This paper addresses the issue of reciprocating compressors staggered labyrinth seal structure. The internal flow field of sealed structure, the displacement of cylinder and piston for different tooth profile angles a...This paper addresses the issue of reciprocating compressors staggered labyrinth seal structure. The internal flow field of sealed structure, the displacement of cylinder and piston for different tooth profile angles are analyzed synchronously using FLUENT software, and the effects of fluid-structure interaction on the performance of the labyrinth seal are revealed. The results indicate that with the growth of tooth profile angle, the leakage rate of labyrinth seal tends to decrease first, and then increase. The results of fluid-structure interaction analysis are close to those of actual engineering. The effect of fluid-structure interaction makes tiny deformation in calculation mesh of piston and cylinder structure, and the coupling interaction affects the performance of the labyrinth seal.展开更多
The shear stress field proximity to the twinning and prismatic/basal interfaces of {1012} tensile twins is shown by molecular dynamics simulations.The stress field interacts and influences the twinning growth mode in ...The shear stress field proximity to the twinning and prismatic/basal interfaces of {1012} tensile twins is shown by molecular dynamics simulations.The stress field interacts and influences the twinning growth mode in the subsequent deformation process,which is simulated by changing the relative positions of the nuclei.An asymmetrical growth mode appears,in which the growth of one twin is predominant over the other when they are oriented at 45° to each other.This growth mode is sensitive to the simulation temperature and strain rate and can be attributed to the interaction of the stress field proximity to the prismatic/basal interfaces and twinning planes.展开更多
Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform mag- netic field and the Dzyaloshinski-Moriya interaction are included. We find that the nonuniform magnetic field a...Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform mag- netic field and the Dzyaloshinski-Moriya interaction are included. We find that the nonuniform magnetic field and Dzyaloshinski-Moriya interaction are the more efficient control parameters for the increase of entanglement and critical temperature. For both the nearest neighbour sites and the next nearest neighbour sites, the magnetic field can induce entanglement to a certain extent and the Dzyaloshinski-Moriya interaction can enhance the entanglement to a stable value. The steady value of the nearest neighbour site entanglement C12 is larger than the next nearest neighbour site entanglement C13. An interesting phenomenon is that the entanglement curve of C12 appears a peak value when the Dzyaloshinski-Moriya interaction is considered in a nonuniform magnetic field.展开更多
To improve current understanding of the water cycle,energy partitioning and CO2 exchange over hilly zone vegetative land surfaces in the subtropical monsoon environment of southern China,a long-term field experiment o...To improve current understanding of the water cycle,energy partitioning and CO2 exchange over hilly zone vegetative land surfaces in the subtropical monsoon environment of southern China,a long-term field experiment observatory was set up at Ningxiang,eastern Hunan Province.This paper presents a preliminary analysis of the field observations at the observatory collected from August to November 2012.Results show that significant diurnal variations in soil temperature occur only in shallow soil layers(0.05,0.10,and 0.20 m),and that heavy rainfall affects soil moisture in the deep layers(≥ 0.40 m).During the experimental period,significant diurnal variations in albedo,radiation components,energy components,and CO2 flux were observed,but little seasonal variation.Strong photosynthesis in the vegetation canopy enhanced the CO2 absorption and the latent heat released in daylight hours;Latent heat of evaporation was the main consumer of available energy in late summer.Because the field experiment data are demonstrably reliable,the observatory will provide reliable long-term measurements for future investigations of the land-atmosphere interaction over hilly land surfaces in the subtropical monsoon region of southern China.展开更多
A three-dimensional four species multi-fluid magnetohydrodynamic (MHD) model was constructed to simulate the solar wind global interaction with Mars. The model was augmented to consider production and loss of the sign...A three-dimensional four species multi-fluid magnetohydrodynamic (MHD) model was constructed to simulate the solar wind global interaction with Mars. The model was augmented to consider production and loss of the significant ion species in the Martian ionosphere, i.e., H^+, O2^+, O^+, CO^+2, associated with chemical reactions among all species. An ideal dipole-like local crustal field model was used to simplify the empirically measured Martian crustal field. Results of this simulation suggest that the magnetic pile-up region (MPR) and the velocity profile in the meridian plane are asymmetric, which is due to the nature of the multi-fluid model to decouple individual ion velocity resulting in occurrence of plume flow in the northern Martian magnetotail. In the presence of dipole magnetic field model, boundary layers, such as bow shock (BS) and magnetic pile-up boundary (MPB), become protuberant. Moreover, the crustal field has an inhibiting effect on the flux of ions escaping from Mars, an effect that occurs primarily in the region between the terminator (SZA 90°) and the Sun Mars line of the magnetotail (SZA 180°), partially around the terminator region. In contrast, near the tailward central line the crustal field has no significant impact on the escaping flux.展开更多
