Study on the Evolution of Plane Shape of Guangfu Ancestral Hall Buildings and the Construction of Type Genealogy in the Ming and Qing Dynasties

This paper studies the clan temples in four periods,namely,the development period(early Ming Dynasty and before),the shaping period(mid-Ming Dynasty to early Qing Dynasty),the maturity period(mid-Qing Dynasty),and the programmed period(late Qing Dynasty),analyzes and summarizes their prototypical planform features and attempts to summarize and construct a genealogy of the architectural characteristics of the plane shape of clan temples.During the Ming and Qing dynasties,Guangfu ancestral halls in general showed a journey of development from a centripetal-single-linear-multi-linear-grid pattern,forming the unique Guangsanlu classic pattern in the Guangfu area.

Study on the Influencing Factors and Mechanisms of the Evolution of the Architectural Characteristics of Guangfu Ancestral Halls in the Ming and Qing Dynasties

This paper discusses ancestral hall architecture within the context of the Cantonese folk lineage in the Pearl River Delta.Using a typological research approach and chronological analysis,various factors that have influenced the evolution of ancestral hall architecture are analyzed.The study specifically investigates the features of ancestral halls during the Ming and Qing dynasties.Three periods of ancient China are analyzed:The transition from Ming to Qing,the mid-Qing dynasty,and the late Qing dynasty.The variables of each period and how they influence the evolution of architectural typological features are identified.Based on our analysis,architectural features are related to economic and social factors,materials available,and craftsmanship of the construction workers.

Hall技术治疗乳磨牙龋的临床疗效观察

目的:通过队列研究观察用Hall技术治疗乳磨牙龋的临床疗效,探讨影响成功率的因素。方法:选择2020年3月至2022年6月就诊的乳磨牙龋患者31例(31颗患牙),用Hall技术治疗。术后12~39个月复查,通过颞下颌关节和治疗牙有无症状、临床检查和根尖X线片进行疗效评价。采用Kaplan-Meier生存分析统计成功率,Log-Rank检验分析不同因素对成功率的影响。结果:30例患者[年龄(4.9±1.5)岁(3.3~8.2岁),男21例,女9例]接受了12个月以上复查,总体成功率是93.3%;术后1年和2年的累积生存概率是96.7%和92.3%。年龄、牙位、洞形和ICDAS冠部龋影像学检查编码等因素对成功率均无统计学意义(P>0.05)。结论:用Hall技术治疗乳磨牙龋可获得良好疗效,年龄、牙位、洞形和龋坏深度等因素不影响成功率。

基于Hall和GMR的多传感器融合方法及实现

目前霍尔传感器(Hall)和巨磁阻(GMR)传感器均广泛地应用于电力系统电流测量。为同时发挥二者的优势、降低各自的局限性,在分析Hall和GMR的温度特性、噪声特性和被测电流范围的基础上,提出了一种基于Hall和GMR的多传感器融合方案。在定义GMR和Hall的灵敏度差值ΔS基础上,将被测电流i和灵敏度差值ΔS构成的融合域划分为四个域,在域Ⅱ采用多传感加权观测融合Kalman滤波算法,将Hall和GMR的观测量和观测噪声融合后与状态方程联立进行Kalman滤波;在域Ⅰ采用数据加权融合最优权值分配的方法,给Hall的测量数据赋予较大权值,GMR的测量数据赋予较小的权值;在域Ⅲ,权值分配情况相反,各域之间可实现数据融合的平滑过渡。基于多传感器融合方法,设计了一种组合式闭环电流传感器,包括磁芯、电路部分设计及仿真。仿真和样机实验结果表明,在域Ⅱ时多传感器融合值与真实值的均方根误差低至0.004;在域Ⅰ、Ⅲ时电流测量的相对误差E_(i)均在0.255%以下。与单一传感器相比,多传感器融合的方法使组合式传感器测量电流范围增大,适用于温度变化范围较大的场景,电流测量精度及可信度更高。

Influence of the position relationship between the cathode and magnetic separatrix on the discharge process of a Hall thruster

