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基于小口径望远镜的小行星测光研究
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作者 刘君达 梅苞 张金 《中国科技教育》 2017年第4期26-27,共2页
背景资料测光观测是探测小行星物理性质的重要手段。通过测光观测,可得到小行星的自转周期、自转轴指向、形状、色指数等信息,结合通过其他探测手段得到的数据,可以为研究太阳系起源、演化提供重要依据。另外,也可以为小行星的深空探测... 背景资料测光观测是探测小行星物理性质的重要手段。通过测光观测,可得到小行星的自转周期、自转轴指向、形状、色指数等信息,结合通过其他探测手段得到的数据,可以为研究太阳系起源、演化提供重要依据。另外,也可以为小行星的深空探测提供前期数据支持。 展开更多
关键词 色指数 太阳系起源 光变周期 自转轴 探测手段 光变曲线 观测目标 位角 比较星 较差测光
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彗星1962—C的观测
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作者 杜昇云 《北京师范大学学报(自然科学版)》 CAS 1963年第1期115-120,共6页
一九六二年四月九日到四月二十四日,在我校天文台对慧星1962—C进行了目视观测和照相观测,在前后半个月的时间内,共拍得20张照片。观测是在蔡司赤道仪上进行的,D=130mm,F=1950mm,放大率195倍,照相使用了赤道仪所附天体照相仪,D=63mm,F=2... 一九六二年四月九日到四月二十四日,在我校天文台对慧星1962—C进行了目视观测和照相观测,在前后半个月的时间内,共拍得20张照片。观测是在蔡司赤道仪上进行的,D=130mm,F=1950mm,放大率195倍,照相使用了赤道仪所附天体照相仪,D=63mm,F=270mm,照相底片的灵敏度为21/10 DIN。目视观测表明,这一慧星的结构是随着它远离太阳而逐渐清晰的,廿日以后。 展开更多
关键词 天体照相仪 照相底片 九六 彗头 光电测光 平方度 露光 消光系数 历表 比较星
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Comparison on Winter Wheat Yield Estimating Models Based on Radarsat-2 and HJ Satellite in Huaihe River Region 被引量:1
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作者 范伟 陈磊 +2 位作者 陈娟 闫洪凯 刘韬 《Agricultural Science & Technology》 CAS 2016年第4期1019-1023,共5页
The establishment of crop yield estimating model based on microwave and optical satellite images can conduct the mutual verification of the accuracy of the reported crop yield and the precision of the estimating model... The establishment of crop yield estimating model based on microwave and optical satellite images can conduct the mutual verification of the accuracy of the reported crop yield and the precision of the estimating model. With Shou County and Huaiyuan County of Anhui Province as the experimental fields of winter wheat producing areas, the linear winter wheat yield estimating models were established by adopting backscattering coefficient and Normalized Difference Vegetation Index(NDVI) based on images from the synthetic aperture radar(SAR)—RDARSAT-2 and HJ satellite photographed in mid-April and early May, 2014, and then comparisons were conducted on the accuracy of the yield estimating models. The accuracies of the yield estimating models established using co-polarized(HH) and cross-polarized(HV) modes of SAR in Jiangou Town, Shou County were 68.37% and 74.01%, respectively, while the accuracies in Longkang Town, Huaiyuan County were 63.10%and 69.10%, respectively. Accuracies of yield estimating models established by HJ satellite data were 69.52% and 66.43% in Shou County and Huaiyuan County, respectively. Accuracies of winter yield estimating model based on HJ satellite data and that based on SAR were closed, and the yield difference of winter wheat in the lodging region was analyzed in detail. The model results laid the foundation and accumulated experience for the verification, parameters correction and promotion of the winter wheat yield estimating model. 展开更多
关键词 Winter wheat yield estimating model Synthetic aperture radar RADARSAT-2 HJ satellite Model comparison
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分数应用题找标准量教学例谈
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作者 冷金华 《贵州教育》 1997年第12期44-44,共1页
分数应用题是小学数学教学的重要内容之一。分数应用题中的“数”与“量”都比较抽象,且数量之间的逻辑性、灵活性较强。因此,小学生在解答分数应用题时要比整数应用题图难得多。能否正确解答分数应用题。关键是否找对“标准量”,也就... 分数应用题是小学数学教学的重要内容之一。分数应用题中的“数”与“量”都比较抽象,且数量之间的逻辑性、灵活性较强。因此,小学生在解答分数应用题时要比整数应用题图难得多。能否正确解答分数应用题。关键是否找对“标准量”,也就是被看作单位“1”的量;这一点是学生学习分数应用题的难点。如何突破难点,把握关键? 一、从整数乘、除法应用题入手,找出规律,确定“标准量”。其基本形式有: 展开更多
关键词 分数应用题 标准量 教学例 小学数学教学 基本形式 除法应用题 单位“1” 女生 比较星 正确解答
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Study on the Molecular Genetic Alterations in Nasopharyngeal Carcinoma
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作者 Yixin Zeng 《Science Foundation in China》 CAS 2006年第2期38-40,共3页
Nasopharyngeal carcinoma (NPC) was mostly common in Guangdong Province and Guangxi Chuang Autonomous Region. This cancer jeopardized people's health in the above areas. In order to understand the mechanisms for NPC... Nasopharyngeal carcinoma (NPC) was mostly common in Guangdong Province and Guangxi Chuang Autonomous Region. This cancer jeopardized people's health in the above areas. In order to understand the mechanisms for NPC, and further promote NPC's early diagnosis and therapy, the molecular genetic analysis research of NPC in China and in its outbreak areas becomes an emergent topic. Since NPC is a rare disease in developed countries of Europe and America, the research in this field has not been well-recognized in these countries. Furthermore, 展开更多
关键词 nasopharyngeal carcinoma genetic aberration gene expression
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