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Modeling and petrophysical properties of digital rock models with various pore structure types: An improved workflow

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International Journal of Coal Science & Technology 2023年第5期10卷 38-56页

作者： Xiaobin Li Wei Wei Yuxuan Xia Lei Wang Jianchao Cai Key Laboratory of Tectonics and Petroleum Resources Ministryof EducationChina University of GeosciencesWuhan 430074China School of Geophysics and Geomatics China University of GeosciencesWuhan 430074China State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China

Pore structure is a crucial factor affecting the physical properties of porous materials,and understanding the mechanisms and laws of these effects is of great significance in the fields of geosciences and petroleum engineering.However,it remains a challenge to accurately understand and quantify the relationship between pore structures and effective properties.This paper improves a workflow to focus on investigating the effect of pore structure on physical properties.First,a hybrid modeling approach combining process-based and morphology-based methods is proposed to reconstruct 3D models with diverse pore structure types.Then,the characteristics and differences in pore structure in these models are compared.Finally,the varia-tion laws and pore-scale mechanisms of the influence of pore structure on physical properties(permeability and elasticity)are discussed based on the reconstructed models.The relationship models between pore structure parameters and perme-ability/elastic parameters in the grain packing model are established.The effect of pore structure evolution on permeability/elasticity and the microscopic mechanism in three types of morphology-based reconstruction models are explored.The influence degree of pore structure on elastic parameters(bulk modulus,shear modulus,P-wave velocity,and S-wave veloc-ity)is quantified,reaching 29.54%,51.40%,18.94%,and 23.18%,respectively.This work forms a workflow for exploring the relationship between pore structures and petrophysical properties at the microscopic scale,providing more ideas and references for understanding the complex physical properties in porous media.

关键词： Hybrid modeling Pore structure Petrophysical properties Microscopic mechanism

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Graphene-based nanomaterials for cancer therapy and anti-infections

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Bioactive Materials 2022年第8期7卷 335-349页

作者： Yan Wang Juan li Xiaobin Li Jinping Shi Zhaotan Jiang Can Yang Zhang School of Physics Beijing Institute of TechnologyBeijing100081China Advanced Research Institute for Multidisciplinary Science Beijing Institute of TechnologyBeijing100081China Institute of Biopharmaceutical and Health Engineering Shenzhen International Graduate SchoolTsinghua UniversityShenzhen518055China

Graphene-based nanomaterials(GBNMs)has been thoroughly investigated and extensively used in many biomedical fields,especially cancer therapy and bacteria-induced infectious diseases treatment,which have attracted more and more attentions due to the improved therapeutic efficacy and reduced reverse effect.GBNMs,as classic two-dimensional(2D)nanomaterials,have unique structure and excellent physicochemical properties,exhibiting tremendous potential in cancer therapy and bacteria-induced infectious diseases treatment.In this review,we first introduced the recent advances in development of GBNMs and GBNMs-based treatment strategies for cancer,including photothermal therapy(PTT),photodynamic therapy(PDT)and multiple combination therapies.Then,we surveyed the research progress of applications of GBNMs in anti-infection such as antimicrobial resistance,wound healing and removal of biofilm.The mechanism of GBNMs was also expounded.Finally,we concluded and discussed the advantages,challenges/limitations and perspective about the development of GBNMs and GBNMs-based therapies.Collectively,we think that GBNMs could be potential in clinic to promote the improvement of cancer therapy and infections treatment.

关键词： Graphene Phototherapy Cancer therapy Anti-infection 2D materials

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Unsupervised hyperspectral unmixing based on robust nonnegative dictionary learning

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Journal of Systems Engineering and Electronics 2022年第2期33卷 294-304页

作者： li Yang JIANG Bitao li xiaobin TIAN Jing SONG Xiaorui Department of Space Information Space Engineering UniversityBeijing 101400China Beijing Institute of Remote Sensing Information Beijing 100192China

