• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.3
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• pp.56-63
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• 1999

In this paper, we realize the active PFC(Power Factor Correction) system of BF (Boost Forward) converter with PWM-PFM control technique to control DC output voltage, and to control the input current with sinusoidal wave synchronized by the converter and inverter using power switching element, FET and IGBT. The control circuit of the suggested Boost converter is implemented with a microprocessor 80C196. After making the ratio of output voltage to current as 50V/1A and the duty ratio greater than 0.5. When input voltage is 30V and boost inductance is 1.1mH. We control the voltage changing rate according to the variation of load resistance using a PWM-PFM control technique. And finally we prove experimentally. PF can be improved up to 0.96 using the current shaping technique.

• New & Renewable Energy
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• v.2 no.3
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• pp.31-36
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• 2006

Superstrate pin amorphous silicon thin-film(a-Si:H) solar cells are prepared on $SnO_2:F$ and ZnO:Al transparent conducting oxides(TCO) in order to see the effect of TCO/p-layers on a-Si:H solar cell operation. The solar cells prepared on textured ZnO:Al have higher open circuit voltage VOC than cells prepared on $SnO_2:F$. Presence of thin microcrystalline p-type silicon layer(${\mu}c-Si:H$) between ZnO:Al and p a-SiC:H plays a major role by causing improvement in fill factor as well as $V_{OC}$ of a-Si:H solar cells prepared on ZnO:Al TCO. Without any treatment of pi interface, we could obtain high $V_{OC}$ of 994mV while keeping fill factor(72.7%) and short circuit current density $J_{SC}$ at the same level as for the cells on $SnO_2:F$ TCO. This high $V_{OC}$ value can be attributed to modification in the current transport in this region due to creation of a potential barrier.

• Steel and Composite Structures
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• v.21 no.3
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• pp.573-588
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• 2016

Carbon Fiber Reinforced Plastic (CFRP) and Titanium Alloy (Ti6Al4V) stack, extensively used in aerospace structural components are assembled by fasteners and the holes are made using drilling process. Drilling of stack in one shot is a complicated process due to dissimilarity in the material properties. It is vital to have optimal machining condition and tool geometry for better hole quality and tool life. In this study the tool wear and hole quality were analysed by experimental analysis using three modified twist drills and online tool condition monitoring using Acoustics Emission (AE) sensor. Helix angle and point angle influence tool performance and cutting force. It was found that a tool geometry (TG1) with high helix angle of $35^{\circ}$ with low point angle $130^{\circ}$ results in reduction in thrust force of 150-500 N range but the TG2 also perform almost similar to TG1, but when compared with the AErms voltage generated during drilling it was found that progressive rise in voltage in TG1 is less with respect to TG2 which can be attributed to tool life. In process wear monitoring was done using crest factor as monitoring index. AErms voltage were measured and correlated with the performance of the drills.

• KSBB Journal
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• v.6 no.1
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• pp.35-43
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• 1991

The production of poly-$\beta$-hydroxybutyrate(PHB) from methanol by batch and fed-batch cultivations of Methylobacterium sp. GL-10 was studied. PHB accumulation was stimulated by the nutrients deficiency including, NH4+, SO42-, and K+. The nitrogen deficiency was the most critical factor for PHB accumulation. In batch cultivation, the maximum cell concentration and PHB content were 1.86g/l and 0.62g/l, respectively, with 1.0%(v/v) of methanol and 0.5g/1 of ammonium sulfate. The mass doubling time of Methylobacterum sp. GL-10 was in the range of 4-5 hrs. The cell growth and PHB accumulation were severely inhibited at the methanol concentration over than 2% (v/v). To overcome methanol Inhibition, constant feeding and intermittent feedillg fed-batch cultivations were adopted, using C/N molar ratio as a control factor. In constant feeding fed-batch process, cell concentration was increased up to 2.67g/1, and PHB yield was enhanced from 0.33 of batch culture to 0.53. The relatively low cell concentration was caused by methanol accumulated in culture broth at late growth phase. To prevent methanol accumulation and to maximize PHB production, DO-state intermittent fed-batch cultivation was attempted. The cell and PHB concentration was reached up to 4.55g/1 and 1.80g/1, respectively. It was possible to maintain methanol concentration low and also to feed nutrient of desired C/N molar ratio.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.536-538
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• 2018

