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Toward high performance microwave absorber by implanting La_(0.8)CoO_(3)nanoparticles on rGO

Journal of Materials Science & Technology 2024年第7期174卷 176-187页

作者： Li Chang Yu-Ze Wang Xin-Ci zhang Lin Li hua-zhang Zhai Mao-Sheng Cao Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics&Electronic EngineeringHarbin Normal UniversityHarbin 150025China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

The advent of“intelligent era”brings our life more convenience,but the electromagnetic radiation sur-rounding us not only greatly threatens human health,also makes information leakage and hidden trouble to national defense ***,it is very urgent to develop novel electromagnetic wave absorption materials with lightweight,strong absorption,tunable absorption frequency and broad band ***,a novel electromagnetic wave absorber is obtained by constructing La_(0.8)CoO_(3)-rGO nanocompos-ite,where La_(0.8)CoO_(3)nanoparticles are anchored on graphene nanosheets by the electrostatic interaction between GO and La_(0.8)CoO_(3).The effect of hybridization ratio of La_(0.8)CoO_(3)and rGO on microwave ab-sorption properties is carefully *** optimal reflection loss of La_(0.8)CoO_(3)-rGO nanocomposite can reach-62.34 dB with the maximum effective bandwidth of 6.08 GHz,presenting 48.78%and 245.45%increment compared to bare La_(0.8)CoO_(3)nanoparticles,*** effective absorption bandwidth covers a broad electromagnetic wave absorption band from Ku band to the C band by tailoring thickness of the absorbers from 2.4 mm to 4.4 *** fascinating electromagnetic wave absorption performance is attributed to the synergy effect of La_(0.8)CoO_(3)and rGO,which integrates magnetic and dielectric loss caused by resonance,conductance,relaxation,and scattering *** result confirms that La_(0.8)CoO_(3)-rGO nanocomposite is potential candidates toward high-efficiency microwave absorbers and provides a valuable pathway for designing high-performance microwave attenuation materials in the future.

关键词： Perovskite La_(0.8)CoO_(3)nanoparticles Graphene Nanocomposite Microwave absorbing Broad band absorption

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Understanding the Activity Performance of Comets 38P/Stephan-Oterma,64P/Swift-Gehrels and C/2017 M4(ATLAS)through Broadband Photometric Observations

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Research in Astronomy and Astrophysics 2024年第8期24卷 147-156页

作者： Xuan zhang jin-Zhong Liu Le-Tian Wang Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China

In this work,we report observations of three comets:38P/Stephan-Oterma,64P/Swift-Gehrels,and C/2017 M4(ATLAS),conducted with the Nanshan one-meter wide-field telescope in 2018 August and November,and *** extracted morphological features through image enhancement techniques and calculated the dust activity parameter,Afρ,along with dust mass loss rates and coma color indices using broadband photometric *** morphological analysis uncovered a spectrum of dust characteristics among the observed comets,ranging from a significant twisted structure in comet 38P/Stephan-Oterma’s coma to the regular coma envelope surrounding comet 64P/*** Afρvalues varied between 148.8±0.3 cm for 64P/Swift-Gehrels and1118.5±6.2 cm for C/2017 M4(ATLAS)(measured within a reference aperture radius ofρ=6″),indicating a range from moderate to high activity *** mass loss rates were estimated from 328.1 kg s^(-1)for comet 64P/Swift-Gehrels to 1395.5 kg s^(-1)for comet C/2017 M4(ATLAS).The color indices of comets 38P/Stephan-Oterma and C/2017 M4(ATLAS)closely resemble the average colors of active short-period comets and active longperiod comets,*** contrast,64P/Swift-Gehrels exhibits a significantly bluer hue than typical Jupiter family comets.

关键词： comets general-comets individual(38P/Stephan-Oterma,64P/Swift-Gehrels,C/2017 M4(ATLAS))-techniques photometric

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Static recrystallization behaviors and mechanisms of 7Mo super-austenitic stainless steel with undissolved sigma precipitates during double-stage hot deformation

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Journal of Iron and Steel Research International 2024年第2期31卷 475-487页

作者： Shi-guang Xu jin-shan He Run-ze zhang Fu-cheng zhang Xi-tao Wang Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing100083China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao066004HebeiChina Shandong Provincial Key Laboratory for High Strength Lightweight Metallic Materials Advanced Materials InstituteQilu University of Technology(Shandong Academy of Science)Jinan250353ShandongChina

Static recrystallization(SRX)behaviors and corresponding recrystallization mechanisms of 7Mo super-austenitic stainless steel were studied under different deformation *** order of influence of deformation parameters on static recrystallization behaviors,from high to low,is followed by temperature,first-stage strain and strain ***,the effect of holding time on static recrystallization behaviors is significantly controlled by *** addition,with the increase in temperature from 1000 to 1200°C,the static recrystallization mechanism evolves from discontinuous static recrystallization and continuous static recrystallization(cSRX)to metadynamic recrystallization and cSRX,and finally to *** cSRX exists at all *** is because high stacking fault energy(56 mJ m−2)promotes the movement of dislocations,making the deformation mechanism of this steel is dominated by planar slip of *** undissolved sigma precipitates promote static recrystallization through particle-stimulated ***,small strain-induced precipitates at grain boundaries hinder the nucleation of conventional SRX and the growth of recrystallized grains,while the hindering effect decreases with the increase in temperature.

