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Tuning heterogeneous microstructures to enhance mechanical properties of nano-TiN particle reinforced Haynes 230 composites by laser powder bed fusion

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Rare Metals 2024年第9期43卷 4548-4565页

作者： wen-jie liu Hui Li Qian-Xing Yin He-Jun Du School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China The Institute of Technological Sciences Wuhan UniversityWuhan 430072China School of Mechanical&Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

Laser powder bed fusion(LPBF)is considered to be one of the most promising additive manufacturing technologies for producing components with geometries and high geometrical precision that are unattainable by traditional *** superalloy exhibits exceptional mechanical and high-temperature performances,rendering it a prime candidate for advanced aero-engine *** the high demand for LPBF-manufactured superalloys,the superalloy is one of the materials manufactured difficultly by LPBF due to their large laser absorptivity fluctuation,poor molten pool stability and sharp temperature ***,superalloys are characterized by severe pores,undesirable coarse columnar grains and poor mechanical *** this work,the effect of nano-TiN particles on defects,molten pool characteristics and microstructure and performance of the composites were *** 4.5 wt%TiN/Haynes230 samples exhibited exceptional nanohardness and elastic modulus with maximum values reaching 5.53 GPa and 240.03 GPa,*** superior mechanical properties were attributed to the combined effects of spatter and gas pore inhibition,grain refinement and duplex nanophases ***,the stability of molten pool was enhanced,and spatter was effectively suppressed by adding nano-TiN particles,while grain refinement and columnar to equiaxed transitions were ***,the matrix exhibited a high dislocation density due to a significant hindrance of dislocation movement caused by massive nano-phases(e.g.,TiN and M_(23)C_(6)),resulting in the formation of extensive dislocation tangles and *** work offers novel insights into the role of nanoparticles reinforced superalloy composites by LPBF.

关键词： Composites Laser powder bed fusion Molten pool characteristics Microstructure Mechanical properties

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Structural evolution of mesoporous graphene/LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2) composite cathode for Li-ion battery

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Rare Metals 2021年第3期40卷 521-528页

作者： wen-jie liu Xian-Zhong Sun Xiong Zhang Chen Li Kai Wang wen wen Yan-Wei Ma Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100190China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201204China

Layered LiMO_(2)(M=Ni,Co,and Mn) is a type of promising cathode materials for high energy density and high work voltage lithium-ion ***,the poor rate performance and low power density hinder its further *** capacity fade is related to the structural transformation in the layered LiMO_(2).In this work,the structural changes of bi-material cathode composed of mesoporous graphene and layered LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM) were studied via in situ X-ray diffraction(XRD).During different C-rate charge-discharge test at the voltage range of 2.5-4.1 V,the composite cathode of NCM-graphene(NCM-G) reveals better rate performances than pure NCM *** NCM-G composite electrode displays a higher rate capability of 76.7 mAh·g^(-1) at 5 C rate,compared to the pure NCM cathode of 69.8 mAh·g^(-1)discharge *** in situ XRD results indicate that a reversible phase transition from hexagonal H1 to hexagonal H2 occurs in layered NCM material during 1 C chargedischarge *** the current increasing to 2 C/5 C,the structure of layered NCM material for both electrodes reveals few changes during charge and discharge processes,which indicates the less utilization of NCM component at high ***,the improved rate performance for bi-material electrode is attributed to the highly conductive mesoporous graphene and the synergistic effect of mesoporous graphene and NCM material.

