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低地磁扰期间海南电离层F2层临界频率的观测与IRI预测结果的对比研究 被引量:4
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作者 王国军 史建魅 +1 位作者 王铮 王霄 《科学技术与工程》 北大核心 2016年第29期7-12,共6页
国际参考电离层模型(IRI)是非常有影响的电离层经验模型之一,利用该模型对我国东亚地区,尤其是海南低纬度地区,进行长期预测的效果尚未研究。通过对一个太阳活动周(2002-2012年)期间海南观测站(19.5°N,109.1°E)数字... 国际参考电离层模型(IRI)是非常有影响的电离层经验模型之一,利用该模型对我国东亚地区,尤其是海南低纬度地区,进行长期预测的效果尚未研究。通过对一个太阳活动周(2002-2012年)期间海南观测站(19.5°N,109.1°E)数字测高仪DPS4D观测到的电离层临界频率/〇F2在低地磁扰动条件下的月中值日变化、季节变化和年变化进行了分析;并与相应的IRI-2012模型预报值进行了对比研究。结果表明:①观测到的/〇F2存在着明显的冬季异常和半年异常现象,对太阳活动存在着明显的依赖关系;②IRI-2012模型预报值虽给出了海南/〇F2的基本观测特征,但细节上IRI模型预测值与观测值还是存在着地方时、季节和年度偏差,主要表现为:在太阳活动低年模型存在高估;在太阳下降年期间模型存在低估;在太阳活动较高时期模型存在明显的分季低估,冬、夏季高估;整体上,多数偏差率在±20%以内。偏差率较大的时段主要集中在0500-0800LT,这与以前研究结果基本一致。这些结果对进一步完善IRI模型,尤其是在中国低纬度地区/〇F2预测参数方面,具有重要的参考价值。 展开更多
关键词 国际参考电离层 F2层临界频率 低纬电离层
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LOCAL ONE-DIMENSIONAL ASE-I SCHEME FOR 2D DIFFUSION EQUATION
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作者 LIU XIAO-YU and ZHANG BAO-LIN(Department of Applied Mathemattes, Tsinghua Unive rsiap Beijing, China Laboratory Of Commutational Physics, IAPCM P.O. Box 8009, Beliing, China) 《Wuhan University Journal of Natural Sciences》 CAS 1996年第Z1期515-521,共7页
A local alternating segment explicit - implicit method for the solution of 2D diffusion equations is presented in this paper .The method is unconditionally stable and has the obvious property of parallelism. Some nume... A local alternating segment explicit - implicit method for the solution of 2D diffusion equations is presented in this paper .The method is unconditionally stable and has the obvious property of parallelism. Some numerical experiments show the method is not only simple but also more accurate. 展开更多
关键词 ASE LOCAL ONE-DIMENSIONAL ASE-I SCHEME FOR 2D DIFFUSION EQUATION
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Smartphones to Account for 2/3 of World's Mobile Market by 2020,Says New GSMA Intelligence Study
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《ZTE Communications》 2014年第3期45-45,共1页
11 September 2014, Hong Kong: Smartphones will account for two out of every, three mobile connections globally by 2020, according to a major new report by GSMA In- telligence, the research arm of the GSMA. The new st... 11 September 2014, Hong Kong: Smartphones will account for two out of every, three mobile connections globally by 2020, according to a major new report by GSMA In- telligence, the research arm of the GSMA. The new study, "Smartphone forecasts and assumptions, 2007- 2020", finds that smartphones account for one in three mobile conneetions today, representing more than two billion mobile connections. It forecasts that the number of smartphone connections will grow three-fold over the next six years, 展开更多
关键词 GSMA Smartphones to Account for 2/3 of World’s Mobile Market by 2020 Says New GSMA Intelligence Study World
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A NEW CLASS OF UNIFORMLY SECOND ORDERACCURATE DIFFRENCE SCHEMES FOR 2D SCALAR CONSERVATION LAWS 被引量:1
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作者 Juan Cheng(Department of Aerodynamics, Nanjing University of Aeronautics & Astronautics,Nanjing, China)Jia-zun Dai (Department of Mathematics, Physics and Mechanics, Nanjing University of Aeronautics & Astronautics, Nanjing, China) 《Journal of Computational Mathematics》 SCIE CSCD 1997年第4期311-318,共8页
In this paper, concerned with the Cauchy problem for 2D nonlinear hyperbolic conservation laws,we construct a class of uniformly second order accurate finite difference schemes, which are based on the E-schemes. By ap... In this paper, concerned with the Cauchy problem for 2D nonlinear hyperbolic conservation laws,we construct a class of uniformly second order accurate finite difference schemes, which are based on the E-schemes. By applying the conver gence theorem of Coquel-Le Floch [1], the family of approximate solutions defined by the scheme is proven to converge to the unique entropy weak L∞-solution. Furthermore, some numerical experiments on the Cauchy problem for the advection equation and the Riemann problem for the 2D Burgers equation are given and the relatively satisfied result is obtained. 展开更多
关键词 Math A NEW CLASS OF UNIFORMLY SECOND ORDERACCURATE DIFFRENCE SCHEMES FOR 2D SCALAR CONSERVATION LAWS high Ph
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CALCULATIONS OF RIEMANN PROBLEMS FOR 2-D SCALAR CONSERVATION LAWS BY SECOND ORDER ACCURATE MmB SCHEME
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作者 Yang Shu-li(Institute of Applied Mathematics, Academia Sinica, Beijing, China) 《Journal of Computational Mathematics》 SCIE CSCD 1994年第4期339-351,共13页
Numerical solutions of Riemann problems for 2-D scalar conservation law are given by a second order accurate MmB (locally Maximum-minimum Bounds preserving) scheme which is non-splitting. The numerical computations s... Numerical solutions of Riemann problems for 2-D scalar conservation law are given by a second order accurate MmB (locally Maximum-minimum Bounds preserving) scheme which is non-splitting. The numerical computations show that the scheme has high resolution and non-oscillatory properties. The results are completely in accordance with the theoretical solutions and all cases are distinguished efficiently 展开更多
关键词 MATH CALCULATIONS OF RIEMANN PROBLEMS FOR 2-D SCALAR CONSERVATION LAWS BY SECOND ORDER ACCURATE MmB SCHEME
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