Considering the sparsity of hyperspectral images(HSIs),dictionary learning frameworks have been widely used in the field of unsupervised spectral unmixing.However,it is worth mentioning here that existing dictionary learning method-based unmixing methods are found to be short of robustness in noisy contexts.To improve the performance,this study specifically puts forward a new unsupervised spectral unmixing solution.For the reason that the solution only functions in a condition that both endmembers and the abundances meet non-negative con-straints,a model is built to solve the unsupervised spectral un-mixing problem on the account of the dictionary learning me-thod.To raise the screening accuracy of final members,a new form of the target function is introduced into dictionary learning practice,which is conducive to the growing robustness of noisy HSI statistics.Then,by introducing the total variation(TV)terms into the proposed spectral unmixing based on robust nonnega-tive dictionary learning(RNDLSU),the context information under HSI space is to be cited as prior knowledge to compute the abundances when performing sparse unmixing operations.Ac-cording to the final results of the experiment,this method makes favorable performance under varying noise conditions,which is especially true under low signal to noise conditions.

关键词： hyperspectral image(HSI) nonnegative dictionary learning norm loss function unsupervised unmixing

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Multi-scale three-dimensional variational data assimilation for high-resolution aerosol observations: Methodology and application

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Science China Earth Sciences 2022年第10期65卷 1961-1971页

作者： Zengliang ZANG Yanfei liANG Wei YOU Yi li xiaobin PAN Zhijin li College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073China No.32145 Unit of PLA Xinxiang 453000China Department of Atmospheric and Oceanic Sciences Fudan UniversityShanghai 200433China Joint Institute for Regional Earth System Science and Engineering University of California Los AngelesCalifornia 91109USA

With an increasing number of air quality monitoring stations installed around the Chinese mainland,high-resolution aerosol observations become available,allowing improvements in air pollution monitoring and aerosol forecasting.However,the multi scales(especially small-scale)information included in high-resolution aerosol observations could not be effectively utilized by the traditional three-dimensional variational method(3DVAR).This study attempted to extend the traditional 3DVAR to a multi-scale 3DVAR with two iteration steps,two-scale-3DVAR(TS-3DVAR),to improve the effectiveness of assimilating high-resolution observations.In TS-3DVAR,the large-scale and small-scale components of observation information were decomposed from the original high-resolution observations using a Gaussian smoothing method and then assimilated using the corresponding large-scale or small-scale background error covariances which were derived from the partitioned background error samples.The data assimilation(DA)analysis field generated by TS-3DVAR is more accurate than 3DVAR in reproducing the field’s multi-scale characteristics,which could thus be used as the initial chemical field of the air quality model to improve aerosol forecasting.Particulate matter with an aerodynamic diameter of less than 2.5μm(PM_(2.5))and 10.0μm(PM_(10)) from the surface air quality monitoring stations from November 01 to November 30,2018 at 00:00 were assimilated daily to verify the effects of TS-3DVAR and 3DVAR on the aerosol analysis and forecast accuracy.The results showed that TS-3DVAR better constrained both large-scale and small-scale,especially the spatial wavelengths in a range of 54-216 km and those above 351 km.The average power spectra of the TS-3DVAR assimilation increment in the two wavelength ranges were 71.70%and 35.33%higher than those of 3DVAR.As a result,the TS-3DVAR was more effective than 3DVAR in improving the accuracy of the initial chemical field,and thereby the forecasting capability for PM_(2.5).In the initial chemical field,the 30-

关键词： Multi-scale 3DVAR Data assimilation Aerosol forecast WRF-Chem

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Comparison of the effects of Ti-and Si-containing minerals on goethite transformation in the Bayer digestion of goethitic bauxite

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International Journal of Minerals,Metallurgy and Materials 2023年第9期30卷 1705-1715页

作者： Guotao Zhou Yilin Wang Tiangui Qi Qiusheng Zhou Guihua liu Zhihong Peng Xiaobin Li School of Metallurgy and Environment Central South UniversityChangsha 410083China

