• Proceedings of the Korean Nuclear Society Conference
• /
• 2003.10a
• /
• pp.367.2-367.2
• /
• 2003

• Proceedings of the Korean Nuclear Society Conference
• /
• 2003.10a
• /
• pp.446.2-446.2
• /
• 2003

• Nuclear Engineering and Technology
• /
• v.41 no.1
• /
• pp.11-20
• /
• 2009

Radiation effects on materials are inherently multiscale phenomena in view of the fact that various processes spanning a broad range of time and length scales are involved. A multiscale modeling approach to embrittlement of pressure vessel steels is presented here. The approach includes an investigation of the mechanisms of defect accumulation, microstructure evolution and the corresponding effects on mechanical properties. An understanding of these phenomena is required to predict the behavior of structural materials under irradiation. We used molecular dynamics (MD) simulations at an atomic scale to study the evolution of high-energy displacement cascade reactions. The MD simulations yield quantitative information on primary damage. Using a database of displacement cascades generated by the MD simulations, we can estimate the accumulation of defects over diffusional length and time scales by applying kinetic Monte Carlo simulations. The evolution of the local microstructure under irradiation is responsible for changes in the physical and mechanical properties of materials. Mechanical property changes in irradiated materials are modeled by dislocation dynamics simulations, which simulate a collective motion of dislocations that interact with the defects. In this paper, we present a multi scale modeling methodology that describes reactor pressure vessel embrittlement in a light water reactor environment.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.13 no.1
• /
• pp.237-252
• /
• 2000

Pressure sore is an area of ulceration and necrosis of the skin and underlying tissues usually occuring over the bony prominences of the body after prolonged or often repeated pressure. We reviewed and summarized the published articles and treatise on the treatment of pressure sore. The results were as follows : 1. Pressure sore occur due to prolonged or often repeated pressure. So it is better than decubitus ulcer that is called pressure sore. 2. The most common lesions of pressure sore are sacrum, ischial tuberosity, greater trochanter. 3. The cause of pressure sore are change of comprehension. urine, moisture, change of the ability of activity and exercise, shearing force. 4. The elements to influence on wound healing are collagen accumulation velocity, nutrition condition, Vitamine C, copper, iron. oxygen pressure, steroids, cell-toxic drug, radiation. 5. Non-operative treatments are managements of skin such as avoiding consistant pressure, dressing, preventing moisture, understanding patient and protecter, preventing spasm, improvement of systemic nutrition condition. 6. Operative treatements are debridement, suture, skin transplantation, muscle flap and musculaocutaneous flap surgery. Recently V-${\Gammer}$ advancement surgery in use of muscle and musculocutaneous flap is generally maded. 7. Complications of post-operation are wound rupture, infection, disappearance of transmitted skin, necrosis of flaps.

• The Journal of Korean Society for Radiation Therapy
• /
• v.33
• /
• pp.35-46
• /
• 2021

Purpose : By comparing and analyzing treatment plans using abdominal compression and The Continuous Positive Air Pressure(CPAP) during SABR of lung cancer, we try to contribute to the improvement of radiotherapy effect. Materials & Methods : In two of the lung SABR patients(A, B patient), we developed a SABR plan using abdominal compression device(the Body Pro-Lok, BPL) and CPAP and analyze the treatment plan through homogeneity, conformity and the parameters proposed in RTOG 0813. Furthermore, for each phase, the X, Y, and Z axis movements centered on PTV are analyzed in all 4D CTs and compared by obtaining the volume and average dose of PTV and OAR. Four cone beam computed tomography(CBCT) were used to measure the directions from the center of the PTV to the intrathoracic contacts in three directions out of 0°, 90°, 180° and 270°, and compare the differences from the average distance values in each direction. Result : Both treatment plans obtained using BPL and CPAP followed recommendations from RTOG, and there was no significant difference in homogeneity and conformity. The X-axis, Y-axis, and Z-axis movements centered on PTV in patient A were 0.49 cm, 0.37 cm, 1.66 cm with BPL and 0.16 cm, 0.12 cm, and 0.19 cm with CPAP, in patient B were 0.22 cm, 0.18 cm, 1.03 cm with BPL and 0.14 cm, 0.11 cm, and 0.4 cm with CPAP. In A patient, when using CPAP compared to BPL, ITV decreased by 46.27% and left lung volume increased by 41.94%, and average dose decreased by 52.81% in the heart. In B patient, volume increased by 106.89% in the left lung and 87.32% in the right lung, with an average dose decreased by 44.30% in the stomach. The maximum difference of A patient between the straight distance value and the mean distance value in each direction was 0.05 cm in the a-direction, 0.05 cm in the b-direction, and 0.41 cm in the c-direction. In B patient, there was a difference of 0.19 cm in the d-direction, 0.49 cm in the e-direction, and 0.06 cm in the f-direction. Conclusion : We confirm that increased lung volume with CPAP can reduce doses of OAR near the target more effectively than with BPL, and also contribute more effectively to restriction of tumor movement with respiration. It is considered that radiation therapy effects can be improved through the application of various sites of CPAP and the combination with CPAP and other treatment machines.

