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Nonrecursive residual Monte Carlo method for S_(N) transport discretization error estimation

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Nuclear Science and Techniques 2022年第5期33卷 102-112页

作者： yun-huang Zhang Department of Physics Zhejiang UniversityHangzhou 310027China

In this paper,we present a nonrecursive residual Monte Carlo method for estimating discretization errors associated with the S_(N) transport solution to radiation transport *** this technique is general,we applied it to the mono-energetic 1-D S_(N) equation with linear-discontinuous finite element method spatial discretization as a demonstration of the theory for the purpose of this *** angular flux representations:conforming and simplified representations were considered in this analysis,and the results were *** is shown that the simplified representation dramatically reduces the memory footprint and computational complexity of residual source generation and sampling while accurately capturing the error associated with certain types of responses.

关键词： Residual Monte Carlo Discretization error Angular flux representation

MEAN-VARIANCE MODEL BASED ON FILTERS OF MINIMUM SPANNING TREE

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Journal of Systems Science and Systems Engineering 2011年第4期20卷 495-506页

作者： Feixue huang Lei SUN yun WANG 1Economics School Faculty of Management and Economics Dalian University of Technology Dalian 116024 China

This study aims to reduce the statistical uncertainty of the correlation coefficient matrix in the mean-variance model of Markowitz. A filtering algorithm based on minimum spanning tree （MST） is proposed. Daily data of the 30 stocks of the Hang Seng Index （HSI） and Dow Jones Index （DJI） from 2004 to 2009 are selected as the base dataset. The proposed algorithm is compared with the Markowitz method in terms of risk, reliability, and effective size of the portfolio. Results show that （1） although the predicted risk of portfolio built with the MST is slightly higher than that of Markowitz, the realized risk of MST filtering algorithm is much smaller; and （2） the reliability and the effective size of filtering algorithm based on MST is apparently better than that of the Markowitz portfolio. Therefore, conclusion is that filtering algorithm based on MST improves the mean-variance model of Markowitz.

关键词： Mean-variance model correlation matrix minimum spanning tree (MST) portfoliooptimization

A mechanical model for the adhesive contact with local sliding induced by a tangential force

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Acta Mechanica Solida Sinica 2017年第4期30卷 369-373页

作者： Gan-yun huang Ji-Feng Yan Department of Mechanics School of Mechanical EngineeringTianjin University

Adhesion has been demonstrated to play an important role in contact and friction between objects at small scales. While various models have been established for adhesive contact under normal forces, studies on the adhesive contact under tangential force have been far fewer, which if any, are mostly confined to the non-slipping situations. In the present work, a model has been proposed for adhesive contact with local sliding under tangential forces. Herein, the onset of local sliding in adhesive contact has been addressed by assuming the nucleation of dislocations. By analogy with the emission of dislocations at a crack tip, the critical tangential force for the onset of sliding has been determined, and its effect on the evolution of contact size has also been studied. Comparison with relevant experiments has verified the validity of the present model.

关键词： Adhesive contact Tangential force Local sliding Dislocation Contact size

Intelligent Shape-Morphing Micromachines

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Research 2021年第1期2021卷 1018-1033页

作者： Qianying Chen Pengyu Lv Jianyong huang Tian-yun huang Huiling Duan State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering ScienceBIC-ESATCollege of EngineeringPeking UniversityBeijing 100871China CAPT HEDPSPeking UniversityBeijing 100871China

Intelligent machines are capable of switching shape configurations to adapt to changes in dynamic environments and thus have offered the potentials in many applications such as precision medicine,lab on a chip,and *** though the developments of smart materials and advanced micro/nanomanufacturing are flouring,how to achieve intelligent shapemorphing machines at micro/nanoscales is still significantly challenging due to the lack of design methods and strategies especially for small-scale shape *** review is aimed at summarizing the principles and methods for the construction of intelligent shape-morphing micromachines by introducing the dimensions,modes,realization methods,and applications of shape-morphing ***,this review highlights the advantages and challenges in shape transformations by comparing micromachines with the macroscale counterparts and presents the future outlines for the next generation of intelligent shape-morphing micromachines.

