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Scavenging Microwave Wireless Power:A Unified Model,Rectenna Design Automation,and Cutting-Edge Techniques
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作者 Si-Ping Gao Jun-Hui Ou +1 位作者 Xiuyin Zhang Yongxin Guo 《Engineering》 SCIE EI CAS CSCD 2023年第11期32-48,共17页
While sufficient review articles exist on inductive short-range wireless power transfer(WPT),long-haul microwave WPT(MWPT)for solar power satellites,and ambient microwave wireless energy harvesting(MWEH)in urban areas... While sufficient review articles exist on inductive short-range wireless power transfer(WPT),long-haul microwave WPT(MWPT)for solar power satellites,and ambient microwave wireless energy harvesting(MWEH)in urban areas,few studies focus on the fundamental modeling and related design automation of receiver systems.This article reviews the development of MWPT and MWEH receivers,with a focus on rectenna design automation.A novel rectifier model capable of accurately modeling the rectification process under both high and low input power is presented.The model reveals the theoretical boundary of radio frequency-to-direct current(dc)power conversion efficiency and,most importantly,enables an automated system design.The automated rectenna design flow is sequential,with the minimal engagement of iterative optimization.It covers the design automation of every module(i.e.,rectifiers,matching circuits,antennae,and dc–dc converters).Scaling-up of the technique to large rectenna arrays is also possible,where the challenges in array partitioning and power combining are briefly discussed.In addition,several cutting-edge rectenna techniques for MWPT and MWEH are reviewed,including the dynamic range extension technique,the harmonics-based retro-directive technique,and the simultaneous wireless information and power transfer technique,which can be good complements to the presented automated design methodology. 展开更多
关键词 Microwave wireless power transfer Microwave wireless energy harvesting unified Rectifier model Automated rectenna design Emerging rectenna techniques
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A unified model for the formation and distribution of both conventional and unconventional hydrocarbon reservoirs 被引量:13
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作者 Xiongqi Pang Chengzao Jia +8 位作者 Junqing Chen Maowen Li Wenyang Wang Qinhong Hu Yingchun Guo Zhangxin Chen Junwen Peng Keyu Liu Keliu Wu 《Geoscience Frontiers》 SCIE CAS CSCD 2021年第2期695-711,共17页
The discovery and large-scale exploration of unconventional oil/gas resources since 1980s have been considered as the most important advancement in the history of petroleum geology;that has not only changed the balanc... The discovery and large-scale exploration of unconventional oil/gas resources since 1980s have been considered as the most important advancement in the history of petroleum geology;that has not only changed the balance of supply and demand in the global energy market,but also improved our understanding of the formation mechanisms and distribution characteristics of oil/gas reservoirs.However,what is the difference of conventional and unconventional resources and why they always related to each other in petroliferous basins is not clear.As the differences and correlations between unconventional and conventional resources are complex challenging issues and very critical for resources assessment and hydrocarbon exploration,this paper focused on studying the relationship of formations and distributions among different oil/gas reservoirs.Drilling results of 12,237 exploratory wells in 6 representative petroliferous basins of China and distribution characteristics for 52,926 oil/gas accumulations over the world were applied to clarify the formation conditions and genetic relations of different oil/gas reservoirs in a petroliferous basin,and then to establish a unified model to address the differences and correlations of conventional and unconventional reservoirs.In this model,conventional reservoirs formed in free hydrocarbon dynamic field with high porosity and permeability located above the boundary of hydrocarbon buoyancy-driven accumulation depth limit.Unconventional tight reservoirs formed in confined hydrocarbon dynamic field with low porosity and permeability located between hydrocarbon buoyancy-driven accumulation depth limit and hydrocarbon accumulation depth limit.Shale oil/gas reservoirs formed in the bound hydrocarbon dynamic field with low porosity and ultra-low permeability within the source rock layers.More than 75%of proved reserves around the world are discovered in the free hydrocarbon dynamic field,which is estimated to contain only 10%of originally generated hydrocarbons.Most of undiscovered resources distributed in the confined hydrocarbon dynamic field and the bound hydrocarbon dynamic field,which contains 90%of original generated