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Single-source precursor derived high-entropy metal–carbide nanowires:Microstructure and growth evolution

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Journal of Advanced Ceramics 2023年第11期12卷 2041-2052页

作者： Junhao Zhao Yulei Zhang Hui Chen Yanqin Fu Qing Miao jiachen Meng jiachen Li Shaanxi Key Laboratory of Fiber Reinforced light Composite Materials Northwestern Polytechnical UniversityXi’an 710072China Henan Key Laboratory of High Performance Carbon Fiber Reinforced Composites Institute of Carbon Matrix CompositesHenan Academy of SciencesZhengzhou 450046China

In recent years,high-entropy metal carbides(HECs)have attracted significant attention due to their exceptional physical and chemical properties.The combination of excellent performance exhibited by bulk HEC ceramics and distinctive geometric characteristics has paved the way for the emergence of one-dimensional(1D)HECs as novel materials with unique development potential.Herein,we successfully fabricated novel(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C nanowires derived via Fe-assisted single-sourced precursor pyrolysis.Prior to the synthesis of the nanowires,the composition and microstructure of(Ti,Zr,Hf,Nb,Ta)-containing precursor(PHECs)were analyzed,and divinylbenzene(DVB)was used to accelerate the conversion process of the precursor and contribute to the formation of HECs,which also provided a partial carbon source for the nanowire growth.Additionally,multi-branched,single-branched,and single-branched bending nanowires were synthesized by adjusting the ratio of PHECs to DVB.The obtained single-branched(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C nanowires possessed smooth surfaces with an average diameter of 130–150 nm and a length of several tens of micrometers,which were a single-crystal structure and typically grew along the[11¯1]direction.Also,the growth of the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C nanowires was in agreement with top-type vapor–liquid–solid mechanism.This work not only successfully achieved the fabrication of HEC nanowires by a catalyst-assisted polymer pyrolysis,but also provided a comprehensive analysis of the factors affecting their yield and morphology,highlighting the potential application of these attractive nano-materials.

关键词： (Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C nanowires high-entropy metal carbides(HECs) (Ti,Zr,Hf,Nb,Ta)-containing precursors vapor–liquid–solid(VLS)mechanism

Understanding self-accelerated water diffusion within poly-lactic acid via molecular dynamics simulation

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Chinese Journal of Chemical Engineering 2019年第4期27卷 759-764页

作者： Xiaohui Wang jiachen Li li Zhang School of Economics and Management Tianjin University of Technology and Education Tianjin 300222 China Department of Chemistry Zhejiang Sci-Tech University XiaSha Higher Education Zone Hangzhou 310018 China

Poly-lactic acid(PLA) is widely used as a controlled drug release material and the diffusion property of water within the polymer matrix is closely related to the drug release profile. This paper studies the water diffusion in PLA by molecular dynamic simulations. Free volume analysis indicates that water molecules are expected to fill in the free volumes of the polymer matrix forming water clusters at low water content. Along with the increase of the water concentration, the polymer starts to swell and the density of the system starts to drop.Due to the high mobility of water within water cluster, the calculated diffusion coefficient dramatically increases along with the incensement of water content. Thus, we conclude that the diffusion of water is a self-accelerate process, with higher mobility of water in the case where more water exists.

关键词： Water diffusion coefficient Controlled release Molecular dynamic simulation

Multiscale microstructural consideration of enhanced shear strength in TiAl intermetallic/K4169 alloy composite joints prepared by vacuum brazing with(Ti,Zr)-Ni-based amorphous filler metal

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Journal of Materials Science & Technology 2024年第5期172卷 51-70页

作者： liangliang Zhang Honggang Dong Peng li Baosheng Wu Yueting Ma libing Huang Chao li jiachen Li School of Materials Science and Engineering Dalian University of TechnologyDalian 116024China

