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Preparation and Properties of Paraffin/PMMA Shape-stabilized Phase Change Material for Building Thermal Energy Storage 认领
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作者 孟多 ZHAO Kang +1 位作者 WANG Anqi WANG Baomin 《武汉理工大学学报:材料科学英文版》 SCIE EI CAS 2020年第1期231-239,共9页
The composite phase change material(PCM) consisting of phase change paraffin(PCP) and polymethyl methacrylate(PMMA) was prepared as a novel type of shape-stabilized PCM for building energy conservation through the met... The composite phase change material(PCM) consisting of phase change paraffin(PCP) and polymethyl methacrylate(PMMA) was prepared as a novel type of shape-stabilized PCM for building energy conservation through the method of bulk polymerization. The chemical structure, morphology, phase change temperature and enthalpy, and mechanical properties of the composite PCM were studied to evaluate the encapsulation effect of PMMA on PCP and determine the optimal composition proportion. FTIR and SEM results revealed that PCP was physically immobilized in the PMMA so that its leakage from the composite was prevented. Based on the thermo-physical and mechanical properties investigations, the optimal mass fraction of PCP in the composite was determined as 70%. The phase change temperature of the composite was close to that of PCP, and its latent heat was equivalent to the calculated value according to the mass fraction of PCP in the composite. For estimating the usability in practical engineering, thermal stability, reliability and temperature regulation performance of the composite were also researched by TG analysis, thermal cycling treatments and heating-cooling test. The results indicated that PCP/PMMA composite PCM behaved good thermal stability depending on the PMMA protection and its latent heat degraded little after 500 thermal cycling. Temperature regulation performance of the composite before and after thermal cycling was both noticeable due to its latent heat absorption and release in the temperature variation processes. The PCP/PMMA phase change plate was fabricated and applied as thermal insulator in miniature concrete box to estimate its temperature regulation effect under the simulated environmental condition. It can be concluded that this kind of PCP/PMMA shape-stabilized PCM with the advantages of no leakage, suitable phase change temperature and enthalpy, good thermal stability and reliability, and effective temperature regulation performance have much potential for thermal energy storage in building energy 展开更多
关键词 shape-stabilized PHASE CHANGE material PHASE CHANGE PARAFFIN polymethyl METHACRYLATE temperature regulation BUILDING energy conservation
Crystal phase-controlled growth of PtCu and PtCo alloys on 4H Au nanoribbons for electrocatalytic ethanol oxidation reaction 认领
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作者 Jie Wang Jian Zhang +17 位作者 Guigao Liu Chongyi Ling Bo Chen Jingtao Huang Xiaozhi Liu Bing Li An-Liang Wang Zhaoning Hu Ming Zhou Ye Chen Hongfei Cheng Jiawei Liu Zhanxi Fan Nailiang Yang Chaoliang Tan Lin Gu Jinlan Wang Hua Zhang 《纳米研究:英文版》 SCIE EI CAS CSCD 2020年第7期1970-1975,共6页
Crystal phase can greatly affect the physicochemical properties and applications of nanomaterials.However,it stil remains a great challenge to synthesize nanostructures with the same composition and morphology but dif... Crystal phase can greatly affect the physicochemical properties and applications of nanomaterials.However,it stil remains a great challenge to synthesize nanostructures with the same composition and morphology but different phases in order to explore the phase-dependent properties and applications.Herein,we report the crystal phase-controlled synthesis of PtCu alloy shells on 4H Au nanoribbons(NRBs),referred to as 4H-Au NRBs,to form the 4H-Au@PtCu core-shell NRBs.By tuning the thickness of PtCu,4H-PtCu and face-centered cubic(cc)phase PICu(cc-PtCu)alloy shells are successtully grown on the 4H-Au NRB cores.This thickness-dependent phase-controlled growth strategy can also be used to grow PtCo alloys with 4H or fcc phase on 4H-Au NRBs.Significantly,when used as electrocatalysts for the ethanol oxidation reaction(EOR)in alkaline media,the 4H-Au@4H-PtCu NRBs show much better EOR performance than the 4H-Au@fcc-PtCu NRBs,and both of them possess superior performance compared to the commercial Pt black.Our study provides a strategy on phase-contolled synthesis of nanomaterials used for crystal phase-dependent applications. 展开更多
