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Preparation of microporous mullite refractories with high strength based on low-grade bauxite and coal gangue

INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY 2024年第3期21卷 1648-1657页

作者： chen, fuwen Sang, Shaobai Ma, Yuzhou Li, Yawei Wuhan Univ Sci & Technol State Key Lab Refractories & Met Wuhan 430081 Peoples R China Natl Provincal Joint Engn Res Ctr High Temp Mat & Wuhan Peoples R China

For the energy-saving and safe utilization of industrial furnaces, it is essential to develop refractories with low thermal conductivity and high strength. In this study, low-grade bauxite and coal gangue were used as the main raw materials to prepare microporous mullite refractories with low thermal conductivity and high strength by the in situ decomposition method. The effect of coal gangue content and sintering temperature on the structure and properties of mullite refractories was also investigated. The results show that the average pore size of mullite refractories containing coal gangue is between 1.3 and 4.4 mu m;with the addition of coal gangue, the apparent porosity of mullite refractories increases and their thermal conductivity decreases. Coal gangue reduces the number of pores larger than 14 mu m, improves the microstructure uniformity of mullite refractories, and increases their cold compressive strength. The strength of microporous refractory treated at 1500 degrees C containing 36.2% coal gangue as raw material is up to (105.6 +/- 1.7 MPa);and its thermal conductivity tested at 1000 degrees C is only .442 W/(m K)).

关键词： coal gangue low-grade bauxite mullite strength thermal conductivity

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Phase transformation sequence and kinetics of ω formation in Ti-3573 titanium alloy during continuous heating

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JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T 2024年 29卷 1642-1649页

作者： Gao, chenjiong chen, fuwen Xu, Guanglong Cui, Yuwen Nanjing Tech Univ Coll Mat Sci & Engn Nanjing 210009 Peoples R China

The work explores the phase transformation sequence and the kinetics of omega formation in a novel metastable beta titanium alloy of Ti-3Al-5Mo-7V-3Cr (wt%) through dilatometer test and phase/microstructure characterizations. The phase transformation sequence has been identified as beta -> beta + omega, beta + omega -> alpha + beta, beta -> beta + alpha, and alpha -> beta during the continuous heating. The formation of omega phase has underwent nucleation and growth stages revealed by the S-shaped kinetic curve. The diffusion controlled mechanism has been analyzed via Avrami exponent. The average activation energy for beta -> beta + omega phase transformation has been evaluated 90.42 kJ/mol via Kissinger-Akahira-Sunose equation. The activation energy difference between early and late stages of omega formation has been compared among metastable beta titanium alloys. The small value of Ti -3573 alloy may imply a thermo-kinetic inconvenience of omega assisted alpha formation.

关键词： Ti-3573 Dilatometry Phase transformation sequence Kinetics

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MM-Tap: Adaptive and Scalable Tap Localization on Ubiquitous Surfaces With mm-Level Accuracy

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IEEE INTERNET OF THINGS JOURNAL 2023年第23期10卷 20789-20802页

作者： Huang, Yandao Li, Cong chen, fuwen Zhang, Qian Wu, Kaishun Hong Kong Univ Sci & Technol Dept Comp Sci & Engn Hong Kong Peoples R China Hong Kong Univ Sci & Technol Guangzhou IoT Thrust Informat Hub Guangzhou 511466 Peoples R China Shenzhen Univ Coll Comp Sci & Software Engn Shenzhen 518060 Peoples R China Hong Kong Univ Sci & Technol Guangzhou Informat Hub DSA Guangzhou 511466 Peoples R China

Transforming physical surfaces into virtual interfaces can extend the interaction capability of many exciting metaverse applications in the future. Recent advances in vibration-based tap sensing show promise for this vision using passive vibration signals. However, current approaches based on Time-Difference-of-Arrival (TDoA) triangulation suffer the impact of fluctuant wave velocity due to the dispersive and heterogeneous nature of solid mediums, failing to meet the performance requirement for practical use. In this article, we present MM-Tap, a vibration-based tap localization system that can transform ubiquitous surfaces into virtual touch screens with low overhead. A novel localization scheme is proposed based on the finding of spatiotemporal mapping between tap locations and TDoA values, which pushes the accuracy limits of vibration-based tap sensing from unstable cm-level to mm-level. We investigate the geometry of the sensor layout and design a model-based method to synthesize tap data, which enables MM-Tap to adapt to various surface materials and respond to arbitrary sensing scales after a few seconds of calibration. We combine MM-Tap with a COTS projector and facilitate a digitally augmented surface where users can play video games with low latency.

