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Optical Transient Source AT2021lfa:A Possible“Dirty Fireball”

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Research in Astronomy and Astrophysics 2024年第4期24卷 124-133页

作者： Xue-Mei Ye Da-Ming Wei yi-Ming Zhu Zhi-Ping jin Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China National Astronomical Observatories/Nanjing Institute of Astronomical Optics&Technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of Astronomical Optics&Technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China

AT2021lfa,also known as ZTF21aayokph,was detected by the Zwicky Transient Facility on 2021 May 4,a 05:34:48 ***-up observations were conducted using a range of ground-based optical telescopes,as wel as Swift/XRT and VLA ***2021lfa is classified as an“orphan afterglow”candidate due to its rapid flux decline and its reddened color(g-r=0.17±0.14 mag).For an optical transient source without promp gamma-ray detection,one key point is to determine its burst *** we measure the burst time through fitting the initial bump feature of AT2021lfa and obtain its burst time as 2021 May 3,at 22:09:50 *** afterglowpy,we model the multi-band afterglow of AT2021lfa and find that the standard model canno reproduce the late radio observations *** that the microphysical parameters ε_(e),ε_(B)(the energy fraction given to electrons and magnetic field),andξN(the fraction of accelerated electrons)may vary with time we then model the afterglow of AT2021lfa taking into account the temporal evolution of the physical parameters ε_(e),ε^(B),and ξ_(N) and find in this case the multi-wavelength observations can be reproduced *** initial Lorentz factor of AT2021lfa can be estimated from the peak time of the early afterglow,which yields a value of about 18 suggesting that AT2021lfa should be classified as a“dirty fireball.”From the upper limit for the prompt emission energy of AT2021lfa,we obtain that the radiation efficiency is less than 0.02%,which is much smaller than that of ordinary gamma-ray bursts(GRBs).It is also interesting that the fitted values of jet angle and viewing angle are very large,θ_(c)~0.66 rad,θ_(v)~0.53 rad,which may lead to the low Lorentz factor and radiation *** compared with GRB afterglow samples,it is evident that the onset bump timescale of AT2021lfa satisfies the empirical relationships observed in GRB ***,the luminosity of AT2021lfa falls within the range of observations for GRB samples;howeve

关键词： gamma-rays:ISM methods:numerical radiation mechanisms:non-thermal

Mechanism of high Li-ion conductivity in poly(vinylene carbonate)-poly(ethylene oxide)cross-linked network based electrolyte revealed by solid-state NMR

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Journal of Energy Chemistry 2024年第6期93卷 377-383,I0010页

作者： Fan Li Tiantian Dong yi ji Lixin Liang Kuizhi Chen Huanrui Zhang Guanglei Cui Guangjin Hou State Key Laboratory of Catalysis Dalian National Laboratory for Clean EnergyCollaborative Innovation Center of Chemistry for Energy MaterialsDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina University of Chinese Academy of Sciences Beijing 100049China Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101ShandongChina

Solid polymer electrolytes(SPEs)have become increasingly important in advanced lithium-ion batteries(LIBs)due to their improved safety and mechanical properties compared to organic liquid ***-linked polymers have the potential to further improve the mechanical property without trading off Li-ion *** this study,focusing on a recently developed cross-linked SPE,i.e.,the one based on poly(vinylene carbonate)-poly(ethylene oxide)cross-linked network(PVCN),we used solid-state nuclear magnetic resonance(NMR)techniques to investigate the fundamental interaction between the chain segments and Li ions,as well as the lithium-ion *** utilizing homonuclear/heteronuclear correlation,CP(cross-polarization)kinetics,and spin-lattice relaxation experiments,etc.,we revealed the structural characteristics and their relations to lithium-ion *** is found that the network formation prevents poly(ethylene oxide)chains from crystallization,which could create sufficient space for segmental tumbling and Li-ion co nductio *** such,the mechanical property is greatly improved with even higher Li-ion mobilities compared to the poly(vinylene carbonate)or poly(ethylene oxide)based SPE analogues.

