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Numerical Simulations of Wave Impact Forces on the Open-Type Sea Access Road Using A Two-Phase SPH Model

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China Ocean Engineering 2024年第5期38卷 755-770页

作者： CHEN yong-kun Domenico D.MERINGOLO liu yong Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of ChinaQingdao 266100China Dipartimento D.I.C.E.A.M. Universitàdegli Studi Mediterranea di Reggio CalabriaVia Salita Melissari89124Reggio CalabriaItaly

A numerical study based on a two-dimensional two-phase SPH(Smoothed Particle Hydrodynamics)model to analyze the action of water waves on open-type sea access roads is *** study is a continuation of the analyses presented by Chen et al.(2022),in which the sea access roads are *** this new configuration,the sea access roads are placed above the still water level,therefore the presence of the air phase becomes a relevant issue in the determination of the wave forces acting on the ***,the comparison of wave forces on the open-type sea access roads obtained from the single and two-phase SPH models with the experimental results shows that the latter are in much better *** in the numerical simulations,a two-phaseδ-SPH model is adopted to investigate the dynamical *** on the numerical results,the maximum horizontal and uplifting wave forces acting on the sea access roads are analyzed by considering different wave conditions and geometries of the *** particular,the presence of the girder is analyzed and the differences in the wave forces due to the air cushion effects which are created below the structure are highlighted.

关键词： Smoothed Particle Hydrodynamics two-phase SPH wave impact forces experimental test sea access road

Regional Financial Development and Regional Economic Growth: An Empirical Analysis of Suzhou City, China

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Chinese Geographical Science 2010年第3期20卷 269-274页

作者： liu yong LI Weiping Economics School Peking University Beijing 100871 China China Development Bank Beijing 100037 China

There are many defects in researches on the relationship of the regional financial development (FD) and economic growth of China, such as simply assuming the causality direction, not highlighting financial institution, using incomplete financial indicator, etc. This article, taking Suzhou City of Jiangsu Province, China as a case, builds a simple model to study the level of FD from three aspects of financial scale, structure and institution. Three original indicators of PRIVY (private investment/aggregate investment), DEPTH (aggregate loan/GDP) and FDIVG (FDI/GDP) are used to construct the FD economic indicator through Principal Component Analysis approach. Then we use Granger method to analyze the relationship between the FD and the economic growth of Suzhou. Empirical test results show that the FD of Suzhou is the Granger reason of economic growth, while economic growth is not the reason for FD, because the relationship between the FD and the economic growth of Suzhou is just in the ″supply-leading″ period. In terms of Suzhou experiences, the local government should strengthen the protection of private investment, improve the institutional environment, and establish the reasonable financial structure. So we can concluded that FD could play a great role in promoting economic growth at the economy takeoff stage.

关键词： financial development regional economic growth institution Granger Causality Analysis

Kernel selection with spectral perturbation stability of kernel matrix

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Science China(Information Sciences) 2014年第11期57卷 47-56页

作者： liu yong LIAO ShiZhong School of Computer Science and Technology Tianjin University

Kernel selection is one of the key issues both in recent research and application of kernel *** is usually done by minimizing either an estimate of generalization error or some other related performance measure. Use of notions of stability to estimate the generalization error has attracted much attention in recent years. Unfortunately, the existing notions of stability, proposed to derive the theoretical generalization error bounds, are difficult to be used for kernel selection in practice. It is well known that the kernel matrix contains most of the information needed by kernel methods, and the eigenvalues play an important role in the kernel matrix. Therefore, we aim at introducing a new notion of stability, called the spectral perturbation stability,to study the kernel selection problem. This proposed stability quantifies the spectral perturbation of the kernel matrix with respect to the changes in the training set. We establish the connection between the spectral perturbation stability and the generalization error. By minimizing the derived generalization error bound, we propose a new kernel selection criterion that can guarantee good generalization properties. In our criterion,the perturbation of the eigenvalues of the kernel matrix is efficiently computed by solving the derivative of a newly defined generalized kernel matrix. Both theoretical analysis and experimental results demonstrate that our criterion is sound and effective.

