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| 1 | Lakes' state and abundance across the Tibetan Plateau显示文摘Understanding the changes in number and areal extent of lakes,as well as their abundance and size distribution is important for assessments of regional and global water resources,biogeochemical cycles,and changes in climate.In this study,changes in lake area greater than 1 km2are mapped using Landsat datasets,spanning the 1970s,1990,2000,and 2010.In addition,high-resolution images(GeoCover Landsat mosaic 2000,with a pixel size of 14.25 m)are used for the first time to map lakes as small as 0.001 km2across the entire Tibetan Plateau(TP).Results show that the numbers and areal extent of individual lakes[1 km2in size show a slight decrease between the 1970s and 1990,followed by a clear increase from 1990 to 2010.Ninety-nine new lakes are identified between the 1970s and 2010,71 of which are found between 1990 and 2010.This indicates the accelerated glacier melt and/or increased difference of precipitation minus evaporation since the 1990s.More than 80%of the lakes show an increase in their area between the 1970s and2010.The lake census,using 2000 imagery,shows that there are 32,843 lakes with a total area of 43,151.08±411.49 km2,which makes up 1.4%of the total area of the TP.Around 96%of all lakes are small,with an area\1 km2,while the 1,204 large lakes([1 km2)account for96%of the total lake area.The TP is subdivided into 12greater drainage basins,and of these the inner TP dominates in terms of the number of lakes(55.03%),the total area of lakes(66%),and lake density(0.026/km2compared to the mean,0.011/km2).A plot of lake abundance against size shows that the size distribution of lakes departs from a typical power-law distribution,but displays such a distribution at the mean elevation(4,715 m),with an r2value of 0.97 and a slope of-0.66.The slopes of the abundance-size equations from each of the 12 greater basins,and from all basins together,are larger than-1,supporting the inference that larger lakes,rather than the small lakes,contribute more to the total lake surface area across the TP.The lake inventory provided in this study,along with the assessment of lake size distribution,have important implications for estimates of water balance,for water resource management,and for lake area estimations in the TP. | Guoqing Zhang Tong Yao Hongjie Xie Kexiang Zhang Fujing Zhu | 2014 | Chinese Science Bulletin2014，59，24： | 33 |
| 2 | Design,modeling and experimental investigation of a magnetically modulated rotational energy harvester for low frequency and irregular vibration显示文摘Vibration energy harvesting is a promising approach for sustainable energy generation from ambience to meet the development of self-powered systems.Here,we propose a novel compact non-resonant magnetically modulated rotational energy harvester(MMR-EH)for low frequency and irregular vibration.Through the rational arrangement of multiple magnetic fields in space,a ring route with low potential energy is established.A movable magnet can be non-contact modulated by the magnetic force to move along the ring route under irregular vibration,which is instrumental in electromechanical energy conversion.A dynamic model of the MMR-EH is developed based on the energy method and verified experimentally.The effects of key parameters on the magnetically modulated route are analysed.The simulation and experimental results demonstrate that the MMR-EH can effectively harvest the energy from ultra-low frequency(3 Hz)and irregular vibration.At a reciprocating vibration frequency of 10 Hz and an amplitude of 20 mm,the harvester can produce an average power of 0.29 mW. | ZHAO LinChuan ZOU HongXiang GAO QiuHua YAN Ge WU ZhiYuan LIU FengRui WEI KeXiang YANG Bin ZHANG WenMing | 2020 | Science China(Technological Sciences)2020，63，10： | 5 |
