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Journal of Materials Science & Technology 2021年第8期67卷 127-134页

作者： Mei-jun Liu guan-jun Yang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi'an fiaotong UniversityXi’anShaanxi710049PR China

Plasma spray-physical vapor deposition(PS-PVD)has exhibited the potential ability to prepare columnar structures for advanced thermal barrier coatings(TBCs).The coating structure is nominally affected by operating parameters,but it is controlled by the type of deposition unit actually and *** order to realize the columnar structure deposited by gaseous phase units,the transition behavior of gaseous phase units to clusters must be fundamentally *** work investigated the transport process of gaseous phase units in the PS-PVD near-substrate boundary layer along with the condensation *** Monte Carlo method was used to examine the transport process and condensation behavior of gaseous phase units under different scale boundary *** results show that it is easier to form more numerous larger clusters at the edge of the plasma jet than at the *** on the understanding of the changes in deposition unit caused by the condensation of gaseous phase in the near-substrate boundary layer of PS-PVD,an outlook towards TBCs with different structures is *** it is in good agreement with the experimental data.

关键词： Condensation behavior Transport process Cluster Boundary layer PS-PVD

Epitaxial growth and cracking of highly tough 7YSZ splats by thermal spray technology

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Journal of Advanced Ceramics 2018年第1期7卷 17-29页

作者： Lin CHEN guan-jun YANG State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and Engineering Xi'an Jiaotong University

Thermally sprayed coatings are essentially layered materials and contain large numbers of lamellar pores. It is thus quite necessary to clarify the formation mechanism of lamellar pores which significantly influence coating performances. In the present study, to elaborate the formation mechanism of lamellar pores, the yttria-stabilized zirconia(ZrO_2–7 wt% Y_2O_3, 7YSZ) splats, which have high fracture toughness and tetragonal phase stability, were employed. Interestingly, anomalous epitaxial growth occurred for all deposition temperatures in spite of the extremely high cooling rate,which clearly indicated chemical bonding and complete contact at splat/substrate interface before splat cooling. However, transverse spallation substantially occurred for all deposition temperatures in spite of the high fracture toughness of 7YSZ, which revealed that the lamellar pores were from transverse cracking/spallation due to the large stress during splat cooling. Additionally, fracture mechanics analysis was carried out, and it was found that the stress arose from the constraint effect of the shrinkage of the splat by locally heated substrate with the value about 1.97 GPa. This clearly demonstrated that the stress was indeed large enough to drive transverse cracking/spallation forming lamellar pores during splat cooling. All of these contribute to understanding the essential features of lamellar bonding and further tailoring the coating structures and performance.

关键词： epitaxial growth crack patterns transverse cracking/spallation stress locally heated substrate

Solid dust induced roughening and overheating of TBC-coated superalloy

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Journal of Materials Science & Technology 2024年第13期180卷 69-79页

作者： Jia-Qi Han Mei-jun Liu Javad Mostaghimi guan-jun Yang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi'an Jiaotong UniversityXi'an 710049China Department of Mechanical and Industrial Engineering University of TorontoTorontoON M5S 3G8Canada

Thermal barrier coatings(TBC)on superalloy blade/vane enable an increase in turbine inlet temperature(TIT)and aero-engine ***,the deposition of dust on TBC significantly ablates superalloys and becomes a bottleneck for advanced engine *** paper presents a comprehensive mod-eling approach,based on an experiment involving dust deposition on a TBC-coated substrate,aimed at understanding the fundamental cause of substrate *** results show that a significant increase in surface roughness is obtained experimentally with dust *** temperature field within the TBC-substrate system is disturbed by surface ***,the film cooling is seriously *** the dust accumulated on the TBC surface also contributes to heat insulation by increas-ing the effective TBC thickness,localized overheating of the substrate occurs and then leads to ablation and premature failure of the *** elucidation of the overheating mechanism could inform the development of strategies to resist dust accumulation in advanced aero engines.

关键词： Thermal barrier coating Superalloy Dust Roughness Overheating

Boosting electromagnetic wave absorption of Ti_(3)AlC_(2) by improving effective electrical conductivity

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Journal of Advanced Ceramics 2023年第8期12卷 1533-1546页

作者： Kai-Yu Guo Lin Chen guan-jun Yang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China