关键词 crystal phase 4H hexagonal face-ce ntered cubic ethanol oxidation reaction phase engineering of nanomaterials
Competition between Liquid-liquid De-mixing, Crystallization, and Glass Transition in Solutions of PLA of Different Stereochemistry and DEET 认领
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作者 Chanita Sungkapreecha Walter WFocke René Androsch 《高分子科学:英文版》 SCIE CAS CSCD 2020年第2期174-178,I0007共6页
Liquid-liquid(L-L)de-mixing and vitrification of solutions of either crystallizable poly(L-lactic acid)(PLLA)or non-crystallizable poly(D/L-lactic acid)(PDLLA)with 50 m%N,N-diethyl-3-methylbenzamide(DEET)were analyzed... Liquid-liquid(L-L)de-mixing and vitrification of solutions of either crystallizable poly(L-lactic acid)(PLLA)or non-crystallizable poly(D/L-lactic acid)(PDLLA)with 50 m%N,N-diethyl-3-methylbenzamide(DEET)were analyzed by calorimetry and cloud-point measurements,which allows drawing conclusions about the effect of polymer stereochemistry on the phase behavior.Regardless of the PLA stereochemistry,vitrification of the solutions on fast cooling,hindering crystallization of PLLA,occurred below-20℃ and suppressed prior L-L de-mixing.The experimental results prove that crystallization in samples containing crystallizable PLLA,observed at around 55℃ on slow cooling,is not preceded by L-L de-mixing. 展开更多
关键词 CRYSTALLIZATION PLA DEET LIQUID-LIQUID PHASE SEPARATION Thermally-induced PHASE separation(TIPS)
Phase equilibria in low basicity region of CaO-SiO2-Nb2O5-(5 wt%,10 wt%,15 wt%) La2O3 system 认领
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作者 Jiyu Qiu Chengjun Liu +1 位作者 Zhengyue Liu Zhe Yu 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2020年第1期100-107,共8页
The lack of thermodynamic information,such as primary phase fields and liquidus temperatures,in the CaO-SiO2-Nb2O5-La2O3 quaternary system phase diagram has restricted the comprehensive utilization of the niobium(Nb) ... The lack of thermodynamic information,such as primary phase fields and liquidus temperatures,in the CaO-SiO2-Nb2O5-La2O3 quaternary system phase diagram has restricted the comprehensive utilization of the niobium(Nb) and rare earth(RE) resources.In this work,the phase equilibria in low basicity region(w(CaO)/w(SiO2)<1) of CaO-SiO2-Nb2O5-(0-15 wt%)La2O3 system at 1373-1873 K were experimentally studied by thermodynamic equilibrium experiment,and then,the results were analyzed by X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy dispersive spectrometry(EDS).Additionally,an optimized method was proposed to process the compositions of equilibrium liquid phases at different temperatures.According to the experimental results,the univariate line between CaNb2O6,SiO2 and LaNbO4 primary phase fields,interface between CaNb2O6 and SiO2 primary phase fields and isothermal liquidus surfaces in SiO2 primary phase field were determined.Finally,the spatial phase diagram of CaO-SiO2-Nb2O5-La2O3 within specific region was constructed,and furthermore,the phase diagram was also presented in CaO-SiO2-Nb2O5 pseudo-ternary system with w(La2O3)=5 wt%,10 wt% and 15 wt%.The research results have guiding significance for the improvement of related phase diagram and the comprehensive utilization of Nb and RE resources. 展开更多
关键词 PHASE equilibria CaO-SiO2-Nb2O5-La2O3 Liquidus surface Primary PHASE field Rare earths
A method based on Chinese remainder theorem with all phase DFT for DOA estimation in sparse array 认领
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作者 CAO Chenghu ZHAO Yongbo +2 位作者 PANG Xiaojiao XU Baoqing CHEN Sheng 《系统工程与电子技术:英文版》 SCIE EI CSCD 2020年第1期1-11,共11页
