• Phonetics and Speech Sciences
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• v.7 no.2
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• pp.63-73
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• 2015

This study investigated longitudinally early vocalization and phonological developments of typically developing children. Ten typically developing children participated in the study from 9 months to 18 months of age. Spontaneous utterance samples were collected at 9, 12, 15, 18 months of age and phonetically transcribed and analyzed. Utterance samples were classified into 5 levels using Stark Assessment of Early Vocal Development-Revised(SAEVD-R). The data analysis focused on 4 and 5 levels of vocalizations classified by SAEVD-R and word productions. The percentage of each vocalization level, vocalization length, syllable structures, and consonant inventory were obtained. The results showed that the percentages of level 4 and 5 vocalizations and word significantly increased with age and the production of syllable structures containing consonants significantly increased around 12 and 15 months of age. On average, the children produced 4 types of syllable structure and 5.4 consonants at 9 months and they produced 5 types of syllable structure and 9.8 consonants at 18 months. The phonological development patterns in this study were consistent with those analyzed from children's meaningful utterances in previous studies. The results support the perspective on the continuity between babbling and early speech. This study has clinical implications in early identification and speech-language intervention for young children with speech delays or at risk.

• Journal of Korean Neurosurgical Society
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• v.55 no.3
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• pp.125-130
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• 2014

Objective : This study was conducted to elucidate neuroprotective effect of carnosine in early stage of stroke. Methods : Early stage of rodent stroke model and neuroblastoma chemical hypoxia model was established by middle cerebral artery occlusion and antimycin A. Neuroprotective effect of carnosine was investigated with 100, 250, and 500 mg of carnosine treatment. And antioxidant expression was analyzed by enzyme linked immunosorbent assay (ELISA) and western blot in brain and blood. Results : Intraperitoneal injection of 500 mg carnosine induced significant decrease of infarct volume and expansion of penumbra (p<0.05). The expression of superoxide dismutase (SOD) showed significant increase than in saline group in blood and brain (p<0.05). In the analysis of chemical hypoxia, carnosine induced increase of neuronal cell viability and decrease of reactive oxygen species (ROS) production. Conclusion : Carnosine has neuroprotective property which was related to antioxidant capacity in early stage of stroke. And, the oxidative stress should be considered one of major factor in early ischemic stroke.

• Advances in concrete construction
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• v.16 no.5
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• pp.255-267
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• 2023

The production of ultra-early-strength concrete (UESC) traditionally involves complexity or necessitates high-temperature curing conditions. However, this study aimed to achieve ultra-early-strength performance solely through room-temperature curing. Experimental results demonstrate that under room-temperature (28℃) curing conditions, the concrete attained compressive strengths of 20 MPa at 4 hours and 69.6 MPa at 24 hours. Additionally, it exhibited a flexural strength of 7.5 MPa after 24 hours. In contrast, conventional concrete typically reaches around 20.6 MPa (3,000 psi) after approximately 28 days, highlighting the rapid strength development of the UESC. This swift attainment of compressive strength represents a significant advancement for engineering purposes. Small amounts of steel fibers (0.5% and 1% by volume, respectively) were added to address potential concrete cracking due to early hydration heat and enhance mechanical properties. This allowed observation of the effects of different volume contents on ultra-early-strength fiber-reinforced concrete (UESFRC). Furthermore, the compressive strength of 0.5% and 1% UESFRC increased by 16.3% and 31.3%, respectively, while the flexural strength increased by 37.1% and 47.9%. Moreover, toughness increased by 58.2 and 69.7 times, respectively. These findings offer an effective solution for future emergency applications in public works.

