• Archives of Reconstructive Microsurgery
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• v.24 no.1
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• pp.28-31
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• 2015

A case report of a patient who developed radiation-induced sarcoma in the left chest wall is presented. The patient had partial mastectomy and adjuvant radiation therapy (total dose, 5,220 cGy) and chemotherapy. Five years later, she visited with rapidly growing mass with central ulceration in the irradiated chest wall. The mass was diagnosed as malignant fibrous histiocytoma. The chest wall mass resected en bloc ($23{\times}18cm$) including five consecutive ribs. After the defected thoracic cage was reinforced using a polytetrafluoroethylene patch, omental flap and split thickness skin graft was done for soft tissue coverage. We applied negative pressure wound closer system for effective suction of omeantal exudate. The wound healed without complications. The patient suffered no perioperative pulmonary complications. Pulmonary function tests showed no significant changes. Each of Gore-Tex, omental flap, negative pressure wound therapy and skin graft is widely used method. However, If these methods are used in combination, we can reconstruct the large defect of chest wall including multiple ribs without any repiratory function problems.

• Atmosphere
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• v.22 no.4
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• pp.449-454
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• 2012

This study presents the long-term variability of spring precipitation over the Korean peninsula. It is found that the significant interdecadal change in the spring precipitation has occurred around year 1991. Over the Korean peninsula the precipitation for the post-1991 period increased by about 30 mm per year in CMAP and station-measured data compared to the precipitation prior to year 1991. Due to an increased baroclinicity during the later period, the low-level negative pressure anomaly has developed with its center over northern Japan. Korea is situated at the western end of the negative pressure anomaly, receiving moisture from westerly winds and producing more precipitation. Also, we estimate the change in the near future (years 2020~2040) spring precipitation using six best performing Coupled Model Intercomparison Project 3 (CMIP3) models. These best model ensemble mean shows that spring precipitation is anticipated to increase by about 4% due to the strengthened westerlies accompanied by the northwestern enhancement of the North Pacific subtropical high.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.119-125
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• 2017

In this paper, the characteristics and load carrying capacity of square pocket surfaces on a slider bearing are discussed for the thin film effect by the square pocket slider bearing. To study the lubrication, a Reynolds equation is used in this paper for the analysis of the slider bearing characteristics with square pocket surfaces. For numerical analysis, the central differencing scheme finite difference method is used. In a slider bearing with square pocket surfaces, the simulation dependent parameters such as pressure and load carrying capacity of the bearing can be acquired from the independent parameters, the slope of the slider bearing and number of pockets on the upper slider. These results can be acquired by the programmed softwar,e and they can be analyzed and stored in a sequential data file for later analysis. Furthermore, their pressure and load capacity distribution can be displayed easily by using the developed program with the Matlab GUI.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.3
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• pp.31-40
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• 2020

The structure and dynamics of multiple shock waves are studied numerically using a finite volume solver for a model with nozzle exit Mach number of 1.75. At first, the shock variation based on images were analyzed using a Matlab program then later to the wall static pressure variation. The amplitude and frequency variation for multiple shock waves are analyzed. The cross-correlation between the shock location suggests that the first and the second shocks are well correlated while the other shocks show a phase lag in the oscillation characteristics. The rms values of pressure fluctuations are maximum at the shock locations while the other parts in the flow exhibit a lower value os standard deviation.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2960-2973
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• 2022

Since Fukushima nuclear power plant (NPP) accident in 2011, the importance of research on various severe accident phenomena has been emphasized. Particularly, detailed analysis of combustion risk is necessary following the containment damage caused by combustion in the Fukushima accident. Many studies have been conducted to evaluate the risk of local hydrogen concentration increases and flame propagation using computational code. In particular, the potential for combustion by local hydrogen concentration in specific areas within the containment has been emphasized. In this study, the process of flame propagation generated inside a reactor core to containment during a loss of coolant accident (LOCA) was analyzed using MELCOR 2.1 code. Later in the LOCA scenario, it was expected that hydrogen combustion occurred inside the reactor core owing to oxygen inflow through the cold leg break area. The main driving force of the oxygen intrusion is the elevated containment pressure due to the molten corium-concrete interaction. The thermal and mechanical loads caused by the flame threaten the integrity of the containment. Additionally, the containment spray system effectiveness in this situation was evaluated because changes in pressure gradient and concentrations of flammable gases greatly affect the overall behavior of ignition and subsequent containment integrity.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.33.1-33.1
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• 2020

Ram pressure stripping (RPS) which is known to be one of the key effects that can remove the interstellar gas in the dense environment, can be described as a simple momentum transfer relation (Gunn & Gott 1972). However, it has been suggested that the actual gas stripping process is likely more complicated than Gunn & Gott's prescription due to the complexity of gas physics such as compression, cooling and heating. By comparing the gas truncation radius predicted by theory with the stripping radius measured from the HI observation of Virgo cluster galaxies, we attempt to verify how well the RPS process can be understood by momentum transfer alone. Among the sample of galaxies undergoing active RPS, we generally find a good agreement between what is predicted and what is observed within the measurement uncertainties. However, those galaxies with the signs of other environmental effects than RPS such as tidal interaction, and/or the ones likely at relatively early or later stages of RPS show some offsets between the theory and the observation. These results imply that Gunn & Gott's formula works reasonably well in a broad sense when the RPS is a dominant process and the surrounding environment at the current location of the sample can be well defined. Otherwise, the impact of the second mechanism, as well as the (current and past) environment of the sample, should be more carefully reviewed to assess the impact of RPS on galaxy evolution.

