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lASER ClADDED TiCN COATINGS ON THE SURFACE OF TITANIUM

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Acta Metallurgica Sinica(English letters) 2007年第3期20卷 210-216页

作者： y.l. yang D. Zhang H.S. Kou C. S. liu College of Science Northeastern University Shenyang 110004 China College of Material and Metallurgy Northeastern University Shenyang 110004 China

laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs （OM）. The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm/s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm^-2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2 and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80μm, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.

关键词： laser cladding TiCN coating titanium

RESEARCH ON INFlUENCE OF TEMPERATURE ON A PRECISION FORGING PROCESS OF BlADE WITH A TENON

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Acta Metallurgica Sinica(English letters) 2005年第6期18卷 749-755页

作者： y.l. liu H. yang T. Gao M. Zhan W. Cai College of Materials Science and Engineering Northwestern Polytechnical University Xi＇an 710072 China

The blade precision forging process is a forming process with high temperature and large plastic deformation. Interaction of deformation and heat conduction leads to large uneven distribution of temperature. The unevenness of temperature distribution has a great effect on mechanical properties and the microstracture of materials. So it is necessary to consider the influence of temperature on the precision forging process of blades. Taking a blade with a tenon into consideration, a 3D mechanical model in precision forging is built up. The distribution laws of temperature field and the influence of the temperature on the equivalem stress in the process are obtained by using 3-D coupled thermo-mechanical FEM code developed by the authors Theresuits obtained illustrate that the influence of the temperature field on the blade forging process is considerable. The achievements of predicting microstructure and mechanical properties for forged blades is significant.

关键词： blade with a tenon precision forging equivalent stress field,temperature field thermo-mechanical coupled 3D FEM simulation

Sequence assembly using next generation sequencing data —challenges and solutions

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Science China(life Sciences) 2014年第11期57卷 1140-1148页

作者： CHIN Francis y.l. lEUNG Henry C.M. yIU S.M. Department of Computer Science The University of Hong Kong

Sequence assembling is an important step for bioinformatics *** the help of next generation sequencing(NGS)technology,high throughput DNA fragment(reads)can be randomly sampled from DNA or RNA molecular ***,as the positions of reads being sampled are unknown,assembling process is required for combining overlapped reads to reconstruct the original DNA or RNA *** with traditional Sanger sequencing methods,although the throughput of NGS reads increases,the read length is shorter and the error rate is *** introduces several problems in ***,paired-end reads instead of single-end reads can be sampled which contain more *** existing assemblers cannot fully utilize this information and fails to assemble longer *** this article,we will revisit the major problems of assembling NGS reads on genomic,transcriptomic,metagenomic and metatranscriptomic *** will also describe our IDBA package for solving these *** package has adopted several novel ideas in assembling,including using multiple k,local assembling and progressive depth *** with existence assemblers,IDBA has better performance on many simulated and real sequencing datasets.

关键词： genomic assembling de Bruijn graph paired-end reads next generation sequencing

Application of artificial neural networks for predicting the impact of rolling dynamic compaction using dynamic cone penetrometer test results

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第2期9卷 340-349页

作者： R.A.T.M. Ranasinghe M.B. Jaksa y.l. Kuo F. Pooya Nejad School of Civil Environmental and Mining EngineeringUniversity of AdelaideAdelaideAustralia

Rolling dynamic compaction(RDC),which involves the towing of a noncircular module,is now widespread and accepted among many other soil compaction ***,to date,there is no accurate method for reliable prediction of the densification of soil and the extent of ground improvement by means of *** study presents the application of artificial neural networks(ANNs) for a priori prediction of the effectiveness of *** models are trained with in situ dynamic cone penetration(DCP) test data obtained from previous civil projects associated with the 4-sided impact *** predictions from the ANN models are in good agreement with the measured field data,as indicated by the model correlation coefficient of approximately *** is concluded that the ANN models developed in this study can be successfully employed to provide more accurate prediction of the performance of the RDC on a range of soil types.

关键词： Rolling dynamic compaction(RDC) Ground improvement Artificial neural network(ANN) Dynamic cone penetration(DCP) test

Effect of two-step cooling process on mechanical properties of TRIP steel with high performance

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Journal of Iron and Steel Research International 2018年第4期25卷 426-432页

作者： M.l. li H. Jiang y.l. He l.B. Chen G.T. Zhang H. Wang X.G. lu l. li School of Materials Science and Engineering Shanghai University Shanghai 200072 China State Key.l.boratory of Advanced Special Steel Shanghai University Shanghai 200072 China Pangang Group Research Institute Panzhihua 617000 Sichuan China

A novel two-step cooling experiment was established to simulate the slow cooling process of continuous annealing production line for transformation-induced plasticity （TRIP） steel. The microstructures and mechanical properties of TRIP steel soaked at 700℃ for different time were investigated by tensile test, scanning electron microscopy, X-ray diffraction, and thermodynamic and kinetic calculation. It is shown that the steel soaked for 15 s exhibits the optimal product of strength and elongation （PSE 〉 30,000 MPa%） due to the transformation of austenite to proeutectoid ferrite, which delays the bainite transformation and improves the stability of retained austenite. In addition, the mechanical properties of TRIP steel soaked over 30 s are much lower, resulting from the precipitation of cementite, which decreases the stability of retained austenite and weakens the TRIP effect.

