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Historical Changes,Contemporary Characteristics,and Five Transformations of Environmental Design in China
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作者 Tijin Gui 《Journal of Contemporary Educational Research》 2024年第7期7-17,共11页
Starting from the characteristics of modernization in three different historical stages since the founding of the People’s Republic of China,this paper analyses the internal changes in the professional name,subordina... Starting from the characteristics of modernization in three different historical stages since the founding of the People’s Republic of China,this paper analyses the internal changes in the professional name,subordinate disciplines and categories,and professional mission of the environmental design profession,and summarizes the changes in the characteristics of the environmental design profession in 10 aspects such as subordinate disciplines,design objects,design types,cultural characteristics,and aesthetic values on the basis of the results of the analysis,and explores five transformations of the environmental design profession in the process of China’s development in the future.The five transformations in the future development of China are to serve the harmony and beauty of the three major urban and rural spaces with“small and micro-renewal and reconstruction”;to serve the transmission of Chinese culture and the spread of Chinese civilization with“spatial heritage and innovation”;to serve the balance and sufficiency of the four functions of urban and rural settlements with“friendliness and equilibrium”;to serve the intelligence,wisdom,and enjoyment of indoor and outdoor living environment space with“scientific and technological achievements”;and to serve the co-construction,co-management,and sharing of indoor and outdoor public space in urban and rural areas with“public participation.” 展开更多
关键词 Environmental design Historical changes Contemporary characteristics five transformations
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Effects of second phases on mechanical properties and martensitic transformations of ECAPed TiNi and Ti-Mo based shape memory alloys 被引量:8
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作者 宋杰 王立明 +5 位作者 张效宁 孙小刚 江鸿 范志国 谢超英 吴明雄 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第8期1839-1848,共10页
TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing (ECAP) at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the func... TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing (ECAP) at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the functional properties. The effects of both thermodynamically stable and metastable second phases on the mechanical properties and martensitic transformations of these alloys were investigated. It is found that thermodynamically stable Ti2Ni phase has no effect on martensitic transformation and superelasticity of Ti-rich TiNi alloy, thermodynamically stable α phase is harmful for ductility of Ti-Mo-Nb-V-Al alloy, but metastable Ti3Ni4 phase is effective for R phase transformation, martensitic transformation and superelasticity of Ni-rich TiNi alloy. The mechanisms of the second phases on the martensitic transformations and mechanical properties were discussed. 展开更多
关键词 TiNi alloy Ti-Mo based shape memory alloy equal channel angular pressing (ECAP) second phase mechanical property
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基于CTA颅内动脉瘤形态联合PHASES评分对破裂出血预测研究
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作者 王金泉 黄吉淮 谢颖 《影像研究与医学应用》 2024年第4期31-34,共4页
目的:分析头颈部计算机断层扫描血管成像(CTA)联合PHASES评分对颅内动脉瘤(IA)破裂出血的预测价值。方法:回顾性分析2021年10月—2023年9月东莞市长安医院诊治的IA患者临床资料,根据IA破裂出血与否分为IA破裂组(n=46)和IA未破裂组(n=44)... 目的:分析头颈部计算机断层扫描血管成像(CTA)联合PHASES评分对颅内动脉瘤(IA)破裂出血的预测价值。方法:回顾性分析2021年10月—2023年9月东莞市长安医院诊治的IA患者临床资料,根据IA破裂出血与否分为IA破裂组(n=46)和IA未破裂组(n=44),收集两组临床资料,对比两组患者CTA影像瘤体特征参数和PHASES评分结果。采用受试者工作特征(ROC)曲线分析两者联合预测动脉瘤破裂的效能。结果:IA破裂组高血压、糖尿病发生率及PHASES评分均高于IA未破裂组,差异有统计学意义(P <0.05)。两组病灶位置以颈内动脉(ICA)和大脑中动脉(MCA)为主,但IA破裂组病灶位置在MCA的占比为41.30%,高于IA未破裂组的20.45%,瘤体>7 mm的最多(瘤体7~9.9 mm占65.22%),瘤体形态不规则占58.7%,未破裂组病灶位置在ICA最多(68.18%),瘤体<7 mm的居多(75.00%),瘤体形态规则囊状动脉瘤占93.18%,差异有统计学意义(P <0.05)。CTA瘤体特征参数比较,IA破裂组患者瘤颈宽度、瘤体高度、瘤体长度、动脉瘤最大直径、入射夹角、动脉瘤体颈比等参数均高于IA未破裂组,差异有统计学意义(P <0.05)。CTA瘤体特征参数+PHASES评分联合预测曲线下面积为0.916,高于CTA瘤体特征参数(0.901)和PHASES评分(0.731)。结论:CTA瘤体特征参数+PHASES评分联合预测IA患者破裂出血效能最佳。 展开更多
关键词 颅内动脉瘤 破裂出血 CTA phases评分
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Three Cinnamyl β-Cyclodextrins Used as GC Stationary Phases
