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The Dimension Vectors of Indecomposable Modules of Cluster-tilted Algebras and the Fomin-Zelevinsky Denominators Conjecture

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Acta Mathematica Sinica,English Series 2012年第3期28卷 581-586页

作者： Shengfei GENG Liangang PENG Department of Mathematics Sichuan University

The main result of this paper is that any two non-isomorphic indecomposable modules of a cluster-tilted algebra of finite representation type have different dimension vectors. As an application to cluster algebras of Types A, D, E, we give a proof of the Fomin Zelevinsky denominators conjecture for cluster variables, namely, different cluster variables have different denominators with respect to any given cluster.

关键词： Dimension vector cluster tilting object cluster-tilted algebra denominator

Minimum amount of extracting solvent of AB/BC countercurrent extraction separation using organic feed

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Journal of Rare Earths 2014年第5期32卷 439-444页

作者：程福祥吴声张玻刘艳王嵩龄廖春生严纯华 China Minmetals (Beijing) Research Institute of RE Co. Ltd Beijing national Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications PKU-HKU Joint Lab on Rare Earth Materials and Bioinorganic Chemistry Peking University

For an AB/BC countercurrent extraction separation using organic feed, the conditions to have minimum amount of ex- tracting solvent （Smin） and minimum amount of scrubbing agent solution （Wmin） were discussed, and the formulae of both Sroin and Wmin were deduced. It was shown that only when the ratio of flowrate of central component B leaving aqueous outlet to that leaving organic outlet took a certain optimal value, the AB/BC separation could have Smin as well as Wmin, and this optimal ratio was decided by the separation factors between the three components but independent of feed composition. Smin was only relative to the separation factor of A/C pair but regardless of the separation factors of other pairs as well as feed composition, whereas Wmin was determined by the separation factors between the components together with feed composition. Meanwhile it was also found that the organic stream out of feed stage was same composition as the initial organic feed when the separation system was given by the two minimum amounts and its steady state was achieved. Finally the results above were used to design a LuYb/YbTm separation case and the stage-wise compositions of each component in both the organic and the aqueous phase at steady state were given by computer simulation.

关键词： rare earths countercurrent extraction hyperlink process 3-component separation

Catalytic performance of Fe modified K/Mo_2C catalyst for CO hydrogenation

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Journal of Natural Gas Chemistry 2011年第5期20卷 520-524页

作者： Minglin Xiang Dudu Wu Juan Zou Debao Li Yuhan Sun Xichun She Hunan Changling Petrochemical S＆T Developing Co. Ltd. Yueyang 414012 Hunan China School of Pharmacy Guangdong Medical College Dongguan 523808 Guangdong China State Key Laboratory of Coal Conversion Shanxi Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 Shanxi China

Fe modified and un-modified K/Mo2C were prepared and investigated as catalysts for CO hydrogenation reaction. Compared with K/Mo2C catalyst, the addition of Fe increased the production of alcohols, especially the C2＋OH. Meanwhile, considerable amounts of C5＋ hydrocar- bons and C2= -C4= were formed, whereas methane selectivity greatly decreased. Also, the activity and selectivity of the catalyst were readily affected by the reaction pressure and temperature employed. According to the XPS results, Mo4＋ might be responsible for the production of alcohols, whereas the low valence state of Mo species such as Mo^0 and/or Mo^2＋ might be account for the high activity and selectivity toward hydrocarbons.

关键词： K/Mo2C Fe promoter CO hydrogenation

High temperature determines the ups and downs of small brown planthopper Laodelphax striatellus population

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Insect Science 2013年第3期20卷 385-392页

作者： Xiang-Dong Liu Ai-Min Zhang Department of Entomology Nanjing Agricultural University Nanjing China

