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Lattice Boltzmann simulation of phase change and heat transfer characteristics in the multi-layer deposition

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Applied Mathematics and Mechanics(English Edition) 2021年第4期42卷 553-566页

作者： Yanlin ren Zhaomiao LIU Yan PANG xiang WANG Yuandi XU College of Mechanical Engineering and Applied Electronics Technology Beijing University of TechnologyBeijing 100124China Beijing Key Laboratory of Advanced Manufacturing Technology Beijing University of TechnologyBeijing 100124China

The metal droplets deposition method(MDDM)is a rapid prototyping technology,implemented via metallurgy bonding within *** anisotropy of heat transfer and re-melting is caused by an asymmetric deposition process.A lattice Boltzmann method(LBM)model is established to predict the heat transfer and phase change in the multi-layer *** prediction model is verified by the experimental temperature profiles in existing *** monitoring points are set to compare the temperature profiles,and decoupling analyze the heat transfer mechanism in different *** negative relationships between the re-molten volume of the temperature difference,as well as the influence of the dispositive position and the relative position of the adjacent component are observed and analyzed under the heat *** work is helpful to choose the appropriate temperature conditions and the optimal dispositive method.

关键词： multi-layer deposition phase change heat transfer lattice Boltzmann method(LBM)

Energy-limiting factor for coal and gas outburst occurrence in intact coal seam

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International Journal of Mining Science and Technology 2021年第4期31卷 729-742页

作者： Qingyi Tu Yuanping Cheng Sheng Xue Ting ren xiang Cheng State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China Faculty of Safety Engineering China University of Mining and TechnologyXuzhou 221116China School of Civil Mining&Environmental EngineeringUniversity of WollongongNSW 2522Australia

This research reviewed the mechanics and gas desorption properties of intact coal,and tested the crushing work ratios of different intact coals,and then,studied the stress conditions for the failure or crushing of intact coal and the gas demand for the pulverization of intact coal *** a real-life outburst case is examined,the required minimum stress for intact coal outburst is *** study concludes that the crushing work ratios of three intact coal samples vary from 294.3732 to 945.8048 J/m^(2).For the real-life case,more than 2300 MJ of transport work is needed,and 10062.09,7046.57 and 5895.47 m^(3) of gas is required when the gas pressure is 1,2 and 3 MPa,*** crushing work exceeds the transport work and even reaches 13.96 times of the transport *** to provide such an enormous crushing work is an energy-limiting factor for the outburst in intact *** strain energy is needed for the crushing work,and the required minimum stress is over 54.35 MPa,even reaching 300.44 *** minimum stresses far exceed the in-situ vertical and horizontal stresses that can be provided at the 300–700 m mining depth range.

关键词： Coal and gas outburst Intact coal Crushing work ratio Geological factors Outburst energy

Localization of s-Wave and Quantum Effective Potential of a Quasi-free Particle with Position-Dependent Mass

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Communications in Theoretical Physics 2006年第5X期46卷 819-825页

作者： JU Guo-Xing xiang Yang ren Zhong-Zhou Department of Physics Nanjing University Nanjing 210093 China

The properties of the 8-wave for a quasl-free partide with position-dependent mass （PDM） have been discussed in details. Differed from the system with constant mass in which the localization of the s-wave for the free quantum particle around the origin only occurs in two dimensions, the quasi-free particle with PDM can experience attractive forces in D dimensions except D = 1 when its mass function satisfies some conditions. The effective mass of a particle varying with its position can induce effective interaction, which may be attractive in some cases. The analytical expressions of the eigenfunctions and the corresponding probability densities for the 8-waves of the two- and three-dimensional systems with a special PDM are given, and the existences of localization around the origin for these systems are shown.