• Asian Journal of Turfgrass Science
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• v.15 no.2
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• pp.39-50
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• 2001

This research was designed to develop the rapid propagation technology of zoysiagrass using carpet production and to provide turf-growing farmers with efficient cultivation methods thor carpet production. Turfgrass cultivar tested in cadet production by seeding was Z. japonica cv. Zenith. Since the surface coverage rate reached to 85% in 2 months after seeding at the rate 6g/$m^2$ in the early part of July, carpet production using ‘Zenith’seeds would be possible to produce within within the same year. Thrfgrasses tested in carpet production by vegetative propagation were Z. japonica, medium type Z. matrella, fine type Z. matrella, and medium type Z. japonica. Planting rates of vegetative parts (sprigs) were 1.2L/$m^2$, 2.4L/$m^2$, 2.5L/$m^2$, and 5L/$m^2$. Two different sizes of sprig were used; 1~2 nodes and 3~4 nodes. Surface coverage rate was 90% in one year after planting at the rate of 2.5L sprigs of medium type Z. japonica. Therefore, the use of sprigs with 3~4 nodes at the planting rate of 2.5L would be suitable for the carpet prodcution. Three months old zoysiagrass carpet (Zenith) was overseeded with Kentucky bluegrass, perennial ryegrass, and tall fescue at two different overseeding rate. Surface coverage rate was the highest (80%) at the plot overseeded with perennial ryegrass that showed the earliest germination. Suitable overseeding species for the rapid sod formation at the early stage of establishment were tall fescue and perennial ryegrass and desirable overseeding time was from early to middle of September.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.555-560
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• 2008

The effects of utilizing evaporative cooling system equipped with tunnel ventilation on postpartum ovarian activities, energy balance and milk production of early lactating dairy cows under hot and humid climates were studied from parturition to 22 wk postpartum. Thirty-four crossbred Holstein-Friesian (93.75% HF$\times$.25% Bos indicus) primiparous cows were randomly assigned to one of two groups. Cooled cows (n = 17; treatment) were housed in the tunnel ventilated barn equipped with evaporative cooling system and uncooled (n = 17; control) were housed in the naturally ventilated barn without supplemental cooling system. Cooled cows had greater (p<0.05) dry matter intake and milk production than uncooled cows. Days to the energy balance (EB) nadir did not differ between groups. However, days to equilibrium EB for uncooled cows was longer (p<0.05) than for cooled cows. There was no significant difference in postpartum anovular condition between cooled and uncooled cows. The interval from parturition to first postpartum ovulation did not differ between groups ($31.4{\pm}4.3$ and $26.1{\pm}3.6$ day, respectively). These results suggest that the evaporative cooling and tunnel ventilation has the potential to decrease the severity of heat stress and improve both milk production and metabolic efficiency during early lactation without affecting reproductive function in dairy cows under hot and humid climates.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.547-559
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• 2016

The objectives of this study were to investigate the effects of excessive soil-water on crop growth and to predict decrease of yields caused by excessive soil-water. The following five crops were selected for investigation: foxtail millet, proso millet, sorghum, adzuki bean, and sesame. These were planted in pots and a soil-water table was set to 10cm for 10 days. Crop susceptibility (CS) factors and stress-day indexes (SDI) were calculated for each crop to estimate effects of excessive soil-water. SDI models were calculated using CS and SDI data for each crop and predicted the yields of crops cultivated in paddy fields. All crops were cultivated in paddy fields with different soil water contents to evaluate the yield-SDI models. Results showed that yields decreased most when crops were affected by excessive soil-water at the early development stage. Decrease of yields was the greatest when the excessive soil-water treatment was applied at early growth stage. In the field experiment, crops from soils with the greatest soil-water content had the smallest yield, while ones from soils with the smallest soil water contents showed the greatest yields. Observed yields from the field and predicted yields from SDI models showed the least correlation for proso millet, foxtail millet, and adzuki bean and the greatest correlation for sesame. In conclusion, proso millet, foxtail millet, and adzuki bean were more susceptible to soil water than other crops, while sorghum and sesame were more suitable to cultivation in paddy fields.

