Adjacent Distance Research Articles

Synergistic Ru[sbnd]Co atomic pair with enhanced activity toward levulinic acid hydrogenation

Development of efficient metal-based catalysts is of great importance for levulinic acid (LA) hydrogenation to γ-valerolactone (GVL). The widely employed Ru-based catalysts are advantageous for H2 dissociation, however, the steric hindrance of large Ru particles hampers their coordination to CO moiety in LA, and thereby decreasing the activity. Herein, we report a Ru1Co1NC double single-atom catalyst (DSAC) with synergistic Ru and Co atomic pairs for LA hydrogenation into GVL. The Ru and Co doped zeolitic imidazole frameworks (RuCo-doped ZIF-8) precursor was rationally designed ((Ru + Co)/(Zn + Ru + Co) = 2 at.%), where the Zn node spatially isolates Ru and Co species, expanding the adjacent RuCo distance and facilitating the formation of the RuCo atomic pair upon pyrolysis, with each atom coordinated with three nitrogen atoms (N3Ru1Co1N3). The Ru1Co1NC catalyst exhibits outstanding catalytic activity, with a turnover frequency (TOF) of 1980 h−1, surpassing previously reported Ru-based catalysts. Experimental investigation and density functional theory (DFT) calculations reveal that the electron-rich Ru induced by less electronegative Co facilitates H2 dissociation, while atomic Ru in dual-atomic pairs promotes CO activation, Ru and Co atomic pairs synergistically enhancing LA conversion to GVL. This research will shed light on the precise control of active sites at atomic scale, and also provides a new concept for designing high-performance Ru-based catalysts towards LA hydrogenation to GVL.

Micromechanism of interparticle normal magnetic attraction effect in magnetorheological suspensions based on magnetic-dipole theory

In order to reveal adsorption-regulation micromechanism and debonding micromechanism between wall surface and magnetorheological (MR) wall-climbing robot legs, an interparticle normal magnetic attraction (NMA) mechanics model was constructed based upon the magnetic-dipole theory. According to analysis of NMA mechanics, it was confirmed that the interparticle NMA could be intensified with enhancing magnetic-particle diameter but was weakened with ratio of adjacent magnetic-particles distance to magnetic-particle radius. It means that the adhesive capacity between MR wall-climbing robot legs and wall surface could be strengthened by increasing magnetic-particle size and decreasing interparticle distance. Furthermore, it was found that the NMA of the first particle in the magnetic chain was positively related to magnetic-particles number until the magnetic-particles number reached a critical value. Consequently, the adsorption ability between MR wall-climbing robot legs and wall surface could be effectively controlled by changing magnetic-particles number. Besides, the strongest NMA appeared at the middle of the magnetic chain. However, the weakest NMA locates at both ends of the magnetic chain. Thus, it could be concluded that the end of the magnetic chain would be separated from wall surface rather than fracture occurred in the middle of the magnetic chain when the MR wall-climbing robot legs divorced from wall surface.

Tricolored Bat (Perimyotis subflavus) microsite use throughout hibernation

Abstract White-nose syndrome (WNS) has caused dramatic population declines in several bat species, including the Tricolored Bat (Perimyotis subflavus). Several studies have documented bats using colder roosting temperatures after infection; however, this strategy may have costs such as increased freezing risks or greater predation risks and it is unknown when during hibernation bats begin to utilize these colder temperatures. Our aim was to examine Tricolored Bat roost locations in a WNS-positive site in relation to roost microclimate and other environmental conditions throughout the hibernation season. We conducted monthly censuses of tricolored bats across 2 hibernation seasons (November to March 2020 to 2021 and October to March 2021 to 2022) in a WNS-positive hibernaculum in northwestern South Carolina and recorded skin and adjacent wall temperature, tunnel section, and distance from the entrance for each bat species. We continuously measured hibernacula temperature and relative humidity during both hibernation seasons. Most bats roosted in the back part of the tunnel where temperatures were warmer and more stable, and vapor pressure deficit (VPD) and human disturbance were low. However, >20% of bats roosted in the front, where roost temperatures were significantly colder and VPD was higher but more variable; human disturbance was also higher in this section. The proportion of bats in each tunnel section did not vary among months and we did not find evidence of significant movement to the front section of the tunnel as hibernation progressed based on marked bats; however, bats in the front section roosted higher on the wall suggesting that they may be avoiding human disturbance or predators. Our results support the notion that no optimum hibernation temperature exists for tricolored bats and that high VPD and disturbance are likely important factors driving microsite use. Protection of Tricolored Bat hibernacula that offer a range of microclimates or a network of sites in close proximity that offer different microclimates may be helpful for recovery of this species.

