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Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

《结构与土木工程前沿(英文)》   页码 915-934 doi: 10.1007/s11709-023-0907-8

摘要: A fictitious soil pile (FSP) model is developed to simulate the behavior of pipe piles with soil plugs undergoing high-strain dynamic impact loading. The developed model simulates the base soil with a fictitious hollow pile fully filled with a soil plug extending at a cone angle from the pile toe to the bedrock. The friction on the outside and inside of the pile walls is distinguished using different shaft models, and the propagation of stress waves in the base soil and soil plug is considered. The motions of the pile−soil system are solved by discretizing them into spring-mass model based on the finite difference method. Comparisons of the predictions of the proposed model and conventional numerical models, as well as measurements for pipe piles in field tests subjected to impact loading, validate the accuracy of the proposed model. A parametric analysis is conducted to illustrate the influence of the model parameters on the pile dynamic response. Finally, the effective length of the FSP is proposed to approximate the affected soil zone below the pipe pile toe, and some guidance is provided for the selection of the model parameters.

关键词: fictitious soil pile     soil plug     pipe piles     high-strain dynamic analysis     one-dimensional wave theory     pile dynamics    

Comparison of combustion characteristics of petroleum coke and coal in one-dimensional furnace

Qulan ZHOU, Qinxin ZHAO, Guangjie ZHOU, Huiqing WANG, Tongmo XU, Shien HUI,

《能源前沿(英文)》 2010年 第4卷 第3期   页码 436-442 doi: 10.1007/s11708-009-0059-0

摘要: The effect of primary air fraction , outer secondary air swirl strength and excess oxygen coefficient on the combustion characteristics of petroleum coke, Hejin lean coal and Shenmu soft coal are researched on a one-dimensional furnace using a dual channel swirl burner. The results show that with the increase in primary air fraction , the NO emission concentrations of both Hejin lean coal and petroleum coke increase, and the combustion worsens in the earlier stage, but the burn-out rate of Shenmu soft coal is improved. The NO emission concentration obtains a minimum value with an increase in . The ignition and burn-out rate of petroleum coke and Shenmu soft coal are optimal when Ω is minimum and Ω=0.87, respectively. However, both the NO emission concentration of petroleum coke and Shenmu soft coal are minimum when Ω=1.08. The increase in excess oxygen coefficient delays the ignition of petroleum coke, worsens the combustion condition and increases the NO emission concentration, but it greatly decreases the NO emission concentration of Shenmu soft coal.

关键词: petroleum coke     Shenmu soft coal     Hejin lean coal     combustion characteristics     experimental research    

基于一维纳米结构阵列的质子交换膜燃料电池电极设计的研究进展 Review

杜尚峰

《工程(英文)》 2021年 第7卷 第1期   页码 33-49 doi: 10.1016/j.eng.2020.09.014

摘要:

一维(1D)铂基电催化剂对氧还原反应(ORR)展现出了良好的催化活性和稳定性。基于一维铂基纳米结构阵列的三维(3D)有序电极的研究进展表明,它们在解决现有铂/碳(Pt/C)纳米颗粒电极在高性能质子交换膜燃料电池(PEMFC)的传质特性和持久性挑战方面具有巨大的潜力。本文综述了该领域的最新进展,重点介绍了基于独立的铂纳米线阵列的三维有序结构电极,讨论了纳米结构薄膜(NSTF)催化剂以及沉积在聚合物纳米线、碳和二氧化钛纳米管阵列上的铂基纳米颗粒电极,并回顾了铂基纳米管阵列电极的研究进展。本文指出了一维催化剂纳米结构的尺寸、表面性质和分配控制的重要性。最后,讨论了一维纳米结构阵列电极在增大电化学比表面积(ECSA)和氧传质阻力定量研究方面面临的挑战和未来的发展机遇。

关键词: 质子交换膜燃料电池(PEMFC)     电极     一维(1D)     氧还原反应(ORR)     催化剂     有序化    

One-dimensional consolidation of over-consolidated soil under time-dependent loading

