Adjacent Spacing Research Articles

An Integrated Potato-Planting Machine with Full-Film Mulching and Ridged Row Soil Covering

This paper presents the design of an integrated potato-planting machine capable of full-film covering, creating micro-ditches on ridges, and covering seed rows with soil. The machine addresses the challenges of traditional methods, allowing for mechanized planting with complete film coverage and individual seed row soil covering. The key components of the prototype were analyzed and designed. This includes the seeding system, the pointed wing-shaped trencher for creating micro-ditches, and the straddling film-mulching device. Additionally, the operating mechanism of these core components was analyzed. Field trials demonstrated an 85% success rate for seed depth placement under the film. The machine also achieved a 90% qualified index for seed potato spacing, with a 6% repetitive seeding rate and a 3% missed seeding rate. Furthermore, the qualified rate for covered soil width on seed rows was 94%, and the qualified rate for covered soil thickness was 93%. The adjacent row spacing achieved an 88% success rate. The degree of mechanical damage to the exposed surface of the mulch film was minimal, at only 30.2 mm2/m2. These results meet all the national and industry standards. The successful field trials confirm the effectiveness of the machine in performing integrated fertilization, sowing, ridging, full-film covering, and seed row soil covering. Compared to traditional methods, this machine significantly reduces labor intensity for farmers and enhances the economic value of potato planting.

Geometrical design method of Walker constellation in non-terrestrial network

To meet the requirement of mega low earth orbit (LEO) constellation design in non-terrestrial network (NTN), a geometric configuration design method of Walker constellation applicable to arbitrary latitude range coverage multiple and satellite quantity scale is proposed. First, a Walker configuration representation based on the streets of coverage (SoC) characteristic parameters is proposed. Then, satellite quantity required for coverage and the SoC parameters are estimated by calculating the width and adjacent spacing of SoC, which can improve the enumeration efficiency. Finally, by adjusting the phase and quantity of the satellite on the SoC, the constellation configuration with optimal comprehensive performances is selected from multiple groups of results. To demonstrate the effectiveness of the proposed design method, the performance comparisons among the existing mega LEO constellation systems are conducted. Compared with the existing configurations, the configuration calculated by the proposed method can efficiently reduce the satellite quantity required for coverage by about 20%, and can also satisfy the comprehensive demands including coverage performance, inter-satellite link, configuration redundancy and collision avoidance by reasonably selecting configuration parameters.

An enhanced expanding and shift sparse array based on the coprime array and nested array

AbstractIn recent years, sparse arrays based on the fourth‐order difference coarray (FODCA) have received increased research attention due to their small number of array elements and large consecutive virtual arrays. The expanding and shift structure based on the nested array (NA) and coprime array (CPA) (EAS‐NA‐CPA) is the representative one. The EAS‐NA‐CPA comprises two sparse subarrays, wherein the NA is expanded and shifted according to the second‐order difference coarray of the CPA. Although the number of consecutive elements is large, there are many redundant elements in the FODCA of the EAS‐NA‐CPA. To decrease the number of redundant elements and increase the number of consecutive elements in the FODCA, the authors proposed the enhanced EAS‐NA‐CPA (EEAS‐NA‐CPA). Compared with the original EAS‐NA‐CPA, the EEAS‐NA‐CPA increases the adjacent physical sensor spacing further by using more fourth‐order cross‐correlation coarrays in the FODCA, which are not considered in the original EAS‐NA‐CPA. By performing a theoretical analysis of the FODCA provided by the proposed EEAS‐NA‐CPA, the sensor spacing in the expanded NA was further increased to obtain a larger number of consecutive elements compared with the original EAS‐NA‐CPA. Furthermore, the relationship between the number of physical sensors and corresponding number of consecutive elements provided by the FODCA was explicitly expressed. Experimental simulations were conducted to verify the effectiveness of the proposed sparse array for the fourth‐order cumulant‐based direction of arrival estimation.

