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Arranging carbon, boron, and nitrogen atoms in a sp2 network can give rise to tunable electronic properties from insulators (h-BN) to metals (graphene). For semiconductor applications, the construction of a ternary structure (h-BxCyNz) is highly desirable, but its uniform and large-area synthesis has remained a great challenge. This challenge has been attempted by a facile chemical vapor deposition method with a single molecular precursor, N-tri-methyl borazine where boron, carbon, and nitrogen atoms are covalently bonded, onto Ni catalysts in conjunction with the quenching method after the synthesis. The atomic structure closely resembles h-BC2N as revealed by XPS (B:C:N ∼ 1:1.8:1) and nanometer resolution EELS mapping, and the photoluminescence and electroluminescence observed from the h-BC2N film were in agreement, proving its well-established bandgap of 2.15 eV. As a practical application, the utilization of h-BC2N film for 2D light emitting diodes was demonstrated. Though films might have impurities such as small h-BN fragments and h-BxCyNz other than h-BC2N phase, we believe that this work provide a starting point of controlling the ternary BCN compounds that retain sp2 hybridized chemical bonds.

In recent years, as the nation’s racial, ethnic and linguistic diversity grows, there has been an appeal for K-12 classrooms to include more children’s and young adult literature that reflect vario...

Environmentally friendly metal oxide quantum dot (QD) nanostructures have become attractive alternative materials for replacing QDs containing toxic elements of Cd and Pb. Although many attempts have been proposed for optoelectronic applications of hybrid metal oxide QDs with tailored opto-electronic properties, the fabrication of heterogeneous QD–fullerene hybrids as an emissive material has been studied little for optoelectronic devices. Herein, we report the preparation of ZnO–fullerene C70 (ZnO–C70) QDs by a facile chemical reaction with a zero length linker and demonstrate whitish light-emitting diodes by fullerene induced multicolor emission from the ZnO–C70 QD heterostructure. The electroluminescence (EL) is attributed to three new emission features in the visible region that originate from the electron transitions from three split lowest unoccupied molecular orbital levels of C70 molecules to the valence band of ZnO QDs. Compared with photoluminescence, the EL emission was red-shifted by 50–130 meV due to the interaction between ZnO–C70 QDs in the solid state. The energy levels of C70 were also suitably aligned to those of ZnO QDs with a lower electron transfer barrier of 0.22 eV, which offers an advantageous route for electron transport. Consequently, the environmentally friendly ZnO–C70 QDs with extraordinary properties promise great potential for use as novel encapsulating materials in the field of opto-electronic applications adopting QDs.

We present a multiwavelength study of the double radio relic cluster A1240 at z=0.195. Our Subaru-based weak lensing analysis detects three mass clumps forming a ~4 Mpc filamentary structure elongated in the north-south orientation. The northern ($M_{200}=2.61_{-0.60}^{+0.51}\times10^{14} M_{\odot}$) and middle ($M_{200}=1.09_{-0.43}^{+0.34}\times10^{14} M_{\odot}$) mass clumps separated by ~1.3 Mpc are associated with A1240 and co-located with the X-ray peaks and cluster galaxy overdensities revealed by Chandra and MMT/Hectospec observations, respectively. The southern mass clump ($M_{200}=1.78_{-0.55}^{+0.44}\times10^{14} M_{\odot}$), ~1.5 Mpc to the south of the middle clump, coincides with the galaxy overdensity in A1237, the A1240 companion cluster at z=0.194. Considering the positions, orientations, and polarization fractions of the double radio relics measured by the LOFAR study, we suggest that A1240 is a post-merger binary system in the returning phase with the time-since-collision ~1.7 Gyr. With the SDSS DR16 data analysis, we also find that A1240 is embedded in the much larger-scale (~80 Mpc) filamentary structure whose orientation is in remarkable agreement with the hypothesized merger axis of A1240., Replaced with version accepted for publication in ApJ, including minor revisions after reviewer's report. 23 pages, 14 figures, 2 tables

Harsh oxidation of 1 nm single-walled carbon nanotubes (SWCNTs) can lead to fatal defect structures, which can jeopardize their mechanical and electrical performances. Here, we show the structural recovery of highly oxidized SWCNTs (Ox-SWCNTs), which were rapidly (within 1 h) oxidized by kneading without forming failure-causing defects inspired by flour dough. The rational oxidation of SWCNTs by kneading debundled the SWCNTs and led to obtaining thermodynamically stable SWCNT solutions in water or even in alcohol without dispersant molecules. Importantly, the structure of the Ox-SWCNTs could be recovered by chemical, thermal, photothermal, or solvothermal reduction, enhancing the electrical conductivity of the Ox-SWCNT films from ∼100 to ∼1000 S cm–1. These Ox-SWCNTs and chemically reduced Ox-SWCNTs showed high performance in supercapacitors and Li-ion batteries as electrochemical conductors, respectively.

