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Analysis of the heat transfer in unsymmetrically heated triangular microchannels in slip flow regime

Science China(Technological Sciences) 2004年第4期47卷 436-446页

作者： ZHU Xun liao qiang XIN Mingdao Institute of Engineering Thermophysics Chongqing University Chongqing 400044 China Institute of Engineering Thermophysics Chongqing University Chongqing 400044 China Institute of Engineering Thermophysics Chongqing University Chongqing 400044 China

A theoretical analysis of heat transfer characteristics is presented for the fully developed laminar flow of the incompressible gas in the triangular microchannels heated unsymmetrically with constant axial heat flux. Through solving the energy equation with temperature jump boundary conditions in slip flow regime by virtue of a computation- oriented method of the orthonormal function analysis, the dimensionless temperature profiles and the average Nusselt number for various thermal boundary conditions are obtained. The effects of Knudsen number, aspect ratio, and thermal boundary conditions on the heat transfer are discussed. The calculated results show that the orthonormal function method can be used to study the heat transfer characteristics of the unsymmetrically heated triangular microchannels. The average Nusselt number in triangular microchannels is lower for slip flow than for no-slip flow, and decreases with increasing Knudsen number. The aspect ratios and thermal boundary conditions of triangular microchannels have significant influences on the change of average Nusselt numbers with the increase in the Knudsen number. For the equilateral triangular microchannels, the decrease of the Nusselt number ratio due to temperature jump is smaller at large Knudsen number and larger at small Knudsen number on the boundary condition of bottom wall heated alone as compared with the one on the boundary condition of two heated hypotenuse walls. The correlations of the average Nusselt number with the Knudsen number for equilateral triangular microchannels are obtained.

关键词： slip flow regime, triangular microchannel, unsymmetrical thermal boundary, heat transfer.

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Liquid droplet movement on horizontal surface with gradient surface energy

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Science China(Technological Sciences) 2006年第6期49卷 733-741页

作者： liao qiang WANG Hong ZHU Xun LI Mingwei Institute of Engineering Thermophysics Chongqing University Chongqing 400044 China Institute of Engineering Thermophysics Chongqing University Chongqing 400044 China Institute of Engineering Thermophysics Chongqing University Chongqing 400044 China Institute of Engineering Thermophysics Chongqing University Chongqing 400044 China

A surface with gradient surface energy was fabricated on a silicon wafer by using the chemical vapor deposition (CVD) technology with the dodecyltrichlorosilane (C12H25Cl3Si) vapor which was adsorbed chemically on the surface of the silicon wafer to form a self-assemble monolayer (ASM); thus a gradient profile of wettability. The microscopic contours of the gradient surface were measured with Seiko SPA400 atom force microscope (AFM). And the surface wettability profile was characterized by the sessile drop method, measuring the contact angle of fine water droplets that lay on the gradient surface, to represent the distribution of the surface energy on the surface. Using a high-speed video imaging system, the motion of water droplet on the horizontal gradient surface was visualized; the transient velocity was measured under ambient condition. The experimental results show that the liquid droplets can be driven to move from hydrophobic side to hydrophilic side on the horizontal gradient surface; the velocity of droplet can reach up to 40 mm/s. In addition, the motion of the water droplet can be generally divided into two stages: an acceleration stage; a deceleration stage. The droplet presents a squirming movement on the surface with a lower peak velocity; a larger extent of deceleration motion. And the static advancing contact angle of the droplet is obviously larger than the dynamic advancing contact angle on the gradient energy surface.

关键词： chemical vapor deposition, surface with gradient surface energy, contact angle profile, droplet motion.

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Mechanical properties of electroformed copper layers with gradient microstructure

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International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 69-74页

作者： qiang liao Li-qun Zhu Hui-cong Liu Wei-ping Li School of Materials Science and Engineering Beihang University Beij ing 100191 China

The electroformed copper layer with gradient microstructure was prepared using the ultrasonic technique. The microstructure of the electroformed copper layer was observed by using an optical microscope （OM） and a scanning electron microscope （SEM）. The preferred orientations of the layer were characterized by X-ray diffraction （XRD）. The mechanical properties were evaluated with a Vicker＇s hardness tester and a tensile tester. It is found the gradient microstructure consists of two main parts： the outer part （faraway substrate） with columnar crystals and the inner part （nearby substrate） with equiaxed grains. The Cu-（220） preferred orientation increases with the increasing thickness of the copper layer. The test results show that the microhardness of the electroformed copper layer decreases with increasing grain size along the growth direction and presents a gradient distribution. The tensile strength of the outer part of the electroformed copper layer is higher than that of the inner part but at the cost of ductility. Meanwhile, the integral mechanical properties of the electroformed copper with gradient microstrucmre are significantly improved in comparison with the pure copper deposit.