TiAl intermetallic could be used to replace Ni-based alloy in assemblies to generate excellent specific strength.A(Ti,Zr)-Ni-based amorphous filler metal Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)(at.%)was designed using a cluster-plus-glue-atom model to successfully vacuum braze K4169 and TiAl bimetallic assemblies.At various brazing temperatures and holding time,the quantitative relationships between lattice distortion,grain boundary,dislocation density,and hardness,elastic modulus,shear strength of the joints were investigated.Meanwhile,the fracture mechanism of the joints was revealed.The brazed seam mainly consisted of solid diffusion reaction layers(ZonesⅠandⅢ)and filler metal residue zone(ZoneⅡ).When the brazing temperature increased to 1030℃,grain refinement occurred in the brazed seam.ZoneⅠwas primarily composed of(Ni)ss[0-11]+TiNi[011]/(Cr,Fe,Ni)ss[0-11]/(Ti,Zr)Ni[0-1-1]+(Cr,Fe,Ni)ss[0-11].The(Ti,Zr)(Ni,Cu)[001]and(Ti,Zr)(Ni,Cu)[101]intermetallic compound-based solid solutions were formed in ZoneⅡ.And the lattice distortion of(Ti,Zr)(Ni,Cu)[101]and(Ti,Zr)(Ni,Cu)[001]was 32.05%and 14.82%,respectively.As a result,the proportion of low angle grain boundaries(LAGBs)and deformed grains in ZoneⅡrose to 38.6%and 38.7%.In ZonesⅠandⅢ,the proportion of LAGBs reduced to 8%and 3.4%,respectively.As the holding time increased,the long-range diffusion of Al in ZoneⅡcaused the(Ti,Zr)(Ni,Cu)[001]with cubic structure to transform into(Ti,Zr)(Ni,Cu,Al)[00-1]with hexagonal crystal system structure,where the lattice distortion was 4.42%and 10.49%for a and c.At 1030℃/10 min,the average geometrically nec-essary dislocation densities(GNDs)in ZonesⅠ,ⅡandⅢwere 9.87×10^(14)m^(-2),8.55×10^(14)m^(-2)and 11.4×10^(14)m^(-2),respectively.Therefore,the shear strength of joints reached 322 MPa due to the lattice distortion,dislocation strengthening and fine grain strengthening.Meanwhile,the plastic and brittle hard phases were generated in ZoneⅡand displayed a mechanical interlocking structure that contributed to the performance of the joint.Bo

关键词： K4169/Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)/TiAl composite joints Intermetallic compound-based solid solution Lattice distortion Elastic modulus

Influence of ambient temperature on the CO_(2)emitted of light-duty vehicle

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Journal of Environmental Sciences 2024年第6期140卷 59-68页

作者： Dan Tan Yachao Wang Jianwei Tan jiachen Li Changyu Wang Yunshan Ge School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China

Because of global warming,people have paid more attention to greenhouse gas emitted by vehicles.To quantify the impact of temperature on vehicle CO_(2)emissions,this study was conducted using the world light vehicle test cycle on two light-duty E10 gasoline vehicles a ambient temperatures of-10,0,23,and 40℃,and found that CO_(2)emission factors of Vehicle1 in the low-speed phase were 22.07%and 20.22%higher than those of Vehicle 2 at cold star and hot start under-10℃.The reason was vehicle 1 had a larger displacement and more friction pairs than vehicle 2.There was the highest CO_(2)emission at the low-speed phase due to low average speed,frequent acceleration,and deceleration.The CO_(2)temperature factor and the ambient temperature had a strong linear correlation(R2=0.99).According to CO_(2)temperature factors and their relationships,CO_(2)emission factors of other ambien temperatures could be calculated when the CO_(2)emission factor of 23℃was obtained,and the method also could be used to obtain the CO_(2)temperature factors of different vehicles.To separate the effect of load setting and temperature variation on CO_(2)emission quantitatively a method was proposed.And results showed that the load setting was dominant for the CO_(2)emission variation.Compared with 23℃,the CO_(2)emission for vehicle 1 caused by load setting variation were 62.83 and 47.42 g/km,respectively at-10 and 0℃,while those fo vehicle 2 were 45.01 and 35.63 g/km,respectively.

关键词： CO_(2)emission Ambient temperature E10 gasoline light-duty vehicle WLTC

The effect of NiO-Ni_(3)N interfaces in in-situ formed heterostructure ultrafine nanoparticles on enhanced polysulfide regulation in lithium-sulfur batteries

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Journal of Energy Chemistry 2022年第5期31卷 762-770页

作者： Jun Pu Zhenghua Wang Pan Xue Kaiping Zhu jiachen Li Yagang Yao Key Laboratory of Functional Molecular Solids Ministry of EducationAnhui Provincial Engineering Laboratory for New-Energy Vehicle Battery Energy-Storage MaterialsCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002AnhuiChina National Laboratory of Solid State Microstructures College of Engineering and Applied SciencesJiangsu Key Laboratory of Artificial Functional MaterialsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093JiangsuChina School of Chemical Engineering Northwest UniversityXi’an 710069ShaanxiChina Division of Nanomaterials and Jiangxi Key Lab of Carbonene Materials Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesNanchang 330200JiangxiChina