In this study, the rapid synthesis of graphene via chemical vapor deposition (CVD) using liquefied petroleum gas (LPG), a common and low-cost carbon source majorly composed of butane and propane, as the precursor is investigated. For the synthesis of high-quality graphene, the growth conditions are optimized by controlling CVD parameters such as growth time, temperature, gas amount, and flow rate. Thus, graphene is successfully obtained from LPG in a short time. This synthesis is 10 times faster than that the conventional synthesis using methane as the carbon source. In the X-ray photoelectron spectra, the rapidly grown graphene samples obtained from LPG show small S2p signals due to the presence of few tens ppm ethanethiol in commercial LPG. In addition, graphene is synthesized using a hydrogen and LPG mixture to investigate the quality of graphene. Both samples are characterized by their peak positions and full width at half maximum values of the G and 2D peaks in the Raman spectra and Dirac points in the electrical measurements. In particular, the Dirac points of the graphene sample obtained with a growth time of 1 min sample appear around −22 VG and the sample's mobility is about 1600 cm2/V⋅s.

The task allocation problem has been a challenging issue in swarm robotic systems. In this paper, we handle dynamic task allocation in the object foraging task, where multiple robots are supposed to collect various objects in parallel during a given time span. We propose a decentralized strategy of the response threshold model without any communication among robots. Here, we introduce a task selection probability function for each robot to balance the task demands with robots working on tasks. The method can produce varying tendencies to tasks by changing the response thresholds given in the task selection probability function. With this property, each robot can select its own task among all available tasks, by regulating the response threshold values. This ultimately promotes a desired task distribution in a group level and reduces the number of task changes. Our approach suggests that the response threshold of robot is updated based on what objects have been observed recently and what tasks have been done by its neighboring robots observed in the local surrounding area. We provide a convergence analysis that the system can stochastically converge to the equilibrium of the desired task distribution. The method is effective even when only local information about the environment is given to individual robots. The suggested method is tested with a simulation of multiple robots taking the foraging task, and a dynamic task allocation process is demonstrated.

Reduced graphene oxide (rGO) has potential as a mass-producible and cost-effective substitute for graphene, but displays poor crystal quality due to various types of structural defects. Though many attempts have been reported to improve the quality of rGO, most of them require sophisticated equipment or severe conditions such as toxic chemicals, high temperature, and electron beam or plasma treatment in ultra-high vacuum (UHV) conditions. Here, we report a mild and simple solution-based healing method for obtaining high-quality rGO, with this method involving the use of a simple camera flash light treatment and the nontoxic chemicals l -ascorbic acid and ethanol. Exposing a GO solution containing l -ascorbic acid and ethanol to the flash light irradiation for a short amount of time (

Background Intraocular surgery and reconstructive surgery are challenging microsurgery procedures that require two types of motion: precise motion and larger motion. To effectively perform the requisite motion using a robot, it is necessary to develop a manipulator that can adjust the scale of motion between precise motion and less precise, yet larger motion. Aims In this paper, we propose a novel microsurgery robot using the dual delta structure (DDS) to mechanically scale the motion to seamlessly adjust between precise and larger motion. MATERIALS & METHODS: The DDS forms a lever mechanism that enables the motion scaling at the end-effector using two delta platforms. Seamless scale adjustment enables the robot to effectively perform various surgical moves. Results A prototype robot system was developed to validate the effectiveness of the DDS. The experiment results in various scale settings validated the scaling mechanism of the DDS. Conclusion Through a graphical simulation and measurement experiment, the robot's precision level and attainable workspace has been confirmed adequate for intraocular and reconstructive surgery.