Three-dimensional holographic vector of atomic interaction field（3D-HoVAIF） is used to describe the chemical structures of polychlorinated naphthalenes（PCNs）.After variable screening by stepwise multiple regressio...Three-dimensional holographic vector of atomic interaction field（3D-HoVAIF） is used to describe the chemical structures of polychlorinated naphthalenes（PCNs）.After variable screening by stepwise multiple regression（SMR） technique,the liner relationships between gas-chromatographic relative retention time（RRT）,298 K supercooled liquid pressures（logPL）,n-octanol/air partition coefficient（logKOA）,n-octanol/water partition coefficient（logKOW）,aqueous solubilities（logSW）,relative in vitro potency values（-logEROD） of PCNs and 3D-HoVAIF descriptors have been established by partial least-square（PLS） regression.The result shows that the 3D-HoVAIF descriptors can be well used to express the quantitative structure-property（activity） relationships of PCNs.Predictive capability of the models has also been demonstrated by leave-one-out cross-validation.Moreover,the predicted values have been presented for those PCNs which are lack of experimentally physico-chemical properties and biological activity by the optimum models.展开更多
We examined the influences of the wind fi eld and wave-current interaction(WCI)on the numerical simulation results of typhoon-induced wind waves in the northern East China Sea(NECS)using the coupled Simulating Waves N...We examined the influences of the wind fi eld and wave-current interaction(WCI)on the numerical simulation results of typhoon-induced wind waves in the northern East China Sea(NECS)using the coupled Simulating Waves Nearshore+Advanced Circulation(SWAN+ADCIRC)model.The simulations were performed during two typhoon events(Lekima and Muifa),and two widely used reanalysis wind fields,the Climate Forecast System Version 2(CFSv2)from the National Centers for Environmental Prediction(NCEP)and the fifth-generation European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis(ERA5),were compared.The results indicate that the ERA5 and CFSv2 wind fields both reliably reproduced the wind variations measured by in-situ buoys,and the accuracy of the winds from ERA5 were generally better than those from CFSv2 because CFSv2 tended to overestimate the wind speed and the simulated significant wave height(SWH),particularly the peak SWH.The WCI effects between the two wind field simulations were similar;these effects enhanced the SWH throughout the nearshore NECS during both typhoons but suppressed the SWH on the right side of the Typhoon Muifa track in the deep and off shore sea areas.In summary,variations in the water depth and current propagation direction dominate the modulation of wave height.展开更多
Study on the quantitative structure-activity relationship （QSAR） of 26 compounds, N-[5-（2-furanyl）-2-methyl-4-oxo-4H-thieno[2,3-d]pyrimidin-3-yl]-carboxamide and 3-substituted- 5-（2-furanyl）-2-methyl-3H-thieno[2...Study on the quantitative structure-activity relationship （QSAR） of 26 compounds, N-[5-（2-furanyl）-2-methyl-4-oxo-4H-thieno[2,3-d]pyrimidin-3-yl]-carboxamide and 3-substituted- 5-（2-furanyl）-2-methyl-3H-thieno[2,3-d]pyrimidin-4-ones, with three-dimensional holographic vector of atomic interaction field （3D-HoVAIF） was carried out. SMR-PLS QSAR models have been created and good correlation coefficients and cross-validated correlation coefficients were obtained. The result shows that the models have good prediction capability and favorable stability and the 3D-HoVAIF is applicable to the molecular structural characterization and biological activity prediction.展开更多
Heterojunction photocatalysts have shown considerable activities for organic pollutants degradation.However,the faint connection interface and inferior charge shift efficiency critically block the property of heteroju...Heterojunction photocatalysts have shown considerable activities for organic pollutants degradation.However,the faint connection interface and inferior charge shift efficiency critically block the property of heterojunction photocatalysis.Herein,Bi_(2)O_(2)S/NiFe_(2)O_(4) nanosheets heterojunction with ultrastrong inter-face interaction and high internal electric field are designed by an in-situ growth method.Tentative and theoretical consequences prove that the interfacial interaction and internal electric field not only act as the electron flow bridge but also decrease the electrons shift energy obstacle,thus speeding up electrons transfer and achieving effective spatial electron-hole separation.Therefore,a large amount of·O_(2)^(-)and holes as active species were generated.Remarkably,Bi_(2)O_(2) S/NiFe_(2)O_(4) establishes a considerably boosted photocatalytic performance for tetracycline degradation(0.032 min^(-1)),which is about 14.2-fold and 7.8-fold of the pristine BOS and NFO,respectively.This work provides a promising motivation for modulating charge transfer by interface control and internal electric field to boost photocatalytic performance.展开更多
We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-ly...We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-lying excited states to the 1s-muon state can lead to the production of electron-positron pairs.We show that the Breit interaction determines the transition probabilities for states with nonzero orbital momentum.We show that the pair production arises mainly from the decay of the 2p states.Thus,the Breit interaction governs electron-positron pair production in bound-bound muon transitions.This process offers a unique opportunity to explore quantum electrodynamics in strong fields,as well as a class of nonradiative transitions involving electron-positron pair production.展开更多
