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Review of the crushing response of collapsible tubular structures

Vivek PATEL, Gaurav TIWARI, Ravikumar DUMPALA

《机械工程前沿（英文）》 2020年 第15卷 第3期   页码 438-474 doi: 10.1007/s11465-019-0579-1

摘要： Studies on determining and analyzing the crushing response of tubular structures are of significant interest, primarily due to their relation to safety. Several aspects of tubular structures, such as geometry, material, configuration, and hybrid structure, have been used as criteria for evaluation. In this review, a comprehensive analysis of the important findings of extensive research on understanding the crushing response of thin-walled tubular structures is presented. Advancements in thin-walled structures, including multi-cell tube, honeycomb and foam-filled, multi wall, and functionally graded thickness tubes, are also discussed, focusing on their energy absorption ability. An extensive review of experimentation and numerical analysis used to extract the deformation behavior of materials, such as aluminum and steel, against static and dynamic loadings are also provided. Several tube shapes, such as tubes of uniform and nonuniform (tapered) cross sections of circular, square, and rectangular shapes, have been used in different studies to identify their efficacy. Apart from geometric and loading parameters, the effects of fabrication process, heat treatment, and triggering mechanism on initiating plastic deformation, such as cutouts and grooves, on the surface of tubular structures are discussed.

关键词： monolithic structure     crashworthiness     energy absorber     static and dynamic loadings     multicellular tube structure     filled tube    

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Static behavior of planar intersecting CFST connection in diagrid structure

Ling LI, Xianzhong ZHAO, Ke KE

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 355-365 doi: 10.1007/s11709-011-0125-7

摘要： Intersecting connection plays an important role in the new diagrid structural system for high-rise buildings. To investigate the static behavior of the intersecting connection of concrete-filled steel tubular (CFST) columns, a typical reduced-scale planner connection specimen is tested under monotonic axial compression. The failure modes, force mechanism and bearing capacity of intersecting CFST connections are analyzed further in the follow-up numerical simulation, considering influences of intersecting angle, elliptical plate and ring plate. Test and simulation results prove that, intersecting connection can develop fully plastic deformation and provide sufficient bearing capacity. Parametric analysis indicates that bearing capacity of planar intersecting CFST connection mainly depends on intersecting angle and thickness of elliptical plate, while the ring plate affects that little. Capacity estimation method for planar intersecting CFST connection is proposed basing on the capacity of the critical section which is located near intersecting center for a distance of steel tube radius, and the design suggestions is provided in the end of this paper.

关键词： diagrid structure     concrete-filled steel tube     planar intersecting connection     experimental research     mechanism analysis    

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Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 606-624 doi: 10.1007/s11709-023-0925-6

摘要： A novel cambered surface steel tube damper (CSTD) with a cambered surface steel tube and two concave connecting plates is proposed herein. The steel tube is the main energy dissipation component and comprises a weakened segment in the middle, a transition segment, and an embedded segment. It is believed that during an earthquake, the middle weakened segment of the CSTD will be damaged, whereas the reliability of the end connection is ensured. Theoretical and experimental studies are conducted to verify the effectiveness of the proposed CSTD. Formulas for the initial stiffness and yield force of the CSTD are proposed. Subsequently, two CSTD specimens with different steel tube thicknesses are fabricated and tested under cyclic quasi-static loads. The result shows that the CSTD yields a stable hysteretic response and affords excellent energy dissipation. A parametric study is conducted to investigate the effects of the steel tube height, diameter, and thickness on the seismic performance of the CSTD. Compared with equal-stiffness design steel tube dampers, the CSTD exhibits better energy dissipation performance, more stable hysteretic response, and better uniformity in plastic deformation distributions.

