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H–He Demixing Driven by Anisotropic Hydrogen Diffusion 被引量:1
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作者 Xiaoju Chang Dongdong Kang +1 位作者 Bo Chen jiayu dai 《Chinese Physics Letters》 2025年第5期33-42,共10页
The dynamics of phase separation in H–He binary systems within gas giants such as Jupiter and Saturn exhibit remarkable complexity, yet lack systematic investigation. Through large-scale machine-learning-accelerated ... The dynamics of phase separation in H–He binary systems within gas giants such as Jupiter and Saturn exhibit remarkable complexity, yet lack systematic investigation. Through large-scale machine-learning-accelerated molecular dynamics simulations spanning broad temperature-pressure-composition(2000–10000 K, 1–7 Mbar,pure H to pure He) regimes, we systematically determine self and mutual diffusion coefficients in H–He systems and establish a six-dimensional framework correlating temperature, pressure, helium abundance, phase separation degree, diffusion coefficients, and anisotropy. Key findings reveal that hydrogen exhibits active directional migration with pronounced diffusion anisotropy, whereas helium passively aggregates in response. While the conventional mixing rule underestimates mutual diffusion coefficients by neglecting velocity cross-correlations,the assumption of an ideal thermodynamic factor(Q = 1) overestimates them due to unaccounted non-ideal thermodynamic effects—both particularly pronounced in strongly phase-separated regimes. Notably, hydrogen's dual role, anisotropic diffusion and bond stabilization via helium doping, modulates demixing kinetics. Large-scale simulations(216,000 atoms) propose novel phase-separation paradigms, such as “hydrogen bubble/wisp” formation, challenging the classical “helium rain” scenario, striving to bridge atomic-scale dynamics to planetary-scale phase evolution. 展开更多
关键词 molecular dynamics simulations gas giants helium diffusion h he systems hydrogen diffusion determine self mutual diffusion coefficients h he binary systems dynamics phase separation
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Investigating phase dynamics of materials under laser-induced extreme conditions
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作者 Liang Sun Bo Chen +4 位作者 Zhongjing Chen jiayu dai Wenge Yang Toshimori Sekine Ho-Kwang Mao 《Matter and Radiation at Extremes》 2025年第6期4-8,共5页
Shock compression driven by nanosecond-laser techniques generates extreme pressure and temperature conditions in materials,enabling the study of high-pressure phase transitions and the behavior of materials in extreme... Shock compression driven by nanosecond-laser techniques generates extreme pressure and temperature conditions in materials,enabling the study of high-pressure phase transitions and the behavior of materials in extreme environments.These dynamic high-pressure states are relevant to a wide range of phenomena,including planetary formation,asteroid impacts,spacecraft shielding,and inertial confinement fusion.The integration of advanced X-ray diffraction experimental techniques,from laser-induced X-ray sources and X-ray free-electron lasers,and theoretical simulations has provided unprecedented insights into material behavior under extreme conditions.This perspective reviews recent advances in dynamic high-pressure research and the insights that they can provide,concentrating on dynamical phase transitions,metastable and transient states,the influence of crystal orientation,microstructural changes,and the kinetic mechanism of phase transitions across a variety of interdisciplinary fields. 展开更多
关键词 high pressure phase transitions inertial confinement fusionthe planetary formationasteroid impactsspacecraft shieldingand laser induced extreme conditions nanosecond laser techniques shock compression material behavior planetary formation
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Anisotropic displacement threshold energy and defect distribution in diamond:PKA energy and temperature effect
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作者 Ke Wu Zeyi Du +8 位作者 Hongyang Liu Nanyun Bao Chengke Xu Hongrui Wang Qunchao Tong Bo Chen Dongdong Kang Guang Wang jiayu dai 《Chinese Physics B》 2025年第8期659-666,共8页
