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Poly(o-xylylene)s via Cobalt-Catalyzed Reductive Polymerization

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Chinese Journal of Chemistry 2020年第9期38卷 952-958页

作者： si Chen Yanchuan Zhao Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryChinese Academy of Sciences345 Ling-Ling RoadShanghai 200032China Key Laboratory of Energy Regulation Materials Shanghai Institute of Organic ChemistryChinese Academy of Sciences345 Ling-Ling RoadShanghai 200032China

Summary of main observation and conclusion Poly(p-xylylene)s(PPX)have found wide applications in various fields owing to their chemical robustness,low gas permeability and excellent dielectric *** a structural isomer of PPX,poly(o-xylylene)s(POX),possessing a distinct main-chain connectivity,are excellent candidates to pursue ***;however,the investigation of POX is hampered by *** of efficient synthetic ***,we report a straightforward way to access POXs through a cobalt-catalyzed reductive *** method not only allows the direct preparation of electronically unmodified POXs,but also enables the copolymerization between o-xylylene dibromides bearing different aryl or benzylic *** glass transition temperatures of the copolymers can be finely tuned by varying the ratio between *** obtained POXs are solvent processible and amenable for thin-film *** aryl bromide moiety remains untouched during the polymerization,post-polymerization functionalization is easily achieved through Suzuki-Miyaura coupling *** chemistry also enables the copolymerization of xylylene dibromide regioisomers,thereby leading to diversified non-conjugated polymers,whose backbones are rich in arylene ***,the use of the polymerization strategy to synthesize structurally novel porous polymers is demonstrated.

关键词： properties. reaction. polymerization

P-FEMOL ANALYsiS OF PLATE BENDING PROBLEMS

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Acta Mechanica Solida sinica 1994年第1期7卷 39-45页

作者： si, Yuan Tsinghua Univ Beijing China

In this paper, the p- version of the finite element method of lines (FEMOL) for the analysis of the Mindlin-Reissner plate bending problems is presented and a class of p-FEMOL elements with polynomial degrees as high as nine is developed. Numerical examples given in this paper show tremendous performance of the present method: namely, rapid convergence rate, high accuracy for both displacements and stress resultants, removal of shear-locking trouble, capability of dealing with difficult problems such as the boundary layer behavior near a free edge and stress concentration around a hole.

关键词： Bending (deformation) Boundary layers Convergence of numerical methods Differential equations Finite element method Geometry Mathematical models Performance Plates (structural components) Polynomials Stresses

略论新时代高校网络意识形态安全的风险挑战与应对策略

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湖北科技学院学报 2025年第1期45卷 73-79页

作者：田贵华沈思雨武汉大学马克思主义学院湖北武汉430072

高校意识形态安全作为国家安全的重要方面,对培养社会主义事业合格建设者和可靠接班人,确保高校坚持社会主义办学方向尤为重要。新时代高校网络意识形态安全面临着西方敌对势力渗透、错误社会思潮干扰、信息传播圈层化阻隔等诸多挑战。... 详细信息

高校意识形态安全作为国家安全的重要方面,对培养社会主义事业合格建设者和可靠接班人,确保高校坚持社会主义办学方向尤为重要。新时代高校网络意识形态安全面临着西方敌对势力渗透、错误社会思潮干扰、信息传播圈层化阻隔等诸多挑战。为有效应对这些风险挑战,高校亟需强化价值引领,提高抵御风险能力;建强工作队伍,构建协同育人格局;加强网络管理,营造清朗网络环境;创新方式方法,提升青年网络安全素养。

关键词：新时代高校网络意识形态安全挑战对策

PRI modulation recognition and sequence search under small sample prerequisite

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Journal of Systems Engineering and Electronics 2023年第3期34卷 706-713页

作者： ZHANG Chunjie LIU Yuchen si Weijian College of Information and Communication Engineering Harbin Engineering UniversityHarbin 150001China Key Laboratory of Advanced Marine Communication and Information Technology Ministry of Industry and Information TechnologyHarbin Engineering UniversityHarbin 150001China

Pulse repetition interval(PRI)modulation recognition and pulse sequence search are significant for effective electronic support *** modern electromagnetic environments,different types of inter-pulse slide radars are highly *** are few available training samples in practical situations,which leads to a low recognition accuracy and poor search effect of the pulse *** this paper,an approach based on bi-directional long short-term memory(BiLSTM)networks and the temporal correlation algorithm for PRI modulation recognition and sequence search under the small sample prerequisite is *** simulation results demonstrate that the proposed algorithm can recognize unilinear,bilinear,sawtooth,and sinusoidal PRI modulation types with 91.43% accuracy and complete the pulse sequence search with 30% missing pulses and 50% spurious pulses under the small sample prerequisite.

