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引入通径分析对土壤有机碳与土壤团聚体稳定性之间的关系进行定量分析。结果表明：在各粒级团聚体中，5~10 mm和3~5 mm团聚体是影响土壤有机碳含量的主导因子，这与许多研究者在黄土高原、红壤和水稻土中的研究结果相一致，说明引用通径分析团聚体与土壤有机碳含量的关系是合理可行的。同简单相关系数和多元回归分析相比，用通径分析得出的各原因变量的决定系数能够用来相互比较，能分析其对土壤有机碳含量影响的大小。
This article analyses the relationship between soil organic carbon and soil aggregate stability with Path analysis. It turned out that: In the graded aggregate, 5 - 10 mm and 3 - 5 mm aggregate is the dominant factor affecting soil organic carbon content. This is consistent with the findings of many researchers in the Loess Plateau, red soil and paddy soil. It illustrates that reference to Path analysis aggregates and soil organic carbon content is reasonable and feasible. Compared with simple correlation coefficient and multiple regression analysis, the coefficient of determination of the reasons for variable by path analysis can be used to compare to each other, and to analyze its impact on soil organic carbon content size.
Research on nonlinear dynamic model of Micro Air Vehicle (MAV) plays an important role in MAV design. Its special design in configuration and large flight envelope make it more different from other aircrafts in aerodynamic characteristics. The flight dynamic model of the dual rotor MAV was established in MATLAB/Simulink environment based on research to the aerodynamic of the rotor and wing. Unsteady ele-ment theory was used to analyze the lift, drag, and moment of the rotor. The lift line theory was used to re-search the aerodynamics of the wing, fuselage, horizontal and vertical tails. The aerodynamic interference between propeller and wing was considered. At last, the MAV flight performance was calculated and trimmed in various flight modes. The results show that elevator has enough control authority to change the flight con-dition in the whole flight envelop and the MAV can hover, fly slowly in helicopter mode and fly rapidly in wing-borne mode.