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Journal of Systematics and Evolution 2009年第3期47卷 220-225页

作者： Qin-Wen LIN Zhi-Xiang ZHANG (College of Biological Sciences and Biotechnology, beijing forestry university, beijing 100083, china) (College of Biological Sciences and Biotechnology Beijing Forestry University Beijing 100083 China)

Microtropis macrocarpa C.Y. Cheng & T.C. Kao has been treated as a synonym of Microtropis macrophylla Merr. & Freeman in most taxonomic reports in china. According to our study, M. macrocarpa is an independent species endemic to Yunnan, china. Microtropis macrophylla and Microtropis pachyphylla Merr. & Freeman should be treated as synonyms of Microtropis longifolia Wall. ex Kurz. M. macrocarpa is also identified as a critically endangered species, CR B1ab (i,ii,iii,v), based on the IUCN Red List Categories and Criteria. The foliar surface, anther and pollen structures were also observed with a scanning electron microscope.

关键词： Celastraceae foliar epidermis IUCN Red List Microtropis pollen.

A case study of spatial heterogeneity of soil moisture in the Loess Plateau,western china:A geostatistical approach

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International Journal of Sediment Research 2009年第1期24卷 63-73页

作者： BI Huaxing1,2,LI Xiaoyin3,LIU Xin3,GUO Mengxia3,and LI Jun3 1 Prof., College of Soil and Water Conservation, beijing forestry university, beijing 100083, china, Key Laboratory of Soil and Water Conservation and Desertification Combating, Ministry of Education, beijing 100083, china 2 Researcher, Ji-xian National Ecological Station of china, beijing 100083, china 3 Graduate student, College of Soil and Water Conservation, beijing forestry university, beijing 100083, china Prof. College of Soil and Water Conservation Beijing Forestry University Beijing 100083 China Key Laboratory of Soil and Water Conservation and Desertification Combating Ministry of Education Beijing 100083 China Researcher Ji-xian National Ecological Station of China Beijing 100083 China Graduate student College of Soil and Water Conservation Beijing Forestry University Beijing 100083 China

Soil moisture distribution shows highly variation both spatially and temporally. This study assesses the spatial heterogeneity of soil moisture on a hill-slope scale in the Loess Plateau in West china by using a geostatistical approach. Soil moisture was measured by time-domain reflectometry(TDR) in 313 samples. Two kinds of sampling scales were used(2 x 2 m and 20 x 20 m) at two soil layers(0-30 cm and 30-60 cm). The general characteristics of soil moisture were analyzed by a classical statistics method,and the spatial heterogeneity of soil moisture was analyzed using a geostatistical approach. The results showed that the spherical model is the best-fit model to simulate soil moisture on the experimental hill-slope. The parameters of this model indicated that the spatial dependence of soil moisture in the selected hill-slope was moderate. Even the 2 x 2 m sampling scale was too coarse to show the detailed spatial variances of soil moisture in this area. The dependent distance increased from 27.4 m to 494.16 m as the sampling scale became coarse(from 2 x 2 m to 20 x 20 m). A map of soil moisture was generated by using original soil moisture data and interpolated values determined by the Kriging method. The average soil moisture(area weighted) in the different layers of soil was calculated on the basis of this map(10.94% for the 0-30 cm soil layer,11.88% for the 30-60 cm soil layer). This average soil moisture is lower than the corresponding average effective soil moisture,which suggests that the soil moisture is not sufficient to support vegetation in this area.