| 3 | Suppression of multiple modal resonances of a cantilever beam by an impact damper显示文摘Impact dampers are usually used to suppress single mode resonance. The goal of this paper is to clarify the difference when the impact damper suppresses the resonances of different modes. A cantilever beam equipped with the impact damper is modeled. The elastic contact of the ball and the cantilever beam is described by using the Hertz contact model. The viscous damper between the ball and the cantilever beam is modeled to consume the vibrational energy of the cantilever beam. A piecewise ordinary differential-partial differential equation of the cantilever beam is established, including equations with and without the impact damper. The vibration responses of the cantilever beam with and without the impact damper are numerically calculated. The effects of the impact absorber parameters on the vibration reduction are examined. The results show that multiple resonance peaks of the cantilever beam can be effectively suppressed by the impact damper. Specifically, all resonance amplitudes can be reduced by a larger weight ball. Moreover, the impacting gap is very effective in suppressing the vibration of the cantilever beam. More importantly, there is an optimal impacting gap for each resonance mode of the cantilever beam, but the optimal gap for each mode is different. | Xiaofeng GENG Hu DING Kexiang WEI Liqun CHEN | 2020 | Applied Mathematics and Mechanics(English Edition)2020，41，3： | 5 |
| 4 | Power fluctuation and power loss of wind turbines due to wind shear and tower shadow显示文摘 | Binrong WEN Sha WEI Kexiang WEI Wenxian YANG Zhike PENG Fulei CHU | 2017 | Frontiers of Mechanical Engineering2017，12，3： | 4 |
| 5 | Open-circuit Fault-tolerant Control Strategy Based on Five-level Power Converter for SRM System显示文摘Switched reluctance motor power converters are prone to open-circuit faults because it need to withstand large voltages and currents.Due to the small number of traditional asymmetrical half bridge topology switches,it is difficult to carry out fault tolerant control when power converters has an open-circuit fault,resulting in larger output torque ripple.This paper presents a five-level power converter based on the traditional asymmetric half-bridge power converter.The five-level topology has more switching states and can work in multi-level mode.Based on the topology,different excitation and demagnetization voltages can be choose at different speeds.A fault-tolerance strategy is developed to decrease the influence of the open-circuit fault.The five-level power converter has four switches per phase,and two of them will be used in one of the operating mode.So the remaining two of the switches can be used for safe backup,enabling fault-tolerant control when an open-circuit occur.Since each phase of the five-level power converter proposed in this paper is independent of each other,a reasonable control strategy can be used to avoid the unbalance of the midpoint potential.Finally,the topology and fault-tolerant strategy proposed in this paper are verified by simulation and experiment. | Mingyao Ma Kexiang Yuan Qingqing Yang Shuying Yang | 2019 | CES Transactions on Electrical Machines and Systems2019，3，2： | 3 |
| 6 | Comparison and analysis of three estimation methods for soil carbon sequestration potential in the Ebinur Lake Wetland,China显示文摘Based on soil under seven vegetation types,the carbon sequestration potential in the Ebinur Lake wetland was estimated using the maximum value method,the saturation value method,and the classification and grading method.Results indicated that:1)Soil carbon sequestration results for the top 20 cm soil layer were about 1.88 Mt using the maximum value method;the middle level standard of the classification and grading method result was 1.71 Mt.2)Soil carbon sequestration potential in the top 20 cm layer under different vegetation types,evaluated using the saturation value method and the classificationgrading method,ranged from 0.45 to 0.67 Mt,accounting for about 5/16 of the ideal carbon sequestration potential.3)Carbon sequestration potential calculated using the saturation method and the classification method(middle level standard),combining the soil organic carbon increment under different vegetation types in Ebinur Lake wetland,recorded an average growth rate of soil organic carbon around 0.7-1 kg/(hm^2·a).Time required to reach its carbon sequestration potential was 41 to 144 a.These results indicate that soil organic carbon content dynamically changes,and different forms of land use affect soil organic carbon content.The potential and ability of soil carbon sequestration and its mechanism of dynamic change are investigated,providing a scientific basis for understanding regional carbon cycle and climate change in wetlands. | Yonghui WANG Kexiang LIU Zhaopeng WU Li JIAO | 2020 | Frontiers of Earth Science2020，14，1： | 2 |