Adaptive sequential three-way decisions for dynamic time warping

Dynamic time warping (DTW) algorithm is widely used in diversified applications due to its excellent anti-deformation and anti-interference in measuring time-series based similarity. However, the high time complexity of DTW restrains the applicability of real-time case. The existing DTW acceleration studies suffer from a loss of accuracy. How to accelerate computation while maintaining satisfying computational accuracy remains challenging. Motivated by sequential three-way decisions, this paper develops a novel model with adaptive sequential three-way decisions for dynamic time warping (AS3-DTW). Firstly, we systematically summarize distance differences under the context of adjacent tripartite search spaces for DTW, and propose five patterns of granularity adjustments of the search spaces. Furthermore, we present the corresponding calculation method of DTW adjacent tripartite search spaces distances difference. Finally, we construct a novel dynamism on adaptively adjusting time warping by combining sequence-based multi-granularity with sequential three-way decisions. Experimental results show that AS3-DTW effectively achieves promising trade-off between computational speed and accuracy on multiple UCR datasets when compared with the state-of-the-art algorithms.

Static analysis-based rapid fire-following earthquake risk assessment method using simple building and GIS information

After the occurrences of large-scale earthquakes, secondary damage (e.g., fire following earthquake) can result in tremendous losses of life, properties, and buildings. To reduce these disaster risks, fire following earthquake assessment methods composed of ignition and fire-burned rate estimation models have been utilized. However, previous methods required for large amounts of building and GIS information, and complex modeling and analysis processes, leading to significant time consumption. This paper proposed a static analysis-based rapid fire following earthquake assessment method using simple information and implemented it in Pohang City, South Korea. Based on previous studies, the best-fit model for the ignition rate estimation was selected, and a cluster-based fire-burned rate estimation model was developed using simple building information (e.g., construction year, building occupancy, story, and total floor area) from the public building database (e.g., building registration data). For the fire-burned rate estimation model, fire-resistant structure types were defined using simple building information, and this was utilized to generate clusters of buildings at a regional level by comparing fire-spread distances for each fire-resistant structure type with adjacent distances among the buildings. This proposed method was applied to Pohang City, South Korea, and validated as follows: (1) the selected ignition rate model predicted similar ignition numbers to the actual reported number (actual number of ignitions = 4 vs. predicted number of ignitions = 3), and (2) the fire-burned rate model estimated fire-burned areas with a marginal difference compared to the fire spread simulation (fire-burned area using the proposed model = 13,703.6 m2 vs. results of fire spread simulation = 16,800.0 m2, with an error of approximately 18%).

Quantum chaotic features of the spin-orbit coupled excitons in disordered two-dimensional insulators.

We study the synergy between disorder (phenomenologically modeled by the introduction of Riesz fractional derivative in the corresponding Schrödinger equation) and spin-orbit coupling (SOC) on the exciton spectra in two-dimensional (2D) semiconductor structures. We demonstrate that the joint impact of "fractionality" and SOC considerably modifies the spectrum of corresponding "ordinary" (i.e., without fractional derivatives) hydrogenic problem, leading to the non-Poissonian statistics of the adjacent level distance distribution. The latter fact is strong evidence of the possible emergence of quantum chaotic features in the system. Using analytical and numerical arguments, we discuss the possibilities to control the above chaotic features using the synergy of SOC, Coulomb interaction, and "fractionality," characterized by the Lévy index μ.

Self-sensing performance of concrete columns using Multi-layer Graphene filled cement-based sensors with different arrangements

The Multi-layer Graphene (MLGs) filled cement-based sensor (GCBS) was developed and applied in the concrete columns. The strain-sensing performance of GCBS was investigated under cyclic and monotonic loading after being embedded in the column. Meanwhile, the influence of embedded location and adjacent sensor distance on the piezoresistive performance of the sensor was discussed. The strain measured by the embedded sensor agreed well with that obtained by LVDTs within the elastic regime. However, the embedded sensor underestimated the concrete strain after stepping into the plastic stage because of the increasing transverse deformation coefficient. Moreover, improper arrangement of the sensor resulted in uneven deformation, generating significant strain differences between the sensor with concrete and increasing prediction deviation. To guarantee the predicting accuracy of the sensor, it is recommended that the embedded position of the sensor from the superficial layer of the column should exceed 25 mm, and the distance between adjacent sensors should not be lower than 107.24 mm.

