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Effects of thinning on the understory light environment of different stands and the photosynthetic performance and growth of the reforestation species Phoebe bournei

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Journal of Forestry Research 2024年第1期35卷 12-28页

作者： Shicheng Su Nianqing Jin xiaoli Wei College of Forestry Guizhou UniversityGuiyang 550025People’s Republic of China Institute for Forest Resources and Environment of Guizhou Guizhou UniversityGuiyang 550025People’s Republic of China

Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the *** this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei *** canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following *** improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light *** the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral *** photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light *** a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal *** a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of *** seedlings,and a reduction increased light absorption and use capacity and height:diameter *** growth advantage transformed from diameter to height,enabling seedlings to access more *** findings suggest that the regeneration of shade-tolerant species such as *** could be enhanced if a targeted approach to thinning based on stand type was adopted.

关键词： Thinning Understory light environment Phoebe bournei Photosynthetic performance Growth performance

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Improved spatio-temporal alignment measurement method for hull deformation

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Journal of Systems Engineering and Electronics 2024年第2期35卷 485-494页

作者： XU Dongsheng YU Yuanjin ZHANG xiaoli PENG Xiafu School of Automation Beijing Institute of TechnologyBeijing 100081China School of Aerospace Engineering Xiamen UniversityXiamen 361005China

In this paper,an improved spatio-temporal alignment measurement method is presented to address the inertial matching measurement of hull deformation under the coexistence of time delay and large misalignment *** misalignment angle and time delay often occur simultaneously and bring great challenges to the accurate measurement of hull deformation in space and *** proposed method utilizes coarse alignment with large misalignment angle and time delay estimation of inertial measurement unit modeling to establish a brand-new spatiotemporal aligned hull deformation measurement *** addition,two-step loop control is designed to ensure the accurate description of dynamic deformation angle and static deformation angle by the time-space alignment method of hull *** experiments illustrate that the proposed method can effectively measure the hull deformation angle when time delay and large misalignment angle coexist.

关键词： inertial measurement spatio-temporal alignment hull deformation

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响应面法优化剪刀股中总皂苷的提取工艺

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中国现代中药 2017年第7期19卷 1021-1025页

作者：王威孙晓丽河北省张家口市第三医院河北张家口075000 河北省易县妇幼保健院河北保定074200

目的:优化剪刀股中总皂苷的超声提取工艺,建立剪刀股中总皂苷的含量测定方法。方法:在单因素试验的基础上,采用Box-Behnken设计,结合响应面分析法,以剪刀股总皂苷的提取率为评价指标,采用分光光度法,测定剪刀股中总皂苷的含量,采用Desig... 详细信息

目的:优化剪刀股中总皂苷的超声提取工艺,建立剪刀股中总皂苷的含量测定方法。方法:在单因素试验的基础上,采用Box-Behnken设计,结合响应面分析法,以剪刀股总皂苷的提取率为评价指标,采用分光光度法,测定剪刀股中总皂苷的含量,采用Design-Expert v8.0.6软件对实验结果进行拟合和建模,确定剪刀股总皂苷超声提取的最佳工艺。结果:超声法提取剪刀股中总皂苷的最佳工艺为乙醇浓度80%,液料比18∶1,温度71℃,超声时间15 min,超声功率2.0 W,在此条件下,剪刀股中总皂苷提取率为1.744%,RSD=0.65%(n=6)。结论:该方法操作简便、准确、灵敏、重复性好,可作为剪刀股总皂苷的提取及含量测定方法。

关键词：剪刀股总皂苷超声提取含量测定响应面法

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Anisotropic tribology and electrification properties of slidingmode triboelectric nanogenerator with groove textures

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Friction 2024年第8期12卷 1828-1837页

作者： Weixu YANG Jieyang WANG xiaoli WANG Ping CHEN Department of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China Department of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China

Sliding-mode triboelectric nanogenerator(S-TENG)is based on the coupling of triboelectrification and electrostatic induction,converting electrical energy from sliding *** micro-textures into the sliding surface,and adjusting the angle between the texture and sliding direction(direction angle)may achieve performance anisotropy,which provides novel ideas for optimizing the tribology and electrification performance of *** guide the performance optimization based on the anisotropy,in this paper,groove micro-textures were fabricated on the surface of S-TENG,and anisotropic tribology and electrification performance were obtained through changing the direction *** on the surface analysis and after-cleaning tests,the mechanism of the anisotropy was *** is shown that the anisotropy of friction coefficient can be attributed to the changes of texture edge induced resistance and groove captured wear debris,while the voltage anisotropy is due to the variations of debris accumulated on the sliding interface and the resulting charge *** the selected 0°–90°direction angles,S-TENG at angle of 90°exhibits relatively small stable friction coefficient and high open-circuit voltage,and thus it is recommended for the performance *** open-circuit voltage is not directly associated with the friction coefficient,but closely related to the wear debris accumulated on the sliding *** study presents a simple and convenient method to optimize the performance of S-TENG,and help understand the correlation between its tribology and electrical performance.

