• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.4
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• pp.118-124
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• 2010

We proposed a goods load simulator for optimum RFID distribution, which includes experiment process modeling guidelines for stable RFID scan rate, efficient cost-reduction of RFID application or even speedy management of RFID field. We show verification of this simulator using field test of distribution, and the proposed simulator has better performance than the classic method, and demonstrate the proposed is efficient method of draw up guidelines on RFID distribution.

• Corrosion Science and Technology
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• v.3 no.4
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• pp.154-160
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• 2004

The Sulfide Stress Corrosion Cracking (SSCC) resistance of structural steels is one of the critical concerns for the operators, material designers, and fabricators of oil-field equipment, especially treating sour gas (H2S) containing fluids. As far as its fabricators concerned, the systematic care of welding parameters should be taken to obtain comparable SSCC resistance of their weldment to that of its base material. In this respect, every different type of welding joint design for this use should be verified to be SSCC-proof with relevant test procedures. In this study, the welding parameters to secure a proper SSCC resistance of steel pipe's weldments were reviewed on the Welding Procedure Qualification Records (WPQR), which had been employed for actual fabrication of an offshore structure for oil and gas production. Based on this review, a guideline of welding parameters, such as, heat input, welding consumable for Y.S. 65 ksi class steel pipe material is proposed in terms of the NACE criteria for SSCC resistance.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.4
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• pp.253-261
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• 2021

This paper describes the process of evaluating maneuverability in still water of an unmanned surface vehicle based on data measured by performing sea trials. First, we set up a test scenario that is easy to analyze the maneuverability of the unmanned surface vehicle and to identify and verify the dynamics model. Since the attitude of hull varies according to the speed of the unmanned surface vehicle which has a planing hull shape, the relationship between waterjet RPM, speed and attitude is analyzed by performing straight forward tests at various speeds. The turning tests of the unmanned surface vehicle in which the waterjet angle rotates while turning are performed by changing the waterjet rotation angle under the condition of two representative speeds to analyze turning ability. The turning ability of the unmanned surface vehicle includes speed reduction, yaw rate, heel, and turing diameter at steady turning phase according to the speed and RPM.

• Journal of Animal Environmental Science
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• v.19 no.1
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• pp.39-46
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• 2013

This study was carried out to compare the filtration effect of anaerobic digestion waste water by compost filtration bed. Three types of filtration systems were set for filtration test following to composition of bedding materials. Two filtration systems were filled with sawdust, rice-hull and wood-chip. And the other was filled with sawdust and rice-hull. Anaerobic digestion waste water was applied evenly on the surface of the filtration bed with spraying nozzle. The concentration of nitrogen, biochemical oxygen demand (BOD), suspended solids (SS) of anaerobic digestion waste water was decreased by filtration treatment. The total nitrogen content was decreased from 1,313 mg/L to 1,090~1,293 mg/L and BOD concentration was decreased from 529.7 mg/L to 125~162.3 mg/L, respectively. The SS content was decreased from 69~79% by filtration process. In addition, the electrical conductivity (EC) was decreased from 10.22 ds/m to 7.91~8.31 ds/m.

• Proceedings of the SCSK Conference
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• 1999.10a
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• pp.111-121
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• 1999

Acne vulgaris, the most common skin disease. can be formed as only a few comedons or severe inflammatory lesions. The pathogenesis of acne involves various factors; excessive androgen, excessive sebum production, abnormal alteration of follicular epithelium, proliferation of Propionibacterium acnes, and inflammation. We investigated acne therapy using oriental herbs described in the Korean traditional medical book (Dong-ui-bo-gam). Oriental herbs (Angleica daurica. Arctium lappa. Coptidis rhizoma, and glycyrrhiza glabra) were chosen based on their respective property of sebum control, anti-inflammatory activity, and anti-bacterial activity. We examined the effect of acne treatment, in terms of chemotactic inhibition, lipogenesis inhibition, and anti-bacterial activity for P. acnes. 1. Neutrophil chemotaxis assay ; P acnes secrete chemotactic factors and other pro-inflammatory extracellular products. Neutrophil chemotactic activity of P. acnes was measured by 48-well chemotaxis method. Angelica daurica clearly suppressed chemotactic activity of P. acens. 2. Using sebaceous gland of hamster ear lipogenesis assay; Sebaceous lipogenesis was measured using ear biopsies by incubation of $C^{14}$ -acetate in culture media. The $C^{14}$ -labeled lipids were extracted and determined by liquid scintilation counting, Coptidis rhizoma markedly inhibited sebum production, 3. Anti-bacterial assay for P. acnes (MIC test) Glycyrrhiza glabra showed anti-bacterial activity. P. acnes did not develop resistance against Glycyrrhiza glabra. Retinoids are effectively to inhibit sebum production and regulate follicular keratinization process, with little anti-inflammatory activity. Angelica daurica suppressed neutrophil chemotaxis. Coptidis rhizoma inhibited sebum production, and Glycyrrhiza glabra showed anti-bacterial activity against P. acnes. A combined formulation of Angelica daurica. Coptidisr hizoma and Glycyrrhiza glabra is expected to provide effective acne treatment.ent.ive acne treatment.

• Tunnel and Underground Space
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• v.22 no.4
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• pp.257-265
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• 2012

In this study, a series of CFD (Computational Fluid Dynamics) simulations carried out to evaluate the optimum design model of the internal flow path of drill bit. The Star-CCM+ code was adopted to simulate the multi-phase discharge flow of rock particles and flushing air during a drilling process. The input parameters for the flow simulation of rock particles and air were obtained from the in-situ drilling test results. After the three design factors were determined, the experimental design method (Taguchi method) was utilized to evaluate the optimum value of each factor.