关键词： kernel methods kernel selection stability spectral perturbation stability generalization error bound

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风筛组合式花生秧粉碎除膜机设计与试验

农机化研究 2025年第2期47卷 159-164页

作者：刘勇郑孟坤赵福勇王家胜青岛农业大学机电工程学院山东青岛266109 日照市勇杰农业装备有限公司山东日照263318

针对覆膜种植的花生收获后的地膜残留于饲料用花生秧严重影响牲畜健康的问题,结合粉碎后的花生秧与地膜的物理特性,设计了一种花生秧粉碎除膜机,可一次完成喂料粉碎、筛分输送、负压除膜、回料输送、出料收集等功能。对整机的关键部件... 详细信息

针对覆膜种植的花生收获后的地膜残留于饲料用花生秧严重影响牲畜健康的问题,结合粉碎后的花生秧与地膜的物理特性,设计了一种花生秧粉碎除膜机,可一次完成喂料粉碎、筛分输送、负压除膜、回料输送、出料收集等功能。对整机的关键部件进行了设计与分析,重点确定了粉碎装置、风筛式清选装置等部件的结构与工作参数。利用Design-Expert进行了试验设计,研究了振动筛频率、风机转速对花生秧残膜清选质量的影响,并对花生秧粉碎除膜机的工作参数进行了优化。试验结果表明:振动筛频率、风机转速对除膜率和损失率影响显著;当最优参数振动筛频率3.4 Hz、1号风机转速1000 r/min、2号风机转速1350 r/min、3号风机转速1500 r/min时,花生秧粉碎除膜机除膜率为96.8%,损失率为11.2%,实现花生秧中残膜的清选。

关键词：花生秧除膜风筛式

Indium tin oxide nanosized composite powder prepared using waste ITO target

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Rare Metals 2005年第3期24卷 277-282页

作者： liu Jiaxiang GAN yong ZENG Shengnan The Key Laboratory for Science and Technology of Controllable Chemical Reactions Ministry of Education College of Materials Science andEngineering Beijing University of Chemical Technology Beijing 100029 China

Indium tin oxide （ITO） nano-particles were prepared directly using waste ITO target, which had been coated by magnetron controlled sputtering. The waste ITO target was cleaned with de-ionized water, and then dissolved in acid, filtrated, neutralized, manipulated through azeotropic distillation and finally dried, and in this way the precursor of indium tin hydroxide was obtained. The nanosized rio composite powder was prepared after the precursor heat-treated at 500℃ for 2 h. TEM images show a narrow distribution of particle size is 5-20 nm and the particle size can be controlled. Its granule has a spherical shape and the dispersion of the particle is well. X-ray diffraction （XRD） patterns indicate the only cubic In2O3 phase in the ITO powder hot-treated at 500℃. The purity of ITO composite powder is 99.9907%. The content of radium within filtrate was detected by using the EDTA titration of determination of indium in the ITO powder and ITO target. Appropriate amount of SnCl4.5H2O was dissolved in the filtrate, and then ITO powder containing 10 wt.% SnO2 was successfully prepared by heat-treating.

关键词： waste ITO target nanosized ITO composite powder chemical technique microstructure

Extracting viewer interests for automated bookmarking in video-on-demand services

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Frontiers of Computer Science 2015年第3期9卷 415-430页

作者： Yang ZHAO Ye TIAN yong liu University of Science and Technology of China Hefei 230027 China Polytechnic Institute of New York University Brooklyn 11201 USA

Video-on-demand （VoD） services have become popular on the Internet in recent years. In VoD, it is challeng- ing to support the VCR functionality, especially the jumps, while maintaining a smooth streaming quality. Previous stud- ies propose to solve this problem by predicting the jump tar- get locations and prefetching the contents. However, through our analysis on traces from a real-world VoD service, we find that it would be fundamentally difficult to improve a viewer＇s VCR experience by simply predicting his future jumps, while ignoring the intentions behind these jumps. Instead of the prediction-based approach, in this paper, we seek to support the VCR functionality by bookmark- ing the videos. There are two key techniques in our pro- posed methodology. First, we infer and differentiate view- ers＇ intentions in VCR jumps by decomposing the inter- seek times, using an expectation-maximization （EM） algo- rithm, and combine the decomposed inter-seek times with the VCR jumps to compute a numerical interest score for each video segment. Second, based on the interest scores, we pro- pose an automated video bookrnarking algorithm. The algo- rithm employs the time-series change detection techniques of CUSUM and MB-GT, and bookmarks videos by detecting the abrupt changes on their interest score sequences. We evaluate our proposed techniques using real-world VoD traces from dozens of videos. Experimental results suggest that with our methods, viewers＇ interests within a video can be precisely extracted, and we can position bookmarks on the video＇shighlight events accurately. Our proposed video bookmark- ing methodology does not require any knowledge on video type, contents, and semantics, and can be applied on various types of videos.