An artificial potential field approach for event-triggered cooperative control of multiple high-speed trains with free initial states

ABSTRACT In this paper, a multi-algorithm-fusion-based cooperative tracking control strategy is proposed for high-speed trains to achieve the control objectives of reference speed trajectory tracking and adjacent safety distance maintenance simultaneously. First, the multiple high-speed train (MHST) system is formulated as a multi-agent system (MAS) with a virtual leader. Second, a coordination controller that considers the dynamic tracking performance and input saturation is designed by combining the MAS leader-follower consensus algorithm and the improved artificial potential field (APF) method. In addition, within the train-to-train (T2T) communication network, an event-triggered mechanism is introduced in the continuous state transmission process to address the communication channel capacity protection limitation issue. Third, the closed-loop stability of the MHST system is ensured by the comprehensive analysis of a novel log-type Lyapunov function. Finally, the effectiveness of the proposed event-triggered cooperative tracking control strategy is verified through a numerical example of the MHST system on a typical line.

Modeling of fabric sewing break detection based on U-Net network

To solve the problem of false positives and false negatives in the manual detection of fabric sewing breaks, a method of fabric sewing break detection based on the U-Net network is proposed. By detecting the adjacent distance between the characteristic contours of adjacent sewing stitches, the distribution uniformity of sewing stitches in sewing patterns is calculated, and the abnormal detection and traceability of fabric sewing broken threads are realized. First, the U-Net network sewing feature extraction model was trained using sewing images and their corresponding stitching feature annotation maps. Then, the trained network model was used to process sewing image samples to obtain binary stitching feature maps. Second, the stitching feature maps were processed using a closing operation to eliminate residual image noise. On this basis, the template matching algorithm was used to extract the stitching feature contours. Finally, according to the distance between adjacent feature contours, the fabric sewing break detection and abnormality tracing model was constructed. The model is validated by examples, and the results show that the abnormal samples of stitching lines are detected, and the corresponding break positions are given. The overall detection accuracy of the model is 95.75%, indicating that the constructed fabric sewing break detection model is effective.

Graph convolutional network for lithological classification and mapping using stream sediment geochemical data and geophysical data

Lithological mapping plays a vital role in acquiring a comprehensive understanding of subsurface rocks and geological structures. Traditional lithological mapping relies heavily on manual field surveys, with the accuracy of the mapping greatly constrained by the expertise of mappers, and thus this process is commonly slow and costly. In the present study, the graph convolutional network (GCN) method was proposed for efficient and automatic lithological mapping, using various geological survey data (e.g. geochemical and geophysical data). The GCN is not limited by the spatial distribution of sampling data, and hence it can be directly applied to the integrated resampling data that do not adhere to the regular spatial distribution patterns of Euclidean space. To evaluate the potential application of the GCN method in lithological classification and mapping, a case study was conducted in the Maqin region (China). Geochemical and geophysical data were utilized as the basis for lithological classification, as they can provide valuable information on geochemical compositions and physical properties of geological bodies, respectively. The study process was primarily divided into three parts. First, basic pre-processing was conducted on the geochemical data and the geophysical data, including centred log-ratio transformation and resampling. Subsequently, the resampled points were divided into training and testing sets in the proportion of 5.5:1. In the training set, 20% of the points are randomly selected as the validation set. Ultimately, using each resampled point as a node and the integrated geochemical and geophysical data as features, a GCN model and an undirected graph were constructed based on an adjacency distance of 1 km. The graph was employed by the constructed GCN model for lithological classification. The results reveal that the majority of lithological units can be accurately classified with an overall accuracy of 86%, indicating that the GCN model exhibits good applicability in lithological classification.

