A model for sound lateralization.

Recent studies of multiple sclerosis (MS) and stroke patients suggested a correlation between two patterns of abnormal performance in lateralization tasks and two sites of pontine lesions. Most patients who had lesions below or at the superior olivary complex (SOC) perceived all interaural differences in binaural stimuli as small, while most patients who had lesions above the SOC perceived all interaural differences as large. The two abnormal performance patterns occurred for interaural time differences (ITD) and/or for interaural level differences (ILD). The present model proposes a multi-level hierarchical brainstem structure that estimates ITD and ILD. The first level seeks dissimilarity between the left and right inputs and a second level looks for similarity between the two sides' inputs. Each level is modeled as an ensemble of neural arrays in which each unit performs a logic or arithmetic function. The inputs are simulations of auditory nerve responses to broadband stimuli. Simulations yield good correspondence to the effect of both locations of pontine lesions on binaural performance.     

Tuning the tricritical point with spin-orbit coupling in polarized fermionic condensates

We investigate a two-component atomic Fermi gas with population imbalance in the presence of Rashba-type spin-orbit coupling (SOC). As a competition between SOC and population imbalance, the finite-temperature phase diagram reveals a large variety of new features, including the expanding of the superfluid state regime and the shrinking of both the phase separation and the normal regimes. For sufficiently strong SOC, the phase separation region disappears, giving way to the superfluid state. We find that the tricritical point moves toward a regime of low temperature, high magnetic field, and high polarization as the SOC increases.     

Generation and Manipulation of Spin-Orbit Coupling mode via Four-Wave Mixing with Quantum Interference

Recently, the vectorial nonlinear optical processes driven by spin-orbit coupling (SOC) light have come to the fore, leading to striking optical phenomena and important applications both in classical and quantum optics. However, research on the SOC-mediated light-atom interactions is still in its infancy. Here, the generation and manipulation of SOC mode through a vectorial four-wave mixing (FWM) process in ⁸⁵Rb vapor is demonstrated. Under the excitation of two SOC pump beams, multiple FWM paths can be simultaneously established due to the rich atomic Zeeman sublevels coupling with different circularly polarized components of SOC fields. A higher-order cylindrical or more general SOC FWM signal is observed in the vectorial FWM process, which obeys angular momentum conservation and Gouy phase matching. In particular, quantum interference between different FWM paths plays a crucial role in manipulating the SOC mode of the generated FWM signal, revealing that the conversion of SOC mode is intrinsically quantum. This work provides a pathway toward deeper insight into the vectorial nonlinear optical processes and may advance technology for shaping spatially structured light, which is essential in applications such as nonlinear polarization imaging and the optical communication realm.     

X-ray absorption spectroscopy studies of spin-orbit coupling in 5d transition metal oxides

In order to examine the effects of strong valence band spin-orbit coupling (SOC) in 5d transition metal oxides (TMOs), we have investigated the L(2) and L(3) edge white-line intensities of the x-ray absorption spectra of several 5d TMOs. The white-line intensities at both edges are found to decrease monotonously with increasing 5d electron occupancy, while their ratio showed anomalous behavior for late 5d TMOs (IrO(2), PtO(2), and Au(2)O(3)), deviating significantly from the theoretical value of 2 expected for the case of weak SOC. This observation serves as a clear experimental indication of strong SOC effects in 5d TMOs. We also discussed how the 5d TMOs can have charge transfer effects different from their counterpart 5d elemental metals by making comparative studies. Our works demonstrate the importance of j quantum states due to strong SOC in the 5d system.     

