• Journal of international Conference on Electrical Machines and Systems
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• 제2권2호
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• pp.225-231
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• 2013

Low voltage ride through capability augmentation of a hybrid micro-grid system is presented in this paper which reflects enhanced reliability in the system. The control scheme involves parallel connected multiple ac-dc bidirectional converters. When the micro-grid system is subjected to a severe voltage dip by any transient fault single power converter may not be able to provide necessary reactive power to overcome the severe voltage dip. This paper discusses the control strategy of additional power converter connected in parallel with main converter to support extra reactive power to withstand the severe voltage dip. During transient fault, when the terminal voltage crosses 90% of its pre-fault value, additional converter comes into operation. With the help of additional power converter, the micro-grid system withstands the severe voltage fulfilling the grid code requirements. This multiple converter scheme provides the micro-grid system the capability of low voltage ride through which makes the system more reliable and stable.

• Corrosion Science and Technology
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• 제9권6호
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• pp.247-253
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• 2010

The characteristics of selective oxidation prior to hot-dip galvanizing with the annealing atmosphere dew point and chemical composition in dual-phase steels and their effect on the inhibition layer formation relevant to coating adhesion have been studied using a combination of electron microscopic and surface analytical techniques. The annealed and also galvanized samples of 3 kinds of Si/Mn ratios with varied amounts of Si addition were prepared by galvanizing simulator. The dew point was controlled at soaking temperature $800^{\circ}C$ in 15%$H_2$ -85%$N_2$ atmosphere. It was shown that good adhesion factors were mainly uniformity of oxide particle distribution of low number density and low Si/Mn ratio prior to hot-dip galvanizing. Their effect was the greatly reduced coating bare spots and the formation of uniform inhibition layer leading to good adhesion of Zn overlay. The mechanism of good adhesion is suggested by two processes: the formation of inhibition layer on the oxide free surface uncovered with no $SiO_2$-containing particles in particular, and the inhibition layer bridging of oxide particles. The growth of inhibition layer was enhanced markedly by the delayed reaction of Fe and Al with the increase of Si/Mn ratio.

• 천문학논총
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• 제30권2호
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• pp.593-594
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• 2015

We present our analysis results for an updated orbital ephemeris for the dipping low mass X-ray binary 4U 1624-49, using the light curve collected by the All Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer (RXTE) and the Monitor of All-Sky X-ray Image (MAXI). To make clear dip profiles, the light curve from the ASM and the MAXI were divided into ten 500d segments and four 400d segments for ASM and MAXI light curves, respectively, and folded with the linear ephemeris proposed by Smale et al. (2001). The phases of dip centers were determined by the method adopted from Hu et al. (2008). The phase drift was then fitted with a linear function. We obtained an updated orbital period of 0.869896(1) d and a phase zero epoch of JD 2450088.6618(57). No clear orbital period derivative is detected with a 2-sigma upper limit of $1.4{\times}10^{-6}(yr)^{-1}$ from a quadratic curve fitting of the dip phase evolution.

• 조명전기설비학회논문지
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• 제17권4호
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• pp.8-12
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• 2003

TO-can 레이저 다이오드를 사용한 광송수신기 모듈의 주파수 대역의 특성을 관찰하였다. 레이저 다이오드의 등가회로를 추출하기 위한 R-L-C변수는 임피던스 분석기를 이용하였다. 칩콘덴서를 사용하여 패키지내의 도선에 의한 인덕턴스 성분과의 임피던스 정합을 시도하였으나 저주파수 대역에서 공진으로 인한 경사가 발견되었다. 표면실장 형으로 소자를 구성하여 사용함으로써 공진주파수를 이동시켜 원하는 주파수 대역에서 공진 경사를 제거할 수 있었다.

• Ocean Science Journal
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• 제40권4호
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• pp.183-190
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• 2005

We investigated the seasonal variability of tree alkaline phosphatase activity in seawater and alkaline phosphatase hydrolysable phosphorus (APHP) at 3 stations in Hiroshima Bay using alkaline phosphatase extracted from the dinoflagellates Alexandrium tamarense and Gymnodinium catenatum. The dissolved inorganic phosphorus (DIP) was lower than $1\;{\mu}M$ all samples; the lowest values were in May. The amount of APHP was high at the surface and bottom waters of all stations in May, showing DIP-depleted conditions. In August and November, the amount of APHP was much less than the amount of APHP in May, indicating that the availability of dissolved organic phosphorus (DOP) for these species was low and/or uptake during the dinoflagellate blooming might have occurred in the area. The results obtained from short-term variations of AP activity might suggest that the growth of dinoflagellates in this season may be partly supported by the AP produced by other diatoms.

