期刊文献+
共找到117,602篇文章
< 1 2 250 >
每页显示 20 50 100
Multi-source and multi-temporal remote sensing image classification for flood disaster monitoring
1
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
在线阅读 下载PDF
Multi-temporal InSAR-based landslide dynamic susceptibility mapping of Fengjie County,Three Gorges Reservoir Area,China
2
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
在线阅读 下载PDF
Application of Assessment Scales in Palliative Care for Glioma:A Systematic Review
3
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
暂未订购
DDNet:A Novel Dynamic Lightweight Super-Resolution Algorithm for Arbitrary Scales
4
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
在线阅读 下载PDF
Ignoring atypical symptoms of depression in common scales
5
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
暂未订购
Tracking spatial heterogeneity of local degree of saturation in unsaturated soils at different scales via X-ray computed tomography
6
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
在线阅读 下载PDF
Developing and Assessing the Reliability–Validity of the Chinese Arbitrator Competency Scale
7
作者 Jiang Jindong Wei Ping 《Contemporary Social Sciences》 2026年第1期123-139,共17页
Arbitration is a key non-litigation commercial mechanism for the resolution of disputes, and the quality and credibility of its awards depend largely on the competency of the arbitrators. However, the selection and ev... Arbitration is a key non-litigation commercial mechanism for the resolution of disputes, and the quality and credibility of its awards depend largely on the competency of the arbitrators. However, the selection and evaluation systems for arbitrators in China have long faced challenges such as the vague criteria for competency and an unclear professionalization path for arbitrators. To address these issues, this study is grounded in the context of actual Chinese arbitration practice and based on the competency iceberg model. Through a methodological approach encompassing literature reviews, behavioral event interviews, expert revisions, and questionnaire surveys, a Chinese Arbitrator Competency Scale was developed and validated in this study. Examination of the findings indicated that the scale needed to consist of five dimensions—communication and coordination, cognitive skills, ethical conduct, work motivation, and personality traits—and possess a total of 28 specific indicators. Confirmatory analysis of the factors demonstrates a good fit for the five-dimensional model, with each of the dimensions exhibiting high reliability and validity. This scale is innovative in integrating the competency elements with Chinese characteristics, such as commercial acumen, crosscultural mediation skills, and adaptability to the local rule of law. This research not only enriches the competency theory in regard to the field of human resource management but also provides a scientific framework of standards and measurement tools for the selection, training, and evaluation of arbitrators. It thus has significant practical value for enhancing the professionalism and international competitiveness of China's arbitration system. 展开更多
关键词 arbitrators competency scale scale development reliability-validity assessment
在线阅读 下载PDF
Multi-Time Scale Optimization Scheduling of Data Center Considering Workload Shift and Refrigeration Regulation
8
作者 Luyao Liu Xiao Liao +1 位作者 Yiqian Li Shaofeng Zhang 《Energy Engineering》 2026年第2期451-486,共36页
Data center industries have been facing huge energy challenges due to escalating power consumption and associated carbon emissions.In the context of carbon neutrality,the integration of data centers with renewable ene... Data center industries have been facing huge energy challenges due to escalating power consumption and associated carbon emissions.In the context of carbon neutrality,the integration of data centers with renewable energy has become a prevailing trend.To advance the renewable energy integration in data centers,it is imperative to thoroughly explore the data centers’operational flexibility.Computing workloads and refrigeration systems are recognized as two promising flexible resources for power regulationwithin data centermicro-grids.This paper identifies and categorizes delay-tolerant computing workloads into three types(long-running non-interruptible,long-running interruptible,and short-running)and develops mathematical time-shifting models for each.Additionally,this paper examines the thermal dynamics of the computer room and derives a time-varying temperature model coupled to refrigeration power.Building on these models,this paper proposes a two-stage,multi-time scale optimization scheduling framework that jointly coordinates computing workloads time-shift in day-ahead scheduling and refrigeration power control in intra-day dispatch to mitigate renewable variability.A case study demonstrates that the framework effectively enhances the renewable-energy utilization,improves the operational economy of the data center microgrid,and mitigates the impact of renewable power uncertainty.The results highlight the potential of coordinated computing workloads and thermal system flexibility to support greener,more cost-effective data center operation. 展开更多
