Graphite crystals consist of a layered structure with stacked graphene sheets, and exhibit self-lubricating properties due to the facile sliding of graphene layers in the horizontal direction, facilitated by weak Van der Waals bonds along the c-axis. When this graphite material is impregnated with a lubricating liquid, it forms a solid and stable lubricating layer, and effectively reduces damage to the counter material from friction-induced wear under conditions of high-load reciprocating motion. This study investigates how oxidation-induced pore expansion and the silane treatment of graphite affect lubricating oil impregnation behavior, the friction coefficient of impregnated graphite, frictional stability, and microstructural changes at the friction surface. It was found that graphite oxidation within the chemical reaction temperature range enhanced porosity and increased the rate of lubricating oil impregnation. The functionalization of the graphite surface with hydrophobic silane coupling agents also significantly enhanced oil uptake, with a pronounced observed improvement when utilizing hydrophobic oils. Under a vertical load of 360 kgf and a surface pressure of 3 MPa, the graphite surface treated with hydrophobic silane and impregnated with oil exhibited the lowest average friction coefficient of 0.192 over 600 cycles. During the friction and wear process, a lubricating layer formed on the graphite surface, which contributes to stable wear performance. This surface modification strategy offers high applicability in industries such as automotive, aerospace, and heavy machinery, with the potential to significantly enhance component performance and extend service life under high-load, low-speed reciprocating conditions.
The purpose of this study is to observe the effect of elasticity of taping on ankle muscles’activity and endurance after plyometric training that easily causes ankle injury, and provide baseline data for physical therapy intervention methods. The study subjects are 24 male students in their 20s who attend N University in Choongnam. They were divided into three groups; 8 subjects in the elastic taping group, 8 in the non-elastic taping group, and 8 in the non-taping group(control group). They had plyometric training for 6 weeks. After the training, this study measured their maximum voluntary isometric contraction(MVIC) and muscle endurance of the muscles around ankle joint. The experiment result is as follows. After the training, all three groups showed improvement in muscle strength and endurance. The elastic taping group showed insignificant improvement in muscle strength but significant increase in muscle endurance in plantarflexion. In dorsiflexion, both muscle strength and endurance increased significantly. The non-elastic taping group showed insignificant improvement in muscle strength but significant increase in muscle endurance in plantarflexion. Taping during plyometric training had a little or insignificant effect on muscle endurance and strength compared to the non-taping group.
Jung Sook Sung, Jung Bong Kim, Hyun Nye Yoon, Jong Wook Jeong, Jong Hyun Park, Hyung-Jin Baek, Jeong Hoon Lee, Chun Geon Park, Man Kyu Huh, Gyu Taek Cho
A 40-year-old G1 P0 L0 A1 woman was referred to our clinic with 6-year history of infertility. Before visiting the clinic, she had 3 cycles of In-Vitro Fertilization (IVF) procedures (2 cycles of Controlled Ovarian Stimulation-IVF and 1 cycle of frozen-thawed Embryo Transfer (ET)) at other clinic. She had medical history of abortion at early gestation following FET (frozen-thawed-ET). The patient had complete type of septate uterus, double cervix and longitudinal vaginal septum. Vaginal septotomy was done first and 1 month later, hysteroscopic septoplasty was followed using ballooning filled with dye. After septoplasty, we inserted ballooning and left for several days to compress septal endometrium on the septectomy area. All procedures were done in the ambulatory operating room without laparoscopy or admission. 3 months later, she had in vitro fertilization-embryo transfer (IVF-ET) and FET procedures in our clinic. She had successful pregnancy and now is at 22 weeks of gestation. New ambulatory septoplasty using dye-filled ballooning is easy, safe and minimally invasive surgery for treatment of complete septate uterus.