检索结果-南通市图书馆

Elevational distribution of forests and its spatiotemporal dynamics in subtropical China from 2000 to 2019

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第8期67卷 2563-2582页

作者： Zhencan ZHENG Liuwen ZHUANG Guofang MIAO Han LIU Zhiqiang CHENG Wenyu LI Rong SHANG Peng GONG Jing Ming CHEN Institute of Geography Fujian Normal University Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education) Fujian Normal University School of Geographical Sciences Fujian Normal University National land Consolidation Center Ministry of Natural Resources Key Laboratory of land Consolidation and Rehabilitation Ministry of Natural Resources Key Laboratory of Digital Mapping and land Information Application Ministry of Natural Resources department of Geography & Planning University of Toronto department of Geography The University of Hong Kong

The subtropical region of China possesses abundant forest resources and features a mountainous *** the implementation of policies such as natural forest protection,the Grain for Green Project,and other initiatives since the beginning of the 21st century,coupled with climate change,the forest resources in this region have undergone significant changes compared to historical *** addition,forest resources distributing mainly in mountainous areas also implies that these changes may vary significantly with *** explore the spatiotemporal dynamics of forest distribution in subtropical China since 2000,especially the trend of changes with elevation,we analyzed the data from two land cover products focusing on forest cover and forest *** used a hierarchical approach,in which coarse-classification forest cover data with relatively small uncertainties impose constraints on forest type data with larger uncertainties,to achieve a reasonable balance between obtaining more details and reducing data *** first divided the forest cover data into‘unchanged'and‘changed'*** the constraints by the forest cover results,we further analyzed the‘unchanged'and‘changed'forest *** results indicated that,since the implementation of ecological engineering and management policies,54%of the area in the subtropical region had maintained unchanged forest cover attributes over the past 20 years,which implied the good state of ecological *** results also showed that dynamic conversions existed in the long term between forests and lands for essential production needs like *** elevational variations of forest cover suggested that the dominant changes came from the conversion between forests and croplands in low-elevation regions below 700 m,the conversion between forests and shrublands in mid-elevation regions of 700–1500 m,and the conversion between forests and grasslands in high-elevation regions above 2000 *** the regio

关键词： Subtropical China land cover Forest cover Forest type Elevational distribution

同方期刊数据库

The effect of topographic density variations on the geoid and orthometric heights in Hong Kong

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2024年第5期 495-503页

作者： Albertini Nsiah Ababio department of land Surveying and Geo-Informatics Hong Kong Polytechnic University

Utilizing the adopted average topographic density of 2670 kg/m3in the reduction of gravity anomalies introduces errors attributed to topographic density variations, which consequently affect geoid modeling accuracy. Furthermore, the mean gravity along the plumbline within the topography in the definition of Helmert orthometric heights is computed approximately by applying the Poincar e-Prey gravity reduction where the topographic density variations are disregarded. The Helmert orthometric heights of benchmarks are then affected by errors. These errors could be random or systematic depending on the specific geological setting of the region where the leveling network is physically established and/or the geoid model is determined. An example of systematic errors in orthometric heights can be given for large regions characterized by sediment or volcanic deposits, the density of which is substantially lower than the adopted topographic density used in Helmert's definition of heights. The same applies to geoid modeling errors. In this study, we investigate these errors in the Hong Kong territory, where topographic density is about 20% lower than the density of 2670 kg/m3. We use the digital rock density model to estimate the effect of topographic density variations on the geoid and orthometric heights. Our results show that this effect on the geoid and Helmert orthometric heights reach maxima of about 2.1 and 0.5 cm, respectively. Both results provide clear evidence that rock density models are essential in physical geodesy applications involving gravimetric geoid modeling and orthometric height determination despite some criticism that could be raised regarding the reliability of these density models. However, in regions dominated by sedimentary and igneous rocks, the geological information is essential in these applications because topographic densities are substantially lower than the average density of 2670 kg/m3, thus introducing large systematic errors in geoid and

关键词：

Dewatering of Scenedesmus obliquus Cultivation Substrate with Microfiltration:Potential and Challenges for Water Reuse and Effective Harvesting

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Engineering 2024年第7期38卷 155-163页

作者： Marco Malaguti Lorenzo Craveri Francesco Ricceri Vincenzo Riggio Mariachiara Zanetti Alberto Tiraferri department of Environment Land and Infrastructure EngineeringPolitecnico di TorinoTorino 10129Italy Clean Water Center Politecnico di TorinoTorino 10129Italy

