• 한국주조공학회지
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• 제24권1호
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• pp.26-33
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• 2004

The pressure of the mold flux acting on the meniscus shell was investigated through the coupling analysis of heat transfer in the mold and fluid flow in the flux caused by the mold oscillation. Finite element method was employed to solve the conservation equation associated with appropriate boundary conditions. As reported by previous workers, the axial pressure is positive on the negative strip time and negative on the positive strip time. A maximum pressure is predicted toward the top of the meniscus shell which has the thin shell arid a maximum value is in proportion to the relative mold oscillation velocity. The relative mold oscillation velocity was changed by the effect of meniscus level fluctuation. Therefore the pressure of the mold flux acting on the meniscus shell was different each cycle of the mold oscillation due to the irregularity of relative mold oscillation velocity.

• 교육심리연구
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• 제31권3호
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• pp.389-408
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• 2017

이 연구는 대학생의 시간압박감과 자유재량시간이 성별에 따라 차이가 있는지와 주관적 안녕감과 어떤 관계가 있는지를 밝히는데 목적을 두고 있다. 이를 위하여 부산 경남지역의 대학생 493명을 대상으로 시간압박감, 자유재량시간, 주관적 안녕감(삶의 만족도, 긍정정서, 부정정서)검사를 실시하여 다음과 같은 결과를 도출하였다. 첫째, 대학생의 시간압박감, 긍정정서, 부정정서는 성별에 따라 유의미한 차이를 보였다. 시간압박감와 부정정서는 여자 대학생이 높은 것으로 나타났고, 긍정정서는 남자 대학생이 높은 것으로 나타났다. 하지만 대학생의 자유재량시간과 삶의 만족도는 성별에 따라 차이가 없는 것으로 나타났다. 둘째, 대학생의 시간압박감은 삶의 만족도와는 부적 상관을 가졌으나 부정정서와 정적 상관을 보였다. 대학생의 자유재량시간은 삶의 만족도와는 정적 상관을 가졌으나 부정정서와 부적 상관을 보였다. 하지만 대학생의 시간압박감과 자유재량시간은 긍정정서와 상관이 없는 것으로 나타났다. 셋째, 회귀분석 결과 대학생의 시간압박감은 이들의 삶의 만족도와 부정정서를 유의하게 설명하였으나, 자유재량시간은 통계적으로 유의한 설명력이 없었다. 이와 같은 연구결과는 대학생의 주관적 안녕감을 증진시키기 위해서는 자유재량시간을 늘이기 보다는 시간압박감을 낮출 필요가 있으며, 남녀의 차이를 고려할 필요가 있음을 시사한다.

• 중환자간호학회지
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• 제12권2호
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• pp.26-38
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• 2019

Purpose : The aims of this study were to identify the incidence of pressure ulcers and to compare the predictive validities of pressure ulcer risk assessment scales among trauma patients. Methods : This was a prospective observational study. A total of 155 patients admitted to a trauma intensive care unit in a university hospital were enrolled. The predictive validity of the Braden, Cubbin & Jackson, and Waterlow scales were assessed based on the sensitivity, specificity, positive and negative predictive values, and area under the receiver operating characteristic curve (AUC). Results : Of the patients, 14 (9.0%) subsequently developed pressure ulcers. The sensitivity, specificity, positive predictive values, and negative predictive values were 78.6%, 75.9%, 24.4%, and 97.3%, respectively, for the Braden scale (cut-off point of 12); 85.7%, 68.8%, 21.4%, and 98.0%, respectively, for the Cubbin & Jackson scale (cut-off point of 26); and 71.4%, 87.2%, 35.7%, and 96.9%, respectively, for the Waterlow scale (cut-off point of 18). The AUCs were 0.88 (Waterlow), 0.86 (Braden), and 0.85 (Cubbin & Jackson). Conclusion : The findings indicate that the predictive validity values of the Waterlow, Braden, and Cubbin & Jackson scales were similarly high. However, further studies need to also consider clinical usefulness of the scales.