XIE Kanghe, WANG Kun, CHEN Guohong, HU Anfeng

《结构与土木工程前沿(英文)》 2008年 第2卷 第1期   页码 67-72 doi: 10.1007/s11709-008-0009-7

摘要: The problem of one-dimensional consolidation of over-consolidated saturated soil under time-dependent loading was studied based on semi-analytical method. The relevant computer code was developed by FORTRAN programming, and one-dimensional consolidation behavior of over-consolidated soil was investigated. It is shown that, unlike this described by traditional Terzaghi’s consolidation theory, the rate of excess pore water pressure dissipation is different from that of settlement developing. The magnitude of load and that of pre-consolidation pressure as well as the loading rate has all significant influence on consolidation. With the increasing of pre-consolidation pressure and loading rate, the rate of consolidation increases correspondingly. However, an increase in load will slow down the consolidation rate.

关键词: different     FORTRAN programming     Terzaghi ’     pre-consolidation     magnitude    

Simplified analytical solution for free vibration characteristics of Hardfill dam

XIAO Wei, HE Yunlong, ZHANG Yanfeng

《结构与土木工程前沿(英文)》 2008年 第2卷 第3期   页码 219-225 doi: 10.1007/s11709-008-0037-3

摘要: Formulas for computing natural frequencies and modes of Hardfill dams are derived based on one-dimensional shear wedge theory, in which the influences of the upstream concrete face and hydrodynamic pressure of water on the dams’ natural frequencies and modes are discussed. Furthermore, the seismic responses of Hardfill dams are calculated using response spectrum method. An example is analyzed to compare the differences of natural frequencies and modes between shear wedge method and FEM. Then the applicability and accuracy of shear wedge method to analyze free vibration characteristics of Hardfill dams are proven.

关键词: upstream concrete     hydrodynamic pressure     vibration     one-dimensional     applicability    

Experimental study for the stratified to slug flow regime transition mechanism of gas-oil two-phase flow in horizontal pipe

LIU Yiping, YANG Weilin, WANG Jing

《能源前沿(英文)》 2008年 第2卷 第2期   页码 152-157 doi: 10.1007/s11708-008-0012-7

摘要: Theoretical relations that predict the transition from a stratified pattern to a slug pattern, including a one-dimensional wave model that contains less empiricism than the commonly used Taitel-Dukler model, and the ideal model for stratified flow for the gas-liquid flow in horizontal pipes are presented. Superficial velocities of each phase, as the onset of slugging occurs, were predicted, and theoretical analysis was conducted on the stratified to slug flow regime transition. The friction, existing between the fluid and pipe wall, and on the interface of two phases, was especially taken into account. A theoretical model was applied to an experiment about air-oil two-phase flow in a 50 mm horizontal pipe. The effect of pipe diameter on the transition was also studied. The results show that this approach gives a reasonable prediction over the whole range of flow rates, and better agreement has been achieved between predicted and measured critical parameters.

关键词: two-phase     Superficial     reasonable prediction     one-dimensional     gas-liquid    

Modeling and simulation of biomass air-steam gasification in a fluidized bed

KONG Xiaoying, WU Chuangzhi, YUAN Zhenhong, MA Longlong, CHANG Jie, LÜ Pengmei

《化学科学与工程前沿(英文)》 2008年 第2卷 第2期   页码 209-213 doi: 10.1007/s11705-008-0039-7

摘要: By considering the features of fluidized-bed reactors and the kinetic mechanism of biomass gasification, a steady-state, isothermal, one-dimensional and two-phase mathematical model of biomass gasification kinetics in bubbling fluidized beds was developed. The model assumes the existence of two phases – a bubble and an emulsion phase – with chemical reactions occurring in both phases. The axial gas dispersion in the two phases is accounted for and the pyrolysis of biomass is taken to be instantaneous. The char and gas species CO, CO, H, HO, CH and 8 chemical reactions are included in the model. The mathematical model belongs to a typical boundary value problem of ordinary differential equations and its solution is obtained by a Matlab program. Utilizing wood powder as the feedstock, the calculated data show satisfactory agreement with experimental results and proves the effectiveness and reliability of the model.

