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Collected by means of a high-altitude scientific balloon and a self-made automatic sample collector,a total of 276 dust grains were selected for the study of shape,grain size and optical property.Some of the grains were examined by X-ray diffraction and electrom microprobe techniques,The stratospheric dust grains can be classified as 6 types:cosmic dusts,cosmic dusts(?),microtektite,natural pollutants,artificial pollutants and the unknown substances.The different types of dust grains have different characters and distinguishing symbols.Widespread in the space of the solar system,cosmic dusts are the initial substances of the solar system and ,to some degree,have recorded a great wealth of information on the early history of the solar system.So they have become one of the important objects in the field of cosmochemistry at present time,Since the 1960‘s,scholars of many countries have collected cosmic dusts both in the space near the earth(using rock ets,space probes and space shuttles)and in the stratosphere (using high-altitude balloons or U-2air planes).According to the shape(the scanning electron microimage),element composition(the energy-dispersive X-ray spectrum)and optical properties of dust grains,the substances in the stratosphere can be classified as 5 types:cosmic dusts,alumina spheroids,terrestrial artificial pollutants,terrestrial natural pollutants and unknown substances(CDPET,1982). 相似文献
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Feng Bojun Huang Guoliang Liu Tianwei
Associale Professor Shanghai Jiao Tong University Shanghai Engineer Shanghai Jiao Tong University Shanghai 《中国海洋工程》1995,(4)
Articulated buoys become more and more popular by the marine management departments as a new type of aids to navigation, for they possess an excellent hydrodynamic performance with small static heel angle in wind and current and small rolling in wave and accurate position. The structure of articulated buoys and calculation method of their hydrodynamic performance are introduced in this paper. A scries of experiments has been conducted in the State Key Laboratory of Ocean Engineering of China and useful results achieved for providing a design optimization basis. 相似文献
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基于SWAN雷达拼图产品在暴雨过程中的对流云降水识别及效果检验 总被引:2,自引:2,他引:0
本文基于SWAN雷达拼图产品,选取了组合反射率因子、组合反射率因子水平梯度、回波顶高及垂直累积液态水含量作为识别参数,采用模糊逻辑法对暴雨过程中的对流云与层状云降水进行了分类试验,对发生在重庆的12次区域性暴雨天气过程分类结果进行了验证。并以ADTD地闪资料作为对流云降水的实况观测数据,分别采用了四种不同半径的空间匹配与四种不同时间匹配方式对识别出的对流云降水产品进行了定量检验。检验结果显示:随着空间匹配半径的增大,正确率明显提高,而6 min地闪相对于6 min拼图产品提前6、3、0 min及滞后3 min四种时间匹配方式,其正确率变化很小。对于12次暴雨过程的总体评分较高,检验方法具有清楚的物理意义,在不同的时空匹配方式下的评分结果符合实际情况,同时说明对流云与层状云降水分类效果较好,也是对对流云降水识别定量检验的一次探索。 相似文献
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通过对后大雪金矿13件光片的系统观察统计及电子探针分析,研究了金矿物的赋存状态,形态和粒度,化学成分,金的成色等特征及其变化规律,并分析探讨了其在矿床成因,成矿远景评价等方面的应用和意义。 相似文献
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以江苏宝应生态渔业光伏发电"领跑者"示范基地为研究对象,定量分析了不同辐射指标对渔光互补光伏发电效益的影响机制.结果表明:太阳辐射对渔光互补光伏电站发电效益有着显著影响,且存在季节性波动,在夏秋季日并网峰值及发电量较大,稳定性较高,而冬春季发电效益和稳定性较差;太阳辐射指标与日并网功率最大值相关性较高,且呈明显对数关系,而日发电量与太阳辐射指标呈明显线性关系;不同月份并网功率最大值和发电量与平均辐照度、最大辐照度和累计辐照量均呈正相关关系,影响月并网功率峰值最为明显的是最大辐照度,而影响月发电量最为明显的指标是有效利用小时数.通过研究发现,在该地区开展光伏发电功率预测和前期太阳能资源开发利用评估时,可采用平均辐照度、最大辐照度、日累计辐照量3个指标作为参考指标. 相似文献
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为了解浙江省及省内主要海水养殖区的自身污染状况,文章利用2005—2021年《浙江省渔业经济统计资料》及《第一次全国污染源普查水产养殖业污染源产排污系数手册》中部分养殖品种的产污系数等数据对浙江省海水养殖活动产生的污染量进行初步评估,并经过换算将不同种类的污染物统一用等标污染负荷表示。同时对浙江省主要沿海城市产生等标污染负荷情况及海水养殖产量进行时空演化分析。结果显示,2005—2021年浙江省海水养殖等标污染负荷量累计超过70亿m3/a。总体趋势为先波动上升,然后连续上升。等标污染负荷最高地区是宁波市,污染负荷量累积达271 769.2万m3/a,其次分别为台州市、舟山市和温州市。从品种角度来看,贝类产生等标污染负荷最高;从养殖方式来看,筏式养殖和底播产生等标污染负荷最高。时空演化分析表明,浙江海水养殖业自身污染与海水养殖产量变化基本同步,等标污染负荷与海水养殖产量都呈现明显的增长态势。 相似文献
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