Pole Array Research Articles

One-Shot Remote Integration of Macromolecular Synaptic Elements on a Chip for Ultrathin Flexible Neural Network System.

The field of biomimetic electronics that mimicsynapticfunctionshas expanded significantly to overcome the limitationsofthevon Neumann bottleneck. However, the scaling down of the technology has led to an increasingly intricate manufacturing process. To address the issue, this work presents a one-shot integrable electropolymerization (OSIEP) method with remote controllability for the deposition of synaptic elements on a chip by exploiting bipolar electrochemistry. Condensing synthesis, deposition, and patterning into a single fabrication step is achieved by combining alternating-current voltage superimposed on direct-current voltage-bipolar electropolymerization and a specially designed dual source/drain bipolar electrodes. As a result, uniform 6 × 5 arrays of poly(3,4-ethylenedioxythiophene) channels are successfullyfabricatedon flexible ultrathin parylene substrates in one-shot process. The channels exhibited highly uniform characteristics and are directly used as electrochemical synaptic transistor with synaptic plasticity over 100 s. The synaptic transistors have demonstrated promising performance in an artificial neural network (NN) simulation, achieving a high recognition accuracy of 95.20%. Additionally, the array of synaptic transistor is easily reconfigured to a multi-gate synaptic circuit to implement the principles of operant conditioning. These results provide a compelling fabrication strategy for realizing cost-effective and disposable NN systems with high integration density.

Wolverine density, survival, and population trends in the Canadian boreal forest

AbstractThere is limited information available on wolverine (Gulo gulo) population density and trends in the boreal forest of North America. We estimated wolverine density using spatial capture‐recapture methods across 2 boreal forest study areas in Red Lake, Ontario (26,568 km2) and Rainbow Lake, Alberta (19,084 km2), Canada. We also used radio‐telemetry data to estimate annual survival of adult and sub‐adult wolverines and evaluated population trends with a stage‐based matrix model. We used an array of run poles and live traps to detect wolverines. In Red Lake over 3 winter field seasons (2019–2022), we detected 56 individual wolverines (17 females, 32 males, and 7 unknown sex), and in Rainbow Lake over 2 field seasons (2014–2016), we detected 48 individuals (19 females, 18 males, and 11 of unknown sex). Average densities in Red Lake and Rainbow Lake were 3.64 and 6.74 wolverines/1,000 km2, respectively. Adults and sub‐adults occurred at equal abundance. Spring snow cover, roads, and industrial developments were not associated with spatial patterns of wolverine density. Most deaths occurred near roads; wolverines were killed in fur traps set along roads, by wolves using roads to travel, and by vehicles. The largest source of death was from incidental (n = 6 in Red Lake) or licensed fur trapping (n = 8 in Rainbow Lake) and we report 8 injuries from fur trapping sets. Red Lake survival estimates for adults (0.87) and sub‐adults (0.86) contributed to a stable population trend. Rainbow Lake survival estimates for adults (0.66) and sub‐adults (0.50) contributed to a declining population trend based on a relatively low sample of radio‐days. Red Lake and Rainbow Lake combined survival estimates for adults (0.77) and sub‐adults (0.73) also contributed to a declining population trend. Our survival and population modeling suggests that human‐caused mortality is a significant risk to these populations. Our results can be applied to wolverine status assessments and used as benchmarks for future monitoring. Wolverine population stability or growth might be achieved by reducing incidental trapping deaths or injury and hindering human access to wolverine habitats through decommissioning or limiting development of industrial roads or other anthropogenic linear features.

Thermomagnetic convection induced in a temperature stratified state by a Halbach magnetic field

Convection induced by the permanent magnets of the linear Halbach array is numerically investigated and validated experimentally. The working fluid is a paramagnetic fluid that is weakly attracted to the magnet with temperature dependency. The fluid is filled in a rectangular enclosure and heated from the top and cooled from the bottom. The external magnetic field is applied from the top wall. Two-dimensional computations show that the Halbach magnet array can induce a strong thermomagnetic force widely in the fluid layer compared with the conventional alternate magnetic pole array. The upward flow is induced below the edges of the center magnet and then separated left and right along the top heated wall. The local Nusselt number shows a higher value and wider area than those by the conventional pole array. An experiment using the Halbach array kit is conducted and the obtained local Nusselt number profile agrees well with the computational data both qualitatively and quantitatively.

