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Rare Metals 2024年第4期43卷 1702-1712页

作者： Xuan Liu Zi-Xia Lin Yin-Biao Shi Xiao-Yan Wang Ming-Ye Ding Xiao-Fei Yang College of science Nanjing Forestry UniversityNanjing210037China testing Center Yangzhou UniversityYangzhou225009China

Regulating luminescent dynamics of lanthanide-based luminescent materials via external stimuli is of great significance in the fields of optical thermometry and high-level ***,it is still a huge challenge to realize multimodal emissions with tunable color outputs from a single activator in simple structures via smart dynamic control of photon transition ***,we present a mechanistic strategy to achieve multimodal luminescence of Er^(3+)activators with color-switchable outputs in a non-core-shell *** the control of excitation dynamics(λ_(ex)=980,808,1532,377 nm),the population among the intermediate en ergy levels of Er^(3+)and the interaction between Er^(3+)and Yb^(3+)could be precisely modulated through energy transfer and migration processes,leading to the generation of colortunable multimodal luminescence upon diverse excitation modes(non-steady-state,single-/dual-wavelength steady,thermal activation).Inspired by its special luminescent performance,the as-obtained material exhibits great potential in noncontact thermometry,multimodal anticounterfeiting,and high-capacity information encryption by performing a series of proof-of-concept *** findings might provide a conceptual model to modulate the luminescent dynamics in a simple-structured system for the generation of color-adjustable multimodal emissions,which is convenient for the development of advanced luminescent materials toward versatile cuttingedge applications.

关键词： Lanthanide ions Multimodal emission Upconversion Downshifting Anti-counterfeiting Luminescent thermometry

Mitigating set-stuck failure in 3D phase change memory: substituting square pulses with surge pulses

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science China(Information sciences) 2024年第5期67卷 295-301页

作者： Ninghua LI Wang CAI Jun XIANG Hao TONG Weiming CHENG Xiangshui MIAO School of Integrated Circuits Huazhong University of Science and Technology Hubei Yangtze Memory Laboratories Hubei Institute of Measurement and testing Technology

In the devices that integrate phase change memory(PCM) and ovonic threshold switching(OTS),the OTS threshold voltage often surpasses the RESET operation voltage of PCM. The conventional application of square pulses hinders the successful completion of the SET operation in these integrated devices. To address this challenge, a novel pulse called the surge pulse is introduced, which comprises a high amplitude pulse for OTS activation and a low amplitude pulse for PCM operation. By employing COMSOL simulation,the operational effectiveness of both square pulses and surge pulses is validated. Test results reveal that using a square pulse to operate the integrated device accelerates the occurrence of SET-stuck failure(SSF).In contrast, the surge pulse enables the integrated device to operate for at least 1000 cycles while preserving the essential cyclic characteristics. Additionally, an investigation into the overshoot component of the surge pulse is conducted, revealing that an increase in overshoot amplitude and pulse width also accelerates the emergence of SSF. By applying the theory of ion migration induced by the electric field, the root cause of SSF in integrated devices is explained, and the accuracy of the theory is validated through the application of a reverse pulse. In summary, this study elucidates the rationality of replacing the square pulse with a surge pulse, presenting a superior approach for operating PCM and OTS integrated devices.

关键词： surge pulse phase change memory (PCM) integration SET-stuck failure (SSF) square pulse

Heterobimetallic[NiCo]integration in a hydrogenase mimic for boosting light-driven hydrogen evolution in CaTiO_(3)

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Nano Research 2024年第8期17卷 6888-6894页

作者： Kang Li Juanji Hong Ningning Song Zhanjun Guo Minmin Liang experimental Center of Advanced Materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 10081China

