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Simulation of two-dimensional interior ballistics model of solid propellant electrothermal-chem ical launch with discharge rod plasma generator 被引量:6
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作者 Yan-jie Ni Yong Jin +3 位作者 Niankai Cheng Chun-xia Yang Hai-yuan Li Bao-ming Li 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2017年第4期249-256,共8页
Instead of the capillary plasma generator(CPG),a discharge rod plasma generator(DRPG)is used in the30 mm electrothermal-chemical(ETC)gun to improve the ignition uniformity of the solid propellant.An axisymmetric two-d... Instead of the capillary plasma generator(CPG),a discharge rod plasma generator(DRPG)is used in the30 mm electrothermal-chemical(ETC)gun to improve the ignition uniformity of the solid propellant.An axisymmetric two-dimensional interior ballistics model of the solid propellant ETC gun(2D-IB-SPETCG)is presented to describe the process of the ETC launch.Both calculated pressure and projectile muzzle velocity accord well with the experimental results.The feasibility of the 2D-IB-SPETCG model is proved.Depending on the experimental data and initial parameters,detailed distribution of the ballistics parameters can be simulated.With the distribution of pressure and temperature of the gas phase and the propellant,the influence of plasma during the ignition process can be analyzed.Because of the radial flowing plasma,the propellant in the area of the DRPG is ignited within 0.01 ms,while all propellant in the chamber is ignited within 0.09 ms.The radial ignition delay time is much less than the axial delay time.During the ignition process,the radial pressure difference is less than 5 MPa at the place 0.025 m away from the breech.The radial ignition uniformity is proved.The temperature of the gas increases from several thousand K(conventional ignition)to several ten thousand K(plasma ignition).Compare the distribution of the density and temperature of the gas,we know that low density and high temperature gas appears near the exits of the DRPG,while high density and low temperature gas appears at the wall near the breech.The simulation of the 2D-IB-SPETCG model is an effective way to investigate the interior ballistics process of the ETC launch.The 2D-IB-SPETC model can be used for prediction and improvement of experiments. 展开更多
关键词 Electrothermal-chemical LAUNCH Interior BALLISTICS simulation Two-phase flow two-dimensional model
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Device simulation of quasi-two-dimensional perovskite/silicon tandem solar cells towards 30%-efficiency
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作者 Xiao-Ping Xie Qian-Yu Bai +8 位作者 Gang Liu Peng Dong Da-Wei Liu Yu-Feng Ni Chen-Bo Liu He Xi Wei-Dong Zhu Da-Zheng Chen Chun-Fu Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第10期592-598,共7页
Perovskite/silicon(Si) tandem solar cells have been recognized as the next-generation photovoltaic technology with efficiency over 30% and low cost. However, the intrinsic instability of traditional three-dimensional(... Perovskite/silicon(Si) tandem solar cells have been recognized as the next-generation photovoltaic technology with efficiency over 30% and low cost. However, the intrinsic instability of traditional three-dimensional(3D) hybrid perovskite seriously hinders the lifetimes of tandem devices. In this work, the quasi-two-dimensional(2D)(BA)_(2)(MA)_(n-1)Pbn I_(3n+1)(n = 1, 2, 3, 4, 5)(where MA denotes methylammonium and BA represents butylammonium), with senior stability and wider bandgap, are first used as an absorber of semitransparent top perovskite solar cells(PSCs) to construct a fourterminal(4T) tandem devices with