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fraction induced by interaction burning of tri-symmetric propane fires in open space based on weighted multi-point

Jie JI, Junrui DUAN, Huaxian WAN

《能源前沿(英文)》 2022年 第16卷 第6期   页码 1017-1026 doi: 10.1007/s11708-020-0716-x

摘要: The interaction of multiple fires may lead to a higher flame height and more intense radiation flux than a single fire, which increases the possibility of flame spread and risks to the surroundings. Experiments were conducted using three burners with identical heat release rates (HRRs) and propane as the fuel at various spacings. The results show that flames change from non-merging to merging as the spacing decreases, which result in a complex evolution of flame height and merging point height. To facilitate the analysis, a novel merging criterion based on the dimensionless spacing / was proposed. For non-merging flames ( / >0.368), the flame height is almost identical to a single fire; for merging flames ( / ≤0.368), based on the relationship between thermal buoyancy and thrust (the pressure difference between the inside and outside of the flame), a quantitative analysis of the flame height, merging point height, and air entrainment was formed, and the calculated merging flame heights show a good agreement with the measured experimental values. Moreover, the multi-point source model was further improved, and radiation fraction of propane was calculated. The data obtained in this study would play an important role in calculating the external radiation of propane fire.

关键词: flame interaction     air entrainment     flame height     multi-point source model     thermal radiation    

Optimization of controlled mechanism based on generalized inverse method

YANG Jin-tang, KONG Jian-yi, XIONG He-gen, JIANG Guo-zhang, LI Gong-fa

《机械工程前沿(英文)》 2006年 第1卷 第3期   页码 288-291 doi: 10.1007/s11465-006-0037-8

摘要: Based on the mechanical features of the controlled driving component and the characteristics of controlled mechanism of two degrees of freedom, a circle fitting optimization model of controlled mechanism that accurately realizes the multi-point track, has been established. The generalized inverse method for solving compensation movement displacement has been presented.

关键词: controlled     displacement     multi-point     compensation     optimization    

Fundamental frequency and testing mode of complicated elastic clamped-plate vibration

QI Hongyuan, GUAN Yiduo

《机械工程前沿(英文)》 2008年 第3卷 第4期   页码 360-364 doi: 10.1007/s11465-008-0084-4

摘要: Aimed at the modal analysis of complicated elastic clamped-plates, a trigonometric interpolation method of conformal mapping is applied to set up the mapping function between a complicated region and a unit dish region, and the fundamental frequency of the complicated vibrating region is analyzed with the help of the Galerkin method. Taking an elastic rectangle-plate with arc radius as an example, the testing mode frequency band of plates is determined by analyzing the fundamental frequency; meanwhile, according to hamming testing method of multi-point excitation to the single-point response, and by signal processing technology and its software programming, modal parameter recognition of the elastic clamped-plate is completed. Comparing the first order modal frequency with the theoretical fundament frequency, the validity of the testing mode method and theoretical analysis are verified.

关键词: multi-point excitation     rectangle-plate     single-point     processing technology     trigonometric interpolation    

A multiscale-contour-based interpolation framework for generating a time-varying quasi-dense point cloud

Chu-hua HUANG,Dong-ming LU,Chang-yu DIAO

《信息与电子工程前沿(英文)》 2016年 第17卷 第5期   页码 422-434 doi: 10.1631/FITEE.1500316

摘要: To speed up the reconstruction of 3D dynamic scenes in an ordinary hardware platform, we propose an efficient framework to reconstruct 3D dynamic objects using a multiscale-contour-based interpolation from multi-view videos. Our framework takes full advantage of spatio-temporal-contour consistency. It exploits the property to interpolate single contours, two neighboring contours which belong to the same model, and two contours which belong to the same view at different times, corresponding to point-, contour-, and model-level interpolations, respectively. The framework formulates the interpolation of two models as point cloud transport rather than non-rigid surface deformation. Our framework speeds up the reconstruction of a dynamic scene while improving the accuracy of point-pairing which is used to perform the interpolation. We obtain a higher frame rate, spatio-temporal-coherence, and a quasi-dense point cloud sequence with color information. Experiments with real data were conducted to test the efficiency of the framework.

