• Journal of Environmental Science International
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• v.30 no.7
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• pp.585-595
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• 2021

We used seawater temperature data, measured in the Garolim Bay, to analyze temperature variation on an hourly and daily basis. Lagrange's interpolation using before and after data was applied to restore nonconsecutive missing temperature data. The estimated error of the data restoration was 0.11℃. Spectral analyses of seawater temperature showed significant periodicities of approximately 12.4 h (semidiurnal tide) and 15.0 d (long-period tide), which is close to those of M₂ and M_f partial tides. Variation in seawater temperature was correlated more with tidal height than with air temperature around the Garolim Bay. In June and December, when the seawater temperature difference between the inside and outside of the Garolim Bay was very large, the periodicities of 12.4 h and 15.0 d were highly prominent. These results indicate that the exchange of seawater between the inside and outside of the Garolim Bay induced variations in seawater temperature owing to tide. Understanding temperature variation because of tide helps to prevent abnormal mortality of cultured fish and to predict seawater temperature in the Garolim Bay.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.77-77
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• 2017

The sensitivities to photoperiod and temperature give guidance to choose an adaptable genotype for specific area in soybean production. However, there is insufficient information about the variation of sensitivities to photoperiod and temperature with wide genetic background. We investigated the sensitivities to photoperiod and temperature using 82 soybean mini core collection lines provided by NIAS gene bank of Japan. The seeds were sown on 28 May and 4 August in 2015, 24 May and 5 August in 2016 at field in Saga, Japan ($33^{\circ}$ 14' 32'' N, $130^{\circ}$ 17' 28'' E) for the early (average photoperiod and temperature: 15.2 h and $25.1^{\circ}C$) and late (13.6 h and $27.2^{\circ}C$) sowing respectively. The plants were also grown in the growth chamber under 12 h photoperiod with three temperature regimes (day/night temperature: $25/18^{\circ}C$, $28/22^{\circ}C$ and $33/28^{\circ}C$). Emergence date, days to first flower were recorded with 10 plants in the field and 2 plants in the growth chamber for each line. The data for daily average temperatures and photoperiodic hours were collected from weather station. The days from emergence to first flower open (DEF) were varied from 23-92 (2015 and 2016) in early sowing whereas 18-68 (2015) and 18-59 (2016) in late sowing. The shortened DEF in late sowing could be caused by both short photoperiod and high temperature in late sowing. However, the accumulated temperatures during emergence to first flower open (ATEF) were less variable in comparison with DEF, suggesting the ATEF is dependent mostly on the photoperiod. The ATEF were found same between early and late sowing in some early flowering lines (e.g. $686.7^{\circ}C$ and $687.6^{\circ}C$ in HEUKDAELIPS, $728.8^{\circ}C$ and $706.3^{\circ}C$ in WILLIAMS'82) which indicated that these would be insensitive to day length. In the growth chamber experiment, the variation in both DEF and ATEF was a little greater at low temperature ($25/18^{\circ}C$) but almost same at middle ($28/22^{\circ}C$) and high ($33/28^{\circ}C$) temperatures. Since the less differences in ATEF were found between the three temperatures, it is suggested that the temperature plays only a quantitative effect on the flower initiation, and the large ATEF in some lines may indicate the stronger photosensitivity even at 12 h or longer juvenile phase. Some lines with the lowest ATEF regardless of growth conditions, such as FISKEBY V, KE 32 (ATEF: 559.6-666.5, 587.7-709.5) might lack the sensitivities to both photoperiod and temperature. The results suggested that soybean genotypes has wider variation in sensitivity to photoperiod, whereas less variation to temperature.

• Journal of Environmental Science International
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• v.9 no.4
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• pp.303-309
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• 2000

The relationship between air temperature and sea surface temperature and studied using the daily air temperature and sea surface temperature data for 25 years (1970~1994) at 9 coastal stations in Korea. Seasonal variations of air temperature have larger amplitudes than those of sea surface temperature. The seasonal variations of air temperature leads those of sea surface temperature by 2 to 3 weeks. The anomalies of sea surface temperature and air temperature with time scales more than 1 month are more ghighly correlated than those of short term, with time scales less than 1 month. Accumulated monthly anomalies of sea surface temperature and air temperature for 6 months shwoed higher correlation than the anomailes of each month. The magnitudes of sea surface temperature and air temperature anomalies are related with the duration of anomalies. Their magnitudes are large when the durations of anomalies are long.