Previous studies have shown that there is an obvious coupling relationship between the installation location of the external cathode and the magnetic separatrix in the plume region of a Hall thruster.In this paper,the particle-in-cell simulation method is used to compare the thruster discharge process under the conditions of different position relationships between the cathode and the magnetic separatrix.By comparing the distribution of electron conduction,potential,plasma density and other microscopic parameters,we try to explain the formation mechanism of the discharge difference.The simulation results show that the cathode inside and outside the magnetic separatrix has a significant effect on the distribution of potential and plasma density.When the cathode is located on the outer side of the magnetic separatrix,the potential above the plume region is relatively low,and there is a strong potential gradient above the plume region.This potential gradient is more conducive to the radial diffusion of ions above the plume,which is the main reason for the strong divergence of the plume.The distribution of ion density is also consistent with the distribution of potential.When the cathode is located on the outer side of the magnetic separatrix,the radial diffusion of ions in the plume region is enhanced.Meanwhile,by comparing the results of electron conduction,it is found that the traiectories of electrons emitted from the cathode are significantly different between the inner and outer sides of the magnetic separatrix.This is mainly because the electrons are affected by the magnetic mirror effect of the magnetic tip,which makes it difficult for the electrons to move across the magnetic separatrix.This is the main reason for the difference in potential distribution.In this paper,the simulation results of macroscopic parameters under several conditions are also compared,and they are consistent with the experimental results.The cathode is located on the inner side of the magnetic separatrix,which can effectively reduce the plume divergence angle and improve the thrust.In this paper,the cathode moves from R=50 mm to R=35 mm along the radial direction,the thrust increases by 3.6 mN and the plume divergence angle decreases by 23.77%.Combined with the comparison of the ionization region and the peak ion density,it is found that the main reason for the change in thrust is the change in the radial diffusion of ions in the plume region.

Enhanced anomalous Hall effect in kagome magnet YbMn_(6)Sn_(6)with intermediate-valence ytterbium

We report on the magnetization and anomalous Hall effect(AHE)in the high-quality single crystals of the kagome magnet YbMn_(6)Sn_(6),where the spins of the Mn atoms in the kagome lattice order ferromagnetically and the intermediate-valence Yb atoms are nonmagnetic.The intrinsic mechanism plays a crucial role in the AHE,leading to an enhanced anomalous Hall conductivity(AHC)compared with the other rare-earth RMn_(6)Sn_(6)compounds.Our band structure calculation reveals a strong hybridization between the 4f electrons of Yb and conduction electrons.

Anomalous valley Hall effect in two-dimensional valleytronic materials

The anomalous valley Hall effect(AVHE)can be used to explore and utilize valley degrees of freedom in materials,which has potential applications in fields such as information storage,quantum computing and optoelectronics.AVHE exists in two-dimensional(2D)materials possessing valley polarization(VP),and such 2D materials usually belong to the hexagonal honeycomb lattice.Therefore,it is necessary to achieve valleytronic materials with VP that are more readily to be synthesized and applicated experimentally.In this topical review,we introduce recent developments on realizing VP as well as AVHE through different methods,i.e.,doping transition metal atoms,building ferrovalley heterostructures and searching for ferrovalley materials.Moreover,2D ferrovalley systems under external modulation are also discussed.2D valleytronic materials with AVHE demonstrate excellent performance and potential applications,which offer the possibility of realizing novel low-energy-consuming devices,facilitating further development of device technology,realizing miniaturization and enhancing functionality of them.