关键词： Spatial heterogeneity Soil moisture Geostatistics Loess Plateau of china

Evolution of Nielsen-Olesen's String from Chern-Simons Field Theory

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Communications in Theoretical Physics 2007年第7期48卷 147-150页

作者： DUAN Yi-Shi Institute of Theoretical Physics,Lanzhou university,Lanzhou 730000,chinaSHI Xu-Guang College of Science,beijing forestry university,beijing 100083.china Institute of Theoretical Physics Lanzhou University Lanzhou 730000 China College of Science Beijing Forestry University Beijing 100083 China

We study the topology of Nielsen-Olesen's local field theory of single dual *** on the Chern-Simons field theory in three dimensons,we find many strings that can form world sheets in four *** stringshave important relation to the zero point of the complex scalar *** world sheets of strings can be expressed bythe topological invariant number,Hopf index,and Brower ***-Goto's action is obtained from the Nielsen'saction definitely by using φ-mapping theory.

关键词： φ-mapping theory dual string Nambu-Goto’s action Hopf index Brower degree

Preparation and characterization of poly(vinylidene fluoride) composite membranes blended with nano-crystalline cellulose

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Progress in Natural Science:Materials International 2012年第3期22卷 250-257页

作者： Haolong Bai, Xuan Wang, Yitong Zhou, Liping Zhang College of Material Science and Technology, beijing forestry university, beijing 100083, china College of Material Science and Technology Beijing Forestry University Beijing 100083 China

Poly(vinylidene fluoride) (PVDF) composite membranes blended with nano-crystalline cellulose (NCC) for ultrafiltration were prepared by a Loeb-Sourirajan (L-S) phase inversion process. The effects of NCC concentration on the membrane performances were investigated. Surface chemical compositions, surface and cross-section morphologies, degree of crystallinity and the thermal stability of the membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA) respectively. The mechanical properties of the membranes were also investigated. All the experimental results indicated that the properties of the composite membranes were improved due to the addition of NCC. The pure water flux of composite membranes can reach 230.8 L/(m2 h) and increase up to 47.5% compared with pure PVDF membranes. At the same time, the rejection ratio of a bovine serum albumin solution (1 g/L) was up to 92.5%. The porosity and the mean pore size of the composite membranes were 65% and 49 nm, respectively. Due to the addition of NCC, the degree of crystallinity was increased to 52.1% resulting in the enhanced mechanical properties. A typical asymmetric structure, which was composed of sponge-like dense layer and finger-like microporous support layer, was observed in SEM images of composite membranes.

关键词： Poly(vinylidene fluoride) (PVDF) Nano-crystalline cellulose (NCC) Composite membranes Improved performances

Adaptive neural control based on HGO for hypersonic flight vehicles

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Science china(Information Sciences) 2011年第3期54卷 511-520页

作者： XU Bin 1,2 , GAO DaoXiang 3 & WANG ShiXing 1 1 Department of Computer Science and Technology, Tsinghua university, beijing 100084, china 2 Autonomous System Lab, ETH Zurich Zurich 8092, Switzerland 3 School of Technology, beijing forestry university, beijing 100083, china Department of Computer Science and Technology Tsinghua University Beijing China Autonomous System Lab ETH Zurich Zurich Switzerland School of Technology Beijing Forestry University Beijing China

This paper describes the design of adaptive neural controller for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV) which are decomposed into two functional systems, namely the altitude subsystem and the velocity subsystem. For each subsystem, one adaptive neural controller is investigated based on the normal output-feedback formulation. For the altitude subsystem, the high gain observer (HGO) is taken to estimate the unknown newly defined states. Only one neural network (NN) is employed to approximate the lumped uncertain system nonlinearity during the controller design which is considerably simpler than the ones based on back-stepping scheme with the strict-feedback form. The Lyapunov stability of the NN weights and filtered tracking error are guaranteed in the semiglobal sense. Numerical simulation study of step response demonstrates the effectiveness of the proposed strategy in spite of system uncertainty.