关键词： position-dependent mass s-wave Schrodinger equation dimensionality of the space localization eigenfunction probability density

Ground Nephogram Recognition Algorithm Based on Selective Neural Network Ensemble

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Computers, Materials & Continua 2020年第5期63卷 621-631页

作者： Tao Li xiang Li Yongjun ren Jinyue Xia College of Electronic and Information Engineering Nanjing University of Information Science and TechnologyNanjing210044China College of Computer and Software Nanjing University of Information Science and TechnologyNanjing210044China International Business Machines Corporation(IBM) New YorkUSA

In view of the low accuracy of traditional ground nephogram recognition model,the authors put forward a k-means algorithm-acquired neural network ensemble method,which takes BP neural network ensemble model as the basis,uses k-means algorithm to choose the individual neural networks with partial diversities for integration,and builds the cloud form classification *** simulation experiments on ground nephogram samples,the results show that the algorithm proposed in the article can effectively improve the Classification accuracy of ground nephogram recognition in comparison with applying single BP neural network and traditional BP AdaBoost ensemble algorithm on classification of ground nephogram.

关键词： Cloud shape k-means BP neural network adaboost

Pressure and Temperature Feasibility of NCEP/NCAR Reanalysis Data at ***

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Journal of Mountain Science 2008年第1期5卷 32-37页

作者： XIE Aihong ren Jiawen QIN xiang KANG Shikang State Key Laboratory of Cryospheric Sciences Cold and Arid Regions Environment and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China

*** (27°54' N,86°54' E),the highest peak,is often referred to as the earth's 'third' pole,at an elevation of 8844.43 m. Due to the difficult logistics in the extreme high elevation regions over the Himalayas,observational meteorological data are very few on Mt. Everest. In 2005,an automatic weather station was operated at the East Rongbuk glacier Col of Mt. Everest over the Himalayas. The observational data have been compared with the reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR),and the reliability of NCEP/NCAR reanalysis data has been investigated in the Himalayan region,after the reanalyzed data were interpolated in the horizontal to the location of Mt. Everest and in the vertical to the height of the observed sites. The reanalysis data can capture much of the synoptic-scale variability in temperature and pressure,although the reanalysis values are systematically lower than the observation. Furthermore,most of the variability magnitude is,to some degree,underestimated. In addition,the variation extracted from the NCEP/NCAR reanalyzed pressure and temperature prominently appears one-day lead to that from the observational data,which is more important from the standpoint of improving the safety of climbers who attempt to climb Mt. Everest peak.

关键词： NCEP/NCAR daily averaged pressure daily minimum temperature high Himalayas Mt.Everest

Studies on Preparation of Co-Bi Alloy Films by Electrodeposition From Nonaqueous Medium

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Chemical Research in Chinese Universities 2003年第4期19卷 499-503页

作者： LI Gao-ren TONG Ye-xiang LIU Guan-kun School of Chemistry and Chemical Engineering Zhongshan UniversityGuangzhou 510275P.R.China

Cyclic voltammetry and potentiostatic electrolysis were used to investigate the preparation of Co-Bi alloy films in a LiClO 4-DMSO system. The experimental results indicate that the Co-Bi alloy films containing 14 35%-29 77% Co can be prepared via potentionstatic electrolysis on Cu substrates, at deposition potential -1 10--1 65 V( vs. SCE) and by controlling the system composition and deposition condition. They are uniform gray films with a metallic luster and they are adhered firmly to the Cu substrate. The films were analyzed by EDS, SEM and XRD. After heat treatment of crystallization at 275 ℃ for 1 h, the alloy phase of Co-Bi can be confirmed via the XRD pattern.

关键词： Bismuth Co-Bi alloy film Electrodeposition DMSO

Flow regimes of the immiscible liquids within a rectangular microchannel

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Acta Mechanica Sinica 2021年第10期37卷 1544-1556,I0003页

作者： xiang Wang Yan Pang Yilin Ma Yanlin ren Zhaomiao Liu College of Mechanical Engineering and Applied Electronics Technology Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing100124China Beijing Key Laboratory of Advanced Manufacturing Technology Beijing University of TechnologyBeijing100124China

