Double exchange, itinerant ferromagnetism and topological Hall effect in moir\'{e} heterobilayer

Motivated by the recent experiments and the wide tunability on the MoTe$_2$/WSe$_2$ moir\'{e} heterobilayer, we consider a physical model to explore the underlying physics for the interplay between the itinerant carriers and the local magnetic moments. In the regime where the MoTe$_2$ is tuned to a triangular lattice Mott insulator and the WSe$_2$ layer is doped with the itinerant holes, we invoke the itinerant ferromagnetism from the double exchange mechanism for the itinerant holes on the WSe$_2$ layer and the local moments on the MoTe$_2$ layer. Together with the antiferromagnetic exchange on the MoTe$_2$ layer, the itinerant ferromagnetism generates the scalar spin chirality distribution in the system. We further point out the presence of spin-assisted hopping in addition to the Kondo coupling between the local spin and the itinerant holes, and demonstrate the topological Hall effect for the itinerant electrons in the presence of the non-collinear spin configurations. This work may improve our understanding of the correlated moir\'{e} systems and inspire further experimental efforts

Numerical analysis of the flow mechanism and axial force characteristics of the cavity in a centrifugal pump with a front inducer

At three flow conditions (0.8Qd, 1.0Qd, and 1.2Qd), the centrifugal pump cavity with front inducer was expanded at 0°, 90°, 180°, and 270°, and a flow path analysis of the axial cross section at the four angles was performed. This revealed that the circumferential and radial velocities of the liquid in the pump cavity along the same angle at different radii follow an axial and radial variation law to different degrees. The pump cavity center axial liquid velocity component along the radial distribution at different angles was analyzed, and liquid pressure in the pump cavity along the radial distribution was numerically analyzed from different points of view. The mean pump cavity pressure was plotted along the radial distribution curve, and a detailed numerical calculation of the axial force of the centrifugal pump and pump cavity was developed. The influence of flow conditions on the liquid flow mechanism and axial force characteristics in the pump cavity was thoroughly discussed. The results showed that liquid flow in the centrifugal pump cavity with the front inducer is mainly restricted by the main flow of the volute. The liquid eddy current in the pump cavity is mainly concentrated near the volute and the hub at 90° and 180° angles, and the higher the flow rate, the larger is the area of the side vortex of the impeller-cover plate, and the smaller is the area of the side vortex of the pump-cover plate. When the flow rate increases, the flow direction of the eddy current at the same angle in the pump cavity remains unchanged, but when the flow rate becomes too high, the flow direction of the eddy current at the same angle in the pump cavity changes. When the range of circumferential and radial partial velocities decreases, the rotational angular velocity increases, and the pressure decreases. At low flow rate, the larger the area of the volute corresponding to the pump cavity, the higher the speed becomes. The axial force in the pump cavity is the most important factor determining the axial force of the centrifugal pump

Establishing reference intervals of coagulation indices based on the ACL Top 700 system for children in Southwestern Fujian, China

Abstract(#br)Background(#br)Till date, China has not issued industry standards for reference intervals (RIs) of pediatric blood coagulation indices. Here, we evaluated changes in the coagulation indices in the venous blood of healthy children aged 29 days to 12 years derived using the ACL Top 700 system and established appropriate RIs.(#br)Methods(#br)We analyzed venous blood from 1770 healthy children for five coagulation indices. RIs were established according to the Clinical and Laboratory Standards Institute C28-A3c guideline.(#br)Results(#br)The coagulation indices were grouped by age. For prothrombin time (PT) and international normalization ratio (INR), the RIs of infants and toddlers were identical; preschool children had the same RI as school-age children. Pediatric RIs for PT and INR were slightly lower than those for adults. The RIs of activated partial thromboplastin time (APTT), thrombin time (TT), and fibrinogen (FIB) in childhood were divided into two groups by age (1 month to 1 year and 1–12 years). The RI of APTT in infants was the widest; the overall level of FIB in infants was the lowest; children’s APTT and FIB RIs were lower than those of adults. The pattern of TT values and RI trends in childhood were similar to those of APTT.(#br)Conclusions(#br)There were minor changes in the RIs of coagulation indices for children. The RIs of PT, INR, APTT, TT, and FIB must be grouped by age. The RIs of coagulation indices for children were different from those for adults; therefore, establishing separate RIs for children is necessary

Establishing reference intervals of coagulation indices based on the ACL Top 700 system for children in Southwestern Fujian, China.

