• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.2
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• pp.73-81
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• 2004

Effects of ambient and elevated $\textrm{CO}_2$ and high temperature, and their interactions with zero and applied nitrogen supply (NN-no nitrogen and AN-applied nitrogen) were studied on soybean (Glycine max L.) in 2001. In this experiment, elevated $\textrm{CO}_2$ (650 $\mu\textrm{mol}.\textrm{mol}^{-1}$) and temperature (+$5^{\circ}$) increased total dry mass at final harvest by 125% and 119% and seed weight per plant by 57% and 105% for NN and AN plants, respectively. Although the influence of temperature and temperature x $\textrm{CO}_2$ were not significant, the influences of $\textrm{CO}_2$ concentration and temperature x $\textrm{CO}_2$ concentration were significant on total dry weight and seed weight, respectively. In particular, seed weight per plant was increased, while weight per one hundred seed weight was decreased with elevated $\textrm{CO}_2$ and temperature. The N supply increased biomass and seed weight per soybean plants. The results of this study suggest that the long-term adaptation of soybean growth at an elevated $\textrm{CO}_2$ concentration and high temperature might potentially result in a increase in dry matter production and yield.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.4
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• pp.459-467
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• 2021

In the majority of countries, the upper limit of buffer temperature in a repository is set to below 100℃ due to the possible illitization. This smectite-to-illite transformation is expected to be detrimental to the swelling functions of the buffer. However, if the upper limit is increased while preventing illitization, the disposal density and cost-effectiveness for the repository will dramatically increase. Thus, understanding the characteristics and creating a database related to the buffer under the elevated temperature conditions is crucial. In this study, a strategy to investigate the bentonite found in Korea under the elevated temperatures from a mineral transformation and radionuclides retardation perspective was proposed. Certain long-term hydrothermal reactions generated the bentonite samples that were utilized for the investigation of their mineral transformation and radionuclide retardation characteristics. The bentonite samples are expected to be studied using in-situ synchrotron-based X-Ray Diffraction (XRD) technique to determine the smectite-to-illite transformation. Simultaneously, the 'high-temperature and high-pressure mineral alteration measurement system' based on the Diamond Anvil Cell (DAC) will control and provide the elevated temperature and pressure conditions during the measurements. The kinetic models, including the Huang and Cuadros model, are expected to predict the time and manner in which the illitization will become detrimental to the performance and safety of the repository. The sorption reactions planned for the bentonite samples to evaluate the effects on retardation will provide the information required to expand the current knowledge of repository optimization.

• Journal of Korean Society of Steel Construction
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• v.28 no.4
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• pp.253-261
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• 2016

In order to evaluate compressive strength of centrally-loaded steel column at elevated temperature, new FE analysis techniques and assumptions of model were applied in this study. It also includes comparison with the existing studies, and a new design equation for centrally-loaded steel column at elevated temperature was proposed. The proposed equation was the most accurate of the three design equations(EC3, AISC, proposed equation) when comparing with the coefficient of determination on the simulated results and test results.

• Electrical & Electronic Materials
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• v.11 no.11
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• pp.22-27
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• 1998

We have investigated the effect of an ion shower doping of the laser annealed poly-Si films at an elevated substrate temperatures. The substrate temperature was varied from room temperature to 300$^{\circ}C$ when the poly-Si film was doped with phosphorus by a non-mass-separated ion shower. Optical, structural, and electrical characterizations have been performed in order to study the effect of the ion showering doping. The sheet resistance of the doped poly-Si films was decreased from7${\times}$106 $\Omega$/$\square$ to 700 $\Omega$/$\square$ when the substrate temperature was increased from room temperature to 300$^{\circ}C$. This low sheet resistance is due to the fact that the doped film doesn't become amorphous but remains in the polycrystalline phase. The mildly elevated substrate temperature appears to reduce ion damages incurred in poly-Si films during ion-shower doping. Using the ion-shower doping at 250$^{\circ}C$, the field effect mobility of 120 $\textrm{cm}^2$/(v$.$s) has been obtained for the n-channel poly-Si TFTs.

• Journal of the Korean Ceramic Society
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• v.36 no.1
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• pp.15-20
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• 1999

Elevated temperature static fatigue behavior of silicon has been investigated by stress intensity/life test method. Static fatigue crack growth rate increase with the increase of temperature. Such tendency is found to be mainly related to the decrease of fracture toughness with the increase of temperature. That is, when static fatigue crack growth rate, da/dt is expressed by da/dt=AK1m, a constant A is a function of fracture toughness Kc and the exponent m is a constant which is independent of temperature or Kc. However, in the case of high temperature that glass phase is softened, the crack growth rate is found to be deviated from the above relation. This reason is, thus, discussed.