关键词: Multi-view video     Free-viewpoint video     Point-pair     Multiscale-contour-based interpolation     Spatio-temporal-contour     Consistency     Time-varying point cloud sequence    

Solving multi-objective optimal power flow problem considering wind-STATCOM using differential evolution

Belkacem MAHDAD, K. SRAIRI

《能源前沿(英文)》 2013年 第7卷 第1期   页码 75-89 doi: 10.1007/s11708-012-0222-x

摘要: In this paper, a simple strategy based differential evolution was proposed for solving the problem of multi-objective environmental optimal power flow considering a hybrid model (Wind-Shunt-FACTS). The DE algorithm optimized simultaneously a combined vector control based active power of wind sources and reactive power of multi STATCOM exchanged with the electrical power system to minimize fuel cost and emissions. The proposed strategy was examined and applied to the standard IEEE 30-bus with smooth cost function to solve the problem of security environmental economic dispatch considering multi distributed hybrid model based wind and STATCOM controllers. In addition, the proposed approach was validated on a large practical electrical power system 40 generating units considering valve point effect. Simulation results demonstrate that choosing the installation of multi type of FACTS devices in coordination with many distributed wind sources is a vital research area.

关键词: differential evolution     multi-objective function     optimal power flow     economic dispatch     valve point effect     environment     wind source     STATCOM    

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

《农业科学与工程前沿(英文)》 2023年 第10卷 第4期   页码 503-509 doi: 10.15302/J-FASE-2023528

摘要:

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

关键词: GREEN     AGRICULTURAL     PROMOTE     POLLUTION     SOURCE     DEVELOPMENT     POINT     STRENGTHENING     CONTROL    

基于多目标粒子群协同算法的状态参数优化

丁雷,吴敏,佘锦华,段平

《中国工程科学》 2010年 第12卷 第2期   页码 101-107

摘要:

针对铅锌烧结过程综合透气性、烧结终点的优化具有强非线性、计算复杂等特点,提出了一种有效的多目标粒子群协同优化算法。首先,建立了有综合透气性、烧结终点两个目标的优化模型。接着,通过改进的约束比较方法、粒子极值选取方法,以及利用不同的粒子群来分别优化相应的变量,提出了一种改进的多目标粒子群协同优化算法。最后,利用提出的多目标优化算法进行综合透气性、烧结终点的优化。仿真结果表明,所提出的多目标优化算法能较好地解决综合透气性、烧结终点的优化问题。

关键词: 铅锌烧结过程     综合透气性     烧结终点     多目标粒子群协同优化算法    

基于迁移学习与多视角感兴趣点的膝关节运动追踪网络 Article

王聪, 谢帅宁, 李康, 王重阳, 刘旭东, 赵亮, 蔡宗远

《工程(英文)》 2021年 第7卷 第6期   页码 881-888 doi: 10.1016/j.eng.2020.03.016

摘要:

近年来,深度学习为一种基于二维(2D)—三维(3D)配准技术以测量人体膝关节运动的方法,该方法提供了快速完成配准并增加捕捉范围的可能性。但这类方法受限于大量的数据需求,因此,我们提出了一种基于特征的迁移学习法,用于提取荧光透视影像的特征。通过三个受试者以及不到100对荧光透视影像,我们获得了40%的平均配准成功率。本研究提出的基于学习的配准方法,可在荧光透视影像数量有限时使用。

关键词: 2D—3D配准     机器学习     领域自适应     点对应    

光刻机小型复合节流静压气浮导轨微结构参数设计 Article

温众普,  吴剑威,  邢坤鹏,  张银,  李结安,  谭久彬

《工程(英文)》 2021年 第7卷 第2期   页码 226-237 doi: 10.1016/j.eng.2019.09.012

摘要:

