期刊文献+
共找到219,005篇文章
< 1 2 250 >
每页显示 20 50 100
A Multi-dimensional Index Structure Based on Improved VA-file and CAN in the Cloud 被引量:2
1
作者 Chun-Ling Cheng Chun-Ju Sun +1 位作者 Xiao-Long Xu Deng-Yin Zhang 《International Journal of Automation and computing》 EI CSCD 2014年第1期109-117,共9页
Currently,the cloud computing systems use simple key-value data processing,which cannot support similarity search efectively due to lack of efcient index structures,and with the increase of dimensionality,the existing... Currently,the cloud computing systems use simple key-value data processing,which cannot support similarity search efectively due to lack of efcient index structures,and with the increase of dimensionality,the existing tree-like index structures could lead to the problem of"the curse of dimensionality".In this paper,a novel VF-CAN indexing scheme is proposed.VF-CAN integrates content addressable network(CAN)based routing protocol and the improved vector approximation fle(VA-fle) index.There are two index levels in this scheme:global index and local index.The local index VAK-fle is built for the data in each storage node.VAK-fle is thek-means clustering result of VA-fle approximation vectors according to their degree of proximity.Each cluster forms a separate local index fle and each fle stores the approximate vectors that are contained in the cluster.The vector of each cluster center is stored in the cluster center information fle of corresponding storage node.In the global index,storage nodes are organized into an overlay network CAN,and in order to reduce the cost of calculation,only clustering information of local index is issued to the entire overlay network through the CAN interface.The experimental results show that VF-CAN reduces the index storage space and improves query performance efectively. 展开更多
关键词 Cloud computing index similarity search clustering vector approximation fle(VA-fle) content addressable network(CAN)
原文传递
Application of multi-dimensional index matching in Pub/Sub system
2
作者 SONG Yu WU Yan QIAO Ling-ling 《通讯和计算机(中英文版)》 2009年第12期9-13,共5页
关键词 匹配算法 子系统 发布/订阅 酒吧 多维 应用 事件约束 相匹配
在线阅读 下载PDF
Composite anti-disturbance predictive control of unmanned systems with time-delay using multi-dimensional Taylor network 被引量:1
3
作者 Chenlong LI Wenshuo LI Zejun ZHANG 《Chinese Journal of Aeronautics》 2025年第7期589-600,共12页
A composite anti-disturbance predictive control strategy employing a Multi-dimensional Taylor Network(MTN)is presented for unmanned systems subject to time-delay and multi-source disturbances.First,the multi-source di... A composite anti-disturbance predictive control strategy employing a Multi-dimensional Taylor Network(MTN)is presented for unmanned systems subject to time-delay and multi-source disturbances.First,the multi-source disturbances are addressed according to their specific characteristics as follows:(A)an MTN data-driven model,which is used for uncertainty description,is designed accompanied with the mechanism model to represent the unmanned systems;(B)an adaptive MTN filter is used to remove the influence of the internal disturbance;(C)an MTN disturbance observer is constructed to estimate and compensate for the influence of the external disturbance;(D)the Extended Kalman Filter(EKF)algorithm is utilized as the learning mechanism for MTNs.Second,to address the time-delay effect,a recursiveτstep-ahead MTN predictive model is designed utilizing recursive technology,aiming to mitigate the impact of time-delay,and the EKF algorithm is employed as its learning mechanism.Then,the MTN predictive control law is designed based on the quadratic performance index.By implementing the proposed composite controller to unmanned systems,simultaneous feedforward compensation and feedback suppression to the multi-source disturbances are conducted.Finally,the convergence of the MTN and the stability of the closed-loop system are established utilizing the Lyapunov theorem.Two exemplary applications of unmanned systems involving unmanned vehicle and rigid spacecraft are presented to validate the effectiveness of the proposed approach. 展开更多
关键词 multi-dimensional Taylor network Composite anti-disturbance Predictive control Unmanned systems Multi-source disturbances TIME-DELAY
原文传递
Retraced Multi-dimensional Chinese Logic System behind Chinese Medicine
4
作者 Edwin C.L.Yu 《Chinese Medicine and Culture》 2025年第1期1-12,共12页
