• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.12-19
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• 1994

An electrically heated experimental lumber dry kiln was retrofitted with a computer-based control system to control kiln conditions more precisely and monitor and record several kiln variables. Flat-sawn 2.5cm-thick Pinus densiflora boards were dried in constant temperature process(65$^{\circ}C$ & 50~60 %RH) and continuously rising temperature process, respectively. The average drying rate in continuously rising temperature process was 5.7 %/hr, which was above 3 times faster than that in constant temperature process. But, the average rate of case-hardening and moisture difference between shells and cores of boards dried in continuously rising temperature process were 82 % and 5.5 %, respectively, which were much larger than those of boards dried in constant temperature process.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.551-554
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• 2006

Inhibition of propellant temperature rising in liquid propulsion rocket using cryogenic fluid as a propellant is very important. Especially propellant temperature rising during stand-by after filling and pre-pressurization can bring into cavitation in turbo-pump. One of the method preventing propellant temperature rising in cryogenic feeding system is recirculating propellant through the loop composed of propellant tank, feed pipe, and recirculation pipe. The circulation of propellant is promoted through gas-lift effect by gas injection to lower position of recirculation pipe. In this experiment liquid oxygen and gas helium is used as propellant and injection gas. Under atmospheric and pressurized tank ullage condition, helium injection flow-rate is varied to observe the variation of recirculating flow-rate and propellant temperature in the feed pipe. There is appropriate helium injection flow-rate for gas-lift recirculation system.

• Journal of Ecology and Environment
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• v.34 no.2
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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.

• Corrosion Science and Technology
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• v.3 no.1
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• pp.14-19
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• 2004

Crack growth rate and threshold stress intensity factor for stress corrosion cracking(SCC), $K_{ISCC}$ were measured for type 403 stainless steel in 3,5% NaCl solution at room temperature and SCC was monitored by electrochemical noise technique during $K_{ISCC}$ testing. In rising load test, pits were formed at the tip of pre-crack for the pre-cracked compact tension specimen unlike in smooth round specimen in which only unstable pits were observed and hence immune to SCC. Micro-cracks were found to initiate from the pits in the former specimen, and initiation of micro-crack as well as macro-crack was detected by electrochemical noise technique in rising load $K_{ISCC}$ tests. Crack growth rate increased with increasing either displacement rate or stress intensity factor at crack initiation and was higher in rising load $K_{ISCC}$ test compared to constant load $K_{ISCC}$ test at given stress intensities.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.25-30
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• 2005

This experiment was carried out for the improvement of drying schedules for 50 mm-thick Japanese red pine (Pinus densiflora Sieb. et Zucc.) lumber. Drying rates were analyzed comparatively after drying to 15% of final moisture content through the applications of conventional kiln drying schedule, time schedule, continuously rising temperature schedule, and drying rate schedule. As results drying rate of 50 mm-thick red pine lumber was 0.53%/hr with conventional kiln drying schedule, 0.9%/hr with time schedule, 2.29%/hr with continuously rising temperature schedule, and 1.52%/hr with drying rate schedule, respectively.

• Journal of Ecology and Environment
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• v.30 no.1
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• pp.1-7
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• 2007

A model was developed to predict the effects of rising air temperature on net photosynthetic rate of Quercus mongolica stands at Mt. Paekcheok-san, Kangwon-do in South Korea. The PFD (Photon flux density) and air temperature were determined from weather data from the research site and the Daegwallyeong meteorological station and gas exchange or release responses of each tree component were measured. Using these data, we simulated the effects of increases in mean annual air temperatures above current conditions on annual $CO_2$ budget of Q. mongolica stands. If mean annual air temperature is increased by 0.5, 1.0, 1.5, 2.0, 2.5 or $3.0^{\circ}C$, annual net photosynthetic rate will be increased by 8.8, 12.8, 14.5, 12.6, 9.2 and 1.0 ton $CO_2\;ha^{-1}yr^{-1}$ respectively. Simulations indicate that changes in air temperature will have a major impact on gas exchange and release in Q. mongolica stands, resulting in a net increase in the rate of carbon fixation by standing crops.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.352-362
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• 2022

