期刊文献+
共找到154,287篇文章
< 1 2 250 >
每页显示 20 50 100
Experimental Study on Dynamic Mechanical Properties of Sprayed Concrete-Surrounding Rock Combined Body 预览
1
作者 Dongming Guo Pengyang Yan +2 位作者 Longfei Fan Yingshi Zhang Xiaoye Wang 《北京理工大学学报:英文版》 EI CAS 2019年第2期278-285,共8页
To investigate the dynamic response problem of the double medium formed by the adherence of sprayed concrete and surrounding rock in the tunnel,a split Hopkinson pressure bar of 75 mm in diameter was adopted at the ag... To investigate the dynamic response problem of the double medium formed by the adherence of sprayed concrete and surrounding rock in the tunnel,a split Hopkinson pressure bar of 75 mm in diameter was adopted at the ages of 3,7 and 10 d.Experimental results showed that dynamic compressive strength and dynamic increase factors(DIF)of the combined bodies increase with the strain rate.With the growth of strain rate,the critical strain of the combined bodies first increases,then deceases.Furthermore,the combined bodies of 3 d reveal the plastic property and brittle property for 7 d and 10 d when the strain rate is over 80/s.The failure characteristic of the sprayed concrete changes from tearing strain damage to crushing damage as the growth of strain rate,and the failure characteristic of rock presents the tensile failure mode as demonstrated by the scanning electron microscope(SEM). 展开更多
关键词 SPRAYED concrete-surrounding rock COMBINED BODY DYNAMIC compressive strength DYNAMIC increase factors critical strain failure modes
在线阅读 免费下载
Fuzzy Behavior-based Control of Three Wheeled Omnidirectional Mobile Robot
2
作者 Nacer Hacene Boubekeur Mendil 《国际自动化与计算杂志:英文版》 EI CSCD 2019年第2期163-185,共23页
In this paper, a fuzzy behavior-based approach for a three wheeled omnidirectional mobile robot (TWOMR) navigation has been proposed. The robot has to track either static or dynamic target while avoiding either static... In this paper, a fuzzy behavior-based approach for a three wheeled omnidirectional mobile robot (TWOMR) navigation has been proposed. The robot has to track either static or dynamic target while avoiding either static or dynamic obstacles along its path. A simple controller design is adopted, and to do so, two fuzzy behaviors "Track the Target" and "Avoid Obstacles and Wall Following" are considered based on reduced rule bases (six and five rules respectively). This strategy employs a system of five ultrasonic sensors which provide the necessary information about obstacles in the environment. Simulation platform was designed to demonstrate the effectiveness of the proposed approach. 展开更多
关键词 THREE WHEELED OMNIDIRECTIONAL mobile robot (TWOMR) autonomous navigation obstacle AVOIDANCE FUZZY behaviorbased control DYNAMIC target DYNAMIC environment
Impact of recycling improvement on the life cycle of phosphorus
3
作者 Mohammad El Wali Saeed Rahimpour Golroudbary Andrzej Kraslawski 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第5期1219-1229,共11页
Access to natural resources is increasingly more difficult and more costly, partly due to their economic significance and to continuous increase of their global consumption in the recent years. In the case of phosphor... Access to natural resources is increasingly more difficult and more costly, partly due to their economic significance and to continuous increase of their global consumption in the recent years. In the case of phosphorus (P), which is a critical raw material, geological distribution of its primary nonrenewable source (phosphate rock) is concentrated in particular regions leading to high supply risk of this raw material. In Europe (EU-28), where phosphate rock reserves are scarce, import of phosphorus has been the main source of supply. It means that Europe relies highly on the foreign exporters. From decision makers' perspective, recycling of phosphorus was taken into account as one of the possible solutions to decrease the dependence on imports and extraction of reserves. The question, however, is to what extent does the recycling of phosphorus help in reducing the reliance on typical supply resources? Hence, the main objective of this paper is to quantify the dynamic flow of phosphorus and show potential benefits of its recycling in Europe. This article presents a system dynamics model for representation of the element P flow and helps to quantify to what extent the recycled phosphorus could mitigate its criticality. Analysis of the results supports previous studies indicating the high reliance ofEU on P imports, estimating around 96% as the reliance percentage on imports. The results imply that improving P recycling has the potential to decrease the level of P imports to a certain extent, which may reach 79%. 展开更多