This paper theoretically investigates the effects of crystal field and exchange interaction field on magnetic properties in dysprosium gallium garnet under extreme conditions （low temperatures and high magnetic field...This paper theoretically investigates the effects of crystal field and exchange interaction field on magnetic properties in dysprosium gallium garnet under extreme conditions （low temperatures and high magnetic fields） based on quantum theory. Here, five sets of crystal field parameters are discussed and compared. It demonstrates that, only considering the crystal field effect, the experiments can not be successfully explained. Thus, referring to the molecular field theory, an effective exchange field associated with the Dy-Dy exchange interaction is further taken into account. Under special consideration of crystal field and the exchange interaction field, it obtains an excellent agreement between the theoretical results and experiments, and further confirms that the exchange interaction field between rare-earth ions has great importance to magnetic properties in paramagnetic rare-earth gallium garnets.展开更多
Clarifying the gas ingestion mechanism in the turbine disc cavity of marine gas turbines is crucial for ensuring the normal operation of turbines.However, the ingestion is influenced by factors such as the rotational ...Clarifying the gas ingestion mechanism in the turbine disc cavity of marine gas turbines is crucial for ensuring the normal operation of turbines.However, the ingestion is influenced by factors such as the rotational pumping effect, mainstream pressure asymmetry, rotor–stator interaction,and unsteady flow structures, complicating the flow. To investigate the impact of rotor–stator interaction on ingestion, this paper decouples the model to include only the mainstream. This research employs experiments and numerical simulations to examine the effects of varying the flow coefficient through changes in rotational speed and mainstream flow rate. The main objective is to understand the influence of different rotor–stator interactions on the mainstream pressure field, accompanied by mechanistic explanations. The findings reveal inconsistent effects of the two methods for changing the flow coefficient on the mainstream pressure field. Particularly, the pressure distribution on the vane side primarily depends on the mainstream flow rate, while the pressure on the blade side is influenced by the mainstream flow rate and the attack angle represented by the flow coefficient. A larger angle of attack angle can increase pressure on the blade side, even surpassing the pressure on the vane side. Assessing the degree of mainstream pressure unevenness solely based on the pressure difference on the vane side is insufficient. This research provides a basis for subsequent studies on the influence of coupled real turbine rotor–stator interaction on gas ingestion.展开更多
A proposal is presented for teleporting Schr*iding-cat states. The process of the teleportation is achieved through the dispersive atom-cavity-field interaction. In this proposal, only measurement on the cavity field ...A proposal is presented for teleporting Schr*iding-cat states. The process of the teleportation is achieved through the dispersive atom-cavity-field interaction. In this proposal, only measurement on the cavity field and on the singlet atomic states are used.展开更多
The resonance interaction of two-state atoms with single mode field is described theoretically by using the semi-classical theory and Jaynes-Cummings model. The nonlinear characteristics of this system are calculated ...The resonance interaction of two-state atoms with single mode field is described theoretically by using the semi-classical theory and Jaynes-Cummings model. The nonlinear characteristics of this system are calculated by using FFT and Runge-Kutta methods. The chaotic strange attractors in this system are obtained from the numerical results.展开更多
A series of magnetic properties of Tm_2Fe_(14)B are explained quantitatively by the calculations based on the single ion model. The magnetic properties include the temperature dependence of the spontaneous magnetizati...A series of magnetic properties of Tm_2Fe_(14)B are explained quantitatively by the calculations based on the single ion model. The magnetic properties include the temperature dependence of the spontaneous magnetization, the spin reorientation temperature and the magnetization curves along the principal crystal axes at 4.2, 100, 150 and 200 K. The values of the exchange field and the crystalline electric field parameters used in the calculations are μ_BH_(ex)(T=0 K)=135, B_2~0=1.77, B_2~2=±2.97, B_4~0=-3.06×10^(-3), B_4^(-2)=0, B_4~4=-6.82×10^(-3), B_6~0=1.05× 10^(-5), B_6^(-2)=±7.40×10^(-5), B_6~4=1.96×10^(-4), and B_6^(-6)=0 all in K unit. The magnetization processes of the Fe-and Tm-sublattices at different temperatures are analysed. The processes are characterized by the non-collinearity between the magnetic moments of the Fe-and Tm-sublattices.展开更多
The interaction problem among fractures under the action of compressional stress is studied in this paper by using the finite element method and boundary element method respectively.The mechanical criteria which diffe...The interaction problem among fractures under the action of compressional stress is studied in this paper by using the finite element method and boundary element method respectively.The mechanical criteria which differentiate between the independent fractures and fracture systems and their computation methods are presented in this paper.The proportional conditions between length and spacing of fractures that exist interaction for several kinds of fracture groups of different geometric arrangement are given.The effect of interaction among fractures on the displacement field,stress field and strain energy distribution are computed.The relations between the fracture system of conjugate array and conjugate earthquakes are also discussed in this paper.展开更多
