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SSRN 2023年

作者： Liang, Ying Liu, Kang Liu, Benjian Li, Yicun Fan, Saifei Dai, Bing Zhang, Yumin Zhu, Jiaqi National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin150080 China Key Laboratory of Micro-systems and Micro-structures Manufacturing Ministry of Education Harbin150080 China of Unmanned Equipment & Al Zhongshan528400 China

Microwave plasma assisted chemical vapor deposition (MPCVD) is a technique for preparing high-quality diamonds. However, the low yield and easy bonding between particles to form films are drawbacks that in the preparation of nano-diamond (ND) particles. These issues are believed to be mainly caused by the adverse factors of substrate nucleation and continuous growth of particles. In this study, to inhibit these factors, diamond vapor phase nucleation (VPN) - growth plasma environment is achieved by adjusting the spatial distribution of the carbon and hydrogen groups in plasma. In this environment, NDs nucleate without using a seeded substrate, grow and fall on the disk isolated from its nucleation and growth environment. The dispersed particle density breaks through the highest value of the conventional theory of MPCVD NDs deposition by 2 orders of magnitude (~ 1010cm−2). Besides, we further analyzed and improved the VPN growth mechanism. This study opens up a new mode of using MPCVD, which can be used to grow dispersed NDs. The development and improvement of this method is expected to provide higher quality NDs for fine grinding, composite material reinforcement, and color center applications. © 2023, The Authors. All rights reserved.

关键词： Nucleation

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Ultra-fast synthesis and thermodynamic analysis of MoAlB by self-propagating high temperature combustion synthesis

arXiv

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arXiv 2022年

作者： Yin, Hang He, Xiaodong Song, Guangping Yu, Yongdong Zheng, Yongting Bai, Yuelei National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Centre for Composite Materials and Structures Harbin Institute of Technology Harbin150080 China

MoAlB as a typical member of the MAB phases has attracted much growing attention due to its unique properties. However, the low production of MoAlB powders limits its further development and potential applications. To respond this challenge, the ultra-fast preparation of high-purity MoAlB powders is achieved in a few seconds by self-propagating high temperature combustion synthesis (SHS) using the raw powder mixture at the atomic ratio of 1Mo/1.3Al/1B. The reaction mechanism in SHS process was obtained by analyzing the corresponding composition changes of starting materials. Furthermore, the thermodynamic prediction for the SHS reaction of Mo + (1+ y) Al + B = MoAlB + yAl is consistent with the present experiments, where the preparation of MoAlB also conforms to two common self-propagating conditions of SHS. Enthalpy vs temperature curve shows that the adiabatic temperature of the reaction decreases with increasing the amount of excuse Al, but increases when pre-heating the reactants. The thermodynamic calculation method also provides a new idea for the preparation of other MAB phases by SHS. © 2022, CC BY-NC-SA.

关键词： Temperature

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Microstructural Formation and Evolution of Near-Eutectic Al2o3-Zro2 Powders Prepared by a Rapid Cooling Technique: An Extended Composition Range for Complete Eutectic Microstructures Without Primary Dendrites

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SSRN 2022年

作者： Yuan, Yuchen Yu, Wanjun Zheng, Yongting Yu, Yongdong Liu, Xudong Yin, Hang National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Center for Composite Materials and Structures Harbin Institute of Technology Harbin150080 China

Regulation of eutectic compositions is a difficult challenge due to the limited formation range of this microstructure. Al2O3-ZrO2 powders were successfully prepared through a modified high-temperature melt-assisted air atomization technique. The high-temperature melt (3500 K) was obtained based on the exothermic reaction between Al and O2, which was subsequently atomized and quenched to form composite powders. Eutectic colonies with nanolamellae (62–79 nm) were observed in the as-prepared Al2O3-(28–58 mol%) ZrO2 powders. Importantly, the powders with ZrO2 contents of 38 mol% and 42 mol% showed complete eutectic microstructures without primary dendrites, which indicated an extended obtainable range deviating by ~4.9 mol% from the eutectic composition (CE). The microstructural formation mechanism was discussed based on solidification behavior analysis. Furthermore, the evolution of the microstructure and phase in Al2O3-42 mol% ZrO2 powders was investigated. This work provides a reference for the composition regulation of oxide eutectics. © 2022, The Authors. All rights reserved.

