SmCo/FeCo/SmCo trilayer was deposited with two different thickness configurations for soft phase (FeCo);50 nm/10 nm/50 nm and 50 nm/25 nm/50 nm were deposited on Si (111) substrate and Ta (50 nm) seed layer by RF magn...SmCo/FeCo/SmCo trilayer was deposited with two different thickness configurations for soft phase (FeCo);50 nm/10 nm/50 nm and 50 nm/25 nm/50 nm were deposited on Si (111) substrate and Ta (50 nm) seed layer by RF magnetron sputtering in a pressure, p, of 30 - 35 m Torr. After deposition the films were annealed under Ar atmosphere at temperature T equal to 923 and 973 for different times followed by quenching in water. X-ray diffraction patterns were obtained to identified phase presents and calculate average crystallite size. To study the effect of configuration thickness in soft phases, DC magnetic measurements were carried out;the measurements were done in the temperature interval of 300 - 50 K. Hysteresis loops collected at low temperatures exposed an increment in coercivity with the decrease of T and at same time, presented a “knee” in the second quadrant of the demagnetization curve, which suggests that the inter-layer exchange coupling becomes less effective, being more evident for sample with 50 nm/25 nm/50 nm thickness. Moreover, δM (H) plots were calculated from magnetic measurements at three different temperatures, T, equal to 300, 150 and 50 K, which corroborates that the dipolar interactions became stronger when thickness of soft phases increases. Finally, the thickness effect is attributed to the SmCo5 phase magnetocrystalline anisotropy constant, which is responsible for the exchange coupling length.展开更多
The influence of annealing time on the magnetic properties and microstructure of nanocomposite Pr7.5Dy1Fe71Co15Nb1B4.5 ribbons was systematically investigated by the methods of vibrating sample magnetometer （VSM）, ...The influence of annealing time on the magnetic properties and microstructure of nanocomposite Pr7.5Dy1Fe71Co15Nb1B4.5 ribbons was systematically investigated by the methods of vibrating sample magnetometer （VSM）, X-ray diffraction （XRD） and high resolution transmission electron microscopy （HRTEM）. Interaction domains derived from strong exchange coupling interactions between hard and soft magnetic grains were imaged using magnetic force microscopy （MFM）. Maximum remanence, intrinsic coercivity, and maximum energy product values were obtained in the ribbons annealed at 700℃ for 15 min, which were composed of Pr2（Fe, Co）14B, α-（Fe, Co）, and slight Pr2（Fe, CO）17 phases. Although Jr, Hci, and （Bn）max decreased gradually with further increase of annealing time, it is emphasized that comparatively high Jr and Hci and （BH）max were obtained in a wide annealing time period of 15 to 360 min. The shape of initial magnetization curves and hysteresis loops change as a function of annealing time, indicating different magnetization reversal routes, which can be fully explained by the corresponding microstructure.展开更多
In this work,a method is put forward to obtain the dynamic solution efficiently and accurately for a large-scale train-track-substructure(TTS)system.It is called implicit-explicit integration and multi-time-step solut...In this work,a method is put forward to obtain the dynamic solution efficiently and accurately for a large-scale train-track-substructure(TTS)system.It is called implicit-explicit integration and multi-time-step solution method(abbreviated as mI-nE-MTS method).The TTS system is divided into train-track subsystem and substruc-ture subsystem.Considering that the root cause of low effi-ciency of obtaining TTS solution lies in solving the alge-braic equation of the substructures,the high-efficient Zhai method,an explicit integration scheme,can be introduced to avoid matrix inversion process.The train-track system is solved by implicitly Park method.Moreover,it is known that the requirement of time step size differs for different sub-systems,integration methods and structural frequency response characteristics.A multi-time-step solution is pro-posed,in which time step size for the train-track subsystem and the substructure subsystem can be arbitrarily chosen once satisfying stability and precision demand,namely the time spent for m implicit integral steps is equal to n explicit integral steps,i.e.,mI=nE as mentioned above.The numeri-cal examples show the accuracy,efficiency,and engineering practicality of the proposed method.展开更多
The exchange interaction between the electrons in the different magnetic ions and the spin-fluctuation of the magnetic ions exist in the paramagnetic media NdF3. The exchange interaction between the electrons in the d...The exchange interaction between the electrons in the different magnetic ions and the spin-fluctuation of the magnetic ions exist in the paramagnetic media NdF3. The exchange interaction between the electrons in the different magnetic ions may be equivalent to an effective field Hin that is in direct proportion to the magnetization M. The spin-fluctuation of the magnetic ions leads the coefficient of the effective field to vary with temperature. The effective field is given as Hin = -（0.75 ＋ 0.22T） × 10^-5M in NdF3. When the secondary crystal field effect is taken into account, the magnetic susceptibility and Verdet constant are calculated for NdF3 by means of the effective field Hin and the applied field He. The calculated results are in agreement with the measured ones.展开更多
The ＂integration of informatization and industrialization＂ is a constant development process. In China, the integration of industrial economy and information economy is an inevitable trend of economy development. Th...The ＂integration of informatization and industrialization＂ is a constant development process. In China, the integration of industrial economy and information economy is an inevitable trend of economy development. The social formation of the current industrial society in China will inevitably transform into the social formation of the integration of industrial society and information society. The ＂integration of informatization and industrialization＂ provides necessary technology for economic development,which makes the society have an overall change. This paper tries to make a comparison of the basic features of different formations from the historical development process of the era, in order to summarize the basic characteristics of ＂integration of informatization and industralization＂ and its interaction relationship with industrial design.展开更多