磁気式アブソリュートエンコーダの高精度化

The purpose of this study is to develop an absolute track recording method to develop a higher accuracy magnetic absolute encoder. Shortening the magnetic pole distance is effective to achieve higher accuracy, but the absolute position misdetection due to attenuation and interference of the magnetic signal on the absolute track decrease the accuracy. Therefore, a magnetic pole array and its decoding method are developed to solve the problems of magnetic signal attenuation and interference by increasing the magnetic pole spacing without allowing three or more identical magnetic poles in succession. When the magnetic pole distance is shortened, the magnetic signal of the absolute track of the developed method detects the absolute position with a larger sensor gap than the existing method. At the magnetic pole distance realized by the developed method, interpolation errors are reduced, confirming the high accuracy of the magnetic absolute encoder.

Dielectric properties of SrTiO3/LaNiO3 composite structure prepared by “sol-gel” method

In this work, Pt/SrTiO3(STO)/LaNiO3(LNO) and Pt/STO/Pt structures were fabricated on Si substrates using sol–gel method. Dielectric tunability characteristics of these two structures are investigated over temperature range of 300–80 K. As temperature decreases, relative dielectric constant and tunability of STO films in both structures increase linearly, while loss tangent (tanẟ) decreases. STO prepared on LNO exhibits better crystallinity and dielectric tunability than that prepared on Pt. Furthermore, LNO top pole array with 0.2 mm diameter was prepared on STO/LNO using photosensitive sol–gel method, resulting in LNO/STO/LNO structure with symmetric electrode. Dielectric tunability tests reveal that, compared with Pt/STO/LNO structure, LNO/STO/LNO structure exhibits similar tunability, lower tanẟ, higher figure-of-merit (FOM) values, and better tunability symmetry. Relative dielectric constant, tunability (350 kV/cm), and FOM are approximately 391, 60%, and 142.6 at 80 K, respectively. Further analysis shows that because of Schottky barrier at Pt/STO interface, the FOM and tunability symmetry of Pt/STO/LNO structure are worse than those of LNO/STO/LNO structure. These results demonstrate that LNO electrode performs better than conventional inert metal electrodes.

Bipolar Electrode Arrays for Chemical Imaging and Multiplexed Sensing.

Bipolar electrodes (BPEs) with arrays of cathodic and anodic poles were developed for use in closed bipolar systems. To increase the number of BPEs in the array, the anodic and cathodic poles were connected with each other using thin leads. A further increase in the number of BPEs was achieved by forming the cathodic and anodic poles of the BPEs and the leads in different layers. A device with 9 × 10 arrays of cathodes and anodes was thus realized. When using this device to sense hydrogen peroxide (H2O2), the sensitivity and linear range of calibration plots could be adjusted by changing the driving voltage and the area ratio between the cathodic and anodic poles. The devices were used to image H2O2 and obtain time-lapse images for the diffusion and dilution of H2O2. Furthermore, DNA detection was demonstrated using an electroactive intercalator. The sensitivity could be improved by making the anodic poles smaller with respect to the cathodic pole and concentrating the electrochemiluminescence (ECL) in a small area. The ECL intensity changed according to the target DNA concentration in the solution.

High-Resolution Separation of Nanoparticles Using a Negative Magnetophoretic Microfluidic System.

