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A vital objective in the wetting of Au deposited on chemically heterogeneous oxides is to synthesize a completely continuous, highly crystalline, ultrathin-layered geometry with minimized electrical and optical losses. However, no effective solution has been proposed for synthesizing an ideal Au-layered structure. This study presents evidence for the effectiveness of atomic oxygen-mediated growth of such an ideal Au layer by improving Au wetting on ZnO substrates with a substantial reduction in free energy. The unexpected outcome of the atomic oxygen-mediated Au growth can be attributed to the unconventional segregation and incorporation of atomic oxygen along the outermost boundaries of Au nanostructures evolving in the clustering and layering stages. Moreover, the experimental and numerical investigations revealed the spontaneous migration of atomic oxygen from an interstitial oxygen surplus ZnO bulk to the Au-ZnO interface, as well as the segregation (float-out) of the atomic oxygen toward the top Au surfaces. Thus, the implementation of a 4-nm-thick, two-dimensional, quasi-single-crystalline Au layer with a nearly complete crystalline realignment at a mild temperature (570 K) enabled exceptional optoelectrical performance with record-low resistivity (7.5 × 10

Oxyapatite[Ca2Nd8(SiO4)6O2] glass-ceramics have been suggested as wasteforms for the immobilisation of rare-earth radioactive nuclides because of their high waste-loading capability and good chemical durability. In particular, a partitioning effect is predicted to contribute to an enhancement of corrosion resistance in glass-ceramics compared with that of conjugate glasses of the same composition. Because rare-earths are inherently insoluble nuclides, detection of changes in corrosion behavior between glass-ceramics and conjugate glasses under normal conditions is not easy. In this study, therefore, we revealed the partitioning effect by exposing glass-ceramics and glasses to solution of pH 2, 7 and 10 at 90 °C for 20 d. In addition, we proposed the corrosion mechanism for oxyapatite glass-ceramics under various corrosion conditions. Especially, the glassy phase dissolved first, followed by the oxyapatite phase during pH 7 corrosion.

2D Ballbot is an actual under-actuated system with second-order nonholonomic velocity constraints and input coupling case where only control input is employed to control two outputs of the system. Controlling such a system is not easy because it faces many changelings including nonlinearities, external disturbances, and uncertainties. This study proposed a robust control system for a Ballbot mobile robot. The proposed control scheme is constructed using the hierarchical sliding mode control technique. The kinematics and dynamics of the Ballbot are derived. A Lyapunov function is used to prove the stability of the closed-loop control system. The stabilizing and transferring problems are investigated through several simulations and experiments by using the actual Ballbot platform.

The desire to enhance the efficiency of organic light-emitting devices (OLEDs) has driven to the investigation of advanced materials with fascinating properties. In this work, the efficiency of top-emission OLEDs (TEOLEDs) is enhanced by introducing ampicillin microstructures (Amp-MSs) with dual phases (α-/β-phase) that induce photoluminescence (PL) and electroluminescence (EL). Moreover, Amp-MSs can adjust the charge balance by Fermi level (E

Structure engineering is essential for manipulating the chemical, electrical, and optical properties of Au. However, it is challenging to design nanoscopic structures because no effective method is available to deviate from the intrinsic evolution behavior during and after synthesis via vapor deposition. Here, we propose an approach that utilizes the oxidation-induced clustering and layering of Au due to the strong O interference at the outmost surfaces of nanoscopic Au geometries. This promotes the evolution of Au clusters and layers that are highly wetted on their oxide supports. A 4-nm-thick epitaxial Au layer eventually evolved from the proposed growth mode, simultaneously exhibiting higher optical transparency than Ag, a near-bulk resistivity of 8 × 10−8 Ω m, and extreme resilience to chemical corrosion and mechanical deformation. This result provides a definite solution to transparent metal electrodes that are highly vulnerable to degradation in ambient and working environments.

The effect of ultraviolet-ozone (UVO) irradiation on amorphous (am) SnO2 and its impact on the photoconversion efficiency of MAPbI3-based perovskite solar cells were investigated in detail. UVO treatment was found to increase the amount of chemisorbed oxygen on the am-SnO2 surface, reducing the surface energy and contact angle. Physicochemical changes in the am-SnO2 surface lowered the Gibbs free energy for the densification of perovskite films and facilitated the formation of homogeneous perovskite grains. In addition, the Fermi energy of the UVO-treated am-SnO2 shifted upwards to achieve an ideal band offset for MAPbI3, which was verified by theoretical calculations based on the density functional theory. We achieved a champion efficiency of 19.01 % with a statistical reproducibility of 17.01 ± 1.34 % owing to improved perovskite film densification and enhanced charge transport/extraction, which is considerably higher than the 13.78 ± 2.15 % of the counterpart. Furthermore, UVO-treated, am-SnO2-based devices showed improved stability and less hysteresis, which is encouraging for the future application of up-scaled perovskite solar cells.

