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Crystallization,Mechanical,Thermal and Rheological Properties of Polypropylene Composites Reinforced by Magnesium Oxysulfate Whisker

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Chinese Journal of Polymer Science 2017年第5期35卷 659-671页

作者： Li Dang Xue-ying Nai Xin Liu dong-hai Zhu ya-ping dong 李武 Key Laboratory of Salt Lake Resources Chemistry Qinghai Institute of Salt LakesChinese Academy of Sciences Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources Qinghai Institute of Salt Lakes Chinese Academy of Sciences University of Chinese Academy of Sciences

Polypropylene （PP） composites containing magnesium oxysulfate whisker （MOSw） or lauric acid （LA） modified MOSw （LAMOSw） were prepared via melt mixing in a torque rheometer. The heterogeneous nucleating effect of LAMOSw was clearly observed in polarized light microscopy （PLM） pictures with the presence of an abundance of small spherulites. MOSw exhibited no nucleation effect and formed a few spherulites with large size. Compared with PP/MOSw composites, PP/LAMOSw exhibited better impact strength, tensile strength and nominal strain at break, ascribing to three possible reasons：（i） more β-crystal PP formed, （ii） better dispersity of LAMOSw in PP matrix and （iii） the plasticizing effect of LA. The results of dynamic mechanical thermal analysis （DMTA） indicated that brittleness of the PP matrix at low temperature was improved by the addition of LAMOSw, while the interracial interactions between MOSw and PP matrix were actually weakened by LA, as evidenced by the higher tan8 values over the entire range of test temperatures. In terms of the rheological properties of the composites, both the η＊ and G＇ at low frequencies increase with the addition of MOSw or LAMOSw, indicating that the PP matrix was transformed from liquid-like to solid-like. However, a network of whiskers did not form because no plateau was found in the G＇ at low frequencies. With low filler content, LAMOSw produced a stronger solid-like behavior than MOSw mainly due to the better dispersion of the LAMOSw in PP matrix. However, for highly-filled composites, the η＊ of PP/LAMOSw at low frequencies was smaller than that of PP/MOSw composite, since the particle- particle contact effect played a major role.

关键词： PP/MOSw composites Crystallization Thermal properties Mechanical properties Rheological properties

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Effects of Different Compatibilizing Agents on the Interfacial Adhesion Properties of Polypropylene/Magnesium Oxysulfate Whisker Composites

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Chinese Journal of Polymer Science 2017年第9期35卷 1143-1155页

作者： Li Dang Xue-ying Nai Xin Liu dong-hai Zhu ya-ping dong 李武 Key Laboratory of Salt Lake Resources Chemistry Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining 810008 China Key Laboratory of Comprehensive andHighly Efficient Utilization of Salt Lake Resources Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining 810008 China University of Chinese Academy of Sciences Beijing 100049 China

The effects of maleic anhydride-grafted polypropylene （PP-g-MAH） and maleic anhydride-grafted polyolefin elastomer （POE-g-MAH） on interracial adhesion properties of the polypropylene/magnesium oxysulfate whiskers （PP/MOSw） composites were investigated via mechanical, thermal, ATR-FTIR and rheological tests. Although significant increases in yield strength and Young＇s modulus were observed in PP-g-MAH treated composites, a sharp decline in these properties was observed in POE-g-MAH treated composites. ATR-FTIR results indicated that esterification occurred between the hydroxyl groups of MOSw and the carbonyls of anhydrides of both compatibilizers but POE-g-MAH was still incompatible with the PP matrix, as verified by the presence of shoulder peaks in DTG curves and numerous voids in SEM micrographs. On the other hand, PP-g-MAH was highly compatible with the PP matrix, as evidenced by the peaks in DTG curves and vague interfaces with wrapped melts on the surface of MOSw. Rheological behaviors also confirmed that introducing PP-g-MAH resulted in a transition from liquid-like to solid-like, which was attributed to the stronger interfacial adhesion between MOSw and the PP matrix. POE-g-MAH treated composites, in contrast to PP-g-MAH, maintained liquid- like rheological behaviors as typical molten polymers. There is likely a MOSw network formed in the PP/15PP-g- MAH/15MOSw composite as suggested by the significant deviation of G＇ versus G＂ plots and the two crossover frequencies observed in plots of tan6versus frequency.

