We conducted a study on excessive doping of the Cr and In elements in Bi-Sb-Te materials satisfying the Hume- Rothery rule, and investigated the resulting electrical and thermal properties. From X-ray diffraction (XRD) results, we confirmed the formation of a single phase even with excessive doping. Through analysis of electrical properties, we observed the highest enhancement in electrical characteristics at y = 0.2, suggesting that the appropriate ratio of Bi-Sb significantly influences this enhancement. Using the Callaway-von Baeyer (CvB) model to assess scattering due to point defects, we calculated the experimental point defect scattering factor (ΓCvB.exp), which was notably high due to the substantial differences in volume and atomic weight between the substituted (Cr, In) and original (Bi, Sb) elements. Additionally, we conducted a single parabolic band (SPB) modeling analysis of materials with compositions y = 0.1 and 0.2, where, despite a decrease in densityof- states effective mass (md *) during the enhancement process from y = 0.1 to 0.2, a sharp increase in non-degenerate mobility (μ0) led to an 88 % increase in weighted mobility (μw). Furthermore, analyzing zT with respect to nH revealed a 51 % increase in zT at a composition of y = 0.2. This study confirmed a significant reduction in lattice thermal conductivity with the co-doping strategy, and with further compositional studies to improve electrical properties, we anticipate achieving high zT.
The brown planthopper (BPH) and white-backed planthopper (WBPH), significant rice pests, cannot overwinter in Korea and primarily originate and migrate from Southeast Asia and China, where they cause considerable damage. These planthoppers, along with other pests, annually migrate to the Korean Peninsula. Monitoring their migration is essential for controlling their populations and maintaining agricultural productivity. Traditional monitoring methods often struggle with timeliness due to time and manpower constraints. To address this, we developed the Smart Aerial Net Traps (SANT) for immediate tracking of pests. The SANT system is installed in 43 locations across the country and has been used for over 10 years to track migrating insects. Our research shows that SANT is a more effective method for monitoring migratory pests compared to traditional methods. SANT enables real-time tracking of various migratory pests and can also be utilized in different areas, such as analyzing pest population changes and determining pest origins through the study of air currents.
Post-disturbance recovery pattern of subtidal soft corals-macroalgae mixed community and the role of water depth were investigated. The experiment was conducted in a subtidal rock wall of Munseom, Jeju Island, Korea for 2.5 years. Artificial disturbance was done at established treatment plots at depths of 10, 15 and 20 m and were then compared with undisturbed control plots. After disturbance, recovery of soft corals was very slow, whereas macroalgae quickly occupied the plots and reached a similar level as the control in 6 months, and this pattern was consistent at all water depths. This unbalanced speed of recovery caused higher macroalgae establishment than soft corals in treatment compared to control plots, indicating a possible phase shift in the community structure. This study provides an important implication for the necessity of monitoring the influence of disturbance at a larger scale, from a conservation perspective of soft corals in Jeju coast.