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作者 萧德庆 凌云 +3 位作者 傅若农 赵郑通 顾峻岭 文玉秀 《Journal of Beijing Institute of Technology》 EI CAS 1998年第3期262-267,共6页
Aim To study the chromatographis beheviors of three new cinnamyl cyclodextrin derivative stationary phases. Mehtods Three new cinnamyl β-cyclodextrins, heptakis-(2, 6-di-O-cinnamyl-3-O-methyl)-β-CD, heptakis-(2, 6-... Aim To study the chromatographis beheviors of three new cinnamyl cyclodextrin derivative stationary phases. Mehtods Three new cinnamyl β-cyclodextrins, heptakis-(2, 6-di-O-cinnamyl-3-O-methyl)-β-CD, heptakis-(2, 6-di-O-cinnamyl-3-O-acetyl-)-β-CD and heptakis-2, 6-di-O-cirinamyl-3-O-trifluoroacetyl)-β-CD were synthesized and coatal on fused-silica capillary columns . Results The new stationary phases have better thermal stability, good column efficiency and excellent mpaxation power for some sutstituted benzene positional isomers. It was found that the introduction of cinnamyl groups has a significant effect on these stationary phases. Conclusion There new subetituted β-CD compounds are very suitable to be ed as gas chromatographic stationary phases. 展开更多
关键词 gas chromatography cinnamyl cyclodextrin derivatives stationary phases
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Superconducting properties of barium in three phases under high pressure from first principles
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作者 周大伟 濮春英 +4 位作者 宋海珍 李根全 宋金璠 卢成 包刚 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第8期601-605,共5页
Electron-phonon coupling (EPC) in the three high-pressure phases of Ba is investigated using a pseudopotentlal planewave method based on density functional perturbation theory. The calculated values of superconducti... Electron-phonon coupling (EPC) in the three high-pressure phases of Ba is investigated using a pseudopotentlal planewave method based on density functional perturbation theory. The calculated values of superconducting critical temperature Tc of Ba-I and Ba-II under pressure are consistent well with the trends observed experimentally. Moreover, Ba-V is found to be superconducting with a maximum Tc exceeding 7.8 K at 45 GPa. With the increase of pressure, the values of Tc increase in Ba I and Ba-Ⅱ but the value of Tc decreases in Ba-V. For Ba-I at pressures below 2 GPa, the increases of logarithmic average frequency Oog and electron-phonon coupling parameters , both contribute to the enhancement of Tc. For all the three phases at pressures above 2 GPa, Tc is found to be primarily determined by Further investigation reveals that for all the three phases, the change in with pressure can be explained mainly by change in the phonon frequency. Thus for Ba-II and Ba-V, although they exhibit completely different superconducting behaviors, their superconductivities have the same origin; the pressure dependence of Tc is determined finally by the pressure dependence of phonon frequency. 展开更多
关键词 high-pressure phase transition SUPERCONDUCTIVITY lattice dynamics
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A Generic Kinematic Model for Three Main Types of Five-axis Machine Tools 被引量:1
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作者 YU Yang WEI Sheng-min +1 位作者 LIU Ping AO Zhi-qiang 《International Journal of Plant Engineering and Management》 2009年第4期243-249,共7页
Material removal is one of the most used processes in manufacturing. Five-axis CNC machines are believed to be the best tools in sculptured surface machining. In this study, a generic and unified kinematic model was d... Material removal is one of the most used processes in manufacturing. Five-axis CNC machines are believed to be the best tools in sculptured surface machining. In this study, a generic and unified kinematic model was developed as a viable alternative to the particular solutions that are only applicable to individual machine configurations. This versatile model is then used to verify the feasibility of the two rotational joints within the kinematic chain of three main types of a five-axis machine-tool. This versatile model is very useful applied to the design of five-axis machine tools. 展开更多
关键词 CNC machining of sculptured surfaces five-axis machine tool configuration kinematic model transformation matrix
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A Wavelet Transform Method to Detect P and S-Phases in Three Component Seismic Data
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作者 Salam Al-Hashmi Adrian Rawlins Frank Vernon 《Open Journal of Earthquake Research》 2013年第1期1-20,共20页
