• Korean journal of food and cookery science
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• v.24 no.3
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• pp.325-332
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• 2008

The purpose of this study was to analyze the gap in perceived sanitaion management importance-performance for school foodservice facilities and utilities. Questionnaires were delivered to 200 dietitians who are employed in school foodservice. A total of 108 were usable, resulting in an 54.0% response rate. Statistical analyses were performed using the SAS package program(version 8.2 for Windows) for descriptive analysis, t-tests, and importance-performance analysis (IPA). Among the respondents, 58.3% of the dietitians had more than 10 years of work experience, 81.5% were university graduates, and 64.8% worked in elementary schools. Also, 89.8% of the school foodservices provided meals once a day. According to the importance and performance analysis for 25 items, significant differences were found between importance and performance and the importance score was significantly higher than the performance score for all of the items. The results of IPA showed the following areas as improvement priorities: physical separation between the clean areas and the unclean areas to prevent cross-contamination, and proper management of the temperature and humidity within kitchens and food storage facilities. Overall, the IPA results indicated that the items in need of urgent need of improvement will require political support, and above all, continued research. Finally, better models of foodservice facilities and utilities are needed to improve and modernize the operating conditions of these various foodservice establishments.

• Polymer(Korea)
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• v.30 no.5
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• pp.380-384
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• 2006

Polyhedral oligomeric silsesquioxanes (POSS) were used as starting materials for the preparation of hybrid materials with polystyrene (PS). Optically transparent hybrids were obtained in a wide range of weight ratios when phenyl groups were introduced to each corner of the silsesquioxane. In contrast, as cyclohexyl groups were introduced, the obtained hybrid materials with PS resulted in turbid films. The aromatic (${\pi}-{\pi}$) interaction was confirmed to be a quite effective tool for the synthesis of organic-Inorganic polymer hybrids with POSS. The obtained homogeneous and transparent hybrid films could be dissolved in solvents and East again without any separation. The homogeneity of polymer hybrids with POSS was supported by the result of scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC), which demonstrated a nanometer-level integration of PS and POSS.

• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.73-78
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• 2013

Hexadecane and exfoliated graphite nanoplate (xGnP)composite was prepared as a shape-stabilized phase change material (SSPCM) in a vacuum to develope thermal energy storage. The Hexadecane as an organic phase change material (PCM) is very stable against phase separation of PCM and has a melting point at $18^{\circ}C$ that is under the thermally comfortable temperature range in buildings. The xGnP is a porous carbon nanotube material with high thermal conductivity. Scanning electron microscope (SEM) and Fourier transformation infrared spectrophotometer (FT-IR)were used to confirm the chemical and physical stability of Hexadecane/xGnP SSPCM. In addition, thermal properties were determined by Deferential scanning calorimeter(DSC) and Thermogravimetric analysis (TGA). The specific heat of Hexadecane/xGnPSSPCM was $10.0J/g{\cdot}K$ at $21.8^{\circ}C$. The melting temperature range of melting and freezing were found to be $16-25^{\circ}C$ and $17-12^{\circ}C$. At this time, the laten heats of melting and freezing were 96.4J/g and 94.8J/g. The Hexadecane was impregnated into xGnP as much about 48.8% of Hexadecane/xGnP SSPCM's mass fraction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.747-749
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• 2017

To protect financial services against danger of financial accidents and customer information leakage caused by malware, injection attack and so on, Financial Services Commission announced "Financial Networks Security Enhancement Comprehensive Plan", which suggests the guideline of protecting customer information and providing secure financial services by separating network topology and then makes the financial company use network partitioning system. In consequence of this policy, financial companies respectively chose between the physical partitioning mechanism or the logical partitioning mechanism according to their IT environment. This paper suggests an efficient infrastructure configuration plan for making the logical network partition, by comparison of a construction of traditional general equipment and an integrated HCI(Hyper Converged Infrastructure) through 'Hyper Converged' which is one of virualization techniques for developing currently, and the case study of the integrated HCI method.

• The Journal of the Petrological Society of Korea
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• v.26 no.4
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• pp.353-360
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• 2017

The preservation treatment for the outer rampart of Namhansanseong fortress is needed due to partial collapse and separation of stone materials. In this study, we investigated the petrological features of the stone materials used for the outer rampart and estimated their provenances through the geologic survey. Through the above study, the suitable replacement stone in the maintenance of outer rampart were suggested. The stone materials of the above outer rampart consist of the banded gneiss, augen gneiss, granitic gneiss and porphyroblastic gneiss. Among these four kinds of rocks, granitic gneiss is quantitatively the most abundant. Petrological comparisons between stone materials and rocks distributed around the fortress, lead to the conclusion that the above materials are likely to have been delivered from around the fortress. Judging from the results of the comparison on frequency of use and strength characteristics among the above rocks, the granitic gneiss is considered to be suitable for restoration of the outer rampart of the fortress.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.27 no.1
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• pp.72-81
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• 2016

Objectives: The purpose of this study was to evaluate anti-depressive effects of exercise on child and adolescent and its association with brain derived neurotrophic factor (BDNF). Methods: Twenty nine middle school boys (age $13.3{\pm}0.7$) were divided into two groups, 15 boys for control group and 14 in the experimental group. The control group participated in a regular exercise program, 3 times a week for 15 weeks. During the same period, the experimental group participated in an aerobic exercise program specifically designed to enhance anti-depressive effect of exercise. Serum BDNF level and its performance of each group on the Beck Depression Index (BDI), Children's Depression Inventory (CDI), Screen for Child Anxiety Related Emotional Disorders (SCARED), Aggression Questionnaire (AK-Q), and Stroop task were compared before and after the exercise program. Results: Scores of BDI, CDI, SCARED, and AK-Q were significantly lower in both groups after the exercise programs compared to those before the programs. The Stroop task performances were significantly improved after the programs. However, there were no significant differences between two exercise programs, except SCARED separation anxiety, AK-Q physical, and verbal aggression scores. Also, no association was found between serum BDNF level and anti-depressive effects of exercise. Conclusion: Our preliminary results suggest a possible effect of exercise on depression, anxiety, aggression, and cognition of child and adolescents.