Photosynthesis and respiration of seagrasses are mainly controlled by water temperature. In this study, the photosynthetic physiology and respiratory changes of the Asian surfgrass Phyllospadix japonicus, which is mainly distributed on the eastern and southern coasts of Korea, were investigated in response to changing water temperature (5, 10, 15, 20, 25, and 30℃) by conducting mesocosm experiments. Photosynthetic parameters (maximum photosynthetic rate, P_max; compensation irradiance, I_c; and saturation irradiance, I_k) and respiration rate of surfgrass increased with rising water temperature, whereas photosynthetic efficiency (α) was fairly constant among the water temperature conditions. The P_max and I_k dramatically decreased under the highest water temperature condition (30℃), whereas the I_c and respiration rate increased continuously with the increasing water temperature. Ratios of maximum photosynthetic rates to respiration rates (P_max : R) were highest at 5℃ and declined markedly at higher temperatures with the lowest ratio at 30℃. The minimum requirement of H_sat (the daily period of irradiance-saturated photosynthesis) of P. japonicus was 2.5 hours at 5℃ and 10.6 hours at 30℃ for the positive carbon balance. Because longer H_sat was required for the positive carbon balance of P. japonicus under the increased water temperature, the rising water temperature should have negatively affected the growth, distribution, and survival of P. japonicus on the coast of Korea. Since the temperature in the temperate coastal waters is rising gradually due to global warming, the results of this study could provide insights into surfgrass responses to future severe sea warming and light attenuation.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.77-86
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• 2000

In order to observe the pattern forming of copper plate and chemical corrosion reaction, a study on the effect of the process parameters on the formation of micro-pattern by a photochemical etching of copper plate was carried out. The results are as follows : 1) Etching rate increases as the concentration of etchant increases under the regular condition of the temperature by the increasing of diffusion rate to surface. 2) Etching rate increases as the temperature of etchant increases by the fast acting of the material delivery of diffusion to surface under the regular condition of concentration. 3) It was found that etching speed increases as the material delivery of convection rising increased when the aeration speed of etchant increases. This result was from the fact acted by the material delivery of convection rising rather than material delivery of diffusion to the surface.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.707-714
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• 2003

Plasma Arc Curing(PAC) units operate at relatively high intensity and claimed to result in optimum properties of composite resin in a short curing time, so the interest of pediatric dentists about PAC units have been increased recently. But PAC units used for polymerizing restorative resins produce heat during operation. The purpose of this study was to evaluate temperature transmission through dentin of various depths using two types of PAC units(Flipo, Q-Lux plasma 100). The results from the present study can be summarized as follows : 1. When PAC be used continuously, temperature on tip was increased as curing times, and Q-Lux showed greater temperature rising(p<0.001). 2. Compared temperature transmission as dentin depth, temperature rising rate was decreased as dentin thickened(0.5, 1.0, 1.5, 2.0mm)(p<0.05). 3. Compared temperature transmission as resin depth, temperature rising rate was also decreased as resin thickened(1.0, 2.0mm)(p<0.05).

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.665-668
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• 2001

Generally, according to rising of atmospheric temperature, a consistency of concrete decreases, and a slump property of concrete is changed to be large. Also, in the strength development of concrete, the strength development rate of long-term age(28day) in comparison to strength of early age(7day) and the absolute compressive strength decreases. Accordingly, in this study, experiments about quality evaluation of concrete utilizing Ordinary Portland Cement is carried out. As a result of experiments, there were a conspicuous change in slump of concrete due to temperature increase. In conclusion, the rising of atmospheric temperature was very important factor in affecting the quality fluctuation of hot weather concrete.