Inhibiting the “shuttle effect” of soluble polysulfides and improving reaction kinetics are the key factors necessary for further exploration of high-performance li-S batteries. Herein, an effective interface engineering strategy is reported, wherein nitriding of an Ni-based precursor is controlled to enhance li-S cell regulation. The resulting in-situ formed NiO-Ni_(3)N heterostructure interface not only has a stronger polysulfide adsorption effect than that of monomeric NiO or Ni_(3)N but also has a faster li ion diffusion ability than a simple physical mixture. More importantly, this approach couples the respective advantages of NiO and Ni_(3)N to reduce polarization and facilitate electron transfer during polysulfide reactions and synergistically catalyze polysulfide conversion. In addition, ultrafine nanoparticles are thought to effectively improve the use of additive materials. In summary, li-S batteries based on this NiO-Ni_(3)N heterostructure have the features of long cycle stability, rapid charging-discharging, and good performance under high sulfur loading.

关键词： NiO-Ni_(3)N heterostructure Interface effect Ultrafine nanoparticles li-S batteries Polysulfides

Efficient hydrogenation of ethylene carbonate derived from CO_(2) to synthesize methanol and ethylene glycol over core-shell Cu@GO catalyst

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Green Chemical Engineering 2022年第3期3卷 228-239页

作者： Chanjuan Zhang liguo Wang Zhuo Han Peng He Yan Cao jiachen Li Huiquan li CAS Key Laboratory of Green Process and Engineering National Engineering Research Center of Green Recycling for Strategic Metal ResourcesInstitute of Process EngineeringChinese Academy of SciencesBeijing100190China Sino-Danish College University of Chinese Academy of SciencesBeijing100049China Sino-Danish Center for Education and Research University of Chinese Academy of SciencesBeijing100049China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China Dalian National Laboratory for Clean Energy Dalian116023China

The synthesis of sustainable methanol and ethylene glycol(EG)via hydrogenation of ethylene carbonate(EC)has caught researchers’growing interests on account of the indirect chemical utilization of CO_(2).Core-shell Cu@GO catalysts with random nanoporous network of graphite oxide(GO)were synthesized via a simple method of ul-trasonic precipitation.Cu@GO catalysts were analyzed systematically by N_(2) physisorption,TGA measurement,XRD,FT-IR,Raman,TEM,SEM,and XPS(XAES).In particular,the mentioned method was confirmed to be effective to fabricate the high dispersity core-shell Cu@GO catalysts through promoting the specific surface area.The as-prepared Cu@GO catalyst was then successfully applied in the hydrogenation of CO_(2)-derived EC to pro-duce methanol and EG.A high TOF of 1526 mg EC g cat^(-1) h^(-1) could be attained in EC hydrogenation at the reaction temperature of 493K.Accordingly,the correlation of catalytic structure and performance disclosed that the synergistic effect between Cu^(+) and Cu^(0) was responsible for achieving high activity of the catalyst.In addition,the reusability of Cu@GO catalyst suggested that graphite oxide shell structure could decrease the aggregation of Cu particles,thus enhance the stability of Cu-based catalysts.DFT calculation results suggested that the involvement of carbon film on Cu was favorable for the stabilization of the active sites.This study is helpful for developing new and stable catalytic system for indirect chemical utilization of CO_(2) to synthesize commodity methanol and EG.

关键词： Ethylene carbonate Selective hydrogenation Methanol Ethylene glycol Cu-based catalyst

Stability and Thermal Property Optimization of Propylene Glycol-Based MWCNT Nanofluids

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Fluid Dynamics & Materials Processing 2023年第9期19卷 2399-2416页

作者： Xi Wang Shan Qing Zhumei Luo Yiqin liu Zichang Shi jiachen Li Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunming650093China Faculty of Media and Information Engineering Yunnan Open UniversityKunming650093China

Propylene glycol-based MWCNT(multi-walled carbon nanotubes)nanoﬂuids were prepared in the framework of a two-step method and by using a suitable PVP(polyvinyl pyrrolidone)dispersant.The BBD(Box-Behnken design)model was exploited to analyze 17 sets of experiments and examine the sensitivity of the absorbance to three parameters,namely the concentration of MWCNT,the SN ratio(mass ratio of carbon nanotubes to sur-factants)and the sonication time.The results have revealed that,while the SN ratio and concentration of MWCNT have a strong effect on the absorbance,the inﬂuence of the sonication time is less important.The sta-tistical method of analysis of variance(ANOVA)was further used to determine the F-and p-values of the model.Five experiments were run to validate this approach.Since sample 2 was found to display the greatest absorbance,it was selected for stability monitoring as well as thermal conductivity and viscosity measurements.This sample has been found to be stable;the viscosity decreased with increasing temperature;the addition of MWCNT nano-particles was more effective in improving the thermal conductivity of propylene glycol than other methods in the literature.Moreover,the MWCNT nanoﬂuid based on propylene glycol exhibited higher thermal conductivity at low temperatures.

