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Gamma—Ray Pulsars Expected in the Outer Gap Model of Gamma—Ray Emission

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chinese Physics Letters 2003年第3期20卷 433-435页

作者：张力吴杰等 NationalAstronomicalObservatoriesandYunnanObservatory ChineseAcademyofSciencesPOBox110Kumming650010 DepartmentofPhysics YunnanUniversityKunming650091

We study the possibility of high-energy gamma-ray emission from the known 1130 radio pulsars based on the outer gap model of high energy emission from pulsars. We estimate the fractional size of outer gap, the integrated flux, the gamma-ray luminosity for each known radio pulsar, and find that only 14% of the known radio pulsars are gamma-ray emitters according to the outer gap model. In the sample of possible 156 gamma-ray pulsars, our statistical analysis indicates that the distributions of the spin-down powers and the ages of these pulsars concentrate mainly on 1033.5-1039 erg/s and 103-107 y, respectively. The predictions of gamma-ray pulsars detected by the AGILE and GLAST missions are given.

关键词： Pulsars

Two personification strategies for solving circles packing problem

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Science China(Technological Sciences) 1999年第6期42卷 595-602页

作者：黄文奇许如初 College of Computer Science Huazhong University of Science and Technology Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100080 China

Two personification strategies are presented, which yield a highly efficient and practical algorithm for solving one of the NP hard problems——circles packing problem on the basis of the quasi-physical algorithm. A very clever polynomial time complexity degree approximate algorithm for solving this problem has been reported by Dorit *** and Wolfgang Maass in J. ACM. Their algorithm is extremely thorough-going and of great theoretical significance. But, just as they pointed out, their algorithm is feasible only in conception and even for examples frequently encountered in everyday life and of small scale, it is the case more often than not that up to a million years would be needed to perform calculations with this algorithm. It is suggested toward the end of their paper that a heuristic algorithm of higher practical effectiveness should be sought out. A direct response to their suggestion is intented to provide.

关键词： packing problem NP hard heuristic algorithm personification method quasi-physical method.

Effects of vegetation coverage and seasonal change on soil microbial biomass and community structure in the dry-hot valley region

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Journal of Mountain Science 2018年第7期15卷 1546-1558页

作者： WU Han XIONG Dong-hong XIAO Liang ZHANG Su YUAN Yong SU Zheng-an ZHANG Bao-jun YANG Dan Key Laboratory of Mountain Hazards and Earth Surface Processes Institute of Mountain Hazards and Environment Chinese Academy of Science Chengdu 610041 China University of chinese Academy of Sciences Beijing 100049 China

Soil microorganisms are sensitive indicator of soil health and quality. Understanding the effects of vegetation biomass and seasonal change on soil microorganisms is vital to evaluate the soil quality and implement vegetation restoration. This study analyzed the soil phospholipid fatty acids(PLFAs) in fresh and withered Kudzu(Pueraria montana var. lobata) vegetation conditions in different seasons. The results showed that vegetation biomass and seasonal change significantly affected microbial biomass and its community structure. Both fresh and withered Kudzu cover significantly increased soil microbial biomass, and the growth effect of microbes in the soil with fresh Kudzu cover was more obvious than that with withered Kudzu cover. Compared with the dry season, the rainy season significantly increased the microbial biomass and the B/F(the ratio of bacterial to fungal PLFAs) ratio but dramatically reduced the G+/G-(the ratio of gram-positive to gram-negative bacteria PLFAs). Kudzu cover and seasonal change had a significant effect on microbial structure in soil covered by higher vegetation biomass. Furthermore, soil temperature and moisture had different correlations with specific microbial biomass in the two seasons. Our findings highlight the effect of Kudzu vine cover on the soil microenvironment and soil microhabitat, enhancing the soil quality in the Dry-hot Valley of Jinsha River, Southwest China.

