期刊文献+
共找到78,848篇文章
< 1 2 250 >
每页显示 20 50 100
Stress triggering effect on the 2022 Honghe M_(S)5.0 earthquake with historical strong earthquakes
1
作者 Mingce Wang Zifeng Liu Ruijie Luo 《Geodesy and Geodynamics》 EI CSCD 2024年第2期107-113,共7页
The 2022 Honghe M_(S)5.0 seismic event is intriguing due to its occurrence in the south of the Red River Fault,an area historically lacking seismic activities greater than M_(S)5.0.To elucidate the seismogenic mechani... The 2022 Honghe M_(S)5.0 seismic event is intriguing due to its occurrence in the south of the Red River Fault,an area historically lacking seismic activities greater than M_(S)5.0.To elucidate the seismogenic mechanism and scrutinize stress-triggered interactions,we calculated co-seismic and post-seismic Coulomb stress alterations induced by nine historical seismic events(M≥6.0).The analysis reveals that these substantial seismic events provoked co-seismic stress augmentations of 1.409 bar and postseismic stress increments of 0.159 bar.Noteworthy seismic events,such as the 1833 Songming,1877Shiping,1913 Eshan,and 1970 Tonghai earthquakes,catalyzed the occurrence of the Honghe earthquake.Areas of heightened future seismic risk include the southern region of the Red River Fault and the eastern segments of the Shiping-Jianshui and Qujiang faults.Additionally,we assessed the correlation between the spatial distribution of aftershocks and the Coulomb stress shift triggered by the mainshock,taking into account the influence of calculation parameter settings. 展开更多
关键词 Honghe Ms5.0 earthquake Coulomb failurestress Stress triggering historical strongearthquakes
原文传递
The Implementation of Ray Tracing Algorithm with OpenMP Parallelization
2
作者 Noor Alnasser Raghad Alabssi +2 位作者 Batool Faran Latifah Alessa Naya Nagy 《Journal of Computer and Communications》 2024年第1期120-130,共11页
Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calcula... Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calculation of lighting and reflecting impact [2]. As ray tracing is a time-consuming process, the need for parallelization to solve this problem arises. One downside of this solution is the existence of race conditions. In this work, we explore and experiment with a different, well-known solution for this race condition. Starting with the introduction and the background section, a brief overview of the topic is followed by a detailed part of how the race conditions may occur in the case of the ray tracing algorithm. Continuing with the methods and results section, we have used OpenMP to parallelize the Ray tracing algorithm with the different compiler directives critical, atomic, and first-private. Hence, it concluded that both critical and atomic are not efficient solutions to produce a good-quality picture, but first-private succeeded in producing a high-quality picture. 展开更多
关键词 PARALLELIZATION Ray tracing Parallel Computer Architecture OPENMP
下载PDF
Heritage Communities in Consumer Contexts Spatial Production of Tourism Research-Take Qixian Zhao Yu Historical City as an Example
3
作者 BAI Zhao-yi ZHU Jun-jie WEN Jia-hao 《Journal of Literature and Art Studies》 2024年第1期95-108,共14页
Taking Zhaoyu Historical City in Qixian County as an example,this paper explores the production process of tourism space in Zhaoyu Historical City in the context of consumption,based on Lefebvre's triadic dialecti... Taking Zhaoyu Historical City in Qixian County as an example,this paper explores the production process of tourism space in Zhaoyu Historical City in the context of consumption,based on Lefebvre's triadic dialectic theory.The study reveals that,driven by the development of tourism,subjects such as the government and planners possess absolute dominance over spatial representations,while residents demonstrate receptive and adaptive action strategies and social relations are reproduced,presenting a harmonious state.Further exploring the tourism community in the environmental performance of the subject of action,social relations,consumption demand,daily life practice,cultural capital,etc.,the daily life practice of the tourism community has transcended the original logic of tourism spatial production and has a certain extension.The mechanism analysis in this paper can help guide the healthy development of tourism space in the neighboring historical cities or communities and achieve the dual purpose of promoting the economic development of the community and heritage protection. 展开更多