关键词： Human-computer interaction localization tap sensing vibration-based sensing

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Microstructural strengthening and toughening mechanisms in Fe-containing Ti-6Al-4V:A comparison between homogenization and aging treated states

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Journal of Materials Science & Technology 2022年第4期99卷 114-126页

作者： Yu Liao Junhua Bai fuwen chen Guanglong Xu Yuwen Cui Tech Institute for Advanced Materials&College of Materials Science and Engineering Nanjing Tech UniversityNanjing 211816China

Microalloying of Ti–6Al–4V alloy by Fe addition has attracted interest as a promising way to improve castability and comprehensive mechanical *** mission of this work is twofold by employing the experimental examination and the phenomenological analysis,(1)to investigate the effect of Fe addition on the microstructure features and mechanical properties of the Fe-containing Ti–6Al–4V(TC4-xF)alloys subjected to casting and homogenization treatment,and(2)to unveil the critical microstructure features in homogenization,hot-worked and aging treated alloys,respectively,that benefit the yield strength and the fracture *** observations evidence that the addition of 0.5 wt.%Fe is most effective in enhancing the tensile ductility and the modeⅠfracture *** Fe addition up to 0.7–0.9 wt.%results in plateau values of yield and ultimate strengths with some *** analyses screen out the microstructural strengthening and toughening determinants which exhibit distinct sensitivities on Fe content under different processing *** solid solution strengthening is confirmed as the primary effect that governs the yield strength of the homogenization treated TC4-xF alloys,followed by the refined size of colony andαlamella,so does it for the hot-worked and the aging-treated *** strengthening effect of Fe could be further promoted by hot-working but impaired by a prolonged annealing time or a lowered cooling *** type of crack propagation path and theαmorphology are discerned to play their own leading roles in different cases to influence the performance of fracture toughness.A long crack propagation distance that traverses broadα/βlamellae embraces a high crack propagation resistance and gives rise to enhanced fracture *** experimental results enrich the dataset of microstructure features and mechanical properties of Ti–6Al–4V relevant *** upon the phenomenological analysis,the discove

关键词： Ti-6Al-4V Fe microalloying Homogenization Yield strength Fracture toughness Microstructural strengthening/toughening factors

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Application of fuzzy spiking neural dP systems in energy coordinated control of multi-microgrid

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JOURNAL OF MEMBRANE COMPUTING 2023年第1期5卷 69-80页

作者： Yu, Wenping Xiao, Xiangquan Wu, Jieping chen, fuwen Zheng, Li Zhang, Huijie Chengdu Technol Univ Sch Automation & Elect Engn Chengdu 611730 Peoples R China Sichuan Univ Coll Elect & Informat Engn Chengdu 610065 Peoples R China

To achieve carbon peaking and carbon neutrality goals, the research on technologies related to the grid connection of high proportion renewable energy has become a hot spot. Multi-microgrid is a feasible solution, only by ensuring the safe and stable operation of the multi-microgrid system can the advantages of the multi-microgrid be brought into full play. Different from other membrane systems, spiking neural dP systems can solve input problems in a distributed manner, making it suitable for the control field. First, to ensure the stable operation of the multi-microgrid, this paper introduces the fuzzy theory into the spiking neural dP systems and proposes fuzzy spiking neural dP systems (FSNdPS). The improved P system can better solve the problems of uncertainty and inaccuracy contained in the multi-microgrid information caused by the high proportion of new energy access. Second, the proposed FSNdPS are used to model the coordinated control of a typical multi-microgrid structure, and the corresponding coordinated control strategy is proposed. Finally, the correctness and feasibility of the proposed method are verified by a reasoning test and MATLAB simulation, and the safe and stable operation of multi-microgrid is realized.

关键词： Spiking neural dP systems Fuzzy theory Multi-microgrid Coordinated control

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Rapper: A Parameter-Aware Repair-in-Memory Accelerator for Blockchain Storage Platform 30

Rapper: A Parameter-Aware Repair-in-Memory Accelerator for B...

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30th IEEE International Symposium on High-Performance Computer Architecture (HPCA)

作者： Ma, chenlin Wang, Yingping chen, fuwen Liao, Jing Wang, Yi Mao, Rui Shenzhen Univ Coll Comp Sci & Software Engn Shenzhen Peoples R China