关键词： ssNMR Lithium-ion mobility Cross-link Solid polymer electrolyte

Rapid fabrication of modular 3D paper-basedmicrofluidic chips using projection-based 3D printing

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Bio-Design and Manufacturing 2024年第5期7卷 611-623页

作者： Mingjun Xie Zexin Fu Chunfei Lu Sufan Wu Lei Pan Yong He yi Sun ji Wang Plastic and Reconstructive Surgery Center Department of Plastic and Reconstructive SurgeryZhejiang Provincial People’s HospitalAffiliated People’s HospitalHangzhou Medical CollegeHangzhou 310014China State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou 310058China Key Laboratory of Materials Processing and Mold Zhengzhou UniversityZhengzhou 450002China Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province College of Mechanical EngineeringZhejiang UniversityHangzhou 310058China Cancer Center Zhejiang UniversityHangzhou 310058China

Paper-based microchips have different advantages,such as better biocompatibility,simple production,and easy handling,making them promising candidates for clinical diagnosis and other *** study describes amethod developed to fabricate modular three-dimensional(3D)paper-based microfluidic chips based on projection-based 3D printing(PBP)technology.A series of two-dimensional(2D)paper-based microfluidic modules was designed and *** evaluating the effect of exposure time on the accuracy of the flow channel,the resolution of this channel was experimentally ***,several 3D paper-based microfluidic chips were assembled based on the 2D ones using different methods,with good channel ***-based 2D and hydrogel-based 3D cell culture systems based on 3D paper-based microfluidic chips were verified to be ***,by combining extrusion 3D bioprinting technology and the proposed 3D paper-based microfluidic chips,multiorgan microfluidic chips were established by directly printing 3D hydrogel structures on 3D paperbased microfluidic chips,confirming that the prepared modular 3D paper-based microfluidic chip is potentially applicable in various biomedical applications.

关键词： Paper-based microfluidic chip Projection-based 3D printing(PBP) Modularization Cell culture

Advances of machine learning in materials science: Ideas and techniques

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Frontiers of physics 2024年第1期19卷 155-194页

作者： Sue Sin Chong yi Sheng Ng Hui-Qiong Wang jin-Cheng Zheng Department of New Energy Science and Engineering Xiamen University MalaysiaSepang 43900Malaysia Engineering Research Center of Micro-nano Optoelectronic Materials and Devices Ministry of EducationFujian Key Laboratory of Semiconductor Materials and ApplicationsCI Center for OSEDand Department of PhysicsXiamen UniversityXiamen 361005China

In this big data era, the use of large dataset in conjunction with machine learning (ML) has been increasingly popular in both industry and academia. In recent times, the field of materials science is also undergoing a big data revolution, with large database and repositories appearing everywhere. Traditionally, materials science is a trial-and-error field, in both the computational and experimental departments. With the advent of machine learning-based techniques, there has been a paradigm shift: materials can now be screened quickly using ML models and even generated based on materials with similar properties;ML has also quietly infiltrated many sub-disciplinary under materials science. However, ML remains relatively new to the field and is expanding its wing quickly. There are a plethora of readily-available big data architectures and abundance of ML models and software;The call to integrate all these elements in a comprehensive research procedure is becoming an important direction of material science research. In this review, we attempt to provide an introduction and reference of ML to materials scientists, covering as much as possible the commonly used methods and applications, and discussing the future possibilities.

