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High pyrolysis temperature biochar reduced the transport of petroleum degradation bacteria Corynebacterium variabile HRJ4 in porous media

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Journal of Environmental Sciences 2021年第2期33卷 228-239页

作者： Saisai Guo Xiaomei Liu hang Zhao Lan wang Jingchun Tang College of Environmental Science and Engineering Nankai UniversityTianjin 300350China Key Laboratory of Pollution Processes and Environmental Criteria(Ministry of Education) Tianijin 300350China Tianjin Engineering Research Center of Enuironmental Diagnosis and Contamination Remediation Tianjin 300350China

Biochar has been widely applied for the remediation of petroleum-contaminated ***,the effect of biochar on the transport of petroleum degradation bacteria has not been studied.A typical Gram-positive petroleum degradation bacteria-Corynebacterium variabile HRJ4 was used to study the effect of different biochars on bacterial transport and *** indicated that the addition of biochar in sand was effective for reducing the transport of bacteria and poplar sawdust biochar(PSBC)had a stronger hinder effect than corn straw biochar(CSBC).The hindrance was more evident with pyrolysis temperature of biochar raised from 300℃ to 600℃,which was attributed to the increase of specific surface area(309 times).The hindrance effect also enhanced with higher application rate of ***,the reduction of HRJ4 transport was more obvious in higher(25 mmol/L)concentration of Na Cl solution owing to electrostatic attraction *** adsorption of biochar to HRJ4 was defined to contribute to the hindrance of HRJ4 transport *** the influence of feedstocks and pyrolysis temperature on HRJ4 transport,it suggested that specific surface area had the greatest effect on HRJ4 transport,and pore-filling,electrostatic force also contributed to HRJ4 retained in quartz sand *** last,phenol transportation experiment indicated that the restriction of biochar on HRJ4 enhanced the phenol removal rate in the *** study provides a theoretical basis for the interaction of biochar and bacteria,which is vital for the remediation of oil-contaminated soil and groundwater in the field.

关键词： Gram-positive bacteria Feedstocks HRJ4 Transport Retention

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Synergistic Effects of Aluminum Hypophosphite on Intumescent Flame Retardant Polypropylene System

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Chinese Journal of Polymer Science 2015年第2期33卷 318-328页

作者： Miao-jun Xu Jing wang Yue-hang Ding 李斌 Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials College of ScienceNortheast Forestry University

The effects of aluminum hypophosphite（AHP） as a synergistic agent on the flame retardancy and thermal degradation behavior of intumescent flame retardant polypropylene composites（PP/IFR） containing ammonium polyphosphate（APP） and triazine charring-foaming agent（CFA） were investigated by limiting oxygen index（LOI）, UL-94 measurement, thermogravimetric analysis（TGA）, cone calorimeter test（CONE）, scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）. It was found that the combination of IFR with AHP exhibited an evident synergistic effect and enhanced the flame retardant efficiency for PP matrix. The specimens with the thickness of 0.8 mm can pass UL-94 V-0 rating and the LOI value reaches 33.5% based on the total loading of flame retardant of 24 wt%, and the optimum mass fraction of AHP/IFR is 1：6. The TGA data revealed that AHP could change the degradation behavior of IFR and PP/IFR system, enhance the thermal stability of the IFR and PP/IFR systems at high temperatures and promote the char residue formation. The CONE results revealed that IFR/AHP blends can efficiently reduce the combustion parameters of PP, such as heat release rate（HRR）, total heat release（THR）, smoke production rate（SPR） and so on. The morphological structures of char residue demonstrated that AHP is of benefit to the formation of a more compact and homogeneous char layer on the materials surface during burning. The analysis of XPS indicates that AHP may promote the formation of sufficient char on the materials surface and improve the flame retardant properties.