The discrete time wavelet transform has been used to develop software that detects seismic P and S-phases. The detection algorithm is based on the enhanced amplitude and polarization information provided by the wavele... The discrete time wavelet transform has been used to develop software that detects seismic P and S-phases. The detection algorithm is based on the enhanced amplitude and polarization information provided by the wavelet transform coefficients of the raw seismic data. The algorithm detects phases, determines arrival times and indicates the seismic event direction from three component seismic data that represents the ground displacement in three orthogonal directions. The essential concept is that strong features of the seismic signal are present in the wavelet coefficients across several scales of time and direction. The P-phase is detected by generating a function using polarization information while S-phase is detected by generating a function based on the transverse to radial amplitude ratio. These functions are shown to be very effective metrics in detecting P and S-phases and for determining their arrival times for low signal-to-noise arrivals. Results are compared with arrival times obtained by a human analyst as well as with a standard STA/LTA algorithm from local and regional earthquakes and found to be consistent. 展开更多
关键词 Discrete Time WAVELET Transform P and S-phases Automatic Detection Rectilinearity Function
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Darboux Transformations and New Explicit Solutions for a Blaszak-Marciniak Three-Field Lattice Equation
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作者 赵海琼 朱佐农 张京丽 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第7期23-30,共8页
In this paper, the two different Darboux transformations for a Blaszak-Marciniak (BM) three-field lattice equation are constructed. As the applications of the obtained Darboux transformations, new explicit solutions... In this paper, the two different Darboux transformations for a Blaszak-Marciniak (BM) three-field lattice equation are constructed. As the applications of the obtained Darboux transformations, new explicit solutions for the BM lattice are given. We also discuss some properties for these new explicR solutions. Our analysis shows that the explicit solutions possess new characters. 展开更多
关键词 Darboux transformation explicit solution
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The Peak Current Control of Permanent Magnet Brushless DC Machine with Asymmetric Dual-Three Phases 被引量:1
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作者 Chunyuan Bian Xiaoxia Li Guannan Zhao 《CES Transactions on Electrical Machines and Systems》 2018年第1期129-135,共7页
The asymmetric dual-three phase BLDC motor has two sets of stator windings,in which the back EMF coefficients are different.This paper takes advantage of the asymmetric dual-three phase BLDC motor’s structural featur... The asymmetric dual-three phase BLDC motor has two sets of stator windings,in which the back EMF coefficients are different.This paper takes advantage of the asymmetric dual-three phase BLDC motor’s structural features and proposes a new method for the accelerated problem of the BLDC motor operating in the high speed and the constant electromagnetic power.The dual phase windings of the BLDC motor are integrated into the circuit in the starting stage.When the motor’s back EMF value is equal to the terminal voltage value,switch off a set of RST three phase windingswhose back EMF coefficient is bigger and make the other set of stator windingUVWwith smaller back EMF coefficient continue to operate under the rated power.As the motor rotor speed continues to increase,the electromagnetic torque remains unchanged.By using the peak current control strategy,we can deduce that the phase current of the UVW three-phase winding is twice the RSTthree-phase windingwhen the asymmetric dual-three phase BLDC motor operates at high speed and constant power. 展开更多
关键词 Asymmetric dual three phases back emf coefficient peak current control
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Three Dimensional Transformations in the Film Subtitle Translation
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作者 陈志海 DONG Shu-xin REN Hui-ying 《海外英语》 2015年第4期178-179,182,共3页