Growth mechanism and characteristics of electron drift instability in Hall thruster with different propellant types

The existence of a significant electron drift instability(EDI) in the Hall thruster is considered as one of the possible causes of the abnormal increase in axial electron mobility near the outlet of the channel. In recent years, extensive simulation research on the characteristics of EDI has been conducted, but the excitation mechanism and growth mechanism of EDI in linear stage and nonlinear stage remain unclear. In this work, a one-dimensional PIC model in the azimuthal direction of the thruster near-exit region is established to gain further insights into the mechanism of the EDI in detail, and the effects of different types of propellants on EDI characteristics are discussed. The changes in axial electron transport caused by EDI under different types of propellants and electromagnetic field strengths are also examined. The results indicate that EDI undergoes a short linear growth phase before transitioning to the nonlinear phase and finally reaching saturation through the ion Landau damping. The EDI drives a significant ion heating in the azimuthal direction through electron–ion friction before entering the quasi-steady state, which increases the axial mobility of the electrons. Using lighter atomic weight propellant can effectively suppress the oscillation amplitude of EDI, but it will increase the linear growth rate, frequency, and phase velocity of EDI. Compared with the classical mobility, the axial electron mobility under the EDI increases by three orders of magnitude, which is consistent with experimental phenomena. The change of propellant type is insufficient to significantly change the axial electron mobility. It is also found that the collisions between electrons and neutral gasescan significantly affect the axial electron mobility under the influence of EDI, and lead the strength of the electric field to increase and the strength of the magnetic field to decrease, thereby both effectively suppressing the axial transport of electrons.

Spin direction dependent quantum anomalous Hall effect in two-dimensional ferromagnetic materials

We propose a scheme for realizing the spin direction-dependent quantum anomalous Hall effect(QAHE)driven by spin-orbit couplings(SOC)in two-dimensional(2D)materials.Based on the sp^(3)tight-binding(TB)model,we find that these systems can exhibit a QAHE with out-of-plane and in-plane magnetization for the weak and strong SOC,respectively,in which the mechanism of quantum transition is mainly driven by the band inversion of p_(x,y)/p_(z)orbitals.As a concrete example,based on first-principles calculations,we realize a real material of monolayer 1T-SnN_(2)/PbN_(2)exhibiting the QAHE with in-plane/out-of-plane magnetization characterized by the nonzero Chern number C and topological edge states.These findings provide useful guidance for the pursuit of a spin direction-dependent QAHE and hence stimulate immediate experimental interest.

Discovery of controllable high Chern number quantum anomalous Hall state in tetragonal lattice FeSIn

Quantum anomalous Hall(QAH) insulators have excellent properties driven by fancy topological physics, but their practical application is greatly hindered by the observed temperature of liquid nitrogen, and the QAH insulator with high Chern number is conducive to spintronic devices with lower energy consumption. Here, we find that monolayer Fe SIn is a good candidate for realizing the QAH phase;it exhibits a high magnetic transition temperature of 221 K and tunable C = ±2 with respect to magnetization orientation in the y–z plane. After the application of biaxial strain, the magnetic axis shifts from the x–y plane to the z direction, and the effect of the high C and ferromagnetic ground state on the stress is robust. Also, the effect of correlation U on C has been examined. These properties are rooted in the large size of the Fe atom that contributes to ferromagnetic kinetic exchange with neighboring Fe atoms. These findings demonstrate monolayer Fe SIn to be a major template for probing novel QAH devices at higher temperatures.

Relationship of Edge States to Anomaly and Construction of Dual Systems in Quantum Hall Systems

The hierarchy of bulk actions is developed which are associated with Chern-Simons theories. The connection between the bulk and edge arising from the requirement there is a cancelation of an anomaly which arises in the theory. A duality transformation is studied for the Chern-Simons example. The idea that is used has been employed to describe duality in a scalar theory. The link between the edge theory with the Chern-Simons theory in the bulk then suggests that similar transformations can be implemented in the bulk Chern-Simons theory as well.

三维Hall-magnetohydrodynamic方程的整体小解

该文研究R^(3)上的不可压缩的带霍尔效应的磁流体力学方程的Cauchy问题.假设初始速度的水平分量或水平分量的和及初始磁场的B˙_(2,1)^(1/2)范数充分小,该文证明了该方程存在整体光滑解,改进了Chae和Lee(J.Differ.Equ.2014,256:3835-3858)的结果.

