• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.252-254
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• 2002

A new protocol for dosimetry in external beam radiotherapy is published by the Japan Society of Medical Physics (JSMP) in 2002. The protocol deals with proton and heavy ion beams as well as photon and electron beams, in accordance with IAEA Technical Report Series No. 398. To establish inter-institutional uniformity in proton beam dosimetry, an intercomparison program was carried out with the new protocol. The absorbed doses are measured with different cylindrical ionization chambers in a water phantom at a position of 30-mm residual range for a proton beam, that had range of 155 mm and a spread out Bragg peak (SOBP) of 60-mm width. As a result, the intercomparison showed that the use of the new protocol would improve the +/- 1.0 % (one standard deviation) and 2.7 % (maximum discrepancy) differences in absorbed doses stated by the participating institutions to +/- 0.3% and 0.9 %, respectively. The new protocol will be adopted by all of the participants.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.432-435
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• 2002

We have developed and proposed the heavy ion CT system which consists of fluorescent screen and CCD camera equipped with image intensifier. In our system, we have measured the residual range of particles that passed a phantom and reconstructed the CT image for the distribution of relative stopping power by filtered back projection method with Shepp '||'&'||' Logan filter. The heavy ion $\^$12/C accelerated up to 400 MeV/u by HIMAC (Heavy Ion Medical Accelerator in Chiba) was used. Intensity of the beam output changes like macro pulse, the period being 3.3 sec and the width being 2 sec. The series of data was acquired in synchronizing with the pulse, leading to the improvement of S/N in the CT image. The fundamental performance was experimentally evaluated in the proposed system. The spatial resolution was estimated to be about 1 mm and the density resolution (electron density referred to water) to be about 0.01.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.3
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• pp.79-88
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• 2003

For the construction of PC bridge piers the implementation of 1992 seismic provisions, longitudinal steels were practically lap-spliced in the plastic hinge region. Experimental investigation was conducted ductility of evaluate the seismic earthquake-experienced reinforced concrete columns with 2,5 aspect ratio. Six test specimens were mode with test parameters: confinement ratios, lap splices, and retrofitting FRP materials. They were damaged under series of artificial earthquakes that could be compatible in Korean peninsula. Directly after the pseudo-dynamic test, damaged columns were retested under inelastic reversal cyclic loading simultaneously under a constant axial load, P＝0.1f$\_$ck/A$\_$g/. Residual seismic performance of damaged columns was evaluated and compared to that of the corresponding original columns. Test results show that PC bridge piers with lap-spliced longitudinal steels appeared to fail at low ductility. This was due to the debonding of the lap splice, which resulted from insufficient development of the longitudinal steels. The specimens externally wrapped with composite FRP straps in the potential plastic hinge region indicated significant improvement both in flexural strength and displacement ductility.

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.71-94
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• 1987

This study was carried out to investigate the sound distortion following the alternation of the palatal plate thickness. For this study, 2 healthy male subjects (24-year-old) were selected. Born in Seoul, they both spoke Seoul dialect. First, their sounds of /na(나)/, /da(다)/, /1a(라)/, /ja(자)/, /cha(차)/, /ta(타)/, without inserting plates were recorded, and then the sounds with palatal plates of different thickness were recorded, successively. The plate was fabricated in 3 types, each palatal thickness being 1.0mm, 2.5mm, dentoalveolar portion 2.5mm, other residual portion was 1.0mm, successively. Each type plates named B, C, D-type, in succession. Series of analysis were administered through Computer(16 bit) to analyze the sound distortions. These experiments were analyzed by the LPC (without weighting, pre-weighting, post-weighting) of the consonants, vowels portion, formant frequency of the vowels and word duration of the consonants. The findings led to the following conclusions: 1. There was no correlation of the distortion rate on the 2 informants. 2. Generally, vowels were not affected by the palatal plate thickness in the formant analysis, however, more distortion was detected in the LPC analysis, especially C, D-type plates. 3. Consonants distortion was more evident in the C, D-type plate. 4. The second formant was most disturbed and reduced in the all consonants with insertion of the palatal plate, especially C, D-type plate. 5. Word duration was shortened in the plate inserted(except /ja/, /cha/), especially C, D-type. 6. It was found that dentoalveolar, hard palatal sounds were severely distorted in plate inserted, and they were mainly affected by the dentoalveolar portion thickness. 7. There was correlation between palatal thickness and consonants quality.

• Journal of Korean Neurosurgical Society
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• v.54 no.2
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• pp.86-92
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• 2013

Objective : Surgical results for anterior choroidal artery (AChA) aneurysms have previously been reported as unsatisfactory due to inadvertent occlusion of the AChA, while the low incidence of AChA aneurysms hampers the accumulation of surgical experience. The authors reviewed their related surgical experience to document the ischemic complications and surgical outcomes. Methods : Identification of the AChA at its origin by rigorous visual scrutiny, careful microdissection, and meticulous clip placement to avoid the AChA origin are all crucial surgical maneuvers. A retrospective review of a surgical series of 62 consecutive cases of an AChA aneurysm between 2004 and 2012 was performed. Results : All patients, except for five (8.1%) with a small residual neck, showed complete aneurysm obliteration in postoperative angiographic evaluations. There was no incidence of procedure-related permanent AChA syndrome or oculomotor nerve palsy, while three (4.8%) patients suffered from transient AChA syndrome. The clinical outcomes [the 3-month modified Rankin Scale (mRS)] of the patients were related to their preoperative World Federation of Neurologic Surgeons (WFNS) grade. As regards the 3-month mRS, significant differences were found between patients with an unruptured aneurysm (WFNS grade 0; n=20), good-grade subarachnoid hemorrhage (WFNS grade 1-3; n=30), and poor-grade subarachnoid hemorrhage (WFNS grade 4-5; n=4). Conclusion : In surgical treatment of AChA aneurysms, a risk of AChA insufficiency can be minimized by taking every precaution to preserve the AChA patency and intraoperative monitoring. In addition, the surgical outcome is primarily determined by the preoperative clinical state.

