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Structural engineering of hard carbon through spark plasma sintering for enhanced sodium-ion storage

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Rare Metals 2024年第9期43卷 4274-4285页

作者： Hao-Ming Xiao Heng Zheng Ping Yuan Jun-Hui Luo Lin-Lin Shen Jie-Feng Tan Xian-You Luo De Li Yong Chen Guangdong Key Laboratory for Hydrogen Energy technologies School of Materials Science and Hydrogen EnergyFoshan University State Key Laboratory of Marine Resource Utilization in South China Sea Hainan Provincial Key Laboratory of Research on Utilization of Si-Zr-Ti ResourcesHainan University

Hard carbon （HC） has emerged as one of the superior anode materials for sodium-ion batteries （SIBs）,with its electrochemical performance significantly influenced by the presence of oxygen functional groups and its closed pore ***,current research on the structural adjustment of these oxygen functional groups and the closed pore architecture within HC remains ***,energy-efficient and contamination-free spark plasma sintering technology was employed to tune the structure of coconut-shell HC,resulting in significant adjustments to the content of carboxyl （decreasing from 5.71 at%to 2.12 at%） and hydroxyl groups （decreasing from 7.73 at % to 6.26 at%）.Crucially,these modifications reduced the irreversible reaction of oxygen functional groups with Na+.Simultaneously,a substantial number of closed pores with an average diameter of 1.22 nm were generated within the HC,offering an ideal environment for efficient Na+*** structural changes resulted in a remarkable improvement in the electrochemical performance of the modified *** reversible specific capacity of the modified HC surged from 73.89 mAh·g-1to an impressive 251.97 m Ah·g-1at a current density of 50 mA·*** at 400 mA·g-1,the reversible specific capacity increased significantly from 14.55 to 85.44 mAh·***,this study provides a novel perspective for designing tailored HC materials with the potential to develop high-performance SIBs.

关键词： Closed pores Hard carbon Oxygen functional groups Sodium-ion batteries Spark plasma sintering

Experimental Study on the Electrochemical Performance of PEMFC under Different Assembly Forces

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 265-274页

作者： Tongze Su Jiaran Liu Yanqiang Wei Yihuizi Li Weichao Luo Jinzhu Tan Nanjing tech University Nanjing 211816China

Proton exchange membrane fuel cell(PEMFC)is of paramount significance to the development of clean *** components of PEMFC are assembled using many pairs of nuts and *** assembly champing bolt torque is critical to the electrochemical performance and mechanical stability of *** this paper,a PEMFC with the threechannel serpentine flow field was used and *** different assembly clamping bolt torques were applied to the PEMFC in three uniform assembly bolt torque and six non-uniform assembly bolt torque conditions,*** then,the electrochemical performance experiments were performed to study the effect of the assembly bolt torque on the electrochemical *** test results show that the assembly bolt torque significantly affected the electrochemical performance of the *** uniform assembly bolt torque conditions,the maximal power density increased initially as the assembly bolt torque increased,and then decreased on further increasing the assembly *** existed the optimum assembly torque which was found to be 3.0 N·m in this *** non-uniform assembly clamping bolt torque conditions,the optimum electrochemical performance appeared in the condition where the assembly torque of each bolt was closer to be 3.0 N·*** could be due to the change of the contact resistance between the gas diffusion layer and bipolar plate and mass transport resistance for the hydrogen and oxygen towards the catalyst *** work could optimize the assembly force conditions and provide useful information for the practical PEMFC stack assembly.

关键词： Proton exchange membrane fuel cell Assembly force Experiment Electrochemical performance

Transferable adversarial slow feature extraction network for few-shot quality prediction in coal-to-ethylene glycol process

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Chinese Journal of Chemical Engineering 2024年第7期71卷 258-271页

作者： Cheng Yang Chao Jiang Guo Yu Jun Li Cuimei Bo School of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing 211816China Department of Intelligent Manufacturing Nanjing Tech UniversityNanjing 210009China

In the coal-to-ethylene glycol(CTEG)process,precisely estimating quality variables is crucial for process monitoring,optimization,and control.A significant challenge in this regard is relying on offline laboratory analysis to obtain these variables,which often incurs substantial monetary costs and significant time *** resulting few-shot learning scenarios present a hurdle to the efficient development of predictive *** address this issue,our study introduces the transferable adversarial slow feature extraction network(TASF-Net),an innovative approach designed specifically for few-shot quality prediction in the CTEG ***-Net uniquely integrates the slowness principle with a deep Bayesian framework,effectively capturing the nonlinear and inertial characteristics of the CTEG ***,the model employs a variable attention mechanism to identify quality-related input variables adaptively at each time step.A key strength of TASF-Net lies in its ability to navigate the complex measurement noise,outliers,and system interference typical in CTEG *** learning strategy using a min-max game is adopted to improve its robustness and ability to model irregular industrial data accurately and ***,an incremental refining transfer learning framework is designed to further improve few-shot prediction performance achieved by transferring knowledge from the pretrained model on the source domain to the target *** effectiveness and superiority of TASF-Net have been empirically validated using a real-world CTEG *** with some state-of-the-art methods,TASF-Net demonstrates exceptional capability in addressing the intricate challenges for few-shot quality prediction in the CTEG process.

