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Differential Equation Model of Carbon, Nitrogen and Zinc Components in Growing Tomatoes
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作者 Weijie Lin Hailing Xian +3 位作者 Wenwen Wang Caiyun Huang Zhenkun Jiang Xiaoliang Zhou 《Open Journal of Modelling and Simulation》 2022年第3期303-313,共11页
Tomato is a common food on the human table. Up to now, the research on the growth and development model of tomato has been about 50 years. There are many researches on the main nutrients of tomato, such as carbon and ... Tomato is a common food on the human table. Up to now, the research on the growth and development model of tomato has been about 50 years. There are many researches on the main nutrients of tomato, such as carbon and nitrogen, but few on the trace element zinc. In this paper, taking plant nutrient C, N and Z<sub>n</sub> as variables, the differential equation model of C, N and Z<sub>n</sub> in tomato growth and development was established. According to the research of tomato as a whole and divided into root and leaf, the one-compartment and two-compartment models of tomato growth and development were established. The model was analyzed by Matlab program, and the existing experimental data was used to test the numerical simulation results, which proves that the model conforms to the facts. 展开更多
关键词 Carbon Nitrogen and Zinc differential Equation model Tomato Growth and Development
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Novel Computing for the Delay Differential Two-Prey and One-Predator System
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作者 Prem Junsawang Zulqurnain Sabir +3 位作者 Muhammad Asif Zahoor Raja Soheil Salahshour Thongchai Botmart Wajaree Weera 《Computers, Materials & Continua》 SCIE EI 2022年第10期249-263,共15页
The aim of these investigations is to find the numerical performances of the delay differential two-prey and one-predator system.The delay differential models are very significant and always difficult to solve the dyn... The aim of these investigations is to find the numerical performances of the delay differential two-prey and one-predator system.The delay differential models are very significant and always difficult to solve the dynamical kind of ecological nonlinear two-prey and one-predator system.Therefore,a stochastic numerical paradigm based artificial neural network(ANN)along with the Levenberg-Marquardt backpropagation(L-MB)neural networks(NNs),i.e.,L-MBNNs is proposed to solve the dynamical twoprey and one-predator model.Three different cases based on the dynamical two-prey and one-predator system have been discussed to check the correctness of the L-MBNNs.The statistic measures of these outcomes of the dynamical two-prey and one-predator model are chosen as 13%for testing,12%for authorization and 75%for training.The exactness of the proposed results of L-MBNNs approach for solving the dynamical two-prey and onepredator model is observed with the comparison of the Runge-Kutta method with absolute error ranges between 10−05 to 10−07.To check the validation,constancy,validity,exactness,competence of the L-MBNNs,the obtained state transitions(STs),regression actions,correlation presentations,MSE and error histograms(EHs)are also provided. 展开更多
关键词 Delay differential model dynamical system PREY-PREDATOR Levenberg-Marquardt backpropagation MSE neural networks
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Medical X-Ray Image Enhancement Based on Kramer's PDE Model
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作者 Yan-Fei Zhao Qing-Wei Gao +1 位作者 De-Xiang Zhang Yi-Xiang Lu 《Journal of Electronic Science and Technology of China》 2007年第2期187-190,共4页
The purpose of this study is to present an application of a novel enhancement technique for enhancing medical images generated from X-rays. The method presented in this study is based on a nonlinear partial differenti... The purpose of this study is to present an application of a novel enhancement technique for enhancing medical images generated from X-rays. The method presented in this study is based on a nonlinear partial differential equation (PDE) model, Kramer's PDE model. The usefulness of this method is investigated by experimental results. We apply this method to a medical X-ray image. For comparison, the X-ray image is also processed using classic Perona-Malik PDE model and Catte PDE model. Although the Perona-Malik model and Catte PDE model could also enhance the image, the quality of the enhanced images is considerably inferior compared with the enhanced image using Kramer's PDE model. The study suggests that the Kramer's PDE model is capable of enhancing medical X-ray images, which will make the X-ray images more reliable. 展开更多
关键词 Terms-Enhancement nonlinear partial differential equation (PDE) partial differential equation model X-ray image.