关键词： cambered surface steel tube damper     energy dissipation capacity     finite element model     hysteretic performance     parametric study    

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Ginkgolide B against oxygen–glucose deprivation/reoxygenation and glucose injury in a new in vitro multicellular

null

《医学前沿（英文）》 2018年 第12卷 第3期   页码 307-318 doi: 10.1007/s11684-017-0547-2

摘要：

Acute ischemic stroke (AIS), as the third leading cause of death worldwide, is characterized by its high incidence, mortality rate, high incurred disability rate, and frequent reoccurrence. The neuroprotective effects of extract (GBE) against several cerebral diseases have been reported in previous studies, but the underlying mechanisms of action are still unclear. Using a novel rat cortical capillary endothelial cell-astrocyte-neuron network model, we investigated the neuroprotective effects of GBE and one of its important constituents, Ginkgolide B (GB), against oxygen–glucose deprivation/reoxygenation and glucose (OGD/R) injury. In this model, rat cortical capillary endothelial cells, astrocytes, and neurons were cocultured so that they could be synchronously observed in the same system. Pretreatment with GBE or GB increased the neuron cell viability, ameliorated cell injury, and inhibited the cell apoptotic rate through Bax and Bcl-2 expression regulation after OGD/R injury. Furthermore, GBE or GB pretreatment enhanced the transendothelial electrical resistance of capillary endothelial monolayers, reduced the endothelial permeability coefficients for sodium fluorescein (Na-F), and increased the expression levels of tight junction proteins, namely, ZO-1 and occludin, in endothelial cells. Results demonstrated the preventive effects of GBE on neuronal cell death and enhancement of the function of brain capillary endothelial monolayers after OGD/R injury ; thus, GBE could be used as an effective neuroprotective agent for AIS/reperfusion, with GB as one of its significant constituents.

关键词： acute ischemic stroke     Ginkgo bilobaextract     Ginkgolide B     network model     neuroprotection    

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Transversal tube pitch effects on local heat transfer characteristics of the flat tube bank fin mounted

Liangbi WANG, Zhimin LIN, Kangjie SUN, Yuanxin DONG, Song LIU, Yongheng ZHANG,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 333-345 doi: 10.1007/s11708-009-0061-6

摘要： The tube bank fin is commonly used to increase the area of the heat transfer surface with a small heat transfer coefficient of a heat exchanger. If vortex generators (VGs) are punched on the fin surface, the heat transfer performance of the fin can be improved. This paper focused on the effect of transversal tube pitch on the local heat transfer performance of the three-row flat tube bank fin mounted with VGs. On the fin surface, constructing the flow channel but without mounted VGs, the transversal tube pitch was greater, and the span averaged Nusselt number downstream was larger because fewer interactions of vortices would be generated from different VGs located upstream. When the area goodness factor was used as the criteria on the condition of one tube unit of heat exchanger for commonly used fin materials and fin thickness, the transversal tube pitch has considerable effect on the heat transfer enhancement of VGs. Large transversal tube pitch is more sensitive to fin material than to fin thickness.

关键词： heat transfer enhancement     vortex generator     finned flat tube bank     heat exchanger    

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交互式语音地球仪照明结构研究

郭阳宽,李颖晖,许玮,熊琦,马靖,王勇,宋宇

《中国工程科学》 2007年 第9卷 第5期   页码 50-52

摘要：

简述了交互式语音地球仪结构原理；研究了地球仪上首都的无歧义显示、发光二极管的布置以及首 都显示分辨率；制成了交互式语音地球仪。

关键词： 语音地球仪     结构设计     分辨率     束光筒     无歧义照明    

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Energy distribution between liquid hydrogen and liquid oxygen temperatures in a Stirling/pulse tube refrigerator

《能源前沿（英文）》 2023年 第17卷 第4期   页码 516-526 doi: 10.1007/s11708-022-0844-6

摘要： A two-stage gas-coupled Stirling/pulse tube refrigerator (SPR), whose first and second stages respectively involve Stirling and pulse tube refrigeration cycles, is a very promising spaceborne refrigerator. The SPR has many advantages, such as a compact structure, high reliability, and high performance, and is expected to become an essential refrigerator for space applications. In research regarding gas-coupled regenerative refrigerator, the energy flow distribution between the two stages, and optimal phase difference between the pressure wave and volume flow, are two critical parameters that could widely influence refrigerator performance. The effects of displacer displacement on the pressure wave, phase difference, acoustic power distribution, and inter-stage cooling capacity shift of the SPR have been investigated experimentally. Notably, to obtain the maximum first-stage cooling capacity, an inflection point in displacement exists. When the displacer displacement is larger than the inflection point, the cooling capacity could be distributed between the first and second stages. In the present study, an SPR was designed and manufactured to work between the liquid hydrogen and liquid oxygen temperatures, which can be used to cool small-scale zero boil-off systems and space detectors. Under appropriate displacer displacement, the SPR can reach a no-load cooling temperature of 15.4 K and obtain 2.6 W cooling capacity at 70 K plus 0.1 W cooling capacity at 20 K with 160 W compressor input electric power.

