The Liangshan and Qixia formations in the Sichuan Basin of central China were formed in the earlier middle Permian. Based on outcrop observation of the Changjianggou section at Shangsi, Guangyuan region and 3 rd -orde...The Liangshan and Qixia formations in the Sichuan Basin of central China were formed in the earlier middle Permian. Based on outcrop observation of the Changjianggou section at Shangsi, Guangyuan region and 3 rd -order sequence division in typical drillings, one-dimensional spectrum analysis has been used to choose the better curve between the natural gamma ray spectrometry log（ln （Th/K）） in Well-Long17 and the gamma ray log（GR） in Well-Wujia1, respectively, for identifying Milankovitch cycles in Sequence PSQ1 which comprises the Liangshan and Qixia formations, and then to identify the variation in the Milankovitch cycle sequences. On this basis, the system tract and 4 th -order sequence interfaces in Sequence PSQ1 were found via two-dimensional spectral analysis and digital filtering. Finally, a high-frequency sequence division program was established. Among these cycles, long eccentricity （413.0 ka） and short eccentricity （123.0 ka） are the most unambiguous, and they are separately the major control factors in forming 4 th -order （parasequence sets） and 5 th -order （parasequences） sequences, with the average thicknesses corresponding to the main cycles being 11.47 m and 3.32 m in Well-Long17, and 14.21 m and 3.79 m in Well-Wujia1, respectively. In other words, the deposition rate in the beach subfacies is faster than that of the inner ramp facies. The ln（Th/K） curve is more sensitive than the GR as the index of relatively ancient water depth in carbonate deposition. One-dimensional spectrum analysis of ln（Th/K） curve could distinguish the Milankovitch cycle sequences that arose from the Precession cycle （20.90 ka）, with a much higher credibility. Sequence PSQ1 in Well-Long17 contains 10 4 th -order sequences, and the growth span of Sequence PSQ1 consisting of the Liangshan and Qixia formations is about 4.13 Ma. The single deposition thickness of the long eccentricity cycle sequence has the characteristics of thinning and then thickening in the two-dimensional spectrum, which could be used to identify the system tract interface of the 3 rd -order sequence. The precession sequence thickness remains stationary. As a result, the early deposition rate in the mid-Permian of the Sichuan basin was very slow, remaining nearly stationary, and this reflects a sustained depositional environment. Whole-rock carbon and oxygen isotope curves could also prove this point. Milankovitch cycle sequence studies provide a basis for paleoenvironmental analysis and, as such, can be used to analyze ancient climate change, calculate deposition rate and deposition time, and carry out fine isochronous stratigraphic correlation.展开更多
K-th number query是计算机算法中的一个基础问题,被广泛作为很多算法实现的重要步骤。对该问题进行了深入研究,并找到了单询问渐近时间复杂度最优的算法。目前一般对于多询问的K-th number query问题使用平衡二叉树解决,询问的时间复...K-th number query是计算机算法中的一个基础问题,被广泛作为很多算法实现的重要步骤。对该问题进行了深入研究,并找到了单询问渐近时间复杂度最优的算法。目前一般对于多询问的K-th number query问题使用平衡二叉树解决,询问的时间复杂度为O(lbn)。但该算法实现比较复杂,并且常系数较大,提出了基于Bit Indexed Tree数据结构的算法解决,在同等时间复杂度的前提下,实现简单,隐含的常系数很小。最后进行了实验测试,分析显示该新算法不论在时间上还是空间上都优于现有的算法。展开更多
Based on the content of radioactive elements (U, Th, K) of strata in two drill holes in the Fuzhou basin, and combined with the result of spore_pollen analysis, the relationship between radioactivity and lithology and...Based on the content of radioactive elements (U, Th, K) of strata in two drill holes in the Fuzhou basin, and combined with the result of spore_pollen analysis, the relationship between radioactivity and lithology and deposit environments is discussed and the results show that the content of radioactive substances is related to the granularity and lithology in sediment, and it is higher in argillaceous sediment (e.g. silt and clay), lower in sand sediment and in the middle in gravels between the above two kinds of sediment. The content of radioactive substances is also related to paleoclimate. A warm and humid environment is propitious to the deposition of radioactive substances, while a cool and dry climate is just the reverse.展开更多