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Shear-horizontal waves in periodic layered nanostructure with both nonlocal and interface effects
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作者 Ru TIAN Jinxi LIU +1 位作者 E.N.PAN Yuesheng WANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2020年第10期1447-1460,共14页
The propagation of shear-horizontal(SH)waves in the periodic layered nanocomposite is investigated by using both the nonlocal integral model and the nonlocal differential model with the interface effect.Based on the t... The propagation of shear-horizontal(SH)waves in the periodic layered nanocomposite is investigated by using both the nonlocal integral model and the nonlocal differential model with the interface effect.Based on the transfer matrix method and the Bloch theory,the band structures for SH waves with both vertical and oblique incidences to the structure are obtained.It is found that by choosing appropriate interface parameters,the dispersion curves predicted by the nonlocal differential model with the interface effect can be tuned to be the same as those based on the nonlocal integral model.Thus,by propagating the SH waves vertically and obliquely to the periodic layered nanostructure,we could invert,respectively,the interface mass density and the interface shear modulus,by matching the dispersion curves.Examples are further shown on how to determine the interface mass density and the interface shear modulus in theory. 展开更多
关键词 shear-horizontal(SH)wave nonlocal theory interface effect NANOSTRUCTURE integral model differential model
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Modeling, simulation, and prediction of global energy indices: a differential approach
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作者 Stephen Ndubuisi NNAMCHI Onyinyechi Adanma NNAMCHI +2 位作者 Janice Desire BUSINGYE Maxwell Azubuike IJOMAH Philip Ikechi OBASI 《Frontiers in Energy》 SCIE CSCD 2022年第2期375-392,共18页
Modeling, simulation, and prediction of global energy indices remain veritable tools for econometric, engineering, analysis, and prediction of energy indices. Thus, this paper differentially modeled, simulated, and no... Modeling, simulation, and prediction of global energy indices remain veritable tools for econometric, engineering, analysis, and prediction of energy indices. Thus, this paper differentially modeled, simulated, and non-differentially predicated the global energy indices. The state-of-the-art of the research includes normalization of energy indices, generation of differential rate terms, and regression of rate terms against energy indices to generate coefficients and unexplained terms. On imposition of initial conditions, the solution to the system of linear differential equations was realized in a Matlab environment. There was a strong agreement between the simulated and the field data. The exact solutions are ideal for interpolative prediction of historic data. Furthermore, the simulated data were upgraded for extrapolative prediction of energy indices by introducing an innovative model, which is the synergy of deflated and inflated prediction factors. The innovative model yielded a trendy prediction data for energy consumption, gross domestic product, carbon dioxide emission and human development index. However, the oil price was untrendy, which could be attributed to odd circumstances. Moreover, the sensitivity of the differential rate terms was instrumental in discovering the overwhelming effect of independent indices on the dependent index. Clearly, this paper has accomplished interpolative and extrapolative prediction of energy indices and equally recommends for further investigation of the untrendy nature of oil price. 展开更多
关键词 energy indices differential model NORMALIZATION SIMULATION INFLATION DEFLATION predictive factor and prediction rate
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Multitemporal UAV-based photogrammetry for landslide detection and monitoring in a large area:a case study in the Heifangtai terrace in the Loess Plateau of China 被引量:5
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作者 XU Qiang LI Wei-le +2 位作者 JU Yuan-zhen DONG Xiu-jun PENG Da-lei 《Journal of Mountain Science》 SCIE CSCD 2020年第8期1826-1839,共14页
With high spatial resolution,on-demand-flying ability,and the capacity for obtaining threedimensional measurements,unmanned aerial vehicle(UAV)photogrammetry is widely used for detailed investigations of single landsl... With high spatial resolution,on-demand-flying ability,and the capacity for obtaining threedimensional measurements,unmanned aerial vehicle(UAV)photogrammetry is widely used for detailed investigations of single landslides,but its effectiveness for landslide detection and monitoring in a large area needs to be investigated.The Heifangtai terrace in the Loess Plateau of China is a loess terrace that is extremely susceptible to irrigation-induced loess landslides.This paper used UAV-based photogrammetry for a series of highresolution images spanning over 30 months for landslide detection and monitoring of the terrace with an area of 32 km^2.Dense and evenly distributed ground control points were established and measured to ensure the high accuracy of the photogrammetry results.The structure-from-motion(Sf M)technique was used to convert overlapping images into orthographic images,3D point clouds,digital surface models(DSMs)and mesh models.Using multitemporal differential mesh models,landslide vertical movements and potential landslides were detected and monitored.The results indicate that a combination of UAV-based orthophotos and differential mesh models can be used for flexible and accurate detection and monitoring of potential loess landslides in a large area. 展开更多
关键词 Unmanned Aerial Vehicle Loess Plateau Landslide detection Landslide monitoring differential mesh model Vertical movement