Crawler excavators are important, utilitarian machines in construction industries. Special features of the chain and chassis allow them to operate and move on unstable ground. The shock motions of the links, which coincide with the changes of the forces impacting the foundation, create vibrations within the entire system. The highest level of vibrations appears when the boom moves, as it holds the robotic excavator's entire actuator with large mass and moment of inertia. These undesired fluctuations cause system instability, driver discomfort, reduced operating efficiency, and increased energy consumption. In this study, a hierarchical sliding mode control focusing on boom movement is designed based on the system dynamic model. This controller allows the boom to move precisely with a slight fluctuation angle of the main body, even while the other links are moving using a parameter estimator. Maintaining stable boom movements significantly simplifies arm and bucket control. The effectiveness of the entire work is investigated by numerical simulation and implementation results on a small-scale hydraulic excavator.

Cable-driven parallel robots (CDPRs) are vulnerable to vibration due to the inevitable flexible properties of the cables. Thus, vibration analysis is critical for CDPR’s operation in which highly accurate motion is required. However, most of the current methods related to vibration analysis of CDPRs rely on simple spring models which have limitations in their performance and complexity that are not general to analyze the vibration of various CDPRs. Hence, accurate, simple and general approaches for vibration analysis in CDPRs are need. To solve this problem, this paper presents the finite element method (FEM) and the modified analytical method to analyze the vibration of CDPRs. To validate these methods, free vibration analysis was conducted using the proposed methods for the planar and spatial cable-driven parallel robots. The natural frequencies of these two CDPRs were computed by the proposed two methods and compared with those of the commercial software, SAP2000. The solutions obtained by the FEM and the modified analytical models turned out to be close to SAP2000’s results, thereby verifying the validity of the proposed methods.

Modern buildings are designed with wheelchair accessibility, giving an opportunity for wheeled robots to navigate through sloped areas while avoiding staircases. Nonetheless, working safely and autonomously in uneven or unstructured environments is still challenging for mobile robots. Herein, we propose the use of a point cloud treatment and Monte Carlo localization in an algorithm for 3D localization of a mobile robot in uneven and unstructured environments. The point cloud treatment consists of projecting the acquired 3D point cloud and generated 2D features. These features are used to recreate an occupancy map. To perform localization in real-time, the robot systems use the occupancy map and 2D features as input in conjunction with the Monte Carlo algorithm.

Hydraulic crawler excavators have been widely used for construction in industry, mining, and agriculture because of their special ability to work on weak soil support. However, the elastic properties of the ground increase the undesired vibrations of the entire operating machine. These oscillations significantly influence the working productivity, the level of fuel expenditure, and the comfort of the driver. There have been many works addressing this problem, although they mainly focus on mechanical dampers. Considering the system from robotic and control aspects, this study presents a new approach to deal with the abovementioned problem. A controller design, which uses a combination of feedback linearization and sliding mode control, is proposed based on a dynamic model. This control law reduces the vibrations of the system working on an elastic foundation, while also allowing for accurate tracking performance of the links. This control law is applied to a small-scale platform to investigate its feasibility for practical applications.

A ridable ballbot has unstable underactuated dynamics with nonholonomic velocity constraints and input coupling case. Such a robot can carry people and move in any direction on the floor. In this study, a pseudo-2D dynamic model of the ridable ballbot is derived. An improved nonlinear double-loop control system combined with the partial feedback linearization (PFL) technique is proposed for the ridable ballbot, which allows it to balance and transfer. Feedforward compensation is added to the controller to consider uncertainties, friction, and disturbances. Numerical simulations and experiments show the validity of the PFL double-loop control based on the pseudo-2D dynamic model.

In this study, a novel multiphase converged control structure with a switching mechanism is established based on the fundamentals of the fast-terminal sliding mode. This control structure achieves an excellent performance in a nonlinear dynamic system, and its primary objective is to control the piston trajectory in an innovative electrohydraulic, pneumatic, and mechanical hybrid system. This work focuses on abrupt gain-scheduled acceleration, which has been rarely studied in the literature but has increasingly diverse high-technology applications across various industries. The greatest challenge lies in the sensitivity and instability of the system during a sudden actuator acceleration. Moreover, the system parameter uncertainties and external disturbances strongly influence the degree of control of the system. By inheriting the robustness and fast convergence properties of sliding-mode algorithms, the proposed control law not only guarantees a finite-time convergence of tracking errors to their origin but also reduces the impact of composite disturbances in an extremely rapid experimental process. The effectiveness of the proposed structure is analyzed via numerical simulations and industrial implementation.