Wireless relay and network coding are two critical techniques to increase the reliability and throughput of wireless cooperative communication systems. In this paper, a complex field network coding （CFNC） scheme wit...Wireless relay and network coding are two critical techniques to increase the reliability and throughput of wireless cooperative communication systems. In this paper, a complex field network coding （CFNC） scheme with the K-th best relay selection （KBS） is proposed and investigated, wherein the K-th best relay is selected to forward the multiplexed signal to the destination. First, the upper bound of the symbol error probability （SEP）, the diversity order, and the coding gain are derived for the CFNC scheme with KBS. Then, the coding gain is utilized as the optimized cri- terion to determine the optimal power allocation. It is validated through analysis and simulation that the CFNC scheme with KBS can achieve full diversity only when K=I, while the diversity order decreases with increasing parameter K, and the optimal power allocation can significantly improve the performance of the CFNC scheme with KBS.展开更多
本文讨论了一个数论函数-k次方函数的算术平均值及几何平均值的极限问题,它与k次方函数值的分布密切相关;设n是正整数,ak(n)表示不小于n的最小k次方部分,bk(n)表示不超过n的最大k次方部分.接着定义了数列:Sn=[ak(1)+ak(2)+ak(3)…ak(n)]...本文讨论了一个数论函数-k次方函数的算术平均值及几何平均值的极限问题,它与k次方函数值的分布密切相关;设n是正整数,ak(n)表示不小于n的最小k次方部分,bk(n)表示不超过n的最大k次方部分.接着定义了数列:Sn=[ak(1)+ak(2)+ak(3)…ak(n)]/n=(sum ak(n) from i=1 to n)/n,lk(n)=[bk(1)+bk(2)+bk(3)…bk(n)/n=(sum bk(n) from i=1 to n)/n,kk(n)=((ak(1)+ak(2)+ak(3)…ak(n))1/n] ak(n)))～n/2=〔sum ak(n) from i=1 to n〕 1/n,lk(n)=(bk(1)+bk(2)+bk(3)…bk(n))～n/2〔sum bk(n) from i=1 to n)〕1/n〔主要研究了整数n的最小k次方ak(n)和最大k次方bk(n)部分数列的均值,采用初等及解析的方法,给出了两个有趣的渐近公式,在所得的定理1的基础上,研究了数列:Sk(n)/Ik(n),Kk(n)/Lk(n),(Sk(n)-Ik(n)),(Kk(n)-Lk(n)的敛散性,并给出了相关的极限式和推论.展开更多
对任意给定的正整数k≥2及任意正整数n,定义n的Smarandachek次补数ak(n)为最小的正整数,使得nak(n)为一个完全k次方幂,即ak(n)=min{u:u.n=mk;u,m∈N},其中N为所有正整数之集合.利用解析方法研究了级数sum from n=1 to +∞ 1/(nak(n))s...对任意给定的正整数k≥2及任意正整数n,定义n的Smarandachek次补数ak(n)为最小的正整数,使得nak(n)为一个完全k次方幂,即ak(n)=min{u:u.n=mk;u,m∈N},其中N为所有正整数之集合.利用解析方法研究了级数sum from n=1 to +∞ 1/(nak(n))s的敛散性,并给出一个有趣的恒等式.展开更多
基金part of a key project carried out in 2008-2011 and financially supported by the National Major Special Science and Technology Project (No.2008ZX05004-001)a Major Special Issue of the China National Petroleum Corporation (No. 2008E-0702)
文摘The Liangshan and Qixia formations in the Sichuan Basin of central China were formed in the earlier middle Permian. Based on outcrop observation of the Changjianggou section at Shangsi, Guangyuan region and 3 rd -order sequence division in typical drillings, one-dimensional spectrum analysis has been used to choose the better curve between the natural gamma ray spectrometry log（ln （Th/K）） in Well-Long17 and the gamma ray log（GR） in Well-Wujia1, respectively, for identifying Milankovitch cycles in Sequence PSQ1 which comprises the Liangshan and Qixia formations, and then to identify the variation in the Milankovitch cycle sequences. On this basis, the system tract and 4 th -order sequence interfaces in Sequence PSQ1 were found via two-dimensional spectral analysis and digital filtering. Finally, a high-frequency sequence division program was established. Among these cycles, long eccentricity （413.0 ka） and short eccentricity （123.0 ka） are the most unambiguous, and they are separately the major control factors in forming 4 th -order （parasequence sets） and 5 th -order （parasequences） sequences, with the average thicknesses corresponding to the main cycles being 11.47 m and 3.32 m in Well-Long17, and 14.21 m and 3.79 m in Well-Wujia1, respectively. In other words, the deposition rate in the beach subfacies is faster than that of the inner ramp facies. The ln（Th/K） curve is more sensitive than the GR as the index of relatively ancient water depth in carbonate deposition. One-dimensional spectrum analysis of ln（Th/K） curve could distinguish the Milankovitch cycle sequences that arose from the Precession cycle （20.90 ka）, with a much higher credibility. Sequence PSQ1 in Well-Long17 contains 10 4 th -order sequences, and the growth span of Sequence PSQ1 consisting of the Liangshan and Qixia formations is about 4.13 Ma. The single deposition thickness of the long eccentricity cycle sequence has the characteristics of thinning and then thickening in the two-dimensional spectrum, which could be used to identify the system tract interface of the 3 rd -order sequence. The precession sequence thickness remains stationary. As a result, the early deposition rate in the mid-Permian of the Sichuan basin was very slow, remaining nearly stationary, and this reflects a sustained depositional environment. Whole-rock carbon and oxygen isotope curves could also prove this point. Milankovitch cycle sequence studies provide a basis for paleoenvironmental analysis and, as such, can be used to analyze ancient climate change, calculate deposition rate and deposition time, and carry out fine isochronous stratigraphic correlation.