This paper takes further insight into the sparse geometry which offers a larger array aperture than uniform linear array(ULA)with the same number of physical sensors.An efficient method based on closed-form robust Chi... This paper takes further insight into the sparse geometry which offers a larger array aperture than uniform linear array(ULA)with the same number of physical sensors.An efficient method based on closed-form robust Chinese remainder theorem(CFRCRT)is presented to estimate the direction of arrival(DOA)from their wrapped phase with permissible errors.The proposed algorithm has significantly less computational complexity than the searching method while maintaining similar estimation precision.Furthermore,we combine all phase discrete Fourier transfer(APDFT)and the CFRCRT algorithm to achieve a considerably high DOA estimation precision.Both the theoretical analysis and simulation results demonstrate that the proposed algorithm has a higher estimation precision as well as lower computation complexity. 展开更多
关键词 direction of arrival(DOA) wrapped PHASE closedform robust Chinese REMAINDER theorem(CFRCRT) all PHASE discrete Fourier transfer(APDFT)
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一种新型电力电容电感测试校准装置 认领
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作者 林勇 赵斯衎 张杰梁 《电子测试》 2020年第15期20-21,105,共3页
介绍了一种新型的电力电容电感测试校准装置,将电力电容电感测试仪需要测量的电容值、电感值、电阻值巧妙的转换为电压电流的相位关系,利用移相电路、电流放大调整电路来实现电力电容电感测试电容值、电感值、电阻值量值溯源的目的。
关键词 电容 电感 电阻 相位 移相
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Paving the road toward the use ofβ-Fe2O3 in solar water splitting:Raman identification,phase transformation and strategies for phase stabilization 认领
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作者 Ningsi Zhang Xin Wang +4 位作者 Jianyong Feng Huiting Huang Yongsheng Guo Zhaosheng Li Zhigang Zou 《国家科学评论:英文版》 SCIE EI CSCD 2020年第6期1059-1067,共9页
Althoughβ-Fe2O3 has a high theoretical solar-to-hydrogen efficiency because of its narrow band gap,the study ofβ-Fe2O3 photoanodes for water splitting is elusive as a result of their metastable nature.Raman identifi... Althoughβ-Fe2O3 has a high theoretical solar-to-hydrogen efficiency because of its narrow band gap,the study ofβ-Fe2O3 photoanodes for water splitting is elusive as a result of their metastable nature.Raman identification ofβ-Fe2O3 is theoretically and experimentally investigated in this study for the first time,thus clarifying the debate about its Raman spectrum in the literature.Phase transformation ofβ-Fe2O3 toα-Fe2O3 was found to potentially take place under laser and electron irradiation as well as annealing.Herein,phase transformation ofβ-Fe2O3 toα-Fe2O3 was inhibited by introduction of Zr doping,andβ-Fe2O3 was found to withstand a higher annealing temperature without any phase transformation.The solar water splitting photocurrent of the Zr-dopedβ-Fe2O3 photoanode was increased by 500%compared to that of the pureβ-Fe2O3 photoanode.Additionally,Zr-dopedβ-Fe2O3 exhibited very good stability during the process of solar water splitting.These results indicate that by improving its thermal stability,metastableβ-Fe2O3 film is a promising photoanode for solar water splitting. 展开更多
关键词 solar energy conversion metastable phase phase transformation iron oxide photoelectrochemical water splitting
Hermite-Gaussian beams with sinusoidal vortex phase modulation 认领
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作者 王冠学 李月 +2 位作者 单新治 苗玉 高秀敏 《中国光学快报:英文版》 SCIE EI CAS CSCD 2020年第4期76-80,共5页
In this Letter,vortex phase and sinusoidal phase modulations of Hermite-Gaussian beams are studied theoretically and experimentally.The coding method of the experiment is introduced in detail,and the evolution law of ... In this Letter,vortex phase and sinusoidal phase modulations of Hermite-Gaussian beams are studied theoretically and experimentally.The coding method of the experiment is introduced in detail,and the evolution law of focus under different beam order(m,n)and topological charge(l)is given.In order to verify the accuracy of the generation experiment,the optical field distribution under sinusoidal vortex modulation is analyzed deeply.The relevant analysis and methods provided in this Letter have certain practical significance for the development of laser mode analysis,optical communication,and other fields. 展开更多