BACKGROUND(#br)Till date, China has not issued industry standards for reference intervals (RIs) of pediatric blood coagulation indices. Here, we evaluated changes in the coagulation indices in the venous blood of healthy children aged 29 days to 12 years derived using the ACL Top 700 system and established appropriate RIs.(#br)METHODS(#br)We analyzed venous blood from 1770 healthy children for five coagulation indices. RIs were established according to the Clinical and Laboratory Standards Institute C28-A3c guideline.(#br)RESULTS(#br)The coagulation indices were grouped by age. For prothrombin time (PT) and international normalization ratio (INR), the RIs of infants and toddlers were identical; preschool children had the same RI as school-age children. Pediatric RIs for PT and INR were slightly lower than those for adults. The RIs of activated partial thromboplastin time (APTT), thrombin time (TT), and fibrinogen (FIB) in childhood were divided into two groups by age (1 month to 1 year and 1-12 years). The RI of APTT in infants was the widest; the overall level of FIB in infants was the lowest; children’s APTT and FIB RIs were lower than those of adults. The pattern of TT values and RI trends in childhood were similar to those of APTT.(#br)CONCLUSIONS(#br)There were minor changes in the RIs of coagulation indices for children. The RIs of PT, INR, APTT, TT, and FIB must be grouped by age. The RIs of coagulation indices for children were different from those for adults; therefore, establishing separate RIs for children is necessary

An Asymmetric Hysteresis Model and Parameter Identification Method for Piezoelectric Actuator

Hysteresis behaviour degrades the positioning accuracy of PZT actuator for ultrahigh-precision positioning applications. In this paper, a corrected hysteresis model based on Bouc-Wen model for modelling the asymmetric hysteresis behaviour of PZT actuator is established by introducing an input bias φ and an asymmetric factor ΔΦ into the standard Bouc-Wen hysteresis model. A modified particle swarm optimization (MPSO) algorithm is established and realized to identify and optimize the model parameters. Feasibility and effectiveness of MPSO are proved by experiment and numerical simulation. The research results show that the corrected hysteresis model can represent the asymmetric hysteresis behaviour of the PZT actuator more accurately than the noncorrected hysteresis model based on the Bouc-Wen model. The MPSO parameter identification method can effectively identify the parameters of the corrected and noncorrected hysteresis models. Some cases demonstrate the corrected hysteresis model and the MPSO parameter identification method can be used to model smart materials and structure systems with the asymmetric hysteresis behaviour

Replication and Transmission of H9N2 Influenza Viruses in Ferrets: Evaluation of Pandemic Potential

H9N2 avian influenza A viruses are endemic in poultry of many Eurasian countries and have caused repeated human infections in Asia since 1998. To evaluate the potential threat of H9N2 viruses to humans, we investigated the replication and transmission efficiency of H9N2 viruses in the ferret model. Five wild-type (WT) H9N2 viruses, isolated from different avian species from 1988 through 2003, were tested in vivo and found to replicate in ferrets. However these viruses achieved mild peak viral titers in nasal washes when compared to those observed with a human H3N2 virus. Two of these H9N2 viruses transmitted to direct contact ferrets, however no aerosol transmission was detected in the virus displaying the most efficient direct contact transmission. A leucine (Leu) residue at amino acid position 226 in the hemagglutinin (HA) receptor-binding site (RBS), responsible for human virus-like receptor specificity, was found to be important for the transmission of the H9N2 viruses in ferrets. In addition, an H9N2 avian-human reassortant virus, which contains the surface glycoprotein genes from an H9N2 virus and the six internal genes of a human H3N2 virus, showed enhanced replication and efficient transmission to direct contacts. Although no aerosol transmission was observed, the virus replicated in multiple respiratory tissues and induced clinical signs similar to those observed with the parental human H3N2 virus. Our results suggest that the establishment and prevalence of H9N2 viruses in poultry pose a significant threat for humans