• Tunnel and Underground Space
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• v.6 no.2
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• pp.101-121
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• 1996

The thermomechanical characteristics of rocks such as temperature dependency of strength and deformation were experimentally investigated using Iksan granite, Cheonan tonalite and Chung-ju dolomite for proper design and stability analysis of underground structures subjected to temperature changes. For the temperature below critical threshold temperature $T_c$, the variation of uniaxial compressive strength, Young's modulus, Brazilian tensile strength and cohesion with temperature were slightly different for each rock type, but these mechanical properties decreased at the temperatures above $T_c$ by the effect of thermal cracking. Tensile strength was most affected by $T_c$, and uniaxial compressive strength was least affected by $T_c$. To the temperature of 20$0^{\circ}C$ with the confining prressure to 150 kg/$\textrm{cm}^2$, failure limit on principal stress plane and failure envelope on $\sigma$-$\tau$ plane of Iksan granite were continuously lowered with increasing temperature but those of Cheonan tonalite and Chung-ju dolomite showed different characteristics depending on minor principal stress on principal stress plane and normal stress on $\sigma$-$\tau$ plane. The reason for this appeared to be the effect of rock characteristics and confining pressure. Young's modulus was also temperature and pressure dependent, but the variation of Young's modulus was about 10%, which was small compared to the variation of compressive strength. In general, Young's modulus increased with increasing confining pressure and increased or decreased with increasing temperature to 20$0^{\circ}C$ depending on the rock type.

• 한국해양학회지
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• v.17 no.2
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• pp.74-82
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• 1982

The study on the variation coefficient of water temperature and salinity was comducted during the year from 1968 to 1980 in the Southern Sea of Korea. The results obtaland from the study as followes; 1. The variation coefficient of water temperature and salinity wewe large either at the front area or the thermocline and malocline area. 2. The variation coefficient of water temperature was the largest at the time when the power was strong ty each water mass(The largest value in Tsushima and Yellow Sea Warm Current area was occurred at the 50m layer in the Summer, and that in the South Korean Coastal Water area and the Southern Part of Yellow Sea was at all layer in the Winter). 3. The variation coefficient of salinity was the largest at the surface layer in warm current area that was influenced by the low salinity of the East China Coastal Water in the Summer ,and that of salinity in the South Korean Coastal Water area and Soutern Part of Yellow Sea was nearly half of the value of the warm current area.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.264-273
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• 2001

The conjugate heat transfer from a protruding module in a horizontal channel with a variation of air temperature is experimentally investigated. It is an aim of this study is to estimate temperature difference between a module and air. This study is performed with a variation of parameters that are air temperatures($T_i,=25^{\circ}C{\sim}55^{\circ}C),$ thermal resistance($R_c=158 K/W),$ air velocities ( 4V_i=0.1$ m/s~l.5 m/s ), and input power (Q=3 W, 7 W ). The results show that as the thermal resistance increases, the effect of air temperatures are decreased. And input power was most effective parameter on the temperature difference between a module and air.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.9
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• pp.686-691
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• 2012

In this paper, we designed a Chua's chaotic circuit using transcondcutor based nonlinear resistor. Proposed chaotic circuit consist of L, C, R and transcondcutor based Chua's diode. We performed SPICE simulation for chaotic dynamics such as time seriesform, frequency analysis and phase plane of the circuit. Chaotic dynamics of the circuit was analysed according to MOS size variation of the operational transconductance amplifier. Also, we performed SPICE circuit analysis for temperature dependance of the circuit. SPICE results showed that chaotic dynamics of the circuit varied according to the temperature variation and chaotic signals were generated in specific temperature conditions.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.10
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• pp.805-812
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• 2003

This paper presents a method to investigate the characteristics of a ball bearing and the dynamics of a HDD spindle system due to temperature variation. Finite element model is developed for the rotating and stationary parts of a HDD spindle system separately to determine their thermal deformations by using ANSYS, a finite element program. Then, the relative position of the rotating part with respect to the stationary part is determined by solving the equilibrium equation of the contact force between upper and lower ball bearings. The validity of the proposed method is verified by comparing the theoretical natural frequencies of a HDD spindle system with the experimental ones before and after temperature variation. It shows that the elevated temperature results in the increase of contact angle and the decrease of bearing deformation, contact force and bearing stiffness, which result in the decrease of the natural frequencies of a HDD spindle system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.319-324
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• 2011

This study aims to investigate statistical variations and relationships of blood pressure (BP), phtotplethysmography (PPG) and cardiovascular parameters on changes in local skin surface temperature (SST) during gradual cooling and heating. Results showed that local SST changes affected the Finometer BP, the PPG waveforms and total peripheral resistance, but not oscillometric BP, heart rate, stroke volume and cardiac output. Therefore, in order to reduce for the errors, temperatures should be controlled or compensated when components of the PPG waveform are used to evaluate cardiovascular status in temperature variation environments.

• Atmosphere
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• v.18 no.4
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• pp.429-439
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• 2008

The lower-stratospheric polar temperature in winter and spring for both hemispheres is investigated based on the NCEP/NCAR 50-year reanalysis data with respect to the strength of the stratospheric eddy heat flux. Both the polar temperature and the eddy heat flux show significant variation on the decadal and year-to-year time scales except during the Southern Hemisphere winter. The year-to-year variation in the polar temperature is mainly determined by the eddy heat flux convergence. The eddy heat flux convergence is compared with the diabatic heating rate obtained from a two-dimensional model. Radiative heating caused by absorption of solar radiation is comparable to the heating caused by the eddy heat flux convergence in the Southern Hemisphere. The effect of ozone depletion on diabatic heating has been found to be secondary in the Northern Hemisphere, even in March 1997 when the record depletion of ozone took place.