The ancient tacit knowledge behind the logic system permeated the culture and promoted numerous impactful inventions throughout the history. Traditional Chinese medicine with its effectiveness should also have stemmed... The ancient tacit knowledge behind the logic system permeated the culture and promoted numerous impactful inventions throughout the history. Traditional Chinese medicine with its effectiveness should also have stemmed out from such logic system. This article aims to rearticulate the underlying lucid multi-dimensional logic system, which faded in obscurity only because of time-out loss of the mid-right concept. Retracing this past tacit but important concept could uncover a multi-dimensional system over a point relating to all matters while capturing the central core of the matter. The seemingly unmanageable multidimensional logic was strengthened by verification processes which affirmed its further extensions, and made up the language of the people, the concepts of yin-yang(阴阳), and the development of extensions of Ba Gua(八卦) derivatives, which furthered the interpretation of the space-time properties and Chinese medicine. 展开更多
关键词 multi-dimensional logic system Traditional Chinese medicine YIN-YANG
暂未订购
Effective stress dissipation by multi-dimensional architecture engineering for ultrafast and ultralong sodium storage
5
作者 Man Zhang Jing Zhu +7 位作者 Qianqian Li Fenghua Zheng Sijiang Hu Youguo Huang Hongqiang Wang Xing Ou Qichang Pan Qingyu Li 《Journal of Energy Chemistry》 2025年第2期619-629,I0013,共12页
Stress accumulation is a key factor leading to sodium storage performance deterioration for NiSe_(2)-based anodes.Therefore,inhibiting the concentrated local stress during the sodiataion/desodiation process is crucial... Stress accumulation is a key factor leading to sodium storage performance deterioration for NiSe_(2)-based anodes.Therefore,inhibiting the concentrated local stress during the sodiataion/desodiation process is crucial for acquiring stable NiSe2-based materials for sodium-ion batteries(SIBs),Herein,a stress dissipation strategy driven by architecture engineering is proposed,which can achieve ultrafast and ultralong sodium storage properties.Different from the conventional sphere-like or rod-like architecture,the three-dimensional(3D)flower-like NiSe_(2)@C composite is delicately designed and assembled with onedimensional nanorods and carbon framework.More importantly,the fundamental mechanism of improved structure stability is unveiled by simulations and experimental results simultaneously.It demonstrates that this designed multidimensional flower-like architecture with dispersed nanorods can balance the structural mismatch,avoid concentrated local strain,and relax the internal stress,mainly induced by the unavoidable volume variation during the repeated conversion processes.Moreover,it can provide more Na^(+)-storage sites and multi-directional migration pathways,leading to a fast Na^(+)-migration channel with boosted reaction kinetic.As expected,it delivers superior rate performance(441 mA h g^(-1)at 5.0 A g^(-1))and long cycling stability(563 mA h g^(-1)at 1.0 A g^(-1)over 1000 cycles)for SIBs.This work provides useful insights for designing high-performance conversion-based anode materials for SIBs. 展开更多
关键词 Stress dissipation multi-dimensional architecture Structure engineering Conversion-based anodes Sodium-ion batteries
在线阅读 下载PDF
Research on Multi-Dimensional Collaborative Strategies in Design Management,Investment Management,and Beyond from the Perspective of Whole-Process Engineering Consulting
6
作者 Zexin Chen 《Journal of Architectural Research and Development》 2025年第5期21-28,共8页
This paper explores whole-process engineering consulting,including its application models in public buildings and elderly-friendly projects,such as service integration and whole lifecycle management.It also addresses ... This paper explores whole-process engineering consulting,including its application models in public buildings and elderly-friendly projects,such as service integration and whole lifecycle management.It also addresses the construction of multi-dimensional collaborative theoretical models,public space streamline organization,and other aspects,emphasizing the importance of multi-dimensional collaboration.Additionally,it highlights the role of talent cultivation and digital transformation in enhancing project efficiency. 展开更多
关键词 Whole-process engineering consulting multi-dimensional collaboration Project efficiency
