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Multi-source and multi-temporal remote sensing image classification for flood disaster monitoring
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作者 LI Zhu JIA Zhenyang +1 位作者 DONG Jing LIU Zhenghong 《Global Geology》 2025年第1期48-57,共10页
Flood disasters can have a serious impact on people's production and lives, and can cause hugelosses in lives and property security. Based on multi-source remote sensing data, this study establisheddecision tree c... Flood disasters can have a serious impact on people's production and lives, and can cause hugelosses in lives and property security. Based on multi-source remote sensing data, this study establisheddecision tree classification rules through multi-source and multi-temporal feature fusion, classified groundobjects before the disaster and extracted flood information in the disaster area based on optical imagesduring the disaster, so as to achieve rapid acquisition of the disaster situation of each disaster bearing object.In the case of Qianliang Lake, which suffered from flooding in 2020, the results show that decision treeclassification algorithms based on multi-temporal features can effectively integrate multi-temporal and multispectralinformation to overcome the shortcomings of single-temporal image classification and achieveground-truth object classification. 展开更多
关键词 multi-temporal decision tree classification flood disaster monitoring
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Multi-temporal InSAR-based landslide dynamic susceptibility mapping of Fengjie County,Three Gorges Reservoir Area,China
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作者 Feng Tian Wei Zhang +4 位作者 Hong-Hu Zhu Cui Wang Feng-Nian Chang Hou-Zhi Li Dao-Yuan Tan 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第12期7653-7664,共12页
Landslide susceptibility map(LSM)is a crucial tool for managing landslide hazards and identifying potential landslide areas.However,current LSMs rely primarily on static landslide-related factors with little variation... Landslide susceptibility map(LSM)is a crucial tool for managing landslide hazards and identifying potential landslide areas.However,current LSMs rely primarily on static landslide-related factors with little variation over several decades,thereby overlooking the movement of slopes and failing to capture landslide dynamics.The long-term ground deformation map(GDM)derived from multi-temporal interferometric synthetic aperture radar(MT-InSAR)can effectively address the shortcomings.Fengjie County is an important area for geohazard management in the Three Gorges Reservoir Area(TGRA),China.Landslides in this area,however,cause significant socio-economic loss due to geological,tectonic,climatic,and anthropological factors.This research aims to integrate random forest(RF)with MT-InSAR to generate a landslide dynamic susceptibility map(LDSM)for Fengjie County,enhancing the reliability of landslide risk management.First,the RF model was employed to generate a static LSM,whereas MT-InSAR was utilized to obtain the GDM of the study area from January 2020 to June 2023.The static LSM and the GDM were subsequently integrated using a dynamic weight matrix to derive the LDSM.Our analysis covered a temporal framework spanning three years,focusing on spatiotemporal changes in landslide susceptibility levels and the influence of climate factors.Compared with the static LSM,the LDSM can promptly identify moving landslide areas,reduce high landslide susceptibility areas,and achieve greater accuracy.Moreover,the spatiotemporal changes in landslide susceptibility are regulated by the total annual rainfall,with wet years being more conducive to landslides than dry years.The proposed LDSM offers useful insights for the dynamic prevention and refined management of landslide hazards in the TGRA,significantly enhancing the resilience in this region. 展开更多
关键词 Landslide susceptibility multi-temporal InSAR(MT-InSAR) Refined management of landslides Random forest
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Application of Assessment Scales in Palliative Care for Glioma:A Systematic Review
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作者 Zhi-Yuan Xiao Tian-Rui Yang +10 位作者 Ya-Ning Cao Wen-Lin Chen Jun-Lin Li Ting-Yu Liang Ya-Ning Wang Yue-Kun Wang Xiao-Peng Guo Yi Zhang Yu Wang Xiao-Hong Ning Wen-Bin Ma 《Chinese Medical Sciences Journal》 2025年第3期211-218,I0007,共9页