Small brown planthopper, Laodelphax striatellus （Fall6n） numbers usually drop sharply in the summer and revive quickly in the autumn. However, it is unclear whether and how the high temperature plays a role in this process. The effects of durations of heat exposure （33~C） on life-history traits were examined here. Exposure of adults for 1 day during the oviposition stage led to a very low survival of nymphs. The average longevity ofL. striatellus exposed for 1-31 days from oviposition was significantly longer than that of the control （27℃）. Short-term （1-5 days） heat exposure of the third instar nymphs did not significantly influence eclosion, but exposure of the fourth instar nymphs significantly increased eclosion. Lifespan from egg to adult was significantly lengthened when the third instar nymphs were exposed to heat for 2-15 days, or the fourth instar were exposed for 10 days. The preoviposition period was prolonged by heat exposure of the third or fourth instar nymphs. Short-term heat exposure of less than 3 days of the third or fourth instar nymphs did not restrict fecundity, but when the exposure duration exceeded 5 days the total eggs per female and hatchability decreased. Exposure to high temperature increased the brachypter rate of adults. In summary, low survival and slowing development under heat exposure resulted in population decline in the summer, and the relatively high fecundity and brachypter rate led to quick revival in autumn. Temperature in the summer determines the rise and fall in numbers ofL. striatellus.

关键词： development fecundity heat exposure Laodelphax striatellus wing form

Energetic Laser-Ion Acceleration by Strong Charge-Separation Field

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Plasma Science and Technology 2010年第3期12卷 268-276页

作者：黄永盛王乃彦施义晋汤秀章毕远杰高喆 China Institute of Atomic Energy Department of Engineering Physics Tsinghua University

The laser-ion acceleration from the ultra-short and ultra-intense laser-matter interactions attracts more and more interest nowadays. When a laser pulse interacts with a target, relativistic electrons are generated in a period of few femtoseconds and driven away by the ponderomotive force, then a huge charge-separation field forms. In general cases, the ion acceleration is determined by this charge-separation field and the scale length of the plasma density. A general time-dependent solution is obtained to describe laser-plasma isothermal expansions into a vacuum, which is the fundamental theory of the laser-ion acceleration. It is adequate for non-quasi-neutral plasmas and different types of the scale length of the density gradient. The previous solutions are some special cases of our general solution. It is found that there exist both a compression layer of the ion velocity distribution and a potential well for sorue initial conditions. However, many unaccounted idiographic solutions, which may be used to reveal new mechanisms of ion acceleration, may be deduced from our general solutions.

关键词： laser-ion acceleration ultra-short and ultra intense charge separation field compression layer potential well

Fluid Geochemical Features and Preservation Conditions of Marine Stratum in Typical Structure of Jianghan Plain Area

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Journal of Earth Science 2011年第6期22卷 768-779页

作者：徐国盛龚德瑜袁海锋李昌鸿王国芝胡晓凤林娟华朱建敏 State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of Technology Institute of Exploration and Exploitation Jianghan Oil Field Branch of SINOPEC

Many scholars carried out large quantity of researches on oil and gas preservative condi-tions of marine carbonate rocks from the aspects of cap rocks,faults,formation water,hydrodynamic,and *** article gives dynamic evaluation on oil and gas preservative conditions of marine stratum in Jianghan（江汉） plain of multiphase tectonic disturbance from the view of paleofluid *** conclusion shows that there mainly existed fluid filling of two periods in the reservoir of Lower-Middle Triassic to *** fluid filled in the earlier period came from Lower *** interchange of fluid in Lower-Middle Triassic to Permian suggested the oil and gas in Lower Pa-laeozoic had been broken *** fluid filled in the later period（Lower-Middle Triassic to Permian） came from the same or adjacent strata and lacked anatectic fluidogenous features coming from *** good preservative conditions of bulk fluid at the time,the fluid of Lower-Middle Triassic to Permian and that of Lower Palaeozoic did not connect with each ***,the hydrocarbon generation peak of marine source rocks had passed or the paleo-oil and gas reser-voirs had been destroyed at that time and the marine stratum of Palaeozoic to Triassic in the research area did not put out commercial oil and gas flow.

关键词： fluid geochemistry preservative condition of oil and gas marine stratum Jiang-han plain.

