• The Korean Journal of Ecology
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• 제27권2호
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• pp.87-92
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• 2004

Soil respiration rate was measured from March to November 2003 using the KOH absorption method in Pinus densiflora, Quercus variabilis, Platycarya strobilacea stands in Jinju, Gyeongnam Province. Throughout the study period, average soil temperature and moisture content were 16.2$^{\circ}C$, 25.1% for P. densiflora stand, 17.1$^{\circ}C$, 24.3% for Q. variabilis stand, and 17.6$^{\circ}C$, 25.1% for P. strobilacea stand, respectively. The seasonal fluctuations of soil respiration rate increasing in summer and decreasing in winter, which there were strong positive correlations of soil respiration and soil temperature in all study stands. However, there were no significant correlations between soil moisture and soil respiration. Soil respiration rates throughout the study period ranged from 0.12 to 0.77 for P. densiflora stand, 0.23 to 1.37 for Q. valiabilis stand, and 0.30 to 1.47 g $CO_2\cdotm^{-2}\cdothr^{ -1}$ for P. strobilacea stand, respectively. Mean soil respiration rates in P. densiflora, Q. variabilis, P. strobilacea stands were 0.43, 0.80, and 0.90 g $CO_2\cdotm^{-2}\cdothr^{ -1}$, respectively. The Q$_{10}$ values were 2.38 for P. densiflora stand, 2.11 for Q. variabilis stand, and 2.07 for P. strobilacea stand. Annual total soil respiration was 24 for P. densiflora stand, 49.3 for Q. variabilis stand, and 55.3 t $CO_2\cdotha^{-1}\cdotyr^{ -1}$ for P. strobilacea stand, respectively.y.

• 한국기계가공학회지
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• 제18권4호
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• pp.100-108
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• 2019

In this paper, a new stacked element pressure sensor has proposed for heartbeat and respiration measurement. This device can be directly attached to an individual's chest; heartbeat and respiration are detected by the pulsatile vibration and deformation of the chest. A key feature of the device is the simultaneous measurement of heart rate and respiration. The structure of the sensor consists of two stacked elements, in which one element includes one polyvinylidene fluoride (PVDF) thin film bonded on polydimethylsiloxane (PDMS) substrate. In addition, for the measurement and signal processing, the electric circuit and the filter are simply constructed with an OP-amp, resistance, and a capacitor. One element (element1, PDMS) maximizes the respiration signal; the other (element2, PVDF) is used to measure heartbeat. Element1 and element2 had sensitivity of 0.163V/N and 0.209V/N, respectively, and element2 showed improved characteristics compared with element1 in response to force. Thus, element1 and element2 were optimized for measuring respiration heart rate, respectively. Through mechanical and vivo human tests, this sensor shows the great potential to optimize the signals of heartbeat and respiration compared with commercial devices. Moreover, the proposed sensor is flexible, light weight, and low cost. All of these characteristics illustrate an effective piezoelectric pressure sensor for heartbeat and respiration measurements.

• 한국전문물리치료학회지
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• 제12권4호
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• pp.26-32
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• 2005

This study was purposed to provide basic information on the correct application of a wheelchair's backrest angle by investigating the change in cardiopulmonary function according to backrest angle during propulsion. This study examined the effects of the wheelchair's backrest angle on the cardiopulmonary function by varying the angle to $0^{\circ}$, $10^{\circ}$ and $20^{\circ}$ with a propulsion velocity of 60 m/min. The experimental parameters were respiration rate, oxygen consumption rate and oxygen consumption rate/kg which were measured by a portable wireless oxygen consumption meter (COSMED, $K4b^2$). The results of the study were as follows: 1) There were no statistically significant differences in respiration rates due to changes in the wheelchair backrest angle (p>.05). 2) There were statistically significant differences in oxygen consumption rates due to changes in the wheelchair backrest angle (p<.05). 3) There were also statistically significant differences in the oxygen consumption rate/kg due to changes in the wheelchair backrest angle (p<.05). In conclusion, changes in the backrest angle of wheelchairs during propulsion influences oxygen consumption rates and heart rates, while respiration rates are not affected. Therefore, a training program for good seating and posture needs to be provided, and the wheelchair seating system should be equipped with the unadjustable-angle wheelchair to reduce the functional load on the cardiopulmonary system.

