A 51.85 m firn core drilled in Princess Elizabeth Land, Antarctica, during the 1996-1997 Chinese First Antarctic Inland Expedition, has been measured for δ 18 O and major ions. Based on the high quality data ...A 51.85 m firn core drilled in Princess Elizabeth Land, Antarctica, during the 1996-1997 Chinese First Antarctic Inland Expedition, has been measured for δ 18 O and major ions. Based on the high quality data of the seasonal variations of major ions, the firn core was dated with errors within ±3 years. The 51.85 m firn core record extends for 251 years (A. D. 1745-1996). The results of the glaciochemistry data of the firn core show that the mean concentrations of Cl -, Na + and Mg 2+ are similar to those reported from other coastal areas in East Antarctica. However, mean concentrations of Ca 2+ are much higher than those reported from other regions, this anomaly phenomenon may be related to the strong local terrestrial sources. It is found that the variations of three kinds of sea salt ions (Cl -, Na + and Mg 2+ ) in the past 150 years show very similarly rising trends, which may be the results the Southern Hemisphere warming in the past century.展开更多
According to the model of Dornyei three levels （language level, learner level, learning situation level） of foreign language learning motivation, the paper mainly discusses ＂course-specific motivational components...According to the model of Dornyei three levels （language level, learner level, learning situation level） of foreign language learning motivation, the paper mainly discusses ＂course-specific motivational components＂ from learning situation level, and puts forward advantages and disadvantages of the model. Basing on the model, the paper further expounds relative contents relating to learner＇s motivation, for example, syllabus, teaching methods and learning tasks. At last, the paper states the existing problems in language teaching and learning, at the same time, pointing out some suggestions.展开更多
基金the Key International Cooperation Project of Ministry of Science and Technology of China,No.2001CB711003the National Natural Science Foundation of China,No.40305007the Science and Technology Innovation Project of Northwest Normal University,No.NWNU-KJCXGC-02-20.
文摘A 51.85 m firn core drilled in Princess Elizabeth Land, Antarctica, during the 1996-1997 Chinese First Antarctic Inland Expedition, has been measured for δ 18 O and major ions. Based on the high quality data of the seasonal variations of major ions, the firn core was dated with errors within ±3 years. The 51.85 m firn core record extends for 251 years (A. D. 1745-1996). The results of the glaciochemistry data of the firn core show that the mean concentrations of Cl -, Na + and Mg 2+ are similar to those reported from other coastal areas in East Antarctica. However, mean concentrations of Ca 2+ are much higher than those reported from other regions, this anomaly phenomenon may be related to the strong local terrestrial sources. It is found that the variations of three kinds of sea salt ions (Cl -, Na + and Mg 2+ ) in the past 150 years show very similarly rising trends, which may be the results the Southern Hemisphere warming in the past century.
文摘According to the model of Dornyei three levels （language level, learner level, learning situation level） of foreign language learning motivation, the paper mainly discusses ＂course-specific motivational components＂ from learning situation level, and puts forward advantages and disadvantages of the model. Basing on the model, the paper further expounds relative contents relating to learner＇s motivation, for example, syllabus, teaching methods and learning tasks. At last, the paper states the existing problems in language teaching and learning, at the same time, pointing out some suggestions.
