• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.4
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• pp.473-485
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• 1997

Detailed experimental study has been made of air blast kerosene spray flames with and without swirl in combustion air flow. Phase-Doppler detect technique is used to measure Sauter mean diameter, axial component mean and rms velocity, size-velocity correlation, and number density. These measurements are obtained for both nonreacting and reacting cases under several stable flame conditions. The results show that the introduction of swirl to the combustion air modifies the spatial distribution of droplet size, velocity, and number density, and thus alters the flame structure. However, due to the weak swirl intensity, the overall structure of swirling flames are essentially same as that of nonswirling flames. Physical model of structure of air blast atomized spray flames is projected to show that spray flames are composed of three distinct regions: the two-phase mixture region, the main reaction and the intermittent combustion region. Near the atomizer, two phase mixture of droplet and air is formed in the core region. This dense spray region is characterized by high droplet number density and the strong convective effect. There follows the main combustion region where the main flame penetrates within the spray boundary. Main reaction region of these flames are governed by internal group combustion mode. Finally there exists the intermittent combustion region where local group burning or isolated droplet burning occurs.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.4
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• pp.1643-1649
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• 2015

Background: The aim of the present study was to evaluate clinicopathological characteristics of our early stage breast cancer patients who are epidermal growth factor receptor 2 (HER2) overexpressed/amplified (HER2+), the efficacy of trastuzumab treatment and survival results. Materials and Methods: Patients with HER2-positive early stage breast cancer receiving adjuvant trastuzumab were investigated retrospectively. Clinicopathological features of 210 patients and treatment outcome were analysed. To evaluate survival rates, the Kaplan-Meier method was used. Univariate and multivariate analyses were conducted with the Cox regression model. Results: Mean age of the patients was 51.8, 71.9% being postmenopausal. Some 37.6% of patients were node negative, and 31% had T1 tumor size and 52.4% were positive for estrogen receptor. Of 210 patients, 89.5% completed planned 52 weeks adjuvant trastuzumab treatment. The median follow up was 27.5 months (6.0-86.0). Relapse free survival (RFS) was 68.0 months (95% CI: 62.1-74.0) and overall survival (OS) was 74.8 months (95% CI: 69.5-80.1). The 3 year OS for all patients was 92.0% and RFS was 79.6%. During follow up, relapse was detected at the rate of 14.3%. Trastuzumab associated cardiotoxicity was found at the rate of 3.3%. In univariate analyses, larger tumor size and grade III were significantly associated (p<0.05) with RFS. Multivariate analyses of covariates displaying p<0.05 identified grade III as an independent prognostic factor. Conclusions: In the present study, it was established that trastuzumab had a satisfactory safety profile and treatment efficacy as in other clinical studies and that among clinicopathological factors evaluated, only being grade 3 had a significant effect on RFS. The occurrence of relapse with adjuvant trastuzumab makes it necessary to identify molecular predictors, which will define this group better and help explain resistance to anti HER2 based therapies.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.5
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• pp.89-99
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• 2014

The goal of this study was to evaluate sediment reduction effects of VFS (vegetative filter strip) applied for Iksan area in Saemangeum watershed. This study simulated runoff and sediment load from different types of uplands using VFSMOD-W. The general upland characteristics of the study area was investigated to build reasonable scenarios of the simulation. The simulation scenarios were designed by various areas, shapes, and slopes of uplands. Grass mixture was selected as VFS vegetation and the size of VFS was fixed as 10 % of uplands area. Additionally 50mm, 100mm, 150mm of daily rainfall were applied for the runoff and sediment simulation. As results, the calculated runoff and sediment loads were obtained $20.7{\sim}1,030.6m^3$ and 568.4~675,731.4 kg for the range of 0.1~1.0 ha of uplands with 7 % and 15 % slopes. The reduction effects on runoff and sediment were obtained 5~10 % and 21.0~47.7 % respectively from VFS applications. The VFSMOD-W simulations showed that runoff tended to increase as upland area and amount of rainfall increased while sediment increased when slope, length and area of uplands and amount of rainfall increased. These results indicated that rainfall amount and upland size are the critical factors for the generation of runoff and sediment load. In order to support this conclusion, further studies such as, long term monitoring, field experiments, and to calibrate and evaluate the model are necessary.

• Journal of the Korean Chemical Society
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• v.48 no.6
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• pp.616-622
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• 2004

Liposome powders were prepared by a freeze-drying method for the application to the field of drug carrier. The effect of maltose as a liposome stabilizer was studied on the stability and the drug-loading efficiency of the freeze-dried liposome powders. The particle size of liposomes before and after freeze-drying was determined to evaluate the liposome stability. The drug-loading efficiency was measured by Fluorescence spectrophotometer using calcein as a model drug. When maltose was added after the preparation of the liposomes, the liposomes was stable, compared to the case of maltose addition at the hydration procedure. By the addition of maltose, the liposome was stable for 30 days at $4{\sim}37^{\circ}C$, while the particle size of the liposome without maltose increased with time. The liposome showed relatively high stability when the maltose/lipids molar ratio was 3 and 6.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.577-582
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• 2016

In this study, a multiscale method for solving a thermoelasticity problem for interphase in the polymeric nanocomposites is developed. Molecular dynamics simulation and finite element analysis were numerically combined to describe the geometrical boundaries and the local mechanical response of the interfacial region where the polymer networks were highly interacted with the nanoparticle surface. Also, the micrmechanical thermoelasticity equations were applied to the obtained equivalent continuum unit to compute the growth of interphase thickness according to the size of nanoparticles, as well as the thermal phase transition behavior at a wide range of temperatures. Accordingly, the equivalent continuum model obtained from the multiscale analysis provides a meaningful description of the thermoelastic behavior of interphase as well as its nanoparticle size effect on thermoelasticity at both below and above the glass transition temperature.

