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INTERAcTION OF PREcIPITATION AND REcRYSTALLIZATION IN RAPIDLY SOLIDIFIED cu-cr-Zr-Mg ALLOY

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Acta Metallurgica Sinica(English Letters) 1999年第3期12卷 273-275,576-277页

作者： Liu, P. Kang, B.X. cao, X.G. huang, J.L. Yin, B. gu, h.c. Xi'an Jiaotong Univ Xi'an China

The recrystallization process of a rapidly solidified cu-cr-Zr-Mg alloy during its aging was investigate experimentally. It was found that (1) upon aging, the precipitation process takes place prior to recrystallization for the cold-deformed cu-cr-Zr-Mg alloy produced by rapid solidification, and the precipitates have a restrained effect on the following recrystallization process; (2) the hindrance of the dispersed fine precipitates to the common recrystallization leads to the simultaneous in situ and discontinuous recrystallization; (3) the resolution of the precipitates in the front of migrating grain boundaries takes place during the nucleation and growth of recrystallization, wh.c. results in a supersaturation in the recrystallized zones, while the re-precipitation of the supersaturated solute atoms in vacancies further increases the dispersion hardening effect.

关键词： crystal microstructure Precipitation (chemical) Rapid solidification Recrystallization (metallurgy) Supersaturation

Stacking MoS_(2) flower-like microspheres on pomelo peels-derived porous carbon nanosheets for high-efficient X-band electromagnetic wave absorption

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Nano Research 2024年第3期17卷 1607-1615页

作者： Jia Zhao Zhe gu Qingguo Zhang college of chemistry and Materials Engineering Bohai UniversityJinzhou 121013China

The key to solve increasingly severe electromagnetic(EM)pollution is to explore sustainable,easily prepared,and cost-effective EM wave absorption materials with exceptional absorption ***,instead of anchoring on carbon materials in single layer,MoS_(2) flower-like microspheres were stacked on the surface of pomelo peels-derived porous carbon nanosheets(c)to fabricate MoS_(2)@c nanocomposites by a facile solvothermal *** wave absorption performances of MoS_(2)@c nanocomposites in X-band were systematically investigated,indicating the minimum reflection loss(RLmin)of-62.3 dB(th.c.ness of 2.88 mm)and effective absorption bandwidth(EAB)almost covering the whole X-band(th.c.ness of 2.63 mm)with the filler loading of only 20 wt.%.Superior EM wave absorption performances of MoS_(2)@c nanocomposites could be attributed to the excellent impedance matching characteristic and dielectric loss capacity(conduction loss and polarization loss).This study revealed that the as-prepared MoS_(2)@c nanocomposites would be a novel prospective candidate for the sustainable EM absorbents with superior EM wave absorption performances.

关键词： pomelo peels-derived porous carbon nanosheets(c) MoS_(2)@c nanocomposites stacked structure electromagnetic(EM)wave absorption

Layer hall effect induced by hidden Berry curvature in antiferromagnetic insulators

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National Science Review 2024年第2期11卷 15-23页

作者： Rui chen hai-Peng Sun Mingqiang gu chun-Bo hua Qihang Liu hai-Zhou Lu X.c.Xie Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology(SUSTech) International Quantum Academy Institute for Theoretical Physics and Astrophysics University of Würzburg School of Electronic and Information Engineering Hubei University of Science and Technology guangdong Provincial Key Laboratory of computational Science and Material Design Southern University of Science and Technology Shenzhen Key Laboratory of Quantum Science and Engineering International center for Quantum Materials School of PhysicsPeking University collaborative Innovation center of Quantum Matter cAS center for Excellence in Topological Quantum computation University of Chinese Academy of Sciences

The layer hall effect describes electrons spontaneously deflected to opposite sides at different layers, wh.c. has been experimentally reported in the MnBi2Te4thin films under perpendicular electric fields. here, we reveal a universal origin of the layer hall effect in terms of the so-called hidden Berry curvature, as well as material design principles. hence, it gives rise to zero Berry curvature in momentum space but non-zero layer-locked hidden Berry curvature in real space. We show that, compared to that of a trivial insulator, the layer hall effect is significantly enhanced in antiferromagnetic topological insulators. Our universal picture provides a paradigm for revealing the hidden physics as a result of the interplay between the global and local symmetries, and can be generalized in various scenarios.

