chief of Staff,Diane Gwinn,asked us if there might be a way to earn just 4 or more points to reach the 52 required for LEED Platinum.Steve Chavez,UNM Project Manager,strongly championed this effort.This seemed difficult,if not impossible at this juncture in the project,but we met with COE,UNM engineers,design engineers,LEED AP,and the contractor to brainstorm pos­sibilities.We came up with eight possibilities,but not all were affordable,practical,or supported,so we whittled the eight down to five,but just before the construction review we lost one of the five,so we tried for four.When the USGBC completed their construction review,we learned we had scored 52 points awarded LEED Platinum certification.Partnership of UNM COE,architect,engineers,LEED APs,and contractor created this success through a relentless“can-do”attitude throughout the project,plus some luck.Boring down deeply,we sought Silver and struck Platinum.This narrative is organized according to the USGBC LEED credit rating system and highlights the sustainable accomplishments of the project along with lessons learned.tech­. 展开更多
关键词 site stewardship storm water infiltration habitat low-albedo ultra-low-flow optimized energy high performance light spectrum enhanced commissioning peak performance
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城市异质植被的覆盖度估算模型比较研究 被引量:1
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作者 王敏 付迎春 《遥感技术与应用》 CSCD 北大核心 2015年第2期364-369,共6页
植被覆盖度是城市生态环境评价的一个重要指标。针对亚热带城市异质植被覆盖特征,选择像元尺度的植被指数(NDVI)转换模型、亚像元尺度的植被—土壤两端元模型(V-S Model)和植被—高—低反射率三端元模型(V-H-L Model)在TM影像上估算植... 植被覆盖度是城市生态环境评价的一个重要指标。针对亚热带城市异质植被覆盖特征,选择像元尺度的植被指数(NDVI)转换模型、亚像元尺度的植被—土壤两端元模型(V-S Model)和植被—高—低反射率三端元模型(V-H-L Model)在TM影像上估算植被覆盖度,并结合野外实地调查对比验证3种模型的估算精度及其适用性。结果表明模型尺度和背景亮度对植被覆盖度估算有着不同程度的影响。NDVI转换模型整体高估覆盖度为27%,V-S模型和V-H-L模型整体低估覆盖度分别为23%和5%;验证结果证明:NDVI转换模型对高密度(】60%)植被的估算结果最好,低估4%;V-H-L模型对中密度(40%~60%)和低密度(【40%)植被的估算结果最优,仅低估2%,并受背景亮度的影响最小。因此,NDVI转换模型适用于高密度植被覆盖度的估算,亚像元尺度下的V-S模型和V-H-L模型适用于低、中密度植被覆盖度的估算,并以V-H-L模型估算较为准确。 展开更多
关键词 植被覆盖度 植被指数转换模型 两端元模型 三端元模型 亮度
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