关键词 CRITICAL material PHOSPHORUS DYNAMIC MODELLING DYNAMIC simulation RECOVERY RECYCLING
Comprehensive analysis of the influence of structural and dynamic parameters on the accuracy of nano-precision positioning stages
4
作者 Chengyuan LIANG Fang YUAN +3 位作者 Xuedong CHEN Wei JIANG Lizhan ZENG Xin LUO 《机械工程前沿:英文版》 CSCD 2019年第3期255-272,共18页
Nano-precision positioning stages are characterized by rigid-flexible coupling systems. The complex dynamic characteristics of mechanical structure of a stage, which are determined by structural and dynamic parameters... Nano-precision positioning stages are characterized by rigid-flexible coupling systems. The complex dynamic characteristics of mechanical structure of a stage, which are determined by structural and dynamic parameters, exert a serious influence on the accuracy of its motion and measurement. Systematic evaluation of such influence is essential for the design and improvement of stages. A systematic approach to modeling the dynamic accuracy of a nano-precision positioning stage is developed in this work by integrating a multi-rigid-body dynamic model of the mechanical system and measurement system models. The influence of structural and dynamic parameters, including aerostatic bearing configurations, motion plane errors, foundation vibrations, and positions of the acting points of driving forces, on dynamic accuracy is investigated by adopting the H-type configured stage as an example. The approach is programmed and integrated into a software framework that supports the dynamic design of nano-precision positioning stages. The software framework is then applied to the design of a nano-precision positioning stage used in a packaging lithography machine. 展开更多
关键词 nano-precision POSITIONING stage analysis and design structural and DYNAMIC parameters DYNAMIC ACCURACY systematic modeling
The effect of monosaccharides on self-assembly of benzenetricarboxamides
5
作者 Jue Wang Wenjing Qi Guosong Chen 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第3期587-591,共5页
The interaction between monosaccharides exhibits an important role in the assembly of monosaccharide-containing molecules. In this work, three common monosaccharides, glucose, galactose and mannose, are employed to in... The interaction between monosaccharides exhibits an important role in the assembly of monosaccharide-containing molecules. In this work, three common monosaccharides, glucose, galactose and mannose, are employed to investigate the effect of monosaccharide on the self-assembly of benzenetricarboxamide(BTA) core-containing molecules. In the presence of monosaccharides, three benzenetricarboxamide derivatives aggregate into different ordered structures. When alanine linkers are introduced to these molecules between the core and the monosacchride, morphologies of three types of monosaccharide BTAs turned to disordered, meanwhile their structures become similar with the increase of the length of alanine linkers, indicating the disappearance of the monosaccharide effects. 展开更多
关键词 MONOSACCHARIDE SELF-ASSEMBLY Benzenetricarboxamide DYNAMIC LIGHT scatting (DLS) Depolarized DYNAMIC LIGHT scatting (DDLS)
One-dimensional dynamic compressive behavior of dry calcareous sand at high strain rates 预览
6
作者 Yaru Lv Jiagui Liu Ziming Xiong 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第1期192-201,共10页
Calcareous sand has distinct characteristics in comparison with silica sand,such as dynamic behavior at high strain rates(HSRs).This is closely related to pile driving,aircraft wheel loading and mining activities.To u... Calcareous sand has distinct characteristics in comparison with silica sand,such as dynamic behavior at high strain rates(HSRs).This is closely related to pile driving,aircraft wheel loading and mining activities.To understand the response of calcareous sand at HSRs,a series of dynamic tests is performed using the split Hopkinson pressure bar(SHPB)with steel sleeve,including 6 validation tests of bar-against-bar and 16 comparative tests relevant to