The effects of the Dzyaloshinski-Moriya （DM） interaction on the ground-state properties of the anisotropic XY chain in a transverse field have been studied by means of correlation functions and entanglement. Differe...The effects of the Dzyaloshinski-Moriya （DM） interaction on the ground-state properties of the anisotropic XY chain in a transverse field have been studied by means of correlation functions and entanglement. Different from the case without the DM interaction, the excitation spectra ek of this model are not symmetrical in the momentum space and are not always positive. As a result, besides the ferromagnetic （FM） and the paramagnetic （PM） phases, a gapless chiral phase is induced. In the chiral phase, the von Neumann entropy is proportional to log2 L （L is the length of a subchain） with the coefficient A ~ 1/3, which is the same as that of the XY chain in a transverse field without the DM interaction for 7 = 0 and 0 〈 h 〈 1. And in the vicinity of the critical point between the chiral phase and the FM （or PM） phase, the behaviors of the nearest- neighbor concurrence and its derivative are like those for the anisotropy transition.展开更多
There have been intensive studies on Kitaev materials for the sake of realization of exotic states such as quantum spin liquid and topological orders.In realistic materials,the Kitaev interaction may coexist with the ...There have been intensive studies on Kitaev materials for the sake of realization of exotic states such as quantum spin liquid and topological orders.In realistic materials,the Kitaev interaction may coexist with the Dzyaloshinskii–Moriya interaction,and it is of challenge to distinguish their magnitudes separately.Here,we study the topological magnon excitations and related thermal Hall conductivity of kagome magnet exhibiting Heisenberg,Kitaev and Dzyaloshinskii–Moriya interactions exposed to a magnetic field.In a strong magnetic field perpendicular to the plane of the lattice([111]direction)that brings the system into a fully polarized paramagnetic phase,we find that the magnon bands carry nontrivial Chern numbers in the full region of the phase diagram.Furthermore,there are phase transitions related to two topological phases with opposite Chern numbers,which lead to the sign changes of the thermal Hall conductivity.In the phase with negative thermal conductivity,the Kitaev interaction is relatively large and the width of the phase increases with the strength of Dzyaloshinskii–Moriya interaction.Hence,the present study will contribute to the understanding of related compounds.展开更多
We study electronic transport through a quantum dot （QD） with a precessing magnetic field. By using the Keldysh nonequilibrium Green function method, formulas of local density of states （LDOS） and conductance of Q...We study electronic transport through a quantum dot （QD） with a precessing magnetic field. By using the Keldysh nonequilibrium Green function method, formulas of local density of states （LDOS） and conductance of QD are derived self-consistently. It shows that the LDOS and conductance have obvious changes with the Coulomb blockade interaction. The intensity and angle of the magnetic field or temperatures, which reflect the mesoscopic structure of the QD are derived. The superiority of this device is that the QD can be controlled easily by the magnetic field, so it is valuable to apply in generating, manipulating and probing spin state.展开更多
We investigate the effects of pure Dzyaloshinskii Moriya （DM） interaction with magnetic field on entanglement in intrinsic decoherence, assuming that the system is initially in four Bell states ｜φ±〉 = （｜00...We investigate the effects of pure Dzyaloshinskii Moriya （DM） interaction with magnetic field on entanglement in intrinsic decoherence, assuming that the system is initially in four Bell states ｜φ±〉 = （｜00） ± ｜11〉）/√2 and ｜ψ±〉 = （｜01） ±｜10〉）/√2, respectively. It is found that if the system is initially in the state p1（0） = ｜φ＋〉〈φ＋1, the entanglement can obtain its maximum when the DM interaction vector D is in the plane of XOZ and magnetic field B = By with the infinite time t, moreover the entanglement is independent of By and t when By is perpendicular to D. In addition, we obtain similar results when the system is initially in the states p2（0） = ｜φ-〉〈φ-｜ or p3 （0） = ｜ψ＋〉〈ψ＋1. However, we find that if the system is initially in the state P4 （0） = ｜ψ-〉〈ψ-l, the entanglement can obtain its maximum for infinite t, when the DM vector is in the plane ofYOZ, XOZ, or XOY, with the magnetic field parallel to X, Y, or Z axis, respectively. Moreover, when the axial B is perpendicular to D for the initial state p4（O）, the negativity oscillates with time t and reaches a stable value, the larger the value of B is, the greater the stable value is, and the shorter the oscillation time of the negativity is. Thus we can adjust the direction and value of the external magnetic field to obtain the maximal entanglement, and avoid the adverse effects of external environment in some initial state. This is feasible within the cun＇ent experimental technology.展开更多
基金the Science and Technology Projects of Liaoning Province(No.2012219020)the China Postdoctoral Science Foundation(No.2013M541249)
文摘This paper addresses the issue of reciprocating compressors staggered labyrinth seal structure. The internal flow field of sealed structure, the displacement of cylinder and piston for different tooth profile angles are analyzed synchronously using FLUENT software, and the effects of fluid-structure interaction on the performance of the labyrinth seal are revealed. The results indicate that with the growth of tooth profile angle, the leakage rate of labyrinth seal tends to decrease first, and then increase. The results of fluid-structure interaction analysis are close to those of actual engineering. The effect of fluid-structure interaction makes tiny deformation in calculation mesh of piston and cylinder structure, and the coupling interaction affects the performance of the labyrinth seal.