在光刻机可变狭缝系统(VS)中,紧凑型复合节流静压气浮导轨是实现高精度、高加速度运动的首选结构。研究表明,导轨气浮工作面上加工浅腔、凹槽等微结构可以改善负载性能。然而,微结构微米级变化对导轨性能的影响尚不清晰。文中采用作者提出的网格自适应法,定量研究了微结构四个参数的影响,揭示了微结构变化对导轨负载性能的影响规律,并利用这些规律对微结构参数进行设计。设计方法的特点在于:通过调节浅腔参数,使承载力、刚度和转动刚度的工作点都统一起来。采用文中的设计流程和调整方法,可以在一定程度上缓解供气压力的限制和各项负载性能间的相互制约。实验结果表明,采用该方法所设计导轨的转动刚度达到2.14 × 104 Nm·rad–1,提高了69.8%。在ArF光刻机上的VS上对气浮导轨进行加速扫描实验,平均扫描加速度达到67.5 m·s–2
达到了设计要求。

关键词: 光刻机     复合节流静压气浮导轨     微结构     工作点     转动刚度    

Trajectory planning of mobile robots using indirect solution of optimal control method in generalized point-to-point

M. NAZEMIZADEH, H. N. RAHIMI, K. AMINI KHOIY

《机械工程前沿(英文)》 2012年 第7卷 第1期   页码 23-28 doi: 10.1007/s11465-012-0304-9

摘要:

This paper presents an optimal control strategy for optimal trajectory planning of mobile robots by considering nonlinear dynamic model and nonholonomic constraints of the system. The nonholonomic constraints of the system are introduced by a nonintegrable set of differential equations which represent kinematic restriction on the motion. The Lagrange’s principle is employed to derive the nonlinear equations of the system. Then, the optimal path planning of the mobile robot is formulated as an optimal control problem. To set up the problem, the nonlinear equations of the system are assumed as constraints, and a minimum energy objective function is defined. To solve the problem, an indirect solution of the optimal control method is employed, and conditions of the optimality derived as a set of coupled nonlinear differential equations. The optimality equations are solved numerically, and various simulations are performed for a nonholonomic mobile robot to illustrate effectiveness of the proposed method.

关键词: mobile robot     trajectory planning     nonlinear dynamic     optimal control    

Toward autonomous mining: design and development of an unmanned electric shovel via point cloud-based

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0686-2

摘要: With the proposal of intelligent mines, unmanned mining has become a research hotspot in recent years. In the field of autonomous excavation, environmental perception and excavation trajectory planning are two key issues because they have considerable influences on operation performance. In this study, an unmanned electric shovel (UES) is developed, and key robotization processes consisting of environment modeling and optimal excavation trajectory planning are presented. Initially, the point cloud of the material surface is collected and reconstructed by polynomial response surface (PRS) method. Then, by establishing the dynamical model of the UES, a point to point (PTP) excavation trajectory planning method is developed to improve both the mining efficiency and fill factor and to reduce the energy consumption. Based on optimal trajectory command, the UES performs autonomous excavation. The experimental results show that the proposed surface reconstruction method can accurately represent the material surface. On the basis of reconstructed surface, the PTP trajectory planning method rapidly obtains a reasonable mining trajectory with high fill factor and mining efficiency. Compared with the common excavation trajectory planning approaches, the proposed method tends to be more capable in terms of mining time and energy consumption, ensuring high-performance excavation of the UES in practical mining environment.

关键词: autonomous excavation     unmanned electric shovel     point cloud     excavation trajectory planning    

Room temperature liquid metal: its melting point, dominating mechanism and applications

Junheng FU, Chenglin ZHANG, Tianying LIU, Jing LIU

《能源前沿(英文)》 2020年 第14卷 第1期   页码 81-104 doi: 10.1007/s11708-019-0653-8

摘要: The room temperature liquid metal (LM) is recently emerging as a new class of versatile materials with fascinating characteristics mostly originated from its simultaneous metallic and liquid natures. The melting point is a typical parameter to describe the peculiarity of LM, and a pivotal factor to consider concerning its practical applications such as phase change materials (PCMs) and advanced thermal management. Therefore, the theoretical exploration into the melting point of LM is an essential issue, which can be of special value for the design of new LM materials with desired properties. So far, some available strategies such as molecular dynamics (MD) simulation and classical thermodynamic theory have been applied to perform correlative analysis. This paper is primarily dedicated to performing a comprehensive overview regarding typical theoretical strategies on analyzing the melting points. It, then, presents evaluations on several factors like components, pressure, size and supercooling that may be critical for melting processes of liquid metal. After that, it discusses applications associated with the characteristic of low melting points of LM. It is expected that a great many fundamental and practical works are to be conducted in the coming future.