Diamond is a promising semiconductor material for future space exploration,owing to its unique atomic and electronic structures.However,diamond materials and related devices still suffer from irradiation damage under ... Diamond is a promising semiconductor material for future space exploration,owing to its unique atomic and electronic structures.However,diamond materials and related devices still suffer from irradiation damage under space irradiation involving high-energy irradiating particles.The study of the generation and evolution of point defects can help understand the irradiation damage mechanisms in diamond.This study systematically investigated the defect dynamics of diamond in 162 crystallographic directions uniformly selected on a spherical surface using molecular dynamics simulations,with primary knock-on atom(PKA)energies up to 20 keV,and temperatures ranging from 300 K to 1800 K.The results reveal that the displacement threshold energy of diamond changes periodically with crystallographic directions,which is related to the shape of potential energy surface along that direction.Additionally,the number of residual defects correlates positively with PKA energy.However,temperature has dual competing effects:while it enhances the probability of atomic displacement,it simultaneously suppresses the probability of defect formation by accelerating defect recombination.The calculation of sparse radial distribution function indicates that the defect distribution shows a certain degree of similarity in the short-range region across different PKA energies.As the PKA energy increases,defect clusters tend to become larger in size and more numerous in quantity.This study systematically investigates the anisotropy of displacement threshold energy and elucidates the relationship between various irradiation conditions and the final states of irradiation-induced defects. 展开更多
关键词 displacement cascades DIAMOND molecular dynamics temperature effect
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Carrier Relaxation Times in InAs/AlAs Superlattices:Modulating by Layers,Temperature,and Carrier Concentrations
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作者 Enrui Zhang Jinshan Yao +3 位作者 Zhiming Geng Yueying Hou jiayu dai Hong Lu 《Chinese Physics Letters》 2025年第2期271-275,共5页
InAs/AlAs superlattice structures have significant potential for application in low-noise avalanche photodetectors.With their performance in practical applications linked to the fundamental physical properties of carr... InAs/AlAs superlattice structures have significant potential for application in low-noise avalanche photodetectors.With their performance in practical applications linked to the fundamental physical properties of carrier relaxation time,this study investigated the carrier relaxation times of InAs/AlAs superlattices across various monolayers,temperatures,and carrier concentrations.Our investigation indicated that relaxation times span several tens of picoseconds,confirming that high-quality interfaces do not significantly reduce relaxation times in the way defect states might.Moreover,our study demonstrates that adjustments to the superlattice period can effectively modulate both the bandgap and carrier relaxation times,potentially impacting the performance of avalanche photodiodes by altering the electron-phonon interaction pathways and bandgap width.We established that lower temperatures contribute to an increase in the bandgap and the suppression of high-frequency optical phonon vibrations,thereby lengthening the relaxation times.Additionally,our observations indicate that in InAs/AlAs superlattices,the relaxation time increases as the excitation power increases,owing to the phonon bottleneck effect.These insights into InAs/AlAs superlattice carrier dynamics highlight their applicability in enhancing avalanche photodetectors,and may contribute to the optimized design of superlattices for specific applications. 展开更多
关键词 RELAXATION TIMES PHONON
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Lattice Thermal Conductivity of MgSiO_(3) Perovskite and Post-Perovskite under Lower Mantle Conditions Calculated by Deep Potential Molecular Dynamics 被引量:7
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作者 Fenghu Yang Qiyu Zeng +5 位作者 Bo Chen Dongdong Kang Shen Zhang Jianhua Wu Xiaoxiang Yu jiayu dai 《Chinese Physics Letters》 SCIE EI CAS CSCD 2022年第11期42-47,共6页
Lattice thermal conductivity(κlat)of MgSiO_(3) perovskite and post-perovskite is an important parameter for the thermal dynamics in the Earth.Here,we develop a deep potential of density functional theory quality unde... Lattice thermal conductivity(κlat)of MgSiO_(3) perovskite and post-perovskite is an important parameter for the thermal dynamics in the Earth.Here,we develop a deep potential of density functional theory quality under entire thermodynamic conditions in the lower mantle,and calculate theκlatby the Green-Kubo relation.Deep potential molecular dynamics captures full-order anharmonicity and considers ill-defined phonons in low-κlatmaterials ignored in the phonon gas model.Theκlatshows negative temperature dependence and positive linear pressure dependence.Interestingly,theκlatundergos an increase at the phase boundary from perovskite to post-perovskite.We demonstrate that,along the geotherm,theκlatincreases by 18.2% at the phase boundary.Our results would be helpful for evaluating Earth’s thermal dynamics and improving the Earth model. 展开更多
