• Geomechanics and Engineering
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• v.16 no.1
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• pp.49-58
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• 2018

Open-mode cracks could be commonly observed in layered rocks. A concept model is firstly used to explore the mechanism of the vertical cracks (VCs) in the top layer. Then the crack behaviour of the two-layer model is simulated based on a cohesive zone model (CZM) for layer interfaces and a plastic-damage model for rocks. The model indicates that the tensile stress normal to the VCs changes to compression if the crack spacing to layer thickness ratio is lower than a threshold. The results indicate that there is a threshold for interfacial shear strength that controls the crack patterns of the layered system. If the shear strength is lower than the threshold, the top layer is meshed by the VCs and interfacial cracks (ICs). When the shear strength is higher than the threshold, the top layer is meshed by the VCs and parallel cracks (PCs). If the shear strength is comparative to the threshold, a combining pattern of VCs, PCs and ICs for the top layer can be formed. The evolutions of stress distribution in the crack-bound block indicate that the ICs and PCs can reduce the load transferred for the substrate layer, and thus leads to a crack saturation state.

• The Korean Journal of Soil Zoology
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• v.5 no.2
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• pp.119-123
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• 2000

Effect of fluctuating temperatures on the development of the immature beet armyworm, Spodoptera exigua (H bner), was analyzed. At constant rearing temperature regimes, the estimated developmental threshold temperatures were varied among stages and instars, but had an average 13$^{\circ}C$ from egg hatch to adult emergence. Based on the 13$^{\circ}C$ threshold temperature, we set up three different rearing temperature regimes having the same day-degrees. Two fluctuating temperature regimes changed significantly the developmenta1 period expected by the constant rearing temperature regime. Under the same thermophase temperature (25$^{\circ}C$), the thermocycling regime with the higher cryophase temperature (10$^{\circ}C$) decelerated the developmental rate probably by lowering temperature limit thor development, but that with the lower cryophase temperature (5$^{\circ}C$) gave a negative developmental effect.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.35-39
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• 2015

The developmental responses of insects to temperature are important considerations in gaining a better understanding of their ecology and life histories. Temperature-dependent phenology models permit examination of the effects of temperature on the geographical distributions, population dynamics, and management of insects. Measurements of insect developmental and survival responses to temperature pose practical challenges that depend on the chosen modality, variability among individuals, and high mortality rates near the lower and upper threshold temperatures. Different temperature levels can significantly affect larval development of Eurema hecabe. The development of E. hecabe reared on leaves of Lespedeza cuneata was investigated at three temperature regimes (20, 25, and 30℃), a relative humidity of 60%, and a light:dark photoperiod of 14:10 h. The developmental time from larva to adult was 34.3, 20.6, and 17.9 d at temperatures of 20, 25, and 30℃, respectively. Pupal rate was 47.6%, 47.6%, and 61.9% at temperatures of 20, 25, and 30℃, respectively. The developmental threshold temperature estimated from larva to pupae was 8.1℃ with 381.7 degree-days. There is an increasing need for a standardized manual for rearing this butterfly species based on adequate knowledge of its ecology.

• Animal Bioscience
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• v.34 no.4
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• pp.714-723
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• 2021

Objective: This study aimed to determine the effects of soft pellet creep feed (SPCF) on growth performance and intestinal development in piglets. Methods: A total of 18 sows and their litters of crossbred piglets (14±2 days, 3.73±0.72 kg) were assigned to one of three dietary groups receiving i) powder creep feed (PCF), ii) hard pellet creep feed (HPCF) or iii) SPCF during the pre-weaning period. After weaning, piglets were selected for continuous evaluation of the three diets on growth performance and intestinal health. Results: In the pre-weaning period, the average daily feed intake and average daily dry matter intake were significantly higher in the SPCF group than the HPCF group (p<0.05). In the post-weaning and entire experimental period, the different diets had no significant effect on growth performance. At 10 d after weaning, the serum glucose concentration was lower in the SPCF group (p<0.05) than the other groups; a higher (p<0.05) villus height and lower (p<0.05) crypt depth in the jejunum were also observed in the SPCF group than the other groups; Meanwhile, in the duodenum and jejunum, the SPCF group had a higher (p<0.05) villus height to crypt depth ratio than the other groups; Furthermore, the higher (p<0.05) threshold cycle values of lactic acid bacteria and lower (p<0.05) threshold cycle values of Clostridium, Enterobacter and Escherichia coli were also observed in the SPCF group, and the sucrase and maltase activity was higher (p<0.05) in the SPCF group than the other groups in duodenum and ileum. Conclusion: The SPCF improved pre-weaning feed intake and decreased the negative effects of weaning stress in the intestine in piglets.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.12
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• pp.9-17
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• 2021

