• Journal of Magnetics
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• v.15 no.2
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• pp.78-84
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• 2010

A 3-D.O.F. spherical PM motor has 3 degrees of freedom in its motion by tilting and rotating of a shaft, which can be applied in a range of fields. The back-EMF is proportional to the field flux and angular velocity. The back-EMF constant in conventional rotating machine has a uniform value. However, in a spherical PM motor, the back-EMF constant of the coils varies according to the tilting conditions regardless of whether the angular speed is constant. Consideration of the back-EMF constant is useful for designing 3-D.O.F. spherical PM motors. In this study, the back-EMF constant of the spherical PM motor was considered carefully.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.9 s.100
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• pp.909-916
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• 2005

This paper describes that the Q factor of a conventional $\lambda$/4-microstrip resonator with short load can be improved and also the problem that the serial-resonant frequency(2$f_o$) should be deviated from can be settled by the proposed $\lambda$/4-microstrip resonator, which is used to suppress the harmonics of a nonlinear circuit.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.1
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• pp.1-9
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• 2007

In this paper, a third-order harmonic mixer is designed using frequency multiplier theory for the Ka-band. The gate bias voltage is selected by frequency multiplier theory to maximize the third-order harmonic element ofthe fundamental LO frequency in the proposed mixer. The designed mixer has a gate mixer structure composed of a gate terminal input for the fundamental local signal ($f_{LO}$), RF signal (${RF}$) and a drain terminal output for the harmonic frequency ($3f_{LO}-f_{RF}$) respectively. The Ka-band harmonic mixer is designed and fabricated using a commercial GaAs MESFET device with a plastic package. The proposed mixer will provide a solution for the problems found in the high cost, complex circuitry in a conventional Ka-band mixer. The 33.5 GHz harmonic mixer has a -10 dB conversion gain by pumping 11.5 GHz LO with a +5 dBm level.

• Journal of Magnetics
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• v.15 no.1
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• pp.36-39
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• 2010

The multi-degrees of freedom surface permanent-magnet motor (Multi-D.O.F. SPM) has several degrees of freedom operations that are defined as the "roll", "yaw", and "pitch". Normally, the torque that is generated to rotate a rotor includes ripples. The analysis of the torque ripples is important for improving motor performance. In terms of the electric analysis, torque ripple occurs as a result of many factors, including the rotor and stator structures, the distribution of the air-gap flux density, and the waveform of the current in the coils. In particular, the torque ripple is an important factor in the stable operation of the Multi-D.O.F. SPM. Therefore, in this work, the torque ripple was analyzed using various types of magnetization for the permanent magnet. An improved model was proposed for the Multi-D.O.F. SPM based on this analysis.

• Journal of the Korean Society of Food Culture
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• v.20 no.6
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• pp.638-643
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• 2005

As Korea has approached the aging society, older Koreans have become an important force in restaurant sales today. To succeed with this silver market, it is important for restaurant managers to know who they are and what factors influence older Koreans' eating-out decision making process. The purpose of this study was to investigate the effect of the silver consumers' education level on eating-out decision making process. Data were collected from 178 older consumers above 55 years old and analyzed using the descriptive statistic analysis, MANOVA, and one-way ANOVA. The results showed that the elderly consumers' education level significantly influenced the decision making process in determining where to eat out. Significant differences were found in the Problem Recognition Step(Wilks' Lambda=0.817, F=2.991), Information Search Step(Wilks' Lambda=0828, F=2.218), Alternative Evaluation Step II(Wilks' Lambda=0.741, F=3.596), Purchase Decision Step(Wilks' Lambda=0.859, F=2.223), and the Post-Purchase Behavior(Wilks' Lambda=0.885, F=1.780). The higher education level was, the more directly involved in the eating out decision process. The elderly consumers with university education were likely to 'propose to eat out by themselves'(F=9.346), to obtain restaurant information from the 'printed materials'(F=7.452), to go to 'family restaurant'(F=9.057), 'Japanese restaurant'(F=8.7891) and 'fine dining restaurants'(F=3.936), and to directly express their emotion when they had complaints about restaurant service(F=3.206). In conclusion, older Koreans will become more healthy and wealthy which means the dining out activity will be an important part of their life to socialize with people. Therefore, food service operations should consider the elderly consumers' needs and expectation of restaurant services and actively position themselves for this new market segment.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.391-396
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• 2015