关键词 LATTICE PEROVSKITE DEEP
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Towards the Same Line of Liquid–Liquid Phase Transition of Dense Hydrogen from Various Theoretical Predictions 被引量:3
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作者 Binbin Lu Dongdong Kang +2 位作者 Dan Wang Tianyu Gao jiayu dai 《Chinese Physics Letters》 SCIE CAS CSCD 2019年第10期22-27,共6页
For a long time,there have been huge discrepancies between different models and experiments concerning the liquid-liquid phase transition(LLPT)in dense hydrogen.We present the results of extensive calculations of the ... For a long time,there have been huge discrepancies between different models and experiments concerning the liquid-liquid phase transition(LLPT)in dense hydrogen.We present the results of extensive calculations of the LLPT in dense hydrogen using the most expensive first-principle path-integral molecular dynamics simulations available.The nonlocal density functional rVV10 and the hybrid functional PBEO are used to improve the description of the electronic structure of hydrogen.Of all the density functional theory calculations available,we report the most consistent results through quantum Monte Carlo simulations and coupled electron-ion Monte Carlo simulations of the LLPT in dense hydrogen.The critical point of the first-order LLPT is estimated to be above 2000 K according to the equation of state.Moreover,the metallization pressure obtained from the jump of dc electrical conductivity almost coincides with the plateau of equation of state. 展开更多
关键词 state. EQUATION TRANSITION
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Strain‑Induced Surface Interface Dual Polarization Constructs PML‑Cu/Bi_(12)O_(17)Br_(2) High‑Density Active Sites for CO_(2) Photoreduction 被引量:1
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作者 Yi Zhang Fangyu Guo +6 位作者 Jun Di Keke Wang Molly Meng‑Jung Li jiayu dai Yuanbin She Jiexiang Xia Huaming Li 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第5期169-183,共15页
The insufficient active sites and slow interfacial charge trans-fer of photocatalysts restrict the efficiency of CO_(2) photoreduction.The synchronized modulation of the above key issues is demanding and chal-lenging.... The insufficient active sites and slow interfacial charge trans-fer of photocatalysts restrict the efficiency of CO_(2) photoreduction.The synchronized modulation of the above key issues is demanding and chal-lenging.Herein,strain-induced strategy is developed to construct the Bi–O-bonded interface in Cu porphyrin-based monoatomic layer(PML-Cu)and Bi_(12)O_(17)Br_(2)(BOB),which triggers the surface interface dual polarization of PML-Cu/BOB(PBOB).In this multi-step polarization,the built-in electric field formed between the interfaces induces the electron transfer from con-duction band(CB)of BOB to CB of PML-Cu and suppresses its reverse migration.Moreover,the surface polarization of PML-Cu further promotes the electron converge in Cu atoms.The introduction of PML-Cu endows a high density of dispersed Cu active sites on the surface of PBOB,significantly promoting the adsorption and activation of CO_(2) and CO desorption.The conversion rate of CO_(2) photoreduction to CO for PBOB can reach 584.3μmol g-1,which is 7.83 times higher than BOB and 20.01 times than PML-Cu.This work offers valuable insights into multi-step polarization regulation and active site design for catalysts. 展开更多
关键词 Bi_(12)O_(17)Br_(2) Porphyrin CO_(2)photoreduction Polarization Active sites
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On the thermodynamics of plasticity during quasi-isentropic compression of metallic glass 被引量:1
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作者 Kaiguo Chen Bo Chen +7 位作者 Yinan Cui Yuying Yu Jidong Yu Huayun Geng Dongdong Kang Jianhua Wu Yao Shen jiayu dai 《Matter and Radiation at Extremes》 SCIE EI CSCD 2024年第2期74-89,共16页
Entropy production in quasi-isentropic compression (QIC) is critically important for understanding the properties of materials under extremeconditions. However, the origin and accurate quantification of entropy in thi... Entropy production in quasi-isentropic compression (QIC) is critically important for understanding the properties of materials under extremeconditions. However, the origin and accurate quantification of entropy in this situation remain long-standing challenges. In this work, a framework is established for the quantification of entropy production and partition, and their relation to microstructural change in QIC. Cu50Zr50is taken as a model material, and its compression is simulated by molecular dynamics. On the basis of atomistic