the relative density and strain rate of calcareous and silica sands.The apparent dynamic stiffness of calcareous sand is approximately 10%of that for silica sand due to different particle shapes and mineral compositions.The axial stress-strain response of silica sand is mainly governed by the deformation of individual grain and soil skeleton,and particle crushing.However,porous calcareous sand shows yielding and strain-hardening responses that are always followed by particle crushing.As the applied loading increases,the particle crushing of calcareous sand develops from local instability to whole breakage.Calcareous sand has lower viscous flow effects compared with silica sand at HSRs. 展开更多
关键词 Split Hopkinson pressure bar(SHPB)test CALCAREOUS sand DYNAMIC behavior DYNAMIC STIFFNESS Particle CRUSHING
在线阅读 下载PDF
Study on Rigid-Flexible Coupling Effects of Floating Offshore Wind Turbines 预览
7
作者 CHEN Jia-hao HU Zhi-qiang +1 位作者 LIU Ge-liang WAN De-cheng 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第1期1-13,共13页
In order to account for rigid-flexible coupling effects of floating offshore wind turbines,a nonlinear rigid-flexible coupled dynamic model is proposed in this paper.The proposed nonlinear coupled model takes the high... In order to account for rigid-flexible coupling effects of floating offshore wind turbines,a nonlinear rigid-flexible coupled dynamic model is proposed in this paper.The proposed nonlinear coupled model takes the higher-order axial displacements into account,which are usually neglected in the conventional linear dynamic model.Subsequently,investigations on the dynamic differences between the proposed nonlinear dynamic model and the linear one are conducted.The results demonstrate that the stiffness of the turbine blades in the proposed nonlinear dynamic model increases with larger overall motions but that in the linear dynamic model declines with larger overall motions.Deformation of the blades in the nonlinear dynamic model is more reasonable than that in the linear model as well.Additionally,more distinct coupling effects are observed in the proposed nonlinear model than those in the linear model.Finally,it shows that the aerodynamic loads,the structural loads and global dynamic responses of floating offshore wind turbines using the nonlinear dynamic model are slightly smaller than those using the linear dynamic model.In summary,compared with the conventional linear dynamic model,the proposed nonlinear coupling dynamic model is a higher-order dynamic model in consideration of the rigid-flexible coupling effects of floating offshore wind turbines,and accord more perfectly with the engineering facts. 展开更多
关键词 FLOATING OFFSHORE WIND TURBINE DYNAMIC STIFFENING effect nonlinear coupled DYNAMIC model DARwind
在线阅读 下载PDF
Locomotion Stability Analysis of Lower Extremity Augmentation Device
8
作者 Likun Wang Chaofeng Chen +3 位作者 Wei Dong Zhijiang Du Yi Shen Guangyu Zhao 《仿生工程学报:英文版》 SCIE EI CSCD 2019年第1期99-114,共16页
Stability is of great significance in the theoretical framework of biped locomotion.Real-time control and walking patterns planning are on the premise that the robot works in the stable condition.In this paper,we addr... Stability is of great significance in the theoretical framework of biped locomotion.Real-time control and walking patterns planning are on the premise that the robot works in the stable condition.In this paper,we address the crucial issue of the locomotion stability based on the modified Poincare return map and the hybrid automata.Not akin to the traditional stability criteria,i.e.,the Zero Moment Point(ZMP)and the Center of Mass(CoM),the modified Poincare return map is more appropriate for both dynamic walking arid non-periodic walking.Moreover,a novel high-level reinforcement learning methodology,so-called active PI2 CMA-ES,is proposed in this paper to plan the exoskeleton locomotion.The proposed learning methodology demonstrates that the locomotion of the exoskeleton is asymptotically stable according to the modified Poincare return map criterion.Finally,the proposed learning methodology is tested by the Lower Extremity Augmentation Device(LEAD)and its effectiveness is verified by the experiments. 展开更多
关键词 BIPED locomotion DYNAMIC WALKING DYNAMIC Movement Primitives (DMP) stability EXOSKELETON bioinspiration