a bottom Si-heterojunction cell. The device model is established by Silvaco Atlas based on experimental parameters. Simulation results show that in the optimized tandem device, the top cell(n = 4) obtains a power conversion efficiency(PCE) of 17.39% and the Si bottom cell shows a PCE of 11.44%, thus an overall PCE of 28.83%. Furthermore, by introducing a 90-nm lithium fluoride(LiF) anti-reflection layer to reduce the surface reflection loss, the current density(J_(sc)) of the top cell is enhanced from 15.56 m A/cm^(2) to 17.09 m A/cm^(2), the corresponding PCE reaches 19.05%, and the tandem PCE increases to 30.58%. Simultaneously, in the cases of n = 3, 4, and 5, all the tandem PCEs exceed the limiting theoretical efficiency of Si cells. Therefore, the 4T quasi-2D perovskite/Si devices provide a more cost-effective tandem strategy and long-term stability solutions. 展开更多
关键词 two-dimensional device simulation antireflection layers tandem solar cells
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Two-Dimensional Fluid Simulation of Collisional Plasma Sheath over rf Powered Electrode with Cylindrical Hole
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作者 侯璐景 王友年 Z.L.Miskvic 《Plasma Science and Technology》 SCIE EI CAS CSCD 2004年第4期2404-2410,共7页
The characteristics of collisional radio-frequency (rf) sheath dynamics over an elec-trode with a cylindrical hole is simulated by means of a self-consistent model which consists of two-dimensional time-dependent flui... The characteristics of collisional radio-frequency (rf) sheath dynamics over an elec-trode with a cylindrical hole is simulated by means of a self-consistent model which consists of two-dimensional time-dependent fluid equations coupled with Poisson equation. In addition, an equivalent-circuit model is coupled to the fluid equations in order to self-consistently determine re-lationship between the instantaneous potential at the rf-biased electrode and the sheath thickness. Two-dimensional profiles of the potential, the ion fluid velocity, and the distributions of the ion and electron densities within the sheath are computed under various discharge conditions, such as the discharge powers and the gas pressures. The results show that the existence of the cylindrical hole on the electrode significantly affects the sheath structure and generates a potential trap in the horizontal direction, which is particularly strong when the sheath thickness is comparable to the depth of the hole. Moreover, it is found that the collisional effects have a significant influence on the sheath characteristics. 展开更多
关键词 two-dimensional sheath numerical simulation dusty plasma
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Two-Dimensional Simulation of a Dual Frequency Sheath Near an Electrode with a Cylindrical Hole
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作者 戴忠玲 刘传生 王友年 《Plasma Science and Technology》 SCIE EI CAS CSCD 2009年第3期283-289,共7页
The characteristics of a collisional dual frequency (DF) sheath near an electrode with a cylindrical hole are studied by utilizing a two-dimensional model which includes time-dependent fluid equations coupled with t... The characteristics of a collisional dual frequency (DF) sheath near an electrode with a cylindrical hole are studied by utilizing a two-dimensional model which includes time-dependent fluid equations coupled with the Poisson equation and an equivalent-circuit model, The effects of the gas pressure on the two-dimensional profiles of the potential, electric field, ion fluid velocity in a DF sheath are investigated. The simulation results show that the cylindrical hole on the electrode has a significant influence on the DF sheath structure, i.e., the sheath profile tends to wrap around the contour of the hole feature. Moreover, it is shown that the structure of the DF sheath is different from that of a single frequency (SF) sheath because the profile of the DF sheath is modulated by the combination of the high and low frequency sources. In addition the characteristics of the DF sheath are obviously affected by the collisional effects in the DF sheath. 展开更多
