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Phase Stability of Residual Austenite in 60Si2Mn Steels Treated by Quenching and Partitioning

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Journal of Iron and Steel Research International 2011年第2期18卷 70-74页

作者： li yang Key Laboratory for liquid Solid Structural Evolution and Processing of Materials of Ministry of Education Shandong University Jinan 250061 Shandong China School of Materials Science and Engineering Shandong University Jinan 250061 Shandong China

The residual austenite and its stability in commercial 60Si2Mn steel treated by quenching and partitioning （Q-P） were investigated. The Q-P heat treatment was carried out using a system of ordinary electric furnace--oil bath box--electric furnace. Cryogenic treatments at different temperatures were performed to assess the thermal stability of residual austenite. The microstructure, particularly residual austenite, was analyzed using optical microscope and X-ray diffraction （XRD）, and the microhardness and Rockwell hardness were measured. The residual austenite with the volume fraction as much as 13.7% and the HRC hardness level of 41 were achieved, and the residual austenite is relatively stable.

关键词： 60Si2Mn steel quenching partitioning microstructure phase stability

Stochastic Variational Inference-Based Parallel and Online Supervised Topic Model for Large-Scale Text Processing

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Journal of Computer Science & Technology 2018年第5期33卷 1007-1022页

作者： yang li Wen-Zhuo Song Bo yang College of Computer Science and Technology Jilin University Changchun 130012 China Key Laboratory of Symbolic Computation and Knowledge Engineering Ministry of Education Jilin University Changchun 130012 China Aviation University of Air Force Changchun 130062 China

Topic modeling is a mainstream and effective technology to deal with text data, with wide applications in text analysis, natural language, personalized recommendation, computer vision, etc. Among all the known topic models, supervised Latent Dirichlet Allocation （sLDA） is acknowledged as a popular and competitive supervised topic model. How- ever, the gradual increase of the scale of datasets makes sLDA more and more inefficient and time-consuming, and limits its applications in a very narrow range. To solve it, a parallel online sLDA, named PO-sLDA （Parallel and Online sLDA）, is proposed in this study. It uses the stochastic variational inference as the learning method to make the training procedure more rapid and efficient, and a parallel computing mechanism implemented via the MapReduce framework is proposed to promote the capacity of cloud computing and big data processing. The online training capacity supported by PO-sLDA expands the application scope of this approach, making it instrumental for real-life applications with high real-time demand. The validation using two datasets with different sizes shows that the proposed approach has the comparative accuracy as the sLDA and can efficiently accelerate the training procedure. Moreover, its good convergence and online training capacity make it lucrative for the large-scale text data analyzing and processing.

关键词： topic modeling, large-scale text classification, stochastic variational inference, cloud computing online learning

Inhomogeneous Distribution of Second Phase Particles in Grain Oriented Electrical Steels

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Journal of Materials Science & Technology 2011年第12期27卷 1120-1124页

作者： yang li Weimin Mao Ping yang Department of Materials University of Science and Technology Beijing Beijing 100083 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing100083 China

The second phase particles were observed during the whole manufacturing process of conventional grain oriented electrical steels, exhibiting that the areal density of particles in the center was obviously higher than that on the surface at each manufacturing stage. After hot rolling, the approximately equiaxed grains formed upon recrystallization were present on the sheet surface while the deformation structures were retained in the central part. Thus, the dislocation density on the surface was evidently lower than that in the center and this trend became more noticeable after the first cold rolling. Since new precipitates were mainly nucleated at dislocations during both hot rolling and annealing following cold deformation, the difference in dislocation density resulted in the inhomogeneous distribution of particles through the thickness of sheet. According to this, Goss grains, which were usually found near the surface, tended to grow up more easily during the secondary recrystallization treatment.

关键词： Grain oriented electrical steel Precipitation Recrystallization Dislocation

Research on the applications of infrared technique in the diagnosis and prediction of diesel engine exhaust fault

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Journal of Thermal Science 2011年第2期20卷 189-194页

作者： Lv Shi-gui yang li yang Qian Department of Power Engineering Naval University of Engineering Wuhan 430033 China

This paper mainly introduces the basic principles,the methods and the applications of infrared technique in the diagnosis and prediction of diesel engine exhaust faults. The test-bed for monitoring diesel engine exhaust faults by thermal infrared imager has been designed. In different running conditions, the exterior surface radiation temperatures of the exhaust pipe of the 6135G-1 diesel engine have been measured by infrared imaging system. According to the principle of infrared temperature measurement, the real temperatures of the exterior surface of the exhaust pipe have been calculated. Based on the principle of heat transfer, the method of calculating the exhaust temperatures according to the exterior surface radiation temperatures of exhaust pipe measured by thermal infrared imager is built. The relationship between diesel engine exhaust temperatures and faults has been analyzed. It is shown that the application of infrared inspection and diagnosis to the identifying of diesel engine exhaust faults is feasible and effective.