hydrocarbons,implying a reasonable and promising area for future hydrocarbon explorations.The buried depths of hydrocarbon dynamic fields become shallow with the increase of heat flow,and the remaining oil/gas resources mainly exist in the deep area of“cold basin”with low geothermal gradient.Lithology changing in the hydrocarbon dynamic field causes local anomalies in the oil/gas dynamic mechanism,leading to the local formation of unconventional hydrocarbon reservoirs in the free hydrocarbon dynamic field or the occurrence of oil/gas enrichment sweet points with high porosity and permeability in the confined hydrocarbon dynamic field.The tectonic movements destroy the medium conditions and oil/gas components,which leads to the transformation of conventional oil/gas reservoirs formed in free hydrocarbon dynamic field to unconventional ones or unconventional ones formed in confined and bound hydrocarbon dynamic fields to conventional ones. 展开更多
关键词 Fossil fuels Hydrocarbon resources unified model of reservoirs formation Hydrocarbon reservoirs Hydrocarbon accumulation Hydrocarbon dynamic field
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Evaluation of Unified Model Microphysics in High-resolution NWP Simulations Using Polarimetric Radar Observations 被引量:1
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作者 Marcus JOHNSON Youngsun JUNG +4 位作者 Daniel DAWSON Timothy SUPINIE Ming XUE Jongsook PARK Yong-Hee LEE 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2018年第7期771-784,共14页
The UK Met Office Unified Model(UM) is employed by many weather forecasting agencies around the globe. This model is designed to run across spatial and time scales and known to produce skillful predictions for large... The UK Met Office Unified Model(UM) is employed by many weather forecasting agencies around the globe. This model is designed to run across spatial and time scales and known to produce skillful predictions for large-scale weather systems. However, the model has only recently begun running operationally at horizontal grid spacings of ~1.5 km [e.g.,at the UK Met Office and the Korea Meteorological Administration(KMA)]. As its microphysics scheme was originally designed and tuned for large-scale precipitation systems, we investigate the performance of UM microphysics to determine potential inherent biases or weaknesses. Two rainfall cases from the KMA forecasting system are considered in this study: a Changma(quasi-stationary) front, and Typhoon Sanba(2012). The UM output is compared to polarimetric radar observations in terms of simulated polarimetric radar variables. Results show that the UM generally underpredicts median reflectivity in stratiform rain, producing high reflectivity cores and precipitation gaps between them. This is partially due to the diagnostic rain intercept parameter formulation used in the one-moment microphysics scheme. Model drop size is generally both underand overpredicted compared to observations. UM frozen hydrometeors favor generic ice(crystals and snow) rather than graupel, which is reasonable for Changma and typhoon cases. The model performed best with the typhoon case in terms of simulated precipitation coverage. 展开更多
关键词 unified model MICROPHYSICS polarimetric radar radar simulator numerical weather prediction
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Properties of Optical and X-ray Selected AGN-Probing the Unified Model of AGN
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作者 Karsten Bischoff 《天文研究与技术》 CSCD 北大核心 2003年第S1期74-77,共4页
We have compiled a sample of two subsets of AGN selected from their optical and X ray data. The first subset was selected for very broad and/or peculiar optical emission line profiles, the second for a high X ray flux... We have compiled a sample of two subsets of AGN selected from their optical and X ray data. The first subset was selected for very broad and/or peculiar optical emission line profiles, the second for a high X ray flux. Here we will discuss properties of these galaxies and show that both subsets are very similar in the multi wavelength view. Furthermore, we will discuss differences between the two subsets and their implications for a Unified Model of AGN. 展开更多
关键词 Properties of Optical and X-ray Selected AGN-Probing the unified model of AGN Figure FWHM of
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BL Lac Objects and Unified Model
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作者 Fan J.H. (Yunnan Observatory, The Chinese Academy of Sciences, Kunming 650011, China) (National Astronomical Observatories, The Chinese Academy of Sciences) (Center for Astrophysics, Guangzhou Normal University, Guangzhou 510400, China e mail: jhfan@g 《天文研究与技术》 CSCD 1999年第S1期210-212,共3页
