• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.1
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• pp.1-4
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• 1978

The change of soluble protein components in leaf discoloration of rice plant was investigated in the Growth Cabinet with various temperature conditions. The ratio between high molecular soluble protein and low molecular soluble protein was high under high temperature condition, while low under low temperature condition, and also lower in Indica type varieties than Japonica type variety.

• Journal of Welding and Joining
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• v.18 no.4
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• pp.96-103
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• 2000

This study investigated the effects of bonding temperature and bonding atmosphere on high temperature mechanical properties of transient liquid phase(TLP) bonded joints of heat resistant alloy using MBF-50 insert metal. Specimens were bonded at 1,423~1,468K for 600s. Microconstituents of {TEX}$Cr_{7}(C,B)_{3}${/TEX}were formed in the bonded region when the bonding temperature was low. The amount of microcostituents in the bonded layer decreased with increasing the bonding temperature, and the microconstituents in the bonded layer disappeared at the bonding temperature above 1,468K. The tensile strength of the joints at elevated temperatures increased with the increase the bonding temperature and was the same level as one of the base metal in the bonding temperature over 1,453K. Microstructure and alloying element distributions of the bonded region bonded in Ar and $N_2$atmosphere were similar to those of the bonded in vacuum. The creep rupture strength and rupture lives of joints were almost identical to those of base metal.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.325-335
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• 1992

In this work, direct contact 4-stage fluidized bed heat exchanger is experimentally studied to develop a new type of heat exchanger which recovers the energy contained in the high temperature waste gas exhausted from the industrial furnaces. A sand is used as a heat transfer medium in this experiment. To determine the optimum operating condition, 11 different perforated plates which have a different free area ratio with different hole diameter are used in the experiment. From the room temperature experiment, the pressure drop which is caused by fluidized bed formation is observed. The high temperature experiment is carried out to seek the optimum operating condition of high heat efficiency at low heat exchanger operation cost. The results of experiment are as following. The pressure drop in the high temperature condition can be predicted from the results of the room temperature experiment. And Nusselt number becomes smaller due to the increased interference between sand particles as Reynolds number increases when the dilute phase fluidized beds are formed in nigh temperature condition. But heat transfer amount through the total sand surface area become larger due to the large resident amount of sand. Considering the heat transfer amount and the heat exchanger operation cost, perforated plates which have either a 30% or 35% of free area ratio with 15mm of hole diameter are best fitted for our goal of this work. The values of .phi. which is a dimensionless number representing the absorption heat amount per unit sand rate are in the range from 0.4 to 0.5, when Reynolds number of waste gas ranges from 25-30 with these perforated plates.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.59-60
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• 2015

In this study, stress-strain, thermal expansion strain, total strain and high temperature creep strain of ultra-high-strength concrete with compressive strengths of 80, 130, and 180MPa were experimentally evaluated considering elevated temperature and loading condition. Also, transient creep strain has been calculated by using the results of experiment. Experimental coefficient K was proposed with application of non-steady state creep model. It is considered that the experimental results of this study could be baseline data for deformation behavior analysis of ultra-high-strength concrete.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.89.1-89.1
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• 2011

The influence of potential and humidity on the electrochemical carbon corrosion in high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs) is investigated by measuring $CO_2$ emission at different potentials for 30 min using on-line mass spectrometry. These results are compared with low tempterature polymer electrolyte membrane fuel cells(LT-PEMFCs) operated at lower temperature and higher humidity condition. Although the HT-PEMFC is operated at non humidified condition, the emitted $CO_2$ in the condition of HT-PEMFC is more than LT-PEMFC at the same potential in carbon corrosion test. Thus, carbon corrosion shows a stronger positive correlation with the cell temperature. In addition, the presence of a little amount of water activate electrochemical carbon corrosion considerably in HT-PEMFC. With increased carbon corrosion, changes in fuel cell electrochemical characteristics become more noticeable and thereby indicate that such corrosion considerably affects fuel cell durability.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.553-556
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• 2009

