• 상하수도학회지
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• 제21권1호
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• pp.37-46
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• 2007

A feasibility test was conducted to evaluate the addition of turbidity substance in a coagulation process to remove natural organic matters (NOM), the precursor of disinfection by-products (DBPs). The experimental water sources were synthetic water containing 5 mg/L of humic acid and 50 mg/L of NaHCO3 and drinking water resource of Ulsan city (S Dam water, D Dam water and Nak-Dong raw water). The examined turbidity substances were kaolin, acid clay, and modified clay (0.38 meq $NH_4{^+}-N/g$ clay). In Jar tests at different concentrations of the turbidity substances (5, 10, 15, 20, 30 mg/L) using the synthetic water, the turbidity substances improved the removal of turbidity, UV-254 absorbance and dissolved organic carbon (DOC) by 23.8-38.1%, 17.0-24.5% and 2.5-44.5%, respectively. The modified clay showed higher removal efficiencies than other substances. In Jar tests using the drinking water, 10 and 20 mg/L of modified clay enhanced the removal efficiencies of turbidity, UV-254 absorbance, DOC, trihalomethane formation potential (THMFP), and haloacetic acid formation potential (HAAFP) by 3.0~4.3%, 19.1~29.0%, 12~34.9%, 4.9~36.7%, and 1.6~30.2%, respectively.

• 한국압력기기공학회 논문집
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• 제13권1호
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• pp.75-83
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• 2017

This study investigated deformation behavior of major nuclear structural materials under cyclic loading conditions via cyclic stress-strain test. The cyclic stress-strain tests were conducted on SA312 TP316 stainless steel and SA508 Gr.3 Cl.1 low-alloy steel, which are used as materials for primary piping and reactor pressure vessel nozzle respectively, under cyclic load with constant strain amplitude and constant load amplitude at room temperature (RT) and $316^{\circ}C$. From the results of tests, the cyclic hardening and softening behavior, stabilized cyclic stress-strain behavior, and ratcheting behavior of both materials were investigated at both RT and $316^{\circ}C$. In addition, appropriate considerations for cyclic deformation behavior in the structural integrity evaluation of major nuclear components under excessive seismic condition were discussed.

• Environmental Analysis Health and Toxicology
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• 제12권3_4호
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• pp.43-54
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• 1997

Species, doses and routes extrapolation can be sucessfully carried out by using a physiologically-based pharmacokinetic (PBPK) approach. And PBPK approach to assess risk of hazardous chemicals is reasonable whatever the exposure scenarios are happened. Both partitioning coefficients of chemical between tissue and blood and enzymatic metabolic rate constants are key parameters to build up the PBPK model. In this study, we tried to estimate in vitro metabolic rate constants using a special apparatus instead to measure the in vivo constants which are used to PBPK simulation since the in vitro tests are less expensive and more convenient than in vivo tests. For the purpose, we designed and tested the new system to measure continuously the headspace concentration of VOC. The newly designed system is composed with a diffusion chamber which generates gaseous substrate, a reaction vessel with a recirculating pump to establish a closed system, an autbmatic sampler from a gas phase, a gas chromatography to analyze the headspace. In addition, a cold water condenser is attached between the reaction vessel and pump to reduce the content of gaseous moisture which interferes with chemical analysis. To validate the newly developed methodology, in vitro metabolic rate constants of trichloroethylene (TCE) as a prototype VOC were estimated by simulating observed results with an ACSL program. The simulated results are consistent to those estimated by the other research groups. This finding suggests that our newly designed closed system may be a useful apparatus to estimate in vitro metabolic rate constants for VOC.

• 한국구조물진단유지관리공학회 논문집
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• 제12권4호
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• pp.123-132
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• 2008

스톤컬럼 공법의 침하량 저감과 지지력 증진 효과를 파악하고자 연약한 준설매립 지반에 쇄석재료와 슬래그 재료를 이용하여 시험시공 후 지하수위계측 및 현장시험을 진행하였다. 현장실험 결과, 지지력 증진 및 침하량 저감 효과가 파악되었으며 상재하중 없이도 지하수위는 저하되는 양상을 보였다. 이는 스톤컬럼 공법이 밀도증가 측면과 더불어 액상화 저항에 우수함을 나타낸다. 일반적인 이론식을 이용하여 원지반 및 복합지반에 대한 침하량과 지지력 산정 결과, 스톤컬럼 공법은 2.7~5.7배의 지지력 증진 효과와 2~3.5배의 침하량 저감 효과가 있는 것으로 판단되었다.

• 접착 및 계면
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• 제5권2호
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• pp.5-14
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• 2004

Since flexible adhesives are used more and more in structural applications, designers should have a better understanding of its behaviour under various conditions as ultimate load, fatigue load, long-term load and environmental conditions. This paper focuses on long-term load conditions and its effect on flexible adhesives. The creep properties of both PU (PolyUrethane) and SMP (Silyl Modified Polymers) adhesives used for identical applications are considered. To investigate the creep behaviour tests under various conditions were done. The results of those tests are presented and compared. To evaluate these results an empirical method is proposed and discussed. An example illustrates the potential of this method. It is also shown that with use of a probabilistic calibration technique this method results into a simple rule, which can be used to calculate the creep for practical applications. For the studied adhesives, the creep performance of the SMP adhesive is shown to be of the same level or slightly better than of the two PU adhesives. In addition to this empirical method, the principles of a more complex theoretical based method are introduced. The potential of this method is illustrated and future research activities are drawn.

