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One-step production of high-strength titanium alloy by sintering titanium hydride powder from upgraded titania slag

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Transactions of Nonferrous Metals Society of China 2022年第11期32卷 3801-3809页

作者： Zhao-wang dong Yang XIA Xue-yi GUO Qing-hua TIAN Han-ning liu pei-dong liu Yu-bing CHEN School of Metallurgy and Environment Central South UniversityChangsha 410083China Research Institute of Resource Recycling Central South UniversityChangsha 410083China

A direct production method of high-strength titanium alloy from upgraded titania slag(UGS)was ***,UGS was reduced into alloy powder with 1.3 wt.%oxygen using magnesium ***,the alloy powder was compacted at 600 MPa to produce a ***,the pellet was sintered to produce titanium *** reduced powder was characterized,and the effect arising from the sintering temperature on the sintered density,compressive strength,microstructure,and hardness of the alloys was *** results showed that the density tended to increase with the temperature increasing from 900 to 1200℃,whereas the porosity decreased.A significant sintering densification was achieved at the temperature above 1100℃(98.65%at 1100℃ and 99.41%at 1200℃).At 1100℃,the hardness and compressive strength reached the maximal values of the alloy,HV 655.7 and 1563 MPa,respectively.

关键词： upgraded titania slag reduction titanium alloy sintering

Design of efficient thermoelectric generators

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Science China Materials 2024年第1期67卷 377-378页

作者： Min liu Yanzhong pei Interdisciplinary Materials Research Center School of Materials Science and EngineeringTongji UniversityShanghai 201804China

Thermoelectricity,which enables direct conversion between heat and electricity,undergoes impressive developments in recent decades,and is particularly promising for recovering low-grade heat of<600 K[1,2].Currently,only Bi2Te3-based thermoelectric devices are commercialized[3].However,the scarcity of tellurium(Te)(Fig.1a)is the main *** leads to numerous recent efforts on the development of efficient nonBi2Te3 thermoelectrics as potential alternatives,and successful examples(Fig.1b)include Mg3Sb2-alloys[2,3]and MgAgSb[1,2].

关键词： enable efficient electricity

High-performance sodium storage for cobalt phosphide composite array electrodes

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Rare Metals 2024年第8期43卷 3724-3734页

作者： Man Zhang Xiao-Xu liu Tian-Yi Ji Yang Li Da-Wei Sheng Shao-dong Li pei-pei Ren Ze-Xiang Shen School of Material Science and Engineering Shaanxi University of Science and TechnologyXi'an 710021China School of Physical and Mathematical Sciences Nanyang Technological UniversitySingapore 637371Singapore

Transition metal phosphides hold great potential as sodium-ion batteries anode materials owing to their high theoretical capacity and modest ***,volume changes and low intrinsic conductivity seriously largely hinder the further development of metal phosphide *** design of phosphide anode materials with reasonable structure is conducive to solving the problems of volume expansion and slow reaction kinetics during the *** this work,a composite material integrating zeolite imidazolate backbone(ZIF) and carbon materials was synthesized by the original growth ***,by the oxidation-phosphating process,CoP nanoarray composites riveted to carbon fiber(CoP@CF) were *** the CoP@CF,CoP nanoparticles are uniformly distributed on ZIF-derived carbon,reducing agglomeration and volume change during *** also provides a highly conductive network for the active material,improving the electrode ***,when evaluated as an anode for sodium-ion batteries,CoP@CF electrode displays enhanced reversible capacity(262 mAh·g^(-1) at 0.1 A·g^(-1)after 100 cycles),which is much better than that of pure CF electrode(57 mAh·g^(-1) at 0.1 A·g^(-1) after 100 cycles)prepared without the addition of *** rate performance of CoP@CF electrode is also superior to that of pure CF electrode at various current densities from 0.05 to1 A·g^(-1).The sodium storage behavior of CoP@CF was revealed by ex-situ X-ray photoelectron spectroscopy,X-ray diffraction,and synchrotron radiation absorption *** method provides a reference for the design and synthesis of anode materials in sodium-ion batteries.