The quest to improve the performance of organic light-emitting diodes (OLEDs) has led to the exploration of new materials with properties like interfacial dipole, excitons generation, and bandgap alignment. Here, we exploit these strategies by investigating the interaction of the antibiotic ampicillin with a widely used optoelectronic material, to fabricate state-of-the-art OLEDs. The charge distribution on the ampicillin molecule facilitates the generation of an interfacial dipole with a large magnitude. The optimum fusion of the two materials provides an enhanced bandgap alignment, charge balance and J/H-aggregated excitons. Values of current efficiency (120 cdA−1), external quantum efficiency (~35%) and power efficiency (70 lmW−1) are demonstrated. The cross-evaluation of performance with penicillin devices indicates the significance of ampicillin’s specific molecular structure in improving performance. The detailed investigations demonstrate that ampicillin has superior optoelectronic properties with high potential to contribute extensively in OLEDs and photovoltaics. The need to move away from silicon-based semiconductors for the electronic industry has yielded significant developments in the use of organic materials for devices. The authors present a method to enhance organic light-emitting diodes (OLEDs) performance by adding a common antibiotic, ampicillin into a common organic semiconductor and achieving a maximum external quantum efficiency of 35%.

A ridable ballbot, a personal robot, is an underactuated system. The four state variables of the ball motion and body motion are controlled by two input signals acting on the ball. Euler–Lagrange equation is applied to obtain the dynamic model of the ridable ballbot. On the basis of this dynamic model, a nonlinear controller is analyzed and designed to control balancing and transferring of the robot. The nonlinear control scheme is proposed based on the combination of two control design techniques: (i) partial feedback linearization, which is designed to maintain the body in the upright position; and (ii) sliding mode control, which provides robust control in ball motion on the floor against model imprecision, uncertainty of system parameters and friction, and external disturbances. These two control mechanisms are successfully merged into a combined controller. Numerical and experimental results indicate the effectiveness of the combined controller and proposed a dynamic model. The control algorithm asymptotically stabilizes all system responses.

Ballbot is a robot that can transfer to a given position while maintaining a self-balanced upright posture on a spherical ball. This paper proposes a nonlinear control of a ballbot using three omnidirectional wheels in the driving mechanism. Assuming a small swing angle for balance, the full dynamics of the ballbot can be decomposed into three, which are two underactuated dynamics for two orthogonal vertical planes and the fully actuated dynamics for one horizontal plane. The passivity of closed-loop systems of vertical planes is derived from the modified potential energy function. The proposed controller is designed to control the balancing and transferring of the system based on Lyapunov theory and the passivity of the system. A proportional-derivative feedforward controller is applied to regulate the heading motion in the horizontal plane. Experiments are performed with a real ballbot system to validate the effectiveness of system modeling and to show the controllability of the proposed algorithm.

In this study, we propose a nonlinear double-loop control system for a ridable ballbot. An improved nonlinear double-loop control technique based on double-loop control scheme and sliding mode technology is used, and the inner-loop consists of proportional–integral feedback plus feedforward control. A sliding mode control enables the ridable ballbot to balance and transfer on the floor. Feedforward compensation has been added for the stability of the ballbot. As a result, the control system can stabilize all state variables of the ballbot system despite the uncertainties of the system parameters such as model, friction, and external disturbances, and relatively large body inertia. Experiments demonstrate the effectiveness of the proposed control system and the performance validation of the nonlinear double-loop control.

Different WO3 facets have different surface energies and electronic structures, and exhibit different water oxidation abilities and photocatalytic performance as a result. Because of the material’s limited photoresponse region, loading a narrow bandgap material on WO3 is a generally known method for improving photo-harvesting. In this paper, we have synthesized WO3 films with different crystal facet ratios. After loading BiVO4 on these WO3 films, we measured the photoelectrochemical (PEC) performance to investigate the effects of WO3 facet choice on the heterojunction film electrode’s performance. We found that a high-intensity ratio of the (002) WO3 facet in X-ray diffraction (XRD) leads to a more negative onset potential and higher photocurrents in a lower potential region. The ultraviolet photoelectron spectra show a lower work function for the 002-dominant WO3 film compared to other WO3 films, which may result in a higher quasi-fermi level for the heterojunction electrode. Based on the XRD results, the high-intensity ratio of the (002) WO3 facet preferentially exposes the (020) BiVO4 facet, which may be a reason for the better charge extraction observed at low applied potential and high faradic efficiency on PEC water splitting. Together, this results in a high hole injection efficiency for 002-dominant WO3/BiVO4 films compared with WO3/BiVO4 films favoring other WO3 facet ratios.