• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.28 no.2
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• pp.46-57
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• 2017

Attention-deficit hyperactivity disorder (ADHD) is a common psychiatric disorder that can affect individuals across their lifespan. It is characterized by the core symptoms of inattention, impulsivity and hyperactivity. ADHD develops as a result of the complex interplay between genetic and environmental factors. Children and adults with ADHD usually suffer concomitantly from other psychiatric comorbidities, including both externalizing and internalizing disorders. It is associated with functional impairment and poor long-term outcomes. This review aims to summarize the key findings from recent research into ADHD and its prevalence, core symptoms, cause and comorbidities from childhood to adulthood.

• Journal of Korean Dental Science
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• v.8 no.1
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• pp.28-35
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• 2015

Purpose: To investigate the influence of crown margin design on the stress distribution and to localize critical sites in maxillary canine under functional loading by using three dimensional finite element analysis. Materials and Methods: The bite force of 100 N, 150 N, and 200 N was applied with an angulation of $45^{\circ}$ to the longitudinal axis of tooth. Six models were restored with IPS e.max (Ivoclar Vivadent, Schaan, Liechtenstein) with a different margin design. With lingual ledge and various thicknesses, three different core ceramics were designed in each model. Result: In the core ceramic, the maximum tensile stresses were found at the labiocervical region. In the veneering ceramic the maximum tensile stresses were found at the area where the force was applied in all models. Conclusion: Shoulder and chamfer margin types are acceptable for all-ceramic rehabilitations. A ledge on the core ceramic at cervical region may affect the strength of all-ceramic crowns.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.3101-3101
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• 2001

Near Infrared spectroscopy (NIR) used on human skin measurement was explored in the past decade. Many publications in different journals and magazines discussed the feasibility of the NIR technique for cosmetic product property studies. Based upon the results of pioneers, we have pursued some work of the NIR instrument coupled with a probe module for skin measurement in vivo and vitro. In part I of this paper, the specific Near Infrared spectroscopy instrument stability, human subject conditions and other parameters, which could affect the measurements reproducibility are discussed. Second derivative NIR spectra and Principle Components Analysis (PCA) are utilised for data interpretation. In part II of this paper, the relationship of human skin moisture and ageing, the gender information and finally, the discovery of penetration depth of NIR incident light on skin are reported. A theoretical penetration depth calculation equation is proposed. In part III, the study results of a couple of commercial skin care products effect will be described. The skin lotions were applied on human skin (in vivo) in order to exam the NIR feasibility to monitor the changes of moisture level. The results are consistently positive. From our primary study, it can conclude that the NIR is potentially a very powerful instrument for skin condition diagnostics, either for cosmetic and/or for medication purposes.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.47-53
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• 2004

Emulsion polymerization ws carried out using Alkyl methacrylate(RMA) like MMA, EMA, BMA and Styrene Monomer(SM) for core-shell latex preparation. It was synthesized at $80^{\circ}C$ in the presence of anionic surfactant SLS(Sodium Lauryl Sulfate). FT-IR and DSC analysis are used to confirm the synthesized core-shell emulsion latexes. Moreover DSC and TGA were used to investigate the thermal characterisitcs of them. The differences of the decomposition rate and the activation energy from TGA and DSC analysis are not so big. It considers that the pendent group is not affect of the thermal characteristics and stability on core-shell latexes, which is synthesized with RMA and Styrene. For investigating combustion products, LC50 values were calculated by FED(Fractional Effective Dose)from the Pyrolyzer-Mass sepctrometer.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2601-2610
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• 1993

A numerical study on the melting process inside an isothermal spherical capsule is made. It is assumed that the phase change medium of its solid phase is heavier than the liquid phase and therefore the unmelted solid core is continuously moving downward on account of gravity forces. Such a gravity-assisted melting is commonly characterized by the existence of a thin liquid film below the solid core. The present study is motivated to present a full-equation-based analysis of the influences of the initial subcooling and the natural convection on the fluid flow and heat transfer characteristics associated with the gravity-assisted melting. In the light of the solution strategy, the present study is substantially distinguished from the existing works in that the complete set of governing equations in both the melted and unmelted regions are resolved without subdivision of the solution domains. For example, the liquid film region and the upper melted region are treated here as one domain and thus obviating laborious efforts to couple them. Numerical results are obtained by varying the Rayleigh numbers and the degree of subcooling. For the range of parameters examined, the presence of subcooling was found to impede the melting rate. The dropping velocity of the unmelted solid core was observed to affect the natural convection in the liquid significantly. When compared with the available experimental data, much improved prediction was achieved.