• Journal of Sport and Applied Science
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• 제3권2호
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• pp.17-27
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• 2019

Purpose: This study is to conduct usability evaluations from the perspective of developing comfort-shoes for the middle-aged and elderly to identify key factors and derive implications for optimal comfort-shoes production. Research design, data, and methodology: A total of 10 middle-aged and elderly women in their 50s and 60s were selected as eligible for the rescue. For data collection, the study was conducted in a Gang Survey, where pre-explanations, shoes test, and interviews were conducted. The collected data were analyzed in a total of four stages. In step 1, the contents obtained through interviews with the subjects were recorded in text, organized and analyzed systematically, and in step 2, unnecessary vocabulary, sentences, and overlapping opinions were eliminated. In step 3, we classified areas around key functions and carried out categorization tasks. Finally, in Step 4, the results and implications of the study were derived by classifying each usability evaluation shoe as positive and negative text around categorized data. Results: There are a total of seven factors for comfort-shoes usability evaluation, which are categorized as cushion, fitting, stability, flexibility, lightweight, comfort, and pressure. Positive/negative factors for the derived usability evaluation factors were shown in the form of a positive-centered, negative-centered, and positive-mixed mix for each of the four products. Positive-focused products are VA products, which are seven times more positive than negative factors. Negative-centered products are CL and SA products, which are five times more negative than positive factors. Positive mixing was a CA product with a ratio of 1:1. Text-based usability evaluations allow us to proceed with analysis based on more scientific data rather than simply listening to opinions and judging by comments. Conclusions: The study discussed implications of developing comfort-shoes for middle-aged consumers and future directions were discussed.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권9호
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• pp.533-540
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• 2000

Lightning impulse $(1.2/44[\mus])$ and damped oscillating impulse $(Osc./44[\mus])$ : 0.83[MHz]) breakdown characteristics in sulphur-hexafluoride/nitrogen (SF6-N2) mixtures were investigated. The predischarge currents were observed to clarify the breakdown mechanism. th experiments were carried out under nonuniform electric fields disturbed by a needle-shaped protrusion whose length and diameter are 10[mm] and 1[mm] at total gas pressure up to 0.5[MPa] with nitrogen concentrations varying from 5 to 20[%] in the mixture. The electrical breakdowns of SF6-N2 mixtures for both the positive and negative polarities develop with steplike pulses in leader mechanism and the breakdown voltage -time (V-t) characteristics were affected by the space charge. The voltage-time curves for the negative oscillating impulse voltage were extended over the longer time range. The minimum breakdown voltages for the negative lightning and oscillating impulse voltage were higher than those for the positive ones. in particular the positive breakdown voltages were independent of the gas pressure.

• 한국정보시스템학회지:정보시스템연구
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• 제28권4호
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• pp.251-270
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• 2019

Purpose Unlike advertising through the traditional media targeting unspecified number of people, the base of mobile environment using smartphone has expanded so that many companies can classify prospective customers according to their purpose, thereby enabling efficient targeted marketing with low cost. Design/methodology/approach This study has investigated how can marketing strategy be influenced by the price promotion type (immediate discount/delayed discount) and message framing (positive/negative) according to time pressure (low/high). Hypotheses are set through the consideration of prospect theory, endowment effect, framing effect, regulatory-focus theory, and time-pressure theory. Findings The results and interpretation of this study are as follows. First, it was found that the influence of the delayed discount on the purchase intention was larger than the immediate discount. Second, negative/loss frame messages have more influence on purchase intention than positive/profit frame messages. Third, when the price promotion type is delayed discount, the effect of the promotion message on the purchase intention when it presented by negative/loss frame is greater than the other cases. The implication of this study is that it can be used as a basic data for establishing a strategy to maximize the effectiveness of promotions effectively considering potential buyers of mobile commerce environment.

• Neurospine
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• 제15권4호
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• pp.394-399
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• 2018

Subarachnoid pleural fistula (SPF) is an aberrant communication between the pleural cavity and subarachnoid space, resulting in uncontrolled cerebrospinal fluid drainage. The negative pressure of the pleural cavity creates a continuous suctioning effect, thereby impeding the spontaneous closure of these fistulas. Dural tears or punctures in cardiothoracic procedures, spinal operations, and trauma are known to cause such abnormal communications. Failure to recognize this entity may result in sudden neurological or respiratory complications. Hence, a high index of suspicion is required for early diagnosis and prompt management. Noninvasive positive pressure ventilation has been described to be effective in managing such fistulas, thus mitigating the high morbidity associated with exploratory surgery for primary repair. Herein, we describe the typical presentation of SPF and the clinical course, treatment, and follow-up of a patient who sustained SPF following anterior thoracic spinal surgery.

