• Journal of Chest Surgery
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• v.32 no.6
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• pp.495-503
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• 1999

Background: We tested the technical feasibility of fetal cardiac bypass and collected baseline data on the fetal hemodynamics and placental functions related to the cardiopulmonary bypass in the fetal lamb model. Material and Method: Eleven fetuses at 120 to 150 days of gestation were subjected to bypass via trans-sternal approach with a 12 G pulmonary arterial cannula and 14 to 18 F venous cannula for 30 minutes. All ewes received general anesthesia with ketamine. In all the fetuses, no anesthetic agents were used except muscle relaxant. Eight served as a group in which placenta was excluded from the extracorporeal circulation by clamping the umbilical cord during the bypass(the oxygenator group) and in the remaining three, the placenta worked as the only source of oxygen supply(the placenta group). Observations were made every 10 minute during a 30-minute bypass and 30-minute post bypass period. No prostaglandin inhibitors were used both in ewes and in fetuses. Result: Weights of the fetuses ranged from 1.9 to 5.2 kg. In the oxygenator group, means of arterial pressure, PaO2, atrial pressure, heart rate, and bypass flow rate ranged 69.8 to 82.6 mmHg, 201.7 to 220.9 mmHg, 4.1 to 4.3 mmHg, 169 to 182/min, and 140.3 to 164.0 ml/kg/min, respectively during bypass, but rapid deterioration of the fetal cardiac functions and the placental gas exchange was observed after the cessation of bypass. In the placenta group, means of arterial pressure decreased from 44.7 to 14.4 mmHg and means of PaCO2 increased from 61.9 to 129.6 mmHg during bypass. Flow rate was suboptimal(74.3 to 97.0 ml/kg/min) during bypass. All hearts fibrillated immediately after the discontinuation of bypass. Conclusion: In this study, the technical feasibility of fetal cardiopulmonary bypass was confirmed in the fetal lamb model. However, further studies with modifications of the bypass including an addition of prostaglandin inhibitor, an application of the total spinal anesthesia on the fetus, a creation of more concise bypass circuit, and a use of active pump are mandatory to improve the outcome.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.37-47
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• 2006

This work proposes a 10b 25MS/s $0.8mm^2$ 4.8mW 0.13um CMOS A/D Converter (ADC) for high-performance wireless communication systems such as DVB, DAB and DMB simultaneously requiring low voltage, low power, and small area. A two-stage pipeline architecture minimizes the overall chip area and power dissipation of the proposed ADC at the target resolution and sampling rate while switched-bias power reduction techniques reduce the power consumption of analog amplifiers. A low-power sample-and-hold amplifier maintains 10b resolution for input frequencies up to 60MHz based on a single-stage amplifier and nominal CMOS sampling switches using low threshold-voltage transistors. A signal insensitive 3-D fully symmetric layout reduces the capacitor and device mismatch of a multiplying D/A converter while low-noise reference currents and voltages are implemented on chip with optional off-chip voltage references. The employed down-sampling clock signal selects the sampling rate of 25MS/s or 10MS/s with a reduced power depending on applications. The prototype ADC in a 0.13um 1P8M CMOS technology demonstrates the measured DNL and INL within 0.42LSB and 0.91LSB and shows a maximum SNDR and SFDR of 56dB and 65dB at all sampling frequencies up to 2SMS/s, respectively. The ADC with an active die area if $0.8mm^2$ consumes 4.8mW at 25MS/s and 2.4mW at 10MS/s at a 1.2V supply.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.388-398
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• 2020

Watermelon yield mainly depends on soil water content controlled by irrigation in a plastic greenhouse. In this study, we investigated the effect of different soil moisture contents affected by irrigation starting point on growth, yield, and physiological responses of small-sized watermelons. Irrigation was initiated at 5 different levels of soil water content as a starting point with soil moisture detecting sensor after 14 days of transplanting, and stopped at 7 ~ 10 days before harvest. These treatments were compared with the conventional periodic irrigation as control. When soil had the lowest moisture content (-50 kPa), the overall shoot growth was retarded, but the root length and root dry weight increased. The photosynthetic parameters (photosynthetic rate, stomatal conductance, and transpiration rate) of watermelon leaves decreased significantly in the lowest soil moisture content (-50 kPa). On the other hand, the photosynthetic rates of watermelon leaves grown with irrigation starting point between -20 and -40 kPa were observed to be higher than those of other treatments. Fruit set rate and marketable fruit yield increased significantly at -30 kPa and -40 kPa. Proline, abscisic acid (ABA), total phenol and citrulline, which are known to contribute to stress tolerance under drought condition, increased as soil water content decreased, particularly, the largest increases were recorded at -50 kPa. From these results, it was found that an appropriate water supply adjusted with an irrigation starting point between -30 and -40 kPa could help to keep favorable soil water content during the cultivation of small-sized watermelons, promoting the marketable fruit production as well as inducing the vigorous plant growth and reproductive development.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.211-216
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• 2011

