• Korean Journal of Materials Research
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• v.16 no.9
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• pp.592-597
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• 2006

A deoxidized low-phosphorous (DLP) copper was processed by accumulative roll-bonding (ARB) for ultra grain refinement and high strengthening. Two copper sheets 1 mm thick, 30 mm wide and 300 mm long are first degreased and wire-brushed for sound bonding. The sheets are then stacked to each other, and roll-bonded by about 50% reduction rolling without lubrication at ambient temperature. The bonded sheet is then cut to the two pieces of same dimensions and the same procedure was repeated to the sheets up to eight cycles (${\varepsilon}{\sim}6.3$). TEM observation revealed that ultrafine grains were developed after the 4th cycle, and their size decreased at higher cycles. Tensile strength of the copper increased with the equivalent strain, and it reached 547 MPa which was 3 times higher than that of the initial material. It is concluded that the ARB process is an effective method for high strengthening of the DLP copper.

• Korean journal of applied entomology
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• v.61 no.2
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• pp.349-356
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• 2022

Fall armyworm, Spodoptera frugiperda, is a invasive migratory pest of native to the tropical and sub-tropical regions that has recently invaded Korea with damage to cornfield. The study was conducted to investigate the development periods of S. frugiperda on artificial diet at six different temperatures. The developmental period from eggs to adult at 18, 21, 24, 27, 30 and 32℃ was 79.8, 54.2, 34.3, 28.4, 24.6 and 24.0 days, respectivery and decreased with increasing temperature. The pupal periods of females were shorter than males. Most of the larvae developed through six instar, but the ratio of 7 or more instar increased at low temperatures. The relationship between the development rate and temperature was fitted with by linear regression analysis. The lower development threshold for egg and larva development was 12.9℃ and 11.3℃, respectively, 12.6℃ for pupae and 11.8℃ for egg-to-adult development. The effective accumulative temperature for the development of the respective life cycle stages were 37.0 DD for eggs, 286.3 DD for larvae, 132.2 DD for pupae and 456.8 DD egg-to-adult development.

• Environmental Engineering Research
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• v.20 no.4
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• pp.397-402
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• 2015

SCR has been popularly approved as one of the most effective means for NOx emission control in heavy-duty and medium-duty vehicles currently. However, high urea dosing would lead to ammonia slip. And $NH_3$ sensor for vehicle emission applications has not been popularly used in real applications. This paper presents experimental studies on the diesel engine urea-SCR system by using a double NOx sensor system that is arranged in the downstream of the SCR catalyst based on ammonia cross-sensitivity. It was shown that the NOx conversion efficiency rised as $NH_3/NOx$ increases and the ammonia slip started from the $NH_3/NOx$ equal to 1.4. The increase of temperature caused high improvement of the SCR reaction rate while the space velocity had no obvious change. The ammonia slip was in advance as catalyst temperature or space velocity increase and the ammonia storage reduced as catalyst temperature or space velocity increase. The NOx real-time conversion efficiency rised as the ammonia accumulative storage increase and reached the maximum value gradually.

• Korean journal of applied entomology
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• v.43 no.4 s.137
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• pp.305-310
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• 2004

The development of Myzus persicae (Sulzer) was studied at temperatures ranging from 15 to $32.5^{\circ}C$ under $70{\pm}5\%$ RH, and a photoperiod of 16:8 (L:D). Mortality of 1st-2nd nymph was higher than that of 3rd-4th nymph at the most temperature ranges whereas at high temperature of $32.5^{\circ}C$, more 3-4nymph stage individuals died. The total developmental time ranged from 12.4 days at $15^{\circ}C$ to 4.9 days at $27.5^{\circ}C$, suggesting that higher the temperature, faster the development. However, at higher end temperature ranges of 30 and $32.5^{\circ}C$, the development took 5.0 and 6.3 days, respectively. The lower developmental threshold temperature and effective accumulative temperatures for the total immature stage were $4.9^{\circ}C$ and 116.5 day-degrees. The nonlinear shape of temperature related development was well described by the modified Sharpe and DeMichele model. When the normalized cumulative frequency distributions of developmental times for each life stage were fitted to the three-parameter Weibull function, attendance of shortened developmental times was apparent with pre-nymph, post-nymph, and total nymph stages in descending order. The coefficient of determination $r^2$ ranged between 0.87 and 0.94.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.555-561
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• 1999

The development of sycamore lace bug, Corythucha ciliata, had been studied at four constant temperature levels of 15, 20, 25, and $30^{\circ}C$. And characteristics of its oviposition were studied at field. Developmental periods of eggs were 39.1, 17.1, 9.8, and 8.0 days, those of nymphs were 58.5, 23.8, 14.5, and 10.8 days, hatchabilities of eggs were 42.0, 78.5, 83.3, and 78.7%, and survival rates of nymphs were 14.7. 60.5, 75.7, and 48.9% at different temperatures of 15, 20, 25, and $30^{\circ}C$. Lower development threshold temperature and the effective accumulative temperature above the threshold required to complete development from egg to nymph were $11.5^{\circ}C$ and 344.8 degree days, respectively. The optimum temperature was estimated to be $25^{\circ}C$ for developments of egg and nymph. The longevities of adults were 41.0 days and 37.0 days for female and male, respectively.