Hall曲线在气田水回注环境风险预警中的应用

目的为有效控制气田水回注泄漏风险,将地下水污染环境风险防控关口前置。方法结合回注井日常运行参数,建立了回注井Hall曲线关系,利用回注井累积注入量与Hall积分(注入压差×累计时间)的线性关系,监测回注异常工况,并应用微地震监测技术进行结果验证。结果应用Hall曲线能更为简便直观地对回注井进行跟踪监测,消除单次注水参数变化等带来的影响,在气田水回注井地下水常规监测的基础上实现回注风险的提前预警,提高气田水回注井泄漏监测的准确性和科学性,为下一步回注井地下水环境风险预警奠定基础。结论气田水回注应进一步建立完善以气田水回注井完整性管理为核心的地下水环境风险防控体系。

基于Sage-Husa预测算法的直流无刷电机Hall传感器位置信息校正

直流无刷电机控制需要转子位置信息,位置信息识别偏差会降低电机效率。本文以带有开关型Hall传感器的直流无刷电机为研究对象,基于最小偏差原则,估算了Hall传感器间的相对安装偏移,明确了基于LBEMF的电机理想换相位置识别方法,消除了Hall传感器安装位置偏差,采用预标定方法,推算了信号调理电路引入的延迟,并提出了一种转子位置信息校正策略;设计了一种基于Sage-Husa法的自适应位置信息预测算法,滤除预标定未能消除的位置信息偏差。在氢气循环泵实验平台的结果表明,采用预标定方法后,转速波动MAPE降低了72.4%,平均相电流降低了62.8%,系统效率明显提高;相对于传统KF预测算法,本文预测算法的匀速与调速阶段转速波动、转速曲线超调及全过程换相时间波动分别降低了16.0%、19.4%、42.1%及35.0%,具有更高的抗扰动能力,对换相时刻的预测更准确稳定。

对比传统窝洞充填术与改良Hall技术治疗儿童乳磨牙龋病疗效的研究

目的:分析对比传统窝洞充填术与改良Hall技术在儿童乳磨牙龋病中的治疗效果。方法:选取2021年1月—2022年1月本院收治的150例患儿(150颗牙),按随机数字表法划分成两组,均75例。对照组给予传统窝洞充填术治疗,观察组予以改良Hall技术治疗,观察到术后12个月。对比两组修复效果、并发症、满意度。结果:观察组修复总有效率为97.33%(73/75)、满意度为94.67%(71/75),高于对照组的88.00%(66/75)、84.00%(63/75),并发症发生率为4.00%(3/75),低于对照组的13.33%(10/75),有统计学差异(P<0.05)。结论:与传统窝洞充填术相比,改良Hall技术治疗乳磨牙龋病患儿效果更为显著,能够改善修复效果,减少并发症的发生,继而提升患儿与其家属的满意度,具有较高的临床运用价值。

Vectorial spin-orbital Hall effect of light upon tight focusing and its experimental observation in azopolymer films

Hall effect of light is a result of symmetry breaking in spin and/or orbital angular momentum(OAM)possessing optical system and is caused by e.g.refractive index gradient/interface between media or focusing of a spatially asymmetrical beam,similar to the electric field breaking the symmetry in spin Hall effect for electrons.The angular momentum(AM)conservation law in the ensuing asymmetric system dictates redistribution of spin and orbital angular momentum,and is manifested in spin-orbit,orbit-orbit,and orbit-spin conversions and reorganization,i.e.spin-orbit and orbit-orbit interaction.This AM restructuring in turn requires shifts of the barycenter of the electric field of light.In the present study we show,both analytically and by numerical simulation,how different electric field components are displaced upon tight focusing of an asymmetric light beam having OAM and spin.The relation between field components shifts and the AM components shifts/redistribution is presented too.Moreover,we experimentally demonstrate,for the first time,to the best of our knowledge,the spin-orbit Hall effect of light upon tight focusing in free space.This is achieved using azopolymers as a media detecting longitudinal or z component of the electrical field of light.These findings elucidate the Hall effect of light and may broaden the spectrum of its applications.