关键词： Eutectics

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Strong convergence of the adaptive Milstein method for nonlinear stochastic differential equations with piecewise continuous arguments

arXiv

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arXiv 2025年

作者： Zhang, Yuhang Song, Minghui Zhu, Jiaqi School of Astronautics Harbin Institute of Technology Harbin150080 China Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou450000 China School of Mathematics Harbin Institute of Technology Harbin150001 China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin150080 China

In this work, an adaptive time-stepping Milstein method is constructed for stochastic differential equations with piecewise continuous arguments (SDEPCAs), where the drift is one-sided Lipschitz continuous and the diffusion does not impose the commutativity condition. It is widely recognized that explicit Euler or Milstein methods may blow up when the system exhibits superlinear growth, and modifications are needed. Hence we propose an adaptive variant to deal with the case of superlinear growth drift coefficient. To the best of our knowledge, this is the first work to develop a numerical method with variable step sizes for nonlinear SDEPCAs. It is proven that the adaptive Milstein method is strongly convergent in the sense of Lp, p ≥ 2, and the convergence rate is optimal, which is consistent with the order of the explicit Milstein scheme with globally Lipschitz coefficients. Finally, several numerical experiments are presented to support the theoretical analysis. Copyright © 2025, The Authors. All rights reserved.

关键词： Stochastic systems

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Facile Polyimide-Coating-On-Aramid Nanofiber Strategy Toward Ultralight Organic Aerogels with Superior Multifunctional Properties

SSRN

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SSRN 2024年

作者： Wang, Xiaolei Zhao, Kunlong Cao, Wenxin Ji, Dongchao Ye, Zhijie Su, Zhenhua Gao, Ge Wang, Zhuochao Sun, Chunqiang Liu, Yingqi Zhang, Lan Zhang, Tianyu Li, Feiran Zhu, Jiaqi National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin150080 China Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou450000 China Key Laboratory of Micro-Systems and Micro-Structures Manufacturing Ministry of Education Harbin150080 China School of Mechatronics Engineering Harbin Institute of Technology Harbin150080 China

High-performance aerogels are highly desirable in the fields of thermal barriers, drug delivery, and mechanical cushions;however, most of the reported aerogels are limited by complex preparation processes and single functionality. To address such issues, in this study, we prepare a series of aramid nanofiber (ANF)/polyimide (PI) multifunctional composite organic aerogels via a facile polyimide-coating-on-aramid nanofiber (PCoA) strategy. This strategy utilizes PI to coat on the surface of ANFs and construct numerous mesopores within the ANF three-dimensional network skeleton to make the ANF/PI composite aerogels exhibit superior multifunctional properties, such as outstanding thermal and acoustic insulation, mechanical strength, thermal stability, flame retardancy, and hydrophobicity. In particular, the as-prepared composite aerogels with a PI content of 20 wt% exhibit a thermal conductivity of 23.20 mW/mK, which is lower than that of air, and their specific Young’s modulus reaches 32.57 MPa/(g/cm3), the highest among all previously reported organic aerogels, at a density of only 14.86 mg/cm3. The composite aerogels are destined to be extremely valuable as they can combine so many remarkable properties in a single package. Currently, the composite aerogels have been available in the form of ultrathin thermal insulation films at a thickness of only 100 μm, which can provide effective heat protection in microelectronic devices, and remain a terrific ability to operate under extreme conditions. Owing to these superior multifunctional properties, the ANF/PI composite aerogels show great potential for application in numerous fields, such as environmental governance, catalysis, energy storage, and aerospace. © 2024, The Authors. All rights reserved.

关键词： Polyimides

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Effect of T6 heat treatment on microstructure and mechanical properties of Hf-modified Al7075 alloy fabricated by laser powder bed fusion

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Materials Characterization 2025年 225卷

作者： Zhang, Yuankun Liu, Kan Shi, Pengju Jiang, Aoke Su, Yishi Luo, Fenghua Lin, Haoze Wang, Xinpeng Long, Yu School of Resources Environment and Materials Guangxi University Guangxi Nanning530004 China Institute of Laser Intelligent Manufacturing and Precision Processing School of Mechanical Engineering Guangxi University Guangxi Nanning530004 China State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai200240 China State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering Shanghai University Shanghai200444 China

