随着特高压(UHV)输电工程的建设,特高压输电线路对邻近无线电台站高频信号的无源干扰是目前迫切需要解决的问题。针对矩量法求解输电线路无源干扰存在的计算量过大,无法求解线路对高频信号无源干扰的缺点,基于输电线路无源干扰面模型,...随着特高压(UHV)输电工程的建设,特高压输电线路对邻近无线电台站高频信号的无源干扰是目前迫切需要解决的问题。针对矩量法求解输电线路无源干扰存在的计算量过大,无法求解线路对高频信号无源干扰的缺点,基于输电线路无源干扰面模型,提出了采用一致性几何绕射理论(uniform geometrical theory of diffraction,UTD)求解输电线路对高频信号无源干扰的思想。根据一致性几何绕射理论中的边缘绕射和表面绕射模型,研究了铁塔角钢和导线面模型在高频入射线照射下的绕射场,并介绍了该绕射场的求解方法。结合具体的工程问题,对极高频信号的输电线路无源干扰问题进行了分析研究。经验证,采用UTD方法可以实现对输电线路高频信号无源干扰问题的求解,也可反映各种线路条件下无源干扰的变化趋势。展开更多
The Kamchatka Peninsula - situated in the Pacific ＂Ring of Fire＂ - has 29 active and over 4oo extinct volcanoes. Since it is situated in the northeastern extremity of Russia, in subarctic climate, the volcanic landf...The Kamchatka Peninsula - situated in the Pacific ＂Ring of Fire＂ - has 29 active and over 4oo extinct volcanoes. Since it is situated in the northeastern extremity of Russia, in subarctic climate, the volcanic landforms are overprinted by the 446 glaciers. This research focuses on the ltMutnaya catchment which drains the southern slopes of two active volcanoes： Avachinsky and Koryaksky. Those volcanoes are a permanent threat for the cities of Petropavlovsk and Elizovo, which are the 2 of 3 cities of the peninsula. Hence, most of the studies carriedout in the area dealt with the natural hazards and only few focus on landscape evolution. Thus, the purpose of this study was to elaborate a cartographic approach which integrates classic geomorphology with state of the art GIS and remote sensing techniques. As result, different landforms and related processes have been analysed and included geomorphologic map of the in the first general ltMutnaya catchment.展开更多
In this study, we explore the feasibility of optimizing ecosystem photosynthetic and respiratory parameters from the seasonal variation of the net carbon flux. An optimization scheme is proposed to estimate two key pa...In this study, we explore the feasibility of optimizing ecosystem photosynthetic and respiratory parameters from the seasonal variation of the net carbon flux. An optimization scheme is proposed to estimate two key parameters （V2max and Q10） by exploiting the seasonal variation in the net ecosystem carbon flux retrieved by an atmospheric inversion system. This scheme is implemented to estimate V25max and Q10 of the boreal ecosystem productivity simulator （BEPS） to improve its NEP simulation in the boreal North American region. Then, in situ NEE observations at six eddy covariance sites are used to evaluate the NEE simulations from BEPS with initial and optimized parameters. The results show that the performance of the optimized BEPS is superior to that of the BEPS with the default parameter values. These results implicate that it is possible to optimize ecosystem model parameters by different sensitivities of V25max and Q10 during growing and non-growing seasons through atmospheric inversion or data assimilation techniques.展开更多
文摘随着特高压(UHV)输电工程的建设,特高压输电线路对邻近无线电台站高频信号的无源干扰是目前迫切需要解决的问题。针对矩量法求解输电线路无源干扰存在的计算量过大,无法求解线路对高频信号无源干扰的缺点,基于输电线路无源干扰面模型,提出了采用一致性几何绕射理论(uniform geometrical theory of diffraction,UTD)求解输电线路对高频信号无源干扰的思想。根据一致性几何绕射理论中的边缘绕射和表面绕射模型,研究了铁塔角钢和导线面模型在高频入射线照射下的绕射场,并介绍了该绕射场的求解方法。结合具体的工程问题,对极高频信号的输电线路无源干扰问题进行了分析研究。经验证,采用UTD方法可以实现对输电线路高频信号无源干扰问题的求解,也可反映各种线路条件下无源干扰的变化趋势。
基金supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Community Framework Programme(FLUMEN,Project number 318969,FP7-PEOPLE-2012-IRSES)co-funded by Russian Scientific Foundation project nr.14-17-00155
文摘The Kamchatka Peninsula - situated in the Pacific ＂Ring of Fire＂ - has 29 active and over 4oo extinct volcanoes. Since it is situated in the northeastern extremity of Russia, in subarctic climate, the volcanic landforms are overprinted by the 446 glaciers. This research focuses on the ltMutnaya catchment which drains the southern slopes of two active volcanoes： Avachinsky and Koryaksky. Those volcanoes are a permanent threat for the cities of Petropavlovsk and Elizovo, which are the 2 of 3 cities of the peninsula. Hence, most of the studies carriedout in the area dealt with the natural hazards and only few focus on landscape evolution. Thus, the purpose of this study was to elaborate a cartographic approach which integrates classic geomorphology with state of the art GIS and remote sensing techniques. As result, different landforms and related processes have been analysed and included geomorphologic map of the in the first general ltMutnaya catchment.
基金supported by the National Basic Research Program of China(2010CB950703)the National Natural Science Foundation of China(41571338)
文摘In this study, we explore the feasibility of optimizing ecosystem photosynthetic and respiratory parameters from the seasonal variation of the net carbon flux. An optimization scheme is proposed to estimate two key parameters （V2max and Q10） by exploiting the seasonal variation in the net ecosystem carbon flux retrieved by an atmospheric inversion system. This scheme is implemented to estimate V25max and Q10 of the boreal ecosystem productivity simulator （BEPS） to improve its NEP simulation in the boreal North American region. Then, in situ NEE observations at six eddy covariance sites are used to evaluate the NEE simulations from BEPS with initial and optimized parameters. The results show that the performance of the optimized BEPS is superior to that of the BEPS with the default parameter values. These results implicate that it is possible to optimize ecosystem model parameters by different sensitivities of V25max and Q10 during growing and non-growing seasons through atmospheric inversion or data assimilation techniques.