关键词 spatial production theory tourism space consumption context heritage community ZhaoYu historical City
下载PDF
基于chirplet path tracing-VMD的变转速信号故障特征提取
4
作者 周福成 白怡凡 +2 位作者 付滋翔 何玉灵 唐贵基 《国外电子测量技术》 北大核心 2023年第9期193-198,共6页
针对变分模态分解方法在提取故障特征时处理非平稳信号能力不足的情况,提出基于线调频小波路径追踪(chirplet path tracing)的自适应改进变分模态分解(variational mode decomposition,VMD)方法。该方法首先利用线调频小波路径追踪算法... 针对变分模态分解方法在提取故障特征时处理非平稳信号能力不足的情况,提出基于线调频小波路径追踪(chirplet path tracing)的自适应改进变分模态分解(variational mode decomposition,VMD)方法。该方法首先利用线调频小波路径追踪算法由非平稳信号得到估计转速变化曲线;其次对目标信号进行等角度重采样,通过转速变化曲线将信号从时域转化为角域;再次采用奇异值分解确定角域信号的降噪阶次,当该阶次自适应变分模态分解的分量个数后,对重采样信号进行变分模态分解处理;最后对分解后的各信号分量进行Hilbert包络谱分析,从而提取故障特征。通过对齿轮箱轴承故障进行仿真和实验验证,表明该方法能有效提取变转速信号的故障特征。 展开更多
关键词 线调频小波路径追踪 变分模态分解 变转速信号 故障特征提取
原文传递
A rabies virus-based toolkit for efficient retrograde labeling and monosynaptic tracing 被引量:1
5
作者 Kun-Zhang Lin Lei Li +5 位作者 Wen-Yu Ma Xin Yang Zeng-Peng Han Neng-Song Luo Jie Wang Fu-Qiang Xu 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第8期1827-1833,共7页
Analyzing the structure and function of the brain's neural network is critical for identifying the working principles of the brain and the mechanisms of brain diseases.Recombinant rabies viral vectors allow for th... Analyzing the structure and function of the brain's neural network is critical for identifying the working principles of the brain and the mechanisms of brain diseases.Recombinant rabies viral vectors allow for the retrograde labeling of projection neurons and cell type-specific trans-monosynaptic tracing,making these vectors powerful candidates for the dissection of synaptic inputs.Although several attenuated rabies viral vectors have been developed,their application in studies of functional networks is hindered by the long preparation cycle and low yield of these vectors.To overcome these limitations,we developed an improved production system for the rapid rescue and preparation of a high-titer CVS-N2c-ΔG virus.Our results showed that the new CVS-N2c-ΔG-based toolkit performed remarkably:(1)N2cG-coated CVS-N2c-ΔG allowed for efficient retrograde access to projection neurons that were unaddressed by rAAV9-Retro,and the efficiency was six times higher than that of rAAV9-Retro;(2)the trans-monosynaptic efficiency of oG-mediated CVS-N2c-ΔG was 2–3 times higher than that of oG-mediated SAD-B19-ΔG;(3)CVS-N2c-ΔG could delivery modified genes for neural activity monitoring,and the time window during which this was maintained was 3 weeks;and(4)CVS-N2c-ΔG could express sufficient recombinases for efficient transgene recombination.These findings demonstrate that new CVS-N2c-ΔG-based toolkit may serve as a versatile tool for structural and functional studies of neural circuits. 展开更多
关键词 functional studies neural activity neural circuits projection neurons rAAV9-Retro rabies virus recombination retrograde labeling synaptic inputs trans-monosynaptic tracing
下载PDF
Graph CA: Learning From Graph Counterfactual Augmentation for Knowledge Tracing
6
作者 Xinhua Wang Shasha Zhao +3 位作者 Lei Guo Lei Zhu Chaoran Cui Liancheng Xu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第11期2108-2123,共16页
With the popularity of online learning in educational settings, knowledge tracing(KT) plays an increasingly significant role. The task of KT is to help students learn more effectively by predicting their next mastery ... With the popularity of online learning in educational settings, knowledge tracing(KT) plays an increasingly significant role. The task of KT is to help students learn more effectively by predicting their next mastery of knowledge based on their historical exercise sequences. Nowadays, many related works have emerged in this field, such as Bayesian knowledge tracing and deep knowledge tracing methods. Despite the progress that has been made in KT, existing techniques still have the following limitations: 1) Previous studies address KT by only exploring the observational sparsity data distribution, and the counterfactual data distribution has been largely ignored. 