The groundwater(GW)in the floodplain riparian area frequently interacts intensely with surface water(SW).Heat as a tracer is one of the hot research fields in investigating GW-SW interactions,and analytical approaches...The groundwater(GW)in the floodplain riparian area frequently interacts intensely with surface water(SW).Heat as a tracer is one of the hot research fields in investigating GW-SW interactions,and analytical approaches have been proposed for the calculation of exchange flow velocity.However,few studies have considered the effects of very dynamic flow conditions and monitoring instrumentation on the calculation with field measured data.Herein,taking the middle reaches of the Heihe River as the study area,different types of monitoring wells were constructed under the riverbed and near the river,and multiple methods(Darcy’s law,heat tracing,and isotopic mixing methods)were employed to trace the exchanges between the river and groundwater.The results indicate that different methods demonstrate diverse information with obvious unevenly distributed flux along the vertical direction.And the combination of multiple methods has an important role in studying the interaction between GW and SW.Fully screened wells produce intraborehole flow and disturb the heat transport,which is relevant to flow velocity,and further affects the temperature distribution,impacting the temperature-based flow velocity calculation.Dynamic flow conditions aggravate riverbed sediment disturbances,e.g.,scour and deposition,and additionally affect the interaction and monitoring data.展开更多
Schizophrenia is characterized by psychotic symptoms,negative symptoms,and cognitive deficits,profoundly affecting individuals and their families.The etiology is multifactorial,involving genetic,endocrine,and immunolo...Schizophrenia is characterized by psychotic symptoms,negative symptoms,and cognitive deficits,profoundly affecting individuals and their families.The etiology is multifactorial,involving genetic,endocrine,and immunological risk factors.It is thought that schizophrenia is exclusively linked to alterations in brain structure and function,while the relationship between the brain and many organs may lack sufficient attention.Increasing evidence indicates abnormalities of the interactions between the brain and many organs in patients with schizophrenia.Inter-organ crosstalk affects the onset,course,and management of schizophrenia.Besides,the complex relationship between autonomic nervous system,endocrine system,and immune system further facilitates the development of schizophrenia.The present review summarizes the relationships between the brain and multiple organ systems in schizophrenia,providing new perspectives on the underlying pathophysiological mechanisms of schizophrenia.展开更多
Exchange interaction plays an important role on magnetic properties of nanocomposite magnets consisting of hard- and soft-magnetic phases. Here the exchange interaction in the Sm-Co/Co （and Fe65Co35） magnetic films ...Exchange interaction plays an important role on magnetic properties of nanocomposite magnets consisting of hard- and soft-magnetic phases. Here the exchange interaction in the Sm-Co/Co （and Fe65Co35） magnetic films was characterized by measuring static （mr（H）） and demagnetized （md（H）） remanence curves. According to conventional method： δm（H）=md（H） - [1 - 2mr（H）], the exchange interaction was evaluated. The switching fields H′p and Hp, at which static （mr（H）） and demagnetized （md（H）） remanence show the fastest change, were identified. The relative ratio η=Hp-H′p/Hp of switching fields H′p and Hp has a linear relationship with the maximum value δmmax of δm（H） curves, proposing an alternative way to characterize the exchange interaction.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
In present investigation exchange interactions of Pr_(n+1)Co_(3n+5)B_(2n)-type compounds have been evalu- ated in the light of molecular-field theory. The exchange interactions and ferromagnetism in these compounds ar...In present investigation exchange interactions of Pr_(n+1)Co_(3n+5)B_(2n)-type compounds have been evalu- ated in the light of molecular-field theory. The exchange interactions and ferromagnetism in these compounds are discussed in terms of lattice parameters and interatomic distance between Co atom.展开更多
The dynamic properties of interacting vortex-antivortex pairs in thin film are studied by analytical calculations. An- alytical expressions for the magnetization vector distribution of vortex-antivortex pairs and the ...The dynamic properties of interacting vortex-antivortex pairs in thin film are studied by analytical calculations. An- alytical expressions for the magnetization vector distribution of vortex-antivortex pairs and the trivortex states are given. The magnetic states of the vortices are treated as having rigid structures, i.e., the vortex maintains its spin distribution when moving. The trajectories of the vortex cores are calculated by the Thiele＇s equation. It is found that the vortex-antivortex pair rotates around each other when they have opposite polarities, however, vortex and antivortex cores move along straight lines when they have the same polarity. The frequency of the rotation decreases with increasing the distance between the two cores of vortex-antivortex pair, and it has a lower value when a third vortex is introduced.展开更多
Based on a single ion model, Hamiltonian of the simplest form about magnetocrystalline anisotropy for Tb3+ ion was solved by using the numerical method. The relation between the stabilization energy, crystal field coe...Based on a single ion model, Hamiltonian of the simplest form about magnetocrystalline anisotropy for Tb3+ ion was solved by using the numerical method. The relation between the stabilization energy, crystal field coefficient B20 and the magnetic exchange interaction was studied as temperature approaches to 0 K. The results show that the stabilization energy contributed by Tb3+ is linear with crystal field coefficient B20 approximately, but it is insensitive to the change of magnetic exchange interaction for the strong magnetic substances such as TbCo5, Tb2Co17 and Tb2Fe14B compounds.展开更多
