Subjects: Geosciences >> Geography submitted time 2021-04-23 Cooperative journals: 《干旱区研究》
Abstract：选择古尔班通古特沙漠的北部（一号点）、中部（二号点）、南部（三号点）3个不同样点的裸沙和藻结皮、地衣结皮与苔藓结皮3种生物结皮类型，对比研究了草本植物多样性的差异性及其主要环境影响因素。结果表明：（1）不同生物结皮类型的土壤理化性质有明显差异，土壤有机质、全氮、全磷、全钾含量以及黏粒、粉粒和细沙的含量随生物结皮演替显著上升，而中沙和粗沙的含量呈显著下降趋势，在沙漠不同区域呈现明显的空间异质性，二号样点中裸沙和藻结皮的养分含量和pH明显低于一号点和三号点。（2）草本植物的物种丰富度和Shannon-Wiener指数随生物结皮发育呈明显上升趋势，草本植物的物种组成、群落结构在不同类型生物结皮和沙漠不同区域均具有显著差异。（3）在土壤理化特征中，有机质、速效P和全K含量，以及pH和粉粒含量是影响草本植物分布的关键因子。（4）不同类型生物结皮之间的微地形和种类组成差异、种子生物学特性以及生物结皮在不同尺度下的土壤环境异质性共同影响草本植物在生物结皮中的物种组成和丰度，最终导致草本植物群落结构在生物结皮中的演替变化。
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： Temperature control is a simple and effective way to improve the system stability of the totalpower-type microwave radiometer,the full-polarimetric microwave radiometer can achieve high precision measurement for retrieving the sea surface wind vector by the method.Using a 23.8GHz digital-correlation full-polarimetric microwave radiometer,considering the effects of temperature on calibration of the polarimeter and adopting a special temperature control scheme,a constant temperature control system was designed to make the radiometer work stably.The experimental results show that the constant temperature control scheme can make the radiometer work in a stable state which can simplify the calibration process, make the calibration cycle longer and ensure the accuracy requirement of the calibration.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-03
Abstract： A mould method used in polarized wire grid fabrication is proposed.The grids with analytical and computer simulation analysis method is designed.A variety of specifications,different aperture and grid frame materials for microwave/millimeter wave band used the mould method is produced.This series of polarized wire grid is tested by the liquid nitrogen environment,mechanical and electrical performance test.The results show that the polarized wire grid has strong environment adaptability,high mechanical precision and excellent electrical performance,and can meet the demand of practical application,which develop a new method for millimeter wave polarized wire grids localization.
Peer Review Status:Awaiting Review
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