Study on the Driver Visual Workload of Bridge-Tunnel Groups on Mountainous Expressways

Mountainous expressways with bridge-tunnel groups are characterized by complex environments and high driving risks, making them crucial sections for highway safety. This study applied eye-tracking techniques to evaluate driving safety and comfort in bridge-tunnel groups. Drivers’ pupil diameter and fixation point distribution were measured in real vehicle tests. The influence of tunnel length, adjacent tunnel spacing, and natural lighting on drivers’ pupil diameters were compared and analyzed. The maximum transient velocity of pupil area was introduced to describe the drivers’ visual load and driving comfort. The results indicate that the driving workload reaches its maximum in the first tunnel in bridge-tunnel groups and is positively correlated with the tunnel length in other sections. Excessive or insufficient distance between adjacent tunnels is detrimental to driving comfort. The driving workload is higher at night compared to during the day. Moreover, the greater tunnel length in bridge-tunnel groups and the larger number of tunnels, suggest a higher driving workload for drivers. Above all, strengthening the design and management of bridge-tunnel groups in mountainous expressways is necessary.

Optimization of Process Parameters and Mechanical Properties of 316L Stainless Steel Block via Arc Additive Manufacturing

_ A study was conducted on the influence of current, spacing, current mode, and arc length on the formation of adjacent weld overlays in the 316L stainless steel block melting process using an extremely inert gas-shielded arc additive manufacturing method. The main defect observed during the formation of adjacent weld overlays was the incomplete fusion at the bottom. When using direct current, low current and short arc length could ensure the flatness of the overlay surface, and the fusion at the bottom of the adjacent weld overlays was improved, but the problem of incomplete fusion remained unresolved. When using pulse current, low current, short arc length, and continuous welding method could solve the problem of bottom fusion of adjacent weld overlays. Due to the thermal influence during the accumulation of adjacent weld overlays, the microstructure inside the weld overlay was uneven, and the crystallographic texture in the entire weld overlay was not formed. With a pulse current of 80 A, adjacent weld overlay spacing of 4.5 mm, travel speed of 200 mm/min, dry elongation of 10 mm, and arc length of 2 mm, the tensile strengths of the block in the X, Y, and Z directions were 568.5, 570.3, and 550.7 MPa, respectively, and the fracture elongations were 46%, 48%, and 43.3%, respectively. The strength and plasticity in the Z-direction were lower than those in the X and Y directions. Keywords 316L stainless steel; arc additive manufacturing; incomplete fusion; pulse current

Mechanical behavior of monolayer MoS2 films with arrayed dislocation defects

Compared with single and randomly distributed defects, arrayed defects exist widely in the film structure and can be designed artificially to achieve various specific functions. However, the mechanical behavior of transition metal dihalides with dislocation array defects is unclear; this limits their application in new flexible nanodevices. In this study, the strength and fracture properties of monolayer MoS2 films containing 5|7 (S5|7 and Mo5|7) dislocation defects under uniaxial tension were studied by molecular dynamics simulation. The results show that the number of defects, adjacent spacing, and alignment angle affect the critical strain and tensile strength of the monolayer MoS2 films. These results provide a basis for further understanding the mechanical behavior of monolayer MoS2 thin films and provide a theoretical reference for the application of nano-electronic devices based on MoS2.

Dredging the Charge-Carrier Transfer Pathway for Efficient Low-Dimensional Ruddlesden-Popper Perovskite Solar Cells.

Low-dimensional Ruddlesden-Popper (LDRP) perovskites still suffer from inferior carrier transport properties. Here, we demonstrate that efficient exciton dissociation and charge transfer can be achieved in LDRP perovskite by introducing γ-aminobutyric acid (GABA) as a spacer. The hydrogen bonding links adjacent spacing sheets in (GABA)2 MA3 Pb4 I13 (MA=CH3 NH3 + ), leading to the charges localized in the van der Waals gap, thereby constructing "charged-bridge" for charge transfer through the spacing region. Additionally, the polarized GABA weakens dielectric confinement, decreasing the (GABA)2 MA3 Pb4 I13 exciton binding energy as low as ≈73 meV. Benefiting from these merits, the resultant GABA-based solar cell yields a champion power conversion efficiency (PCE) of 18.73 % with enhanced carrier transport properties. Furthermore, the unencapsulated device maintains 92.8 % of its initial PCE under continuous illumination after 1000 h and only lost 3 % of its initial PCE under 65 °C for 500 h.

