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Comparative Study of the Socioeconomic Characteristics and Digital Literacy Level of Agricultural Extension Personnel in Imo and Ebonyi States, South-East, Nigeria
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作者 Ogbonnaya Okoro Aja Cyril Chigozie Asiabaka +1 位作者 Anthony Okorie Ani Edna Chioma Matthews-Njoku 《Agricultural Sciences》 2024年第2期230-245,共16页
The study comparatively analysed the socioeconomic characteristics and digital literacy level of Agricultural Extension personnel (AEP) in Ebonyi and Imo States, South-East, Nigeria. The specific objectives were to de... The study comparatively analysed the socioeconomic characteristics and digital literacy level of Agricultural Extension personnel (AEP) in Ebonyi and Imo States, South-East, Nigeria. The specific objectives were to describe the socioeconomic characteristics of agricultural extension personnel in Ebonyi and Imo States, and to ascertain the digital literacy level of AEP in the studied states. Purposive sampling technique was used to select 312 Agricultural Extension personnel (132 from Ebonyi State Agricultural Development Program and 180 from Imo State Agricultural Development Program) for the study. Data were collected through the use of validated and structured questionnaire, and administered through the help of well-trained enumerators. Data were analysed using simple descriptive statistical tools such as percentages mean score, standard deviation and weighted mean. Findings indicated that they were more male in the both States (55.3% and 57.8%) for Ebonyi and Imo State respectively and that the average age of AEP in Ebonyi and Imo States were 44.7 years and 49.2 years respectively. It was further revealed that the majority (77.3% and 82.8%) had B.Sc./HND as their highest academic qualifications, belonged to professional organisations (62.1% and 75%), and were earning an average monthly income of N58,798 and N62,648 for Ebonyi and Imo State respectively. Also, it was revealed that their mean years of service were 12.4 years and 13.4 years for Ebonyi and Imo State respectively. Almost all of them (87.9% and 95.0%) own a smartphone, had access to the internet (80.3% and 90.0%), but do not own a laptop/ipad (82.6% and 72.8%) for Ebon-yi and Imo State respectively. Results further revealed that Agricultural extension personnel in both Ebonyi and Imo State respectively had low digital literacy level ( = 2.41 and 2.32). The study concluded that AEP in Ebonyi and Imo State respectively had similar socioeconomic characteristics and low level of digital literacy. The study recommended that the management of ADPs in both Ebonyi and Imo State should ensure the training of AEP in digital skills to enhance their digital literacy level to enable them use digital technologies in their work. 展开更多
关键词 Agricultural Extension Personnel Digital Literacy Ebonyi state Imo state Socioeconomic characteristics
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Empowering the Future: Exploring the Construction and Characteristics of Lithium-Ion Batteries
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作者 Dan Tshiswaka Dan 《Advances in Chemical Engineering and Science》 CAS 2024年第2期84-111,共28页
Lithium element has attracted remarkable attraction for energy storage devices, over the past 30 years. Lithium is a light element and exhibits the low atomic number 3, just after hydrogen and helium in the periodic t... Lithium element has attracted remarkable attraction for energy storage devices, over the past 30 years. Lithium is a light element and exhibits the low atomic number 3, just after hydrogen and helium in the periodic table. The lithium atom has a strong tendency to release one electron and constitute a positive charge, as Li<sup> </sup>. Initially, lithium metal was employed as a negative electrode, which released electrons. However, it was observed that its structure changed after the repetition of charge-discharge cycles. To remedy this, the cathode mainly consisted of layer metal oxide and olive, e.g., cobalt oxide, LiFePO<sub>4</sub>, etc., along with some contents of lithium, while the anode was assembled by graphite and silicon, etc. Moreover, the electrolyte was prepared using the lithium salt in a suitable solvent to attain a greater concentration of lithium ions. Owing to the lithium ions’ role, the battery’s name was mentioned as a lithium-ion battery. Herein, the presented work describes the working and operational mechanism of the lithium-ion battery. Further, the lithium-ion batteries’ general view and future prospects have also been elaborated. 展开更多
关键词 Lithium-Ion Batteries Battery Construction Battery characteristics Energy Storage Electrochemical Cells Anode Materials Cathode Materials state of Charge (SOC) Depth of Discharge (DOD) Solid Electrolyte Interface (SEI)
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Configuration Selection for Reconfigurable Manufacturing Systems by Means of Characteristic State Space 被引量:2