2) Current works designed for KT only consider either the entity relationships between questions and concepts, or the relations between two concepts, and none of them investigates the relations among students, questions, and concepts, simultaneously, leading to inaccurate student modeling. To address the above limitations,we propose a graph counterfactual augmentation method for knowledge tracing. Concretely, to consider the multiple relationships among different entities, we first uniform students, questions, and concepts in graphs, and then leverage a heterogeneous graph convolutional network to conduct representation learning.To model the counterfactual world, we conduct counterfactual transformations on students’ learning graphs by changing the corresponding treatments and then exploit the counterfactual outcomes in a contrastive learning framework. We conduct extensive experiments on three real-world datasets, and the experimental results demonstrate the superiority of our proposed Graph CA method compared with several state-of-the-art baselines. 展开更多
关键词 Contrastive learning counterfactual representation graph neural network knowledge tracing
下载PDF
The Arctic Sea Ice Thickness Change in CMIP6’s Historical Simulations
7
作者 Lanying CHEN Renhao WU +3 位作者 Qi SHU Chao MIN Qinghua YANG Bo HAN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2023年第12期2331-2343,共13页
This study assesses sea ice thickness(SIT)from the historical run of the Coupled Model Inter-comparison Project Phase 6(CMIP6).The SIT reanalysis from the Pan-Arctic Ice Ocean Modeling and Assimilation System(PIOMAS)p... This study assesses sea ice thickness(SIT)from the historical run of the Coupled Model Inter-comparison Project Phase 6(CMIP6).The SIT reanalysis from the Pan-Arctic Ice Ocean Modeling and Assimilation System(PIOMAS)product is chosen as the validation reference data.Results show that most models can adequately reproduce the climatological mean,seasonal cycle,and long-term trend of Arctic Ocean SIT during 1979-2014,but significant inter-model spread exists.Differences in simulated SIT patterns among the CMIP6 models may be related to model resolution and sea ice model components.By comparing the climatological mean and trend for SIT among all models,the Arctic SIT change in different seas during 1979-2014 is evaluated.Under the scenario of historical radiative forcing,the Arctic SIT will probably exponentially decay at-18%(10 yr)-1 and plausibly reach its minimum(equilibrium)of 0.47 m since the 2070s. 展开更多
关键词 sea ice thickness Arctic Ocean climate change historical simulation CMIP6
下载PDF
Impacts of anisotropy coefficient and porosity on the thermal conductivity and P-wave velocity of calcarenites used as building materials of historical monuments in Morocco
8
作者 Abdelaali Rahmouni Abderrahim Boulanouar +6 位作者 Younes El Rhaffari Mohammed Hraita Aziz Zaroual Yves Géraud Jamal Sebbani Abdellah Rezzouk Bassem S.Nabawy 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第7期1687-1699,共13页
It is essential to study the porosity,thermal conductivity,and P-wave velocity of calcarenites,as well as the anisotropy coefficients of the thermal conductivity and P-wave velocity,for civil engineering,and conservat... It is essential to study the porosity,thermal conductivity,and P-wave velocity of calcarenites,as well as the anisotropy coefficients of the thermal conductivity and P-wave velocity,for civil engineering,and conservation and restoration of historical monuments.This study focuses on measuring the thermal conductivity using the thermal conductivity scanning(TCS)technique and measuring the P-wave ve-locity using portable equipment.This was applied for some dry and saturated calcarenite samples in the horizontal and vertical directions(parallel and perpendicular to the bedding plane,respectively).The calcarenites were selected from some historical monuments in Morocco.These physical properties were measured in the laboratory to find a reliable relationship between all of these properties.As a result of the statistical analysis of the obtained data,excellent linear relationships were observed between the porosity and both the thermal conductivity and porosity.These relationships are characterized by relatively high coefficients of determination for the horizontal and vertical samples.Based on the thermal conductivity and P-wave velocity values in these two directions,the anisotropy coefficients of these two properties were calculated.The internal structure and the pore fabric of the calcarenite samples were delineated using scanning electron microscopy(SEM),while their chemical and mineral compositions were studied using the energy dispersive X-ray analysis(EDXA)and X-ray diffraction(XRD)techniques. 展开更多
