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Second variation.of harmonic maps between Finsler manifolds

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Science China Mathematics 2004年第1期47卷 39-51页

作者： SHEN Yibing ZHANG Yan Department of Mathematics Zhejiang University Hangzhou 310028 China Department of Mathematics Zhejiang University Hangzhou 310028 China

The first and second variation.formulas of the energy functional for a nondegenerate map between Finsler manifolds is derived. As an application, some nonexistence theorems of nonconstant stable harmonic maps from a F... 详细信息

关键词： Finsler manifold, harmonic map, second variation.

Interannual variation. of bomb radiocarbon during 1977—1998 recorded in coral from Daya Bay, South China Sea

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Science China Earth Sciences 2003年第10期46卷 1040-1048页

作者：沈承德余克服孙彦敏易惟熙杨英周斌 Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China Institute of Earth Environment Chinese Academy of Sciences Xian 710054 China South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China

annual layered samples of coral from 1977 to 1998 were collected from Daya Bay, South China Sea, their bomb-14C (nuclear weapons testing 14C) concentrations were determined and studied, and the atmosphere-sea exchange rate and diffusion thickness were estimated and found to be 17 mol·m-2·a-1 and 32 mm, respectively. The interannual variation.of coral D14C is mainly controlled by oceanic factors. In ENSO years, the coastwise upwelling current of South China Sea gets intensified, hence the coral D14C displays its bottom value. The coral D14C does not respond vividly to the variation.of the solar radiation energy. In the past 20 years or so, the general situation and the oceanic thermal structure of South China Sea are still stable even though inter-annual variation.occurs in the atmosphere-sea interaction and the upwelling current driven by the tropical energy.

关键词： coral, bomb-14C, interannual variation.

variation.in the Coat Protein Gene of Papaya ringspot Virus Isolates from Multiple Locations of China

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Journal of Integrative Plant Biology 2007年第7期49卷 1062-1069页

作者： Jun-Ya Wei De-Bing Liu Xiao-Ying Li Peng Zhou State Key Laboratory for Tropical Crops Biotechnology Institute of Tropical Biology Science China Academy of Tropical Agricultural Science Haikou 571101 China Department of Horticulture South China University of Tropical Agriculture Danzhou 571737 China

The potyvirus Papaya ringspot virus （PRSV） is an important pathogen of papaya that causes severe losses in economic crops for papaya production globally. The coat protein （CP） genes of five PRSV isolates originating from different locations in China were cloned and sequenced. The CP-coding region varied in size from 864-873 nucleotides, encoding proteins of 288-291 amino acids. The five Chinese isolates of PRSV have been characterized as papaya-infecting （PRSV-P）. The CP sequences of the Chinese isolates were compared with those of previously published PRSV isolates originating from different countries at amino acid levels. A number of KE repeat boxes in the N terminus of the PRSV-CP were found in all Chinese isolates. The phylogenetic branching pattern revealed that there was certain extended grouping between geographic locations, and the Asian type probably represents the oldest population of PRSV. The information of CP genes will be useful in designing and developing durable virus resistant-PRSV transgenic papaya in China. Meanwhile broad-spectrum-virus resistant, strongly resistant-PRSV and good safe papaya lines are required.

关键词： coat protein gene Papaya ringspot virus isolates sequence analysis variation.

A new pollen record of the last 2.8 Ma from the Co Ngoin,central Tibetan Plateau

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Science China Earth Sciences 2001年第S1期44卷 292-300页

作者：吕厚远王苏民吴乃琴童国榜羊向东沈才明李世杰朱立平旺罗 Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China anjing Institute of Limnology and Geography Chinese Academy of Sciences Nanjing China Institute of Hydrology and Geology Chinese Academy of Geological Sciences Zhengding China Department of Geography and Anthropology Louisiana State University Baton Rouge USA Institute of Geography Chinese Academy of Sciences Beijing China

A new pollen record from the lake of Co Ngoin in the central Tibetan Plateau provides information on the vegetation and climate changes during the last 2.8 Ma. Seven major significant changes in pollen associations indicate the processes of vegetation change and possible tectonic uplifts. The seven changes in vegetation succession include a temperate montane conifer and broad-leaved mixed forest, cold temperate montane dark conifer forest, alpine shrub-meadow and alpine desert, montane dark coniferous forest and alpine shrub meadow, montane dark coniferous forest and alpine shrub meadow, montane dark coniferous forest and alpine meadow, and alpine desert and meadow. The pollen record provides the evidence of at least five times tectonic uplifts occurring at about 2.58 Ma, 1.87 Ma, 1.17 Ma, 0.83 Ma, and 0.3 Ma ago, respectively. Before 0.8 Ma, this region maintained the altitude below 4000 m a.s.l. Larger amplitude of uplift occurring at about 0.8 Ma ago enforced the plateau rising into cryosphere, shaping the basic topographic pattern of modern plateau. The major successions in vegetation of this area were largely controlled by stepwise uplift of the Tibetan Plateau.

关键词： Tibetan Plateau pollen record vegetation variation.

The secular variation.of inner zone high energy proton environment in the SAA

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Science China Earth Sciences 2005年第12期48卷 2123-2130页

作者： XIE Lun PU Zuyin JIAO Weixin FU suiyan Department of Geophysics Peking University Beijing 100871 China Department of Geophysics Peking University Beijing 100871 China Department of Geophysics Peking University Beijing 100871 China Department of Geophysics Peking University Beijing 100871 China

A long-term variation.of the inner zone high-energy proton environment at low orbits was investigated by DSTM using the adiabatic approximation of charge particle motion with NASA standard radiation models as reference states. The DST results show that over the past three decades the fluxes of high-energy protons at ～1000 km in the South Atlantic Anomaly (SAA) noticeably increased, the center region of proton SAA apparently moved westward and expanded. Calculations of the L-shell averaged lifetime of high-energy protons indicate that the DST pro-vides a reasonable means for estimation of the secular variation.of inner zone proton environ-ment.