关键词： Chemical process Neural networks Slowness principle Transfer learning Prediction

Improved nuclear mass formula with an additional term from the Fermi gas model

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Nuclear Science and techniques 2024年第5期35卷 131-138页

作者： Xiao-Yu Xu Li Deng Ai-Xi Chen Hang Yang Amir Jalili Han-Kui Wang School of Science Zhejiang Sci-Tech UniversityHangzhou 310018China

Nuclear mass is a fundamental property of nuclear physics and a necessary input in nuclear *** to the complexity of atomic nuclei and nonperturbative strong interactions,conventional physical models cannot completely describe nuclear binding *** this study,the mass formula was improved by considering an additional term from the Fermi gas *** nuclear masses in the Atomic Mass Evaluation Database were reproduced with a root-mean-square deviation(RMSD)of -1.86 MeV(1.92 MeV).The new mass formula exhibits good performance in the neutron-rich nuclear *** RMSD decreases to 0.393 MeV when the ratio of the neutron number to the proton number is≥1.6.

关键词： Nuclear mass formula Neutron-rich nuclei Fermi-gas model

Generating synthetic as-built additive manufacturing surface topography using progressive growing generative adversarial networks

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Friction 2024年第6期12卷 1283-1298页

作者： Junhyeon SEO Prahalada RAO Bart RAEYMAEKERS Department of Mechanical Engineering Virginia TechBlacksburgVA 24061USA Grado Department of Industrial and Systems Engineering Virginia TechBlacksburgVA 24061USA

Numerically generating synthetic surface topography that closely resembles the features and characteristics of experimental surface topography measurements reduces the need to perform these intricate and costly ***,existing algorithms to numerically generated surface topography are not well-suited to create the specific characteristics and geometric features of as-built surfaces that result from laser powder bed fusion(LPBF),such as partially melted metal particles,porosity,laser scan lines,and ***,we present a method to generate synthetic as-built LPBF surface topography maps using a progressively growing generative adversarial *** qualitatively and quantitatively demonstrate good agreement between synthetic and experimental as-built LPBF surface topography maps using areal and deterministic surface topography parameters,radially averaged power spectral density,and material ratio *** ability to accurately generate synthetic as-built LPBF surface topography maps reduces the experimental burden of performing a large number of surface topography ***,it facilitates combining experimental measurements with synthetic surface topography maps to create large data-sets that facilitate,*** as-built surface topography to LPBF process parameters,or implementing digital surface twins to monitor complex end-use LPBF parts,amongst other applications.

关键词： additive manufacturing surface topography synthetic surface topography generative adversarial networks

Highly efficient and active Co-N-C catalysts for oxygen reduction and Zn-air batteries

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Frontiers in Energy 2024年第4期18卷 436-446页

作者： Cong LEI Rongzhong YANG Jianan ZHAO Wenbin TANG Fadong MIAO Qinghong HUANG Yuping WU School of Energy Science and Engineering Nanjing Tech UniversityNanjing 211816China

In this study,the Lewis doping approach of polyaniline(PANI)was employed to fabricate cobait-nitrogen-carbon(Co-N-C)oxygen electrocatalysts for Zn-air batteries,aiming to enhance the active spots of *** resulting Co-N-C catalysts exhibited welldefined nanofiber networks,and the Brunauer-EmmettTeller(BET)analysis confirmed their substantial specific surface *** experiments demonstrated that the Co-N-C catalysts achieved the half-wave potential(***)of 0.85 V in alkaline medium,overcoming Pt/C and iron-nitrogen-carbon(Fe-N-C)counterparts in extended cycle testing with only a 25 mV change in a half-wave potential after 5000 ***,the highest power density measured in the zinc(Zn)-air battery reached 227 mW/cm2,a significant improvement over the performance of 101 mW/cm2 of the platinum on activated carbon(Pt/C)*** findings highlight the advantageous stability enhancement associated with the utilization of Co in the Co-N-C catalysts.

