• Korean Journal of Occupational Health Nursing
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• v.19 no.2
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• pp.190-204
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• 2010

Purpose: This study was conducted to obtain the fundamental data on prevention and management of musculoskeletal symptoms, and to assess the prevalence, risk factors and job characteristics of musculoskeletal symptoms in hotel employees. Methods: The work sampling analysis was carried out by OWAS, and the prevalence was surveyed in term of NIOSH diagnostic criteria and work related risk factors on 263 hotel employees in Busan, Korea, using structured self-administered questionnaire from Jan. 20 to Feb. 26, 2010. The collected data were analysed by the SPSS 18.0. Results: 1) The prevailing rate of musculoskeletal symptoms by NIOSH diagnostic criteria was 43.80% for total subjects and 27.91% for shoulders, 12.79% for neck, and 11.24% for back/waist, respectively. 2) Factors affecting the prevalence of musculoskeletal symptoms were examined and multivariate logistic regression analysis was performed. As a result, women, having a burden of musculoskeletal work, increased work time in case of a higher risk of the prevalence of musculoskeletal symptoms (P<0.1). 3) The body parts and the department with the prevalence of musculoskeletal symptoms showed a significant difference (P<0.05) compared with symptoms on shoulders, arms/elbows, and ankles/feet. Conclusion: The prevalence of musculoskeletal symptoms by NIOSH diagnostic criteria in hotel employees was relatively high showing 43.80% for total subjects and higher in departments of laundry, reservations, cooking, food&beverage, dishwashing, and room cleaning than others.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.3
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• pp.205-209
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• 2017

Unlike spherical drop impact, ellipsoidal drop impact can control the bouncing height on a heated surface by significantly altering impact behavior. To scrutinize the effect of the aspect ratio (AR) of the drop on the bounce suppression, in this study, non-axisymmetric spreading behaviors are observed from two side views and characterized based on the spreading width of the drop for horizontal principal axes. In addition, the maximum spreading width is investigated for various ARs. The results show that as the AR increases, the maximum spreading width of the minor axis increases, whereas that of the major axis shows no significant variation. In the regime of high AR and high impact velocity, liquid fragmentations by three parts are observed during bouncing. These fragmentations are discussed in this work. The hydrodynamic features of ellipsoidal drop impact will help understand bouncing control on non-wetting surfaces for several applications, such as self-cleaning and spray cooling.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.28-35
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• 2004

$N_2$ has been one of the most useful gases in industrial application, for example, plasma ashing, surface cleaning and decomposition of pollution gases. In order to clarify $N_2$ plasma properties and increase practical applications, many experimental and theoretical investigations have been carried out until now on. In this papa, we examined the characteristics of $N_2$ RF Plasmas using one-dimensional fluid model. $N_2$ plasmas showed a double-layer structure in both sheath regions as the power source voltage becomes higher. Generally, a double-layer structure should be showed in electro-negative plasmas, but not in electro-postive plasmas such as $N_2$ discharge. However, most electrons in $N_2$ plasmas lost their energy by many excitation reactions in the near of both electrodes where electron collisions were actively executed and such continuous reactions during an RF period made this structure strong with increase of the power source voltage. The dependence of $N_2$ plasma properties on pressure was also discussed.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.3
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• pp.182-186
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• 2015

We investigated that effects of annealing ambient on the characteristics of functional nano thin film synthesized on glass substrate. The functional nano thin films were annealed by using rapid thermal annealing (RTA) equipment in vacuum, oxygen and nitrogen ambient, respectively. The hardness of the functional nano thin films were measured by a standard hardness testing method (ASTM D3363) such as a H-9H, F, HB and B-6B pencil (Mitsubishi, Japan). Also, the adhesion of the functional nano thin films were measured by a standard adhesion testing method (ASTM D3359) using scotch tape (3M, Korea). The contact angle of the functional nano thin films was measured by a contact angle analyzer (Phoenix 300 Touch, S.E.O.). The optical property of functional nano thin films was measured via UV-visible spectroscopy (S-3100, Scinco).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.2
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• pp.41-49
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• 2013

Objectives: The purpose of this study was to clarify the association between serum carcinoembryonic antigen (CEA) and type of work in the shipbuilding industry. Methods: 1,072 final study subjects were admitted to a general hospital from April through July 2010 for the purpose of medical examination. Data on general characteristics such as age, smoking history, alcohol history and exercise habits was gathered through structured self-administered questionnaires. Information on job factors was collected from a medical examination, by interview and through company personnel data. Serum CEA levels were measured after eight hours' fasting and were analyzed by a radioimmunoassay. Results: On univariate analysis, the mean serum CEA level was significantly higher among married (p=0.02), older age (p<0.01), longer work time (p<0.01), smokers (p<0.01), lower education (p<0.01), and indirect and direct exposure groups (p<0.01). On multiple regression analysis, serum CEA level was influenced by smoking (p=0.001), duration of work (p=0.019), and direct exposure group (p<0.001). However, among the direct exposure group, serum CEA level was not significantly different between welding, mounting, electro-device constructive work, grinding and cleaning, and painting. Conclusions: The goal of this research was to determine if there were differences between serum CEA levels according to occupational role among shipyard workers. The direct exposure group of shipyard workers had a relatively higher level of serum CEA than did the indirect exposure group and office workers, most likely due to occupational exposure.

