• Journal of Chest Surgery
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• v.41 no.6
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• pp.751-754
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• 2008

Angiosarcoma is the most common primary intracardiac malignancy, but many published papers have reported it to be rather rare. The prognosis of angiosarcoma is known to be very poor, and the treatment of choice has been surgery until recently, but many centers currently tend to try multi modal therapies, including chemotherapy and radiotherapy. In this report, we present a rare case in which an intracardiac angiosarcoma could have threatened the patient's life in short time by the rapid progression of the tumor, which caused right atrial rupture.

• Journal of Biosystems Engineering
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• v.31 no.4 s.117
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• pp.369-375
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• 2006

Mechanical properties of potato and sweet potato were measured under impact and compression loading. The test apparatus consisted of disgital storage oscilloscope and simple mechanisms which can apply compression and impact forces to potatoes and sweet potatoes. The mechanical properties could be measured while the tissues were ruptured in a very short period time less than 10 ms by impact loading. Rupture force, energy, and deformation were measured as mechanical properties of potatoes and sweet potatoes under impact and compression loading. Rupture forces under impact and compression loading were in the range of 84.1 to 93.7N and 128.9 to 132.2N for external tissues and 60.1 to 64.8N and 158.9 to 171.1N for internal tissues of potato and sweet potato, respectively. Compression speeds and drop heights for each test were in the range of 1.25 to 62.5mm/min and 8 to 24cm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.11
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• pp.951-956
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• 2008

The high temperature creep properties of the generating plant's high temperature tube, pipe and header and such are very significant in accordance with long-time exposure to the high temperature and pressure environment. Not only this, but as the welding procedure is compulsory for the cohesion of components, the creep properties regarding the local microstructures of steel weldment are very important. In order to understand the creep properties regarding the local microstructures of steel weldment, the SP-Creep test which is easy to get sample from the field component was conducted. The local microstructure of steel weldment, that is, W.M. and B.M.'s microstructures were observed using the SEM. The rupture time of W.M. was longer as 110 % averagely in a same condition, which is the consequence of the difference of the microstructure. Each lethargy coefficient of B.M. and W.M. is evaluated by the relation among the temperature, load and the rupture time from SP-Creep Test. The life estimation equation can be induced by the transformation of Power-law. B.M. and W.M. for each $550\;^{\circ}C$ and $575\;^{\circ}C$, the very similar to normal temperature of the domestic thermal power generation in working, are estimated.

• Nuclear Engineering and Technology
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• v.47 no.3
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• pp.351-361
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• 2015

External reactor vessel cooling (ERVC) for in-vessel retention (IVR) has been considered one of the most useful strategies to mitigate severe accidents. However, reliability of this common idea is weakened because many studies were focused on critical heat flux whereas there were diverse uncertainties in structural behaviors as well as thermal-hydraulic phenomena. In the present study, several key factors related to molten corium behaviors and thermal characteristics were examined under multi-layered corium formation conditions. Thereafter, systematic finite element analyses and subsequent damage evaluation with varying parameters were performed on a representative reactor pressure vessel (RPV) to figure out the possibility of high temperature induced failures. From the sensitivity analyses, it was proven that the reactor cavity should be flooded up to the top of the metal layer at least for successful accomplishment of the IVR-ERVC strategy. The thermal flux due to corium formation and the relocation time were also identified as crucial parameters. Moreover, three-layered corium formation conditions led to higher maximum von Mises stress values and consequently shorter creep rupture times as well as higher damage factors of the RPV than those obtained from two-layered conditions.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.3998-4002
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• 2012

With continuing progress of nanotechnologies and various applications of nanoparticles, one needs to develop a quick and fairly standard assessment tool to evaluate cytotoxicity of nanoparticles. However, much cytotoxicity studies on the interpretation of the interaction between nanoparticles and cells are non-mechanistic and time-consuming. Here, we propose a simple screening method for the analysis of the interaction between several AgNPs (5.3 to 64 nm) and fluorescence-dye containing vesicles ($12{\mu}m$) acting as a biomimetic cell-membrane. Fluorescence-dye containing vesicle was prepared using a fluorescence probe (1,6-diphenyl-1,3,5-hexatryene), which was intercalated into the lipid bilayer due to their hydrophobicity. Zeta potential of all materials except for bare-AgNPs (+32.8 mV) was negative (-26 to -54 mV). The morphological change (i.e., rupture and fusion of vesicle, and release of dye) after mixing of the vesicle and AgNPs was observed by fluorescence microscopy, and fluorescence image were different with coating materials and surface charge of x-AgNPs. In the results, we found that the surface charge of nanoparticles is the key factor for vesicle rupture and fusion. This proposed method might be useful for analyzing the cytotoxicity of nanoparticles with cell-membranes instead of in vitro or in vivo cytotoxicity tests.