关键词： oxygen reduction reaction(ORR) oxygen evolution reaction(OER) non-noble metal catalysts Co-N-C catalysts Zn-air battery

Enhanced bright green luminescence from GdOF:Ho^(3+) up-conversion phosphor via Yb^(3+) doping

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Journal of Rare Earths 2024年第2期42卷 263-269,I0002页

作者： Linjun Qin Yue Guo Jing Xu Lixi Wang Qitu Zhang College of Materials Science and Engineering Nanjing Tech UniversityNanjing211816China

In this paper,a series of GdOF-based green phosphors doped with Ho^(3+) and Yb^(3+) ions was prepared by a simple co-precipitation *** crystal structure s and optical prope rties were investigated in *** intensity of the emission of GdOF:Yb^(3+),Ho^(3+) phosphors is enhanced by the effective energy transfer from Yb^(3+) to Ho^(3+),and the optimal luminescence is achieved with the Ho^(3+)doping amount of 0.1 mol%as well as Yb^(3+) doping amount of 5 mol%.Tunable UC emission of samples is achieved by adjusting the doping concentration of Ho^(3+) or Yb^(3+).The purity of the green UC emission is further improved by enhancing the excitation pumping *** addition,logarithmic functions of green,red and nearinfrared radiation intensities were calculated versus logarithmic function of pump power for further study.A possible UC luminescence mechanism between Yb^(3+) and Ho^(3+) is discussed based on powerdependent UC luminescence spectrum and decay *** results suggest that GdOF:Yb^(3+),Ho^(3+)phosphors with bright and high-purity green UC emission have potential applications in the fields of bioimaging,display and illumination.

关键词： Up-conversion GdOF Lanthanide ions Rare earths

Harmonic balance simulation of the influence of component uniformity and reliability on the performance of a Josephson traveling wave parametric amplifier

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Chinese Physics B 2024年第4期33卷 339-343页

作者：郑煜臻熊康林冯加贵杨辉 School of Nano-tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026China Suzhou Institute of Nano-tech and Nano-Bionics Chinese Academy of SciencesSuzhou 215123China

A Josephson traveling wave parametric amplifier(JTWPA),which is a quantum-limited amplifier with high gain and large bandwidth,is the core device of large-scale measurement and control systems for quantum computing.A typical JTWPA consists of thousands of Josephson junctions connected in series to form a transmission line and hundreds of shunt LC resonators periodically loaded along the line for phase *** the variation of these capacitors and inductors can be detrimental to their high-frequency characteristics,the fabrication of a JTWPA typically necessitates precise processing *** guide the fabrication process and further improve the design for manufacturability,it is necessary to understand how each electronic component affects the *** this paper,we use the harmonic balance method to conduct a comprehensive study on the impact of nonuniformity and fabrication yield of the electronic components on the performance of a *** results provide insightful and scientific guidance for device design and fabrication processes.

关键词： Josephson traveling wave parametric amplifier(JTWPA) harmonic balance method yields uniformity

A Design of 2-Stage Voltage Ramp-Up SRAM Physical Unclonable Function

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Chinese Journal of Electronics 2024年第2期33卷 371-379页

作者： Minte SONG Nan LIU Shuaiyang ZHOU Zhengguang WANG Zhanqiang RU Peng DING Wei HUANG Helun SONG School of Nano-tech and Nano-Bionics University of Science and Technology of China Suzhou Institute of Nano-tech and Nano-Bionics Chinese Academy of Sciences

Silicon physical unclonable function（PUF） implemented by static random access memory（SRAM）exists inherent demerit of unstable cells due to noise of environment and circuits, which significantly restricts its reproducibility. In this paper, a 16T SRAM cell with reset-delay circuit and a 2-stage voltage ramp up is fabricated and reported. Compared to conventional SRAM structure, each PUF cell adds a pair of pull-up PMOS（P-channel metal oxide semiconductor） and pull-down NMOS（N-channel metal oxide semiconductor） controlled by reset and delayedreset signals respectively, resulting in two positive feedback stages with different amplification coefficients when the voltage is ramped up. PUF array consists of 4064 cells, 322 dummy cells and a group of 8 series-connected inverters with an area of 304 μm × 650 μm to match the digital post-processing module. PUF test chip was fabricated in HHGrace 110 nm platform with total area 1140 × 1140 μm2. The average HDintra（intra-chip Hamming distance, also bit error rate, BER） and HDinter（inter-chip Hamming distance） values of the 50 PUF chips in SOP16 package measured at normal point（1.5 V/25 ℃） were 1.92% and 49.85%, respectively.

关键词： Semiconductor device measurement Circuits Bit error rate Metals Aging Physical unclonable function Reproducibility of results