• Journal of Powder Materials
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• v.24 no.6
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• pp.464-471
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• 2017

A metal mesh TCE film is fabricated using a series of processes such as UV imprinting of a transparent trench pattern (with a width of $2-5{\mu}m$) onto a PET film, filling it with silver paste, wiping of the surface, and heat-curing the silver paste. In this work nanosized (40-50 nm) silver particles are synthesized and mixed with submicron (250-300 nm)-sized silver particles to prepare silver paste for the fabrication of metal mesh-type TCE films. The filling of these silver pastes into the patterned trench layer is examined using a specially designed filling machine and the rheological testing of the silver pastes. The wiping of the trench layer surface to remove any residual silver paste or particles is tested with various mixture solvents, and ethyl cellosolve acetate (ECA):DI water = 90:10 wt% is found to give the best result. The silver paste with 40-50 nm Ag:250-300 nm Ag in a 10:90 wt% mixture gives the highest electrical conductance. The metal mesh TCE film obtained with this silver paste in an optimized process exhibits a light transmittance of 90.4% and haze at 1.2%, which is suitable for TSP application.

• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.54-62
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• 2004

In order to enhance the efficiency of removal a series of ElectroKinetic Remediation (EKR) tests on ferrous soil contaminated by lead are carried out using acids, chelates and surfactant as flushing agents. The test results indicate that pH in the electrolyte rapidly reached at steady state as the introduce of flushing solution of the lower pH, the type of flushing solution have no effect the distribution of electrical voltage within the sample but the increasing of solution concentration increases it at x/L=0.9. In the distribution of the residual lead in the sample SDS is the highest. Also, the removal efficiency for acetic acid concentration of 1mM Is the highest but the concentration of acetic acid significantly have no effect.

• Ocean Science Journal
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• v.42 no.3
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• pp.153-163
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• 2007

This study is based on a series of numerical modeling experiments to understand the tidal circulation in the Kangjin Bay (KB). The tidal circulation in the KB is mostly controlled by the inflow from two channels, Noryang and Daebang which introduce the open ocean water into the northern part of the KB with relatively strong tidal current, while in the southern part of the KB, shallowest region of the entire study area, weak tidal current prevails. The model prediction of the sea level agrees with observed records at skill scores exceeding 90 % in terms of the four major tidal constituents (M2, S2, K1, O1). However, the skill scores for the tidal current show relatively lower values of 87, 99, 59, 23 for the semi-major axes of the constituents, respectively. The tidal ellipse parameters in the KB are such that the semi-major axes of the ellipse for M2 range from 1.7 to 38.5 cm/s and those for S2 range from 0.5 to 14.4 cm/s. The orientations of the major-axes show parallel with the local isobath. The eccentricity values at various grid points of ellipses for M2 and S2 are very low with 0.2 and 0.06 on the average, respectively illustrating that the tidal current in the KB is strongly rectilinear. The magnitude of the tidal residual current speed in the KB is on the order of a few cm/s and its distribution pattern is very complex. One of the most prominent features is found to be the counter-clockwise eddy recirculation cell at the mouth of the Daebang Channel.

• Economic and Environmental Geology
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• v.26 no.4
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• pp.445-454
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• 1993

The Keumseongsan caldera is composed of the Cretaceous sedimentary rocks of the Gyeonesang Supergroup, volcanic rocks of the Yucheon Group and basic dykes. The Keumseongsan caldera is formed by subsidence of volcanic rocks, and arc fault developed late. Also, synistral strike-slip fault ($N60^{\circ}W$) developed. Volcanic rocks belong to subalkaline rocks and calcalkaline magma series. First tuffaceous breccia erupted before 71.4 Ma and cavity of magma chamber caused subsidence, which formed arc fault. Basaltic lava erupted at 71.4 Ma and residual fluids containing Fe, As, Pb, Zn and Cu metal elements built the Ohto deposits, which are dated to be 70.5 Ma based on K-Ar age for sericite. Tuffaceous breccia and tuff erupted between 70.5 and 67 Ma. When volcanic eruption became weakened, cavity in site of magma chamber brought subsidence. Rhyolite intruded and erupted at 67 Ma, and intrusive rhyolite intruded according to arc faults, also. Hydrothermal fluids containing Fe, As, Pb, Zn, Cu, Sb, Bi, Au and Ag formed the Tohyeon deposits. K-Ar age for sericite from the Tohyeon mine gives 66.0 Ma. Results of field exploration, geochemical analyses of volcanic rocks support mineralization possibility by volcanism. Especially, age of volcanism and mineralization are well in coincidence with results of K-Ar age dating. By these results, Ohto Cu mineralization is regarded to be associcated with basaltic rocks, while Tohyeon Cu mineralization with rhyolitic rocks.

• Journal of the Korean earth science society
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• v.30 no.6
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• pp.692-698
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• 2009

Wavelet transform has been widely used in terms that it may overcome the shortcoming of conventional Fourier transform. Fourier transform has its difficulty to explain how the transformed domain, frequency, is related with time. Traditional semblance technique in Fourier transform was devised to compare two time series on the basis of their phase as a function of frequency. But this method is known not to work well for the non-stationary signal. In this study, we present two applications of the wavelet-based semblance method to geophysical data. Firstly, we show filtered geomagnetic signal remained with components of high correlation to each observatory. Secondly, highly correlated residual signal of gravity and magnetic survey data, which are also filtered by this semblance method, is present.