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关键词

波粒二象性 3

超光速 3

临界风速 2

快子 2

消失波 2

烟颗粒 2

狭义相对论 2

相对论 2

粒子群优化 2

粒子群优化算法 2

300 M钢 1

ADV 1

Chebyshev多项式 1

EFP 1

Fe、Co、Ru 碳化物 1

GH位移 1

Hilare 机器人 1

Maxwell方程组 1

PIV 1

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High velocity impact of metal sphere on thin metallic plate using smooth particle hydrodynamics (SPH)

Hossein ASADI KALAMEH, Arash KARAMALI, Cosmin ANITESCU, Timon RABCZUK

《结构与土木工程前沿(英文)》 2012年 第6卷 第2期   页码 101-110 doi: 10.1007/s11709-012-0160-z

摘要: The modeling of high velocity impact is an important topic in impact engineering. Due to various constraints, experimental data are extremely limited. Therefore, detailed numerical simulation can be considered as a desirable alternative. However, the physical processes involved in the impact are very sophisticated; hence a practical and complete reproduction of the phenomena involves complicated numerical models. In this paper, we present a smoothed particle hydrodynamics (SPH) method to model two-dimensional impact of metal sphere on thin metallic plate. The simulations are applied to different materials (Aluminum, Lead and Steel); however the target and projectile are formed of similar metals. A wide range of velocities (300, 1000, 2000, and 3100 m/s) are considered in this study. The goal is to study the most sensitive input parameters (impact velocity and plate thickness) on the longitudinal extension of the projectile, penetration depth and damage crater.

关键词: smoothed particle hydrodynamics     high velocity impact     sensitivity analysis    

Characterization of particle deposition during crossflow filtration as influenced by permeate flux andcrossflow velocity using a microfluidic filtration system

Hongzhan Di, Gregory J. O. Martin, Dave E. Dunstan

《化学科学与工程前沿(英文)》 2021年 第15卷 第3期   页码 552-561 doi: 10.1007/s11705-020-1962-5

摘要: Particle deposition during crossflow filtration is significantly influenced by the operating conditions, in particular the permeate flux and crossflow velocity. However, there is a lack of detailed knowledge about how deposit layer structures and distributions depend on operating parameters. This study uses a microfluidic visualisation filtration system to examine the influence of operating conditions on the deposition process during crossflow ultrafiltration from a microscopic perspective. Increasing the permeate flux caused an increasing amount of deposition and a thicker deposit layer. Higher crossflow velocities reduced the extent of deposition. The degree of deposition varied over a range of operating conditions due to the altered hydrodynamic forces exerted on the particles, which can be examined by the deposition probability according to an existing model. Building on this, an empirical correlation between the deposition probability and volume of deposition as function of filtration time was developed, which gave good agreement with experimental results. The effect of solution conditions was also involved in this correlation as a interaction energies. This could be useful for predicting the dynamic deposition process during crossflow filtration over a range of operating and solution conditions.

关键词: particle deposition     crossflow filtration     microfluidics     confocal microscopy    

Response surface regression analysis on FeCrBSi particle in-flight properties by plasma spray

Runbo MA,Lihong DONG,Haidou WANG,Shuying CHEN,Zhiguo XING

《机械工程前沿(英文)》 2016年 第11卷 第3期   页码 250-257 doi: 10.1007/s11465-016-0401-2

摘要:

This work discusses the interactive effects between every two of argon flow rate, voltage, and spray distance on in-flight particles by plasma spray and constructs models that can be used in predicting and analyzing average velocity and temperature. Results of the response surface methodology show that the interactive effects between voltage and spray distance on particle in-flight properties are significant. For a given argon flow rate, particle velocity and temperature response surface are obviously bending, and a saddle point exists. With an increase in spray distance, the interactive effects between voltage and argon flow rate on particle in-flight properties appear gradually and then weaken. With an increase in voltage, the interactive effects between spray distance and argon flow rate on particle in-flight properties change from appearing to strengthening and then to weakening.

关键词: particle velocity     particle temperature     interactive effects     response surface    

Discrete element method modeling of corn-shaped particle flow in rectangular hopper

He TAO, Baosheng JIN, Wenqi ZHONG, Xiaofang WANG,

《结构与土木工程前沿(英文)》 2010年 第4卷 第2期   页码 267-275 doi: 10.1007/s11709-010-0035-0

摘要: Discrete element method (DEM) was developed to simulate the corn-shaped particles flow in the hopper. The corn-shaped particle was described by four overlapping spheres. Contact force and gravity force were considered when establishing the model. In addition, flowing characteristic of particles in the hopper was studied. The effect of friction coefficient on the wall pressure, voidage and velocity distribution was analyzed. The results show that the discharge rate decreases with the friction coefficient increasing; and the “over-pressure” phenomenon occurs in the discharging process for two different friction coefficients. The voidage also increases as the friction coefficient increasing. And the velocity distribution is more uniformity and is closer to the mass flow with the friction coefficient deceasing.

