• Journal of Korean Neurosurgical Society
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• v.47 no.5
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• pp.332-337
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• 2010

Objective : Although a transradial angiography is accepted as the gold standard for cardiovascular procedures, cerebral angiography has been performed via transfemoral approach in most institutions. The purpose of this study is to present our experience concerning the feasibility, efficacy, and safety of a transradial approach to cerebral angiography as an alternative to a transfemoral approach. Methods : Between February 2007 and October 2009, a total of 1,240 cerebral angiographies were performed via a transradial approach in a single center. The right radial approach was used as an initial access route. The procedure continued only after the ulnar artery was proven to provide satisfactory collateral perfusion according to two tests (a modified Allen's test and forearm angiography). Results : The procedural success rate was 94.8% with a mean duration of 28 minutes. All supra-aortic vessels were successfully catheterized with a success rate of 100%. The success rates of selective catheterization to the right vertebral artery, right internal carotid artery, left internal carotid artery, and left vertebral artery were 96.1%, 98.6%, 82.6% and 52.2%, respectively. The procedure was performed more than twice in 73 patients (5.9%), including up to 4 times in 2 patients. The radial artery occlusion was found in 4 patients (5.4%) on follow-up cerebral angiography, but no ischemic symptoms were observed in any of the cases. Conclusion : This study suggests that cerebral angiography using a transradial approach can be performed with minimal risk of morbidity. In particular, this procedure might be useful for follow-up angiographies and place less stress on patients.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.4
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• pp.482-505
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• 1993

The purpose of this study was to evaluate the fracture characteristics and the effect of resin bonding of laminate porcelain. In order to characterize the indentation-induced crack, Young's moduli and characteristic indentation dimensions were measured. The fatigue life under three point flexure test was measured using the electro-dynamic type fatigue machine, and the crack propagation with thermocycling was investigated on the condition of 15 second dwell time each in $5^{\circ}C\;and\;55^{\circ}C$ bath. The Vickers indentation pattern and the fracture surface were examined by an optical microscope and a scanning electron microscope (SEM). The results obtained were summarized as follows ; 1. Young's moduli(E) of the laminate porcelain and the resin cement used in this experiment were $62.56{\pm}3.79GPa$ and $15.01{\pm}0.12GPa$, respectively. 2. The initial crack size of the laminate porcelain was $69.19{\pm}5.94{\mu}m$ when an indentation load of 9.8N was applied, and the fracture toughness was $1.065{\pm}0.156MPa\;m^{1/2}$. 3. The fatigue life of laminate porcelain showed the constant fracture range at the stress level 27.46-35.30MPa. 4. When a cyclic flexure load was applied, the fatigue life of resin-bonded laminate porcelain was more decreased than that of laminate porcelain. 5. When a thermocycling was conducted, the crack growth rate of resin-bonded laminate porcelain was more increased than that of laminate porcelain. 6. Fracture surface showed the radial crack, the lateral crack, and the macroscopic crack branching region beneath the plastic deformation region when an indentation load of 9.8N was applied.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.137-146
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• 2007

The substitution of fossil fuels with biofuels has been proposed by the European Union (EU) as part of a strategy to mitigate greenhouse gas emissions from road transport, increase security of energy supply and support the development of rural communities. Vegetable oils and their derivatives (especially methyl esters), commonly referred to as 'biodiesel', are prominent candidates as alternative diesel fuels. They have advanced from being purely experimental fuels to the initial stages of commercialization. They are technically competitive with or offer technical advantages compared to conventional diesel fuel. However, several problems remain including economics, combustions, some emissions, lube oil contamination, and low-temperature properties. Therefore, quality control of fuel-related properties of biodiesel is needed to obtain consistent engine performance by fuel users. The quality of the fuel is affected by the oil composition. Rapeseed oil has been targeted for fuel use because it produces an oil with a close-to-optimum set of fuel characteristics. In this paper we have reviewed past and current efforts, both by traditional seed-breeding methods and by genetic engineering, to modify rapeseed oil quality and yield.

• Journal of Ocean Engineering and Technology
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• v.21 no.4
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• pp.34-37
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• 2007

The safety of ships is one of the most important concerns in terms of the environment and human life. A ship in bad condition is likely to be subject to accidents, such as collision and grounding. When a ship has minor collision damages in the form of circle or ellipse, its ultimate strength will be reduced. It is important to evaluate the reduction ratio of a ship's ultimate strength that results from damages. The strength reduction of a plate with a cutout in the form of hole has been treated by many researchers. A closed-form formula for the reduction of ultimate strength of a plate, considering the effect of several forms of cutout, has been suggested. However, the structure of ships is composed of plates and stiffeners so-called stiffened plates and it is likely that plates and stiffeners will be damaged together in collisions. This paper investigates the effect of minor collision damages on the ultimate strength of a stiffened plate by using numerical analysis. For this study, the deformed shape of minor collision damages on a stiffened plate was made by using a contact algorithm and was used as the initial shape for ultimate stress analysis. Then, a series of nonlinear FE analyses was conducted to investigate the reduction effects on the ultimate strength of the stiffened plate. The boundary conditions were simply supported at all boundaries, and the tripping of stiffener was neglected. The results are presented in the form of reduction ratio between the ultimate strength of an original, intact stiffened plate and that of a damaged stiffened plate.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2305-2311
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• 2002