| 7 | A Belief Propagation Algorithm with Set-Breaking to Lower Error-Floors of Low-Density Parity-Check Codes显示文摘 | MA Kexiang LIYongzhao ZHANG Hailin ZHU Caizhi ZHANG Yuming | 2013 | Chinese Journal of Electronics2013，22，3： | 2 |
| 8 | A recommended rate for application of Chaetomium globosum ND35 fungus fertilizer on poplar plantations in China显示文摘Previous studies showed that Chaetomium globosum ND35 fungus fertilizer can improve the microbial community structure and enzyme activities of replanted soil.However, it remains unclear whether can improve the physiological and ecological characteristics of plants under successive rotation.In this study, we investigated the photosynthetic, physiological, and biochemical indexes including photosynthetic parameters, chlorophyll fluorescence, and chlorophyll content of 1-year-old poplar seedlings under seven different doses(range from 0 to1.67 g kg^(-1)) of C.globosum ND35 fungus fertilizer to study the effects of fungus fertilizer on photosynthesis of Poplar.Our results showed that:(1) With increasing application of fungus fertilizer in replanted soil, chlorophyll content of poplar leaves(Chl) increased, while physiological indexes such as electron transport rate(ETR),net photosynthetic rate(P_n), quantum efficiency(U),nitrate reductase(NR) activity and root vigor initially increased and then declined.Meanwhile, heat dissipation that depended on the xanthophyll cycle declined and nonphotochemical quenching(NPQ) initially increased and then decreased.When the dose of C.globosum ND35 fungus fertilizer was 0.67 g kg^(-1)(T3) and 1.00 g kg^(-1)(T4), excess light energy of photosynthetic apparatus was reduced, and photosynthetic apparatus distributed more light energy to the direction of photochemical reactions,which improved the efficiency of energy use.Plant height and biomass of leaves, stems, and roots were maximum at T3.We conclude that applying appropriate amounts of C.globosum ND35 fungus fertilizer can improve root physiological activity and capacity for use of light by poplar leaves.This can improve the operating states of the photosynthetic apparatus and lead to increased photosynthetic efficiency of poplar leaves and accumulation of dry matter.This suggests a strategy to alleviate the successive rotation obstacle of soil nutrient depletion. | Xuanxuan Xia Kexiang Gao Xianshuang Xing Rui Yang Shuyong Zhang Zilong Du Jing Guo Xia Liu | 2018 | Journal of Forestry Research2018，29，4： | 2 |
| 9 | The Greatest Hosoya Index of Bicyclic Graphs with Given Maximum Degree显示文摘 | Xu Kexiang Gutman I | 2011 | MATCH Commun Math Comput Chem2011，66，3： | 1 |
| 10 | On the Hosoya index and the Merrifield-Simmons index of graphs with a given clique number显示文摘 | Kexiang XU | | 0，，04： | 1 |
| 11 | A key role of microRNA-29b in suppression of osteosarcoma cell proliferation and migration via modulation of VEGF显示文摘 | ZHANG Kexiang ZHANG Chaoyue LIU Li | 2014 | Int J Clin Exp Pathol2014，，7： | 1 |
| 12 | Zagreb indices of graphs显示文摘第一萨格勒布索引 M <潜水艇class=“ a-plus-plus ”> 1 (G)等于顶点的度的广场的和,并且第二萨格勒布索引 M <潜水艇class=“ a-plus-plus ”> 2 (G)等于一些内在的分子的图 G 的邻近的顶点的度的产品的和。在这份报纸,我们在第一萨格勒布索引 M 上获得更低、上面的界限 < 潜水艇 class= “ a-plus-plus ” > G 的 1 (G) 以顶点(n) 的数字,边(m) 的数字,最大的顶点度() ,并且最小的顶点度() 。用这结果,我们在 M 上发现更低、上面的界限 < 潜水艇 class= “ a-plus-plus ” > 2 (G) 。另外,我们 \ 上的现在的更低、上面的界限(M_2 (G)+ M_2 (\bar G )\) 以 n, m,,并且,,,并且,在 \(\bar G\) 表示 G 的补充的地方。而且,我们在第一萨格勒布 coindex \(\bar M_1 (G)\) 和第二萨格勒布 coindex \(\bar M_2 (G)\) 上决定界限。最后,我们给在第一个萨格勒布索引和图 G 的第二个萨格勒布索引之间的一种关系。 | Kinkar Ch. DAS Kexiang XU Junki NAM | 2015 | Frontiers of Mathematics in China2015，10，3： | 1 |
| 13 | Kinetics of Ozonation of Typical Sulfonamides in Water显示文摘Objective To investigate the kinetic rate constants ozone and hydroxyl radicals towards two groups of antimicrobials-sulfadiazine (SD) and sulfamethoxazole (SMX).Methods The solute consumption method was used to detect the rate constants of ozone alone with sulfadiazine and sulfamethoxazole,and tertiary butanol was selected as a scavenging agent and pH was adjusted to 2.5 by adding orthophosphate buffers (OB);and the competition kinetics studying methodwith nitrobenzene as a reference was applied to measure the rate constants of hydroxyl radicals towards sulfadiazine and sulfamethoxazole,and