• 대한물리의학회지
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• 제14권3호
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• pp.47-53
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• 2019

PURPOSE: This study measured the external pressure on abdomen during maximal inspiration. The study determined the correlation between the diaphragmatic contraction pressure and the lung capacities to verify whether or not the measured pressure values can represent diaphragmatic contractility. METHODS: The study included 32 healthy subjects (16 males and 16 females). The researchers fabricated their own diaphragmatic pressure belt (DiP Belt) to measure DCP. DiP Belt device was fixed on the front of the abdomen and the diaphragmatic contractility was measured during maximal inspiration. The lung capacities were measured using a portable digital spirometer device (Pony Fx, COSMED, Italy). A digital spirometer is a device that is used to test the flow of air entering and exiting the lungs. RESULTS: DCP showed significant positive correlations with vital capacity (VC), inspiratory reserve volume (IRV) and inspiratory capacity (IC). Among values of lung capacities, IC showed especially strong positive correlations with the DCP (r =.714, p<.010). For the males, DCP showed significant positive correlations with IRV and IC, and DCP showed significant negative correlation with the expiratory reserve volume (ERV). For the females, DCP showed significant positive correlation with tidal volume (VT), but any significant correlation was not found with any of the other values of lung capacities. CONCLUSION: DCP showed high correlations with IRV and IC associated with inspiratory capacity. Therefore, The DiP Belt can be looked upon as a simple device that is very useful for measuring diaphragmatic contractility.

• 대한임상독성학회지
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• 제20권2호
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• pp.75-81
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• 2022

Purpose: This study sought to compare the characteristics of patients with pathogen-positive and negative cultures, and to investigate factors predicting pathogen-positive culture results in patients of acute poisoning with suspected aspiration. Methods: Consecutive patients with acute poisoning admitted to an intensive care unit between January 2016 and December 2018 were retrospectively studied. Respiratory specimens were collected from the enrolled patients at the time of the suspected aspiration. We compared the characteristics of patients with pathogen-positive and negative culture results and analyzed the causative pathogens. Results: Among the 526 patients, 325 showed no clinical features that could be attributed to aspiration, and 201 patients had clinical features suggestive of aspiration. Of these, 113 patients had pathogen-positive culture, 61 were negative, and the specimens of 27 patients contained poor-quality sputum. In univariate analysis, patients with a positive culture showed a longer time to culture from ingestion (p=0.01), faster heart rate (p=0.01), and higher partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO₂/FiO₂) (p=0.02) than patients with negative culture. Multivariate analysis demonstrated that PaO₂/FiO₂ (adjusted odd ratio, 1.005; 95% confidence interval [CI], 1.002-1.008; p=0.005) was a significant risk factor for pathogen-positive culture. The area under the receiver operating characteristic curve of PaO₂/FiO₂ was 0.591 (95% CI, 0.510-0.669, p=0.05). Gram-negative pathogens (GNPs) were predominant and at least one GNP was observed in 84 (73.3%) patients among those with pathogen positive culture. Conclusion: We failed to find any clinical factors associated with positive culture results. Antibiotics that cover GNPs could be considered when deciding the initial antibiotic regimen at the time of suspected aspiration.

• Bulletin of the Korean Chemical Society
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• 제5권3호
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• pp.112-117
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• 1984

The association constants (K) of 3,5,N-trimethyl pyridinium iodide in 95 volume percent ethanol-water mixed solvent were determined by a modified UV and conductance method at $25^{\circ},\;30{\circ},\;40{\circ}\;and\;50{\circ}C$ over the pressure range 1 to 2000 bars. The association process is enhanced with increasing pressure and decreasing temperature. From K values, we obtained the total partial molar volume change (${\Delta}V$) and some thermodynamic parameters. The electrostriction volume (${\Delta}V_{el}$) and intrinsic volume (${\Delta}V_{in}$) were also evaluated. The values of ${\Delta}V,\;{\Delta}V_{el},\;{\Delta}V_{in}$ are negative, negative and positive, respectively, and the absolute values of all these three decrease with increasing pressure and temperature. The ion-pair size (a) were varied 3 to 6 ${\AA}$, with pressure and temperature. The solvation number (n) decreased from 2 to 0.5 with increasing temperature.