检索结果-南通市图书馆

science China Chemistry 2024年第11期67卷 3739-3748页

作者： Wenjie Wang Hui Ding Minghao Wang Han Cheng Xiang Shi Lin Wang Chun Wang Wangsheng Chu Yi Xie Changzheng Wu National Synchrotron Radiation Laboratory University of Science and Technology of China School of Chemistry and materials science CAS Center for Excellence in Nanoscience University of Science & Technology of China Zhejiang Institute of Photoelectronics Institute of Energy Hefei Comprehensive National Science Center

The establishment of reactive oxygen species(ROS) elimination sites in iron-nitrogen-carbon(Fe-N-C) electrocatalysts to achieve durable proton-exchange membrane fuel cells(PEMFCs) performance has attracted broad interest. However, realizing ROS removal efficiency and oxygen reduction reaction(ORR) activity within a single system represents a significant challenge to date. Herein, we demonstrate uniform ROS elimination sites and ORR centers through an electrochemical reconstruction method on the parallel sites of Fe@Ce NC electrocatalyst for durable PEMFC. During the reconstruction process, the Fe sites can retain their original configuration. Meanwhile, the pristine Ce clusters will evolve into more efficient, highly dispersed ***, the reconstructed Fe and Ce sites exhibit favorable energy barriers for the ORR and ROS elimination pathways,respectively, thereby maintaining ORR activity and achieving high ROS tolerance. Consequently, the PEMFC assembled with our catalyst shows only a 2% decay in power density after the accelerated durability test. We anticipate that this parallel structure design will provide new insight into the development of more durable electrocatalysts for PEMFCs.

关键词： parallel reaction pathways sites reconstruction oxygen reduction reaction radical elimination fuel cells

Field induced Chern insulating states in twisted monolayer–bilayer graphene

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第6期33卷 69-73页

作者：王政文韩英卓 Kenji Watanabe Takashi Taniguchi 姜宇航毛金海 School of Physical science and CAS center for excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100049China College of materials science and Optoelectronic technology Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China Advanced materials Laboratory National Institute for Materials ScienceTsukuba 305-0044Japan

Unraveling the mechanism underlying topological phases, notably the Chern insulators(Ch Is) in strong correlated systems at the microscopy scale, has captivated significant research interest. Nonetheless, Ch Is harboring topological information have not always manifested themselves, owing to the constraints imposed by displacement fields in certain experimental configurations. In this study, we employ density-tuned scanning tunneling microscopy(DT-STM) to investigate the Ch Is in twisted monolayer–bilayer graphene(t MBG). At zero magnetic field, we observe correlated metallic *** under a magnetic field, a metal–insulator transition happens and an integer Ch I is formed emanating from the filling index s = 3 with a Chern number C = 1. Our results underscore the pivotal role of magnetic fields as a powerful probe for elucidating topological phases in twisted Van der Waals heterostructures.

关键词： Chern insulators strong correlation effects two-dimensional van der Waals heterostructure density-tuned scanning tunneling microscopy(DT-STM)

Two-stage aging treatment to accelerate aging kinetics without impairing strength in B_4C/7A04Al composite

在线全文

学校读者我要写书评

暂无评论

science China(Technological sciences) 2024年第8期67卷 2485-2492页

作者： CHEN YunTao MA GuoNan ZHU ShiZe WANG Dong XIAO BoLv MA ZongYi Shi-Changxu Innovation center for Advanced materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of materials science and Engineering University of Science and Technology of ChinaShenyang 110016China Centre of excellence for Advanced materials Dongguan 523808China

Aging treatments are the key process to obtain satisfactory strength for 7xxxAl alloys and their composites. However, traditional single-stage(SS) aging is time-consuming to reach a peak strength condition. In this study, an efficient 120℃ + 160℃ two-stage(TS) aging treatment was proposed on a B_4C/7A04Al composite fabricated via powder metallurgy(PM) technology, which could acquire similar peak-aging strength but only took about 15% of the time compared to traditional 120℃ SS aging. The evolution of precipitation during the TS aging was investigated, as well as those of the 7A04Al alloys for comparison. In the second stage aging process, the higher aging temperature accelerated the nucleation of η′ phases inside the grains and thus increased the density of precipitates. Moreover, the short aging time limited the coarsening of precipitates and the broadening of precipitatefree zones. The above factors were beneficial for quickly obtaining satisfactory precipitation strengthening effects. The B_4C/7A04Al composite exhibited slower aging kinetics than the 7A04Al alloy in the TS aging. Mg elements consumption by the chemical reaction between B impurities introduced by B_4C particles and the Al matrix was considered to potentially retard the aging kinetics of the B_4C/7A04Al composite. Nevertheless, the precipitation sequence was not affected.

