• The Journal of Advanced Prosthodontics
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• 제13권3호
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• pp.144-151
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• 2021

PURPOSE. The purpose of this in vitro study was to investigate the wear resistance and surface roughness of three interim resin materials, which were subjected to chewing simulation. MATERIALS AND METHODS. Three interim resin materials were evaluated: (1) three-dimensional (3D) printed (digital light processing type), (2) computer-aided design and computer-aided manufacturing (CAD/CAM) milled, and (3) conventional polymethyl methacrylate interim resin materials. A total of 48 substrate specimens were prepared. The specimens were divided into two subgroups and subjected to 30,000 or 60,000 cycles of chewing simulation (n = 8). The wear volume loss and surface roughness of the materials were compared. Statistical analysis was performed using one-way analysis of variance and Tukey's post-hoc test (α=.05). RESULTS. The mean ± standard deviation values of wear volume loss (in mm³) against the metal abrader after 60,000 cycles were 0.10 ± 0.01 for the 3D printed resin, 0.21 ± 0.02 for the milled resin, and 0.44 ± 0.01 for the conventional resin. Statistically significant differences among volume losses were found in the order of 3D printed, milled, and conventional interim materials (P<.001). After 60,000 cycles of simulated chewing, the mean surface roughness (Ra; ㎛) values for 3D printed, milled, and conventional materials were 0.59 ± 0.06, 1.27 ± 0.49, and 1.64 ± 0.44, respectively. A significant difference was found in the Ra value between 3D printed and conventional materials (P=.01). CONCLUSION. The interim restorative materials for additive and subtractive manufacturing digital technologies exhibited less wear volume loss than the conventional interim resin. The 3D printed interim restorative material showed a smoother surface than the conventional interim material after simulated chewing.

• 한국터널지하공간학회 논문집
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• 제11권3호
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• pp.229-242
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• 2009

본 논문에서는 터널굴착으로 발생한 지표면에서의 최대 침하 및 수평변위와 총 침하부피량을 추정하기 위하여 서로 상이한 지층에서 다양한 깊이 및 직경, 서로 다른 시공조건(지반손실량)을 가진 터널에 대해 수치해석을 수행하였다. 수치해석 결과로부터 얻어진 지표면에서의 최대 침하량은 터널 굴착부 천단에서의 최대 침하량과 지층별, 터널직경 및 깊이, 시공조건(지반손실량)별로 비교되었으며, 또한 지표면에서의 최대 침하량은 지표면에서의 최대 수평변위량과도 비교하였다. 뿐만 아니라, 터널굴착부에서 발생한 지반손실량($V_L$)과 지표면에서 형성된 총 침하부피량($V_s$)을 지층 및 터널깊이와 직경을 달리하여 상호 비교하였다. 수치해석을 통해 얻어진 결과는 그 적용성과 타당성을 검증하기 위하여 기존 현장계측자료와의 비교가 수행되었으며, 이를 통해 본 연구의 수치해석 결과가 향후 터널굴착으로 발생된 주변 지반의 거동을 파악하고 분석하는 실무자료로서 활용될 수 있다는 것을 파악하였다.

• 자원리싸이클링
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• 제11권5호
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• pp.34-38
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• 2002

최근 전자기기의 경박단소화로 페라이트 코아의 사용주파수가 고주파화 되고 있다. Mn-Zn ferrites에서 전력손실은 hysteresis loss, eddy current loss, residual loss로 구성되어 있으며, 500 KHz 이상의 주파수 영역에서는 residual loss가 주도적인 손실을 나타낸다. Induction level이 50 mT 이하인 경우 전력손실은 주파수의 3승 이상에 비례하여 증가한다. 작은 grain과 치밀한 미세구조는 고주파 대역에서 eddy current loss를 감소시킬 뿐만 아니라 자속밀도를 증가시켜 Residual loss역시 억제한다. Resonance frequency와 static permeability를 곱한 값이 큰 시편일수록 고주파 영역에서 낮은 전력손실을 보인다.

