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Response of soil microorganisms to vegetational succession in Ziwuling Forest

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Frontiers of Environmental Science & Engineering 2009年第4期3卷 421-427页

作者： Hong ZHANG Jialong LU shiwei zhao College of Resource and Environment Northwest A&F UniversityYangling 712100China Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water ResourcesYangling 712100China

This study investigates the changes in soil microbial populations as vegetational succession progress from abandoned farmland to climax forest in the Ziwuling Forest,which is located in the northern part of the Loess Plateau,*** organic C and total extractable N between the fumigated and non-fumigated soils were assumed to be released from soil *** microbial C was calculated using Kec=0.38 and microbial N was calculated using Ken=*** released P was converted to microbial biomass P using Kep=*** bacteria,fungi,and actinomycetes increased as the vegetational succession *** C was of the highest amount in *** C,N,and P generally increased from abandoned land to climax *** results indicated significant(P<0.05)diversities of soil microbial biomass under different *** was a significant correlation between microbial biomass and soil *** about soil microbial populations is important for forecasting vegetational succession and determining the ecological condition of the environment.

关键词： soil microorganisms vegetational succession Ziwuling Forest

Random packing of tetrahedral particles using the polyhedral discrete element method

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Particuology 2015年第6期13卷 109-117页

作者： shiwei zhao Xiaowen Zhou Wenhui Liu Chengguang Lai School of Civil Engineering and Transportation South China University of Technology Guangzhou 510640 China State Key Laboratory of Subtropical Building Science Guangzhou 510640 China Key Laboratory of Water Cycle and Water Security in Southern China of Guangdong Higher Education Institutes Cuangzhou 510275 China

The random packing of tetrahedral particles is studied by applying the discrete element method （DEM）, which simulates the effects of friction, height ratio, and eccentricity. The model predictions are ana- lyzed in terms of packing density and coordination number （CN）. It is demonstrated that friction has the maximal effect on packing density and mean CN among the three parameters. The packing den- sity of the regular tetrahedron is 0.71 when extrapolated to a zero friction effect. The shape effects of height ratio and eccentricity show that the regular tetrahedron has the highest packing density in the family of tetrahedra, which is consistent with what has been reported in the literature. Compared with geometry-based packing algorithms, the DEM packing density is much lower. This demonstrates that the inter-particle mechanical forces have a considerable effect on packing. The DEM results agree with the published experimental results, indicating that the polyhedral DEM model is suitable for simulating the random packing of tetrahedral particles.

关键词： Discrete element method Random packing Tetrahedral particle Coordination number Packing density

Aero-optic imaging deviation prediction based on ISSA-ELM

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Optoelectronics Letters 2023年第7期19卷 425-431页

作者： XU Liang zhao shiwei WANG Tao Tianjin Key Laboratory for Control Theory&Applications in Complicated Systems School of Electrical Engineering and AutomationTianjin University of TechnologyTianjin 300384China School of Intelligent Engineering Sun Yat-sen UniversityGuangzhou 510275China

When the aircraft is moving at high speed in the atmosphere,aero-optical imaging deviation will appear due to the influence of aero-optical *** order to achieve real-time compensation during the flight of the aircraft,it is necessary to analyze and predict the obtained imaging deviation *** order to improve the search speed and accuracy of the prediction algorithm and the ability to jump out of local optimum,in this paper,an improved sparrow search algorithm optimized extreme learning machine(ISSA-ELM) neural network model is proposed to predict the aero-optical imagine ***,the performance of ISSA-ELM,ELM neural network and SSA-ELM neural network was *** results showed that compared with ELM and SSA-ELM algorithms,the convergence speed of ISSA-ELM was significantly enhanced,and the accuracy of data prediction was also significantly improved.