• Journal of the Korea Concrete Institute
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• v.18 no.2 s.92
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• pp.213-218
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• 2006

Meniscus, adsorbed layer thickness, capillary pressure and disjoining pressure was deduced in extended meniscus region in cement paste pore by hydrostatic equilibrium. From the results, the relationship between pore size and adsorbed layer thickness could be derived and adsorbed layer thickness represents $0.299{\sim}2.700nm$ according to pore size $1nm{\sim}1{\mu}m$. Especially, disjoining pressure rapidly Increased in less than 10 nm pore size according to adsorbed layer thickness. Therefore, it is interpreted that autogenous shrinkage of cement paste is highly increases in formation of less than 10 nm pore size. Predictions of autogenous shrinkage in cement paste considering driving force for autogenous shrinkage with capillary pressure and disjoining pressure was low in comparison with experiment values between $1{\sim}4$ days and high in later period. These tendency could be thought that pore damage by mercury injection in early age makes shrinkage driving force underestimate and assumption for unsaturated independent pore makes overestimate. These interactions might be needed corrections considering on hydration or pore replacement model.

• Archives of Plastic Surgery
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• v.33 no.5
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• pp.669-671
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• 2006

Purpose: Congenital insensitivity to pain with anhidrosis(CIPA) is a rare form of autosomal recessive peripheral sensory neuropathy. Patients with CIPA show loss of pain sensation, which leads to corneal ulcers and opacities, self-mutilation of the tongue and fingertips, as well as fractures with subsequent joint deformities and chronic osteomyelitis. The purpose of this report is to highlight the fact that pressure sores also are a potential complication of CIPA. Methods: This case report describes a patient presenting with pressure sores resulting from CIPA. A 5-year-old boy was referred to our department for the treatment of a $5{\times}5cm$ sacral pressure sore as a result of a hip spica cast applied for the treatment of a left hip joint dislocation. He had a history suggesting CIPA such as multiple bony fractures, mental retardation, recurrent hyperpyrexia, anhidrosis, and clubbing fingers due to oral mutilation. A microscopic examination of the sural nerve showed mainly large myelinated fibers, a few small myelinated fibers and an almost complete loss of unmyelinated fibers. After wound preparation for two weeks, the exposed bone was covered with two local advancement flaps. Results: Two weeks later, complete wound healing was achieved. A 16-month follow-up showed no recurrence. However, the patient presented with a new pressure sore on the left knee due to orthosis for the treatment of the left hip joint dislocation. Conclusion: The early diagnosis of CIPA and special care of pressure sores are important for preventing and treating pressure sores resulting from CIPA.

• The Journal of Engineering Geology
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• v.11 no.1
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• pp.1-11
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• 2001

The geological characteristics of Korea are that we can encounter the rock layer only after 10m of excavation, methods to presume the rock pressure distribution of the rock layer is urgently needed. When using the existing empiric science of Terzaghi-Peck, Tschebotarioff to measure the rock pressure of the rock layer, underestimate the real strength because of the cohesion is ignored. Therefore calculating the horizontal sliding force of wedge block, which includes the dips and shear strength of discontinuities and surcharge load etc., think to be to getting a closer rock stress of the real rock pressure acting upon the earth structure in rock mass. This research use Coulomb soil pressure theory assuming that the backfill soil will yield wedge failure when it has cohesion, applying Prakash-Saran(l963), and then it uses equilibrium of force and shear strength $\tau$=c+$\sigma$tan $\Phi$ of the cliscontinuities. Analyzing shear strength and dips of cliscontinuities using calculated theory according to the status of discontinuities aperture, we were able to find out that because the cohesion and friction angle of the rock layer itself is large enough, how the dip directions and dips facing the excavation face is the only factor deciding whether or not the rock stress is applied. The evaluated theory of this research should be strictly estimated, so that the many parameters such as c, $\Phi$value, types and structures of rock class, excessive lateral pressure, dynamic load, earthquake, needed later when calculating shear strength of discontinuities and especially the ground water effect acting on rock layer should be coumpted with many measuring data achieve at the insite to study the application.

• The Journal of the Acoustical Society of Korea
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• v.22 no.1E
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• pp.11-18
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• 2003

Non-singular boundary element method (BEM) codes are developed in acoustics application. The BEM code is then used to calculate unknown boundary surface normal displacements and surface pressures from known exterior near field pressures. And then the calculated surface normal displacements and surface pressures are again applied to the BEM in forward in order to calculate reconstructed field pressures. The initial exterior near field pressures are very well agreed with the later reconstructed field pressures. Only the same number of boundary surface nodes (1178) are used for the initial exterior pressures which are at first calculated by Finite Element Method (FEM) and BEM. Pseudo-inverse technique is, used for the calculation of the unknown boundary surface normal displacements. The structural object is a tuning fork with 128.4 ㎐ resonant. The boundary element is a quadratic hexahedral element (eight nodes per element).