关键词 dual frequency sheath two-dimensional numerical simulation
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Effect of Parallel-Plate Geometry on Mode Transition Behavior in Argon Microplasmas: Two-Dimensional Simulation
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作者 Xiang-Mei Liu Yuan-Hong Song +1 位作者 Wei Jiang Wen-Zhu Jia 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第4期66-69,共4页
A two-dimensional self-consistent fluid model is employed to investigate radio-frequency process parameters on the plasma properties in Ar microdischarges. The neutral gas density and temperature balance equations are... A two-dimensional self-consistent fluid model is employed to investigate radio-frequency process parameters on the plasma properties in Ar microdischarges. The neutral gas density and temperature balance equations are taken into account. We mainly investigate the effect of the electrode gap on the spatial distribution of the electron density and electron temperature profiles, due to a mode transition from the regime(secondary electrons emission is responsible for the significant ionization) to the regime(sheath oscillations and bulk electrons are responsible for sustaining discharge) induced by a sudden decrease of electron density and electron temperature.The pressure, radio-frequency sources frequency and voltage effects on the electron density are also elaborately investigated. 展开更多
关键词 two-dimensional simulation
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Multi-parameter numerical simulation of dynamic monitoring of rock deformation in deep mining 被引量:3
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作者 Li Juanjuan Hu Mingshun +3 位作者 Ding Enjie Kong Wei Pan Dongming Chen Shenen 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第5期851-855,共5页
The level of deformation development of surrounding rocks is a vital predictor to evaluate impending coal mine disasters and it is important to establish accurate measurements of the deformed status to ensure coal min... The level of deformation development of surrounding rocks is a vital predictor to evaluate impending coal mine disasters and it is important to establish accurate measurements of the deformed status to ensure coal mine safety. Traditional deformation monitoring methods are mostly based on single parameter, in this paper, multiple approaches are integrated: firstly, both electric and elastic models are established,from which electric field distribution and seismic wave recording are calculated and finally, the resistivity profiles and source position information are determined using inversion methods, from which then the deformation and failure of mine floor are evaluated. According to the inversion results of both electric and seismic field signals, multiple-parameter dynamic monitoring of surrounding rock deformation in deep mine can be performed. The methodology is validated using numerical simulation results which shows that the multi-parameter dynamic monitoring methods have better results for surrounding rock deformation in deep mine monitoring than single parameter methods. 展开更多
关键词 Dynamic monitoring Electric numerical simulation Elastic numerical simulation inversion methods
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Sweet spot prediction in tight sandstone reservoir based on well-bore rock physical simulation 被引量:6