Enhanced self-collimation effect by low rotational symmetry in hexagonal lattice photonic crystals

In this study, we present the design of a photonic crystal (PC) structure with a hexagonal lattice, where adjustments to the PC unit cell symmetry reveal an all-angle self-collimation (SC) effect. By optimizing opto-geometric parameters, such as the rotational angle of auxiliary rods and adjacent distances, we analyze the SC property in detail, leveraging group velocity dispersion (GVD) and third-order dispersion (TOD) characteristics. We also investigate the relationship between symmetry properties and their influence on dispersion characteristics. Through symmetry manipulation, we gain a comprehensive understanding of the underlying mechanisms governing light collimation and confinement in the proposed configurations. The PC structure with a C1 symmetry group exhibits all-angle SC effect within the range of a/λ = 0.652 and a/λ = 0.668 normalized frequencies, with a bandwidth of Δω/ω c =2.4% Further breaking the symmetry, transforming from C1 to C2 group symmetry enhances the SC bandwidth to Δω/ω c =6.5% and reveals the perfect linear equi-frequency contours (EFC) at two different frequency bands: all angle SC between a/λ = 0.616 and a/λ = 0.344 normalized frequencies in the 4th transverse magnetic (TM) band and between a/λ = 0.712 and a/λ = 0.760 in the 5th TM band. Here, GVD and TOD values of the TM 4th band vary between 7.3 (a/2πc2)–254.3 (a/2πc2) and 449.2 (a2/4π 2c3)–1.3×105 (a2/4π 2c3), respectively. Also, GVD and TOD values of the TM 5th band vary between 182.5 (a/2πc2)–71.3 (a/2πc2) and −24380(a2/4π 2c3)–−9619 (a2/4π 2c3) values, respectively. Additionally, we propose a composite/hybrid PC structure resembling C2 group symmetry, where two auxiliary rods are replaced by rectangular photonic wires with the same refractive index and width equal to the diameter of auxiliary rods. This hybrid structure exhibits an all-angle SC effect with an operating bandwidth of Δω/ω c =11.7%, which displays near-zero GVD and TOD performance and offers enhanced robustness against potential fabrication precision issues.

A Method for Measuring Spatial Information of Area Maps Considering the Diversity of Node–Edge and Gestalt Principles

Existing methods for measuring the spatial information of area maps fail to take into account the diversity of adjacency relations and the heterogeneity of adjacency distances among area objects, resulting in insufficient measurement information. This article proposes a method for measuring area map information that considers the diversity of the node–edge and Gestalt principles. Firstly, this method utilizes the adjacency relations between the Voronoi diagram of area objects to construct an adjacency graph that characterizes the spatial distribution of area objects in area maps. This adjacency graph serves as the information representation of area maps. Secondly, the method selects four characteristic indicators, namely geometric information, node degree, adjacency distance, and adjacency strength, to represent the diversity of nodes and edges in the graph that affect spatial information. Finally, nodes in the adjacency graph are taken as the basic units, and the spatial information of area maps is comprehensively calculated by integrating the four characteristics that represent spatial information. To verify the validity and rationality of the proposed method, a dataset of continuously simplified area maps and a dataset of artificially simulated degrees of randomness were designed to evaluate the performance of the existing method and the method proposed in this paper. The results indicate that the correlation between the measurement results obtained by the method proposed in this paper and the degree of disorder is as high as 0.94, outperforming the existing representative methods. Additionally, the correlation between the measurement results of this method and the degree of simplification reaches 1, indicating that the variation range of the measured values is more consistent with the cognitive assumptions based on artificial simulations compared to the existing methods. The experimental results show that the method proposed in this paper is an effective metric approach for representing spatial information in area maps.

UAV path planning based on a dual-strategy ant colony optimization algorithm

With the rapid development of modern communication and automatic control technologies, unmanned aerial vehicles (UAVs) have increasingly gained importance in both military and civilian domains. Path planning, a critical aspect for achieving autonomous aerial navigation, has consistently been a focal point in UAV research. However, traditional ant colony algorithms need to be improved for the drawbacks of susceptibility to local optima and weak convergence capabilities. Consequently, a novel path planning methodology is proposed based on a dual-strategy ant colony algorithm. In detail, an improved state transition probability rule is introduced, redefining ant movement rules by integrating the state transition strategy of deterministic selection during the iterative process. Additionally, heuristic information on adjacent node distance and mountain height is added to further improve the search efficiency of the algorithm. Then, a new dynamically adjusted pheromone update strategy is proposed. The update strategy is continuously adjusted during the iteration process, which is beneficial to the algorithm’s global search in the early stage and accelerated convergence in the later stage, preventing the algorithm from falling into local optimality and improving its convergence. Based on the above improvements, a new variation of ant colony optimization (ACO) called dual-strategy ACO algorithm is formed. Experimental results prove that dual-strategy ACO has superior global search capabilities and convergence characteristics from four key aspects: path length, fitness values, iteration number, and running time.