关键词： layerhall effect hidden Berry curvature antiferromagnetic insulator axion insulator, quantum transport

Recent advances of versatile reagents as controllable building blocks in organic synthesis

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chinese chemical Letters 2024年第2期35卷 24-43页

作者： Shaomin chen Luigi Vaccaro Yanlong gu Key Laboratory of Material chemistry for Energy conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China Laboratory of Green S.O.c. Dipartimento di ChimicaBiologia e BiotecnologieUniversità degli Studi di PerugiaVia Elce di Sotto 8Perugia 06123Italy School of chemistry and chemical Engineering The Key Laboratory for Green Processing of Chemical Engineering of Xinjiang BingtuanShihezi UniversityShihezi 832004China

Diversity-oriented synthesis is a powerful and interesting synthetic tool for the rapid construction of structurally complex and privileged scaffolds from readily accessible starting *** date,diversity-oriented synthesis mostly relies on the employment of versatile *** reagents can be regulated as controllable and flexible building blocks for multipurpose *** the past decade,a variety of multifunctional reagents have been ***,most versatile reagents usually need multi-step synthesis,thus restricting their wide application to a large *** terms of the practicalities and universalities,we prefer to pay more attention to the utilization of simple and practical versatile reagents with multiple reactivities,mainly including atropaldehyde acetals,aryl methyl ketones,vinylene carbonate,vinyl azides,aryldiazonium salts,rongalite,halodifluoromethyl *** importantly,these versatile reagents can also play different roles simultaneously in the same reaction,in wh.c. their different reactivities are converged into the final target *** strategy can not only offer more possibilities for the synthesis of several active pharmaceutical ingredients,but also minimize the occurrence of some side reactions by lessening the varieties of ***,a perspective is given at the end of this review.

关键词： Versatile reagents Divergent synthesis Dual synthons Bond cleavage Tandem reactions

Grading of products utilizing bamboo as a substitute for plastic based on environmental effects

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Science china Earth Sciences 2024年第9期67卷 2989-2998页

作者： Meng ZhANG guomo ZhOU Lei gu Wenshuo WANG college of Forestry Beijing Forestry UniversityBeijing 100083China Key Laboratory of carbon cycling in Forest Ecosystems and carbon Sequestration of Zhejiang Province Zhejiang A&F UniversityHangzhou 311300China

To achieve sustainable development goals,mitigate plastic pollution,and promote eco-friendly products,it is crucial to identify key products in the bamboo as a substitute for plastic(BSP)industry and assess their environmental *** study proposed a novel evaluation method for the environmental effect of bamboo as a substitute for plastic(EBSP).It focused on the contributions of BSP products in reducing plastic pollution and greenhouse gas *** established a set of EBSP evaluation indicators and developed a grading model,evaluating 30 typical BSP products across six *** results showed that the EBSP evaluation model,based on the emission reduction rate of substitution(ERRS),substitution rate of material(SRM),and product renewal ratio(PRR),can accurately quantify the environmental benefits of BSP *** model has successfully facilitated precise quantification of the EBSP and established a rational and effective grading system for BSP *** results also demonstrated that the average EBSP ranking across the six categories of BSP products,in descending order,is:disposable bamboo products,bamboo household goods,bamboo packaging products,bamboo engineering materials,bamboo furniture products,and bamboo craft ***,disposable bamboo products scored an EBSP 1.96 times the overall average,indicating significant environmental *** PRR emerged as a critical factor influencing *** BSP products with the same lifespan,those with higher substitution emission reduction efficiency offered more pronounced environmental ***,the BSP industry should strategically prioritize disposable bamboo products,such as bamboo toothbrushes,cutlery,and lunch *** products should be the primary focus of policy support and central to efforts in product development,design innovation,and market promotion.

关键词： Bamboo as a substitute for plastic Bamboo products Substitution emission reduction Environmental benefits Gradingevaluation

Small-sized Ni-co/Mo_(2)c/co_(6)Mo_(6)c_(2)@c for efficient alkaline and acidic hydrogen evolution reaction by an anchoring calcination strategy

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Frontiers of chemical Science and Engineering 2024年第5期18卷 95-103页

作者： Jianxia gu Ying Zhu haiyan Zheng chunyi Sun Zhongmin Su Department of chemistry Xinzhou Normal UniversityXinzhou 034000China School of chemistry Northeast Normal UniversityChangchun 130024China

A novel,cheap and highly efficient Ni-co/Mo_(2)c/co_(6)Mo_(6)c_(2)@c nanocomposite has been successfully constructed through simple one-step carbonization method in a nitrogen *** in the precursor can effectively anchor molybdenum-based Keggin-type polyoxometallate and Nico-layered double hydroxide through electrostatic and coordination interactions,wh.c. avoids the aggregation of catalyst particles during the pyrolysis *** optimization,the obtained Ni-co/Mo_(2)c/co_(6)Mo_(6)c_(2)@c possesses small size(3-8 nm),large specific surface area and hierarch.c.l pore *** importantly,Ni-co/Mo_(2)c/co_(6)Mo_(6)c_(2)@c presents remarkable hydrogen evolution reaction activity with low overpotentials in 0.5 mol·L^(-1)h_(2)SO_(4)(102.3 mV)and 1 mol·L^(-1)KOh(95 mV)to afford the current density of 10 mA·cm^(-2),as well as small Tafel slopes of 82.49 and 99.92 mV·dec^(-1),***,this catalyst also shows outstanding stability for 12 h without a significant change in current *** excellent catalytic performance of Ni-co/Mo_(2)c/co_(6)Mo_(6)c_(2)@c can put down to the synergistic effect between multiple components and the small size of the *** work provides unique insights into the preparation of efficient transition metal-based catalysts for hER.

