资源类型

期刊论文 177

年份

2024 1

2023 10

2022 16

2021 16

2020 13

2019 7

2018 8

2017 9

2016 8

2015 7

2014 4

2013 10

2012 5

2011 13

2010 11

2009 11

2008 4

2007 7

2006 2

2005 2

展开 ︾

关键词

动力学 4

系统动力学 3

COVID-19 2

岩石动力学 2

航天器 2

评价 2

Tetrasphaera 1

Fitzhugh-Nagumo；混沌；分数阶；磁通量 1

NNI 1

SEIHR动力学模型 1

SEIR+Q传染病动力学模型 1

SPH 1

UNI 1

一般力学 1

上限法 1

丝孢堆黑粉菌 1

中高频响应 1

临床医疗资源需求 1

临床诊断标准 1

展开 ︾

检索范围：

排序： 展示方式：

Effects of seeding nucleation agent on geopolymerization process of fly-ash geopolymer

Lapyote PRASITTISOPIN, Issara SEREEWATTHANAWUT

《结构与土木工程前沿（英文）》 2018年 第12卷 第1期   页码 16-25 doi: 10.1007/s11709-016-0373-7

摘要： Geopolymer, an inorganic aluminosilicate material activated by alkaline medium solution, can perform as an inorganic adhesive. The geopolymer technology has a viability to substitute traditional concrete made of portland cement (PC) because replacing PC with fly ash leads to reduced carbon dioxide emissions from cement productions and reduced materials cost. Although fly ash geopolymer stimulates sustainability, it is slow geopolymerization reaction poses a challenge for construction technology in term of practicality. The development of increasing geopolymerization reaction rate of the geopolymer is needed. ?The purpose of this study is to evaluate seeding nucleation agents (NA) of fly ash geopolymer that can accelerate polymerization reactions such that the geopolymer can be widely used in the construction industry. Results from the present study indicate that the use of NA (i.e., Ca(OH) ) can be potentially used to increase geopolymerization reaction rate and improve performance characteristics of the fly ash geopolymer product.

关键词： fly ash     geopolymer     nucleation agent     portland cement replacement    

HTML PDF 收藏

Primary nucleation of lithium carbonate

Yuzhu SUN, Xingfu SONG, Jin WANG, Yan LUO, Jianguo YU

《化学科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 73-77 doi: 10.1007/s11705-009-0091-y

摘要： A set of laser apparatus was used to explore the induction period and the primary nucleation of lithium carbonate. Results show that the induction period increases with the decrease of supersaturation, temperature and stirring speed. Through the classical theory of primary nucleation, many important properties involved in primary nucleation under different conditions were obtained quantitatively, including the interfacial tension between solid and liquid, contact angle, critical nucleus size, critical nuleation free energy etc.

关键词： lithium carbonate     primary nucleation     reactive crystallization     induction period    

HTML PDF 收藏

Ultrafast solid-liquid-vapor phase change of a thin gold film irradiated by femtosecond laser pulses and pulse trains

Jing HUANG, Yuwen ZHANG, J. K. CHEN, Mo YANG

《能源前沿（英文）》 2012年 第6卷 第1期   页码 1-11 doi: 10.1007/s11708-012-0179-9

摘要： Effects of different parameters on the melting, vaporization and resolidification processes of thin gold film irradiated by femtosecond pulses and pulse train were systematically studied. The classical two-temperature model was adopted to depict the non-equilibrium heat transfer in electrons and lattice. The melting and resolidification processes, which was characterized by the solid-liquid interfacial velocity, as well as elevated melting temperature and depressed solidification temperature, was obtained by considering the interfacial energy balance and nucleation dynamics. Vaporization process which leads to ablation was described by tracking the location of liquid-vapor interface with an iterative procedure based on energy balance and gas kinetics law. The parameters in discussion included film thickness, laser fluence, pulse duration, pulse number, repetition rate, pulse train number, etc. Their effects on the maximum lattice temperature, melting depth and ablation depth were discussed based on the simulation results.