关键词: melting point     liquid metal     crystal     thermodynamics     molecular dynamics    

DITCHES AND PONDS CAN BE THE SOURCES OR SINKS OF NON-POINT SOURCE POLLUTION: OBSERVATIONS IN AN UPLAND

《农业科学与工程前沿(英文)》 2023年 第10卷 第4期   页码 607-626 doi: 10.15302/J-FASE-2023517

摘要:

As the common features of agroecosystems, ditches and ponds benefit the irrigation and drainage, as well as intercepting non-point source pollutants. However, most ditch-pond studies have been conducted in lowland areas. To test this source-sink assumption in upland areas, this study made observations on the ecological function of the ditch and pond system in a typical catchment in China. First, the changes in ponds in the catchment were analyzed using high-resolution remote sensing data. Then, the migration of agricultural pollutants in ditches and ponds were analyzed by field sampling and laboratory detection. The results showed that over the past 15 years the length of ditches in the catchment and the number of small ponds (< 500 m2) have increased by 32% and 75%, respectively. The rate of change in nutrient concentrations in the ditches and ponds were mostly from −20% to 20%, indicating ditches and ponds can be both sources and sinks for agricultural pollutants. Lastly, the contributing factors were explored and it was found that ditches and ponds are important sinks in dry season. However, during the rainy season, ditches and ponds become sources of pollutants, with the rapid drainage of ditches and the overflow of ponds in upland areas. The results of this study revealed that the ditches and ponds could be used for ecological engineering in upland catchments to balance drainage and intercept pollutants.

关键词: ditches     ponds     non-point source pollution     mountainous areas     nitrogen     phosphorus    

Schedule refinement for homogeneousmulti-core processors in the presence of manufacturing-caused heterogeneity

Zhi-xiang CHEN,Zhao-lin LI,Shan CAO,Fang WANG,Jie ZHOU

《信息与电子工程前沿(英文)》 2015年 第16卷 第12期   页码 1018-1033 doi: 10.1631/FITEE.1500035

摘要: Multi-core homogeneous processors have been widely used to deal with computation-intensive embedded applications. However, with the continuous down scaling of CMOS technology, within-die variations in the manufacturing process lead to a significant spread in the operating speeds of cores within homogeneous multi-core processors. Task scheduling approaches, which do not consider such heterogeneity caused by within-die variations, can lead to an overly pessimistic result in terms of performance. To realize an optimal performance according to the actual maximum clock frequencies at which cores can run, we present a heterogeneity-aware schedule refining (HASR) scheme by fully exploiting the heterogeneities of homogeneous multi-core processors in embedded domains. We analyze and show how the actual maximum frequencies of cores are used to guide the scheduling. In the scheme, representative chip operating points are selected and the corresponding optimal schedules are generated as candidate schedules. During the booting of each chip, according to the actual maximum clock frequencies of cores, one of the candidate schedules is bound to the chip to maximize the performance. A set of applications are designed to evaluate the proposed scheme. Experimental results show that the proposed scheme can improve the performance by an average value of 22.2%, compared with the baseline schedule based on the worst case timing analysis. Compared with the conventional task scheduling approach based on the actual maximum clock frequencies, the proposed scheme also improves the performance by up to 12%.

