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Explicit Piecewise Smooth Solutions of Landau-Lifshitz Equation with Discontinuous External Field

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Acta Mathematicae Applicatae Sinica 2009年第1期25卷 61-74页

作者： gan-shan yang Yun-zhang Zhang Li-min Liu Institute of Mathematics Science Yunnan Normal University Kunming 650092 China Department of Mathematics Yunnan National University Kunming 650031 China Faculty of Science Xi'an Jiaotong University Xi'an 710049 China College of Mathematics and Physics Chongqing University Chongqiong 400030 China

In this paper, we shall construct some explicit piecewise smooth （global continuous） solutions as well as blow up solutions to the multidimensional Landau-Lifshitz equation, subject to the external magnetic fields being both discontinuous and unbounded. When the external magnetic field is continuous, some explicit exact smooth solutions and blow up solution are also constructed. We also establish some necessary and sufficient conditions to ensure that the solution of multidimensional Landau-Lifshitz equation with external magnetic field converges to the solution of equation without external magnetic field when the external magnetic field tends to zero.

关键词： Multidimensional Landau-Lifshitz equation discontinuous external field piecewise smoothsolution

多维Landau-Lifshitz方程的δ-黏性解

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数学学报（中文版） 2006年第4期49卷 721-736页

作者：郭柏灵杨干山北京应用物理与计算数学研究所非线性研究中心北京100088 云南民族大学数学系昆明650031

本文引入δ-黏性上解,δ-黏性下解和δ-黏性解的概念,给出一些相关性质,利用这些性质证明取值于三维单位球面的多维Landau-Lifshitz方程的δ-黏性上解和δ-黏性下解的存在性,揭示存在两个不相交的开子集M和N,使得δ-黏性上解和δ-黏性... 详细信息

本文引入δ-黏性上解,δ-黏性下解和δ-黏性解的概念,给出一些相关性质,利用这些性质证明取值于三维单位球面的多维Landau-Lifshitz方程的δ-黏性上解和δ-黏性下解的存在性,揭示存在两个不相交的开子集M和N,使得δ-黏性上解和δ-黏性下解在M内任一紧子集上趋于(0,1,0),在N内任一紧子集上趋于(0,-1,0)．

关键词：多维Landau-Lifshitz方程 δ-黏性上(下)解平均曲率

The prediction formula and a risk-based sensor scheduling method in target detection with guiding information

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Defence Technology（防务技术） 2020年第2期16卷 447-452页

作者： Ce Pang gan-lin shan Army Engineering University Shijiazhuang 050000People's Republic of China

Sensor scheduling is used to improve the sensing performance in the estimation of targets’***,few papers are on the sensor scheduling for target detection with guiding *** letter can remedy this deficiency.A risk-based target detection method with guiding information is provided firstly,based on which,the sensor scheduling approach is aiming at reducing the risk and uncertainty in target detection,namely risk-based sensor scheduling *** should be stressed is that the Prediction Formula in sensor scheduling is ***,some examples are conducted to stress the effectiveness of this proposed method.

关键词： Sensor scheduling Target detection Operational risk Information guiding

Acetalization of carbonyl compounds with 2,2,4-trimethyl-1,3-pentanedio catalyzed by novel carbon based solid acid catalyst

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Journal of Natural Gas Chemistry 2008年第2期17卷 149-152页

作者： Ling Liu Yuechang Zhao shan gan Xuezheng Liang Jianguo yang Mingyuan He shanghai Key Laboratory of Green Chemistry and Chemical Process East China Normal University Shanghai 200062 China

The synthesis of 2, 4-diisopropyl-5,5-dimethy1- 1.3-dioxane through the acetalization of isobutyraldehyde with 2, 2, 4-trimethy1-1,3-pentanediol （TMPD） catalyzed by the novel carbon based acid was first carried out. High conversion （≥98%） and specific selectivity were obtained using the novel carbon based acid, which kept high activity after it was reused 5 times. Moreover. the catalyst could be used to catalyze the acetalization and ketalization of different aldehydes and ketones with superior yield. The yield of several products was over 90%. The novel heterogeneous catalyst has the distinct advantages of high activity, strikingly simple workup procedure, non-pollution, and reusability, which will contribute to the success of the green process greatly.