关键词: discrete         element          method         (DEM)             non-spherical     voidage     pressure     velocity distribution     hopper    

气流速度对感烟火灾探测器响应灵敏度的影响

谢启源,苏国锋,袁宏永,张永明

《中国工程科学》 2005年 第7卷 第11期   页码 76-80

摘要:

针对地下车库、空调出风口等存在高速气流的特殊场所,利用火灾探测综合模拟实验平台,根据气流是否影响烟颗粒生成过程,分别设计2种实验方案,分析比较了光电型与离子型两种感烟火灾探测器在不同气流条件下的响应灵敏度。实验结果表明,在烟颗粒生成过程不受气流影响的情况下,两种感烟探测器的响应灵敏度均随气流速度增大而下降。在气流影响烟颗粒生成过程的情况下,光电感烟探测器的灵敏度依然随着气流速度的增大而迅速下降;而离子型感烟探测器的灵敏度受气流速度影响较小,在高速气流条件下依然保持较高的灵敏度。综合分析表明,离子感烟探测器较适合在高速气流环境中工作。

关键词: 气流速度     感烟火灾探测器     烟颗粒     粒径分布    

Prediction of the shear wave velocity

Amoroso SARA

《结构与土木工程前沿(英文)》 2014年 第8卷 第1期   页码 83-92 doi: 10.1007/s11709-013-0234-6

摘要: The paper examines the correlations to obtain rough estimates of the shear wave velocity from non-seismic dilatometer tests (DMT) and cone penetration tests (CPT). While the direct measurement of is obviously preferable, these correlations may turn out useful in various circumstances. The experimental results at six international research sites suggest that the DMT predictions of from the parameters (material index), (horizontal stress index), (constrained modulus) are more reliable and consistent than the CPT predictions from (cone resistance), presumably because of the availability, by DMT, of the stress history index .

关键词: horizontal stress index     shear wave velocity     flat dilatometer test     cone penetration test    

速度约束条件下基于步进电机驱动的Hilare 机器人航点导航的控制 Article

Robins Mathew,Somashekhar S. Hiremath

《工程(英文)》 2018年 第4卷 第4期   页码 491-499 doi: 10.1016/j.eng.2018.07.013

摘要: 本文利用多目标粒子群优化(multi-objective particle swarm optimization, MOPSO)的方法来调整控制器的参数。

关键词: 轨迹跟踪     自适应控制     航点导航     Hilare 机器人     粒子群优化     随机路图    

Experimental study on velocity characteristics of recirculation zone in humid air non-premixed flame

GU Xin, ZANG Shusheng, GE Bing

《能源前沿(英文)》 2008年 第2卷 第2期   页码 140-144 doi: 10.1007/s11708-008-0037-y

摘要: To examine the effect of the flow field within the recirculation zone on flame structure, the characteristic velocity fields of methane/humid air flame in non-premixed combustion behind a disc bluff-body burner were experimentally studied by particle image velocimeter (PIV).The results show that two stagnation points exist on the centerline in the recirculation zone flame. However, the distance of the two stagnation points in humid air combustion shortens, and the minimal dimensionless velocity increases compared with the conventional non-humid air combustion. In addition, the positional curves of the minimal velocities can be partitioned into three phases representing three different flame patterns. The analysis of axial minimal velocities on the centerline and their positions under different co-flow air velocity conditions reveals that fuel-to-air velocity ratio is the crucial parameter that governs humid air combustion flame characteristics.

关键词: distance     bluff-body     fuel-to-air velocity     stagnation     parameter    

definition of metabolic dysfunction-associated fatty liver disease with elevated brachial-ankle pulse wave velocity