关键词 Moroccan historical monuments Calcarenite Thermal conductivity P-wave velocity POROSITY Anisotropy coefficient Water saturation
下载PDF
Legacy effects of historical woodland changes on contemporary plant functional composition
9
作者 Ji-Zhong Wan Chun-Jing Wang 《Forest Ecosystems》 SCIE CSCD 2023年第5期569-578,共10页
Considering the legacy of plant functional composition can help assess ecosystem functions and ecosystem services across different spatial scales under land cover changes.Woody plants likely respond to natural and ant... Considering the legacy of plant functional composition can help assess ecosystem functions and ecosystem services across different spatial scales under land cover changes.Woody plants likely respond to natural and anthropogenic perturbations due to historical events(e.g.,agricultural development),thus contemporary plant functional composition may be explained by historical woodland change,a type of land cover change.We propose that historical woodland changes may have legacy effects on contemporary plant functional composition.Here,we used partial least squares regression and linear mixed model analyses to test this assumption by coupling data on community weighted means(CWM)and community weighted variance(CWV)of vegetation plots and calculating the time of woodland existence across different periods from AD 0 to 2017.We found that the legacy effects of historical land cover changes on CWM and CWV during the existence time of woodland,particularly from AD 0 to 900,were drivers of contemporary plant functional composition at large spatial scales.Furthermore,historical woodland changes can affect contemporary plant functional composition,depending on the biome type.Particularly,the CWM of plant height,seed mass,and seed length showed the strongest correlations with woodland changes from AD 1910 to 2010 in tropics with year-round rain,and the CWM of leaf traits correlated with woodland changes from AD 0 to 1700 in tropics with summer rain.Our study provides the effective evidence on the legacy of historical woodland changes and the effects on contemporary plant functional composition,which is crucial with respect to effective management of plant diversity and assessing ecosystem functions and services from local to global scales over time. 展开更多
关键词 BIOME Community weighted means Global scale historical woodland Land cover Plant functional trait
下载PDF
Protective Renovation of the Historical Environment of Traffic Cultural Heritage:Necessity and Feasibility
10
作者 DONG Lili LI Yueyan 《Journal of Landscape Research》 2023年第1期79-84,共6页
Starting from the reality of protective renovation of the historical environment of traffic cultural heritage,this paper discusses its necessity from the role and value of protective renovation of historical environme... Starting from the reality of protective renovation of the historical environment of traffic cultural heritage,this paper discusses its necessity from the role and value of protective renovation of historical environment on overall protection of traffic cultural heritage and contemporary value exploration.By analyzing the current research status of traffic history,protection theories and methods of historical environment,cultural routes,linear cultural landscape and heritage corridors and other theoretical methods,as well as the effectiveness of digital protection and other technical approaches,this paper demonstrates the theoretical basis and feasible technical approaches for protective renovation of the historical environment of traffic cultural heritage.Moreover,it is suggested to construct the historical environment evaluation system of traffic cultural heritage and form a systematic design process of protective renovation. 展开更多
关键词 Traffic cultural heritage historical environmental protection Renewal design Linear cultural landscape historical geographic information system
下载PDF
Distinguishing the main components of submarine groundwater and estimating the corresponding fluxes based on radium tracing method—taking the Maowei Sea for example
11
作者 Linwei Li Jinzhou Du +1 位作者 Xilong Wang Yanling Lao 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第8期1-23,共23页