在线阅读 下载PDF
Practical Application of the Multi-Dimensional Interactive Teaching Model in College English
7
作者 Bo Sun 《Journal of Contemporary Educational Research》 2025年第10期106-111,共6页
The multi-dimensional interactive teaching model significantly enhances the effectiveness of college English instruction by emphasizing dynamic engagement between teachers and students,as well as among students themse... The multi-dimensional interactive teaching model significantly enhances the effectiveness of college English instruction by emphasizing dynamic engagement between teachers and students,as well as among students themselves.This paper explores practical strategies for implementing this model,focusing on four key aspects:deepening teachers’understanding of the model through continuous learning,innovating interactive methods such as questioning techniques and practical activities,leveraging modern technology to integrate resources and track learning progress,and establishing a communication platform that centers on student participation.By adopting these approaches,the model fosters a student-centered classroom environment,improves comprehensive English application skills,and optimizes overall teaching quality. 展开更多
关键词 multi-dimensional interactive teaching model Student-centered approach Teacher-student interaction
在线阅读 下载PDF
Construction of the Practice System of Landscape Architecture Major Based on“Multi-dimensional Integration”
8
作者 LI Yinan DING Juan +4 位作者 ZHU Yan WU Jing ZHAO Zhiyan LI Jie XIANG Cheng 《Journal of Landscape Research》 2025年第3期89-92,共4页
During the critical transformation period of landscape architecture major after the adjustment of disciplinary structure and the changes in market demand,private colleges and universities,as important places for culti... During the critical transformation period of landscape architecture major after the adjustment of disciplinary structure and the changes in market demand,private colleges and universities,as important places for cultivating local talents,have pain points such as uneven quality of teachers and students and weak innovation and practice.The practice system with“multi-dimensional Integration”integrates four dimensions:interdisciplinary integration,spatial and temporal intersection,historical inheritance,and behavioral activity,deepens the disciplinary connotation,and integrates the three elements of nature,humanity,and technology,aiming to provide a new path for private colleges and universities to cultivate application-oriented and compound talents with innovative capabilities.In terms of optimizing talent cultivation and adapting to industry changes,this system provides thinking and reference for landscape architecture major,helping the major reshape its core competitiveness and promoting educational innovation and industry development. 展开更多
关键词 Landscape architecture Practice system multi-dimensional integration”model Talent cultivation Teaching reform
在线阅读 下载PDF
Reliability of multi-dimensional network systems with nodes having stochastic connection ranges
9
作者 FU Yuqiang MA Xiaoyang ZHAO Fei 《Journal of Systems Engineering and Electronics》 2025年第4期1017-1023,共7页
This paper proposes a reliability evaluation model for a multi-dimensional network system,which has potential to be applied to the internet of things or other practical networks.A multi-dimensional network system with... This paper proposes a reliability evaluation model for a multi-dimensional network system,which has potential to be applied to the internet of things or other practical networks.A multi-dimensional network system with one source element and multiple sink elements is considered first.Each element can con-nect with other elements within a stochastic connection ranges.The system is regarded as successful as long as the source ele-ment remains connected with all sink elements.An importance measure is proposed to evaluate the performance of non-source elements.Furthermore,to calculate the system reliability and the element importance measure,a multi-valued decision diagram based approach is structured and its complexity is analyzed.Finally,a numerical example about the signal transfer station system is illustrated to analyze the system reliability and the ele-ment importance measure. 展开更多
关键词 multi-dimensional network multi-valued decision diagram stochastic connection range reliability analysis impor-tance measure.