State of charge estimation of Li-ion batteries in an electric vehicle based on a radial-basis-function neural network

The on-line estimation of the state of charge(SOC) of the batteries is important for the reliable running of the pure electric vehicle in practice.Because a nonlinear feature exists in the batteries and the radial-basis-function neural network(RBF NN) has good characteristics to solve the nonlinear problem,a practical method for the SOC estimation of batteries based on the RBF NN with a small number of input variables and a simplified structure is proposed.Firstly,in this paper,the model of on-line SOC estimation with the RBF NN is set.Secondly,four important factors for estimating the SOC are confirmed based on the contribution analysis method,which simplifies the input variables of the RBF NN and enhances the real-time performance of estimation.Finally,the pure electric buses with LiFePO 4 Li-ion batteries running during the period of the 2010 Shanghai World Expo are considered as the experimental object.The performance of the SOC estimation is validated and evaluated by the battery data from the electric vehicle.     

Resistivity Relaxation of Anisotropic Conductive Polymer Composites

The electrical properties of anisotropic carbon nanotubes (CNTs)/polycarbonate (PC)/ polyethylene (PE) (ACPC) strongly depended on the CNTs’ concentration. When the ACPC was subjected to isothermal treatment (IT), the resistivity variation in both the parallel and perpendicular directions had the characteristics of a relaxation as a function of temperature. During the IT the orientation of the PC microfibrils was gradually damaged and CNTs/PC microfibrils were deformed and changed to short fibers, leading to a transition from anisotropy to isotropy. The velocity of the conductive network reconstruction could be characterized by the relaxation time, and the resistivity of the composite during the IT process can be instantaneously predicted based on the relaxation equation. The relaxation time and the equilibrium resistivity of the composite during IT were determined by the IT temperature and CNT content.     

Spin inverter and polarizer curved nanowire driven by Rashba and Dresselhaus spin–orbit interactions

We propose in theory a curved nanowire structure that can both serve as a spin inverter and a spin polarizer driven by a periodic Rashba spin–orbit coupling (SOC) and a uniform Dresselhaus SOC. The curved section of the U-shaped quasi-one dimensional nanowire with an arc of radius R and circumferential length $\pi R$ is divided into segments of equal length initially having only its inherent homogeneous Dresselhaus SOC. Then a Rashba-type SOC is applied at every alternating segment. By tuning the Rashba SOC strength and the incident electron energy, this device can flip the spin at the output of an incoming spin-polarized electron. On the other hand, this same device acts as a spin filter for an unpolarized input for which an outgoing electron with a non-zero polarization can be achieved without the application of an external magnetic field. Moreover, the potential modulation caused by the periodic Rashba SOC enables this device to function as an attenuator for a certain range of incident electron energies that can make the probability current density drop to 10⁻⁴ of its otherwise magnitude in other regimes.     

金属表面Rashba自旋轨道耦合作用研究进展

自旋轨道耦合是电子自旋与轨道相互作用的桥梁, 它提供了利用外电场来调控电子的轨道运动、进而调控电子自旋状态的可能. 固体材料中有很多有趣的物理现象, 例如磁晶各向异性、自旋霍尔效应、拓扑绝缘体等, 都与自旋轨道耦合密切相关. 在表面/界面体系中, 由于结构反演不对称导致的自旋轨道耦合称为Rashba自旋轨道耦合, 它最早在半导体材料中获得研究, 并因其强度可由栅电压灵活调控而备受关注, 成为电控磁性的重要物理基础之一. 继半导体材料后, 金属表面成为具有Rashba自旋轨道耦合作用的又一主流体系. 本文以Au(111), Bi(111), Gd(0001)等为例综述了磁性与非磁性金属表面Rashba自旋轨道耦合的研究进展, 讨论了表面电势梯度、原子序数、表面态波函数的对称性, 以及表面态中轨道杂化等因素对金属表面Rashba自旋轨道耦合强度的影响. 在磁性金属表面, 同时存在Rashba自旋轨道耦合作用与磁交换作用, 通过Rashba自旋轨道耦合可能实现电场对磁性的调控. 最后, 阐述了外加电场和表面吸附等方法对金属表面Rashba自旋轨道耦合的调控. 基于密度泛函理论的第一性原理计算和角分辨光电子能谱测量是金属表面Rashba自旋轨道耦合的两大主要研究方法, 本文综述了这两方面的研究结果, 对金属表面Rashba自旋轨道耦合进行了深入全面的总结和分析.     