关键词： machine learning materials science

Research paper Air atmosphere available fast one-pot synthesis of VO_(2)nanoparticles with excellent thermochromic properties by a novel liquid-shielding method

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Journal of Materiomics 2024年第1期10卷 17-26页

作者： Zhi Cao jin Li Chunhui Zhang Ke jiao Yunxiang Chen yifei Liu Xinghui Hou Haipeng ji Liying Zhang Shasha yi Yu Wang Zhang Chen Yanfeng Gao Zongtao Zhang School of Materials Science and Engineering Zhengzhou UniversityKexue Ave 100Zhengzhou450001China School of Materials Science and Engineering Shanghai UniversityShangda Rd 99Shanghai200444China

As a typical strongly correlated transition oxide,vanadium dioxide(VO_(2))based nanomaterials have drawn many research attentions these years due to the giant metal-to-insulator phase transition(MIPT)at around 68℃.However,due to the complexities of the V-O system and interplays between various vanadium oxide phases,the synthesis of high-quality VO_(2)nanopowders is still fraught with many challenges,especially in air *** this paper,we report a novel air atmosphere available liquid-shielding synthesis method for thermochromic VO_(2)nanoparticles,by using low-eutectic molten-salt(LiCl-KCl)as the liquid-state air-insulation medium at elevated temperature and high-pressure pressed VOSO_(4)-KCl pillars immersed in these liquid salts as the *** amounts of glucose are added to introduce a slight reductive environment,and well dispersed VO_(2)nanoparticles with excellent ther-mochromic properties can be directly synthesized at an ultra-low temperature of 375℃.This feasible and atmosphere-available mass-production method is rarely reported in the related fields,which may provide a novel protocol strategy for the synthesis of high performance thermochromic VO_(2)and other functional oxide powders.

关键词： Vanadium dioxide Nanoparticle Molten salt Liquid shielding Thermochromic properties

A novel transcription factor FnMYB4 regulates pigments metabolism of yellow leaf mutants in Fragaria nilgerrensis

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Horticultural Plant Journal 2024年第5期10卷 1134-1150页

作者： Shu jiang yi ji jingyu Yue Mingqian Wang Yumeifeng jia Li Xue jiajun Lei College of Horticulture Shenyang Agricultural UniversityShenyangLiaoning 110866China

The strawberry species Fragaria nilgerrensis Schlechtendal ex ***,renowned for its distinctive white,fragrant peach-like fruits and strong disease resistance,is an exceptional research *** a previous study,an ethyl methane sulfonate(EMS)mutant library was established for this species,resulting in various yellow leaf *** yellowing materials are not only the ideal materials for basic studies on photosynthesis mechanism,chloroplast development,and molecular regulation of various pigments,but also have important utilization value in ornamental plants *** present study focused on four distinct yellow leaf mutants:mottled yellow leaf(MO),yellow green leaf(YG),light green leaf(LG),and buddha light leaf(BU).The results revealed that the flavonoid content and carotenoid-to-chlorophyll ratio exhibited a significant increase among these mutants,while experiencing a significant decrease in chlorophyll and carotenoid contents compared to the wild type(WT).To clarify the regulatory mechanisms and network relationships underlying these mutants,the RNA-seq and weighted gene coexpression network(WGCNA)analyses were *** results showed flavonoid metabolism pathway was enriched both in MO and YG mutants,while the chlorophyll biosynthesis pathway and carotenoid degradation pathway were only enriched in MO and YG mutants,***,key structural genes and transcription factors were identified on metabolic pathways of three pigments through correlation analyses and quantitative ***,a R2R3-MYB transcription factor,FnMYB4,was confirmed to be positively correlated with flavonoid synthesis through transient overexpression,virus-induced gene silencing(VIGS),and RNA interference(RNAi),accompanying by reoccurrence and attenuation of mutant ***,dual-luciferase(LUC)and yeast one-hybrid assays confirmed the binding of FnMYB4 to the FnFLS and FnF3H promoters,indicating that FnMYB4 positively regulates flavonoid sy

关键词： Fragaria nilgerrensis Mutant Leaf yellowing RNA-seq Flavonoid MYB

Effect of multiple coulomb scattering on the beam tests of silicon pixel detectors