• Journal of Ecology and Environment
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• 제34권2호
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• pp.193-202
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• 2011

We studied temperature sensitivity characteristics of soil respiration during periods of rising and falling temperatures within a common temperature range. We measured soil respiration continuously through two periods (a period of falling temperature, from August 7, 2003 to October 13, 2003; and a period of rising temperature from May 2, 2004 to July 2, 2004) using an open-top chamber technique. A clear exponential relationship was observed between soil temperature and soil respiration rate during both periods. However, the effects of soil water content were not significant, because the humid monsoon climate prevented soil drought, which would otherwise have limited soil respiration. We analyzed temperature sensitivity using the $Q_{10}$ value and $R_{ref}$ (reference respiration at the average temperature for the observation period) and found that these values tended to be higher during the period of rising temperature than during the period of falling temperature. In the absence of an effect on soil water content, several other factors could explain this phenomenon. Here, we discuss the factors that control temperature sensitivity of soil respiration during periods of rising and falling temperature, such as root respiration, root growth, root exudates, and litter supply. We also discuss how the contribution of these factors may vary due to different growth states or due to the effects of the previous season, despite a similar temperature range.

• 대한인간공학회지
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• 제27권4호
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• pp.95-101
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• 2008

This research is to develop PPG filtering method for respiration measurement in U-Health Care system. Respiration rate was determined by filtering PPG and analyzing its spectrum. Optimal filter of PPG has been selected to get respiration by testing 120 sets of experiment data using 700 filtering cases. As a result, 2nd order Bessel-filter that used band-pass cutoff frequency at 0.175~0.4Hz with second order was good at developing respiration signal. Respiration signal in time domain could be continuously analyzed by converting frequency domain using spectrum analysis. 24 seconds has been found to be optimal time duration of collecting PPG data for determining respiration. Therefore, this study was successful of getting not only heart activity but also respiration by only PPG. Minimal invasive measurement obtaining multi-bio information by one sensor can be expected to apply to U-Health Care and human computer interaction.

• The Korean Journal of Ecology
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• 제26권5호
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• pp.289-296
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• 2003

The ecological process-based approach provides a detailed assessment of belowground compartment as one of the major compartment of carbon balance. Carbon net balance (NEP: net ecosystem production) in forest ecosystems by ecological process-based approach is determined by the balance between net primary production (NPP) of vegetation and heterotrophic respiration (HR) of soil (NEP=NPP-HR). Respiration due to soil heterotrophs is the difference between total soil respiration (SR) and root respiration (RR) (HR=SR-RR, NEP=NPP-(SR-RR)). If NEP is positive, it is a sink of carbon. This study assessed the forest carbon balance by ecological process-based approach included belowground compartment intensively. The case study in the Takayama Station, cool-temperate deciduous broad-leaved forest was reported. From the result, NEP was estimated approximately 1.2 t C $ha^{-1} yr^{-1}$ in 1996. Therefore, the study area as a whole was estimated to act as a sink of carbon. According to flux tower result, the net uptake rate of carbon was 1.1 t C $ha^{-1} yr^{-1}$.

• 한국산림과학회지
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• 제83권3호
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• pp.372-379
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• 1994

본 연구는 서로 다른 두가지 토양에서 천연갱신되어 자라고 있는 trembling aspen(Populus tremuloides Michx.) 임분의 수확이 토양미생물상 및 토양호흡률에 미치는 영향을 조사하며 토양호흡률이 토양미생물상 변이의 지표로 활용될 수 있는지에 대한 연구 결과이다. 다섯 가지의 수확처리(지상부 전체 임목수확, 겨울철 수확통로, 수확 잔재목 제거, 수확 잔재목 및 낙엽류 제거, 춘계 답압)를 1990년과 1991년 사이의 겨울 및 봄 사이에 시행하였고, 1991년 및 1992년의 2년간에 걸쳐 수확후 산림토양의 동태를 조사하였다. 각 임분의 토양형에 관계없이 토양호흡률은 수확후 약간 감소하거나 변동이 없었으나 미생물수는 수확후 2년동안 점차 증가하였다. 미생물수는 식질토양에서 보다 사질토양에서 보다 급속하고 지속적인 증가양상을 나타내었는데, 이것은 수확 결과 미생물 활성에 영향하는 토양의 이화학적 특성이 식질토양보다는 사질토양에서 큰 변화가 있었음을 시사한다. 그러나, 두가지 종류의 처리(세 수준의 유기물 제거 및 두 수준의 답압 처리)는, 두 지역 모두, 수확후 2년간의 미생물상이나 토양호흡률에 유의차를 나타내지 않았다. 본 연구의 대상임분이었던 trembling aspen은 수확후에도 뿌리의 활력이 떨어지지 않고 맹아발생을 위한 대사를 진행하여, 뿌리의 호흡과 미생물의 호흡을 포함하는 전체 토양 호흡에서 뿌리의 호흡이 차지하는 비율이 높은 결과를 낳아, 전체 토양호흡을 미생물의 활력도 변이의 지표로 활용하기 어려웠다.