关键词： sliding-mode triboelectric nanogenerator groove textures direction angle performance anisotropy tribology&electrification properties

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Study on the coupling calculation method for the launch dynamics of a self-propelled artillery multibody system considering engraving process

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Defence Technology（防务技术） 2024年第9期39卷 67-85页

作者： Shujun Zhang Xiaoting Rui Hailong Yu xiaoli Dong Institute of Launch Dynamics Nanjing University of Science and TechnologyNanjing 210094China National Key Laboratory of Complex Multibody System Dynamics Nanjing 210094China

The launch dynamics theory for multibody systems emerges as an innovative and efficacious approach for the study of launch dynamics,capable of addressing the challenges of complex modeling,diminished computational efficiency,and imprecise analyses of system dynamic responses found in the dynamics research of intricate multi-rigid-flexible body systems,such as self-propelled *** advancement aims to enhance the firing accuracy and launch safety of self-propelled *** the shortfall of overlooking the band engraving process in existing theories,this study introduces a novel coupling calculation methodology for the launch dynamics of a self-propelled artillery multibody *** method leverages the ABAQUS subroutine interface VUAMP to compute the dynamic response of the projectile and barrel during the launch process of large-caliber self-propelled ***,it examines the changes in projectile resistance and band deformation in relation to projectile motion throughout the band engraving *** analysis of the computational outcomes with experimental data evidences that the proposed method offers a more precise depiction of the launch process of self-propelled artillery,thereby enhancing the accuracy of launch dynamics calculations for self-propelled artillery.

关键词： Self-propelled artillery Engraving process Multibody system dynamics Launch dynamics

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Scale-space effect and scale hybridization in image intelligent recognition of geological discontinuities on rock slopes

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1315-1336页

作者： Mingyang Wang Enzhi Wang xiaoli Liu Congcong Wang State Key Laboratory of Hydro-science and Engineering Tsinghua UniversityBeijing100084China

Geological discontinuity(GD)plays a pivotal role in determining the catastrophic mechanical failure of jointed rock *** and efficient acquisition of GD networks is essential for characterizing and understanding the progressive damage mechanisms of slopes based on monitoring image *** by recent advances in computer vision,deep learning(DL)models have been widely utilized for image-based fracture *** multi-scale characteristics,image resolution and annotation quality of images will cause a scale-space effect(SSE)that makes features indistinguishable from noise,directly affecting the ***,this effect has not received adequate ***,we try to address this gap by collecting slope images at various proportional scales and constructing multi-scale datasets using image processing ***,we quantify the intensity of feature signals using metrics such as peak signal-to-noise ratio(PSNR)and structural similarity(SSIM).Combining these metrics with the scale-space theory,we investigate the influence of the SSE on the differentiation of multi-scale features and the accuracy of *** is found that augmenting the image's detail capacity does not always yield benefits for vision-based recognition *** light of these observations,we propose a scale hybridization approach based on the diffusion mechanism of scale-space *** results show that scale hybridization strengthens the tolerance of multi-scale feature recognition under complex environmental noise interference and significantly enhances the recognition accuracy of *** also facilitates the objective understanding,description and analysis of the rock behavior and stability of slopes from the perspective of image data.

关键词： Image processing Geological discontinuities Deep learning Multi-scale Scale-space theory Scale hybridization

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Machine learning assisted adsorption performance evaluation of biochar on heavy metal

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 29-42页

作者： Qiannan Duan Pengwei Yan Yichen Feng Qianru Wan xiaoli Zhu Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity College of Urban and Environmental SciencesNorthwest UniversityXi’an710127China Department of Environment Science Shaanxi Normal UniversityXi’an710062China

Heavy metals(HMs)represent pervasive and highly toxic environmental pollutants,known for their long latency periods and high toxicity levels,which pose significant challenges for their removal and ***,the removal of heavy metals from the environment is crucial to ensure the water *** materials,known for their intricate pore structures and abundant oxygen-containing functional groups,are frequently harnessed for their effectiveness in mitigating heavy metal ***,conventional tests for optimizing biochar synthesis and assessing their heavy metal adsorption capabilities can be both costly and *** address this challenge,this paper proposes a data-driven machine learning(ML)approach to identify the optimal biochar preparation and adsorption reaction conditions,with the ultimate goal of maximizing their adsorption *** utilizing a data set comprising 476 instances of heavy metal absorption by biochar,seven classical integrated models and one stacking model were trained to rapidly predict the efficiency of heavy metal adsorption by *** predictions were based on diverse physicochemical properties of biochar and the specific adsorption reaction *** results demonstrate that the stacking model,which integrates multiple algorithms,allows for training with fewer samples to achieve higher prediction accuracy and improved generalization ability.

关键词： Machine learning Biochar Heavy metal Adsorption efficiency

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Spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice in multiple dimensions during 1979 to 2.2.

