• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1400-1404
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• 2005

This paper presents the temperature control of aluminum plate by using Peltier element. Peltier effect is heat pumping phenomena by electric energy as one of the thermoelectric effect. So if current is charged to Peltier element, it absorbs heat from low temperature side and emits heat to high temperature side. In this experiment, Peltier element is used to control the temperature of small aluminum plate with current control and operating cooling fan only while cooling duration. Operating cooling fan only while cooling duration is proper to get more rapid heating and cooling duration. As a result of experiment, it takes about 100sec period to repeating temperature between $35^{\circ}C$ and $70^{\circ}C$ and about 80sec from $40^{\circ}C$ to $70^{\circ}C$ in ambient air temperature $25^{\circ}C$ and while operating cooling fan only in cooling duration. Future aim is to apply this temperature control method in actuating SMHA(special metal hydride actuator) which is applicable in Siver project acting in low frequency range by using Peltier element for heating and cooling.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.10
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• pp.759-765
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• 2012

In this paper, a temperature control for LED (light emitting diode) lamp using a cooling fan is studied. An efficient temperature control scheme for the LED lamp using the fan wind at the lowest sound noise is studied. For the study, after measurement of the minimum sound noise of the fan and related temperature of the LED lamp through tests, experiments on temperature control of the LED lamp using the fan with various size of heat sinks was performed. To reduce the fan sound noise, a method of reducing the operation time with optimal size of the heat sink was studied. Also, a control of LED lamps using RF communication was studied.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.11
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• pp.934-939
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• 2012

In this study, the performance validation of a PAO-AIR heat exchanger developed for the ECS(Environmental Control System) of a UAV(Unmanned Aerial Vehicle) has been carried out. The performance goals of a PAO-AIR heat exchanger were established by the system schematic analysis. And a heat exchanger to be met the ECS performance was developed by a detailed design and a precision manufacture. Using the developed heat exchanger, the experiment about pressure loss and effectiveness, overall heat transfer coefficient to prove the developed PAO-AIR heat exchanger performance in various conditions as well as a design point of heat exchanger was performed and the experimental results were analyzed. As the experimental results, the performance and characteristic of a PAO-AIR heat exchanger developed for the ECS of a UAV were analyzed and the development suitability was proved.

• Journal of Ginseng Research
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• v.43 no.1
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• pp.135-142
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• 2019

Background: Panax ginseng Meyer, known as Korean Red Ginseng (KRG), is one of the important age-old traditional herbs used in boosting libido and improving male fertility. In this study, the effects of Rg3-enriched KRG extract (KGC04P) on heat stress-induced testicular damage in experimental rats was evaluated. Methods: Male rats (Sprague-Dawley) were divided into four groups (n = 10): normal control (NC), heat-stressed control (HC), heat-stressed plus KGC04P-100 mg/kg (HK100), and heat-stressed plus KGC04P-200 mg/kg (HK200) groups. Starting 1 week prior to heat stress, animals were administered orally with KGC04P (100 and 200 mg/kg) mixed with a regular pellet diet and continued for 25 weeks. Heat stress was induced to HC, HK100, and HK200 groups by intermittently exposing the animals to high temperatures ($32{\pm}1^{\circ}C$, 2 h/day). After 6 months, animals were euthanized under general anesthesia with carbon dioxide and evaluated for various parameters in serum and testicular tissue by using Western blotting, biochemical kits, and reverse transcription-polymerase chain reaction. Results: Significant (p < 0.05) alterations in several parameters, such as body/organ weight, sperm kinematics, and lipid metabolism marker levels, in the serum and testis of rats were observed. Further, the expression of testicular antioxidant enzymes, inflammatory cytokines, sex hormonal receptors, and spermatogenesis-related genes were also affected significantly (p < 0.05) in the heat-stressed group. However, KGC04P prevented the heat stress-induced changes in rats significantly (p < 0.05) at both concentrations. Conclusion: KGC04P attenuated heat stress-induced testicular damage by a multifunctional approach and can be developed as an excellent therapeutic agent for hyperthermia-mediated male infertility.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.197-197
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• 2022

Wheat is highly susceptible to heat stress, which significantly reduces grain yield. In this study, we used RNA-seq technology to analyze the transcript expression at three different time-points after heat treatment in three cultivars differing in their susceptibility to heat stress: Jopum, Keumkang, and Olgeuru. A total of 11,751, 8850, and 14,711; 10,959,7946, and 14,205; and 22,895,13,060, and 19,408 differentially-expressed genes (log2 fold-change > 1 and FDR (padj) < 0.05) were identified in Jopum, Keumkang, and Olgeuru in the control vs. 6-h, in the control vs. 12-h, and in the 6-h vs. 12-h heat treatment, respectively. Functional enrichment analysis showed that the biological processes for DEGs, such as the cellular response to heat and oxidative stress-and including the removal of superoxide radicals and the positive regulation of superoxide dismutase activity-were significantly enriched among the three comparisons in all three cultivars. Furthermore, we investigated the differential expression patterns of reactive oxygen species (ROS)-scavenging enzymes, heat shock proteins, and heat-stress transcription factors using qRT-PCR to confirm the differences in gene expression among the three varieties under heat stress. This study contributes to a better understanding of the wheat heat-stress response at the early growth stage and the varietal differences in heat tolerancea.