Dredging the Charge‐Carrier Transfer Pathway for Efficient Low‐Dimensional Ruddlesden‐Popper Perovskite Solar Cells

AbstractLow‐dimensional Ruddlesden‐Popper (LDRP) perovskites still suffer from inferior carrier transport properties. Here, we demonstrate that efficient exciton dissociation and charge transfer can be achieved in LDRP perovskite by introducing γ‐aminobutyric acid (GABA) as a spacer. The hydrogen bonding links adjacent spacing sheets in (GABA)2MA3Pb4I13 (MA=CH3NH3+), leading to the charges localized in the van der Waals gap, thereby constructing “charged‐bridge” for charge transfer through the spacing region. Additionally, the polarized GABA weakens dielectric confinement, decreasing the (GABA)2MA3Pb4I13 exciton binding energy as low as ≈73 meV. Benefiting from these merits, the resultant GABA‐based solar cell yields a champion power conversion efficiency (PCE) of 18.73 % with enhanced carrier transport properties. Furthermore, the unencapsulated device maintains 92.8 % of its initial PCE under continuous illumination after 1000 h and only lost 3 % of its initial PCE under 65 °C for 500 h.

Mechanism of Ti-rich grain boundary phase formation and coercivity reinforcement in Sm(Fe0.8Co0.2)11TiBx melt-spun ribbons

The effects of boron doping on the microstructure and magnetic properties of Sm(Fe0.8Co0.2)11TiBx melt-spun ribbons were investigated. At a quenching speed of 25 m/s, the Ti-rich grain boundary (GB) phase and more percent of SmFe12 phase was formed in the sample with x = 0.25, which increase the coercivity from 3 kOe to 6 kOe and remanence from 61 emu/g to 75 emu/g. The Ti-rich grain boundary phase show TiFe2-type structure, in which the (02–1) plane spacing of the grain boundary phase is half that of the adjacent (020) plane spacing of ThMn12 phase. Electron holographic analysis showed that the Ti-rich GB phase can reduce the magnetization coupling between the SmFe12 main phase grains. This served as a guide for the further fabrication of the GB phase in SmFe12-based permanent magnetic materials with high magnetic properties.

Crosstalk in CMOS Terahertz Detector Array With On-Chip SPR Antenna

Although surface plasmon resonance (SPR) antennas have been integrated into CMOS THz detectors as an alternative to the traditional radio-wave antenna, spatial crosstalk of SPR antenna in detector arrays remains an issue and there is little study in this field. In this paper, a CMOS THz detector array at 0.65 THz with on-chip SPR antennas is designed in standard CMOS technology and the pixel crosstalk related to the SPR antenna parameters are investigated. Simulation results show that the adjacent SPR antenna spacing significantly affect the antenna crosstalk due to the surface wave propagation. To suppress the pixel crosstalk, the adjacent SPR antenna spacing is designed as 1.65 times larger than half of the antenna size. Under the condition, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S₁₂</i> parameter between the adjacent antennas is reduced to -15 dB. High antenna isolation can be further available by the increase of the isolation layer thickness of the pixel up to 1 μm. Based on the simulation results, a 1×16 THz detector array at 0.65THz was fabricated. The experimental results show that the pixels in the array achieve uniform <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">NEP</i> , with an average value of about 32.6 pW/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sup> and a standard deviation coefficient of about 9.6%. The results can be further optimized to meet various crosstalk requirements for CMOS THz detectors.

