• Progress in Superconductivity and Cryogenics
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• v.10 no.3
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• pp.36-42
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• 2008

The superconducting motor shows several advantages such as smaller size and higher efficiency against conventional motor especially utilized in ship propulsion application. However, this size reduction merit appears in large capacity more than several MW. We are going to develop a 5MW class synchronous motor with rotating High-Temperature Superconducting (HTS) coil. that is aimed to be utilized for ship propulsion so it has very low-speed, The ship propulsion motor must generate very high electromagnetic torque instead of low-speed. Therefore. the rotor (field) coils need very large magnetic flux that results in large amount of expensive HTS conductor for the field coil. In this paper a 5MW HTS motor for ship propulsion is considered to be designed with construction cost reduced via HTS field coil cost reduction because HTS conductor cost is critical factor in the construction cost of HTS motor. In order to reduce the HTS conductor amount. iron-cored rotor types are considered. so several cases with iron-core are compared one another and with an air-core case.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2748-2755
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• 2024

This paper presents two new methods for variance reduction for shielding calculation in Monte Carlo radiation transport. One method is CADIS-NEE, which combines Consistent Adjoint Driven Importance Sampling (CADIS) and next-event estimator (NEE) methods to increase the calculation efficiency of tallies at points. The other is CADIS-deterministic transport (DXTRAN), which combines CADIS and DXTRAN to obtain higher performance than using CADIS and DXTRAN separately. The combination processes are derived and implemented in the hybrid Monte-Carlo-Deterministic particle-transport code NECP-MCX. Various problems are tested to demonstrate the effectiveness of the two methods. According to the results, the two combination methods have higher efficiency than using CADIS, NEE or DXTRAN separately. In a long-distance photon-transport problem, CADIS-NEE converges faster than NEE and the figure of merit (FOM) of CADIS-NEE is 75.6 times of NEE. In a labyrinthine problem, CADIS-DXTRAN's FOM surpasses that of DXTRAN and CADIS by a factor of 45.3 and 17.7, respectively. Therefore, it is advisable to employ these two novel methods selectively in appropriate scenarios to reduce variance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.231-237
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• 2016

This paper presents a multiband low phase noise CMOS VCO with wide frequency tunability using switched bondwire inductor bank. The combination of bondwire inductor and CMOS switch transistor enhances frequency tunability and improves phase noise characteristics. The proposed multiband VCO operates from 2.3GHz to 6.3GHz with phase noise of -136dBc/Hz and -122dBc/Hz at 1 MHz offset frequency, respectively. Switched bondwire inductor bank shows high quality factor(Q) at each frequency band, which allows better tradeoff between phase noise and power consumption. The proposed VCO is designed in TSMC 0.18um CMOS process and consumes 7.2 mW power resulting in figure of merit(FOM) of -189.3dBc/Hz at 1 MHz offset from 6GHz carrier frequency.

• Journal of Korean Physical Therapy Science
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• v.3 no.3
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• pp.93-104
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• 1996

The purpose of this study is improvement of clinical practice education through examination of satisfaction on clinical practice of physical therapy students and grasping the factor have on effect on satisfaction of clinical practice. The students of the survey were 328 junior college students and 41 University students selected from 8 junior college and 2 University by questionnaire from Oct. 6 to Oct. 26, 1993. The collected data was analyzed by ANOVA, T-test, Multiple range test (Tukey, LSD, Duncan), principal factor analysis according to purpose of study. The results were as follows : The degree of satisfaction according to the item on clinical practice was low as 0.346 of a total 1.0. The degree of satisfaction of instruction(0.40) revealed to be high. Compared with the degree of satisfaction on contents(0.39), practice environment(0.38), satisfaction after practice(0.36), practice hours(0.35), personalrelations(0.33), problem of practice place(0.31), practice evaluation(0.25) revealed to be low. 1. The degree of satisfaction on clinical practice according to education system was lower junior college than University. 2. The degree of satisfaction on clinical practice according to volitional group and another intention group and another intention group was not different. 3. The degree of satisfaction on clinical practice according to the order of merit was not difference A group, B group, C group, but it of D group was low. 4. The degree of satisfaction on clinical practice according to the time of practise, the group that clinical enforce during a session was higher than the group that it enforce during vacation. 5. The degree of satisfaction on clinical practice according to clinical practice place was high in University hospital and general hospital, but was low in hospital and clinic. 6. The degree of satisfaction on clinical practice according to existence or non-existence of a hospital in affiliation was higher existence a hospital in affiliation group than non-existencea hospital in affiliation group. 7. The degree of satisfaction on clinical practice according to satisfaction of major was high in group of high satisfaction major.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.6
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• pp.465-471
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• 2007