• 대한간호학회지
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• 제27권3호
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• pp.683-693
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• 1997

Urinary incontinence is defined as the involuntary and inappropriate loss of urine to failure to emit normal responses as the bladder fills, or inability to reach the bathroom in sufficient time. This study was undertaken to estimate the incidence of urinary incontinence and to determine the correlates of urinary incontinence among women. Subjects of this survey consisted of 408 women, 26 to 83 years old in Incheon. The results of this study are as follows. 1. Of the subjects 50.7% reported urine loss once or twice per year and 28.5% reported incontinence on a regular basis at least once per month. 2. 40.5% of women reported small volume accidents of only 1 to 2 drops, 31.4% ; 1 t-spoon, 16.9% : 1 T-spoon, while 10.1% of women couldn't estimate the volume of urine loss. 3. The volume of urine loss was great enough to require a change of garment (undergarments or outer garments) in 73%. But only 3.8% of those used some type of pads. 4. 56.5% of incontinent women didn't talk about their urinary incontinence with other persons because they felt that urinary incontinence was shameful(38.4%), was not a disease(31.6%), was incurable in spite of treatment(27.4%) and was fearful of being uncured (2.6%). 5. Only 15.5% of urinary incontinent women had sought treatment. 6. The incidence of urinary incontinence was significantly higher in women who had more pariety and uterine-ovarian disease, older age, worrying about where toilets were when they visited new places or voiding anxiety, nocturia and frequency, but was significantly lower in women who had coffee intake. The incidence of urinary incontinence was not related to smoking and enuresis. The results indicate that urinary incontinence is common among young and middle-aged women. That few seek treatment for urinary incontinence suggests a need for more information about women's attitudes toward urinary incontinence and more attention to this problem by health care providers.

• 상하수도학회지
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• 제29권3호
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• pp.337-345
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• 2015

Two step rapid filter system as a pre-treatment for the injected water into aquifer storage and recovery (ASR) in Korea was developed to reduce physical blockage and secure the volume of the injected water. First, single rapid sand filters with three different media sizes (0.4~0.7, 0.7~1.0 and 1.0~1.4 mm) were tested. Only two sizes (0.4~0.7 and 0.7~1.0 mm) satisfied target turbidity, below 1.0 NTU. However, they showed the fast head loss. To prevent the fast head loss and secure the volume of the injected water, a rapid anthracite filter with roughing media size (2.0~3.4 mm) were installed before a single rapid sand filter. As results, both the target turbidity and reduction of head loss were achieved. It was determined that the media size for a rapid sand filter in two step rapid filter system (i.e. a rapid anthracite filter before a rapid sand filter) was 0.7~1.0 mm. In addition, the effects of coagulant doses on the removal of natural organic matter (NOM), which might cause a biological clogging, were preliminarily evaluated, and the values of $UV_{254}$, dissolved organic carbon (DOC) and SUVA were interpreted.

• 한방비만학회지
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• 제23권1호
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• pp.28-41
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• 2023

Objectives: This study was aimed to evaluate the hemodynamic feasibility using pulse parameters as a way to establish safe dose guidelines for herbal prescription containing Ephedra herb (Ephedra intermedia Schrenk & C.A.Mey) on weight loss, and to provide a foundation for developing evidence-based guidelines for clinical use. Methods: Forty-two volunteers were recruited to participate in a study examining the changes in pulse wave characteristics following the ingestion of Gambi-hwan, a herbal prescription containing ephedra, over a period of 4 weeks, and pulse wave measurements were taken before and after the administration. Pulse wave parameters were measured in this study using a 3-dimensional radial pulse tonometry device (DMP-Lifeplus). In addition, questionnaire, blood pressure, temperature, and body composition were also measured as secondary measures. Results: Fifteen minutes after administration of Gambi-hwan, the non-adverse event group (non-AE) exhibited a statistically significant increase in several power and pressure-related parameters, including h1, h5, systolic area, pulse area, and pulse width, while the AE group showed a trend of decreasing stroke volume and increasing Radial Augmentation Index (RAI), w, and w/t. After 4 weeks of administration, both groups exhibited significant changes in pulse rate, w/t, RAI, t3/t, stroke volume (SV), and stroke volume Index (SVI). Notably, there are significant differences between AE group and non-AE group in w/t, SV, and SVI. Conclusions: These findings suggest that pulse parameters may be a useful way to establish safe dosing guidelines for weight loss herbal prescription containing ephedra. Further research is needed to confirm these results and to develop evidence-based guidelines for clinical use.