关键词： aluminum matrix composites aging treatment powder metallurgy mechanical properties precipitation

Properties of Ultra-low Thermal Expansion LAS Transparent glass-ceramics Prepared by Spodumene

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of technology(materials science) 2024年第3期39卷 541-550页

作者：何峰何子君 ZHOU Zhiqiang TIAN Yingliang ZHAO Zhiyong School of materials science and Engineering Beijing University of TechnologyBeijing 100124China Department of Functional Material Research Central Iron and Steel Research InstituteBeijing 100081China School of materials science and Engineering Wuhan University of TechnologyWuhan 430070China National Engineering Research center of FPD glass technology Xianyang 712000China

The glass-ceramics were prepared with the spodumene mineral as the main raw material,and the effects of ZrO_(2)replacing TiO_(2)on the samples were systematically *** results show that the substitution of ZrO_(2)for TiO_(2)is not conductive to precipitate𝛽β-quartz solid solution phase,but can improve the transparency and flexural strength of *** the glass-ceramic with the highest visible light transmittance(87%)and flexural strength(231.80 MPa)exhibits an ultra-low thermal expansion of-0.028×10^(-7)K^(-1)in the region of 30-700℃.

关键词： ultra-low thermal expansion LAS transparent glass-ceramics substitution of ZrO_(2)for TiO_(2) spodumene mineral

Screened peptides from one-bead one-compound technique extend half-life of peptide drugs in circulation through binding to albumin

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第3期35卷 384-388页

作者： Yi-Jing Li Lingze Zhang Ming-Hao Pang Pei-Pei Yang Lu-Ming Guo Kuo Zhang Da-Yong Hou Lei Wang Hao Wang Hui Cao State Key Laboratory for Advanced Metals and materials School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China CAS center for excellence in Nanoscience CAS Key Laboratory for Biomedical Effects of Nanomaterials NanosafetyNational Center for Nanoscience and Technology(NCNST)Beijing 100190China

Peptide drugs are known for their high biological ***,compared with small molecule drugs,peptide drugs are easily oxidized and hydrolyzed as well as short in ***,inspired by the long circulation of albumin in blood,we screened albumin binding peptides(ABPs)from a one-bead one-compound(OBOC)peptide library to increase the half-life of peptide *** displaying random peptides were screened using fluorescent labeled human serum *** beads with specific binding to albumin were isolated for *** selected ABPs can effectively bind to albumin,thus possessing the long circulation of *** dissociation constant(K_(D))of ABPs to albumin is up to 1×10^(-8)mol/*** one of ABPs(ABP2)was coupled to triptorelin,the circulation half-life of triptorelin in mice was significantly prolonged to 263.50 h much longer than that of triptorelin alone(179.07 h).In addition,the combination therapy using ABP-conjugated triptorelin and doxorubicin(DOX)can effectively inhibit the proliferation of tumor cells in *** OBOC screening strategy and resulting ABPs showed great potential for enhancing the delivery efficiency of peptide drugs.

关键词： One-bead one-compound Combinatorial library Albumin binding Drug delivery Triptorelin

Surface vitrification of carbon by laser treatment: Insights of glass formation from molecular dynamics

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2024年第6期13卷 729-735页

作者： Yanhui Zhang Haifeng Yu Yongying Jia Zhisheng Zhao Li-Min Wang Riping Liu center for Advanced Structural materials State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao 066004China

Microstructural modification of carbon materials,such as carbon fibers(Cf)and pyrolytically deposited carbon,is important for engineering ***,the regulation of these materials is not an effortless *** understand the impacts of thermal spikes from pulsed laser processing on the structural adaptation of amorphous carbon(a-C),we performed melt quenching by molecular dynamics(MD)*** results confirm that the vitrification behavior of carbon can be tuned by adjusting the cooling rate(R),which is controlled by the thermal spikes of laser ***,we set up a two-step way to locate the critical cooling rate(R_(c))of monoatomic carbon,which is refined by the sharp change in the environmental similarity *** this novel technique,we demonstrate that the ordering degree and the local atomic motif can be largely modified by going across a bar of 100 K/ps,which is extracted as the critical cooling rate to ensure the complete amorphization of *** approach provides a criterion for both experimentally processing and theoretically simulating a-C ***,this work provides guidelines on how to tune the amorphous carbon structures of engineering materials and provides an outlook for the wonderland of amorphous carbon materials.

关键词： molecular dynamics(MD) structural order carbon fibers(Cf) vitrification critical cooling rate(R_(c))

Designed imidazole-based supramolecular catalysts for accelerating oxidation/hydrolysis cascade reactions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第6期17卷 4916-4923页

作者： Yuanxi Liu Wenjie Xu Shichao Xu Haifeng Wu Baoli Zhang Li Song Zhen-Gang Wang State Key Laboratory of Organic-Inorganic Composites Key Lab of Biomedical Materials of Natural Macromolecules(Ministry of Education)Beijing Laboratory of Biomedical MaterialsCollege of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China National Synchrotron Radiation Laboratory CAS Center for Excellence in NanoscienceUniversity of Science and Technology of ChinaHefei 230029China