• Korean Journal of Head & Neck Oncology
• /
• v.16 no.1
• /
• pp.9-13
• /
• 2000

Objectives: To determine the tumor interstitial fluid pressure(TIFP) in patients with head and neck cancerand predict radiotherapy outcome.Materials and Methods: In 12 biopsy proven primary head and neck cancer patients with accessible by direct inspection and palpation, and of sufficient thickness(>1cm) to permit accurate needle placement, we measured TIFP at cervical lymph node before and during radiotherapy using a modified wick-in-needle technique. Tumor size was measured clinically and radiologically. Results: The mean preradiotherapy TIFP was 23.4mmHg. Preradiotherapy TIFP had significant relationship with tumor size(p=0.0009). Preradiotherapy TIFP was not different between complete response group and partial or less response group(p=0.114). Radiotherapy outcome was not different between group with above and group with below average TIFP(p=0.09). Conclusion: The mean TIFP was elevated with 23.4mmHg before radiation therapy. Preradiotherapy TIFP had significant relationship with tumor size. It is not definitive that TIFP could be prognostic indicator of radiation response.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.253.2-253.2
• /
• 2014

Micro hollow cathode discharges (MHCDs) are high-pressure, non-equilibrium discharges. Those MHCDs are useful to produce an excimer radiation. A major advantage of excimer sources is their high internal efficiency which may reach values up to 40% when operated under optimum conditions. To produce strong excimer radiation, the optimisation of the discharge conditions however needs a detailed knowledge of the properties of the discharge plasma itself. The electron density and temperature influence the excitation as well as plasma chemistry reactions and the gas temperature plays a major role as a significant energy loss process limiting efficiency of excimer radiation. Most of the recent spectroscopic investigations are focusing on the ultraviolet or vacuum ultraviolet range for direct detection of the excimer. In our experiments we have concentrated on investigating the micro hollow cathodes from the near UV to the near infrared (300~850 nm) to measure the basic plasma parameters using standard plasma diagnostic techniques such as stark broadening for electron density and the relative line intensity method for electron temperature. Finally, the neutral gas temperature was measured by means of the vibrational rotational structures of the second positive system of nitrogen.

• Journal of Advanced Navigation Technology
• /
• v.22 no.6
• /
• pp.585-590
• /
• 2018

GPS satellite orbits could be estimated precisely using GPS dynamics as well as GPS observations. Most of the perturbations are available to be generated using satellite position, velocity, well known model equations and coefficients. However, who wants to calculate solar radiation pressure (SRP) should choose a SRP model and estimate the coefficients of a SRP model. The accuracy of SRP model depends on the model characteristics. Therefore this paper has estimated coefficients of SRP models using CODE precise orbit product and compared the accuracy of orbit propagator depending on SRP model. The results show that the extended CODE orbit model (ECOM) and the reduced ECOM achieved cm level fitting orbit for the CODE 1-day orbit. Also orbit propagation model without SRP model consideration could get tens of meter orbits compared to CODE orbits.

• Journal of Nutrition and Health
• /
• v.46 no.2
• /
• pp.156-165
• /
• 2013

This study examined how achievement of session goals contributes to outcomes of subjects after participation in a 12-week lifestyle intervention program in men with metabolic syndrome (MetS). Thirty office workers with MetS, aged $47.2{\pm}6.6$ years, participated in this study, from March to July, 2011. The intervention program included face-to-face counseling five times during the 12-week period. Counselors and subjects designed session goals for each round. The average of the goal achievement rate was calculated based on compliance for each round. The subjects were divided into three groups according to their tertiles of achievement rate: Low-compliance group (LC, < 59%), medium-compliance group (MC, 59-70%), and high-compliance group (HC, > 70%). Anthropometry, biochemical index, and nutrient intake were examined at baseline and at the end of the 12-week intervention program. After the intervention, diastolic blood pressure (DBP) showed a significant decrease in the LC group, and waist circumference (WC) showed a significant decrease in the MC group. Systolic blood pressure (SBP), DBP, and low-density lipoprotein cholesterol (LDL) showed a significant decrease in the HI group. Changes in SBP and DBP were significantly lower in the HC group than in the MC group (p < 0.05, p < 0.01). Changes in LDL were significantly lower in the HC group than in the MC group (p < 0.05). Results for intake of total energy, protein, fat, and sodium, as well as rates of carbohydrate and fat intake, showed a significant decrease in all participants (p < 0.05). The change in fiber was significantly higher in the HC group than in the MC group (p < 0.05). The change of fruit serving size showed a significant increase in the HC group (p < 0.01). The number of risk factors for MetS showed a significant decrease in the LC and HC groups (p < 0.05), however, no significant mean differences were observed among the three groups. In conclusion, participation in this intervention program resulted in positive effects on risk factors for MetS, nutrient intake, and dietary habits, especially in the High-compliance group.

• The Journal of the Petrological Society of Korea
• /
• v.5 no.2
• /
• pp.129-134
• /
• 1996

Possibile phase transitions of graphite have been examined experimentally using piston cylinder and DAC with synchrotron radiation. The graphite-forming processes in high pressure and low temperature conditions and the phase change under super high pressure were studied in the conditions of 0.7 Gpa and 270-$360^{\circ}C$ in piston cylinder and under 39.6 Gpa in DAC. In the piston cylinder experiment using LiCO3as a catalyzer, we could synthesize disordered graphites whose TGD values change progressively form 9 to 53. It was known that the temperature of graphitization in 0.7 Gpa is between 270-$300^{\circ}C$. Numerous unknown XRD peaks were observed in the super high-pressure experiment. However, it is difficult to pick up a new peak of a hexagonal diamond phase. Application of the different high pressure apparatus as well as a peculiar X-ray source and various graphite specimen would be useful for super high-pressure experiment, and more detailed works are needed to characterize the unknown phase(s) observed in this study.