关键词 Data center renewable energy load shift multi-time scale optimization
在线阅读 下载PDF
A Scale Separation Hybrid Predictive Model and Its Application to Predict Summer Monthly Precipitation in Northeast China
9
作者 Lei YU Aihui WANG Changzheng LIU 《Advances in Atmospheric Sciences》 2026年第3期504-528,共25页
Northeast China serves as an important crop production region.Accurately forecasting summer precipitation in Northeast China(NEC-PR)has been a challenge due to its wide range of time scales influenced by varying clima... Northeast China serves as an important crop production region.Accurately forecasting summer precipitation in Northeast China(NEC-PR)has been a challenge due to its wide range of time scales influenced by varying climatic conditions.This study presents a scale separation hybrid statistical model with recurrent neural network(SS-RNN)to predict the summer monthly NEC-PR.The SS-RNN model decomposes the multiple scales of the NEC-PR into several spatiotemporal intrinsic mode functions covering annual to decadal time scales.This strategy provides a way to derive appropriate predictors and establish predictive models for the primary spatial modes of the NEC-PR at various time scales.Our results demonstrate substantial improvements by the SS-RNN model in predicting the summer monthly NEC-PR as compared with dynamic models,particularly in predicting the spatial pattern of the NEC-PR.In this paper we take August,the month of the highest NEC-PR,to assess our model skill.Independent forecasts of the August NEC-PR over the period 2021–24 achieve significant spatial anomaly correlation coefficients,reaching a maximum value of 0.83.Additional verifications by station observations show that the model hits most station anomalies,achieving a mean predictive skill score of 90. 展开更多
关键词 Northeast China precipitation scale separation approach statistical predictive model recurrent neural network predictive model
在线阅读 下载PDF
Multi-Timescale Coordinated Optimal Dispatch of Active Distribution Networks Incorporating Thermal Storage Electric Heating Clusters
10
作者 Song Zhang Yang Yu +1 位作者 Shuguang Li Xue Li 《Energy Engineering》 2026年第3期459-480,共22页
Thermal storage electric heating(TSEH),as a prevalent variable load resource,offers significant potential for enhancing system flexibility when aggregated into a cluster.To address the uncertainties of renewable energ... Thermal storage electric heating(TSEH),as a prevalent variable load resource,offers significant potential for enhancing system flexibility when aggregated into a cluster.To address the uncertainties of renewable energy and load forecasting in active distribution networks(ADN),this paper proposes a multi-timescale coordinated optimal dispatch strategy that incorporates TSEH clusters.It utilizes the thermal storage characteristics and short-term regulation capabilities of TSEH,along with the rapid and gradual response characteristics of resources in active distribution grids,to develop a coordinated optimization dispatch mechanism for day-ahead,intraday,and real-time stages.It provides a coordinated optimized dispatch technique across several timescales for active distribution grids,taking into account the integration of TSEH clusters.The proposed method is validated on a modified IEEE 33-node system.Simulation results demonstrate that the participation of TSEH in collaborative optimization significantly reduces the total system operating cost by 8.71%compared to the scenario without TSEH.This cost reduction is attributed to a 10.84%decrease in interaction costs with the main grid and a 47.41%reduction in network loss costs,validating effective peak shaving and valley filling.The multi-timescale framework further enhances economic efficiency,with overall operating costs progressively decreasing by 3.91%(intraday)and 4.59%(real-time),and interaction costs further reduced by 5.34%and 9.25%,respectively.Moreover,the approach enhances system stability by effectively suppressing node voltage fluctuations and ensuring all voltages remain within safe operating limits during real-time operation.Therefore,the proposed approach achieves rational coordination of diverse resources,significantly improving the economic efficiency and stability of ADNs. 展开更多
关键词 Active distribution network thermal storage electric heating distributed energy resources rolling optimization multiple time scales
在线阅读 下载PDF
The Interaction Mechanism Between Urban Scale Hierarchy and Urban Networks in China:An Analysis Based on A Spatial Simultaneous Equation Model
11
作者 ZHOU Ying ZHENG Wensheng WANG Xiaofang 《Chinese Geographical Science》 2026年第1期19-33,共15页
Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefor... Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefore,this paper analyzes the spatial interaction between urban scale hierarchy and urban networks in China from 2019 to 2023,drawing on Baidu migration data and employing a spatial simultaneous equation model.The results reveal a significant positive spatial correlation between cities with higher hierarchy and those with greater network centrality.Within a static framework,we identify a positive interaction between urban scale hierarchy and urban network centrality,while their spatial cross-effects manifest as negative neighborhood interactions based on geographical distance and positive cross-scale interactions shaped by network connections.Within a dynamic framework,changes in urban scale hierarchy and urban networks are mutually reinforcing,thereby widening disparities within the urban hierarchy.Furthermore,an increase in a city’s network centrality had a dampening effect on the population growth of neighboring cities and network-connected cities.This study enhances understanding of the spatial organisation of urban systems and offers insights for coordinated regional development. 展开更多
关键词 urban scale hierarchy urban networks spatial interaction spatial spillover effect Baidu migration data spatial simultaneous equation model China
在线阅读 下载PDF
Uniform wafer-scale MOCVD homoepitaxy of β-Ga_(2)O_(3)on 2-inch(010)substrates
12
作者 Xuanze Zhou Haozhong Wu +7 位作者 Yuanjie Ding Ziyuan Wang Zhiyu Zhou Ning Xia Song Zhang Guangwei Xu Hui Zhang Shibing Long 《Chinese Physics B》 2026年第1期576-580,共5页
The(010)orientation ofβ-Ga_(2)O_(3)is a highly promising platform for next-generation lateral power electronics due to its superior theoretical transport properties.However,progress has been impeded by the unavailabi... The(010)orientation ofβ-Ga_(2)O_(3)is a highly promising platform for next-generation lateral power electronics due to its superior theoretical transport properties.However,progress has been impeded by the unavailability of large-area substrates,limiting studies to small-scale samples.Leveraging the recent emergence of 2-inch wafers,we report the first demonstration of homoepitaxial growth on a 2-inch,Fe-doped semi-insulating(010)β-Ga_(2)O_(3)substrate by metal-organic chemical vapor deposition(MOCVD).A systematic,wafer-scale characterization reveals the successful growth of a highquality epitaxial film.High-resolution x-ray diffraction shows an excellent crystalline structure,with a rocking curve full-width ranging from 21.0 arcsec to 103.0 arcsec.Atomic force microscopy confirms an atomically smooth surface with a root-mean-square roughness below 1.53 nm,displaying a distinct step-flow growth mode across the wafer.Furthermore,mercury-probe capacitance-voltage mapping indicates a well-controlled carrier concentration of~2×10~(18)cm~(-3)with a RSD of 5.12%.This work provides the first comprehensive assessment of 2-inch(010)Ga_(2)O_(3)epitaxial wafers,validating a critical material platform for the development and future manufacturing of high-performance power devices. 展开更多
关键词 β-Ga_(2)O_(3) metal-organic chemical vapor deposition(MOCVD) wafer scale UNIFORMITY
原文传递
ScaleMamba-YOLO:基于MambaYOLO的多尺度医学目标检测模型
13
作者 覃晓 钱泉梅 《南宁师范大学学报(自然科学版)》 2026年第2期63-75,共13页
针对MambaYOLO在医学影像分析中存在的多尺度适应性不足(病灶尺寸差异大导致固定感受野效果受限)和背景干扰敏感(正常组织噪声影响检测)2个关键问题,本研究提出了一种基于MambaYOLO的多尺度医学目标检测模型ScaleMamba-YOLO。首先,针对... 针对MambaYOLO在医学影像分析中存在的多尺度适应性不足(病灶尺寸差异大导致固定感受野效果受限)和背景干扰敏感(正常组织噪声影响检测)2个关键问题,本研究提出了一种基于MambaYOLO的多尺度医学目标检测模型ScaleMamba-YOLO。首先,针对尺度特征捕捉不足的问题,设计了医学多尺度局部特征增强模块(Medical Multi-scale Local Feature Enhancement Block),通过异构卷积核并行架构实现病理特征的全尺度覆盖,实现了对微小病灶和弥散性大病灶的协同检测。其次,为了减少背景噪声放大,提出特征聚合提取模块(Partial-enhanced C2F),采用部分卷积技术选择性保留关键特征通道,有效抑制了医学影像中正常组织区域的背景干扰。最后,为了验证模型的有效性,在Br35H(脑部MRI肿瘤)和PLoPy(结肠镜息肉)两个典型的公开医学数据集上进行了测试。实验结果表明,ScaleMamba-YOLO模型的平均精度均值(AP)分别达到72.7%和85.7%,相较于基线MambaYOLO模型,AP分别提升了2.2个百分点和1.7个百分点。这表明ScaleMamba-YOLO模型能有效克服多尺度适应性不足和背景干扰问题,可以显著提升模型对不同尺寸医学病灶的检测精度。 展开更多
关键词 Mamba MambaYOLO 多尺度特征融合 局部特征增强 医学影像分析
在线阅读 下载PDF
Scales,methods and technical analysis of China's residential environment evaluation 被引量:2
14
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)
在线阅读 下载PDF
Study on the scales of heterogeneous geologic bodies in random media 被引量:2
15
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
在线阅读 下载PDF
Effect of Phytohormones on Adventitious Bud Differentiation from Bulb Scales of Oriental Lily Test-tube Plantlets
16
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
在线阅读 下载PDF
多重障碍学生的学业评价——英国“P Scales”述评
17
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
在线阅读 下载PDF
Bowel preparation quality scales for colonoscopy 被引量:61
18
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
暂未订购
Trends and Scales of Observed Soil Moisture Variations in China 被引量:11
19
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
在线阅读 下载PDF
The Microstructures of Butterfly Wing Scales in Northeast of China 被引量:9
20
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
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部