• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1801-1808
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• 2006

The interaction between whey carrier protein $\beta$-lactoglobulin type A and B (BLG-A and -B) and 2,2'-bipyridin n-hexyl dithiocarbamato Pd(II) nitrate (BPHDC-Pd(II)), a new heavy metal complex designed for anticancer property, was investigated by fluorescence spectroscopy combined with chemometry and circular dichroism (CD) techniques. A strong fluorescence quenching reaction of BPHDC-Pd(II) to BLG-A and -B was observed. Hence, BPHDC-Pd(II) complex can be bound to both BLG-A and -B, and quench the fluorescence spectra of the proteins. The quenching constant was determined using the modified Stern-Volmer equation. The binding parameters were evaluated by fluorescence quenching method. The results of binding study provided evidences presence of two and three sets of binding sites on the BLG-B and -A, respectively, for BPHDC-Pd(II) complex. Using fluorescence spectroscopy and chemometry, the ability of BLG-A and -B to form an intermediate upon interaction with BPHDC-Pd(II) complex was assessed. CD studies displayed that under influence of different concentrations of BPHDC-Pd(II) complex, the regular secondary structure of BLG-B had no significant changes, whereas for BLG-A a transition from $\alpha$-helix to $\beta$-structure was appeared. The results for both of BLG-A and -B displayed that BPHDC-Pd(II) complex can induce a conformational transition from the native form to an intermediate state with a slightly opened conformation, which is detectable with chemometry analyses.

• The Journal of Korean Society for Radiation Therapy
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• v.10 no.1
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• pp.88-93
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• 1998

Multileaf collimator is essential equipment in conformal radiation therapy, however the use is limitted by increase of penumbra width and undulating dose distribution at the field edge. The purpose of this study is to improve the penumbra and dose distribution in the multileaf collimator field edge. Measurement were performed with X-omat V film in solid water phantom using 6MV photon beam from Siemens linear accelerator. All the measurement were made along the central axis of $5{\times}5cm,\;10{\times}10cm$ circular field for constant SSD of 100 cm. To improve the penumbra and dose distribution collimator was rotated by 15 degrees from 0 to 90 degrees (collimator rotation method) and center was shifted to the longitudinal direction by fourth of lead width (center shift method). We compare the penumbra and dose distribution at the field edge to alloy block. Dose distribution and penumbra width at the feild edge of MLC showed undulated dose pattern and increased penumbra compared with alloy block. However, in the collimator rotation method and center shift method we abtained simular results with alloy block. Through the study we expected that clinical use of MLC will be increase.

• Advances in concrete construction
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• v.8 no.3
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• pp.173-185
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• 2019

This article presents a comparative study of the effect of steel layouts on the seismic behavior of transition steel-concrete composite connections, both experimental and analytical investigations of concrete filled steel tube-reinforced concrete (CFST-RC) and steel reinforecd concrete-reinforced concrete (SRC-RC) structures were conducted. The steel-concrete composite connections were subjected to combined constant axial load and lateral cyclic displacements. Tests were carried out on four full-scale connections extracted from a real project engineering with different levels of axial force. The effect of steel layouts on the mechanical behavior of the transition connections was evaluated by failure modes, hysteretic behavior, backbone curves, displacement ductility, energy dissipation capacity and stiffness degradation. Test results showed that different steel layouts led to significantly different failure modes. For CFST-RC transition specimens, the circular cracks of the concrete at the RC column base was followed by steel yielding at the bottom of the CFST column. While uncoordinated deformation could be observed between SRC and RC columns in SRC-RC transition specimens, the crushing and peeling damage of unconfined concrete at the SRC column base was more serious. The existences of I-shape steel and steel tube avoided the pinching phenomenon on the hysteresis curve, which was different from the hysteresis curve of the general reinforced concrete column. The hysteresis loops were spindle-shaped, indicating excellent seismic performance for these transition composite connections. The average values of equivalent viscous damping coefficients of the four specimens are 0.123, 0.186 and 0.304 corresponding to the yielding point, peak point and ultimate point, respectively. Those values demonstrate that the transition steel-concrete composite connections have great energy dissipating capacity. Based on the experimental research, a high-fidelity ABAQUS model was established to further study the influence of concrete strength, steel grade and longitudinal reinforcement ratio on the mechanical behavior of transition composite connections.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.3
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• pp.31-40
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• 2001

Low-order panel methods are being used to design marine propellers. Since the potential value over each panel for these methods is assumed to be a constant, the accuracy of prediction is known to be limited. Therefore, a higher order boundary element method(HOBEM) has been studied to enhance the accuracy of prediction. In this paper, a HOBEM representing the body boundary surfaces and physical quantities by a 9-node Lagrangian shape function is employed to analyse the flow around marine propellers in steady potential flow. First, the numerical results for a circular wing with thickness variations are compared with Jordan's linear solution. Then, the computational results of two propellers(DTRC 4119 & DTRC 4842 propeller) are compared with the experimental and numerical results published. The pressure distribution on the surface of the propeller is also compared with experimental data.