Array of photonic hooks generated by multi-dielectric structure

Generation of array of photonic hooks (PHs) by a multi–dielectric structure that consists of periodically arrayed scatterer units has been systematically studied. The study focuses on the effects of geometric and optical parameters of the multi–dielectric structure on the characteristics of generated PHs, especially their bending angles. These geometric and optical parameters include size, shape, refractive index and number of scatterer units, and their adjacent spacing. The results show that the spacing, size and refractive index play a predominant role in tailoring the performance of the PHs array, and the spacing affects mainly the characteristics of a pair of symmetrical PHs while the size and refractive index differences between scatterer units affect mainly those of asymmetrical PHs as a result of the introduction of optical inhomogeneity. In the aspect of scatterer shape, for a multi–dielectric structure that consists of some cylinders, as the light wave is incident parallel (perpendicular) to the cylinder axis, its scattering characteristics are similar to those of the multi–dielectric structure that consists of some cuboids (spheres). In particular, for a structure consisted of cylinders or cuboids with long length in the z direction, an intensive photonic nanojet is additionally generated and located between the paired PHs provided that the wave is incident perpendicular to the cylinder axis or the longest side of cuboid. In the aspect of scatterer unit number, the multi–dielectric structures of odd and even scatterer units generate PHs with different characteristics. The paired PHs generated by multi–dielectric structure with equal spacings always bend outward. However, the paired PHs may bend inward provided that the multi–dielectric structure is designed properly. We have also studied the features of 2D PHs array. The results show that the 2D PHs array displays similar features to the 1D case. The application potential of both 1D and 2D PHs arrays is evaluated.

Far-Field 3-D Localization of Radioactive Hotspots via Four-Eyes Stereo Gamma Camera

In the fields of radiation environment monitoring and unknown radioactive materials search, locating the far-field gamma-ray sources with high accurate coordinates is an important and necessary capability for a gamma imager. However, traditional coded gamma-ray imaging systems only provide 2-D radiation images without distance information. In this work, a four-eyes stereo gamma camera is proposed, which consists of four independent coded aperture detectors with an adjacent spacing of 286 mm. Each detector is comprised of pixelated scintillators with a pixel array of 44 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times44$ </tex-math></inline-formula> , forming a global detection area of 140 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times140$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The ranging capability is related to the resolution and the adjacent spacing of the detectors. With the setup of the above device, the traditional binocular-based ranging method has a short measurement range and a large measurement deviation. Here, a min-area distance measurement algorithm based on a four-eyes stereo gamma camera is proposed, combined with “manual” fine sampling and Gaussian fitting method to successfully achieve the high-precision localization of the far-field source. The simulation results show that compared with the traditional binocular-based ranging method, the min-area method based on a four-eyes stereo camera lengthens the range from 20 m to more than 50 m and improves the ranging accuracy within 20 m by more than six times. The accuracy of 20 and 50 m is less than 1.4 m (7.13%) and 10.5 m (21%), respectively. The reliability of the simulation results has been verified by experiments. Furthermore, the ranging capability of this algorithm for multipoint sources in the far field has been verified.

Research on overvoltage protection of adjacent distribution network by lightning striking plant grounding network dissipation

In order to study the lightning strike plant grounding network scattered flow on the adjacent distribution network overvoltage protection, the establishment of the installation of extended lead, the laying of vertical grounding body and the installation of isolation belt three plant and adjacent distribution line overvoltage protection model, analysis of the 10 kV distribution line and the adjacent plant grounding network spacing, soil resistivity and lightning current amplitude on the adjacent plant line lightning overvoltage impact, and compared the diversion method and insulation spacing method protection effect. The research results show that: the installation of extended lead, the laying of vertical grounding body and the installation of isolation belt can effectively reduce the distribution line overvoltage, the installation of extended lead voltage reduction effect is the best, voltage reduction efficiency is stable in more than 20%; distribution line and the adjacent plant grounding network spacing and soil resistivity has a great impact on the voltage reduction efficiency after protection, but the lightning current amplitude has little impact on the voltage reduction efficiency after protection. The research results can provide reference for the overvoltage protection of distribution lines when the actual lightning strikes the plant.

