• ETRI Journal
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• v.37 no.6
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• pp.1154-1164
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• 2015

This paper proposes a fully sensorless driver for a permanent magnet synchronous motor (PMSM) integrated with a digital motor controller and an analog pre-driver, including sensing circuits and estimators. In the motor controller, a position estimator estimates the back electromotive force and rotor position using a sliding-mode observer. In the pre-driver, drivers for the power devices are designed with a level shifter and isolation technique. In addition, a current sensing circuit measures a three-phase current. All of these circuits are integrated in a single chip such that the driver achieves control of the speed with high accuracy. Using an IC fabricated using a $0.18{\mu}m$ BCDMOS process, the performance was verified experimentally. The driver showed stable operation in spite of the variation in speed and load, a similar efficiency near 1% compared to a commercial driver, a low speed error of about 0.1%, and therefore good performance for the PMSM drive.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.171-178
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• 2006

The performance in the practical combustion system including reciprocating engines and gas turbine combustors is being much governed by turbulent reacting flow that is often analyzed by both a laminar flamelets concept and flame interaction. The characteristics of laminar flame interaction have been investigated numerically to provide basic understanding of wrinkled turbulent flames under concentration interaction resulting from inhomogeneity in fuel-air mixing, especially focused on the transition of flame characteristics such as diffusion flame, partially premixed diffusion flame, and triple-layer flame by the variation in the degree of premixedness. The extinction stretch rates to the premixedness have also been obtained in this paper. The boundary defining the regime of the existence of triple-layer flames as functions of both stretch rate and premixedness has been determined which agrees well with previously reported experiment measuring OH radical concentration peaks based on PLIF.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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• pp.176-180
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• 2007

Five liglans, sauchinone (1), di-0-methyltetrahydrofuriguaiacin B (2), manassantin A (3), manassantin B (4) and saucerneol B (5), have been isolated from the MeOH extract of Saururus chinesis roots. The evaluation for protective effect of compounds 1-5 against tacrine-induced cytotoxicity in human liver-derived Hep G2 cells was conducted. Compounds 1,2, and 5 showed significant protective effects with the EC$_{50}$ values of74.2${\pm}$0.9, 111.3${\pm}$0.8,64.3${\pm}$0.8 ${\mu}$M, respectively. Silybin, one of the well-known hepatoprotective agents, used as a positive control, and also showed protective effect with an EC$_{50}$ value of 86.2${\pm}$0.5 ${\mu}$M.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.388-396
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• 2011

The strengthened regulations for atmospheric emissions from ships have caused a necessity of new, alternative power system in ships for the low pollutant emissions and the high energy efficiency. Recently, new kinds of propulsion power system such as fuel cell system, which use hydrogen as an energy source, have been sincerely considered. Fuel conversion system to hydrogen is an essential part for fuel cell ship. We have investigated thermodynamically the steam reforming characteristics of hydrocarbons and alcohols for the fuel conversion systems.

• Analytical Science and Technology
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• v.5 no.1
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• pp.51-56
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• 1992

A method to determine the trace level of arsenic in scalp hair by the hydride generation(HG)-inductively coupled plasma(ICP) spectrometry is described. The optimum conditions for the generation of arsine($AsH_3$), and the interference effects from the concomitant ions were studied. Severe interference effect from Ni(II) is circumvented by the coprecipitation of arsenic with $La(OH)_3$. The detection limit of arsenic is 0.3ppm and the arsenic contents in scalp hair ranged 10~20ppb.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.4
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• pp.448-454
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• 2010

The strengthened regulations for atmospheric emissions from ships have caused a necessity of new, alternative power system in ships for the low pollutant emissions and the high energy efficiency. Recently, new kinds of propulsion power system such as fuel cell system, which use hydrogen as an energy source, have been sincerely considered. The purpose of this work is to predict the performance of methanol fueled SOFC system and to analyze the influence of operating temperature, current density, S/C, and $H_2$ utilization ratio.