关键词： machines realization dimensions

Sorption mechanism of naphthalene by diesel soot: Insight from displacement with phenanthrene/p-nitrophenol

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Journal of Environmental Sciences 2021年第8期33卷 136-146页

作者： Wenhao Wu yun huang Daohui Lin Kun Yang Department of Environmental Science Zhejiang UniversityHangzhou 310058China Key Laboratory of Environmental Pollution and Ecological Health of Ministry of Education Hangzhou 310058China Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control Hangzhou 310058China

The nonlinear sorption of hydrophobic organic contaminants(HOCs)could be changed to linear sorption by the suppression of coexisting solutes in natural system,resulting in the enhancement of mobility,bioavailability and risks of HOCs in the *** previous study,inspired from the competitive adsorption on activated carbon(AC),the displaceable fraction of HOCs sorption to soot by competitor was attributed to the adsorption on elemental carbon fraction of soot(EC-Soot),while the linear and nondisplaceable fraction was attributed to the partition in authigenic organic matter of soot(OM-Soot).In this study,however,we observed that the linear and nondisplaceable fraction of HOC(naphthalene)to a diesel soot(D-Soot)by competitor(phenanthrene or p-nitrophenol)should be attributed to not only the linear partition in OM-Soot,but also the residual linear adsorption on *** also observed that the competition on the surface of soot dominated by external surface was different from that of AC dominated by micropore surface,i.e.,complete displacement of HOCs by p-nitrophenol could occur for the micropore surface of AC,but not for the external surface of *** observations were obtained through the separation of EC-Soot and OM-Soot from D-Soot with organic-solvent extraction and the sorption comparisons of D-Soot with an AC(ACF300)and a multiwalled carbon nanotube(MWCNT30).The obtained results would give new insights to the sorption mechanisms of HOCs by soot and help to assess their environmental risks.

关键词： Competitive sorption Diesel soot Organic compounds Linearity External surface

Catalytic activity of flame-synthesized Pd/TiO2 for the methane oxidation following hydrogen pretreatments

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Particuology 2018年第6期16卷 58-64页

作者： Nafeng Wang Fang Niu Shuhao Wang yun huang State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy ofSdencesBeijing 100190China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China

A nanocatalyst composed of 10wt% Pd supported on TiO2 was synthesized using one-step flame spray pyrolysis with a highly-quenched premixed stagnation *** as-prepared nanoparticles,having a mean diameter of approximately 10nm,were then subjected to isothermal oxidation and reduction in a fixed bed *** potential roles of Pd and PdO as well as possible synergistic effects between these two active species were explored during methane *** lowest light-off temperature T20 was obtained at a Pd ratio of 53% and this result can be reasonably explained based on a surface Pd-PdO site pair ***,differences in the hysteresis behavior during methane oxidation were noted throughout a heating-cooling cycle over the temperature range of 200-600℃,such that the degree of hysteresis was strongly correlated with the Pd ratio.

关键词： Catalytic oxidation Palladium-based catalysts Flame-assisted spray pyrolysis Nanoparticles

Dynamic Installation Behaviors of A New Hybrid Plate Anchor in Layered Marine Clay

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China Ocean Engineering 2021年第5期35卷 736-749页

作者： LAI Ying ZHU Bin CHEN Chuan huang yun-han MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou 310058China Jiangsu Ocean University Lianyungang 222005China