《医学前沿(英文)》 2022年 第16卷 第5期   页码 714-722 doi: 10.1007/s11684-021-0888-8

摘要: A new definition of metabolic dysfunction-associated fatty liver disease (MAFLD) has recently been proposed. We aim to examine the associations of MAFLD, particularly its discordance from non-alcoholic fatty liver disease (NAFLD), with the progression of elevated brachial-ankle pulse wave velocity (baPWV) and albuminuria in a community-based study sample in Shanghai, China. After 4.3 years of follow-up, 778 participants developed elevated baPWV and 499 developed albuminuria. In comparison with the non-MAFLD group, the multivariable adjusted odds ratio (OR) of MAFLD group for new-onset elevated baPWV was 1.25 (95% confidence interval (CI) 1.01–1.55) and 1.35 (95% CI 1.07–1.70) for albuminuria. Participants without NAFLD but diagnosed according to MAFLD definition were associated with higher risk of incident albuminuria (OR 1.77; 95% CI 1.07–2.94). Patients with MAFLD with high value of hepamet fibrosis score or poor-controlled diabetes had higher risk of elevated baPWV or albuminuria. In conclusion, MAFLD was associated with new-onset elevated baPWV and albuminuria independently of body mass index, waist circumference, and hip circumference. Individuals without NAFLD but diagnosed as MAFLD had high risk of albuminuria, supporting that MAFLD criteria would be practical for the evaluation of long-term risk of subclinical atherosclerosis among fatty liver patients.

关键词: metabolic dysfunction-associated fatty liver disease     non-alcoholic fatty liver disease     fibrosis score     brachial-ankle pulse wave velocity     albuminuria    

Catalyst particle shapes and pore structure engineering for hydrodesulfurization and hydrodenitrogenation

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 897-908 doi: 10.1007/s11705-021-2127-x

摘要: Catalyst particle shapes and pore structure engineering are crucial for alleviating internal diffusion limitations in the hydrodesulfurization (HDS)/hydrodenitrogenation (HDN) of gas oil. The effects of catalyst particle shapes (sphere, cylinder, trilobe, and tetralobe) and pore structures (pore diameter and porosity) on HDS/HDN performance at the particle scale are investigated via mathematical modeling. The relationship between particle shape and effectiveness factor is first established, and the specific surface areas of different catalyst particles show a positive correlation with the average HDS/HDN reaction rates. The catalyst particle shapes primarily alter the average HDS/HDN reaction rate to adjust the HDS/HDN effectiveness factor. An optimal average HDS/HDN reaction rate exists as the catalyst pore diameter and porosity increase, and this optimum value indicates a tradeoff between diffusion and reaction. In contrast to catalyst particle shapes, the catalyst pore diameter and the porosity of catalyst particles primarily alter the surface HDS/HDN reaction rate to adjust the HDS/HDN effectiveness factor. This study provides insights into the engineering of catalyst particle shapes and pore structures for improving HDS/HDN catalyst particle efficiency.

关键词: hydrodesulfurization     hydrodenitrogenation     particle shape     pore structure    

A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

《能源前沿(英文)》 2012年 第6卷 第1期   页码 89-97 doi: 10.1007/s11708-012-0176-z

摘要: This paper discusses two problems in in-line particle sizing when using light fluctuation method. First, by retrieving the ratio of particle concentrations at different time, the intensity of incident light is obtained. There exists narrow error between the calculated and pre-detected value of the intensity of incident light. Secondly, by combining spectrum analysis with Gregory’s theory, a multi-sub-size zone model is proposed, with which the relationship between the distribution of turbidity and the particle size distribution (PSD) can be established, and an algorithm developed to determine the distribution of turbidity. Experiments conducted in the laboratory indicate that the measured size distribution of pulverized coal conforms well with the imaging result.

关键词: in-line measurement     particle size distribution (PSD)     incident light intensity     particle concentration     light fluctuation    

Theoretical study of failure in composite pressure vessels subjected to low-velocity impact and internal

Roham RAFIEE, Hossein RASHEDI, Shiva REZAEE

《结构与土木工程前沿(英文)》 2020年 第14卷 第6期   页码 1349-1358 doi: 10.1007/s11709-020-0650-3

摘要: A theoretical solution is aimed to be developed in this research for predicting the failure in internally pressurized composite pressure vessels exposed to low-velocity impact. Both in-plane and out-of-plane failure modes are taken into account simultaneously and thus all components of the stress and strain fields are derived. For this purpose, layer-wise theory is employed in a composite cylinder under internal pressure and low-velocity impact. Obtained stress/strain components are fed into appropriate failure criteria for investigating the occurrence of failure. In case of experiencing any in-plane failure mode, the evolution of damage is modeled using progressive damage modeling in the context of continuum damage mechanics. Namely, mechanical properties of failed ply are degraded and stress analysis is performed on the updated status of the model. In the event of delamination occurrence, the solution is terminated. The obtained results are validated with available experimental observations in open literature. It is observed that the sequence of in-plane failure and delamination varies by increasing the impact energy.