This study was carried out to clarify precise $CO_2$ demands of paprika plants (Capsicum annumm L.) by measuring photosynthesis rates of the leaves in high, low positions, and the $CO_2$ consumption of a whole plant in a large sealed chamber. A photosynthesis measuring system (LI-6400) was used to measure the photosynthetic rates of the leaves located in different positions. A large sealed chamber that can control inside environmental factors was developed for measuring $CO_2$ consumption by a whole paprika plant. With increase of radiation, photosynthetic rates of the leaves in higher position became larger than those in lower position. The $CO_2$ consumption by the plant was estimated by using decrement of $CO_2$ concentration from initial level of 1500 ${\mu}mol{\cdot}mol^{-1}$ in the chamber with increase of integrated radiation. A regression model for estimating $CO_2$ consumption by the plant (leaf area = 7,533.4 $cm^2$) was expressed with integrated radiation (x) and was suggested as $y=-0.06234+3.671^*x/(2.589+x)$ ($R^2=0.9966^{***}$). The photosynthetic rate of the whole plant measured in the chamber was 3.4 ${\mu}mol\;CO_2{\cdot}m^{-2}{\cdot}s^{-1}$ under 300 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ light intensity, which is in-between photosynthetic rates of the leaves in high and low positions. For this reason, some differences between required and supplied $CO_2$ amounts in greenhouses might occur when depending too much on photosynthetic rates of leaves. Therefore, we can estimate more accurately $CO_2$ amount required in commercial greenhouses by using $CO_2$ consumption model of a whole plant obtained in this study in addition to leaf photosynthetic rate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.1
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• pp.52-64
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• 1970

Fingerlings hatched from the eggs of the puffer, Fugu rubripes, which were spawned on May 21, 1969, and were cultivated. The results of their growth during 150 days, until October 25th, are summarized as follows: 1. The eggs began to hatch after 163 hours, at a water temperature of 15.9 to $17.4^{\circ}C$, and the hatching rate was $61.56\%$. 2. They reached the post-larval stage 6 to 7 days after hatching, and at this time a high mortality occurred. The mortality rate was 57.26 to $68.0\%$. 3. Sixteen days after hatching some of the larger fingerlings (6.7mm in total length) began attacking some of the smaller ones (4.6mm in to total length). 4. Twenty five to twenty eight days after hatching, the fish changed their food, and at this time a second high mortality occured. The total mortality rate amounted to 90.7 to $90.9\%$ of the total hatch. 5. After the fingerling stage. cannibalism occurs. The fish usually attack the caudal part of other fingerlings. It occurs regardless of body length and when the food supply is short. 6. The food coeffiicient at the age of 46 days (when body length is 53 to 68 mm) was 5.5 for short-necked clams, 8.5 for earth-worms, and 8.7 for fishes. 7. A third hish mortality occurred 53 to 63 days after hatching, the total mortality amounting to 95.76 to $97.34\%$, and the main cause of the mortality was found to be rickets resulting from nutritional deficiency 8. The growth rates were as follows: 2.68mm just after hatching, 3.84mm at the age of 10 days; 7.96mm after 25 days; 20.96mm or 130mg after 40 days; 73.68mm or 9.06g after 80 days: and 123mm or 31.8g after 150 days. 9. The water temperature during the above period was 15.7 to $28.4^{\circ}C$ with an average of $22.10^{\circ}C$ and the salinity was 25.53 to $34.50\%$ with an average of $32.07\%$, 10. The young of this species could endure well a wide range and sudden rise in salinity, and could survive easily when the salinity suddenly fell to $5\%$, but a considerable mortality occured when it fell to $3\%$. 11. When the fish were tranferred directly to fresh water from normal sea water they died out in 9 hours and 40minutes. However, when transferred from water of $5\%$ salinity at which they were reared for 54 days, they survived for 60 hours and 40 mimutes longer than in the former case.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.187-193
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• 1996