Low frequency vibration control of railway vehicles based on ahigh static low dynamic stiffness dynamic vibration absorber
9
作者 SUN Yu GONG Dao +2 位作者 ZHOU JinSong SUN WenJing XIA ZhangHui 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2019年第1期60-69,共10页
In order to control the low frequency vibration of railway vehicles, a vertical two degrees of freedom(2DOF) low frequency dynamic vibration absorber(DVA) based on acceleration is proposed. Parameters of the dynamic v... In order to control the low frequency vibration of railway vehicles, a vertical two degrees of freedom(2DOF) low frequency dynamic vibration absorber(DVA) based on acceleration is proposed. Parameters of the dynamic vibration absorber are put forth to control the low frequency vibration of car body bouncing and pitching. Next, the acceleration power spectrum density(PSD)and ride quality of the car body are calculated based on the pseudo excitation method(PEM) and covariance algorithm,respectively. According to the requirement of 2DOF low frequency DVA, the isolators with high static low dynamic stiffness(HSLDS) are designed. A high-speed train dynamic model containing HSLDS isolators is established to validate the effects on the car body vibration. The results reveal that the 2D low frequency DVA can significantly reduce the vibration of the car body bouncing and pitching. Thus, the ride quality of the vehicle is increased, and passenger comfort is improved. 展开更多
关键词 railway vehicle dynamics RIDE quality LOW frequency DYNAMIC vibration ABSORBER high STATIC LOW DYNAMIC STIFFNESS
Dynamic Performance Analysis of Steel Frame Structure under Seismic Action 预览
10
作者 Xiaojun Yuan Jinlong Liu +2 位作者 Yanmu Qu Kailin Wei Haifeng Zong 《建筑与工程前沿研究(英文)》 2019年第2期1-4,共4页
In order to find out the dynamic characteristics of a steel frame structure project in the 8 degree (0.3g) area, the artificial wave, Taft wave and El Centro wave were input by using the finite element analysis softwa... In order to find out the dynamic characteristics of a steel frame structure project in the 8 degree (0.3g) area, the artificial wave, Taft wave and El Centro wave were input by using the finite element analysis software ANSYS. The dynamic time-history analysis of the structure shows the dynamic performance of the structure under the frequent earthquakes and rare earthquakes. 展开更多
关键词 STEEL FRAME STRUCTURE DYNAMIC TIME-HISTORY ANALYSIS DYNAMIC performance
在线阅读 免费下载
Genetic programming for predictions of effectiveness of rolling dynamic compaction with dynamic cone penetrometer test results 预览
11
作者 R.A.T.M.Ranasinghe M.B.Jaksa +1 位作者 F.Pooya Nejad Y.L.Kuo 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第4期815-823,共9页
Rolling dynamic compaction (RDC),which employs non-circular module towed behind a tractor,is an innovative soil compaction method that has proven to be successful in many ground improvement applications.RDC involves r... Rolling dynamic compaction (RDC),which employs non-circular module towed behind a tractor,is an innovative soil compaction method that has proven to be successful in many ground improvement applications.RDC involves repeatedly delivering high-energy impact blows onto the ground surface,which improves soil density and thus soil strength and stiffness.However,there exists a lack of methods to predict the effectiveness of RDC in different ground conditions,which has become a major obstacle to its adoption.For this,in this context,a prediction model is developed based on linear genetic programming (LGP),which is one of the common approaches in application of artificial intelligence for nonlinear forecasting.The model is based on in situ density-related data in terms of dynamic cone penetrometer (DCP) results obtained from several projects that have employed the 4-sided,8-t impact roller (BH-1300).It is shown that the model is accurate and reliable over a range of soil types.Furthermore,a series of parametric studies confirms its robustness in generalizing data.In addition,the results of the comparative study indicate that the optimal LGP model has a better predictive performance than the existing artificial neural network (ANN) model developed earlier by the authors. 展开更多
关键词 Ground improvement ROLLING DYNAMIC compaction (RDC) Linear genetic programming (LGP) DYNAMIC cone PENETROMETER (DCP) test
在线阅读 下载PDF