关键词： Transformation induced plasticity steel Two-step cooling Microstructure Mechanical property

Superplasticity of Ti2448 Alloy with Nanostructured Grains

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Journal of Materials Science & Technology 2011年第12期27卷 1099-1104页

作者： M.J. Xiao y.X. Tian G. W. Mao S.J. li y.l. Hao R. yang School of Astronautics Northwestern Polytecllnic University Xi＇an 710072 China - Shenyang National laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Ti-24Nb-4Zr-8Sn, abbreviated as Ti2448 from its chemical composition in weight percent, is a multifunctional /3 type titanium alloy with body centered cubic （bcc） crystal structure, and its highly.l.calized plastic deformation behavior contributes significantly to grain refinement during conventional cold processing. In the paper, the nanostructured （NS） alloy with grain size less than 50 nm produced by cold rolling has been used to investigate its superplastic deformation behavior by uniaxial tensile tests at initial strain rates of 1.5 ×10-2, 1.5×10^-3 and 1.6×10-4 s-1 and temperatures of 600,650 and 700℃. The results show that, in comparison with the coarse-grained alloy with size of 50 μm, the NS alloy has better superplasticity with elongation up to ～275% and ultimate strength of 50-100 MPa. Strain rate sensitivity （m） of the NS alloy is 0.21, 0.30 and 0.29 for 600,650 and 700℃, respectively. These results demonstrate that grain refinement is a valid way to enhance the superplasticity of Ti2448 alloy.

关键词： Titanium alloy bcc crystal Superplasticity Nanostructured grain

Cortical hem signaling center: functions, development, and potential implications for evolution and brain disorders

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Neural Regeneration Research 2025年第4期20卷 1079-1080页

作者： Victor V.Chizhikov Igor y.Iskusnykh Department of Anatomy and Neurobiology University of Tennessee Health Science CenterMemphisTNUSA

Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical *** such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in *** cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)*** cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).

关键词： epithelium Figure center

Bilayer expurgated lDPC codes with uncoded relaying

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Digital Communications and Networks 2017年第3期3卷 176-179页

作者： Md. Noor-A-Rahim Nan Zhang Sk. Md. Rabiul Islam y.l. Guan Centre for Infocomm Technology (INFINITUS) Nanyang Technological University Singapore Institute for TelecommunicationsResearch University of South Australia Adelaide Australia Dept.of Eleetronics and Communication Engineering Khulna University of Engineering & Technology Bangladesh

Bilayer low-density parity-check （lDPC） codes are an effective coding technique for decode-and-forward relaying, where the relay forwards extra parity bits to help the destination to decode the source bits correctly. In the existing bilayer coding scheme, these parity bits are protected by an error correcting code and assumed reliably available at the receiver. We propose an uneoded relaying scheme, where the extra parity bits are forwarded to the destination without any protection. Through density evolution analysis and simulation results, we show that our proposed scheme achieves better performance in terms of bit erasure probability than the existing relaying scheme. In addition, our proposed scheme results in lower complexity at the relay.

关键词： Bilayer codes lDPC codes Density evolution Decode-and-forward relaying

DIFFUSION　PHENOMENA　AND　MICROSTRUCTURE　STABIlITy　OF　Ni－Cr－Al－y－Si　COATING　ON　THENi_3Al　BASED　AllOy　SUBSTRATE

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Acta Metallurgica Sinica(English letters) 1996年第6期9卷 635-639页

作者： Z.P. Xing y.F. Han y.l. Ji and M.G. yan(Beijing Institute of Aeronautical Materials, Beijing 100095, ) Beijing Inst of Aeronautical Materials Beijing China

In this paper, Ni-Cr-Al-y-Si coating deposited by vacuum are deposition on the Ni_3Alalloy IC6, the typical use of which is for turbine blades and vanes, was *** results of the tests show that the tensile properties at room temperature and stress rupture properties at 1100℃ of the IC6 alloy were not obviously influenced by the coatings. At annealing state, limited element interdiffusion was observed. After stress rupture testing for 252 h at 1100℃/90 MPa, however,significant interdiffusion of Mo, Cr and Al took place between the coating layer and the *** element diffustion did not result in the formation of brittle phases on the coating/substrate interface. No cracking and spallation in the coating were *** it can be concluded that the Ni-Cr-Al-y-Si overlay coating was successful for protecting the IC6 alloy.

关键词： M-Cr-Al-y coating Ni_3Al based alloy microstructure stability vskip 0.6cm