ISBN: (纸本)9798350393132;9798350393149

Blockchain storage platforms reward storage nodes for keeping user-uploaded data for a certain amount of time. These storage nodes are unstable and can go online or offline unpredictably at any time, leading to potential data loss. To prevent data loss, blockchain storage platforms adopt erasure codes on user-uploaded encrypted data. Data repair processes will be performed to recover the lost data. However, the data repair processes heavily rely on time-consuming erasure coding algorithms, mainly consisting of vector-matrix multiplications. The emerging processing-in-memory technique can efficiently speed up the processing of vector-matrix multiplications. It can be integrated into blockchain storage platforms to solve the data repair issue. This paper presents Rapper, a parameter-aware repair-inmemory accelerator for blockchain storage platforms. Rapper utilizes the computing power of emerging processing-in-memory architecture so that data repair processes can be processed in a parallel manner and the overall efficiency can be improved significantly. Specifically, at the hardware level, the ReRAM memory is reorganized into our proposed double bank, XRU, XGroup, and ReRAM crossbars structure. At the software level, a parallel decoding/encoding strategy is proposed to fully exploit the internal parallelism of ReRAM. We also propose an adaptive parameter-aware mapping to handle various sizes of stripes. To demonstrate the viability of the proposed technique, a representative blockchain storage project Storj is adopted as the default storage infrastructure. Experimental results show that Rapper can achieve a 1.96x speedup on average compared to the representative scheme.

关键词： Accelerator Blockchain Storage Data Repair Erasure Coding Processing-in-memory

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Development of an Optimized Three-Axis Fast Tool Servo for Ultraprecision Cutting

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IEEE-ASME TRANSACTIONS ON MECHATRONICS 2022年第5期27卷 3244-3254页

作者： chen, Yuan-Liu Li, Zhongwei chen, fuwen Lin, Huanbin Ju, Bing-Feng Liu, Yi Zhejiang Univ State Key Lab Fluid Power & Mechatron Syst Hangzhou 310058 Peoples R China Zhejiang Univ Ningbo Inst Technol Hangzhou 310058 Peoples R China

A three-axis fast tool servo (FTS) with a symmetric structure design to reduce the parasitic motion for realizing high tracking accuracy while maintaining high performances in stiffness and open-loop bandwidth is developed for ultraprecision diamond cutting. Modeling, analysis, and optimization of performances by the finite-element method in six degree-of-freedom are conducted for designing the mechanism. Experiments are carried out to test the performances of the three-axis FTS, which show low parasitic motion, high tracking accuracy, and high dynamic response. With the low tracking error of close-loop control for each axis, complicated trajectory tracking in 3-D space is realized with a tracking error as small as 5 nm. Finally, complicated and irregular microstructures are fabricated by the three-axis FTS to demonstrate the practicability of the FTS.

关键词： Compliant mechanism fast tool servo (FTS) motion decoupling parasitic motion ultraprecision cutting

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Classified dataset, regression and machine learning modeling for prediction of phase transformation temperatures in steels

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CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY 2024年 87卷

作者： Lu, Jinlei Xu, Guanglong chen, fuwen Cui, Yuwen Nanjing Tech Univ Sino Spain Joint Lab Biomed Mat S2LBM Nanjing Peoples R China Nanjing Tech Univ Coll Mat Sci & Engn Nanjing Peoples R China

The prediction of the characteristic Martensite Start (M-s) temperature and Austenitic Nose Tip Temperature (ANTT) in steels is of scientific and technological importance;however, it faces significant challenges due to multiphysical complexity. In this study, we introduced a structured framework for data classification and hierarchical iterations aimed at predicting M-s (Martensite start temperature) and ANTT (Austenite non-transforming temperature). This framework was incorporated into two optimization models, leading to enhancements in accuracy, extrapolation capabilities, and generalization performance. First, we classified the collected M-s datasets hierarchically based on the alloying elements presented in steels, including carbon, austenite stabilizers, non-austenitization elements, and data credibility. Regression analyses of M-s temperatures concerning chemical compositions were then carried out using phenomenological variables from binary systems to multi-component systems in alignment with the spirit of CALPHAD modeling, which is renowned for its robust extrapolation abilities. By iteratively fitting the hierarchically classified datasets and implementing hierarchical iterations, we developed the CALPHAD-guided phenomenological variable (CGPV) M-s regression model. This model achieved improved accuracy levels, with R-2 values of 0.9 for training and 0.87 for testing, surpassing most conventional regression models that do not account for compositional interactions. Furthermore, the CALPHAD-guided machine learning (CGML) model, constructed based on the classified datasets and hierarchical iterations but without utilizing phenomenological variables, demonstrated strong performance with R-2 values of 0.98 and 0.86 for training and testing, respectively. The CGML model was demonstrated not only to reliably filter out problematic data in a dataset but also to unveil the unnoticed coupling between carbon and other alloying elements on M-s. Finally, the CGML metho

关键词： Machine learning CALPHAD guided dimension hierarchy Classified dataset Steels Martensite start temperature Austenitic nose tip temperature

