1,838 research outputs found
Suppression of adiabatic shear band formation by martensitic transformation of retained austenite during split Hopkinson pressure bar test for a high-strength bainitic steel
No full textIn this study, a high-strength bainitic steel was fabricated and austempered at 350 ?C for 15 min, 90 min, and 24 h to control the volume fraction of retained austenite (RA) while keeping an appropriate hardness level. Their dynamic compressive properties were investigated in relation to the ASB formation and cracking by the SHPB. The specimen austempered for 90 min showed the highest volume fraction of RA along with the highest compressive properties. This specimen also possessed the high resistance to form a transformation-ASB (tASB), which was attributed to the active deformation-induced martensitic transformation of RA. Since the applied dynamic energy was consumed by the martensitic transformation as well as the ASB formation, the active transformation effectively delayed the critical strain for initiating formation. Therefore, this critical strain concept, which was well correlated with dynamic compressive properties, would be an important key factor for suppressing the ASB formation and for improving the ballistic performance.11Nsciescopu
sj-docx-1-npx-10.1177_1934578X231191857 - Supplemental material for Two New Meroterpenoid Derivatives From <i>Sargassum macrocarpum</i> With Their Anti-Oxidant Activities
No full textSupplemental material, sj-docx-1-npx-10.1177_1934578X231191857 for Two New Meroterpenoid Derivatives
From Sargassum macrocarpum With
Their Anti-Oxidant Activities by Ji-Yul Kim, Dae-Cheol Choi, Jeong Min Lee, Hyun-Soo Kim, Dae-Won Ki, Seok-Chun Ko, Mi-Jin Yim, Gun-Woo Oh, Kyung Woo Kim, Chul Hwan Kim, Kyung Lee, Kyunghwa Baek and Dae-Sung Lee in Natural Product Communications</p
supplementay_file – Supplemental material for Survival benefit of first-generation epidermal growth factor receptor–tyrosine kinase inhibitors in female with advanced lung cancer
No full textSupplemental material, supplementay_file for Survival benefit of first-generation epidermal growth factor receptor–tyrosine kinase inhibitors in female with advanced lung cancer by Byoung Soo Kwon, Ji Hyun Park, Seulgi Kim, Sojung Park, Wonjun Ji, Woo Sung Kim, Jae Cheol Lee, Yu Rang Park and Chang-Min Choi in Tumori Journal</p
Role of retained austenite on adiabatic shear band formation during high strain rate loading in high-strength bainitic steels
No full textAdiabatic shear band (ASB) is a well-known structure formed during high strain-rate deformation in various metallic materials, and significantly affects dynamic properties as well as ballistic performance. Retained austenite contained in recently developed high-strength martensitic or bainitic armor steels usually triggers a TRansformation-Induced Plasticity (TRIP), which enhances a strain hardening capability. However, this TRIP effect on ASB formation has hardly been investigated yet. In this study, a laboratory-scale split Hopkinson pressure bar was utilized to describe the ASB formation behavior in four high-strength martensitic or bainitic armor steels. Their formation possibilities were then correlated with hardness, strength, and dynamic compressive properties coupled with the TRIP. This TRIP occurring under adequate austenite stability improved the strain hardening, sufficiently absorbed the dynamically applied energy, and effectively suppressed the ASB formation. These behaviors suggest the favorable utilization of retained austenite in high-strength armor steels for wide-range ballistic applications.11Nsciescopu
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FX Law and Regulations in Korea ::Problems and Prospects /
No full textIn FX Law and Regulations in Korea: Problems and Prospects , Min-woo Kang offers a comprehensive and thorough discussion of the FX regulatory system in Korea, with a special focus on its chronic problems and possible remedies under the overhauled legal system. The author has provided technical analysis on each provision of the complex Korean law, which is commonly accepted as too convoluted, even for legal professionals. Fully utilising a host of legal materials as well as documents in the relevant economic theory, Min-woo Kang convincingly provides the rationale for FX regulation and a robust argument for amending the current Korean law in a significant way. This piece sheds a light on the path Korean lawmakers and regulatory authorities will take. Academics and practitioners interested in the Korean FX law will find this a good reference
Scalar Adaptive Kalman Filtering for Stellar Inertial Attitude Determination
No full textThis paper describes attitude determination algorithm for the low earth orbit(LEO) spacecraft using stellar inertial sensors. The cascaded gym/star tracker extended Kalman filter is constructed to fuse two sensor data. And then the smoothing of the measurement are proposed for an unreasonable jump of star tracker. The smoothing algorithm for the rejection of star tracker error jumps is designed by scalar adaptive filter. The proposed algorithms operate to process the measurement of gyro/star tracker Kalmari filter, therefore, it is comparatively simple to apply these methods to other integration systems. Simulations to gym/star tracker integrated system show that the proposed method is effective
Effects of pentoxifylline and tocopherol on an osteoradionecrosis animal model
No full textPurpose: Osteoradionecrosis (ORN) is known to be a refractory disease in the oral and maxillofacial field. The purpose of this study was to examine the effects of pentoxifylline (PTX) and tocopherol (TP) on an ORN animal model focused on bone healing. Materials and methods: A total of 48 Sprague-Dawley rats were used: 40 received a single irradiation dose of 35 Gy on the left mandible, and eight were used as the nonirradiated control group. The rats received PTX (T1, C1), TP (T2, C2), a combination of PTX and TP (T3, C3), or normal saline (T4, C4). Three weeks after irradiation, the mandibular posterior teeth were extracted. The rats were sacrificed 4 weeks after extraction. Results: In the T3 group, bone volume/tissue volume was 19.62 +/- 16.03 (%), bone mineral density was as 0.31 +/- 0.16 (g/cm(3)) in the micro-CT analysis, which were higher than that of other groups (p = 0.025, p = 0.012, respectively). In the histological analysis, bone regeneration was the most prominent in the T3 group. The ratio of empty lacunae was the highest in the T4 group, 68.77 +/- 15.47 (%, p = 0.004). Immunohistochemistry showed that the expression of TNF-alpha was relatively lower in the T3 than in the T4 or T2 groups. The RT-qPCR showed the expression level of PECAM, VEGF-A, and osteocalcin was more than twofold as high as in the T3 group compared to the other groups. Conclusion: The combination of PTX and TP appears to promote angiogenesis and osteogenesis in a rat ORN model. Therefore, PTX and TP might be useful in the treatment and prevention of ORN.N
Bio-inspired incorporation of functionalized graphene oxide into carbon nanotube fibers for their efficient mechanical reinforcement
No full textAn efficient strategy for the enhancement of mechanical properties of carbon nanotube (CNT) fibers is developed using functionalized graphene oxide with a quaternary ammonium (QA) group (QA-FGO). QA-FGO is designed to induce the p-cation interaction, one of the strongest interactions in living systems, with CNT fibers. Based on the strategy, the tensile strength (58 MPa), specific strength (0.49 N/tex), modulus (2.5 GPa) and toughness (1.1 MJ/m(3)) of CNT fibers are enhanced to 409 MPa, 0.65 N/tex, 13.4 GPa, and 10.1 MJ/m(3), respectively. The reinforcement mechanism is systematically demonstrated with experimental and theoretical approaches.
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