Shot Noise in Aharonov-Casher Rings

We investigate the shot noise of electron transport through an Aharonov-Casher ring subject to the Rashba spin-orbit coupling （SOC）. Analytic expressions for the coefficients of reflection and transmission are derived by using the Griffith boundary conditions. For this kind of SOC, the ballistic transport of electrons can be analyzed as two independent spin channels, and both of them have the same transmission and reflection coefficients. The dependences of shot noise and Landauer-Biittiker conductance on controllable factors, including the strength of Rashba SOC, the asymmetrical angle of lead-connection positions, the radius of the rings, and the wave vector （or energy） of the incident Fermi electrons, are explicitly described by some new combined parameters. The ways that the shot noise and conductance vary with Rashba SOC and with asymmetrical angle are demonstrated by numerical simulations, respectively. It is revealed that the shot noise reaches its maximum for the particular situation of half transmission and half reflection and zero shot noise occurs at conductance maxima.     

东北黑土不同组分有机碳的近红外光谱测定

不同颗粒组分的土壤有机碳(soil organic carbon,SOC)具有不同的化学组成且对不同农艺措施响应不同,因此了解其信息有助于深入理解SOC对土壤肥力的贡献。本研究旨在评价近红外光谱(near Infraredspectroscopy,NIRS)预测黑土不同颗粒组分SOC(水稳性团聚体结合碳、颗粒态有机碳及不同大小粒级有机碳)的潜力。土壤样品(n=136)采集于东北典型黑土带上,利用偏最小二乘法建立定量模型(n=100),并用独立样本对模型进行检验(n=36)。结果表明:NIRS可以在一定程度上预测水稳性团聚体结合碳含量(R2=0.69-0.82,RPD=1.2-1.8);对矿质结合态SOC(<53μm)(R2=0.97,RPD=5.4)及细粒级SOC(<20μm)(R2=0.93,RPD=3.8)预测结果较好,对颗粒态有机碳(>53μm)和粗粒级SOC(>20μm)预测结果不理想。NIRS在简化黑土不同颗粒组分SOC的测定,特别是矿质结合态(<53μm)SOC,具有很好的应用前景。     

Electronic structure of quantum spheres and quantum wires

The electronic structures of quantum spheres and quantum wires are studied in the framework of the effective-mass theory. The spin-orbital coupling (SOC) effect is taken into account. On the basis of the zero SOC limit and strong SOC limit the hole quantum energy levels as functions of SOC parameter λ are obtained. There is a fan region in which the ground and low-lying excited states approach those in the strong SOC limit as λ increases. Besides, some theoretical results on the corrugated superlattices (CSL) are given.     

双包络去除和OPLS的土壤有机碳含量反演

土壤有机碳(SOC)对土壤肥力至关重要,可见-近红外光谱能对其实现快速反演,为区域监测和定量遥感提供基础。针对包络去除(CR)仅提供反射光谱的单向吸收特征,多元回归中预测信息缺失、拟合结果未充分反映波段特征,利用世界土壤数据库245份中国土样的可见-近红外光谱,首次提出双包络去除(BCR)与正交偏最小二乘(OPLS)结合的反演方法BCR-OPLS,同时纳入光谱反射率及上、下边包络去除量,讨论组分参考值偏态分布时幂函数或对数缩放在回归时的优化作用,建立多种土壤的综合与分类估计模型,并导出适用特定类型土壤的SOC指数。结果表明,对多种土壤有机碳含量反演,相较PLSR模型(决定系数R2和估计根均方误差RMSEE分别为0.69和0.45%),BCR-OPLS模型的预测能力明显改善(R2和RMSEE分别为0.9和0.26%);而对单一类型土壤的反演精度则进一步提升,根据载荷趋势和变量重要性建立的SOC指数,预测如黄色铁铝土的有机碳含量时(以400,590和920 nm),其反演结果R2达到0.94、RMSEE达到0.21%。双包络去除与OPLS相结合,增强了光谱特征诊断的鲁棒性,提高了不同类型土壤的综合与分类SOC全谱反演精度,基于直观的图谱表达可构建简单的波段预测关系,深化了物理经验吸收与统计多元回归之间的联系。     