关键词： DSTM, radiation belt, SAA, drift shell, secular variation.

Anomalous sound propagation due to the horizontal variation.of seabed acoustic properties

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Science China(Physics,Mechanics & Astronomy) 2004年第5期47卷 571-580页

作者： LI Zhenglin ZHANG Renhe PENG Zhaohui LI Xilu National Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing 100080 China National Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing 100080 China National Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing 100080 China National Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing 100080 China

The sound propagation in shallow water is greatly influenced by the acoustic properties of seabed. An anomalous transmission loss was observed in an experiment, and a range dependent bottom model with horizontal variation.of seabed acoustic property is proposed and could be well used to explain the anomalous phenomena. It is shown that the horizontal variation.of bottom properties has a great effect on underwater sound propagation, and it should be given much attention in sound propagation and geoacoustic inversion problems.

关键词： sound propagation, bottom acoustic property, horizontal variation.

Genome organization and variation.in the 3’-partial sequence of garlic latent virus in China

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Science China(Life Sciences) 2002年第4期45卷 441-448页

作者：陈炯郑红英陈剑平杨崇良 College of Life Sciences Zhejiang University Hangzhou 310029 China Virology Department Zhejiang Academy of Agricultural Sciences Hangzhou 310021 China

Ten different isolates of a carlavirus were detected by degenerate PCR from 12 garlic samples collected from 6 provinces in China, and the complete genome sequence of the Zhejiang isolate ZJ1 and 3′-terminal sequences of 9 other isolates were determined. The RNA genome of isolate ZJ1 consisted of 8363nts excluding the 3′-poly (A) tail, and the genome organization was similar to other carlaviruses with 6 open reading frames encoding a replicase, TGB1, TGB2, TGB3, CP and NABP respectively. Sequence comparisons showed that all 10 isolates were Garlic latent virus (GarLV). The variation. in the TGB2, TGB3 and NABP were more significant than those in the CP. High homology was also detected between those isolates and Shallot latent virus (ShLV). Phylogenetic analysis suggested that GarLV isolates from garlic can be divided into 4 main groups and Chinese isolates belonged to each group. This is the first reported molecular analysis of members of the genus Carlavirus in China.

关键词： garlic latent virus, nucleotide sequence, genome organization, variation.

Regional tectonic deformation setting before the Ms8.1 earthquake in the west of the Kunlun Mountains Pass

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Science China Earth Sciences 2003年第Z2期46卷 227-242页

作者： JIANG Zaisen (江在森) ZHANG Xi (张希) ZHU Yiqing (祝意青) ZHANG Xiaoliang (张晓亮) WANG Shuangxu (王双绪) Center for Analysis and Prediction China Seismological Bureau Beijing 100036 China The Second Center for Crustal Deformation Monitoring China Seismological Bureau Xi'an 710054 China The Second Center for Crustal Deformation Monitoring China Seismological Bureau Xi'an 710054 China The Second Center for Crustal Deformation Monitoring China Seismological Bureau Xi'an 710054 China The Second Center for Crustal Deformation Monitoring China Seismological Bureau Xi'an 710054 China

This paper gives a preliminarily study of the regional tectonic deformation setting before the Ms8.1 earthquake that occurred in the west of the Kunlun Mountains Pass; in the study, the data of the velocity field of crustal horizontal movement during 1991-2000 observed by GPS in and around the Qinghai-Tibet block and those of gravity reiteration in 1998 and 2000 were used. Analysis shows that the preparation and occurrence of this large earthquake are related to the horizontal movement and deformation setting in a large region and might be attributed to the block activity on a relatively large scale. Within the Qinghai-Tibet block, the region of left-lateral shear deformation is of a very large extent. This large earthquake occurred right in such a place where the left-lateral shear strain along the fault strike had the highest rate and the planar dilatation strain was tensile, which was on the margin of negative value region of abnormal gravity variation. The regional tectonic deformation setting can help the huge left-lateral strike-slip rupture to develop.

关键词： earthquake in the west of the Kunlun Mountains Pass, regional horizontal movement, tectonic deformation, gravity variation.

NOC model of the earth's main magnetic field

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Science China Earth Sciences 2003年第9期46卷 882-894页

作者：徐文耀 Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100101 China

The method of natural orthogonal components (NOC) is used to analyze the earth抯 main magnetic field IGRF 1900—2000, and the NOC model of the field is established. The first step of the analysis is to calculate eigen modes of the field from the Gauss coefficients of IGRF 1900—2000. Then the magnetic field for each epoch is expanded in a series at the basic function set constructed by the eigen modes, and the intensity coefficients of the eigen modes are calculated. Test of the convergency and stability of the NOC model shows that the model has very short series and much rapid convergency in comparison with the conventional spherical harmonic models of IGRF. Comparison of the eigen modes obtained from different IGRF model groups indicates that the low-degree eigen modes are rather stable, while the high-degree modes show a relatively large variability. The physical meaning of the eigen modes in the NOC model is discussed, and an interesting relationship is found between the spatial structure of the main field and its secular variation.

关键词： main magnetic field, IGRF, spherical harmonic series, natural orthogonal components (NOC), secular variation.