We investigate the formation of jellyfish galaxies using radiation-hydrodynamic simulations of gas-rich dwarf galaxies with a multi-phase interstellar medium (ISM). We find that the ram-pressure-stripped (RPS) ISM is the dominant source of molecular clumps in the near wake within 10 kpc from the galactic plane, while in-situ formation is the major channel for dense gas in the distant tail of the gas-rich galaxy. Only 20% of the molecular clumps in the near wake originate from the intracluster medium (ICM); however, the fraction reaches 50% in the clumps located at $80\,{\rm kpc}$ from the galactic center since the cooling time of the RPS gas tends to be short due to the ISM--ICM mixing ($\lesssim$ 10 Myr). The tail region exhibits a star formation rate of $0.001-0.01\,{\rm M_{\odot}\,yr^{-1}}$, and most of the tail stars are born in the stripped wake within 10 kpc from the galactic plane. These stars induce bright H$\alpha$ blobs in the tail, while H$\alpha$ tails fainter than $6\times10^{38}\,{\rm erg\,s^{-1}\,kpc^{-2}}$ are mostly formed via collisional radiation and heating due to mixing. We also find that the stripped tails have intermediate X-ray to H$\alpha$ surface brightness ratios (1.5$\lesssim F_{\rm X}/F_{\rm H\alpha}\lesssim$20), compared to the ISM ($\lesssim$1.5) or pure ICM ($\gg$20). Our results suggest that jellyfish features emerge when the ISM from gas-rich galaxies is stripped by strong ram pressure, mixes with the ICM, and enhances the cooling in the tail., Comment: 19 pages, 15 figures; Accepted for publication in ApJ

A521 has been a subject of extensive panchromatic studies from X-ray to radio. The cluster possesses a number of remarkable features including a bright radio relic with a steep spectrum, more than three distinct galaxy groups forming a filament, and two disturbed X-ray peaks at odds with the distant position and tilted orientation of the radio relic. These several lines of evidence indicate a complex merger. In this paper, we present a multi-wavelength study of A521 based on Subaru optical, Hubble Space Telescope infrared, Chandra X-ray, GMRT radio, and MMT optical spectroscopic observations. Our weak-lensing (WL) analysis with improved systematics control reveals that A521 is mainly composed of three substructures aligned in the northwest to southeast orientation. These WL mass substructures are remarkably well-aligned with the cluster optical luminosity distribution constructed from our new enhanced cluster member catalog. These individual substructure masses are determined by simultaneously fitting three NFW profiles. We find that the total mass of A521 modeled by the superposition of the three halos is $13.0_{-1.3}^{+1.0} \times 10^{14}M_{\odot}$, a factor of two higher than the previous WL measurement. With these WL mass constraints combined with X-ray and radio features, we consider two merging scenarios, carry out the corresponding numerical simulations, and discuss strengths and weaknesses of each case., 15 pages, 11 figures, Accepted to ApJ

Although a merging galaxy cluster is a useful laboratory to study many important astrophysical processes and fundamental physics, only limited interpretations are possible without careful analysis of the merger scenario. However, the study is demanding because a thorough comparison of multi-wavelength observations with detailed numerical simulations is required. In this paper, we present such a study for the off-axis binary merger A115. The system possesses a number of remarkable observational features, but no convincing merger scenario, explaining the shape and location of the radio relic in harmony with the orientation of the cometary X-ray tails, has been presented. Our hydrodynamical simulation, with adaptive mesh refinement, suggests that the cometary X-ray tail of A115 might be a slingshot tail and can arise $\sim0.3$ Gyrs after the impact and before the two subclusters reach their apocenters. This scenario can predict the location and orientation of the giant radio relic, which is parallel to the northern X-ray tail. In addition, our study indicates that diffusive shock acceleration alone cannot generate the observed radio power unless aided by stronger magnetic fields and/or more significant presence of fossil electrons., 14 pages, 11 figures, ApJ in press