Integrated energy systems(IES)are widely regarded as a key enabler of carbon neutrality,enabling the coordinated use of electricity,heat,and gas to support large-scale renewable integration.Yet their practical deploym...Integrated energy systems(IES)are widely regarded as a key enabler of carbon neutrality,enabling the coordinated use of electricity,heat,and gas to support large-scale renewable integration.Yet their practical deployment still faces major challenges,including rigid thermoelectric coupling,insufficient operational flexibility,and fragmented carbon and certificate market mechanisms.To address these issues,this study proposes a low-carbon economic dispatch model for integrated energy systems(IES)that reduces emissions and costs while improving renewable energy utilization.A coordinated framework integrating carbon capture,utilization,and storage,two-stage power-to-gas,combined heat and power,and ground-source heat pump technologies enhances multi-energy complementarity and overcomes the heat-led constraints of traditional combined heat and power systems.A unified carbon emission trading and green certificate trading mechanism is designed to balance economic and environmental goals through cross-market synergy.To address uncertainty,a distributionally robust chance-constrained model based on Kullback-Leibler divergence is introduced in Scenario 8.The model is solved using the GUROBI solver under multiple scenarios.Simulation results show a cost reduction from$56,166.66 to$25,840.32,carbon emission cuts from 801.38to 440.90 t,and wind/photovoltaic utilization rates reaching 98%,which fully demonstrates the effectiveness of the proposed framework in achieving cost-efficient low-carbon operation of IES.展开更多
Structure, magnetic properties and magnetostriction of Sm0.9Pr0.1(Fe1-xCox)2 compounds have been investigated by means of X-ray diffraction, a.c. initial susceptibility, extracting sample magnetometer, Mossbauer spec-...Structure, magnetic properties and magnetostriction of Sm0.9Pr0.1(Fe1-xCox)2 compounds have been investigated by means of X-ray diffraction, a.c. initial susceptibility, extracting sample magnetometer, Mossbauer spec-troscopy and standard strain gauge techniques. The lattice parameter a of the MgCu2-type Laves compounds Sm0.9Pr0.1(Fe1-xCox)2 decreases nonlinearly with increasing Co concentration, deviating from the Vegard's law. Curie temperature Tc increases initially from 668 K for x=0 to 694 K for x=0.2 and then decreases to 200 K for x=1.0. The saturation magnetization Ms at temperatures 1.5 K, 77 K and 300 K have the same variation tendency as the composition dependence of Curie temperature, in consistence with rigid-band model. The easy magnetization direction (EMD) of Sm0.9Pr0.1(Fe1-xCox)2 lies along [111] direction in the range x<0.6, and changes to [110] for x=0.8, while Sm0.9Pr0.1Co2 stays in the paramagnetic state at room temperature. The composition dependence of the average hyperfine field,Hhf , demonstrates a similar variation tendency as that of the saturation magnetization Ms and Curie temperature Tc. The spontaneous magnetostricton Am increases with increasing Co content. The saturation magnetostriction λs decreases monotonically with increasing x, which is caused by the increase of magnetostriction constant λ100 with opposite sign to that of Am. A two-sublattice model has been proposed to understand the intermediate region between the [111] and [110] spin configurations, which can also be used to explain the temperature dependence of magnetization.展开更多
Electron spins confined in semiconductor quantum dots(QDs)are one of potential candidates for physical implementation of scalable quantum information processing technologies.Tunnel coupling based inter exchange intera...Electron spins confined in semiconductor quantum dots(QDs)are one of potential candidates for physical implementation of scalable quantum information processing technologies.Tunnel coupling based inter exchange interaction between QDs is crucial in achieving single-qubit manipulation,two-qubit gate,quantum communication and quantum simulation.This review first provides a theoretical perspective that surveys a general framework,including the Helter−London approach,the Hund−Mulliken approach,and the Hubbard model,to describe the inter exchange interactions between semiconductor quantum dots.An electrical method to control the inter exchange interaction in a realistic device is proposed as well.Then the significant achievements of inter exchange interaction in manipulating single qubits,achieving two-qubit gates,performing quantum communication and quantum simulation are reviewed.The last part is a summary of this review.展开更多
When a ferromagnet(FM)couples to a spin glass(SG),the hidden nature of SG may imprint on the FM via their interfacial coupling,probably resulting in elongated magnetic relaxation and enhanced unidirectional and uniaxi...When a ferromagnet(FM)couples to a spin glass(SG),the hidden nature of SG may imprint on the FM via their interfacial coupling,probably resulting in elongated magnetic relaxation and enhanced unidirectional and uniaxial anisotropies.In parallel with the study of interfacial roles,e.g.interfacial coupling and matching,we focused on the influence of the competing interactions in SG(JSG)on the magnetic relaxation properties of SG/FM bilayer and the FM magnetization reversal involving exchange bias field(HE)and coercivity(HC).A fastest decay of relaxation in SG/FM bilayer is found at an intermediate JSG^5.2 erg/cm2 and the relaxation parameters related to JSG are nonmonotonic.On the other hand,a pronounced HE of^0.26 kOe is observed at small JSG,and as JSG increases larger than 2.275 erg/cm2,HE decreases by an order of magnitude and levels off,i.e.,a net EB remains.He is sensitive to JSG only at JSG above 2.275 erg/cm2 and exhibits a minimum value at JSG=4.55 erg/cm2,just below 5.2 erg/cm2 where the relaxation decay is the fastest.Microscopic analysis unravels that the net magnetization associated with unidirectional magnetic stabilization and the large-area FM-like domains in SG are favored at small JSG,while with increasing JSG,the SG spins spontaneously reverse and thus the energy barriers are smeared out.A high susceptibility and a strong interfacial coupling lead to FM magnetization reversal under weaker fields and thus a decrease in coercivity.For too large JSG(exceeding 5.2 erg/cm2),magnetic frustration extends over the domains in SG meanwhile fierce energy competition occurs frequently,resembling enhanced quantum fluctuations.As a result,dynamic relaxation and statistic coercivity are both recovered.This work tells us that the independent modulations of unidirectional and uniaxial anisotropies are possible in SG-based systems through precisely controlling JSG,which is desired for application in the read/write head in future data storage media.展开更多