Film plays an indispensable part in cultural exchange. However, current scholars' studies on the film subtitle translation are less than literary translation. There exists no systematic strategy and theory guiding... Film plays an indispensable part in cultural exchange. However, current scholars' studies on the film subtitle translation are less than literary translation. There exists no systematic strategy and theory guiding it, and there still exists some problems.This paper introduces eco-translatology to film subtitle translation. Eco-translatology proposes that translation is an alternative cycle of translators' adaptation and selection activities in translational eco-environment. The translation method focuses on threedimensional transformation, namely linguistic, cultural and communicative dimensions. 展开更多
关键词 ECO-TRANSLATOLOGY film SUBTITLE translation three DIMENSIONAL transformations TRANSLATIONAL ECO-ENVIRONMENT
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The First Five Years of a Phase Theory for Complex Systems and Networks
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作者 Dan Wang Wei Chen Li Qiu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第8期1728-1743,共16页
In this paper,we review the development of a phase theory for systems and networks in its first five years,represented by a trilogy:Matrix phases and their properties;The MIMO LTI system phase response,its physical in... In this paper,we review the development of a phase theory for systems and networks in its first five years,represented by a trilogy:Matrix phases and their properties;The MIMO LTI system phase response,its physical interpretations,the small phase theorem,and the sectored real lemma;The synchronization of a multi-agent network using phase alignment.Towards the end,we also summarize a list of ongoing research on the phase theory and speculate what will happen in the next five years. 展开更多
关键词 Consensus and synchronization matrix phases multi-agent systems phase theory sectored real lemma small phase theorem.
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Theory and verification of moiréfringes for x-ray three-phase grating interferometer
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作者 单雨征 葛永帅 +5 位作者 杨君 郭大育 蔡学宝 刘晓珂 侯晓文 郭金川 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期532-540,共9页
Dual-phase and three-phase grating x-ray interference is a promising new technique for grating-based x-ray differential phase contrast imaging.Dual-phase grating interferometers have been relatively completely studied... Dual-phase and three-phase grating x-ray interference is a promising new technique for grating-based x-ray differential phase contrast imaging.Dual-phase grating interferometers have been relatively completely studied and discussed.In this paper,the corresponding imaging fringe formula of the three-phase grating interferometer is provided.At the same time,the similarities and differences between the three-phase grating interferometer and the dual-phase grating interferometer are investigated and verified,and that the three-phase grating interferometer can produce large-period moiréfringes without using the analyzing grating is demonstrated experimentally.Finally,a simple method of designing three-phase grating and multi-grating imaging systems from geometric optics based on the thin-lens theory of gratings is presented.These theoretical formulas and experimental results provide optimization tools for designing three-phase grating interferometer systems. 展开更多
关键词 x-ray phase contrast phase grating moiréfringe
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Performance comparison of three artificial neural network methods for classification of electroencephalograph signals of five mental tasks
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作者 Vijay Khare Jayashree Santhosh +1 位作者 Sneh Anand Manvir Bhatia 《Journal of Biomedical Science and Engineering》 2010年第2期200-205,共6页
In this paper, performance of three classifiers for classification of five mental tasks were investigated. Wavelet Packet Transform (WPT) was used for feature extraction of the relevant frequency bands from raw Electr... In this paper, performance of three classifiers for classification of five mental tasks were investigated. Wavelet Packet Transform (WPT) was used for feature extraction of the relevant frequency bands from raw Electroencephalograph (EEG) signal. The three classifiers namely used were Multilayer Back propagation Neural Network, Support Vector Machine and Radial Basis Function Neural Network. In MLP-BP NN five training methods used were a) Gradient Descent Back Propagation b) Levenberg-Marquardt c) Resilient Back Propagation d) Conjugate Learning Gradient Back Propagation and e) Gradient Descent Back Propagation with movementum. 展开更多