In this paper: 1. The assumption of the dependence of Doppler factor on the emission frequency (δ v≈δ 0 18logvv o , Fan et al. 1993, ApJ., 415, 113) is used to explain the observational differences between the radi... In this paper: 1. The assumption of the dependence of Doppler factor on the emission frequency (δ v≈δ 0 18logvv o , Fan et al. 1993, ApJ., 415, 113) is used to explain the observational differences between the radio selected BL Lac objects (RBLs) and the X Ray Selected BL lac objects (XBLs): a) Hubble relation; b) different multiwavelength correlations; c) different regions in the effective spectral index (α RO - α OX ) diagram; d) different polarization. The results suggest that RBLs and XBLs are the same. 2. From the analysis of the relation between infrared magnitude and redshift, it is proposed that the parent population of BL Lac objects should be FRI radio galaxies and FRII(G) radio galaxies showing the optical spectra of a galaxy. 3. From the superluminal motion, the assumption (δ v≈δ 0 18+logvv 0 ) is confirmed. 4. Based on the relation between polarization and Doppler factor (Fan et al. 1997a), it is proposed that the f, ratio of the beamed luminosity to the unbeamed luminosity in the source frame of OVVs/HPQs is smaller than that of BL Lac objects: f RBLs ~ 6f FSRQs . 展开更多
关键词 BL Lac Objects and unified model
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Autonomous relative optical navigation based on unified modeling of external systematic errors
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作者 Dayi WANG Bowen SUN +2 位作者 Maodeng LI Jiaxing LI Haiyin ZHOU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第3期282-289,共8页
To solve the problem that external systematic errors of the optical camera cannot be fully estimated due to limited computing resources,a unified dimensionality reduction representation method for the external systema... To solve the problem that external systematic errors of the optical camera cannot be fully estimated due to limited computing resources,a unified dimensionality reduction representation method for the external systematic errors of the optical camera is proposed,and autonomous relative optical navigation is realized.The camera translational and misalignment errors are converted into a three-dimensional rotation error,whose differential model can be established through specific attitude control and appropriate assumption.Then,the rotation error and the relative motion state are jointly estimated in an augmented Kalman filter framework.Compared with the traditional method that estimates the camera translational and misalignment errors,the proposed method reduces the computational complexity in that the estimated state dimension is reduced.Furthermore,as demonstrated by numerical simulation,the estimation accuracy is improved significantly. 展开更多
关键词 unified model Systematic errors Optical navigation Observability analysis CALIBRATION
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Unified deep learning model for predicting fundus fluorescein angiography image from fundus structure image
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作者 Yiwei Chen Yi He +3 位作者 Hong Ye Lina Xing Xin Zhang Guohua Shi 《Journal of Innovative Optical Health Sciences》 SCIE EI CSCD 2024年第3期105-113,共9页
The prediction of fundus fluorescein angiography(FFA)images from fundus structural images is a cutting-edge research topic in ophthalmological image processing.Prediction comprises estimating FFA from fundus camera im... The prediction of fundus fluorescein angiography(FFA)images from fundus structural images is a cutting-edge research topic in ophthalmological image processing.Prediction comprises estimating FFA from fundus camera imaging,single-phase FFA from scanning laser ophthalmoscopy(SLO),and three-phase FFA also from SLO.Although many deep learning models are available,a single model can only perform one or two of these prediction tasks.To accomplish three prediction tasks using a unified method,we propose a unified deep learning model for predicting FFA images from fundus structure images using a supervised generative adversarial network.The three prediction tasks are processed as follows:data preparation,network training under FFA supervision,and FFA image prediction from fundus structure images on a test set.By comparing the FFA images predicted by our model,pix2pix,and CycleGAN,we demonstrate the remarkable progress achieved by our proposal.The high performance of our model is validated in terms of the peak signal-to-noise ratio,structural similarity index,and mean squared error. 展开更多
关键词 Fundus fluorescein angiography image fundus structure image image translation unified deep learning model generative adversarial networks
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Unified Model in Identity Subspace for Face Recognition 被引量:2
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作者 PinLiao LiShen +1 位作者 Yi-QiangChen Shu-ChangLiu 《Journal of Computer Science & Technology》 SCIE EI CSCD 2004年第5期684-690,共7页
