• Journal of Radiation Protection and Research
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• 제16권1호
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• pp.15-24
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• 1991

CR-39 플라스틱 핵비적검출기를 라돈검출기로 내장한 멤브레인 필터컵(일명 : CR-39 라돈컵)을 이용하여 일부 국산건축자재의 라돈방출율을 측정하였다. 표준라듐선원을 이용한 라돈컵의 교정 실험을 수행하여 얻은 CR-39 검출기의 라돈검출인자는 $0.164{\pm}0.005(tracks \;cm^{-2}/Bq\;d\;m^{-3})$였으며 타 연구자들의 발표결과와 잘 일치하였다. 일부 건축자재(모래벽돌, 적벽돌, 화장석판, 콘크리트 덩어리, 건물바닥과 내벽)에 CR-39 라돈컵을 2개월 동안 기밀 부착하여 라돈방출율을 측정한 결과, 라돈방출율은 모래벽돌에서 평균$(75.0{\pm}5.5){\times}10^{-6}(Bq/m^2-s)$, 화강석판에서 $(6.8{\pm}2.9){\times}10^{-6}Bq/m^2-s)$로 10배정도의 차이를 보였으며, 모래벽돌>콘크리트바닥>콘크리트덩어리>건물벽>적벽돌>화강석 판의 순서를 보였다. 본 연구 결과, CR-39 라돈컵에 의해서도 건축자재의 라돈방출율을 효과적으로 측정할 수 있음이 입증하였다.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2370-2378
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• 2020

Building materials contribute significantly to the indoor radon and thoron levels. Therefore, parameters that influence the exhalation rates of radon and thoron from building material need to be analyzed closely. As a preliminary study, the effects of humidity on exhalation rates were measured using a system with an accumulation chamber and RAD7 detector for Korean brick, Korean soil, and Indonesian brick. Resulting doses to a person who resides in a room constructed from the building materials were assessed by UNSCEAR method for different air exchange rates. The measurements have revealed that Korean brick exhaled the highest radon and thoron while Indonesian brick exhaled the lowest thoron. Results showed that for a typical low dense material, radon and thoron exhalation rate will increase until reached its maximum at a certain value of humidity and will remain saturated above it. Analysis on concentration and effective dose showed that radon is strongly affected by air exchange rate (ACH). This is showed by about 66 times decrease of radon dose from 0.00 h^-1 to those of 0.50 h^-1 ACH and decrease by a factor of 2 from 0.50 h^-1 to those of 0.80 h^-1. In case of thoron, the ACH doesn't have significant effects on effective dose.

• 대한한의학회지
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• 제37권1호
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• pp.114-124
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• 2016

Objectives: The aim of this study is to find what effects both the posture of sitting and standing and the ratio of inhalation and exhalation (I/E) have on heart rate variability (HRV) Methods: We made two breathing sets with 4:6 or 6:4 ratios of I/E at 0.1 Hz of respiratory frequency and sitting or standing position. There was 20 minute-rest between sets. Each set include 5 minute-3 breathings as follows: 0.1Hz paced breath with sitting, usual breathing with standing and 0.1Hz paced breath with standing. Five minute-usual breathings with sitting as basal lines were exerted before and after these 3 breaths. Electrocardiogram-recording was exerted from 73 healthy participants (37 men and 36 women) who carried out two sets of breathings. Finally, HRV indices were analyzed of 62 participants (32 men and 30 women). Results: In 4:6 maintaining the same posture, SDNN were statistically increased, while mean heart rate(HR) were not changed. In 6:4, mean HR, SDNN were statistically increased. When changed from sitting to standing, in 4:6, SDNN were statistically decreased and mean HR was increased. However, in 6:4 during change of posture, SDNN were also statistically decreased and mean HR was statistically decreased. There was no statistical change of HF during 4:6 or 6:4 ratios of I/E moving from sitting to standing position. Conclusions: For increasing HRV, breathing in low respiratory rate with sitting was recommended regardless of ratio of I/E. In changing from sitting to standing, 4:6 may increase mean HR, and 6:4 may decrease mean HR.