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Acta Oceanologica Sinica 2024年第3期43卷 102-114页

作者： Yu Guo xiaoli Wang He Xu Xiyong Hou CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China Shandong Key Laboratory of Coastal Environmental Processes Yantai 264003China University of Chinese Academy of Sciences Beijing 100049China

Arctic sea ice is broadly regarded as an indicator and amplifier of global climate *** rapid changes in Arctic sea ice have been widely ***,the spatiotemporal changes in the horizontal and vertical dimensions of Arctic sea ice and its asymmetry during the melt and freeze seasons are rarely quantified simultaneously based on multiple sources of the same long time *** this study,the spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice were investigated from both the horizontal and vertical dimensions during 1979–2.2. based on remote sensing and assimilation *** results indicated that Arctic sea ice was declining at a remarkably high rate of–5.4×10^(4) km^(2./a in sea ice area(SIA)and–2.2.cm/a in sea ice thickness(SIT)during 1979 to 2.2.,and the reduction of SIA and SIT was the largest in summer and the smallest in ***,compared with other sub-regions,SIA showed a sharper declining trend in the Barents Sea,Kara Sea,and East Siberian Sea,while SIT presented a larger downward trend in the northern Canadian Archipelago,northern Greenland,and the East Siberian *** to the seasonal trend of sea ice on sub-region scale,the reduction rate of SIA exhibited an apparent spatial heterogeneity among seasons,especially in summer and winter,i.e.,the sub-regions linked to the open ocean exhibited a higher decline rate in winter;however,the other sub-regions blocked by the coastlines presented a greater decline rate in *** SIT,the sub-regions such as the Beaufort Sea,East Siberian Sea,Chukchi Sea,Central Arctic,and Canadian Archipelago always showed a higher downward rate in all ***,a striking freeze-thaw asymmetry of Arctic sea ice was also *** sea ice changes in different dimensions,sea ice over most regions in the Arctic showed an early retreat and rapid advance in the horizontal dimension but late melting and gradual freezing in the vertical *** amount of sea ice me

关键词： Arctic sea ice sea ice area sea ice thickness spatiotemporal variation freeze-thaw asymmetry

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A NEW GLOBAL OPTIMIZATION ALGORITHM FOR MIXED-INTEGER QUADRATICALLY CONSTRAINED QUADRATIC FRACTIONAL PROGRAMMING PROBLEM

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Journal of Computational Mathematics 2024年第3期42卷 784-813页

作者： Bo Zhang Yuelin Gao Xia Liu xiaoli Huang School of Civil and Hydraulic Engineering School of Mathematics and StatisticsNingxia UniversityYinchuan 750021China School of Mathematics and Information Science North Minzu UniversityYinchuan 750021China Ningxia Province Key Laboratory of Intelligent Information and Data Processing Yinchuan 750021China School of Mathematics and Statistics Ningxia UniversityYinchuan 750021China

The mixed-integer quadratically constrained quadratic fractional programming(MIQCQFP)problem often appears in various fields such as engineering practice,management science and network ***,most of the solutions to such problems are often designed for their unique *** paper puts forward a new global optimization algorithm for solving the problem *** first convert the MIQCQFP into an equivalent generalized bilinear fractional programming(EIGBFP)problem with integer ***,we linearly underestimate and linearly overestimate the quadratic functions in the numerator and the denominator respectively,and then give a linear fractional relaxation technique for EIGBFP on the basis of non-negative *** that,combining rectangular adjustment-segmentation technique and midpointsampling strategy with the branch-and-bound procedure,an efficient algorithm for solving MIQCQFP globally is ***,a series of test problems are given to illustrate the effectiveness,feasibility and other performance of this algorithm.

关键词： Global optimization Branch and bound Quadratic fractional programming Mixed integer programming

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2.5-dimension soil seismic response to oblique incident waves based on exact free-field solution

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 216-235页

作者： Yeongbin Yang Zeyang Zhou xiaoli Wang Xiongfei Zhang Zhilu Wang School of Civil Engineering Chongqing UniversityChongqing 400045China School of Civil Engineering and Architecture Chongqing University of Science and TechnologyChongqing 401331China

With the three dimensional(3D)oblique incident waves exactly determined for the free field,the soil seismic responses in both frequency and time domains are studied by the 2.5 dimension(2.5D)finite/infinite element ***,the free-field responses in frequency domain are solved exactly for 3D arbitrary incident P and SV waves,which requires no coordinate conversion or extra effort for SV waves with super-critical incident ***,the earthquake spectra are incorporated by the concept of equivalent seismic forces on the near-field boundary,based only on the displacements input derived for unit ground accelerations of each frequency using the 2.5D *** the asymmetric 2.5D finite/infinite element model adopted,the procedure for soil seismic analysis is *** solutions computed by the proposed method are verified against those of Wolf’s and de Barros and Luco’s and for inversely calculated ground *** interest is that abrupt variation in soil response occurs around the critical angle on the wave propagation plane for SV *** addition,the horizontal displacements attenuate with increasing horizontal incident angle,while the longitudinal ones increase inversely for 3D incident P and SV waves.

关键词： 3D oblique incident wave seismic response analysis 2.5D approach infinite element half-space

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