Flow regimes of two immiscible liquids at the cross junction within a rectangular microchannel are experimentally *** of the flow regimes including critical conditions and interfacial deformations are *** is found that the occurrence of the tubing regime is favored by increased viscosity of the dispersed phase or reduced cross-sectional aspect ratio,leading to the shrinkage of the flow rate range that could produce *** order to reveal the physical mechanism,the force analysis is carried out based on the tunnel structure formed between the interface and channel side walls within the rectangular *** reshaping stage and pinch-off stage are mainly driven by the interfacial tension,leading to far larger neck thinning rate compared to the superficial velocity of either *** filling stage and squeezing stage are dominated by the pressure drop across the dispersed tip while the role of the shear force becomes more important with increasing tunnel *** filling period is estimated as t2≈kHwn02/Qd with k=1.34 and the squeezing period is expressed as t3/Tc=0.3Cac−*** to the force analysis,the critical tip velocity under dripping scales with three key parameters,which can be expressed as(utip/U)*~QcLtip/wtunnel3.

关键词： Cross junction Flow regime Liquid interface Force analysis Rectangular microchannel

Impact of the thermal effect on the load-carrying capacity of a slipper pair for an aviation axial-piston pump

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Chinese Journal of Aeronautics 2018年第2期31卷 395-409页

作者： Hesheng tanG Yaobao YIN Yan ren Jiawei xiang Jun CHEN School of Mechanical Engineering WenZhou University School of Mechanical Engineering Tongji University Sany Heavy Industry Co. Ltd

A thermal hydraulic model based on the lumped parameter method is presented to analyze the load-carrying capacity of a slipper pair in an aviation axial-piston pump under specified operating conditions. Both theoretical and experimental results are presented to demonstrate the validity of the thermal hydraulic model. The results illustrate that the squeezing force and thermal wedge bearing force are the main factors that affect the film thickness and load-carrying *** high oil temperature and high load pressure, the film thickness decreases with increasing clamping force due to a combined action of the squeezing bearing force and the thermal wedge bearing force, but the load-carrying capacity will increase. An increase of the film thickness is proven to be beneficial under high shaft rotational speed but especially dangerous as it strongly increases the ripple amplitude of the film thickness, which leads to decreasing the load-carrying capacity. The structural parameters of the slipper can be optimized to achieve desired performance, such as the slipper radius ratio and orifice length diameter ratio. To satisfy the requirement of the load-carrying capacity, the slipper radius ratio should be selected from 1.4 to 1.8, and the orifice length diameter ratio should be selected from 4 to 5.

关键词： Aviation axial piston pumpFluid lubrication Load-carrying capacity Slipper pair Thermal effect

High-throughput and simultaneous inertial separation of tumor cells and clusters from malignant effusions using spiral-contraction-expansion channels

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Microsystems & Nanoengineering 2024年第2期10卷 91-99页

作者： Zhixian Zhu Hui ren Dan Wu Zhonghua Ni Nan xiang School of Mechanical Engineering and Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical InstrumentsSoutheast University211189NanjingChina School of Mechanical Technology Wuxi Institute of TechnologyNo.1600 Gaolang West Road214129WuxiChina Department of Oncology Jiangyin People’s Hospital214400JiangyinChina

Tumor cell clusters are regarded as critical factors in cancer pathophysiology,and increasing evidence of their higher treatment resistance and metastasis compared to single tumor cells has been ***,existing cell separation methods that are designed for single tumor cells cannot be used to simultaneously purify tumor cell *** address this problem,we demonstrated a microfluidic approach for the high-throughput,continuous-flow ternary separation of single tumor cells,tumor cell clusters,and WBCs from clinical pleural or abdominal effusions by coupling slanted spiral channels and periodic contraction-expansion *** first systematically explored the influence of particle size and flow rate on particle *** separation performance indicated that 94.0%of WBCs were removed and more than 97%of MDA-MB-231 tumor cells were recovered at a high flow rate of 3500µL/***,more than 90%of tumor cell clusters were effectively preserved after ***,we successfully applied our device for the ternary separation of single tumor cells,tumor cell clusters,and WBCs from different malignant effusions collected from patients with metastatic ***,our spiral-contraction-expansion device has potential as a sample pretreatment tool for the cytological diagnosis of malignant effusions.

关键词： separation contraction removed