• Journal of the Korean earth science society
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• v.32 no.1
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• pp.1-11
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• 2011

The impact echo and impulse response methods were applied to the safety inspection of concrete structure, which has the rear cavity. The concrete structure model used in this study was divided into four sections, pure concrete, concrete+cavity, reinforced concrete with iron bar, and reinforced concrete+cavity, respectively. Previous study performed by authors have showed a possibility of success to use these method for detection of the rear cavity of concrete structure. Therefore, we tried to get more enhanced result with IE and IR methods through this study. Especially, IE and IR methods are relatively accurate to map the point of measurement, which makes it possible to interpret the depth of the concrete bed and effect by rear cavity with confidence. Followings were revealed from the results; the IE method shows some small peak zones probably indicating the rear cavity in the frequency lower than the resonance frequency and the changes of mobility and dynamic stiffness in the IR method indicate the weak zones. The proposed methods can be used to delineate the weak zones of the concrete structure.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.235-240
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• 2017

The purpose of this study is to confirm the safety of the clinical application of image co - registration in steteotactic radiosurgery by evaluating the 3D positioning of magnetic resonance imaging using image co-registration. We performed a retrospective study using three-dimensional coordinate measurement of 32 patients who underwent stereotactic radiosurgery and performed magnetic resonance imaging follow-up using image co-registration. The 3 dimensional coordinate errors were $1.0443{\pm}0.5724mm$ (0.10 ~ 1.89) in anterior commissure and $1.0348{\pm}0.5473mm$ (0.36 ~ 2.24) in posterior commissure. The mean error of MR1 (3.0 T) was lower than that of MR2 (1.5 T). It is necessary to minimize the error of magnetic resonance imaging in the treatment planning using the image co - registration technique and to confirm it.

• Journal of Yeungnam Medical Science
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• v.15 no.2
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• pp.297-305
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• 1998

Recently, several alternatives have been attempted in the management of benign prostatic hyperplasia (BPH) to reduce morbidity of traditional transurethral resection of the prostate (TURP). Among new modalities, transurethral electrovaporization (TEVP) is considered as a promising alternative. To evaluate the safety and initial efficacy of JEVP using the roller loop electrode (ProSurg Inc. USA) on BPH patients, we compared the results of TEVP with those of TURP and visual laser ablation of the prostate (VLAP). In this study, a total of 115 patients with symptomatic BPH were underwent TEVP (n=17), TURP (n=59) or VLAP (n=39) since 1995. Before treatment, patients were evaluated with an International Prostate Symptom Score (IPSS) and the measurement of maximal uroflow rate (MFR) and postvoid residual urine (PVR). After treatment, the operative and hospital records were reviewed. The uroflowmetry and IPSS were re-evaluated 3-10 months after treatment. In clinical outcome of re-evaluation compared to the preoperative parameters, there was a clinically significant improvement in three procedures. TEVP resulted in 62% reduction in IPSS (TURP, 73% : VLAP, 69%), 84% improvement in MFR (TURP, 113% : VLAP, 91%), and 74% reduction in PVR (TURP, 88% : VLAP, 78%). TEVP had shorter duration of hospitalization and catheterization than the others. TEVP was associated with lower rates of treatment-related complication than TURP. In conclusions, TEVP is considered as a useful procedure to treat symptomatic BPH. And, the advantages of TEVP over TURP include excellent intraoperative hemostasis, lower morbidity, shorter hospital stay and simple technique. In addition the advantages over VLAP include lower cost, shorter duration of catheterization and early symptom improvement.

• Journal of the Korean Geophysical Society
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• v.5 no.2
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• pp.143-151
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• 2002