• International Journal of High-Rise Buildings
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• v.7 no.4
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• pp.287-298
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• 2018

High strength steels have been widely applied in recent years due to high strength and good working performance. When subjected to fire conditions, the strength and elastic modulus of high strength steels deteriorate significantly and hence the load bearing capacity of structures reduces at elevated temperatures. The reduction factors of mechanical properties of high strength steels are quite different from mild steels. Therefore, the fire design methods deduced from mild steel structures are not applicable to high strength steel structures. In recent ten years, the first author of this paper has carried out a lot of fundamental research on fire behavior of high strength steels and structures. Summary of these research is presented in this paper, including mechanical properties of high strength steels at elevated temperature and after fire exposure, creep response of high strength steels at elevated temperature, residual stresses of welded high strength steel member after fire exposure, fire resistance of high strength steel columns, fire resistance of high strength steel beams, local buckling of high strength steel members, and residual strength of high strength steel columns after fire exposure. The results show that the mechanical properties of high strength steel in fire condition and the corresponding fire resistance of high strength steel structures are different from those of mild steel and structures, and the fire design methods recommended in current design codes are not applicable to high strength steel structures.

• ALGAE
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• v.35 no.4
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• pp.375-388
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• 2020

Ocean acidification and warming, identified as environmental concerns likely to be affected by climate change, are crucial determinants of algal growth. The ichthyotoxic raphidophytes Chattonella species are responsible for huge economic losses and environmental impact worldwide. In this study, we investigated the impact of CO2 on the thermal performance curves (TPCs) of Chattonella marina and Chattonella ovata grown under temperatures ranging from 13 to 34℃ under ambient pCO2 (350 μatm) and elevated pCO2 (950 μatm). TPCs were comparable between the species or even between pCO2 levels. With the exception of the critical thermal minimum (CTmin) for C. ovata, CTmin for C. marina and the thermal optimum (Topt) and critical thermal maximum (CTmax) for both species did not change with elevation of pCO2 levels. While CO2 enrichment increased the maximum photosynthetic rates (Pmax) up to 125% at the Totp of 30℃, specific growth rates were not significantly different under elevated pCO2 for the two species. Overall, C. ovata is likely to benefit from climate change, potentially widening its range of thermal tolerance limit in highly acidic waters and contributing to prolonged phenology of future phytoplankton assemblages in coastal waters.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.289-293
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• 2007

The effect of temperature on the forming limit diagram was investigated for AZ31B magnesium alloy sheet through the limit dome height test in the range from room temperature to $300^{\circ}C$. The formability of AZ31B sheet was improved significantly according to the increasing temperature. Also we studied the springback characteristics through the 2D draw bending test with different blank holding forces at elevated temperatures. Springback quantity was considerably reduced as temperature went up. The blank holding force in the range used, however, had little influence on springback. Experimental results obtained in this study may provide a material database for AZ31B sheet.

• Journal of Korea Foundry Society
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• v.11 no.4
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• pp.323-330
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• 1991

The relationships between the microstructure changes, retained austenite volume and elevated temperature tensile properties of Mo-Ni-Cu ADI corresponding to various austempering temperatures and time were investigated, After the $250^{\circ}C$ tensile test for the test piece austempered at $270^{\circ}C$ the accicular bainite structure was observed blunted under room temperature microscope. In the case of $370^{\circ}C$ austempering, the feathery bainite lath spacing was observed broadened. But after the $450^{\circ}C$ tensile test, bainitic features could not be observed. As the testing temperature increased, retained austenite volume tested at room temperature decreased. Especially, after the $450^{\circ}C$ tensile test retained austenite volume approached nearly to zero. A little higher tensile properties appeared at $250^{\circ}C$ testing than those at room temperature.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.52-55
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• 2000

The temperature effects of programming speed and endurance characteristics in p-channel flash memory cell have been investigated. In the case of room temperature, the programming speed of p-channel flash memory by using BTB scheme is faster than that by using CHE scheme. However, endurance characteristics with BTB programming scheme is not better than that with CHE programming scheme. In the case of elevated temperature, CHE programming speed is reduced due the gate current degradation but BTB programming speed is enhanced due to the increasing of gate current. Finally, the endurance characteristics of both schemes are improved due to the reduction of gate oxide traps.