• 한국병원경영학회지
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• 제26권3호
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• pp.13-27
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• 2021

Purpose: We examined the relationship between operating income and volume of medical services provided at general hospitals in 2018 according to characteristics of general hospitals and measured as operating income(net income) and volume(adjusted inpatient days) covered or non-covered by National Health Insurance(NHI). Methodology: Finance data from income statement reports in 212 general hospitals and the national health insurance claim data of these hospitals were used. The characteristics of the general hospital were divided into structural, operational, financial, and patient aspects. Operating income and volume were divided into covered and non-covered by NHI. Findings: The results showed high volume hospitals tended to be more profitable than low volume hospitals, especially in non-covered services. Operating income was more likely to be sensitive to non-covered services volume than to covered services volume. Practical Implications: It is necessary to understand the volume of services in non-covered, in order to obtain reliable cost information to be used for the fee schedule. Researches on small size hospitals(<160 beds) are needed, with a large variation in the volume of services and a strong tendency to compensate for the loss in the covered part in non-covered part.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.224-231
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• 2005

The ground excavation causes the deformation of the ground where the neighborhood structure is located. The ground deformation result in the vertical settlement of the neighborhood structure as well as the horizontal displacement of the temporary earth retaining structures. The decreased volume of the soil due to the ground settlement is defined as 'the ground loss quantity' or 'the ground loss'. When excavation is performed nearby existing structures, retaining walls should be designed and constructed to minimize the ground loss. Among various methods for reducing the ground loss, this study introduces the pre-loading method which has been recently developed. The reduction effect of the ground loss by pre-loading has been found to be larger as using a wall with relatively smaller rigidity.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.178-183
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• 2003

This paper deals with transmission loss characteristics of the panel type silencer to control low frequency noise. The panel type silencer is composed of many Helmholtz resonators by side branch. Each resonator has high transmission loss on the narrow band of its resonance frequency. Direct arrangement of the resonators increases mainly the magnitude of transmission loss. If we arrange the resonators in a row, the peak and band of transmission loss are increased. This makes the resonator array to have high transmission loss in the broader band. Using this idea, we design a silencer that has broader band characteristics and smaller volume.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.808-813
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• 2011

There are hundreds of thousands call center workers wearing acoustic device. However, researches and noise exposure measurements on the noise transmitted from acoustic devices have seldom been performed due to the difficulty of measurement and to the absence of the measuring method in Korea. The aim of this study is to set up management measures to protect hearing loss on the call operator by acquiring measurement data of noise transmitted from the headset Noise exposure measurements of 17 operators were performed in 7 call centers and Head and Torso Simulator method in compliance with the ISO Standard 11904-2 was used for the measurement of noise transmitted from the headset Sound pressure levels(SPL) transmitted from the headset were 73.2~86 dB(A). The operator exposed to the highest SPL set up his volume control at 9 which was the highest volume level. The volume control level, adjustable from 1 to 9, could be identified 12 out of 17 operators and the range of volume levels was 4.5~9. As a result of Pearson Correlation Analysis, the correlation between volume level and SPL transmitted from the headset showed high relation as significance at the 0.672 level(p<0.05). To protect hearing loss of call center operators, it is more practical and effective measure to limit the volume level below the noise exposure level, i.e. 85 dB(A), rather than to carry out noise monitoring considering cost-effective aspect.