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作者 HUANG Liang GAO Yuan +2 位作者 QIAN Feng TANG Suzhou WANG Delun 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第1期23-32,共10页
The configuration selection for reconfigurable manufacturing systems(RMS) have been tackled in a number of studies by using analytical or simulation models. The simulation models are usually based on fewer assumptio... The configuration selection for reconfigurable manufacturing systems(RMS) have been tackled in a number of studies by using analytical or simulation models. The simulation models are usually based on fewer assumptions than the analytical models and therefore are more wildly used in modeling complex RMS. But in the absence of an efficient gradient analysis method of the objective function, it is time-consuming in solving large-scale problems by using a simulation model coupled with a meta-heuristics algorithm. In this paper, a new approach by means of characteristic state space is presented to improve the efficiency of the configuration selection for an RMS. First, a characteristic state equation is set up to represent the input and the output resources of each basic activity in an RMS. A production process model in terms of matrix equations is established by iterating the equations of basic activities according to the resource flows. This model introduces the production process into a characteristic state space for further analysis. Second, the properties of the characteristic state space are presented. On the basis of these properties, the configuration selection in an RMS is considered as a path-planning problem, and the gradient of the objective function is computed. Modified simulated annealing(SA) is also presented, in which neighborhood generation is guided by the gradient to accelerate convergence and reduce the run time of the optimization procedure. Finally, several case studies on the configuration selection for some actual reconfigurable assembly job-shops are presented and compared to the classical SA. The comparison shows relatively positive results. This study provides a more efficient configuration selection approach by using the gradient of the objective function and presents the relevant theories on which it is based. 展开更多
关键词 reconfigurable manufacturing system configuration selection characteristic state space simulated annealing
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Relations Between Characteristic Function,Positive P-Representation and Coherent Thermal State 被引量:1
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作者 FAN Hong-Yi XU Xing-Lei Department of Material Science and Engineering,University of Science and Technology of China,Hefei 230026,China2 Department of Physics,Shanghai Jiao Tong University,Shanghai 200030,China3 Department of Physics,Heze University,Heze 274015,China 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第7期67-70,共4页
We employ the coherent thermal states(a kind of entangled states)in thermal field dynamics to establisha complete entangled state formalism expressing pseudo-classical representations of density operator for light fie... We employ the coherent thermal states(a kind of entangled states)in thermal field dynamics to establisha complete entangled state formalism expressing pseudo-classical representations of density operator for light field.Especially,the relationship between the coherent thermal state and the characteristic function and the positive Prepresentation in quantum optics theory are obtained. 展开更多
关键词 coherent thermal state characteristic function positive P-representation
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Statistical Properties and Algebraic Characteristics of Quantum Superpositions of Negative Binomial States 被引量:1
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作者 WANGXiao-Guang FUHong-Chen 《Communications in Theoretical Physics》 SCIE CAS CSCD 2001年第6期729-734,共6页
We introduce new kinds of states of quantized radiation fields, which are the superpositions of negative binomial states. They exhibit remarkable nonclassical properties and reduce to Schrodinger cat states in a certa... We introduce new kinds of states of quantized radiation fields, which are the superpositions of negative binomial states. They exhibit remarkable nonclassical properties and reduce to Schrodinger cat states in a certain limit.The algebras involved in the even and odd negative binomial states turn out to be generally deformed oscillator algebras.It is found that the even and odd negative binomial states satisfy the same eigenvalue equation with the same eigenvalue and they can be viewed as two-photon nonlinear coherent states. Two methods of generating such the states are proposed. 展开更多
关键词 量子力学 负二项态 量子叠加 代数特征 统计特征
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EFFECT OF THE EXISTING STATES OF CHROMIUM ION ON THE COLOR CHARACTERISTICS OF DOPED β-C_2S
