• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.1
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• pp.1-13
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• 2015

Despite recent progresses in nanoparticle-based drug delivery systems, there are still many unsolved limitations. Most of all, a major obstacle in current nanoparticle-based drug carrier is the lack of sufficient drug delivery into target cells due to various biological barriers, such as: extracellular matrix, endolysosomal barrier, and drug-resistance associated proteins. To circumvent these limitations, several research groups have utilized photochemical internalization (PCI), an extension of photodynamic therapy (PDT), in design of innovative and efficient nano-carriers drug delivery. This review presents an overview of a recent research on utilization of PCI in various fields including: anti-cancer therapy, protein delivery, and tissue engineering.

• Journal of Korean Society for Quality Management
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• v.39 no.2
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• pp.305-312
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• 2011

Kano model has been widely used to identify and classify customer attributes of a product or a service. The first step of Kano model application is the derivation of customer attributes, and brainstorming has been used conventionally for the purpose. A typical advantage of brainstorming is to get many ideas in a relatively short period, but the practicability of the derived ideas are known to be not so good. The derivation of good and practical ideas is important for the successful use of Kano model. Wish list, bug list and forced connection method as well as brainstorming were applied to PMP(Portable Multimedia Player) in order to derive customer attributes. To compare the idea generation methods, the derived attributes are classified and compared using Kano model.

• Earthquakes and Structures
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• v.10 no.3
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• pp.629-643
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• 2016

Among all the natural disasters, earthquakes are the most destructive calamities since they cause a plenty of injuries and economic losses leaving behind a series of signs of panic. The present study highlights the moment-curvature relationships for the structural elements such as beam and column elements and Non-Linear Static Pushover Analysis of RC frame structures since it is a very simplified procedure of non-linear static analysis. The highly popular model namely Mander's model and Kent and Park model are considered and then, seismic risk evaluation of RC building has been conducted using SAP 2000 version 17 treating uncertainty in strength as a parameter. From the obtained capacity and demand curves, the performance level of the structure has been defined. The seismic fragility curves were developed for the variations in the material strength and damage state threshold are calculated. Also the comparison of experimental and analytical results has been conducted.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.1
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• pp.80-83
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• 2022

This paper proposes an initial rotor polarity detection algorithm of a single-phase permanent magnet synchronous motor (SP-PMSM) related to stable open-loop starting for sensorless operation. Generally, the SP-PMSM needs an asymmetric air-gap structure to can avoid the initial starting failure at zero torque point. Therefore, the rotor polarity information can be obtained by using the DC offset current direction of a stator current through a high frequency voltage injection into an SP-PMSM with an asymmetric air gap. In this paper, the proposed rotor initial polarity detection algorithm is verified through several experimental results.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.861-864
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• 1999

We designed and fabricated microstrip line fed QMSAs(Quarter-Wavelength Microstrip Antenna) for 850〔MHz〕 band on the CGP-500 Copper-clad Laminates substrate (CHUKOH company) with $\varepsilon$$_{r}$＝2.6, H＝1.6〔mm〕( $\pm$0.08), where the width of the radiation patch is identical with that of the ground plane. The resonant frequencies and the return losses were measured by reducing the PSW(Partially Shorted Width) to 0〔mm〕, step by step, when the microstrip line width was 1.47〔mm〕, 2.93〔mm〕and 4.4〔mm〕separately. As a result, a good characterized antenna with a 11% reduced resonant length and a return loss -29.44〔㏈〕 was obtained when the total PSW was in the range of 70% of radiated patch width, compared to the conventional QMSA.A.

• Structural Engineering and Mechanics
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• v.72 no.3
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• pp.395-408
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• 2019

Engineered structures built in seismic-prone areas are affected by aftershocks in addition to mainshocks. Although aftershocks generally are lower in magnitude than that of the mainshocks, some aftershocks may have higher intensities; thus, structures should be able to withstand the effect of strong aftershocks as well. This seismic scenario arises for far-field mainshock along with near-field aftershocks. In this study, four 2D reinforced concrete (RC) frames with different numbers of stories were designed in accordance with the current Iranian seismic design code. As a way to evaluate the seismic response of the case-study RC frames, the inter-story drift ratio (IDR) demand, the residual inter-story drift ratio (RIDR) demand, the Park-Ang damage index, and the period elongation ratio can be useful engineering demand parameters for evaluating their seismic performance under mainshock-aftershock sequences. The frame models were analyzed under a set of far-field mainshock, near-fault aftershocks seismic sequences using nonlinear dynamic time-history analysis to investigate the relationship among IDR, RIDR, Park-Ang damage index and period ratio experienced by the frames. The results indicate that the growth of IDR, RIDR, Park-Ang damage index, and period ratio in high-rise and short structures under near-fault aftershocks were significant. It is evident that engineers should consider the effects of near-fault aftershocks on damaged frames that experience far-field mainshocks as well.