simulation-informed physicalproperties and free energy, the thermodynamic path is recovered, and the entropy production and its relation to microstructural change aresuccessfully quantified by the proposed framework. Contrary to intuition, entropy production during QIC of metallic glasses is relativelyinsensitive to the strain rate ˙γ when ˙γ ranges from 7.5 × 10^(8) to 2 × 10^(9)/s, which are values reachable in QIC experiments, with a magnitudeof the order of 10^(−2)kB/atom per GPa. However, when ˙γ is extremely high (>2 × 10^(9)/s), a notable increase in entropy production rate with˙γ is observed. The Taylor–Quinney factor is found to vary with strain but not with strain rate in the simulated regime. It is demonstrated thatentropy production is dominated by the configurational part, compared with the vibrational part. In the rate-insensitive regime, the increase inconfigurational entropy exhibits a linear relation to the Shannon-entropic quantification of microstructural change, and a stretched exponential relation to the Taylor–Quinney factor. The quantification of entropy is expected to provide thermodynamic insights into the fundamentalrelation between microstructure evolution and plastic dissipation. 展开更多
关键词 ENTROPY METALLIC REGIME
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Trunk‑Inspired SWCNT‑Based Wrinkled Films for Highly‑Stretchable Electromagnetic Interference Shielding and Wearable Thermotherapy
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作者 Xiaofeng Gong Tianjiao Hu +8 位作者 You Zhang Yanan Zeng Ye Zhang Zhenhua Jiang Yinlong Tan Yanhong Zou Jing Wang jiayu dai Zengyong Chu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第11期429-444,共16页
Nowadays,the increasing electromagnetic waves generated by wearable devices are becoming an emerging issue for human health,so stretchable electromagnetic interference(EMI)shielding materials are highly demanded.Eleph... Nowadays,the increasing electromagnetic waves generated by wearable devices are becoming an emerging issue for human health,so stretchable electromagnetic interference(EMI)shielding materials are highly demanded.Elephant trunks are capable of grabbing fragile vegetation and tearing trees thanks not only to their muscles but also to their folded skins.Inspired by the wrinkled skin of the elephant trunks,herein,we propose a winkled conductive film based on single-walled carbon nanotubes(SWCNTs)for multifunctional EMI applications.The conductive film has a sandwich structure,which was prepared by coating SWCNTs on both sides of the stretched elastic latex cylindrical substrate.The shrinking-induced winkled conductive network could withstand up to 200%tensile strain.Typically,when the stretching direction is parallel to the polarization direction of the electric field,the total EMI shielding effectiveness could surprisingly increase from 38.4 to 52.7 dB at 200%tensile strain.It is mainly contributed by the increased connection of the SWCNTs.In addition,the film also has good Joule heating performance at several voltages,capable of releasing pains in injured joints.This unique property makes it possible for strain-adjustable multifunctional EMI shielding and wearable thermotherapy applications. 展开更多
关键词 Electromagnetic interference shielding Single-walled carbon nanotubes WRINKLES STRETCHABLE THERMOTHERAPY
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Measurement and correlation of solubility of 9-fluorenone in 11 pure organic solvents from T = 283.15 to 323.15 K
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作者 Huiqi Wang Jianpo Ren +5 位作者 Shihao Zhang jiayu dai Yue Niu Ketao Shi Qiuxiang Yin Ling Zhou 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第8期235-241,共7页
In this work, the solubility data of 9-fluorenone in 11 pure solvents(methanol, ethanol, n-propanol, isopropanol, n-butanol, iso-butanol, acetonitrile, ethyl formate, ethyl acetate, dimethyl sulfoxide, n-hexane)were m... In this work, the solubility data of 9-fluorenone in 11 pure solvents(methanol, ethanol, n-propanol, isopropanol, n-butanol, iso-butanol, acetonitrile, ethyl formate, ethyl acetate, dimethyl sulfoxide, n-hexane)were measured by the gravimetric method from 278.15 K to 318.15 K under atmospheric pressure. The results showed that the solubility of 9-fluorenone in all tested solvents increased with the raised temperature. The solubility data were correlated by the modified Apelblat equation, λh model and NRTL(nonradom two fluid) model. The average relative deviation(ARD) correlated by three thermodynamic models in different solvents was all below 5%, which indicated that the three thermodynamic models fit the solubility data well. Furthermore, the mixing thermodynamic properties of 9-fluorenone in pure solvent systems were calculated via NRTL model. The results indicated the dissolution process of 9-fluorenone is spontaneous and entropically favorable. The solubility and the mixing thermodynamic properties provided in this paper would play an important role in industrial manufacture and follow-up operation of 9-fluorenone. 展开更多