Background:Musical perception requires a host of skills.Instrumental musicians place greater emphasis on motor coordination,whereas vocal musicians rehearse vocal sounds.The study explored the differential advantages ...Background:Musical perception requires a host of skills.Instrumental musicians place greater emphasis on motor coordination,whereas vocal musicians rehearse vocal sounds.The study explored the differential advantages of musical background on binaural integration and interaction in musicians(instrumentalists,vocalists)and compared them with age-matched non-musicians.Methods:Eight six participants aged 20e40 y with normal hearing sensitivity were subjected to binaural tests using a standard group comparison research design.The participants were segregated into three groups e Group 1 included instrumentalists(n?26,mean age:17.73±2.83 y),while Group 2 and Group 3 consisted of vocalists(n?30,mean age:19.30±2.47 y)and non-musicians(n?30,mean age:18.20±3.02 y)respectively.The binaural processes namely integration(Dichotic syllable test,DST;and virtual acoustic space identification-VASI)and interaction(Interaural difference thresholds for time and level:ITD&ILD),were administered on all the participants.Results:Statistical analyses showed the main effect of musicianship.Bonferroni pair-wise test revealed that the musicians(instrumentalists and vocalists)outperformed(p<0.05)non-musicians in all the tests.The differential advantage of the musical background was seen on the binaural integration test with instrumentalists performing better in the VASI test compared to vocalists,and vice-versa for DST.No difference was observed in interaction tasks(ITD&ILD)between vocalists and instrumentalists(p>0.05).Conclusion:Musical background-induced differential advantages can be reasonably noted in the binaural skills of instrumentalists and vocalists(compared to non-musicians).展开更多
Taking α-Fe and Nd_2Fe_(14)B grains as example, the grain size dependence of the exchange-coupling interaction and effective anisotropy and also their variations depending on the ratio of magnetically soft and hard g...Taking α-Fe and Nd_2Fe_(14)B grains as example, the grain size dependence of the exchange-coupling interaction and effective anisotropy and also their variations depending on the ratio of magnetically soft and hard grain sizes, D_s∶D_h, were investigated. When grain size D>L_(ex), the grain’s anisotropy is the statistic value of the coupled and uncoupled part. The anisotropy constant of uncoupled part is the common value K_1 and that of coupled part varies with the distance to the grain surface. The effective anisotropy constant between magnetically soft and hard grains, K_(eff), can be expressed as the sum of the products of volume fractions for soft and hard grains, respectively, and the corresponding mean anisotropy constants. The calculation results indicate that the exchange-coupling interaction is enhanced with the reduction of grain size, and the effective anisotropy decreases with reducing grain size and increasing ratio of D_s∶D_h. In order to get high effective anisotropy constant, K_(eff), in composite magnetically soft-hard grains, the hard grain size should be larger than 30 nm and the soft grain size should be about 10 nm.展开更多
The temperature dependence of lattice parameters a and c of intermetallic compounds RMn 2Ge 2(R=La, Sm and Gd)were measured in the temperature range of 10800 K by using the X-ray diffractometer . It is found that the ...The temperature dependence of lattice parameters a and c of intermetallic compounds RMn 2Ge 2(R=La, Sm and Gd)were measured in the temperature range of 10800 K by using the X-ray diffractometer . It is found that the high temperature magnetic transitions of Mn-subsystem in light rare earth compounds from paramagnetic to antiferromagnetic state accompany the negative magnetoelastic anomalies of lattice parameters c, where a does not change. This indicates that the antiferromagnetic component of intralayer Mn-Mn exchange coupling is correlated with lattice constant c. The low temperature first order ferromagnetism→antiferromagnetism transitions(or antiferromagnetism→ferromagnetism transition) of Mn-subsystem in SmMn 2Ge 2 and GdMn 2Ge 2 accompany the abruptly decrease(or increase) of lattice parameter a, and Δa/a≈0.15%. This demonstrates that the interlayer Mn-Mn exchange interaction is very sensitive to the intralayer Mn-Mn distance. The critical value of lattice constant a k, at which the interlayer Mn-Mn coupling changes its sign, is 4.044 5×10 -10 m. Based on the molecular field model of exchange interaction the magnetic curves of GdMn 2Ge 2 single crystal at different temperatures were calculated and a good agreement with experimental data had gotten. The Gd-Gd, Gd-Mn, intralayer Mn-Mn and interlayer Mn-Mn exchange coupling parameters were estimated.展开更多