关键词： inter-pulse slide pulse repetition interval(PRI)modulation type bi-directional long short-term memory(BiLSTM)network sequence search

Properties of collective flow and pion production in intermediate-energy heavy-ion collisions with a relativistic quantum molecular dynamics model

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Nuclear Science and Techniques 2024年第1期35卷 155-169页

作者： si-Na Wei Zhao-Qing Feng School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

The relativistic mean-field approach was implemented in the Lanzhou quantum molecular dynamics transport model(***). Using the ***, the properties of collective flow and pion production were investigated systematically for nuclear reactions with various isospin asymmetries. The directed and elliptic flows of the *** are able to describe the experimental data of STAR Collaboration. The directed flow difference between free neutrons and protons was associated with the stiffness of the symmetry energy, that is, a softer symmetry energy led to a larger flow difference. For various collision energies, the ratio between the π^(-) and π^(+) yields increased with a decrease in the slope parameter of the symmetry energy. When the collision energy was 270 MeV/nucleon, the single ratio of the pion transverse momentum spectra also increased with decreasing slope parameter of the symmetry energy in both nearly symmetric and neutron-rich ***, it is difficult to constrain the stiffness of the symmetry energy with the double ratio because of the lack of threshold energy correction on the pion production.

关键词： Heavy-ion collision Collective flow Pion production Symmetry energy Relativistic mean field

Unraveling Iterative Control Structures from Business Processes

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Journal of Computer Science & Technology 2021年第1期36卷 158-190页

作者： Yain-Whar si Weng-Hong Yung Department of Computer and Information Science University of MacaoMacaoChina

Iterative control structures allow the repeated execution of tasks,activities or sub-processes according to the given conditions in a process *** control structures can significantly increase the risk of triggering temporal exceptions since activities within the scope of these control structures could be repeatedly executed until a predefined condition is *** this paper,we propose two approaches to unravel iterative control structures from process *** first approach unravels loops based on zero-one *** second approach unravels loops based on branching probabilities assigned at split *** proposed methods can be used to unfold structured loops,nested loops and crossing *** the unfolded model does not contain any iterative control structures,it can be used for further analysis by process designers during the modeling *** proposed methods are implemented based on workflow graphs,and therefore they are compatible with modeling languages such as Business Process Modelling Notation(BPMN).In the experiments,the execution behavior of unfolded process models is compared against the original models based on the concept of *** results reveal that runs generated from the original models can be correctly executed in the unfolded BPMN models that do not contain any loops.

关键词： business process management iterative control structure unravelling zero-one principle branching probability

Stable 4.5 V LiCoO_(2)cathode material enabled by surface manganese oxides nanoshell

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Nano Research 2023年第2期16卷 2480-2485页

作者： Jun Wang si-Dong Zhang si-Jie Guo si-Qi Lu Yan-Song Xu Jin-Yang Li An-Min Cao Li-Jun Wan CAS Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular Sciences Institute of ChemistryChinese Academy of Sciences(ICCAS)Beijing 100190China University of Chinese Academy of Sciences(UCAS) Beijing 100049China