关键词： Propylene glycol thermal conductivity response surface methodology stability viscosity

Vacuum brazing TiAl intermetallic to K4169 alloy using amorphous filler metals Ti_(56.25–x)Zr_(x)Ni_(25)Cu1_(8.75)

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Journal of Materials Science & Technology 2023年第23期154卷 217-231页

作者： liangliang Zhang Honggang Dong Peng li Shuai li Baosheng Wu Yueting Ma libing Huang Chao li jiachen Li Yuesen Yang School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China School of Mechanical Engineering North China University of Water Resources and Electric Power Zhengzhou 450045 China

A series of Ti_(56.25-x)Zr_(x)Ni_(25)Cu1_(8.75)(x=0–25,at.%) filler metals were designed based on a cluster-plus-glue-atom model to vacuum braze TiAl intermetallic to K4169 alloy. The impact of Zr content on the interfacial microstructure and shear strength of joints was examined. And the relationship between the interfacial lattice structure and the fracture behavior of the joint was investigated. The findings reveal a sectionalized characteristic with three reaction zones (Zone I, Zone II and Zone III) in the microstructure of the TiAl intermetallic to K4169 alloy joint. As the Zr content in filler metals increased, the diffusion of Ti transitioned from long-distance to short-distance in Zone I, changing the initial composition from TiNi_(3) /TiNi/NiNb/(Cr, Fe, Ni)SS to NiCrFe/(Cr, Fe, Ni)SS /TiNi. In Zone II, the initial composition altered from TiNi_(3) /TiNi to TiNi/Ti_(2) Ni/TiNi_(3) /TiCu/TiNi. The interface between Zones II and III altered from a non-coherent and semi-coherent interface of TiNi/TiAl/Ti_(3) Al with significant residual stress to a semi-coherent interface of TiNi/TiNi_(3) /TiAl_(2) /Ti_(3) Al with a gradient distribution. The shear strength of the joint initially decreased and then increased. When the Zr content of filler metal was 25 at.%, the shear strength of the joint reached 288 MPa. The crack initiation position changed from non-coherent TiNi/TiAl interface with high angle grain boundaries (HAGBs) and lattice mismatch of 65.86 at.% to a semi-coherent Ti3 Al/TiAl2 interface with a lattice mismatch of 20.07 at.% when the Zr content increased. The brittle fracture was present on the fracture surfaces of all brazed joints.

关键词： Vacuum brazing TiAl intermetallic to K4169 alloy brazed joint Ti-Ni based amorphous filler metal EBSD Lattice mismatch

A stretchable flexible electronic platform for mechanical and electrical collaborative design

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Science China(Information Sciences) 2018年第6期61卷 95-109页

作者： Ziming DONG Baoxing DUAN jiachen Li Yintang YANG School of Microelectronic Xidian University

With the extensive application of stretchable flexible electronic circuits to wearable equipment and biomedicine, research on the electrical properties of such circuits has become a hot topic. In this paper, a flexible electronic design platform is established for the first time, realizing co-simulation of the mechanical and electronic aspects. The main functions of this platform include the design of stretchable interconnects, flexible devices, stretchable flexible electronic circuits, and stretchable flexible circuit-layout wiring. The following conclusions can be obtained:(1) With increased applied strain, the inductance of a stretchable interconnect will increase, while the delay and crosstalk will become non-negligible.(2) Although the performance of flexible passive devices does not change after transfer printing, the gate capacitor of the flexible MOS at the cut-off area does decrease.(3) Taking a flexible comparator as an example, the function and electrical performance of a flexible circuit are verified.(4) Taking a flexible amplifier circuit as an example, the flexible interconnection layout and wiring are simulated and verified.

关键词： flexible electronic design platform stretchable interconnect flexible device stretchable flexible electronic circuit stretchable flexible circuit layout wiring