Fountain Flow Visualization in Quadrotor Wake Decreasing Rotor Thrust In-Ground Effect

Wake visualizations and thrust measurements of a quadrotor model were conducted to clarify the relationship between thrust and wake flow structure in-ground effects. The adjacent rotor distance, rotor height above ground, and the presence of a plate representing a generic quadrotor centerbody were varied. Thrust decreased when lowering the quadrotor to the ground when the adjacent rotor distance was over 2.2 times the rotor radius. Laser light sheet flow visualization showed quadrotor wake flow structures. Furthermore, visualization using particle image velocimetry showed an averaged vector map of wakes and fountain flow at the center of the quadrotor wake, which caused circulation with rotor passing flow and decreased rotor thrust. The center plate increased the sum of the rotor thrust and plate lift; however, circulation flow formed under the plate and caused the rotor thrust to decrease the in-ground effect. The results clarified that fountain flow development decreased the quadrotor thrust in-ground effect. Reducing the adjacent rotor distance weakened the development of fountain flow in the quadrotor wake and eliminated the decrease in rotor thrust near the ground.

Synergistic engineering of amorphous network and oxygen vacancies in vanadium oxides for enhanced sodium-ion storage

In recent years, vanadium oxide (V2O5) as the anode material of sodium ion batteries (SIBs) has been widely concerned. However, it suffers poor cycling stability derived from the narrow distance between two vanadium atoms in adjacent bilayers. In this work, V2O5 with oxygen vacancies (Vos) and amorphous region (V2O5-Vo-A) was synthesized by pyrolyzing and reducing chitosan-VO3- gel under Ar/H2. Amorphous region can inhibit volume expansion during Na+ deintercalation and improve the pseudocapacitance response. When used as anode materials for SIBs, V2O5-Vo-A electrode has excellent cycling performance (260 mAh g−1 at 0.1 A g−1 after 360 cycles) and superior rate performance (208 mAh g−1 at 1 A g−1). Density functional theory (DFT) calculations reveal that Vos significantly increase charge density at the entire Fermi energy level and adjacent bilayers distance to 4.76 Å, which result enhanced binding energy of Na+ (-1.32 eV) and decreasing volume change of 0.87 % after Na+ adsorption. This research presents a new method to improve the Na+ storage performance of metal oxides, which is expected to be generalized to other metal oxides electrode materials.

Profile reduction of folded transmitarray antenna using multiple feeders

Abstract In this paper, we introduce a novel design for a high-gain, low-profile quad-feed folded transmitarray antenna (FTA) to enable a more compact system. The proposed antenna system consists of a transmitarray, a reflectarray, and four identical planar microstrip U-slot patch antennas placed on the same surface of the reflectarray with an adjacent distance greater than 1λ. To compare the effectiveness of our design, we developed three different antenna array systems with the same aperture size: a single-feed transmitarray antenna (TA) system, the proposed quad-feed FTA system, and a single-feed FTA system. Our experimental results demonstrate that employing four symmetrical feeders with an adjacent distance of 3.2λ effectively reduces the height by about 76.7 % in comparison to the height of a single-feed TA, and by 30 % when compared to the height of a single-feed FTA. We also present the design, fabrication, and testing of a prototype of the proposed quad-feed FTA operating in the Ku-band. The measured results of the prototype confirm the effectiveness of our design.

