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Correlating dynamic relaxation and viscoelasticity in metallic glasses

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 81-90页

作者： Guanghui xing Qi Hao Fan Zhu Yun-Jiang Wang yong Yang Hidemi Kato Eloi Pineda Si Lan JiChao Qiao School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Department of Mechanical Engineering College of EngineeringCity University of Hong KongHong Kong 999077China Department of Materials Science and Engineering College of EngineeringCity University of Hong KongHong Kong 999077China Institute for Materials Research Tohoku UniversitySendai 980-8577Japan Department of Physics Institute of Energy TechnologiesUniversitat Politècnica de CatalunyaBarceona 9Spain School of Material Science and Engineering Herbert Gleiter Institute of NanoscienceNanjing University of Science and Technology.Nanjing 210094China State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment Northwestern Polytechnical UniversityXi'an 710072China

Relaxation dynamics,essential for the structural evolution of non-equilibrium systems like glassy materials,remain ***,we explore relaxation dynamics and viscoelastic properties in three types of metallic glasses with distinctβrelaxation *** systems with significantβrelaxation,stress relaxation and creep experiments reveal a transition from two-step to one-step relaxation with rising ***,such a phenomenon is absent in systems with weakerβ*** model the two-step relaxation process using a double Kohlrausch-Williams-Watts equation,and the obtained relaxation times elegantly adhere to the Arrhenius *** combining fitted activation energies with theoretical analysis,we conclusively attribute these relaxation processes toβrelaxation andαrelaxation,***,we analyze the relaxation time spectra of two processes and establish a comprehensive picture linking dynamic relaxation with *** study provides new strategies for probing the complex relaxation behaviors of glasses from the perspective of viscoelasticity.

关键词： creep relaxation glasses

Unveiling optical anisotropy in disrupted symmetry WSe_(2)/SiP heterostructures

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Nano Research 2024年第9期17卷 8585-8591页

作者： Biqi hu xing Xie Xinyu Ouyang Junying Chen Shaofei Li Jun He Zongwen Liu Jian-Tao Wang Yanping Liu Institute of Quantum Physics School of PhysicsCentral South University932 South Lushan RoadChangsha 410083China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South University932 South Lushan RoadChangsha 410083China School of Chemical and Biomolecular Engineering The University of SydneyNSW 2006Australia The University of Sydney Nano Institute The University of SydneyNSW 2006Australia Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China Shenzhen Research Institute of Central South University Shenzhen 518000China

Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered considerable attention for their promising applications in sensors and optoelectronic devices,owing to their exceptional optical,electronic,and optoelectronic ***,the inherent high symmetry of TMD lattices imposes limitations on their functional ***,we present a strategy to disrupt the C_(3)rotational symmetry of monolayer WSe_(2)by fabricating a heterostructure incorporating WSe_(2)and SiP *** comprehensive experimental investigations and first-principle calculations,we elucidate that in the WSe_(2)/SiP heterostructure,excitons-both neutral and charged-emanating from WSe_(2)exhibit pronounced anisotropy,which remains robust against temperature ***,we observe an anisotropic ratio reaching up to 1.5,indicating a substantial degree of ***,we demonstrate the tunability of exciton anisotropy through the application of a magnetic field,resulting in a significant reduction in the anisotropic ratio with increasing field strength,from 1.57 to ***,the change in heterojunction anisotropy ratio reaches 24.8%as the magnetic field *** findings elucidate that the perturbation of the C_(3)rotational symmetry of the WSe_(2)monolayer arises from a non-uniform charge density distribution within the layer,exhibiting mirror *** results underscore the potential of heterostructure engineering in tailoring the properties of isotropic materials and provide a promising avenue for advancing the application of anisotropic devices across various fields.