Human faces have two important characteristics: (1) They are similar objectsand the specific variations of each face are similar to each other; (2) They are nearly bilateralsymmetric. Exploiting the two important prop... Human faces have two important characteristics: (1) They are similar objectsand the specific variations of each face are similar to each other; (2) They are nearly bilateralsymmetric. Exploiting the two important properties, we build a unified model in identity subspace(UMIS) as a novel technique for face recognition from only one example image per person. An identitysubspace spanned by bilateral symmetric bases, which compactly encodes identity information, ispresented. The unified model, trained on an obtained training set with multiple samples per classfrom a known people group A, can be generalized well to facial images of unknown individuals, andcan be used to recognize facial images from an unknown people group B with only one sample persubject, Extensive experimental results on two public databases (the Yale database and the Berndatabase) and our own database (the ICT-JDL database) demonstrate that the UMIS approach issignificantly effective and robust for face recognition. 展开更多
关键词 pattern recognition face recognition identity subspace unified model
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Validation of static properties in unified modeling language models for cyber physical systems 被引量:2
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作者 Gabriela MAGUREANU Madalin GAVRILESCU Dan PESCARU 《Journal of Zhejiang University-Science C(Computers and Electronics)》 SCIE EI 2013年第5期332-346,共15页
Cyber physical systems (CPSs) can be found nowadays in various fields of activity. The increased interest for these systems as evidenced by the large number of applications led to complex research regarding the most s... Cyber physical systems (CPSs) can be found nowadays in various fields of activity. The increased interest for these systems as evidenced by the large number of applications led to complex research regarding the most suitable methods for design and development. A promising solution for specification, visualization, and documentation of CPSs uses the Object Management Group (OMG) unified modeling language (UML). UML models allow an intuitive approach for embedded systems design, helping end-users to specify the requirements. However, the UML models are represented in an informal language. Therefore, it is difficult to verify the correctness and completeness of a system design. The object constraint language (OCL) was defined to add constraints to UML, but it is deficient in strict notations of mathematics and logic that permits rigorous analysis and reasoning about the specifications. In this paper, we investigated how CPS applications modeled using UML deployment diagrams could be formally expressed and verified. We used Z language constructs and prototype verification system (PVS) as formal verification tools. Considering some relevant case studies presented in the literature, we investigated the opportunity of using this approach for validation of static properties in CPS UML models. 展开更多
关键词 Cyber physical system (CPS) unified modeling language (UML) design Formal verification Prototype verification system (PVS) Z language
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A unified model with a generalized gauge symmetry and its cosmological implications
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作者 Jong-Ping Hsu Kazuo O.Cottrell 《Chinese Physics C》 SCIE CAS CSCD 2015年第10期68-76,共9页
A unified model is based on a generalized gauge symmetry with groups [Sg3c]color×(SU2×U1)X[U1b×U11]. It implies that all interactions should preserve conservation laws of baryon number, lepton number,... A unified model is based on a generalized gauge symmetry with groups [Sg3c]color×(SU2×U1)X[U1b×U11]. It implies that all interactions should preserve conservation laws of baryon number, lepton number, and electric charge, etc. The baryonie U1b, leptonie U11 and color SU3o gauge transformations are generalized to involve nonintegrable phase factors. One has gauge invariant fourth-order equations for massless gauge fields, which leads to linear potentials in the [U1b × U11] and color [SUao] sectors. We discuss possible cosmological implications of the new baryonie gauge field. It can produce a very small constant repulsive force between two baryon galaxies (or between two anti-baryon galaxies), where the baryon force can overcome the gravitational force at very large distances and leads to an accelerated cosmic expansion. Based on conservation laws in the unified model, we discuss a simple rotating dumbbell universe with equal amounts of matter and anti-matter, which may be pictured as two gigantic rotating clusters of galaxies. Within the gigantic baryonie cluster, a galaxy will have an approximately linearly accelerated expansion due to the effective force of constant density of all baryonie matter. The same expansion happens in the gigantic anti-baryonic cluster. Physical implications of the generalized gauge symmetry on charmonium confining potentials due to new SUac field equations, frequency shift of distant supernovae Ia and their experimental tests are discussed. 展开更多