Evaluation of tumor response to antiangiogenic therapy in patients with recurrent gliomas using contrast-enhanced perfusion-weighted magnetic resonance imaging techniques: A meta-analysis 预览
12
作者 Akanganyira Kasenene Aju Baidya +1 位作者 Salman Shams Hai-Bo Xu 《世界荟萃分析杂志》 2019年第2期51-65,共15页
BACKGROUND It is of vital importance to find radiologic biomarkers that can accurately predict treatment response. Usually, the initiation of antiangiogenic therapy causes a rapid decrease in the contrast enhancing tu... BACKGROUND It is of vital importance to find radiologic biomarkers that can accurately predict treatment response. Usually, the initiation of antiangiogenic therapy causes a rapid decrease in the contrast enhancing tumor. However, the treatment response is observed only in a fraction of patients due to the partial radiological response secondary to stabilization of abnormal vessels which does not essentially indicate a true antitumor effect. Perfusion-weighted magnetic resonance imaging (PWMRI) techniques have shown implicitness as a strong imaging biomarker for gliomas since they give hemodynamic information of blood vessels. Hence, there is a rapid expansion of PW-MRI related studies and clinical applications. AIM To determine the diagnostic performance of PW-MRI techniques including:(A) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI);and (B) dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) for evaluating response to antiangiogenic therapy in patients with recurrent gliomas. METHODS Databases such as PubMed (MEDLINE included), EMBASE, and Google Scholar were searched for relevant original articles. The included studies were assessed for methodological quality with the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Medical imaging follow-up or histopathological analysis was used as the reference standard. The data were extracted by two reviewers independently, and then the sensitivity, specificity, summary receiver operating characteristic curve, area under the curve (AUC), and heterogeneity were calculated using Meta-Disc 1.4 software.RESULTS This study analyzed a total of six articles. The overall sensitivity for DCE-MRI and DSC-MRI was 0.69 [95% confidence interval (CI): 0.53-0.82], and the specificity was 0.99 (95%CI: 0.93-1) by a random effects model (DerSimonianee- Laird model). The likelihood ratio (LR)+, LR-, and diagnostic odds ratio (DOR) were 12.84 (4.54-36.28), 0.35 (0.22-0.53), and 24.44 (7.19-83.06), respectively. The AUC (± SE) was 0.9921 (± 0.0120), 展开更多
关键词 Glioma Perfusion-weighted MAGNETIC RESONANCE IMAGING DYNAMIC contrastenhanced MAGNETIC RESONANCE IMAGING DYNAMIC susceptibility contrast MAGNETIC RESONANCE IMAGING Anti-vascular endothelial growth factor ANTIANGIOGENIC Metaanalysis
在线阅读 免费下载
Useful life prediction using a stochastic hybrid automata model for an ACS multi-gyro subsystem 预览
13
作者 CHENG Yuehua JIANG Liang +1 位作者 JIANG Bin LU Ningyun 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第1期154-166,共13页
A useful life prediction method based on the integration of the stochastic hybrid automata (SHA) model and the frame of the dynamic fault tree (DFT) is proposed. The SHA model can incorporate the orbit environment, wo... A useful life prediction method based on the integration of the stochastic hybrid automata (SHA) model and the frame of the dynamic fault tree (DFT) is proposed. The SHA model can incorporate the orbit environment, work modes, system configuration, dynamic probabilities and degeneration of components, as well as spacecraft dynamics and kinematics. By introducing the frame of DFT, the system is classified into several layers, and the problem of state combination explosion is artfully overcome. An improved dynamic reliability model (DRM) based on the Nelson hypothesis is investigated to improve the defect of cumulative failure probability (CFP), which is used to address the failure probability of components in the SHA model. The simulation using the Monte-Carlo method is finally conducted on two satellites, which are deployed with the same multi-gyro subsystem but run on different orbits. The results show that the predicted useful life of the attitude control system (ACS) with consideration of abrupt failure, degradation, and running environment is quite different between the two satellites. 展开更多
关键词 useful life prediction STOCHASTIC hybrid AUTOMATA (SHA) multi-gyro SUBSYSTEM DYNAMIC fault tree (DFT) DYNAMIC reliability.
