• 한국의학물리학회지:의학물리
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• 제28권3호
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• pp.83-91
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• 2017

In this work, we investigated the recently proposed phase-contrast x-ray imaging (PCXI) technique, the so-called single grid-based PCXI, which has great simplicity and minimal requirements on the setup alignment. It allows for imaging of smaller features and variations in the examined sample than conventional attenuation-based x-ray imaging with lower x-ray dose. We performed a systematic simulation using a simulation platform developed by us to investigate the image characteristics. We also performed a preliminary PCXI experiment using an established a table-top setup to demonstrate the performance of the simulation platform. The system consists of an x-ray tube ($50kV_p$, 5 mAs), a focused-linear grid (200-lines/inch), and a flat-panel detector ($48-{\mu}m$ pixel size). According to our results, the simulated contrast of phase images was much enhanced, compared to that of the absorption images. The scattering length scale estimated for a given simulation condition was about 117 nm. It was very similar, at least qualitatively, to the experimental contrast, which demonstrates the performance of the simulation platform. We also found that the level of the phase gradient of oriented structures strongly depended on the orientation of the structure relative to that of linear grids.

• 한국안광학회지
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• 제1권1호
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• pp.73-84
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• 1996

소아용 안경의 temple부분은 알맞는 탄력성이 있고 bridge부분은 충분한 견고성이 있어야 하여, 옥형 사이즈나 temple의 길이는 적어도 3-4종류가 있는 안경테로 하여야 한다. 또 pad는 높아와 폭 및 각도 조정이 가능한 것을 선택해야 하며, pad와 temple의 접촉에 대한 보정력이 충분한 것을 선택해야 한다. pad의 fitting은 비능부(鼻陵部)에 작용하는 안경중량의 크기가 압력에 비례하므로 pad의 전면(全面)이 비능부(鼻陵部)에 균일하게 접촉할 수 있도록 fitting해야 하며, pad는 접촉면이 넓은 것이 좋다. 렌즈의 선택시 주의할 점은 렌즈의 도수가 강해 질수록 안경 총중량에 차지하는 렌즈중량의 비율이 커지므로 무게는 될 수 있는대로 가벼운 것을 선택해야 하고, 최소직경 생지렌즈로 하는 것이 좋으며, 깨어지지않고, 안전성이 뛰어난 프라스틱 렌즈를 사용하는 것이 적합하다.

• 성인간호학회지
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• 제22권3호
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• pp.260-270
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• 2010

Purpose: The main question is systematic review of the published in Korea and foreign countries on warming therapy for surgical patients. Methods: The researchers searched at Medline, CINAHL, KERIS, Adult Nursing Association, Korean Society of Nursing Science, Korean Academy of fundamentals of Nursing, and National Assembly Library web site for the published on warming therapy for surgical patients from 1980 to 2008. Words for search were operation/surgery, warming, operation/surgery and warming. Studies were included randomized controlled trial, and there were no restrictions regarding operative phase and outcome measures. Results: 36 published researches that met the criteria were mostly published in foreign countries between 2000 and 2008 and focused on surgery with general anesthesia. Sample size ranged from 21 to 60 subjects, age range between 21 and 60 years of age. Thirty different warming therapies were reported, fifty-two different dependent variables. Outcome indicators included active external warming, intra-operative, and body temperature. 'Positive effects' and 'no effects' equaled. The most frequently reported 'positive effects' were body temperature, shivering, and acid-base balance. No effects were more likely to be heart rate, blood pressure, and hemodynamics. Conclusion: Many types of warming therapy, are reported in the literature with little information about the efficacy of each, many different dependant variables were studied. There were no consistent reports as to length of time used for warming procedures. Overall, the effects of warming therapy are inconsistent. And additional research must be down before any particular method of warming can be used with confidence as to its effectiveness. Attention must be made as to the research design, better measurement of the dependent variables. This review may serve as a base.