Electromagnetic wave-absorbing(EMA)materials at high temperatures are limited by poor conduction loss(L_(c)).However,adding conductors simultaneously increases the conduction loss and interfacial polarization loss,leading to a conflict between impedance matching(Z_(in)/Z_(0))and electromagnetic wave *** will prevent electromagnetic waves from entering the EMA materials,finally reducing overall absorbing ***,the effective electrical conductivity(σ)is enhanced by synchronizing particle size and grain number of Ti_(3)AlC_(2) to increase the conduction loss and avoid the conflict between the impedance matching and the electromagnetic wave *** a result,the best-absorbing performance with an effective absorption bandwidth(EAB)of 4.8 GHz(10.6–15.4 GHz)at a thickness of only 1.5 mm is realized,which is the best combination of wide absorption bandwidth and small thickness,and the minimum reflection loss(RL_(min))reaches−45.6 dB at 4.1 *** short,this work explores the regulating mechanism of the EMA materials of effective electrical conductivity by simulated calculations using the Vienna ab-initio Simulation Package(VASP)and COMSOL as well as a series of experiments,which provide new insight into a rational design of materials with anisotropic electrical conductivity.

关键词： anisotropic electrical conductivity conduction loss(Lc) interfacial polarization loss(LIP) effective electrical conductivity co-optimize impedance matching(Zin/Z0) electromagnetic wave loss

ANALYSIS OF METHOD FOR DETERMINING AZIMUTH OF PRINCIPAL AXIS OF INERTIA BASED ON DYNAMIC BALANCE MEASUREMENT

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Chinese Journal of Mechanical Engineering 2006年第4期19卷 530-533页

作者： ZHAO jun guan Yingzi QI Naiming College of Astronautics Harbin Institute of Technology Harbin 150001 China

The dynamic balance quality of a rotating object is an important factor to maintain the stability and accuracy for motion. The azimuth of the principal axis of inertia is a major sign of dynamic balance. A usual method is measuring moment of inertia matrix relative to some base coordinates on a rotary inertia machine so as to calculate the azimuth of principal axis of inertia, By using the measured unbalance results on the two trimmed planes on a vertical hard bearing double-plane dynamic balancing machine, the dimension and direction of couple unbalance can be found. An azimuth angle formula for the principal axis of inertia is derived and is solved by using unbalance quantities. The experiments indicate that method based on dynamic balancing measurement is proved rational and effective and has a fine precision.

关键词： Dynamic balance machine Principal axis of inertia Azimuth

Optimal Formation Reconfiguration Control of Multiple UCAVs Using Improved Particle Swarm Optimization

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Journal of Bionic Engineering 2008年第4期5卷 340-347页

作者： Hai-bin Duan guan-jun Ma De-lin Luo School of Automation Science and Electrical Engineering Beihang University Beijing 100191 P. R. China Provincial Key Laboratory for Information Processing Technology Suzhou University Suzhou 215006 P. R. China Center for Systems and Control Xiamen University Xiamen 361005 P. R. China

Optimal formation reconfiguration control of multiple Uninhabited Combat Air Vehicles （UCAVs） is a complicated global optimum problem. Particle Swarm Optimization （PSO） is a population based stochastic optimization technique inspired by social behaviour of bird flocking or fish schooling. PSO can achieve better results in a faster, cheaper way compared with other bio-inspired computational methods, and there are few parameters to adjust in PSO. In this paper, we propose an improved PSO model for solving the optimal formation reconfiguration control problem for multiple UCAVs. Firstly, the Control Parameterization and Time Diseretization （CPTD） method is designed in detail. Then, the mutation strategy and a special mutation-escape operator are adopted in the improved PSO model to make particles explore the search space more efficiently. The proposed strategy can produce a large speed value dynamically according to the variation of the speed, which makes the algorithm explore the local and global minima thoroughly at the same time. Series experimental results demonstrate the feasibility and effectiveness of the proposed method in solving the optimal formation reconfiguration control problem for multiple UCAVs.

关键词： uninhabited combat air vehicles particle swarm optimization control parameterization and time discretization optimal formation reeonfiguration

Effects of 1-Methylcyclopropene on NO Content,NOS Activity,and H_2O_2 Content in Postharvest Suli Pears

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Agricultural Sciences in China 2011年第5期10卷 797-804页

作者： DONG Yu LIU Li-qin guan jun-feng Institute of Genetics and Physiology Hebei Academy of Agricultural and Forestry Sciences Shijiazhuang 050051 P.R.China College of Life Science Hebei Normal University Shijiazhuang 050016 P.R.China

Studies were conducted over the effects of 1-methylcycolpropene （1-MCP） treatment on postharvest life of Suli pears （Pyrus bretschneideri Rehd.） stored at room and cold temperatures on nitric oxide （NO）,nitric oxide synthase （NOS） activity,and hydrogen dioxide （H2O2）.Results showed that the 1-MCP treatment had little effect on total soluble solids （TSS） at both room and cold temperatures.1-MCP delayed softening of Suli pear fruits,decreased respiratory rate and H2O2 accumulation,and increased NO and NOS activity at room temperature storage,while the effect of cold temperature storage was relatively *** was a significant positive correlation between NOS activity and NO *** is concluded that 1-MCP had effects on endogenous NO content and accumulation of ***,H2O2 acting as a signaling molecule via regulating NO level affects the ripening and senescence of Suli pears.