关键词： effect. deviation extreme

Research of line-of-sight angle on aero-optic imaging deviation for vehicles flying at 40—60 km

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Optoelectronics Letters 2023年第4期19卷 242-247页

作者： XU Liang zhao shiwei WANG Tao Tianjin Key Laboratory of Complex Control Theory and Application School of Electronic Engineering and AutomationTianjin University of TechnologyTianjin 300384China Foreign Cooperation Projects Department PetroChina Dagang Oilfield CompanyTianjin 300280China

Aero-optical imaging deviation is a kind of optical effect,aiming at a conical *** paper analyzes the influence of the aircraft on the imaging deviation with the change of altitude and line-of-sight *** this paper,the relationships between imaging deviation and altitude as well as line-of-sight angle are analyzed,and the coupling relationship between altitude and line-of-sight angle is *** give the imaging deviation results of 5°—75°line-of-sight *** analysis shows that when the line-of-sight angle is in the range of 5°—35°,the imaging deviation is more sensitive,while the line-of-sight angle is in the range of 35°—75°,the imaging deviation is relatively flat,and the imaging deviation does not gradually decrease with the increase of line-of-sight angle,but there is a turning point in the middle of 5°—75°.The imaging deviation decreases first and then increases,and the turning point of line-of-sight angle is closely related to height.

关键词： deviation angle turning

Coupled effects of particle overall regularity and sliding friction on the shear behavior of uniformly graded dense sands

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第3期14卷 873-885页

作者： Jiayan Nie shiwei zhao Yifei Cui Yu Wang State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China South China Institute of Geotechnical Engineering South China University of TechnologyGuangzhou510640China Key Laboratory of Mountain Hazards and Surface Process Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu610041China University of Chinese Academy of Sciences Beijing100049China

Particle morphology has been regarded as an important factor affecting shear behaviors of sands,and covers three important aspects,*** form(overall shape),local roundness(large-scale smoothness),and surface texture(roughness)in terms of different observation *** features of different aspects can be independent of each other but might have coupled effects on the bulk behavior of sands,which has been not explored thoroughly *** paper presents a systematic investigation of the coupled effects of the particle overall regularity(OR)and sliding friction on the shear behavior of dense sands using three-dimensional(3D)discrete element method(DEM).The representative volume elements consisting of ideal spheres and irregular clumps of different mass proportions are prepared to conduct drained triaxial compression simulations.A well-defined shape descriptor named OR is adopted to quantify particle shape differences of numerical samples at both form and roundness aspects,and the particle sliding friction coefficient varies from 0.001 to 1 to consider the surface roughness effect equivalently in *** stress-strain relationships as well as peak and critical friction angles of these assemblies are examined ***,contact network and anisotropic fabric characteristics within different granular assemblies are analyzed to explore the microscopic origins of the multi-scale shape-dependent shear *** study helps to improve the current understanding with respect to the influence of the particle shape on the shear behavior of sands from different shape aspects.

关键词： Discrete element method(DEM) Overall regularity(OR) Particle sliding friction Peak and critical friction angles Fabric anisotropy Dense sands

Multiple Time Scale Analysis of River Runoff Using Wavelet Transform for Dagujia River Basin, Yantai, China

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Chinese Geographical Science 2009年第2期19卷 158-167页

作者： LIU Delin LILT Xianzhao LI Bicheng zhao shiwei LI Xiguo Research Center of Soil and Water Conservation and Ecological Environment Chinese Academy of Sciences and Ministry of Education Northwest Sci-Tech University of Agriculture and Forestry Yangling 712100 China College of Geography and Resource Management Ludong University Yantai 264025 China Yantai Hydrology and Water Resource Survey Office Yantai 264025 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China

Based on monthly river runoff and meteorological data, a method of Morlet wavelet transform was used to analyze the multiple time scale characteristics of river runoff in the Dagujia River Basin, Yantai City, Shandong Province. The results showed that the total annual river runoffin the Dagujia River Basin decreased significantly from 1966 to 2004, and the rate of decrease was 48× 10^6ma/10yr, which was higher than the mean value of most rivers in China. Multiple time scale characteristics existed, which accounted for different aspects of the changes in annual river runoff, and the major periods of the runofftime series were identified as about 28 years, 14 years and 4 years with decreasing levels of fluctuation. The river runoff evolution process was controlled by changes in precipitation to a certain extent, but it was also greatly influenced by human activities. Also, for different time periods and scales, the impacts of climate changes and human activities on annual river runoff evolution occurred at the same time. Changes in the annual river runoffwere mainly associated with climate change before the 1980s and with human activities after 1981.