• 보건교육건강증진학회지
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• 제28권5호
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• pp.131-143
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• 2011

Objectives: This study is to develop a web-based prevention program of alcohol-related problem among university students and to examine its efficacy in changing drinking behaviors and reducing harms associated with alcohol use. Methods: An hour-length program was developed containing news paper articles, pictures, stories and questionnaires in a multimedia format such as flash, animation, and text. Survey data were analyzed to examine program efficacy from a convenient sample of 1,080 freshmen enrolled in a participating university. Results: Participation in the program has resulted in statistically significant changes in drinking behavior between pretest and follow-up, including reduction of frequency of drinking, heavy drinking, and intoxication, typical amount of drinking per occasion, and subjective norm of heavy drinking. Repeated ANOVA revealed significant increases in knowledge on alcohol related facts, including recommended drinking unit by WHO with substantial level of effect size and in making negative alcohol expectancy with very low effect size. Further studies are guaranteed with randomized controlled trial for the program effectiveness. Conclusions: A web-based prevention program of alcohol-related problems in this study was efficacious in changing drinking behavior, knowledge on alcohol-related fact, alcohol expectancy and subjective drinking norm.

• 공업화학
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• 제7권4호
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• pp.787-793
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• 1996

본 논문은 옵셋 잉크가 국내 신문고지의 탈묵에 미치는 영향을 조사하기 위해 국내신문 옵셋잉크의 조성분과, 그들 잉크로 옵셋 인쇄된 시료를 10, 30, 90, 180일 동안 열화시킨 후, 이들의 탈묵성을 비교하였다. 인쇄잉크의 조성분을 다르게 하여 인쇄한 시료는 열화기간이 증가될 수록 수율과 백색도가 감소되었다. 특히 아마인유의 첨가량이 많은 시료의 경우, 열화기간에 따라 많은 수율의 감소와 백색도의 저하를가져왔다. 따라서 아마인유의 첨가량은 탈묵에 결정적인 역할을 한다는 결론을 얻었다. 또한 로진변성페놀수지와 길소나이트가 포함된 시료는 열화과정을 통해 상대적으로 백색도의 감소가 있었다. 강도 측면에서 볼 경우, 열화기간에 따라 대체로 인장지수와 파열지수는 감소하였고, 인열지수는 증가했다. 그러나 아마인유만을 비이클 성분으로 사용한 시료의 경우 다른 시료에 비해 모든 강도가 낮았는데, 이것은 잉크와 섬유간의 강한 가교결합이 형성되어 초지 시 해리가 어렵기 때문이다.

• PNF and Movement
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• 제19권1호
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• pp.127-135
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• 2021

Purpose: The purpose of this study was to determine the effect of the side-bridge exercise on the thicknesses of the external and internal obliques, the transverse abdominis, and the erector spinae, which are some of the trunk muscles of healthy adult males and females. Methods: There were 30 subjects divided into two groups with 15 subjects in the modified side-bridge exercise group and 15 subjects in the bridge exercise group. The changes in each variable were analyzed before the exercise, after three weeks, and after six weeks of exercise using a two-way repeated analysis of variance. The significance level was set at 0.05. When there was any interaction between the time of measurement and each group, a paired t-test was conducted to find the difference within groups and an independent-sample t-test was conducted to find the difference between groups. The significance level for both tests was set at 0.01. Results: There was a significant difference in the external and internal obliques and the erector spinae according to changes over time and the interactions between the time and groups (p < 0.05). However, there was a significant difference in the transverse abdominis only according to the interaction between the length of times (p < 0.05). Conclusion: The study results indicated that the modified side-bridge exercise significantly increased the thickness of the external and internal obliques and the erector spinae. This suggests the usability of the exercise in lumbar stabilization exercises in future studies and clinical fields.

• 한국항공우주학회지
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• 제49권9호
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• pp.759-769
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• 2021

발사체 추진 시스템에서 Titanium Hydride Potassium Perchlorate (THPP)는 에너지를 인가받으면 gas를 발생시키는 pyrotechnic initiator로써 혹은 NASA Standard Initiator (NSI)의 supplement charge로써 흔히 사용되는 물질이다. 하지만 금속으로 이루어진 복합 화약이 오랫동안 보관이 되면 노화라는 문제에 직면하게 된다. 본 연구에서는 열분석 및 표면분석을 통하여 다양한 습도환경에서 노화된 THPP에 대하여 열역학적 특성의 변화를 확인하였고, 이를 바탕으로 THPP에 대한 전반적인 노화 메커니즘을 구축해내었다. 우선, THPP가 노화됨에 따라 산화제 표면의 균열빈도가 증가하고 길이가 길어졌는데, 이는 열·수분 노화가 공통적으로 산화제의 분해를 초래함을 보여준다. 이때 열 노화된 경우 Viton의 열화 현상이, 수분 노화된 경우 연료의 산화가 더욱 두드러졌다. 또한 실험을 통해 계산된 반응률에 대한 THPP의 화학반응인자의 경우 습도에 따라 크게 달라졌는데, 이는 수분이 THPP의 연소에 상당한 변화를 미쳐 결국에는 수명의 감소로 이어지게 될 것을 시사한다.