关键词: Schedule refining     Multi-core processor     Heterogeneity     Representative chip operating point    

Ceramic water filter for point-of-use water treatment in developing countries: Principles, challenges

Haiyan Yang, Shangping Xu, Derek E. Chitwood, Yin Wang

《环境科学与工程前沿(英文)》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1254-9

摘要: • CWF is a sustainable POU water treatment method for developing areas. • CWF manufacturing process is critical for its filtration performance. • Simultaneous increase of flow rate and pathogen removal is a challenge. • Control of pore size distribution holds promises to improve CWF efficiency. • Novel coatings of CWFs are a promising method to improve contaminant removal. Drinking water source contamination poses a great threat to human health in developing countries. Point-of-use (POU) water treatment techniques, which improve drinking water quality at the household level, offer an affordable and convenient way to obtain safe drinking water and thus can reduce the outbreaks of waterborne diseases. Ceramic water filters (CWFs), fabricated from locally sourced materials and manufactured by local labor, are one of the most socially acceptable POU water treatment technologies because of their effectiveness, low-cost and ease of use. This review concisely summarizes the critical factors that influence the performance of CWFs, including (1) CWF manufacturing process (raw material selection, firing process, silver impregnation), and (2) source water quality. Then, an in-depth discussion is presented with emphasis on key research efforts to address two major challenges of conventional CWFs, including (1) simultaneous increase of filter flow rate and bacterial removal efficiency, and (2) removal of various concerning pollutants, such as viruses and metal(loid)s. To promote the application of CWFs, future research directions can focus on: (1) investigation of pore size distribution and pore structure to achieve higher flow rates and effective pathogen removal by elucidating pathogen transport in porous ceramic and adjusting manufacture parameters; and (2) exploration of new surface modification approaches with enhanced interaction between a variety of contaminants and ceramic surfaces.

关键词: Point-of-use water treatment     Ceramic water filter     Bacterial removal     Surface modification     Water quality    

标题 作者 时间 类型 操作

fraction induced by interaction burning of tri-symmetric propane fires in open space based on weighted multi-point

Jie JI, Junrui DUAN, Huaxian WAN

期刊论文

Optimization of controlled mechanism based on generalized inverse method

YANG Jin-tang, KONG Jian-yi, XIONG He-gen, JIANG Guo-zhang, LI Gong-fa

期刊论文

Fundamental frequency and testing mode of complicated elastic clamped-plate vibration

QI Hongyuan, GUAN Yiduo

期刊论文

A multiscale-contour-based interpolation framework for generating a time-varying quasi-dense point cloud

Chu-hua HUANG,Dong-ming LU,Chang-yu DIAO

期刊论文

Solving multi-objective optimal power flow problem considering wind-STATCOM using differential evolution

Belkacem MAHDAD, K. SRAIRI

期刊论文

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

期刊论文

基于多目标粒子群协同算法的状态参数优化

丁雷,吴敏,佘锦华,段平

期刊论文

基于迁移学习与多视角感兴趣点的膝关节运动追踪网络

王聪, 谢帅宁, 李康, 王重阳, 刘旭东, 赵亮, 蔡宗远

期刊论文

光刻机小型复合节流静压气浮导轨微结构参数设计

温众普,  吴剑威,  邢坤鹏,  张银,  李结安,  谭久彬

期刊论文

Trajectory planning of mobile robots using indirect solution of optimal control method in generalized point-to-point

M. NAZEMIZADEH, H. N. RAHIMI, K. AMINI KHOIY

期刊论文

Toward autonomous mining: design and development of an unmanned electric shovel via point cloud-based

期刊论文

Room temperature liquid metal: its melting point, dominating mechanism and applications

Junheng FU, Chenglin ZHANG, Tianying LIU, Jing LIU

期刊论文

DITCHES AND PONDS CAN BE THE SOURCES OR SINKS OF NON-POINT SOURCE POLLUTION: OBSERVATIONS IN AN UPLAND

期刊论文

Schedule refinement for homogeneousmulti-core processors in the presence of manufacturing-caused heterogeneity

Zhi-xiang CHEN,Zhao-lin LI,Shan CAO,Fang WANG,Jie ZHOU

期刊论文

Ceramic water filter for point-of-use water treatment in developing countries: Principles, challenges

Haiyan Yang, Shangping Xu, Derek E. Chitwood, Yin Wang

期刊论文