关键词： melting     evaporation     nucleation dynamics     nanoscale heat transfer    

HTML PDF 收藏

Numerical study and control method of interaction of nucleation and boundary layer separation in condensing

Liansuo AN , Zhi WANG , Zhonghe HAN ,

《能源前沿（英文）》 2009年 第3卷 第3期   页码 254-261 doi: 10.1007/s11708-009-0047-4

摘要： The spontaneous nucleation flow in turbine cascade was numerically studied. The model was implemented within a full Navier–Stokes viscous flow solution procedure and the process of condensation was calculated by the quadrature method of moments that shows good accuracy with very broad size distributions. Results were presented for viscous and inviscous flow, showing the influence of boundary layer separation and wake vortices on spontaneous nucleation. The results show that the degree of flow separation in wet steam flow is greater than that in superheated steam flow due to condensation shock and that the loss cannot be neglected. Furthermore, the impact of boundary layer separation and wake vortices on velocity profiles and its implications for profile loss were considered. The calculations showed that layer separation and wake vortices influence nucleation rate, leading to different droplet distributions. A method for controlling homogeneous nucleation and for reducing degree of flow separation in high-speed transonic wet steam flow was presented. The liquid phase parameter distribution is sensitive to the suction side profile of turbine cascade, which impacts the nucleation rate distribution leading to different droplet distributions and affects the degree of flow separation. The numerical study provides a practical design method for turbine blade to reduce wetness losses.

关键词： wet steam     two-phase flow     spontaneous condensation     numerical simulation     flow separation     profile loss    

HTML PDF 收藏

Nucleation and growth mechanism of cefodizime sodium at different solvent compositions

Xinwei ZHANG, Shudong ZHANG, Xiaodan SUN, Zequn YIN, Quanjie LIU, Xiwen ZHANG, Qiuxiang YIN

《化学科学与工程前沿（英文）》 2013年 第7卷 第4期   页码 490-495 doi: 10.1007/s11705-013-1350-5

摘要： The induction time of cefodizime sodium was measured in ethanol-water at different solvent compositions by the laser technology measurement. The results indicate that the solvent composition played an important role in the supersaturation and the nucleation process of cefodizime sodium solution. According to the modified classical nucleation theory, the nucleation and growth mechanism were identified. The correlation results show that heterogeneous nucleation dominated the nucleation process at lower supersaturation, where homogeneous nucleation is the most important mechanism at higher supersaturation. Based on the correlated results, the 2D mediated growth mechanism had the highest correlation coefficients ( ), so this mechanism was selected as the proper growth mechanism for cefodizime sodium.

关键词： cefodizime sodium     induction time     primary nucleation     growth mechanism    

HTML PDF 收藏

Interfacial induction and regulation for microscale crystallization process: a critical review

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 838-853 doi: 10.1007/s11705-021-2129-8

摘要： Microscale crystallization is at the frontier of chemical engineering, material science, and biochemical research and is affected by many factors. The precise regulation and control of microscale crystal processes is still a major challenge. In the heterogeneous induced nucleation process, the chemical and micro/nanostructural characteristics of the interface play a dominant role. Ideal crystal products can be obtained by modifying the interface characteristics, which has been proven to be a promising strategy. This review illustrates the application of interface properties, including chemical characteristics (hydrophobicity and functional groups) and the morphology of micro/nanostructures (rough structure and cavities, pore shape and pore size, surface porosity, channels), in various microscale crystallization controls and process intensification. Finally, possible future research and development directions are outlined to emphasize the importance of interfacial crystallization control and regulation for crystal engineering.

关键词： interfacial crystallization     heterogeneous nucleation     supersaturation     micro/nanostructure     process control and intensification    

HTML PDF 收藏

Computational fluid dynamics simulation of aerosol transport and deposition

Yingjie TANG, Bing GUO

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 362-377 doi: 10.1007/s11783-011-0365-8

摘要： In this article computational fluid dynamics (CFD) simulation of aerosol transport and deposition, i.e. the transport and deposition of particles in an aerosol, is reviewed. The review gives a brief account of the basics of aerosol mechanics, followed by a description of the general CFD approach for flow field simulation, turbulence modeling, wall treatments and simulation of particle motion and deposition. Then examples from the literature are presented, including CFD simulation of particle deposition in human respiratory tract and particle deposition in aerosol devices. CFD simulation of particle transport and deposition may provide information that is difficult to obtain through physical experiments, and it may help reduce the number of experiments needed for device design. Due to the difficulty of describing turbulent flow and particle-eddy interaction, turbulent dispersion of particles remains one of the greatest challenges for CFD simulation. However, it is possible to take a balanced approach toward quantitative description of aerosol dispersion using CFD simulation in conjunction with empirical relations.