关键词： infrared exhaust temperature infrared diagnosis diesel engine fault

Synthesis Mechanism and Material Characterization of C4AF Obtained by the Self-propagating Combustion Reaction Method

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Journal of Wuhan University of Technology(Materials Science) 2018年第5期33卷 1099-1107页

作者： HE Zhen li yang Shaanxi Key Laboratory of Safety and Durability of Concrete Structure Xoing UniversityXi＇an 710123China State Key Laboratory of Water Resources ＆ Hydropower Engineering Science Wuhan UniversityWuhan 430072China

To investigate the influence of preparation process on the properties of synthesized C4AF,the powder was prepared via the self-propagating combustion reaction（SPCR）method using urea as fuel and metal nitrates as cation *** mechanism of the SPCR method,calculation and adjusting principles of urea dosage were detailedly *** characterization of synthesized C4AF was performed with the aid of X-ray diffractometry,Fourier transform infrared spectrometry,scanning electron microscopy,energydispersive X-ray spectroscopy,^27Al nuclear magnetic resonance and isothermal microcalorimetric *** content of transition phase of calcium carbonate in synthesized C4AF was determined by quantitative analysis of X-ray *** was found that there was no difference in the hydration behavior of C4AF synthesized by the SPCR method and the traditional solid-state reaction（SSR）method.C3AH6 and amorphous iron（III）hydroxide（Fe（OH）3）would be formed during the hydration of C4AF while CH *** size of synthesized C4AF was 16.1 A and the apparent activation energy was 36.2 kJ/*** condition of Al in C4AF can be detected by ^27Al NMR technique,but the peaks were broadened and the intensities were relatively low,supporting the use of ^27Al NMR for the quantitative analysis of C3A in Portland cements.

关键词： C4AF self-propagating SPCR urea ^27Al NMR apparent activation energy

A collaborative strategy for enhanced reduction of Cr(Ⅵ) by Fe(0) in the presence of oxalate under sunlight:Performance and mechanism

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Journal of Environmental Sciences 2020年第4期32卷 385-394页

作者： Qi Zhou yang li Heng yang Yun Gao College of Chemistry and Chemical Engineering Anhui UniversityHefei 230601China Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control School of Environmental Science and EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China Chengdu Integrated Testing Center of Rocks and Ores Sichuan Geology and Mineral Exploration and Development BureauChengdu 610081China Anhui Electric Power Construction Second Engineering Co.Ltd. China Energy Construction GroupHefei 230000China

Nanometer-size zero-valent iron(NZVI)is an efficient reducing agent,but its surface is easily passivated with an oxide layer,leading to reaction *** our study,oxalate(OA)was introduced into this heterogeneous system of NZVI,which could form ferrioxalate complexes with the NZVI surface-bound Fe3+and dissolved Fe3+in the *** of ferrioxalate complexes can facilitate the generation of Fe2+from Fe3+and CO2·-radical,both species have strong reduction ***,a"photo-oxalate-Fe(0)"system through sunlight induction was established,which not only prohibited the formation of a surface passivation layer,but also displayed a synergetic mechanism of ferrioxalate photolysis to enhance reduction,exhibiting remarkably higher degradation activity(several times faster)toward the model pollutant Cr(Ⅵ)than the mechanism with NZVI *** tests suggested that both NZVI dosage and OA content markedly affected the reduction *** pH was beneficial to the reduction ***,recyclability experiment showed that the reduction rate decreased from 0.21706 to 0.03977 min-1 after three cycles of reuse due to the NZVI losing reaction activity generally,but the system still maintained considerable reduction ***,a mechanism was revealed whereby NZVI would transform to Fe oxides after the exhaustion of its reductive power,and the photolysis of ferrioxalate to promote the cycling of iron species played the predominant role in providing extra reduction *** features confirm that introduction of OA into Cr(Ⅵ)reduction by NZVI through sunlight induction is advantageous and promising.