关键词 unified model nonintegrable phase factors conservation laws COSMOLOGY accelerated expansion
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A UNIFIED RETENTION MODEL OF SOLUTE IN LIQUID CHROMATOGRAPHY 被引量:3
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作者 Xin Du GENG Liu Jiao BIAN Laboratory of Modern Separation Science,Department of Chemistry Northwest University,Xi’an 710069 《Chinese Chemical Letters》 SCIE CAS CSCD 1990年第2期135-138,共4页
Based on six thermodynamic equilibria,a unified retention model of solute in liquid chromatography(LC)is first proposed.The unified model was tested and proved to be valid for a LC sys- tem with mobile phase consistin... Based on six thermodynamic equilibria,a unified retention model of solute in liquid chromatography(LC)is first proposed.The unified model was tested and proved to be valid for a LC sys- tem with mobile phase consisting of a complete range of multiple,ternary or binary components and each kind of LC except size exclusion chromatography.In addition,so long as making some assumptions and mathematical conversions,the expressions of various popular models in LC can be derived by using the unified model. 展开更多
关键词 A unified RETENTION model OF SOLUTE IN LIQUID CHROMATOGRAPHY
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Unified Data Model of Urban Air Pollution Dispersion and 3D Spatial City Model:Groundwork Assessment towards Sustainable Urban Development for Malaysia 被引量:2
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作者 Uznir Ujang Francois Anton Alias Abdul Rahman 《Journal of Environmental Protection》 2013年第7期701-712,共12页
Understanding the behavior of urban air pollution is important en route for sustainable urban development (SUD). Malaysia is on its mission to be a developed country by year 2020 comprehends dealing with air pollution... Understanding the behavior of urban air pollution is important en route for sustainable urban development (SUD). Malaysia is on its mission to be a developed country by year 2020 comprehends dealing with air pollution is one of the indicators headed towards it. At present monitoring and managing air pollution in urban areas encompasses sophisticated air quality modeling and data acquisition. However, rapid developments in major cities cause difficulties in acquiring the city geometries. The existing method in acquiring city geometries data via ground or space measurement inspection such as field survey, photogrammetry, laser scanning, remote sensing or using architectural plans appears not to be practical because of its cost and efforts. Moreover, air monitoring stations deployed are intended for regional to global scale model whereby it is not accurate for urban areas with typical resolution of less than 2 km. Furthermore in urban areas, the pollutant dispersion movements are trapped between buildings initiating it to move vertically causing visualization complications which imply the limitations of existing visualization scheme that is based on two-dimensional (2D) framework. Therefore this paper aims is to perform groundwork assessment and discuss on the current scenario in Malaysia in the aspect of current policies towards SUD, air quality monitoring stations, scale model and detail discussion on air pollution dispersion model used called the Operational Street Pollution Model (OSPM). This research proposed the implementation of three-dimensional (3D) spatial city model as a new physical data input for OSPM. The five Level of Details (LOD) of 3D spatial city model shows the scale applicability for the dispersion model implementtation. Subsequently 3D spatial city model data commonly available on the web, by having a unified data model shows the advantages in easy data acquisition, 3D visualization of air pollution dispersion and improves visual analysis of air quality monitoring in urban areas. 展开更多
关键词 3D Spatial City model Urban Air Dispersion model unified Data model Sustainable Urban Development CITYGML 3D Visualization 3D GIS
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Unified Coordinate System Model for Performance Calculation of Fix-pad Journal Bearing with Different Pad Preload
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作者 ZHU Aibin YANG Yulei +1 位作者 CHEN Wei YUAN Xiaoyang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第3期537-542,共6页