基金financially supported by the National Natural Science Foundation of China(No.51301094)
文摘The shear stress field proximity to the twinning and prismatic/basal interfaces of {1012} tensile twins is shown by molecular dynamics simulations.The stress field interacts and influences the twinning growth mode in the subsequent deformation process,which is simulated by changing the relative positions of the nuclei.An asymmetrical growth mode appears,in which the growth of one twin is predominant over the other when they are oriented at 45° to each other.This growth mode is sensitive to the simulation temperature and strain rate and can be attributed to the interaction of the stress field proximity to the prismatic/basal interfaces and twinning planes.
文摘Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform mag- netic field and the Dzyaloshinski-Moriya interaction are included. We find that the nonuniform magnetic field and Dzyaloshinski-Moriya interaction are the more efficient control parameters for the increase of entanglement and critical temperature. For both the nearest neighbour sites and the next nearest neighbour sites, the magnetic field can induce entanglement to a certain extent and the Dzyaloshinski-Moriya interaction can enhance the entanglement to a stable value. The steady value of the nearest neighbour site entanglement C12 is larger than the next nearest neighbour site entanglement C13. An interesting phenomenon is that the entanglement curve of C12 appears a peak value when the Dzyaloshinski-Moriya interaction is considered in a nonuniform magnetic field.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA05110102)the National Natural Science Foundation of China (Grant No.41075062)the National Basic Research Program of China (Grant No. 2010CB951001)
文摘To improve current understanding of the water cycle,energy partitioning and CO2 exchange over hilly zone vegetative land surfaces in the subtropical monsoon environment of southern China,a long-term field experiment observatory was set up at Ningxiang,eastern Hunan Province.This paper presents a preliminary analysis of the field observations at the observatory collected from August to November 2012.Results show that significant diurnal variations in soil temperature occur only in shallow soil layers(0.05,0.10,and 0.20 m),and that heavy rainfall affects soil moisture in the deep layers(≥ 0.40 m).During the experimental period,significant diurnal variations in albedo,radiation components,energy components,and CO2 flux were observed,but little seasonal variation.Strong photosynthesis in the vegetation canopy enhanced the CO2 absorption and the latent heat released in daylight hours;Latent heat of evaporation was the main consumer of available energy in late summer.Because the field experiment data are demonstrably reliable,the observatory will provide reliable long-term measurements for future investigations of the land-atmosphere interaction over hilly land surfaces in the subtropical monsoon region of southern China.
基金supported by the pre-research projects on Civil Aerospace Technologies No.D020103 and D020105 funded by China’s National Space Administration (CNSA)support from the National Natural Science Foundation of China (NSFC) under grants 41674176, 41525015, 41774186, 41574156, and 41941001
文摘A three-dimensional four species multi-fluid magnetohydrodynamic (MHD) model was constructed to simulate the solar wind global interaction with Mars. The model was augmented to consider production and loss of the significant ion species in the Martian ionosphere, i.e., H^+, O2^+, O^+, CO^+2, associated with chemical reactions among all species. An ideal dipole-like local crustal field model was used to simplify the empirically measured Martian crustal field. Results of this simulation suggest that the magnetic pile-up region (MPR) and the velocity profile in the meridian plane are asymmetric, which is due to the nature of the multi-fluid model to decouple individual ion velocity resulting in occurrence of plume flow in the northern Martian magnetotail. In the presence of dipole magnetic field model, boundary layers, such as bow shock (BS) and magnetic pile-up boundary (MPB), become protuberant. Moreover, the crustal field has an inhibiting effect on the flux of ions escaping from Mars, an effect that occurs primarily in the region between the terminator (SZA 90°) and the Sun Mars line of the magnetotail (SZA 180°), partially around the terminator region. In contrast, near the tailward central line the crustal field has no significant impact on the escaping flux.