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作者 Hai-ting Zhou De-yong Li +2 位作者 Xian-tai Liu Yu-shan Du Wei Gong 《Petroleum Science》 SCIE CAS CSCD 2019年第6期1285-1300,共16页
To establish the relationship among reservoir characteristics and rock physical parameters,we construct the well-bore rock physical models firstly,considering the influence factors,such as mineral composition,shale co... To establish the relationship among reservoir characteristics and rock physical parameters,we construct the well-bore rock physical models firstly,considering the influence factors,such as mineral composition,shale content,porosity,fluid type and saturation.Then with analyzing the change rules of elastic parameters along with the above influence factors and the cross-plots among elastic parameters,the sensitive elastic parameters of tight sandstone reservoir are determined,and the rock physics template of sweet spot is constructed to guide pre-stack seismic inversion.The results show that velocity ratio and Poisson impedance are the most sensitive elastic parameters to indicate the lithologic and gas-bearing properties of sweet spot in tight sandstone reservoir.The high-quality sweet spot is characterized by the lower velocity ratio and Poisson impedance.Finally,the actual seismic data are selected to predict the sweet spots in tight sandstone gas reservoirs,so as to verify the validity of the rock physical simulation results.The significant consistency between the relative logging curves and inversion results in different wells implies that the utilization of well-bore rock physical simulation can guide the prediction of sweet spot in tight sandstone gas reservoirs. 展开更多
关键词 Tight sandstone reservoir Sweet spot Sensitive elastic parameter Well-bore rock physical simulation Rock physics template Pre-stack seismic inversion
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Two-Dimensional Euler Adaptive Mesh Method on Detonation 被引量:1
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作者 郝鹏程 冯其京 姚雯 《Journal of Beijing Institute of Technology》 EI CAS 2009年第2期141-145,共5页
The adaptive mesh refinement (AMR) method is applied in the 2-D Euler multi-component elasticplastic hydrodynamics code (MEPH2Y). It is applied on detonation. Firstly, the AMR method is described, including a cons... The adaptive mesh refinement (AMR) method is applied in the 2-D Euler multi-component elasticplastic hydrodynamics code (MEPH2Y). It is applied on detonation. Firstly, the AMR method is described, including a conservative spatial interpolation, the time integration methodology with the adapitve time increment and an adaptive computational region method. The advantage of AMR technique is exhibited by numerical examples, including the 1-D C-J detonation and the 2-D implosion ignited from a single point. Results show that AMR can promote the computational efficiency, keeping the accuracy in interesting regions. 展开更多
关键词 adaptive mesh refinement (AMR) DETONATION two-dimension EULER numerical simulation
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Simulation method for measurement of the cross-section of the^(14)N(n,a)^(11)B reaction using a gridded ionization chamber 被引量:2
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作者 Yi-Wei Hu Hao-Yu Jiang +5 位作者 Zeng-Qi Cui Jie Liu Hao-Fan Bai Huai-Yong Bai Jin-Xiang Chen Guo-Hui Zhang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2021年第8期1-11,共11页