关键词: composite pressure vessel     low-velocity impact     failure     theoretical solution     progressive damage modeling    

Independent cover meshless particle method for complex geotechnical engineering

Jianqiu WU, Yongchang CAI

《结构与土木工程前沿(英文)》 2018年 第12卷 第4期   页码 515-526 doi: 10.1007/s11709-017-0428-4

摘要: A new Independent Cover Meshless Particle (ICMP) method is proposed for the analysis of complex geotechnical engineering. In the ICMP method, the independent rectangular cover regardless of the shape of the analysis model is employed as the influence domain of each discrete node, the general polynomial is employed as the meshless interpolation function of the independent nodal cover, and the Cartesian Transformation Method (CTM) is used for the numerical integration of the nodal covers cut by material interfaces, joints, cracks and faults. The present method has a simple formulation and a low computational cost, and is easy for the numerical analysis and modeling of complex geotechnical engineering. Several typical numerical examples are presented to demonstrate the accuracy and robustness of the proposed method.

关键词: meshless method     particle method     independent cover     CTM     geotechnical engineering    

Microdamage study of granite under thermomechanical coupling based on the particle flow code

《结构与土木工程前沿(英文)》   页码 1413-1427 doi: 10.1007/s11709-023-0953-2

摘要: The thermomechanical coupling of rocks refers to the interaction between the mechanical and thermodynamic behaviors of rocks induced by temperature changes. The study of this coupling interaction is essential for understanding the mechanical and thermodynamic properties of the surrounding rocks in underground engineering. In this study, an improved temperature-dependent linear parallel bond model is introduced under the framework of a particle flow simulation. A series of numerical thermomechanical coupling tests are then conducted to calibrate the micro-parameters of the proposed model by considering the mechanical behavior of the rock under different thermomechanical loadings. Good agreement between the numerical results and experimental data are obtained, particularly in terms of the compression, tension, and elastic responses of granite. With this improved model, the thermodynamic response and underlying cracking behavior of a deep-buried tunnel under different thermal loading conditions are investigated and discussed in detail.

关键词: thermomechanical coupling effect     granite     improved linear parallel bond model     thermal property     particle flow code    

Study on direct measurement method of vorticity from particle images

RUAN Xiaodong, FU Xin, YANG Huayong

《能源前沿(英文)》 2007年 第1卷 第4期   页码 408-412 doi: 10.1007/s11708-007-0059-1

摘要: To overcome the shortcomings of conventional methods for vorticity measurement, a new direct measurement of vorticity (DMV) method extracting vorticity from particle images was proposed. Based on the theory of fluid flow, two matc

关键词: conventional     vorticity measurement     particle     DMV     theory    

标题 作者 时间 类型 操作

High velocity impact of metal sphere on thin metallic plate using smooth particle hydrodynamics (SPH)

Hossein ASADI KALAMEH, Arash KARAMALI, Cosmin ANITESCU, Timon RABCZUK

期刊论文

Characterization of particle deposition during crossflow filtration as influenced by permeate flux andcrossflow velocity using a microfluidic filtration system

Hongzhan Di, Gregory J. O. Martin, Dave E. Dunstan

期刊论文

Response surface regression analysis on FeCrBSi particle in-flight properties by plasma spray

Runbo MA,Lihong DONG,Haidou WANG,Shuying CHEN,Zhiguo XING

期刊论文

Discrete element method modeling of corn-shaped particle flow in rectangular hopper

He TAO, Baosheng JIN, Wenqi ZHONG, Xiaofang WANG,

期刊论文

气流速度对感烟火灾探测器响应灵敏度的影响

谢启源,苏国锋,袁宏永,张永明

期刊论文

Prediction of the shear wave velocity

Amoroso SARA

期刊论文

速度约束条件下基于步进电机驱动的Hilare 机器人航点导航的控制

Robins Mathew,Somashekhar S. Hiremath

期刊论文

Experimental study on velocity characteristics of recirculation zone in humid air non-premixed flame

GU Xin, ZANG Shusheng, GE Bing

期刊论文

definition of metabolic dysfunction-associated fatty liver disease with elevated brachial-ankle pulse wave velocity

期刊论文

Catalyst particle shapes and pore structure engineering for hydrodesulfurization and hydrodenitrogenation

期刊论文

A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

期刊论文

Theoretical study of failure in composite pressure vessels subjected to low-velocity impact and internal

Roham RAFIEE, Hossein RASHEDI, Shiva REZAEE

期刊论文

Independent cover meshless particle method for complex geotechnical engineering

Jianqiu WU, Yongchang CAI

期刊论文

Microdamage study of granite under thermomechanical coupling based on the particle flow code

期刊论文

Study on direct measurement method of vorticity from particle images

RUAN Xiaodong, FU Xin, YANG Huayong

期刊论文