In the microalgae harvesting process,which includes a step for dewatering the algal suspension,directly reusing extracted water in situ would decrease the freshwater footprint of cultivation *** various algae harvesting techniques,membrane-based filtration has shown numerous *** study evaluated the reuse of permeate streams derived from Scenedesmus obliquus(***)biomass filtration under bench-scale and pilot-scale *** particular,this study identified a series of challenges and mechanisms that influence the water reuse potential and the robustness of the membrane harvesting *** a preliminary phase of this investigation,the health status of the initial biomass was found to have important implications for the harvesting performance and quality of the permeate stream to be reused;healthy biomass ensured better dewatering performance(i.e.,higher water fluxes)and higher quality of the permeate water streams.A series of bench-scale filtration experiments with different combinations of cross-flow velocity and pressure values were performed to identify the operative conditions that would maximize water *** selected conditions,2.4 m·s^(-1)and 1.4 bar(1 bar=105 Pa),respectively,were then applied to drive pilot-scale microfiltration tests to reuse the collected permeate as a new cultivation medium for *** growth in a pilot-scale *** investigation revealed key differences between the behavior of the membrane systems at the two scales(bench and pilot).It indicated the potential for beneficial reuse of the permeate stream as the pilot-scale experiments ensured high harvesting performance and growth rates of biomass in permeate water that were highly similar to those recorded in the ideal cultivation ***,different nutrient reintegration protocols were investigated,revealing that both macro-and micro-nutrient levels are critical for the success of the reuse approach.

关键词： Scenedesmus obliquus Microfiltration Permeate reuse Harvesting Microalgae Pilot-scale

Hybrid pedestrian positioning system using wearable inertial sensors and ultrasonic ranging

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第3期33卷 327-338页

作者： Lin Qi Yu Liu Chuanshun Gao Tao Feng Yue Yu School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China department of land Surveying and Geo-Informatics The Hong Kong Polytechnic UniversityHong Kong 999077China

Pedestrian positioning system(PPS)using wearable inertial sensors has wide applications towards various emerging fields such as smart healthcare,emergency rescue,soldier positioning,*** performance of traditional PPS is limited by the cumulative error of inertial sensors,complex motion modes of pedestrians,and the low robustness of the multi-sensor collaboration *** paper presents a hybrid pedestrian positioning system using the combination of wearable inertial sensors and ultrasonic ranging(H-PPS).A robust two nodes integration structure is developed to adaptively combine the motion data acquired from the single waist-mounted and foot-mounted node,and enhanced by a novel ellipsoid constraint *** addition,a deep-learning-based walking speed estimator is proposed by considering all the motion features provided by different nodes,which effectively reduces the cumulative error originating from inertial ***,a comprehensive data and model dual-driven model is presented to effectively combine the motion data provided by different sensor nodes and walking speed estimator,and multi-level constraints are extracted to further improve the performance of the overall *** results indicate that the proposed H-PPS significantly improves the performance of the single PPS and outperforms existing algorithms in accuracy index under complex indoor scenarios.

关键词： Pedestrian positioning system Wearable inertial sensors Ultrasonic ranging Deep-learning Data and model dual-driven

44％of steep slope cropland in Europe vulnerable to drought

在线全文

学校读者我要写书评

暂无评论

Sliding behaviors of the trapezoidal roof rock block under a lateral dynamic disturbance

地理学与可持续性（英文） 2024年第1期5卷 89-95页

作者： Wendi Wang Eugenio Straffelini Paolo Tarolli department of land EnvironmentAgriculture and ForestryUniversity of PadovaAgripolisViale dell'Università 16LegnaroPD 35020Italy

Steep-slope cropland plays a vital role in food production,economic development,ecosystem diversity,and Eu-ropean cultural ***,these systems are susceptible to extreme weather *** 2022 summer drought significantly impacted European agriculture,but the specific effects on steep-slope crops remain *** this is essential for comprehending similar future events and for implementing effective water management strategies to ensure the sustainability of steep-slope agriculture and associated ecosystem *** study quantitatively analyzes the spatial distribution of twelve major European steep-slope(＞12％)crops and assesses agricultural drought severity during the 2022 events using open-access spatial *** satellite-based Vegetation Health Index(VHI)is utilized to identify critical *** show that olive grove is the most widespread crop in steep slope agriculture(34％of total area),followed by wheat(24％),maize(16％),and vineyard(11％).Almost half of the steep-slope agriculture in Europe suffered drought during summer *** were hardest affected at 79％,primarily in northern Portugal,northern Spain,southern France,and central *** followed at 62％,mainly in Spain,central Italy,southern France,and northern *** groves ranked third at 59％,with the most impact in northern Portugal,southern and central Spain,and southern *** was also significantly affected at 54％.In this paper,we therefore highlight the need to increase steep-slope agriculture resilience by improving water management and promoting sustainable land practices.