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Mapping of microstructure features and micromechanical properties of Ti-xAl-yFe (x=0-6, y=4-10 wt.%) alloys via diffusion couple method

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JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T 2022年 18卷 3526-3540页

作者： Liu, Yaohua Wang, Hai Zhu, Shuaishuai Wang, Jiang Xu, Guanglong chen, fuwen Cui, Yuwen Nanjing Tech Univ Tech Inst Adv Mat Nanjing 210009 Peoples R China Nanjing Tech Univ Coll Mat Sci & Engn Nanjing 210009 Peoples R China Nanjing Inst Technol Sch Mat Sci & Engn Nanjing 211167 Peoples R China Guilin Univ Elect Technol Guangxi Key Lab Informat Mat Guilin 541004 Peoples R China

In this work, a diffusion couple of Ti-6Al-4Fe/Ti-10Fe (wt. %) was fabricated and heat-treated under BASCA (beta-annealing, slow cooling, and aging) processing conditions to facilitate the strengthening and toughening design for low-cost titanium alloys. Assisted by Scanning Electron Microscopy (SEM), Electron Probe Micro analyses (EPMA), and nano-indentation, a picture was constructed to map the composition-dependent microstructure features and micromechanical properties in the composition array of Ti-(0-6)Al-(10-4)Fe (wt. %). The reduction of Al and the enrichment of Fe resulted in the a lamellae in finer appearance and less amount, indicating that the alloys with the same chemical composition as that in the micro-areas would show similar microstructure features. The elastic modulus E obtained from nanoindentation exhibited a decreasing trend with Al impoverishment which was in contrast to a slight increase of nanohardness H. The measured elastic modulus and nanohardness enabled evaluations of wear resistance (H/E), resistance to plastic deformation (H-3/E-2), elastic recovery rate (U-e/U-t), and plasticity index (U-p/U-t) in the micro-areas which served as the property indices analogous to those of the independent alloys with the same chemical compositions. The indices varied monotonously in the composition array. The highest H/E, H-3/E-2, U-e/U-t and the lowest U-p/U-t was discovered at Ti-10Fe terminal, indicating good wear resistance and longer service potentials. Nevertheless, the high modulus E = 145.76 GPa of Ti-4.96Al-4.43Fe is promising in the ballistic application. (C) 2022 The Authors. Published by Elsevier B.V.

关键词： Diffusion couple Ti-xAl-yFe Nanohardness Elastic modulus Microstructural and micromechanical properties

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Phase transformation and microstructure evolution of Ti6Al4V-0.55Fe alloy with different initial microstructure during continuous heating

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JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T 2022年 18卷 1704-1716页

作者： Li, Xin Zhu, Qisong Liu, Sinong Li, Feng chen, fuwen Wang, Hui Chang, Hui Nanjing Tech Univ Coll Mat Sci & Engn Nanjing 210009 Peoples R China Nanjing Tech Univ Tech Inst Adv Mat Nanjing 210009 Peoples R China Univ Sci & Technol Beijing State Key Lab Adv Met & Mat Beijing 100083 Peoples R China

The phase transformation during continuous heating of Ti6Al4V-0.55Fe alloy with various initial microstructure including equiaxed, duplex and lamellar microstructures was investigated by thermal expansion test. The results illuminate that the 13/a phase transition curves of the three samples all present the sigmoidal "S" shape, which proves that this process is controlled by nucleation and growth. The activation energies and Avrami indexes of phase transformation were obtained by Kissinger-Achaia-Sunose (KAS) method and Kolmogorov-Johnson-Mehl-Avrami (KJMA) model. The average activation energies of the phase transitions in the three samples with initial equiaxed, duplex and lamellar microstructures are 163.9, 194.4 and 231.5 kJ/mol, respectively. The result implies that the phase transition is more likely to occur in equiaxed microstructure, which is consistent with the results of sigmoidal "S" shaped curves. Besides, the phase transition mechanism of samples with different initial microstructures presents three different stages, including nucleation and diffusion of crystals, diffusion phase transition, and meaningless numerical interval. Furthermore, the microstructure evolutions of the three samples were analyzed by thermal expansion method at a heating rate of 5 K$min = 1. The phase transformation is divided into three stages: lamellar a mainly merges into thicker a phase, thick a transforms into 13 phase and finally equiaxed a transforms into 13 phase. The layered a occurs obvious coarsening first and then redissolution phenomena during the a phase transition. The difference in the morphology, size and composition of layered a and primary equiaxed a can affect the phase transformation behavior of the alloy during the heating process. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC

关键词： Ti6Al4V-0 55Fe alloy Phase transformation Microstructure evolution Initial microstructure

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