To supply seeds with a good quality as plant materials for herbicide screening and to know whether the germination characteristics could be associated with a differential response to herbicides, germination characteristics and differential responses to herbicides were investigated with 3 species of a genus Setaria ; Yellow foxtail(Setaria glauca P. Beauv, SETGL), Giant foxtail(Setaria faberi Hetrm, SETFA), and Green foxtail(Setaria viridis P. Beauv, SETVI). Degree of dormancy was high in the order of SETGL, SETVI and SETFA. The dormancy of SETGL seed was relatively well removed by room temperature and drying storage, but SETFA and SETVI by low temperature and wetting storage(stratification). For breaking dormancy of SETGL, SETVI and SETFA, it was necessary for being kept under the above storage conditions for at least 2, 4 and 4-5 months, respectively. When the dormancy-breaked seeds were transfered to low temperature($4^{\circ}C$) and drying condition, SETGL showed germination rate of 96% even after 2 month storage. However, SETVI and SETFA showed a decreased germination of 54% and 69%, respectively, with a decreased velocity of germination, indicating that secondary dormancy might be induced. On the other hand, a significant change in germination rate was not observed as the seeds were transfered to room temperature($25^{\circ}C$) and drying condition. The germinability of SETGL seed began to decline from 6th year after storage in room temperature and drying condition. All of 3 species showed relatively high germination rate at alternating temperature of $30^{\circ}C$/$20^{\circ}C$(14hr/10hr) and their germination were not increased by light. All of 3 species exhibited similar responses to cycloxydim, sethoxydim and primisulfuron in greenhouse experiment. In contrast, SETVI and SETFA were relatively susceptible to fenoxapropethyl, SETFA to fluazifop-butyl, SETGL and SETFA to clorimuron-ethyl, and SETGL to EK-2612. The difference in herbicidal response among 3 species was the highest in the treatment of EK-2612. These results suggest that there is no a consistent tendency in responses of 3 species to herbicides which have the same target site. And the relationship between germination characteristics and differential responses to herbicides was not found.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.454-460
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• 2019

The purpose of this study is to analyze the distribution characteristics of mist spray particle size by devising a rotary mist spraying device to develop the evaporative salt water desalination system. The rotary mist spraying device was consisted of a BLDC sirocco fan, a spinning fan, a fan fixed shaft and a salt water supply device etc. In this study we analyzed the characteristics of spray particle size and distribution according to the variation of sirocco fan surface roughness(Ra, ${\mu}m$), revolutions(rpm) and salt water flow rate(mL/min). When sirocco fan surface roughness(Ra) was in the range of $0.27{\sim}7.65{\mu}m$, the spray particle size was $0.117{\sim}1.360{\mu}m$. And then more than 90% of spray particles were found to be less than $0.50{\mu}m$. When sirocco fan surface roughness(Ra) was in the range of $12.70{\sim}22.84{\mu}m$, the spray particle size was $2.51{\sim}184.79{\mu}m$ and more than 98% of spray particles were found to be less than $13.59{\mu}m$. To analyze the effect of fan rotation speed on the size and distribution of spray particles, when surface roughness Ra was fixed $0.27{\mu}m$ and fan rotation speed and salt water flow rate was respectively changed at 3,800~5,600 rpm and 2.77~8.28 mL/min, spray particle size was $0.314{\sim}0.541{\mu}m$. And when salt water flow rate was 9.74 mL/min and fan rotation speed was 3,800~5,200 rpm, spray particle size was in the range of $29.29{\sim}341.46{\mu}m$ and in case of 5,600 rpm more than 98.23% of spray particles were in the range of $2.51{\sim}13.59{\mu}m$.

• Journal of the Korean Society of School Health
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• v.9 no.1
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• pp.55-67
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• 1996