Chaotic Cyclotron and Hall Trajectories Due to Spin-Orbit Coupling

It is demonstrated that the synergistic effect of a gauge field, Rashba spin-orbit coupling (SOC), and Zeeman splitting can generate chaotic cyclotron and Hall trajectories of particles. The physical origin of the chaotic behavior is that the SOC produces a spin-dependent (so-called anomalous) contribution to the particle velocity and the presence of Zeeman field reduces the number of integrals of motion. By using analytical and numerical arguments, the conditions of chaos emergence are studied and the dynamics both in the regular and chaotic regimes is reported. The critical dependence of the dynamic patterns (such as the chaotic regime onset) on small variations in the initial conditions and problem parameters, that is the SOC and/or Zeeman constants, is observed. The transition to chaotic regime is further verified by the analysis of phase portraits as well as Lyapunov exponents spectrum. The considered chaotic behavior can occur in solid state systems, weakly relativistic plasmas, and cold atomic gases with synthetic gauge fields and spin-related couplings.     

Subsampling effects in neuronal avalanche distributions recorded in vivo

Background  

Many systems in nature are characterized by complex behaviour where large cascades of events, or avalanches, unpredictably alternate with periods of little activity. Snow avalanches are an example. Often the size distribution f(s) of a system's avalanches follows a power law, and the branching parameter sigma, the average number of events triggered by a single preceding event, is unity. A power law for f(s), and sigma = 1, are hallmark features of self-organized critical (SOC) systems, and both have been found for neuronal activity in vitro. Therefore, and since SOC systems and neuronal activity both show large variability, long-term stability and memory capabilities, SOC has been proposed to govern neuronal dynamics in vivo. Testing this hypothesis is difficult because neuronal activity is spatially or temporally subsampled, while theories of SOC systems assume full sampling. To close this gap, we investigated how subsampling affects f(s) and sigma by imposing subsampling on three different SOC models. We then compared f(s) and sigma of the subsampled models with those of multielectrode local field potential (LFP) activity recorded in three macaque monkeys performing a short term memory task.     

Spin and spin-orbit coupling effects in nickel-based superalloys: A first-principles study on Ni3Al doped with Ta/W/Re

Heavy elements(X=Ta/W/Re)play an important role in the performance of superalloys,which enhance the strength,anti-oxidation,creep resistance,and anti-corrosiveness of alloy materials in a high-temperature environment.In the present research,the heavy element doping effects in FCC-Ni(γ)and Ni₃Al(γ')systems are investigated in terms of their thermodynamic and mechanical properties,as well as electronic structures.The lattice constant,bulk modulus,elastic constant,and dopant formation energy in non-spin,spin polarized,and spin-orbit coupling(SOC)calculations are compared.The results show that the SOC effects are important in accurate electronic structure calculations for alloys with heavy elements.We find that including spin for bothγandγ'phases is necessary and sufficient for most cases,but the dopant formation energy is sensitive to different spin effects,for instance,in the absence of SOC,even spin-polarized calculations give 1%to 9%variance in the dopant formation energy in our model.Electronic structures calculations indicate that spin polarization causes a split in the metal d states,and SOC introduces a variance in the spin-up and spin-down states of the d states of heavy metals and reduces the magnetic moment of the system.     