Background and Objective Patients with glioma experience a high symptom burden and have diverse palliative care needs.However,the assessment scales used in palliative care remain non-standardized and highly heterogene... Background and Objective Patients with glioma experience a high symptom burden and have diverse palliative care needs.However,the assessment scales used in palliative care remain non-standardized and highly heterogeneous.To evaluate the application patterns of the current scales used in palliative care for glioma,we aim to identify gaps and assess the need for disease-specific scales in glioma palliative care.Methods We conducted a systematic search of five databases including PubMed,Web of Science,Medline,EMBASE,and CINAHL for quantitative studies that reported scale-based assessments in glioma palliative care.We extracted data on scale characteristics,domains,frequency,and psychometric properties.Quality assessments were performed using the Cochrane ROB 2.0 and ROBINS-I tools.Results Of the 3,405 records initially identified,72 studies were included.These studies contained 75 distinct scales that were used 193 times.Mood(21.7%),quality of life(24.4%),and supportive care needs(5.2%)assessments were the most frequently assessed items,exceeding half of all scale applications.Among the various assessment dimensions,the Distress Thermometer(DT)was the most frequently used tool for assessing mood,while the Short Form-36 Health Survey Questionnaire(SF-36)was the most frequently used tool for assessing quality of life.The Mini Mental Status Examination(MMSE)was the most common tool for cognitive assessment.Performance status(5.2%)and social support(6.8%)were underrepresented.Only three brain tumor-specific scales were identified.Caregiver-focused scales were limited and predominantly burden-oriented.Conclusions There are significant heterogeneity,domain imbalances,and validation gaps in the current use of assessment scales for patients with glioma receiving palliative care.The scale selected for use should be comprehensive and user-friendly. 展开更多
关键词 GLIOMA palliative care assessment scales systematic review
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DDNet:A Novel Dynamic Lightweight Super-Resolution Algorithm for Arbitrary Scales
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作者 Yiqiao Gong Chunlai Wu +4 位作者 Wenfeng Zheng Siyu Lu Guangyu Xu Lijuan Zhang Lirong Yin 《Computer Modeling in Engineering & Sciences》 2025年第11期2223-2252,共30页
Recent Super-Resolution(SR)algorithms often suffer from excessive model complexity,high computational costs,and limited flexibility across varying image scales.To address these challenges,we propose DDNet,a dynamic an... Recent Super-Resolution(SR)algorithms often suffer from excessive model complexity,high computational costs,and limited flexibility across varying image scales.To address these challenges,we propose DDNet,a dynamic and lightweight SR framework designed for arbitrary scaling factors.DDNet integrates a residual learning structure with an Adaptively fusion Feature Block(AFB)and a scale-aware upsampling module,effectively reducing parameter overhead while preserving reconstruction quality.Additionally,we introduce DDNetGAN,an enhanced variant that leverages a relativistic Generative Adversarial Network(GAN)to further improve texture realism.To validate the proposed models,we conduct extensive training using the DIV2K and Flickr2K datasets and evaluate performance across standard benchmarks including Set5,Set14,Urban100,Manga109,and BSD100.Our experiments cover both symmetric and asymmetric upscaling factors and incorporate ablation studies to assess key components.Results show that DDNet and DDNetGAN achieve competitive performance compared with mainstream SR algorithms,demonstrating a strong balance between accuracy,efficiency,and flexibility.These findings highlight the potential of our approach for practical real-world super-resolution applications. 展开更多
关键词 DDNet DDNetGAN fully dynamic LIGHTWEIGHT arbitrary scale super-resolution algorithm
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Ignoring atypical symptoms of depression in common scales
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作者 Evgeny D Kasyanov Yana V Yakovleva +1 位作者 Egor S Shchepkin Galina E Mazo 《World Journal of Psychiatry》 2025年第11期367-375,共9页