Submarine groundwater discharge(SGD)is an important part in the land-sea interactions,which mainly contains three components:submarine fresh groundwater discharge(SFGD),tidal flat recirculated saline groundwater disch... Submarine groundwater discharge(SGD)is an important part in the land-sea interactions,which mainly contains three components:submarine fresh groundwater discharge(SFGD),tidal flat recirculated saline groundwater discharge(tidal flat RSGD)and subtidal recirculated saline groundwater discharge(subtidal RSGD).In order to make a more accurate assessment of the impact of SGD on coastal ecological environment,it is necessary to distinguish the main components of SGD.In this study,the Maowei Sea,located in the northern part of the Beibu Gulf,was selected as the study area.Based on the radium(Ra)tracing method,we present a new analytical method for distinguishing the three main components of SGD in this area combined with field data.The average daily flow along the coastline of the Maowei Sea of tidal flat RSGD was slightly higher than that of SFGD,and both two were on the magnitude of 1×10^(5)m^(3)/d.The average daily flow for the subtidal RSGD of the entire subtidal zone of the Maowei Sea reached to the magnitude of 1×10^(6)-1×10^(7)m^(3)/d.The long-term variation trend of terrestrial SGD is a valuable information for the study of the influence of terrigenous material on the coastal ecological environment.Based on the results of four sampling periods,it is found that the fluxes of SFGD and tidal flat RSGD in the Maowei Sea had good linear correlation with the net precipitation.As an example,January 2015 to August 2022 were selected as the study periods,and the variation trends of SFGD and tidal flat RSGD were calculated by linear function with net precipitation as the independent variable.The results showed that the flux of tidal flat RSGD was slightly higher than that of SFGD,and the difference between the two is larger in flood season while smaller in dry season.In general,in the coastal range of China,the total SGD flux in the Maowei Sea area is at a high level,and the SFGD flux is at a medium level. 展开更多
关键词 submarine groundwater discharge bottom sediment radium tracing method offshore transport long-term monitoring
下载PDF
Establishment and Error Analysis of Model of Interference Fringe Contrast for Laser Tracing Measurement Optical System
12
作者 Hongfang Chen Mengyang Sun +3 位作者 Yinglun Ma Liang Tang Yu Wang Huixu Song 《Journal of Harbin Institute of Technology(New Series)》 CAS 2023年第4期37-49,共13页
A method was proposed to analyze the influences of the non-ideal spectroscopic performance of optical components and orientation errors of a laser tracing measurement optical system on the tracing measurement performa... A method was proposed to analyze the influences of the non-ideal spectroscopic performance of optical components and orientation errors of a laser tracing measurement optical system on the tracing measurement performance.A comprehensive model of the interference fringe contrast based on the laser tracing system s measurement principle was established in this study.Simulation results based on ZEMAX verified the model.According to the simulation results,the placement angle of the analyzer had a direct influence on the interference fringe contrast.When the angle of the polarized light to the analyzer’s transmission axis increased from 65°to 85°,each contrast of the four-way interference fringes decreased from 0.9996 to 0.3528,the interference fringe contrast is decreased by 65%.Under the split ratio of beam splitters in the interference part(BS 1)of 5∶5,when the splitting ratio of BS 2 changed from 2∶8 to 8∶2,the fringe contrast of the interference signals received by the photodetectors increased,but the injection light intensity onto the PSD reflected by BS 2 decreased.The significant influence of the tracing performance was verified by the experiments.When splitting ratio of BS 2 increased,the contrast of the interference fringes increased.Due to the weakening of the incident light intensity of the PSD caused by the change of BS 2 splitting ratio,the response time of the tracing system is increased by 23.7 ms.As a result,the tracing performance of the laser tracing measurement optical system was degraded.An important theoretical basis was provided to evaluate and improve the accuracy and reliability of laser tracing measurement systems. 展开更多
关键词 interference fringe contrast laser tracing measurement high precision measurement ZEMAX.