关键词： adaptive neural control hypersonic flight vehicle high gain observer output-feedback

Mechanisms of invasive population establishment and spread of pinewood nematodes in china

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Science china(Life Sciences) 2009年第6期52卷 587-594页

作者： XIE BingYan1,CHENG XinYue2,SHI Juan3,ZHANG QingWen4,DAI ShuMing1,CHENG Fei Xue2 & LUO YouQing3 1 Institute of Vegetables and Flowers,Chinese Academy of Agricultural Sciences,beijing 100081,china 2 beijing Normal university,beijing 100875,china 3 beijing forestry university,beijing 100083.china 4 Chinese Agricultural university,beijing 100094,china Institute of Vegetables and Flowers Chinese Academy of Agricultural Sciences Beijing China beijing Normal university Beijing China beijing forestry university Beijing China Chinese Agricultural university Beijing China

This paper summarizes the results of our study of the pinewood nematode(Bursaphelenchus xylophi-lus).By population genetic analysis,it was determined that there was no genetic bottle caused by the founder effect and genetic drift in the Chinese invasive *** invasions with large amounts of nematodes from different sources led to rich genetic diversity in the invasive *** high genetic diversity in the invasive process may be one of the genetic mechanisms in its successful *** testing interspecies competition,it was shown that,with high fecundity and a strong competitive ability,*** outcompeted the native species *** in the natural ecosystem during the invasion *** displacement may be one of the ecological mechanisms of ***'s *** addition,an unequal interspecific hybridization with intro-gress was in favor of the invasive species which also accelerated the replacement of *** by *** structures,functions and evolutions of a few important genes that are closely related to the ecological adaptation of pinewood nematodes were studied to explore the molecular mechanism of its ecological ***,the resistance and resilience mechanism of the pine ecosystem invaded by pinewood nematodes was also *** results of these studies uncovered a portion of the genetic and ecological mechanisms of PWN's successful invasion and laid a foundation for further study to obtain a comprehensive interpretation of the mechanisms of the nematode *** results also provided a scientific basis for effectively controlling the occurrence and spread of pine wilt disease which is caused by *** aspects requiring further investigation are considered.

关键词： pinewood nematode bioinvasion genetic diversity ecological adaptation resistance resilience

Detection of the urban heat island in beijing using HJ-1B satellite imagery

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Science china Earth Sciences 2010年第S1期53卷 67-73页

作者： YANG Jun1,GONG Peng2,ZHOU JinXing3,HUANG HuaBing2 & WANG Lei2 1 Key Laboratory of Silviculture and Conservation,Ministry of Education,beijing forestry university,beijing 100083.china 2 State Key Laboratory of Remote Sensing Science,jointly sponsored by the Institute of Remote Sensing Applications,Chinese Academy of Sciences and beijing Normal university,beijing 100101,china 3 Institute of Desertification Studies,Chinese Academy of forestry,beijing 100091 china Key Laboratory of Silviculture and Conservation Ministry of Education Beijing Forestry University Beijing China State Key Laboratory of Remote Sensing Science jointly sponsored by the Institute of Remote Sensing Applications Chinese Academy of Sciences and Beijing Normal University Beijing China Institute of Desertification Studies Chinese Academy of Forestry Beijing China

Satellite images are used extensively in studying the urban heat island(UHI) *** evaluated the suitability of thermal infrared(TIR) data from the HJ-1B satellite for detecting UHI using a case study in *** modified algorithms for retrieving the land surface temperature(LST) from HJ-1B data were *** results were compared with LST images derived from a Landsat TM thermal band and the MODIS LST *** spatial pattern of UHI generated using HJ-1B data matched well with that produced using TM and MODIS *** the two algorithms,the mono-window algorithm performed better but further tests are *** more frequent coverage than TM and higher spatial resolution than MODIS,the HJ-1B TIR data present a unique opportunity to study thermal environments in cities in china and neighboring countries.