关键词 ELECTROENCEPHALOGRAM (EEG) Wavelet Packet Transform (WPT) Support Vector Machine (SVM) Radial Basis Function NEURAL NETWORK (RBFNN) Multilayer Back Propagation NEURAL NETWORK (MLP-BPNN) Brain Computer Interface (BCI)
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The effect of Laves phases and nano-precipitates on the electrochemical corrosion resistance of Mg-Al-Ca alloys under alkaline conditions
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作者 Markus Felten Veronika Chaineux +12 位作者 Siyuan Zhang Ali Tehranchi Tilmann Hickel Christina Scheu Joshua Spille Marta Lipińska-Chwałek Joachim Mayer Benjamin Berkels Marcus Hans Imke Greving Silja Flenner Sandra Sefa Daniela Zander 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第6期2447-2461,共15页
The electrochemical corrosion mechanisms of Mg alloys were extensively studied in previous investigations of different chemical com-positions,modified surface states and various electrolyte conditions.However,recent r... The electrochemical corrosion mechanisms of Mg alloys were extensively studied in previous investigations of different chemical com-positions,modified surface states and various electrolyte conditions.However,recent research focused on the active state of Mg dissolution,leading to unresolved effects of secondary phases adjacent to a stableα-solid solution passive layer.The present study investigates the fundamental electrochemical corrosion mechanisms of three different Laves phases with varying phase morphologies and phase fractions in the passive state of Mg-Al-Ca alloys.The microstructure was characterized by(transmission-)electron microscopy and synchrotron-based transmission X-ray microscopy.The electrochemical corrosion resistance was determined with a standard three-electrode setup and advanced in-situ flow cell measurements.A new electrochemical activity sequence(C15>C36>α-Mg>C14)was obtained,as a result of a stable passive layer formation on theα-solid solution.Furthermore,nm-scale Mg-rich precipitates were identified within the Laves phases,which tend to inhibit the corrosion kinetics. 展开更多
关键词 Laves phase STEM MAGNESIUM Corrosion Passive layer
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Effects of pressure and doping on Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)
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作者 Mingxin Zhang Cuiying Pei +6 位作者 Qi Wang Yi Zhao Changhua Li Weizheng Cao Shihao Zhu Juefei Wu Yanpeng Qi 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2024年第18期147-154,共8页
Recently,the discovery of superconductivity with a critical temperature Tc up to 80 K in Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)(n=2)under pressure has garnered considerable attention.Up to now,the supercondu... Recently,the discovery of superconductivity with a critical temperature Tc up to 80 K in Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)(n=2)under pressure has garnered considerable attention.Up to now,the superconductivity was only observed in La_(3)Ni_(2)O_(7)single crystal grown with the optical-image float-ing zone furnace under oxygen pressure.It remains to be understood the effect of chemical doping on superconducting La_(3)Ni_(2)O_(7)as well as other Ruddlesden-Popper phases.Here,we systematically investi-gate the effect of external pressure and chemical doping on polycrystalline Ruddlesden-Popper phases.Our results demonstrate that the application of pressure and doping effectively tunes the transport prop-erties of Ruddlesden-Popper phases.We find pressure-induced superconductivity up to 86 K in La_(3)Ni_(2)O_(7)polycrystalline sample,while no signatures of superconductivity are observed in La_(2)NiO_(4)and La_(4)Ni_(3)O_(10)polycrystalline samples under high pressure up to 50 GPa.Our study sheds light on the exploration of high-Tc superconductivity in nickelates. 展开更多
关键词 Unconventional superconductivity High pressure NICKELATES Ruddlesden-Popper phases
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General three-dimensional thermal illusion metamaterials
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作者 刘天丰 王兆宸 +1 位作者 朱展 胡润 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期41-47,共7页
