• Journal of the Microelectronics and Packaging Society
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• v.12 no.2 s.35
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• pp.135-140
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• 2005

Although it was recently observed that severe fatigue damage was formed in Al or Cu interconnects due to the cyclic temperatures generated by Joule heating of the metal lines by the passage of alternating currents (AC), AC loading frequency effect on the damage evolution characteristics are not known so far. This work focused on the effect of AC loading frequency (100 Hz vs. 10 kHz) on the thermo-mechanical fatigue characteristics by using polycrystalline sputtered Cu lines with temperature cycles with amplitudes from 100 to $300^{\circ}C$. It was consistently observed that higher loading frequency accelerated damaged grain growth and led to earlier failure irrespective of Cu grain sizes. The frequency effect is believed to result from differences in the concentration of defects created by the deformation-induced motion of dislocations to the grain boundaries.

• Korean Journal of Plant Resources
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• v.13 no.3
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• pp.202-207
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• 2000

This study was conducted to investigate the characteristics of seed germination pattern by the prechilling and alternating temperature treatments to 16 species of native plant. The seed length, width and thickness ranged from 1.1 to 8.9 mm, from 0.7 to 7.5 mm and from 0.4 to 1.7 mm, respectively. In addition, the 1,000 grain weight of native plants ranged from 0.1 to 8.8g. Germination rate of Melandryum firmum R. and Saussurea pulchella F. with light condition, Capsella bursa-pastoris L. and Leonurus sibiricus L. with dark conditionin of non-treatment were the highest 69, 81,16 and 36%, respectively. Germination rate of Aster scaber T., Cirsium setidens N., Ligularia fischeri T., Plantago asiatica L., and Saussurea sp. of 5$^{\circ}C$ prechilling for 30 days were the highest 84, 29, 29, 57, 78 and 95% with light condition respectively, 30% but Cirsium nipponicum M. only with dark condition. Germination rate of Aralia elata S., Aster koraiensis N. and Synurus deltoides N. of alternating temperature with 8 hours at 3$0^{\circ}C$ and 16 hours at 15$^{\circ}C$ were the highest 2 and 57% with light condition and 52% with dark condition.

• Korean journal of applied entomology
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• v.26 no.1 s.70
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• pp.13-23
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• 1987

This study was conducted to know the effects of temperature conditions on the growth and oviposition of the brown planthopper(BPH), Nilaparvata lugens $St{\aa}l$. Results obtained were to predict the timing of the BPH control by measuring population dynamics of the BPH in response to temperature fluctuations upon migration of the insects in paddy fields. Developmental and ovipositional rates under constant and alternating temperature conditions were observed in a plant growth cabinet. Hatchabilities of eggs of the BPH were the highest at $25^{\circ}C$ and were decreased below or above the optimum temperature. Egg periods were the shortest at $27.5^{\circ}C$ and prolonged with decreasing temperature, but retarded at higher temperature above $30^{\circ}C$. Adult emergence rates were the highest at $27.5^{\circ}C$ and reduced with decreasing temperature, and no adult emerged at $32.5^{\circ}C$ and $35^{\circ}C$. Developmental period of nymph was the shortest at both $27.5^{\circ}C$ and $30^{\circ}C$, but extended with decreasing temperature. Female longevity was increased with decreasing temperature and the male longevity was the shortest at $27.5^{\circ}C$. Preoviposition period was the shortest at $32.5^{\circ}C$, but prolonged with decreasing temperature. It was about 6.5 times longer at $17.5^{\circ}C$ than that at $32.5^{\circ}C$. Number of eggs oviposited per female was the greatest at $25^{\circ}C$, but decreased at the temperature below or above the optimum. Under the same total effective day-degrees, hatchabilty at the alternating temperature was about 10% higher than that at the constant temperature but egg period at the alternating temperature was nearly identical as that at the constant. Under the $22^{\circ}C$ condition, emergence rate was about 8% higher at the alternating temperature than that at the constant, however, at the $28^{\circ}C$, the rate was about 8% higher at the constant than that at the alternating. Nymphal period was about $4{\sim}6$ days longer at the alternating temperature than that at the constant. Under the same total effective day-degrees in adult stage, both longevity and oviposition period were longer at alternating temperature than those at the constant. Number of eggs oviposited per female was also higher at the alternating. Longevities of females reared under $28^{\circ}C$ of constant temperature was the longest no matter what temperatures they were exposed after the emergence. This result seems to be indicating that female longevity is greatly influenced by the temperature to which they were exposed durings immature stages. Preoviposition period was affected by the temperature exposed during the nympal and adult stage whereas the number of eggs oviposited was affected by the temperature during the adult stage only. Based on the results from this study, the developmental threshold temperatures seem to be $14.12^{\circ}C$ for eggs, $14.76^{\circ}C$ for nymphs, $9.62^{\circ}C$ for adults, and $15.95^{\circ}C$ for preoviposition period. Estimated values of the total effective temperature for completing each stage were 141.25 day-degrees for eggs, 167.83 day-degrees for nymphs, 349.64 day-degrees for adults, and 58.60 day-degrees for preoviposition.