关键词： symmetry breaking heterostructure engineering anisotropy optical spectroscopy

Microstructure and magnetocaloric properties of melt-extracted SmGdDyCoAl high-entropy amorphous microwires

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Rare Metals 2024年第3期43卷 1234-1242页

作者： Shi-Jie Wei Hong-Xian Shen Lun-yong Zhang Lin Luo Xin-xing Tang Jian-Fei Sun Xiao-Qing Li School of Materials Science and Engineering Harbin Institute of TechnologyHarbin150001China Applied Materials Physics Department of Materials Science and EngineeringKTH-Royal Institute of Technology10044StockholmSweden

This paper presents a systematic investigation of the microstructure and magnetocaloric properties of melt-extracted Sm_(20)Gd_(20)Dy_(20)Co_(20)Al_(20)high-entropy *** fabricated wires exhibited an amorphous structure,and the temperature interval of the undercooled liquid AT was 45 *** microwires underwent a second-order magnetic transition from a ferromagnetic to a paramagnetic state near the Curie temperature(T_(C)=52 K),The maximum magnetic entropy change(-ΔS_M^(max)),the relative cooling power and the refrigeration capacity reached 6.34 J·kg^(-1)·K^(-1).422.09 J·kg^(-1)and 332.94 J·kg^(-1),respectively,under a magnetic field change of 5 *** addition,the temperature-averaged entropy changes with two temperature lifts(3 and 10 K)were 6.32 and 6.27 J·kg^(-1)·K^(-1),*** good magnetocalorie performance highlights the significant potential for the Sm_(20)Gd_(20)Dy_(20)Co_(20)Al_(20)microwires to be used as magnetic refrigerant materials in low-temperature region *** work will serve as a valuable reference for future investigations on low-temperature high-entropy magnetocaloric materials.

关键词： Melt-extraction High-entropy amorphous microwires Magnetocaloric effect Magnetic refrigeration

3D-structured carbon nanotube fibers as ultra-robust fabrics for adaptive electromagnetic shielding

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Nano Research 2024年第9期17卷 8521-8530页

作者： Dongping Li Ping Wang Yuanyuan Li Zhenzhong yong Kunjie Wu Yan Zhang Jin Wang Dongmei hu Key Laboratory of Multifunctional and Smart Systems Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China College of Textile and Clothing Engineering of Soochow University Suzhou 215021China

Wireless communication technology is indispensable in our daily lives,but it also results in serious electromagnetic radiation ***,developing smart electromagnetic interference shielding materials with adjustable electromagnetic wave(EMW)responses holds significant promise for future electromagnetic shielding *** this study,we propose an electromagnetic shielding switch(ESS)characterized by tunable electromagnetic shielding performance achieved by fabricating a three-dimensional(3D)carbon nanotube-based spacer fabric(CNT-SF)and modifying CNT-SF with chemical vapor deposition(CCNT-SF).The CCNT-SF displays direction-dependent electrical conductivity by manipulating the warp and weft density,measuring 128 S/m transversely and 447 S/m *** characteristic allows the CCNT-SF to transmit or shield EMW by adjusting the angle of EMW incidence through fabric rotation,resulting in anisotropic electromagnetic shielding performance(33 dB transversely and 87 dB vertically).This feature enables switchable shielding with an on/off ratio of ***,the unique 3D structure confers excellent mechanical properties on the fabric,with compressive strength reaching 120 *** a flexible,lightweight,and mechanically robust ESS,the CCNT-SF holds promising prospects for mitigating the challenges of increasingly severe and intricate electromagnetic environments.

关键词： carbon nanotube spacer fabric electromagnetic shielding impact resistance joule heating electromagnetic shielding switch

Red algal evidence for a marine regression during closure of the Paleo-Asian Ocean in the Junggar Basin and its linkage to hydrocarbon generation

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Science China Earth Sciences 2024年第9期67卷 2845-2863页

作者： Ruijie ZHANG Jian CAO Lizeng BIAN Wenxuan hu Liuwen XIA Bin ZHANG yong TANG Wenjun HE School of Earth Sciences and Engineering Nanjing UniversityNanjing 210023China PetroChina Xinjiang Oilfield Company Karamay 834000China