在线阅读 下载PDF
Thermodynamic prediction and experimental investigation of short-term dynamic membrane formation in dynamic membrane bioreactors:Effects of sludge properties
14
作者 Zhenzhen Yu Yisong Hu +1 位作者 Mawuli Dzakpasu Xiaochang C.Wang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第3期85-96,共12页
In dynamic membrane bioreactors(DMBRs), a dynamic membrane(DM) forms on a support material to act as the separation membrane for solids and liquids. In this study, batch filtration tests were carried out in a DMBR usi... In dynamic membrane bioreactors(DMBRs), a dynamic membrane(DM) forms on a support material to act as the separation membrane for solids and liquids. In this study, batch filtration tests were carried out in a DMBR using nylon mesh(25 μm) as support material to filtrate sludge suspensions of variable properties from three different sources to evaluate the effects on the short-term DM formation process(within 240 min). Furthermore, the extended Derjaguin–Landau–Verwey–Overbeek(XDLVO) theory was applied to analyze the sludge adhesion and cohesion behaviors on the mesh surface to predict quantitative parameters of the short-term DM formation process(including initial formation and maturation stage). The filtration results showed that the order of the initial DM formation time(permeate turbidity <1 NTU as an indicator) was as follows: sludge with poor settleability and dewaterability < normal sludge <sludge with poor flocculability. Moreover, normal sludge(regarding settleability, dewaterability,flocculability, and extracellular polymeric substance) showed a more acceptable DM formation performance(short DM formation time, low permeate turbidity, and high permeate flux) than sludge with poor settleability, dewaterability and flocculability. The influence of sludge properties on the initial DM formation time corroborates the prediction of sludge adhesion behaviors by XDLVO theory. Additionally, the XDLVO calculation results showed that acid–based interaction, energy barrier, and secondary energy minimum were important determinants of the sludge adhesion and cohesion behaviors. Therefore, short-term DM formation process may be enhanced to achieve stable long-term DMBR operation through positive modification of the sludge properties. 展开更多
关键词 DYNAMIC MEMBRANE BIOREACTOR DYNAMIC MEMBRANE FORMATION XDLVO theory SLUDGE properties Wastewater treatment
Stability Analysis and Structural Parameters Optimization of Quadrotor Unmanned Aerial Vehicles 预览
15
作者 CHEN Cheng ZHANG Liru +2 位作者 ZHANG Cheng FU Weijie LIU Na 《国际设备工程与管理:英文版》 2019年第1期19-29,共11页
To increase dynamic stability of the quadrotor unmanned aerial vehicles in varying mechanical structure.The qualitative analysis is considered the main methods for analyzing the dynamic stability,while the index of qu... To increase dynamic stability of the quadrotor unmanned aerial vehicles in varying mechanical structure.The qualitative analysis is considered the main methods for analyzing the dynamic stability,while the index of qualitative analysis of the structural stability and the dynamic stability are still hard to establish.Therefore,the process during rolling or pitching is selected for investigating in the present papers,the method of Lyapunov exponent is adopted for establishing the quantification relationship of between structural parameters of quadrotor unmanned aerial vehicles and dynamic stability,and its dynamic stability for guiding the design of the vehicle′s mechanical structure and the optimization of its stability control by using the relationship.As compared to its counterpart of Lyapunov′s second method,the main advantage of the concept of Lyapunov exponents is that the methods for calculating the exponent process are constructive which makes the stability analysis of complex nonlinear systems possible. 展开更多
关键词 QUADROTOR unmanned AERIAL vehicles structure optimization DYNAMIC model DYNAMIC stability LYAPUNOV EXPONENT
在线阅读 免费下载
快餐巨擘还是科技领导者?麦当劳为何以3亿美元买下一家鲜为人知的新创公司
16
作者 Justin Bariso 陈信宏(译) 《空中英语教室:高级版.彭蒙惠英语》 2019年第9期6-7,38共3页
当劳宣布该公司二十年来最大的一项收购时,许多人都大为震惊。不,麦当劳没有买下竞争对手。而是买下了一家科技公司。没当劳达成协议,买下Dynamic Yield这家专精于“决策逻辑”科技的以色列新创公司。这家科技公司根据从用户先前购买行... 当劳宣布该公司二十年来最大的一项收购时,许多人都大为震惊。不,麦当劳没有买下竞争对手。而是买下了一家科技公司。没当劳达成协议,买下Dynamic Yield这家专精于“决策逻辑”科技的以色列新创公司。这家科技公司根据从用户先前购买行为中获取的信息,借此推荐额外的购买选项。 展开更多
关键词 麦当劳 科技 领导者 DYNAMIC 快餐 竞争对手 决策逻辑 购买行为
当油遇上电,有几种可能性?广汽本田雅阁锐·混动VS广汽丰田凯美瑞双擎
17
作者 陈家诚 《汽车杂志》 2019年第1期10012-10017,共6页
两位都是占据市场半壁江山的大神,甚至可以说这个价位带新能源动力车基本就是它们的山头……如果把两位放在一起"神仙打架",会打出怎么样的故事?性能之战:城市、高速各擅胜场雅阁锐·混动的第三代i-MMD和凯美瑞双擎的THS... 两位都是占据市场半壁江山的大神,甚至可以说这个价位带新能源动力车基本就是它们的山头……如果把两位放在一起"神仙打架",会打出怎么样的故事?性能之战:城市、高速各擅胜场雅阁锐·混动的第三代i-MMD和凯美瑞双擎的THSⅡ都是新一代轻混系统,相对而言凯美瑞双擎相对上一代产品的改进更大,尤其是更换了全新热效率高达41%的2.5L Dynamic Force发动机以及全新的E-CVT变速机构。 展开更多