• 감성과학
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• 제25권2호
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• pp.79-86
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• 2022

대기오염 등의 영향으로 실내 활동 시간이 증가하는 상황에서 뇌기능과 신체활동 측면에서 보다 건강한 실내 생활을 위한 다양한 방안에 대한 고려가 절실한 실정이다. 본 연구는 실내 산소의 농도와 호흡의 방법에 따라 인지능력과 생체신호에 어떤 영향을 미치는지에 대해 연구하여 보다 건강한 실내 일상생활을 제안하고자 한다. 건강한 성인 20명을 대상으로 공기 전달 시스템을 통해 공급된 공기를 산소마스크를 통해 흡입하도록 하였다. 호흡 방법과 산소농도에 따른 변화를 확인하기 위해 모든 피험자는 3가지 호흡(비강, 구강, 및 고농도 산소공급과 함께 구강 호흡)을 인지부하자극(눈 감은 휴식기, 눈 뜬 휴식기, 1-back 및 2-back 작업기억 과제) 별로 각각 수행하였다. 자극에 대한 반응시간, 정확도 및 생체신호를 측정하여 호흡에 따른 인지부하별 변화를 분석하였다. 그 결과, 3가지 호흡에서 모두 인지부하의 증가에 따라 심박동수는 유의하게 증가하면서 인지부하와 높은 상관성이 있는 생체신호임을 확인하였다. 또한 구강호흡에서는 분당 호흡 횟수가 인지부하증가에 따라 유의하게 증가하는 변화가 나타났으며, 인지활동 시 구강호흡에서 부족한 산소공급을 보완하기 위한 생체신호의 변화를 확인하게 되었다. 반면 고농도 산소공급과 함께 수행한 구강호흡에서는 비강호흡과 같이 분당 호흡 횟수의 유의한 변화는 없는 것으로 나타났다. 이는 고농도 산소공급이 구강호흡과 같이 비효율적인 산소 흡입이나 산소 농도가 부족한 환경에서 이를 보완해 주는 역할을 할 가능성이 있음을 시사한다. 본 연구 결과를 기반으로 후속 연구에서는 자율신경계 변화까지 분석하여 인지 뿐만 아니라 심리에 미치는 영향까지 종합적으로 규명하고자 한다.

• 원예과학기술지
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• 제29권6호
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• pp.583-591
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• 2011

'Formosa' plums were picked at three maturity stages according to skin redness, treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP at $10^{\circ}C$ for 24 h and then stored for 21 days at $10^{\circ}C$. Ethylene production, respiration rate, firmness, color, TSS, TA, and ethanol concentration were determined. Total phenolic content, total flavonoid content, and antioxidant capacity were determined periodically by separating the flesh from the peel. Ethylene production and respiration rate were strongly inhibited in all stages of the 1-MCP-treated fruit, while ethylene production dramatically increased in all stages of non-treated fruit until 11 days after harvest, after which it decreased until the end of the experiment. The respiration rate of the stored fruit increased for 11 days in stages 1 and 2 and for 7 days in stage 3 and decreased after. 1-MCP-treated fruit in all stages showed delay in fruit quality changes such as firmness, TA, skin color, and ethanol concentration, but non-treated fruit did not. Total phenolic contents, total flavonoid contents and antioxidant capacity of 'Formosa' plums were not affected by 1-MCP treatment or maturity stage. However, those values were higher in the peel than in the flesh.

• Food Science and Biotechnology
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• 제17권4호
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• pp.865-869
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• 2008

Effects of chitosan coating on respiration rate and internal gas composition of 'Fuji' apple and 'Satsuma' mandarin were investigated and compared to wax emulsions and two commercial coating materials. Chitosan coating reduced respiration rate significantly (p<0.05) in 'Fuji' apple and 'Satsuma' mandarin compared to uncoated and other coating materials. Chitosan coating on 'Fuji' apple showed the highest $CO_2$ and the lowest $O_2$ concentration in the internal gas composition at $5^{\circ}C$ but showed no differences compared to other coating materials at $20^{\circ}C$. 'Satsuma' mandarin showed significantly high $CO_2$ concentration in chitosan coating at $20^{\circ}C$ but there were not significant differences among coating materials in $CO_2$ and $O_2$ composition at $5^{\circ}C$.