关键词： pear 1-MCP NO NOS H2O2

Effects of Nitric Oxide on the Quality and Pectin Metabolism of Yali Pears During Cold Storage

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Agricultural Sciences in China 2011年第7期10卷 1125-1133页

作者： LIU Li-qin DONG Yu guan jun-feng College of Life Science Hebei Normal University Shijiazhuang 050016 P.R.China Institute of Genetics and Physiology Hebei Academy of Agricultural and Forestry Sciences Shijiazhuang 050051 P.R.China

The effect of fumigation with 10, 20, and 30 μL L-1 nitric oxide （NO） was investigated to study the effects of NO on the quality of Yali pears during cold storage. The ethylene production, composition of cell walls, and cell-wall-modifying enzyme activities were measured on fruits which were fumigated with NO （20 μL L-1）. The results showed that NO not only reduced the peak value of ethylene production rate, the soluble sugar, soluble solid content, maintained higher firmness, starch, and NO content, but also retarded the degradation of covalent soluble pectin, accumulation of ionic soluble pectin and water soluble pectin. Moreover, NO fumigation decreased the activities of polygalacturonase （PG） and b-galactosidase（b-Gal） and delayed the peak of PG activity of fruits. Therefore, it indicated that NO fumigation could delay the softening and ripening of Yali pears.

关键词： pear nitric oxide cell wall material fruit softening

Construction and Application of Cloud Computing Model for Reciprocal and Collaborative Knowledge Management

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Computers, Materials & Continua 2023年第4期75卷 1119-1137页

作者： Jingqi Li Yijie Bian jun guan Lu Yang Business School Hohai UniversityNanjing211100China Network and Information Technology Center Hohai UniversityNanjing210098China

Promoting the co-constructing and sharing of organizational knowledge and improving organizational performance have always been the core research subject of knowledge *** research focuses on the construction of knowledge management systems and knowledge sharing and transfer *** the rapid development and application of cloud computing and big data technology,knowledge management is faced with many problems,such as how to combine with the new generation of information technology,how to achieve integration with organizational business processes,and so *** solve such problems,this paper proposes a reciprocal collaborative knowledge management model(RCKMmodel)based on cloud computing technology,reciprocity theory,and collaboration *** model includes project group management and cloud computing technology,which can realize management,finance,communication,and quality assurance of multiple projects and solve the problem of business integration with knowledge *** paper designs evaluation methods of tacit knowledge and reciprocity preference based on the Bayesian formula and analyzes their effect with simulation *** methods can provide quantitative support for the integration of knowledge management and business management to realize reciprocity and collaboration in the RCKM *** research found that RCKM model can fully use cloud computing technology to promote the integration of knowledge management and organizational business,and the evaluation method based on the Bayesian formula can provide relatively accurate data support for the evaluation and selection of project team members.

关键词： Cloud computing knowledge management tacit knowledge reciprocal preference

Effect of substrate materials on rutile crystalline orientation in plasma-sprayed TiO2 coatings

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中国有色金属学会会刊：英文版 2004年第z1期14卷 62-66页

作者： YANG guan-jun LI Chang-jiu WANG Yu-yue State Key Laboratory for Mechanical Behavior of Materials Xi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of Materials Xi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of Materials Xi''an Jiaotong University Xi''an 710049 China

TiO2 coatings are of technical importance owing to their promising applications to photocatalytical, electrical, optical and tribological coatings. Thermal spraying process has been widely used to deposit both metallic and nonmetallic coatings. During thermal spraying, spray particle at fully or partially melted condition is projected to a substrate and subsequently flattens, rapidly cools and solidifies. Therefore, a coating in lamellar structure is usually formed as a quenched microstructure. TiO2 coatings were deposited on different substrates through plasma spraying with fused-crushed powder in rutile phase as feedstock to reveal the crystalline orientation in the coatings. XRD results show that the coatings consist of rutile phase with a fraction of anatase phase, and the rutile phase presents a preferable crystalline orientation along [101] direction. It is found that the orientation factors of rutile phase in the thin coatings are significantly influenced by substrate materials. The thick coatings yield the same orientation factors of 0.22 to 0.23 on all substrates in spite of substrate materials. It is considered that the thermal properties of substrate materials are the dominant factors for the preferable crystalline orientation in rutile phase within plasmasprayed TiO2 coating.

关键词： titanium oxide thermal spray coatings rutile orientation