关键词 Hermite-Gaussian beams phase modulation sinusoidal vortex phase modulation spatial light modulator focus mode
Liquid-liquid phase separation in biology: mechanisms,physiological functions and human diseases 认领
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作者 Hong Zhang Xiong Ji +7 位作者 Pilong Li Cong Liu Jizhong Lou Zheng Wang Wenyu Wen Yue Xiao Mingjie Zhang Xueliang Zhu 《中国科学:生命科学英文版》 SCIE CAS CSCD 2020年第7期953-985,共33页
Cells are compartmentalized by numerous membrane-enclosed organelles and membraneless compartments to ensure that a wide variety of cellular activities occur in a spatially and temporally controlled manner. The molecu... Cells are compartmentalized by numerous membrane-enclosed organelles and membraneless compartments to ensure that a wide variety of cellular activities occur in a spatially and temporally controlled manner. The molecular mechanisms underlying the dynamics of membrane-bound organelles, such as their fusion and fission, vesicle-mediated trafficking and membrane contactmediated inter-organelle interactions, have been extensively characterized. However, the molecular details of the assembly and functions of membraneless compartments remain elusive. Mounting evidence has emerged recently that a large number of membraneless compartments, collectively called biomacromolecular condensates, are assembled via liquid-liquid phase separation(LLPS). Phase-separated condensates participate in various biological activities, including higher-order chromatin organization,gene expression, triage of misfolded or unwanted proteins for autophagic degradation, assembly of signaling clusters and actin-and microtubule-based cytoskeletal networks, asymmetric segregations of cell fate determinants and formation of pre-and post-synaptic density signaling assemblies. Biomacromolecular condensates can transition into different material states such as gel-like structures and solid aggregates. The material properties of condensates are crucial for fulfilment of their distinct functions, such as biochemical reaction centers, signaling hubs and supporting architectures. Cells have evolved multiple mechanisms to ensure that biomacromolecular condensates are assembled and disassembled in a tightly controlled manner. Aberrant phase separation and transition are causatively associated with a variety of human diseases such as neurodegenerative diseases and cancers. This review summarizes recent major progress in elucidating the roles of LLPS in various biological pathways and diseases. 展开更多
关键词 phase separation phase transition TRANSCRIPTION asymmetric division postsynaptic density AUTOPHAGY
Creation of topological vortices using Pancharatnam-Berry phase liquid crystal holographic plates 认领
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作者 郭旭岳 钟进展 +3 位作者 李鹏 魏冰妍 刘圣 赵建林 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第4期89-93,共5页
Recently,physical fields with topological configurations are evoking increasing attention due to their fascinating structures both in fundamental researches and practical applications.Therein,topological light fields,... Recently,physical fields with topological configurations are evoking increasing attention due to their fascinating structures both in fundamental researches and practical applications.Therein,topological light fields,because of their unique opportunity of combining experimental and analytical studies,are attracting more interest.Here,based on the Pancharatnam-Berry(PB)phase,we report the creation of Hopf linked and Trefoil knotted optical vortices by using phaseonly encoded liquid crystal(LC)holographic plates.Utilizing scanning measurement and the digital holographic interference method,we accurately locate the vortex singularities and map these topological nodal lines in three-dimensions.Compared with the common methods realized by the spatial light modulator(SLM),the phase-only LC plate is more efficient.Meanwhile,the smaller pixel size of the LC element reduces the imperfection induced by optical misalignment and pixellation.Moreover,we analyze the influence of the incident beam size on the topological configuration. 展开更多
关键词 TOPOLOGICAL VORTICES Pancharatnam-Berry PHASE liquid crystal PHASE SINGULARITY HOLOGRAM