• Physical Therapy Rehabilitation Science
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• 제10권4호
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• pp.438-443
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• 2021

Objective: The purpose of this study was to determine the effect of the difference in mask filters on the respiration rate of healthy people. Design: A randomized cross-over design. Methods: A total of 15 subjects were selected for this study (n=15). After filling out the Physical Activity Readiness Questionnaire, the selected participants abstained from caffeinated beverages and meals 30 minutes before and sat in a chair 10 minutes before stabilizing their breathing. Afterwards, the lung function test was performed 3 times for each mask, and the maximum value was used. The provided masks were Mask Free, Dental Mask, KF80, and KF94. Exhalation was measured for 6 seconds for each mask, and breathing was stabilized by repeating inhalation and exhalation until the next time. Results: In this study, the difference in respiratory function according to the mask type was statistically significant except for FEV1 and FVC (p<0.05). As a result of post-hoc analysis, FVC, FEV1, PEF, and FEF values were significantly lower than those of the control group not wearing a mask (p<0.05). When wearing KF94, FVC, FEV1, PEF25-25%, and FEF were significantly lower than when wearing a dental mask (p<0.05). When wearing a KF80 mask, it was significantly lower in FVC and FEV1 than when wearing a dental mask (p<0.05). In FEV1/FVC, the difference by mask type was not statistically significant (p<0.05), but it was lower than the spirometry standard of COPD patients (FEV1/FVC<0.7). Conclusions: As Now that wearing a mask is essential, it has been confirmed that the mask affects the respiratory rate.Therefore, in the case of healthy adults, it is recommended to rest after wearing a mask if attention deficit or headache occurs. People with low breathing capacity are recommended to have low-intensity activities and frequent rest periods after wearing a mask.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.36-38
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• 2006

In this study, two algorithms for detecting respiratory rate from Portable ECG device were presented. The first algorithms counts the number of ECG samples between R-R peaks, which varies according to respiratory states of patients, such as, exhalation and inhalation. The second algorithms detects the rate by measuring the size of R wave, which also varies according to the respiratory status of patient. These two algorithms were programmed to the laboratory developed ECG device and their usefulness was verified in laboratory environment.

• 대한음성학회지:말소리
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• 제49호
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• pp.135-144
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• 2004

In this paper, we make a study of classification normal from abnormal - normal, asthma through analysis of thoracic sound to take use thoracic sound detection system. Thoracic sound detection system has a function to store thoracic sound and analyze the data. The wave shape of thoracic sound is similar to noise and is systematically generated by inhalation and exhalation breathing, therefore, in this paper, to classify asthma sound in thoracic sound, we could discriminate between normal and abnormal case using level crossing rate(LCR) and spectrogram energy rate.

• 한국대기환경학회지
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• 제19권5호
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• pp.551-560
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• 2003

Particle deposition in human lungs was investigated theoretically by using asymmetric five-lobe lung model. The volumes of each of the five lobes were different, thereby forming an asymmetric lung structure. The tidal volume and flow rate of each lobe were scaled according to lobar volume. The total and regional deposition with various breathing patterns were calculated by means of tracking volume segments and accounting for particle loss during inhalation and exhalation. The deposition fractions were obtained for each airway generation and lung lobe, and dominant deposition mechanisms were investigated for different size particles. Results show that the tidal volume and flow rate have a characteristic influence on particle deposition. The total deposition fraction increases with an increase in tidal volume for all particle sizes. However, flow rate has dichotomous effects: a higher flow rate results in a sharp increase in deposition for large size particles, but decreases deposition for small size particles. Deposition distribution within the lung shifts proximally with higher flow rate whereas deposition peak shifts to the deeper lung region with larger tidal volume. Deposition fraction in each lobe was proportional to its volume. Among the three main deposition mechanisms, diffusion was dominant for particles < 0.5 ${\mu}{\textrm}{m}$ whereas sedimentation and impaction were most influential for larger size particles. Impaction was particularly dominant for particles> 8 ${\mu}{\textrm}{m}$. The results may prove to be useful for estimating deposition dose of inhaled pollutant particles at various breathing conditions.