The ASKAP-EMU survey is a deep wide-field radio continuum survey designed to cover the entire southern sky and a significant fraction of the northern sky up to $+30^{\circ}$. Here, we report a discovery of a radio relic in the merging cluster SPT-CL 2023-5535 at z=0.23 from the ASKAP-EMU pilot 300 sq. deg survey (800-1088 MHz). The deep high-resolution data reveal a $\sim2$ Mpc-scale radio halo elongated in the east-west direction, coincident with the intracluster gas. The radio relic is located at the western edge of this radio halo stretched $\sim0.5$ Mpc in the north-south orientation. The integrated spectral index of the radio relic within the narrow bandwidth is $\alpha^{\scriptstyle \rm 1088~MHz}_{\scriptstyle \rm 800~MHz}=-0.76 \pm 0.06$. Our weak-lensing analysis shows that the system is massive ($M_{200}=1.04\pm0.36\times 10^{15} M_{\odot}$) and composed of at least three subclusters. We suggest a scenario, wherein the radio features arise from the collision between the eastern and middle subclusters. Our discovery illustrates the effectiveness of the ASKAP-EMU survey in detecting diffuse emissions in galaxy clusters and when completed, the survey will greatly increase the number of merging cluster detections with diffuse radio emissions.

The applications of solution-exfoliated graphene oxide (GO) as an electrical/electrochemical conductor require rational design–based approaches. Herein, we show that reduced GO nanosheets with highly ordered or nanoporous structures can be fabricated by treatment of graphite oxide (GrO) having variable-oxidation-degree with hot KOH solution. As model systems, GrO powders fabricated by modified Brodie and Hummers methods (B-GrO and H-GrO, respectively) were exfoliated into GO in alkaline solutions (to afford B-KGO and H-KGO, respectively), followed by 2.5-h refluxing at 100 °C. Notably, B-KGO was exceptionally resistant to hot KOH solution, whereas H-KGO was partially reduced under these conditions, as confirmed by 13C solid-state NMR, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy analyses. Moreover, reduced B-KGO featured highly ordered structures, whereas reduced H-KGO contained nanopores resulting from low-temperature activation in KOH solution. These extraordinary reactions of KGO nanosheets were translated into different electrical properties of reduced KGO nanosheets and different rheological properties of the corresponding pastes.

Objectives To assess the correlation of resected and ischaemised volume (RAIV), which is preoperatively calculated volume of nephron loss (VNL), with the amount of postoperative renal function (PRF) decline after minimally invasive partial nephrectomy (PN) in a multi-institutional dataset. Subjects and Methods We identified 348 patients from March 2005 to December 2013 at six institutions. Data on all cases of laparoscopic (n = 85) and robotic PN (n = 263) performed were retrospectively gathered. Univariable and multivariable linear regression analyses were utilised to identify the associations between various time points of PRF and RAIV as a continuous variable. Results Mean RAIV was 24.2 ± 29.2 cm3. Mean preoperative eGFR and eGFRs at postoperative day 1, 6 months and 3 years follow-up was 91.0 and 76.8, 80.2 and 87.7 ml/min per 1.73 m2, respectively. In multivariable linear regression analysis, the amount of changes in PRF in long-term follow-up were significantly correlated with RAIV (β = 0.261, β = 0.165, β = 0.260 at postoperative day 1, 6 months and 3 years follow-up, respectively). This study has the limitation of its retrospective nature. Conclusion Preoperatively calculated RAIV significantly correlates with the amount of changes in PRF during long-term follow-up. RAIV could lead our research to the level of prediction of the amount of PRF decline. RAIV provides appropriate evidence to explain the technical advantages of emerging techniques. This article is protected by copyright. All rights reserved.

Chemical doping of transition metal dichalcogenides (TMDCs) has drawn significant interest because of its applicability to the modification of electrical and optical properties of TMDCs. This is of fundamental and technological importance for high-efficiency electronic and optoelectronic devices. Here, we present a simple and facile route to reversible and controllable modulation of the electrical and optical properties of WS2 and MoS2via hydrazine doping and sulfur annealing. Hydrazine treatment of WS2 improves the field-effect mobilities, on/off current ratios, and photoresponsivities of the devices. This is due to the surface charge transfer doping of WS2 and the sulfur vacancies formed by its reduction, which result in an n-type doping effect. The changes in the electrical and optical properties are fully recovered when the WS2 is annealed in an atmosphere of sulfur. This method for reversible modulation can be applied to other transition metal disulfides including MoS2, which may enable the fabrication of two-dimensional electronic and optoelectronic devices with tunable properties and improved performance.