Light-drive hydrogen production using titanium-based perovskite is one sustainable way to reduce current reliance on fossil fuels,but its wide applications are still limited by high electron−hole recombination and sluggish surface ***,the developments for low-cost and highly efficient co-catalysts remain *** by natural[NiFe]-hydrogenase active center structure,a hydrogenase-mimic,NiCo_(2)S_(4) nanozyme was synthesized,and subsequently decorated onto the CaTiO_(3) to catalyze the hydrogen evolution reaction(HER).Among the following test,CaTiO_(3)with a 15%loading of NiCo_(2)S_(4) nanozyme exhibited the highest HER rate of 307.76μmol·g^(–1)·h^(–1),which is 60 times higher than that of the CaTiO_(3) *** results reveal that NiCo_(2)S_(4) not only significantly increased the charge separation efficiency of the photogenerated carriers,but also substantively lowered the HER activation *** studies show that NiCo_(2)S_(4) readily splits H_(2)O by forming the Ni(OH)-Co intermediate and only Ni in the bimetallic center alters the oxidation state during the HER process in a manner analogous to the[NiFe]-*** contrast to the often-expensive synthetic catalysts that rely on rare elements such as ruthenium and platinum,this study shows a promising way to develop the nature-inspired cocatalysts to enhance the photocatalysts’HER performance.

关键词： hydrogen evolution reaction hydrogenase-mimic nanozyme photocatalyst water-splitting

Mathematical model and numerical investigation of the influence of spray drying parameters on granule sizes of mold powder

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Particuology 2024年第2期85卷 280-295页

作者： Fei Zhang Youyu Lu Shaoyan Zhu Funian Han Guanghua Wen Ping Tang Zibing Hou College of Materials science and Engineering Chongqing UniversityChongqing400044China Guizhou Academy of testing and Analysis Guizhou Academy of SciencesGuiyang550014China

In this work,the formation mechanism of the droplet-to-granule was investigated in detail based on mold powder manufacturing.A specific mathematical model of two-stage spray drying was established to describe droplet and granule motion,heat and mass transfer,and granule morphology during spray ***,the relationships between spray drying parameters(inlet temperature,atomization pres-sure,slurry mass flow rate)and the properties of the drying tower(temperature and velocity fields)and mold powder granules(temperature,evaporation rates,moisture content,and diameter)were simulated and calculated using ANSYS/Fluent *** ensure that the granule size of mold powder was controlled within the ideal range(0.2-0.6 mm)for producing granules with appropriate mechanical and metallurgical properties,the following optimum spray drying parameters were chosen based on the results of the numerical simulation:inlet temperatures,873 K;slurry atomization pressure,1.8 MPa;slurry mass flow rate,0.05 kg *** these parameters,the slurry mass flow rate has the most significant effect on granule size.

关键词： Mold powder slurry Spray drying parameters Mathematical model Numerical simulation Granule sizes

Vacancy healing for stable perovskite solar cells via bifunctional potassium tartrate

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Journal of Energy Chemistry 2024年第1期88卷 64-70,I0002页

作者： Jing Dou Yue Ma Xiuxiu Niu Wentao Zhou Xueyuan Wei Jie Dou Zhenhua Cui Qizhen Song Tinglu Song Huanping Zhou Cheng Zhu Yang Bai Qi Chen experimental centre for Advanced Materials School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory for Theory and Technology of Advanced Battery Materials Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationBIC-ESATSchool of Materials Science and EngineeringPeking UniversityBeijing 100871China

Perovskite solar cell has gained widespread attention as a promising technology for renewable ***, their commercial viability has been hampered by their long-term stability and potential Pb leakage. Herein, we demonstrate a bifunctional passivator of the potassium tartrate(PT) to address both challenges. PT minimizes the Pb leakage in perovskites and also heals cationic vacancy defects, resulting in improved device performance and stability. Benefiting from PT modification, the power conversion efficiency(PCE) is improved to 23.26% and the Pb leakage in unencapsulated films is significantly reduced to 9.79 ppm. Furthermore, the corresponding device exhibits no significant decay in PCE after tracking at the maximum power point(MPP) for 2000 h under illumination(LED source, 100 mW cm^(-2)).