(Digital Presentation) Fabricating SERS-Active Nanofibers Covered with Au Nanoparticles for SERS Optophysiology

Nanofibers as biosensors have attracted great attention due to its facile removal from the biosystem after a period of intra- or extracellular measurements and site-specific measurement among others. The application of nanofibers covered with Au nanoparticles as SERS sensor circumvents the aggregation and accumulation of Au nanoparticles in vitro or in vivo, in addition to the greater Raman enhancement of signal than on planar surface. We report here on a strategy using block copolymer brush-layer templating and ligand exchange for fabricating highly reproducible and stable SERS-active nanofibers with tip diameters down to 60 nm and covered with well-dispersed and uniformly distributed branched AuNPs, which have intrinsic hotspots favoring inherently high plasmonic sensitivity. In addition, AuNPs with tunable morphology and adjacent spacing on the nanofibers can be adjusted using an in situ growth technique, thereby enhanced SERS sensitivity was obtained due to the asymmetric structure and coupling between the adjacent AuNPs. Tunable AuNP morphologies and hence the optical characteristics of the AuNPs on the nanofibers can be easily controlled by choice of experimental parameters, particularly the growth time. Besides, finite difference time domain (FDTD) simulations were performed to gain more insight into the electric-field enhancement of AuNPs on the high-curvature substrates. Furthermore, SERS application of these nanosensors in pH sensing and Hg2+ detection is demonstrated here, offering appealing and promising candidates for real time monitoring of extra/intra-cellular species in vitro or in vivo. In addition to SERS sensing, these highly uniform nanosensors have other far-reaching implications, including medical diagnostics, therapeutics and so on.

The roles of functional groups of antifreeze protein in inhibition of hydrate growth

The search for green and efficient inhibitors to solve the hydrate blockage problem is a widespread concern in natural gas hydrate exploitation and oil/gas transportation. Tenebrio molitor antifreeze protein (TmAFP) as a biodegradable substance with a high value of thermal hysteresis activity has an excellent inhibition effect on ice growth. Considering that gas hydrates are ice-like solids, we performed molecular dynamics simulations on TmAFP to study its inhibition behavior on methane hydrate growth. Our results show that TmAFP adsorbs on hydrate growth surface by providing several functional groups as “central gas” to be trapped in half hydrate cages where the methyl groups of threonine residues have the highest chance. Moreover, the amide groups of amino acids can also be engaged in half cages. Since these amino acids are uncharged and polar, we infer that they interact with the half-cage with mainly hydrogen bonding. Surprisingly, all adsorption sites were non-ice binding sites and TmAFP can disrupt surrounding water molecules before adsorption, unlike the behavior of previously well-studied fish antifreeze proteins. However, functional groups of the backbone of the ice-binding surface on the β-sheet do not act as the adsorption sites. The reason is that the backbone is not easily deformable and the amino acid group spacing in this part does not match the adjacent hydrate cage spacing. This implies that the structure of the antifreeze protein has a crucial role in hydrate growth inhibition. When seeking efficient antifreeze proteins for hydrate growth inhibition, functional groups as well as their relative positions should be simultaneously considered. These studies guide the development of green and efficient kinetic hydrate growth inhibitors.

Effect of Mg(II), Mn(II), and Fe(II) doping on the mechanical properties and electronic structure of calcite

Calcite is one of the most important rock-forming minerals in the earth's crust, it is a very common mineral in nature and is widely used. Metal ions, such as Mg(II), Mn(II) and Fe(II), are often introduced into calcite as defects, which have a great influence on the crystal structure, mechanical properties and electronic structure of calcite. In order to understand the mechanism of the Mg(II), Mn(II), and Fe(II) doping of calcite, first-principles calculations are used to comprehensively study the various properties of calcite doped with different ions from an atomic-scale perspective. The calculation results show that the bonding characteristics of adjacent carbonate ions and layer spacing change after Mg-, Mn-, and Fe-doping, and the influence of Fe(II) on the calcite properties is the greatest, followed by those of Mn(II) and Mg(II). The influence of Fe(II) on the calcite properties is related to the ion radius and distribution of extra nuclear electrons. The elastic modulus of doped calcite decreases substantially, but the hardness of the material increases. The distribution of the density of states, energy band structure, and electrical conductivity of calcite doped with different ions also change significantly, which result in a variation in the electrical properties of calcite.