关键词： electroforming copper layer gradient rnicrostructure mechanical properties preferred orientation

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Pore-scale lattice Boltzmann simulation of flow and mass transfer in bioreactor with an immobilized granule for biohydrogen production

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Science Bulletin 2017年第1期62卷 22-30页

作者： qiang liao Yan-Xia Yang Xun Zhu Rong Chen Qian Fu Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing University Ministry of Education Chongqing 400030 China Institute of Engineering Thermophysics Chongqing University Chongqing 400030 China

The photo bioreaction combined with flow and mass transfer is simulated with pore-scale lattice Boltzmann （LB） method, which is the scenario of a bioreactor filled with a porous granule immobilized photosynthetic bacteria cells for hydrogen production. The quartet structure generation set （QSGS） is used to generate porous structure of the immobilized granule. The effects of porosity of the immobilized granule on flow and concentration fields as well as the hydrogen production performance are investi- gated. Higher porosity facilitates the substrate solution smoothly flowing through the porous granule with increasing velocity, and thus results in higher product concentration inside the immobilized gran- ule. Additionally, the substrate consumption efficiency increases, while hydrogen yield slightly decreases with increasing porosity, and they tend to stable for the porosity larger than 0.5. Furthermore, the LB numerical results have a good agreement with the experimental results. It is demonstrated that the pore-scale LB simulation method coupling with QSGS is available to simulate the photo hydrogen produc- tion in the hioreactor with porous immobilized granules.

关键词： Lattice Boltzmann method Pore scale Immobilized granule Photo biohydrogen production

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Anion Exchange Membrane Based on Interpenetrating Polymer Network with Ultrahigh Ion Conductivity and Excellent Stability for Alkaline Fuel Cell

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Research 2020年第1期2020卷 788-798页

作者： Lingping Zeng Qian He Yunchuan liao Shangyi Kuang Jianchuan Wang Wei Ding qiang liao Zidong Wei School of Chemistry&Chemical Engineering Chongqing University400044 ChongqingChina School of Energy and Power Engineering Chongqing University400044 ChongqingChina

A high-performance anion exchange membrane(AEM)is critical for the development of alkaline fuel *** this work,AEMs with an interpenetrating polymer network(IPN)are *** electron microscope clearly reveals a highly efficient“ion channel”network,which is constructed with a small amount of cation exchange *** specially designed ion channel leads to extraordinary hydroxide conductivity(e.g.,257.8 mS cm^(-1) at 80℃)of IPN AEMs at moderate ion exchange capacity(IEC=1:75 mmol g^(-1)),as well as excellent long-term alkaline stability at harsh condition which showed that 81%of original conductivity can be retained after a long time for 1248 ***,a remarkable peak power density of 1.20 Wcm^(-2)(0.1 MPa backpressure)with nonprecious metal(FeNx-CNTs)as oxygen reduction reaction(ORR)catalyst in a fuel cell test was *** work offers a general strategy to prepare high-performance AEMs based on IPN structure design.

关键词： alkaline exchange network

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A lobe-specific lymphadenectomy protocol for solitary pulmonary nodules in non-small cell lung cancer

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Chinese Journal of Cancer Research 2015年第6期27卷 538-544页

作者： Xue-Ning Yang Ze-Rui Zhao Wen-Zhao Zhong qiang Nie Ri-qiang liao Song Dong Division of Surgery Department of Pulmonary Oncology Guangdong Lung Cancer Institute Guangdong General Hospital and Guangdong Academy of Medical Sciences