在线阅读 下载PDF
Multi-dimensional hydrogen bonds regulated emissions of single-molecule system enabling surficial hydrophobicity/hydrophilicity mapping
10
作者 Hao Gu Rui Li +6 位作者 Qiuying Li Sheng Lu Yahui Chen Xiaoning Yang Huili Ma Zhijun Xu Xiaoqiang Chen 《Chinese Chemical Letters》 2025年第5期515-520,共6页
Constructing multi-dimensional hydrogen bond(H-bond)regulated single-molecule systems with multiemission remains a challenge.Herein,we report the design of a new excited-state intramolecular proton transfer(ESIPT)feat... Constructing multi-dimensional hydrogen bond(H-bond)regulated single-molecule systems with multiemission remains a challenge.Herein,we report the design of a new excited-state intramolecular proton transfer(ESIPT)featured chromophore(HBT-DPI)that shows flexible emission tunability via the multidimensional regulation of intra-and intermolecular H-bonds.The feature of switchable intramolecular Hbonds is induced via incorporating several hydrogen bond acceptors and donors into one single HBT-DPI molecule,allowing the“turn on/off”of ESIPT process by forming isomers with distinct intramolecular Hbonds configurations.In response to different external H-bonding environments,the obtained four types of crystal/cocrystals vary in the contents of isomers and the molecular packing modes,which are mainly guided by the intermolecular H-bonds,exhibiting non-emissive features or emissions ranging from green to orange.Utilizing the feature of intermolecular H-bond guided molecular packing,we demonstrate the utility of this fluorescent material for visualizing hydrophobic/hydrophilic areas on large-scale heterogeneous surfaces of modified poly(1,1-difluoroethylene)(PVDF)membranes and quantitatively estimating the surface hydrophobicity,providing a new approach for hydrophobicity/hydrophilicity monitoring and measurement.Overall,this study represents a new design strategy for constructing multi-dimensional hydrogen bond regulated ESIPT-based fluorescent materials that enable multiple emissions and unique applications. 展开更多
关键词 multi-dimensional hydrogen bonds Emission regulation Hydrophobicity/hydrophilicity Surficial mapping Excited-state intramolecular proton transfer
原文传递
A novel multi-dimensional isolation platform for low-frequency excitations:analysis and experiment
11
作者 Lingjun MENG Xiuting SUN Jian XU 《Applied Mathematics and Mechanics(English Edition)》 2025年第12期2241-2264,共24页
To break the limitations of the multi-dimensional(M-D)vibration isolation(VI)platforms with the Stewart-Gough design,such as strongly coupling motions,excessive friction in connections,heavy weight,and limited workspa... To break the limitations of the multi-dimensional(M-D)vibration isolation(VI)platforms with the Stewart-Gough design,such as strongly coupling motions,excessive friction in connections,heavy weight,and limited workspace,this study processes a novel platform integrated by a stiffness-adjustable origami spring sub-structure and a parallel mechanism.The origami-based stiffness-adjustable spring realizes low-frequency VI,and the parallel mechanism symmetry design realizes motions decoupling.In the origami-based sub-leg,the parallel-stack-assembly(PSA)design mechanism with two Miura origami configurations is proposed to generate a symmetrical negative stiffness property.Paired with a linear positive stiffness spring,the origami-based sub-leg has wide-amplitude-high-static-low-dynamic stiffness(WA-HSLDS)characteristics in one direction.Then,with construction of the parallel mechanism connected with origami-based sub-legs,an M-D VI platform is achieved,whose motions in the vertical direction and yaw direction are decoupled with the motions in the other directions.Based on the dynamic model and incremental harmonic balance(IHB)with the arc-length continuation method,appropriate structural parameters in the parallel mechanism part are figured out,and the accurate transmissibility in different directions is defined,which gives the parametric influencing investigations for realization of low-frequency VI performances.Finally,experiments are conducted to validate the accuracy and feasibility of the theoretical methods,and to demonstrate the performance of M-D low-frequency isolation with load-carrying capacity of the proposed VI platform.The integration of the origami into the parallel mechanism results in a compact,efficient,and flexible platform with nonlinear adjustability,offering new possibilities for lightweight M-D VI,and developing the practical applications in high-precision platforms in ocean and aerospace environments. 展开更多