• Korean Journal of Occupational Health Nursing
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• v.19 no.1
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• pp.28-40
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• 2010

Purpose: The purpose of the study >was to examine the prevalence of work-related musculoskeletal disorders(WMSDs) and to identify the relationship between work-related psychosocial and acculturative factors and WMSDs among Korean-Chinese workers living in Korea. Methods: A cross-sectional survey was conducted with 195 Korean-Chinese workers who have worked full-time for the past 6 months. A structured questionnaire, including measures for musculoskeletal symptoms, physical demand, work-related psychosocial(job demand, job control, interpersonal conflict), acculturative (acculturation strategy and acculturative stress), and personal factors, was used. Descriptive statistics and logistic regression analysis were conducted using the SPSS WIN 17.0. Results: The prevalence of WMSDs was 64.1%. In comparison to Korean workers, job demand of this group was lower while both interpersonal conflict and lack of job control were higher among them. Integration was the most commonly used acculturation strategy and mean scores of acculturative stress were below the median. Acculturative stress was positively correlated with integration and assimilation while negatively correlated with separation and marginalization. Interpersonal conflict and integration appeared to be related to WMSDs among male and female Korean-Chinese workers, respectively. Conclusion: The WMSD interventions need to be planned in consideration of different influences of work-related psychosocial and acculturative factors on WMSDs by gender.

• Korean Journal of Materials Research
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• v.21 no.6
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• pp.327-333
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• 2011

Nanostructured cobalt materials have recently attracted considerable attention due to their potential applications in high-density data storage, magnetic separation and heterogeneous catalysts. The size as well as the morphology at the nano scale strongly influences the physical and chemical properties of cobalt nano materials. In this study, cobalt nano particles synthesized by a a polyol process, which is a liquid-phase reduction method, were investigated. Cobalt hydroxide ($Co(OH)_2$), as an intermediate reaction product, was synthesized by the reaction between cobalt sulphate heptahydrate ($CoSO_4{\cdot}7H_2O$) used as a precursor and sodium hydroxide (NaOH) dissolved in DI water. As-synthesized $Co(OH)_2$ was washed and filtered several times with DI water, because intermediate reaction products had not only $Co(OH)_2$ but also sodium sulphate ($Na_2SO_4$), as an impurity. Then the cobalt powder was synthesized by diethylene glycol (DEG), as a reduction agent, with various temperatures and times. Polyvinylpyrrolidone (PVP), as a capping agent, was also added to control agglomeration and dispersion of the cobalt nano particles. The optimized synthesis condition was achieved at $220^{\circ}C$ for 4 hours with 0.6 of the PVP/$Co(OH)_2$ molar ratio. Consequently, it was confirmed that the synthesized nano sized cobalt particles had a face centered cubic (fcc) structure and with a size range of 100-200 nm.

• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.387-392
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• 2005

Recently, dimethyl carbonate (DMC) is considered as an alternative of MTBE (methyl tert-butyl ether), additive for non-leaded gasoline with their fast biodegradation rate and low toxicity. DMC is usually synthesized so far by oxidative carbonylation of methanol, and recently developed synthetic process is also started with methanol. Since the phase equilibria of the system, consisted of DMC and methanol or other reaction products on different temperature and pressure is necessary for the optimum separation process design and operation. However the reported phase equilibria and physical properties for DMC mixtures in the Dortmund Data Bank (DDB; thermodynamic property data bank) are quite rare. Besides, infinitely dilute properties are not found. In this work, isothermal vapor-liquid equilibria at 333.15 K for methanol+DMC binary system and mixing properties, excess molar volume and viscosity deviation at 298.15 K are directly measured and correlated. Additionally, infinitely dilute activity coefficient of methanol in the DMC solvent at three different temperatures are measured and compared with predicted values using modified UNIFAC (Dortmund).

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.255-261
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• 2016

Adsorption experiments of Acid Yellow 14 dye using activated carbon were carried out as function of adsorbent dose, pH, initial concentration, contact time and temperature. The equilibrium adsorption data were analyzed by Langmuir, Freundlich and Temkin isotherm model. The experimental data were best represented by Freundlich isotherm model. Base on the estimated Freundlich constant (1/n=0.129~0.212) and Langmuir separation factor ($R_L=0.202{\sim}0.243$), this process could be employed as effective treatment method. The heat of adsorption of Temkin isotherm model was 5.101~9.164 J/mol indicated that the adsorption process followed a physical adsorption. Adsorption kinetics experimental data were modeled using the pseudo-first-order and pseudo-second-order kinetic equation. It was shown that pseudo-second-order kinetic equation could best describe the adsorption kinetics. Base on the negative Gibbs free energy (-4.81~-10.33 kJ/mol) and positive enthalpy (+78.59 kJ/mol) indicate that the adsorption is spontaneous and endothermic process.