• Nuclear Engineering and Technology
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• v.25 no.3
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• pp.413-423
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• 1993

This paper reports an experimental study of direct containment heating (DCH) which would occur if the primary system pressure is still high at the time of vessel breach during a light water reactor core melt accident. The experiments were conducted in 1/30-scale cavity models of Kori unit 1 and 2 and Young Kwang unit 3 and 4 nuclear power plants. One 1/20-scale model of the Kori plant was also used to investigate the scaling effect. The primary variables in the experiments were initial vessel pressure, vessel breach size and cavity geometry. It is observed that higher initial pressure and larger breach size enhance the melt dispersal fraction. Also, the cavity geometry appears to affect the dispersal rate greatly. A simple correlation of melt dispersal fraction is proposed in terms of nondimensional effective period. This correlation shows good agreement with the present experimental data, the KAIST data and the BNL data.

• Journal of the Korean Society for Railway
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• v.17 no.6
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• pp.415-422
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• 2014

Reinforced trackbeds are an important layer that has a significant effect on the deformation of the track, therefore, a deeper understanding of reinforced trackbeds is necessary. In this paper, we conduct a large triaxial test in order to evaluate the resilient modulus ($M_R$) of reinforced trackbed materials through considering several factors such as the grain size distribution (GSD) and loading conditions. It is identified that the maximum size of the particle, GSD, and compacted water content affect the $M_R$ but the loading frequency does not. Because these tests are performed with consideration of the field environment, the test results are useful for analyzing tracks including reinforced trackbeds. The data are limited to evaluating the parameters of $M_R$ model; however the parameters of the deviatoric and bulk stress models that can be used in various loading conditions are proposed.

• Biomolecules & Therapeutics
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• v.25 no.2
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• pp.149-157
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• 2017

The interleukin-1 receptor antagonist (IL-1RA) is a potential stroke treatment candidate. Intranasal delivery is a novel method thereby a therapeutic protein can be penetrated into the brain parenchyma by bypassing the blood-brain barrier. Thus, this study tested whether intranasal IL-1RA can provide neuroprotection and brain penetration in transient cerebral ischemia. In male Sprague-Dawley rats, focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) for 1 h. The rats simultaneously received 50 mg/kg human IL-1RA through the intranasal (IN group) or intraperitoneal route (IP group). The other rats were given 0.5 mL/kg normal saline (EC group). Neurobehavioral function, infarct size, and the concentration of the administered human IL-1RA in the brain tissue were assessed. In addition, the cellular distribution of intranasal IL-1RA in the brain and its effect on proinflammatory cytokines expression were evaluated. Intranasal IL-1RA improved neurological deficit and reduced infarct size until 7 days after MCAO (p<0.05). The concentrations of the human IL-1RA in the brain tissue 24 h after MCAO were significantly greater in the IN group than in the IP group (p<0.05). The human IL-1RA was confirmed to be co-localized with neuron and microglia. Furthermore, the IN group had lower expression of $interleukin-1{\beta}$ and tumor necrosis $factor-{\alpha}$ at 6 h after MCAO than the EC group (p<0.05). These results suggest that intranasal IL-1RA can reach the brain parenchyma more efficiently and provide superior neuroprotection in the transient focal cerebral ischemia.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.1
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• pp.77-82
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• 2013

A cyclone separator has been widely used in various industrial processes for removing fine particulate matter because it is easy to fabricate, cost effective, and adaptable to extremely harsh conditions. However, owing to the complex flow field in cyclones, a complete understanding of the detailed mechanisms of particulate removal has not yet been gained. In this study, a theoretical analysis was performed for calculating the collection efficiency and cut-off size in cyclones by taking into account the effects of geometrical and flow parameters. The collection efficiency and cut-off size values predicted by the theoretical model showed good agreement with experimental measurements for particles with a diameter of $0.5-30{\mu}m$. It was also revealed that the surface friction, along with the flow and geometrical parameters, has a significant effect on the cyclone performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.9
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• pp.2967-2981
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• 2014

Device-to-Device (D2D) communication is a technology component for long-term evolution-advanced (LTE-A). In D2D communication, users in close proximity to each other can communicate directly without going through a base station; such direct communication can improve spectral efficiency. Although D2D communication brings improvement in spectral efficiency, it also causes interference to the cellular network as a result of spectrum sharing. In particularly, D2D communication can generate interference for each D2D pair when the common wireless medium in a co-located limited area is accessed. Even though the interference management for between the D2D pair and cellular networks has been proposed, the interference reducing methods have still not been fully studied for the D2D pairs. In this paper, we investigate the problem of D2D pair coexistence in which interference is considered between D2D pairs. Using a signal to interference model for a target D2D pair, we provide an analysis of the aggregated throughput of a dense D2D network. For a target D2D pair, we assume that the desired signal and interference signals obey multipath fading and shadow fading. Through analysis, we demonstrate the effect of cluster size such as the number of D2D pairs and the size of the considered area on the network performance. The analytical results are compared with computer simulations. Our work can be used for a rough guideline for controlling the system throughput in a dense D2D network environment.