BACKGROUND Atypical depression is an important indicator of a high risk of bipolar disorder and a genetic predisposition to immunometabolic traits.AIM To analyze common depression assessment scales for their inclusion... BACKGROUND Atypical depression is an important indicator of a high risk of bipolar disorder and a genetic predisposition to immunometabolic traits.AIM To analyze common depression assessment scales for their inclusion of items related to atypical symptoms such as mood reactivity,hypersomnia,increased appetite(or weight gain),leaden paralysis,and interpersonal sensitivity.METHODS A search for English-language articles was conducted without time restrictions in the MEDLINE and Russian Science Citation Index databases using the following keywords:“depression”OR“bipolar depression”AND“scales”OR“questionnaires”.The analytical method used in this review involved a descriptive analysis of the included studies.RESULTS After reviewing studies on the validation of depression assessment scales,we found that only a small number include items addressing both increases and decreases in appetite or weight,as well as variations in sleep duration.Moreover,only a few studies have evaluated mood reactivity,leaden paralysis,and interpersonal sensitivity.The most well-developed scale that considers all aspects of atypical and non-atypical depressions is the Inventory of Depressive Symptomatology.CONCLUSION Ignoring atypical symptoms in common scales can lead to underestimation of depression severity and inaccuracies in evaluating therapy effectiveness in clinical trials, as well as hinder fundamental research aimed at finding biomarkers. 展开更多
关键词 Atypical depression Bipolar disorder Mood reactivity Depression assessment scales Inventory of Depressive Symptomatology
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Tracking spatial heterogeneity of local degree of saturation in unsaturated soils at different scales via X-ray computed tomography
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作者 Zhenliang Jiang Jianbin Liu Anthony Kwan Leung 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第6期3807-3818,共12页
Correctly tracking the evolution of spatial heterogeneity of local degree of saturation(Sr)in unsaturated soils is essential to explain the seepage phenomenon,which is crucial to assessing slope stability.Several meth... Correctly tracking the evolution of spatial heterogeneity of local degree of saturation(Sr)in unsaturated soils is essential to explain the seepage phenomenon,which is crucial to assessing slope stability.Several methods exist for quantifying the heterogeneity of local S_(r).However,a comprehensive comparison of these methods in terms of accuracy,relative advantages,and disadvantages is currently lacking.This paper presents a comparative analysis of local Sr obtained at multiple scales,ranging from the element scale to the slice,representative element volume(REV),pore,and voxel scales.The spatial heterogeneity of Sr in an unsaturated glass beads specimen at different matric suctions was visualised and quantified by multiscale X-ray micro-focus computed tomography image-based analysis methods.Local Sr obtained at different scales displayed a comparable trend along the sample depth,yet the REV-scale method showed a much scattered and discontinuous distribution.In contrast,the pore-scale method detected a distinct two-clustered,bimodal distribution of S_(r).The pore-scale method has the highest integrated resolution,as it has the highest spatial resolution(i.e.number of data points)and provides more information(i.e.number of extractable physical parameters).This method thus provides a more effective approach for tracking the spatial heterogeneity of S_(r).Based on this method,pore-scale water retention curves were determined,offering new quantitative means to characterise pore water heterogeneity and explainwater drainage processes such as hysteresis at the pore scale. 展开更多
关键词 Unsaturated soils Degree of saturation Computed tomography(CT)image-based analysis Multiscale Pore scale
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Why knowledge graphs are essential for harmonizing heterogeneous geologic time scales
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作者 Hongwei Wang Chao Ma +2 位作者 Xiaogang Ma James G.Ogg Chengshan Wang 《Episodes》 2025年第4期565-577,共13页
Geologic time is an essential dimension in geological research,acting as a pivotal attribute that integrates data across various subdisciplines.The Geologic Time Scale(GTS)provides a formal framework for interpreting ... Geologic time is an essential dimension in geological research,acting as a pivotal attribute that integrates data across various subdisciplines.The Geologic Time Scale(GTS)provides a formal framework for interpreting and communicating geologic time within the field of geological studies,such as macro-geological evolution and regional geologic surveys. 展开更多
关键词 interpreting communicating geologic time geological studiessuch geologic time scales integrates data across various subdisciplinesthe HARMONIZATION knowledge graphs geological researchacting regional geologic surveys
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Scales,methods and technical analysis of China's residential environment evaluation 被引量:2
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作者 李绥 石铁矛 周乐 《Journal of Southeast University(English Edition)》 EI CAS 2009年第2期274-277,共4页