Globalization is an economic process responsible for the increase of interdependence of world economies. It enhances the mobility of national resources internationally via the integration of markets, trade and investments with minimal barriers to slow the flow of products and services. Although globalization has some positive impacts on the economy, it is said to be a factor in the decline of income inequality of the participating countries. However, the results of previous studies on the relationship between globalization and income inequality are inconclusive. This suggests that there are other factors influencing the relationship between the two variables. The purpose of this study is to examine the role of intelligence (IQ) in the globalization-income inequality relationship. This study employs the threshold regression technique and cross-nation observations from 117 sample nations for the period 1980-2016. The results show that the impact of globalization on income inequality in a nation relies on its IQ level. The results imply that economic globalization has a negative impact on income inequality in nations with lower IQ levels. It widens the gap between the poor and rich. While in nations with higher IQ levels, it seems to not have any significant impact on income distribution.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.196-202
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• 2004

The development of new materials with light weight and high strength has become vital to the machinery, aircraft and auto industries. However, there are a lot of problems with developing such materials that require expensive tools, and a great deal of time and effort. Therefore, the improvement of fatigue strength and fatigue life are mainly focused on adopting residual stress(in this thesis). The compressive residual stress was imposed on the surface according to each shot velocity(57, 70, 83, 96 m/sec) based on Shot-peening, which is the method of improving fatigue life and strength. By using the methods mentioned above, the following conclusions have been drawn. 1. The fatigue crack growth rate(da/dN) of the Shot-peened material was lower than that of the Un-peened material. And in stage I, ΔKth, the threshold stress intensity factor, of the shot-peen processed material is high in critical parts unlike the Un-peened material. Also m, fatigue crack growth exponent and number of cycle of the Shot-peened material was higher than that of the Un-peened material. That is concluded from effect of da/dN. 2. Fatigue life shows more improvement in the Shot-peened material than in the Un-peened material. And compressive residual stress of surface on the Shot-peen processed operate resistance force of fatigue crack propagation.

• Korean journal of applied entomology
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• v.61 no.4
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• pp.563-575
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• 2022

Maruca vitrata is one of important pests in leguminous crops, especially red bean. We investigated the effects of temperature on development of each life stage, adult longevity and fecundity of M. vitrata for understanding the biological characteristics of the insect species at eight constant temperatures of 13, 16, 19, 22, 25, 28, 31, and 34℃. Eggs hatched successfully at all temperature subjected and larvae successfully developed to the adult stage from 16℃ to 31℃. The developmental period of egg decreased up to 31℃ and after then increased. The developmental period of larva and pupa, and adult longevity of M. vitrata decreased with increasing temperature. Lower and higher threshold temperature (TL and TH) were calculated by the Lobry-Rosso-Flandrois (LRF) and Sharpe-Schoolfield-Ikemoto (SSI) models. The lower developmental threshold (LDT) and thermal constant (K) from egg hatching to adult emergence of M. vitrata were estimated by linear regression as 12.8℃ and 280.8DD, respectively. TL and TH from egg hatching to adult emergence using SSI model were 14.2℃ and 31.9℃. Thermal windows, i.e., the range in temperature between the minimum and maximum rate of development, of M. vitrata was 17.7℃. In addition, we constructed the oviposition models of adult, using the investigated adult traits including survival, longevity, oviposition period and fecundity. Temperature-dependent development models and adult oviposition models will be helpful to understand the population dynamics of M vitrata and to establish the strategy of integrated pest management in legume crops.