Goethitic bauxite is a widely used raw material in the alumina industry.It is an essential prerequisite to clarify the effect of Ti-and Si-containing minerals on goethite transformation in the Bayer digestion process,which could efficiently utilize the Fe-and Al-containing minerals present in goethitic bauxite.In this work,the interactions between anatase or kaolinite with goethite during various Bayer digestion processes were investigated using X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),transmission electron microscopy (TEM),and scanning electron microscopy (SEM).The results showed that anatase and kaolinite hindered the transformation of goethite.Anatase exerted more significant effects than kaolinite due to the dense sodium titanate layer on the goethite surface after reacting with the sodium aluminate solution.Adding the reductant hydrazine hydrate could eliminate the retarding effect by inducing the transformation of goethite into magnetite.In this process,titanium was embedded into the magnetite lattice to form Ti-containing magnetite.Furthermore,the weakening of the interaction between magnetite and sodium aluminosilicate hydrate reduced the influence of kaolinite.As a validation of the above results,the reductive Bayer method resulted in the transformation of goethite into goethitic bauxite with 98.87% relative alumina digestion rate.The obtained red mud with 72.99wt% Fe2O3could be further utilized in the steel industry.This work provides a clear understanding of the transformative effects of Ti-and Si-containing minerals on iron mineral transformation and aids the comprehensive use of iron and aluminum in goethitic bauxite subjected to the reductive Bayer method.

关键词： goethite magnetite kaolinite anatase Bayer digestion

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Face stability analysis of large shield-driven tunnel in rock-soil interface composite formations

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Underground Space 2022年第6期7卷 1021-1035页

作者： xiaobin Ding Kang li Yuxuan Xie Shuzhuo liu School of Civil Engineering and Transportation South China University of TechnologyGuangzhou 510641China Guangdong Provincial Key Laboratory of Modern Civil Engineering Technology South China Institute of Geotechnical EngineeringGuangzhou 510650China

A new 3D log-spiral model(LS-M model)is proposed to determine the minimal support pressure on the tunnel face of a large shielddriven tunnel in rock-soil interface(RSI)composite formations.In the proposed LS-M model,we define the RSI angle ω and use a new approach to calculate the equivalent tunnel face area,which provides a collapse zone with more realistic geometry than the traditional wedge model.And it has acceptable accuracy with simpler implementation than limit equilibrium analysis.Comparing with previous studies and 3D numerical analysis,it indicates that:(i)the LS-M results agree well with others in full-soil formations on the variation patterns of minimum support pressure and stability coefficients N_(c) and N_(γ);(ii)the critical RSI angle ω_(cr),which is predominantly influenced by soil cohesion,increases with the soil property values;(iii)the limit support pressure starts to increase with ω only when ω>ω_(cr);(iv)the peak support pressure occurs at lower C/D with a lower ω;(v)ω can only affect stability coefficients N_(c) and N_(γ) when ω and the friction angle are relatively small,while N_(s) is substantially influenced by RSI angle ω.

关键词： Tunnel Stability limit support pressure RSI composite formations 3D failure mechanism

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Rough set based optimization method of machine tools in cloud manufacturing

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International Journal of Modeling, Simulation, and Scientific Computing 2018年第1期9卷 35-45页

作者： Song Huang Chao Yin Xiaobin Li Fei liu State Key Laboratory of Mechanical Transmission Chongqing University 174 ShazhengjieShapingba 400044ChongqingP.R.China School of Economics and Business Administration Chongqing University 174 Shazhengjie Shapingba400044ChongqingP.R.China

Cloud Manufacturing(CMfg),combining with the technologies of Cloud computing and Internet of Things,is an intelligent networked manufacturing model,which can quickly integrate various distributed manufacturing resources for collaboratively completing the complex and customized manufacturing tasks.One of the key technologies supporting this model is the optimal manufacturing resources in the CMfg systems,typically machine tools(MTs).In this paper,the attributes of MTs in cloud environment are analyzed,the constraint relationship between the attributes and the optimization criteria of MTs is established,and an optimization method of MTs based on rough set is proposed.Finally,a case study is discussed to validate the feasibility and effectiveness of the proposed method.