基金supported by the Ministry of Science and Technology of China (2010DFA32680)the National Natural Science Foundation of China (21005062)the Fundamental Research Funds for the Central Universities (CDJRC10220010)
文摘Three-dimensional holographic vector of atomic interaction field（3D-HoVAIF） is used to describe the chemical structures of polychlorinated naphthalenes（PCNs）.After variable screening by stepwise multiple regression（SMR） technique,the liner relationships between gas-chromatographic relative retention time（RRT）,298 K supercooled liquid pressures（logPL）,n-octanol/air partition coefficient（logKOA）,n-octanol/water partition coefficient（logKOW）,aqueous solubilities（logSW）,relative in vitro potency values（-logEROD） of PCNs and 3D-HoVAIF descriptors have been established by partial least-square（PLS） regression.The result shows that the 3D-HoVAIF descriptors can be well used to express the quantitative structure-property（activity） relationships of PCNs.Predictive capability of the models has also been demonstrated by leave-one-out cross-validation.Moreover,the predicted values have been presented for those PCNs which are lack of experimentally physico-chemical properties and biological activity by the optimum models.
基金Supported by the National Natural Science Foundation of China(Nos.U1706216,41976010,42006027,U1806227)the Natural Science Foundation of Shandong Province,China(No.ZR2016DQ16)+2 种基金the Key Deployment Project of Center for Ocean Mega-Science,Chinese Academy of Sciences(Nos.COMS2019J02,COMS2019J05)the Chinese Academy of Sciences Strategic Priority Project(Nos.XDA19060202,XDA19060502)the National Key Research and Development Program of China(No.2016YFC1402000)。
文摘We examined the influences of the wind fi eld and wave-current interaction(WCI)on the numerical simulation results of typhoon-induced wind waves in the northern East China Sea(NECS)using the coupled Simulating Waves Nearshore+Advanced Circulation(SWAN+ADCIRC)model.The simulations were performed during two typhoon events(Lekima and Muifa),and two widely used reanalysis wind fields,the Climate Forecast System Version 2(CFSv2)from the National Centers for Environmental Prediction(NCEP)and the fifth-generation European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis(ERA5),were compared.The results indicate that the ERA5 and CFSv2 wind fields both reliably reproduced the wind variations measured by in-situ buoys,and the accuracy of the winds from ERA5 were generally better than those from CFSv2 because CFSv2 tended to overestimate the wind speed and the simulated significant wave height(SWH),particularly the peak SWH.The WCI effects between the two wind field simulations were similar;these effects enhanced the SWH throughout the nearshore NECS during both typhoons but suppressed the SWH on the right side of the Typhoon Muifa track in the deep and off shore sea areas.In summary,variations in the water depth and current propagation direction dominate the modulation of wave height.
基金Supported by the Fund of National High Technology Research and Development Program (863 Program, No. 2006AA02Z312)
文摘Study on the quantitative structure-activity relationship （QSAR） of 26 compounds, N-[5-（2-furanyl）-2-methyl-4-oxo-4H-thieno[2,3-d]pyrimidin-3-yl]-carboxamide and 3-substituted- 5-（2-furanyl）-2-methyl-3H-thieno[2,3-d]pyrimidin-4-ones, with three-dimensional holographic vector of atomic interaction field （3D-HoVAIF） was carried out. SMR-PLS QSAR models have been created and good correlation coefficients and cross-validated correlation coefficients were obtained. The result shows that the models have good prediction capability and favorable stability and the 3D-HoVAIF is applicable to the molecular structural characterization and biological activity prediction.
基金the financial support by the National Natural Science Foundation of China as general projects(Grant Nos.51779068,52070066,52211530084,42277059,and 22006029)Tianjin Commission of Science and Technology as key technologies R&D projects(No.21YFSNSN00250)+1 种基金Doctoral Inno-vation Project of Hebei Province(CXZZBS2023031)the Royal Society/International Exchanges 2021 Cost Share/NSFC(Grant No.IEC\NSFC\211142).
