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Synergetic effect of secondary nucleation and growth on the lithium carbonate particle size in the gas-liquid reactive crystallization of LiCl-NH3·H2O-CO2

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Particuology 2020年第4期18卷 10-17页

作者： Menghua Tian jianwei guo Zhi Wang jianwei Cao Xuzhong Gong Key Laboratory of Green Process and Engineering National Engineering Laboratory for Hydrometallurgical Cleaner Production TechnologyInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

In this study,the gas-liquid reactive crystallization of LiCl-NH3·H2O-CO2 was adopted to produce *** weakly alkaline nature of NH3·H2O in the absence of any recarbonation process resulted in a unimodal and easily controllable particle size distribution(PSD)of the obtained *** reaction temperature significantly influenced both the Li2CO3 particle size and *** increasing the temperature from 25 to 60℃,the volume weighted mean particle size increased from 50.5 to 100.5μm,*** Li2CO3 secondary nucleation rate and growth rate were obtained by focused beam reflectance measurements and a laser particle size analyzer,*** secondary nucleation rate of Li2CO3 reduced as a function of temperature,whereas the growth rate *** addition to improving the surface energy of the crystals to enhance the growth process,higher temperatures also reduced the supersolubility of Li2CO3,which also plays a role to decrease the secondary nucleation *** a constant temperature,supersaturation affects the Li2CO3 particle size through the synergistic effect of secondary nucleation and ***,with improved supersaturation,the mean particle size of Li2CO3 *** results provide a meaningful way to evaluate the crystallization process and to regulate the particle size.

关键词： Li2CO3 Gas-liquid reactive crystallization Particle size distribution Supersaturation Secondary nucleation Growth rate

On 2D approximations for dissolution problems in Hele-Shaw cells

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Science China(Physics,Mechanics & Astronomy) 2023年第3期66卷 104-120页

作者： jianwei guo Farid Laouafa Michel Quintard School of Mechanics and Aerospace Engineering Southwest Jiaotong UniversityChengdu 610031China National Institute for Industrial Environment and Risks(INERIS) Verneuil en Halatte 60550France Institut de Mecanique des Fluides de Toulouse(IMFT) Universite de ToulouseCNRSToulouse 31400France

In this paper, we study the dissolution problems occurring in laterally large 3D systems with very small dimensions along the third coordinate, such as fractures or Hele-Shaw cells. On the basis of the scale separation assumption, we apply upscaling to the 3D pore-scale model using the volume averaging method to develop 2D averaged equations. The influence of the choice of momentum equations on the accuracy of the 2D Hele-Shaw model is discussed, and we show that the results obtained using Darcy-Brinkman equations are better than those obtained using Darcy’s law, because of the consideration of the viscous boundary layer. The validity and accuracy of the resulting 2D model are assessed based on comparisons with full 3D solutions for problems corresponding to the existence of geometrical 3D features to which a simple averaging procedure along a line(i.e., the height of the gap) perpendicular to the 2D plane cannot be applied, such as the dissolution of pillars. The results show that when Péclet and Reynolds numbers exceed certain limits, 3D effects must be considered. Moreover, natural convection effects are important when the Rayleigh number is large.

关键词： dissolution Hele-Shaw cell upscaling natural convection

Novel methanol-tolerant Ir-S/C chalcogenide electrocatalysts for oxygen reduction in DMFC fuel cell

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Particuology 2011年第2期9卷 155-160页

作者： Jingyu Ma Desheng Ai Xiaofeng Xie jianwei guo Institute of Nuclear & New Energy Technology Tsinghua University Beijing 100084 China

Novel methanol-tolerant oxygen-reduction catalysts, iridium-sulphur （Ir-S） chalcogenides with different Ir/S atomic ratios, were synthesized via a precipitation method using H2IrCI6 and Na2SO3 as the Ir and S precursors. Powder X-ray diffraction （XRD） and transmission electron microscopy （TEM） were used to characterize the lrxSl_x/C chalcogenide catalysts. Particle size ranging from 2.5 to 2.8 nm though obvi- ous agglomeration was found on carbon support. However, these chalcogenide catalysts showed strong catalytic activity towards the oxygen reduction reaction （ORR） and high methanol tolerance, strongly suggesting these novel catalysts as promising candidates for direct methanol fuel cell （DMFC） cathode applications.

