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Bubbling behavior of cohesive particles in a two-dimensional fluidized bed with immersed tubes

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Particuology 2017年第2期15卷 152-160页

作者： Jiliang Ma Daoyin Liu Xiaoping Chen Key Laboratory of Energy Thermal Conversion and Control of Ministry of Educotion School of Energy and Environment Southeast University Nanjing 210096 China

Fluidization hydrodynamics are greatly influenced by inter-particle cohesive forces. This paper studies the fluidization of large cohesive particles in a two-dimensional fluidized bed with immersed tubes using “polymer coating” to introduce cohesive force, to gain better understanding of bubbling behavior when particles become cohesive and its effect on chemical processes. The results show that the cohesive force promotes bubble splitting in the tube bank region, thereby causing an increase in the number and a decline in the aspect ratio of the bubbles. As the cohesive force increases within a low level, the bubble number increases and the bubble diameter decreases, while the aspect ratio exhibits different trends at different fluidization gas velocities. The difference in the evolution of bubble size under various cohesive forces mainly takes place in the region without tubes. When the cohesive force is large enough to generate stable agglomerates on the side walls of the bed, the bubble number and the bed expansion sharply decrease. The tubes serve as a framework that promotes the agglomeration, thus accelerating defluidization. Finally, the bubble profile around tubes was studied and found to greatly depend both on the cohesive forces and the location of tubes.

关键词： Fluidized bed Cohesive particle Immersed tube Bubble behavior

Portable device for the local three-dimensional deformation measurement using a single camera

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science China(Technological sciences) 2018年第1期61卷 51-60页

作者： MOHAMMED Mokhtar Eisa SHAO XinXing HE XiaoYuan School of Civil Engineering Department of Engineering Mechanics Southeast University

The aim of this paper is to establish and validate a portable device for the local three dimensional deformation measurements using a single camera combined with a triangular prism mirror and two mirrors. The mirrors were utilized to convert a single camera into a stereo image system, which views a test object from two different directions and records the surface images of the test specimen on the two halves of the camera sensor in order to achieve a three-dimensional measurement. The proposed system consists of a single camera and the reflection system was integrated into a portable device to achieve a truly portable, low-cost, local three-dimensional deformation measurement, one-time calibration and easy implementation in situ. The optical design and measurement procedures to obtain the three-dimensional （3D） deformation measurements of the proposed system were described in detail. The efficiency and precision of the proposed system were verified by measuring the displacements of a translated fiat plate. As a practical application, the proposed system is used to measure the out-of-plane displacement of an aluminum circular plate with a central load. Moreover, the normal strain measurement of a plastic beam under symmetric four-point bending via an outer loading frame was also presented. The measurement results are in good accordance with the data obtained by strain gauges. The experimental results revealed that the proposed system was practicable and effective for the local three-dimensional deformation measurement. This system well-suited to both laboratory and field condition and will have significant application in the fields of engineering.

关键词： digital image correlation single camera strain analysis local 3D deformation

Spatial and Excitation Variations for Different Applied Voltages in an Atmospheric Neon Plasma Jet

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Plasma science and Technology 2016年第9期18卷 912-917页

作者：杨兰兰屠彦俞永波户玎岚张雄 School of Electronic science and Engineering Southeast University

A neon plasma jet was generated in air, driven by a 9 kHz sinusoidal power supply. The characteristics of the plasma plume and the optical spectra with plasma propagation for different applied voltages were investigated. By increasing the applied voltage, the plasma plume first increases and then retracts to become short and bulky. The shortened effect of Ne plasma plume （about 10 mm） for the further voltage increasing is more apparent than that of He （about 3 mm） and Ar （about 1 mm）. Emission intensity of the N2 （337 am） increases with the applied voltage, gradually substituting the emission intensity of Ne （702 nm and 585 am） as the noticeable radiation. At the nozzle opening, the Ne （702 am） emission dominates, while the Ne （585 nm） emission is most noticeable around the tip of the plasma plume. The spatial distribution of the three spectral lines indicates that Ne （702 nm） emission decreases dramatically with plasma propagation while Ne （585 am） and N2 （337 nm） emissions reach their maxima at the middle of the plasma plume. The results indicate that the Ne （702 nm） emission is much more sensitive to the average electron temperature and the density of the high-energy electrons, so it changes greatly at the tube nozzle and little at the tip region as the voltage increases. The population of high-energy electrons, the average electron temperature, the collision with air molecules and the Penning effect between Ne metastables and air molecules may explain their different variations with plasma propagating and voltage increasing.