关键词： Drought Steep slope cropland Europe Sustainability

来源：评论

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 741-760页

作者： Feng Dai Wancheng Zhu Min Ren Shunchuan Wu Leilei Niu Faculty of land Resources Engineering Kunming University of Science and TechnologyKunming650093China Center for Rock Instability and Seismicity Research Department of Mining EngineeringSchool of Resource and Civil EngineeringNortheastern UniversityShenyang110819China

The surrounding rock of underground space is always affected by external dynamic disturbance from the side position,such as blasting vibration from a stope at the same level or seismic waves from adjacent strata.A series of laboratory tests,numerical simulations and theoretical analyses were carried out in this study to disclose the sliding mechanism of roof rock blocks under lateral ***,the experiments on trapezoidal key block under various clamping loads and disturbance were conducted,followed by numerical simulations using the fast Lagrangian analysis of continua(FLAC3D).Then,based on the conventional wave propagation model and the classical shear-slip constitutive model,a theoretical model was proposed to capture the relative displacement between blocks and the sliding displacement of the key *** results indicate that the sliding displacement of the key block increased linearly with the disturbance energy and decreased exponentially with the clamping load when the key block was disturbed to slide(without instability).Meanwhile,when the key block was disturbed to fall,two types of instability process may appear as immediate type or delayed *** addition,the propagation of stress waves in the block system exhibited obvious low-velocity and lowfrequency characteristics,resulting in the friction reduction effect appearing at the contact interface,which is the essential reason for the sliding of rock *** results can be applied to practical underground engineering and provide valuable guidance for the early detection and prevention of rockfalling disasters.

关键词： Lateral dynamic disturbance Trapezoidal rock block system Low-velocity and low-frequency wave Friction reduction effect Instability mode

Arbuscular mycorrhizal fungi regulate plant mineral nutrient uptake and partitioning in iron ore tailings undergoing eco-engineered pedogenesis

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2024年第2期34卷 385-398页

作者： Zhen LI Songlin WU Yunjia LIU Qing YI Merinda HALL Narottam SAHA Junjian WANG Yuanfang HUANG Longbin HUANG College of land Science and Technology China Agricultural UniversityBeijing 100193China Centre for Mined land Rehabilitation Sustainable Minerals InstituteThe University of QueenslandBrisbaneQLD 4072Australia Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control School of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Excess available K and Fe in Fe ore tailings with organic matter amendment and water-deficiencies may restrain plant colonization and growth,which hinders the formation of eco-engineered soil from these tailings for sustainable and cost-effective mine site *** mycorrhizal(AM)fungi are widely demonstrated to assist plant growth under various unfavorable ***,it is still unclear whether AM symbiosis in tailings amended with different types of plant biomass and under different water conditions could overcome the surplus K and Fe stress for plants in Fe ore tailings,and if so,by what ***,host plants(Sorghum *** ***),either colonized or noncolonized by the AM fungi(Glomus spp.),were cultivated in lucerne hay(LH,C:N ratio of 18)-or sugarcane mulch(SM,C:N ratio of 78)-amended Fe ore tailings under well-watered(55%water-holding capacity(WHC)of tailings)or water-deficient(30%WHC of tailings)*** mycorrhizal colonization,plant growth,and mineral elemental uptake and partitioning were *** indicated that AM fungal colonization improved plant growth in tailings amended with plant biomass under water-deficient *** mycorrhizal fungal colonization enhanced plant mineral element uptake,especially P,both in the LH-and SM-amended tailings regardless of water ***,AM symbiosis development restrained the translocation of excess elements(i.e.,K and Fe)from plant roots to shoots,thereby relieving their *** AM fungal roles in P uptake and excess elemental partitioning were greater in LH-amended tailings than in SM-amended *** deficiency weakened AM fungal colonization and functions in terms of mineral element uptake and *** findings highlighted the vital role AM fungi played in regulating plant growth and nutrition status in Fe ore tailings technosol,providing an important basis for involvement of AM fungi in the eco-engineered pedo