This research has incorporated a postal survey from the principals, nurse-charging teachers and nurse-teachers of the fiftyfive elementary, middle and high school in Yang-pyeong county area where its supplementary rate of nurse-teachers is less than adequate. It is to analyse the current status of the school health service in the area and to come out with a plan to improve the school health program through the participations of the health related experts of the local community. The survey was done in the two months of period of April to May of 1994. The result of the survey follows. The student population in the Yang-pyeong county area is 13,998 and the school employee population is 904 which counts for about 19.2% of the whole population of the area. However, the supplementary rate of nurse-teachers is only 10.8% (4 in 55 schools) which is very low in terms of relativity. School health committee only exist in 17% of the whole number of schools in the area and 50 of school health committee answered that their activity do not meet the adequate level. Only 54. 3% of the whole school numbers has included the school health finance in their financial plans and the amount set for the school health finance is about 500,000 wons (100,000-1,600,000 wons). 64.9% of the schools in the Yang-pyeong county area have the permanent nursing room established in the school. But, often than the equipment for a simple physical examinations, their supply of the health related equipments are less than adequate. Particitations of school doctor in the school health service is at only 67.6% which pretty much include only the physical examinations. Nurse-charging teachers consider their utmost important role is to teach health education but, they answered that they spent most of their times and efforts on physical examinations & immunizations. The average number of students visition to the nursing room is 2.5 persons and complains for basic discomfort as headache, concussion, stomachache and indigestion problems and usual pills used are the analgesics and digestives. Physical examination is done in the most schools every year but, 51.4% of nurse-charging teachers answered the physical examination does not really help. About the emergency treatment ability, 75.7% reports that both manpower & equipment are short. The school food services are present in only 8 schools (21.6%) but, 89.2% of nurse-charging teachers answer that there is a definite need of the food service. The survey says that the utmost important environmental health and safety factors are the traffic accidents followed by improper heat system, lighting, the stools and desks that do not consider the student physical status The overall evaluation of school health program reports that there are adequate physical examination, immunization, environmental hygiene, and management of safety but, on the other hand, health education, health councelling & management of nursing room are not managed properly. The principals of the survey pool report shortage of public agency support, lack of understanding of school health, shortage of nursing equipments and school health finance as the barrier factors of school health. The nurse-charging teachers report on the same questions as their less than qualitifying expertise, extraload of work upon the nursing affairs, shortage of nursing equipments & school health finance. The head masters & nurse-charging teachers answered that they are desperate for the meetings of nurse-charging teachers, construction of school health councelling system & training education in order to improve school health and if these are available, they will actively participate in them. After the careful analysis of the survey result, it is apparent that through the relations of the manpowers, establishment of community-oriented school health is definitely in need in rural area where there is low supplementary rate of nurse-teachers and poor school health environment.

• Korean Journal of Construction Engineering and Management
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• v.22 no.4
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• pp.59-65
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• 2021

Since the 2016 "Housing Act Partial Amendment" and the "2018 Housing Comprehensive Amendment Plan", interest in the pre sale system and post sale system of apartment houses has been on the rise. In order to compare the advantages and disadvantages of the pre sale system and the post sale system of apartment houses, and to establish the basis for the institutional policy of the post sale system, a questionnaire survey method was used for tenants of the apartment house from the public side, and issues of time and cost. The time series analysis method is intended to suggest an appropriate time for payment of contributions. Accordingly, through a review of existing theories and literature, the post sale system of public and private institutions was organized, and through a questionnaire survey, the path to securing pre sale money, product information of the model house, and the degree of awareness of the effect of the post sale system were investigated. For the post sale fund support and payment method, it is necessary to increase the commercial line for existing financiers from the user's point of view, and it is necessary to operate in consideration of the economic power of the pre sale market by region. Both 60% post sale and 80% post sale have a price range of up to KRW 10 million, and the total interest rate is 5.0%, and the annual interest rate is about 2.8% for 60% post sale, and about 2.1% for 80% post sale, which is lower than the current 3.1%. I need an interest rate. The research is a perception survey targeting a total of 5,213 households in a sample of after sale apartments in public institutions. As the actual values are analyzed using a time series on the effects of market supply and demand and market prices, there is a limit to applying them to prospective residents of private apartments. In addition, to respond to first time tenants, a questionnaire survey was conducted on five complexes that have moved in within the last five years.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.405-417
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• 2022

The purpose of this study was to describe the photosynthetic features of Prunus maximowiczii and Prunus serrulate Lindl. var. pubescens (Makino) Nakai in response to drought stress. Specifically, we studied the effects of drought on photosynthetic ability and photosystem II activity. Drought stress (DS) was induced by cutting the water supply for 30 days. DS decreased the moisture contents in the soil, and between the 10th and 12th days of DS, both species had 10% or less of x., After the 15th day of DS, it was less than 5%, which is a condition for disease to start. We observed a remarkable decrease of maximum photosynthesis rate starting from 10th day of DS; the light compensation point was also remarkable. Dark respiration and net apparent quantum yield decreased significantly on the 15th day of DS, and then increased on the 20th day. In addition, the stomatal transpiration rate of P. maximowiczii decreased significantly on the15th day of DS, and then increased on the 20th day. Water use efficiency increased on the 15th day of DS, and then decreased on the 20th day. The stomatal transpiration rate of P. serrulate decreased significantly on the 20th day of DS, and then increased afterward, while its water use efficiency increased on the 20th day of DS, and then decreased afterward. These results indicate that the closure of stoma prevented water loss, resulting in a temporary increase of water use efficiency. Chlorophyll fluorescence analysis detected remarkable decreases in the functional index (PI_ABS) and energy transfer efficiency in P. maximowiczii after the 15th day of DS. Meanwhile, photosystem II activity decreased in P. serrulate after 20 days of DS. In addition, Ts-Ta, PI_ABS, DI_O/RC, ET_O/RC followed similar trends as those of the soil moisture content and photosynthetic properties, indicating that they can be used as useful variables in predicting DS in trees.