Deep learning approach to detect seizure using reconstructed phase space images 认领
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作者 N.Ilakiyaselvan A.Nayeemulla Khan A.Shahina 《生物医学研究杂志:英文版》 CAS CSCD 2020年第3期240-250,共11页
Epilepsy is a chronic neurological disorder that affects the function of the brain in people of all ages.It manifests in the electroencephalogram(EEG) signal which records the electrical activity of the brain.Various ... Epilepsy is a chronic neurological disorder that affects the function of the brain in people of all ages.It manifests in the electroencephalogram(EEG) signal which records the electrical activity of the brain.Various image processing,signal processing,and machine-learning based techniques are employed to analyze epilepsy,using spatial and temporal features.The nervous system that generates the EEG signal is considered nonlinear and the EEG signals exhibit chaotic behavior.In order to capture these nonlinear dynamics,we use reconstructed phase space(RPS) representation of the signal.Earlier studies have primarily addressed seizure detection as a binary classification(normal vs.ictal) problem and rarely as a ternary class(normal vs.interictal vs.ictal)problem.We employ transfer learning on a pre-trained deep neural network model and retrain it using RPS images of the EEG signal.The classification accuracy of the model for the binary classes is(98.5±1.5)% and(95±2)% for the ternary classes.The performance of the convolution neural network(CNN) model is better than the other existing statistical approach for all performance indicators such as accuracy,sensitivity,and specificity.The result of the proposed approach shows the prospect of employing RPS images with CNN for predicting epileptic seizures. 展开更多
关键词 EPILEPSY reconstructed phase space convolution neural network reconstructed phase space image AlexNet SEIZURE
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Study of nucleon-nucleon and alphanucleon elastic scattering by the Manning-Rosen potential 认领
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作者 A K Behera J Bhoi +1 位作者 U Laha B Khirali 《理论物理通讯:英文版》 SCIE CAS CSCD 2020年第7期60-64,共5页
Although often used in molecular dynamics,in this work the Manning-Rosen potential is parameterized to compute the scattering phase shifts for the nucleon-nucleon and the alphanucleon systems by exploiting the standar... Although often used in molecular dynamics,in this work the Manning-Rosen potential is parameterized to compute the scattering phase shifts for the nucleon-nucleon and the alphanucleon systems by exploiting the standard phase function method.We obtain excellent agreement in phase shifts with the more sophisticated calculations up to partial waves l=2. 展开更多
关键词 phase function method Manning-Rosen potential scattering phase shifts nucleon-nucleon and the alpha-nucleon systems
Phase equilibria of low-Y side in Mg-Zn-Y system at 400℃ 认领
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作者 Bo-Shu Liu Hong-Xiao Li +2 位作者 Yu-Ping Ren Min Jiang Gao-Wu Qin 《稀有金属:英文版》 SCIE EI CAS CSCD 2020年第3期262-269,共8页
Phase equilibrium relations of the Mg-Zn-Y system in the low-Y side at 400℃were investigated by alloy-equilibrated method,combined with thermal analysis.The results show that there is a liquid phase which could be in... Phase equilibrium relations of the Mg-Zn-Y system in the low-Y side at 400℃were investigated by alloy-equilibrated method,combined with thermal analysis.The results show that there is a liquid phase which could be in equilibrium with an a-Mg solid solution and an icosahedral quasicrystal I phase in the low-Y side of the Mg-Zn-Y system at 400℃.The liquid phase region originates from the binary Mg-Zn system and extends to 0.4 at%Y in the Mg-Zn-Y system.Besides,the hexagonal structure H phase,fee W phase and LPSO phase(X phase)are in equilibrium with a-Mg.With Y/Zn(atomic ratio,the same as follows)increasing,there exist four three-phase regions consisting of I+liquid+α-Mg,I+H+α-Mg,H+W+α-Mg and W+X+α-Mg,respectively,in the low-Y side of the isothermal section at 400℃.The twophase region a-Mg+I phase exists between I+H+aMg and I+liquid+a-Mg.In this two-phase region,the Y/Zn ratio is in the range of 0.14-0.17;and a three-phase region of a-Mg+I phase+H phase appears when Y/Zn ratio comes up to 0.17-0.27.Not I but W phase is in equilibrium with a-Mg,when Y/Zn ratio>0.27.The system is in liquid-state phase equilibrium,when Y/Zn ratio<0.14. 展开更多