关键词： Compatibility Interfacial adhesion Mechanical properties Rheological behaviors

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Strong-coupling superconductivity with Tc above 70 K in Be-decorated monolayer T-graphene

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 99-105页

作者： Liu yang Peng-Fei Liu Hao-dong Liu ya-ping Li Na Jiao Hong-yan Lu Bao-Tian Wang ping Zhang School of Physics and Physical Engineering Qufu Normal UniversityQufu 273165China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China Institute of Applied Physics and Computational Mathematics Beijing 100088China

Using first-principles calculations,we predict a new type of two-dimensional(2D)beryllium(Be)-decorated T-graphene named BeC_(2),where Be atoms are inserted into C–C bonds linking the carbon tetrarings of *** band structure shows that BeC_(2)is metallic,thus,the possible phonon-mediated superconductivity is explored based on the Eliashberg *** calculated electron-phonon coupling(EPC)constantλis up to 4.07,and the corresponding superconducting critical temperature(Tc)is 72.1 K,approaching the liquid nitrogen *** reason for the high Tc is the strong *** it is proved to be an anisotropic single-gap superconductor by analyzing the superconducting gap?kof BeC_(2).The electronic susceptibility calculation shows strong nesting effect in BeC_(2).Since rare 2D superconductors show such a strong EPC constantλwhich originates from the coupling between electrons in C-pzorbital and in-plane vibrations of Be and C atoms,the predicted BeC_(2)provides a new platform for investigating strong EPC 2D superconductor.

关键词： two-dimensional carbon-based superconductor electron-phonon coupling strong coupling high superconducting critical temperature

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New Results in Cooperative Adaptive Optimal Output Regulation

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Journal of Systems Science & Complexity 2024年第1期37卷 253-272页

作者： dong Yuchen GAO Weinan JIANG Zhong-ping State Key Laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyang 110819China Department of Electrical and Computer Engineering Tandon School of EngineeringNew York UniversityBrooklynNY 11201USA

This paper investigates the cooperative adaptive optimal output regulation problem of continuous-time linear multi-agent *** the multi-agent system dynamics are uncertain,solving regulator equations and the corresponding algebraic Riccati equations is challenging,especially for high-order *** this paper,a novel method is proposed to approximate the solution of regulator equations,i.e.,gradient descent *** is worth noting that this method obtains gradients through online data rather than model information.A data-driven distributed adaptive suboptimal controller is developed by adaptive dynamic programming,so that each follower can achieve asymptotic tracking and disturbance ***,the effectiveness of the proposed control method is validated by simulations.

关键词： Adaptive dynamic programming cooperative output regulation gradient descent method multi-agent systems.

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Fabricating functionally graded Fe-Cr-Co permanent magnetic alloys via laser powder bed fusion

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Journal of Iron and Steel Research International 2024年第3期31卷 729-737页

作者： ya-zhou He ya-qing Hou Peng Shen Hao Zhang dong Zhou Hang Su Central Iron and Steel Research Institute Co. Ltd.Beijing 100081China Material Digital R&D Center China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China

Laser powder bed fusion(LPBF)in-situ alloying technology offers the possibility to construct gradient materials with varied structures and *** graded Fe-Cr-Co permanent magnetic alloys were fabricated by LPBF and in-situ alloying mixed powders of Fe,Cr,and Co *** effects of different Fe,Cr and Co contents on the microstructure,magnetic properties and hardness of Fe-Cr-Co alloys prepared by LPBF were *** as-built Fe-Cr-Co alloys present a single body-centered-cubic phase and have a homogeneous distribution of *** mechanical properties and magnetic properties of the compositionally graded sample show a gradient *** the increase in Cr content,the Vickers hardness of the sample increases,and the saturation magnetization of the sample *** optimal magnetic properties in an isotropic state are given as coercivity HcB=21.65 kA/m,remanence Br=0.70 T and energy product(BH)_(max)=5.35 kJ/m^(3),which are comparable to or higher than the reported magnetic properties in an isotropic state prepared by traditional powder *** in-situ alloying technology has the potential to further explore Fe-Cr-Co magnetic materials,such as those consisting of multiple or more constituent elements,and to maximize the compositional flexibility of magnetic materials.