下载PDF
A Novel Contour Tracing Algorithm for Object Shape Reconstruction Using Parametric Curves
13
作者 Nihat Arslan Kali Gurkahraman 《Computers, Materials & Continua》 SCIE EI 2023年第4期331-350,共20页
Parametric curves such as Bézier and B-splines, originally developedfor the design of automobile bodies, are now also used in image processing andcomputer vision. For example, reconstructing an object shape in an... Parametric curves such as Bézier and B-splines, originally developedfor the design of automobile bodies, are now also used in image processing andcomputer vision. For example, reconstructing an object shape in an image,including different translations, scales, and orientations, can be performedusing these parametric curves. For this, Bézier and B-spline curves can be generatedusing a point set that belongs to the outer boundary of the object. Theresulting object shape can be used in computer vision fields, such as searchingand segmentation methods and training machine learning algorithms. Theprerequisite for reconstructing the shape with parametric curves is to obtainsequentially the points in the point set. In this study, a novel algorithm hasbeen developed that sequentially obtains the pixel locations constituting theouter boundary of the object. The proposed algorithm, unlike the methods inthe literature, is implemented using a filter containing weights and an outercircle surrounding the object. In a binary format image, the starting point ofthe tracing is determined using the outer circle, and the next tracing movementand the pixel to be labeled as the boundary point is found by the filter weights.Then, control points that define the curve shape are selected by reducing thenumber of sequential points. Thus, the Bézier and B-spline curve equationsdescribing the shape are obtained using these points. In addition, differenttranslations, scales, and rotations of the object shape are easily provided bychanging the positions of the control points. It has also been shown that themissing part of the object can be completed thanks to the parametric curves. 展开更多
关键词 Contour tracing algorithm bézier curve B-spline curve object shape reconstruction
下载PDF
Practice and Exploration of Experiential Theme Landscape Design in Urban Historic Blocks: A Case Study of Shengjin Tower Folk Custom Historical Block in Nanchang
14
作者 FANG Qianghua FANG Huan XI Xingzhou 《Journal of Landscape Research》 2023年第6期35-42,46,共9页
Urban historic blocks are an important part of urban public space,but urban public space pays far less attention to users’experience,and there is a lack of design problem of experiential theme landscape.The landscape... Urban historic blocks are an important part of urban public space,but urban public space pays far less attention to users’experience,and there is a lack of design problem of experiential theme landscape.The landscape design practice of Shengjin Tower Folk Custom Historical Block in Nanchang provides an attempt to explore the design problem of experiential theme landscape.In this paper,the results of the design practice were sorted out and summarized,and the specific conception of the experiential design of urban public space was discussed from three aspects of the experiential control design,spatial experience design and serial experience design of the historic block on the basis of elaborating the design concept,so as to provide inspiration and reference for similar urban historic block projects. 展开更多
关键词 Experiential design Historic block LANDSCAPE Design practice
下载PDF
Pedestrian street and its effect on economic sustainability of a historical Middle Eastern city:The case of Chaharbagh Abbasi in Isfahan,Iran
15
作者 Soudabeh Shahmoradi Sayyed Mahdi Abtahi Pedro Guimaraes 《Geography and Sustainability》 CSCD 2023年第3期188-199,共12页
Pedestrianization is an urban revitalization strategy to enhance sustainability and livability in car-oriented cities.Despite many studies in this research field,the effects of pedestrianization on the economy of citi... Pedestrianization is an urban revitalization strategy to enhance sustainability and livability in car-oriented cities.Despite many studies in this research field,the effects of pedestrianization on the economy of cities in developing countries still need further investigation.Additionally,the impact of this strategy on the tenant mix of com-mercial and historical areas in Middle East countries is nebulous.To address these inadequacies,we considered Chaharbagh Abbasi street,located in the heart of Isfahan,Iran,and investigated the impact of a pedestrianization project with particular emphasis on how it affects the economic