Bulku temple in the city of Kyungju, Korea, built in 791 and reconstructed in the 20th century, is the home of seven national treasures including two three-story stone pagodas, Dabotap (height 10.4m, width 7.4m, weight 123.2ton) and Seokgatap (height 10.8m, width 4.4m, weight 82.3 ton). An earlier archaeological investigation shows that stone pagodas have experienced severe weathering process which will threaten their stability. At the base part of Dabotap, an offset of the stone alignment is also observed. For the purpose of the structural safety diagnosis of two pagodas, we introduce the nondestructive geophysical methods. Site characteristics around the pagodas are determined by the measurement of multiple properties such as seismic velocity, resistivity, image of GPR(ground-penetrating radar). Near the pagodas, the occurrence of high resistivity (up to 2200 Ωm) is obvious whereas their outskirts have as low as 200 Ωm. For the velocity of the P wave, the site of Dabotap has the range of 500~800 m/s which is higher than counterpart of Seokgatap with the velocity of 300~500m/s, indicating the solider stability of Dabotap site. Consequently, in addition to GPR images, the foundation boundaries beneath each stone pagodas are revealed. The Dabotap site is in the form of an octagon having 6-m-long side with the depth of ~4m, whereas the Seokgatap site the 9m × 10m rectangle with the depth of 3m. These subsurface structures appear to reflect the original foundations constructed against the stone load of ~8 ton/㎡. At the subsurface beneath the northeast of each pagoda, low seismic velocity as well as low resistivity is prominent. It is interpreted to represent the weak underground condition.

• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.2
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• pp.49-54
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• 2017

Purpose The high-dose administration of I-131 has been standing for the basic therapy method of thyroid cancer. In korea, it is not necessary for patients to be hospitalized if the administration dose are under 1.2 GBq. However, if the dose are over 1.2 GBq, the patients should be stay in special ward with radiation shield. In such cases, the radioactivity level upon release should be under a dose of $70{\mu}Sv/hr$ at a distance of approx. 1m. This regulation bring the patients to stay for about 2 to 3 days in ward before the release. Materials and Methods Using the inpatients' release data of severance hospital, an inpatient-days were retrospectively calculated and compared with practical data and estimate the inpatient-days with the conditions of korea ($70{\mu}Sv/hr$), Japan ($30{\mu}Sv/hr$), germany ($3.5{\mu}Sv/hr$ at a distance of approx. 2 m), and other european countries. Results When a effective half-life of 15.4 was used, the expected inpatient-days were calculated as 2.15 days in the condition of Japanese regulation and 1.37 days in the condition of korean regulation. The practical inpatient-days of patients in Severance hospital were 1.32 days. Conclusion As ICRP 94 has been mentioned that the release of patients administrated with I-131 for the therapy should be carefully considered because each patients has different thyroid uptake rate and their conditions with family members after the release from the ward. Nonetheless, efforts to bring more aquate data which is for getting closer to the practical data should be continuously studied.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.2
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• pp.189-197
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• 1994

Analytic methods for Cr(VI) level in industrial hygienic field were suggested by the National Institute for Occupational Safety and Health(NIOSH method 7600, 7604). There were growing needs for measurement of Cr(III) and Cr(VI) levels simultaneously. Two analytical methods were suggested to determine Cr(III) and Cr(VI) levels simultaneously. The one is method by using reversed phase high peformance liquid chromatography(HPLC) and the other is by using ion exchange HPLC. The purpose of this work was to evaluate the usefulness of these two analytic methods. For the difference of ionic charges of Cr(III)-ethylendiamine tetraacetic acid(EDTA) chelate and $CrO_4{^-2}$, we could detect them simultaneously by ion exchange HPLC. Also, we attempted to determine the levels of Cr(III) and Cr(VI) chelated with sodium diethyldithiocarbamate(NaDDTC) by using reversed phase HPLC. The confirmation of Cr(III) and Cr(VI) were checked by fraction collector and nameless atomic absorption spectrometer. The optimal conditions for the formation of Cr(III)-EDTA chelate were two hours incubation period with pH 5. Cr(III)-EDTA and Cr(VI) in EDTA solution were successfully separated by anion exchange column using $Na_2CO_3/NaOH$ mixture as mobile phase. Peaks of Cr(III)-EDTA and Cr(VI) in EDTA were identified at 5 minutes and 7 minutes of retention time respectively by the ion exchange HPLC. The formation of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were twelve hours incubation period. Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were separated by reversed phase column using methanol and water mixture as mobile phase. Peaks of Cr(VI)NaDDTC and Cr(III)-NaDDTC chelates were identified at 13 minutes and 26 minutes of retention time respectively by the reversed phase HPLC. Due to reduction of Cr(VI) to Cr(III), it seems to be not suitable for simultaneous determination of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates by reversed phase HPLS. Simultaneos determination of Cr(III) and Cr(VI) by ion exchange HPLC was more accurate and simple method.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.571-578
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• 2017