Background： We want to establish a lobe-specific mediastinal lymphadenectomy protocol for solitary pulmonary nodules （SPNs） in non-small cell lung cancer （NSCLC）. Methods： We retrospectively analyzed 401 patients with pathological diagnoses of NSCLC who underwent lobectomy, bilobectomy, or pneumonectomy with systematic lymphadenectomy from March 2004 to June 2011 in our hospital. All of the patients enrolled had a SPN preoperatively. Information about the primary tumor location, lymph node metastasis, and other baseline data were collected. Stepwise logistic regression was used to identify the key factors indicating non-regional mediastinal lymph node metastases （NRM）. Results： Of the primary tumors, 117, 39, 74, 104, and 67 were in the right upper lung （RUL）, right middle lung （RML）, right lower lung （RLL）, left upper lung （LUL）, and left lower lung （LLL）, respectively. Stepwise regression showed that #2,4, #10,11, and #10,11 as well as #7 was the key lymph node station for RUL, LUL, and lower lobes： #2,4 [odds ratio （OR）=28.000, 95% confidence interval （CI）： 2.917-268.790, P=0.004] for RUL, #10,11 （OR=31.667, 95% CI： 2.502-400.833, P=0.008） for LUL, #10,11 （OR=19.540, 95% CI： 4.217-90.541, P〈0.001） and #7 （OR=7.395, 95% CI： 1.586-34.484, P=0.011） for lower lobes, respectively. Patients with tumors 〉2 cm rarely had NRM without primary regional mediastinal involvement. Conclusions： With rigid consideration, a lobe-specific lymphadenectomy is feasible in practice. This protocol can be used when the lobe-specific key nodes are negative in intraoperative frozen sections, especially for NSCLC diagnosed as SPN 〈2 cm preoperatively.

关键词： Lung cancer surgery lymph nodes selective dissection lobe-specific

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CNN-LSTM based incremental attention mechanism enabled phase-space reconstruction for chaotic time series prediction

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Journal of Electronic Science and Technology 2024年第2期22卷 77-90页

作者： Xiao-Qian Lu Jun Tian qiang liao Zheng-Wu Xu Lu Gan Bidding and Purchasing Center University of Electronic Science and Technology of ChinaChengdu611731China Yibin Research Institute University of Electronic Science and Technology of ChinaYibin644000China School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu611731China

To improve the prediction accuracy of chaotic time series and reconstruct a more reasonable phase space structure of the prediction network,we propose a convolutional neural network-long short-term memory(CNN-LSTM)prediction model based on the incremental attention ***,a traversal search is conducted through the traversal layer for finite parameters in the phase ***,an incremental attention layer is utilized for parameter judgment based on the dimension weight criteria(DWC).The phase space parameters that best meet DWC are selected and fed into the input ***,the constructed CNN-LSTM network extracts spatio-temporal features and provides the final prediction *** model is verified using Logistic,Lorenz,and sunspot chaotic time series,and the performance is compared from the two dimensions of prediction accuracy and network phase space ***,the CNN-LSTM network based on incremental attention is compared with long short-term memory(LSTM),convolutional neural network(CNN),recurrent neural network(RNN),and support vector regression(SVR)for prediction *** experiment results indicate that the proposed composite network model possesses enhanced capability in extracting temporal features and achieves higher prediction ***,the algorithm to estimate the phase space parameter is compared with the traditional CAO,false nearest neighbor,and C-C,three typical methods for determining the chaotic phase space *** experiments reveal that the phase space parameter estimation algorithm based on the incremental attention mechanism is superior in prediction accuracy compared with the traditional phase space reconstruction method in five networks,including CNN-LSTM,LSTM,CNN,RNN,and SVR.

关键词： Chaotic time series Incremental attention mechanism Phase-space reconstruction

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Performance of a thermally regenerative ammonia-based battery using gradient-porous copper foam electrodes

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Science China(Technological Sciences) 2021年第4期64卷 696-704页

作者： LU Zhiqiang ZHANG YongSheng ZHANG Liang LI Jun FU Qian ZHU Xun liao qiang Key Laboratory of Low-Grade Energy Utilization Technologies and Systems Ministry of EducationChongqing 400030China Institute of Engineering Thermophysics School of Energy and Power EngineeringChongqing UniversityChongqing 400030China