sustainability of existent commercial fabric.Pre-and post-project data along with field observations and quantifications used to assess structural replacements in trade,were analyzed with SPSS and ArcGIS software.The results revealed unexpected outcomes,such as the closure of some traditional businesses(27.5%),a stagnation in sales(69%)and a decrease in job offers(84%)leading the local economy to a fragile situation.Conversely,it was found that the footfall volume increased by 64% and 73% from the retailers’and pedestrians’viewpoints.This evolution along with a wide opening of food and beverage stores(approximately 60%)makes the post-pedestrianization results more promising than earlier predictions.In conclusion,these findings reinforce the importance of pedestrian streets in revitalizing economic activities in historical and commercial areas from the perspective of economic sustainability.Due to the lack of similar investigations in Middle East countries,these findings can support decision-makers and urban planners to take preventive measures in preserving the diversity of individual small shops for upcoming urban rehabilitation projects in terms of pedestrianization. 展开更多
关键词 Urban planning Pedestrianization Chaharbagh abbasi Sustainable Development Goals(SDGs) Economic sustainability Historic city centers
下载PDF
Point cloud-based environment reconstruction and ray tracing simulations for railway tunnel channels
16
作者 Ziyi Qi Ruisi He +6 位作者 Mi Yang Xuejian Zhang Bo Ai Weiming Li Shaopeng Wang Wenpu Sun Lizhe Li 《High-Speed Railway》 2023年第4期241-247,共7页
Radio propagation environment plays a critical role in the performance of wireless communication systems,and understanding channel characteristics is vital for ensuring reliable communication links and optimizing syst... Radio propagation environment plays a critical role in the performance of wireless communication systems,and understanding channel characteristics is vital for ensuring reliable communication links and optimizing system performance.Ray tracing is an effective method to investigate propagation characteristics in a complex environment,and how to quickly and accurately obtain environmental information needs to be solved.This paper presents dynamic environment reconstruction and ray tracing simulation in railway tunnel environment based on Simultaneous Localization and Mapping(SLAM)algorithm and Poisson reconstruction algorithm.Accurate channel parameters are obtained and analyzed based on ray tracing simulation.Both straight and curved tunnels are considered and investigated,and the results show the channel characteristics in complex railway tunnel environments. 展开更多
关键词 Railway communication TUNNELS Ray tracing Environment reconstruction Wireless channel
下载PDF
Functions of Karez to Xinjiang Agriculture in the Qing Dynasty from the Perspective of Historical Documents
17
作者 Danyang GONG 《Asian Agricultural Research》 2023年第3期70-71,共2页
Desertification is increasingly serious in Xinjiang,and the construction of water conservancy is a precondition for the development of agriculture.The main project for the development of agriculture and water conserva... Desertification is increasingly serious in Xinjiang,and the construction of water conservancy is a precondition for the development of agriculture.The main project for the development of agriculture and water conservancy in Xinjiang is to build Karez,which played a vital role in the development of Xinjiang agriculture in the Qing Dynasty.It has been recorded many times in historical documents of the Qing Dynasty,such as Lin Zexu s Diary,Tao Baolian s Diary,Xinjiang Atlas and Zuo Zongtang s Memorial to the Emperor,etc.,which recorded the situation and historical origin of Karez.Karez made a significant contribution to the development of agriculture in the Qing Dynasty.It increased the cultivated land in Xinjiang at that time,and increased the types and yields of crops.It is conducive to the stability and development of Xinjiang s economy.Until today,Karez is still an important water source for agricultural irrigation in Xinjiang. 展开更多
关键词 KAREZ historical documents in the Qing Dynasty Xinjiang agriculture
下载PDF
Tourism Development Mode of Historical and Cultural Blocks from the Perspective of Urban Renewal Based on Online Review Data:A Case Study of Nanluoguxiang in Beijing
18
作者 CHEN Liudan 《Journal of Landscape Research》 2023年第3期42-46,50,共6页