关键词： TMPD acetalization carbon based solid strong acid isobutylaldehyde

Structural Properties of Early-Type Galaxies from the SDSS DR2

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Chinese Journal of Astronomy and Astrophysics 2008年第5期8卷 503-521页

作者： Feng-shan Liu Zu-gan Deng Hong Wu Xiao-yang Xia National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate School of Chinese Academy of Sciences Beijing 100049 China Department of Physics Tianjin Normal University Tianjin 300074 China

Two-dimensional bulge/disk light decomposition with GIM2D in both the r- and g-bands has been applied to a sample of 129 early-type galaxies brighter than 13.5 magnitude in the r-band, selected from the Sloan Digital Sky Survey Data Release 2. Intensity-weighted Fourier coefficient （α4/α） was also derived for each sample galaxy. Our analysis shows that there are correlations between bulge-to-total light ratio （B/T） with bulge Sersic index nB and between bulge and disk scale sizes. Isophotal shape parameter （α4/α） is not correlated with BIT and riB. Both bulge and disk components satisfy a color-magnitude relation. The space Fundamental Plane analysis shows that galaxies with larger B/T tend to lie tighter and closer to the line of k1 ＋ k2 = 8 （the so-called ＂zone of avoidance＂） than the galaxies with smaller B/T. It indicates that existence of the disk component may lead to scatter of the distribution on the Fundamental Plane. Our analysis also shows that k1 ＋ k2 correlates with （g-r） color and B/T, but does not correlate with （α4/α） for early-type galaxies. The fitted parameters and other retrieved parameters used in this paper for all sample galaxies are available online.

关键词： galaxies elliptical and lenticular, cD -galaxies photometry -galaxies structure - galaxies

Enhanced precipitation responses over the Tibetan Plateau following future Tambora-size volcanic eruption

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Advances in Climate Change Research 2024年第5期15卷 845-858页

作者： Xin-Jun gan Lin-shan yang Meng ZUO Fei LIU Chao-Chao GAO College of Environmental and Resource Science Zhejiang UniversityHangzhou 310058China Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control Hangzhou 310058China State Key Laboratory of Severe Weather and Institute of Tibetan Plateau Meteorology Chinese Academy of Meteorological SciencesBeijing 100081China School of Atmospheric Sciences&Key Laboratory of Tropical Atmosphere Ocean System Ministry of Education Sun Yat-sen UniversiyZhuhai 519082China Southern Marine Science and Engineering Guangdong Laboratory Sun Yat-sen UniversityZhuhai 519082China

Hydroclimate over the Tibetan Plateau(TP)notably influences the eco-environment of the Northern *** its high elevation and complex topography,the climate in the TP shows a high sensitivity to anthropogenic warming and volcanic-induced *** mechanism by which a future volcanic or similar radiative perturbation affects precipitation in the TP under an anthropogenic warming climate must be addressed not only to enable regional adaptation but deepen our understanding of how a climate system evolves under such a dual ***,based on the Community Earth System Model version 1.2 and ensemble simulations under pre-industrial and RCP8.5 scenarios,we showed that a Tambora-sized volcanic perturbation led to severe rainfall reduction over the south TP in the following summer(June-August).Evaporation response accounted for a minor and relatively constant share of precipitation reduction following the Clausius-Clapeyron scaling,whereas dynamic processes triggered an El Nino-like response in the eastern equatorial Pacific,which suppressed the Walker and Hadley circulation and contributed to drying *** warming renders the post-Tambora hydroclimate responses with 30%higher severity as a result of the increased climatological moisture content and intensified El Nino response,which enhanced hydroclimate sensitivity and attenuated monsoon *** results illustrate the amplification effect of global warming on the plateau's hydroclimate responses to external forcings,which may add another layer of uncertainty on climate adaptation in this already complex region.