关键词： Cobalt phosphide Array structure Freestanding anodes Sodium-ion batteries

Early fire detection technology based on improved transformers in aircraft cargo compartments

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Journal of Safety Science and Resilience 2024年第2期5卷 194-203页

作者： Hongzhou Ai dong Han Xinzhi Wang Quanyi liu Yue Wang Mengyue Li pei Zhu College of Civil Aviation Safety Engineering Civil Aviation Flight University of ChinaGuanghan618307China CivilAircraf Fire Science and Safety Enginring Key Laboratory of Sichuan CivilAviation Flight University of ChinaGuanghan 618307China School of Computer Engineering and Science Shanghai UniversityShanghai 200444China Key Laboratory of Civil Aviation Emergency Science&Technology Nanjing University of Aeronautics and AstronauticsNanjing 210000China

The implementation of early and accurate detection of aircraft cargo compartment fire is of great significance to ensure flight *** current airborne fire detection technology mostly relies on single-parameter smoke detection using infrared *** often results in a high false alarm rate in complex air transportation *** traditional deep learning model struggles to effectively address the issue of long-term dependency in multivariate fire *** paper proposes a multi-technology collaborative fire detection method based on an improved transformers ***-wavelength optical sensors,flue gas analyzers,and other equipment are used to carry out multi-technology collaborative detection methods and characterize various feature dimensions of fire to improve detection *** improved Transformer model which integrates the self-attention mechanism and position encoding mechanism is applied to the problem of long-time series modeling of fire information from a global perspective,which effectively solves the problem of gradient disappearance and gradient explosion in traditional RNN(recurrent neural network)and CNN(convolutional neural network).Two different multi-head self-attention mechanisms are used to classify and model multivariate fire information,respectively,which solves the problem of confusing time series modeling and classification modeling in dealing with multivariate classification tasks by a single attention ***,the output results of the two models are fused through the gate *** research results show that,compared with the traditional single-feature detection technology,the multi-technology collaborative fire detection method can better capture fire *** with the traditional deep learning model,the multivariate fire pre-diction model constructed by the improved Transformer can better detect fires,and the accuracy rate is 0.995.

关键词： Deep learning Aircraft cargo compartment Attentionmechanism Firedetection Multi-sourcedata fusion

L^p and L~∞ Norm Estimates of the Cost of the Controllability for Heat Equations

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Acta Mathematica Sinica,English Series 2009年第8期25卷 1305-1324页

作者： pei dong LEI Xu liu Hang GAO School of Mathematics & Statistics Northeast Normal University Changchun 130024 P. R. China

This paper is concerned with the bound of the cost of approximate controllability and null controllability of heat equations, i.e., the minimal Lp norm and L∞ norm of a control needed to control the system approximately or a control needed to steer the state of the system to zero. The methods we use combine observability inequalities, energy estimates for heat equations and the dual theory.

关键词： approximate controllability null controllability cost of the controllability observability inequality

Divergent defluorocarboxylation of α-CF_(3) alkenes with formate via photocatalyzed selective mono-or triple C-F bond cleavage

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Science China Chemistry 2024年第1期67卷 368-373页

作者： Xing-Yu Wang pei Xu Wen-Wen liu Hao-Qiang Jiang Song-Lei Zhu dong Guo Xu Zhu Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy School of PharmacyXuzhou Medical UniversityXuzhou 22100China

Unprecedented divergent synthesis of gem-difluorovinylacetic acid and glutaric acid derivatives fromα-CF_(3)alkenes with formate as the carbonyl source was *** reaction can undergo selective mono-or triple C-F bond cleavage by simply switching the photocatalyst and hydrogen atom transfer(HAT)catalyst under visible-light-induced conditions at room *** acts as both the C1 source and the reductant through the generation of CO_(2)^(·-)species,which underwent Giese radical addition to electron-deficient alkenes to trigger the consecutive C-F bond cleavage and carboxylation process.