关键词： Stirling/pulse tube refrigerator     displacer displacement     space application     phase shift     energy distribution    

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Genetic evidence in planar cell polarity signaling pathway in human neural tube defects

null

《医学前沿（英文）》 2014年 第8卷 第1期   页码 68-78 doi: 10.1007/s11684-014-0308-4

摘要：

Neural tube defects (NTDs) are a group of birth anomalies having a profound physical, emotional, and financial effects on families and communities. Their etiology is complex, involving environmental and genetic factors that interact to modulate the incidence and severity of the developing phenotype. The planar cell polarity (PCP) pathway controls the process of convergent extension (CE) during gastrulation and neural tube closure and has been implicated in the pathogenesis of NTDs in animal models and human cohorts. This review summarizes the cumulative results of recent studies on PCP signaling pathway and human NTDs. These results demonstrate that PCP gene alterations contribute to the etiology of human NTDs.

关键词： planar cell polarity     neural tube defects     rare mutations    

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Experimental and statistical investigation of a new concrete-composite beam with encased polymer tube

Abdelmadjid SI SALEM,Souad AIT TALEB,Kamal AIT TAHAR

《结构与土木工程前沿（英文）》 2015年 第9卷 第2期   页码 154-162 doi: 10.1007/s11709-015-0296-8

摘要： A new concrete-composite beam with high mechanical performances to weight ratio is developed in this study. The proposed design technique consists to embed a cylindrical polymer tube wrapped by a GFRP Jacket in the mechanically ineffective concrete tensile zone. An experimental investigation is carried out on composite beams under bending loads until failure to evaluate the flexural capacity and the corresponding failure mechanisms. Based on the experimental results, statistical and preliminary reliability analyses using the FORM method are performed to assess the safety margin of the new beam. The confrontation between test and simulation results shows a satisfactory agreement, and represents a promising revelation regarding the improvement in terms of strength and ductility of such design compared to conventional reinforced concrete beams with traditional one.

关键词： design     GFRP-Jacket     polymer tube     test     reliability analysis    

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Thermal-hydraulic performance of novel louvered fin using flat tube cross-flow heat exchanger

DONG Junqi, CHEN Jiangping, CHEN Zhijiu

《能源前沿（英文）》 2008年 第2卷 第1期   页码 99-106 doi: 10.1007/s11708-008-0010-9

摘要： Experimental studies were conducted to investigate the air-side heat transfer and pressure drop characteristics of a novel louvered fins and flat tube heat exchangers. A series of tests were conducted for 9 heat exchangers with different fin space and fin length, at a constant tube-side water flow rate of 2.8 m/h. The air side thermal performance data were analyzed using the effectiveness-NTU method. Results were presented as plot of Colburn factor and friction factor against the Reynolds number in the range of 500–6500. The characteristics of the heat transfer and pressure drop of different fin space and fin length were analyzed and compared. In addition, the curves of the heat transfer coefficients vs. pumping power per unit heat transfer area were plotted. Finally, the area optimization factor was used to evaluate the thermal hydraulic performance of the louvered fins with differential geometries. The results showed that the and factors increase with the decrease of the fin space and fin length, and the fin space has more obvious effect on the thermal hydraulic characteristics of the novel louvered fins.