• The Korea Journal of Herbology
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• v.28 no.5
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• pp.87-93
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• 2013

Objectives : We recently have reported that constituents of OMC-2010 have an immuno-modulatory effects via inhibiting tumor necrosis factor (TNF)-alpha and interleukin (IL)-5. In this study, based on previous data, we investigated the effects of combinations with each OMC constituents on splenocyte cytotoxicity, cytokine productions, and ovalbumin (OVA) induced experimental allergic asthma. Methods : Mouse splenocytes were pre-treated with ethanol extract of constituents of Rehmannia glutinosa (RG), Pinellia ternata (PT), Schisandra chinensis (SC). We made 4 combinations using RG, PT, and SC (A;1:1:1, B;2:1:1, C;1:2:1, D;1:1:2). The cells were pretreated with A, B, C, or D for 1 h, then stimulated with lipopolysaccharide (LPS, $1{\mu}g/ml$) for 48 h. Then the cells were harvested for real-time reverse transcription polymerase chain reaction to detect cytokine productions. Then using effective combination from RG, PR and SC, we administrated the combination orally, then challenged with OVA to induce asthma. Then we analyzed the airway hyper-reactivity (AHR), lung histology and lung TNF-${\alpha}$ and IL-5 mRNA. Results : A. B. C. and D did not showed significant cytotoxicity on splenocytes. Pre-treatment of A inhibited the expression of TNF-${\alpha}$ and IL-5 significantly, but not B, C, and D. In experimental asthma, administration of A significantly inhibited the increase of AHR, lung damage, TNF-${\alpha}$ and IL-5 expression. Conclusions : Theses results could suggest that inhibitory effects of the ideal combination with RG, PT and SC (1:1:1) could be applied to treatment of asthma and study of asthma mechanisms.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.3 no.1
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• pp.71-84
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• 2005

This study had performed with purposes to analyze the influence of the change of vestibular sens, visual and proprioceptive sense to the postural sway, so as to supply the necessary clinical materials through developing the physical therapeutic interventions and assessment format for the diabetic neuropathy patients. The sample consisted of fifteen diabetic neuropathy patients with sensory disorder in their lower limbs and fifteen age-matched normal control group. Then the effect of the GVS and the visual cue open and closed to the postural sway were measured by CoP. The summary of the comparison results were obtained below. In the comparison of diabetes neuropathy patients group and age matched normal control group, however diabetes neuropathy patients group had a decrease in superficial tactile sense(p<.001) and nerve conduction velocity(p<.001), they were able to control the posture and walk. So it is, diabetes neuropaty patients had more disturbance compared with AMC group on at a hard surface, particularly in the visual cue open(p<.001) and visual cue closed(p<.01). Moreover, since diabetes neuropathy patients group had more differences in visual cue open and closed(p<. 01), GVS(p<.01), it meant that they're affected largely by vestibular sense, visual sense. In addition, since there're the largest change in doubled sense disturbance such as visual cue open and closed under GVS, it meant that compensation of other senses were quite important for the diabetes neuropathy patients' postural control. In the conclusion, diabetes neuropathy patients who decrease or lose the somatosensory system, sensory training of visual and vestibular system are likely to be quite essential to control the posture and balance.

• Journal of the Korean Electrochemical Society
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• v.14 no.2
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• pp.117-124
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• 2011

We demonstrate a new surface modification of high-voltage lithium cobalt oxide ($LiCoO_2$) cathode active materials for lithium-ion batteries. This approach is based on exploitation of a polarity-tuned gel polymer electrolyte (GPE) coating. Herein, two contrast polymers having different polarity are chosen: polyimide (PI) synthesized from thermally curing 4-component (pyromellitic dianhydride/biphenyl dianhydride/phenylenediamine/oxydianiline) polyamic acid (as a polar GPE) and ethylene-vinyl acetate copolymer (EVA) containing 12 wt% vinyl acetate repeating unit (as a less polar GPE). The strong affinity of polyamic acid for $LiCoO_2$ allows the resulting PI coating layer to present a highly-continuous surface film of nanometer thickness. On the other hand, the less polar EVA coating layer is poorly deposited onto the $LiCoO_2$, resulting in a locally agglomerated morphology with relatively high thickness. Based on the characterization of GPE coating layers, their structural difference on the electrochemical performance and thermal stability of high-voltage (herein, 4.4 V) $LiCoO_2$ is thoroughly investigated. In comparison to the EVA coating layer, the PI coating layer is effective in preventing the direct exposure of $LiCoO_2$ to liquid electrolyte, which thus plays a viable role in improving the high-voltage cell performance and mitigating the interfacial exothermic reaction between the charged $LiCoO_2$ and liquid electrolytes.

• Journal of Hydrogen and New Energy
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• v.31 no.4
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• pp.337-344
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• 2020

Worldwide, there is a significant surge in the efforts for addressing the issue of global warming; the use of renewable energy is one of the solutions proposed to mitigate global warming. However, severe volatility is a critical disadvantage, and thus, power-to-gas technology is considered one of best solutions for energy storage. Hydrogen is a popular candidate from the perspective of both environment and economics. Accordingly, a hydrogen production system based on renewable energy sources is developed, and the economics of the system are assessed. The result of the base case shows that the unit cost of hydrogen production would be 6,415 won/kg H₂, with a hydrogen production plant based on a 100 MW akaline electrolyzer and 25% operation rate, considering renewable energy sources with no electricity cost payment. Sensitivity study results show that the range of hydrogen unit cost efficiency can be 2,293 to 6,984 Won/kg H₂, depending on the efficiency and unit cost of the electrolyzer. In case of electrolyzer operation rate and electricity unit cost, sensitivity study results show that hydrogen unit cost is in the range 934-26,180 won/kg H₂.