• The Korean Journal of Ecology
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• v.12 no.4
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• pp.219-236
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• 1989

The effect of salinity on the seed germination and seedling growth of Pinus densiflora for. erecta Uyeki were studied under the controlled conditions in the growth chamber. The seeds were sorted into three classes in weight such as large ($15.49\pm$1.63mg), medium($10.61\pm$1.38mg), and small ($6.57\pm$1.33mg) to determine the role of seed weight in germination and seedling growth of the pine. Polymorphic seeds of the pine were germinated an salinity range of 0 to 1.5% NaCl under various temperature ($10^{\circ}$ $-25^{\circ}$ with $5^{\circ}$C interval of constant temperature, and $10^{\circ}$ $-20^{\circ}$C, $15^{\circ}$ $-25^{\circ}$C of alternating temperature) in order to determine their germinability and seeding growth. In control plot, there was little difference of germination percentage among the seed weight classes, but in saline plot, the larger seeds generally had a higher percentage and rate of germination. There occurred synergistic interaction between salinity and temperature in the germination and the increase of temperature enhanced germination of seeds at the same salinity level. Alternating temperature regimes of $15^{\circ}$-$25^{\circ}$C yielded maximum germination and no germination was occurred at $10^{\circ}C$. The germination at alternating temperature showed higher germination percentage than at constant temperature. The percentage and of germination decreased drastically with increased salinity level to 1.00%; no germination was occurred at 1.50% salinity level. The growth fo sddelings from larger seeds was better than that of smaller seeds at the same salinity and temperature. The hypocotyl and radicle were more sensitive than cotyledon to the increased salinity stress.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.44-44
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• 2019

Spring sowing of ginseng seeds often results in failure of seedling establishment. Storage condition during winter, sowing time, and seed treatment might effect on germination. Here we tested effects of temperature regimes of seed storage on spring sowing. Dehisced wet or dry ginseng seeds were stored at $2^{\circ}C$, $-2^{\circ}C$, $-3.5^{\circ}C$, or alternating temperature: at $2^{\circ}C$ until December, $-3.5^{\circ}C$ in January, and $2^{\circ}C$ in February, and sowed in March. In overall, emergence rate was dependent on storage temperature, and $-3.5^{\circ}C$ resulted poorest emergence than other conditions. Storage of wet seeds in alternating temperature resulted highest emergence rate. Seed dry also affected on emergence rate, while it was dependent on the storage temperature. In terms of growth, storage at $2^{\circ}C$ as wet seed resulted highest growth, and dried seeds resulted poorer growth than wet seeds. As a modification of alternating temperature, seeds were stored at $2^{\circ}C$ at first, then transferred to $-3.5^{\circ}C$ at Nov 30, Dec 20, and Jan 10, each. When transfer date was delayed, emergence rate was increased. We suggest that seed storage temperature for ginseng should not be decreased below $-2^{\circ}C$, and alternative temperature regime for successful spring sowing could be useful.