• Korean Journal of Materials Research
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• v.21 no.11
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• pp.596-603
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• 2011

The very high temperature gas reactor (VHTR) is one of the next generation nuclear reactors for its safety, long-term stability, and proliferation-resistance. The high operating temperature of over 800$^{\circ}C$ enables various applications with high energy efficiency. Heat is transferred from the primary helium loop to the secondary helium loop through the intermediate heat exchanger (IHX). The IHX material requires creep resistance, oxidation resistance, and corrosion resistance in a helium environment at high operating temperatures. A Ni-based superalloy such as Alloy 617 is considered as a primary candidate material for the intermediate heat exchanger. In this study, the microstructures of Alloy 617 crept in pure helium and air environments at 950$^{\circ}C$ were observed. The rupture time in helium was shorter than that in air under small applied stresses. As the exposure time increased, the thickness of outer oxide layer of the specimens clearly increased but delaminated after a long creep time. The depth of the carbide-depleted zone was rather high in the specimens under high applied stress. The reason was elucidated by the comparison between the ruptured region and grip region of the samples. It is considered that decarburization caused by minor gas impurities in a helium environment caused the reduction in creep rupture time.

• Journal of Korean Foot and Ankle Society
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• v.18 no.3
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• pp.115-118
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• 2014

Purpose: The purpose of this study is to report on the result of repairing Achilles tendon using absorbable suture under nerve block. Materials and Methods: We retrospectively reviewed 20 patients with acute Achilles tendon rupture who were followed up for at least six months after the operation. We repaired Achilles tendon using two absorbable sutures using the Krackow technique for the proximal stump and the Kessler technique for the distal stump. A programmed postoperative management including non-weight bearing with a short leg cast for four weeks after the operation was applied for all patients. We evaluated clinical results using American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, visual analogue scale (VAS) for satisfaction, range of motion of ankle, functional recovery rate, and the starting time of single heel raise. Results: The mean VAS score for satisfaction and AOFAS score was 9.2 and 93.0, respectively. The affected ankle showed a mean dorsiflexion rate of 90% and plantar-flexion rate of 94% compared to the uninjured side. The single heel raise could start at a mean of 3.5 months after the operation. Conclusion: Treatment of Achilles tendon rupture with absorbable suture material using the hybrid suture technique of proximal Krackow and distal Kessler showed sufficient stability and minimal chronic inflammatory reaction.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.905-910
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• 2003

In this paper, we develop real-time monitoring system to detect third-party damage on natural gas pipeline by using sound propagation model. Since many third-party incidents cause damage that does not lead to immediate rupture but can grow with time, the developed real-time monitoring system can execute a significant role in reducing many third-party damage incidents. The developed system is composed of three steps as follows: i) DSP based system, ii) wireless communication system, iii) the calculation and monitoring software to detect the position of third-party damage using the propagation speed of acoustic wave. Furthermore, the developed system was set at practical offshore pipeline between two islands in Korea and it has been operating in real time.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.404-410
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• 2009

This study was carried out to develop a self-propelled type explosive subsoiler for improving the root zone soil conditions in orchard and other forest fields. Prototype was designed to be able to inject air and other soil improving material such as lime into soil at the same time, and thus improve the air permeability and drainage of orchard soils to promote the root growth of tree for high quality fruit production. Soil penetration device of explosive subsoiler is composed of air hammer, penetration rob and air injection nozzle. To support the soil penetration device of explosive subsoiler to penetrate vertically, modified Scott-Russel mechanism was used. Timing control device for simultaneous injection of soil improving material with air was attached to the out side wall of air cylinder and as the cylinder move, the soil improving material was injected into soil at the same time. Turning radius of prototype was 2.2-2.3 m with good mobility in sloped land. It took approximately 1 minute for lime injection system to reach the optimum pressure of 9.9 kg/$cm^2$, average 10-20 seconds were required to rupture soil with the depth of 50 cm and 2-3 seconds were required for explosion, so all in all about 1 minute and 20 seconds were required for one cycle of explosion. Maximum soil rupture depth and diameter were 50 cm and 3-4 m respectively depending on the soil type and soil moisture content. For final design of explosive subsoiler inclination angle of lime hopper was increased from 60 degree to 70 degree and the shape of hopper was changed from rectangular cone to circular cone to solve the clogging problem of lime at out let. Agitating system operated by compressed air was attached to the metering device of the prototype, thus more than 90 cc of lime was discharged per cycle from metering device without clogging problems.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.103-111
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• 2002

Steady-state creep analysis of power generation turbine blade is carried out considering thermal loads and centrifugal forces. Creep strains and stresses of the turbine blade are calculated for 3-D finite clement model of the turbine blade. From the numerical results, creep life of the turbine blade is predicted. The results of creep analysis during about 200 hours indicate that creep strains of the turbine blade do not reach the rupture strain of GTD111. Creep stresses of the turbine blade are relaxed as time increases. Maximum creep strain occurs at the tip section of the airfoil pressure surface. The maximum creep strain of the turbine blade is expected close to the rupture strain after 50,000 hours approximately. The turbine blade may not have creep damage for the starting procedure of the turbine.