A simulation method for measurement of the cross-section of the^(14)N(n,a)^(11)B reaction with gas and solid samples using a gridded ionization chamber(GIC)has been established.Using the simulation,the experimental sp... A simulation method for measurement of the cross-section of the^(14)N(n,a)^(11)B reaction with gas and solid samples using a gridded ionization chamber(GIC)has been established.Using the simulation,the experimental spectra of both^(14)N(n,a)^(11)B events and background from other reactions can be predicted,and the experimental scheme can be optimized.According to the simulation results,the optimal experimental parameters,including the pressure of the working gas and the compositions of the working gas and the sample,can be determined.In addition,the simulation results can be used to determine the valid event area and calculate the detection efficiency for valid events.A measurement of the cross-sections of the^(14)N(n,a)^(11)B reaction at E_(n)=4.25,4.50,4.75,5.00,5.25,and 5.50 MeV,based on the 4.5-MV Van de Graff accelerator at Peking University(PKU)using a GIC as the detector for the outgoing a particles,has been performed.The good agreement of the spectra from the simulation and experiment demonstrated the universality of this simulation method,which can be used to accurately measure neutroninduced light-charged particle emission reactions. 展开更多
关键词 Gridded ionization chamber Monte Carlo simulation Cathode–anode two-dimensional spectrum ^(14)N(n a)^(11)B reaction
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Performance comparison of several optimization algorithms in matched field inversion
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作者 ZOU Shixin, YANG Kun-de, MA Yuanliang (Northwestern Polytechnic University, Xi’an 710072, China) 《声学技术》 CSCD 2004年第S1期23-28,共6页
Optimization efficiencies and mechanisms of simulated annealing, genetic algorithm, differential evolution and downhill simplex differential evolution are compared and analyzed. Simulated annealing and genetic algorit... Optimization efficiencies and mechanisms of simulated annealing, genetic algorithm, differential evolution and downhill simplex differential evolution are compared and analyzed. Simulated annealing and genetic algorithm use a directed random process to search the parameter space for an optimal solution. They include the ability to avoid local minima, but as no gradient information is used, searches may be relatively inefficient. Differential evolution uses information from a distance and azimuth between individuals of a population to search the parameter space, the initial search is effective, but the search speed decreases quickly because differential information between the individuals of population vanishes. Local downhill simplex and global differential evolution methods are developed separately, and combined to produce a hybrid downhill simplex differential evolution algorithm. The hybrid algorithm is sensitive to gradients of the object function and search of the parameter space is effective. These algorithms are applied to the matched field inversion with synthetic data. Optimal values of the parameters, the final values of object function and inversion time is presented and compared. 展开更多
关键词 simulATED ANNEALING GENETIC algorithm DIFFERENTIAL evolution matched field inversion
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Exact solutions and linear stability analysis for two-dimensional Ablowitz Ladik equation
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作者 张金良 王红县 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第4期300-309,共10页