• 한국토양비료학회지
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• 제50권6호
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• pp.615-622
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• 2017

This study was conducted to evaluate the odor reduction efficacy of the dip injection wet scrubber (DIWS) using tap water as washing fluid. The $NH_3$ and $H_2S$ removal efficiency of 7 day batch operated DIWS was evaluated twice over a total of 14 days of experiment. The $NH_3$ removal efficiency ranged from 26 to 37%. The $H_2S$ removal efficiency was between 22 and 30%. The pH of the washing fluid maintained below 8 and the $NH_4{^+}$ concentration tended to keep constant around 350 ppm after 5 days of washing-fluid replacement. Therefore, the 5-day washing fluid replacement interval is more preferable than the 7-day interval. The $NH_4{^+}$ concentration and the electrical conductivity (EC) showed a high correlation. The EC measurement can be used as an alternative to conventional $NH_4{^+}$ concentration measurement method for real time monitoring of washing fluid condition.

• 한국전기전자재료학회논문지
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• 제34권6호
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• pp.487-494
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• 2021

Piezoelectric generators use direct piezoelectric effects that convert mechanical energy into electrical energy. Many studies were attempted to fabricate piezoelectric generators using piezoelectrics such as ZnO, PZT, PVDF. However, these various inorganic/organic piezoelectric materials are not suitable for bio-implantable devices due to problems such as brittleness, toxicity, bio-incompatibility, bio-degradation. Thus, in this paper, piezoelectric generators were prepared using a silk fibroin film which is bio-compatible by dip-coating method. The silk fibroin films are a mixed state of silk I and silk II having stable β-sheet type structures and shows the d₃₃ value of 8~10 pC/N. There was a difference in output voltages according to the thickness. The silk fibroin generators, coated 10 times and 20 times, revealed the power density of 16.07 μW/cm² and 35.31 μW/cm² using pushing tester, respectively. The silk fibroin generators are sensitive to various pressure levels, which may arise from body motions such as finger tapping, foot pressing, wrist shaking, etc. The silk fibroin piezoelectric generators with bio-compatibility shows the applicability as a low-power implantable piezoelectric generator, healthcare monitoring service, and biotherapy devices.

• Corrosion Science and Technology
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• 제18권3호
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• pp.73-77
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• 2019

Hot-dip aluminized coating has been widely used to protect steel substrate against corrosion. In this study, the corrosion behavior of hot-dip aluminized type 409L (11% Cr) stainless steel (SS) was investigated using macro- and micro-scale polarization tests. An Al-Fe-Si alloy layer that was formed due to inter-diffusion of alloying elements between Al coating and SS substrate was observed between Al coating and 409L SS substrate. In both macro- and micro-scale polarization tests, the corrosion potential ($E_{corr}$) of the 409L SS substrate was much nobler than that of the Al coating and alloy layer. $E_{corr}$ of the alloy layer was between that of Al coating and 409L SS substrate. This indicates that the alloy layer can act as a buffer between the more active Al coating and the nobler SS substrate for pit growth in aluminized SS. The presence of the alloy layer appears to be helpful in hindering pitting corrosion of aluminized SS.

• Corrosion Science and Technology
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• 제20권6호
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• pp.384-390
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• 2021

In this paper, durability evaluation and surface damage mechanism were investigated through solid particle erosion (SPE) test after applying hot-dip aluminizing (HDA) technology for the purpose of maintenance of marine economizer tube. Damaged surface shape was analyzed using SEM and 3D microscope. Compositional changes and microstructure of the HDA layer were analyzed through EDS and XRD. Durability was evaluated by analyzing weight loss and surface damage depth after SPE. HDA was confirmed to have a two-layer structure of Al and Al₅Fe₂. HDA+HT was made into a single alloy layer of Al₅Fe₂ by diffusion treatment. In the microstructure of HDA+HT, void and crack defect were induced during the crystal phase transformation process. The SPE damage mechanism depends on material properties. Plastic deformation occurred in the substrate and HDA due to ductility, whereas weight loss due to brittleness occurred significantly in HDA+HT. As a result, the substrate and HDA showed better SPE resistance than HDA+HT.

• 유통과학연구
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• 제20권6호
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• pp.109-123
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• 2022

Purpose: This research presents a practical tool aimed at increasing collaboration between designers and marketers for effective retail space branding. We present a design-related information processing model (DIP Model), which is a schematic map that includes cognitive theories which have design applications to retail space branding. Research design, data and methodology: Through literature review and practitioner opinion survey, 43 theories pertaining to the brand communication in retail spaces were selected, and design applications of the theories were analysed through field trips to stores of global brands. Results: The DIP Model consists of two axes: the information processing axis (i.e., encoding vsretrieval) and the regulatory focus axis(i.e., promotion vs prevention). Theories related to information processing axis are theories that facilitate the encoding and retrieval of information as intended by the company. Theories related to regulatory focus axis are theories that reinforce positive cognition and prevent negative cognition regarding the brand. Conclusions: The DIP Model is developed as a tool to categorise cognitive theories that are applicable to the design of brand communication in retail spaces. As such, the model can provide a better understanding of the role of behavioural design, with the aim of building stronger brands in retail spaces.