PO-695-03 A NOVEL FOCAL PULSED FIELD ABLATION CATHETER FOR CAVO-TRICUSPID ISTHMUS ABLATION: FIRST-IN-HUMAN EXPERIENCE

The cavotricuspid isthmus (CTI) is a common adjunct target for ablation during pulmonary vein isolation (PVI) procedures. Current modalities for CTI ablation require adjacent spacing of thermal lesions, are contact dependent, and rarely, can injure the right coronary artery. Further, the CTI can have a complex topography that challenges catheter positioning. Pulsed field ablation (PFA) may facilitate CTI ablation due to its speed, reduced contact-dependence, and preferential myocardial injury.

再生稻机收碾压稻茬扶正机设计与试验

For rice ratooning, the lateral bud germination of the rice stubble after the first harvesting can be used to continue the next growing season, but the first harvesting machinery will crush and damage the rice stubble, resulting in the reduction of yield in the ratooning season. Lifting the rolled stubble can reduce this loss, and thus a double-chain finger grain lifter was designed in this study. Then, a kinematic model and motion trajectory curve of the grain lifter was established. The influence law of the chain speed, chain spacing and the number of fingers of the rear lifting chain was determined. Furthermore, taking into account the success rate and the rate of secondary damage of the lifting, a full-factor bench test was performed. The best operating characteristics of the grain lifter are: chain speed of 345 r/min, adjacent chain spacing of 300 mm, and the number of gears and fingers on the rear lifting chain of 3. The success rate and the secondary damage rate of the lifting is 90.05% and 1.72%, respectively. A field verification test was conducted, with an average success rate of 55%. The results of this study can provide valuable reference for the lifting technology of rolled rice stubble and promote the whole mechanized production of ratoon rice.

Wind Forces and Flow Patterns of Three Tandem Prisms with a Small Height–Width Ratio

Wind tunnel tests and large eddy simulations were conducted to investigate the dependency of wind forces and flow patterns on the spacing (S) for three tandem prisms with a small height–width ratio H/W = 0.4. At the spacing ratio S/W = 0.7, mean and root-mean-square drag of downstream prisms have large local peaks, and their magnitudes are larger than those at adjacent spacing ratios; these should be noted to ensure the safety and economy of the wind-resistant design of prism-like low-rise buildings. These phenomena are different from that of a small group of tandem prisms with a large H/W and a large group of tandem prisms with a small H/W. At S/W = 0.7, tap pressure time histories of downstream prisms are non-stationary with abrupt changes, but wind force time histories of downstream prisms are stationary, unlike a small group of tandem prisms with a large H/W, where both tap pressure and win d force time histories are non-stationary. Above phenomena at S/W = 0.7 are attributed to a special asymmetric time-averaged wake regime, which has two modes with symmetric wake flow directions and they irregularly switch. The duration of each mode is ruleless. This special wake regime was not observed in previous studies on tandem prisms.

Optimization Design on a High-performance Magnetic Shielding Barrel for Atomic Magnetometer Measurement Application

The ultra-high-precision measurement of the atomic magnetometer is largely restricted by the size of its working magnetic field. In order to reduce the residual magnetic field as much as possible, this article carried out the research on the methods to improve the shielding performance. Firstly, the axial shielding factor that limits the shielding performance of the magnetic shielding barrel was derived with various parameters including the radius, length, thickness, number of layers, distance between adjacent layers, etc. of the magnetic shielding barrel. Secondly, simulation was carried out to verify the correctness of the formula. Simulation shows that the shielding performance of the magnetic shielding barrel decreases with the size of magnetic shielding barrel increase. Besides, with the increase of the distance between two adjacent spacing layers, the shielding performance first increases rapidly and then gradually decreases, indicating that the optimal distance between adjacent layers is 9mm. Especially, the performance of the magnetic shielding barrel improves significantly as the layer thickness and number of layers increase. Experimental results show that the internal remanence of the three-layer magnetic shielding barrel is less than 1nT, and the available axial length of homogeneity range is greater than 200mm.