关键词 9-Fluorenone SOLUBILITY Correlation model Thermodynamic properties
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Structural and Phase Engineering in Two-Dimensional Polymorphic In_(2)Se_(3)
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作者 Ming Yang Guang Wang +4 位作者 Bo Li Yayun Yu Bowen Yao Zhihui Qin jiayu dai 《Chinese Physics Letters》 2025年第12期239-252,共14页
The two-dimensional van der Waals layered semiconductor In_(2)Se_(3) has emerged as a promising candidate for non-volatile ferroelectric memory,optoelectronic devices,and polymorphic phase engineering.Polymorphic In_(... The two-dimensional van der Waals layered semiconductor In_(2)Se_(3) has emerged as a promising candidate for non-volatile ferroelectric memory,optoelectronic devices,and polymorphic phase engineering.Polymorphic In_(2)Se_(3) typically stabilizes in three distinct phases:α-,β′-,and β^(*)-In_(2)Se_(3),each dominant within specific temperature ranges.Although the crystal structures and ferroelectric properties of these phases have been widely studied,the unambiguous assignment of their in-plane and out-of-plane ferroelectric behaviors,as well as the mechanisms governing their phase transitions,remains a subject of active debate.In this study,we investigate the evolution of atomic and electronic structures in molecular beam epitaxy-grown ultrathin In_(2)Se_(3) films through correlated microstructural and macroscopic physical property analysis.By employing scanning tunneling microscopy/spectroscopy,temperature-dependent Raman spectroscopy,and piezoresponse force microscopy,we demonstrate a reversible temperature-induced phase transition between the in-plane ferroelectric β^(*)and antiferroelectric β′phases.Furthermore,we confirm robust out-of-plane ferroelectric polarization in the as-grown films and achieve an electric-field-driven transition from the β^(*)to β′phase.Our findings not only advance the fundamental understanding of phase transitions and polarization evolution in two-dimensional semiconductors but also open new avenues for the design of tunable,non-volatile ferroelectric memory devices. 展开更多
关键词 polymorphic phase engineeringpolymorphic structural engineering optoelectronic devices two dimensional polymorphic ferroelectric properties Se crystal structures phase engineering
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Three-step formation of diamonds in shock-compressed hydrocarbons:Dissociation,species separation,and nucleation
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作者 Bo Chen Qiyu Zeng +4 位作者 Xiaoxiang Yu Jiahao Chen Shen Zhang Dongdong Kang jiayu dai 《Matter and Radiation at Extremes》 2026年第1期58-67,共10页
The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have bee... The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets. 展开更多
关键词 diamond formation formation processes ice giant planetsspecies separation dissociation deep learning modelwe carbon hydrogen static shock compression experimentsneverthelessthe chemical evolution
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Green extraction of vanadium resources:A process for the preparation of vanadium oxide in an ammonia-free system
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作者 Xinyu Liu Yue Sun +4 位作者 Jing Wen Tao Jiang Lan Zhang Jinchao Yang jiayu dai 《Chinese Journal of Chemical Engineering》 2025年第12期265-273,共9页
The current vanadium extraction process from sodium roasted vanadium slag poses risks such as ammonia pollution.This study proposes a novel calcium-based vanadium extraction and hydrolysis precipitation process,achiev... The current vanadium extraction process from sodium roasted vanadium slag poses risks such as ammonia pollution.This study proposes a novel calcium-based vanadium extraction and hydrolysis precipitation process,achieving clean and efficient vanadium recovery.The introduction of Ca O facilitates the targeted reconstruction and conversion of vanadium and calcium in the solution,forming acidsoluble calcium vanadate intermediates.Under optimal conditions,n(Ca)/n(V)ratio of 1.75,extraction temperature of 90℃,and extraction time of 90 min,the vanadium extraction ratio reached 99.83%.This process also separates vanadium from sodium and silicon,enabling one-step purification of the vanadium solution.Subsequent sulfuric acid leaching,conducted at p H of 4.0,90℃,and 60 min,achieved a vanadium leaching ratio of 99.72%,further separating vanadium from calcium and other impurities.Finally,the purified vanadium solution underwent hydrolysis precipitation at p H of 2.1 and 95℃for60 min,achieving a precipitation ratio of 98.69%.The calcined product yielded V_(2)O_(5) with a purity of 98.60%.Compared to the conventional sodium roasting—water leaching along with ammonium salt precipitation process,this innovative method eliminates ammonia-nitrogen wastewater emissions.This study provides a foundation for the development of new vanadium extraction technologies from vanadium slag. 展开更多