Very recently, we have proposed a new Hf-modified Al7075 alloy, which was demonstrated to have good compatibility with laser powder bed fusion (LPBF) processing. The present work has further explored the response of the microstructure and mechanical properties of the alloy to a T6 heat treatment (solution treatment at 470 °C for 1 h + aging at 120 °C for 24 h). It was found that after the heat treatment, Al3Hf precipitates have experienced a huge change, from a spheroidal form with an L12 structure to a needle-like form with a D022 structure, whereas the grain morphology, size, orientation have little been altered. Meanwhile, the strength of the alloy has obviously been improved without losing much of the ductility after the heat treatment. The improvement of the strength is mainly attributed to the produced D022-Al3Hf particles, which have an unexpected coherent interface with the α-Al matrix, a large volume fraction, and a small radius of the repeated building blocks. © 2024

关键词： Microhardness

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Phase Engineering of Cu@Cu2o Core-Shell Nanospheres for Boosting Tandem Electrochemical Co2 Reduction to C2+ Products

SSRN

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SSRN 2023年

作者： Ye, Meng Shao, Tao Liu, Junyan Li, Chuanhao Song, Bo Liu, Shengwei School of Environmental Science and Engineering Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology Sun Yat-sen University Guangzhou510006 China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology Harbin150001 China Northwest Normal University China

Cu-based CO2 electrochemical reduction (CO2ER) is promising for reducing greenhouse gas emission and producing high-value multicarbon (C2+) chemicals and fuels. Unfortunately, the C2+ selectivity is still quite low. In this work, well-defined Cu@Cu2O core-shell nanospheres with time-dependent evolution of phase composition, crystallinity and morphology were specifically designed by a facile chemically induced self-transformation strategy. A maximum C2+ Faradaic efficiency (FE) exceeding 79%, including FEC2H4 reaching 44%, was achieved using phase-engineered Cu@Cu2O nanospheres. Based on the temperature-programmed desorption analyses and in-situ Raman spectroscopy, the adsorption behaviors of both CO2 reactant and *CO intermediate can be synergistically tuned by phase engineering of Cu@Cu2O nanospheres: Cu2O shell enhances *CO2 and *CO adsorption coverage, while porous Cu core concentrate and strengthens *CO intermediates for subsequent CO-CO coupling towards C2+ products. This work will shed new light on the phase engineering of Cu-based tandem electrocatalysts for tuning CO2/CO-catalyst interaction and modulating CO2ER processes and selectivity. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

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Effect of thickness on infrared optical property of VO2 film deposited by magnetron sputtering

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science China(Technological sciences) 2020年第8期63卷 1591-1598页

作者： YANG ZhenHuai YANG QiuLing YANG Lei DAI Bing XIA Fei WANG Peng GUO Shuai GAO Gang XU LiangGe ZHANG YuMin ZHU JiaQi National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150080China Key Laboratory of Micro-systems and Micro-structures Manufacturing Ministry of EducationHarbin 150080China Center of Analysis Measurement Harbin Institute of TechnologyHarbin 150080China

A series of VO2 films with different thicknesses(from about 25 nm to 250 nm)were prepared on sapphire substrates by radio frequency magnetron *** deposition times varied from 15 min to 150 *** metal to insulator transitions(MIT)of the films were *** optical transmittance of the films to infrared light(with a wavelength of 4.0μm)at room temperature(30℃)varied significantly with film thickness,ranging from 86.53%to 41.01%.The modulation property also changes with thickness,decreasing from 22.89%to 14.74%.The phase transition temperature remained approximately 70℃during heating,and approximately 53℃during cooling,despite a tenfold increase in the deposition time,and the resulting thickness of the *** spectroscopy of the films indicated that the intensities of the characteristic peaks corresponding to V2O5 increase with the increasing of film ***-dependent Raman spectroscopy indicated that the peaks corresponding to VO2 undergo reversible changes during heating and cooling of the films,while the peaks corresponding to V2O5 remain unchanged *** control of the V2O5 content of the films(by varying the duration of the deposition process)allows control over their transmittance and optical modulation properties without changes in the phase transition *** provides a new method of controlling the optical properties of these materials and shows promise for their potential applications in thermochromic windows.