The commonly used discretization approaches for distributed hydrological models can be broadly categorized into four types,based on the nature of the discrete components:Regular Mesh,Triangular Irregular Networks(TINs...The commonly used discretization approaches for distributed hydrological models can be broadly categorized into four types,based on the nature of the discrete components:Regular Mesh,Triangular Irregular Networks(TINs),Representative Elementary Watershed(REWs) and Hydrologic Response Units(HRUs).In this paper,a new discretization approach for landforms that have similar hydrologic properties is developed and discussed here for the Integrated Hydrologic Model(IHM),a combining simulation of surface and groundwater processes,accounting for the interaction between the systems.The approach used in the IHM is to disaggregate basin parameters into discrete landforms that have similar hydrologic properties.These landforms may be impervious areas,related areas,areas with high or low clay or organic fractions,areas with significantly different depths-to-water-table,and areas with different types of land cover or different land uses.Incorporating discrete landforms within basins allows significant distributed parameter analysis,but requires an efficient computational structure.The IHM integration represents a new approach interpreting fluxes across the model interface and storages near the interface for transfer to the appropriate model component,accounting for the disparate discretization while rigidly maintaining mass conservation.The discretization approaches employed in IHM will provide some ideas and insights which are helpful to those researchers who have been working on the integrated models for surface-groundwater interaction.展开更多
文摘SmCo/FeCo/SmCo trilayer was deposited with two different thickness configurations for soft phase (FeCo);50 nm/10 nm/50 nm and 50 nm/25 nm/50 nm were deposited on Si (111) substrate and Ta (50 nm) seed layer by RF magnetron sputtering in a pressure, p, of 30 - 35 m Torr. After deposition the films were annealed under Ar atmosphere at temperature T equal to 923 and 973 for different times followed by quenching in water. X-ray diffraction patterns were obtained to identified phase presents and calculate average crystallite size. To study the effect of configuration thickness in soft phases, DC magnetic measurements were carried out;the measurements were done in the temperature interval of 300 - 50 K. Hysteresis loops collected at low temperatures exposed an increment in coercivity with the decrease of T and at same time, presented a “knee” in the second quadrant of the demagnetization curve, which suggests that the inter-layer exchange coupling becomes less effective, being more evident for sample with 50 nm/25 nm/50 nm thickness. Moreover, δM (H) plots were calculated from magnetic measurements at three different temperatures, T, equal to 300, 150 and 50 K, which corroborates that the dipolar interactions became stronger when thickness of soft phases increases. Finally, the thickness effect is attributed to the SmCo5 phase magnetocrystalline anisotropy constant, which is responsible for the exchange coupling length.
基金This work was financially supported by the National Natural Science Foundation of China (No.10074005)
文摘The influence of annealing time on the magnetic properties and microstructure of nanocomposite Pr7.5Dy1Fe71Co15Nb1B4.5 ribbons was systematically investigated by the methods of vibrating sample magnetometer （VSM）, X-ray diffraction （XRD） and high resolution transmission electron microscopy （HRTEM）. Interaction domains derived from strong exchange coupling interactions between hard and soft magnetic grains were imaged using magnetic force microscopy （MFM）. Maximum remanence, intrinsic coercivity, and maximum energy product values were obtained in the ribbons annealed at 700℃ for 15 min, which were composed of Pr2（Fe, Co）14B, α-（Fe, Co）, and slight Pr2（Fe, CO）17 phases. Although Jr, Hci, and （Bn）max decreased gradually with further increase of annealing time, it is emphasized that comparatively high Jr and Hci and （BH）max were obtained in a wide annealing time period of 15 to 360 min. The shape of initial magnetization curves and hysteresis loops change as a function of annealing time, indicating different magnetization reversal routes, which can be fully explained by the corresponding microstructure.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.52008404,U1934217 and 11790283)Science and Technology Research and Development Program Project of China Railway Group Limited(Major Special Project,No.2020-Special-02)the National Natural Science Foundation of Hunan Province(Grant No.2021JJ30850).
文摘In this work,a method is put forward to obtain the dynamic solution efficiently and accurately for a large-scale train-track-substructure(TTS)system.It is called implicit-explicit integration and multi-time-step solution method(abbreviated as mI-nE-MTS method).The TTS system is divided into train-track subsystem and substruc-ture subsystem.Considering that the root cause of low effi-ciency of obtaining TTS solution lies in solving the alge-braic equation of the substructures,the high-efficient Zhai method,an explicit integration scheme,can be introduced to avoid matrix inversion process.The train-track system is solved by implicitly Park method.Moreover,it is known that the requirement of time step size differs for different sub-systems,integration methods and structural frequency response characteristics.A multi-time-step solution is pro-posed,in which time step size for the train-track subsystem and the substructure subsystem can be arbitrarily chosen once satisfying stability and precision demand,namely the time spent for m implicit integral steps is equal to n explicit integral steps,i.e.,mI=nE as mentioned above.The numeri-cal examples show the accuracy,efficiency,and engineering practicality of the proposed method.
基金Project supported by the Science and Technology Foundation of China University of Mining and Technology (Grant No OK061066)
文摘The exchange interaction between the electrons in the different magnetic ions and the spin-fluctuation of the magnetic ions exist in the paramagnetic media NdF3. The exchange interaction between the electrons in the different magnetic ions may be equivalent to an effective field Hin that is in direct proportion to the magnetization M. The spin-fluctuation of the magnetic ions leads the coefficient of the effective field to vary with temperature. The effective field is given as Hin = -（0.75 ＋ 0.22T） × 10^-5M in NdF3. When the secondary crystal field effect is taken into account, the magnetic susceptibility and Verdet constant are calculated for NdF3 by means of the effective field Hin and the applied field He. The calculated results are in agreement with the measured ones.