• 한국간담췌외과학회지
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• 제27권1호
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• pp.56-62
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• 2023

Backgrounds/Aims: Endoscopic retrograde cholangiopancreatography-guided gallbladder drainage (ERGD) is an alternative to percutaneous cholecystostomy (PTC) for hospitalized acute cholecystitis (AC) patients. Methods: We retrospectively analyzed propensity score matched (PSM) AC hospitalizations using the National Inpatient Sample database between 2016 and 2019 to compare the outcomes of ERGD and PTC. Results: After PSM, there were 3,360 AC hospitalizations, with 48.8% undergoing PTC and 51.2% undergoing ERGD. There was no difference in median length of stay between the PTC and ERGD cohorts (p = 0.110). There was a higher median hospitalization cost in the ERGD cohort, $62,562 (interquartile range [IQR] $40,707-97,978) compared to PTC, $40,413 (IQR $25,244-65,608; p < 0.001). The 30-day inpatient mortality was significantly lower in hospitalizations with ERGD compared to PTC (adjusted hazard ratio 0.16, 95% confidence interval [CI]: 0.1-0.41; p < 0.001). There was no difference in association with blood transfusions, acute renal failure, ileus, small bowel obstruction, and open cholecystectomy conversion (p > 0.05) between hospitalizations with ERGD and PTC. There was lower association of acute hypoxic respiratory failure (adjusted ratio [AOR] 0.46, 95% CI: 0.29-0.72; p = 0.001), hypovolemia (AOR 0.66, 95% CI: 0.49-0.82; p = 0.009) and higher association of lower gastrointestinal bleed (AOR 1.94, 95% CI: 1.48-2.54; p < 0.001) with ERGD compared to PTC. Conclusions: ERGD is a safer alternative to PTC in patients with AC. The risk complications are lower in ERGD compared to PTC but no difference exists based on mortality or conversion to open cholecystectomy.

• 가정과삶의질연구
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• 제30권6호
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• pp.23-37
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• 2012

Using data from the 2008 Korean Longitudinal Survey of Women and Families, this study investigated the income class differences in the modes, amount of time, and expenses for caring and educating a child in early childhood. The sample consisted of 1,849 households with a child aged 6 years or less. The major findings were as follows. First, the lower-income class was more likely to rely on child care centers and less likely to use services provided by kindergarten or private education. Their total amount of time required to provide care and education for their child was about 4 or 5 hours less than that of the other income classes; this result was due to the fact that they consumed less hours for home care, kindergarten, and private education. Second, we found there were more similarities than differences between middle-income and upper-income classes in the modes, amount of time, and expenses to care for and educate their young children; however, the middle-income class used less private education than the upper-income classes in terms of usage rate and length of time. Lastly, the other variables which were significantly related with the amount of time and expenses for child care and education included mother's employment, age of the child, and having siblings, and the family size. Based on the results, implications for public policy on early childhood care and education were suggested.

• 대한전자공학회논문지TC
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• 제44권2호
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• pp.55-61
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• 2007

본 논문에서는 곱의 상관방식과 차분상관방식의 OFDM 심벌 동기타이밍방식에 있어서 멀티패스 채널 지연프로필의 각 수신지연파에서 OFDM 심벌 동기타이밍으로 검출될 확률식을 나타내 보인다. 여러 가지 지연확산의 채널들에 대해 행해본 컴퓨터시뮬레이션의 결과 상관의 동기타이밍 검출방식에서는 진폭이 가장 큰 지연파의 선두에서 동기타이밍을 취할 확률이 높게 나타나는데 대하여 차분방식에서는 언제나 제 1수신지연파의 선두에서 동기타이밍을 취할 확률이 높게 나타나는 특성을 보여준다. 이러한 결과를 통하여 본 논문에서는 채널의 지연확산 길이에 관계없이 OFDM신호의 동기타이밍을 0점과 -1점 심벌 동기타이밍을 취하는 것에서 BER의 성능차이를 보여준다.