• Journal of Korean Society for Atmospheric Environment
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• v.30 no.6
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• pp.519-530
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• 2014

Twenty four individual polycyclic aromatic hydrocarbon (PAH) compounds both in gas- and particle-phase were quantified in three tunnels (Namsan Tunnel 3, Jeongneung Tunnel, Bukak Tunnel) to characterize vehiculate emission of PAHs. Gas phase PAHs were dominant in tunnels which consisted of 85% of total PAHs concentrations. Naphthalene and 2-methyl naphthalene were the most abundant gas phase PAH compounds, while the concentrations of fluoranthene and pyrene were highest in the particle phase. Most (96%) of the gas phase PAH compounds consisted of two- and three-aromatic rings whereas most of the particle phase PAHs were in four and five-rings (67%) in tunnels. Average BaP-eq concentrations of PAHs in the particle phase ($20.8{\pm}11.6ngm^{-3}$) was about twenty fold higher than that in the gas phase ($1.6{\pm}0.6ngm^{-3}$). It means that the particle phase PAHs has more adverse health effect than the gas phase PAHs even though the concentrations of the particle phase PAHs were lower than those of the gas phase PAHs. Compared to previous studies reporting diagnostic ratios for specific PAH compounds, the profile of individual PAH compounds measured in this study reflected well for the vehiculate emissions. We reported, for the first time, on the results of the profile of individual PAH compounds measured in tunnels for both gas and particle phases.

• Journal of Korean Academy of Nursing
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• v.17 no.1
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• pp.24-32
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• 1987

This study was designed to investigate the changes of nurses' role model, perceptions toward occupation, and self actualization value in terms of the phases of socialization process. Two hundred and sixty nine nurses working in clinical settings were randomly selected from 15 general hospitals despersed over Seoul and Kyungki province. Data were gathered by the standardized Perceptual Orientation Test, the Self-actualization Test, and Questionnaires on role models and phases of socialization process developed by the investigators from October 1985 to March 1986. The data were analysed by ANOVA and Pearson's Correlation Coefficient. The results were as follows: 1. The average time period required for the shift of phases of socialization process were; phase Ⅰ, role adjustment, took average 10 months of employment: Phase Ⅱ, interpersonal adjustment, 12 months: and Phase Ⅲ, role conflict, 15 months respectively. Conflict resolution, phase Ⅳ, began to take place 18 months of employment; and shifted to phase V, internalization and self-actualization at 25 months of employment. 2. Throughout 5 consecutive phase, the number of immediate superior nurse model was dominantly the highest among the role models. The number of head nurse role model increased at phase Ⅱ, phase Ⅲ, and phase Ⅳ. Respondents with school model in phase I tended to transfer to work model at phase Ⅱ. 3. The perceptions toward occupation were not significantly influenced by the Phases of socialization process. 4. The score of self-actualization value was not significantly influenced by the phases of socialization process. 5. In regard to perceptions toward occupation, nursing director model group showed significantly lower score in phase I (p<.01). 6. The comparison of self-actualization value between the 5 phases revealed significant difference in phase I: in particular among respondents with school model at p<.05. To conclude: 1. The phase Ⅲ of socialization process is the period of role conflict which occur at 15 months of employment, an6 conflict resolution, phase Ⅳ, begins at 18 months of employment on the average in clinical settings. 2. The immediate superior nurse and the head nurse are important role models for nurses all through their socialization process.

• Journal of the Korean Society for information Management
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• v.4 no.2
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• pp.47-61
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• 1987

Main advantages of an analytico-synthetic scheme are its flexibility and its ability to cope with new subjects as they arise. Accordingly the synthetic scheme can keep pace with changes in knowledge more easily than an enumerative scheme because new subjects often merely involve fresh combinations of basic unit parts already listed. The findings of the study are as follows: 1. Each part of the components of a complex subject is called phase in CC and we are able to obtain three levels of phase relations such as intra-facet phase relation, intra-array - phase relation and inter-subject phase relation. 2. Different digits are used in CC to represent different varieties of phase relation in each levels. 3. The mode of phase relation may be taken to indicate the strength of bond between the phase and may form a new main subject. 4. In the rules and grammar of the phase relation the extension of two-phase subject is possible up to any extent theoritically. 5. Phase relation in DDC was introduced in the 18th edition, but there was no provision for the kind and the level of phase relation. 6. Colon(:) of the UDC is used to represent phase relation but there was also no provision for the kind and the level of phase relation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.576-585
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• 2016

The current control methods of Y-connected 7 Phase BLDC motor are sine wave current control and square wave control. The sine wave current control method needs dq axis transformation of $7{\times}7$ matrix for current control and very complex. Also this method is not suitable for multi Phase BLDC motor of trapezoidal back emf wave. Therefore, in Y connected multi phase BLDC motor, the square wave current control methods are required. Generally, in the 3Phase BLDC system, Average current control method is used for current control. The average current is obtained that the summation of absolute value of each phase current magnitude is divided by the number of conduction phase. However, if average current control method is applied to multi-phase system, there is a problem that each phase currents are different. This problem affects unbalance of each phase torque and fluctuation of total torque. This paper proposed each phase current control method of Y connected 7Phase BLDC system. Proposed method is used for PI controller of each phase for each phase current control. This method can perfect square wave current control. Also, configuration of the method is easier than DQ axis transformation. Proposed method is verified through simulation and experiments.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.10
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• pp.1419-1424
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• 2001