文摘The ＂integration of informatization and industrialization＂ is a constant development process. In China, the integration of industrial economy and information economy is an inevitable trend of economy development. The social formation of the current industrial society in China will inevitably transform into the social formation of the integration of industrial society and information society. The ＂integration of informatization and industrialization＂ provides necessary technology for economic development,which makes the society have an overall change. This paper tries to make a comparison of the basic features of different formations from the historical development process of the era, in order to summarize the basic characteristics of ＂integration of informatization and industralization＂ and its interaction relationship with industrial design.
基金supported by the National Natural Science Foundations of China(No.42425207)the Key R&D Program of the Xinjiang Uygur Autonomous Region(No.2024B03022).
文摘The groundwater(GW)in the floodplain riparian area frequently interacts intensely with surface water(SW).Heat as a tracer is one of the hot research fields in investigating GW-SW interactions,and analytical approaches have been proposed for the calculation of exchange flow velocity.However,few studies have considered the effects of very dynamic flow conditions and monitoring instrumentation on the calculation with field measured data.Herein,taking the middle reaches of the Heihe River as the study area,different types of monitoring wells were constructed under the riverbed and near the river,and multiple methods(Darcy’s law,heat tracing,and isotopic mixing methods)were employed to trace the exchanges between the river and groundwater.The results indicate that different methods demonstrate diverse information with obvious unevenly distributed flux along the vertical direction.And the combination of multiple methods has an important role in studying the interaction between GW and SW.Fully screened wells produce intraborehole flow and disturb the heat transport,which is relevant to flow velocity,and further affects the temperature distribution,impacting the temperature-based flow velocity calculation.Dynamic flow conditions aggravate riverbed sediment disturbances,e.g.,scour and deposition,and additionally affect the interaction and monitoring data.
基金Supported by Beijing Traditional Chinese Medicine Scientific and Technological Development Fund Project,No.BJZYYB-2023-66Beijing Natural Science Foundation,No.7212050the Capital’s Funds for Health Improvement and Research,No.2020-4-2126.
文摘Schizophrenia is characterized by psychotic symptoms,negative symptoms,and cognitive deficits,profoundly affecting individuals and their families.The etiology is multifactorial,involving genetic,endocrine,and immunological risk factors.It is thought that schizophrenia is exclusively linked to alterations in brain structure and function,while the relationship between the brain and many organs may lack sufficient attention.Increasing evidence indicates abnormalities of the interactions between the brain and many organs in patients with schizophrenia.Inter-organ crosstalk affects the onset,course,and management of schizophrenia.Besides,the complex relationship between autonomic nervous system,endocrine system,and immune system further facilitates the development of schizophrenia.The present review summarizes the relationships between the brain and multiple organ systems in schizophrenia,providing new perspectives on the underlying pathophysiological mechanisms of schizophrenia.
基金financially supported by the National High-Tech Research and Development Program of China("863"Program)under Grant No.2002AA302603the National Natural Science Foundation of China under Grant Nos.50071062,59725103,and 50331030.
文摘Exchange interaction plays an important role on magnetic properties of nanocomposite magnets consisting of hard- and soft-magnetic phases. Here the exchange interaction in the Sm-Co/Co （and Fe65Co35） magnetic films was characterized by measuring static （mr（H）） and demagnetized （md（H）） remanence curves. According to conventional method： δm（H）=md（H） - [1 - 2mr（H）], the exchange interaction was evaluated. The switching fields H′p and Hp, at which static （mr（H）） and demagnetized （md（H）） remanence show the fastest change, were identified. The relative ratio η=Hp-H′p/Hp of switching fields H′p and Hp has a linear relationship with the maximum value δmmax of δm（H） curves, proposing an alternative way to characterize the exchange interaction.
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.
文摘In present investigation exchange interactions of Pr_(n+1)Co_(3n+5)B_(2n)-type compounds have been evalu- ated in the light of molecular-field theory. The exchange interactions and ferromagnetism in these compounds are discussed in terms of lattice parameters and interatomic distance between Co atom.
基金Project supported by the National Natural Science Foundation of China(Grant No.11204026)the Fundamental Research Funds for Central Universities of the Ministry of Education of China(Grant No.n130405011)
文摘The dynamic properties of interacting vortex-antivortex pairs in thin film are studied by analytical calculations. An- alytical expressions for the magnetization vector distribution of vortex-antivortex pairs and the trivortex states are given. The magnetic states of the vortices are treated as having rigid structures, i.e., the vortex maintains its spin distribution when moving. The trajectories of the vortex cores are calculated by the Thiele＇s equation. It is found that the vortex-antivortex pair rotates around each other when they have opposite polarities, however, vortex and antivortex cores move along straight lines when they have the same polarity. The frequency of the rotation decreases with increasing the distance between the two cores of vortex-antivortex pair, and it has a lower value when a third vortex is introduced.
文摘Based on a single ion model, Hamiltonian of the simplest form about magnetocrystalline anisotropy for Tb3+ ion was solved by using the numerical method. The relation between the stabilization energy, crystal field coefficient B20 and the magnetic exchange interaction was studied as temperature approaches to 0 K. The results show that the stabilization energy contributed by Tb3+ is linear with crystal field coefficient B20 approximately, but it is insensitive to the change of magnetic exchange interaction for the strong magnetic substances such as TbCo5, Tb2Co17 and Tb2Fe14B compounds.