• Journal of the Korean Geotechnical Society
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• v.35 no.6
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• pp.27-38
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• 2019

Bearing capacity of a pile in homogeneous soil is the sum of end bearing and skin resistance, and the skin resistance is more prominent in sandy soil. Bearing capacity of a pile in pile groups especially in sandy ground should be designed under the consideration of the influence by the adjacent piles. In this study, the end bearing capacity of a pile in pile groups was experimentally investigated. For this purpose, piles were installed in sandy ground in a circular test box, and end bearing - settlement behavior of the pile was measured while the pile was loaded. As the results, end bearing - settlement relation curves of the piles showed a distinct limit value. Limit value of the end bearing was little affected by skin friction and pile diameter, and it became a constant value as pile penetrates deeper. End bearing was not affected by the adjacent piles in a group of piles, when their clearance was larger than the pile diameter.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.19-28
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• 2021

In rotating detonation engine(RDE), only the detonation wave is moving around the outer wall of the combustor. Neither a mechanical part nor flow is rotating in RDE. Thus, the RDE cross section is not necessary to be circular, but arbitrary closed section is possible. A RDE of tri-arc cross section is designed and As an example of an arbitrary cross sectioned RDE, a RDE of tri-arc cross section is designed in this study, and operational and performance characteristics were examined experimentally. The rotation of the detonation wave is confirmed by dynamic pressure sensor and high-speed camera, while the characteristics of the detonation wave were investigated at the concave and convex surfaces. In the present study, the thrust level of 17.0 N to 96.0 N was obtained depending on the mass flow rate.

• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1619-1624
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• 2018

Laser ablation may provide a minimally invasive palliative treatment for pancreatic cancer. The aim of the current study was to assess the feasibility of a 532-nm laser equipped with a cylindrical light diffuser for the treatment of pancreatic cancer. Monolayers of BxPC-3 human pancreatic cancer cell were exposed to 532 nm laser light. Power levels of 5 - 7 W were used to uniformly target the entire cell colonies for 60 and 120 seconds. The cells were incubated for 24 hours after treatment and viabilities were determined by using a MTT assay. Laser ablation was performed by using the cylindrical light diffuser on six pancreatic tumor tissues obtained from pancreatic cancer xenograft mouse models, which were exposed to the 532 nm light at 5W or 7W for 10 to 30 seconds. In the in vitro study, the survival rates of the pancreatic cancer cells were reduced by 6.6% to 98.9% after the treatment, and the survival rates were reduced by increasing laser power and/or irradiation time. In the pancreatic tumor tissues, a homogenous circular ablation zone was observed in all tumors and the ablation distance induced by the laser irradiation showed to be constant from the diffuser to all directions (standard deviation, 0.3 - 1.3 mm). Ablation distance and area increased with increasing laser power and/or irradiation time. The 532 nm laser effectively killed pancreatic cancer cells, and the cylindrical light diffuser was found to be suitable for laser ablation as it provided uniform ablation in pancreatic cancer.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.7
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• pp.14-21
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• 2001

In this paper, we designed and fabricated C-band bandpass filter using dielectric resonators. From waveguide cutoff frequency which applied the region between adjacent dielectric resonators, the height of cavity is determined. The cavity's diameter is determined to the twice of dielectric resonator? diameter considering the conductor loss. The resonant frequency of the DR cavity is calculated with non decaying mode analysis. Conventionally, cylindrical dielectric resonator is analysed by Cohn's model which use the decaying mode in the region between dielectric resonator wall and circular cavity wall, which is an approximated method. The external quality factor, $Q_{ex}$ has found with simulation result using Ansoft's Maxwell simulation tool. The designed filter using dielectric resonators with dielectric constant of 45 has the passband center at 5.065GHz. The bandpass filter using dielectric resonators has about 1dB insertion loss, 20MHz bandwidth and more than 30dB attenuation at $f_0+15MHz$.

• Journal of the Korean GEO-environmental Society
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• v.17 no.11
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• pp.15-21
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• 2016

Nowadays, some studies have been performed for rockbolt method widely used in Korea. To make large slopes, tunnels or rock structures stable, supporting systems, such as anchor bolt, rock bolt which are developed recently, are commonly used. In this study, laboratory pullout tests were carried out to compare the characteristics of rock bolt that is most widely used with ones of rock bolt by newly developed circular model testers. Re-pullout test for the rock bolt in which loading and unloading cycles are repeated several times showed that the maximum pullout load is almost constant irrespective of the number of loading cycles, which may be due to no failure between rock bolt and filler that is filled with soils and concrete as a substitute. A development of rock bolt fillers as supporters using to protect people in tunnels and slopes is reviewed as a probable man-made hazard after excavation works. The functions of the grouted rock bolts associated with reinforcement effects also should be assessed in this study, which develop the sealing apparatus preventing from overflowing mortar out of a rock bolt hole for securing safety in the tunnel and slopes in order to secure stability named the sealing packer.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.401-412
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• 2008

Simulations of three-dimensional numerical wave tank are performed to investigate wave force acting on a large cylindrical structure and consequent wave deformation, which are induced by bore after breaking waves. The numerical model is based on the three-dimensional Navier-Stokes equations with a finite-difference method combined with a volume of fluid(VOF) method, which is capable of tracking the complex free surface, including wave breaking. In order to promote wave breaking of the incident wave, the approach slope was built seaward of the structure with a constant slope and a large cylindrical structure was installed on a flat bed. The incident waves were broken on the approach slope or flat bed by its wave height. In the present study, all waves acting on the large cylindrical structure were limited to breaking bore after wave breaking. The effects of the position of the structure and the incident wave height on the wave force and wave transformations were mainly investigated with the concern of wave breaking. Further, the relations between the variation of wave energy by wave propagation after wave breaking and wave force acting on the structure were discussed to give the understanding of the full-linear wave-structure interactions in three-dimensional wave fields.