Traditional model for calculating performance parameters of a fix-pad journal bearing leads to heavy workload, complicated and changeable formulae as it requires deriving various geometric formulae with different bear... Traditional model for calculating performance parameters of a fix-pad journal bearing leads to heavy workload, complicated and changeable formulae as it requires deriving various geometric formulae with different bearing types such as circular journal bearing, dislocated bearing and elliptic bearing. Considering different pad preload ratios for non-standard bearing, traditional model not only becomes more complicated but also reduces scalability and promotion of the calculation programs. For the complexly case of traditional model while dealing with various fix-pad journal bearings, unified coordinate system model for performance calculation of fix-pad journal bearing is presented in the paper. A unified coordinate system with the bearing center at the origin is established, and the eccentricity ratio and attitude angle of axis relative to each pad are calculated through the coordinates of journal center and each pad center. Geometric description of fix-pad journal bearing is unified in this model, which can be used for both various standard bearing and non-standard bearing with different pad preload ratios. Validity of this model is verified with an elliptical bearing. Performance of a non-standard four-leaf bearing with different pad preload ratios is calculated based on this model. The calculation result shows that increasing preload ratio of the pad 1 and keeping that of the left three pads constant improves bearing capacity, stiffness and damping coefficients. This research presents a unified coordinate system model unifies performance calculation of fix-pad journal bearings and studied a non-standard four-leaf bearing with different pad preload ratios, the research conclusions provides new methods for performance calculation of fix-pad journal bearings. 展开更多
关键词 fix-pad journal bearing performance calculation unified coordinate system model
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A Fuzzy Set-Based Approach for Model-Based Internet-Banking System Security Risk Assessment 被引量:3
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作者 LI Hetian LIU Yun HE Dequan 《Wuhan University Journal of Natural Sciences》 CAS 2006年第6期1869-1872,共4页
A fuzzy set-based evaluation approach is demonstrated to assess the security risks for internet-banking System. The Internet-banking system is semi-formally described using Unified Modeling Language (UML) to specify... A fuzzy set-based evaluation approach is demonstrated to assess the security risks for internet-banking System. The Internet-banking system is semi-formally described using Unified Modeling Language (UML) to specify the behavior and state of the system on the base of analyzing the existing qualitative risk assessment methods. And a quantitative method based on fuzzy set is used to measure security risks of the system, A case study was performed on the WEB server of the Internet-banking System using fuzzy-set based assessment algorithm to quantitatively compute the security risk severity. The numeric result also provides a method to decide the most critical component which should amuse the system administrator enough attention to take the appropriate security measure or controls to alleviate the risk severity. The experiments show this method can be used to quantify the security properties for the Internet-banking System in practice. 展开更多
关键词 risk assessment system security fuzzy set unified modeling language
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Capability requirements modeling and verification based on fuzzy ontology 被引量:3
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作者 Qingchao Dong Zhixue Wang Weixing Zhu Hongyue He 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第1期78-87,共10页
The capability requirements of the command, control, communication, computing, intelligence, surveillance, reconnaissance (C41SR) systems are full of uncertain and vague information, which makes it difficult to mode... The capability requirements of the command, control, communication, computing, intelligence, surveillance, reconnaissance (C41SR) systems are full of uncertain and vague information, which makes it difficult to model the C41SR architecture. The paper presents an approach to modeling the capability requirements with the fuzzy unified modeling language (UML) and building domain ontologies with fuzzy description logic (DL). The UML modeling constructs are extended according to the meta model of Depart- ment of Defense Architecture Framework to improve their domain applicability, the fuzzy modeling mechanism is introduced to model the fuzzy efficiency features of capabilities, and the capability requirement models are converted into ontologies formalized in fuzzy DL so that the model consistency and reasonability can be checked with a DL reasoning system. Finally, a case study of C41SR capability requirements model checking is provided to demonstrate the availability and applicability of the method. 展开更多
关键词 fuzzy ontology fuzzy unified modeling language (UML) fuzzy description logic (DL) model checking.