文摘Integrated energy systems(IES)are widely regarded as a key enabler of carbon neutrality,enabling the coordinated use of electricity,heat,and gas to support large-scale renewable integration.Yet their practical deployment still faces major challenges,including rigid thermoelectric coupling,insufficient operational flexibility,and fragmented carbon and certificate market mechanisms.To address these issues,this study proposes a low-carbon economic dispatch model for integrated energy systems(IES)that reduces emissions and costs while improving renewable energy utilization.A coordinated framework integrating carbon capture,utilization,and storage,two-stage power-to-gas,combined heat and power,and ground-source heat pump technologies enhances multi-energy complementarity and overcomes the heat-led constraints of traditional combined heat and power systems.A unified carbon emission trading and green certificate trading mechanism is designed to balance economic and environmental goals through cross-market synergy.To address uncertainty,a distributionally robust chance-constrained model based on Kullback-Leibler divergence is introduced in Scenario 8.The model is solved using the GUROBI solver under multiple scenarios.Simulation results show a cost reduction from$56,166.66 to$25,840.32,carbon emission cuts from 801.38to 440.90 t,and wind/photovoltaic utilization rates reaching 98%,which fully demonstrates the effectiveness of the proposed framework in achieving cost-efficient low-carbon operation of IES.
基金This work has been supported by the projects No.59725103 and 59871054 of the National Natural Sciences Foundation of China and by the Science and Technology Commnission of Shenyang and Liaoning.Z.J.Guo as aiso indebted to Prof.A.S.Miarkosyan(Russia)for helpful discussions.
文摘Structure, magnetic properties and magnetostriction of Sm0.9Pr0.1(Fe1-xCox)2 compounds have been investigated by means of X-ray diffraction, a.c. initial susceptibility, extracting sample magnetometer, Mossbauer spec-troscopy and standard strain gauge techniques. The lattice parameter a of the MgCu2-type Laves compounds Sm0.9Pr0.1(Fe1-xCox)2 decreases nonlinearly with increasing Co concentration, deviating from the Vegard's law. Curie temperature Tc increases initially from 668 K for x=0 to 694 K for x=0.2 and then decreases to 200 K for x=1.0. The saturation magnetization Ms at temperatures 1.5 K, 77 K and 300 K have the same variation tendency as the composition dependence of Curie temperature, in consistence with rigid-band model. The easy magnetization direction (EMD) of Sm0.9Pr0.1(Fe1-xCox)2 lies along [111] direction in the range x<0.6, and changes to [110] for x=0.8, while Sm0.9Pr0.1Co2 stays in the paramagnetic state at room temperature. The composition dependence of the average hyperfine field,Hhf , demonstrates a similar variation tendency as that of the saturation magnetization Ms and Curie temperature Tc. The spontaneous magnetostricton Am increases with increasing Co content. The saturation magnetostriction λs decreases monotonically with increasing x, which is caused by the increase of magnetostriction constant λ100 with opposite sign to that of Am. A two-sublattice model has been proposed to understand the intermediate region between the [111] and [110] spin configurations, which can also be used to explain the temperature dependence of magnetization.
基金funded by National Natural Science Foundation of China,(Grant Nos.11974030 and 92165208)。
文摘Electron spins confined in semiconductor quantum dots(QDs)are one of potential candidates for physical implementation of scalable quantum information processing technologies.Tunnel coupling based inter exchange interaction between QDs is crucial in achieving single-qubit manipulation,two-qubit gate,quantum communication and quantum simulation.This review first provides a theoretical perspective that surveys a general framework,including the Helter−London approach,the Hund−Mulliken approach,and the Hubbard model,to describe the inter exchange interactions between semiconductor quantum dots.An electrical method to control the inter exchange interaction in a realistic device is proposed as well.Then the significant achievements of inter exchange interaction in manipulating single qubits,achieving two-qubit gates,performing quantum communication and quantum simulation are reviewed.The last part is a summary of this review.
基金financially supported by the National Natural Science Foundation of China(No.11774045)the Joint Research Fund Liaoning-Shenyang National Laboratory for Materials Science(No.20180510008)the Fundamental Research Funds for Central Universities(Nos.N182410008-1 and N180506001)。
文摘When a ferromagnet(FM)couples to a spin glass(SG),the hidden nature of SG may imprint on the FM via their interfacial coupling,probably resulting in elongated magnetic relaxation and enhanced unidirectional and uniaxial anisotropies.In parallel with the study of interfacial roles,e.g.interfacial coupling and matching,we focused on the influence of the competing interactions in SG(JSG)on the magnetic relaxation properties of SG/FM bilayer and the FM magnetization reversal involving exchange bias field(HE)and coercivity(HC).A fastest decay of relaxation in SG/FM bilayer is found at an intermediate JSG^5.2 erg/cm2 and the relaxation parameters related to JSG are nonmonotonic.On the other hand,a pronounced HE of^0.26 kOe is observed at small JSG,and as JSG increases larger than 2.275 erg/cm2,HE decreases by an order of magnitude and levels off,i.e.,a net EB remains.He is sensitive to JSG only at JSG above 2.275 erg/cm2 and exhibits a minimum value at JSG=4.55 erg/cm2,just below 5.2 erg/cm2 where the relaxation decay is the fastest.Microscopic analysis unravels that the net magnetization associated with unidirectional magnetic stabilization and the large-area FM-like domains in SG are favored at small JSG,while with increasing JSG,the SG spins spontaneously reverse and thus the energy barriers are smeared out.A high susceptibility and a strong interfacial coupling lead to FM magnetization reversal under weaker fields and thus a decrease in coercivity.For too large JSG(exceeding 5.2 erg/cm2),magnetic frustration extends over the domains in SG meanwhile fierce energy competition occurs frequently,resembling enhanced quantum fluctuations.As a result,dynamic relaxation and statistic coercivity are both recovered.This work tells us that the independent modulations of unidirectional and uniaxial anisotropies are possible in SG-based systems through precisely controlling JSG,which is desired for application in the read/write head in future data storage media.