• Korean journal of applied entomology
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• v.61 no.4
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• pp.577-590
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• 2022

Ostrinia scapulalis is one of important pests in leguminous crops, especially red bean. In order to understand the biological characteristics of the insect, we investigated the effects of temperature on development of each life stage, adult longevity and fecundity of O. scapulalis at eleven constant temperatures of 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, and 36℃. Eggs and larvae successfully developed next life stage at most temperature subjected except 7, 10 and 13℃. The developmental period of egg, larva and pupa decreased as temperature increased. Lower and higher threshold temperature (TL and TH) were calculated by the Lobry-Rosso-Flandrois (LRF) and Sharpe-Schoolfield-Ikemoto (SSI) models. The lower developmental threshold (LDT) and thermal constant (K) from egg hatching to adult emergence of O. scapulalis were estimated by linear regression as 13.5℃ and 384.5DD, respectively. TL and TH from egg hatching to adult emergence using SSI model were 19.4℃ and 39.8℃. Thermal windows, i.e., the range in temperature between the minimum and maximum rate of development, of O. scapulalis was 20.4℃. Adults produced viable eggs at the temperature range between 16℃ and 34℃, and showed a maximum number, ca. 416 offsprings, at 25℃. Adult models including aging rate, age-specific survival rate, age-specific cumulative oviposition, and temperature-dependent fecundity were constructed, using the temperature-dependent adult traits. Temperature-dependent development models and adult oviposition models will be useful components to understand the population dynamics of O. scapulalis and will be expected using a basic data for establishing the strategy of integrated pest management in leguminous crops.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.435-447
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• 2022

The soybean podborer, Matsumuraeses falcana (Lepidoptera: Tortricidae), is one of important pests in soybean crop. In the purpose of forecasting population dynamics of M. falcana, we investigated the effects of temperature on development of each life stage, adult longevity and fecundity of Matsumuraeses falcana at seven constant temperatures of 10, 13, 19, 22, 25, 28, and 31℃. Eggs hatched successfully at all temperature subjected. M. falcana developed from egg hatching to adult emergence at the tested temperatures except 10, 13, and 31℃. The developmental period of each life stage and adult longevity of M. falcana decreased as temperature increased. The lower developmental threshold (LDT) and thermal constant (K) from egg hatching to adult emergence of M. falcana were estimated by linear regression as 10.2℃ and 492.04DD, respectively. Lower and higher threshold temperature (TL and TH) were calculated by the Lobry-Rosso-Flandrois (LRF) and Sharpe-Schoolfield-Ikemoto (SSI) models. TL and TH from egg hatching to adult emergence using SSI model were 16.7℃ and 29.1℃. Thermal windows, i.e., the range in temperature between the minimum and maximum rate of development, of M. falcana was 12.4℃. We constructed the adult oviposition model of M. falcana using adult survivorship and fecundity. Temperature-dependent immature development and adult oviposition models will help constructing the population model of M. falcana and developing the strategies of integrated pest management in soybean fields.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.461-473
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• 2022

Matsumuraeses phaseoli is one of important pests in soybean crops, especially adzuki beans. We investigated the effects of temperature on development of each life stage, adult longevity and fecundity of M. phaseoli for understanding the biological characteristics of M. phaseoli at ten constant temperatures of 7, 10, 13, 16, 19, 22, 25, 28, 31, and 34℃. Eggs hatched successfully at all temperature subjected except 7℃ and 34℃. The developmental period of each life stage and adult longevity of M. phaseoli decreased as temperature increased. Lower and higher threshold temperature (TL and TH) were calculated by the Lobry-Rosso-Flandrois (LRF) and Sharpe-Schoolfield-Ikemoto (SSI) models. The lower developmental threshold (LDT) and thermal constant (K) from egg hatching to adult emergence of M. phaseoli were estimated by linear regression as 9.04℃ and 422.97DD, respectively. TL and TH from egg hatching to adult emergence using SSI model were 20.0℃ and 32.3℃. Thermal windows, i.e., the range in temperature between the minimum and maximum rate of development, of M. phaseoli was 12.3℃. We constructed the adult oviposition model of M. phaseoli using adult survivorship and fecundity. Temperature-dependent development models and adult oviposition models will be helpful to understand the population dynamics of M. falcana and to establish the strategy of integrated pest management in soybean fields.