关键词： LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM) Mesoporous graphene Bi-material In situ X-ray diffraction(XRD) Structural evolution

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Recovery of iron from copper slag via modified roasting in CO-CO2 mixed gas and magnetic separation

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Journal of Iron and Steel Research International 2020年第7期27卷 796-806页

作者： Ping-guo Jiang Jin-sheng liu Yi-yu Xiao Xiao-heng Tan wen-jie liu School of Materials Science Shanghai Dianji UniversityShanghai201306China Department of Materials Metallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou341000JiangxiChina

A novel technology,modified roasting in CO-CO2 mixed gas and magnetic separation,was presented to recover iron from copper *** effects of various parameters such as dosage of flux(CaO),gas flowrate of CO and CO2,roasting temperature,roasting time,particle size of modified slag and magnetic flux density on the oxidized modification and magnetic separation were investigated by comparison of the X-ray diffraction patterns and iron recovery *** optimum conditions for recovering iron by oxidizing roasting and magnetic separation are as follows:calcium oxide content of 25 wt.%,mixed gas flow rates of CO2 and CO of 180 and 20 mL/min,oxidizing roasting at 1323 K for 2 h,grinding the modified slag to 38.5-25.0μm and magnetic separation at 170 *** mineralogical and microstructural characteristics of modified slag revealed that the iron-bearing minerals in the copper slag were oxidized,the generated magnetite grew into large particles,and the silicate in copper slag was combined with calcium oxide to form calcium ***,the iron-bearing concentrate with an iron grade of 54.79%and iron recovery ratio of 80.14%was effectively obtained.

关键词： Copper slag CO-CO2 mixed gas Modified roasting Magnetic separation Iron recovery ratio

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Three-Dimensional Analysis of Rolling by Twin Shear Stress Yield Criterion

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Journal of Iron and Steel Research International 2006年第6期13卷 21-26页

作者： ZHAO De-wen XIE Ying-jie liu Xiang-hua WANG Guo-dong State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

Using the twin shear stress yield criterion, the surface integral of the co-line vectors, and the integration depending on upper limit, Kobayashi＇s three-dimensional velocity field of rolling was analyzed and an analytical expression of rolling torque and single force was obtained. Through redoing the same experiment of rolling pure lead as Sims, the calculated results by the above expression were compared with those of Kobayashi and Sims formulae. The results show that the twin shear stress yield criterion is available for rolling analysis and the calculated results by the new formula are a little higher than those by Kobayashi and Sims ones if the reduction ratio is less than 30%.

关键词： twin shear stress yield criterion co-line vector integral three-dimensional rolling analytical solution

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Degenerate asymmetric quantum concatenated codes for correcting biased quantum errors

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Chinese Physics B 2021年第12期30卷 206-213页

作者： Ji-Hao Fan Jun Li Han-Wu Chen wen-jie liu School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210094China School of Computer Science and Engineering Southeast UniversityNanjing 211189China School of Computer and Software Nanjing University of Information Science and TechnologyNanjing 210044China

In most practical quantum mechanical systems,quantum noise due to decoherence is highly biased towards *** quantum state suffers from phase flip noise much more seriously than from the bit flip *** this work,we construct new families of asymmetric quantum concatenated codes(AQCCs)to deal with such biased quantum *** construction is based on a novel concatenation scheme for constructing AQCCs with large asymmetries,in which classical tensor product codes and concatenated codes are utilized to correct phase flip noise and bit flip noise,*** generalize the original concatenation scheme to a more general case for better correcting degenerate ***,we focus on constructing nonbinary AQCCs that are highly *** to previous literatures,AQCCs constructed in this paper show much better parameter performance than existed ***,we design the specific encoding circuit of the *** is shown that our codes can be encoded more efficiently than standard quantum codes.

关键词： asymmetric quantum codes concatenated code quantum channel degenerate code

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Coral-like cobalt selenide/carbon nanosheet arrays attached on carbon nanofibers for high-rate sodium-ion storage

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Rare Metals 2023年第3期42卷 916-928页

作者： Jin-Zhi Hu wen-jie liu Ji-Hua Zheng Guo-Chun Li Yong-Feng Bu Fen Qiao Jia-Biao Lian Yan Zhao Institute for Energy Research School of Energy and Power EngineeringJiangsu UniversityZhenjiang 212013China College of Chemistry and Chemical Engineering Inner Mongolia UniversityHohhot 010021China