关键词： Fe-Cr-Co alloy Laser powder bed fusion In-situ alloying Functional material Magnetic property

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Optimal proportioning of iron ore in sintering process based on improved multi-objective beluga whale optimisation algorithm

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Journal of Iron and Steel Research International 2024年第7期31卷 1597-1609页

作者： Zong-ping Li Xu-dong Li Xue-tong yan Wu Wen Xiao-xin Zeng Rong-jia Zhu ya-hui Wang Ling-zhi Yi Zhongye Changtian International Engineering Co. Ltd.Changsha 410205HunanChina College of Automation and Electronic Information Xiangtan UniversityXiangtan 411105HunanChina College of Electrical and Information Engineering Hunan UniversityChangsha 410082HunanChina

Proportioning is an important part of sintering,as it affects the cost of sintering and the quality of sintered *** address the problems posed by the complex raw material information and numerous constraints in the sintering process,a multi-objective optimisation model for sintering proportioning was established,which takes the proportioning cost and TFe as the optimisation ***,an improved multi-objective beluga whale optimisation(IMOBWO)algorithm was proposed to solve the nonlinear,multi-constrained multi-objective optimisation *** algorithm uses the con-strained non-dominance criterion to deal with the constraint problem in the ***,the algorithm employs an opposite learning strategy and a population guidance mechanism based on angular competition and two-population competition strategy to enhance convergence and population *** actual proportioning of a steel plant indicates that the IMOBWO algorithm applied to the ore proportioning process has good convergence and obtains the uniformly distributed Pareto ***,compared with the actual proportioning scheme,the proportioning cost is reduced by 4.3361¥/t,and the TFe content in the mixture is increased by 0.0367%in the optimal compromise ***,the proposed method effectively balances the cost and total iron,facilitating the comprehensive utilisation of sintered iron ore resources while ensuring quality assurance.

关键词： Sintering process Proportioning Iron ore Multi-objective beluga whale optimisation algorithm Proportioning cost

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Weighted Composition Operators That Preserve Frames On Weighted Hardy Spaces

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1645-1654页

作者： ya Li dong Rui Liu Guo Xiang Lu School of Mathematical Sciences and LPMC Nankai UniversityTianjin300071P.R.China School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan430073P.R.China

In this paper, we characterize weighted composition operators that preserve frames on the weighted Hardy spaces in the unit disk. In particular, we obtain the symbol properties of the bounded invertible weighted composition operators. Moreover, we establish the equivalence between bounded invertible operators and frame-preserving operators. Furthermore, we show that weighted composition operator preserves frames if and only if it preserves the Riesz bases property. Additionally,we investigate the weighted composition operators that preserve tight or normalized tight frames on the Dirichlet space.

关键词： Weighted composition operators Weighted Hardy spaces frames invertible

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Nuclearity and Finite-Representability in the System of Completely Integral Mapping Spaces

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1197-1214页

作者： Zhe dong Ji Cheng TAO ya Fei ZHAO Department of Mathematics Zhejiang UniversityHangzhou 310027P.R.China Department of Mathematics China Jiliang UniversityHangzhou 310018P.R.China Department of Mathematics Zhejiang International Studies UniversityHangzhou 310023P.R.China

In this paper,we investigate local properties in the system of completely integral mapping *** introduce notions of injectivity,local reflexivity,exactness,nuclearity,finite-represent ability and WEP in the system of completely integral mapping *** we obtain that any finite-dimensional operator space is injective in the system of completely integral mapping *** we prove that C is the unique nuclear operator space and the unique exact operator space in this *** also show that C is the unique operator space which is finitely representable in{T_(n)}n∈Nin this *** corollaries,Kirchberg’s conjecture and QWEP conjecture in the system of completely integral mapping spaces are false.

