• 대한물리의학회지
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• 제15권1호
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• pp.11-18
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• 2020

PURPOSE: This study was to investigate examined the differences in the autonomic nervous functions of elite female judo athletes according to their performance by measuring the heart rate variability (HRV). METHODS: Sixteen elite female judo players participated in this study. The participants were divided into a high performance and low performance group according to the results of their competitions. The HRV (mean heart rate, SDNN, RMSSD, TP, LF, HF, LF/HF ratio) was measured in the resting status. A t-test was used to compare the two groups, and bivariate logistic regression analysis was performed to determine the HRV elements that affect performance. The data were analyzed using IBM SPSS Statistics ver. 24.0 (IBM Co., Armonk, NY, USA). RESULTS: The mean heart rate was higher in the high performance group (72.88) than in the low performance group (64.75) (p=.049). The LF/HF ratio was higher in the high performance group (3.43) than in the low performance group (0.83), and the results were significant (p=.038). No HRV elements having a significant effect on the performance were observed. CONCLUSION: This study showed that the activity of the sympathetic nervous system was dominant in the high performance group in the resting status than in the low performance. The high performance group is believed to be in the overtraining status who experience more stress.

• 펄프종이기술
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• 제43권3호
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• pp.21-29
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• 2011

Recently, the use of recycled fibers was increased in order to replace the virgin pulp for low production cost and forest conservation. However, the recycled fibers decreases drainage rate, papermaking efficiency and product quality by short fibers and low wettability because of hornification. To overcome the limitation of low drainage rate, the technology of organic fillers were applied. Wooden fillers gave high bulk and stiffness of paper, but they reduced the strength of paper. In order to improve strength properties 4 types of strength additives were added and analyzed. Cationic starch, branched strength additive, linear wet strength additive, and linear dry strength additive were used. The drainage rate and paper properties such as bulk, air permeability and tensile strength were measured. As results of analysis, addition of branch type of strength agent such as C-starch was effective than linear type of strength agent in the drainage rate. Nevertheless there was no effect on the drainage rate by adding the pretreated wooden fillers. By adding the pretreated wooden fillers, bulk, air permeability and tensile strength of handsheets were improved with low dosage than non-pretreated fillers.

• 한국연소학회지
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• 제8권4호
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• pp.9-14
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• 2003

High temperature air combustion technology has been utilized by using preheated air over 1100 K and excessive exhaust gas recirculation. Numerical analysis was performed to investigate the combustion characteristics with high temperature deficient oxygen air combustion by adopting a counterflow as a model problem accounting for detailed chemical kinetics. Methane($CH_4$) was used as a test fuel and calculated oxidizer conditions were low temperature high oxygen (300K, $X_{O2}=0.21$) and high temperature low oxygen (1300K, $X_{O2}=0.04$) conditions. The latter case showed that the flame temperature is lower than the former case and its profile showed monotonic decrease from oxidizer to fuel side, without having local maximum flame temperature at high stretch rate. Also, heat release rate was one order lower and it has one peak profile because of low oxygen concentration and heat release rate integral is almost same for stretch rate. High temperature low oxygen air combustion shows low NO emission characteristics.

• The Korean Journal of Pain
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• 제4권1호
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• pp.51-55
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• 1991

There is a variety of therapeutic modality for herniated nucleus pulposus. Recently the low level laser has come into use for treatment for it. We treated two patients suffered from herniated nucleus pulposus of the central type of $L_{3,4}$ level, with He-Ne, $CO_2$ and Ga Al As laser simultaneously daily under hospitalization. In order to determine the efficacy of treatment, we used the "visual analogue scale" and its improvement rate. The results were as follows; Case I complained of gait disturbance, and hypoesthesia on the lateral side of the left lower leg, as and as low back pain. At the 15th day after treatment, VAS improvement rate was 40%, and the gait disturbance and hypoesthesia were markedly improved. 35th days after tratement, VAS improvement rate was 80%. Case II complained only of low back pain. At the 15th day after treatment, the VAS improvement rate was 68%, and at 20 days after treatment it was 84%. We sugsest that, using the low level laser for treatment of herniated nucleus pulposus increased the cartilage entrophism, and inhibitory effects of the inflammatory materials such as acid glycosaminoglycan by its anti-inflammatory and analgesic effects.

• 기본간호학회지
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• 제18권3호
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• pp.348-355
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• 2011

Purpose: This study was done to examine the effects of heat therapy on low back pain, blood pressure and pulse rate after percutaneous coronary intervention. Method: The participants in this study were 40 patients who were admitted after having percutaneous coronary intervention. The experimental group, 20 patients, had heat therapy and the control group, 20 patients, maintained a supine position for 12 hours after the intervention. Back pain (VAS), blood pressure and pulse rate were measured just after removal of the sheath, and at 2-hour intervals up to 6 hours. Data were analyzed using SPSS 15.0. Results: The experimental group had significantly lower VAS for low back pain (F=23.44, p=.001). However no significant differences were found between two groups for blood pressure and pulse rate. Conclusion: The findings indicate that heat therapy is effective in reducing low back pain in patients who have had percutaneous coronary intervention. Therefore, heat therapy could be used as nursing intervention percutaneous coronary intervention.