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Formalization and Verification of Business Process Modeling Based on UML and Petri Nets 被引量:1
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作者 颜志军 甘仞初 《Journal of Beijing Institute of Technology》 EI CAS 2005年第2期212-216,共5页
In order to provide a quantitative analysis and verification method for activity diagrams based business process modeling, a formal definition of activity diagrams is introduced. And the basic requirements for activit... In order to provide a quantitative analysis and verification method for activity diagrams based business process modeling, a formal definition of activity diagrams is introduced. And the basic requirements for activity diagrams based business process models are proposed. Furthermore, the standardized transformation technique between business process models and basic Petri nets is presented and the analysis method for the soundness and well-structured properties of business processes is introduced. 展开更多
关键词 business process modeling unified modeling language(UML) Petri nets activity diagram
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Decouple charge transfer reactions in the Li-ion battery
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作者 Yuxuan Bai Qiu-An Huang +1 位作者 Kai Wu Jiujun Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期759-798,共40页
In the development of Li-ion batteries(LIBs)with high energy/power density,long cycle-life,fast charging,and high safety,an insight into charge transfer reactions is required.Although electrochemical impedance spectro... In the development of Li-ion batteries(LIBs)with high energy/power density,long cycle-life,fast charging,and high safety,an insight into charge transfer reactions is required.Although electrochemical impedance spectroscopy(EIS)is regarded as a powerful diagnosis tool,it is not a direct but an indirect measurement.With respect to this,some critical questions need to be answered:(i)why EIS can reflect the kinetics of charge transfer reactions;(ii)what the inherent logical relationship between impedance models under different physical scenes is;(iii)how charge transfer reactions compete with each other at multiple scales.This work aims at answering these questions via developing a theory framework so as to mitigate the blindness and uncertainty in unveiling charge transfer reactions in LIBs.To systematically answer the above questions,this article is organized into a three-in-one(review,tutorial,and research)type and the following contributions are made:(i)a brief review is given for impedance model development of the LIBs over the past half century;(ii)an open source code toolbox is developed based on the unified impedance model;(iii)the competive mechanisms of charge transfer reactions are unveiled based on the developed EIS-Toolbox@LIB.This work not only clarifies theoretical fundamentals,but also provides an easy-to-use open source code for EIS-Toolbox@LIB to optimize fast charge/discharge,mitigate cycle aging,and improve energy/power density. 展开更多
关键词 Electrochemical impedance spectroscopy unified impedance model Charge transfer reactions Solid/electrolyte diffusion Porous electrode EIS-Toolbox@LIB
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MODELING OF FMS BASED ON UML AND OPNS
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作者 Gao Meimei Wu Zhiming (Department of Automation, Shanghai Jiaotong University) 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2000年第2期90-95,共6页
As the main component of computer integrated manufacturing system (CIMS), flexible manufacturing system (FMS) should be an open system with reusability and extenchaility. Moreover, as FMS is a complex asynchronous con... As the main component of computer integrated manufacturing system (CIMS), flexible manufacturing system (FMS) should be an open system with reusability and extenchaility. Moreover, as FMS is a complex asynchronous concurrent system, its model also should have the abilities to express the concurrency in the system and to analyze the behavior of the system. It is difficult to use any one method to model such a complex system as FMS. A modeling method using Object-oriented modeling language-unified modeling language (UML) and object-Oriented Petri nets (OPNs) is proposed. Class diagram in UML is used to represent the static relations among the objects in FMS. OPNs are used to model the dynamic behavior of the objects and conduct performance analysis. OPNs also can be used to identify the attributes and operations of the objects. The model can describe the system integrally and can be used to design FMS control software naturally. 展开更多
关键词 Flexible manufacturing system modeling Object-oriented model unified modeling language Object-oriented Pert nets (Opens)
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Direct modeling for computational fluid dynamics 被引量:3
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作者 Kun Xu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第3期303-318,共16页