关键词： neon plasma jet optical spectrum plasma plume emission variation

Eutectic Solidification in Al-13.0%Si Alloys with Combined Addition of Strontium and Boron

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Journal of Materials science & Technology 2009年第4期25卷 437-440页

作者： Hengcheng Liao,Ke Ding,Juanjuan Bi,Min Zhang,Huipin Wang and Lei Zhao School of Materials science and Engineering,southeast university,Nanjing 211198,China Jiangsu Key Laboratory for Advanced Metallic Materials,Nanjing 211189,China SE Univ Sch Mat Sci & Engn Nanjing 211198 Peoples R China

The influence of addition of boron （B） on eutectic solidification in a near-eutectic Al-13.0%Si alloy modified with strontium （Sr） was investigated using thermal analysis and macro/microstructure observation. Addition of B in the Sr-modified alloy leads to a considerable increase in nucleation temperature （TN, the minimum temperature prior to recalescence （TM） and growth temperature （To）. In the Sr-modified alloy, nucleation of eutectic might originate at the heterogeneous sites on the mold wall or in the melt near the wall, and eutectic solidification proceeds gradually towards the center, controlled by undercooling of melt. However, with addition of B in the Sr-modified alloy, undercooling required for eutectic nucleation became small, and hence eutectic solidification might occur almost simultaneously within whole casting, controlled by amount of heterogeneous sites. With excessive addition of B in the Sr-modified alloy, nucleation of eutectic grains was explosive within the whole casting and the power of Sr on eutectic solidification was completely poisoned.

关键词： Al-Si alloys Solidification Microstructure Thermal analysis

A four-channel microelectronic system for neural signal regeneration

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Journal of Semiconductors 2009年第12期30卷 81-86页

作者：谢书珊王志功吕晓迎李文渊潘海仙 Institute of RF-& OE-ICs Southeast University State Key Laboratory of Bio-Electronics Southeast University

This paper presents a microelectronic system which is capable of making a signal record and functional electric stimulation of an injured spinal cord. As a requirement of implantable engineering for the regeneration microelectronic system, the system is of low noise, low power, small size and high performance. A front-end circuit and two high performance OPAs （operational amplifiers） have been designed for the system with different functions, and the two OPAs are a low-noise low-power two-stage OPA and a constant-gm RTR input and output OPA. The system has been realized in CSMC 0.5-μm CMOS technology. The test results show that the system satisfies the demands of neuron signal regeneration.

关键词： implanted neuronal signal regeneration detecting stimulating

Model and Simulation of a New Ultra-Narrow Trigger Frequency Alterable Pulse Generator

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Journal of Shanghai Jiaotong university(science) 2011年第6期16卷 687-690页

作者：杨运峰曹振新叶展窦文斌苏宏艳 State Key Laboratory of Millimeter Waves Southeast University National Key Laboratory of Millimeter Wave System

Two new kinds of ultra-narrow trigger frequency alterable picosecond pulse generator are *** can produce positive pulses and the other can produce negative *** two pulse generators are subdivided into three parts:signal driving circuit,differentiator network and pulse shaping *** pulse shaping circuit is made of step recovery diode(SRD) and short-circuit microstrip line.A positive pulse with width of 54 ps(50%-50%),rising time of 30 ps(10%-90%) and falling time of 32 ps(90%-10%),and a negative pulse with width of 54 ps(50%-50%),rising time of 30 ps(90%-10%) and falling time of 30 ps(10%-90%) are achieved in *** of the components are ready-made and *** can be applied in ultra-wideband(UWB) communication system,such as transmitters and receivers.