Cobalt selenide(CoSe_(2))has become a promising anode material for sodium-ion batteries(SIBs)due to its stable chemical properties,environmental friendliness,and high theoretical ***,the undesirable rate capacity and cycle stability of the anode materials largely limit its applications for SIBs due to the relatively low electronic conductivity and huge volume change during the Na+insertion/*** this study,electrostatic spinning combined with a wet chemical method is employed to synthesize coral-like composite material(CNF@c-CoSe_(2)/C),which is composed of CoSe_(2)/carbon nanosheet arrays(CoSe_(2)/C)and carbon nanofibers(CNFs).CoSe_(2)/C nanoflakes derived from metal-organic frameworks(MOFs)with high surface area and the porous structure can inhibit the pulverization and amorphization of CoSe_(2) during charge and discharge processes,thus significantly keeping the stability of the *** can limit the overgrowth of nanosheets and serve as a conductive *** to two-dimensional CoSe_(2)/C nanoflakes and pure CoSe_(2) nanoparticles,the composite can expose more active sites and effectively accelerate the diffusion of Na+,which displays enhanced rate capability(266.5 mAh·g^(-1) at 5.0 A·g^(-1))and cycling stability(268.3 mAh·g^(-1) after 100 cycles at 1.0 A·g^(-1)).Moreover,the rational preparation strategy for metal selenide-based heterostructure material presents a new way for high-performance SIB s.

关键词： Carbon nanofiber(CNF) Cobalt selenide(CoSe_(2)) Electrostatic spinning Sodium-ion storage

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Embedding partial sulfurization of iron-cobalt oxide nanoparticles into carbon nanofibers as an efficient electrode for the advanced asymmetric supercapacitor

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Tungsten 2023年第1期5卷 118-129页

作者： wen-jie liu Ming Yuan Jia-Biao Lian Guo-Chun Li Qiu-Ping Li Fen Qiao Yan Zhao Institute for Energy Research School of Energy and Power EngineeringJiangsu UniversityZhenjiang 212013China Fuzhou Medical College of Nanchang University Fuzhou 344000China College of Chemistry and Chemical Engineering Inner Mongolia UniversityHohhot 010021China

In this paper,a series of partially sulfurized iron-cobalt oxide(FCOS) nanoparticles were embedded in carbon nanofibers(FCOS@CNF) via a simple electrospinning method and followed by a hydrothermal sulfurization *** sulfurization degree of iron-cobalt oxide nanoparticles can be further controlled by tuning the hydrothermal reaction *** self-supported FCOS@CNF samples with hierarchical nanostructure can not only effectively prevent the detaching of the FCOS nanoparticles but also provide abundant electrochemical active *** used as a supercapacitor electrode,the FCOS@CNF^(-1)0 electrode presents a high specific capacitance(1039 F·g^(-1)at 1 A·g^(-1)),a good rate performance(over 69.4%of capacitance retention from 1 to 15 A·g^(-1)),and a long cycle lifespan(88.3% of capacitance retention after 4000 cycles at10 A·g^(-1)).A unique(FCOS@CNF^(-1)0//F-RGO) asymmetric supercapacitor device was assembled using the FCOS@CNF^(-1)0 sample as the positive electrode and the freeze-dried reductive graphene oxide(F-RGO) as the negative *** hybrid device exhibits excellent electrochemical properties,including a high specific capacity,a long cycle life(86% after5000 cycles at 10 A·g^(-1)),and a maximum energy density of 24.2 Wh·kg^(-1)@725.4 W·kg^(-1).

关键词： Electrospinning Carbon nanofibers Transition metal sulfur oxide Supercapacitors

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Invalidation manner and mechanism of new type NbO electrolytic capacitor anode

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Journal of Central South University of Technology 2005年第z1期12卷 18-22页

作者： LI Jian YI Dan-qing wen Jun-jie liu Hui-qun ZHONG Hui School of Materials Science and Engineering Central South University Changsha 410083 China School of Materials Science and Engineering Central South University Changsha 410083 China School of Metallurgical Science and Engineering Central South University Changsha 410083 China School of Materials Science and Engineering Central South University Changsha 410083 China School of Metallurgical Science and Engineering Central South University Changsha 410083 China