关键词： Fe stress fungal symbiosis K stress mine site rehabilitation mycorrhizal colonization plant biomass amendment plant nutrition water deficiency

Intelligent speed adaptation for visibility technology affects drivers’speed selection along curves with sight limitations

在线全文

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2024年第1期11卷 16-27页

作者： Abrar Hazoor Alberto Terrafino Leandro L.Di Stasi Marco Bassani department of Environment Landand Infrastructure EngineeringPolitecnico di TorinoTorino 10129Italy Road Traffic Division Nord UniversityStjørdal 7502Norway Mind Brainand Behavior Research Centre(CIMCYC)University of GranadaGranada 18071Spain

Sight obstructions along road curves can lead to a crash if the driver is not able to stop the vehicle in *** is a particular issue along curves with limited available sight,where speed management is necessary to avoid unsafe situations(e.g.,driving off the road or invading the other traffic lane).To solve this issue,we proposed a novel intelligent speed adaptation(ISA)system for visibility,called V-ISA(intelligent speed adaptation for visibility).It estimates the real-time safe speed limits based on the prevailing sight conditions.V-ISA comes with three variants with specific feedback modalities(1)visual and(2)auditory information,and(3)direct intervention to assume control over the vehicle ***,we investigated the efficiency of each of the three V-ISA variants on driving speed choice and lateral behavioural response along road curves with limited and unsafe available sight distances,using a driving *** also considered curve road geometry(curve direction:rightward ***).Sixty active drivers were recruited for the *** half of them(experimental group)tested the three V-ISA variants(and a V-ISA off condition),the other half always drove with the V-ISA off(validation group).We used a linear mixed-effect model to evaluate the influence of V-ISA on driver *** V-ISA variants were efficient at reducing speeds at entrance points,with no discernible negative impact on driver lateral *** rightward curves,the V-ISA intervening variant appeared to be the most effective at adapting to sight *** of the current study implies that V-ISA might assist drivers to adjust their operating speed as per prevailing sight conditions and,consequently,establishes safer driving conditions.

关键词： Sight distance Intelligent speed adaptation Driver behaviour Road safety Driving simulation Advanced driver assistance systems

Quantifying the agreement and accuracy characteristics of four satellite-based LULC products for cropland classification in China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2024年第1期23卷 283-297页

作者： Jie Xue Xianglin Zhang Songchao Chen Bifeng Hu Nan Wang Zhou Shi department of land Management Zhejiang UniversityHangzhou 310058China Institute of Applied Remote Sensing and Information Technology College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang UniversityHangzhou 311215China department of land Resource Management School of Public Finance and Public AdministrationJiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Data Science in Finance and Economics Jiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Spectroscopy Sensing Ministry of Agriculture and Rural AffairsHangzhou 310058China

Various land use and land cover(LULC)products have been produced over the past decade with the development of remote sensing *** the differences in LULC classification schemes,there is a lack of research on assessing the accuracy of their application to croplands in a unified ***,this study evaluated the spatial and area accuracies of cropland classification for four commonly used global LULC products(i.e.,MCD12Q1V6,GlobCover2009,FROM-GLC and Globeland30)based on the harmonised FAO criterion,and quantified the relationships between four factors(i.e.,slope,elevation,field size and crop system)and cropland classification *** validation results indicated that MCD12Q1 and Globeland30 performed well in cropland classification regarding spatial consistency,with overall accuracies of 94.90 and 93.52%,*** FROMGLC showed the worst performance,with an overall accuracy of 83.17%.Overlaying the cropland generated by the four global LULC products,we found the proportions of complete agreement and disagreement were 15.51 and 44.72% for the cropland classification,*** consistency was mainly observed in the Northeast China Plain,the Huang-Huai-Hai Plain and the northern part of the Middle-lower Yangtze Plain,*** contrast,low consistency was detected primarily on the eastern edge of the northern and semiarid region,the Yunnan-Guizhou Plateau and southern *** size was the most important factor for mapping *** area accuracy,compared with China Statistical Yearbook data at the provincial scale,the accuracies of different products in descending order were:Globeland30,FROM-GLC,MCD12Q1,and *** cropland classification schemes mainly caused large area deviations among the four products,and they also resulted in the different ranks of spatial accuracy and area accuracy among the four *** results can provide valuable suggestions for selecting cropland products at the national or provinc

关键词： global LULC products cropland mapping accuracy evaluation food security China