关键词： Phospholipid fatty acid Vegetation Soil microbes Soil temperature Soil moisture Dry-hot valley

Using two contrasting methods with the same tracers to trace the main sediment source in a mountainous catchment

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Journal of Mountain Science 2019年第10期16卷 2257-2270页

作者： WU Han XIONG Dong-hong ZHANG Su YUAN Yong LI Wan-Xin LIU Lin SU Zheng-an LU Xiao-ning Key Laboratory of Mountain Hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of ScienceChengdu610041China Chengdu University of Information Technology Chengdu610225China University of chinese Academy of Sciences Beijing100049China

Assessing the contribution of sediments from different sources is essential to understand erosive processes and formulate further soil conservation strategies to address environmental *** this study,we combined the source fingerprinting approach with geochemistry,including comparison of potential sources,and distribution pattern of major elements,to estimate the different land-use relative contributions to streambed sediment in the Luowugou catchment(13.5 km^2)located on the Heishui River,the first branch of the Jinsha River,China.A total of 57 samples from stream bank,cropland,grassland,forest land,and sediments were collected,and then,15 elements were analyzed foreach *** fingerprinting results demonstrated that the stream bank(62.4%)had the greatest relative contribution to the bed sediment yield,while cropland,grassland,and forest land contributed 18.6%,14.9%,and 4.1%to the bed sediments,*** comparison to the fingerprinting method,even though the results upon geochemistry only provide a qualitative assessment,the ranking of sediment contributions based on geochemistry was consistent with the sediment fingerprinting ranking,that is,stream bank>cropland>grassland>forest *** findings suggest that the focal point for sediment control practices should be the stream bank rather than cropland in the *** can result in an important means in validating the fingerprinting results.

关键词： Soil erosion Sediment tracing Geochemistry Stream bank Jinsha River

Mineral inclusions in zircon domains and geological significance of SHRIMP U-Pb dating for coesite-bearing zircons of paragneiss in Sulu terrane, eastern China

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Science China Earth Sciences 2005年第2期48卷 175-184页

作者： LIU Fulai YANG Jingsui XU Zhiqin Institute of Geology Chinese Academy of Geological SciencesBeijing100037China Institute of GeologyChinese Academy of Geological SciencesBeijing100037China Institute of GeologyChinese Academy of Geological SciencesBeijing100037China

Laser Raman spectroscopy and cathodoluminescence (CL) image reveal that zircons separated from paragneisses in the southwestern Sulu terrane (eastern China) preserve multi-stage mineral assemblages in different zircon domains. In the same paragneiss zircon sample, some zircon grains retain inherited (detrital) cores with abundant low-pressure mineral inclusions of Qtz + Phe + Ap + impurities and Qtz + Phe + impurities. The ultrahigh-pressure (UHP) metamorphic overgrowths mantles of these zircons preserve Coe, Coe + Phe and other UHP mineral inclusions, indicating that these inherited (detrital) zircons from protoliths experienced metamorphic recrystallization during the Sulu UHP metamorphic event. However, other zircon grains preserve UHP mineral inclusions of Coe, Coe + Ap and Coe + Phe in the cores and mantles, whereas the outmost rims contain quartz (Qtz) and other low-pressure mineral inclusions. These phenomena prove that the second group zircons were crystallized at UHP metamorphic stage and overprinted by the late retrogressive metamorphism related to the Sulu terrane exhumation. SHRIMP U-Pb dating reveals that zircons separated from the paragneisses recorded complicated geochronological traces. Some zircons retain inherited cores with the 206Pb/238U ages of 284-754 Ma, indicating the complexity of the detrital zircons in protoliths. Coesite-bearing zircon domains recorded 238-266 Ma (with the average age of 245(14 Ma) for the UHP metamorphic event. The retrogressive rims of zircons recorded 213-223 Ma (with the average age of 217(15 Ma) for the late-stage amphibolite facies metamorphic event, indicating that the rapid exhumation time for the Sulu UHP terrane is about 220 Ma.

关键词： Sulu terrane, paragneiss, zircon, mineral inclusion, cathodoluminescence, SHRIMP U-Pb dating.

Impact of permafrost change on the Qinghai-Tibet Railroad engineering

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Science China Earth Sciences 2004年第z1期47卷 122-130页

作者： WU Qingbai CHENG Guodong MA Wei State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research Institute Chine Academy of Sciences Lanzhou 730000 China

Permafrost along the Qinghai-Tibet Railroad produces the great change under the influence of climate change, such as the decreasing of permafrost table, the rising of permafrost temperatures, etc. Climate effect on permafrost is the long-term process. Engineering action makes rapidly permafrost the large extent change. On the basis of analyzing the permafrost change under the climate change and engineering action, the thermal regime and spatial distribution of permafrost are predicted for air temperature rising 1℃ and 2℃ after 50 years in this paper. The results show that climate change results in the larger change for the thermal regime and spatial distribution of permafrost. Permafrost change will produce the great effect on the Qinghai-Tibet Railroad engineering, not only resulting in the decreasing of permafrost table beneath the roadbed, but also resulting in thawing settlement due to the thawing of ground ice near permafrost table. The idea of cooling roadbed and active protecting permafrost for the Qinghai-Tibet Railroad engineering could adjust and control the permafrost thermal state, some better methods are provided to ensure the engineering stability in the areas of warm permafrost and high ice content.