关键词： Tibetan Plateau The community earth system model Hydrological response Tambora eruption El Nino

A non-myopic scheduling method of radar sensors for maneuvering target tracking and radiation control

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Defence Technology（防务技术） 2020年第1期16卷 242-250页

作者： gan-lin shan Gong-guo Xu Cheng-lin Qiao Department of Electronic and Optical Engineering Army Engineering UniversityShijiazhuang 050003China

In decades,the battlefield environment is becoming more and more complex with plenty of electronic ***,in order to improve the survivability of radar sensors and satisfy the requirement of maneuvering target tracking with a low probability of intercept,a non-myopic scheduling is proposed to minimize the radiation cost with tracking accuracy *** first,the scheduling problem is formulated as a partially observable Markov decision process(POMDP).Then the tracking accuracy and radiation cost over the future finite time horizon are predicted by the posterior carmer-rao lower bound(PCRLB) and the hidden Markov model filter,***,the proposed scheduling is implemented efficiently by utilizing the branch and bound(B&B) pruning *** results show that the performance of maneuvering target tracking was improved by the improved interacting multiple model(IMM),and the scheduler time and maximum memory consumption were significant reduced by the present B&B pruning algorithm without losing the optimal solution.

关键词： Non-myopic scheduling Radiation control PCRLB POMDP Branch and bound

Leaf phenotypic variation of endangered plant Tetracentron sinense *** influence of geographical and climatic factors

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Journal of Forestry Research 2021年第2期32卷 623-636页

作者： yang Li shan Li Xueheng Lu Qinqin Wang Hongyan Han Xuemei Zhang Yonghong Ma Xiaohong gan Key Laboratory of Southwest China Wildlife Resources Conservation(Ministry of Education) College of Life ScienceChina West Normal UniversityNanchong 637009China Institute of Plant Adaptation and Utilization in Southwest Mountain China West Normal UniversityNanchong 637009China

To analyze the degree and pattern of phenotypic variation in leaves of Tetracentron sinense Oliv from the perspective of genetic and environmental adaptation and thus contribute to effective evidence-based conservation and management strategies for germplasm resources,we measured 17 morphological and epidermal micromorphological leaf traits from 24 natural populations of *** analysis of variance,multiple comparison,principal component analysis(PCA),cluster analysis,and correlation analysis were used to explore phenotypic leaf variation among and within populations and potential correlations with geographic and environmental *** were significant differences in 17 leaf phenotypic traits among and within *** mean phenotypic differentiation coefficient of the 17 traits was 56.34%,and the variation among populations(36.4%)was greater than that within populations(27.2%).The coefficient of variation(CV)of each trait ranged from 4.6 to 23.8%,and the mean was 11.8%.Phenotypic variation of leaves was related to environmental factors such as average annual sunshine hours,average July temperature,and average annual *** variation changed along gradients of longitude,latitude,and *** PCA clustered the 24 natural populations into four *** study suggests that phenotypic variation in *** occurred primarily among populations,with moderate levels of phenotypic differentiation among populations and low levels of phenotypic variation within *** plant’s poor adaptability to the environment is likely an important contributor to its ***,conservation strategies are proposed to protect and manage the natural populations of ***.

关键词： Tetracentron sinense Leaf phenotypic traits Phenotypic variation Natural population Endangered plant

A new energy efficient management approach for wireless sensor networks in target tracking

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Defence Technology（防务技术） 2021年第3期17卷 932-947页

作者： Ce Pang Gong-guo Xu gan-lin shan Yun-pu Zhang Army Engineering University Hebei Shijiazhuang050003China

This paper mainly studied the problem of energy conserving in wireless sensor networks for target tracking in defensing combats. Firstly, the structures of wireless sensor nodes and networks were illustrated;Secondly, the analysis of existing energy consuming in the sensing layer and its calculation method were provided to build the energy conserving objective function;What’s more, the other two indicators in target tracking, including target detection probability and tracking accuracy, were combined to be regarded as the constraints of the energy conserving objective function. Fourthly, the three energy conserving approaches, containing optimizing the management scheme, prolonging the time interval between two adjacent observations, and transmitting the observations selectively, were introduced;In addition, the improved lion algorithm combined with the Logistic chaos sequence was proposed to obtain sensor management schemes. Finally, simulations had been made to prove the effectiveness of the proposed methods and algorithm.

关键词： Wireless sensor networks Target searching Target tracking Energy efficiency Lion algorithm