文摘Background:Musical perception requires a host of skills.Instrumental musicians place greater emphasis on motor coordination,whereas vocal musicians rehearse vocal sounds.The study explored the differential advantages of musical background on binaural integration and interaction in musicians(instrumentalists,vocalists)and compared them with age-matched non-musicians.Methods:Eight six participants aged 20e40 y with normal hearing sensitivity were subjected to binaural tests using a standard group comparison research design.The participants were segregated into three groups e Group 1 included instrumentalists(n?26,mean age:17.73±2.83 y),while Group 2 and Group 3 consisted of vocalists(n?30,mean age:19.30±2.47 y)and non-musicians(n?30,mean age:18.20±3.02 y)respectively.The binaural processes namely integration(Dichotic syllable test,DST;and virtual acoustic space identification-VASI)and interaction(Interaural difference thresholds for time and level:ITD&ILD),were administered on all the participants.Results:Statistical analyses showed the main effect of musicianship.Bonferroni pair-wise test revealed that the musicians(instrumentalists and vocalists)outperformed(p<0.05)non-musicians in all the tests.The differential advantage of the musical background was seen on the binaural integration test with instrumentalists performing better in the VASI test compared to vocalists,and vice-versa for DST.No difference was observed in interaction tasks(ITD&ILD)between vocalists and instrumentalists(p>0.05).Conclusion:Musical background-induced differential advantages can be reasonably noted in the binaural skills of instrumentalists and vocalists(compared to non-musicians).
文摘Taking α-Fe and Nd_2Fe_(14)B grains as example, the grain size dependence of the exchange-coupling interaction and effective anisotropy and also their variations depending on the ratio of magnetically soft and hard grain sizes, D_s∶D_h, were investigated. When grain size D>L_(ex), the grain’s anisotropy is the statistic value of the coupled and uncoupled part. The anisotropy constant of uncoupled part is the common value K_1 and that of coupled part varies with the distance to the grain surface. The effective anisotropy constant between magnetically soft and hard grains, K_(eff), can be expressed as the sum of the products of volume fractions for soft and hard grains, respectively, and the corresponding mean anisotropy constants. The calculation results indicate that the exchange-coupling interaction is enhanced with the reduction of grain size, and the effective anisotropy decreases with reducing grain size and increasing ratio of D_s∶D_h. In order to get high effective anisotropy constant, K_(eff), in composite magnetically soft-hard grains, the hard grain size should be larger than 30 nm and the soft grain size should be about 10 nm.
文摘The temperature dependence of lattice parameters a and c of intermetallic compounds RMn 2Ge 2(R=La, Sm and Gd)were measured in the temperature range of 10800 K by using the X-ray diffractometer . It is found that the high temperature magnetic transitions of Mn-subsystem in light rare earth compounds from paramagnetic to antiferromagnetic state accompany the negative magnetoelastic anomalies of lattice parameters c, where a does not change. This indicates that the antiferromagnetic component of intralayer Mn-Mn exchange coupling is correlated with lattice constant c. The low temperature first order ferromagnetism→antiferromagnetism transitions(or antiferromagnetism→ferromagnetism transition) of Mn-subsystem in SmMn 2Ge 2 and GdMn 2Ge 2 accompany the abruptly decrease(or increase) of lattice parameter a, and Δa/a≈0.15%. This demonstrates that the interlayer Mn-Mn exchange interaction is very sensitive to the intralayer Mn-Mn distance. The critical value of lattice constant a k, at which the interlayer Mn-Mn coupling changes its sign, is 4.044 5×10 -10 m. Based on the molecular field model of exchange interaction the magnetic curves of GdMn 2Ge 2 single crystal at different temperatures were calculated and a good agreement with experimental data had gotten. The Gd-Gd, Gd-Mn, intralayer Mn-Mn and interlayer Mn-Mn exchange coupling parameters were estimated.
基金Under the auspices of National Natural Science Foundation of China(No.40901026)Beijing Municipal Science & Technology New Star Project Funds(No.2010B046)+1 种基金Beijing Municipal Natural Science Foundation(No.8123041)Southwest Florida Water Management District(SFWMD) Project
文摘The commonly used discretization approaches for distributed hydrological models can be broadly categorized into four types,based on the nature of the discrete components:Regular Mesh,Triangular Irregular Networks(TINs),Representative Elementary Watershed(REWs) and Hydrologic Response Units(HRUs).In this paper,a new discretization approach for landforms that have similar hydrologic properties is developed and discussed here for the Integrated Hydrologic Model(IHM),a combining simulation of surface and groundwater processes,accounting for the interaction between the systems.The approach used in the IHM is to disaggregate basin parameters into discrete landforms that have similar hydrologic properties.These landforms may be impervious areas,related areas,areas with high or low clay or organic fractions,areas with significantly different depths-to-water-table,and areas with different types of land cover or different land uses.Incorporating discrete landforms within basins allows significant distributed parameter analysis,but requires an efficient computational structure.The IHM integration represents a new approach interpreting fluxes across the model interface and storages near the interface for transfer to the appropriate model component,accounting for the disparate discretization while rigidly maintaining mass conservation.The discretization approaches employed in IHM will provide some ideas and insights which are helpful to those researchers who have been working on the integrated models for surface-groundwater interaction.