关键词： 7Mo super-austenitic stainless steel Double-stage hot deformation Conventional static recrystallization Metadynamic recrystallization Strain-induced precipitation

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A Finite-Time Convergent Analysis of Continuous Action Iterated Dilemma

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 563-565页

作者： Zhen Wang Xiaoyue jin Tao zhang Dengxiu Yu Northwestern Polytechnical University

Dear Editor,In this letter, a finite-time convergent analysis of continuous action iterated dilemma(CAID) is proposed. In traditional evolutionary game theory, the strategy of the player is binary(cooperation or defec... 详细信息

关键词： lemma letter convergent

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Thickening progression mechanism of silica fume-oil well cement composite system at high temperatures

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Petroleum Science 2024年第4期21卷 2793-2805页

作者： Hang zhang Miao-Miao Hu Peng-Peng Li Guo-Qing Liu Qing-Lu Chang Jie Cao Ming Liu Wen-hua Xu Xiu-Jian Xia jin-Tang Guo School of Chemical Engineering and Technology Tianjin University Zhejiang Institute of Tianjin University Haihe Laboratory of Sustainable Chemical Transformations CNPC Engineering Technology R&D Company Limited

This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C) in order to provide a theoretical guidance for the rational application of silica fume in the cementing engineering. Results showed that silica fume seldom affected the thickening progression of oil well cement slurry at 110-120.C, but when temperature reached above130.C, it would aggravate the bulging degree of thickening curves and significantly extend the thickening time, meanwhile causing the abnormal “temperature-based thickening time reversal” and“dosage-based thickening time reversal” phenomena in the range of 130-160.C and 170-180.C respectively. At 130-160.C, the thickening time of oil well cement slurry was mainly associated with the generation rate of calcium hydroxide(CH) crystal. The introduced silica fume would be attracted to the cement minerals' surface that were hydrating to produce CH and agglomerate together to form an“adsorptive barrier” to hinder further hydration of the inner cement minerals. This “adsorptive barrier”effect strengthened with the rising temperature which extended the thickening time and caused the occurrence of the “temperature-based thickening time reversal” phenomenon. At 170-180.C, the pozzolanic activity of silica fume significantly enhanced and considerable amount of C-S-H was generated, thus the “temperature-based thickening time reversal” vanished and the “dosage-based thickening time reversal” was presented.

关键词： Silica fume Oil well cement Thickening time reversal Pozzolanic reaction Adsorptive barrier CH and C−S−H

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Magnetism of NaYbS_(2):From finite temperatures to ground state

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Science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 92-104页

作者： Weizhen Zhuo Zheng zhang Mingtai Xie Anmin zhang Jianting Ji Feng jin Qingming zhang School of Physical Science and Technology Lanzhou UniversityLanzhou 730000China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Rare-earth chalcogenide compounds ARECh_(2)(A=alkali or monovalent metal,RE=rare earth,Ch=O,S,Se,Te)are a large family of quantum spin liquid(QSL)candidate ***2is a representative member of the *** key issues on NaYbS_(2),particularly how to determine the highly anisotropic spin Hamiltonian and describe the magnetism at finite temperatures and the ground state,remain to be *** this paper,we conducted an in-depth and comprehensive study on the magnetism of NaYbS_(2) from finite temperatures to the ground ***,we successfully detected three crystalline electric field(CEF)excitation energy levels using low-temperature Raman scattering *** them with the CEF theory and magnetization data,we worked out the CEF parameters,CEF energy levels,and CEF *** further determined a characteristic temperature of~40 K,above which the magnetism is dominated by CEF excitations while below which the spinexchange interactions play a main *** characteristic temperature has been confirmed by the temperature-dependent electron spin resonance(ESR)***-temperature ESR experiments on the dilute magnetic doped crystal of NaYb_(0.1)Lu_(0.9)S_(2) further helped us to determine the accurate ***,we quantitatively obtained the spin-exchange interactions in the spin Hamiltonian by consistently simulating the magnetization and specific heat ***,the above studies allow us to explore the ground state magnetism of NaYbS_(2) by using the density matrix renormalization *** combined numerical calculations and experimental results to demonstrate that the ground state of NaYbS_(2) is a Dirac-like QSL.

关键词： rare-earth chalcogenide anisotropic spin Hamiltonian quantum spin liquid

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SDCC: software-defined collective communication for distributed training

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Science China(Information Sciences) 2024年第9期67卷 105-125页

作者： Xin jin Zhen zhang Yunshan JIA Yun MA Xuanzhe LIU School of Computer Science Peking University Department of Computer Science and Technology Johns Hopkins University

Communication is crucial to the performance of distributed training. Today's solutions tightly couple the control and data planes and lack flexibility, generality, and performance. In this study, we present SDCC, a software-defined collective communication framework for distributed training. SDCC is based on the principle of modern systems design to effectively decouple the control plane from the data *** abstracts the operations for collective communication in distributed training with dataflow operations and unifies computing and communication with a single dataflow graph. The abstraction, together with the unification, is powerful: it enables users to easily express new and existing collective communication algorithms and optimizations, simplifies the integration with different computing engines(e.g., Py Torch and Tensor Flow) and network transports(e.g., Linux TCP and kernel bypass), and allows the system to improve performance by exploiting parallelism exposed by the dataflow graph. We further demonstrate the benefits of SDCC in four use cases.