关键词： obvious effect     different     thermal hydraulic     constant tube-side     Colburn    

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adsorption onto a niobium wire for electrothermal atomization atomic absorption spectrometry with a tungsten tube

Satoshi KANECO, Hiroaki KITANAGA, Hideyuki KATSUMATA, Tohru SUZUKI

《化学科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 432-435 doi: 10.1007/s11705-012-1219-z

摘要： In the present work, a new preconcentration method of trace elements by adsorption onto a niobium wire has been developed for electrothermal atomization atomic absorption spectrometry (ETAAS) with a tungsten tube atomizer. Detection limits (pg·mL ) by this method combined with ETAAS were 45 for bismuth, 7.0 for cadmium, 20 for copper, 1.3 for gold, 36 for lead, 65 for manganese, 9.5 for rhodium and 19 for silver.

关键词： preconcentration     adsorption onto niobium wire     electrothermal atomization atomic absorption spectrometry     tungsten tube atomizer     trace elements    

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Calculation and analysis of sub/supercritical methanol preheating tube for continuous production of biodiesel

Wen CHEN, Weiyong YING, Cunwen WANG, Weiguo WANG, Yuanxin WU, Junfeng ZHANG,

《能源前沿（英文）》 2009年 第3卷 第4期   页码 423-431 doi: 10.1007/s11708-009-0075-0

摘要： Biodiesel is an important renewable energy. Supercritical methanol transesterification for biodiesel has recently been concerned because of its obvious advantages. The tubular reactor is an ideal reactor for continuous preparation of biodiesel via supercritical methanol transesterification. A methanol preheating tube is necessary for the tubular reaction system because the reaction temperature for supercritical methanol transesterification is usually 520―600K. Therefore, in the range of 298―600K, changes of the density, isobaric capacity, viscosity and thermal conductivity of sub/supercritical methanol with temperature are first discussed. Then on the basis of these thermophysical properties, an integration method is adopted for the design of sub/supercritical methanol preheating tube when methanol is preheated from 298K to 600K at 16MPa and the influencing factors on the length of the preheating tube are also studied. The computational results show that the Reynolds number and the local convection heat-transfer coefficient of sub/supercritical methanol flowing in ф6mm×1.5mm preheating tube change drastically with temperature. For the local overall heat transfer coefficient and the average overall heat transfer coefficient , temperature also has an important influence on them when the inlet velocity of methanol is lower than 0.5m/s. But when the inlet velocity of methanol is higher than 0.5m/s, and almost keep invariable with temperature. Additionally, both the outlet temperature and the inlet velocity of methanol are the key affecting factors for the length of the preheating tube, especially when the outlet temperature is over the critical temperature of methanol. At the same time, the increase of tin bath’s temperature can shorten the required length of the preheating tube. At the inlet flow rate of 0.5m/s, the required length of the preheating tube is 2.0m when methanol is preheated from 298K to 590K at 16MPa with keeping the tin bath’s temperature 620K, which is in good agreement with the experimental results.

关键词： sub/supercritical methanol     preheating tube     integration method     biodiesel    

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Optimization of Venturi tube design for pipeline pulverized coal flow measurements

WU Zhansong, XIE Fei

《能源前沿（英文）》 2008年 第2卷 第4期   页码 369-373 doi: 10.1007/s11708-008-0072-8

摘要： A Venturi flow meter was designed to accurately measure the mass flow rate of pulverized coal in power plant pipelines. Numerical simulations of the dilute turbulent gas-solid two-phase flow in a horizontal Venturi tube were used to study the effects of Venturi tube geometry on the pressure distribution in the mixture. The results show that Venturi tube geometry strongly influences the metering of the dilute gas-particle two-phase flow. The geometry can be optimized to improve the precision of the measurement and ensure stable measurements. Furthermore, the geometries of three types of Venturi tubes were optimized for an experimental study of pulverized coal mass flow rate measurements.

关键词： gas-solid two-phase     geometry     gas-particle two-phase     Numerical     flow    

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Experimental study on film combustion formed by spirally fluted horizontal tube

MEI Ning, ZHANG Bin, ZHAO Jian, ZHANG Ming

《能源前沿（英文）》 2008年 第2卷 第1期   页码 54-58 doi: 10.1007/s11708-008-0023-4

摘要： Falling fuel film on the spirally fluted surface of a horizontal tube can provide rapid fuel evaporation and homogeneous mixture formation. This fuel film combustion could be applied in a micro-combustion system even without a fuel pump. A test bed was established and experimental comparisons were made between the prototype and a transferred cup atomizer micro-combustor. The theoretical and experimental results show that film combustion has a higher combustion efficiency, a lower pollutant emission and a better working performance.