Thermal illusion aims to create fake thermal signals or hide the thermal target from the background thermal field to mislead infrared observers,and illusion thermotics was proposed to regulate heat flux with artificia... Thermal illusion aims to create fake thermal signals or hide the thermal target from the background thermal field to mislead infrared observers,and illusion thermotics was proposed to regulate heat flux with artificially structured metamaterials for thermal illusion.Most theoretical and experimental works on illusion thermotics focus on two-dimensional materials,while heat transfer in real three-dimensional(3D)objects remains elusive,so the general 3D illusion thermotics is urgently demanded.In this study,we propose a general method to design 3D thermal illusion metamaterials with varying illusions at different sizes and positions.To validate the generality of the 3D method for thermal illusion metamaterials,we realize thermal functionalities of thermal shifting,splitting,trapping,amplifying and compressing.In addition,we propose a special way to simplify the design method under the condition that the size of illusion target is equal to the size of original heat source.The 3D thermal illusion metamaterial paves a general way for illusion thermotics and triggers the exploration of illusion metamaterials for more functionalities and applications. 展开更多
关键词 thermal illusion thermal metamaterials transformation thermotics
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Pasta Phases in Dense Matter
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作者 SHEN Hong HU Jinniu +2 位作者 JI Fan WU Xuhao JU Min 《原子核物理评论》 CAS CSCD 北大核心 2024年第3期811-817,共7页
The pasta phases are expected to appear in hot supernova matter and cold neutron stars.In supernova matter,the pasta phases with a series of geometric shapes are studied using the compressible liquid-drop(CLD)model,wh... The pasta phases are expected to appear in hot supernova matter and cold neutron stars.In supernova matter,the pasta phases with a series of geometric shapes are studied using the compressible liquid-drop(CLD)model,where nuclear matter separates into a dense liquid phase of nucleons and a dilute gas phase of nucleons and particles.The equilibrium conditions for two coexisting phases are derived by minimization of the total free energy including the surface and Coulomb contributions.Compared to the results considering only spherical nuclei,the inclusion of pasta phases can delay the transition to uniform matter and enlarge the region of nonuniform matter in the phase diagram.It is found that the density ranges of various pasta shapes depend on both the temperature and the proton fraction.The thermodynamic quantities obtained with the pasta phases using the CLD model are consistent with those in the realistic equation of state table for astrophysical simulations using the Thomas-Fermi approximation.The hadron-quark pasta phases occurring in the interior of massive neutron stars are studied using the energy minimization(EM)method,which is analogous to the CLD method for nuclear pasta.It was found that the hadronquark pasta phases could be significantly affected by the model parameters used. 展开更多
关键词 pasta phase supernova matter neutron star
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Disclosing the formation mechanisms of Ag-containing Laves phases at the atomic scale in an Al-Cu-Mg-Ag alloy
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作者 Qilong Liu Xiwu Li +8 位作者 Wei Xiao Zhihui Li Kai Zhu Kai Wen Lizhen Yan Yanan Li Yongan Zhang Manling Sui Baiqing Xiong 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2024年第17期111-121,共11页
In addition to the three well-known Ag-related precipitates(Ω,X′and Z)in the Al-Cu-Mg-Ag alloys,Ag can also be involved in the formation of the as-cast second phases.However,the effect of Ag ad-dition in Al-Cu-Mg-Ag... In addition to the three well-known Ag-related precipitates(Ω,X′and Z)in the Al-Cu-Mg-Ag alloys,Ag can also be involved in the formation of the as-cast second phases.However,the effect of Ag ad-dition in Al-Cu-Mg-Ag alloys has not been completely studied and even the structure of the as-cast Ag-containing phases is still controversial.By employing the focused ion beam(FIB)combined with transmis-sion electron microscopy(TEM)techniques and density functional theory(DFT)calculations,the forma-tion mechanisms of the Ag-containing phases in the as-cast Al-Cu-Mg-Ag alloys have been investigated.The Ag-containing phases are a series of hexagonal C14-type Laves phases with continuously varying Ag concentrations,described as(Al_(x)Cuy Ag_(1-x-y))_(2)Mg.Moreover,the specific occupancy sites of the atoms in(Al_(x)Cuy Ag_(1-x-y))_(2)Mg were determined.The formation of the(Al_(x)Cuy Ag_(1-x-y))_(2)Mg can be attributed to the stronger Ag-induced aggregation of solute atoms in the initial stage and the establishment of strong Ag-X(X=Al,Mg and Ag)bonding in the Ag-containing phases.Furthermore,our experiments have revealed the solidification sequence of Al-Cu-Mg-Ag alloys,and pointed out that(Al_(x)Cuy Ag_(1-x-y))_(2)Mg is formed at a lower temperature(493.9°C)through the reaction L■Al_(2)CuMg+(Al_(x)Cuy Ag_(1-x-y))_(2)Mg.The study could have positive implications for refinement of the Al-Cu-Mg-Ag quaternary phase diagram and promote the composition-property design of novel aluminum alloys based on(Al_(x)Cuy Ag_(1-x-y))_(2)Mg in the future. 展开更多