Niobium suboxide powder was pressed and sintered in vacuum into NbO electrolytic capacitor sintered anode..High voltage and constant current formation experiment was performed on NbO electrolytic capacitor anode,during which electrolyte was 0.01 % Ha PO4 solution, temperature was 90 C and current was 50 mA per gram sample. Through the relationship between anode voltage and time and scanning electron microscopy(SEM) images of invalidated anode and normal forming anode, invalidation manner and mechanism of NbO electrolytic capacitor anode were discussed. The results show that, the main invalidation manner of NbO electrolytic capacitor anode is not short circuit but open circuit, which is different to that of traditional Ta electrolytic capacitor anode. The reason of invalidation is that anode oxide film whose thickness increases gradually penetrates the "connection neck" among anode powder particles, which leads to the open circuit invalidation of anode. Compared with Ta electrolytic capacitor,NbO electrolytic capacitor has better security.

关键词： niobium suboxide NbO invalidation manner invalidation mechanism electrolytic capacitor anode

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PEM:a lightweight program memory encryption mechanism for embedded processor

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The Journal of China Universities of Posts and Telecommunications 2010年第1期17卷 77-84页

作者： HUO wen-jie,liu Zheng-lin,ZOU Xue-cheng Department of Electronics of Science and Technology,Huazhong University of Science and Technology,Wuhan 430074,China [a] Department of Electronics of Science Technology Huazhong University of Science Technology Wuhan 430074 China

Application of embedded systems is faced with multiple threats against security. To solve this problem, this article proposes a new program memory encryption mechanism （PEM） to enhance the security of embedded processor. The new mechanism encrypts all the programs via a secure cache structure. It not only caches the instructions read from the off-chip memory, but also stores the pad values used to encrypt the plaintext. It effectively accelerates encryption and reduces the performance overhead. Besides the encryption, PEM also monitors the program modifications and reset behaviors to reduce the risk of vicious tamper. The experiment indicates that PEM has an average of 2.3 % performance improvement and results in a 25.71% power reduction in the write-back stage. The new scheme offers a good balance between performance and security. It is fully practicable for embedded processor.

关键词： embedded processor memory encryption advanced encryption standard (AES) secure cache hardware protection

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Nuclear Starburst Activity in the Seyfert 2 Galaxy NGC 2273

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Chinese Journal of Astronomy and Astrophysics 2003年第3期3卷 203-211页

作者： Qiu-Sheng Gu, Lei Shi, Shi-Jun Lei, wen-Hao liu and jie-Hao Huang Department of Astronomy, Nanjing University, Nanjing 210093 qsgu@*** Department of Astronomy Nanjing University Nanjing 210093

We present spectrophotometric results of the Seyfert 2 galaxy NGC 2273. Thepresence of high-order Balmer absorption lines (H8, H9, H10) and weak equivalent widths of CaII Kλ3933, CN λ4200, G-band λ4300 and MgIb λ5173 clearly indicate recent star-forming activity inthe nuclear region. Using a simple stellar population synthesis model, we find that for the bestfit, the contributions of a power-law featureless continuum, an intermediate-age (～ 10~8 yr) and anold (> 10~9 yr) stellar population to the total light at the reference normalization wavelength are10.0%, 33.4% and 56.6%, respectively. The existence of recent starburst activity is also consistentwith its high far-infrared luminosity (log L_(FIR.)/L☉ = 9.9), its infrared color indexes[α(25,60) = ― 1.81 and α(60,100) = ― 0.79, typical values for Seyfert galaxies withcircumnuclear starburst], and its q-value (2.23, ratio of infrared to radio flux, very similar tothat of normal spirals and starburst galaxies). Byrd et al. have suggested that NGC 2273 might haveinteracted with NGC 2273B in less than 10~9 yr ago, so the starburst activity in this galaxy couldhave been triggered by tidal interaction, as indicated in recent numerical simulations.

关键词： galaxies: seyfert galaxies: starburst galaxies: stellar content

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