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Nuclear Science and Techniques 2024年第4期35卷 200-207页

作者： Lan-Kun Li Ming-yi Dong Ze Gao Liang-Cheng-Long jin Shu-Jun Zhao School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Particle Detection and Electronics(Institute of High Energy Physics CAS)Beijing 100049China University of Chinese Academy of Science Beijing 100049China University of South China Hengyang 421001China

In the research and development of new silicon pixel detectors,a collimated monoenergetic charged-particle test beam equipped with a high-resolution pixel-beam telescope is crucial for prototype verification and performance *** the beam energy is low,the effect of multiple Coulomb scattering on the measured resolution of the Device Under Test(DUT)must be considered to accurately evaluate the performance of the pixel chips and *** study aimed to investigate the effect of multiple Coulomb scattering on the measured resolution,particularly at low beam *** were conducted using Allpix^(2) to study the effects of multiple Coulomb scattering under different beam energies,material budgets,and telescope *** simulations also provided the minimum energy at which the effect of multiple Coulomb scattering could be *** with the results of a five-layer detector system tested with an electron beam at DESY,the simulation results were consistent with the beam test results,confirming the reliability of the simulations.

关键词： Silicon Pixel Detectors Beam Telescope Multiple Coulomb Scattering Spatial Resolution

Extraction of Eugenol from Essential Oils by In Situ Formation of Deep Eutectic Solvents:A Green Recyclable Process

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Journal of Analysis and Testing 2024年第1期8卷 63-73页

作者： Lingqi Shen Xiangzi jin Zhihui Zhang Yuexing yi jingyu Zhang Zuguang Li College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China Department of Chemistry Yanbian UniversityYanji 133002China Transfar Zhilian Co. Ltd.Hangzhou 311215China

Eugenol is extensively utilized in chemical *** actual production,it is mainly separated from clove essential oils(EOs)through acid-base *** this work,a simple,rapid and effective extraction process was developed for the extraction of eugenol from EOs samples by directly forming deep eutectic solvents(DESs)without using acid-base *** proposed process is designed to dissolve EOs in n-hexane and eugenol was highly selective extracted into DESs with tetrabutylammonium chloride(TBAC).Hydrogen bonds in DESs can be broken by addition of water,resulting in a separation of the two phases,thus obtaining a hydrophobic yellowish eugenol in the upper *** quaternary ammonium salt in the lower aqueous solution can be reused after *** most determining influence factors such as the structure of quaternary ammonium salt,the mole ratio of quaternary ammonium salt to eugenol and the amount of n-hexane were *** forming conditions of DESs were studied by Box-Behnken design(BBD).Experiment was carried out under the optimal conditions and good experimental result was demonstrated by the developed process,a high extraction recovery of 92.51% and the purity was about 98.50%,which verifies the excellent performance for the proposed process.

关键词： Eugenol Deep eutectic solvent Essential oils Tetrabutylammonium chloride

C_(Ar)-Br bond cleavage via cooperative EnT/NHC catalysis: mild access to indolines

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Science China Chemistry 2024年第3期67卷 922-927页

作者： yi-Xiong Dong Cao-Bo Li Ming-Lei jin Zhong-Hua Gao Song Ye Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The cooperative visible-light mediated and NHC-catalyzed dearomative arylation-acylation of N-(2-bromobenzoyl)indoles with aldehydes was developed, affording the corresponding highly functionalized polycyclic indolines in moderate to good yields with exclusive diastereoselectivities. Mechanism investigations support the activation of CAr-Br bond via visible-light mediated energy transfer(EnT) and the following single-electron-transfer(SET) with Breslow intermediate under NHC catalysis to give key aryl radical and ketyl radical. This protocol demonstrates the cleavage of CAr-Br bond under mild cooperative EnT/NHC catalysis.

关键词： energy transfer N-heterocyclic carbenes photocatalysis aryl radicals indolines