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Research on China’s Population Structure in the New Situation
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作者 Jingxuan Cui Mengshuai Yin Zerong Liu 《Macro Management & Public Policies》 2020年第2期12-17,共6页
To analyze the impact of the“two-child policy”on the population size and structure,first of all,the birth rate,the ratio of men and women,and the ratio of urban and rural population are used as indicators.Before and... To analyze the impact of the“two-child policy”on the population size and structure,first of all,the birth rate,the ratio of men and women,and the ratio of urban and rural population are used as indicators.Before and after the dispersion,then establish a PDE model,and compare it with the population predicted by the gray forecast to analyze the mitigation of the ageing of the second child policy;continue to analyze the impact of changes in the population structure on the national economy,and select the male and female ratio and the labor population The urban-rural population ratio is used as an index to establish a multiple regression equation for analysis,and a related regression equation is obtained.Finally,the future marriage problem is analyzed,considering only the difference in the number of men and women entering the marriageable period at the same time.The difference in the number of marriageable populations is analyzed through the difference in the number of men and women born at birth,focusing on a dynamic perspective. 展开更多
关键词 Variance analysis PDE model differential equation model Multiple regression model Second child policy
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The J_2 invariant relative configuration of spaceborne SAR interferometer for digital elevation measurement
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作者 Ming Xu Ying-Hong Jia Shi-Jie Xu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第4期643-651,共9页
A 3-craft formation configuration is proposed to perform the digital elevation model (DEM) for the distributed spacebome interferometric synthetic aperture radar (InSAR), and it is optimized by the modified ant co... A 3-craft formation configuration is proposed to perform the digital elevation model (DEM) for the distributed spacebome interferometric synthetic aperture radar (InSAR), and it is optimized by the modified ant colony algorithm to have the best compatibility with J2 invariant orbits created by differential correction algorithm. The configuration has succeeded in assigning the across-track baseline to vary periodically and with its mean value equal to the optimal baseline determined by the relative height measurement accuracy. The required relationship between crafts' magnitudes and phases is formulated for the general case of interferometry measure from non-orthographic and non-lateral view. The J2 invariant configurations created by differential correction algorithm are employed to investigate their compatibility with the required configuration. The colony algorithm is applied to search the optimal configuration holding the near-constant across-track baseline under the J2 perturbation, and the absolute height measurement accuracy is preferable as expected. 展开更多
关键词 InSAR Digital elevation model (DEM) J2 invariant orbit differential correction algorithm Formation flying
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A 3-D Differential Method for Solving Rolling Force of PC Hot Strip Mill 被引量:3
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作者 WANG Xue-song PENG Yan XU Li-pu LIU Hong-min 《Journal of Iron and Steel Research(International)》 SCIE EI CAS CSCD 2010年第9期36-39,共4页
The character of the deformation zone on pair cross rolls is different from that of the regular 4-high mill. Considering comprehensive influences of normal stress and shear stress in rolling direction, width direction... The character of the deformation zone on pair cross rolls is different from that of the regular 4-high mill. Considering comprehensive influences of normal stress and shear stress in rolling direction, width direction and thickness direction, the rolling force calculation model of the PC (pair crossed) hot strip mill is built. Taking the entry stress and the exit stress of strip as the boundary conditions, the longitudinal and transverse distribution of rolling force is worked out by the differential method. Then the total rolling force is calculated, and calculated results are verified by experimental data. 展开更多
关键词 PC rolling mill rolling force differential method model building
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Dynamical Behavior of SEIR-SVS Epidemic Models with Nonlinear Incidence and Vaccination 被引量:1
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作者 Xiao-mei FENG Li-li LIU Feng-qin ZHANG 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2022年第2期282-303,共22页
For some infectious diseases such as mumps,HBV,there is evidence showing that vaccinated individuals always lose their immunity at different rates depending on the inoculation time.In this paper,we propose an age-stru... For some infectious diseases such as mumps,HBV,there is evidence showing that vaccinated individuals always lose their immunity at different rates depending on the inoculation time.In this paper,we propose an age-structured epidemic model using a step function to describe the rate at which vaccinated individuals lose immunity and reduce the age-structured epidemic model to the delay differential model.For the age-structured model,we consider the positivity,boundedness,and compactness of the semiflow and study global stability of equilibria by constructing appropriate Lyapunov functionals.Moreover,for the reduced delay differential equation model,we study the existence of the endemic equilibrium and prove the global stability of equilibria.Finally,some numerical simulations are provided to support our theoretical results and a brief discussion is given. 展开更多