关键词： surface temperature NDVI mono-window algorithm single-channel algorithm

Landscape ecological assessment and eco-tourism development in the South Dongting Lake Wetland, china

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Journal of Environmental Sciences 2003年第2期15卷 271-278页

作者： HE Ping 1,2, WANG Bao-zhong 1,3 (1.Central South forestry university, Zhuzhou 412006, china 2.china International Engineering Consulting Corporation, beijing 100044, china 3.Nanjing university, Nanjing 210093, china Central South forestry university Zhuzhou 412006

As an important resource and the living environment of mankind, wetland has become gradually a highlight, strongly concerned and intensively studied by scientists and sociologists. The governments in the world and the whole society have been paying more and more attention on it. The Dongting Lake of china is regarded as an internationally important wetland. For a rational development and protection of the wetland, an investigation and studied on its resources and its value to tourism in the South Dongting Lake was conducted, to create an assessment system of the ecological landscapes, and to evaluate qualitatively and quantitatively the value of wetland landscape to the eco-tourism. The results showed that the scenic value of the South Dongting Lake Wetland satisfied the criterion of AAAA grade of china national scenic attraction. The eco-tourism value of the landscape cultures in the South Dongting Lake Wetland was discussed with emphasis. It were formulated that a principle and frame of sustainable exploitation of the wetland landscapes and it was proposed as well that establishing a Wetland Park and developing eco-tourism in the South Dongting Lake. Wetland is a fragile ecosystem with low resistance to the impact of the exploitation. Thus, we must pay intensively attention to the influence of exploitation on the landscape, take the ecological risk in account to employ a right countermeasure and avoid the negative affection.

关键词： South Dongting Lake wetland landscape eco-tourism Wetland Park ecological assessment

Study on Community Diversity of Coastal Shelter Forest in Jiaonan

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Chinese Journal of Population,Resources and Environment 2005年第3期3卷 42-47页

作者： Xu Jingwei 1,2, Li Chuanrong 3, Li Qi 4, Zheng Li 3, & Wang Weidong 1 1 beijing forestry university,beijing 100871,china 2 Shandong Acdemy of forestry, Jinan 250014, china 3 College of forestry, Shandong Agricultural university, Taian 271018, china 4 Shandong Normal university, Jinan 250014, china beijing forestry university Beijing 100871 China Shandong Acdemy of forestry Jinan 250014 China College of forestry Shandong Agricultural University Tatan 271018 China Shandong Normal university Jinan 250014 China

Based on the research of the plots in coastal areas in Jiaonan city, Shandong Province, the indices of richness, evenness and diversity of different community types are analyzed. The results show that: The richness indices indicates that arbor layers are close to shrub layers, and both are lower than herbage layers; the ranges among communities vary a little except those of the arbor ones. Mostly the biodiversity indices reveal that herbage, the arbor, the shrub; Biodiversity of communities has great influences on microclimate to a certain extent and is under the control of regional environment.

关键词： coastalshelterforest richness biodiversity index microclimate

Fuzzy tracking control design for hypersonic vehicles via T-S model

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Science china(Information Sciences) 2011年第3期54卷 521-528页

作者： GAO DaoXiang 1 & SUN ZengQi 2 1 School of Technology, beijing forestry university, beijing 100083, china 2 State Key Laboratory of Intelligent Technology and System, Department of Computer Science and Technology, Tsinghua university, beijing 100084, china School of Technology Beijing Forestry University Beijing China State Key Laboratory of Intelligent Technology and System Department of Computer Science and Technology Tsinghua University Beijing China

The main focus of this paper is on designing a T-S fuzzy controller for the hypersonic vehicle. The longitudinal dynamics of the vehicle are studied using time-scale decomposition to reduce the complexity of T-S modeling. The dynamic inversion with PI control technique is applied for the slow dynamics to derive the flight path angle command and throttle setting by taking the pilot altitude and velocity command as its inputs. The T-S fuzzy controller is designed for the fast dynamics to derive the elevator deflection to track the flight path angle command. The discrepancy between the T-S model and real vehicle model is considered by using sliding mode control for the system stability. Simulation results are included to show the effectiveness of the controller.

关键词： fuzzy control T-S model sliding mode control hypersonic vehicle