文摘K-th number query是计算机算法中的一个基础问题,被广泛作为很多算法实现的重要步骤。对该问题进行了深入研究,并找到了单询问渐近时间复杂度最优的算法。目前一般对于多询问的K-th number query问题使用平衡二叉树解决,询问的时间复杂度为O(lbn)。但该算法实现比较复杂,并且常系数较大,提出了基于Bit Indexed Tree数据结构的算法解决,在同等时间复杂度的前提下,实现简单,隐含的常系数很小。最后进行了实验测试,分析显示该新算法不论在时间上还是空间上都优于现有的算法。
基金This project was granted bythe National Developmentand Reform Commission.Item Number:20041138
文摘Based on the content of radioactive elements (U, Th, K) of strata in two drill holes in the Fuzhou basin, and combined with the result of spore_pollen analysis, the relationship between radioactivity and lithology and deposit environments is discussed and the results show that the content of radioactive substances is related to the granularity and lithology in sediment, and it is higher in argillaceous sediment (e.g. silt and clay), lower in sand sediment and in the middle in gravels between the above two kinds of sediment. The content of radioactive substances is also related to paleoclimate. A warm and humid environment is propitious to the deposition of radioactive substances, while a cool and dry climate is just the reverse.
基金supported by the Major State Basic Research Development Program of China(973 Program No.2012CB316100)the National Natural Science Foundation of China(Nos.61032002/61271246)the 111 Project(No.111-2-14)
文摘Wireless relay and network coding are two critical techniques to increase the reliability and throughput of wireless cooperative communication systems. In this paper, a complex field network coding （CFNC） scheme with the K-th best relay selection （KBS） is proposed and investigated, wherein the K-th best relay is selected to forward the multiplexed signal to the destination. First, the upper bound of the symbol error probability （SEP）, the diversity order, and the coding gain are derived for the CFNC scheme with KBS. Then, the coding gain is utilized as the optimized cri- terion to determine the optimal power allocation. It is validated through analysis and simulation that the CFNC scheme with KBS can achieve full diversity only when K=I, while the diversity order decreases with increasing parameter K, and the optimal power allocation can significantly improve the performance of the CFNC scheme with KBS.
文摘本文讨论了一个数论函数-k次方函数的算术平均值及几何平均值的极限问题,它与k次方函数值的分布密切相关;设n是正整数,ak(n)表示不小于n的最小k次方部分,bk(n)表示不超过n的最大k次方部分.接着定义了数列:Sn=[ak(1)+ak(2)+ak(3)…ak(n)]/n=(sum ak(n) from i=1 to n)/n,lk(n)=[bk(1)+bk(2)+bk(3)…bk(n)/n=(sum bk(n) from i=1 to n)/n,kk(n)=((ak(1)+ak(2)+ak(3)…ak(n))1/n] ak(n)))～n/2=〔sum ak(n) from i=1 to n〕 1/n,lk(n)=(bk(1)+bk(2)+bk(3)…bk(n))～n/2〔sum bk(n) from i=1 to n)〕1/n〔主要研究了整数n的最小k次方ak(n)和最大k次方bk(n)部分数列的均值,采用初等及解析的方法,给出了两个有趣的渐近公式,在所得的定理1的基础上,研究了数列:Sk(n)/Ik(n),Kk(n)/Lk(n),(Sk(n)-Ik(n)),(Kk(n)-Lk(n)的敛散性,并给出了相关的极限式和推论.
文摘对任意给定的正整数k≥2及任意正整数n,定义n的Smarandachek次补数ak(n)为最小的正整数,使得nak(n)为一个完全k次方幂,即ak(n)=min{u:u.n=mk;u,m∈N},其中N为所有正整数之集合.利用解析方法研究了级数sum from n=1 to +∞ 1/(nak(n))s的敛散性,并给出一个有趣的恒等式.