Reconstructing enzymatic active sites presents a significant challenge due to the intricacies involved in achieving enzyme-like scaffold folding and spatial arrangement of essential functional *** is also a growing interest in building biocatalytic networks,wherein multiple enzymatic active sites are localized within a single artificial system,allowing for cascaded *** this work,we report the self-assembly of imidazole or its derivatives with fluorenylmethyloxycarbonyl-modified histidine and Cu2+to fabricate a supramolecular catalyst,which possesses catechol oxidase-like dicopper center with multiple imidazole as the coordination *** electron microscopy,low-temperature X-band continuous-wave electron paramagnetic resonance,K-edge X-ray absorption spectra/the extended X-ray absorption fine structure analysis,and density functional theory modeling were used for the structural characterization of the *** phenol derivatives and the dissolved oxygen were used as the substrates,with the addition of 4-aminoantipyrine to generate a red adduct with a maximum absorbance at 510 nm,for obtaining time-dependent absorbance change curves and estimating the *** results reveal that the addition of imidazole synergistically accelerates the oxidative activity about 10-fold and the hydrolysis activity about 14-fold than fluorenylmethyloxycarbonyl modified-histidine/Cu2+.The supramolecular nanoassembly also exhibits the ability to catalyze oxidation/hydrolysis cascade reactions,converting 2′,7′-dichlorofluorescin diacetate into 2′,7′-*** process can be regulated through the methylation of the imidazole component at various *** work may contribute to the design of advanced biomimetic catalysts,and shed light on early structural models of the active sites of the primitive copper-dependent enzymes.

关键词： enzyme mimic self-assembly supramolecular catalyst cascade reactions

Chemical vapor deposition for perovskite solar cells and modules

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第4期45卷 1-4页

作者： Zhihao Tao Yuxuan Song Baochang Wang Guoqing Tong Liming Ding School of materials science and Engineering Hefei University of TechnologyHefei 230009China center for excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Metal halide perovskites are promising materials for solar cells because of high power conversion efficiency(PCE),tun-able bandgap,high defect tolerance,long carrier diffusion length,and low-cost fabrication[1-7].The PCE for perovskite solar cells(PSCs)reaches 26.14%for single-junction cells,29.1%for perovskite/perovskite tandem cells and 33.9%for perovskite/silicon tandem cells,being comparable to that for silicon and other thin-film solar cells[8-10].Perovskite solar cells have been made by solution methods including spin-coat-ing,blade coating and printing[11,12].

关键词： perovskite blade film

Ultraviolet Photodetector based on Sr_(2)Nb_(3)O_(10) Perovskite Nanosheets

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of technology(materials science) 2024年第2期39卷 282-287页

作者：张斌斌 JIA Mengmeng LIANG Qi WU Jinsong ZHAI Junyi 李宝文 School of materials science and Engineering Wuhan University of TechnologyWuhan 430070China CAS center for excellence in Nanoscience Beijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijin 100083China State Key Laboratory of Advanced technology for materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Liquid-phase exfoliation was employed to synthesize Sr_(2)Nb_(3)O_(10) perovskite nanosheets with thicknesses down to 1.76 *** electron microscopy(TEM),atomic force microscope(AFM),X-ray photoelectron spectrometer(XPS),and other characterization techniques were used to evaluate the atomic structure and chemical composition of the exfoliated nanosheets.A UV photodetector based on individual Sr_(2)Nb_(3)O_(10) nanosheets was prepared to demonstrate the application of an ultraviolet(UV) *** UV photodetector exhibited outstanding photocurrent and responsivity with a responsivity of 3×10^(5) A·W^(-1) at 5 V bias under 280 nm illumination,a photocurrent of 60 nA,and an on/off ratio of 3×10^(2).

关键词： perovskite nanosheets liquid-phase exfoliation ultraviolet photodetector

Quantum key distribution over a mimicked dynamic-scattering channel

在线全文

学校读者我要写书评

暂无评论

science China(Information sciences) 2024年第4期67卷 323-330页

作者： Qi-Hang LU Fang-Xiang WANG Wei CHEN Hai-Yang FU Yin-Jie LU Shuang WANG De-Yong HE Zhen-Qiang YIN Guang-Can GUO Zheng-Fu HAN CAS Key Laboratory of Quantum Information University of Science and Technology of China CAS center for excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China

Free-space quantum key distribution(QKD) plays an important role in the global quantum network. However, free space channels suffer from the atmospheric turbulence and scattering effects of haze,fog, and dust, which significantly weaken the performance of QKD or even block the secure quantum ***, we prove the performance of QKD over a dynamic scattering channel can be enhanced significantly using a fast wavefront shaping technique. The system achieves on average 10-dB enhancement of quantum transmission efficiency and establishes a secure quantum link for QKD. Our work demonstrates the feasibility of QKD through free-space dynamic scattering channels and enhances the deployment capability of complex-channel QKD system.

关键词： quantum key distribution free space channel channel turbulence channel scattering wavefront shaping