关键词 multi-dimensional(M-D)vibration isolation(VI) wide-amplitude high-static-low-dynamic stiffness(WA-HSLDS) origami-based elastic spring parallel mechanism
在线阅读 下载PDF
Vulnerability assessment in fractured aquifer using improved vulnerability index:Applied to Gabes aquifer,Southeastern Tunisia
12
作者 Mounir Atoui Belgacem Agoubi 《Journal of Groundwater Science and Engineering》 2026年第1期69-82,共14页
The Gabes aquifer system,located in southeastern Tunisia,is a crucial resource for supporting local socio-economic activities.Due to its dual porosity structure,is particularly vulnerable to pollution.This study aims ... The Gabes aquifer system,located in southeastern Tunisia,is a crucial resource for supporting local socio-economic activities.Due to its dual porosity structure,is particularly vulnerable to pollution.This study aims to develop a hybrid model that combines the Fracture Aquifer Index(FAI)with the conventional GOD(Groundwater occurrence,Overall lithology,Depth to water table)method,to assess groundwater vulnerability in fractured aquifer.To develop the hybrid model,the classical GOD method was integrated with FAI to produce a single composite index.Each parameter within both GOD and FAI was scored,and a final index was calculated to delineate vulnerable areas.The results show that the study area can be classified into four vulnerability levels:Very low,low,moderate,and high,indicating that approximately 8%of the area exhibits very low vulnerability,29%has low vulnerability,25%falls into the moderate category,and 38%is considered highly vulnerable.The FAI-GOD model further incorporates fracture network characteristics.This refinement reduces the classification to three vulnerability classes:Low,medium,and high.The outcomes demonstrate that 46%of the area is highly vulnerable due to a dense concentration of fractures,while 17%represents an intermediate zone characterized by either shallow or deeper fractures.In contrast,37%corresponds to areas with lightly fractured rock,where the impact on vulnerability is minimal.Multivariate statistical analysis was employed using Principal Components Analysis(PCA)and Hierarchical Cluster Analysis(HCA)on 24 samples across six variables.The first three components account for over 76%of the total variance,reinforcing the significance of fracture dynamics in classifying vulnerability levels.The FAI-GOD model removes the very-low-vulnerability class and expands the spatial extent of low-and high-vulnerability zones,reflecting the dominant influence of fracture networks on aquifer sensitivity.While both indices use a five-class system,FAI-GOD redistributes vulnerability by eliminating very-low-vulnerability areas and amplifying low/high categories,highlighting the critical role of fractures.A strong correlation(R2=0.94)between the GOD and FAI-GOD indices,demonstrated through second-order polynomial regression,confirms the robustness of the FAI-GOD model in accurately predicting vulnerability to pollution.This model provides a useful framework for assessing the vulnerability of complex aquifers and serves as a decision-making tool for groundwater managers in similar areas. 展开更多
关键词 GROUNDWATER Aquifer vulnerability Fractured media FAI-GOD index GOD index GIS
在线阅读 下载PDF
The triglyceride-glucose index shows promise as a novel prognostic marker for advanced hepatocellular carcinoma
13
作者 Tao Xu Xu Qi +1 位作者 Fei-Yu Zhao Nian-Song Qian 《World Journal of Gastroenterology》 2026年第2期167-169,共3页