关键词： video-on-demand (VoD) highlight bookmark-ing time-series change detection

Ranking grey numbers based on dominance grey degrees

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Journal of Systems Engineering and Electronics 2014年第4期25卷 618-626页

作者： yong liu Jeffrey Forrest Naiming Xie College of Economics and Management Nanjing University of Aeronautics and Astronautics School of Business Jiangnan University Mathematics Department Slippery Rock University of USA

With respect to the decision making problems where a lot of fuzzy and grey information always exists in the real-life decision making information system methods as fuzzy mathematics, it is difficult for such uncertainty probability, and interval numbers to deal with. To this end, based on the thought and method of grey numbers, grey degrees and interval numbers, the concept of dominance grey degree is defined. And then a method of ranking interval grey numbers based on the dominance grey degree is proposed. After discussing the relevant properties, the paper finally uses an example to demonstrate the effectiveness and applicability of the model. The result shows that the proposed model can more accurately describe uncertainty decision making problems, and realize the total ordering process for multiple-attribute decision-making problems.

关键词： grey information dominance grey degree intervalgrey number total ordering.

Flow Field Characteristics for Parachute-projectile System

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Chinese Journal of Mechanical Engineering 2011年第5期24卷 813-819页

作者： ZHU yong liu Li WANG Zhengping School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 China

In the current research for parachute flow field nowadays,the size of parachutes in previous research are so large compared with their carriers that the effects of the carriers wake flow to parachute are always *** from such large parachutes,the parachute size in this paper is on the same magnitude with the carrier,thus,the carrier can obviously affect the parachute flow *** this paper,flow field characteristics of small parachute for projectile decelerating are researched through two approaches,namely,computational fluid dynamics（CFD） simulation and wind tunnel *** parachutes with various sizes are chosen for ***,the CFD simulation of flow field around these parachutes is carried out,and then the CFD simulation of parachute-projectile systems is *** to the simulation results,the phenomenon is observed that in the simulations of parachutes there are two vortex-rings at the wind shadow of parachutes,however,in the second simulations of parachute-projectile systems,two additional vortex-rings emerge inside the *** to these two inner vortex-rings,the pressure inside parachutes *** a result,the drag of parachute in simulation of parachute-projectile systems is about 20% smaller compared with the prior *** order to verify the numerical results of CFD simulations,wind tunnel tests are *** terms of the data of the wind tunnel tests,the CFD simulation for flow field characteristics is reasonable and *** results of both CFD simulation and wind tunnel tests demonstrated the influence of projectile wake flow to parachute drag can not be neglected if the parachute size is on the same magnitude with *** influence to parachute drag from the ratio of projectile diameter to parachute diameter is also analyzed both in CFD simulations and wind tunnel *** approach combined CFD simulation and wind tunnel tests proposed can be used to guide the design of such parachute whose si

关键词： parachute projectile flow field computational fluid dynamics(CFD) wind tunnel test

Survey of polycyclic aromatic hydrocarbons(PAHs)in arterial street air of Hangzhou

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Journal of Environmental Sciences 2001年第1期13卷 8-13页

作者： ZHU Li zhong liu yong jian Department of Environmental Science Zhejiang UniversityHangzhou 310028China

The presence of particulate and vapor PAHs, SO2 and NOx and other interrelated conditions (temperature, traffic intensity and wind velocity) were investigated in the arterial street air of Hangzhou. The concentration of the nine PAHs in the air was mean to 11.7 μg/m3, and the content of benzo(a) pyrene was up to 0.108 μg/m3. The contents of PAHs in the sampling sites were in good relation to the traffic intensity, and would be also affected by the terrain and meteorological conditions. The occurrences of PAHs in ambient air were mainly affected by their physical, chemical characters and temperature. The three- and four-ring PAHs (MW&le228) mainly existed in the vapor phase and the five-ring PAHs (MW > 228) existed predominately in the particulate phase. The fraction of vapor PAHs in the total nine PAHs was 84.2% in the air of the sampling sites. In the morning and evening, the concentrations of PAHs in the arterial street air were higher than that on the noon and the diurnal variation of PAHs was similar to that of the traffic gas NOx. A conclusion would be drawn that the major source of PAHs in the arterial street air was the traffic. And the results indicated that 75% of BaP would come from traffic source and remaining 25% of BaP would come from non-traffic source.

关键词： polycyclic aromatic hydrocarbons arterial street air pollution