Low-pressure chemical vapor deposition of graphene has been investigated on various Pt substrates such as e-beam deposited films, sputtered films, and polycrystalline foils. High temperature sputtering is found to be crucial in growing single layer graphene on Pt. It gives highly (111)-oriented crystallization with a significant reduction of dewetting in Pt films, in contrast to e-beam deposited Pt films. Graphene grown on high temperature sputtered Pt films is free of micro-sized multilayer graphene islands normally observed in graphene grown on polycrystalline Pt foils. This indicates that using Pt thin films can effectively suppress the multilayer graphene growth by carbon segregations and precipitations from the Pt bulk. Growth of single layer graphene is demonstrated on Pt films with a thickness down to 25 nm. Effects of the Pt substrates on the as-grown graphene have been investigated. An XY plot of the Raman G and 2D bands in graphene shows a correlation with the surface facet orientations of the Pt substrates measured by electron backscatter diffraction. With a general red shift of the G band distributions, a blue shift of the 2D band distributions is observed, which goes as high as ∼2750 cm−1 in graphene grown on Pt (111) films.

We report an effective post-treatment method to improve the mechanical and electrical properties of carbon nanotube fibers (CNTF) by using an aryl radical coupling reaction of polymers. The modified CNTF were analyzed using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). The results demonstrated that chemical cross-links formed by Poly( p -iodostyrene) (PIS) inside the CNTF affected the mechanical and electrical properties. Compared with pristine CNTF, the cross-linked CNTF using PIS exhibited about 160%, 200% and 53% increased tensile strength (1.4 N/tex), elastic modulus (103 N/tex) and electrical conductivity (1480 S/cm), respectively. This post-treatment method using polymer impregnation followed by thermochemical reaction may provide a general strategy for enhancing both mechanical and electrical properties of directly spun CNTFs.

We measured Drude absorption of gated CVD graphene using far-infrared transmission spectroscopy, and determined carrier scattering rate (g) as function of the varied carrier density (n). The n-dependent g(n) was obtained for a series of conditions systematically changed as (10 K, vacuum) -> (300 K, vacuum) -> (300 K, ambient pressure), which reveals that (1) at low-T, charged impurity (=A/sqrt(n)) and short-range defect (=B*sqrt(n)) are the major scattering sources which constitute the total scattering g=A/sqrt(n)+B*sqrt(n), (2) among various kinds of phonons populated at room-T, surface polar phonon of the SiO2 substrate is the dominantly scattering source, (3) in air, the gas molecules adsorbed on graphene play a dual role in carrier scattering as charged impurity center and resonant scattering center. We present the absolute scattering strengths of those individual scattering sources, which provides the complete map of scattering mechanism of CVD graphene for the first time. This scattering map allows us find out practical measures to suppress the individual scatterings, the mobility gains accompanied by them, and finally the ultimate attainable carrier mobility for CVD graphene., 14 pages, 6 figures

An effective method to fabricate high-performance oxygen gas barrier films by alternately stacking negatively charged graphene oxide (GO) and positively charged aminno-ethyl-functionalized GO (AEGO) on PET substrates was suggested. The GO was prepared by the Hummer's method using natural graphite powder and the AEGO was synthesized by a carbodiimide reaction of the GO. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the introduction of functional groups of GO and AEGO. GO/AEGO/GO layers on a PET film were formed through spray coating method. The gas barrier and mechanical properties of the film were examined. One layer of GO/AEGO/GO stacked film coated on a PET substrate showed an oxygen permeability of 0.01 cc/m 2 day atm, which is 10 3 times lower than that of pure PET. The results corresponding to tensile strength and modulus of the film revealed an increase of approximately 61 and 41% compared to those of pure PET, respectively.

We have investigated the microstructural and electrical properties of Cu-germanides formed by the deposition of Cu on Ge wafer, followed by rapid thermal annealing (RTA) process at the temperatures in the range of 300–700 °C. Regardless of RTA temperature, the Cu3Ge was the only phase formed as a result of solid-state reaction between Cu and Ge driven by RTA process. The RTA temperature dependency of specific contact resistivity of Cu3Ge was explained in terms of its structural evolution caused by RTA process. The RTA process at 400 °C led to the formation of Cu3Ge film having highly uniform surface and interface morphologies, allowing the minimum value of the specific contact resistivity. The samples annealed above 500 °C underwent the severe structural degradation of Cu3Ge, resulting in a rapid increase in the specific contact resistivity. After RTA at 700 °C, pyramidal Cu3Ge islands standing on a corner, distributed along Ge direction were formed with epitaxial relationship on underlying Ge.

