Optimization of Ca–Al–Mn–Si Substitution Level for Enhanced Magnetic Properties of M-Type Sr-Hexaferrites for Permanent Magnet Application

Enhanced hard magnetic properties were achieved in M-type hexaferrite by optimizing the substitution levels of Mn, Al, and Si for Fe, and Ca for Sr within SrFe12O19. The addition of Al–Si–Mn effectively controlled crystallite growth, resulting in an increased coercivity (HC), while causing a decrease in the remanent magnetization (4πMr). A higher Ca content exhibited a trend of increasing the sintered density but decreasing the 4πMr and HC. The optimized composition, considering both the 4πMr and HC, was determined to be Sr0.8Ca0.2Fe10.2Mn0.1Al0.2Si0.1O19−d, with a sintered density of 4.84 g/cm3, 4πMr = 2.22 kG, and HC = 5.10 kOe. This result demonstrates the achievement of isotropic magnets with controlled crystal growth and densification without additional sintering additives. This development is promising, as this enhancement could be achieved without the use of cobalt, an expensive but essential ingredient in high-performance permanent magnets

Estimation of the Appropriate Output of Diesel Generator for Microgrid System in Chuja Island

This paper proposes a method to estimate the appropriate minimum output of diesel generator in the microgrid system that composed of renewable energy, diesel generator and energy storage systems. While maximizing the output of the renewable energy in the microgrid, to maintain the power system stability is very important. To analyze the effectiveness of the proposed method, simulation is carried out by using the PSCAD/EMTDC program with past weather and power load data in Chuja Island located in the south area of Korean peninsula, respectively. In the simulation result, power quality of Chuja Island power system under variable renewable energy generation is stable. The proposed method is useful for operating the isolated microgrid system

Estimation of the Appropriate Output of Diesel Generator for Microgrid System in Chuja Island

This paper proposes a method to estimate the appropriate minimum output of diesel generator in the microgrid system that composed of renewable energy, diesel generator and energy storage systems. While maximizing the output of the renewable energy in the microgrid, to maintain the power system stability is very important. To analyze the effectiveness of the proposed method, simulation is carried out by using the PSCAD/EMTDC program with past weather and power load data in Chuja Island located in the south area of Korean peninsula, respectively. In the simulation result, power quality of Chuja Island power system under variable renewable energy generation is stable. The proposed method is useful for operating the isolated microgrid system

Impact of Cold Stress on Physiological Responses and Fruit Quality of Shiranuhi Mandarin in Response to Cold Conditions

We identified the minimum temperature limits to ensure Shiranuhi mandarin growth and fruit quality and provided overwintering temperature management guidelines. Expanded polystyrene panels with air conditioners were exposed to −1, −3, and −5 °C in the greenhouse for 15 h to determine the overwintering temperature. Leaves and fruits were analyzed at intervals for physiological response, fruit quality, and aromatic components. The low temperature treatment groups showed 1.3 to 1.4 times increased malondialdehyde content in leaves and 1.1 to 1.3-fold higher electrolyte linkage rates in the −5 °C treatment group alone. The sugar/acidity ratio was 1.1 to 1.3 times higher in the −5 °C treatment than in the control due to rapid acid reduction. The fruit firmness and citrus color index decreased notably after 21–28 days of treatment. Ascorbic acid content significantly decreased 17.3%–41.1% at −5 °C. Among the aromatic compounds, decanal levels notably increased with −5 °C treatment; −5 °C cold treatment notably affected oxidative stress in leaves and the sugar/acid ratio, ascorbic acid content, and aromatic compounds in fruits. If prolonged exposure to temperatures 0 °C during fruit growth and >−3 °C after harvest as the minimum temperature to preserve fruit set and quality

Anticancer Effect of Mountain Ginseng on Human Breast Cancer: Comparison with Farm-Cultivated Ginseng

Mountain ginseng has been used generally as a pharmacopuncture for cancer therapy in clinical practice in Northeast Asia. Nonetheless, there have been few scientific reports for the anticancer action of mountain ginseng. In this study, we investigated whether mountain ginseng extract (MGE) could inhibit the growth of breast cancer in in vitro and in vivo models. MGE showed stronger cytotoxicity than farm-cultivated ginseng extract (FGE) through promoting ROS generation. Also MGE dose-dependently brought about mitochondrial dysfunction in MCF-7 cells. In addition, MGE induced apoptosis through enhancing the activities of caspase-3/7 by regulation of expression of Bcl-2, Bax, cytochrome c, and cleaved caspase-3 in the MCF-7 cells. Consistent with the in vitro results, MGE significantly reduced tumor weights compared with FGE in mice transplanted with MCF-7 cells, and it regulated the expression of apoptosis-related proteins, such as Bcl-2, Bax, cytochrome c, cleaved caspase-3, and cleaved PARP, in the tumor tissues. Additionally, MGE included higher total ginsenoside contents than FGE. In conclusion, MGE, which is richer in ginsenosides, exerts a stronger anticancer action than FGE in breast cancer. The anticancer action of MGE may be closely correlated with caspase-mediated apoptosis through upregulating ROS generation. Therefore, these findings may be helpful for a clinical understanding of the anticancer mechanism of MGE for breast cancer patients