• Composites Research
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• v.25 no.1
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• pp.9-13
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• 2012

In this research, biomechanical characteristics of the bone tissue are experimentally investigated. By using specimens of the bovine bone, the mechanical properties are obtained through tension and shear tests. In experiments, non-homogeneous and anisotropic properties with respect to longitudinal and transversal directions are observed. Moreover, the viscoelastic behavior in which modulus and strength properties are dependent on strain rates is analyzed. It is expected that a numerical damage model of the bone be efficiently established based on the results.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.109-109
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• 1999

Recently, low energy ion beam irradiation has been adopted for surface modification. Low energy ion beam irradiation has many advantages in polymer engineering such as weak damage, good adhesion, noticeably-enhanced wettability(less than 15 degree), good reproducibility and so on. In this experiment, chemical reactions between free radicals and environment gas species have been investigated using angle-resolved XPS and TRIM code. In the case of low ion beam energy (around 1 keV), energy loss in polymer is mainly originated from atomic collisions instead of electronic interference. Atomic collisions could generated displaced atoms and free radicals. Cold cathode-ion source equipped with 5cm convex grid was used in an O2 environment. Base and working pressure were 5$\times$10-6 and 2.3$\times$10-4 Torr. Flow rates of argon and oxygen were fixed at 1.2 and 8 sccm. target materials are polyethylene polyvinyidenefluoride and polytetrafluoroethylene.

• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.301-308
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• 1999

The present study investigates numerically particle laden flow through compressor cascades and a rocket nozzle. Engines are affected by various particles which are suspending in the atmosphere. Especially in the case of aircraft aviating in volcanic, industrial and desert region including many particles, each components of engine system are damaged severely. That damage modes are erosion of compressor blading and rotor path components, partial or total blockage of cooling passage and engine control system degradation. Numerical prediction and experimental data, erosion rates are predicted for two materials - ceramic, soft metal - on compressor blade surface. Aluminum oxide ($Al_2O_3$) Particles included in solid rocket propelant make ablative the rocket motor nozzle and imped the expansion processes of propulsion. By the definition of particle deposition efficiency, characteristics of particles impaction are considered quantitatively Stoke number is defined over the various particle sizes and particle trajectories are treated by Lagrangian approach. Particle stability is considered by definition of Weber number in rocket nozzle and particle breakup and evaporation is simulated in a rocket nozzle.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.90-93
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• 2000

In this study, the rise throughput and the stability in fabrication of device can be obtained by applying of CMP process to STI structure in 0.18um semiconductor device. To employ in STI CMP, the reverse moat process has been added thus the process became complex and the defects were seriously increased. Removal rates of each thin films in STI CMP was not equal hence the devices must to be effected, that is, the damage was occured in the device dimension in the case of excessive CMP process and the nitride film was remained on the device dimension in the case of insufficient CMP process than these defects affect the device characteristics. To resolve these problems, the development of slurry for CMP with high removal rate and high selectivity between each thin films was studied then it can be prevent the reasons of many defects by reasons of many defects by simplification of process that directly apply CMP process to STI structure without the reverse moat pattern process.

• The Journal of Internal Korean Medicine
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• v.24 no.2
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• pp.387-394
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• 2003

Amiodarone is an effective antiarrhythmic agent because of its vasodilator actions. Nowadays it is mostly used to treat patients with severe cardiomyopathy or coronary artery disease complicated by disturbances in the supraventricular or ventricular rhythm. But, some doctors are reluctant to prescribe it because of its many side effects. These include impairment of liver and thyroid fuction and, rarely, damage to the lungs. Most of all, its most serious side effect is amiodarone-induced pulmonary toxicity, which can occur in up to 10% of patients, with mortality rates as high as 50%. We recently experienced one case of the patient with the Amiodarone-induced pulmonary toxicity. The clinical manifestations of the patient was cough, painful breathing, fever, presence of rales, decreased breath sounds, and sputum. We report the change of the patient's symptoms through both western medical treatment and oriental medical treatment.

• Nuclear Engineering and Technology
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• v.47 no.7
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• pp.895-906
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• 2015

Background: Mitigation of primary water stress corrosion cracking (PWSCC) is a significant issue in the nuclear industry. Advanced nickel-based alloys with lower susceptibility have been adopted, although they do not seem to be entirely immune from PWSCC during normal operation. With regard to structural integrity assessments of the relevant components, an accurate evaluation of crack growth rate (CGR) is important. Methods: For the present study, the extended finite element method was adopted from among diverse meshless methods because of its advantages in arbitrary crack analysis. A user-subroutine based on the strain rate damage model was developed and incorporated into the crack growth evaluation. Results: The proposed method was verified by using the well-known Alloy 600 material with a reference CGR curve. The analyzed CGR curve of the alternative Alloy 690 material was then newly estimated by applying the proven method over a practical range of stress intensity factors. Conclusion: Reliable CGR curves were obtained without complex environmental facilities or a high degree of experimental effort. The proposed method may be used to assess the PWSCC resistance of nuclear components subjected to high residual stresses such as those resulting from dissimilar metal welding parts.