The separation and purification of a sample of interest is essential for subsequent detection and analysis procedures, but there is a lack of effective separation methods with which to purify nano-sized particles from the sample media. In this paper, a microfluidic system based on negative magnetophoresis is presented for the high-resolution separation of nanoparticles. The system includes on-chip magnetic pole arrays and permalloys that symmetrically distribute on both sides of the separation channel and four permanent magnets that provide strong magnetic fields. The microfluidic system can separate 200 nm particles with a high purity from the mixture (1000 nm and 200 nm particles) due to a magnetic field gradient as high as 10,000 T/m being generated inside the separation channel, which can provide a negative magnetophoretic force of up to 10 pN to the 1000 nm particle. The overall recovery rate of the particles reaches 99%, the recovery rate of 200 nm particles is 84.2%, and the purity reaches 98.2%. Compared with the existing negative magnetophoretic separation methods, our system not only exhibits high resolution on particle sizes (800 nm), but also improves the sample processing throughput, which reaches 2.5 μL/min. The microfluidic system is expected to provide a new solution for the high-purity separation of nanoparticles, as well as nanobiological samples.

Vector analysis of pole–pole array for determining the 3D boundary of object

ABSTRACTAn algorithm is proposed for the interpretation of resistivity data that allows the 3D parameters (the boundary in plan view and the depth range) of an anomalous resistivity object in a heterogeneous medium to be determined. The proposed method is based on a vector analysis of the apparent resistivity of soil obtained by a pole–pole survey within the measurement window. In the first stage of the algorithm, in each measurement window, the radius vector is calculated, and as a result, vector images of the main directions of change in the resistivity of the medium are constructed. This allows us to estimate the location of a local anomalous object and to correlate the resistivity of the object with that of the background medium. With a consistent variation in the effective depth of investigation, a set of vector images is formed that characterizes the apparent resistivity distribution in the soil layers. Mathematical analysis of the vector images by using the scalar product allows us to estimate the depth range of the anomalous object. The effectiveness of the proposed algorithm has been proven on synthetic models and in comprehensive investigations of archaeological sites. The proposed method does not allow the true resistivity of an anomalous object to be determined, which is a disadvantage. However, this simple algorithm for processing and analysing shallow electrical prospecting data can be directly used at the preliminary data processing stage during a field survey. First, a pole–pole array can be rapidly operated by a single person; second, the user does not need special knowledge in the field of electrical resistivity data processing. The estimated 3D boundaries of local objects will make it possible to determine the area of interest for further detailed surveying and to justify all the parameters of the measurement technique (distance between electrodes, depth range etc.).

Significant power enhancement method of magneto-piezoelectric energy harvester through directional optimization of magnetization for autonomous IIoT platform

Unlike previous piezoelectric energy harvesters that generate electrical energy from a magnetic field according to the magnetic strength or magnetostrictive material, the proposed method achieves significant power enhancement using directional optimization of magnetization. This method can serve as a ubiquitous autonomous energy source that converts a magnetic field into usable electrical energy in a wireless sensor network for an (Industrial) Internet of Things (IIoT). The key approach in the proposed model is to increase of the Lorentz force by vertically adjusting the magnetic flux direction of a power cable and the magnetic direction of a tip magnet. In the simulation, a 3592 times higher y-axis Lorentz force was obtained in the vertical pole array, which resulted in about a 1.6 times higher output voltage. Then, we experimentally compared the electrical output performance of six different types of pole array according to the size and direction of the tip magnet. In a one-tip magnet (10 × 10 × 10 mm3), the output power values were 2.34 mW (Vertical) and 1.23 mW (Horizontal) at 8 kΩ matching impedance. For two-tip magnets (20 × 10 × 10 mm3), the output power values of the harvester were 39.2 mW (Planar-Vertical), 18.4 mW (Orthogonal-Vertical), 8.64 mW (Planar-Horizontal), and 0.05 mW (Orthogonal-Horizontal) at 5 kΩ matching impedance. It was found that the power generation differed by 2.13 to 784 times. With this method of power enhancement using multi-disciplinary research, we successfully constructed autonomous IoT and IIoT sensor systems for smart homes, smart buildings and smart factories.