关键词： Synergistic effect Intumescent flame retardant Aluminum hypophosphite Thermal degradation Polypropylene

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Prior austenite grain boundary recognition in martensite microstructure based on deep learning

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Journal of Iron and Steel Research International 2023年第5期30卷 1050-1056页

作者： Xuan-dong wang Nan Li hang Su Hui-min Meng Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Department of Structural Steel Central Iron and Steel Research Institute Co.Ltd.Beijing 100081China Material Digital R&D Center China Iron&Steel Research Institute Group Co.Ltd.Beijing 100081China Central Laboratory Central Iron and Steel Research Institute Co.Ltd.Beijing 100081China

Grain size determination is essential in producing and testing iron and steel *** size determination of martensitic steels usually requires etching with picric acid to reveal the prior austenite grain ***,picric acid is toxic and explosive and belongs to hazardous chemicals,which makes it difficult for laboratories and testing institutions to obtain.A new experimental method was developed to use Nital etchant instead of picric *** deep learning method was used to recognize the prior austenite grain boundaries in the etched martensite microstructure,and the grain size could be determined according to the recognition ***,the polished martensite specimen was etched twice with Nital etchant and picric acid,respectively,and the same position was observed using an optical *** images of the martensitic structure and its prior austenite grain boundary label were obtained,and a data set was ***,based on this data set,a convolutional neural network model with a semantic segmentation function was trained,and the accuracy rate of the test set was 87.53%.Finally,according to the recognition results of the model,the grain size rating can be automatically determined or provide a reference for experimenters,and the difference between the automatic determination results and the measured results is about 0.5 level.

关键词： Prior austenite grain boundary Microstructure etching Image recognition Deep learning

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Null Controllability of Some Degenerate Wave Equations

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Journal of Systems Science & Complexity 2017年第5期30卷 1027-1041页

作者： Zhang Muming GAO hang School of Mathematics and Statistics Northeast Normal UniversityChangchun 130024China.

This paper is devoted to a study of the null controllability problems for one-dimensional linear degenerate wave equations through a boundary controller. First, the well-posedness of linear degenerate wave equations is discussed. Then the null controllability of some degenerate wave equations is established, when a control acts on the non-degenerate boundary. Different from the known controllability results in the case that a control acts on the degenerate boundary, any initial value in state space is controllable in this case. Also, an explicit expression for the controllability time is given. Furthermore, a counterexample on the controllability is given for some other degenerate wave equations.

关键词： Controllability degenerate wave equation Fourier expansion observability.

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Profiling the antibiotic resistome in soils between pristine and human-affected sites on the Tibetan Plateau

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Journal of Environmental Sciences 2022年第1期34卷 442-451页

作者： hang wang Xiaoxuan Su Jianqiang Su Yongguan Zhu Kai Ding Key Lab of Urban Environment and Health Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Yunnan Key Laboratory of Plateau Wetland Conservation Restoration and Ecological ServicesSouthwest Forestry UniversityKunming 650224China National Plateau Wetlands Research Center Southwest Forestry UniversityKunming 650224China

With increasing pressure from anthropogenic activity in pristine environments,the comprehensive profiling of antibiotic resistance genes(ARGs)is essential to evaluate the potential risks from human-induced antibiotic resistance in these under-studied ***,we characterized the microbial resistome in relatively pristine soil samples collected from four distinct habitats on the Tibetan Plateau,using a Smart chip based high-throughput q PCR *** compared these to soils from the same habitats that had been subjected to various anthropogenic activities,including residential sewage discharge,animal farming,atmospheric deposition,and tourism *** to pristine samples,an average of23.7%more ARGs were detected in the human-affected soils,and the ARGs enriched in these soils mainly encoded resistances to aminoglycoside and *** the four habitats studied,soils subjected to animal farming showed the highest risks of ARG enrichment and *** shown,the number of ARGs enriched(a total of 42),their fold changes(17.6 fold on average),and the co-occurrence complexity between ARGs and mobile genetic elements were all the highest in fecal-polluted *** well as antibiotics themselves,heavy metals also influenced ARG distributional patterns in Tibetan ***,compared to urban areas,the Tibetan Plateau had a low potential for ARG selection and exhibited low carriage of ARGs by mobile genetic elements,even in environments impacted by humans,suggesting that these ARGs have a limited capacity to *** present study examined the effects of multiple anthropogenic activities on the soil resistomes in relatively pristine environments.