关键词 Mg-Zn-Y system PHASE equilibrium ICOSAHEDRAL QUASICRYSTAL PHASE Solid SOLUBILITY
文章速递Investigation on the 773K isothermal section of Ho-Ni-Si ternary phase diagram by X-ray powder diffraction and magnetic property of Ho3NiSi2 alloy 认领
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作者 Xiang Chen Jixin Gong +2 位作者 Jiaojiao Luo Wenxuan Yang Xian Qing 《稀土学报:英文版》 SCIE EI CAS CSCD 2020年第9期969-975,I0002,共8页
The isothermal section of the Ho-Ni-Si system at 773 K was constructed by X-ray powder diffraction(XRD)in this work.The system contains sixteen known type structure compounds TiNiSi-type HoNiSi,BaAl4-type HoNi2Si2,CeN... The isothermal section of the Ho-Ni-Si system at 773 K was constructed by X-ray powder diffraction(XRD)in this work.The system contains sixteen known type structure compounds TiNiSi-type HoNiSi,BaAl4-type HoNi2Si2,CeNiSi2-type HoNiSi2,U1Co3Si5-type Ho2Ni3Si5,SmNiGe3-type HoNiSi3,Ce3 Ni6Si2-type Ho3Ni6Si2,ThMn12-type HoNi10Si2,YPd2Si-type HoNi2Si,YNi5Si3-type HoNi5Si3,YNi4Si-type HoNi4Si,Gd3NiSi2-type Ho3NiSi2,YNi6Si6-type HoNi6Si6.AlB2-type Ho2NiSi3,AlB2-type Ho3Ni2Si4,AlB2-type Ho4NiSi7,Gd3Ru4Al12-type Ho8Ni31Si11,and one unknown type structure compound Ho5Ni2Si3.At the same time,one unknown structure new phase Ho37Ni3Si60 was observed.In ternary compounds,Ho2NiSi3 and Ho4NiSi7 have the solid solution phenomena;the solid solution ranges are about Ho33.3Ni18.7-9.7Si-48.0-57.0 and Ho33.Ni-8.3-2.6Si-58.3-64.1,respectively.At the same time,quasi-binary solid solutions were detected at 773 K for Ho2Ni17,HoNi5,Ho2Ni7,HoNi3,HoNi2,HoNi,HoSi.Other binary compounds of the Ho-Ni-Si system do not show any visible solubility.The magnetic property studies show that Ho3NiSi2 compound has two successive magnetic phase transitions in a low field:a spinreorientation transition at TSR=10 K and a second order ferromagnetic(FM)-paramagnetic(PM)transition at Tc=37 K. 展开更多
关键词 Ternary alloys Ho-Ni-Si phase diagram Solid solution X-ray diffraction Rare earths
Development of high-coercivity state in melt-spun Fe41Pd41B8Si6P4 ribbons 认领
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作者 Oksana Aleksandrovna Golovnia Nina Ivanovna Vlasova +4 位作者 Aleksandr Gervasievich Popov Vasiliy Semenovich Gaviko Vladimir Vladimirovich Popov Jr. Andrey Vladimirovich Protasov Arti Kashyap 《稀有金属:英文版》 SCIE EI CAS CSCD 2020年第1期76-83,共8页
The phase transformation and magnetic hysteresis properties of melt-spun Fe41 Pd41 B8 Si6 P4 ribbons subjected to the annealing at temperatures of 500-550℃were studied after holding for 0.1-60.0 h by transmission ele... The phase transformation and magnetic hysteresis properties of melt-spun Fe41 Pd41 B8 Si6 P4 ribbons subjected to the annealing at temperatures of 500-550℃were studied after holding for 0.1-60.0 h by transmission electron microscopy(TEM),X-ray diffraction(XRD)and thermomagnetic analysis.The additions of P,B and Si to the FePd alloy allowed us to achieve the coercivity of124 kA·m-1,which is 2.6 times higher than that of the melt-spun ribbons of the binary equiatomic FePd alloy.The high-coercivity Fe41Pd41B8 Si6 P4 alloy is nanocrystalline and is composed of the ordered L10-phase grains approximately 40 nm in size and inclusions of the Fe2(P,B)and Pd2(Si,B)phases.The coercivity kinetics is controlled by the phase transformation which can be divided into three stages:transformation from the bcc structure to nanosized regions of the fee and Fe2 P phases;transformation from the fee to L10 nanosized regions with somewhat different degrees of tetragonality and their ordering;and extensive growth of the weight fraction of L10 phase from the fee nanosized regions.P and B atoms occupy interstitial sites in the iron plane of L10 lattice,thus decreasing its Curie temperature(TC). 展开更多
关键词 Fe-Pd-P-B-Si MELT SPINNING L10 NANOSTRUCTURED materials Phase transformation Magnetic measurements