Phase transition in bilayer quantum Hall system with opposite magnetic field

We construct a mapped bilayer quantum Hall system to realize the proposal that two nearly flatbands have opposite Chern numbers.For the C=±1 case,the two Landau levels of the bilayer experience opposite magnetic fields.We consider a mapped bilayer quantum Hall system at total fillingν_(t)=1/2+1/2where the intralayer interaction is repulsive and the interlayer interaction is attractive.We take exact diagonalization(ED)calculations on a torus to study the phase transition when the separation distance d/l_(B)is driven.The critical point at d_(c)/l_(B)=0.68 is characterized by a collapse of degeneracy and a crossing of energy levels.In the region d/l_(B)<d_(c)/l_(B),the states of each level are highly degenerate.The pair-correlation function indicates electrons with opposite pseudo-spins are strong correlated at r=0.We find an exciton stripe phase composed of bound pairs.The ferromagnetic ground state is destroyed by the strong effective attractive potential.An electron composite-Fermion(eCF)and a hole composite Fermion(hCF)are tightly bound.In the region d/lB>d_(c)/l_(B),a crossover from the d→d_(c)limit to the large d limit is observed.The electron and hole composite Fermion liquids(CFL)are realized by composite Fermions(CF)which attach opposite fluxes,respectively.

Thermal Hall effect and the Wiedemann–Franz law in Chern insulator

Thermal Hall effect, where a transverse temperature difference is generated by implementing a longitudinal temperature gradient and an external magnetic field in the perpendicular direction to systems, is a useful tool to reveal transport properties of quantum materials. A systematic study of the thermal Hall effect in a Chern insulator is still lacking. Here,using the Landauer–Büttiker formula, we investigated the thermal Hall transport of the Harper–Hofstadter model with flux φ= 1/2 and its generalizations. We demonstrated that the Wiedemann–Franz law, which states that the thermal Hall conductivity is linearly proportional to the quantum Hall conductivity in the low temperature limit, is still valid in this Chern insulator, and that the thermal Hall conductivity can be used to characterize the topological properties of quantum materials.

Hall conductance of a non-Hermitian two-band system with k-dependent decay rates

Two-band model works well for Hall effect in topological insulators. It turns out to be non-Hermitian when the system is subjected to environments, and its topology characterized by Chern numbers has received extensive studies in the past decades. However, how a non-Hermitian system responses to an electric field and what is the connection of the response to the Chern number defined via the non-Hermitian Hamiltonian remains barely explored. In this paper, focusing on a k-dependent decay rate, we address this issue by studying the response of such a non-Hermitian Chern insulator to an external electric field. To this aim, we first derive an effective non-Hermitian Hamiltonian to describe the system and give a specific form of k-dependent decay rate. Then we calculate the response of the non-Hermitian system to a constant electric field.We observe that the environment leads the Hall conductance to be a weighted integration of curvature of the ground band and hence the conductance is no longer quantized in general. And the environment induces a delay in the response of the system to the electric field. A discussion on the validity of the non-Hermitian model compared with the master equation description is also presented.

Recent progress on the planar Hall effect in quantum materials

The planar Hall effect(PHE),which originates from anisotropic magnetoresistance,presents a qualitative and simple approach to characterize electronic structures of quantum materials by applying an in-plane rotating magnetic field to induce identical oscillations in both longitudinal and transverse resistances.In this review,we focus on the recent research on the PHE in various quantum materials,including ferromagnetic materials,topological insulators,Weyl semimetals,and orbital anisotropic matters.Firstly,we briefly introduce the family of Hall effect and give a basic deduction of PHE formula with the second-order resistance tensor,showing the mechanism of the characteristicπ-period oscillation in trigonometric function form with aπ/4 phase delay between the longitudinal and transverse resistances.Then,we will introduce the four main mechanisms to realize PHE in quantum materials.After that,the origin of the anomalous planar Hall effect(APHE)results,of which the curve shapes deviate from that of PHE,will be reviewed and discussed.Finally,the challenges and prospects for this field of study are discussed.