To improve China's residential environment evaluation system and enhance its guiding role, current research results are analyzed and summarized from three aspects including research scales, evaluation methods and app... To improve China's residential environment evaluation system and enhance its guiding role, current research results are analyzed and summarized from three aspects including research scales, evaluation methods and applied technology by means of comparison, induction and empirical application. The guiding role of the current macro-scale evaluation system of urban planning and construction is generally not obvious, whereas the guiding role of medium and micro-scale systems to the improvement of residential environments is improving. There are diversified methods for determining the threshold values and the weights of indices in China's evaluation system. For instance, the analytic hierarchy process(AHP) method is adopted to determine the weights of indices. The advantages and disadvantages of the method are analyzed on the basis of empirical calculation. In the course of comprehensive analyses, a nonlinear model can reflect interactions among indices more than a linear model; the evaluation model under the ARCGIS platform prevails since it combines space and attribute, and it has intuitive results. So far, the methodological system of China's residential environment evaluation has not been established; its subject coverage and research category should be expanded, and its guiding role should be enhanced. 展开更多
关键词 residential environment evaluation system scale threshold value WEIGHT evaluation model geographic information system (GIS)
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Study on the scales of heterogeneous geologic bodies in random media 被引量:2
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作者 李灿苹 刘学伟 《Applied Geophysics》 SCIE CSCD 2011年第4期363-369,373,共8页
In order to study the scale characteristics of heterogeneities in complex media, a random medium is constructed using a statistical method and by changing model parameters (autocorrelation lengths a and b), the scal... In order to study the scale characteristics of heterogeneities in complex media, a random medium is constructed using a statistical method and by changing model parameters (autocorrelation lengths a and b), the scales of heterogeneous geologic bodies in the horizontal and the vertical Cartesian directions may be varied in the medium. The autocorrelation lengths a and b represent the mean scale of heterogeneous geologic bodies in the horizontal and vertical Cartesian directions in the randQm medium, respectively. Based on this model, the relationship between model autocorrelation lengths and heterogeneous geologic body scales is studied by horizontal velocity variation and standard deviation. The horizontal velocity variation research shows that velocities are in random perturbation. The heterogeneous geologic body scale increases with increasing autocorrelation length. The recursion equation for the relationship between autocorrelation lengths and heterogeneous geologic body scales is determined from the velocity standard deviation research and the actual heterogeneous geologic body scale magnitude can be estimated by the equation. 展开更多
关键词 random medium autocorrelation length velocity standard deviation heterogeneous geologic body scale
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Effect of Phytohormones on Adventitious Bud Differentiation from Bulb Scales of Oriental Lily Test-tube Plantlets
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作者 王菲彬 王斐 +1 位作者 管玲玲 胡凤荣 《Agricultural Science & Technology》 CAS 2013年第10期1365-1368,1382,共5页
[Objective] The purpose of this study is to investigate the effects of differ- ent phytohormones on the adventitious bud differentiation of oriental lily. [Method] The bulb scales of the test-tube plantlets of Tiber, ... [Objective] The purpose of this study is to investigate the effects of differ- ent phytohormones on the adventitious bud differentiation of oriental lily. [Method] The bulb scales of the test-tube plantlets of Tiber, Rodina and Constanta were cul- tured in media supplemented with different cytokinin and auxin at different concen- tration, and then the adventitious buds in each treatment were calculated. [Result] Cytokinins had different influence on the adventitious bud differentiation of the three oriental lily cultivars. Among them, 6-BA had the best effect to induce the adventi- tious bud differentiation from bulb scales of Tiber and Rodina, but there was some difference in the optimal concentration. KT had the best effect to induce the adven- titious bud differentiation of Constanta. The auxins had little influence on the quality of the adventitious bud of the three oriental lily cultivars, but caused some difference in differentiation coefficients. [Conclusion] The most suitable media for the adventi- tious bud differentiation from bulb scales in vitro of Tiber, Rodina and Constanta were MS+0.2 mg/L 6-BA+0.2 mg/L 2,4-D, MS+I.0 mg/L 6-BA+0.2 mg/L IAA, MS+ 1.0 mg/L KT+0.5 mg/L 2,4-D, respectively. 展开更多