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作者 冯修吉 阎培玉 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1990年第2期1-8,共8页
According to the theory of crystal field, the existing state of chromium ions in β-C_2S was studied with optical spectra and EPR. The energy levels of chromium ions were calculated. Chromium ions exist in form of Cr^... According to the theory of crystal field, the existing state of chromium ions in β-C_2S was studied with optical spectra and EPR. The energy levels of chromium ions were calculated. Chromium ions exist in form of Cr^(4+) and Cr^(5+) coordinated with distorted octahedra. The reason of fading of β-C_2S hydrate is that the strength of light absorption declines be- cause of the valence change of chromium ions and chroninm dissolves out and loses in water. 展开更多
关键词 Doped 6-C_2S Color characteristics Existing state Chromium ion
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CHARACTERISTICS OF CRITICAL STATE OF TENSILE INSTABILITY
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作者 Zhou Weixian(Department of Aeronautical Manufacturing Engineering, Northwestern Polytechnical University, Xi’an 710072) 《中国有色金属学会会刊:英文版》 CSCD 1996年第3期58-62,共5页
CHARACTERISTICSOFCRITICALSTATEOFTENSILEINSTABILITY¥ZhouWeixian(DepartmentofAeronauticalManufacturingEngineer... CHARACTERISTICSOFCRITICALSTATEOFTENSILEINSTABILITY¥ZhouWeixian(DepartmentofAeronauticalManufacturingEngineering,NorthwesternP... 展开更多
关键词 TENSILE INSTABILITY CRITICAL state DEFORMATION characteristic
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A study on the distribution characteristics and existing states of cadmium in the Jinding Pb-Zn deposit,Yunnan Province,China 被引量:2
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作者 YE Lin CHENG Zengtao +2 位作者 PAN Ziping LIU Tiegeng GAO Wei 《Chinese Journal Of Geochemistry》 EI CAS 2010年第3期319-325,共7页
The distribution characteristics and existing state of cadmium in the Jinding Pb-Zn deposit were studied. It was discovered that Cd was mainly distributed in sphalerite as an isomorphic impurity. There was a good corr... The distribution characteristics and existing state of cadmium in the Jinding Pb-Zn deposit were studied. It was discovered that Cd was mainly distributed in sphalerite as an isomorphic impurity. There was a good correlation between Cd and Zn in the primary ore. With the oxidation and resolution of pyrite, sphalerite, sulfide, and etc., many secondary minerals, such as colloform sphalerite and smithsonite, were formed. The distribution of Cd is not symmetrical, and enrichment and dilution were observed in partial area of the oxidation zone in the deposit. Cd, except in external pore space or cracks of secondary minerals as independent minerals, such as greenockite, was mainly distributed in sphalerite as an isomorphic impurity in the secondary sphalerate and smithsonite in the oxidation zone. The research showed that Cd showed a very strong active transfer ability in the oxidation process, not only indicating that supergene leaching might be the main reason for Cd enrichment in some Pb-Zn deposits, but also reflecting that Cd was easily mobilizeed and transferred to pollute ore areas in the oxidation process. Furthermore, Cd in oxidation ore was more easily mobilized and transferred to induce bad hazards for ore areas with the effect from AMD which was produced from oxidation of sulfides. 展开更多
关键词 金顶铅锌矿 氧化镉 特征 作者 云南 中国 次生矿物 氧化过程
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Characteristics of anxiety among primary and middle school teachers: a Content-based approach to state anxiety
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作者 Lijuan Wang Dajun Zhang 《Health》 2012年第1期26-31,共6页
Anxiety has become one of the major psychological problems which harass people in modern times;this problem is particularly obvious with primary and middle school teachers. Based on the contents of anxiety, the self-c... Anxiety has become one of the major psychological problems which harass people in modern times;this problem is particularly obvious with primary and middle school teachers. Based on the contents of anxiety, the self-compiled Teachers’ State Anxiety Questionnaire (TSAQ) was used to investigate the effective of 1930 subjects in seven regions of China through stratified random sampling methodology. The results show that that the sense of anxiety for satisfaction and control is higher in male teachers;and the sense of teachers’ anxiety for satisfaction and conflict is severe in the key middle school;and the sense of conflict anxiety in the married teachers is the highest;the anxiety in all are high in teachers with poor physical health and main teacher as well as the teachers with poor economic situation in their family. The feasibility of measures to improve the teachers’ state anxiety in primary and middle school should be considered to enhance the level of teachers’ mental health, work efficiency and quality of life. 展开更多
关键词 PRIMARY and SECONDARY TEACHERS state ANXIETY characteristicS
