Orthogonal projection methods have been widely used to solve linear systems. Little attention has been given to oblique projection methods, but the class of oblique projection methods is particularly attractive for la...Orthogonal projection methods have been widely used to solve linear systems. Little attention has been given to oblique projection methods, but the class of oblique projection methods is particularly attractive for large nonsymmetric systems. The purpose of this paper is to consider a criterion for judging whether a given appro ximation is acceptable and present an algorithm which computes an approximate solution to the linear systems Ax=b such that the normwise backward error meets some optimality condition.展开更多
Continual deep-water sediments from the late Early Devonian to the Late Permian extended in wide areas of western Guangxi. We analyzed the major, trace, and rare earth elements of the Upper Paleozoic cherts in Badu, w...Continual deep-water sediments from the late Early Devonian to the Late Permian extended in wide areas of western Guangxi. We analyzed the major, trace, and rare earth elements of the Upper Paleozoic cherts in Badu, western Guangxi. High non-terrigenous SiO2 contents (Sinon_ter/Sibulk(%)〉 80%) and pure chert components (〉 70%) indicate a large extent of silicifi- cation in the Upper Paleozoic cherts, except for the Upper Devonian-Lower Carboniferous Luzhai Formation cherts, which have lower non-terrigenous SiO2 contents (avg. 71.8%) and pure chert components (40%-70%). The Al/(AI+Fe+Mn) ratios and Feter/Febulk(%) values of samples from the lowest horizon of the Pingen Formation are 0.05-0.26, 13.1%-14.5%, respec- tively, indicating hydrothermal origins. All other samples show high Al/(Al+Fe+Mn) ratios (0.39±0.81) and high Feter/Febulk(%) values (23.1%-186.8%), indicating non-hydrothermal origins. The Pingen Formation and Liujiang Formation cherts show slightly-moderately negative Ce anomalies (0.71±0.07, 0.81±0.08, respectively) and higher Y/Ho ratios (33.49±1.27, 36.10±2.05, respectively) than PAAS. This suggests that these cherts were deposited in the open marine basin, rather than in the intracontinental rift basin as previously assumed. The Luzhai Formation cherts may be deposited near the seamount or sea- floor plateaus with no negative Ce anomalies (1.09±0.07) and no significant Y-Ho fractionation (Y/Ho=28.60±1.25). The Nandan Formation and Sidazhai Formation cherts were deposited in the open-ocean basin with moderately negative Ce anom- alies (0.67±0.08, 0.73±0.11, respectively) and high Y/Ho ratios (36.01±1.00, 32.00±2.25, respectively). On the basis of our studies about cherts, we conclude that the Youjiang Basin originated as part of the Paleo-Tethys that controlled the deposition- al environments of cherts during late Paleozoic. The rift of the Youjiang Basin had occurred at least since the Early-Middle Devonian. The basin had a trend of evolving into an open-ocean basin during the Early-Middle Permian.展开更多
Let (S,≤) be a strictly totally ordered monoid which is also artinian, and R a right noetherian ring. Assume that M is a finitely generated right R-module and N is a left Rmodule. Denote by [[MS,≤]] and [NS,≤] the ...Let (S,≤) be a strictly totally ordered monoid which is also artinian, and R a right noetherian ring. Assume that M is a finitely generated right R-module and N is a left Rmodule. Denote by [[MS,≤]] and [NS,≤] the module of generalized power series over M, and the generalized Macaulay-Northcott module over N, respectively. Then we show that there exists an isomorphism of Abelian groups:Tori[[ RS,≤]]([[MS,≤]],[NS,≤])≌ s∈S ToriR (M,N).展开更多
基金National Natural Science Foundation of China(60474023)Major State Basic Research Development Program ofChina(2002CB312200)China Postdoctoral Science Foundation(20060390033)
文摘Orthogonal projection methods have been widely used to solve linear systems. Little attention has been given to oblique projection methods, but the class of oblique projection methods is particularly attractive for large nonsymmetric systems. The purpose of this paper is to consider a criterion for judging whether a given appro ximation is acceptable and present an algorithm which computes an approximate solution to the linear systems Ax=b such that the normwise backward error meets some optimality condition.
基金supported by National Natural Science Foundation of China(Grant Nos.40972078and40921062)"111Project"(Grant No.B08030)Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)
文摘Continual deep-water sediments from the late Early Devonian to the Late Permian extended in wide areas of western Guangxi. We analyzed the major, trace, and rare earth elements of the Upper Paleozoic cherts in Badu, western Guangxi. High non-terrigenous SiO2 contents (Sinon_ter/Sibulk(%)〉 80%) and pure chert components (〉 70%) indicate a large extent of silicifi- cation in the Upper Paleozoic cherts, except for the Upper Devonian-Lower Carboniferous Luzhai Formation cherts, which have lower non-terrigenous SiO2 contents (avg. 71.8%) and pure chert components (40%-70%). The Al/(AI+Fe+Mn) ratios and Feter/Febulk(%) values of samples from the lowest horizon of the Pingen Formation are 0.05-0.26, 13.1%-14.5%, respec- tively, indicating hydrothermal origins. All other samples show high Al/(Al+Fe+Mn) ratios (0.39±0.81) and high Feter/Febulk(%) values (23.1%-186.8%), indicating non-hydrothermal origins. The Pingen Formation and Liujiang Formation cherts show slightly-moderately negative Ce anomalies (0.71±0.07, 0.81±0.08, respectively) and higher Y/Ho ratios (33.49±1.27, 36.10±2.05, respectively) than PAAS. This suggests that these cherts were deposited in the open marine basin, rather than in the intracontinental rift basin as previously assumed. The Luzhai Formation cherts may be deposited near the seamount or sea- floor plateaus with no negative Ce anomalies (1.09±0.07) and no significant Y-Ho fractionation (Y/Ho=28.60±1.25). The Nandan Formation and Sidazhai Formation cherts were deposited in the open-ocean basin with moderately negative Ce anom- alies (0.67±0.08, 0.73±0.11, respectively) and high Y/Ho ratios (36.01±1.00, 32.00±2.25, respectively). On the basis of our studies about cherts, we conclude that the Youjiang Basin originated as part of the Paleo-Tethys that controlled the deposition- al environments of cherts during late Paleozoic. The rift of the Youjiang Basin had occurred at least since the Early-Middle Devonian. The basin had a trend of evolving into an open-ocean basin during the Early-Middle Permian.
基金the National Natural Science Foundation of China (No.10961021)the Teaching and Research Award Program for Outsanding Young Teachers in Higher Education Institutions of Ministry of Education(No.NCET-02-080)
文摘Let (S,≤) be a strictly totally ordered monoid which is also artinian, and R a right noetherian ring. Assume that M is a finitely generated right R-module and N is a left Rmodule. Denote by [[MS,≤]] and [NS,≤] the module of generalized power series over M, and the generalized Macaulay-Northcott module over N, respectively. Then we show that there exists an isomorphism of Abelian groups:Tori[[ RS,≤]]([[MS,≤]],[NS,≤])≌ s∈S ToriR (M,N).