关键词 Oriental lily Bulb scales of test-tube plantlets PHYTOHORMONE Tissue culture
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多重障碍学生的学业评价——英国“P Scales”述评
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作者 盛永进 《现代特殊教育》 2019年第5期12-18,共7页
“P Scales”是英国教育部用于评价多重等严重障碍学生学业的评估工具,其把低于国家课程1级水平的学业表现分为八个等级,内容包含国家课程中的所有学科科目。“P Scales”的设计基于对学生早期交流、互动和认知发展水平的研究,采取学科... “P Scales”是英国教育部用于评价多重等严重障碍学生学业的评估工具,其把低于国家课程1级水平的学业表现分为八个等级,内容包含国家课程中的所有学科科目。“P Scales”的设计基于对学生早期交流、互动和认知发展水平的研究,采取学科导向的分层设计与表现性的内容描述,既概述了有学习困难的学生可能表现出来的一般情况,又将多重等严重障碍学生的学习纳入国家课程标准体系。 展开更多
关键词 多重障碍学生 学业评价 P scales
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Bowel preparation quality scales for colonoscopy 被引量:59
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作者 David Kastenberg Gerald Bertiger Stuart Brogadir 《World Journal of Gastroenterology》 SCIE CAS 2018年第26期2833-2843,共11页
Colorectal cancer(CRC) is the third most common cancer and second leading cause of cancer-related death in the United States. Colonoscopy is widely preferred for CRC screening and is the most commonly used method in t... Colorectal cancer(CRC) is the third most common cancer and second leading cause of cancer-related death in the United States. Colonoscopy is widely preferred for CRC screening and is the most commonly used method in the United States. Adequate bowel preparation is essential for successful colonoscopy CRC screening. However, up to one-quarter of colonoscopies are associated with inadequate bowel preparation, which may result in reduced polyp and adenoma detection rates, unsuccessful screens, and an increased likelihood of repeat procedure. In addition, standardized criteria and assessment scales for bowel preparation quality are lacking. While several bowel preparation quality scales are referred to in the literature, these differ greatly in grading methodology and categorization criteria. Published reliability and validity data are available for five bowel preparation quality assessment scales, which vary in several key attributes. However, clinicians and researchers continue to use a variety of bowel preparation quality measures, including nonvalidated scales, leading to potential confusion and difficulty when comparing quality results among clinicians and across clinical trials. Optimal clinical criteria for bowel preparation quality remain controversial. The use of validated bowel preparation quality scales with stringent but simple scoring criteria would help clarify clinical trial data as well as the performance of colonoscopy in clinical practice related to quality measurements. 展开更多
关键词 COLONOSCOPY BOWEL PREPARATION Aronchick scale Ottawa BOWEL PREPARATION scale BOSTON BOWEL PREPARATION scale
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Trends and Scales of Observed Soil Moisture Variations in China 被引量:11
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作者 聂肃平 罗勇 朱江 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2008年第1期43-58,共16页
A new soil moisture dataset from direct gravimetric measurements within the top 50-cm soil layers at 178 soil moisture stations in China covering the period 1981 1998 are used to study the long-term and seasonal trend... A new soil moisture dataset from direct gravimetric measurements within the top 50-cm soil layers at 178 soil moisture stations in China covering the period 1981 1998 are used to study the long-term and seasonal trends of soil moisture variations, as well as estimate the temporal and spatial scales of soil moisture for different soil layers. Additional datasets of precipitation and temperature difference between land surface and air (TDSA) are analyzed to gain further insight into the changes of soil moisture. There are increasing trends for the top 10 cm, but decreasing trends for the top 50 cm of soil layers in most regions. Trends in precipitation appear to dominantly influence trends in soil moisture in both cases. Seasonal variation of soil moisture is mainly controlled by precipitation and evaporation, and in some regions can be affected by snow cover in winter. Timescales of soil moisture variation are roughly 1-3 months and increase with soil depth. Further influences of TDSA and precipitation on soil moisture in surface layers, rather than in deeper layers, cause this phenomenon. Seasonal variations of temporal scales for soil moisture are region-dependent and consistent in both layer depths. Spatial scales of soil moisture range from 200-600 km, with topography also having an affect on these. Spatial scales of soil moisture in plains are larger than in mountainous areas. In the former, the spatial scale of soil moisture follows the spatial patterns of precipitation and evaporation, whereas in the latter, the spatial scale is controlled by topography. 展开更多