关键词： computational fluid dynamics (CFD)     aerosol     transport     deposition    

HTML PDF 收藏

Recent developments in passive interconnected vehicle suspension

Wade A. SMITH, Nong ZHANG,

《机械工程前沿（英文）》 2010年 第5卷 第1期   页码 1-18 doi: 10.1007/s11465-009-0092-z

摘要： This paper presents an overall review on the historical concept development and research advancement of passive hydraulically interconnected suspension (HIS) systems. It starts with an introduction to passive HIS systems and their various incarnations developed over many decades. Next, a description is provided of a recently proposed multidisciplinary approach for the frequency-domain analysis of vehicles fitted with an HIS. The experimental validation and applications of the method to both free and forced vibration analysis are discussed based on a simplified, roll-plane half-car model. A finite-element-method-based approddach for modelling the transient dynamics of an HIS vehicle is also briefly outlined. In addition, recent work on the investigation of NVH associated with HIS-equipped vehicles is mentioned. Discussion is then provided on future work to the further understanding of HIS and its applications. The paper concludes that interconnected suspension schemes can provide much greater flexibility to independently specify modal stiffness and damping parameters – a characteristic unique among passive suspensions. It points out that there is a need for system optimisation, and there are troublesome NVH issues that require solutions. It suggests that further research attention and effort be paid to NVH issues and system level optimisation to gain a greater understanding of HIS and to broaden its applications.

关键词： interconnected suspensions     rollover prevention     vehicle dynamics     ride comfort     multibody system dynamics     hydraulic system dynamics    

HTML PDF 收藏

Nonlinear dynamics of a wind turbine tower

A. GESUALDO, A. IANNUZZO, F. PENTA, M. MONACO

《机械工程前沿（英文）》 2019年 第14卷 第3期   页码 342-350 doi: 10.1007/s11465-019-0524-3

摘要： The recent proliferation of wind turbines has revealed problems in their vulnerability under different site conditions, as evidenced by recent collapses of wind towers after severe actions. Analyses of structures subjected to variable actions can be conducted through several methods with different accuracy levels. Nonlinear dynamics is the most reliable among such methods. This study develops a numerical procedure to obtain approximate solutions for rigid-plastic responses of structures subjected to base harmonic pulses. The procedure’s model is applied to a wind turbine tower subjected to inertial forces generated by harmonic ground acceleration, and failure is assumed to depend on the formation of shear hinges. The proposed approach provides an efficient representation of the post-elastic behavior of the structure, has a low computational cost and high effectiveness, and uses a limited number of mechanical parameters.

关键词： nonlinear dynamics     plastic shear failure     modal approximation     time history    

HTML PDF 收藏

Effect of ligand chain length on hydrophobic charge induction chromatography revealed by molecular dynamics

Lin ZHANG, Yan SUN

《化学科学与工程前沿（英文）》 2013年 第7卷 第4期   页码 456-463 doi: 10.1007/s11705-013-1357-y

摘要： Hydrophobic charge induction chromatography (HCIC) is a mixed-mode chromatography which is advantageous for high adsorption capacity and facile elution. The effect of the ligand chain length on protein behavior in HCIC was studied. A coarse-grain adsorbent pore model established in an earlier work was modified to construct adsorbents with different chain lengths, including one with shorter ligands (CL2) and one with longer ligands (CL4). The adsorption, desorption, and conformational transition of the proteins with CL2 and CL4 were examined using molecular dynamics simulations. The ligand chain length has a significant effect on both the probability and the irreversibility of the adsorption/desorption. Longer ligands reduced the energy barrier of adsorption, leading to stronger and more irreversible adsorption, as well as a little more unfolding of the protein. The simulation results elucidated the effect of the ligand chain length, which is beneficial for the rational design of adsorbents and parameter optimization for high-performance HCIC.

关键词： adsorption     desorption     irreversibility     protein conformational transition     molecular dynamics simulation    

HTML PDF 收藏

Applying system dynamics to strategic decision making in construction

SangHyun LEE

《工程管理前沿（英文）》 2017年 第4卷 第1期   页码 35-40 doi: 10.15302/J-FEM-2017002

摘要： The author discusses the application of System Dynamics to high-level strategic simulation in construction. In particular, System Dynamics’ strength on representing feedback processes, aggregation, soft variables, and continuous simulation clock for high-level simulation are discussed using real modeling examples. From this exercise, it is concluded that System Dynamics offers a great potential for strategic simulation in construction. Further, the author proposes a comprehensive simulation framework that integrates System Dynamics and Discrete Event Simulation for a strategic decision making process in construction where operational details should be taken into account.