• Korean journal of applied entomology
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• v.52 no.1
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• pp.5-12
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• 2013

The Hawaiian beet webworm (Spoladea recurvalis) is one of the serious insect pests found on red beet (Beta vulgaris var. conditiva) in Korea. The study was conducted to investigate the development period of S. recurvalis at various constant temperatures, 15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, 32.5 and $35.0^{\circ}C$, with $65{\pm}5%$ RH and a photoperiod of 16L:8D. The developmental period from egg to pre-adult was 51.0 days at $17.5^{\circ}C$ and 14.6 days at $35.0^{\circ}C$. The developmental period of S. recurvalis was decreased with increasing temperature. The relationship between the developmental rate and temperature was fitted well by linear regression analysis ($R^2{\geq}0.87$). The lower developmental threshold and effective accumulative temperature of the total immature stage were $10.4^{\circ}C$ and 384.7 degree days, respectively. The nonlinear relationship between the temperature and developmental rate was well described by the Lactin model. The relationship between the cumulative frequency and normalized distributions of the developmental period for each life stage were fitted to the Weibull function with $R^2=0.63{\sim}0.87$.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.387-394
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• 2013

The developmental times of mealworm beetle larvae, Tenebrio molitor were studied at six temperatures ranging from 15 to $30^{\circ}C$ with 60~70% RH, and a photoperiod of 14L:10D. Mortality of larval period was very low at 17 and $20^{\circ}C$ but did not die over $22^{\circ}C$. Developmental time of larva was decreased with increasing temperature. The total developmental time of T. molitor larvae was longest at $17^{\circ}C$ (244.3 days) and shortest at $30^{\circ}C$ (110.8 days). Egg and larvae were not developed at $15^{\circ}C$. The lower developmental threshold and effective accumulative temperatures for the total larval stages were $6.0^{\circ}C$ and 2564.1 degree-days, respectively. The relationship between developmental rate and temperature was fitted by a linear model and nonlinear model of Logan-6($r^2$=0.95). The distribution of completion of each development stage was well described by the 2-parameter Weibull function ($r^2$=0.8502~0.9390).

• Korean journal of applied entomology
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• v.35 no.4
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• pp.302-308
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• 1996

This study was conducted to investigate occurrence and host ranges of Liriomyza trifolii Burgess, American serpentineleafminer, in Chonnam province. Also, temperature effects on the development along with morphologicalcharacteristics in each instar of L. trifolii were studied. L. hifolii was observed from 22 species inthe 7 families. Gerbera, chrysanthemum and tomato were the most damaged host plants. Egg was transparentwhite with lengthlwidth of 0.27 mm10.25 mm while matured larva was yellow with that of 2.03 mm10.80 mmrevealing serpentine gallary under leaf cuticle. Pupa was light brown with that of 1.75 mrn10.74 mm and pupatedon the soil and/or leaf surface. Lengthlwing span of adult was 1.78 mm/3.43 mm. Number of oviposition/sucking punches by L. bifolii adult was 26.1% and 13.3% in tomato and gerbera leaves respectively. Feedingactivity of larval stage was highest at 2OoC. Developmental~threshold (DT) and effective accumulative temperatures(ET) on gerbera leaves were 11.2"C, 33.9DD in egg, 10.3'C, 38.6DD in larva, 10.7"C, 152.3DD inpupa, and 10.8"C, 222.8DD from egg to pupa. On tomato leaves, DT and ET were 13.6"C, 20.2DD in egg, 9.3"C, 43.7DD in larva, ll.O$^{\circ}$C, 114.3DD in pupa, and 11.6"C 178.2DD from egg to pupaDD in pupa, and 11.6"C 178.2DD from egg to pupa pupa.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.461-467
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• 2012

Developmental characteristics of Geocoris pallidipennis were investigated at a constant temperature ($20{\pm}1$, $25{\pm}1$, $30{\pm}1$, $35{\pm}1$, $37.5{\pm}1$ and $40{\pm}1^{\circ}C$), under long day illumination 16:8 (L:D) and constant relative humidity ($80{\pm}10%$). From egg to adulthood, the lower developmental threshold and the effective accumulative temperature were $14.8^{\circ}C$ and 399.1 day-degree, respectively. The experimental results at $35^{\circ}C$ were as follows. The egg period was 5.6 days (hatchability: 81.1%) and the nymphal period was 14.3 days (1st: 3.2, 2nd: 2.2, 3rd: 2.7, 4th: 2.7, 5th: 3.6). Female longevity was 33.8 days and the oviposition period was 29.2 days. Total egg production was 111.2 eggs and the maximum daily egg production was 14.8 eggs (in 7th days). However, although some eggs and nymphs developed at $37.5^{\circ}C$, G. pallidipennis could not develop at $40^{\circ}C$, The total egg production at $40^{\circ}C$ was only 22.1 eggs. When G. pallidipennis was fed on Bemisia tabaci pupae, daily prey consumption by nymphs (1st, 3rd and 5th) and adults was 1.9, 7.3, 18.7 and 29.5, respectively.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.283-289
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• 2013

This study was performed to investigate the biological characteristics of the brown lacewing Micromus angulatus (Stephens) at four different temperatures (15, 20, 25, and $30^{\circ}C$) and $70{\pm}10%$ relative humidity under a photoperiodic regime of 16:8(L:D) h. The developmental threshold and effective accumulative temperature from egg to pupa for M. angulatus were $9.6^{\circ}C$ and 270.3 day-degrees, respectively. The developmental period of egg, larva, and pupa at $25^{\circ}C$ was 4.4, 5.5, and 6.9 days. respectively. The longevity of an adult female M. angulatus was 34.9 days. The oviposition period for M. angulatus was 28.7 days, in which it laid a total number of 515.2 eggs during its life span. The maximum number of eggs laid by a female in a day was 54.8. Daily consumption by M. angulatus at $25^{\circ}C$ was 18.9 $1^{st}$ instars, 47.2 $2^{nd}$ instars, 57.7 $3^{rd}$ instars, and 91.0 adults of the glasshouse potato aphid, Aulacorthum solani. Therefore, M. angulatus could be a promising biological control agent against aphids.