• Journal of Magnetics
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• v.17 no.1
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• pp.42-45
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• 2012

We have developed an alternating magnetic field stimulation system consisting of a switched-mode power supply and a digital control circuit which modulates a duty ratio to maintain a magnetic field intensity of a few mT even while the frequency increases up to 4 kHz with a controllable coil temperature below $30^{\circ}C$ in air. This duty ratio modulation and water circulation are advantageous for cell culture under ac-magnetic field stimulation by preventing the incubator from exceeding a cell-viable temperature of $37^{\circ}C$. Although the temperature of the coil when subjected to a sinusoidal voltage rapidly increased, that of our system modulated by the duty factor did not change. This is a potentially valuable method to investigate the effects of intermediate frequency magnetic field stimulation on biological entities such as cells, tissues and organs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.11
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• pp.1041-1046
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• 2003

In order to improve the surface uniformity and the conduction properties of the fabricated YBCO thick films, a system that applies alternating field vertically to the EPD field has been developed for the first time and applied to the electrophoretic deposition process. The applied alternating electric field, so called Shaky Alternating Assisted Field, caused a force to be exerted on each YBCO particle and resulted in a shaking of the particle in the direction of applied electric field, accomplishing a uniform particle orientation. The usual commercial electrical power was used for the vertically applied alternating voltage and the induced electric field was 25-120 V/cm at 60Hz. The thick film fabricated by the method developed in this paper showed better surface uniformity without crack and porosity and improved film characteristics such as critical temperature (Tc,zero = 90 K) and critical current density (2354 A/$\textrm{cm}^2$), Therefore, it is expected that the shaky-aligned electrophoretic deposition method can be used to fabricate superconductor films through a simpler process and at less expense.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1709-1714
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• 2004

The changes of microflora and enzyme activities in Alaska pollack sikhae were evaluated in 3 different temperature conditions, 5$^{\circ}C$, 2$0^{\circ}C$ and alternating temperature (stored at 5$^{\circ}C$ after 10 days of fermentation at 2$0^{\circ}C$), respectively. The number of proteolytic bacteria and 2 lactic acid bacteria including Lactobacillus sp. and Pediococcus sp. increased rapidly up to 10 days and composed major portion of total viable cell (TVC) in sikhae fermented at 2$0^{\circ}C$, whereas those of TVC were occupied by Lactobacillus sp., Pediococcus sp. and yeast after 10 days of fermentation. The major species of microflora in sikhae fermented at alternating temperature were, composed of Lactobacillus, Pediococcus and Streptococcus after 10 days of fermentation. Especially, Leuconostoc sp. was kept up to 27 days at 5$^{\circ}C$ than other temperature conditions (16 days). The activities of protease and lipase in acidic region (pH 3.0) were higher at 2$0^{\circ}C$ than at 5$^{\circ}C$ due to sensitivity of temperature, although those of protease and lipase in neutral region (pH 7.0) were not found any differences in both temperatures. Changing temperature condition from 2$0^{\circ}C$ to 5$^{\circ}C$ in alternating temperature inactivated protease activity, whereas lipase activity was still maintained during fermentation.

• Journal of the Korean Wood Science and Technology
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• v.41 no.5
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• pp.456-465
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• 2013

Log cross sections of yellow poplar were dried in a radio frequency vacuum (RFV) dryer under alternating vacuum and release (AVR) process. The average moisture content (MC), temperature and vapor pressure at the volumetric center were monitored as functions of time. Three different log thicknesses (33, 60 and 75mm) were tested. The results show that the AVR process caused an increase in the drying rate when the moisture content was above fiber saturation point (FSP, about 30% MC) but that it had an inverse effect on the drying rate when the MC was below FSP. The effect of the AVR process on the drying rate decreased, and the severity of heart checks increased, with the increase in the thickness of the specimens.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.2
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• pp.121-128
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• 2022

The aims of this study were to optimize the processing procedure of high-quality semi-alternating temperature dried Israeli carp Cyprinus carpio (SAD-IC) and to investigate the sensory properties of the product. Based on the differences in moisture content of the dorsal and ventral muscles, high quality SAD-IC was prepared by alternating the drying temperature between 4 h at 35℃, and 2 h at 5℃, three times before final drying for 2 h at 35℃. The surface in SAD-IC produced under the optimal alternating-temperature drying process had a markedly superior browning index value and softer texture compared to products produced using constant-temperature drying. SAD-IC produced from dorsal and ventral muscle had significantly superior taste values than the raw material. These results suggest that SAD-IC has the potential to be industrialized.