Previous research in our laboratory has demonstrated the importance of lactose in phase I and II pig starter diets. Two experiments were conducted to evaluate the use of a carbohydrate by-product (food by-products) as a replacement for lactose. In Exp. I, 120 weaned pigs ($14{\pm}2d$ and 5.65kg) were allotted in a randomized complete block design (RCBD) to 10 replications with four pigs per pen. This experiment evaluated three carbohydrate sources (lactose, carbohydrate by-product, and 50-50 blend of the carbohydrate by-product and lactose). The carbohydrate sources were added at 26% in the phase I diets and 15% in the phase II diets. Phase I diets contained 7.5% spray dried plasma protein (SDP). The phase I diets were fed from d 0 to 14 and the phase II diets from d 15 to 28. There were no significant differences between carbohydrate sources on pig performance in phase I. However, during phase II pigs fed the diet with lactose had an improved gain/feed ratio (G/F) (p=0.06) compared to pigs fed the carbohydrate by-product. For the entire 28 d trial ADG, ADFI and G/F were similar for the 50-50 blend and those fed lactose. Total replacement of lactose with the carbohydrate byproduct resulted in a reduced G/F (p=0.09). Exp. 2 used 100 weaned pigs ($17{\pm}2d$ and 4.75kg) with five replications with five pigs per pen. This experiment evaluated four carbohydrate treatments (lactose, carbohydrate by-products, 50-50 blend, and corn). All phase I diets contained 3.5% SDP with the carbohydrate sources included at 15%, and were fed d 0 to 14. The phase II diets contained 7.5% of the carbohydrate sources and were fed d 15 to 27. A common phase III diet was fed d 28 to 42. During all phases pigs fed com tended to have a lower ADG than pigs fed the other carbohydrate sources with the 50-50 blend resulting in the highest ADG. The results of both experiments suggest that this carbohydrate by-product can replace at least 50% of the lactose in phase I and phase II pig starter diets.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.274-284
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• 1994

Phase Inversion Temperature (PIT) measurements showed that the addition of polar components such as oleyl alcohol and oleic acid to the system comprising n-dodecylpentaoxyethylene monoether ($C_{12}E_5$), nonpolar oil (n-hexadecane) and water produced large reductions in the PIT. The PIT was lowered as the additive-to-surfactant ratio in the surfactant films in the microemulsion phase was increased. Another dramatic effect of additive was the manner in which it affects the volume of the microemulsion phase at the PIT of the oil and water solubilization characteristics. Microemulsion phase volume was increased rapidly with decreasing PIT, i.e., with increasing amounts of additive in the system. Also with a decrease in PIT, the solubilization parameters of both oil and water in the microemulsion phase were strikingly increased. Even though soil removal data were not available for the conditions where our results obtained, PIT measurement seems a useful starting point for estimating conditions when middle-phase microemulsion formation and its associated high solubilization of oil can be expected.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.777-786
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• 2003

The phase noise characteristics of the phase-locked loop frequency synthesizer were predicted based on the analysis for phase noise contribution of noise sources. The proposed phase noise model in this paper more accurately predicts the phase noise spectrum of frequency synthesizer. To accurately model the phase noise contribution of noise sources in frequency synthesizer, the phase noise sources were analyzed via modeling of the frequency divider and phase noise components using Leeson model for reference signal source and VCO. The phase noise transfer functions to VCO from noise sources were analyzed by superposition theory and linear operation of phase-locked loop. To evaluate the phase noise prediction model, the frequency synthesizers were fabricated and were evaluated by measured data and prediction data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5A
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• pp.290-297
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• 2012

In this paper, we proposed new modulation schemes, Offset Phase Rotation Shift Keying (OPRSK) and Phase Shift Rotation Shift Keying (PSRSK), for medical in-body wireless body area network (WBAN) systems. In IEEE, the WBAN system is assigned as 802.15. Task Group (TG) 6, and the related standardization is being progressed. Recently, in this Group, Phase Silence Shift Keying (PSSK), Phase Silence Position Keying (PSPK) and Phase Rotation Shift Keying (PRSK), which can obtain higher power efficiency, are proposed as new modulation schemes for low-power operation of WBAN system. However, they have a disadvantage for non-linear amplifier distortion. Therefore, in this paper, we proposed OPRSK and PSRSK, which are robust to non-linear amplification, by employing a phase offset in constellation and a power distribution in symbol duration, and verified that the proposed methods have good perfomance and stable operation through performance evaluation.

• Journal of the Korean Society for Heat Treatment
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• v.25 no.2
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• pp.74-79
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• 2012

This study has been carried out to investigate the precipitation behavior of ${\chi}$ phase and effect of ${\chi}$ phase precipitation on the impact toughness of 25%Cr-7%Ni-4%Mo super duplex stainless steel. It was proved that the ${\chi}$ phase was a intermetallic compound, which represented the higher chromium and molybdenum concentration than the matrix phases, and also showed the higher molybdenum concentration than the ${\sigma}$ phase. The ${\chi}$ phase was precipitated at the interface between ferrite and austenite or inside the ferrite matrix in the early stage of aging. The number of ${\chi}$ phase precipitates increased with increasing aging time, however, after showing the maximum value, the number was decreased due to the gradual transformation of ${\chi}$ phase into ${\sigma}$-phase. Aging ferrite phase was decomposed by the $r^2$ phase and ${\sigma}$-phase. Impact toughness rapidly decreased with time in the initial stage of aging at ${\chi}$ phase start to precipitate. Thus, the impact toughness was greatly influence for the precipitation of ${\chi}$ phase.

• 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.