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Real-time road traffic states estimation based on kernel-KNN matching of road traffic spatial characteristics 被引量:2
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作者 徐东伟 王永东 +2 位作者 贾利民 张贵军 郭海锋 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第9期2453-2464,共12页
The accurate estimation of road traffic states can provide decision making for travelers and traffic managers. In this work,an algorithm based on kernel-k nearest neighbor(KNN) matching of road traffic spatial charact... The accurate estimation of road traffic states can provide decision making for travelers and traffic managers. In this work,an algorithm based on kernel-k nearest neighbor(KNN) matching of road traffic spatial characteristics is presented to estimate road traffic states. Firstly, the representative road traffic state data were extracted to establish the reference sequences of road traffic running characteristics(RSRTRC). Secondly, the spatial road traffic state data sequence was selected and the kernel function was constructed, with which the spatial road traffic data sequence could be mapped into a high dimensional feature space. Thirdly, the referenced and current spatial road traffic data sequences were extracted and the Euclidean distances in the feature space between them were obtained. Finally, the road traffic states were estimated from weighted averages of the selected k road traffic states, which corresponded to the nearest Euclidean distances. Several typical links in Beijing were adopted for case studies. The final results of the experiments show that the accuracy of this algorithm for estimating speed and volume is 95.27% and 91.32% respectively, which prove that this road traffic states estimation approach based on kernel-KNN matching of road traffic spatial characteristics is feasible and can achieve a high accuracy. 展开更多
关键词 状态估计方法 道路交通 交通空间 特性匹配 高维特征空间 交通状态 实时 数据序列
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Coupling effects of hydrological characteristics and nutrient load in sediments on the trophic state of reservoirs
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作者 Fan Xinyi Yue Yihong +5 位作者 Mei Lin Li Xiaoying Hu Zhehui Luo Jiajie Liu Liu Wang Fushun 《Acta Geochimica》 EI CAS CSCD 2021年第4期640-649,共10页
Currently,lakes and artificial reservoirs are increasingly threatened by eutrophication,which is the result of the combined action of many natural and anthropogenic factors.In the past,the effect of nutrient load on t... Currently,lakes and artificial reservoirs are increasingly threatened by eutrophication,which is the result of the combined action of many natural and anthropogenic factors.In the past,the effect of nutrient load on the trophic state of water bodies has attracted much attention,while few studies have addressed the effect of hydrological characteristics.Therefore,to reveal the coupling effects of hydrological characteristics and nutrient load in sediments on the trophic state of water bodies,this study collected relevant data from 36 lakes and reservoirs across China.Pearson correlation analysis showed that trophic level index was positively and significantly correlated with nutrient load in sediments and hydraulic retention time,while it was negatively correlated with mean depth and hydraulic load.The principal component analysis showed that the nutrient load was the first major component that influenced the trophic state of water bodies,followed by the mean depth and hydraulic retention time.Eutrophication was prone to occur in water bodies with mean depth less than 7 m and hydraulic retention time greater than 14 d,and the trophic level index regression equation with hydrological characteristics and nutrient load in sediments was derived by multiple regression analysis.This study revealed that the trophic state of water bodies influenced by both nutrient load and hydrological characteristics.It provides a new idea to reduce the occurrence of eutrophication in reservoirs by using the artificial hydrological regulation capacity of reservoirs. 展开更多
关键词 Artificial reservoirs Hydrological characteristics Nutrient load Trophic state of water bodies
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Effects of Wind on Steady-state Scan Characteristics and Hit Probability of Terminal-sensitive Projectile 被引量:4
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作者 郭锐 刘荣忠 +1 位作者 王宇波 黄风华 《Defence Technology(防务技术)》 SCIE EI CAS 2010年第1期16-19,共4页