关键词： Nanometer-size zero-valent iron Oxalate Sun irradiation Photolysis of ferrioxalate Cycling of surface iron Synergetic mechanism

Three-dimensional steady-state closed form solution for multilayered fluid-saturated anisotropic finite media due to surface/internal point source

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Applied Mathematics and Mechanics(English Edition) 2021年第1期42卷 17-38页

作者： lianzhi yang Fanmin HE yang li Zhiyong SONG School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Chengdu Surveying Geotechnical Research Institute Co. Ltd.of China Metallurgical Group CorporationChengdu 610023China Department of Aerospace Science and Technology Space Engineering UniversityBeijing 101416China

A three-dimensional(3 D)steady-state solution of fluid saturated anisotropic finite media is *** eigenequation method and the pseudo-Stroh formalism are used to obtain the exact solution for homogeneous saturated finite *** propagator matrix method is introduced to deal with the corresponding multilayered poroelastic *** poroelastic solutions due to surface or internal point fluid source are *** comparison of the results of the saturated isotropic media in a half space and those obtained by the finite element method is given to illustrate the accuracy of the solution in a finite *** solutions of a sandwich poroelastic medium are presented to analyze its hydromechanical *** ratios of the horizontal permeability to vertical permeability and different source positions are *** results show that the fluid parameters and source positions have great influence on the hydromechanical behaviors of the layered media.

关键词： poroelastic pseudo-Stroh formalism multilayered point fluid source

2D interspace confined growth of ultrathin MoS_(2)-intercalated graphite hetero-layers for high-rate li/K storage

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Nano Research 2021年第4期14卷 1061-1068页

作者： yang li Song Jiang Yong Qian Xuedong Yan Jie Zhou Zheng Yi Ning lin Yitai Qian Department of Applied Chemistry University of Science and Technology ofChinciy Hefei 230026China Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China College of Chemical Engineering Ningbo PolytechnicNingbo 315800China Ningbo Veken Battery Co.Ltd Ningbo 315800China

Herein,a two-dimensional(2D)interspace-confined synthetic strategy is developed for producing MoS_(2)intercalated graphite(G-MoS_(2))hetero-layers composite through sulfuring the pre-synthesized stage-1 MoCI5-graphite intercalation compound(M0 CI5-GIC).The in situ grown MoS_(2)nanosheets(3-7 layers)are evenly encapsulated in graphite layers with intimate interface thus forming layer-by-layer MoS_(2)-intercalated graphite *** this structure,the unique merits of MoS_(2)and graphite components are integrated,such as high capacity contribution of MoS_(2)and the flexibility of graphite ***,the tight interfacial interaction between hetero-layers optimizes the potential of conductive graphite layers as matrix for MoS_(2).As a result,the G-MoS_(2)exhibits a high reversible li+storage of 344 mAh·g^(-1)even at 10 A·g^(-1)and a capacity of 539.9 mAh·g^(-1)after 1,500 cycles at 5 A·g^(-1).As for potassium ion battery,G-MoS_(2)delivers a reversible capacity of 377.0 mAh·g^(-1)at 0.1 A·g^(-1)and 141.2 mAh·g^(-1)even at 2 A·g^(-1).Detailed experiments and density functional theory calculation demonstrate the existence of hetero-layers enhances the diffusion rates of li^(+)and K^(+).This graphite interspace-confined synthetic methodology would provide new ideas for preparing function-integrated materials in energy storage and conversion,catalysis or other fields.

关键词： interspace-confined MoS_(2)-intercalated graphite hetero-layers li^(+)storage potassium ion battery

Preliminary Investigation of Preparing High Burn-Up Structure in Nuclear Fuel by Flash Sintering Using CeO_(2) as a Surrogate

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Acta Metallurgica Sinica(English Letters) 2021年第12期34卷 1758-1768页

作者： Tongye li Jing yang Chong Yu Yihan liang yang li Xinfang Zhang Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610023China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

The high burn-up structure(HBS)is characterized by the grain size of 100-300 nm and a porosity of up to 20%,which is formed at the rim of the nuclear fuel pellet due to 2-3 times higher local burn-up during the in-pile *** is considered a new potential structure for high-performance ***,it is difficult to prepare HBS by conventional sintering *** this study,flash sintering was used to prepare HBS using CeO_(2)as a surrogate for a preliminary investigation.A new experimental configuration for rapid sintering of CeO_(2)pellets was provided,in which the green body can be rapidly preheated and pressure-assisted by the induction heating *** insulated quartz tube was used as the die for the flash sintered samples,allowing the current to flow through the sample and providing a stable condition for applying an external pressure of approximately 5.3-7.0 MPa during flash sintering *** an initial electric field of 141 V cm-1 and holding for 1-7 min at the maximum current density of~98 mA mm^(-2),CeO_(2)ceramics with a grain size of 114-282 nm and a relative density of 75.4-99.7%were *** densification and microstructure evolution behaviors during flash sintering in this new experimental configuration have been discussed in *** new experimental configuration may provide a promising approach for preparing UO_(2)ceramics and their HBS.

关键词： High burn-up structure,Flash sintering,CeO_(2)ceramic,Grain growth