Gradient-porous copper foam electrodes were applied to alleviate the adverse effects of the uneven current distribution of electrodes along the electrolyte flow direction in thermally regenerative ammonia-based batteries(TRABs).The results indicated that gradient-porous copper foam with a decreasing pore size(TRAB-LMS)provided the most uniform current distribution and generated the highest power density(15.5 W/m^(2)),total charge(1800 C)and energy density(1224 W h/m^(3)).With the increase in flow rate,the power density of the TRAB-LMS increased considerably within a certain range and then decreased slightly,with the optimal flowrate at 15 mL/*** the optimal flow rate,the performance of TRAB-LMS increased when the ammonia concentration rose from 0.5 to 2 M(1 M=1 mol L^(-1));however,it decreased slightly when the ammonia concentration further increased to 3 *** slight decrease in the cathode potential suggested that the flow and ammonia concentration beyond the optional values facilitated not only the transfer of ammonia into the porous anode,but also the crossover of ammonia from the anode to the cathode.

关键词： thermally regenerative ammonia-based battery gradient-porous electrode current distribution mass transfer

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Effect of operating parameters on the performance of thermally regenerative ammonia-based battery for low-temperature waste heat recovery

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Chinese Journal of Chemical Engineering 2021年第4期34卷 335-340页

作者： Yu Shi Liang Zhang Jun Li Qian Fu Xun Zhu qiang liao Yongsheng Zhang Key Laboratory of Low-grade Energy Utilization Technologies and Systems Ministry of EducationChongqing 400030China

This study investigated the important factors that affect the operating parameters of thermally regenerative ammoniabased batteries(TRABs),including the metal electrode type,membrane type,electrode surface area,electrode distance,electrolyte concentration,and ammonia *** experimental results showed that the maximum power density of TRABs with a Cu electrode was 40.0 W·m^(2),which was considerably higher than that with Ni(0.34 W·m^(2))and Co(0.14 W·m^(2))*** with an anion exchange membrane had a 28.6%higher maximum power density than those with a cation exchange *** increased electrode surface resulted in an increased maximum power but a decreased maximum power *** a certain range,TRAB performance was enhanced with decreased electrode distance and increased electrolyte *** increased ammonia concentration resulted in enhanced ammonia transfer and improved the TRAB performance.

关键词： Electrochemistry Thermally regenerative ammonia-based battery Recovery Renewable energy

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Vulnerability of Water Resources and Its Spatial Heterogeneity in Haihe River Basin, China

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Chinese Geographical Science 2014年第5期24卷 525-539页

作者： XIA Jun CHEN Junxu WENG Jianwu YU Lei QI Junyu liao qiang Key Laboratory of Water Cycle & Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University University of Chinese Academy of Sciences Zhejiang Economic Information Center Haihe River Water Conservancy Committee Faculty of Forestry and Environmental Management University of New Brunswick

To manage water resources effectively, a multiscale assessment of the vulnerability of water resources on the basis of political boundaries and watersheds is necessary. This study addressed issues on the vulnerability of water resources and provided a multiscale comparison of spatial heterogeneity under a climate change background. Using improved quantitative evaluation methods of vulnerabil- ity, the Theil index and the Shannon-Weaver index, we evaluated the vulnerability of water resources and its spatial heterogeneity in the Haihe River Basin in four scales, namely, second-class water resource regions （Class II WRRs）, third-class water resource regions （Class III WRRs）, Province-Class II WRRs, and Province-Class III WRRs. Results show that vulnerability enhances from the north to south in the different scales, and shows obvious spatial heterogeneity instead of moving toward convergence in multiscale assessment results. Among the Class II WRRs, the Tuhai-Majia River is the most vulnerable area, and the vulnerability of the Luanhe River is lower than that of the north of the Haihe River Basin, which in turn is lower than that of the south of the Haihe River Basin. In the scales of Class III WRRs and Province-Class III WRRs, the vulnerability shows obvious spatial heterogeneity and diversity measured by the Theil index and the Shannon-Weaver index. Multiscale vulnerability assessment results based on political boundaries and the watersheds of the Haihe River Basin innovatively provided in this paper are important and useful to characterize the real spatial pattern of the vulnerability of water resources and improve water resource management.

关键词： water resource vulnerability assessment Theil index Shannon-Weaver index spatial heterogeneity Haihe River Basin

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