High Torque Density Torque Motor With Hybrid Magnetization Pole Arrays for Jet Pipe Servo Valve

Torque motor is one key component that directly influences the dynamic performance of jet pipe servo valve in aircraft. In this paper, a novel torque motor with hybrid-magnetization pole arrays is proposed. By changing the magnetization patterns of permanent magnets, the torque motor can significantly improve the output torque by range of 47–52% compared with traditional designs, while maintaining the system size and mass. The design concept and operating principle of the torque motor is presented. The magnetic field distribution is formulated analytically with equivalent magnetic circuit. Different from conventional study, the flux leakage of the permanent magnets and coils is included to improve the model precision. Subsequently, the output torque is derived mathematically from the airgap flux. Following that, the numerical calculation is conducted to validate the mathematical models of magnetic field and output torque. The design optimization is then carried out. One research prototype that can be mounted with either conventional magnet or the proposed hybrid array has been developed. The test rigs are constructed and experiments are conducted on the prototype. Both numerical computation and experimental results verify the significant improvement of torque generation of the proposed hybrid magnetization torque motor.

Electrode array and data density effects in 3D induced polarization tomography and applications for mineral exploration

Synthetic resistivity and chargeability models are employed to study the electrode array and data density effects in inversion resolution for 3D induced polarization tomography. Results from the inversion tests with different electrode arrays illustrate that the inversion resolution for electrical resistivity tomography (ERT) and induced polarization tomography (IPT) data with the dipole–dipole array perform better than the pole–pole array and pole–dipole array. In addition, the anomalous bodies with high impedance and high chargeability are hard to be reconstructed. In contrast, the ones with low resistivity and high chargeability can be well established. Results from the inversion tests with different data densities illustrate that the higher data density will yield better inversion resolution for the ERT and IPT data. We firstly employ the sensitivity analysis method and depth of investigation (DOI) index method to evaluate the inversion results. Then, we present the observation-to-parameter ratio (OPR) and model-drift ratio (MDR) for discussing and evaluating the quality of the inverted maps, and the result shows that the correlation can reach to the limit when the data density reaches a certain OPR value of 44. Results from the synthetic inversion tests generally provide reference and guidance for employing the measuring electrode with a suitable arrangement and reasonable number in the field ERT and IPT surveys. Lastly, IPT method with dipole–dipole array has been employed in the mining area with the better prospect of mineral exploration northwest of Gansu Province, China. Moreover, the inverted maps reveal three ore bodies with high resolution.

Evaluating Alternative Linear Vernier Hybrid Machine Topologies for Integration Into Wave Energy Converters

This paper discusses the development of linear vernier hybrid machines for use in wave energy converters. A number of topology options are explored to reduce magnet usage and improve performance for use as a linear generator. Consequent pole, V-shape, and Halbach arrays are designed for a target 25 kW specification. A discussion of overall cost of energy produced is used to justify using efficiency and power factor to asses fixed magnet mass topology variants. A power factor improvement from 0.38 to 0.72 is presented. Physical integration of the electrical machine into wave energy converters is considered including flooded experimental results of thermal behavior and polymer bearing wear.

Truncated Solutions of Painlevé Equation PV

We obtain convergent representations (as Borel summed transseries) for the five one-parameter families of truncated solutions of the fifth Painlev\'e equation with nonzero parameters, valid in half planes, for large independent variable. We also find the position of the first array of poles, bordering the region of analyticity. For a special value of this parameter they represent tri-truncated solutions, analytic in almost the full complex plane, for large independent variable. A brief historical note, and references on truncated solutions of the other Painlev\'e equations are also included.

On-surface synthesis of poly(p-phenylene ethynylene) molecular wires via in situ formation of carbon-carbon triple bond

The carbon–carbon triple bond (–C≡C–) is an elementary constituent for the construction of conjugated molecular wires and carbon allotropes such as carbyne and graphyne. Here we describe a general approach to in situ synthesize –C≡C– bond on Cu(111) surface via homo-coupling of the trichloromethyl groups, enabling the fabrication of individual and arrays of poly(p-phenylene ethynylene) molecular wires. Scanning tunneling spectroscopy reveals a delocalized electronic state extending along these molecular wires, whose structure is unraveled by atomically resolved images of scanning tunneling microscopy and noncontact atomic force microscopy. Combined with density functional theory calculations, we identify the intermediates formed in the sequential dechlorination process, including surface-bound benzyl, carbene, and carbyne radicals. Our method overcomes the limitation of previous on-surface syntheses of –C≡C– incorporated systems, which require the precursors containing alkyne group; it therefore allows for a more flexible design and fabrication of molecular architectures with tailored properties.