文摘Heterojunction photocatalysts have shown considerable activities for organic pollutants degradation.However,the faint connection interface and inferior charge shift efficiency critically block the property of heterojunction photocatalysis.Herein,Bi_(2)O_(2)S/NiFe_(2)O_(4) nanosheets heterojunction with ultrastrong inter-face interaction and high internal electric field are designed by an in-situ growth method.Tentative and theoretical consequences prove that the interfacial interaction and internal electric field not only act as the electron flow bridge but also decrease the electrons shift energy obstacle,thus speeding up electrons transfer and achieving effective spatial electron-hole separation.Therefore,a large amount of·O_(2)^(-)and holes as active species were generated.Remarkably,Bi_(2)O_(2) S/NiFe_(2)O_(4) establishes a considerably boosted photocatalytic performance for tetracycline degradation(0.032 min^(-1)),which is about 14.2-fold and 7.8-fold of the pristine BOS and NFO,respectively.This work provides a promising motivation for modulating charge transfer by interface control and internal electric field to boost photocatalytic performance.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1602501)the National Natural Science Foundation of China(Grant No.12011530060)+1 种基金supported solely by the Russian Science Foundation(Grant No.22-12-00043)supported by the Chinese Academy of Sciences(CAS)Presidents International Fellowship Initiative(PIFI)(Grant Nos.2018VMB0016 and 2022VMC0002),respectively。
文摘We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-lying excited states to the 1s-muon state can lead to the production of electron-positron pairs.We show that the Breit interaction determines the transition probabilities for states with nonzero orbital momentum.We show that the pair production arises mainly from the decay of the 2p states.Thus,the Breit interaction governs electron-positron pair production in bound-bound muon transitions.This process offers a unique opportunity to explore quantum electrodynamics in strong fields,as well as a class of nonradiative transitions involving electron-positron pair production.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11004005 and 60971019)the Young Scholars Fund of Beijing University of Chemical Technology,China(Grant No.QN0724)
文摘This paper theoretically investigates the effects of crystal field and exchange interaction field on magnetic properties in dysprosium gallium garnet under extreme conditions （low temperatures and high magnetic fields） based on quantum theory. Here, five sets of crystal field parameters are discussed and compared. It demonstrates that, only considering the crystal field effect, the experiments can not be successfully explained. Thus, referring to the molecular field theory, an effective exchange field associated with the Dy-Dy exchange interaction is further taken into account. Under special consideration of crystal field and the exchange interaction field, it obtains an excellent agreement between the theoretical results and experiments, and further confirms that the exchange interaction field between rare-earth ions has great importance to magnetic properties in paramagnetic rare-earth gallium garnets.
基金the National Natural Science Foundation Outstanding Youth Foundation (Grant No.52122603)the National Science and Technology Major Project (J2019-Ⅲ-0003–0046)。
文摘Clarifying the gas ingestion mechanism in the turbine disc cavity of marine gas turbines is crucial for ensuring the normal operation of turbines.However, the ingestion is influenced by factors such as the rotational pumping effect, mainstream pressure asymmetry, rotor–stator interaction,and unsteady flow structures, complicating the flow. To investigate the impact of rotor–stator interaction on ingestion, this paper decouples the model to include only the mainstream. This research employs experiments and numerical simulations to examine the effects of varying the flow coefficient through changes in rotational speed and mainstream flow rate. The main objective is to understand the influence of different rotor–stator interactions on the mainstream pressure field, accompanied by mechanistic explanations. The findings reveal inconsistent effects of the two methods for changing the flow coefficient on the mainstream pressure field. Particularly, the pressure distribution on the vane side primarily depends on the mainstream flow rate, while the pressure on the blade side is influenced by the mainstream flow rate and the attack angle represented by the flow coefficient. A larger angle of attack angle can increase pressure on the blade side, even surpassing the pressure on the vane side. Assessing the degree of mainstream pressure unevenness solely based on the pressure difference on the vane side is insufficient. This research provides a basis for subsequent studies on the influence of coupled real turbine rotor–stator interaction on gas ingestion.
文摘A proposal is presented for teleporting Schr*iding-cat states. The process of the teleportation is achieved through the dispersive atom-cavity-field interaction. In this proposal, only measurement on the cavity field and on the singlet atomic states are used.
文摘The resonance interaction of two-state atoms with single mode field is described theoretically by using the semi-classical theory and Jaynes-Cummings model. The nonlinear characteristics of this system are calculated by using FFT and Runge-Kutta methods. The chaotic strange attractors in this system are obtained from the numerical results.
文摘A series of magnetic properties of Tm_2Fe_(14)B are explained quantitatively by the calculations based on the single ion model. The magnetic properties include the temperature dependence of the spontaneous magnetization, the spin reorientation temperature and the magnetization curves along the principal crystal axes at 4.2, 100, 150 and 200 K. The values of the exchange field and the crystalline electric field parameters used in the calculations are μ_BH_(ex)(T=0 K)=135, B_2~0=1.77, B_2~2=±2.97, B_4~0=-3.06×10^(-3), B_4^(-2)=0, B_4~4=-6.82×10^(-3), B_6~0=1.05× 10^(-5), B_6^(-2)=±7.40×10^(-5), B_6~4=1.96×10^(-4), and B_6^(-6)=0 all in K unit. The magnetization processes of the Fe-and Tm-sublattices at different temperatures are analysed. The processes are characterized by the non-collinearity between the magnetic moments of the Fe-and Tm-sublattices.