关键词 Al-Cu-Mg-Ag alloys Laves phases HAADF-STEM First-principles calculation Formation mechanisms
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The occurrence phases and enrichment mechanism of rare earth elements in cobalt-rich crusts from Marcus-Wake Seamounts
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作者 Jingjing Gao Jihua Liu +3 位作者 Hui Zhang Shijuan Yan Xiangwen Ren Quanshu Yan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第8期58-68,共11页
To explore the occurrence phases and enrichment mechanism of rare earth elements(REEs)in cobalt-rich crusts,this study analyzes the mineral composition and REE contents of the samples from Marcus-Wake Seamounts by XRD... To explore the occurrence phases and enrichment mechanism of rare earth elements(REEs)in cobalt-rich crusts,this study analyzes the mineral composition and REE contents of the samples from Marcus-Wake Seamounts by XRD,ICP-OES and ICP-MS.The results show that,(1)the cobalt-rich crusts contain the major crystalline mineral(vernadite),the secondary minerals(quartz,plagioclase and carbonate fluorapatite),and a large amount of amorphous ferric oxyhydroxides(FeOOH).(2)The cobalt-rich crusts contains higher Mn(10.83%to 28.76%)and Fe(6.14%to 18.86%)relative to other elements,and are enriched in REEs,with total REE contents of 1563−3238μg/g and Ce contents of 790−1722μg/g.Rare earth element contents of the old crusts are higher than those of the new crusts.Moreover,the non-phosphatized crusts have positive Ce and negative Y anomalies,and yet the phosphatized crusts have positive Ce and positive Y anomalies,indicating that cobalt-rich crusts is hydrogenetic and REEs mainly come from seawater.(3)Analytical data also show that the occurrence phases of elements in cobalt-rich crusts are closely related to their mineral phases.In the non-phosphatized crusts,REEs are adsorbed by colloidal particles into the crusts(about 67%of REEs in the Fe oxide phase,and about 17%of REEs in the Mn oxide phase).In contrast,in the phosphatized crusts(affected by the phosphatization),REEs may combine with phosphate to form rare earth phosphate minerals,and about 64%of REEs are enriched in the residual phase containing carbonate fluorapatite,but correspondingly the influence of Fe and Mn oxide phases on REEs enrichment is greatly reduced.In addition,the oxidizing environment of seawater,high marine productivity,phosphatization,and slow growth rate can promote the REE enrichment.This study provides a reference for the metallogenesis of cobalt-rich crusts in the Pacific. 展开更多
关键词 cobalt-rich crusts REEs occurrence phase enrichment mechanism Marcus-Wake Seamounts
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Topological phases and edge modes of an uneven ladder
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作者 商文创 韩熠宁 +1 位作者 Shimpei Endo 高超 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第8期154-168,共15页
We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by t... We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by the closure of either direct or indirect bandgaps.It also provides opportunities to explore fundamental concepts concerning band topology and edge modes,including the difference of intracellular and intercellular Zak phases,and the role of the inversion symmetry(IS).We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge accumulation.We also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap,while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band continuum.Furthermore,by projecting to the two sublattices,we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the quasimomentum.In this way,the topological phases can be efficiently extracted through winding numbers.We propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments. 展开更多
关键词 ladder model symmetry-protected topological phase topological invariant bulk-boundary correspondence
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