Layered soil profiles create challenges for foundation installation and detrimentally affect the foundation *** research explored the free-fall penetration behavior of a new dynamically installed plate anchor,the Flying Wing Anchor?,in layered soil *** new concept anchor combines the advantages of low-cost installation of torpedo piles and high efficiency of plate *** is initially installed through free-fall like a torpedo pile,and followed by drag embedment like a plate *** methodology is to perform free-fall penetration tests with a model anchor in a variety of test beds containing marine clays with different profiles of undrained shear strength versus depth.A calibrated prediction model accounting for the effects of strain-rate and stiff layer produces results similar to those from the model *** design curves were developed based on the calibrated analytical model,and are valuable to estimate the impact velocity thresholds of prototype anchor to penetrate through stiff *** free-fall penetration tests indicated that the penetration ability of FWA?increases with the increased impact *** new dynamically embedded plate anchor can penetrate through the stiff layers that would cause problems for the conventional plate anchor,such as the drag embedded anchor,plowing on the top of stiff layer instead of breaking into ***,the new dynamically embedded plate anchor can provide a possible solution for layered soil profiles in deep water.

关键词： layered soils penetration hybrid anchors dynamically installed anchors plate anchors

Free-Fall Penetration Behaviors of A New Dynamically Installed Plate Anchor in Marine Clay

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China Ocean Engineering 2020年第6期34卷 795-805页

作者： LAI Ying huang yun-han CHEN Chuan ZHU Bin MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou 310058China College of Civil and Harbour Engineering Jiangsu Ocean UniversityLianyungang 222005China

A new dynamically installed plate anchor, the Flying Wing Anchor~?, has been developed as a sustainable anchor concept for deep-water offshore wind turbines. The anchor is firstly installed by free-fall penetration and then followed by drag embedment. If the anchor is subjected to environmental loads, it dives deeper to mobilize a higher capacity. This study presents a series of free-fall penetration tests with model anchors in different weights to assess the anchor behavior during the free-fall penetration performance in one-layer soil with a constant shear strength profile. Anchor velocities and embedment depths were measured by a magnetometer. An energy-based model and a force-based model were calibrated against the test results of model anchors with different weights. Based on the calibrated force-based model, a series of design charts were developed to estimate the embedment depth of anchors in different sizes and with different impact velocities in various marine clays. The framework to plot design charts presented herein can be potentially applied to other dynamically installed anchors to predict embedment depth in engineering practice.

关键词： dynamic anchor dynamic installation plate anchor scale effect design chart

Numerical study on roll dynamics of damaged ship in beam waves and calm water

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Journal of Hydrodynamics 2023年第3期35卷 482-497页

作者： Zhi-yun huang Zhi-liang Gao Sang-ming Xu Key Laboratory of High Performance Ship Technology Ministry of Education Wuhan University of TechnologyWuhan 430063China Wuhan University of Technology College of Marine and Energy Power EngineeringWuhan 430063China Union Strong(Beijing)Technology Co. LtdBeijing 100176China

Computational fluid dynamics is used to study the roll dynamics of a damaged ship in beam waves with various steepnesses and in calm *** wave-making method,which combines the velocity-inlet boundary and momentum source with the fifth-order Stokes theory,is employed for wave *** SST k-ωturbulence model with a modification to the turbulent viscosity in Reynolds stress is adopted to prevent the over-production of turbulence in the numerical wave *** lateral drift restrained model with a combined dynamic mesh strategy is utilized to deal with the coupled heave-sway-roll motions of the ***,benchmarking tests are performed,including wave generation and roll response of the damaged ship in regular beam ***,the effects of incident wave steepness on the roll response of the damaged ship are *** different wave steepnesses,the ship roll motion is dominated by the first-order harmonic *** second-order component increases with the increase of wave ***,the roll hydrodynamic coefficients for different parts of the damaged ship are investigated with different rolling *** added moment of inertia for the whole damaged ship is mainly attributed to the external hull composition and changes slightly with the change of roll amplitude and *** added moment of inertia for the compartments could be negative in particular *** damping coefficients of the whole damaged ship and external hull increase with the increase of roll amplitude and frequency,while that of the compartments appears complicated with the change of roll amplitude and frequency.

关键词： Damaged ship roll dynamics wave steepness hydrodynamic coefficients computational fluid dynamics(CFD)