关键词： Cloud manufacturing machine tool resource constraint optimization

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Experimental research on aero-propulsion coupling characteristics of a distributed electric propulsion aircraft

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Chinese Journal of Aeronautics 2023年第2期36卷 201-212页

作者： Xingyu ZHANG Wei ZHANG Weilin li xiaobin ZHANG Tao LEI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Key Laboratory of Aircraft Electric Propulsion Technology Ministry of Industry and Information TechnologyXi'an 710072China School of Automation Northwestern Polytechnical UniversityXi'an 710072China

Distributed Electric Propulsion(DEP)aircraft use multiple electric motors to drive the propulsors,which gives potential benefits to aerodynamic-propulsion interaction.To investigate and quantify the aerodynamic-propulsion interaction effect of the wing section,we built a DEP demonstrator with 24"high-lift"Electric Ducted Fans(EDFs)distributed along the wing’s trailing edge.This paper explores and compares the aero-propulsion coupling characteristics under various upstream speed,throttle,and EDF mounting surface deflection angles using a series of wind tunnel tests.We compare various lift-augmentation power conditions to the clean configuration without propulsion unit under the experiment condition of 15-25 m/s freestream flow and angles of attack from-4°to 16°.The comparison of computational results to the experimental results verifies the effectiveness of the computational fluid dynamic analysis method and the modeling method for the DEP configuration.The results show that the EDFs can produce significant lift increment and drag reduction simultaneously,which is accordant with the potential benefit of Boundary Layer Ingestion(Bli)at low airspeed.

关键词： Aero-propulsion coupling Boundary layer ingestion Distributed electric propulsion Short Take-Off and Landing(STOL) Wind-tunnel experiment

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Analysis of the dynamic performance of an electro-hydrostatic actuator and improvement methods

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Chinese Journal of Aeronautics 2018年第12期31卷 2312-2320页

作者： Zhihui li Yaoxing SHANG Zongxia JIAO Yan liN Shuai WU Xiaobin Li School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China Science and Technology on Aircraft Control Laboratory Beihang UniversityBeijing 100083China

As a kind of actuation mechanism for power-by-wire(PBW) actuation systems of more/all electrical aircraft, an electro-hydrostatic actuator(EHA) is a highly integrated local hydraulic actuation system. It is a volume control system consisting of a motor, a pump, an actuator, etc.,which has features of high efficiency and reliability. However, the poor dynamic characteristic is one of the main factors restricting its wide application in aircraft. In this paper, the reason for the poor dynamic characteristic of an EHA is revealed from the perspectives of the natural frequency characteristic and the power requirement, respectively. In other words, the insufficiency of the motor output power at a high frequency is the main factor causing the poor dynamic characteristic of the system, and methods which include increasing the maximum output torque of the motor, reducing the rotational inertia of the motor-pump group, and adopting a double-motorpump group configuration are proposed in this paper, by which the dynamic characteristic of the system can be improved. The feasibility of those methods are verified by simulations. Finally, the dynamic characteristic is tested on an EHA prototype, and results show that saturation of the output torque of the motor is the main factor restricting the dynamic characteristic of the EHA system.

关键词： Dynamic characteristic Motor-pump group Power requirement Rotational inertia

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Understanding of the electrochemical behaviors of aqueous zinc-manganese batteries:Reaction processes and failure mechanisms

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Green Energy & Environment 2022年第5期7卷 858-899页

作者： Xinyu Luo Wenchao Peng Yang li Fengbao Zhang xiaobin Fan School of Chemical Engineering and Technology State Key Laboratory of Chemical EngineeringCollaborative Innovation Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China Chemistry and Chemical Engineering Guangdong Laboratory Shantou515031China

As one of the most common cathode materials for aqueous zinc-ion batteries(AZIBs),manganese oxides have the advantages of abundant reserves,low cost,and low toxicity.However,the electrochemical mechanism at the cathode of aqueous zinc-manganese batteries(AZMBs) is complicated due to different electrode materials,electrolytes and working conditions.These complicated mechanisms severely limit the research progress of AZMBs system and the design of cells with better performance.Hence,the mechanism of AZMBs currently recognized by most researchers according to the classification of the main ions involved in the faradaic reaction is introduced in the review.Then a series of reasons that affect the electrochemical behavior of the battery are summarized.Finally,the failure mechanisms of AZMBs over prolonged cycling are discussed,and the current insufficient research areas of the system are explained,along with the direction of further research being prospected.

关键词： battery manganese electrochemical

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