关键词： pulse generator ultra-narrow step recovery diode(SRD) pulse shaping circuit

Electrochemical,thermal,and photophysical properties of novel two-photon absorption chromophores

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Chinese Optics Letters 2009年第6期7卷 521-523页

作者：钱鹰张勤勤孟康黄维吕昌贵崔一平 School of Chemistry and Chemical Engineering Southeast University Advanced Photonics Center Southeast University

Electrochemical, thermal, and photophysical properties of novel two- （BPODPA）, four- （BBPOPA）, and six-branch （TBPOA） triphenylamine chromophores are studied. The decomposition temperature of chro- mophores reaches 373 - 412 ℃. The electrochemical properties is explored by cyclic voltammetry. The ionization potential of chromophores is in the range of 5.14 - 5.18 eV. Excitation at 400 nm reveals emission peaks at 483 - 487 nm and the fluorescence quantum yields are 0.73 - 0.75 in CH2Cl2. Two-photon absorption （TPA） properties of chromophores are measured by nonlinear transmission method. The maximum TPA cross-section values are measured at 758 nm to be 20369 GM （1 GM=10^-50 cm^4 -s/photon） for TBPOA, 7024 GM for BBPOPA, and 1227 GM for BPODPA, respectively. When pumped with 800-nm laser irradiation, chromophores show strong two-photon excited blue-green fluorescence at 502 - 518 nm. These results provide a basis for understanding the electronic and optical properties of the conjugated multi-branch chromoohore in terms of the underlying molecular and electronic structures.

关键词： BPO nm Electrochemical,thermal,and photophysical properties of novel two-photon absorption chromophores

Investigations on serviceability control of long-span structures under human-induced excitation

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Earthquake Engineering and Engineering Vibration 2012年第1期11卷 57-71页

作者： Chen Xin Ding Youliang Li Ai-qun Zhang Zhiqiang Sun Peng Key Laboratory of Concrete and Prestressed Concrete Structure of Ministry of Education Southeast University Nanjing 210096 China School of Civil Engineering Suzhou University of Science and Technology Suzhou 215011 China

The increasing strength of new structural materials and the span of new structures, accompanied by aesthetic requirements for greater slenderness, are resulting in more applications of long-span structures. In this paper, serviceability control technology and its design theory are studied. First, a novel tuned mass damper （TMD） with controllable stiffness is developed. Second, methods for modeling human-induced loads are proposed, including standing up, walking, jumping and running, and an analysis method for long-span floor response is proposed based on a finite element model. Third, a design method for long-span floors installed with a multiple TMD （MTMD） system considering human comfort is introduced, largely based on a study of existing literature. Finally, a design, analysis and field test is conducted using several large scale buildings in China including the Beijing Olympic Park National Conference Center, Changsha New Railway Station and the Xi＇an Northern Railway Station. The analytical and field test results show that the MTMD system designed using the proposed method is capable of effectively mitigating the vertical vibration of long-span floor structures. The study presented in this paper provides an important reference for the analysis of vibration serviceability of similar long-span floors and design of control system for these structures.

关键词： long-span floor vibration control TMD human-inducing loads vibration serviceability

Design and experimental verification of a new multi-functional bridge seismic isolation bearing

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Journal of Zhejiang university-science A(Applied Physics & Engineering) 2012年第12期13卷 904-914页

作者： Chen-xi XING Hao WANG Ai-qun LI Ji-rong WU MOE Key Laboratory of Concrete and Prestressed Concrete Structures Southeast UniversityNanjing 210096China

A new multi-functional bridge seismic isolation bearing(MFBSIB) is designed and its mechanical model is developed in this *** an upper sliding device and a lower energy dispassion isolation device effectively,the new MFBSIB can adjust the deformation caused by temperature,vehicle breaks,and concrete creep,etc.,in addition to dissipating *** switch of 'slide-isolation' is achieved and the efficiency of both upper and lower parts is validated through experiment with a *** shear performance curve established in this paper is verified to be efficient in describing the mechanical characteristics of the bearing through *** is proved through both numerical calculation and experimental analysis that the new MFBSIB is endowed with enough vertical rigidity,good energy dissipation ability,stable overall performance,and good realization in expected *** performance is slightly influenced by shear stress,while affected by vertical pressure,loading frequency,slide limit,etc.,*** results could provide reference for study and application of the new MFBSIB.

关键词： Seismic isolation bearing Sliding device Finite element analysis Model experiment Bridge