• Steel and Composite Structures
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• 재36권6호
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• pp.703-710
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• 2020

This paper presents numerical and theoretical investigations on the strain rate in steel-concrete composite (SC) panels under low-velocity impact of a hemispherical rigid body. Finite element analyses were performed on five specimens with different loading rates. The impact energy was kept constant to eliminate its influence by simultaneously altering the velocity and mass of the projectile. Results show that the strain rate in most parts of the specimens was low and its influence on bearing capacity and energy dissipation was limited in an average sense of space and time. Therefore, the strain rate effect can be ignored for the analyses of global deformation. However, the strain rate effect should be considered in local contact problems. Equations of the local strain and strain rate were theoretically derived.

• 한국약용작물학회지
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• 제11권4호
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• pp.284-288
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• 2003

This study was conducted to classify photosynthesis rate and changes of rutin content of Korean buckwheat (cv. Chunchon-jaerae and Yangjeul-memil) treated with salinity, UV-C and low temperature. In case of cv. Chunchon-jaerae and Yangjeul-memil, according to the salt stress, transpiration rate, stomatal conductance and photosynthesis rate were decreased. Both cultivars also showed decrease of transpiration rate and photosynthesis rate under the UV-C. Rutin contents within leaf and stem of cv. Yangjeul-memil were decreased when NaCl concentration was high. Rutin contents within leaf and stem of cv. Yangjeul-memil were generally decreased when the time laps under the UV-C stress. Rutin contents within leaf and stem of cv. Chunchon-jaerae was also generally decreased when the time laps under the low temperature stress.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.426-445
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• 2012

Conventional rate control (RC) schemes for H.264 video coding usually regulate output bit rate to match channel bandwidth by adjusting quantization parameter (QP) at fixed full frame rate, and the passive frame skipping to avoid buffer overflow usually occurs when scene changes or high motions exist in video sequences especially at low bit rate, which degrades spatial-temporal quality and causes jerky effect. In this paper, an active content adaptive frame skipping scheme is proposed instead of passive methods, which skips subjectively trivial frames by structural similarity (SSIM) measurement between the original frame and the interpolated frame via motion vector (MV) copy scheme. The saved bits from skipped frames are allocated to coded key ones to enhance their spatial quality, and the skipped frames are well recovered based on MV copy scheme from adjacent key ones at the decoder side to maintain constant frame rate. Experimental results show that the proposed active SSIM-based frameskip scheme acquires better and more consistent spatial-temporal quality both in objective (PSNR) and subjective (SSIM) sense with low complexity compared to classic fixed frame rate control method JVT-G012 and prior objective metric based frameskip method.

• 동력기계공학회지
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• 제4권4호
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• pp.41-47
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• 2000

Fatigue crack propagation rate and threshold characteristics of the SA516/70 steel which is used for the low temperature pressure vessels, were studied in the room temperature of $25^{\circ}C$ and low temperature ranges of $-10^{\circ}C,\;-30^{\circ}C,\;-60^{\circ}C\;and\;-80^{\circ}C$ with stress ratio of R=0.1. In the logarithmic relationship between the fatigue crack propagation rate($d{\alpha}/dN$) and stress intensity factor range ${\Delta}K$, the linear relationship was obtained up to $d{\alpha}/dN=4.425{\times}10^4mm/cycle$ in the same of room temperature, but in low temperature case, the relationship was extended to the range of low crack propagation rate. The fractured specimens were examined by SEM. Tested results showed that specimen failed at low temperature exhibit the quasi-cleavage fracture formation however considerable ductility proceed final fracture.

• Journal of Radiation Protection and Research
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• 제46권1호
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• pp.14-23
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• 2021

Background: For radiological protection and control, the International Commission on Radiological Protection (ICRP) provides the nominal risk coefficients related to radiation exposure, which can be extrapolated using the excess relative risk and excess absolute risk obtained from the Life Span Study of atomic bomb survivors in Hiroshima and Nagasaki with the dose and dose-rate effectiveness factor (DDREF). Materials and Methods: Since it is impossible to directly estimate the radiation risk at doses less than approximately 100 mSv only from epidemiological knowledge and data, support from radiation biology is absolutely imperative, and thus, several national and international bodies have advocated the importance of bridging knowledge between biology and epidemiology. Because of the accident at the Tokyo Electric Power Company (TEPCO)'s Fukushima Daiichi Nuclear Power Station in 2011, the exposure of the public to radiation has become a major concern and it was considered that the estimation of radiation risk should be more realistic to cope with the prevailing radiation exposure situation. Results and Discussion: To discuss the issues from wide aspects related to radiological protection, and to realize bridging knowledge between biology and epidemiology, we have established a research group to develop low-dose and low-dose-rate radiation risk estimation methodology, with the permission of the Japan Health Physics Society. Conclusion: The aim of the research group was to clarify the current situation and issues related to the risk estimation of low-dose and low-dose-rate radiation exposure from the viewpoints of different research fields, such as epidemiology, biology, modeling, and dosimetry, to identify a future strategy and roadmap to elucidate a more realistic estimation of risk against low-dose and low-dose-rate radiation exposure.