The Ablowitz-Ladik equation is a very important model in nonlinear mathematical physics. In this paper, the hyper- bolic function solitary wave solutions, the trigonometric function periodic wave solutions, and the ra... The Ablowitz-Ladik equation is a very important model in nonlinear mathematical physics. In this paper, the hyper- bolic function solitary wave solutions, the trigonometric function periodic wave solutions, and the rational wave solutions with more arbitrary parameters of two-dimensional Ablowitz-Ladik equation are derived by using the (GI/G)-expansion method, and the effects of the parameters (including the coupling constant and other parameters) on the linear stability of the exact solutions are analysed and numerically simulated. 展开更多
关键词 two-dimensional Ablowitz-Ladik equation linear stability exact solution numerical simulation
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Stochastic Techniques of Seismic Inversion and Reservoir Properties Prediction
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作者 Denis Kashcheev Dmitry Kirnos 《岩性油气藏》 CSCD 2010年第F07期93-96,108,共5页
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近活动断裂带长大深埋高铁隧道地应力特征分析
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作者 姜浩 严健 +3 位作者 韦远圳 金文睿 李增 曹嘉心 《铁道勘察》 2025年第1期112-119,共8页
渝昆高铁是我国“八纵八横”重要铁路干线,铁路沿线地质环境复杂,特别是深埋长大隧道地应力复杂,隧道施工中围岩结构安全挑战严峻。采用文献调研、三维地应力反演和理论分析的方法,分析彝良—鲁甸地区2座长大深埋高铁隧道地应力分布特... 渝昆高铁是我国“八纵八横”重要铁路干线,铁路沿线地质环境复杂,特别是深埋长大隧道地应力复杂,隧道施工中围岩结构安全挑战严峻。采用文献调研、三维地应力反演和理论分析的方法,分析彝良—鲁甸地区2座长大深埋高铁隧道地应力分布特征。研究表明,(1)彝良、鲁甸隧道最大水平主应力呈现“北强南弱”的规律,推测为印度板块与亚欧板块碰撞产生的构造应力由高原中部向南逐渐减弱导致;(2)彝良、鲁甸隧道地应力分布表现为:彝良隧道最大水平主应力为15.6~26.8 MPa,竖向主应力为9.5~26.8 MPa;鲁甸隧道最大水平主应力10.9~15.6 MPa,竖向主应力为1.8~11.7 MPa;(3)彝良隧道侧压力系数在0.97~2.1之间,在地层浅部地应力由构造应力主导,地层深部由自重应力主导;鲁甸隧道侧压力系数在1.1~6.9之间,地应力由构造应力主导。 展开更多
关键词 高速铁路 隧道工程 地应力 反演 断裂带 数值模拟
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小天体光变曲线观测光学仿真系统
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作者 雷开宇 史弦 +1 位作者 武延鹏 李林 《空间控制技术与应用》 北大核心 2025年第1期54-64,共11页
小天体光变曲线能够反映出目标的形状、自转特性等信息.在我国未来的深空探测任务中,需要通过光变观测来获取目标的先验性质.针对上述需求,本文构建了一种面向真实观测场景的光变观测仿真系统,该系统结合了基于光电链路的恒星背景仿真... 小天体光变曲线能够反映出目标的形状、自转特性等信息.在我国未来的深空探测任务中,需要通过光变观测来获取目标的先验性质.针对上述需求,本文构建了一种面向真实观测场景的光变观测仿真系统,该系统结合了基于光电链路的恒星背景仿真与基于计算机图形学的场景仿真,能够对光变观测图像进行模拟.在获得仿真图像后,从仿真图像中计算出目标光变曲线,并进行反演与分析,实现从观测到性质分析的全功能覆盖.经过实验,本文系统得到的仿真光变的反演结果与真实观测数据的反演结果较为接近,能够应用于飞行器在轨光变观测的研究中,为飞行器光变观测任务规划提供了思路. 展开更多
关键词 小天体 光变反演 场景仿真 深空探测
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基于微观形貌的逆偏析形成机理的数值模拟分析
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作者 张宇 朱宝丰 +3 位作者 张士杰 张冰 张思雨 李日 《材料科学与工艺》 北大核心 2025年第1期31-40,共10页
铸件中逆偏析的存在会显著降低铸件的力学性能和切削加工性能,因此研究逆偏析的形成机理具有重要意义。采用微观尺度的元胞自动机(CA)耦合格子玻尔兹曼方法(LBM)的模型,以Al-4.7wt.%Cu合金为例,分别模拟了计算域的全域柱状晶凝固、柱状... 铸件中逆偏析的存在会显著降低铸件的力学性能和切削加工性能,因此研究逆偏析的形成机理具有重要意义。采用微观尺度的元胞自动机(CA)耦合格子玻尔兹曼方法(LBM)的模型,以Al-4.7wt.%Cu合金为例,分别模拟了计算域的全域柱状晶凝固、柱状晶向等轴晶转变(CET)的凝固和全域等轴晶凝固,并且分析了逆偏析的形成机理。研究发现,计算域边界较低的温度以及柱状晶发达的二次枝晶对含有溶质的熔体的分割阻碍是逆偏析形成的主要原因。计算域边界降温速度越快,逆偏析程度就越大;柱状晶对含有溶质的熔体的分割阻碍作用比中心等轴晶要大,凝固组织全部为柱状晶时,逆偏析最为严重,凝固组织同时含有柱状晶和等轴晶时,逆偏析次之,凝固组织全部为等轴晶时逆偏析最轻。计算域中心溶液受重力影响沿流场流向计算域底部的枝晶间隙,使计算域底部逆偏析程度大于其他部分。在铸锭凝固过程中可以考虑增加机械或者电磁搅拌、增大等轴晶区面积或者降低散热速率来降低逆偏析对铸锭的不利影响。 展开更多
关键词 逆偏析 元胞自动机 格子玻尔兹曼 微观形貌 数值模拟 AL-CU合金
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车载逆变电源的Saber与Simulink联合仿真 被引量:10
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作者 曾伟 王君艳 《现代电子技术》 2012年第12期186-188,191,共4页
在此运用软件Saber和Matlab/Simulink对车载逆变电源系统进行了联合仿真,得到具有闭环控制功能的车载逆变电源系统的实时仿真结果。通过仿真结果表明利用Saber和Matlab/Simulink软件的联合仿真,可以实现精确的器件模型,搭建控制系统更方... 在此运用软件Saber和Matlab/Simulink对车载逆变电源系统进行了联合仿真,得到具有闭环控制功能的车载逆变电源系统的实时仿真结果。通过仿真结果表明利用Saber和Matlab/Simulink软件的联合仿真,可以实现精确的器件模型,搭建控制系统更方便,保证了系统仿真的收敛性,简化了系统仿真的难度,缩短了仿真时间。 展开更多
关键词 车载电源 Saber矩阵实验室 联合仿真
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贝叶斯突水水源判别与反向水文地球化学模拟的含水层水力分析
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作者 郑剑 陈陆望 +3 位作者 张杰 张苗 郑忻 胡永胜 《合肥工业大学学报(自然科学版)》 北大核心 2025年第2期203-211,共9页
