• The Journal of the Korea Contents Association
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• v.6 no.6
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• pp.136-143
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• 2006

Contemporary society demands the ability to cope with the change competitively to the designer which is being accelerated of change and various media are emerging. The web design field which is one of the core design industry field of the contemporary society is needing the conversion from manufacturing technology specialization into creative design development composition. Generally, creative design development ability can be learned by studying. So, creativity development education is needed to develop creative design. Creative thought training is perceived as the core condition for competitive design and the education method for this is being proceeded multiply. But the study for design concept is lacking concretely. By this, this paper is to study the model which helps setting the design concept deduction creatively by instigating new ways of thought. The concept development process suggested in the study procedure systemizes the course for creative web design concept deduction and expects it to be utilized in design development to reinforce competitiveness.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.851-856
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• 2008

Construction of large-scale container ports with the productivity improvements in container cranes shortened time of staying port to increase the level of service it harbors efforts accelerated. About container crane system exerted on the input, which is designed to look good performance considering the states feedback control system. The states observer designed of container cranes state variables that are expected to measurement noise or particular measurement signal. In the status of existing research, the feedback gain matrix and the state observer gain matrix are searched by being separated solving. But the feedback gain matrix and the state observer gain matrix are searched by RCGAs at once that be used robust search method in this paper.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.459-462
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• 2008

In manufacture of slurry fuel, the effects of process parameters on the carbon dispersion stability have been investigated. The particle size and contents of the carbon slurry taken from 3 (top, medium, bottom) positions in fuel reservoir were analyzed to estimate the dispersion of the carbon in Jet A-1. Through the application of various additives, it was found that NB463S84 additive showed the best dispersion and stability of carbon at accelerated gravity condition. The mixer performance was compared by the observation of height change of carbon-containing layer and measurement of particle sizes at the same conditions. Application of the mixing conditions obtained from the lab-scale to bench scale manufacture confirmed the practical feasibility of our research.

• Archives of Pharmacal Research
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• v.22 no.3
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• pp.288-293
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• 1999

Postabsorptive serum iron level was determined after oral administration of the compounds to human. In serum and whole blood, $Fe^{3+}$ was measured by ion chromatography (IC) using a pyridine-2,6-dicarboxylic acid (PDCA) as an eluent. The serum sample solutions were pretreated with I N HCI and 50% TCA. The whole blood sample solutions were treated with 3 N HCI for 30 min at $125^{\circ}C$. The limit of detection (LOD) of the IC technique is $0.2 {\mu}M$ for$Fe^{2+}$and 0.1 $\mu$M for $Fe^{3+}$. The area under concentration (AUC) can be obtained by the above analytical condition. In addition, to compare the stability of $Fe^{2+}$ to that of $Fe^{3+}$ in pharamaceutical preparations, accelerated stability test was carried out. After storing the samples under $40^{\circ}C$, 75%RH in light-resistant container for various time intervals, the contents of iron of different valencies were determined separately by the IC technique and the change and/or the interchange of among those iron species in preparations was investigated. Iron raw materials are stable, but $Fe^{2+}$ in$Fe^{3+}$ source materials was slightly converted to $Fe^{3+}$ by oxidation. $Fe^{2+}$ in$Fe^{3+}$ source raw materials and $Fe^{3+}$ in $Fe^{2+}$ raw materials are determined as impurities. Therefore, IC technique is found to be an appropriate method for comparative evaluation of dissimilar bioavailability of $Fe^{2+}$ and $Fe^{3+}$, stability of $Fe^{2+}$ and $Fe^{3+}$ raw materials and preparations.

• Tribology and Lubricants
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• v.35 no.4
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• pp.222-228
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• 2019

As rubber products such as O-rings, which are also known as packings or toric joints, come in regular, long term contact with liquid fuel, they can eventually swell, become mechanically weakened, and occasionally crack; this diminishes both their usefulness and intrinsic lifetime and could cause leaks during the steady-state flow condition of the fuel. In this study, we evaluate the lifetime of such products through compression set tests of FKM, a family of fluorocarbon elastomer materials defined by the ASTM international standard D141; these materials have great compression, sunlight, and ozone resistance as well as a low gas absorption rate. In this process, O-rings are immersed in the liquid fuel of airtight containers that can be expressed as a compression set, and the liquid fuel leakage in a flow rig tester at variable temperatures over 12 months is investigated. Using the Power Law model, our study determined a theoretical O-ring lifetime of 2,647 years, i.e. a semi-permanent lifespan, by confirming the absence of liquid fuel leakage around the O-ring assembled fittings. These results indicate that the FKM O-rings are significantly compatible for fuel tests to evaluate long-term sealing conditions.

• Journal of Periodontal and Implant Science
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• v.48 no.6
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• pp.337-346
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• 2018

Purpose: Peripheral artery disease (PAD) is a form of arteriosclerosis that occurs in the extremities and involves ischemia. Previous studies have reported that patients with periodontitis are at high risk for PAD. However, the relationship between these 2 diseases has not yet been fully elucidated. In this cross-sectional study, we investigated this relationship by comparing patients with PAD to those with arrhythmia (ARR) as a control group. Methods: A large-scale survey was conducted of patients with cardiovascular disease who visited Tokyo Medical and Dental University Hospital. We investigated their oral condition and dental clinical measurements, including probing pocket depth, bleeding on probing, clinical attachment level, and number of missing teeth; we also collected salivary and subgingival plaque samples and peripheral blood samples. All patients with PAD were extracted from the whole population (n=25), and a matching number of patients with ARR were extracted (n=25). Simultaneously, ARR patients were matched to PAD patients in terms of age, gender, prevalence of diabetes, hypertension, dyslipidemia, obesity, and the smoking rate (n=25 in both groups). Real-time polymerase chain reaction was performed to measure the bacterial counts, while the enzyme-linked immunosorbent assay method was used to measure anti-bacterial antibody titers and proinflammatory cytokine levels in serum. Results: PAD patients had more missing teeth ($18.4{\pm}2.0$) and higher serum levels of C-reactive protein ($1.57{\pm}0.85mg/dL$) and tumor necrosis factor-alpha ($70.3{\pm}5.7pg/mL$) than ARR patients ($12.0{\pm}1.7$, $0.38{\pm}0.21mg/dL$, and $39.3{\pm}4.5pg/mL$, respectively). Meanwhile, no statistically significant differences were found in other dental clinical measurements, bacterial antibody titers, or bacterial counts between the 2 groups. Conclusions: Our findings suggested that PAD patients had poorer oral and periodontal state with enhanced systemic inflammation.