This commentary critically appraises the study by Li et al which pioneered the exploration of the triglyceride-glucose(TyG)index as a prognostic marker in hepatitis B virus-related advanced hepatocellular carcinoma pa... This commentary critically appraises the study by Li et al which pioneered the exploration of the triglyceride-glucose(TyG)index as a prognostic marker in hepatitis B virus-related advanced hepatocellular carcinoma patients undergoing combined camrelizumab and lenvatinib therapy.While we acknowledge the study’s clinical relevance in proposing an easily accessible metabolic biomarker,we delve into the mechanistic plausibility linking insulin resistance to immunotherapy response and angiogenic inhibition.We further critically examine the methodological limitations,including the retrospective design,the populationspecific TyG cut-off value,and unaddressed metabolic confounders.We highlight the imperative for future research to validate its utility across diverse etiologies and treatment settings,and to unravel the underlying immunometabolic pathways. 展开更多
关键词 Triglyceride-glucose index Prognostic marker Advanced hepatocellular carcinoma Camrelizumab Lenvatinib
暂未订购
Construction of a mental health literacy evaluation index system for adolescents with mental disorders
14
作者 Ying-Qiong Ge Xiao-Shuang Ouyang +2 位作者 Zheng-Min Zhu Bi-Can Tan Xiao-Jian Jiang 《World Journal of Psychiatry》 2026年第1期299-311,共13页
BACKGROUND Timely and accurate evaluation of mental disorders in adolescents using appropriate mental health literacy assessment tools is essential for improving their mental health literacy levels.AIM To develop an e... BACKGROUND Timely and accurate evaluation of mental disorders in adolescents using appropriate mental health literacy assessment tools is essential for improving their mental health literacy levels.AIM To develop an evaluation index system for the mental health literacy of adolescent patients with mental disorders,providing a scientific,comprehensive,and reliable tool for the monitoring and intervention of mental health literacy of such patients.METHODS From December 2022 to June 2023,the evaluation index system for mental health literacy of adolescents with mental disorders was developed through literature reviews,semi-structured interviews,expert letter consultations,and the analytic hierarchy process.Based on this index system,a self-assessment questionnaire was compiled and administered to 305 adolescents with mental disorders to test the reliability and validity of the index system.RESULTS The final evaluation index system for mental health literacy of adolescents with mental disorders included 4 first-level indicators,10 second-level indicators,and 52 third-level indicators.The overall Cronbach’sαcoefficient of the index system was 0.957,with a partial reliability of 0.826 and a content validity index of 0.975.The cumulative variance contribution rate of 10 common factors was 66.491%.The correlation coefficients between each dimension and the total questionnaire ranged from 0.672 to 0.724,while the correlation coefficients in each dimension ranged from 0.389 to 0.705.CONCLUSION The evaluation index system for mental health literacy of adolescents with mental disorders,developed in this study,demonstrated notable reliability and validity,making it a valuable tool for evaluating mental health literacy in this population. 展开更多
关键词 Adolescents Mental disorders Mental health literacy Evaluation index system Delphi method
暂未订购
Multi-dimensional Analysis on Regional Land Use——Taking Bijie City as an Example
15
作者 陈笑筑 张定义 文兴耀 《Agricultural Science & Technology》 CAS 2016年第4期1002-1007,共6页
Based on the theory of information entropy, time series and spatial variation of land use changes of Bijie City in 2009-2013 were analyzed from different dimensions such as land use degree and land use diversity. The ... Based on the theory of information entropy, time series and spatial variation of land use changes of Bijie City in 2009-2013 were analyzed from different dimensions such as land use degree and land use diversity. The result showed that in 2009-2013, the forest vegetation was well protected, and the construction land was under reasonable expansion under the influence of economic development, the land use degree of which developed gradually to width and depth, and the trend of information entropy showed a graduate increase, indicating that land use scale became more reasonable and the area of different land type became more balanced in Bijie in the period. The study results showed that land resources in Bijie City were used rationally under the strategy from central government local government,and Bijie was in the benign development of economic development—resource distribution—scale change. Moreover, Bijie chould further improve land use pattern such as redevelop stock construction land, optimize the industrial land use pattern and mountain agricultural land development in the future. 展开更多