关键词 本田雅阁 凯美瑞 Dynamic 丰田 THSⅡ 变速机构 动力车 新能源
Online scheduling of image satellites based on neural networks and deep reinforcement learning
18
作者 Haijiao WANG Zhen YANG +1 位作者 Wugen ZHOU Dalin LI 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第4期1011-1019,共9页
In the ‘‘Internet Plus' era, space-based information services require effective and fast image satellite scheduling. Most existing studies consider image satellite scheduling to be an optimization problem to sol... In the ‘‘Internet Plus' era, space-based information services require effective and fast image satellite scheduling. Most existing studies consider image satellite scheduling to be an optimization problem to solve with searching algorithms in a batch-wise manner. No real-time speed method for satellite scheduling exists. In this paper, with the idea of building a real-time speed method, satellite scheduling is remodeled based on a Dynamic and Stochastic Knapsack Problem(DSKP), and the objective is to maximize the total expected profit. No existing algorithm could be able to solve this novel scheduling problem properly. With inspiration from the recent achievements in Deep Reinforcement Learning(DRL) in video games, AlphaGo and dynamic controlling,a novel DRL-based method is applied to training a neural network to schedule tasks. The numerical results show that the method proposed in this paper can achieve relatively good performance with real-time speed and immediate respond style. 展开更多
关键词 DEEP REINFORCEMENT learning Dynamic SCHEDULING IMAGE SATELLITES Neural network Online SCHEDULING
Dynamic Measurement of Task Scheduling Algorithm in Multi-Processor System
19
作者 谢盈 吴尽昭 +1 位作者 陈建英 崔梦天 《上海交通大学学报:英文版》 EI 2019年第3期372-380,共9页
It is important to evaluate function behaviors and performance features of task scheduling algorithm in the multi-processor system.A novel dynamic measurement method(DMM)was proposed to measure the task scheduling alg... It is important to evaluate function behaviors and performance features of task scheduling algorithm in the multi-processor system.A novel dynamic measurement method(DMM)was proposed to measure the task scheduling algorithm's correctness and dependability.In a multi-processor system,task scheduling problem is represented by a combinatorial evaluation model,interactive Markov chain(IMC),and solution space of the algorithm with time and probability metrics is described by action-based continuous stochastic logic(aCSL).DMM derives a path by logging runtime scheduling actions and corresponding times.Through judging whether the derived path can be received by task scheduling IMC model,DMM analyses the correctness of algorithm.Through judging whe ther the actual values satisfy label function of the initial st ate,DMM analyses the dependability of algorthm.The simulation shows that DMM can effectively characterize the function behaviors and performance features of task scheduling algorithm. 展开更多
关键词 MULTI-PROCESSOR TASK SCHEDULING algorithm IMC aCSL DYNAMIC measurement
Energy Separation and Explicit Dynamic Analysis of Low Temperature Impact Toughness of Transmission Tower Material Q420B
20
作者 余兴学 张映华 +1 位作者 张晓敏 蒋渝 《上海交通大学学报:英文版》 EI 2019年第3期381-387,共7页
To determine the physical significance of the impact toughness parameters and accurately characterize the low temperature impact toughness of transmission tower material Q420 B,the finite element model of Charpy impac... To determine the physical significance of the impact toughness parameters and accurately characterize the low temperature impact toughness of transmission tower material Q420 B,the finite element model of Charpy impact test is established on the basis of experiment.The simulation and test results are verified,and the specimen fracture is analyzed by scanning electron microscope.The formation and growth mechanism of the crack are dynamically analyzed.On this basis,energy separation method is used to investigate the effect of low temperature on impact toughness.The results show that the simulation and test results are in good agreement,and the ductile-brittle transition temperature of Q420 B is about-50 ℃.The breaking process of the specimen is divided into the crack formation and propagation.When temperature drops from 20 to-60 ℃,the crack propagation energy decreases from 51.0 to 11.9 J,the crack formation energy reduces from 39.9 to 15.8 J,and the fracture time of the material drops from 1.8 to 0.6 ms. 展开更多
关键词 Q420B LOW temperature impact TOUGHNESS simulation EXPLICIT dynamic ENERGY SEPARATION
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