关键词 Vanadium slag Sodium roasting Vanadium extraction by CaO Hydrolysis precipitation Vanadium pentoxide(V_(2)O_(5))
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Sequential phase transformations in Ta_(0.4)Ti_(2)Zr alloy via tensile molecular dynamics simulations with deep potential
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作者 Hongyang Liu Rong Chen +3 位作者 Bo Chen Jingzhi He Dongdong Kang jiayu dai 《Chinese Physics B》 2026年第1期46-55,共10页
Understanding the complex deformation mechanisms of non-equimolar multi-principal element alloys(MPEAs)requires high-fidelity atomic-scale simulations.This study develops a deep potential(DP)model to enable molecular ... Understanding the complex deformation mechanisms of non-equimolar multi-principal element alloys(MPEAs)requires high-fidelity atomic-scale simulations.This study develops a deep potential(DP)model to enable molecular dynamics simulations of the Ta_(0.4)Ti_(2)Zr(Ta_(0.4))alloy.Monte Carlo simulations using this potential reveal Ta atom precipitation in the Ta_(0.4)alloy.Under uniaxial tensile loading along the[100]direction in the NPT ensemble,the alloy undergoes a remarkable sequence of phase transformations:an initial body-centered cubic(BCC_(1))to face-centered cubic(FCC)transformation,followed by a reverse transformation from FCC to a distinct BCC phase(BCC_(2)),and finally a BCC_(2) to hexagonal close-packed(HCP)transformation.Critically,the reverse FCC to BCC_(2) transformation induces significant volume contraction.We demonstrate that the inversely transformed BCC_(2) phase primarily accommodates compressive stress.Concurrently,the reorientation of BCC_(2) crystals contributes substantially to the observed high strain hardening.These simulations provide atomic-scale insights into the dynamic structural evolution,sequential phase transformations,and stress partitioning during deformation of the Ta_(0.4)alloy.The developed DP model and the revealed mechanisms offer fundamental theoretical guidance for accelerating the design of high-performance MPEAs. 展开更多
关键词 multi-principal element alloys machine-learning potential phase transformation stress partitioning
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Structural transition dynamics of the formation of warm dense gold: From an atomic scale view 被引量:5
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作者 QiYu Zeng jiayu dai 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2020年第6期33-41,共9页
With the highly optimized embedded-atom-method(EAM)potential and electron-phonon coupling factor obtained from experimental data,the dynamics of the formation of warm dense gold and the nuclear response of gold foils ... With the highly optimized embedded-atom-method(EAM)potential and electron-phonon coupling factor obtained from experimental data,the dynamics of the formation of warm dense gold and the nuclear response of gold foils upon intense laser excitation were investigated using two-temperature molecular dynamics simulations.Considering laser energy densities ranging from 0.18 to 1.17 MJ/kg,we provide a microscopic picture of the formation of warm dense gold.A threshold(0.19 MJ/kg)for the laser energy density was determined,identifying two different melting mechanisms.For an energy density below 0.19 MJ/kg,the melting of the foil is controlled by the propagation of melt fronts from external surfaces,which results in heterogeneous melting on the time scale of hundreds of picoseconds.For an energy density above 0.19 MJ/kg,homogeneous nucleation and growth of liquid regions inside the foil play the leading role,and homogeneous melting occurs with several picoseconds.Compared with previous simulations and experimental measurements,the evaluated different threshold value indicates that the improvement in the electron heat capacity for the two-temperature model by including the kinetic information of electrons may predict better laser-matter interactions under such extreme non-equilibrium conditions. 展开更多
关键词 molecular dynamics numerical methods solid-liquid transitions laser ablation of solids
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Tracking and recognition algorithm for a robot harvesting oscillating apples 被引量:3
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作者 Qinghua Yang Chen Chen +2 位作者 jiayu dai Yi Xun Guanjun Bao 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2020年第5期163-170,共8页