关键词： Antibiotic resistance gene Resistome risk Tibetan plateau Animal farming Anthropogenic activity

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Novel wavelet-homotopy Galerkin technique for analysis of lid-driven cavity flow and heat transfer with non-uniform boundary conditions

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Applied Mathematics and Mechanics(English Edition) 2018年第12期39卷 1691-1718页

作者： Qiang YU hang XU Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE) State Key Laboratory of Ocean Engineering School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University

In this paper, a brand-new wavelet-homotopy Galerkin technique is developed to solve nonlinear ordinary or partial differential equations. Before this investigation,few studies have been done for handling nonlinear problems with non-uniform boundary conditions by means of the wavelet Galerkin technique, especially in the field of fluid mechanics and heat transfer. The lid-driven cavity flow and heat transfer are illustrated as a typical example to verify the validity and correctness of this proposed technique. The cavity is subject to the upper and lower walls’ motions in the same or opposite *** inclined angle of the square cavity is from 0 to π/2. Four different modes including uniform, linear, exponential, and sinusoidal heating are considered on the top and bottom walls, respectively, while the left and right walls are thermally isolated and stationary.A parametric analysis of heating distribution between upper and lower walls including the amplitude ratio from 0 to 1 and the phase deviation from 0 to 2π is conducted. The governing equations are non-dimensionalized in terms of the stream function-vorticity formulation and the temperature distribution function and then solved analytically subject to various boundary conditions. Comparisons with previous publications are given,showing high efficiency and great feasibility of the proposed technique.

关键词： wavelet-homotopy Galerkin technique mixed boundary condition liddriven inclined cavity non-uniform heat transfer

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A numerical study of segmented cooling-stream injection in supersonic film cooling

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Chinese Journal of Aeronautics 2022年第6期35卷 156-171页

作者： hang NI Mingjun wang Peixue JIANG Wei PENG Yinhai ZHU Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China School of Nuclear Science and Technology Xi’an Jiaotong UniversityXi’an 710049China Department of Energy and Power Engineering Key Laboratory for Thermal Science and Power Engineering of Ministry of EducationTsinghua UniversityBeijing 100084China Tsinghua University-Zhang Jiagang Joint Institute for Hydrogen Energy and Lithium-Ion Battery Technology Tsinghua UniversityBeijing 100084China

The present study proposes a segmented cooling-stream injection structure based on a certain coolant mass flow rate,and numerically investigates the effect of segmented cooling-stream injection on supersonic film *** results indicate that without shock-wave impingement and with helium as the coolant,segmented cooling-stream injection can reduce the mixing between the mainstream and the cooling stream to produce better cooling performance than single injection,especially at larger coolant Mach ***,with nitrogen as the coolant,the cooling effect of the segmented-injection system is very close to that of the single-injection *** at the impinging region is enhanced significantly when there is an incident shock *** the shock wave impinges between the two coolant inlets,segmented cooling-stream injection improves film cooling effectiveness in the midstream and downstream regions more than single injection because only part of the cooling stream undergoes the enhanced mixing effect of the shock *** advantage of segmented injection is reduced when the impinging region is behind the second coolant *** further downstream the impinging region,the smaller the associated advantage.