• Particle and aerosol research
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• v.13 no.2
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• pp.65-77
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• 2017

In recent large-scale semiconductor manufacturing cleanrooms, the energy consumption in outdoor air conditioning (OAC) systems to heat, humidify, cool and dehumidify outdoor air(OA) represents about 40~50 % of the total cleanroom power consumption required to maintain cleanroom environment. Therefore, the assessment of energy consumption in outdoor air conditioning systems is essential for reducing the outdoor air conditioning load for a cleanroom. In the present study, an experiment with an outdoor air flow rate of $1,000m^3/h$ was conducted to compare the energy consumption in steam humidification, simple air washer, exhaust air heat recovery type air washer and dry cooling coil(DCC) return water heat recovery type air washer OAC systems. Besides, a numerical analysis was carried out to evaluate the annual energy consumption of the aforementioned four OAC systems. It was shown that the simple air washer, exhaust air heat recovery type air washer and DCC return water heat recovery type air washer OAC systems using water spray humidification were more energy-efficient than the steam humidification OAC system. Furthermore the DCC return water heat recovery type air washer OAC system was the most energy-efficient.

• Biomolecules & Therapeutics
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• v.5 no.3
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• pp.246-252
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• 1997

This study was performed to evaluate antiulcer effects of traditional folk medicines such as heat-treated acumen, halloysitum rubrum and os sepiae against stomach ulcer induced by acetic acid in Sprague-Dawley rats. Various pharmacological parameters were utilized to compare the antiulcer effects of aforementioned drugs based on the size of ulcer lesion, pepsin activity, free and total acidity, gastric secretory volume, and 5-HT (hydxoytrytamine) content. All folk medicines and ranitidine as control drus were shown to decrease ulcer lesion size after 5-day treatments, with the order of halloysitum rubrum, os sepiae, heat-treated acumen and ranitidine. All treated drugs except os sepiae inhibited the gastric volume as compared with that in the control group. Ranitidine most significantly inhibited the gastric volume. All the experimented drugs in this study lowered the gastric acidity. Halloysitum rubrum decreased it most remarkably, followed by ranitidine, os sepiae and heat-treated alumen after 5-day treatments. All used drugs alleviated the pepsin activity as compared with the control group, os sepiae being the highest then halloysitum rubrum, heat-treated alumen and ranitidine in turn. Heat-treated alumen and halloysitum rubrum showed mucin production to the great extent, and ranitidine had slight increasing effect thereon. At the end of observation period, all drugs except ranitidine increased 5-HT contents as compared to the normal group. From the above results, we could confirm the folk medicines such as heat-treated alumen, halloysitum rubrum and os sepiae have not only remarkable antiulcer effects but also preventing effects for the stomach ulcer recurrence, which suggest the experimented folk medicines could be developed as new antiulcer agents.

• International Journal of Air-Conditioning and Refrigeration
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• v.7
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• pp.22-32
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• 1999

A multi-type heat pump controls the mass flow rate of the working fluid to cope with variable heat loads when it is under dynamic load condition. This paper describes the exergy analysis associated with the unsteady response of a heat pump. First, a basic heat pump cycle is examined at a steady state to show the general trends of exergy variations in each process of the cycle. Entropy generation issue for the heat exchangers is discussed to optimize the heat pump cycle. Secondly, the performance of the inverter-driven heat pump is compared to that of the conventional one when the heat load is variable. Thirdly, the exergy destruction rate of the heat pump with On/Off operation is calculated by simulating the thermodynamic states of the working fluid in the condenser and the evaporator. The inefficiency of On/Off operation during the transient period is quantitatively described by the exergy analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.3
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• pp.123-129
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• 2010

The district heating users can be generally classified into two groups such as apartments and buildings. In consideration that the time zone of the maximum heat load for apartments is different from those of buildings during a day, the maximum heat supply range is presented. In case of the investigated area, the maximum heat supply is occurred at the ratio between apartments and buildings that is 65%：35%. Thus the heat supply range is increased as much as 15% if the time zone when the maximum heat load is occurred is considered.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.328-333
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• 2008

In order to control indoor air quality and save energy, it is needed to install a suitable heat exchanger for heat recovery. A plastic heat exchanger have many advantages and can recover $50{\sim}80%$ of the temperature difference between supply and exhaust air. The purpose of this research is to evaluate the performance of plastic heat exchanger with different shapes. Pressure drop and heat transfer characteristics of plastic heat exchangers are investigated for various velocities.