Apple fruits on trees tend to swing because of wind or other natural causes,therefore reducing the accuracy of apple picking by robots.To increase the accuracy and to speed up the apple tracking and identifying proces... Apple fruits on trees tend to swing because of wind or other natural causes,therefore reducing the accuracy of apple picking by robots.To increase the accuracy and to speed up the apple tracking and identifying process,tracking and recognition method combined with an affine transformation was proposed.The method can be divided into three steps.First,the initial image was segmented by Otsu’s thresholding method based on the two times Red minus Green minus Blue(2R-G-B)color feature;after improving the binary image,the apples were recognized with a local parameter adaptive Hough circle transformation method,thus improving the accuracy of recognition and avoiding the long,time-consuming process and excessive fitted circles in traditional Hough circle transformation.The process and results were verified experimentally.Second,the Shi-Tomasi corners detected and extracted from the first frame image were tracked,and the corners with large positive and negative optical flow errors were removed.The affine transformation matrix between the two frames was calculated based on the Random Sampling Consistency algorithm(RANSAC)to correct the scale of the template image and predict the apple positions.Third,the best positions of the target apples within 1.2 times of the prediction area were searched with a de-mean normalized cross-correlation template matching algorithm.The test results showed that the running time of each frame was 25 ms and 130 ms and the tracking error was more than 8%and 20%in the absence of template correction and apple position prediction,respectively.In comparison,the running time of our algorithm was 25 ms,and the tracking error was less than 4%.Therefore,test results indicate that speed and efficiency can be greatly improved by using our method,and this strategy can also provide a reference for tracking and recognizing other oscillatory fruits. 展开更多
关键词 apple picking robot tracking and recognition algorithm oscillating apple Hough transform pyramid LK optical flow algorithm affine transform template matching
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Full-scale ab initio simulations of laser-driven atomistic dynamics 被引量:4
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作者 Qiyu Zeng Bo Chen +4 位作者 Shen Zhang Dongdong Kang Han Wang Xiaoxiang Yu jiayu dai 《npj Computational Materials》 SCIE EI CSCD 2023年第1期190-196,共7页
The coupling of excited states and ionic dynamics is the basic and challenging point for the materials response at extreme conditions.In the laboratory,the intense laser produces transient nature and complexity with h... The coupling of excited states and ionic dynamics is the basic and challenging point for the materials response at extreme conditions.In the laboratory,the intense laser produces transient nature and complexity with highly nonequilibrium states,making it extremely difficult and interesting for both experimental measurements and theoretical methods.With the inclusion of laser-excited states,we extend an ab initio method into the direct simulations of whole laser-driven microscopic dynamics from solid to liquid.We construct the framework of combining the electron-temperature-dependent deep neural-network potential energy surface with a hybrid atomistic-continuum approach,controlling non-adiabatic energy exchange and atomistic dynamics,which enables consistent interpretation of experimental data.By large-scale ab initio simulations,we demonstrate that the nonthermal effects introduced by hot electrons play a dominant role in modulating the lattice dynamics,thermodynamic pathway,and structural transformation.We highlight that the present work provides a path to realistic computational studies of laser-driven processes,thus bridging the gap between experiments and simulations. 展开更多
关键词 DYNAMICS EXCITED BRIDGING
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Light-induced irreversible structural phase transition in trilayer graphene 被引量:3
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作者 Jianyu Zhang Jinsen Han +13 位作者 Gang Peng Xi Yang Xiaoming Yuan Yongjun Li Jianing Chen Wei Xu Ken Liu Zhihong Zhu Weiqi Cao Zheng Han jiayu dai Mengjian Zhu Shiqiao Qin Kostya S.Novoselov 《Light: Science & Applications》 SCIE EI CAS CSCD 2020年第1期335-345,共11页