Chemotaxis arrays in Vibrio species and their intracellular positioning by the ParC/ParP system.

Most motile bacteria are able to bias their movement towards more favorable environments or to escape from obnoxious substances by a process called chemotaxis. Chemotaxis depends on a chemosensory system that is able to sense specific environmental signals and generate a behavioral response. Typically, the signal is transmitted to the bacterial flagellum, ultimately regulating the swimming behavior of individual cells. Chemotaxis is mediated by proteins that assemble into large, highly ordered arrays. It is imperative for successful chemotactic behavior and cellular competitiveness that chemosensory arrays form and localize properly within the cell. Here we review how chemotaxis arrays form and localize in Vibrio cholerae and Vibrio parahaemolyticus We focus on how the ParC/ParP-system mediates cell cycle-dependent polar localization of chemotaxis arrays and thus ensures proper cell pole development and array inheritance upon cell division.

Assessing the Performance of a Low-Cost Method for Video-Monitoring the Water Surface and Bed Level in the Swash Zone of Natural Beaches

A method to continuously measure bed and water levels along a cross-shore transect of vertical poles is evaluated. This remote sensing based method uses video imagery of swash flows propagating past an array of vertical poles buried on the beach face. Using datasets collected at two beaches in Chile, the method is compared against measurements obtained with conventional co-localized instruments: LiDAR and ultrasonic distance meters. The present video swash pole technique shows good skill in retrieving swash zone bed level and water levels, while providing the possibility to measure morphological variations at time scales varying from wave groups (tens of seconds) to hours. Discrepancies between video and ultrasonic distance meters are found when short time scales are used, for both depositional and erosion events, but longer duration trends are captured well. Water surface elevations at the wave-by-wave scale proved to be accurate for the backwash phase (root-mean-sqaure-error, RMSE down to 0.028 m, R 2 up to 0.89), when compared against LiDAR. However, discrepancies have been found during the uprush phase (RMSE up to 0.062 m, R 2 down to 0.71), when the influence of the pole on the swash flow generates an overestimation of the water surface. Overall, owing to its simplicity of deployment, low cost and reasonable accuracy, the technique is considered suitable for swash studies.

Needleless electrospray of magnetic film from magnetization-induced cone array

ABSTRACTElectrospray is a simple and versatile approach to deposit thin-films. Traditionally, electrospray is achieved through capillary nozzle electrode to create fluid jet. Here, we report a novel needleless electrospray approach to continuously deposit the magnetic film from the magnetization-induced self-assembling cone array of poly(vinyl pyrrolidone) (PVP)/Fe3O4 ferrofluid without any nozzle and feed unit. A spiral tower is used to pump the PVP/Fe3O4 ferrofluid and a 3D peak-cluster is self-assembled on the tip surface under an external magnetic field. The multiple and parallel jets can be continuously emitted from the cone array of 3D peak-cluster, and get deposited on the aluminum foil as a smooth magnetic film when a high-voltage electric field is further applied. This needleless electrospray approach is simple, and cost-effective with a high productivity. The prepared magnetic film mainly composed of Fe3O4 nanoparticles and PVP polymer exhibits superparamagnetic property and good magnetic field responsive property.