• Journal of Forest and Environmental Science
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• v.19 no.1
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• pp.48-68
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• 2003

There have been some problems of high labor. low productivity in the existing systems of bonsai cultivation. This study was conducted to cultivate a large quantity of hig-quality bonsai through the development of bottom irrigation system and management method. Bonsai placed on the FRP bed were grown very well by bottom irrigation system compared with direct watering and sprinkler system. It was concluded that bottom irrigation system was possible to reduce considerable manual labor and produce mass production of high-quality bonsai within shorter periods. This research was finally found that the growth was significantly better and earlier production was certain in the vinyl house, had another advantage which could cultivate less cold-resistant species and therefore broadened a range of species selection for market supply. Cultivation techniques by the use of vinyl house and bottom irrigation system developed was quite effective for early production of bonsai as well as for high productive and value added. This project developed a new practical techniques and systems which can make mass and early production of bonsai with high quality through input of less labor. Interest in bonsai is now expanding in landscape horticulture and other fields concerned, and bonsai export of our country is also increasing. Results from this research will make a great contribution to enhancing of bonsai cultivator's competitive position in world markets and to improving of their annual income.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.865-871
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• 2012

Because of the increasing cost of oil and natural gas, energy production technologies using coal, including synthetic natural gas (SNG) and integrated gasification combined cycle (IGCC), have attracted attention because of the relatively low cost of coal. During the early stage of a project, the developer or project owner has many options with regard to the selection of a gasifier. In particular, from the viewpoint of feasibility, the gasifier is a key factor in the economic evaluation. This study compares the technical aspects of gasifiers for a real SNG production project in an early stage. A fixed-bed slagging gasifier, wet-type entrained gasifier, and dry-type entrained gasifier, all of which have specific advantages, can be used for the SNG production project. Base on a comparison of the process descriptions and performances of each gasifier, this study presents a selection guideline for a gasifier for an SNG production project that will be beneficial to project developers and EPC (Engineering, Procurement, Construction) contractors.

• Research in Plant Disease
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• v.12 no.1
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• pp.1-4
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• 2006

During visiting North Korea from 2001 to 2005, I have had a few chances to observe and discuss several North Korean scientists for the seed production program and also, the occurrence of potato pests. Healthy seed production, especially in the early generations, e.g. the production of virus-free starting materials as well as in vitro pre-basic seeds (G0) by hydroponics and basic seeds under netted houses according to her new national seed potato program of Academy of Agricultural Science, Pyongyang, North Korea, has been done well so far. Some major pests occurred, however, in the early generations such as pre-basic seed (G0) in greenhouse, basic seed (G1) in screenhouse, foundation seed-I (G2) and even ware potatoes in the fields are Phytopitthora infestans, Spongospora subterrunea, Ralstonia solanacearum, Pythium spp. and some viruses such as Potato virus X, Potato virus Y, Potato leafroll virus, and also larger potato ladybeetle, greenhouse whitefly and potato tuber moth. Therefore, the success of healthy seed production in North Korea will be thoroughly depended on the pest control and the multiplication of virus-free seed stocks in the isolated areas, especially where no infected potatoes are grown.

• Journal of Plant Biology
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• v.17 no.2
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• pp.53-62
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• 1974

A study was made on the primary production of Lake Changjamot during the spring season of 1973 by menas of the oxygen method. The stratification of temperature and dissolved oxygen were formed in May with the stratified structure of phytoplankton. The range of Secchi disc transparency was from 0.8m to 2.3m during the nine months of this investigation, which was begun in January, 1973. The value was lowest in early June when the phytoplankton blooming reached the peak. The concentration of PO4-P, NH3-N, NO3-N and NO3-N was reduced at the beginning of the phytoplankton blooming and increased again after May except PO4-P. It might have been caused by the inflow of the nitogenous fertilizer from the surrounding agricultural area since May when farming was started. The total amount of chlorophyll-a in the entire water column varied from 25mg/$m^2$ to 277mg/$m^2$ from January till September with the maximum value occurring in early June. These values show a considerable eutrophication of the in comparison with the data obtained in 1969. The daily gross production in the lake varied from a low of 655mgC/$m^2$ to a high of 2,859 mgC/$m^2$ during the spring season and this corresponds to the variation of the amount of chlorophyll. The total amount of daily respiration varied from 650mg C/$m^2$ in winter to 2,307 mg C/$m^2$ in late spring and exceeds gross primary production especially in late May showing the negative balance of daily production and consumption of organic material at that time. In conclusion, Lake Changjamot is a fairly productive and a moderately autotrophic lake and has been eutrophicated much during the past four years.