A crystal structure has a profound influence on the physical properties of the corresponding material.By synthesizing crystals with particular symmetries,one can strongly tune their properties,even for the same chemic... A crystal structure has a profound influence on the physical properties of the corresponding material.By synthesizing crystals with particular symmetries,one can strongly tune their properties,even for the same chemical configuration(compare graphite and diamond,for instance).Even more interesting opportunities arise when the structural phases of crystals can be changed dynamically through external stimulations.Such abilities,though rare,lead to a number of exciting phenomena,such as phase-change memory effects.In the case of trilayer graphene,there are two common stacking configurations(ABA and ABC)that have distinct electronic band structures and exhibit very different behaviors.Domain walls exist in the trilayer graphene with both stacking orders,showing fascinating new physics such as the quantum valley Hall effect.Extensive efforts have been dedicated to the phase engineering of trilayer graphene.However,the manipulation of domain walls to achieve precise control of local structures and properties remains a considerable challenge.Here,we experimentally demonstrate that we can switch from one structural phase to another by laser irradiation,creating domains of different shapes in trilayer graphene.The ability to control the position and orientation of the domain walls leads to fine control of the local structural phases and properties of graphene,offering a simple but effective approach to create artificial two-dimensional materials with designed atomic structures and electronic and optical properties. 展开更多
关键词 STRUCTURAL walls PHASE
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Dynamic landscape mapping of humoral immunity to SARS-CoY-2 identifies non-structural protein antibodies associated with the survival of critical COVID-19 patients 被引量:2
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作者 Linlin Cheng Xiaomei Zhang +27 位作者 Yu Chen Dan Wang Dong Zhang Songxin Yan Hongye Wang Meng Xiao Te Liang Haolong Li Meng Xu Xin Hou jiayu dai Xian Wu Mingyuan Li Minya Lu Dong Wu Ran Tian Jing Zhao Yan Zhang Wei Cao Jinglan Wang Xiaowei Yan Xiang Zhou Zhengyin Liu Yingchun Xu Fuchu He Yongzhe Li Xiaobo Yu Shuyang Zhang 《Signal Transduction and Targeted Therapy》 SCIE CSCD 2021年第9期2843-2856,共14页
A comprehensive analysis of the humoral immune response to the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is essential in understanding COVID-19 pathogenesis and developing antibody-based diagnostics a... A comprehensive analysis of the humoral immune response to the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is essential in understanding COVID-19 pathogenesis and developing antibody-based diagnostics and therapy.In this work,we performed a longitudinal analysis of antibody responses to SARS-CoV-2 proteins in 104 serum samples from 49 critical COVID-19 patients using a peptide-based SARS-CoV-2 proteome microarray.Our data show that the binding epitopes of IgM and IgG antibodies differ across SARS-CoV-2 proteins and even within the same protein. 展开更多
关键词 IMMUNITY ANTIBODIES PATIENTS
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High-speed and low-power molecular dynamics processing unit(MDPU)with ab initio accuracy 被引量:2
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作者 Pinghui Mo Yujia Zhang +21 位作者 Zhuoying Zhao Hanhan Sun Junhua Li Dawei Guan Xi Ding Xin Zhang Bo Chen Mengchao Shi Duo Zhang Denghui Lu Yinan Wang Jianxing Huang Fei Liu Xinyu Li Mohan Chen Jun Cheng Bin Liang Weinan E jiayu dai Linfeng Zhang Han Wang Jie Liu 《npj Computational Materials》 CSCD 2024年第1期559-568,共10页
Molecular dynamics(MD)is an indispensable atomistic-scale computational tool widely-used in various disciplines.In the past decades,nearly all ab initio MD and machine-learning MD have been based on the general-purpos... Molecular dynamics(MD)is an indispensable atomistic-scale computational tool widely-used in various disciplines.In the past decades,nearly all ab initio MD and machine-learning MD have been based on the general-purpose central/graphics processing units(CPU/GPU),which are well-known to suffer from their intrinsic“memory wall”and“power wall”bottlenecks.Consequently,nowadays MD calculations with ab initio accuracy are extremely time-consuming and power-consuming,imposing serious restrictions on the MD simulation size and duration.To solve this problem,here we propose a special-purpose MD processing unit(MDPU),which could reduce MD time and power consumption by about 103 times(109 times)compared to state-of-the-art machine-learningMD(ab initio MD)based on CPU/GPU,while keeping ab initio accuracy.With significantly-enhanced performance,the proposed MDPU may pave a way for the accurate atomistic-scale analysis of large-size and/or longduration problems which were impossible/impractical to compute before. 展开更多
关键词 consuming power MDP
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