Under the background of urban renewal, this paper re-explores the tourism development modeof Nanluoguxiang historical and cultural block based on online review data, and puts forward correspondingdevelopment strategie... Under the background of urban renewal, this paper re-explores the tourism development modeof Nanluoguxiang historical and cultural block based on online review data, and puts forward correspondingdevelopment strategies. As a cultural label of a city, historical and cultural blocks should be updated first inorder to achieve sustainable development. By using multi-source big data review and qualitative researchmethods, the perception evaluation of tourists in Nanluoguxiang is obtained, and the shortcomings ofcurrent tourism development mode are analyzed. Furthermore, corresponding improvement strategies andsuggestions are put forward, in order to provide some effective ideas for the sustainable development ofhistorical and cultural blocks in the future. 展开更多
关键词 Online review data Tourism development mode historical and cultural block Nanluoguxiang
下载PDF
Use of a tissue clearing technique combined with retrograde trans-synaptic viral tracing to evaluate changes in mouse retinorecipient brain regions following optic nerve crush
19
作者 Zong-Yi Zhan Yi-Ru Huang +9 位作者 Lu-Wei Zhao Ya-Dan Quan Zi-Jing Li Di-Fang Sun Ya-Li Wu Hao-Yuan Wu Zi-Tian Liu Kai-Li Wu Yu-Qing Lan Min-Bin Yu 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第4期913-921,共9页
Successful establishment of reconnection between retinal ganglion cells and retinorecipient regions in the brain is critical to optic nerve regeneration.However,morphological assessments of retinorecipient regions are... Successful establishment of reconnection between retinal ganglion cells and retinorecipient regions in the brain is critical to optic nerve regeneration.However,morphological assessments of retinorecipient regions are limited by the opacity of brain tissue.In this study,we used an innovative tissue cleaning technique combined with retrograde trans-synaptic viral tracing to observe changes in retinorecipient regions connected to retinal ganglion cells in mice after optic nerve injury.Specifically,we performed light-sheet imaging of whole brain tissue after a clearing process.We found that pseudorabies virus 724(PRV724)mostly infected retinal ganglion cells,and that we could use it to retrogradely trace the retinorecipient regions in whole tissue-cleared brains.Unexpectedly,PRV724-traced neurons were more widely distributed compared with data from previous studies.We found that optic nerve injury could selectively modify projections from retinal ganglion cells in the hypothalamic paraventricular nucleus,intergeniculate leaflet,ventral lateral geniculate nucleus,central amygdala,basolateral amygdala,Edinger-Westphal nucleus,and oculomotor nucleus,but not the superior vestibular nucleus,red nucleus,locus coeruleus,gigantocellular reticular nucleus,or facial nerve nucleus.Our findings demonstrate that the tissue clearing technique,combined with retrograde trans-synaptic viral tracing,can be used to objectively and comprehensively evaluate changes in mouse retinorecipient regions that receive projections from retinal ganglion cells after optic nerve injury.Thus,our approach may be useful for future estimations of optic nerve injury and regeneration. 展开更多
关键词 histology image analysis light-sheet imaging optic nerve crush pseudorabies virus retinal ganglion cells three-dimensional imaging tissue clearing viral tracing whole brain study
下载PDF
Research on the Public Perception of Yangzhou Historical and Cultural Districts Based on Network Review Text Analysis
20
作者 WU Tao SHAO Yuanhua 《Journal of Landscape Research》 2023年第3期36-41,共6页
The historical and cultural districts of a city serve as important cultural heritage and tourism resources.This paper focused on four such districts in Yangzhou and performed semantic analysis on online public comment... The historical and cultural districts of a city serve as important cultural heritage and tourism resources.This paper focused on four such districts in Yangzhou and performed semantic analysis on online public comments using ROST CM6 software.According to the high frequency words,attention preference of district site elements,activities and feelings in Yangzhou historical and cultural districts were analyzed.Through the analysis of semantic network and public emotional tendency,the relationship between the protection and utilization of Yangzhou historical and cultural districts and the perception and demand of users were discussed,and some suggestions for the protection,utilization and renewal of historical and cultural districts were put forward. 展开更多
关键词 Yangzhou historical and cultural districts Text analysis Public perception Protection and renewal
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部