All fluid dynamic equations are valid under their modeling scales, such as the particle mean free path and mean collision time scale of the Boltzmann equation and the hydrodynamic scale of the Navier-Stokes (NS) equ... All fluid dynamic equations are valid under their modeling scales, such as the particle mean free path and mean collision time scale of the Boltzmann equation and the hydrodynamic scale of the Navier-Stokes (NS) equations. The current computational fluid dynamics (CFD) focuses on the numerical solution of partial differential equations (PDEs), and its aim is to get the accurate solution of these governing equations. Under such a CFD practice, it is hard to develop a unified scheme that covers flow physics from kinetic to hydrodynamic scales continuously because there is no such governing equation which could make a smooth transition from the Boltzmann to the NS modeling. The study of fluid dynamics needs to go beyond the traditional numer- ical partial differential equations. The emerging engineering applications, such as air-vehicle design for near-space flight and flow and heat transfer in micro-devices, do require fur- ther expansion of the concept of gas dynamics to a larger domain of physical reality, rather than the traditional dis- tinguishable governing equations. At the current stage, the non-equilibrium flow physics has not yet been well explored or clearly understood due to the lack of appropriate tools. Unfortunately, under the current numerical PDE approach, it is hard to develop such a meaningful tool due to the absence of valid PDEs. In order to construct multiscale and multiphysics simulation methods similar to the modeling process of con- structing the Boltzmann or the NS governing equations, the development of a numerical algorithm should be based on the first principle of physical modeling. In this paper, instead of following the traditional numerical PDE path, we introduce direct modeling as a principle for CFD algorithm develop- ment. Since all computations are conducted in a discretized space with limited cell resolution, the flow physics to be mod- eled has to be done in the mesh size and time step scales. Here, the CFD is more or less a direct construction of dis- crete numerical evolution equations, where the mesh size and time step will play dynamic roles in the modeling process. With the variation of the ratio between mesh size and local particle mean free path, the scheme will capture flow physics from the kinetic particle transport and collision to the hydro- dynamic wave propagation. Based on the direct modeling, a continuous dynamics of flow motion will be captured in the unified gas-kinetic scheme. This scheme can be faithfully used to study the unexplored non-equilibrium flow physics in the transition regime. 展开更多
关键词 Direct modeling unified gas kinetic schemeBoltzmann equation - Kinetic collision model Non-equilibrium flows Navier-Stokes equations
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Foundations of Programmable Process Structures for the unified modeling and simulation of agricultural and aquacultural systems
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作者 Monika Varga Bela Csukas 《Information Processing in Agriculture》 EI 2024年第1期91-108,共18页
This research paper defines the theoretical foundations and computational implementation of a non-conventional modeling and simulation methodology,inspired by the needs of problem solving for biological,agricultural,a... This research paper defines the theoretical foundations and computational implementation of a non-conventional modeling and simulation methodology,inspired by the needs of problem solving for biological,agricultural,aquacultural and environmental systems.The challenging practical problem is to develop a framework for automatic generation of causally right and balance-based,unified models that can also be applied for the effective coupling amongst the various(sophisticated field-specific,sensor data processing-based,upper level optimization-driven,etc.)models.The scientific problem addressed in this innovation is to develop Programmable Process Structures(PPS)by combining functional basis of systems theory,structural approach of net theory and computational principles of agent based modeling.PPS offers a novel framework for the automatic generation of easily extensible and connectible,unified models for the underlying complex systems.PPS models can be generated from one state and one transition meta-prototypes and from the transition oriented description of process structure.The models consist of unified state and transition elements.The local program containing prototype elements,derived also from the meta-prototypes,are responsible for the case-specific calculations.The integrity and consistency of PPS architecture are based on the meta-prototypes,prepared to distinguish between the conservation-laws-based measures and the signals.The simulation is based on data flows amongst the state and transition elements,as well as on the unification based data transfer between these elements and their calculating prototypes.This architecture and its AI language-based(Prolog)implementation support the integration of various field-and task-specific models,conveniently.The better understanding is helped by a simple example.The capabilities of the recently consolidated general methodology are discussed on the basis of some preliminary applications,focusing on the recently studied agricultural and aquacultural cases. 展开更多
关键词 unified process model Meta-prototype-based architecture Transition-based structure representation Locally programmable functionality prototypes Agricultural systems Aquacultural systems
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