• Perspectives in Nursing Science
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• 제14권2호
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• pp.64-69
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• 2017

Purpose: Breathing can be controlled either unconsciously or consciously. In Asian countries, various conscious breathing-control techniques have been practiced for many years to promote health and wellbeing. However, the exact mechanism underlying these techniques has not yet been established. The purpose of this study is to explore the physiological mechanism explaining how conscious breathing control could affect the autonomic nervous system, brain activity, and mental changes. Methods: The coupling phenomenon among breathing rhythm, heart rate variability, and brain waves was explored theoretically based on the research hypothesis and a review of the literature. Results: Respiratory sinus arrhythmia is a well-known phenomenon in which heart rate changes to become synchronized with breathing: inhalation increases heart rate and exhalation decreases it. HRV BFB training depends on conscious breathing control. During coherent sinusoidal heart rate changes, brain ${\alpha}$ waves could be enhanced. An increase in ${\alpha}$ waves was also found and the synchronicity between heart beat rhythm and brain wave became strengthened during meditation. Conclusion: In addition to the effect of emotion on breathing patterns, conscious breathing could change heart beat rhythms and brainwaves, and subsequently affect emotional status.

• 한국지하수토양환경학회지:지하수토양환경
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• 제9권1호
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• pp.12-27
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• 2004

본 연구에서는 벤젠을 대상으로 오염된 지하수를 생활용수로 사용했을 때 발생하는 실내오염도를 모사하고 실내에서 가능한 흡입, 섭취, 피부흡수와 같은 노출경로를 고려하여 노출시나리오를 자성하였다. 인체에 유입된 벤젠에 대하여 PBPK 모델을 이용하여 인체의 각 장기에 어떻게 분포하는지를 분석하였다. 결과에서 흡입과 섭취가 주요노출 경로였으며 남성이 여성보다 많은 호흡량으로 인해 보다 높은 노출속도를 유지하였다. 노출속도에 대한 피부흡수의 공헌도는 상대적으로 매우 작았다. 단기노출의 결과 오염물 노출에 대하여 SPT, RPT,간의 정맥혈 중 벤젠농도는 빠르게 증감하는 반면 지방의 경우는 느리게 반응하였고 많은 벤젠이 지방세포에 축적되어 정맥혈에는 적은 농도로 존재하였다. 장기간 노출에서 여성은 남성보다 전체적으로 2.1배 많은 벤젠을 체내에 축적하고 있는 것으로 나타났다. 장기간 노출에서 총유입벤젠의 98%가 호흡과 대사분해에 의해 제거되었다. 흡입경로는 벤젠이 호흡배출에 의해 69.8% 제거되었으며 섭취경로는 48.4%로 오염물이 유입되는 위치에 따라 각각의 제거기작의 공헌도가 다르게 나타났다. 본 연구의 결과는 실내오염에 따라 오염물이 체내에 흡수되고 분포ㆍ제거되는 현상을 이해하고 노출저감대책을 마련하는데 필요한 자료를 제공하고자 하였다.

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1282-1288
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• 2020

In the first study, the Radon emanation and radiological hazards associated with radionuclides in soil samples, collected from 9 various date palm farms located in 3 different districts in Saudi Arabia were determined through a high purity Germanium (HPGe) gamma-ray spectrometer. The estimated average values of Radon emanation coefficient and Radon mass exhalation rate for soil samples were 0.535 ± 0.016 and 50.063 ± 7.901 mBqkg^-1h^-1, respectively. The annual effective dose of radionuclides in all sampling locations was found to be lower than UNSCEAR's recommended level of 0.07 mSvy^-1 for soil in an outdoor environment. In the secondary study, gross α and gross β activities in soil and date palm pits samples were measured by a low background α/β counting system. Average values of gross α and gross β activities in soil and date palm pits samples were 5.761 ± 0.360 Bqkg^-1, 38.219 ± 8.619 Bqkg^-1 and 0.556 ± 0.142 Bqkg^-1, 24.266 ± 1.711 Bqkg^-1, respectively.