• YAKHAK HOEJI
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• v.36 no.2
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• pp.115-119
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• 1992

The possibility as an anti-inflammatory drug of Prunus davidiana which have been used in Korean folk medicine for treatment of neuritis and rheumatism was investigated on carrageenin-induced paw edema in rats. The MeOH extract exhibited potent inhibitory effect on carrageenin-edema rats when topically applicated. On the other hand, it did not show any effect when orally tested. It also had no influences on isolated ileum of guinea pig and anti-platelet aggregating activities. Thus, it appears from the present findings that the MeOH extract of P. davidiana may be utilizable only for the external treatment of inflammed sites. This study was also conducted to further isolation of flavonoids from the EtOAc soluble fraction and characterized as persiconin and isosakuranin by spectrometric analysis.

• Natural Product Sciences
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• v.13 no.3
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• pp.263-267
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• 2007

The mast cell-mediated immediate-type allergic reaction is involved in many allergic diseases such as asthma, allergic rhinitis, and sinusitis. The discovery of drugs for the treatment of mast cell-mediated immediate-type allergic diseases is a very important subject in human health. In this study, we investigated the effect of small black soybean (Glycine max Merr.) (Leguminosae) on mast cell-mediated allergic reaction and pro-inflammatory cytokine secretion. Small black soybean (SBS) inhibited compound 48/80-induced systemic reaction. SBS attenuated immunoglobulin (Ig) E-mediated local allergic reaction. In addition, SBS decreased the phorbol 12-myristate 13-acetate plus calcium ionophore A23187-stimulated tumor necrosis factor $(TNF)-{\alpha}$ and interleukin (IL)-8 secretion in human mast cells. These results indicate that SBS may be beneficial in the treatment of mast cell-mediated immediate-type allergic reactions.

• Archives of Plastic Surgery
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• v.36 no.6
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• pp.702-706
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• 2009

Purpose: Analysis of lower nose and upper lip asymmetry in patients with unilateral cleft lip nose deformity has been proceeded through direct measurement and photo analysis. But there are limitation in presenting real image because of its 2 dimensional trait. The authors analyzed such an asymmetry using 3D VECTRA system (Canfield, NJ, USA) in quantitative way. Methods: In 25 Patients with unilateral cleft lip nose deformity(male 12, female 13, age ranging from 4 to 19), patients with right side deformity were 10 and left were 15. Analysis of asymmetry was proceeded through 3D VECTRA system. After taking 3 dimensional photo, alar area, upper lip area, nostril perimeter, nostril area, Cupid's bow length, nostril height and nostril width were measured. Correlation coefficient and inter data quotients were calculated. Results: In nostril perimeter, maximal difference of cleft side and non - cleft side was 39.3%, asymmetric quotient Qasy = Qcl/Qncl(Qcl, value of cleft side; Qncl, value of non - cleft side) was ranged from 0.84 to 1.85 and in seven cases the length of cleft side was smaller. In nostril area, maximal difference was 69.6% and in 13 cases cleft side was smaller. In lower nasal area, maximal difference was 37.2% asymmetric quotient Qasy = Qcl/Qncl was ranged from 0.47 to 2.03 and in 20 cases cleft side was smaller. The correlation coefficients of nostril perimeter and area were 0.8345. Conclusion: Using 3D VECTRA system, the authors can measure nostril perimeter and lower nasal area that could not been measured with previous methods. Asymmetry of midface was analyzed through area comparison in quantitative way. Futhermore, post operative change can be measured in quantitative method.

• Culinary science and hospitality research
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• v.20 no.5
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• pp.59-66
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• 2014

The purpose of this study is to analyze the level of career development competency recognized by the specialists who major in food service currently. To achieve the purpose of this study, the five two-year-courses technical colleges in Kyeonggi-do, Daejeon, Daegu Metropolitan City which include food service department were selected. And total 280 samples of enrolled students were extracted and the 256 students were treated statistically besides the 24 students who responded dishonestly. The analysis results are as follows. First, the male students showed partially higher career development competencies than female students. Second, the second grade students showed partially higher career development competency than the first grade students. Third, the specialists whose family income is over 5 million won showed the highest career development competency, and the students in 3-5 million won and less than 3 million won followed them in order. Fourth, there were differences in competencies of lifelong learning, networking, collecting and utilizing the job information, and self-understanding, and career transition, and the specialists with more qualifications showed higher competency than those who with less qualifications. Therefore, it is necessary to develop a various career education program to enhance career development competencies of food service specialist by individual characteristic.