关键词： permafrost climate change Qinghai-Tibet Railroad roadbed stability.

Generation of cell-type-specific gene mutations by expressing the sgRNA of the CRISPR system from the RNA polymerase II promoters

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Protein & Cell 2015年第9期6卷 689-692页

作者： Jiaqiang Wang (1) Xin Li (1) (2) Yanhua Zhao (1) Jingyu Li (1) Qi Zhou (1) (2) Zhonghua Liu (1) 1.College of Life Sciences Northeast Agricultural University Harbin 150030 China 2.State Key Laboratory of Reproductive Biology Institute of Zoology Chinese Academy of Sciences Beijing 100101 China

Recently, the CRISPR/Cas9 system is emerging as a powerful tool for genome editing （Chang et al., 2013; Li et al., 2013; Niu et al., 2014; Shen et al., 2013; Wan et al., 2015; Wang et al., 2013） and genetic screening （Konermann et al., 2015）, and holds great promise for biomedical applications in disease modeling and gene therapy by in vivo genome editing （Mad- dalo et al., 2014; Xue et al., 2014）.

关键词： Sanger Sequencing Genome Editing Gene Editing CRISPR System Produce Gene Mutation

Hierarchical Co3O4 porous nanowires as an efficient bifunctional cathode catalyst for long life Li-O2 batteries

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Nano Research 2015年第2期8卷 576-583页

作者： Qingchao Liu Yinshan Jiang Jijing Xu Dan Xu Zhiwen Chang Yanbin Yin Wanqiang Liu Xinbo Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China School of Materials Science and Engineering Jilin University Changchun 130012 China Graduate University of chinese Academy of Sciences Beijing 100049 China School of Materials Science and Engineering Changchun University of Science and Technology Changchun 130022 China

Hierarchical Co3O4 porous nanowires （NWs） have been synthesized using a hydrothermal method followed by calcination. When employed as a cathode catalyst in non-aqueous Li-oxygen batteries, the Co3O4 NWs effectively improve both the round-trip efficiency and cycling stability, which can be attributed to the high catalytic activities of Co3O4 NWs for the oxygen reduction reaction and the oxygen evolution reaction during discharge and charge processes, respectively.

关键词： lithium-oxygen batteries bifunctional cathodecatalyst Co304 nanowires cycling stability

Coupling virio-and bacterioplankton populations with environmental variable changes in the Bohai Sea

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Acta Oceanologica Sinica 2020年第6期39卷 72-83页

作者： Caixia Wang Lin Wu Yibo Wang James S.Paterson James G.Mitchell Xiaoke Hu Key Laboratory of Coastal Biology and Bioresource Utilization Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China Laboratory for Marine Biology and Biotechnology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China University of chinese Academy of Sciences Beijing 100049China Ocean School Yantai UniversityYantai 264003China College of Science and Engineering Flinders UniversityAdelaideSA 5001Australia

Uncovering the role of environmental factors and finding critical factors which harbor significant fractions in governing microbial communities remain key questions in coastal marine *** detect the interactions between environmental factors and distributions of virio-and bacterioplankton in trophic coastal areas,we used flow cytometry to investigate the abundance of virio-and bacterioplankton covering 31 stations in the Bohai Sea of *** results suggested that the average abundance of total virus(TV)in winter(~2.29×108 particles/mL)was slightly lower than in summer(~3.83×108 particles/mL).The mean total bacterial abundance(TB)was much lower in winter(~2.54×107 particles/mL)than in summer(~5.43×107 particles/mL).Correlation analysis via redundancy analysis(RDA)and network analysis among virioplankton,bacterioplankton and environmental factors revealed that the abundances of viral and bacterial subpopulations depend on environmental *** winter,only temperature significantly influenced the abundances of virio-and *** summer,in addition to temperature,both salinity and nutrient(SiO2)had a remarkable impact on the distribution of virioand *** results showed a clear seasonal and trophic pattern throughout the whole water system,which revealed that temperature and eutrophication may play crucial roles in microbial distribution pattern.

关键词： virioplankton bacterioplankton flow cytometry network Bohai Sea