• Corrosion Science and Technology
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• v.22 no.6
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• pp.447-456
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• 2023

In this work, we performed a comparative study examining two coatings on Ti Gr.1 for use in fuel cell bipolar plates. The coatings consisted of carbon black as the conductor along with acrylic polymer and Ti Sol-Gel binder as the binder. Ti Sol-Gel that had precipitated as TiO₂ in areas impregnated between carbon black gaps, thereby acting as a binder for carbon black and serving as a polymer coating. Neither of the coatings peeled off during the 90° bend test to check formability. The contact resistance of the TiO₂ coating was found to be lower than that of the polymer binder coating. Moreover, due to coating shrinkage (denser) that occurred during the heat treatment process, the TiO₂ binder coating showed almost the same level of corrosion resistance, as measured by potentiostatic and EIS tests, despite being thinner than the polymer coating. However, both the polymer binder coating and the TiO₂ binder coating had many pores and irregularities internally (around 10 ~ 100 nm) and on the surface (0.1 ~ 2 ㎛). We considered that these pores and irregularities contributed to the lower corrosion resistance.

• Journal of the Korean Society for Heat Treatment
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• v.24 no.3
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• pp.127-132
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• 2011

The silicon-containing Diamond-like Carbon (Si-DLC) film as an low friction coefficient coating has especially treated a different silicon content by plasma-enhanced chemical vapor deposition (PECVD) process at $500^{\circ}C$ on nitrided-STD 11 mold steel with (TMS) gas flow rate. The effects of variable silicon content on the Si-DLC films were tested with relative humidity of 5, 30 and 85% using a ball-on-disk tribometer. The wear-tested and original surface of Si-DLC films were analysed for an understanding of physical and chemical characterization, including a changing structure, via Raman spectra and nano hardness test. The results of Raman spectra have inferred a changing intra-structure from dangling bonds. And high silicon containing DLC films have shown increasing carbon peak ratio ($I_D/I_G$) values and G-peak values. In particular, the tribological tested surface of Si-DLC was shown the increasing hardness value in proportional to TMS gas flow rate. Therefore, at same time, the structure of the Si-DLC film was changed to a different intra-structure and increased hardness film with mechanical shear force and chemical reaction.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.633-641
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• 2021

The study performed long-term performacne evaluation on the hot mix asphalt using the steel slag aggregates and Reclaimed Asphalt Pavement (RAP). The laboratory comparative evaluation was conducted between conventional Hot Mix Asphalt (HMA) which is entitled WC-2 and HMA containing steel slag and RAP which is entitled ES WC-2(R). Dynamic stability test, dynamic modulus test, and fatigue crack test were conducted during the comparative evaluation process. The dynamic stability test result showed that ES WC-2(R) was 140% higher than WC-2. It is noted that ES WC-2(R) showed no inflection point whereas WC-2 showed inflection point during the dynamic stability test which implies ES WC-2(R) has the higher moisture susceptability than WC-2. The dynamic modulus of ES WC-2(R) were 342.3%, 486.7%, and 350.0% higher than WC-2 at medium temperature of 21℃, low temperature of -10℃, and high temperature of 38℃ respectively. The test result showed that rutting resistance of ES WC-2(R) is higher than WC-2 at all temperature spectrum. The fatigue resistance of ES WC-2(R) were 31.7%, 325.3%, 899.9% higher at low stress level, medium stress level, and high stress level, respectively. The test result showed that ES WC-2(R) is higher than WC-2 at all stress levels. Based on the laboratory comparative evaluation, The in-situ scale Accelerated Pavement Test (APT) was conducted comparing WC-2 and WC-2(R). APT found that the rutting resistance of WC-2(R) was 45% higher than WC-2.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.54-70
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• 2017

The accumulator is a passive safety injection device for emergency core cooling systems. As an important safety feature for providing a high-speed injection flow to the core by compressed nitrogen gas pressure during a loss-of-coolant accident (LOCA), the accumulator injects its precharged nitrogen into the system after its coolant has been emptied. Attention has been drawn to the possible negative effects caused by such a nitrogen injection in passive safety nuclear power plants. Although some experimental work on the nitrogen injection has been done, there have been no comparative tests in which the effects on the system responses and the core safety have been clearly assessed. In this study, a new thermal hydraulic integral test facility-the advanced core-cooling mechanism experiment (ACME)-was designed and constructed to support the CAP1400 safety review. The ACME test facility was used to study the nitrogen injection effects on the system responses to the small break loss-of-coolant accident LOCA (SBLOCA) transient. Two comparison test groups-a 2-inch cold leg break and a double-ended direct-vessel-injection (DEDVI) line break-were conducted. Each group consists of a nitrogen injection test and a nitrogen isolation comparison test with the same break conditions. To assess the nitrogen injection effects, the experimental data that are representative of the system responses and the core safety were compared and analyzed. The results of the comparison show that the effects of nitrogen injection on system responses and core safety are significantly different between the 2-inch and DEDVI breaks. The mechanisms of the different effects on the transient were also investigated. The amount of nitrogen injected, along with its heat absorption, was likewise evaluated in order to assess its effect on the system depressurization process. The results of the comparison and analyses in this study are important for recognizing and understanding the potential negative effects on the passive core cooling performance caused by nitrogen injection during the SBLOCA transient.