• 국제물리치료학회지
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• 제3권2호
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• pp.458-463
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• 2012

This study is to examine the effects of a feedback breathing device exercise and diaphragm breathing exercise on pulmonary functions of chronic strokes patients. The selection of 20 subjects was divided equally and placed into a experiment group and a control group and the intervention was applied four times per a week for five weeks. In each session, both groups received rehabilitative exercise treatment for 30 minutes, and a feedback breathing device exercise for 15 minutes. In addition, experimental group conducted a combination of diaphragm breathing exercise for 15 minutes. Prior to and after the experiment, patients' pulmonary functions were measured using a spirometer. The pulmonary function tests included FVC, FEV1, FEV1/FVC, PEF, VC, TV, IC, ERV, IRV. With respect to changes in the pulmonary functions of both groups, the experimental group significantly differed in FVC, FEV1, TV, ERV but did not in PEF, FEV1/FVC, VC, IRV. The control group did not significantly differ in any of the tests. There were significant differences in FEV1, FEV1/FVC, TV, ERV between the two groups, but no significant differences in FVC, PEF, FEV1/FVC, VC, IRV between them after the experiment. The experimental group, which conducted a combination of a feedback breathing device exercise and diaphragm breathing exercise, saw their respiratory ability increase more significantly than the control group. The breathing exercise was found to improve pulmonary function in chronic stroke patients.

• 가정간호학회지
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• 제23권1호
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• pp.25-33
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• 2016

Purpose: This study aimed to survey caregivers of patients with Neuromuscular Rare and Incurable Disease (NRID) using invasive home mechanical ventilator (HMV), in order to compare the incident rate of pneumonia by tracheal suction procedures used. Method: Participants were 99 family caregivers of NRID patients using HMV. Participants were given a questionnaire consisting of 12 demographic items, 10 items about disease and HMV related characteristics, 11 items about tracheal suction procedures, and 2 items about the incidence of pneumonia. Data were analyzed using chi-square tests and t-tests. Results: The items that predicted the incidence of pneumonia were "change of irrigation saline every suction" (p=.047), "use of aseptic catheter every suction" (p=.004), and "instillation of normal saline before suction" (p=.027). In addition, these items were 47.4%, 51.4%, and 38.8% respectively. Conclusion: Family members caring for NRID patients with invasive HMV should be educated about tracheal suction, especially the necessity of changing irrigation saline after every suction, using the aseptic catheter for every suction, and instillation of normal saline before suction. Medical personnel such as home care nurses should periodically check tracheal suction procedures, and re-educate family caregivers when necessary.

• 동아시아식생활학회지
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• 제25권2호
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• pp.223-233
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• 2015

The purpose of this study was to categorize dietary lifestyles and analyze intake behavior regarding beverages according to lifestyles of 276 university students in Yeungnam region. Frequency analysis, factor analysis, cluster analysis, reliability analysis, one-way analysis of variance, and ${\chi}^2$ tests were conducted using SPSS V.21.0. In the factor analysis, dietary lifestyles were categorized into one of five factors: health-seeking type, popularity-seeking type, safety-seeking type, economy-seeking type and convenience-seeking type. According to cluster analysis, respondents were divided into four groups: convenience-seeking group, wellbeing-seeking group, popularity-seeking group, and indifference group. Chi-square tests showed that there were significant differences in gender, grade, dwelling status, and monthly allowance according to the four dietary lifestyle groups. The level of dietary habits and percentage of correct answers related to beverages of the wellbeing-seeking group were highest among the four groups. The frequency of beverage intake was significantly different for carbonated drinks, milk and dairy products, and sport drinks according to dietary lifestyle groups. In addition, for beverage preference, there were significant differences in carbonated drinks, sport drinks, tea and functional drinks according to dietary lifestyle groups.

• Geomechanics and Engineering
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• 제9권1호
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• pp.1-14
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• 2015

Piezovibrocones have been developed to evaluate the liquefaction potential of onshore soils, but have not yet been utilized to evaluate the in-situ liquefaction behavior of offshore marine and volcanoclastic sediments. Two static and vibratory CPTu (Cone Penetration Tests) were performed at Tauranga Harbor, New Zealand. The lithology is known from nearby drillholes and the influence of vibration on different types of marine soils is evaluated using the reduction ratio (RR) calculated from static and vibratory CPTu. A sediment layer with high potential for liquefaction and one with a slight reaction to cyclic loading are identified. In addition to the reduction ratio, the liquefaction potential of sediment is analyzed using classic correlations for static CPTu data, but no liquefaction potential was determined. This points to an underestimation of liquefaction potential with the classic static CPTu correlations in marine soil. Results show that piezovibrocone tests are a sensitive tool for liquefaction analysis in offshore marine and volcanoclastic soil.

• 동아시아식생활학회지
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• 제22권2호
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• pp.305-314
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• 2012

This study examined awareness and information acquisition behavior regarding food hygiene and safety and information search behavior of college students. The sample was obtained from 284 students in Yeungnam region through a self-administered questionnaire. To describe characteristics of the respondents, frequency distributions were used. In addition, $t$ tests, analysis of variance and Duncan multiple range tests were conducted. Data were analyzed by SPSS Windows V.18.0. The results of the study were as follows: (1) most respondents were concerned about food hygiene and safety. They were mostly interested in the expiration date label on breads, milk/dairy products, fish products and meat products, and price of cookies. Many respondents answered that foods produced and distributed in Korea were not safe. The respondents were most worried about endocrine disruptors among various food risk factors. The respondents received information on food hygiene and safety from blogs, mini-homepages, or Kin-searches on the Internet, electronic media, and food labeling in decreasing order.