关键词 VACCINATION age-structured epidemic model delay differential equation model STABILITY Lyapunov functional
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Precise control of a magnetically suspended double-gimbal control moment gyroscope using differential geometry decoupling method 被引量:3
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作者 Chen Xiaocen Chen Maoyin 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2013年第4期1017-1028,共12页
Precise control of a magnetically suspended double-gimbal control moment gyroscope (MSDGCMG) is of vital importance and challenge to the attitude positioning of spacecraft owing to its multivariable, nonlinear and s... Precise control of a magnetically suspended double-gimbal control moment gyroscope (MSDGCMG) is of vital importance and challenge to the attitude positioning of spacecraft owing to its multivariable, nonlinear and strong coupled properties. This paper proposes a novel linearization and decoupling method based on differential geometry theory and combines it with the internal model controller (IMC) to guarantee the system robustness to the external disturbance and parameter uncertainty. Furthermore, by introducing the dynamic compensation for the inner-gimbal rate-servo system and the magnetically suspended rotor (MSR) system only, we can eliminate the influence of the unmodeled dynamics to the decoupling control accuracy as well as save costs and inhibit noises effectively. The simulation results verify the nice decoupling and robustness performance of the system using the proposed method. 展开更多
关键词 differential geometry decoupling Dynamic compensation Internal model controller MSDGCMG Spacecraft control
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A Teletraffic Model for Service Differentiation in OPS Networks
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作者 H. Overby N. Stol 《光学学报》 EI CAS CSCD 北大核心 2003年第S1期677-678,共2页
This paper present a formal teletraffic model for service diferentiation in optical packet switched networks by utilizing the wavelength domain.Expressions for the time congestion are derived.Simulation results are al... This paper present a formal teletraffic model for service diferentiation in optical packet switched networks by utilizing the wavelength domain.Expressions for the time congestion are derived.Simulation results are also reported. 展开更多
关键词 OPS for in A Teletraffic model for Service Differentiation in OPS Networks
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NUMERICAL SIMULATION AND EXPERIMENTAL INVESTIGATION OF THE GUIDE-VANE FLOW AND THE INFLUENCE FROM THE LEAKAGE FLOW 被引量:2
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作者 LiaoWei-li LiJian-zhong 《Journal of Hydrodynamics》 SCIE EI CSCD 2003年第1期103-110,共8页
This paper presents numerical and experimental results of the flow in the tipclearance region of the guide vane row in hydraulic turbine. The 3-D Navier-Stokes equations wereemployed to model the flow in end clearance... This paper presents numerical and experimental results of the flow in the tipclearance region of the guide vane row in hydraulic turbine. The 3-D Navier-Stokes equations wereemployed to model the flow in end clearance region of guide vane cascade, the Reynolds stressdifferential model was used for turbulence closure, and the body-fitted curvilinear coordinates andthe SIMPLE! algorithm were adopted. The governing equations were discretized with the non-staggeredgrids by means of the finite volume method. Detailed comparison of hydrodynamical characteristics ofguide vane in hydraulic turbine with or without tip gap was made. Special attention was paid to theinfluence of leakage flow on the main flow and to the movement of tip leakage flow in the end guidevane. The position and strength of the roll-vortex on the sides of guide vane in were determined.The numerical solutions agree with the experimental results obtained by particle image ve-locimetry.The results help to clarify the loss, wear and cavi-tation erosion between the guide vane andrings, especially for those used in the Yellow River which has a high sediment content. 展开更多
关键词 leakage flow guide vane reynolds stress differential model
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Optimization of ohmic contact for InP-based transferred electronic devices
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作者 武德起 丁武昌 +3 位作者 杨姗姗 贾锐 金智 刘新宇 《Journal of Semiconductors》 EI CAS CSCD 2014年第3期158-162,共5页
The effect of the annealing time and annealing temperature on Ni/Ge/Au electrode contacts deposited on the n-type InP contact layer has been studied using a circular transmission line model. The minimum specific conta... The effect of the annealing time and annealing temperature on Ni/Ge/Au electrode contacts deposited on the n-type InP contact layer has been studied using a circular transmission line model. The minimum specific contact resistance of 3.210 7 cm2was achieved on the low-doped n-type InP contact layer with a 40 s anneal at 425 ℃. In order to improve the ohmic contact and reduce the difficulty in the fabrication of the high doped InP epi-layer, the doping concentration in the InP contact layer was chosen to be 51018cm 3in the fabrication of transferred electronic devices. Excellent differential negative resistance properties were obtained by an electron beam evaporating the Ni/Ge/Au/Ge/Ni/Au composite electrode on an InP epi-layer with a 60 s anneal at 380 ℃. 展开更多
关键词 circular transmission line model specific contact resistance InP transferred electronic devices differential negative resistance
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