Ceramic materials have become essential due to their high durability, chemical stability, and excellent thermal stability in various advanced industries such as aerospace, automotive, and semiconductor. However, high-performance ceramic materials face limitations in commercialization due to the high cost of raw materials and complex manufacturing processes. Aluminum borate (Al₁₈B₄O₃₃) has emerged as a promising alternative due to its superior mechanical strength and thermal stability, despite its simple manufacturing process and low production cost. In this study, we propose a method for producing Al₁₈B₄O₃₃ spherical powder with increased uniformity and high flowability by controlling the particle size of B₂O₃. The content ratio of the manufactured Al18B4O33 spherical powder was Al2O3: B2O3 = 87:13, and it exhibited a 17% reduction in the Hausner ratio (1.04) and a 29% decrease in the angle of repose (23.9°) compared to pre-milling conditions, demonstrating excellent flowability.
As the demand for electric vehicles increases, the stability of batteries has become one of the most significant issues. The battery housing, which protects the battery from external stimuli such as vibration, shock, and heat, is the crucial element in resolving safety problems. Conventional metal battery housings are being converted into polymer composites due to their lightweight and improved corrosion resistance to moisture. The transition to polymer composites requires high mechanical strength, electrical insulation, and thermal stability. In this paper, we proposes a high-strength nanocomposite made by infiltrating epoxy into a 3D aligned h-BN structure. The developed 3D aligned h-BN/epoxy composite not only exhibits a high compressive strength (108 MPa) but also demonstrates excellent electrical insulation and thermal stability, with a stable electrical resistivity at 200 °C and a low thermal expansion coefficient (11.46×ppm/°C), respectively.
Inorganic-organic composites find extensive application in various fields, including electronic devices and light-emitting diodes. Notably, encapsulation technologies are employed to shield electronic devices (such as printed circuit boards and batteries) from stress and moisture exposure while maintaining electrical insulation. Polymer composites can be used as encapsulation materials because of their controllable mechanical and electrical properties. In this study, we propose a polymer composite that provides good electrical insulation and enhanced mechanical properties. This is achieved by using aluminum borate nanowhiskers (ABOw), which are fabricated using a facile synthesis method. The ABOw fillers are created via a hydrothermal method using aluminum chloride and boric acid. We confirm that the synthesis occurs in various morphologies based on the molar ratio. Specifically, nanowhiskers are synthesized at a molar ratio of 1:3 and used as fillers in the composite. The fabricated ABOw/epoxy composites exhibit a 48.5% enhancement in mechanical properties, similar to those of pure epoxy, while maintaining good electrical insulation.
In this paper, we developed a virtual reality-based contents that can gait analysis and gait training on a treadmill using a depth camera of Kinect. This content was used in the user's step length, step velocity, step count, flexion angle extracted by the Kinect skeleton tracking. Nine male subjects (24.9 years, 173.2cm) performed gait training using avatars to reflect their movements on the treadmill and confirmed result of gait analysis using real-time graphs to display their gait variables. Implemented contents can lead to a cognition reaction that is to avoid collisions with obstacles, as well as to determine the gait movements in a virtual reality. Based on these results, we will be able to make real time gait analysis and gait training, in consider the characteristics and safety of a rehabilitation patient by developing content that we have fun with additional tests for gait analysis.
Balhae(698~926) was the ancient state which opened the Nambuk-guk period with the Unified Silla. But Balhae architecture began to included in the history of Korean architecture only about 15 years ago, such as the books written by Yun Jang-seop or Ju Nam-cheol. I discussed four issues related to Balhae architecture in this paper. First, I criticized the excavation report of 24 stones remains at Jiangdong in Duhua city, and I asserted the ondol site belonged to different period. Second, I also interpreted that the building found on the tombs no.13 and no.14, in the Longhai burial area in Helong city must be a wooden stupa. Third, Balhae played some important roles in the history of ondol. It developed Koguryeo ondol in terms of structure, gave an opportunity to the ruling class to adopt ondol for the first time, and passed the heating system down to the Jurchen, the ancestor of the modern Manchurian. Fourth, the Russian-Korean joint research team excavated seven building sites in Koksharovka 1 fortress from Russian territory these four years, and it is reasonable to assume the fortress was the center of Anbyeon-bu, one of 15 local government districts in Balhae. I guess this buildings were the royal shrine built by resisters after the fall of Balhae, and the vessel stands found there must be used for ancestral memorial ceremony inside them.