The wind effects on steady-state scan characteristics and hit probability of terminal-sensitive projectile were discussed in this paper. Considering wind as the constitutions of the average wind and the impulsive wind... The wind effects on steady-state scan characteristics and hit probability of terminal-sensitive projectile were discussed in this paper. Considering wind as the constitutions of the average wind and the impulsive wind, a simplified wind field model was established for the ballistic calculation of the steady-state scan phase; under the windy condition, the effects of the range wind and the beam wind on the steady-state scan characteristics of the terminal-sensitive projectile were analyzed in detail and its hit probabilities for a certain armored target were calculated. The calculated results show that, when the wind speed exceeds a certain value, the hit probabilities of terminal-sensitive projectile drop rapidly; the wind effects must be considered in the application of the terminal-sensitive projectiles. This paper provides some theoretical references for the fire wind speed correction and the global structure optimization of the terminal-sensitive projectile. 展开更多
关键词 launch and flight technology of aerocraft terminal-sensitive projectile steady-state scan characteristics wind speed correction hit probability
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Preparation and electrochemical characteristics of Co_3(PO_4)_2-coated LiNi_(0.8)Co_(0.2)O_2 by solid-state reaction at room temperature
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作者 DENG Xinrong HU Guorong PENG Zhongdong YANG Yanan CAO Yanbing DU Ke 《Rare Metals》 SCIE EI CAS CSCD 2008年第5期502-506,共5页
LiNi0.8Co0.2O2 particles were modified by Co3(PO4)2 coating. The effects of the Co3(PO4)2 coating on the structure and electrochemical properties of the LiNi0.8Co0.2O2 cathode material were investigated. The Co3... LiNi0.8Co0.2O2 particles were modified by Co3(PO4)2 coating. The effects of the Co3(PO4)2 coating on the structure and electrochemical properties of the LiNi0.8Co0.2O2 cathode material were investigated. The Co3(PO4)2 coating forms a thin layer on the surface of the LiNi0.8Co0.2O2 material and a solid solution by interacting with the LiNi0.8Co0.2O2 core material during calcination at 700℃ for 4 h. Charge-discharge experiment results show that the Co3(PO4)2 coating improves the cycling stability of the LiNi0.8Co0.2O2 cathode material. The capacity retention of the pristine LiNi0.8Co0.2O2 cathode after 50 cycles is 83.6%, whereas it is 91.7% in the case of the LiNi0.8Co0.2O2 cathode coated with 1 wt.% Co3(PO4)2. Storage tests of the 4.35 V charged electrode at 60℃ after a month show that the Co3(POg)2-coated sample exhibits good storage properties compared with the pristine sample. 展开更多
关键词 lithium ion battery coating solid-state reaction Co3(PO4)2 electrochemical characteristics
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The occurrences and geochemical characteristics of thorium in iron ore in the Bayan Obo deposit, Northern China 被引量:1
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作者 Xiaozhi Hou Zhanfeng Yang +1 位作者 Zhenjiang Wang Wencai Wang 《Acta Geochimica》 EI CAS CSCD 2020年第1期139-154,共16页
The Bayan Obo deposit in northern China is an ultra-large Fe–REE–Nb deposit.The occurrences,and geochemical characteristics of thorium in iron ores from the Bayan Obo Main Ore Body were examined using chemical analy... The Bayan Obo deposit in northern China is an ultra-large Fe–REE–Nb deposit.The occurrences,and geochemical characteristics of thorium in iron ores from the Bayan Obo Main Ore Body were examined using chemical analysis,field emission scanning electron microscopy,energy dispersive spectrometer,and automatic mineral analysis software.Results identified that 91.69%of ThO2 in the combined samples was mainly distributed in rare earth minerals(bastnaesite,huanghoite,monazite;56.43%abundance in the samples),iron minerals(magnetite,hematite,pyrite;20.97%),niobium minerals(aeschynite;14.29%),and gangue minerals(aegirine,riebeckite,mica,dolomite,apatite,fluorite;4.22%).An unidentified portion(4.09%)of ThO2 may occur in other niobium minerals(niobite,ilmenorutile,pyrochlore).Only a few independent minerals of thorium occur in the iron ore samples.Thorium mainly occurs in rare earth minerals in the form of isomorphic substitution.Analyses of the geochemical characteristics of the major elements indicate that thorium mineralization in the Main Ore Body was related to alkali metasomatism,which provided source material and favorable porosity for hydrothermal mineralization.Trace elements such as Sc,Nb,Zr,and Ta have higher correlation coefficients with thorium,which resulted from being related to the relevant minerals formed during thorium mineralization.In addition,correlation analysis of ThO2 and TFe,and REO and TFe in the six types of iron ore samples showed that ThO2 did not always account for the highest distribution rate in rare earth minerals,and the main occurrence minerals of ThO2 were closely related to iron ore types. 展开更多
关键词 THORIUM Occurrence state Distribution law Geochemical characteristics Iron ore Bayan Obo deposit
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Adhesive Bonding and Self-Curing Characteristics of α-Starch Based Composite Binder for Green Sand Mould/Core 被引量:1
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作者 XiaZHOU JinzongYANG GuohuiQU 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2004年第5期617-621,共5页
Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and the... Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and theories of the binder at room temperature were proposed according to the interactions between various compositions. Thus, the reasons for the binder to have excellent combination properties and unique adhesive bonding and self-curing characteristics were explained by these theories successfully. And the theories are of great directive importance to design and development of composite binder for green sand mould/core. 展开更多
关键词 α-Starch based composite binder Interaction Adhesive bonding Self-curing characteristic Green state
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Transient Characteristics of a High-Capacity Centrifugal Pump during Rapidly Regulating Discharge Valve 被引量:1
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作者 季英瑜 张玉良 《Journal of Donghua University(English Edition)》 EI CAS 2017年第1期60-65,共6页
In order to reveal the instantaneous characteristics of a high-capacity centrifugal pump during rapidly regulating discharge valve,theoretical analysis and numerical simulation are employed.The transient characteristi... In order to reveal the instantaneous characteristics of a high-capacity centrifugal pump during rapidly regulating discharge valve,theoretical analysis and numerical simulation are employed.The transient characteristics of the pump model under off-design condition were theoretically analyzed based on the generalized basic equation of vane pumps.The study showed that a centrifugal pump with radial straight blades at off-design condition almost had no transient effect,whereas a centrifugal pump with common backward-curved blades had transient effects that were directly related to the regularity of adjusting flowrate.Calculation examples show that transient effects are insignificant.The finite volume method and re-normalization group(RNG)κ-ε turbulence model were adopted to accomplish a 3D numerical calculation of a mediumspecific-speed centrifugal pump under the off-design condition.The transient process at the off-design condition is mainly caused by the time-varying intrinsic pulsation from the stator-rotor interference and by the time-varying consequent pulsation from the changes in flow rate. 展开更多
关键词 centrifugal pump off-design condition transient effect theoretical analysis stator-rotor interaction pulsation characteristics
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Study on Operating Characteristics of Power Plant with Dry and Wet Cooling Systems 被引量:1
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作者 Tao Tang Jian-qun Xu +1 位作者 Sheng-xiang Jin Hong-qi Wei 《Energy and Power Engineering》 2013年第4期651-656,共6页
The represent paper will study the performance of the power plant with the combination of dry and wet cooling systems in different operating conditions. A thermodynamic performance analysis of the steam cycle system w... The represent paper will study the performance of the power plant with the combination of dry and wet cooling systems in different operating conditions. A thermodynamic performance analysis of the steam cycle system was performed by means of a program code dedicated to power plant modeling in design operating condition. Then the off-design behavior was studied by varying not only the ambient temperature and relative humidity but also several parameters connected to the cooling performance, like the exhaust steam flow rate, the air cooling fan load and the number of operating cooling water pumps and cooling towers. The result is an optimum set of variables allowing the dry and wet cooling system be regulated in such a way that the maximum power is achieved and low water consumption. 展开更多
关键词 DRY and WET CONDENSER Cooling TOWER off-design characteristic CURVE Operational Optimization
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Time-series analysis of the characteristic pressure fluctuations in a conical fluidized bed with negative pressure 被引量:1
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作者 Sheng Fang Yanding Wei +2 位作者 Lei Fu Geng Tian Haibin Qu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第4期87-99,共13页
The negative pressure conical fluidized bed is widely used in the pharmaceutical industry.In this study,experiments based on the negative pressure conical fluidized bed are carried out by changing the material mass an... The negative pressure conical fluidized bed is widely used in the pharmaceutical industry.In this study,experiments based on the negative pressure conical fluidized bed are carried out by changing the material mass and particle size.The pressure fluctuation signals are analyzed by the time and the frequency domain methods.A method for absolutely characterizing the degree of the energy concentration at the main frequency is proposed,where the calculation is to divide the original power spectrum by the average signal power.A phenomenon where the gas