文摘The interaction problem among fractures under the action of compressional stress is studied in this paper by using the finite element method and boundary element method respectively.The mechanical criteria which differentiate between the independent fractures and fracture systems and their computation methods are presented in this paper.The proportional conditions between length and spacing of fractures that exist interaction for several kinds of fracture groups of different geometric arrangement are given.The effect of interaction among fractures on the displacement field,stress field and strain energy distribution are computed.The relations between the fracture system of conjugate array and conjugate earthquakes are also discussed in this paper.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11205090 and 11175087)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No. 12KJB140008)
文摘The effects of the Dzyaloshinski-Moriya （DM） interaction on the ground-state properties of the anisotropic XY chain in a transverse field have been studied by means of correlation functions and entanglement. Different from the case without the DM interaction, the excitation spectra ek of this model are not symmetrical in the momentum space and are not always positive. As a result, besides the ferromagnetic （FM） and the paramagnetic （PM） phases, a gapless chiral phase is induced. In the chiral phase, the von Neumann entropy is proportional to log2 L （L is the length of a subchain） with the coefficient A ~ 1/3, which is the same as that of the XY chain in a transverse field without the DM interaction for 7 = 0 and 0 〈 h 〈 1. And in the vicinity of the critical point between the chiral phase and the FM （or PM） phase, the behaviors of the nearest- neighbor concurrence and its derivative are like those for the anisotropy transition.
基金supported by the National Natural Science Foundation of China(Grant No.12104407)the Natural Science Foundation of Zhejiang Province(Grant No.LQ20A040004)。
文摘There have been intensive studies on Kitaev materials for the sake of realization of exotic states such as quantum spin liquid and topological orders.In realistic materials,the Kitaev interaction may coexist with the Dzyaloshinskii–Moriya interaction,and it is of challenge to distinguish their magnitudes separately.Here,we study the topological magnon excitations and related thermal Hall conductivity of kagome magnet exhibiting Heisenberg,Kitaev and Dzyaloshinskii–Moriya interactions exposed to a magnetic field.In a strong magnetic field perpendicular to the plane of the lattice([111]direction)that brings the system into a fully polarized paramagnetic phase,we find that the magnon bands carry nontrivial Chern numbers in the full region of the phase diagram.Furthermore,there are phase transitions related to two topological phases with opposite Chern numbers,which lead to the sign changes of the thermal Hall conductivity.In the phase with negative thermal conductivity,the Kitaev interaction is relatively large and the width of the phase increases with the strength of Dzyaloshinskii–Moriya interaction.Hence,the present study will contribute to the understanding of related compounds.
基金The project supported by National Natural Science Foundation of China under Grant No. 60671042 and the Fundamental Research Foundation for Key Projects of Shanghai Science and Technology Committee under Grant No. 06JC14032 tCorresponding author,
文摘We study electronic transport through a quantum dot （QD） with a precessing magnetic field. By using the Keldysh nonequilibrium Green function method, formulas of local density of states （LDOS） and conductance of QD are derived self-consistently. It shows that the LDOS and conductance have obvious changes with the Coulomb blockade interaction. The intensity and angle of the magnetic field or temperatures, which reflect the mesoscopic structure of the QD are derived. The superiority of this device is that the QD can be controlled easily by the magnetic field, so it is valuable to apply in generating, manipulating and probing spin state.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11204061,11374085,11104057,11274010 and 11204002the Anhui Provincial Natural Science Foundation under Grant No 1408085MA16+4 种基金the Anhui Provincial Candidates for Academic and Technical Leaders Foundation under Grant No 2015H052the Discipline Top-Notch Talents Foundationthe Excellent Young Talents Support Plan of Anhui Provincial Universitiesthe Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20113401110002the 211 Project of Anhui University,and the Personnel Department of Anhui Province
文摘We investigate the effects of pure Dzyaloshinskii Moriya （DM） interaction with magnetic field on entanglement in intrinsic decoherence, assuming that the system is initially in four Bell states ｜φ±〉 = （｜00） ± ｜11〉）/√2 and ｜ψ±〉 = （｜01） ±｜10〉）/√2, respectively. It is found that if the system is initially in the state p1（0） = ｜φ＋〉〈φ＋1, the entanglement can obtain its maximum when the DM interaction vector D is in the plane of XOZ and magnetic field B = By with the infinite time t, moreover the entanglement is independent of By and t when By is perpendicular to D. In addition, we obtain similar results when the system is initially in the states p2（0） = ｜φ-〉〈φ-｜ or p3 （0） = ｜ψ＋〉〈ψ＋1. However, we find that if the system is initially in the state P4 （0） = ｜ψ-〉〈ψ-l, the entanglement can obtain its maximum for infinite t, when the DM vector is in the plane ofYOZ, XOZ, or XOY, with the magnetic field parallel to X, Y, or Z axis, respectively. Moreover, when the axial B is perpendicular to D for the initial state p4（O）, the negativity oscillates with time t and reaches a stable value, the larger the value of B is, the greater the stable value is, and the shorter the oscillation time of the negativity is. Thus we can adjust the direction and value of the external magnetic field to obtain the maximal entanglement, and avoid the adverse effects of external environment in some initial state. This is feasible within the cun＇ent experimental technology.