关键词 Land use Diversity index Information entropy Regional differences Dynamic changes
在线阅读 下载PDF
The Study on College English Writing Based on Multi-dimensional Feed-back Mode
16
作者 骆敏 徐敏娜 《海外英语》 2020年第12期273-274,共2页
The study constructed a multi-dimensional feedback mode integrating teacher feedback, peer feedback and network feedback, and applied it in the teaching of College English Writing. After 16 weeks of teaching, the stud... The study constructed a multi-dimensional feedback mode integrating teacher feedback, peer feedback and network feedback, and applied it in the teaching of College English Writing. After 16 weeks of teaching, the students in the multi-dimen-sional feedback class had significantly better overall writing scores than those in the teacher-feedback class. In terms of individual scores, multi-dimensional feedback played a better role in improving vocabulary and grammar than the class using teacher feed-back. However, there were no significant differences in the responses of writing tasks, coherence and cohesion. The study showed that most students were satisfied with the mode, believing that it was helpful to relieve writing anxiety, stimulate writing interest and improve their writing level. 展开更多
关键词 College English Writing multi-dimensional feedback MODE
在线阅读 下载PDF
Re-Establishing the Merits of Thermal Maturity and Petroleum Generation Multi-Dimensional Modeling with an Arrhenius Equation Using a Single Activation Energy 被引量:4
17
作者 David A.Wood 《Journal of Earth Science》 SCIE CAS CSCD 2017年第5期804-834,共31页
Thermal maturation and petroleum generation modeling of shales is essential for suc- cessful exploration and exploitation of conventional and unconventional oil and gas plays. For basin- wide unconventional resource p... Thermal maturation and petroleum generation modeling of shales is essential for suc- cessful exploration and exploitation of conventional and unconventional oil and gas plays. For basin- wide unconventional resource plays such modeling, when well calibrated with direct maturity meas- urements from wells, can characterize and locate production sweet spots for oil, wet gas and dry gas. The transformation of kerogen to petroleum is associated with many chemical reactions, but models typically focus on first-order reactions with rates determined by the Arrhenius Equation. A miscon- ception has been perpetuated for many years that accurate thermal maturity modeling of vitrinite re- flectance using the Arrhenius Equation and a single activation energy, to derive a time-temperature index (~TTIARa), as proposed by Wood (1988), is flawed. This claim was initially made by Sweeney and Burnham (1990) in promoting their "EasyRo" method, and repeated by others. This paper dem- onstrates through detailed multi-dimensional burial and thermal modeling and direct comparison of the ~TTIARR and "EasyRo" methods that this is not the case. The ~TTIA^R method not only provides a very useful and sensitive maturity index, it can reproduce the calculated vitrinite reflectance values derived from models based on multiple activation energies (e.g., "EasyRo"). Through simple expres- sions the ~TTIAaa method can also provide oil and gas transformation factors that can be flexibly scaled and calibrated to match the oil, wet gas and dry gas generation windows. This is achieved in a more-computationally-efficient, flexible and transparent way by the ~TTIARR method than the "EasyRo" method. Analysis indicates that the "EasyRo" method, using twenty activation energies and a constant frequency factor, generates reaction rates and transformation factors that do not realisti- cally model observed kerogen behaviour and transformation factors over geologic time scales. 展开更多
关键词 time-temperature maturity index kerogen activation energies kerogen reaction rates multi-dimensional thermal maturity models petroleum generation versus vitrinite reflectance burial/ thermal history analysis.