Multi-functional single cell manipulation method based on a multichannel micropipette

Cell manipulation techniques that provide versatility in handling various cell types and performing diverse manipulations are essential for advancing biological research. This study presents a novel and adaptable approach utilizing a multifunctional micropipette for precise single-cell operations, including three-dimensional (3D) manipulation, trapping, lysis, and aspiration. The multifunctional micropipette comprises two liquid metal-based channels with high electrical conductivity, along with a negative pressure-based aspiration channel. By utilizing the liquid metal electrodes, the system enables the application of electrical stimulation, inducing both dielectrophoretic force and electroporation on cells. Through the implementation of dielectrophoretic force and integration with a 3D-movable stage, single cells can be patterned, manipulated in 3D, accurately trapped, and separated with a minimal adjacent distance of 10 µm. By utilizing the electroporation phenomenon, rapid lysis of suspension cells can be achieved within 50 ms, while adherent cells can be lysed within 200 ms, utilizing a square-wave electrical signal with a frequency of 1 kHz and an amplitude of 40 Vpp. Furthermore, the study explores the impact of electrode size on the lysis of adherent cell groups. Additionally, the utilization of negative pressure for lysate aspiration is also demonstrated. In summary, the reported technique is versatile for single cell manipulation.

A numerical investigation of an indoor dry storage facility on heat transfer

This study conducted a numerical simulation of the dry storage system and indoor facility heat transfer problem. Four standard DSS models have been constructed to investigate the thermal performance. The results show a high-temperature difference found on the surfaces between the sealing canister and the cask, indicating a high thermal resistance in the radial direction. It is also found that the boundary conditions of DSS only affect the indoor facility ambient parameters instead of the inside components. The adjacent pitch distance between DSSs does not significantly change the indoor temperature but affects the view factor. However, convection accounts for 90% of the heat transfer, while radiation only contributes less than 4%. Thus, it is not essential to emphasize the indoor DSS arrangement optimization. This is the first time indoor facility DSS simulation offers suggestions and physical insights into DSS heat transfer, which is beneficial to nuclear energy science and technology.

Analytical model and numerical simulation of relief well adjacent distance considering multi-layer media

Accurate measurement of adjacent well distance (AWD) is the key factor restricting the successful plugging of relief well (RW). Traditional ranging technology can't meet the accuracy requirements of AWD. Fortunately, magnetic ranging technology has shown great superiority in this respect. However, the magnetic ranging algorithm based on low-frequency injected current has always been a difficult problem. Therefore, based on the magnetic ranging principle of low frequency injection current, the propagation law of current in medium is revealed. Considering the effect of mud on current propagation, a multilayer medium model is established to improve the calculation accuracy of current intensity in adjacent casing. Through numerical simulation and experimental comparison, the validity of the analytical model is verified. Analysis results show that the intensity of injected current, the conductivity of medium and the distance between electrode and casing axis have a significant effect on the current of the casing. The radial electric field intensity fluctuates obviously on the interface of the medium. When the distance from the electrode to the casing axis is constant, the magnetic field strength of the measuring point is also affected by the distance from the electrode to the probe pipe and the relative inclination angle. According to the distance between the electrode and the axis of the casing, the optimal distance between the electrode and the probe tube can be obtained, so that the magnetic induction intensity of the measuring point is maximized. The results show that the multi-layer medium model is more suitable for the actual working conditions and the calculation error is minimal.

The Impact of Polymorphism on Charge Transport Properties for Pyrene-FxTCNQ Cocrystals

Research on the charge transport properties of organic semiconductor materials is crucial for the development of organic sensors. In this paper, we investigated the charge transport properties of pyrene-TCNQ, pyrene-F2TCNQ, and pyrene-F4TCNQ cocrystals using the quantum nuclear tunneling model and Monte Carlo simulations to calculate charge mobility. At room temperature, we observed hole mobility values is 0.658 cm2V-1s-1 and electron mobility values is 1.492 cm2V-1s-1, respectively, for pyrene-TCNQ. As the number of F atoms in TCNQ increases, we observed an increase in both hole and electron mobility. Our results showed that the electron to hole mobility ratio was approximately 2.2 for pyrene-TCNQ, 0.6 for pyrene-F2TCNQ, and 0.5 for pyrene-F4TCNQ. Our findings suggest that the introduction of F atoms causes changes in the TCNQ molecular structure, cocrystal stacking mode, adjacent molecular distance, and intermolecular polarization. These changes lead to a modification of the reorganization energy and transfer integrals, ultimately affecting charge transport. Additionally, our results showed that transport along the π-π direction in the three cocrystals exhibited strong anisotropic characteristics, which were much larger than those observed in the other two directions.