关键词： DMFCIridiumSulphurCathodic catalystOxygen reductionMethanol tolerant

Learning local shape descriptors for computing non-rigid dense correspondence

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Computational Visual Media 2020年第1期6卷 95-112页

作者： jianwei guo Hanyu Wang Zhanglin Cheng Xiaopeng Zhang Dong-Ming Yan National Laboratory of Pattern Recognition Institute of AutomationChinese Academy of SciencesBeijing 100190China University of Maryland-College Park MarylandUSA Shenzhen VisuCA Key Lab Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhenChina

A discriminative local shape descriptor plays an important role in various *** this paper,we present a novel deep learning framework that derives discriminative local descriptors for deformable 3D *** use local"geometry images"to encode the multi-scale local features of a point,via an intrinsic parameterization method based on geodesic polar *** new parameterization provides robust geometry images even for badly-shaped triangular *** a triplet network with shared architecture and parameters is used to perform deep metric learning;its aim is to distinguish between similar and dissimilar pairs of ***,a newly designed triplet loss function is minimized for improved,accurate training of the triplet *** solve the dense correspondence problem,an efficient sampling approach is utilized to achieve a good compromise between training performance and descriptor *** testing,given a geometry image of a point of interest,our network outputs a discriminative local descriptor for *** testing of non-rigid dense shape matching on a variety of benchmarks demonstrates the superiority of the proposed descriptors over the state-of-the-art alternatives.

关键词： local feature descriptor triplet CNN dense correspondence geometry image non-rigid shape

INHIBITION MECHANISM OF Na_2MoO_4 FOR CARBON STEEL IN 55% LiBr SOLUTION

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Chinese Journal of Mechanical Engineering 2007年第4期20卷 15-18页

作者： LIANG Chenghao HUANG Naibao guo jianwei HU Xianqi Electromechanics and Materials Engineering College Dalian Mantime University Dalian 116026 China School of Chemical Engineering Dalian University of Technology Dalian 116012 China Electromechanics and Materials Engineering College Dalian Maritime University Dalian 116026 Ch na nstitute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China

Electrochemical measurement and chemical immersion test are employed to investigate the inhibition mechanism of Na2MoO4 for carbon steel,which is studied in 55%LiBr＋0.07mol/L LiOH solution at high *** results indicate that the passive film on carbon steel surface is mainly composed of Fe3O4,and Mo is involved in the process of film forming,in a form of MoO3 and *** parametric analysis of the evolving potential and the blend potential of MoO2 shows that Mo mainly exists as MoO2 in passive film when the concentration of Na2MoO4 is lower than 150 mg/*** its concentration is greater than 150mg/L,it mainly exists as MoO3 inside the film and exists as MoO2 outside the ***4^2- is deoxidized as MoO2 on the surface of carbon steel,which may impede the corrosion of active-site and raise the blend potential of carbon steel,and then MoO4^2- adsorbs onto the defects of the passive film and decompounds as MoO3 during the process of film *** electric field caused by different valence of Mo in passive film may retard the dissolution of carbon steel and lead to an increase in the polarization impedance and a decrease in hydrogen *** a result,heavy concentrated Na2MoO4 solution（greater than 150mg/L）has excellent inhibition effect on carbon steel in LiBr solution.

关键词： LiBr solution Carbon steel Anticorrosion Na2MoO4

Fast determination of meso-level mechanical parameters of PFC models

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International Journal of Mining Science and Technology 2013年第1期23卷 157-162页

作者： guo jianwei Xu guoan Jing Hongwen Kuang Tiejun School of Safety Engineering China University of Mining & Technology Energy and Chemical Research Institute of Zhong Ping Shen Ma Group State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining & Technology School of Mechanics and Civil Engineering China University of Mining & Technology Sitai Coal Mine Datong Coal Mine Group