Opposite effect of spin-orbit coupling on condensation and superfluidity

We investigate the effects of Rashba-type spin-orbit coupling (SOC) on the condensed density and superfluid density tensor of a two-component Fermi gas in the BCS-BEC crossover at zero temperature. In anisotropic three dimensions (3D), we find that SOC has an opposite effect on condensation (enhanced) and superfluidity (suppressed in the SOC direction), and this effect becomes most pronounced for very weak interactions and the SOC strength being larger than a characteristic value. Furthermore, as functions of SOC strength, the condensed density changes monotonically for all interaction parameters, while the superfluid density has a minimum when the interaction parameter is below a critical value. We also discuss the isotropic two-dimensional case where analytical expressions for the gap and number equations are obtained and the same phenomena are found as that of the 3D case.     

Asymmetric Fraunhofer pattern in Josephson junctions from heterodimensional superlattice V5S8

Introduction of spin-orbit coupling (SOC) in a Josephson junction (JJ) gives rise to unusual Josephson effects. We investigate JJs based on a newly discovered heterodimensional superlattice V₅S₈ with a special form of SOC. The unique homointerface of our JJs enables elimination of extrinsic effects due to interfaces and disorder. We observe asymmetric Fraunhofer patterns with respect to both the perpendicular magnetic field and the current. The asymmetry is influenced by an in-plane magnetic field. Analysis of the pattern points to a nontrivial spatial distribution of the Josephson current that is intrinsic to the SOC in V₅S₈.     

Fading analysis of the Li(NiCoMn)O<Subscript>2</Subscript> battery under different SOC cycle intervals

In a review of literature on operating conditions, such as temperature, materials, cutoff voltage, and current rate, state-of-charge (SOC) interval has attracted less attention regarding research on cell fading. Lithium-ion cells as power source practically applied to electric vehicles (EVs) are seldom operated in the entire SOC interval, which means that lithium-ion cells are employed in a certain SOC interval. However, the SOC interval that facilitates the increase of the life span of the cell remains unknown. In the current study, several cells are tested over different SOC intervals and discharge rates. In-depth analysis is performed on the influence of the two factors on cell fading. The incremental capacity and incremental resistance methods are used to analyze capacity fading and resistance evolution. The electrochemical mechanism analysis of cell fading is studied and discussed, showing that SOC interval influences the rate of cell degradation. Results show that a low SOC interval prolongs the life span of cell use if other operating conditions are similar. Therefore, the study provides a theoretical framework and reference for the cell maintenance of EVs.     

基于等效模型和多时间尺度扩展卡尔曼滤波的锂离子电池SOC预测

荷电状态(SOC)和最大可用电量估计是锂离子电池寿命预测中的两个最重要部分;然而与快速时变的SOC比较,最大可用电量的参数变化缓慢;文章提出了一个基于等效模型和多时间尺度的扩展卡尔曼滤波(EKF)预测算法对SOC和最大可用容量分别在不同时间尺度上进行估计,在宏观尺度上利用了SOC估计值作为观测量,更新最大可用电量;针对NCA/C卫星锂离子电池实验数据的仿真结果表明,提出的多时间尺度EKF预测算法与EKF联合估计算法相比,SOC和最大可用电量估计准确度更高,同时提高了计算效率。     

Analysis of refractometric fiber optic state-of-charge (SOC) monitoring sensor for lead acid battery

In situ monitoring of the state of charge (SOC) of lead acid battery is important to understand the residual electrical energy. Usage of battery reduces the charge content of the active electrolyte which in turn changes its refractive index. This paper reports refractometric fiber optic sensor developed for on-line monitoring of SOC. The SOC is monitored during discharging phases of the battery using the developed fiber optic sensor probe along with terminal voltage, temperature and depth of discharge using a LABVIEW based data acquisition system. The paper gives the working principle, design and construction details, results and calibration of the fiber optic sensor (FOS) probe. The in situ monitoring capability of the developed FOS is demonstrated in comparison with the contemporary off-line methods of specific gravity and terminal voltage measurements.