关键词: satisfactory agreement     two-phase mathematical     one-dimensional     pyrolysis     calculated    

A numerical study of helium-heated inorganic membrane reformer coupling to HTGR

YIN Huaqiang, JIANG Shengyao, JU Huaiming, ZHANG Youjie

《能源前沿(英文)》 2007年 第1卷 第4期   页码 446-450 doi: 10.1007/s11708-007-0065-3

摘要: Based on one-dimensional quasi-homogeneous model, a steady-state model and its computer program were developed for helium-heated inorganic membrane reformer coupling to high temperature gas-cooled reactor (HTGR). The results show

关键词: temperature gas-cooled     one-dimensional quasi-homogeneous     steady-state     helium-heated    

Study on wave rotor refrigerators

Yuqiang DAI, Dapeng HU, Meixia DING

《化学科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 83-87 doi: 10.1007/s11705-009-0075-y

摘要: As a novel generation of a rotational gas wave machine, the wave rotor refrigerator (WRR) is an unsteady flow device used for refrigeration, in whose passages pressured streams directly contact and exchange energy due to the movement of pressure waves. In this paper, the working mechanism and refrigeration principle are investigated based on the one-dimensional unsteady flow theory. A basic limitation on main structural parameters and operating parameters is deduced and the wave diagram of WRR to guide designing is sketched. The main influential factors are studied through an experiment. In the DUT Gas Wave Refrigeration Studying and Development Center (GWRSDC) lab, the isentropic efficiency can now reach about 65%. The results show that the WRR is a feasible and promising technology in pressured gas refrigeration cases.

关键词: wave rotor     refrigeration     unsteady flow theory     wave diagram    

Lamb wave propagation modeling for structure health monitoring

Xiaoyue ZHANG, Shenfang YUAN, Tong HAO

《机械工程前沿(英文)》 2009年 第4卷 第3期   页码 326-331 doi: 10.1007/s11465-009-0045-6

摘要: This study aims to model the propagation of Lamb waves used in structure health monitoring. A number of different numerical computational techniques have been developed for wave propagation studies. The local interaction simulation approach, used for modeling sharp interfaces and discontinuities in complex media (LISA/SIM theory), has been effectively applied to numerical simulations of elastic wave interaction. This modeling is based on the local interaction simulation approach theory and is finally accomplished through the finite elements software Ansys11. In this paper, the Lamb waves propagating characteristics and the LISA/SIM theory are introduced. The finite difference equations describing wave propagation used in the LISA/SIM theory are obtained. Then, an anisotropic metallic plate model is modeled and a simulating Lamb waves signal is loaded on. Finally, the Lamb waves propagation modeling is implemented.

关键词: Lamb wave     modeling     LISA/SIM theory     finite difference equation     finite element    

工程科学领域的发展与现代物理学

宋文淼

《中国工程科学》 2004年 第6卷 第9期   页码 14-19

摘要:

从工程科学发展的角度探讨了相对论、量子理论和宏观物理学之间的关系,它们之间的矛盾和共同点,以及如何在共同的发展中寻找建立更加深刻的物理理论的可能途经。

关键词: 相对论     量子理论     工程科学     波函数空间     波粒二象性    

Reliability assessment of three-dimensional bearing capacity of shallow foundation using fuzzy set theory

Rajarshi PRAMANIK, Dilip Kumar BAIDYA, Nirjhar DHANG

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 478-489 doi: 10.1007/s11709-021-0698-8

摘要: The aim of this study is to investigate the applicability of reliability theory on surface square/rectangular footing against bearing capacity failure using fuzzy set theory in conjunction with the finite element method. Soil is modeled as a three-dimensional spatially varying medium, where its parameters (cohesion, friction angle, unit weight, etc.) are considered as fuzzy variables that maintain some membership functions. Soil is idealized as an elastic-perfectly plastic material obeying the Mohr–Coulomb failure criterion, where both associated and non-associated flow rules are considered in estimating the ultimate bearing capacity of the footing. The spatial variability of the soil is incorporated for both isotropic and anisotropic fields, which are determined by the values of scales of fluctuation in both the horizontal and vertical directions. A new parameter namely, limiting applied pressure at zero failure probability is proposed, and it indirectly predicts the failure probability of the footing. The effect of the coefficient of variation of the friction angle of the soil on the probability of failure is analyzed, and it is observed that the effect is significant. Furthermore, the effect of the scale of fluctuation on the probability of failure is investigated, and the necessity for considering spatial variability in the reliability analysis is well proven.

