This study reports the synthesis and detailed characterization of Tb3+ doped sodium aluminum calcium borate (TbACNB) glasses, developed via melt-quenching, with the aim of establishing reliable luminescent calibration standards and X-ray imaging scintillators. A systematic investigation of photoluminescence, radioluminescence, proton-induced luminescence, and cathodoluminescence confirms a dominant and stable green emission centered at 546 nm, corresponding to the 5D4 -> 7F5 transition of Tb3+ ions. Among all tested concentrations, the 6 mol% Tb2O3 doped glass exhibits the highest photoluminescence quantum yield of 25.67 %, optimal decay lifetime, and consistent emission peak positions across all excitation methods, indicating structural and spectral stability. Proton and X-ray irradiation studies demonstrate linear dose response behavior and high spatial resolution up to 10 lp/mm, validating the glass applicability for high-resolution X-ray imaging. The glass retains uniform luminescence and color stability, with CIE coordinates at (0.31, 0.60), confirming its potential as a fluorescence calibration reference. The novelty of this work lies in demonstrating multi-stimulus luminescence consistency, dose dependent response, and X-ray imaging, positioning 6TbACNB as a dual purpose material for optical calibration and X-ray imaging systems.
Sr2Gd8(SiO4)6O2 oxyapatite materials doped with 1-50% Tb were successfully synthesized using the floating zone method, and the photoluminescence and scintillation properties were clarified. The samples exhibited emission at visible wavelength and decay time in the milli second range, originating from the 4f-4f transitions of Tb3+ under ultraviolet light and X-ray irradiation. The photoluminescence quantum yields showed two local maximum values of approximately 70% as a function of Tb concentration. In the pulse height spectra under 137Cs gamma-rays irradiation, the 5% Tb-doped Sr2Gd8(SiO4)6O2 had the light yield of 14600 photons/MeV which was the highest value among the present samples.
Human–robot co-carrying tasks reveal their potential in both industrial and everyday applications by leveraging the strengths of both parties. Effective control of robots in these tasks requires managing the energy level in the closed-loop systems to prevent potential dangers while also minimizing motion errors to complete the shared tasks. The collaborative tasks pose numerous challenges due to varied human intentions in adapting to workspace characteristics, leading to human–robot conflicts. In this paper, we develop a cooperation control framework for human–robot co-carrying tasks constructed by utilizing reference generator and low-level controller to aim to achieve safe interaction and synchronized human–robot movement. Firstly, the human motion predictions are corrected in the event of prediction errors based on the conflicts measured by the interaction forces through admittance control, thereby mitigating conflict levels. Low-level controller using an energy-compensation passive velocity field control approach allows encoding the corrected motion to produce control torques for the robot. In this manner, the closed-loop robotic system is passive when the energy level exceeds the predetermined threshold, and otherwise. Furthermore, the proposed control approach ensures that the system’s kinetic energy is compensated within a finite time interval. The passivity, stability, convergence rate of energy, and power flow regulation are analyzed from theoretical viewpoints. Human-in-the-loop experiments involving 18 participants have demonstrated that the proposed method significantly enhances task performance and reduces human workload, as evidenced by both objective metrics and subjective evaluations, with improvements confirmed by statistical tests (p < 0.05) relative to baseline methods.
Autonomous personal mobility vehicle (APMV) is an innovative small autonomous transportation device designed for individual use in mixed-traffic environments, such as shared spaces and indoor environments. To enhance the interaction experience between pedestrians and APMVs and to prevent potential risks, it is crucial to investigate pedestrians’ walking behaviors when interacting with APMVs and to understand the psychological processes underlying these behaviors. This study aims to investigate the causal relations between subjective evaluations of pedestrians and their walking behaviors during interactions with an APMV equipped with an external human-machine interface (eHMI). An experiment of pedestrian-APMV interaction was conducted with 42 pedestrian participants, in which various eHMIs on the APMV were designed to induce participants to experience different levels of subjective evaluations and generate the corresponding walking behaviors. Based on the hypothesized model of the pedestrian’s cognition-decision-behavior process, the results of causal discovery align with the previously proposed model. Furthermore, this study further analyzes the direct and total causal effects of each factor and investigates the causal processes affecting several important factors in the field of human-vehicle interaction, such as situation awareness, trust in vehicle, risk perception, hesitation in decision making, and walking behaviors.
Mg alloy Mg85Zn6Y9 has attracted attention because of its superior mechanical properties. These properties come from the unique Zn6Y8 cluster of the dopants Zn and Y atoms. Recently, Mg99.2Zn0.2Y0.6, which has lower concentrations of Y and Zn, exhibits similar superior mechanical properties to Mg85Zn6Y9, but it is difficult to form the perfect Zn6Y8 cluster because of low concentration. To investigate the cluster structure of Mg99.2Zn0.2Y0.6, we carried out photoelectron holography. From the hologram of Y 3d, we successfully obtained the atomic positions of Zn atoms, and the atomic positions are different from the perfect Zn6Y8 cluster.