To solve the problems of blindness and inefficiency existing in the determination of meso-level mechanical parameters of particle flow code (PFC) models, we firstly designed and numerically carried out orthogonal tests on rock samples to investigate the correlations between macro-and meso-level mechanical parameters of rock-like bonded granular materials. Then based on the artificial intelligent technology, the intelligent prediction systems for nine meso-level mechanical parameters of PFC models were obtained by creating, training and testing the prediction models with the set of data got from the orthogonal tests. Lastly the prediction systems were used to predict the meso-level mechanical parameters of one kind of sandy mudstone, and according to the predicted results the macroscopic properties of the rock were obtained by numerical tests. The maximum relative error between the numerical test results and real rock properties is 3.28% which satisfies the precision requirement in engineering. It shows that this paper provides a fast and accurate method for the determination of meso-level mechanical parameters of PFC models.

关键词： Particle flow code Meso-level mechanical parameter Macroscopic property Orthogonal test Intelligent prediction

Joint specular highlight detection and removal in single images via Unet-Transformer

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Computational Visual Media 2023年第1期9卷 141-154页

作者： Zhongqi Wu jianwei guo Chuanqing Zhuang Jun Xiao Dong-Ming Yan Xiaopeng Zhang National Laboratory of Pattern Recognition Institute of AutomationChinese Academy of SciencesBeijing 100190China The School of Artificial Intelligence University of Chinese Academy of SciencesBeijingChina

Specular highlight detection and removal is a fundamental problem in computer vision and image *** this paper,we present an efficient endto-end deep learning model for automatically detecting and removing specular highlights in a single *** particular,an encoder–decoder network is utilized to detect specular highlights,and then a novel Unet-Transformer network performs highlight removal;we append transformer modules instead of feature maps in the Unet *** also introduce a highlight detection module as a mask to guide the removal ***,these two networks can be jointly trained in an effective *** to the hierarchical and global properties of the transformer mechanism,our framework is able to establish relationships between continuous self-attention layers,making it possible to directly model the mapping between the diffuse area and the specular highlight area,and reduce indeterminacy within areas containing strong specular highlight *** on public benchmark and real-world images demonstrate that our approach outperforms state-of-the-art methods for both highlight detection and removal tasks.

关键词： specular highlight detection specular highlight removal Unet-Transformer

Perspectives on point cloud-based 3D scene modeling and XR presentation within the cloud-edge-client architecture

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Visual Informatics 2023年第3期7卷 59-64页

作者： Hongjia Wu Hongxin Zhang Jiang Cheng jianwei guo Wei Chen State Key Lab of CAD&CG Zhejiang UniversityHangzhouZhejiangChina China Mobile Communications Group Jiangxi Co. Ltd.China State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of AutomationChinese Academy of SciencesChina

With the support of edge computing,the synergy and collaboration among central cloud,edge cloud,and terminal devices form an integrated computing ecosystem known as the cloud-edge-client *** integration unlocks the value of data and computational power,presenting significant opportunities for large-scale 3D scene modeling and XR *** this paper,we explore the perspectives and highlight new challenges in 3D scene modeling and XR presentation based on point cloud within the cloud-edge-client integrated *** also propose a novel cloud-edge-client integrated technology framework and a demonstration of municipal governance application to address these challenges.

关键词： The cloud-edge-client integrated architecture 3D scene perception and modeling XR rendering Cloud-edge-client integrated visualization

Analyzing surface sampling patterns using the localized pair correlation function

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Computational Visual Media 2016年第3期2卷 219-230页

作者： Weize Quan jianwei guo Dong-Ming Yan Weiliang Meng Xiaopeng Zhang NLPR-LIAMA Institute of Automation Chinese Academy of Sciences

Point distributions with different characteristics have a crucial influence on graphics applications. Various analysis tools have been developed in recent years, mainly for blue noise sampling in Euclidean domains. In this paper, we present a new method to analyze the properties of general sampling patterns that are distributed on mesh surfaces. The core idea is to generalize to surfaces the pair correlation function(PCF) which has successfully been employed in sampling pattern analysis and synthesis in 2D and 3D. Experimental results demonstrate that the proposed approach can reveal correlations of point sets generated by a wide range of sampling algorithms. An acceleration technique is also suggested to improve the performance of the PCF.

关键词： point distribution spectral analysis pair correlation function(PCF) mesh surface