The system efficiency of the proposed Buck-Boost AC-DC converter is increased by soft switching method. The converter includes to merit of power factor correction (PFC) from sinusoidal control of input current. The switching behavior of control switches operates with soft switching by partial resonance, and then the proposed converter has high system efficiency with decrement of switching power loss. The input current waveform in proposed converter is got to be a sinusoidal form of discontinuous quasi-pulse row in proportion to magnitude of AC input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity. The output voltage of the converter is regulated by PWM control technique. The discontinuous mode action of current flowing into inductor makes to simplify control method and control components. The proposed PFC Buck-Boost converter is analyzed to compare with the conventional PFC Buck-Boost converter. Some computer simulative results and experimental results confirm to the validity of the analytical results.

• The Korean Journal of Food And Nutrition
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• v.30 no.1
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• pp.129-138
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• 2017

The purpose of this study was to evaluate the satisfaction with school meal service and the food preference in elementary school students who are in their growth period. A total of 484 students (242 boys) participated and completed a questionnaire survey. The results indicated that the merit of school meals was the highest in 'balanced diet'. 'Food hygiene' and 'delicious food' were the most important factors in school meals. Most of the students wanted 'balance between eastern and western foods' and 'new dishes' for the menu of school meals. For the distribution of meals, 'various kinds of side dishes' and 'warmth of dishes' were mainly required. The main problems of the current environment of school meals were 'long waiting time' and 'noise of the cafeteria'. In satisfaction with the school meal service, the highest satisfactory factor was 'staffs' cleanliness', following 'arrangement of furniture in cafeteria' and 'nutrition information-providing'; whereas, the lowest factor was 'staffs' kindness'. In the preference of foods, students preferred 'white rice'; whereas they did not like 'bean rice'; and 'fried rice' was preferred. In side dishes with meat and fish, most of the meats including 'Tangsuyuk' and 'Bulgogi' were preferred. For fish, 'fried hairtail' was preferred; whereas, 'fried Spanish mackerel' was not. In case of kimchi, 'Chinese cabbage kimchi' and 'cubed radish kimchi' were especially preferred. Considering these results, intensive improvement is required to increase school meal satisfaction by understanding the students' needs. An effort to allow the students' preferences to be reflected in the menu is also needed.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.2
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• pp.137-141
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• 2011

Sunscreen is divided into the organic agent of UV absorption and inorganic agent of reflection. These are evaluated by sun protection factor (SPF) in-vivo test requiring high cost and time, while in-vitro tests are adopted commonly because of short test time, easy result collection. Generally, test method of SPF use SPF 290a by UV-vis spectrometer. The evaluate by SPF 290 has low reproducibility. Although analysis using UV-vis spectrometer has high reproducibility, it is hard to separated results of transmission, adsorption, and reflection. In this study, suggested method of elipsometer has some merit such as high reproducibility, easy separation of transmission/adsorption/re- flection, analysis using various incident angle. We tested the validity of elipsometer for SPF measurement, using commercially available sun-block (SPF 50).

• Journal of the Korean institute of surface engineering
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• v.49 no.1
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• pp.40-45
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• 2016