pH was adjusted to 7.0 by adding OB.Results The rate constants of SD and SMX with ozone alone were 261 mol ‐1 dm 3 s ‐1 and 303 mol ‐1 dm3 s ‐1 by calculating in low reaction system.The rate constants of hydroxyl radicals with SD and SMX were 2.2×1010 mol ‐1 dm 3 s ‐1 and 2.7×1010 mol ‐1 dm 3 s ‐1,respectively.Moreover,the rate constants of hydroxyl radicals with SMX were found to have increased from 3.6×109 mol ‐1 dm 3 s ‐1 to 2.8×1010 mol ‐1 dm 3 s ‐1 with pH value rising from 5.0 to 7.8.Conclusion SMX and SD are both refractory to ozone oxidation alone,and are liable to be degraded by hydroxyl radicals,and the rate constants of SMX with the hydroxyl radical slightly increases with pH rise. | SUI MingHao XING SiChu ZHU ChunYan SHENG Li LU KeXiang GAO NaiYun | 2011 | Biomedical and Environmental Sciences2011，24，3： | 1 |
| 14 | The resonance peak theory of reflection Guided-mode Resonance Filters显示文摘 | Fu Kexiang Wang Zhiheng Zhang Qizhi | 1999 | Chinese Journal of Lasers1999，8，4： | 1 |
| 15 | The Greatest Hosoya Index of Bicyclic Graphs with Given Maximum Degree显示文摘 | Xu Kexiang Gutman I | 2011 | MATCH Commun Math Comput Chem2011，66，3： | 1 |
| 16 | Explicit solvent model for spectral shift of acrolein and simulation with molecular dynamics显示文摘By introducing the concept of spring energy of permanent dipole and taking the conforma-tions of solvent molecules into account,the formulas of electrostatic solvation energy in equilibrium and nonequilibrium are derived from the explicit solvent scheme,with the spatial distribution of the discrete permanent charges and induced dipoles of the sol-vent molecules involved. The energy change of sol-ute due to the variation of wave function from the case of vacuum to that in solution is estimated by treating the solvent effect as external field in the it-eration cycles of the self-consistent field. The ex-pression for spectral shift is deduced and applied to the processes of light absorption and emission in solution. According to the new formulations,the av-eraged solvent electrostatic potential/molecular dy-namics program is modified and adopted to investi-gate the equilibrium solvation energy of water mole-cule and spectral shift of acrolein. | ZHU Quan LIU Jifeng FU Kexiang HAN Keli LI Xiangyuan | 2006 | Chinese Science Bulletin2006，51，24： | 1 |
| 17 | Experimental investigation on vibration characteristics of sandwich beams with magnetorheological elastomers cores显示文摘 | WEI Kexiang MENG Guang ZHANG Wenming | 2008 | Journal of Central South University of Technology2008，，： | 1 |
| 18 | The hyper-Wiener index of bicyclic graphs显示文摘 | Feng Lihua Liu Weijun Xu Kexiang | 2011 | Utilitas Math2011，84，： | 1 |
| 19 | Thermodynamics for nonequilibrium solvation and numerical evaluation of solvent reorganization energy显示文摘This work presents a thermodynamic method for treating nonequilibrium solvation. By imposing an extra electric field onto the nonequilibrium solvation system, a virtual constrained equilibrium state is prepared. In this way, the free energy difference between the real nonequilibrium state and the con-strained equilibrium one is simply the potential energy of the nonequilibrium polarization in the extra electronic field, according to thermodynamics. Further, new expressions of nonequilibrium solvation energy and solvent reorganization energy have been formulated. Analysis shows that the present formulations will give a value of reorganization energy about one half of the traditional Marcus theory in polar solvents, thus the explanation on why the traditional theory tends to overestimate this quantity has been found out. For the purpose of numerical determination of solvent reorganization energy, we have modified Gamess program on the basis of dielectric polarizable continuum model. Applying the procedure to the well-investigated intramolecular electron transfer in biphenyl-androstane-naphthyl and biphenyl-androstane-phenanthryl systems, the numerical results of solvent reorganization energy have been found to be in good agreement with the experimental fittings. | LI XiangYuan WANG JingBo MA JianYi FU KeXiang HE FuCheng | 2008 | Science China Chemistry2008，51，12： | 1 |
| 20 | The greatest Hosoya index of bicyclic graphs with given maximum degree显示文摘 | Xu Kexiang Gutman I | | 0，，： | 1 |
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