关键词 soil moisture TREND temporal scale spatial scale
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The Microstructures of Butterfly Wing Scales in Northeast of China 被引量:9
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作者 Li-yan Wu Zhi-wu Han Zhao-mei Qiu Hui-ying Guan Lu-quan Ren 《Journal of Bionic Engineering》 SCIE EI CSCD 2007年第1期47-52,共6页
There are billions of tiny scales on the butterfly wings, which array regularly as the tiles on the roof. Such tilts can form various colors of the wing and afford the species many abilities to survive and propagate. ... There are billions of tiny scales on the butterfly wings, which array regularly as the tiles on the roof. Such tilts can form various colors of the wing and afford the species many abilities to survive and propagate. Morphological experiments on the wing scales of six butterfly species living in northeast of China were conducted. By the optics microscope; the form, geometry dimension and array of the scales were observed generally. By using scanning electron microscope (SEM), the 2D scanning and measurement were carried out and the surface micro configurations of scales were observed. The dimension and microstructure characteristics of the cross section of single scale were achieved through transmission electron microscope (TEM). Finally, by using 3D software, three 3D models were described and the 3D visual effect was achieved. This work can put forward a basic method for the future study on the morphology of biological microstructure. 展开更多
关键词 BUTTERFLY WING scale microstructure MICROSCOPE
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Reconstruction of different scales of pore-fractures network of coal reservoir and its permeability prediction with Monte Carlo method 被引量:10
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作者 Ni Xiaoming Chen Wenxue +1 位作者 Li Zheyuan Gao Xiang 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2017年第4期693-699,共7页
There are millimeter, micron and nanometer scales of pores and fractures in coal to describe different scales of coal pores and fissures communicating path and to quantitatively characterize their permeability. Such i... There are millimeter, micron and nanometer scales of pores and fractures in coal to describe different scales of coal pores and fissures communicating path and to quantitatively characterize their permeability. Such information provides an important basis for studying coalbed methane output mechanism. The pores and fissures in a large number of coal samples were observed and counted by scanning electron microscopy and optical microscopy. The probability distribution models of pore-fissure network were then established. Different scales of pore-fissures 2D network models were reconstructed by Monte Carlo method. The 2D seepage models were obtained through assignment zero method and using Matlab software. The effect of permeability on different scale pore-fractures network was obtained by two-dimensional seepage equation. Predicted permeability is compared with the measured ones. The results showed that the dominant order of different scale pore-fractures connected path from high to low is millimeter-sized fractures, seepage pores and micron-size fractures. The contribution of coal reservoir permeability from large to small is millimeter-size fractures, micron-size fractures and seepage pores. Different parameters in different scale pore-fractures are of different influence permeability.Reconstruction of different scale pore-fractures network can clearly display the connectivity of porefractures, which can provide a basis for selecting migration path and studying gas flow pattern. 展开更多
关键词 Fractures network Different scales RECONSTRUCTION PERMEABILITY
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Two-Body Abrasive Wear of the Surfaces of Pangolin Scales 被引量:14
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作者 Jin Tong Tie-biao Lu +3 位作者 Yun-hai Ma Heng-kun Wang Lu-quan Ren R. D. Arnell 《Journal of Bionic Engineering》 SCIE EI CSCD 2007年第2期77-84,共8页