• The Journal of Korean Physical Therapy
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• v.31 no.4
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• pp.161-168
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• 2019

Most athletes with anterior cruciate ligament (ACL) ruptures undergo a surgical ACL reconstruction (ACLR) and rehabilitation. On the other hand, controversy still exists because neither a reconstruction nor rehabilitation have been proven to be superior in the management of ACL injury. This study reviewed the success rates of interventions to provide recommendations for the optimal management after an ACL injury. One of the most important considerations after an ACL injury is the timing and type of intervention. At the early stages, which involve the loss of volume and strength of quadriceps femoral muscle, weight bearing (closed kinetic chain) exercises with pain management followed by high velocity resistance exercises in an open kinetic chain environment are recommended to improve the quadriceps function. After that, it is important to apply intensive isokinetic exercise with a lower extension rate. In this case, it is important to apply overload to the muscles and to simultaneously lead the co-contraction of the hamstrings. Standards are essential because the timing and type of interventions are crucial to prevent re-injury and complications, such as osteoarthritis, as well as to confirm the successful outcome of the treatment. Different interventions recommended for ACL damage have yet to reach consensus. Further studies will be needed to observe the effects of the intervention through multidisciplinary approaches.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.239-246
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• 2021

The immunological sperm separation method is economical compared to the existing sorting method, and it is promising for the development of new technologies by reducing sperm damage. Wholemom (WM) is a sex-regulating protein that comprises on immunoglobulin G coupled with magnetic nanoparticles (MNPs) that responds to surface proteins derived from the Y chromosome in cattle. Y sperms are restricted in motility as the WM aggregates them, and the magnet could separate the non-aggregated cells. This study was conducted to investigate the effect of WM treatment on the characteristics of bull sperm. After treating sperm with WM and incubation for 6 h, the motility parameters including total motility, progressive motility, velocity average path, velocity straight line, amplitude of lateral head displacement, and linearity were significantly higher in the WM treatment group than in the control group (p < 0.05). Sperm viability and acrosome reaction rates were similar in both groups during each incubation period (p > 0.05). In conclusion, the immunological sperm sexing procedure using a monoclonal antibody conjugated with MNPs did not affect the characteristics of bull sperm. This study suggests that compared to other techniques, the immunological method for sperm sexing could classify sperm quickly and efficiently without the use of expensive equipment.

• Corrosion Science and Technology
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• v.21 no.1
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• pp.68-76
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• 2022

Several technologies are employed to protect substrates from corrosion and erosion damage. In particular, arc thermal spray coating technology is widely used as anti-corrosive technology for steel and concrete structures and is applied to offshore plants and petrochemical and drilling facilities. In this investigation, solid particle impingement erosion experiments were performed on an arc thermal spraying-coated specimen using 85% Al-14% Zn-1% Zr wire rod in KR-RA steel. This study investigated the effect of fluorosilicone sealing on the erosion resistance characteristics of the thermal spray coating layer. The erosion rates of the thermal spray-coated and sealed specimens were 4.1×10^-4 and 8.5×10^-4, respectively. At the beginning of the experiment, the fluorosilicone sealant was almost destroyed by the impact of the solid particles. The destruction time for the coating layer was 10 minutes for the thermal spray-coated specimen and 13 minutes for the sealed specimens, indicating that the sealed specimens had better erosion resistance characteristics to solid particle impingement.

• Corrosion Science and Technology
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• v.21 no.5
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• pp.327-339
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• 2022

The water-jet technique started by Bridgman can cut metal and alloys without harmful gas and fume. However, while this technique is convenient to cut metals and alloys, in the case of coated pipe, water jet induces the degradation of coatings on the pipes, and may facilitate structural failure, leakage, and loss of products. While there are many reports on the effect of water jet on cut metals and the damage of metallic materials, research on the effect of water impingement on the epoxy coatings has been little studied. In this work, we therefore control the velocity of water jet, distance between nozzle and specimen, and water temperature, and discuss the effect of water impingement on the epoxy coatings. Increasing water velocity and water temperature and reducing nozzle distance increased the degradation rates of three epoxy coatings were increased. Among three test parameters - water velocity, nozzle distance and water temperature, water temperature was relatively effective to increase the degradation rate of epoxy coatings.