为探究杨柳煤矿主要突水含水层之间的水力联系,文章根据杨柳煤矿松散层第4含水层(简称“四含”或“Ⅰ”含水层)、二叠系煤系砂岩裂隙含水层(简称“煤系”或“Ⅱ”含水层)和石炭系太原组灰岩岩溶裂隙含水层(简称“太灰”或“Ⅲ”含水层)... 为探究杨柳煤矿主要突水含水层之间的水力联系,文章根据杨柳煤矿松散层第4含水层(简称“四含”或“Ⅰ”含水层)、二叠系煤系砂岩裂隙含水层(简称“煤系”或“Ⅱ”含水层)和石炭系太原组灰岩岩溶裂隙含水层(简称“太灰”或“Ⅲ”含水层)的地下水化学数据建立贝叶斯突水水源判别模型,并结合地质与构造条件,对3个突水含水层之间的补给关系、径流路径以及径流路径中的水-岩作用进行研究。结果表明:杨柳煤矿大部分区域不同含水层之间的水力联系较弱,在矿井西北部四含与煤系、煤系与太灰之间存在一定程度的水力联系;四含水通过西风井附近煤系砂岩露头向煤系补给,煤系水通过DF25、DF10断层向太灰补给,太灰水通过GF383断层向煤系补给。误判水样的反向水文地球化学模拟结果定量验证了离子比例分析揭示的径流路径中的水-岩作用,进一步证明了含水层之间的补给关系。该研究成果为快速判断矿区不同含水层之间的补给关系提供了技术参考。 展开更多
关键词 贝叶斯判别 反向水文地球化学模拟 水力联系 水-岩作用 杨柳煤矿
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基于参数分析与智能优化的导叶式混流泵多工况优化
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作者 丁征 袁建平 +3 位作者 陈颖俊 戴秋萍 陈松山 王梦成 《排灌机械工程学报》 北大核心 2025年第4期348-356,共9页
为进一步研究混流泵的多工况优化,以一中比转数导叶式混流泵叶轮为研究对象,以反问题设计方法为基础,以轮毂及轮缘处载荷控制参数NC_(h),ND_(h),K_(h),NC_(s),ND_(s)和K_(s)为设计参数,以0.8 Q_(des)和1.1 Q_(des)(Q_(des)为设计流量)... 为进一步研究混流泵的多工况优化,以一中比转数导叶式混流泵叶轮为研究对象,以反问题设计方法为基础,以轮毂及轮缘处载荷控制参数NC_(h),ND_(h),K_(h),NC_(s),ND_(s)和K_(s)为设计参数,以0.8 Q_(des)和1.1 Q_(des)(Q_(des)为设计流量)处效率为优化目标,以1.0 Q_(des)处扬程为约束条件,结合正交试验设计、最优拉丁超立方抽样法、径向基神经网络和非支配排序遗传算法,在参数分析的基础上对其开展多工况优化研究.结果表明:参数ND_(h),K_(h),NC_(s),ND_(s)和K_(s)对0.8 Q_(des)和1.1 Q_(des)工况处效率均具有显著影响,在优化设计中应该被重点考虑;轮毂及轮缘处后加载有利于小流量工况下效率的提升,而两者前加载则有利于大流量工况下效率的提升;优化后模型在0.8 Q_(des),1.0 Q_(des)和1.1 Q_(des)处效率分别为82.32%,88.13%和86.50%,较原始模型分别提升了0.73%,0.99%和1.55%.内流分析表明,叶轮进口处二次流的改善及导叶内湍动强度的降低是优化后模型效率提升的根本原因. 展开更多
关键词 导叶式混流泵 数值模拟 反问题设计 参数分析 智能优化
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高速运动对ISAR成像的影响
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作者 吴舟 王军锋 《制导与引信》 2025年第1期52-60,共9页
逆合成孔径雷达(inverse synthetic aperture radar,ISAR)传统成像算法基于“走-停”假设,缺少目标或平台高速运动对ISAR成像影响的理论分析和精确仿真。针对该问题,首先对目标或平台高速运动条件下的ISAR成像进行了理论分析。分析结果... 逆合成孔径雷达(inverse synthetic aperture radar,ISAR)传统成像算法基于“走-停”假设,缺少目标或平台高速运动对ISAR成像影响的理论分析和精确仿真。针对该问题,首先对目标或平台高速运动条件下的ISAR成像进行了理论分析。分析结果表明,当ISAR发射线性调频信号时,回波信号仍可近似为线性调频信号,只是中心频率和调频斜率会变化,从而导致距离向偏移和模糊。然后提出了一种目标或平台高速运动时ISAR回波信号的精确仿真方法,通过建立平台、目标、电磁波的联动方程,精准体现高速运动对ISAR回波信号的影响,进而进行成像处理。仿真结果证明了回波信号仿真方法的有效性,同时证明了目标或平台高速运动时经典成像算法确实会导致距离向的偏移和模糊现象,但在一般情况下该现象并不明显。 展开更多
关键词 高速运动 逆合成孔径雷达 “走-停”假设 精确仿真
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Dynamic Analysis of High-Speed Boat Motion Simulator by a Novel 3-DoF Parallel Mechanism with Prismatic Actuators Based on Seakeeping Trial 被引量:3
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作者 Ali Pirouzfar Javad Enferadi Masoud Dehghan 《Journal of Marine Science and Application》 CSCD 2018年第2期178-191,共14页
In this study,we focused on a novel parallel mechanism for utilizing the motion simulator of a high-speed boat(HSB).First,we expressed the real behavior of the HSB based on a seakeeping trial.For this purpose,we recor... In this study,we focused on a novel parallel mechanism for utilizing the motion simulator of a high-speed boat(HSB).First,we expressed the real behavior of the HSB based on a seakeeping trial.For this purpose,we recorded the motion parameters of the HSB by gyroscope and accelerometer sensors,while using a special data acquisition technique.Additionally,a Chebychev highpass filter was applied as a noise filter to the accelerometer sensor.Then,a novel 3 degrees of freedom(DoF)parallel mechanism(1T2R)with prismatic actuators is proposed and analyses were performed on its inverse kinematics,velocity,and acceleration.Finally,the inverse dynamic analysis is presented by the principle of virtual work,and the validation of the analytical equations was compared by the ADAMS simulation software package.Additionally,according to the recorded experimental data of the HSB,the feasibility of the proposed novel parallel mechanism motion simulator of the HSB,as well as the necessity of using of the washout filters,was explored. 展开更多
关键词 MOTION simulators Parallel mechanism HIGH-SPEED BOAT SEAKEEPING TRIAL inversE dynamics Virtualwork
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