关键词： Perovskite Potassium tartrate Lead leakage Long-term stability

Effect of Central Multiphase Microstructure of Thick Plates on Work Hardening and Crack Propagation

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 325-338页

作者： Lei Hu Liqin Zhang Feng Hu Kuan Zheng Guohong Zhang Collaborative Innovation Center for Advanced Steels Wuhan University of Science and TechnologyWuhan430081China Department of Applied Physics Wuhan University of Science and TechnologyWuhan430081China Analysis and testing Center Wuhan University of Science and TechnologyWuhan430081China

The effect of multiphase microstructure in the center segregation zones(CSZ)of high-strength steel thick plates on work hardening characteristics and crack initiation/propagation were *** was correlated with deformation damage behavior by using Taylor factor(TF)gradients,kernel average misorientation(KAM),and geometric necessary dislocation(GND)*** results show that the segregation leads to a mixed structure of ferrite(soft phase)and martensite/bainite(hard phase)in the center of the thick *** to the 1/4 thickness(1/4 T)region,grain refinement occurred in the CSZ,with KAM values increasing from 0.24 to 0.49 and a decrease in the proportion of high-angle grain boundaries(>15°)from 77.4 to 51.8%.In the process of deformation,due to the influence of grain refinement and adjacent martensite/bainite,ferrite grains were divided into structural units with different TF *** higher KAM value and GND density at the interface between soft/hard phases resulted in severe work *** addition,the presence of micron-sized inclusions in the CSZ caused local strain concentration and non-continuous deformation of the matrix,which induced crack *** fracture surface showed a mixed mode of brittle cleavage fracture and ductile fracture.

关键词： Thick plate Center segregation zone Multiphase microstructure Taylor factor Crack propagation

Enhancing ionic conductivity of garnet-type Nb-doped Li_(7)La_(3)Zr_(2)O_(12)by cerium doping

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Journal of Rare Earths 2024年第9期42卷 1740-1746,I0004页

作者： Daming Liu Yuan Hou Chaoke Bulin Ruichao Zhao Bangwen Zhang Analytical and testing Center Inner Mongolia University of Science and TechnologyBaotou014010China School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou014010China School of Metallurgy and Materials Engineering Chongqing University of Science and TechnologyChongqing401331China

We investigated the effect of additional doping with Ce on the ionic conductivity of the Nb-doped Li_(7)La_(3)Zr_(2)O_(12)(LLZO)garnet ceramics using a combination of experimental and modeling *** results indicate that Ce doping can alter lattice parameters of the LLZNO,leading to the enhanced lithium ionic *** Ce,Nb co-doped LLZO(LLZNCO)structure with composition Li_(6.5)La_(3)Zr_(1.5-x)Nb_(0.5)Ce_(x)O_(12)(x=0.125)exhibits a lower activation energy(E_(a)=0.39 eV)than Li_(6.5)La_(3)Zr_(1.5)Nb_(0.5)O_(12)(LLZNO)(E_(a)=0.41 eV).Furthermore,Ce doping leads to an increase in Li~+conductivity from 6.4×10^(-4)to 7×10^(-4)S/cm at room *** addition,we discuss the diffusivity and conductivity of our samples using ab initio molecular dynamics simulations and propose possible mechanisms to explain the enhanced Li-ion conductivity caused by co-doping with Ce and *** results demonstrate that the LLZNCO ceramics are promising candidates for potential solid-state electrolytes for Li-ion batteries.

关键词： Rare earths Solid state electrolyte Ionic conductivity Doping

Quantitative analysis on resistant forces at oil-surfactant-rock interfaces with dynamic wettability characterization

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Energy Geoscience 2024年第3期5卷 305-312页

作者： Qiaoyu Ge Tao Ma Guanli Xu Zengmin Lun science and Technology experimental Research Center Petroleum Exploration and Production Research InstituteSINOPECBeijingChina

Adhesion of oil at rock surface plays an important role in the liberation of oil from micro-/nano-pores,especially for heavy oil that has extremely high *** molecular dynamics simulation is widely used to study the interfacial interaction for some specific oil-water-rock systems,experimental measurements provide more realistic and reliable *** this work,we propose a dynamic wettability characterization method to indirectly measure resistant forces at oil-surfactant-rock interfaces,including frictional force,wettability hysteresis force,and viscous force,which are parallel with the oil-solid *** adhesive force,which is normal to the oil-solid interface is calculated through measurement of work of *** results show that work of adhesion instead of contact angle can better describe the adhesion of oil at solid *** effect of surfactant concentration on work of adhesion is different for water-wet and oil-wet ***,average viscous forces are calculated through force analysis on oil drops moving along solid surface in different surfactant *** is found that viscous force has a magnitude comparable to the frictional force during the movement,while the wettability hysteresis force is *** the other hand,the adhesive force calculated from the work of adhesion is also comparable to the viscous ***,both the resistant forces parallel with and normal to the oil-solid interface should be minimized for the liberation of oil from rock *** work proposes a simple method to evaluate the wetting capability of different surfactants and measure the adhesive force between heavy oil and rock surfaces indirectly,which provides insight into the adhesion of heavy oil at rock surface and would be valuable for the development of surfactant-based oil recovery methods.