Bubbles are generated by the boiling of the cooling water when an accident occurs in the reactor and then in order to measure the void fraction, the Optical Fiber Probe(OFP) and optical camera are used in thermal hydraulic safety research. However, such an optical method is not suitable for measuring the void fraction in a $17{\times}17$ array of fuel rods due to the geometrical limitations. This study was conducted as a preliminary study using x-ray system and various phantoms before applying to rod bundles. Through radiographic and tomographic experiments, the tube voltage of the x-ray generator was 130 kVp and the tube current was 1 mA. In addition, it is possible to measure the hole of 1mm in size visually through the bubble resolution phantom, and it is confirmed that the contrast is relatively decreased in the inside of the freon in the case of the contrast evaluation using the road phantom. However, we could obtain good image without distortion when reconstructing the image. Bubble generation phantom experiments were used to confirm the flow direction of the bubbles and to acquire tomography images. The image J tool was used to measure the void fraction of 18 % for a single tomography image. This study has carried out previous researches for the measurement of the bubble rate around the nuclear fuel and could be used as a basic research for continuous research.

• Investigative Magnetic Resonance Imaging
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• v.16 no.2
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• pp.159-168
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• 2012

The proximity of thoracic aortic aneurysm to the left subclavian artery (LSA) has made the coverage of LSA during thoracic endovascular aortic repair (TEVAR) be essential. Despite controversy concerning the safety of LSA coverage and the indications for LSA revascularizations, the cerebral hemodynamic change after LSA coverage has not been demonstrated. We prospectively examined two patients who would undergo TEVAR with LSA coverage by using 2D cine phase contrast MR imaging. After LSA coverage, the left subclavian steal was properly compensated by the increased flow volumes of both carotid arteries and right vertebral artery, which is the major collateral supply. The total brain supply after TEVAR did not lessen, which showed good correlation with uneventful clinical outcome. Therefore, 2D phase contrast MR imaging can be recommended as a useful technique to evaluate the hemodynamic change of the LSA coverage during TEVAR and to triage the candidate for LSA revascularization.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.354-360
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• 2020

This study examined the factors for sorting miscellaneous cereal crops using a rice-sorting device by analyzing the physical characteristics according to the moisture content. The initial moisture contents of miscellaneous cereal were 16.3, 19.8, and 16.5%, respectively. The samples were used in the experiment after drying to five levels. The width, length, and area of the samples increased with increasing moisture content except for the roundness, and all the prediction models were developed with a first-order linear equation. The bulk density of Italian millet and sorghum increased with increasing moisture content, whereas the bulk density of common millet was unaffected by the change in moisture content. The terminal velocity of the samples increased with increasing moisture content, and a first-order linear equation was used to develop the prediction models. The measured physical properties of the miscellaneous cereal crops based on the changes in the moisture content could be expressed using a first-order experimental model equation. Therefore, the rice-sorting device could be applied to the terminal velocity, but the other device applying the geometrical characteristics and bulk density was required to change the design of the process depending on the type of grain.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.246-251
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• 2016

The use of security lighting that emits spill light is considered a cause of light trespass problems in the residential areas. Therefore, a cutoff panel was installed as an alternative way to reduce light trespass. On the other hand, it has another problem in that it is less effective and is not good enough for aesthetics and safety. In this study, a light cutoff panel was designed and manufactured to reduce the light trespass, and the structure of a proper light cutoff panel was studied. Using a goniophotometer, the light distribution file (IES file) was extracted and the characteristics of light distribution were analyzed using the RELUX program. The results showed that the reduction of spilt light in the backward direction was decreased significantly for all types of light cutoff panels except the coated globe. In the case of a black powder coated light cutoff panel, the forward light caused by light reflected from the surface of the light cutoff panel was also reduced, which means that the black powder coated light cutoff panel is effective in the performance of light cutoff in the forward and backward directions. In addition, the coated glove increased the spilt light in the forward and backward directions because it reflects the upward light to go down. A 90 % accuracy between the measurement value of light trespass and the expected value of the light trespass was obtained from a simulation.