Theoretical investigation on the stability, mechanical and thermal properties of the newly discovered MAB phase Cr4AlB4 认领
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作者 Fu-Zhi Dai Haiming Zhang +1 位作者 Huimin Xiang Yanchun Zhou 《材料科学技术:英文版》 SCIE EI CAS CSCD 2020年第4期161-166,共6页
The nanolaminated MAB phases have attracted great research interests in recent years due to their similarities to MAX phases,which display both metallic and ceramic-like properties.In the present work,a newly discover... The nanolaminated MAB phases have attracted great research interests in recent years due to their similarities to MAX phases,which display both metallic and ceramic-like properties.In the present work,a newly discovered MAB phase Cr4AlB4 was investigated by first principles calculations.Energy evaluations indicate that Cr4AlB4 can be synthetized in Al lean condition,which can further transform to Cr2AlB2 in Al rich condition.The full set of elastic properties and their dependences on temperature,ideal strengths under different tensile and shear deformations,and thermal expansions of Cr4AlB4 were predicted.The results reveal that the properties of Cr4AlB4 are dominated by the layered crystal structure and weak bonding nature between Al and Cr2B2 layers,including low elastic stiffness and large thermal expansion along[010]direction(the stacking direction of Al and Cr2B2 layers),low shear resistances in(010)plane,and preferentially cleavage along and/or shear in(010)plane.Therefore,it suggests that Cr4AlB4 displays similar mechanical properties to MAX phases,including readily machinable,thermal shock resistant,and damage tolerant.In combination with the fact that Cr,Al and B all can form dense oxides to protect the material from further oxidation,Cr4AlB4 is regarded as a promising high temperature ceramic. 展开更多
关键词 MAB PHASE Cr4AlB4 FIRST-PRINCIPLES Mechanical PROPERTIES Thermal PROPERTIES
Controllable photonic spin Hall effect with phase function construction 认领
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作者 YANLIANG HE ZHIQIANG XIE +7 位作者 BO YANG XUEYU CHEN JUNMIN LIU HUAPENG YE XINXING ZHOU YING LI SHUQING CHEN DIANYUAN FAN 《光子学研究:英文版》 SCIE EI CSCD 2020年第6期963-971,共9页
Photonic spin Hall efect(SHE)provides new opportunities for achieving spin-based photonics applications.However,flexibly manipulating the spin-dependent sltting(SDS)of photonic SHE and imposing extra phase modulation ... Photonic spin Hall efect(SHE)provides new opportunities for achieving spin-based photonics applications.However,flexibly manipulating the spin-dependent sltting(SDS)of photonic SHE and imposing extra phase modulation on the two spin components are always a challenge.Here,a controllable SHE mechanism based on phase function construction is reported.It is conduded that the phases with specific functional structures performing a coordinate translation are equivalent to integrating a gradient phase to the original phases.Hence,the original phase can be used for independent phase modulation,and the gradient phase originating from the co-ordinate translation is capable of manipulating the SDS.A metasurface with Pancharatnam-Berry phase that can impose conjugate phases to the two spin components of light is fabricated to verify this mechanism.By shifing the light position,the SDS is continuously manipulated in the visible region,which is successfully used for detecting the polarization llipticity.The extra phase modulation is also performed with the original phase and thus enables measuring singular beams.It is anticipated that the controllable SHE manipulation method may open new avenues in the fields of spin photonics,optical sensing,optical communications,etc. 展开更多
关键词 mechanism. PHASE FUNCTION
Transformation between nanosheets and nanowires structure in MnO2 upon providing Co^2+ions and applications for microwave absorption 认领
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作者 Lulu Song Yuping Duan +1 位作者 Jia Liu Huifang Pang 《纳米研究:英文版》 SCIE EI CAS CSCD 2020年第1期95-104,共10页