• Korean Journal of Metals and Materials
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• v.49 no.3
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• pp.221-230
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• 2011

The cold spray process is an emerging technology that utilizes high velocity metallic particles for surface coating. Metallic powder particles are injected into a converging-diverging de Laval nozzle and accelerated to a high velocity by a supersonic gas flow. The cold spray process normally uses a circular nozzle that has a rather narrow spraying range. To overcome this fault, a slit nozzle was considered in this study. The slit nozzle is anticipated to reduce the coating process time because it has a wider coating width than the circular nozzle. However, the slit nozzle can reduce the coating efficiency because it does not allow as much gas and particle velocity as the circular nozzle. To improve the coating efficiency of a slit nozzle, the shape of the slit nozzle was modified. And the results of gas flow and particle behaviour according to the nozzlers shape were compared by the a numerical analysis. As a results, as Expansion Ratio(ER) of 7.5 was found to be the most optimal condition for enhancing the spraying efficiency when the ER was changed by the variation of nozzle neck and exit size.

• Journal of Auto-vehicle Safety Association
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• v.13 no.2
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• pp.30-34
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• 2021

Electrical failures and reliability problems of electronic components by ionic migration between adjacent device terminals have become an issue in automotive electronics. Especially unlike galvanic corrosion, ionic migration is occurred at high temperature and high humidity under applied electric field condition. Until now, although extensive studies of the ionic migrations dealing with PCBs, electrodes, and solders were reported, there is no study on the effect of insulation polymers and metallic fillers for ionic migration. In this research, therefore, ionic migration induced by the types and contents of polymers and metallic fillers, and variety conditions of temperature, humidity, and applied voltage was studied in detail. Ester and amide types of liquid crystal polymer (LCP) and poly (phthalamide) (PPA) were used as base polymers, respectively and compounded with the metallic fillers of Copper iodide (CuI), Zinc stearate (Zn-st), or Calcium stearate (Ca-st) in various compositions. The compounding polymers were fabricated in IPC-B-24 of SIR test coupon according to ISO 9455-17 with Cu electrodes for ionic migration test. While there is no change in LCP-based samples, ionic migration in PPA compounding sample with a high water absorption property was accelerated in the presence of 0.25 wt% or above of CuI at the environmental conditions of 85℃, 85% RH and 48V. The dendritic short-circuit growth of Cu caused by ionic migration between the electrodes on the surface of compounded polymers was systematically observed and analyzed by using optical microscopy and SEM (EDX).

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.1972-1981
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• 2022

A typical ferritic/martensitic (F/M) steel sheet was subjected to pulsed laser surface remelting (LSR) and corrosion test in lead-bismuth eutectic (LBE) at 550 ℃. There present two modification zones with distinct microstructures in the LSRed specimen: (1) remelted zone (RZ) consisting of both bulk δ-ferrite grains and martensitic plates and (2) heat-affected zone (HAZ) below the RZ, mainly composed of martensitic plates and high-density precipitates. Martensitic transformation occurs in both the RZ and the HAZ with the Kurdjumov-Sachs and Nishiyama-Wassermann orientation relationships followed concurrently, resulting in scattered orientations and specific misorientation characteristics. Hardnesses of the RZ and the HAZ are 364 ± 7 HV and 451 ± 15 HV, respectively, considerably higher than that of the matrix (267 ± 3 HV). In oxygen-saturated and oxygen-depleted LBE, thicknesses of oxide layers developed on both the as-received and the LSRed specimens increase with prolonging corrosion time (oxide layers always thinner under the oxygen-depleted condition). The corrosion resistance of the LSRed F/M steel in oxygen-saturated LBE is improved, which can be attributed to the grain-refinement accelerated formation of dense Fe-Cr spinel. In oxygen-depleted LBE, the growth of oxide layers is very low with both types of specimens showing similar corrosion resistance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.1
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• pp.188-210
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• 2022

As a promising technique to support tremendous numbers of Internet of Things devices and a variety of applications efficiently, mobile edge computing (MEC) has attracted extensive studies recently. In this paper, we consider a MEC-assisted peer-to-peer (P2P) mobile communication system where MEC servers are deployed at access points to accelerate the communication process between mobile terminals. To capture the tradeoff between the time delay and the energy consumption of the system, a cost function is introduced to facilitate the optimization of the computation and communication resources. The formulated optimization problem is non-convex and is tackled by an iterative block coordinate descent algorithm that decouples the original optimization problem into two subproblems and alternately optimizes the computation and communication resources. Moreover, the MEC-assisted P2P communication system is compared with the conventional P2P communication system, then a condition is provided in closed-form expression when the MEC-assisted P2P communication system performs better. Simulation results show that the advantage of this system is enhanced when the computing capability of the receiver increases whereas it is reduced when the computing capability of the transmitter increases. In addition, the performance of this system is significantly improved when the signal-to-noise ratio of hop-1 exceeds that of hop-2.