关键词： Work of adhesion Wettability characterization Adhesive force Viscous force Surfactant

Fracture mechanism of inclusions in thick plate center under tensile loading

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Journal of Iron and Steel Research International 2024年第5期31卷 1196-1209页

作者： Lei Hu Li-qin Zhang Feng Hu Guo-hong Zhang Kuan Zheng Collaborative Innovation Center for Advanced Steels Wuhan University of Science and TechnologyWuhan430081HubeiChina Department of Applied Physics Wuhan University of Science and TechnologyWuhan430081HubeiChina Analysis and testing Center Wuhan University of Science and TechnologyWuhan430081HubeiChina

Segregation of solute atoms in the center of thick plates of the tempered steel can cause an inhomogeneous structural transformation and generate micron-sized inclusions,which leads to lamellar tearing of thick plate and decreases the plasticity and *** formation and fragmentation mechanisms of micron-sized inclusions,like MnS and(Nb,Ti)C,in the center of thick plates were investigated by using thermodynamic calculations,finite element simulations,and electron backscatter diffraction characterization *** results show that micron-sized inclusions nucleate and grow in the liquid phase,and under tensile loading,they exhibit three fragmentation *** local stress during the fragmentation of inclusions is lower than the critical fracture stress of adjacent grains,and phase boundaries can effectively impede crack propagation into the *** existence of a low proportion of high-angle grain boundaries(58.1%)and high Kernel average misorientation value(0.534°)in the segregation band promotes inclusions fragmentation and crack *** difference in crack initiation and propagation direction caused by the morphology of inclusions and physical properties,as well as different matrix arrest abilities,is the main reasons for the diversity of inclusion fragmentation.

关键词： Thick plate Inclusion Finite element simulation Critical fracture stress Fracture mechanism

Tribological Behaviors of Electroless Nickel-Boron Coating on Titanium Alloy Surface

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 309-320页

作者： Yao Jia Jianping Lai Jiaxin Yu Huimin Qi Yafeng Zhang Hongtu He Key Laboratory of testing Technology for Manufacturing Process in Ministry of Education State Key Laboratory of Environment-Friendly Energy MaterialsSouthwest University of Science and TechnologyMianyang 621010China

Titanium alloys are excellent structural materials in engineering fields,but their poor tribological properties limit their further *** plating is an effective method to enhance the tribological performance of alloys,but it is difficult to efficiently apply to titanium alloys,due to titanium alloy’s strong chemical *** this work,the electroless Nickel-Boron(Ni-B)coating was successfully deposited on the surface of titanium alloy(Ti-6AL-4V)via a new pre-treatment ***,linearly reciprocating sliding wear tests were performed to evaluate the tribological behaviors of titanium alloy and its electroless Ni-B *** was found that the Ni-B coatings can decrease the wear rate of the titanium alloy from 19.89×10^(−3)mm^(3)to 0.41×10^(−3)mm^(3),which attributes to the much higher hardness of Ni-B *** heat treatment,the hardness of Ni-B coating further increases corresponding to coating crystallization and hard phase ***,heat treatment does not improve the tribological performance of Ni-B coating,due to the fact that higher brittleness and more severe oxidative wear exacerbate the damage of heat-treated ***,the Ni-B coatings heat-treated both in air and nitrogen almost present the same tribological *** finding of this work on electroless coating would further extend the practical applications of titanium alloys in the engineering fields.

关键词： Electroless coating Titanium alloy Tribology Wear Heat treatment Nanoindentation