关键词： multiple time scale river runoff climate change Morlet wavelet transform Dagujia River

Elman neural network for predicting aero optical imaging deviation based on improved slime mould algorithm

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Optoelectronics Letters 2023年第5期19卷 290-295页

作者： XU Liang WANG Luyang XUE Wei zhao shiwei ZHOU Liye Tianjin Key Laboratory of Complex Control Theory and Application School of Electronic Engineering and AutomationTianjin University of TechnologyTianjin 300384China China Academy of Aerospace Science and Innovation Beijing 100048China

This research suggests a methodology to optimize Elman neural network based on improved slime mould algorithm(ISMA) to anticipate the aero optical imaging *** improved Tent chaotic sequence is added to the SMA to initialize the population to accelerate the algorithm’s speed of ***,an improved random opposition-based learning was added to further enhance the algorithm’s performance in addressing problems that the SMA has such as weak convergence ability in the late iteration and an easy tendency to fall into local optimization in the optimization process when solving the optimization ***,the algorithm model is compared to the Elman neural network and the SMA optimization Elman neural network *** three models are assessed using four evaluation indicators,and the findings demonstrate that the ISMA optimization model can anticipate the aero optical imaging deviation in an accurate way.

关键词： neural Elman network

Analysis of light propagation characteristic in the aero-optic flow field of cone-headed vehicle with side window

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Optoelectronics Letters 2024年第1期20卷 58-64页

作者： XU Liang ZHOU Liye WANG Luyang zhao shiwei WANG Tao Tianjin Key Laboratory of Complex Control Theory and Application School of Electrical Engineering and AutomationTianjin University of TechnologyTianjin 300384China School of Intelligent Engineering Sun Yat-sen UniversityGuangzhou 510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519000China

Aero-optic imaging deviation research is carried out for infrared-guided vehicle with cone-head side window,with a focus on the propagation characteristics of light in an aero-optic flow *** the light entering the aero-optic flow field from the free-stream should be close to the normal,numerous data indicate that the light is refracted away from the *** paper divides the aero-optic flow field into two parts and uses the gas density distribution in the aero-optic flow field to propose the hypothesis that there are two modes of refraction when light propagates through the flow *** results show that light propagates from the optically denser medium to the optically thinner medium after passing through the shock wave and eventually leads to refraction away from the normal when the light enters the aero-optic flow field.

关键词： flow propagation light

Chromosome-scale genome assembly of marigold (Tagetes erecta L.):An ornamental plant and feedstock for industrial lutein production

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Horticultural Plant Journal 2023年第6期9卷 1119-1130页

作者： Haibo Xin Fangfang Ji Jie Wu Shiya Zhang Caijie Yi shiwei zhao Richen Cong Liangjun zhao Hua Zhang zhao Zhang Beijing Key Laboratory of Greening Plants Breeding Beijing Academy of Forestry and Landscape ArchitectureBeijing 100102China Beijing Key Laboratory of Development and Quality Control of Ornamental Crops Department of Ornamental HorticultureChina Agricultural UniversityBeijing 100193China

Marigold(Tagetes erecta L., African marigold) is a widely grown ornamental plant and a main source of the carotenoid lutein for the industrial production of pharmaceuticals, food coloring, and feed additives. To gain a deeper understanding of the genetic mechanism of lutein in marigold, a chromosome-scale assembly of the marigold(T. erecta V-01) genome was completed based on Illumina, PacBio, and Hi-C reads. The707.21-Mb assembled genome consisted of 35 834 annotated protein-coding genes, with 97.7% genomic integrity. We anchored 87.8% of the contigs(covering 621.20 Mb) to 12 pseudochromosomes, bringing the scaffold N50 length to 54.15 Mb. Phylogenetic analysis showed that marigold was closely related to the Asteraceae species bitter vine(Mikania micrantha) and sunflower(Helianthus annuus), all three of which originated in the Americas. Marigold diverged from the sunflower clade 23.57 million years ago(MYA) and from M. micrantha 19.59 *** has undergone three whole-genome duplication events, as well as a recent whole-genome duplication event(WGD-2) common to *** and M. micrantha. Marigold gene families were significantly less expanded than those of M. micrantha or H. annuus, and the marigold genome contained significantly fewer interspersed repeats, which might account for its smaller genome. In addition, a range of candidate genes involved in the lutein biosynthetic pathway were identified. The high-quality reference genome obtained in this study provided a valuable genomic resource for studying the evolution of the Asteraceae family and for improving marigold breeding strategies.

关键词： T.erecta L. Genome Gene family Carotenoid Lutein