关键词： strategic project management     construction management     system dynamics     feedback process     hybrid simulation    

HTML PDF 收藏

Model reduction of contact dynamics simulation using a modified Lyapunov balancing method

Jianxun LIANG, Ou MA, Caishan LIU

《机械工程前沿（英文）》 2011年 第6卷 第4期   页码 383-391 doi: 10.1007/s11465-011-0244-9

摘要：

Finite element models are often used to simulate impact and contact dynamics responses of multibody dynamical systems. However, such a simulation remains very inefficient because very small integration time step must be used when solving the involved differential equations, especially when the involved contact stiffness is high. Although many model reduction techniques have been available to improve the efficiency of finite element based simulations, these techniques cannot be readily applied to contact dynamics simulations due to the high nonlinearity of the contact dynamics models. This paper presents a model reduction approach for finite-element based multibody contact dynamics simulation, based on a modified Lyapunov balanced truncation method. An example is presented to demonstrate that, by applying the model reduction the simulation process is significantly speeded up and the resulting error is bounded within an acceptable level. The performance of the method with respect to some influential factors such as element size, shape and contact stiffness is also investigated.

关键词： contact dynamics     dynamic simulation     model reduction     finite element method    

HTML PDF 收藏

Synthesis of crystals and particles by crystallization and polymerization in droplet-based microfluidic devices

Jingtao WANG, Jin ZHANG, Junjie HAN,

《化学科学与工程前沿（英文）》 2010年 第4卷 第1期   页码 26-36 doi: 10.1007/s11705-009-0292-4

摘要： The recent advances in crystallization and polymerization assisted by droplet-based microfluidics to synthesize micro-particles and micro-crystals are reviewed in this paper. Droplet-based microfluidic devices are powerful tools to execute some precise controls and operations on the flow inside microchannels by adjusting fluid dynamics parameters to produce monodisperse emulsions or multiple-emulsions of various materials. Major features of this technique are producing particles of monodispersity to control the shape of particles in a new level, and to generate droplets of diverse materials including aqueous solutions, gels and polymers. Numerous microfluidic devices have been employed to generate monodisperse droplets of range from nm to μm, such as T junctions, flow-focusing devices and co-flow or cross-flow capillaries. These discrete, independently controllable droplets are ideal microreactors to be manipulated in the channels to synthesize the nanocrystals, protein crystals, polymer particles and microcapsules. The generated monodisperse particles or crystals are to meet different technical demands in many fields, such as crystal engineering, encapsulation and drug delivery systems. Microfluidic devices are promising tools in the synthesis of micron polymer particles that have diverse applications such as the photonic materials, ion-exchange and chromatography columns, and field-responsive rheological fluids. Processes assisted by microfluidic devices are able to produce the polymer particles (including Janus particles) with precise control over their sizes, size distribution, morphology and compositions. The technology of microfluidics has also been employed to generate core-shell microcapsules and solid microgels with precise controlled sizes and inner structures. The chosen “smart” materials are sensitive to an external stimulus such as the change of the pH, electric field and temperature. These complex particles are also able to be functionalized by encapsulating nanoparticles of special functions and by attaching some special groups like targeting ligands. The nucleation kinetics of some crystals like KNO was investigated in different microfluidic devices. Because of the elimination of the interactions among crystallites in bulk systems, using independent droplets may help to measure the nucleation rate more accurately. In structural biology, the droplets produced in microfluidic devices provide ideal platforms for protein crystallization on the nanoliter scale. Therefore, they become one of the promising tools to screen the optimal conditions of protein crystallization.