The Pangolin, a soil-burrowing animal, is covered with scales. These scales are often abraded by soil and rock and their surface is corrugated. The abrasive wear of the surface of the scales was examined. The scales w... The Pangolin, a soil-burrowing animal, is covered with scales. These scales are often abraded by soil and rock and their surface is corrugated. The abrasive wear of the surface of the scales was examined. The scales were taken from a pangolin that had died of natural causes. The tests were run on a rotary disc abrasive wear tester. The abrasive material was quartz sand (96.5 wt.%) and bentonite (3.5 wt.%). The morphology of the abraded surfaces and the abrasion were examined by stereoscopic microscopy and scanning electron microscopy. The concepts are proposed of "Guiding-Effect" and "Rolling-Effect" on the textured surfaces under free abrasive wear conditions and the critical dimensions of the "Rolling-Effect" are discussed. 展开更多
关键词 pangolin scale surface morphology abrasive wear
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Noether symmetry and conserved quantity for dynamical system with non-standard Lagrangians on time scales 被引量:12
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作者 宋静 张毅 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第8期201-209,共9页
This paper focuses on studying the Noether symmetry and the conserved quantity with non-standard Lagrangians, namely exponential Lagrangians and power-law Lagrangians on time scales. Firstly, for each case, the Hamilt... This paper focuses on studying the Noether symmetry and the conserved quantity with non-standard Lagrangians, namely exponential Lagrangians and power-law Lagrangians on time scales. Firstly, for each case, the Hamilton prin- ciple based on the action with non-standard Lagrangians on time scales is established, with which the corresponding Euler-Lagrange equation is given. Secondly, according to the invariance of the Hamilton action under the infinitesimal transformation, the Noether theorem for the dynamical system with non-standard Lagrangians on time scales is established. The proof of the theorem consists of two steps. First, it is proved under the infinitesimal transformations of a special one-parameter group without transforming time. Second, utilizing the technique of time-re-parameterization, the Noether theorem in a general form is obtained. The Noether-type conserved quantities with non-standard Lagrangians in both clas- sical and discrete cases are given. Finally, an example in Friedmann-Robertson-Walker spacetime and an example about second order Duffing equation are given to illustrate the application of the results. 展开更多
关键词 time scale non-standard Lagrangian Noether symmetry conserved quantity
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Generalized Chaplygin equations for nonholonomic systems on time scales 被引量:7
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作者 金世欣 张毅 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第2期267-272,共6页
The generalized Chaplygin equations for nonholonomic systems on time scales are proposed and studied. The Hamil- ton principle for nonholonomic systems on time scales is established, and the corresponding generalized ... The generalized Chaplygin equations for nonholonomic systems on time scales are proposed and studied. The Hamil- ton principle for nonholonomic systems on time scales is established, and the corresponding generalized Chaplygin equa- tions are deduced. The reduced Chaplygin equations are also presented. Two special cases of the generalized Chaplygin equations on time scales, where the time scales are equal to the set of real numbers and the integer set, are discussed. Finally, several examples are given to illustrate the application of the results. 展开更多
关键词 nonholonomic system generalized Chaplygin equations time scales
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OSCILLATION FOR NONAUTONOMOUS NEUTRAL DYNAMIC DELAY EQUATIONS ON TIME SCALES 被引量:6
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作者 刘爱莲 吴洪武 +1 位作者 朱思铭 Ronald M.Mathsen 《Acta Mathematica Scientia》 SCIE CSCD 2006年第1期99-106,共8页
The article is concerned with oscillation of nonautonomous neutral dynamic delay equations on time scales. Sufficient conditions are established for the existence of bounded positive solutions and for oscillation of a... The article is concerned with oscillation of nonautonomous neutral dynamic delay equations on time scales. Sufficient conditions are established for the existence of bounded positive solutions and for oscillation of all solutions of this equation. Some results extend known results for difference equations when the time scale is the set Z^+ of positive integers and for differential equations when the time scale is the set IR of real numbers. 展开更多
关键词 Time scale Δ-derivative neutral delay equation OSCILLATION
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