Arsenic (As) contamination of agricultural soils resulting from mining activity has caused major concern due to the potential health risk. Therefore the current study was carried out to investigate the relationship between fractionation of As in soil and rice uptake and to provide a basic information for adequate management of As contaminated agricultural soil. Twenty agricultural soils and rice affected by the abandoned mining sites were collected. Soil chemical properties and As concentrations (total and sequential extracted) in soils were determined and As concentrations in polished rice were analyzed. The average concentration of As in non-specifically adsorbed (F1), specifically adsorbed (F2), amorphous hydrous oxides of Fe and Al (F3), crystalline hydrous oxides of Fe and Al (F4) and residual phase (F5) were 0.08, 1.38, 10.34, 3.26 and $10.98mgkg^{-1}$, respectively. Both soil pH and available phosphorus were positively correlated with the concentrations of As in F1 and F2. These results indicate that increasing the soil pH and available phosphorus can significantly increase the easily mobile fractions of As (F1 and F2). The average concentration of As in polished rice was $0.09mgkg^{-1}$. The concentrations of As in F1 and F2 showed a positive correlation with the concentrations of As in polished rice. Therefore soil pH and available phosphorus affect the distribution of As fractionation in soils and thus affect As bioavailability.

• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.308-313
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• 2013

Among 179 specimen diagnosed with ASCUS but did not go through biopsy or other tests, 26 cases (14.52%) showed positivity in HPV Hybrid Capture II Test. There were 25 cases of HPV high risk factor(+), marking 13.96%, and 3 cases of low risk factor(+) at 1.67%. According to cytology manifestation, patients with over LSIL can increase their complete recovery rate with continuous tests, but most patients diagnosed ASCUS do not go through any tests at all. It is considered that in order to prevent and start early treatment on cervical cancer, the HPV Hybrid Capture II Test must be enforced to patients diagnosed with ASCUS. Negative patients should go through routine screening, and positive patients should receive treatment after colposcopy.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1799-1805
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• 2014

In this article, we described about the preparation and electrochemical properties of a flexible energy storage system based on a plastic polyethylene terephthalate (PET) substrate. The PET treated with UV/ozone was fabricated with multilayer films composed of 30 polyaniline (PANi)/graphene oxide (GO) bilayers using layer-by-layer assembly of positively charged PANi and negatively charged GO. The conversion of GO to the reduced graphene oxide (RGO) in the multilayer film was achieved using hydroiodic acid vapor at $100^{\circ}C$, whereby PANi structure remained nearly unchanged except a little reduction of doping state. Cyclic voltammetry and charge/discharge curves of 30 PANi/RGO bilayers on PET substrate (shorten to PANi-$RGO_{30}$/PET) exhibited an excellent volumetric capacitance, good cycling stability, and rapid charge/discharge rates despite no use of any metal current collectors. The specific capacitance from charge/discharge curve of the PANi-$RGO_{30}$/PET electrode was found to be $529F/cm^3$ at a current density of $3A/cm^3$, which is one of the best values yet achieved among carbon-based materials including conducting polymers. Furthermore, the intrinsic electrical resistance of the PANi-$RGO_{30}$/PET electrodes varied within 20% range during 200 bending cycles at a fixed bend radius of 2.2 mm, indicating the increase in their flexibility by a factor of 225 compared with the ITO/PET electrode.

• Carbon letters
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• v.18
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• pp.43-48
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• 2016

Sulphonated polysulphone (SPS) has been synthesized and subsequently applied as binder for graphene oxide (GO)-based electrodes for development of electrochemical supercapacitors. Electrochemical performance of the electrode was investigated using cyclic voltammetry in 1M Na₂SO₄ and 1M KOH solution. The fabricated supercapacitors gave a specific capacitance of 161.6 and 216.8 F/g with 215.4 W/kg and 450 W/kg of power density, in 1M Na₂SO₄ and 1M KOH solutions, respectively. This suggests that KOH is a better electrolyte than Na₂SO₄ for studying the electrochemical behavior of electroactive material, and also suggests SPS is a good binder for fabrication of a GO based electrode.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.489-490
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• 2001

해초가 밀생하기에 알맞은 연안 환경을 지닌 우리나라의 경우, 해초생태계에 관한 연구가 얼마 전까지만 해도 부진하였으나, 최근 들어 제주도와 광양만 잘피밭을 중심으로 활발히 연구가 진행되고 있다. 그 결과 해초의 형태 및 생활사 등에 관한 연구(Kong, 1981, 1982), 해초지 어류 군집에 관한 연구(Huh, 1986; Go and Cho, 1997a; Huh md Kwak, 1997d), 해초지에 서식하는 어류의 먹이습성에 관한 연구(Go et al., 1997b; Huh and Kwak,1997a, b, c,1998a, b, c, d, e, f), 저서생물에 관한 연구(Yun et al., 1997), 새우류에 관한 연구(Huh and An, 1997), 게류에 관한 연구(Huh and An, 1998), 부착해조류에 관한 연구(Huh et al., 1998) 등 다양한 연구 결과가 발표되고 있다. (중략)