关键词： C-F bond activation defluorocarboxylation carbon dioxide radical anion visible light

Modeling urban scale human mobility through big data analysis and machinelearning

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Building Simulation 2024年第1期17卷 3-21页

作者： Yapan liu Bing dong Department of Mechanical&Aerospace Engineering Syracuse University263 Link HallSyracuseNY 13244USA

In the United States,the buildings sector consumes about 76%of electricity use and 40% of all primary energy use and associated greenhouse gas *** behavior has drawn increasing research interests due to its impacts on the building energy ***,occupant behavior study at urban scale remains a challenge,and very limited studies have been *** an effort to couple big data analysis with human mobility modeling,this study has explored urban scale human mobility utilizing three months Global Positioning System(GPS)data of 93,o00 users at Phoenix Metropolitan *** research extracted stay points from raw data,and identified users'home,work,and other locations by Density-Based Spatial Clustering ***,daily mobility patterns were constructed using different types of *** propose a novel approach to predict urban scale daily human mobility patterns with 12-hour prediction horizon,using Long Short-Term Memory(LSTM)neural network *** shows the developed models achieved around 85%average accuracy and about 86%mean *** developed models can be further applied to analyze urban scale occupant behavior,building energy demand and flexibility,and contributed to urban planning.

关键词： urban human mobility big data analysis urban scale occupant behavior recurrent neural networks

Covalency competition induced selective bond breakage and surface reconstruction in manganese cobaltite towards enhanced electrochemical charge storage

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Green Energy & Environment 2024年第5期9卷 909-918页

作者： Peng Gao pei Tang Ying Mo peitao Xiao Wang Zhou Shi Chen Hongliang dong Ziwei Li Chaohe Xu Jilei liu College of Materials Science and Engineering Hunan Joint International Laboratory of Advanced Materials and Technology for Clean EnergyHunan Province Key Laboratory for Advanced Carbon Materials and Applied TechnologyHunan UniversityChangshaHunan410082China Department of Materials Science and Engineering National University of Defense TechnologyChangshaHunan410073China Joint Key Laboratory of the Ministry of Education Institute of Applied Physics and Materials EngineeringUniversity of MacaoAvenida da UniversidadeTaipaMacao999078China Center for High Pressure Science and Technology Advanced Research PudongShanghai201203China College of Aerospace Engineering Chongqing UniversityChongqing400044China

Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage *** previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into d-MnO_(2) nanosheets irreversibly,thus results in a change of the reaction mechanism with Kþion ***,the low capacity has greatly limited its practical ***,we found that the tetrahedrally-coordinated Co_(2) þions were leached when MnCo_(2)_(4) was equilibrated in 1 mol L^(-1) HCl solution,leading to the formation of layered CoOOH on MnCo_(2)_(4) surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free Co_(6) *** as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced speciﬁc capacity as well as facilitated charge transfer and ion *** general,our work not only offers a feasible approach to deliberate modiﬁcation of MnCo_(2)_(4)'s surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.

关键词： Manganese cobaltite Tetrahedrally-coordinated Co^(2+)leaching Selective bond breakage Surface reconstruction Charge storage mechanisms

Synthesis, Characterization and Properties of Poly(aryl amides) Containing Methoxy Substituted Phthalazinone Moiety

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Chinese Chemical Letters 2005年第10期16卷 1324-1326页

作者： pei WANG Jian dong liu Xi Gao JIAN Department of Polymer Science ＆ Materials Dalian University of Technology Dalian 116012

A novel aromatic diamine, 1, 2-dihydro-2-（4-aminophenyl）-4-[3-methoxy-4-（4-aminophenoxy）]-2, 3-phthalazin-l-one （OO-DA） containing aza heterocyclic structure was synthesized from the bisphenol-like monomer in two steps and used for preparing new aromatic polyamides with high inherent viscosity of 0.89-1.03 dL.g^-1. The structures of diamine and polymers obtained were confirmed by MS, PT-IR, WAXD and ^1H-NMR. The synthesized polymers exhibited high glass transition temperature in the range of 281-307℃ and good solubility in polar solvents.

关键词： Poly(ether amides) phthalazinone solubility.