关键词： Vanadium dioxide mid-infrared transmittance phase transition temperature magnetron sputtering

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Highly efficient removal of trace lead(Ⅱ)from wastewater by 1,4-dicarboxybenzene modified Fe/Co metal organic nanosheets

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Journal of Materials science & technology 2022年第3期98卷 212-218页

作者： Junmao Hong Le Kang Xiaofeng Shi Renbo Wei Xianmin Mai Duo Pan Nithesh Naik Zhanhu Guo School of Environment and Safety Engineering School of Materials Science and TechnologyInstitute of Advanced Energy Materials and SystemsNorth University of ChinaTaiyuanChina School of Chemical Engineering Northwest UniversityXi’an 710069China School of Urban Planning and Architecture Southwest Minzu UniversityChengdu 610041China Key Laboratory of Materials Processing and Mold(Zhengzhou University) National Engineering Research Center for Advanced Polymer Processing TechnologyMinistry of EducationZhengzhou UniversityZhengzhou 450000China Department of Mechanical&Manufacturing Engineering Manipal Institute of TechnologyManipal Academy of Higher EducationManipalKarnataka 576104India Integrated Composites Laboratory(ICL) Department of Chemical&Biomolecular EngineeringUniversity of TennesseeKnoxvilleTN 37996United States

A novel Fe/Co metal organic complex nanosheet modified by 1,4-dicarboxybenzene(BDC),i.e.,FeCo@BDC,was prepared,and highly efficient removal performance for trace lead(Ⅱ)(Pb^(2+))was demonstrated in the neutral aqueous *** removal rates were higher than 95%and the adsorption was equilibrated in 15 *** isotherms and kinetics for the adsorption Pb^(2+)by the FeCo@BDC adsorbents followed Langmuir model and pseudo-second-order model,*** maximum adsorption capacity was 220.48 mg g^(-1).The FeCo@BDC adsorbents also own a prominent regeneration *** prominent performance of in the removal of trace Pb^(2+)makes FeCo@BDC an ideal candidate as commercial adsorbent materials.

关键词： Metal organic complex Nanosheet Trace level Lead(Ⅱ) Adsorption

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Charge-redistribution in bimetallic oxides buried in microporous curled carbon for efficient nitrate electroreduction to ammonia

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science China Materials 2025年第2期68卷 472-482页

作者： Lituo Liu Hongliang Dong Sina Huang Nana Gao Leiqian Zhang Li-Ming Yang Jingwen Ba Johan Hofkens Markus Antonietti Tianxi Liu Feili Lai Zhihong Tian Engineering Research Center for Nanomaterials Henan UniversityKaifeng 475004China Center for High Pressure Science and Technology Advanced Research Shanghai 201203China Key Laboratory of Theoretical Chemistry of Environment Ministry of EducationSchool of ChemistrySouth China Normal UniversityGuangzhou 510006China Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringJiangnan UniversityWuxi 214122China School of Chemistry and Chemical Engineering Huazhong University of Science and TechnologyWuhan 430074China Department of Chemistry KU LeuvenCelestijnenlaan 200FLeuven 3001Belgium Department of Colloid Chemistry Max Planck Institute of Colloids and InterfacesPotsdam 14476Germany State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Electrochemical reduction from nitrate into ammonia is a chance for nitrate removal from drinking water,while at higher concentrations,this 8-electron reduction process could even become relevant for energy storage,high conversions and low onset potentials ***,we report the synthesis and analysis of a NiFe_(2)O_(4)/C-MS hybrid system made by a molten-salt strategy where the Ni-Fe oxide spinel nanoparticles act as the active center for electrochemical nitrate(NO_(3)−)reduction reaction,while the microporous carbon serves as a conductive support to form a cohesive electrode *** NiFe_(2)O_(4)/C-MS catalyst achieves a maximum NH3 yield rate of 5.4 mg mgcat.^(−1)h^(−1)and Faradaic efficiency of 98%at−0.6 V versus reversible hydrogen *** NiFe_(2)O_(4)nanoparticles buried into microporous carbon,the onset potential decreases *** propose that this reduction originates from charge redistribution in NiFe_(2)O_(4)in the electronic heterojunction with carbon,while enhanced electrolyte diffusion in microporous carbon facilitates high conversion *** functional theory calculations clarify the low energy barrier on NiFe_(2)O_(4),highlighting the essential role of Ni in activating Fe *** COMSOL Multiphysics simulations demonstrate that the microporous curled carbon accelerates NO_(3)−transport and enhances adsorption on the reactive *** work offers insights for designing carbon-based nanocomposites for efficient nitrate reduction electrocatalysis.

关键词： carbon-based nanocomposites bimetallic catalyst molten-salt strategy electrocatalytic nitrate reduction ammonia

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