The pressure tube is a major component of the CANDU reactor, which supports nuclear fuel bundle and heavy water coolant. Pressure tubes are installed horizontally inside the reactor and only selected samples are periodically examined during in-service inspection. In this respect, a probabilistic safety assessment method is more appropriate fur the assessment of overall pressure tube safety. The failure behavior of CANDU pressure tubes, however, is governed by delayed hydride cracking which is the major difference from pipings and reactor pressure vessels. Since the delayed hydride cracking has more widely distributed governing parameters, it is impossible to apply a general PFM methodology directly. In this paper, a PFM methodology for the safety assessment of CANDU pressure tubes is introduced by applying Monte Carlo simulation in determining failure probability Initial hydrogen concentration, flaw shape and depth, axial and radial crack growth rate and fracture toughness were considered as probabilistic variables. Parametric study has been done under the base of pressure tube dimension and hydride precipitation temperature in calculating failure probability. Unstable fracture and plastic collapse are used for the failure assessment. The estimated failure probability showed about three-order difference with changing dimensions of pressure tube.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.12
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• pp.1995-2001
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• 2001

In this study, a small punch creep(SP-Creep) test using miniaturized specimen(10${\times}$10${\times}$0.5mm) is described to develop the new creep test method for high temperature structural materials. The SP-Creep test is applied to 2.25Cr-lMo(STBA24) steel which is widely used as boiler tube material. The test temperatures applied for the creep deformation of miniaturized specimens are between 550∼600$^{\circ}C$. The SP-Creep curves depend definitely on applied load and creep temperature, and show the three stages of creep behavior like in conventional uniaxial tensile creep curves. The load exponent of miniaturized specimen decreases with increasing test temperature, and its behavior is similar to stress exponent behavior of uniaxial creep test. The creep activation energy obtained from the relationship between SP-Creep rate and test temperature decreases as the applied load increases. A predicting equation or SP-Creep rate for 2.25Cr-lMo steel is suggested. and a good agreement between experimental and calculated data has been found.

• Archives of Plastic Surgery
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• v.42 no.2
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• pp.218-222
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• 2015

Chronic expanding haematoma (CEH) is a rare type of haematoma that enlarges slowly and continuously without coagulation. It can occur following surgery because of shear stress-induced bleeding in the scar tissue between the subcutaneous fat and fascia. We present three cases of large chronic CEH that were successfully treated with triamcinolone injections. Three female patients developed large chronic CEH at 9 months, 5 years, and 6 years, respectively, after latissimus dorsi flap harvesting for breast reconstruction. Although the condition did not improve after multiple sessions of haematoma aspiration in the first two patients, it resolved following a single 40-mg triamcinolone injection along with appropriate compression dressing for several weeks. In the third patient, triamcinolone was injected immediately after the initial aspiration of the haematoma, and the condition improved considerably. There were no side effects in any of the patients. To the best of our knowledge, this is the first report of successful treatment of large CEH using triamcinolone. Therefore, we suggest that triamcinolone injections be considered for the treatment of CEH.

• Tunnel and Underground Space
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• v.16 no.1 s.60
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• pp.11-25
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• 2006

The world's largest nucleon decay experiment facility is constructed at a depth of approximately 1,000 meters, in the Kamio Mine, Japan. The excavated cavern is consisted of a cylinder of 42.4 m high and a semi elliptical dome of 15.2 m high, with a bottom diameter of 40 m. The total excavation volume is approximately $69,000\;m^3$. Because of the character as a large cavern excavation in deep underground, there is many unknown factors in rock mechanics. Based on the results of rock test and numerical analysis, the monitoring of rock mass behavior accompanying progress of construction was performed by various instruments installed in the rock mass surrounding the cavern. The monitoring data was used in the study of measures for cavern stability.

• Journal of Korean Society of Steel Construction
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• v.24 no.4
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• pp.361-369
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• 2012

In this study, prefabricated composite columns using high-strength angles (PSRC composite column) was studied. Concentric axial loading tests were performed for 2/3 scale PSRC specimens and an conventional SRC specimen with H-steel at the center of the cross-section. The test parameters were the steel ratio of angles and the spacing of lateral re-bars. The test results showed that by placing the angles at the corners of the cross-section for confinement with provided for the core concrete, the PSRC column specimens exhibited greater load-carrying capacity and deformation capacity than those of the conventional SRC column. The axial load-carrying capacity of the PSRC columns was greater than the prediction by KBC 2009. Using existing stress-strain relationship of confined concrete, the axial load-deformation relationship of the specimens were predicted. The numerical predictions correlated well with the test results in terms of initial stiffness, load-carrying capacity, and post-peak strength- and stiffness-degradations.

• Journal of Korean Society of Steel Construction
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• v.26 no.6
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• pp.581-594
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• 2014

In this paper, flexural resistance of hybrid girder under uniform bending moment was evaluated, which is composed of HSB800 and HSB600 steel for the flange and web, respectively. Doubly-symmetric and monosymmetric sections with noncompact or compact flange and slender, noncompact or compact web were considered. Nonlinear analyses with 3-dim. shell element model were performed to determine the 'flexural resistance of section' and the 'lateral torsional buckling strength' by taking initial imperfection and residual stress into account. The numerical results were compared with the AASHTO LRFD and Eurocode 3 specifications and also the applicability of AASHTO LRFD appendix A6 was examined for the sections with noncompact and compact web.