The phase transition process of the MnO2 phase with increases in Co^2+doping can be described by the Ouroboros symbol.The undoped sample is pureδ-MnO2 with nanosheets structures.Then a small amount of Co^2+ions chang... The phase transition process of the MnO2 phase with increases in Co^2+doping can be described by the Ouroboros symbol.The undoped sample is pureδ-MnO2 with nanosheets structures.Then a small amount of Co^2+ions changes the final products and generatesα-MnO2 nanofibres in theδ-MnO2 matrix.The products become pureα-MnO2 with an appropriate amount of Co added.However,when the Co amount continues to increase,the amount ofα-MnO2 decreases in the products and turns back to form pureδ-MnO2 in the end.Analysing the electromagnetic absorption performance,the relationship between the properties and the proportion ofδ-MnO2/α-MnO2 in the powders adjusted by Co^2+doping has been explored,and the composites ofδ-/α-MnO2 show better absorption ability than the single-phase samples.As a result,the optimal reflection loss(RL)is−54.8 dB,and the effective absorption bandwidth can cover the Ku band at a thickness of 2.2 mm and the X band at a thickness of 3.1 mm with 50 wt.%filler loading ratios.This research might shed new light on the improvement of novel microwave absorption materials. 展开更多
关键词 phase transitions SELF-ASSEMBLY impedance matching microwave absorption
Mechanism and mitigation of spontaneous Ga whisker growth on Cr2GaC 认领
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作者 ZHANG PeiGen DING JianXiang +5 位作者 LIU YuShuang YANG Li TIAN WuBian OUYANG Jian ZHANG YaMei SUN ZhengMing 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2020年第3期440-445,共6页
Spontaneous growth of A-element whiskers on Mn+1AXn(MAX for short) phase materials poses a barrier to their practical applications, since it casts doubts on their stability. In this study, Ga whisker growth on sintere... Spontaneous growth of A-element whiskers on Mn+1AXn(MAX for short) phase materials poses a barrier to their practical applications, since it casts doubts on their stability. In this study, Ga whisker growth on sintered Cr2GaC samples was investigated. The elemental source for spontaneous growth of Ga whiskers is identified as the free Ga contained in the Cr2GaC material, not the lattice atoms from Cr2GaC grains, which removes the doubts on the stability of Cr2GaC material. The growth behavior and morphologies of the Ga whiskers follow a new catalysis-based model, with cleavage planes of Cr2GaC grains involved as nucleation sites. This model explains and predicts well the growth behavior of the whiskers. The mitigation strategy based on this model is in principle simple: to prevent free Ga in Cr2GaC material or limit it to a certain level;to avoid cleavage plane of Cr2GaC grains;to achieve high density of the Cr2GaC material. 展开更多
关键词 MAX phase WHISKER GROWTH NUCLEATION model MITIGATION strategy
Automatic wavefront reconstruction on single interferogram with spatial carrier frequency using Fourier transform 认领
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作者 张洪鑫 张旭 +1 位作者 仇浩然 周昊 《光电子快报:英文版》 EI 2020年第1期75-80,共6页
Optical interferometry can be applied to obtain the wavefront phase and reconstruct the three-dimensional wavefront by analyzing interference fringes. Single interferogram analysis based on two-dimensional Fourier tra... Optical interferometry can be applied to obtain the wavefront phase and reconstruct the three-dimensional wavefront by analyzing interference fringes. Single interferogram analysis based on two-dimensional Fourier transform is proposed. This method just needs to acquire and analyze single interferogram to solve the wavefront phase. Compared with phase-shift method, Single interferogram analysis can reduce experiment cost and the limitation of measuring e nvironment like vibration, airflow and noise, and meet the requirement of real-time and dynamic interferometry. Because the wavefront phase information is included in the carrier frequency components of single interferogram, an image edge detection method is used to automatically extract the center and boundary of the first-order carrier component of the spatial spectrum of the interferogram in the frequency domain. 展开更多
关键词 domain. phase. INTERFEROMETRY
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