关键词： Film cooling Mach number Segmented injection Shock wave Supersonic flow

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Phase equilibria in Ti-rich portion and thermodynamic re-optimization of Co-Ti system

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Journal of Iron and Steel Research International 2022年第6期29卷 914-924页

作者： Hua-kou Yang Chen-yang Zhou hang wang Bin Yang Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000JiangxiChina Jiangxi Advanced Copper Industry Research Institute Yingtan 335000JiangxiChina

The experimental and thermodynamic studies of the Co-Ti system are an important part of the project to build a thermodynamic database for multicomponent Co-Ti-based *** key alloys were prepared and then examined for microstructural,compositional and thermal analyses to determine the Ti-rich phase *** to the available experimental information,the Co-Ti system was thermodynamically re-optimized on the basis of CALPHAD *** disordered solutions,liquid,fcc-A1(α-Co),bcc-A2(β-Ti)and hcp-A3(ε-Co andα-Ti)were modeled as substitutional ***_(2)with limited solubility was treated as a stoichiometric compound,whileγ-Co_(2)Ti andβ-Co_(2)Ti with certain solubility were described in the form of(Co,Ti)2(Co,Ti)1 using a two-sublattice model.A single Gibbs energy function was employed to model two order–disorder transformations from fcc-A1 to fcc-L12(Co3Ti)and from bcc-A2 to bcc-B2(CoTi).A group of self-consistent thermodynamic parameters of the Co-Ti system were *** these thermodynamic parameters,the experimental data can be described more reasonably and satisfactorily.

关键词： Co-based superalloy Co-Ti system Phase equilibrium CALPHAD method Order–disorder transformation

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Design of multilayer cellular neural network based on memristor crossbar and its application to edge detection

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Journal of Systems Engineering and Electronics 2023年第3期34卷 641-649页

作者： YU Yongbin TANG Haowen FENG Xiao wang Xiangxiang HUANG hang School of Information and software Engineering University of Electronic Science and Technology of ChinaChengdu 610054China

Memristor with memory properties can be applied to connection points(synapses)between cells in a cellular neural network(CNN).This paper highlights memristor crossbar-based multilayer CNN(MCM-CNN)and its application to edge *** MCM-CNN is designed by adopting a memristor crossbar composed of a pair of ***-CNN based on the memristor crossbar with changeable weight is suitable for edge detection of a binary image and a color image considering its characteristics of programmablization and *** of merit(FOM)is introduced to evaluate the proposed structure and several traditional edge detection operators for edge detection *** results show that the FOM of MCM-CNN is three times more than that of the traditional edge detection operators.

关键词： edge detection figure of merit(FOM) memristor crossbar synaptic circuit memristor crossbar-based cellular neural network(MCM-CNN)

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Error modeling and compensating of a novel 6-DOF aeroengine rotor docking equipment

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Chinese Journal of Aeronautics 2022年第6期35卷 312-324页

作者： Tianyi ZHOU hang GAO Xuanping wang Lun LI Qing LIU Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian 116024China AECC Shenyang Liming Aero-engine Co. LtdChina

In the docking process of aeroengine rotor parts,docking accuracy that indicates the gaps between the end faces is strictly required.A key issue is improving docking accuracy using automated docking *** this paper,a systematic study is carried out on the error modeling and compensation of a novel six-degrees-of-freedom(6-DOF)docking equipment for aeroengine ***,a new model for indicating the main indexes of docking accuracy is ***,the error model of a specially designed 6-DOF docking equipment is established based on a modified Denavit Hartenberg method with five ***,two error compensation methods are *** on the above models,a docking accuracy simulation algorithm is proposed using the Monte Carlo ***,verification experiments are *** results show that,for the maximum values and standard deviations of the gaps between the rotor end-faces in the actual and target positions and attitudes,i.e.,main indexes that represent docking accuracy,the deviation rates between the simulation and experimental results are less than20%.The modeling methods have referential *** decline rates of these values are 50–65%when using the two proposed compensation *** compensation methods significantly improve the docking accuracy.

关键词： Accuracy analysis Aeroengine rotor Docking Error compensation Error models Multi-degree-of-freedom structures

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