Carbon dioxide reforming of methane over Ni/Mo/SBA-15-La_2O_3 catalyst:Its characterization and catalytic performance

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Journal of Natural Gas Chemistry 2011年第5期20卷 465-470页

作者： Jian Huang Renxiong Ma Tao Huang Anrong Zhang Wei Huang Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province Taiyuan University of Technology Taiyuan 030024 Shanxi China Institute of Engineering Thermophysics ＆ Chinese Academy of Sciences Beijing 100190 China Department of Applied Chemistry Yuncheng University Yuncheng 044000 Shanxi China

The Ni/Mo/SBA-15 catalyst was modified by La2O3 in order to improve its thermal stability and carbon deposition resistance during the CO2 reforming of methane to syngas. The catalytic performance, thermal stability, structure, dispersion of nickel and carbon deposition of the modified and unmodified catalysts were comparatively investigated by many characterization techniques such as N2 adsorption, H2-TPR, CO2-TPD, XRD, FT-IR and SEM. It was found that the major role of La2O3 additive was to improve the pore structure and inhibit carbon deposition on the catalyst surface. The La2O3 modified Ni/Mo/SBA-15 catalyst possessed a mesoporous structure and high surface area. The high surface area of the La2O3 modified catalysts resulted in strong interaction between Ni and Mo-La, which improved the dispersion of Ni, and retarded the sintering of Ni during the CO2 reforming process. The reaction evaluation results also showed that the La2O3 modified Ni/Mo/SBA-15 catalysts exhibited high stability.

关键词： CO2-reforming SBA-15 molecular sieve carbon deposition La-promoted

A New Perspective on Understanding the Reduced Spring Dust Storm Frequency in Inner Mongolia, China

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International Journal of Disaster Risk Science 2015年第3期6卷 216-225页

作者： Ning Li Li Guo Bihang Fan State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Key Laboratory of Environmental Change and Natural Disasters Ministry of Education Beijing Normal University College of Global Change and Earth System Science Beijing Normal University

Spatiotemporal patterns of dust storms are affected by climate change through changes in convective instability, regional meteorological characteristics, and local sediment supply. Linking dust storm dynamics to climate change helps the understanding of what controls the initiation of dust storms, and assists the prediction of future dust storm occurrence. This study examines the temporal dynamics of spring dust storms in Inner Mongolia, a major dust source area in East Asia. We found that severe spring dust storms have significantly declined from1954 to 2007. Four dust storm types showed similar decreasing trends from 2001 to 2012. This change in spring dust storm dynamics is attributed to the shift in vegetation green-up dates based on the analysis of a satellite derived vegetation index. Earlier vegetation green-up has a dampening effect on spring dust storms. Suitable environmental conditions for vegetation green-up hinder the emergence of dust storms. This study expands our understanding of the dynamics of spring dust storms in the changing climate through a new perspective on vegetation phenology in the spring.

关键词： Climate change Dust storm dynamics Green-up date Inner Mongolia Vegetation phenology

Expulsive force in the development of C02 sequestration:application of SC-C02 jet in oil and gas extraction

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Frontiers in Energy 2019年第1期13卷 1-8页

作者： Haizhu WANG Gensheng LI Zhonghou SHEN State Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing 102200China

With the rapid development of global economy,an increasing amount of attention has been paid to the emission of greenhouse gases,especially *** recent years,dominated by the governments around the world,several significant projects of CO2 sequestration have been ***,due to the huge investment and poor economic effects,the sustainability of those projects is not *** CO2(SC-CO2)has prominent advantages in well drilling,fracturing,displacement,storage,plug and scale removal within tubing and casing,which could bring considerable economic benefits along with CO2 *** this paper,based on physicochemical properties of SC-CO2 fluid,a detailed analysis of technical advantages of SC-CO2 applied in oil and gas development is ***,the implementation processes of SC-CO2 are also *** the first time,a recycling process is presented in which oil and gas are extracted and the CO2 generated could be restored underground,thus an integrated technology system is *** the recent interests in the development of enhancing hydrocarbon recoveries and CO2 sequestration,this approach provides a promising techni?que that can achieve these two goals simultaneously.

关键词： CO2 sequestration SC-CO2 jet well drilling fracturing oil and gas