• Progress in Superconductivity and Cryogenics
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• v.17 no.2
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• pp.31-35
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• 2015

Mapping is a useful tool in the magnetic field analysis and design. In some specific research area, such as the nuclear magnetic resonance (NMR) or the magnetic resonance imaging (MRI), it is important to map the magnetic field in the interesting space with high accuracy. In this paper, an indirect mapping method in the center volume of an air-core solenoid is presented, based on the solution of the Laplace's equation for the field. Through the mathematical analysis on the mapping calculation, we know that the condition number of the matrix, generated by the measurement points, can greatly affect the error of mapping result. Two different arrangement methods of the measurement points in field mapping are described in this paper: helical cylindrical line (HCL) method and parallel cylindrical line (PCL) method. According to the condition number, the HCL method is recommended to measure the field components using one probe. As a simple example, we mapped the magnetic fields in a MRI main magnet system. Comparing the results in the different methods, it is feasible and convenient to apply the condition number to reduce the error in the field mapping calculation. Finally, some guidelines were presented for the magnetic field mapping in the center volume of the air-core solenoid.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.3
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• pp.224-229
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• 2012

The importance of ventilation system is being emphasized by interest of indoor air quality. Especially, heat recovery ventilation system has attracted attention as most effective ventilation plan. Because it can reduce hazardous construction materials, indoor air pollutions, and also can reduce air conditioning energy cost. In heat recovery ventilator, the element core is the most important part. The element core is composed of liner and spacer. And liner and spacer are stacked alternately. On the Liner, heat and humidity transfer are made between supply and exhaust air. And spacer plays a role as a tunnel of exhaust and supply. In this study, we investigated and analyzed the efficiency of a heat recovery ventilator, when the spacer's properties are changed. As a result, difference spacer's properties affect an efficiency of heat recovery ventilator.

• Journal of Digital Convergence
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• v.7 no.3
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• pp.35-47
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• 2009

The IS project is getting more and more complicated and large-scaled. Many researchers and practitioners are interested in the IS development methodologies, automated tools and techniques, TQM to decrease project failure, and to increase IS performance. But, in spite of such various efforts, the latest Standish Group's research indicates that the project scale is bulkier than $1{\sim}2$ year ago and IS development project's batting average falls from 34% to 28% at the same time, proceeded project is increased, and project discharged arrives to $15%{\sim}18%$. According to a research, success possibility increased by 37% after a year of PMO introduction, and increased sharply by 62% after 2 years and by 65% after S years. This research has a goal to survey how the PMO function and operation type affect the IS project performance in the financial industry. I determine nine independent variables and three dependent variables from previous researches. The results of this study are that the four core functions of PMO have relationship with project performance. But, technical support function does not relate with organization performance. Among the four core PMO operation types, three types have an effect on the IS project performance except the perfectionist type.

• 전자공학회논문지 IE
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• v.46 no.2
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• pp.1-6
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• 2009

The inductor needs to have the desire of super miniaturization, substance of high density and no electronic obstacle. In this study, it analyzes electromagnetic field properties of the core due to inserted high current to develop union type inductor. As the results, it appears high electromagnetic field in inductor insides, but magnetic is very small in inductor surfaces. Also, magnetic distribution are almost 0[T] in circumferences get out of the inductor surfaces. It is an evidence that magnetic distribution as the electronic magnetic obstacle does not appear at other electronic parts. These above results affect to develop the union type inductor, especially it can be expect to help analysis of electromagnetic field properties of inductor core and reliability improvement.

• The Journal of Korean Academic Society of Nursing Education
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• v.20 no.4
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• pp.548-557
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• 2014

Purpose: This study investigates the level of nursing professionalism and factors that affect nurse perceptions. Method: This study is a descriptive study involving 443 nursing students from two universities. Data were collected in September 2012 via a structured self-report questionnaire and subsequently analyzed using descriptive statistics, t-tests, one-way ANOVA, Pearson correlation coefficients, and multiple regression. Results: The mean scores for nurse image, core elements of nursing professionalism and nursing professionalism were $3.65{\pm}.46$, $4.17{\pm}.39$ and $3.59{\pm}.45$, respectively. Nursing Professionalism had a significant positive correlation with nurse image (r=.749, p<.001) and core elements of nursing professionalism (r=.365, p<.001). In multiple linear regression, factors that influenced nursing professionalism were: temperament as nurses, professionalism, vision of career, role performance of nurses' image, and fundamental nursing practical experience. These variables explained about 58.8% of the total variance in nursing professionalism. Conclusion: For more positive nursing professionalism among students, more attention should be paid to enhancing the positive image of nurses. Doing so can serve as a fundamental resource for the development of appropriate strategies for nursing professionalism.