• Journal of the Korean Vacuum Society
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• v.21 no.3
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• pp.158-163
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• 2012

In this work, we have fabricated the $TiO_2$ thin films on Si and glass, polymer insulator substrates as the self-cleaning coating of polymer insulator. $TiO_2$ films were deposited by RF magnetron sputtering method with $TiO_2$ ceramic target and $TiO_2$ films of 100 nm thickness were fabricated with various RF powers. We have investigated the optical and surface, and structural properties of $TiO_2$ films prepared with various RF powers. As a result, the value of the contact angle of $TiO_2$ thin film is increased with increasing RF power and the value of the rms surface roughness is increased. The transmittance is decreased with increasing RF power. These results indicate that the variation of the surface and optical properties of $TiO_2$ thin films is related to the sputtering effects by increasing RF power.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.443-450
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• 2008

Efficient use of low rank coals (LRC) have been investigated as a method to cope with recent high oil price. Among the coals used in industry, lignite and sub-bituminous coals are belong to the LRC, and have abundant deposit and are distributed worldwide, but high moisture contents and self ignition properties inhibits their utilization. In this paper, chemical coal cleaning to produce ash-free coal from LRC has been investigated. Two technologies, that is, UCC(Ultra Clean Coal) process removing ash from coal and Hyper Coal process extracting combustibles from coal were compared with. UCC process has merits of simple and reliable when it compared with Hyper Coal process, but the remaining ash contents werehigher than Hyper Coal. Hyper Coal has ash contents under the 200ppm when raw coal is treated with appropriate solvent and ion exchange materials to remove alkali materials in extracted solution. The ash-free coal which is similar grade with oil can be used as alternate oil in the industry, and also used as a high grade fuel for IGCC, IGFC and other advanced combustion technology.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.281-284
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• 2011

Recently, many drivers was the damage caused by similar oil product sales and gas station by not using quantitative gas. so, these damages is expected to rise damages by increasing these problem. By using similar oil products, caused damage in the fuel lines' working of lubrication and self-cleaning function for the occurred trouble in the part of the early obsolescence and the accumulation of impurities in the fuel lines, combustion rate due to the difference between retail gasoline engine, the burden of weight, Toxic substances in exhaust emissions, engine oil and unresolved issue is the chemical reaction can occur. to prevent these damages, using the system use in-vehicle state data with OBD-II protocol and measure quantitative gas and similar oil. In this paper, there implement similar oil identification and quantitative gas system through OBD-II scanner to provide WiFi communcation by using WinCe development Board.

• Korean journal of food and cookery science
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• v.25 no.3
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• pp.283-296
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• 2009

This study examined food safety management at preschool establishments in Daegu and Gyeongbuk province, to provide data that can be used for food safety improvements. Field assessments of 60 foodservice establishments were executed from July to October, 2007. Statistical analyses of the data were conducted using the SPSS package program (version 14.0 for windows). The results are summarized as follows: 93.3% of the preschool foodservices were self-operated, and 24.1% of the child care centers and 96.7% of the kindergartens had employed dietitians. According to the averaged food safety evaluation scores the kindergartens (80.73) had a significantly higher score than the child care centers (50.37), and the public centers (85.00) had a significantly higher score than the private centers (54.29). While the average score of facilities that employed dietitian (73.58) was significantly higher than that of facilities that did not employ a dietitian (52.65). In addition, the average score of facilities that served meals in a dining room (80.83) was significantly higher than that of facilities that served meals in a classroom (59.33). The highest scoring food safety items included verifying employee health inspection reports (1.87), utilizing non-municipal water and routinely cleaning and well-maintaining the water storage tank (1.85), and disposing small amounts of leftovers in a vat after serving (1.83). In contrast, the lowest scores were for physical separation of clean areas and unclean areas to prevent cross-contamination (0.52), and physical separation between staff and food material entry areas (0.62). In conclusion, the preschool foodservice evaluated in this study required improvements in food safety management, and many of the child care centers were in need of immediate attention. To improve food safety at these establishments, administrators should implement prerequisite food safety programs.

• The Journal of the Korean dental association
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• v.54 no.12
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• pp.1035-1044
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• 2016

Purpose : The purpose of this study was to compare the plaque removal effects of vacuum oral cleaner developed for the patients with limited mobility with those of manual toothbrushes and high pressure injection oral cleaner (dental water jet). Meterials and methods : Thirty human subjects were measured with Patient Hygiene Performance index (PHP index) and O'Leary index before and after the use of toothbrush, high pressure injection oral cleaner and vacuum oral cleaner. These three different oral hygiene methods were conducted with seven-day intermittence. Then the statistical analysis was carried out to define plaque removal rate of three different oral hygiene methods (${\alpha}=.05$). Results : According to the efficacy analysis of plaque removal before and after the oral cleaning using each of three methods, significant reduction in plaque after the treatment compared to the previous state when using toothbrush, high pressure injection oral cleaner, and vacuum oral cleaner was observed (P < 0.001). PHP index of tooth brushing was higher than that of the high pressure injection oral cleaner, while PHP index of vacuum oral cleaner did not show significant difference from either of the other two methods. There was no significance difference in O'Leary index among the three methods. Conclusion : Effect of plaque removal using the vacuum oral cleaner is comparable to that of manual tooth brush or high pressure injection oral cleaner, so it will be helpful for self-oral hygiene care of the patients with limited mobility.