原文传递
Structural Engineering of Hierarchical Aerogels Comprised of Multi-dimensional Gradient Carbon Nanoarchitectures for Highly Efficient Microwave Absorption 被引量:19
18
作者 Yongpeng Zhao Xueqing Zuo +11 位作者 Yuan Guo Hui Huang Hao Zhang Ting Wang Ningxuan Wen Huan Chen Tianze Cong Javid Muhammad Xuan Yang Xinnan Wang Zeng Fan Lujun Pan 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第9期344-363,共20页
Recently,multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials.Nevertheless,excessive stack and agglomeration for low-dimension carbon nanomaterials inducing imped... Recently,multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials.Nevertheless,excessive stack and agglomeration for low-dimension carbon nanomaterials inducing impedance mismatch are significant challenges.Herein,the delicate“3D helix-2D sheet-1D fiber-0D dot”hierarchical aerogels have been successfully synthesized,for the first time,by sequential processes of hydrothermal self-assembly and in-situ chemical vapor deposition method.Particularly,the graphene sheets are uniformly intercalated by 3D helical carbon nanocoils,which give a feasible solution to the mentioned problem and endows the as-obtained aerogel with abundant porous structures and better dielectric properties.Moreover,by adjusting the content of 0D core-shell structured particles and the parameters for growth of the 1D carbon nanofibers,tunable electromagnetic properties and excellent impedance matching are achieved,which plays a vital role in the microwave absorption performance.As expected,the optimized aerogels harvest excellent performance,including broad effective bandwidth and strong reflection loss at low filling ratio and thin thickness.This work gives valuable guidance and inspiration for the design of hierarchical materials comprised of dimensional gradient structures,which holds great application potential for electromagnetic wave attenuation. 展开更多
关键词 Hierarchical aerogels multi-dimensional gradient Carbon nanocoils Microwave absorption
在线阅读 下载PDF
Seismic fragility analysis of highway bridges considering multi-dimensional performance limit state 被引量:17
19
作者 Wang, Qi'ang Wu, Ziyan Liu, Shukui 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2012年第2期185-193,共9页
Fragility analysis for highway bridges has become increasingly important in the risk assessment of highway transportation networks exposed to seismic hazards. This study introduces a methodology to calculate fragility... Fragility analysis for highway bridges has become increasingly important in the risk assessment of highway transportation networks exposed to seismic hazards. This study introduces a methodology to calculate fragility that considers multi-dimensional performance limit state parameters and makes a first attempt to develop fragility curves for a multi-span continuous (MSC) concrete girder bridge considering two performance limit state parameters: column ductility and transverse deformation in the abutments. The main purpose of this paper is to show that the performance limit states, which are compared with the seismic response parameters in the calculation of fragility, should be properly modeled as randomly interdependent variables instead of deterministic quantities. The sensitivity of fragility curves is also investigated when the dependency between the limit states is different. The results indicate that the proposed method can be used to describe the vulnerable behavior of bridges which are sensitive to multiple response parameters and that the fragility information generated by this method will be more reliable and likely to be implemented into transportation network loss estimation. 展开更多
关键词 highway bridge seismic hazard multi-dimensional performance limit state fragility curves sensitivity
在线阅读 下载PDF
Hydraulic directional valve fault diagnosis using a weighted adaptive fusion of multi-dimensional features of a multi-sensor 被引量:12
20
作者 Jin-chuan SHI Yan REN +1 位作者 He-sheng TANG Jia-wei XIANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2022年第4期257-271,共15页
Because the hydraulic directional valve usually works in a bad working environment and is disturbed by multi-factor noise,the traditional single sensor monitoring technology is difficult to use for an accurate diagnos... Because the hydraulic directional valve usually works in a bad working environment and is disturbed by multi-factor noise,the traditional single sensor monitoring technology is difficult to use for an accurate diagnosis of it.Therefore,a fault diagnosis method based on multi-sensor information fusion is proposed in this paper to reduce the inaccuracy and uncertainty of traditional single sensor information diagnosis technology and to realize accurate monitoring for the location or diagnosis of early faults in such valves in noisy environments.Firstly,the statistical features of signals collected by the multi-sensor are extracted and the depth features are obtained by a convolutional neural network(CNN)to form a complete and stable multi-dimensional feature set.Secondly,to obtain a weighted multi-dimensional feature set,the multi-dimensional feature sets of similar sensors are combined,and the entropy weight method is used to weight these features to reduce the interference of insensitive features.Finally,the attention mechanism is introduced to improve the dual-channel CNN,which is used to adaptively fuse the weighted multi-dimensional feature sets of heterogeneous sensors,to flexibly select heterogeneous sensor information so as to achieve an accurate diagnosis.Experimental results show that the weighted multi-dimensional feature set obtained by the proposed method has a high fault-representation ability and low information redundancy.It can diagnose simultaneously internal wear faults of the hydraulic directional valve and electromagnetic faults of actuators that are difficult to diagnose by traditional methods.This proposed method can achieve high fault-diagnosis accuracy under severe working conditions. 展开更多
关键词 Hydraulic directional valve Internal fault diagnosis Weighted multi-dimensional features Multi-sensor information fusion
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部