Charging the LiCoO_(2)(LCO)cathode to a higher voltage,for example 4.5 V compared to the commonly used 4.2 V,is now intensively pursued so as to achieve a higher specific ***,it suffers severe surface structural degradation and detrimental interfacial side reactions between cathode and electrolyte,which lead to the fast capacity fading during long-term ***,a surface coating strategy was developed for the protection of 4.5 V LCO by constructing a manganese oxides(MOs)nanoshell around LCO particles,which was achieved through a solution-based coating process with success in controlling the growth kinetics of the coating *** found that the introduction of the MOs nanoshell is highly effective in alleviating the organic electrolyte decomposition at the cathode surface,thus ensuring a much more stable LiF-rich cathode-electrolyte interface and an obvious lower interfacial resistance during electrochemical ***,this protection layer can effectively improve the structural stability of the cathode by hindering the cracks formation and structural degradation of LCO ***,the MOs modified LCO exhibited excellent rate performance and a high discharge capacity retention of 81.5%after 100 cycles at 1 C compared with the untreated LCO(55.2%),as well as the improved thermal stability and cyclability at the elevated *** is expected that this discovery and fundamental understanding of the surface chemistry regulation strategy provide promising insights into improving the reversibility and stability of LCO cathode at the cut-off voltage of 4.5 V.

关键词： lithium-ion battery 4.5 V LiCoO_(2) manganese oxides surface coating interfacial stability regulation

Superconducting X-ray detectors

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Science China(Information Sciences) 2020年第8期63卷 91-109页

作者： Can YANG Mengting si Lixing YOU State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology (SIMIT)Chinese Academy of Sciences CAS Center for Excellence in Superconducting Electronics (CENSE) Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Zhejiang Photon Technology Co.Ltd. Guigu Science Park

Owing to their high sensitivity and low noise, superconducting detectors are used for photon detection from microwave to high-energy particles. X-ray detection plays an important role in materials analysis, astronomy, and medical radiography, which require high efficiency as well as high energy resolution. However, traditional semiconducting detectors cannot fulfill these requirements. In this article, we review superconducting quantum detectors for X-ray detection, including transition-edge sensor(TES), superconducting tunneling junctions(STJs), kinetic inductance detectors(KIDs) and superconducting nanowire single-photon detectors(SNSPDs), and introduce the physical structures, working mechanisms, and device behaviors of these detectors. We also review their performances regarding X-ray detection and analyze their respective characteristics. According to recent progress and the requirements of various applications, possible improvement of superconducting detectors for X-rays are discussed.

关键词： superconducting X-ray detectors transition-edge sensors superconducting tunneling junctions kinetic inductance detectors superconducting nanowire single-photon detector

LaO_(x)(OH)_(y) supported platinum catalysts for CO oxidation:Deactivation by formation of lanthanum carbonate

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Journal of Rare Earths 2021年第3期39卷 297-304,I0003页

作者： Luozhen Jiang Junxiang Chen Rui si Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201204China Shanghai Synchrotron Radiation Facility Zhangjiang LaboratoryShanghai 201204China Division of China TILON Group Technology LimitedShanghai 200090China University of Chinese Academy of Sciences Beijing 100049China

Platinum catalyst for CO oxidation has been studied for decades,due to its high activity and good *** this work,we prepared three different lantha num oxide or hydroxide supports(LaO_(x)(OH)_(y)),and deposited platinum(Pt) with 0.5 at% via an impregnation approach to synthesize Pt/LaO_(x)(OH)_(y) ***,we find that these catalysts perform a poor stability for the CO oxidation *** fresh and used samples were comprehensively characterized by multiple techniques including power X-ray diffraction(XRD),X-ray absorption fine structure(XAFS),transmission electron microscopy(TEM),temperature-programmed reduction by carbon monoxide(CO-TPR) and thermogravimetric analysis(TGA),to demonstrate that the oxidized platinum atoms or clusters,without any component of Pt-Pt metallic bond,are highly dispersed on the surface of LaO_(x)(OH)_(y).Furthermore,the as-formed lanthanum carbonate(La_(2)O_(2)CO_(3)) during the exposure to ambient circumstances or in the reaction atmosphere of CO+O_(2),severely impair the reactivity of Pt/LaO_(x)(OH)_(y).On the basis of the obtained experimental results,we have drawn a conclusion that the oxidized P_(t)O_(x) atoms or PtxOy clusters are the active species for CO oxidation,while the formation of lanthanum carbonate is the origin of deactivation on reactivity.

关键词： Platinum catalyst Lanthanum oxide Lanthanum hydroxide CO oxidation Structure-activity relationship Rare earths