关键词： machine learning systems distributed training deep learning collective communication software-defined networking

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Fe-Induced Electronic Transfer and Structural Evolution of Lotus Pod-Like CoNiFePx@P,N-C Heterostructure for Sustainable Oxygen Evolution

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Energy & Environmental Materials 2024年第3期7卷 186-193页

作者： Xiaojun Zeng Qingqing zhang Chulong jin Hui huang Yanfeng Gao Advanced Ceramic Materials Research Institute School of Materials Science and EngineeringJingdezhen Ceramic University Singapore Institute of Technology School of Materials Science and Engineering Shanghai University

Transition metal phosphides with metallic properties are a promising candidate for electrocatalytic water oxidation,and developing highly active and stable metal phosphide-based oxygen evolution reaction catalysts is still ***,we present a facile ion exchange and phosphating processes to transform intestine-like CoNiPx@P,N-C into lotus pod-like CoNiFePx@P,N-C heterostructure in which numerous P,N-codoped carboncoated CoNiFePxnanoparticles tightly anchors on the 2D carbon ***,the as-prepared CoNiFePx@P,N-C enables a core-shell structure,high specific surface area,and hierarchical pore structure,which present abundant heterointerfaces and fully exposed active ***,the incorporation of Fe can also induce electron transfer in CoNiPx@P,IM-C,thereby promoting the oxygen evolution ***,CoNiFePx@P,IM-C delivers a low overpotential of 278 mV （vs RHE） at a current density of10 mA cm-1and inherits excellent long-term stability with no observable current density decay after 30 h of chronoamperometry *** work not only highlights heteroatom induction to tune the electronic structure but also provides a facile approach for developing advanced and stable oxygen evolution reaction electrocatalysts with abundant heterointerfaces.

关键词： electronic transfer Fe exchange multi-metal phosphides OER electrocatalysts structural evolution

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DBT-PDP:Provable data possession with outsourced data batch transfer based on blockchain

High-Confidence Computing

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High-Confidence Computing 2024年第2期4卷 62-72页

作者： Chengming Yi hua zhang Weiming Sun Jun Ding State key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China Zhe Jiang Computer Network Emergency Response Technical Team Hangzhou 310052China

In the scenario of large-scale data ownership transactions,existing data integrity auditing schemes are faced with security risks from malicious third-party auditors and are inefficient in both calculation and communication,which greatly affects their *** paper proposes a data integrity audit scheme based on blockchain where data ownership can be traded in batches.A data tag structure which supports data ownership batch transaction is adopted in our *** update process of data tag does not involve the unique information of each data,so that any user can complete ownership transactions of multiple data in a single transaction through a single transaction auxiliary *** the same time,smart contract is introduced into our scheme to perform data integrity audit belongs to third-party auditors,therefore our scheme can free from potential security risks of malicious third-party *** analysis shows that our scheme is proved to be safe under the stochastic prediction model and k-CEIDH *** with similar schemes,the experiment shows that communication overhead and computing time of data ownership transaction in our scheme is ***,the communication overhead and computing time of our scheme is similar to that of similar schemes in data integrity audit.

关键词： Data integrity Cloud outsourcing audit Data ownership batch transaction Blockchain Smart contract

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Expression of COX-2 and VEGF-C in patients with squamous cell carcinoma of tongue and its correlation with lymph node metastases

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中国口腔颌面外科杂志 2008年第B5期6卷 132-133页

作者： Wei Zhong Li Yan Qing Ding Zu Guo Li jin hua zhang Department of Stomatology Southern Medical University Guangzhou 510515 Department of Pathology Nanfang Hospital Southern Medical University Guangzhou 510515 China

Purpose: To evaluate the coexpression of COX-2, VEGF-C and CD34 in human squamous cell carcinoma of tongue (SCCT) and to determine their relationships and correlations with lymph node metastasis。Methods: Tissue samples of primary tumors and metastatic carcinoma in lymph nodes from 46 patients undergoing surgical resections for SCCT were immunohistochemically examined。Results: The over-expression of COX-2 and VEGF-C in the primary tumor was 82.61% and 73.91%。The result showed a positive correlation between the expression level of COX-2 and VEGF-C in carcinoma tissues of tongue。Their correlation coefficient (rs) was 0.874 (P=0.000)。Conclusions: The coexpression of COX-2 and VEGF-C had close relationship to biological behaviors in human tongue squamous cell carcinoma。It may be an important marker in evaluating the prognosis, metastasis and invasion in HTSCC。However, the mechanism of both proteins in carcinogenesis in HTSCC needs further investigation。

关键词：舌肿瘤淋巴鳞状细胞癌治疗方法

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