velocity curve temporarily stops growing is observed when the material mass is light,and the particle size is small.The standard deviation and kurtosis both rapidly change at the minimum fluidization velocity and thus can be used to determine the flow regime,and the variation rule of the kurtosis is independent of both the material mass and particle size.In the initial fluidization stage,the dominant pressure signal comes from the material movement;with the increase in the gas velocity,the power of a 2.5 Hz signal continues to increase.A method of dividing the main frequency by the average cycle frequency can conveniently determine the fluidized state,and a novel concept called stable fluidized zone proposed in this paper can be obtained.Controlling the gas velocity within the stable fluidized zone ensures that the fluidized bed consistently remains in a stable fluidized state. 展开更多
关键词 Conical fluidized bed Negative pressure Pressure fluctuation Time-series analysis characteristic value Fluidized state
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Experimental study on the oil production characteristics during the waterflooding of different types of reservoirs in Ordos Basin, NW China 被引量:1
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作者 XIAO Wenlian YANG Yubin +7 位作者 LI Min LI Nong YOU Jingxi ZHAO Jinzhou ZHENG Lingli ZHOU Kerning REN Jitian WANG Yue 《Petroleum Exploration and Development》 CSCD 2021年第4期935-945,共11页
Waterflooding experiments were conducted in micro-models(microscopic scale)and on plunger cores from low permeability,extra-low permeability and ultra-low permeability reservoirs in the Ordos Basin under different dis... Waterflooding experiments were conducted in micro-models(microscopic scale)and on plunger cores from low permeability,extra-low permeability and ultra-low permeability reservoirs in the Ordos Basin under different displacement pressures using the NMR techniques to find out pore-scale oil occurrence state,oil production characteristics and residual oil distribution during the process of waterflooding and analyze the effect of pore structure and displacement pressure on waterflooding efficiency.Under bound water condition,crude oil mainly occurs in medium and large pores in the low-permeability sample,while small pores and medium pores are the main distribution space of crude oil in extra-low permeability and ultra-low permeability samples.During the waterflooding,crude oil in the medium and large pores of the three types of samples are preferentially produced.With the decrease of permeability of the samples,the waterflooding front sequentially shows uniform displacement,network displacement and finger displacement,and correspondingly the oil recovery factors decrease successively.After waterflooding,the residual oil in low-permeability samples is mainly distributed in medium pores,and appears in membranous and angular dispersed phase;but that in the extra-low and ultra-low permeability samples is mainly distributed in small pores,and appears in continuous phase formed by a bypass flow and dispersed phase.The low-permeability samples have higher and stable oil displacement efficiency,while the oil displacement efficiency of the extra-low permeability and ultra-low permeability samples is lower,but increases to a certain extent with the increase of displacement pressure. 展开更多
关键词 waterflooding characteristics oil occurrence state residual oil distribution NMR displacement efficiency Ordos Basin
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Characteristic signal extracted from a continuous time signal on the aspect of frequency domain
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作者 杜志凡 张瑞浩 陈红 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第9期124-130,共7页
Extracting characteristic signal from a continuous signal can effectively reduce the difficulty of analyzing the running states of a single-variable nonlinear system.Whether the extracted characteristic signal can acc... Extracting characteristic signal from a continuous signal can effectively reduce the difficulty of analyzing the running states of a single-variable nonlinear system.Whether the extracted characteristic signal can accurately reflect the running states of the system is very important.In this paper, a method called automatic sampling method(ASM) for extracting characteristic signals is investigated.The complete definition is described, the effectiveness is proved theoretically, and the general formulas of the extracted characteristic signals are derived for the first time.Furthermore, typical Chua's circuit is used to accomplish a lot of experimental research on the aspect of frequency domain.The experimental results show that ASM is feasible and practical, and can automatically generate a characteristic signal with the change of the original signal. 展开更多
关键词 automatic sampling method characteristic SIGNAL frequency DOMAIN system stateS
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