Nan Kai University of Technology

ABSTRACTThe aim of this paper is to propose a novel adaptive observer‐based stabilizer for a class of uncertain nonlinear time‐delay systems subject to unmatched external disturbances. A terminal sliding mode controller based on an adaptive super‐twisting terminal sliding mode observer is developed by using the linear matrix inequality (LMI) technique. Under the proposed scheme, the closed‐loop system converges to origin in finite time as the matching condition is satisfied and converges to the uniform ultimate bound in the effects of unmatched external disturbances. The design of the observer and the stabilizer does not require the upper bound of uncertainties and external disturbances. The chattering phenomenon is eliminated. The observer and the stabilizer can be efficiently designed from the solutions of LMIs. Simulation results illustrate the effectiveness of the proposed control scheme.

This study describes a new species of earthworms belonging to the genus Amynthas (Clitellata: Megascolecidae) from northern Taiwan. It is named Amynthas popi sp. nov. It is a large earthworm with four pairs of spermathecal pores in 5/6-8/9. It has a postsetal papilla medial to each male porophore and papillae closely or widely paired in presetal VIII, widely paired in postsetal XIX, and occasionally more closely paired in presetal XIX. Its compact prostate glands together with short, stout and horizontal prostatic ducts are rarely seen among the native Amynthas earthworms known from Taiwan. Amynthas sheni (Chen, 1935) is a false synonym of Amynthas corticis (Kinberg, 1867) as the former has postsetal papillae on ventrum of VIII and occasionally also on IX, four pairs of esophageal hearts in X-XIII, well-developed prostate glands in XVI-XXI and long, U-curved prostatic ducts, which clearly set it apart from the latter. Other taxonomic issues relating to A. corticis are discussed. Additionally, Amynthas jampeanus fumigatus (Michaelsen, 1899) should be regarded as a subspecies of Amynthas bonthainensis (Benham, 1896) since it bears a very close resemblance to A. bonthainensis than to Amynthas jampeanus (Benham, 1896). The following combination is proposed: Amynthas bonthainensis fumigatus (Michaelsen, 1899) comb. nov.

Abstract As the application of power electronic components in renewable and green energy technologies continues to increase, there is an increasing trend in the utilization of higher voltage and frequency levels. This shift may result in more frequent partial discharge (PD) phenomena that can accelerate the degradation of insulation materials and shorten the lifespan of the components. Therefore, it is critical to ensure the reliability and durability of these components. This study investigated the effects of voltage magnitude and frequency on the PD and insulation degradation of printed circuit board (PCB) samples. Five different test samples were fabricated using a PCB as the substrate and an epoxy resin as the insulating coating. Two distinct testing configurations were employed: one for assessments based on a commercial frequency (60 Hz) and the other for assessments based on a high frequency (600 Hz). This study examined the behavior of PD within PCBs and the resulting insulation deterioration. The results demonstrated that all the samples exhibited significantly lower PD inception voltages (PDIV) at high frequencies compared with those at the commercial frequency. Specifically, the maximum decrease in the PDIV observed was 5 kV, while the minimum reduction was 3.3 kV. These findings highlight the critical impact of frequency on the PD behavior and underscore the importance of understanding these effects to enhance the reliability of electronic components in high-frequency applications.

All-inorganic perovskites have emerged as promising candidates for tandem and photovoltaic applications due to their wide bandgap and enhanced stability.

Two new freshwater gobies of Rhinogobius were discovered from Taiwan. They are fluvial species belonging to R. rubromaculatus complex. The new species, Rhinogobius baborinisanensis n. sp. which is collected from northern Taiwan can be well distinguished from all other congeners by the unique combination of the following features: (1) fins: second dorsal fin rays modally I/8; anal fin rays I/7; pectoral fin rays modally 17; (2) squamation: longitudinal scale series 32-34 (modally 33); perdorsal scales usually 13-14; scale series from origin of first dorsal fin to upper pectoral fin origin modally 10; (3) vertebral count 27; (4) rear edge of mouth merely extending to or slightly beyond vertical of anterior margin of pupil in male and (5) its own specific colouration. Another new species, Rhinogobius macromaculatus n. sp. which is collected from southern Taiwan can be well distinguished from all other congeners by the unique combination of the following features: (1) fins: second dorsal fin rays modally I/8; anal fin rays I/7; pectoral fin rays modally 15; (2) squamation: longitudinal scale series 27-28 (modally 28); perdorsal scales usually 14-15; scale series from origin of first dorsal fin to upper pectoral fin origin modally 8; (3) vertebral count 27; (4) rear edge of mouth extending slightly beyond vertical of anterior margin of pupil in male and (5) its own specific colouration. The brief comparison and discussion of morphological differentiation from congeners would be also addressed.