Augmentation of power conversion efficiency of amorphous silicon solar cell employing poly(methyl methacrylate-co-acrylic acid) nanospheres encapsulated with gold nanoparticles

An array of poly(methyl methacrylate-co-acrylic acid) nanospheres of various sizes (i.e., average size of 101 nm) with excellent thermal stability has been successfully synthesized via emulsion polymerization technique. The thermal properties of such materials in addition to the optical property of the metal nanoparticles have been carefully characterized. The integration of the nanospheres onto a photovoltaic cell has effectuated an increment of the power conversion efficiency from 2 to 3.14% (i.e., a relative enhancement of 57%). A further enhancement of the electrical characteristics has been observed if gold nanoparticles have been encapsulated by the polymeric nanospheres. The power conversion efficiency of the PV cell incorporated with gold nanoparticles of 3.75 × 10−3 wt% has attained 5.32% (i.e., a relative enhancement of 166%). This may be attributed to the localized surface plasmon effect as a strong absorption peak of the gold nanoparticles has been detected at the wavelength of 525 nm. A comparison of electrical characteristics conducted between nanospheres which have been encapsulated with silver and gold nanoparticles indicates the fact that both noble metals have yielded a momentous enhancement of the power conversion efficiency. Consequently, this novel technique utilizing nanospheres which have been encapsulated with noble metals (i.e., Ag and Au) is assuredly paving a way toward high-efficiency photovoltaic cell.

Out‐of‐plane effects in 2D borehole‐to‐surface resistivity tomography and applications in mineral exploration

ABSTRACTIn this paper, we discuss the effects of anomalous out‐of‐plane bodies in two‐dimensional (2D) borehole‐to‐surface electrical resistivity tomography with numerical resistivity modelling and synthetic inversion tests. The results of the two groups of synthetic resistivity model tests illustrate that anomalous bodies out of the plane of interest have an effect on two‐dimensional inversion and that the degree of influence of out‐of‐plane body on inverted images varies. The different influences are derived from two cases. One case is different resistivity models with the same electrode array, and the other case is the same resistivity model with different electrode arrays. Qualitative interpretation based on the inversion tests shows that we cannot find a reasonable electrode array to determine the best inverse solution and reveal the subsurface resistivity distribution for all types of geoelectrical models. Because of the three‐dimensional effect arising from neighbouring anomalous bodies, the qualitative interpretation of inverted images from the two‐dimensional inversion of electrical resistivity tomography data without prior information can be misleading. Two‐dimensional inversion with drilling data can decrease the three‐dimensional effect. We employed two‐ and three‐dimensional borehole‐to‐surface electrical resistivity tomography methods with a pole–pole array and a bipole–bipole array for mineral exploration at Abag Banner and Hexigten Banner in Inner Mongolia, China. Different inverse schemes were carried out for different cases. The subsurface resistivity distribution obtained from the two‐dimensional inversion of the field electrical resistivity tomography data with sufficient prior information, such as drilling data and other non‐electrical data, can better describe the actual geological situation. When there is not enough prior information to carry out constrained two‐dimensional inversion, the three‐dimensional electrical resistivity tomography survey is the better choice.

Fabrication and simulation of inverse poly(ferrocenylmethylvinylsilane)/silica opal structures and their optical properties

Photonic crystal structures were fabricated by the formation of periodic arrays of poly(ferrocenylsilane) (PFS) derivations and silica spheres. Here, we present the primary steps of a simulation-driven design of photonic crystal based on PFS as a potentially stimuli-responsive polymer, which can present predesigned color when subjected to the visible light. The poly(ferrocenylmethylvinylsilane) (PFMVS) was synthesized by photolytic anionic ring opening polymerization of methylvinylsila[1]ferrocenophane monomer under controlled condition and monodisperse silica spheres were synthesized by the Stober process. Bare silica opal was prepared by the convective self-assembly process of different sizes of silica spheres on glass substrate followed by infiltration of PFMVS to obtain PFMVS/silica opal and finally removal of the silica spheres by acid washing to attain the inverse PFMVS opal. The particle size of silica spheres along with the refractive indices contrast of different components forming photonic crystal played an important role in obtaining the maximum reflectance wavelength of the desired opal. Photonic crystal prepared by 210, 270, and 330 nm monodisperse silica spheres represents the blue, green, and red color, respectively. Simulation analyses of these opal structures were investigated by using the plane-wave expansion (PWE) method to assess the photonic crystal behavior versus the visible light. According to the simulation results, the photonic crystal structure was designed. The experimental reflectance outcomes of the three opal structures were in good agreement with the simulation analysis.