The closure of the Paleo-Asian Ocean was a significant geological event in northern Pangea during the *** had a significant effect on climate,biota,and environmental conditions of the Late Paleozoic Ice Age,and resulted in the development of vast energy *** paper reports on the first discovery of marine red algal fossils in the Junggar Basin and its linkage to hydrocarbon *** algae occur mainly in the Fengcheng Formation(ca.300 Ma)and provide direct fossil evidence for closure of the Paleo-Asian *** red algal fossils contain well-preserved reproductive organs,such as cystocarps and *** concentrations of C_(27) steranes(C_(27) regular steranes/sum of C_(27)-C_(29) regular steranes×100=14.30%-21.30%)and the marine biomarker 24-n-propylcholesterane(C_(30) diasterane[βα20S]/sum of C_(27)-C_(30) diasteranes[βα20S]×100=1.15%-1.85%)were detected in the red-algae-bearing hydrocarbon source *** experiments that simulate hydrocarbon generation show that the oil generation potential of the red-algae-bearing source rocks is 363.71 mg g^(-1) total organic *** result,combined with oil-source rock correlations,indicates these rocks contributed to the formation of oil and gas resources,particularly in the marginal areas of the *** lake basin inherited the water and biological conditions of the Paleo-Asian Ocean during a marine regression,which was an important factor in the development of these high-quality hydrocarbon source rocks in an alkaline saline *** results advance our understanding of the evolution of the Paleo-Asian Ocean,interactions between the ocean and a lake during the deposition of terrestrial hydrocarbon source rocks,and whether red algae can effectively generate hydrocarbons.

关键词： Biotic precursor 24-n-propylcholesterane Regressive lake basin Fengcheng Formation Junggar Basin

Secure symbol level precoding for cell-free network based on band-region constraint of the eavesdropper’s receiving signal

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High Technology Letters 2024年第3期30卷 304-309页

作者： LI Zewen JIN yong FU Chunling PENG Xin hu Zhentao School of Artifical Intelligence Henan UniversityZhengzhou 450000P.R.China School of Physics and Electronics Henan UniversityKaifeng 475000P.R.China

A symbol level secure precoding scheme based on band-region constraint of the eavesdropper’s receiving signal is proposed to enhance the energy efficiency of cell-free multiple-input multiple-output(MIMO)networks in the presence of an eavesdropper while guaranteeing the quality of service(QoS)of user and the security of ***,to lighten its high computational complexity,original problem is divided into several cascade sub-problems firstly,and then those sub-problems are handled by combining Lagrangian dual function and improved Hooke-Jeeves method *** ex-periment with other secure symbol-level precoding schemes demonstrate that proposed scheme can achieve the lower power consumption with almost same symbol error rate and QoS of user.

关键词： cell-free symbol-level precoding(SLP) physical layer security(PLS) multi-ple-input multiple-output(MIMO) band-region constraint

Application of a concrete thermal pile in cooling the warming permafrost under climate change

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Advances in Climate Change Research 2024年第1期15卷 170-183页

作者： Yun-hu SHANG Fu-Jun NIU Guo-Yu LI Jian-Hong FANG Ze-yong GAO State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Da xing'anling Observation and Research Station of Frozen-Ground Engineering and Environment Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesJagdaqi 165000China Qinghai Research Institute of Transportation Xining 810008China

Permafrost degradation caused by climate warming is posing a serious threat to the stability of cast-in-place pile foundations in warm permafrost *** cold energy can be effectively utilized by two-phase closed thermosyphons(TPCTs)to cool the ***,we installed TPCTs in a cast-in-place pile foundation to create a unique structure called a thermal pile,which effectively utilizes the TPCTs to regulate ground *** we conducted a case study and numerical simulation to exhibit the cooling performance,and optimize the structure of the thermal *** purpose of this study is to promote the application of thermal piles in unstable permafrost *** on the findings,the thermal pile operated for approximately 53%of the entire year and effectively reduced the deep ground temperature at a rate of at least-0.1℃per ***,it successfully raised the permafrost table that is 0.35 m shallower than the natural ground *** characteristics prove highly beneficial in mitigating the adverse effects of permafrost degradation and enhancing infrastructure *** the length of the condenser section and the diameter of the TPCT in a suitable manner can effectively enhance the cooling capability of the thermal pile and ensure the long-term mechanical stability of the pile foundation even under climate warming.