关键词: finite element method     square footing     reliability analysis     fuzzy set theory     coefficient of variation     spatial variability    

波粒二象性理论的若干问题

黄志洵

《中国工程科学》 2002年 第4卷 第1期   页码 54-63

摘要:

论述了光波和物质波的波粒二象性理论的发展,讨论了该理论的存留问题。认为光子的静质量和光子的内部结构仍是科学中的关键性疑点。指出,虽然波粒二象性成立的前提是波长足够小,但在现有理论中却提不出一条清晰的界线。讨论了光波和电磁波是物质还是物质属性的问题。提出了对de Broglie波超光速相速的疑问。分析表明,如何建立电磁脉冲的粒子形象的问题仍需解决。此外,探讨了当电磁脉冲以超光速传播时相对论是否受破坏。最后,讨论了消失波的粒子性和虚光子问题。

关键词: 光子     光波     物质波     波粒二象性     孤子     电磁脉冲     超光速     消失波     虚光子    

An Internet-of-Things Initiative for One Belt One Road (OBOR)

Li Da Xu

《工程管理前沿(英文)》 2016年 第3卷 第3期   页码 206-223 doi: 10.15302/J-FEM-2016039

摘要: A wide range of industrial Internet of Things (IoT) applications have been developed and deployed in recent years. IoT has provided a promising opportunity to build powerful industrial systems and applications by leveraging the growing ubiquity of RFID, wireless, mobile and sensor devices. In an effort to understand the development of IoT in industries, this paper reviews the current research of IoT, key enabling technologies, major IoT applications in industries, and identifies research trends and challenges. As IoT has received support from governments and businesses across the globe, IoT will also greatly impact One Belt One Road (OBOR) in foreseeable future.

关键词: Internet of Things (IoT)     RFID     Wireless Sensor Networks     Near Field Communications     ICT    

Responses to emerging and re-emerging infectious diseases: One world, One health

null

《医学前沿(英文)》 2018年 第12卷 第1期   页码 1-2 doi: 10.1007/s11684-018-0619-y

标题 作者 时间 类型 操作

Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

期刊论文

Comparison of combustion characteristics of petroleum coke and coal in one-dimensional furnace

Qulan ZHOU, Qinxin ZHAO, Guangjie ZHOU, Huiqing WANG, Tongmo XU, Shien HUI,

期刊论文

基于一维纳米结构阵列的质子交换膜燃料电池电极设计的研究进展

杜尚峰

期刊论文

One-dimensional consolidation of over-consolidated soil under time-dependent loading

XIE Kanghe, WANG Kun, CHEN Guohong, HU Anfeng

期刊论文

Simplified analytical solution for free vibration characteristics of Hardfill dam

XIAO Wei, HE Yunlong, ZHANG Yanfeng

期刊论文

Experimental study for the stratified to slug flow regime transition mechanism of gas-oil two-phase flow in horizontal pipe

LIU Yiping, YANG Weilin, WANG Jing

期刊论文

Modeling and simulation of biomass air-steam gasification in a fluidized bed

KONG Xiaoying, WU Chuangzhi, YUAN Zhenhong, MA Longlong, CHANG Jie, LÜ Pengmei

期刊论文

A numerical study of helium-heated inorganic membrane reformer coupling to HTGR

YIN Huaqiang, JIANG Shengyao, JU Huaiming, ZHANG Youjie

期刊论文

Study on wave rotor refrigerators

Yuqiang DAI, Dapeng HU, Meixia DING

期刊论文

Lamb wave propagation modeling for structure health monitoring

Xiaoyue ZHANG, Shenfang YUAN, Tong HAO

期刊论文

工程科学领域的发展与现代物理学

宋文淼

期刊论文

Reliability assessment of three-dimensional bearing capacity of shallow foundation using fuzzy set theory

Rajarshi PRAMANIK, Dilip Kumar BAIDYA, Nirjhar DHANG

期刊论文

波粒二象性理论的若干问题

黄志洵

期刊论文

An Internet-of-Things Initiative for One Belt One Road (OBOR)

Li Da Xu

期刊论文

Responses to emerging and re-emerging infectious diseases: One world, One health

null

期刊论文