关键词： core-shell     monodisperse     nucleation     Microfluidic     different technical    

HTML PDF 收藏

Nonlinear dynamics and analysis of a four-bar linkage with clearance

Yuanguang TANG, Zongyu CHANG, Xiaogang DONG, Yafei HU, Zhenjiang YU

《机械工程前沿（英文）》 2013年 第8卷 第2期   页码 160-168 doi: 10.1007/s11465-013-0258-6

摘要：

In this paper, nonlinear dynamic behavior of a four-bar linkage considering clearance is studied. The dynamic model of the linkage with a clearance between coupler and rocker is developed firstly. Then the dynamic equations of this mechanism are solved by a numerical method. According to the calculated response, compliance, force and trajectory of pin in joint bearing are obtained. Effects of clearance magnitude and the relationship between a mechanism with clearance and without clearance are studied. By using Poincare Map, it is proved that strange attractors or chaos exist in the dynamic response. In addition, phenomena of chaos, periodic response and subharmonic response also can be found in the special condition. Bifurcation diagram is used to suggest that bifurcation and fractal phenomena exist in the dynamic response of this mechanism.

关键词： four-bar linkage     chaos     bifurcation     strange attractors     dynamics    

HTML PDF 收藏

Water film coated composite liquid metal marble and its fluidic impact dynamics phenomenon

Yujie DING,Jing LIU

《能源前沿（英文）》 2016年 第10卷 第1期   页码 29-36 doi: 10.1007/s11708-015-0388-0

摘要： A composite liquid metal marble made of metal droplet coated with water film was proposed and its impact dynamics phenomenon was disclosed. After encapsulating the liquid metal into water droplets, the fabricated liquid marble successfully avoided being oxygenized by the metal fluid and thus significantly improved its many physical capabilities such as surface tension modification and shape control. The striking behaviors of the composite liquid metal marbles on a substrate at room temperature were experimentally investigated in a high speed imaging way. It was disclosed that such marbles could disintegrate, merge, and even rebound when impacting the substrate, unlike the existing dynamic fluidic behaviors of liquid marble or metal droplet. The mechanisms lying behind these features were preliminarily interpreted. This fundamental finding raised profound multiphase fluid mechanics for understanding the complex liquid composite which was also critical for a variety of practical applications such as liquid metal jet cooling, inkjet printed electronics, 3D printing or metal particle fabrication etc.

关键词： liquid metal marble     metallic droplet     composite fluid     impact dynamics     multiphase fluid mechanics    

HTML PDF 收藏

标题 作者 时间 类型 操作

Effects of seeding nucleation agent on geopolymerization process of fly-ash geopolymer

Lapyote PRASITTISOPIN, Issara SEREEWATTHANAWUT

期刊论文

Primary nucleation of lithium carbonate

Yuzhu SUN, Xingfu SONG, Jin WANG, Yan LUO, Jianguo YU

期刊论文

Ultrafast solid-liquid-vapor phase change of a thin gold film irradiated by femtosecond laser pulses and pulse trains

Jing HUANG, Yuwen ZHANG, J. K. CHEN, Mo YANG

期刊论文

Numerical study and control method of interaction of nucleation and boundary layer separation in condensing

Liansuo AN , Zhi WANG , Zhonghe HAN ,

期刊论文

Nucleation and growth mechanism of cefodizime sodium at different solvent compositions

Xinwei ZHANG, Shudong ZHANG, Xiaodan SUN, Zequn YIN, Quanjie LIU, Xiwen ZHANG, Qiuxiang YIN

期刊论文

Interfacial induction and regulation for microscale crystallization process: a critical review

期刊论文

Computational fluid dynamics simulation of aerosol transport and deposition

Yingjie TANG, Bing GUO

期刊论文

Recent developments in passive interconnected vehicle suspension

Wade A. SMITH, Nong ZHANG,

期刊论文

Nonlinear dynamics of a wind turbine tower

A. GESUALDO, A. IANNUZZO, F. PENTA, M. MONACO

期刊论文

Effect of ligand chain length on hydrophobic charge induction chromatography revealed by molecular dynamics

Lin ZHANG, Yan SUN

期刊论文

Applying system dynamics to strategic decision making in construction

SangHyun LEE

期刊论文

Model reduction of contact dynamics simulation using a modified Lyapunov balancing method

Jianxun LIANG, Ou MA, Caishan LIU

期刊论文

Synthesis of crystals and particles by crystallization and polymerization in droplet-based microfluidic devices

Jingtao WANG, Jin ZHANG, Junjie HAN,

期刊论文

Nonlinear dynamics and analysis of a four-bar linkage with clearance

Yuanguang TANG, Zongyu CHANG, Xiaogang DONG, Yafei HU, Zhenjiang YU

期刊论文

Water film coated composite liquid metal marble and its fluidic impact dynamics phenomenon

Yujie DING,Jing LIU

期刊论文