关键词： homogeneous     transferred     evaporation     micro-combustion     efficiency    

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Experiment study of a quartz tube falling particle receiver

Tianjian WANG, Fengwu BAI, Shunzhou CHU, Xiliang ZHANG, Zhifeng WANG

《能源前沿（英文）》 2017年 第11卷 第4期   页码 472-479 doi: 10.1007/s11708-017-0502-6

摘要： This paper presents an experimental evaluation of a specially designed falling particle receiver. A quartz tube was used in the design, with which the particles would not be blown away by wind. Concentrated solar radiation was absorbed and converted into thermal energy by the solid particles flowed inside the quartz tube. Several experiments were conducted to test the dynamic thermal performance of the receiver on solar furnace system. During the experiments, the maximum particle temperature rise is 212°C, with an efficiency of 61.2%, which shows a good thermal performance with a falling distance of 0.2 m in a small scale particle receiver. The average outlet particle temperature is affected by direct normal irradiance (DNI) and other factors such as wind speed. The solid particles obtain a larger viscosity with a higher temperature while smaller solid particles are easier to get stuck in the helix quartz tube. The heat capacity of the silicon carbide gets larger with the rise of particle temperature, because as the temperature of solid particles increases, the temperature rise of the silicon carbide decreases.

关键词： solar thermal electricity     central receiver     particle receiver     experimental research    

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标题 作者 时间 类型 操作

Review of the crushing response of collapsible tubular structures

Vivek PATEL, Gaurav TIWARI, Ravikumar DUMPALA

期刊论文

Static behavior of planar intersecting CFST connection in diagrid structure

Ling LI, Xianzhong ZHAO, Ke KE

期刊论文

Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

期刊论文

Ginkgolide B against oxygen–glucose deprivation/reoxygenation and glucose injury in a new in vitro multicellular

null

期刊论文

Transversal tube pitch effects on local heat transfer characteristics of the flat tube bank fin mounted

Liangbi WANG, Zhimin LIN, Kangjie SUN, Yuanxin DONG, Song LIU, Yongheng ZHANG,

期刊论文

交互式语音地球仪照明结构研究

郭阳宽,李颖晖,许玮,熊琦,马靖,王勇,宋宇

期刊论文

Energy distribution between liquid hydrogen and liquid oxygen temperatures in a Stirling/pulse tube refrigerator

期刊论文

Genetic evidence in planar cell polarity signaling pathway in human neural tube defects

null

期刊论文

Experimental and statistical investigation of a new concrete-composite beam with encased polymer tube

Abdelmadjid SI SALEM,Souad AIT TALEB,Kamal AIT TAHAR

期刊论文

Thermal-hydraulic performance of novel louvered fin using flat tube cross-flow heat exchanger

DONG Junqi, CHEN Jiangping, CHEN Zhijiu

期刊论文

adsorption onto a niobium wire for electrothermal atomization atomic absorption spectrometry with a tungsten tube

Satoshi KANECO, Hiroaki KITANAGA, Hideyuki KATSUMATA, Tohru SUZUKI

期刊论文

Calculation and analysis of sub/supercritical methanol preheating tube for continuous production of biodiesel

Wen CHEN, Weiyong YING, Cunwen WANG, Weiguo WANG, Yuanxin WU, Junfeng ZHANG,

期刊论文

Optimization of Venturi tube design for pipeline pulverized coal flow measurements

WU Zhansong, XIE Fei

期刊论文

Experimental study on film combustion formed by spirally fluted horizontal tube

MEI Ning, ZHANG Bin, ZHAO Jian, ZHANG Ming

期刊论文

Experiment study of a quartz tube falling particle receiver

Tianjian WANG, Fengwu BAI, Shunzhou CHU, Xiliang ZHANG, Zhifeng WANG

期刊论文