关键词： polyoxometallates layered double hydroxide transition metal-based electrocatalysts hydrogen evolution reaction

Effect of fore/aft-loaded rotor on compressor stability under inlet circumferential distortion

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chinese Journal of Aeronautics 2024年第5期37卷 199-213页

作者： Dakun SUN Benhao gu Fangfei NING Dengke XU Xiaofeng SUN School of Energy and Power Engineering Beihang UniversityBeijing 102206China Research Institute of Aero-engine Beihang UniversityBeijing 102206China

A modified small perturbation stability prediction model for axial compressors with.c.rcumferential inlet distortions is established and applied to investigate the effect of fore/aft-loaded rotor on compressor stability under circumferentially distorted inlet *** inlet total pressure distribution downstream of the distortion screen is measured in experiments and employed for simulations wh.c. are implemented via time-space spectral *** stall inception prediction results via the stability model indicate that the compressor with aft-loaded rotor not only performs better in terms of stability under uniform inlet,but also maintains a larger stability margin under circumferentially distorted *** experiments for compressors with fore-loaded and aft-loaded rotor are respectively carried *** results validate the reliability of numerical simulations and the predicted conclusion that the aft-loaded rotor is beneficial for compressor ***,the ability of the developed theoretical model for compressor stability prediction under circumferential distortions is *** addition,dynamic pressure signals at rotor tip measured in experiments illustrate that the circumferential distortion has little effect on the compressor stall pattern.

关键词： Axial compressor stability Inlet distortion Blade loading Small perturbation Time-space spectral method

Ultrahigh performance passive radiative cooling by hybrid polar dielectric metasurface thermal emitters

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Opto-Electronic Advances 2024年第4期7卷 17-25页

作者： Yinan Zhang Yinggang chen Tong Wang Qian Zhu Min gu Institute of Photonic chips University of Shanghai for Science and TechnologyShanghai 200093China centre for Artificial-Intelligence Nanophotonics School of Optical-Electrical and Computer EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China

Real-world passive radiative cooling requires highly emissive,selective,and omnidirectional thermal emitters to maintain the radiative cooler at a certain temperature below the ambient temperature while maximizing the net cooling *** various selective thermal emitters have been demonstrated,it is still challenging to achieve these conditions sim-ultaneously because of the extreme difficulty in controlling thermal emission of photonic structures in *** we demonstrated hybrid polar dielectric metasurface thermal emitters with machine learning inverse design,en-abling a high emissivity of~0.92 within the atmospheric transparency window 8-13μm,a large spectral selectivity of~1.8 and a wide emission angle up to 80 degrees,*** selective and omnidirectional thermal emitter has led to a new record of temperature reduction as large as~15.4°c under strong solar irradiation of~800 W/m2,signific-antly surpassing the state-of-the-art *** designed structures also show great potential in tackling the urban heat island effect,with modelling results suggesting a large energy saving and deployment area *** research will make significant impact on passive radiative cooling,thermal energy photonics and tackling global climate change.

关键词： radiative cooling dielectric metasurfaces machine learning thermal emitters

Built-in electric field induced S-scheme g-c_(3)N_(4)homojunction for efficient photocatalytic hydrogen evolution:Interfacial engineering and morphology control

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Nano Research 2024年第6期17卷 4961-4970页

作者： Yongpan gu Yike Li haoqiang Feng Yanan han Zhongjun Li college of chemistry Zhengzhou UniversityZhengzhou 450001China

S-scheme possesses superior redox capabilities compared with the II-scheme,providing an effective method to solve the innate defects of g-c_(3)N_(4)(cN).In this study,S-doped g-c_(3)N_(4)/g-c_(3)N_(4)(ScN-tm/cN)S-scheme homojunction was constructed by rationally integrating morphology control with interfacial engineering to enhance the photocatalytic hydrogen evolution ***-situ Kelvin probe force microscopy(KPFM)confirms the transport of photo-generated electrons from cN to *** functional theory(DFT)calculations reveal that the generation of a built-in electric field between ScN and cN enables the carrier separation to be more efficient and *** transient absorption spectrum(fs-TAS)indicates prolonged lifetimes of ScN-tm/cN_(3)(τ1:9.7,τ2:110,andτ3:1343.5 ps)in comparison to those of cN(τ1:4.86,τ2:55.2,andτ3:927 ps),signifying that the construction of homojunction promotes the separation and transport of electron hole pairs,thus favoring the photocatalytic *** visible light irradiation,the optimized ScN-tm/cN_(3)exhibits excellent photocatalytic activity with the hydrogen evolution rate of 5407.3μmol·g^(−1)·h^(−1),wh.c. is 20.4 times higher than that of cN(265.7μmol·g^(−1)·h^(−1)).Moreover,the homojunction also displays an apparent quantum efficiency of 26.8%at 435 nm as well as ultra-long and ultra-stable cycle *** work offers a new strategy to construct highly efficient photocatalysts based on the metal-free conjugated polymeric cN for realizing solar energy conversion.

关键词： homojunction built-in electric field morphology control interfacial engineering carrier separation