Boron nitride nanosheet/copper (BNNS/Cu) nanocomposites were fabricated using a molecular-level mixing process. This process was facilitated by electrostatic interactions between negatively charged functional groups on the BNNSs and Cu metal precursor ions. The mixing process induced the formation of oxygen (O)-mediated bonding between BNNSs and the Cu matrix, which enabled enhanced dispersion of BNNSs and interfacial bonding with the Cu matrix. The mechanical properties of the resulting nanocomposite material, including the yield strength, tensile strength, and modulus, were greatly improved with incorporation of only a small amount of BNNSs using the molecular-level mixing process. The strengthening effect of BNNSs was attributed to a combination of a small contribution from grain size refinement effect and a major contribution from load transfer effect. This extraordinary load transfer strengthening, supported by modeling, is attributed to O-mediated interfacial bonding between the BNNSs and Cu. High-resolution transmission electron microscopy revealed the formation of an amorphous interphase between the BNNSs and the Cu matrix. This O-rich phase may have contributed to the strengthening effect of the BNNSs. The BNNS/Cu nanocomposite showed excellent high-temperature mechanical properties. These superior mechanical properties of the nanocomposite material suggest applications in various structural materials, including those requiring exposure to high temperatures.

The scheduling problems in factory domain applications usually involve many parallel machines, with each machine capable of processing several tasks. In most cases, changing the current machine state to another state to process a different task incurs additional material costs and time. If the overall system can maintain the expected performance, minimizing these state changes is very beneficial, and agent-based approaches inspired by the task allocation strategies of several social insects have gained increasing attention as solutions. The basic concept is based on the stimulus-threshold relation, and an individual agent determines whether it performs a given task or not based on two sets of terms, the environmental external stimuli for the task and the internal threshold values of all possible tasks. In this approach, selecting appropriate threshold values is directly related to the overall system performance, and we present a pheromone-based approach to obtain appropriate threshold values. Each agent maintains a limited, constant-sized task history queue of recently processed tasks, and the information of each agent is individually used to calculate the threshold values of tasks. Based on various experimental results, we show that the performance of the proposed method is comparable to those of other conventional methods.

Temperature-induced variation in magnetic properties for cobalt-based metallic glass was investigated. The formation of metastable nanocrystalline phases prior to complete devitrification and their effect on magnetic properties for Co72B19.2Si4.8Cr4 metallic glass was studied. The nature, shape, and distribution of the intermediate nanocrystalline phases were characterized using transmission electron microscopy and x-ray diffraction. A drastic change in magnetic properties was found in going from a fully amorphous state to different stages of nanocrystallization. The coercivity changes from amorphous soft magnetic state (H c ~ 0.12 Oe) to a nanocrystalline-dispersed hard magnetic state (H c ~ 187 Oe), with no significant change in saturation magnetization. This suggests potential use in futuristic magnetic switches, fluxgate sensors, and electromagnetic shielding devices.

This paper presents a distributed coordination methodology for multi-robot systems, based on nearest-neighbor interactions. Among many interesting tasks that may be performed using swarm robots, we propose a biologically-inspired control law for a shepherding task, whereby a group of external agents drives another group of agents to a desired location. First, we generated sheep-like robots that act like a flock. We assume that each agent is capable of measuring the relative location and velocity to each of its neighbors within a limited sensing area. Then, we designed a control strategy for shepherd-like robots that have information regarding where to go and a steering ability to control the flock, according to the robots’ position relative to the flock. We define several independent behavior rules; each agent calculates to what extent it will move by summarizing each rule. The flocking sheep agents detect the steering agents and try to avoid them; this tendency leads to movement of the flock. Each steering agent only needs to focus on guiding the nearest flocking agent to the desired location. Without centralized coordination, multiple steering agents produce an arc formation to control the flock effectively. In addition, we propose a new rule for collecting behavior, whereby a scattered flock or multiple flocks are consolidated. From simulation results with multiple robots, we show that each robot performs actions for the shepherding behavior, and only a few steering agents are needed to control the whole flock. The results are displayed in maps that trace the paths of the flock and steering robots. Performance is evaluated via time cost and path accuracy to demonstrate the effectiveness of this approach.