Recently, $Bi_2Te_3$-based alloys are the best thermoelectric materials near to room temperature, so it has been researched to achieve increased figure of merit(ZT). Ternary compounds such as Bi-Te-Se and Bi-Sb-Te have higher thermoelectric property than binary compound Bi-Te and Sb-Te, respectively. Compared to DC plating method, pulsed electrodeposition is able to control parameters including average current density, and on/off pulse time etc. Thereby the morphology and properties of the films can be improved. In this study, we electrodeposited n-type ternary Cu-doped $Bi_2(Te-Se)_3$ thin film by modified pulse technique at room temperature. To further enhance thermoelectric properties of $Bi_2(Te-Se)_3$ thin film, we optimized Cu doping concentration in $Bi_2(Te-Se)_3$ thin film and correlated it to electrical and thermoelectric properties. Thus, the crystal, electrical, and thermoelectric properties of electrodeposited $Bi_2(Te-Se)_3$ thin film were characterized the XRD, SEM, EDS, Seebeck measurement, and Hall effect measurement, respectively. As a result, the thermoelectric properties of Cu-doped $Bi_2(Te-Se)_3$ thin films were observed that the Seebeck coefficient is $-101.2{\mu}V/K$ and the power factor is $1412.6{\mu}W/mK^2$ at 10 mg of Cu weight. The power factor of Cu-doped $Bi_2(Te-Se)_3$ thin film is 1.4 times higher than undoped $Bi_2(Te-Se)_3$ thin film.

• Structural Engineering and Mechanics
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• v.71 no.4
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• pp.391-405
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• 2019

Compared to the ambient vibration test mainly identifying the structural modal parameters, such as frequency, damping and mode shapes, the impact testing, which benefits from measuring both impacting forces and structural responses, has the merit to identify not only the structural modal parameters but also more detailed structural parameters, in particular flexibility. However, in traditional impact tests, an impacting hammer or artificial excitation device is employed, which restricts the efficiency of tests on various bridge structures. To resolve this problem, we propose a new method whereby a moving vehicle is taken as a continuous exciter and develop a corresponding flexibility identification theory, in which the continuous wheel forces induced by the moving vehicle is considered as structural input and the acceleration response of the bridge as the output, thus a structural flexibility matrix can be identified and then structural deflections of the bridge under arbitrary static loads can be predicted. The proposed method is more convenient, time-saving and cost-effective compared with traditional impact tests. However, because the proposed test produces a spatially continuous force while classical impact forces are spatially discrete, a new flexibility identification theory is required, and a novel structural identification method involving with equivalent load distribution, the enhanced Frequency Response Function (eFRFs) construction and modal scaling factor identification is proposed to make use of the continuous excitation force to identify the basic modal parameters as well as the structural flexibility. Laboratory and numerical examples are given, which validate the effectiveness of the proposed method. Furthermore, parametric analysis including road roughness, vehicle speed, vehicle weight, vehicle's stiffness and damping are conducted and the results obtained demonstrate that the developed method has strong robustness except that the relative error increases with the increase of measurement noise.

• The Korean Journal of Elementary Counseling
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• v.10 no.2
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• pp.185-201
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• 2011

The purpose of this study is to reveal and confirm the factor structure inherent in the Korean inventory of peer relationships(KIPR; Sang-Hwang Hong, et al., 2009) in order to strengthen the interpretive usefulness of the test. For this purpose, the inventory was administered to the total of 616 children in the fourth through sixth grades in three elementary schools located in Gyungnam area, and the data from 578 of them were analyzed. The results of the study can be summarized as follows. First, as a result of the exploratory factor analysis of 3-factor and 4-factor models, the 3-factor model was found to be more appropriate. In the 3-factor model, the factor 1 is named "Lack of Self-Confidence and Social Withdrawal" as it consists of such circumplex scale items as Non-Assertiveness (C5), Social Avoidance (C4), the Cold (C3), and Too Submissive (C6). The factor 2 is named "Too Aggressive and Controlling" and consists of items Too Controlling (C1) and Hard to be Supportive (C2). The factor 3 is named "Too Caring" and consists of items Too Responsible (C7), Over Involvement (C8), and Too Submissive (C6). Second, as a result of the confirmatory factor analysis, the 3-factor model, in comparison to the 4-factor model, was found to better reflect the collected data(RMSEA=.054), its goodness of fit was not satisfactory but within the acceptable range(CFI=.786), and its power of simplicity and clarity was also adequate(PCFI=.733). In the current study, through the exploratory and confirmatory factor analyses of scores from the Korean inventory of peer relationships circumplex scales, scales within the peer relationship circumplex model that are near each other and are highly correlated were confirmed to be grouped together as same factors. I believe the main merit of the study lies in the above result having provided the necessary foundation for forming the superordinate and representative scale that encompasses the eight circumplex scales, which enhances the test's interpretive usefulness.