关键词： Completely integral mapping space injectivity exactness nuclearity finite-representability WEP

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Numerical study on the effective thermal conductivity and thermal tortuosity of porous media with different morphologies

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Science China(Technological Sciences) 2024年第6期67卷 1685-1694页

作者： DU Shen LI dong LI Meng-Jie HE ya-Ling Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an710049China

Effective thermal conductivity and thermal tortuosity are crucial parameters for evaluating the effectiveness of heat conduction within porous *** direct pore-scale numerical simulation method is applied to investigate the heat conduction processes inside porous structures with different *** thermal conduction performances of idealized porous structures are directly compared with real foams across a wide range of *** foam structures are reconstructed using X-ray computed tomography and image processing techniques,while Kelvin and Weaire-Phelan structures are generated through periodic unit cell *** detailed temperature fields inside the porous structures are determined by solving the heat conduction equation at the pore *** results present that the equivalent thermal conductivity of Kelvin and Weaire-Phelan structures is similar to and greater than that of the real foam structure with the same strut *** thermal tortuosity of real foam structure is relatively larger and the heat conduction path becomes straighter by adopting the anisotropic *** thermal tortuosity of the fluid channels for Kelvin,Weaire-Phelan,and real foam structures is close to *** thermal conductivity of porous structures with heat transfer fluid increases as the thermal conductivity ratio of fluid to solid becomes larger.A small porosity of porous media leads to a larger equivalent thermal conductivity due to the dominant contribution of porous skeleton in the heat conduction *** derived from parallel and series models,as well as the Maxwell-Eucken models,provide decent predictions of effective thermal conductivity,with an average error of less than 8%in the entire range of thermal conductivity ratio.

关键词： volumetric solar receiver porous morphology direct pore-scale simulation equivalent thermal conductivity thermal tortuosity empirical correlation

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Regulated polarization degree of upconversion luminescence and multiple anti-counterfeit applications

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Rare Metals 2024年第5期43卷 2172-2183页

作者： dong-ping Wen ping Chen Yi Liang Xiao-Ming Mo Cao-Feng Pan Center On Nanoenergy Research Guangxi Key Laboratory for Relativistic AstrophysicsSchool of Physical Science and TechnologyGuangxi UniversityNanning 530004China Key Laboratory of Micronano Energy and Sensor CAS Center for Excellence in NanoscienceBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 100140China

Polarization upconversion luminescence(PUCL)of lanthanide ions(Ln^(3+))has been widely used in single particle tracking,microfluidics detection,three-dimensional displays,and so ***,no effective strategy has been developed for modulating *** we report a strategy to regulate PUCL in Ho^(3+)-doped NaYF4single nanorods based on the number of upconversion *** constructing a multiphoton upconversion system for Ho^(3+),we regulate the degree of polarization(DOP)of PUCL from 0.590 for two-photon luminescence to 0.929 for three-photon upconversion luminescence(UCL).Furthermore,our strategy is verified from cross-relaxation between Ho^(3+)and Yb^(3+),excitation wavelength,excitation power density,and local site *** this regulation strategy of PUCL has also been achieved in Tm^(3+),with the DOP ranging from 0.233 for two-photon luminescence to 0.925 for four-photon UCL Besides,multi-dimensional anti-counterfeiting display has been explored with *** work provides an effective strategy for regulating PUCL and also provides more opportunities for the development of polarization display optical encoding,anti-counterfeiting,and integrated optical devices.

关键词： Polarization upconversion luminescence Degree of polarization Population density of excited state Number of upconversion photons Polarization anti-counterfeitingdisplay

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