关键词： Heat transfer Cold energy Warm permafrost Two-phase closed thermosyphons Cast-in-place pile foundation

Suppressing the Undesirable Energy Loss in Solution-Processed Hyperfluorescent OLEDs Employing BODIPY-Based Hybridized Local and Charge-Transfer Emitter

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Energy & Environmental Materials 2024年第2期7卷 372-380页

作者： Xuewei Nie Zafar Mahmood Denghui Liu Mengke Li Dehua hu Wencheng Chen Longjiang xing Shijian Su Yanping huo Shaomin Ji School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices South China University of TechnologyGuangzhou 510640China

Hyperfluorescent organic light-emitting diodes(HF-OLEDs)approach has made it possible to achieve excellent device performance and color purity with low roll-off using noble-metal-free pure organic *** significant progress,the performance of HF-OLEDs is still unsatisfactory due to the existence of a competitive dexter energy transfer(DET)*** this contribution,two boron dipyrromethene(BODIPY)-based donor-acceptor emitters(BDP-C-Cz and BDP-N-Cz)with hybridized local and charge transfer characteristics(HLCT)are introduced in the HF-OLED to suppress the exciton loss by dexter mechanism,and a breakthrough performance with low-efficiency roll-off(0.3%)even at high brightness(1000 cd m^(-2))is *** is demonstrated that the energy loss via the DET channel can be suppressed in HF-OLEDs utilizing the HLCT emitter,as the excitons from the dark triplet state of such emitters are funneled to its emissive singlet state following the hot-exciton *** developed HF-OLED device has realized a good maximum external quantum efficiency(EQE)of 19.25%at brightness of 1000 cd m^(-2)and maximum luminance over 60000 cd m^(-2),with an emission peak at 602 nm and Commission International de L'Eclairage(CIE)coordinates(0.57,0.41),which is among the best-achieved results in solution-processed *** work presents a viable methodology to suppress energy loss and achieve high performance in the HF-OLEDs.

关键词： BODIPY hyperfluorescence organic light-emitting diodes solution-process

Two new high-temperature molecular ferroelectrics[1,5-3.2.2-Hdabcn]X(X=ClO_(4)^(-),ReO_(4)^(-))

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Chinese Chemical Letters 2024年第6期35卷 234-238页

作者： Keke Han Wenjun Rao Xiuli You Haina Zhang xing Ye Zhenhong Wei hu Cai School of Chemistry and Chemical Engineering Nanchang UniversityNanchang 330031China Jiangxi Key laboratory of Organic Chemistry Jiangxi Science and Technology Normal UniversityNanchang 330013China

Molecular ferroelectrics have attracted much attention because of their excellent piezoelectricity,mechanical workability,and second harmonic ***,we successfully prepared two molecular ferroelectrics[1,5-3.2.2-Hdabcn]X(X=ClO_(4)^(-),1;ReO_(4)^(-),2)by reactions of a quasi-spherical amine 1,5-diazabicycle[3.2.2]nonane(1.5-3.2.2-dabcn)with HX aqueous *** 1 and 2 undergo hightemperature phase transitions at 381 K(1)and 396 K(2).Before and after the phase transition,they crystallize in the polar point group mm2,and the centrosymmetric point groups mmm and 4/mmm,*** to Aizu rules,these two compounds experience mmm Fmm2 and 4/mmm Fmm2 type ferroelectric phase transitions,*** ferroelectricity of both compounds is well expressed in their polycrystalline film at room temperature with low coercive voltages of 13 V for 1 and 25 V for *** piezoelectric force microscopy(PFM),the 180°anti-parallel ferroelectric domains and the reversible polarization switching can be clearly observed in 1 and *** high-temperature molecular ferroelectric material has great application potential in flexible materials,biomechanics,intelligent wearables and other fields.

关键词： Ferroelectric domains Quasi-spherical amine Phase transition Polarization