This paper introduces an enhanced interleaved (IL) PFC (Power Factor Correction) boost converter typed 650V Intelligent Power Module (IPM), which is fully optimized hybrid IGBT converter modules; Silicon (Si) IGBT and Silicon Carbide (SiC) diode, for up to 10kW HVAC (Heating, Ventilation, and Air Conditioning) systems. It utilizes newly developed $4^{th}$ Generation Field Stop (FS) trench IGBTs, $EXTREMEFAST^{TM}$ anti-paralleled diodes, SiC Junction Barrier Schottky (JBS) diodes, Bridge rectifiers, Multi-function LVIC, and Built-in thermistor provide good reliable characteristics for the entire system. This module also takes technical advantage of DBC (Direct Bonded Copper) substrate for the better thermal performance. It is shown that the Si IGBT/SiC diode hybrid IL PFC module can achieve excellent EMI performance and greatly enhance the power handling capability or switching frequency of various applications compared to the Si IGBT/Diode. This paper provides an overall description of the newly developed 650V/50A Hybrid SiC IL PFC IPM product.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.4
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• pp.259-265
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• 2010

The proposed method offers an improved control method for high power density AC/DC adapter by using more energy efficient electrical equipments. Power factor corrector (PFC) topology is based on boost topology with boundary conduction mode (BCM) and DC/DC topology is based on LLC resonant converter, which helps to reduce size of the semiconductor and the magnetic devices. Test results with 85W AC/DC adapter (18.5V/4.6A) design shows that the measured efficiency is 90% at $90V_{rms}$ input voltage with power density of $36W/in^3$. It also shows low no load power consumption of about 0.5W.

• The Korean Journal of Applied Statistics
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• v.28 no.5
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• pp.951-963
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• 2015

The conjoint analyst in marketing are anxious to know whether there exist synergy or antagonistic effects between two attributes. That is to say, they are interested in estimating the main effects as well as the two factor interaction effects.We research the design of survey questionnaire so that all the main effects and two factor interaction effects are estimable by employing the resolution V balanced Incomplete Block Fractional Factorial Design. We screen vital few effects, find the proper model and obtain information for efficient concepts optimization by analyzing all respondents survey data.

• BMB Reports
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• v.45 no.10
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• pp.554-559
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• 2012

Oligosaccharide modification by N-acetylglucosaminyltransferase-V (GnT-V), a glycosyltransferase encoded by the Mgat5 gene that catalyzes the formation of ${\beta}1$,6GlcNAc (N-acetylglucosamine) branches on N-glycans, is thought to be associated with cancer growth and metastasis. Overexpression of GnT-V in cancer cells enhances the signaling of growth factors such as epidermal growth factor by increasing galectin-3 binding to polylactosamine structures on receptor N-glycans. In contrast, GnT-V deficient mice are born healthy and lack ${\beta}1$,6GlcNAc branches on N-glycans, but develop immunological disorders due to T-cell dysfunction at 12-20 months of age. We have developed Mgat5 transgenic (Tg) mice (GnT-V Tg mice) using a ${\beta}$-actin promoter and found characteristic phenotypes in skin, liver, and T cells in the mice. Although the GnT-V Tg mice do not develop spontaneous cancers in any organs, there are differences in the response to external stimuli between wild-type and GnT-V Tg mice. These changes are similar to those seen in cancer progression but are unexpected in some aspects. In this review, we summarize what is known about GnT-V functions in skin and liver cells as a means to understand the physiological roles of GnT-V in mice.

• Journal of Information Technology Services
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• v.11 no.sup
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• pp.51-60
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• 2012

In this paper, we provide the analysis of device model and method between device models for compatible M&S V&V of the NetSPIN. First of all, we analysis features, structure, and classification of the NetSPIN. The second, as a part of reliable V&V process, we analysis network system modeling process, correlation between device modeling process for M&S of the NetSPIN. The third, we suggest making a kind of pool of reference model and module of devices for the increase factor of reuse between device model. We also, at the point view of M&S V&V, conclude that there is the validity of the fidelity in device modeling process. Through the analysis of the NetSPIN device model and suggestion of the method for higher compatibility between device modes, the development process of device model be clearly understood. Also we present the effective method of the development for reliable device mode as the point of V&V.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.135-140
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• 1997

A highly efficient single-phase/three-phase compatible ac-to-dc converter is proposed and analyzed, which includes three identical single-phase both soft-switched dc-to-dc converter with boost converter as a pre-regulator for input power factor correction (PFC). The proposed converter structure provides a cost reduction and easy implementation of compatibility between single-phase 220V and three-phase 220V/380V with their inputs in delta or wye connections.