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试论秦汉初历法的置闰规则 被引量:5
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作者 李忠林 《四川大学学报(哲学社会科学版)》 CSSCI 北大核心 2009年第6期5-11,共7页
从史书和历简来看,秦至汉初的后九月存在置于无中气之月所在年和上一年两种情况,因而其历法置闰不是简单的归余于终。论者以为这是采取将某一节气恒出现在某月作为置闰之原则,亦即固定节气置闰法,但今出历简存在明显的反证。根据史载和... 从史书和历简来看,秦至汉初的后九月存在置于无中气之月所在年和上一年两种情况,因而其历法置闰不是简单的归余于终。论者以为这是采取将某一节气恒出现在某月作为置闰之原则,亦即固定节气置闰法,但今出历简存在明显的反证。根据史载和出土历简很容易将这一时段的所有闰年排出,从而说明了这一时期的置闰遵循一个既定的经验序列。 展开更多
关键词 汉初 四分术 置闰规则
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Measuring-Basis Encrypted Quantum Key Distribution with Four-State Systems 被引量:3
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作者 CHEN Pan LI Yan-Song +1 位作者 DENG Fu-Guo LONG Gui-Lu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第1期49-52,共4页
A measuring-basis encrypted quantum key distribution scheme is proposed by using twelve nonorthogohal states in a four-state system and the measuring-basis encryption technique. In this scheme, two bits of classical i... A measuring-basis encrypted quantum key distribution scheme is proposed by using twelve nonorthogohal states in a four-state system and the measuring-basis encryption technique. In this scheme, two bits of classical information can be encoded on one four-state particle and the transmitted particles can be fully used. 展开更多
关键词 quantum key distribution measuring-basis encryption four-state system
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Numerical Simulation of a Landfall Typhoon Using a Bogus Data Assimilation Scheme
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作者 LU Bing WANG Bin ZHAO Ying 《Atmospheric and Oceanic Science Letters》 2011年第4期242-246,共5页
A typhoon bogus data assimilation scheme (BDA) using dimension-reduced projection four-dimen-sional variational data assimilation (DRP-4-DVar),called DRP-BDA for short,is built in the Advanced Regional Eta Model (AREM... A typhoon bogus data assimilation scheme (BDA) using dimension-reduced projection four-dimen-sional variational data assimilation (DRP-4-DVar),called DRP-BDA for short,is built in the Advanced Regional Eta Model (AREM).As an adjoint-free approach,DRP-BDA saves time,and only several minutes are taken for the full BDA process.To evaluate its performance,the DRP-BDA is applied to a case study on a landfall ty-phoon,Fengshen (2008),from the Northwestern Pacific Ocean to Guangdong province,in which the bogus sea level pressure (SLP) is assimilated as a kind of observa-tion.The results show that a more realistic typhoon with correct center position,stronger warm core vortex,and more reasonable wind fields is reproduced in the analyzed initial condition through the new approach.Compared with the control run (CTRL) initialized with NCEP Final (FNL) Global Tropospheric Analyses,the DRP-BDA leads to an evidently positive impact on typhoon track forecasting and a small positive impact on typhoon inten-sity forecasting.Furthermore,the forecast landfall time conforms to the observed landfall time,and the forecast track error at the 36th hour is 32 km,which is much less than that of the CTRL (450 km). 展开更多
关键词 DRP-4-DVar TYPHOON BDA
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