A power distribution system occasionally requires uninterrupted load transfer to avoid affecting the quality of power consumption, but the differences in voltage amplitudes and phases of both feeders may cause short-duration high currents. The critical issue of possible solutions is the different phase angles. This paper proposes the joint application of an energy storage system (ESS) and a proportional–integral controller to compensate for the active and reactive power in one feeder while using the voltage of the other feeder as the target value. The compensated power is injected into the transfer feeder buses to regulate the voltage amplitude and phase angles, thereby alleviating short-duration high currents during the load transfer of feeders. In this study, MATLAB/Simulink was used for circuit simulation analysis, and an 11.4 kV feeder model for three-phase power distribution systems, as well as an energy storage device, was constructed. Finally, the simulation results are analyzed to examine the improvement of transfer current under different feeder load scenarios.

VR has shown positive growth in the world in recent years, which is mainly due to projects such as learning, games, entertainment and experiential activities. VR has changed the way of life of users, providing users with more interesting interactions and immersive experiences. This study aims to investigate students’ practical capabilities and learning effectiveness under the instruction strategy of integrating virtual reality into simulation games into the Vehicle Body Electrical System Comprehensive Maintenance and Repair Services Practice curriculum for students of the Dept. of Auto Mechanics in a skills-based senior high school. Two student classes of the Dept. of Auto Mechanics major in Electrical Engineering featuring practical subjects in one skills-based senior high school in central Taiwan were chosen as the participants for this study. By way of pretest–post-test research design and heterogeneous grouping, an 8-week instruction experiment was conducted in which ZPD (zone of proximal development) instruction strategies were used in the experimental group (with 43 persons), while traditional didactic instruction strategies were used in the control group (with 36 persons). ZPD instructional strategies analyze and collect quantitative and qualitative data to investigate the instructional effectiveness and feasibility in developing ZPD as the research material in the practical curriculum for the study area of the Power Machinery in Vehicle Body Electrical System Comprehensive Maintenance and Repair Services practice. According to the research objective, the results are concluded as follows. (1) Students achieved the best learning effectiveness when adopting ZPD (zone of proximal development) strategies in which virtual reality was integrated into the vehicle charging and starting system to investigate students’ automotive diagnostic troubleshooting and fault-clearing capabilities. (2) Students attained the highest acceptance in learning phenomenon when adopting ZPD (zone of proximal development) strategies in which virtual reality was integrated into students’ familiar practice factory environment and the tools and equipment operation process. (3) Students had a higher acceptance of learning effectiveness when using virtual reality simulation games in the disassembly and functional detection of vehicle charging and starting systems. (4) There is a positive effect when integrating virtual reality simulation games into ZPD instruction strategies in the knowledge, skills and attitude on students’ overall inquiry practical capabilities and their learning effectiveness.

Abstract In this study, we conducted a theoretical analysis of thermal stress around an arbitrarily shaped hole in a thermoelectric material under electric current density and energy flux loading. Based on complex variable methods, conformal mapping, and analytical continuation theorem, the exact solutions of the thermal stress around a hole were obtained for the Seebeck coefficient and electric and heat conductivity. Based on the conversion efficiency equation of thermoelectric materials, higher electrical conductivity and lower heat conductivity should be selected to achieve an optimal design. The theoretical results indicated that higher electrical conductivity could reduce the thermal stress around the hole. However, energy flux and thermal stress concentration might be generated around the adiabatic hole due to the presence of a matrix with lower heat conductivity. Hence, thermoelectric materials with lower thermal conductivity should be selected carefully to avoid premature failure around the hole caused by thermal stress concentration. Finally, we also obtained and discussed the stress intensity factors of a hypocycloid-type crack.