In this study, ignition tests of a gas turbine combustor were performed to evaluate an ignition loop at low temperature condition. An experimental setup was constructed to simulate low temperature condition with a heat exchanger using dry ice as a coolant. Various low temperature conditions could be created by controlling the amount of air though the heat exchanger. The results showed that ignition limit decreased with air temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.3
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• pp.163-170
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• 2016

Heading time is important element for yield and quality in crops. Among day length and temperature which influence on heading, temperature effect has not been investigated well. To investigate temperature effect on heading, heading date and plant growth characters were checked under the low and high temperature conditions in short day length. Analyzing heading date of six Korean varieties under the high and low temperature condition, heading date of varieties were delayed under low temperature. In the low temperature condition, dry weight and area of leaf were reduced. Varieties showing more delay of heading under low temperature also showed more reduction in leaf area. After selecting three varieties showing significant difference in leaf growth and heading date under different temperature conditions, nutrient contents of plant were analyzed. Nitrogen content was reduced in leaf and shoot under the low temperature condition. OsNRT2.3, nitrate transporter, was significantly down regulated in varieties showing more heading delay. Available phosphate content was decreased in leaf, but increased in shoot due to reduction of phosphate mobility. OsPT1, phosphate transporter regulating phosphate uptake, was more down regulated in varieties showing more heading delay. OsPT6, phosphate transporter regulating phosphate transport in plant, was also significantly down regulated in those varieties. With these data, we expected that active nitrogen and available phosphate uptake and transport in plant would increase leaf growth then might reduce heading delay under the low temperature condition.

• Journal of Environmental Science International
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• v.28 no.1
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• pp.147-158
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• 2019

In this study, we investigated the influences of abnormal high temperature on growth, yield and physiologically active substances of the strawberry. General strawberry cultivars in the $20^{\circ}C$ growth condition showed much better growth of leaf number, length, diameter along with plant height, compared with those in $22.5^{\circ}C$ or $25^{\circ}C$. But the cultivars of both 'Sulhyang' and 'Mehyang' showed good growth and development at $25^{\circ}C$ with the roots showing great growth at $20^{\circ}C$. The quality and yield of the strawberry were best in the $20^{\circ}C$ growth condition, but the merchantability deteriorated in the $25^{\circ}C$ high temperature condition. As for the content of the physiologically active substances of the strawberry, it increased at $20^{\circ}C$, the optimum growth temperature, but decreased at $25^{\circ}C$. The physiologically active substances in the strawberry differed among the cultivars, the contents of cyanidin-3-glucoside, cinchonine, ellagic acid and cinnamic acid higher in the 'Mehyang', whereas the content of fisetin is higher in the 'Sulhyang' cultivar.Consequentially, the high temperature in summer has a negative effect on the physiological active ingredients of the strawberry, which was increased in the strawberry cultivated at proper temperature, and high quality strawberry production was possible.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.41-46
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• 2003

The important problem in high speed spindles is to reduce and minimize the thermal effect by motor and bail bearings. Thermal characteristics according to the bearing pre-load and cooling condition are studied for the test spindl with grease lubrication and high frequency motor. Bearing and motor we main heat generation, and heat generation by ball bearings as a function of load, viscosity and gyroscopic moment effect are considered. Temperature distribution and thermal displacement according to the speed of spindle are measured by thermocouple and gap sensor. The results show that the fitting pre-load and cooling temperature are very effective to minimize the thermal effect by motor an ball bearings.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.45-59
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• 2010

It is well established fact that under tropical condition, unlike polyvoltines, bivoltines are more vulnerable to various stresses i.e. hot climatic conditions of tropics, poor leaf quality and improper management during summer which are not conducive for bivoltine rearing. Therefore, attempt has been made in this study to develop promising bivoltine breeds tolerant to high temperature and high humidity conditions of the tropics. In the present study, by utilizing temperature tolerant breeds six breeding lines were made and at every generation the 5th instar larvae were exposed to high temperature and high humidity and the survived ones were back crossed with the breeds moderately tolerant to diseases were made to improve the quantitative traits. From F6 generations, alternate rearing in normal temperature and high temperature were conducted. At the end of F12 generation, it was possible to isolate three dumbbell breeds viz., HH8, HH10 and HH12 with improvement in quantitative traits. The methodologies followed for the development are discussed.