• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.4
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• pp.296-302
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• 2001

Winter cereals are acclimated during wintering, and thereafter their freezing resistance is increased. In order to analyze inheritance and heritabilities for photoinhibition of photosynthesis by high light intensity under low temperature, and to evaluate the relationship between low temperature-induced photoinhibition and winter survival, 4 parental half diallel crosses were used. The detached leaves of 7-8cm long from plants grown for 35 and 55 days were placed on wet filter paper and placed in trays at 5$^{\circ}C$ cold room with 1,200 $\mu$mol $m^{-2}$ $s^{-1}$ PPFD. Chlorophyll fluorescence was measured with a chlorophyll fluorescence system after dark adaptation for 30 min. The Fv/Fm of 35day old plants was reduced from 0.714 in the control leaves to 0.409 and 0.368 following photoinhibitory treatment of 6h and 8h and the CVs were increased from 0.8% to 22.2-22.3%. The Fv/Fm of 55-day old plants was reduced from 0.775 in the control leaves to 0.485 and 0.439 following photoinhibitory treatment of 10h and 12h, respectively. According to half diallel cross analysis, Reno and Dongbori 1 (highly resistant to photoinhibition) was dominant, but Oweolbori (susceptible to photoinhibition) was recessive, and photoinhibition showed partial dominance with highly additive gene action. Dongbori 1 showed the greatest GCA effects for photoinhibition, and GCA/SCA ratios (8.7-22.3 times) indicated that the additive variance for the character was more important. Winter survival in barley crosses was positively correlated with resistance to photoinhibition and significantly fitted by linear regression ($R^2$=0.751$^{**}$-0.779$^{**}$). The chlorophyll fluorescence measured by Fv/Fm has been found to be highly inheritable and very useful in evaluating relative levels of freezing resistance in barley.ley.

• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.137-140
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• 2009

A new poinsettia cultivar 'Noel' was bred by the National Institute of Horticultural and Herbal Science(NIHHS) in 2007. In 2004, a cross was made between 'Gutbier V-10 Amy', a variety with high free-branching habit and light red bracts, and 'Ichiban', a variety with deeply lobed transitional leaves and bright red bracts. 'Noel' was finally selected in 2007 after the investigation of observations on the growth and flower characteristics from 2005 to 2007. 'Noel' has smoothly waving red elliptic bracts. Leafblades are dark green and ovate. The variety has relatively long petioles, and stem color is greenish. 'Noel' has high free-branching ability and plant height is medium. Noel's bracts and transitional leaves are fully colored in 7.5 weeks after short day treatment.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.132-132
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• 2022

The application of direct seeding cultivation reduces time, labor, and cost. However, this application often has poor seedling establishment and leads to lower yield as compared to transplanting system. The tolerance to anaerobic and low temperature germination is important to improve seedling establishment and the wide-spread application of direct seeding method. This study was carried out to evaluate the responses of three japonica cultivars to different temperatures (15℃, 18℃, 21℃, 24℃, and 27℃) and different flooding levels (1 cm, 4 cm, 7 cm, 10 cm) during germination and seedling development. The mean survival percentage significantly increased (P<0.05) when the flooding level decreased and when temperature increased. There were significant effects of the interaction between temperature and water depth on survival percentage and seedling height. When temperature decreased from 27℃ to 15℃, the germination duration significantly increased from 6.4 days to 16.3 days while the germination speed, survival percentage, and seedling height decreased from 5.3 seeds day^-1, 61.9% and 190.6 cm to 2.2 seeds day^-1, 33.2%, and 47 cm, respectively. The increase in temperature under submergence condition was associated with the increased expression of Amy3D and ALDH2a but the decreased expression of ADH1 and PDC1. The results of this research would be used for further studies and breeding programs to improve rice seedling establishment and the application of direct seeding cultivation.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.157-160
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• 2008

Solar receiver in the solar power tower system has a similarity to a boiler of the thermal power plant in many aspects. However Boiler is operated long time without stopping while solar receiver repeats start and stop every day. The objective of this study is to investigate start-up characteristics of solar receiver. The experimental device was constructed in a bench scale. Basic experimental condition of water/steam was set by 25 bar and $223^{\circ}C$. Initially, the heat was added into risers only, then another experiment with input into drum additionally was done. When the heat flux was valid only risers, it took about 300 minutes until the water temperature in drum reached $223^{\circ}C$. Water temperature of drum was increased by $44^{\circ}C$/hr with 91.14 g/s of water circulation. With additional heat input into drum, 200 minutes was required to reach $223^{\circ}C$. In this case temperature was increased $66^{\circ}C$/hr with 96.5 g/s of water circulation.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.6
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• pp.633-640
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• 2008

In this research, the $3.6m^3/day$ scale pilot plant consisting preozonation, coagulation, flocculation, and ceramic membrane processes was operated for long term period to evaluate the validity of ceramic membrane filtration process for treating lake water containing high concentration manganese. The higher concentration of dissolved manganese($Mn^{2+}$) was effectively oxidized to the bigger insoluble colloidal manganese ($MnO^2$) by 1~2 mg/L ozone. The colloidal manganese reacted with coagulant (poly aluminium chloride, PAC) and then formed the big floc. Ceramic membrane rejected effectively manganese floc during membrane filtration. Dissolved organic carbon(DOC) removal was dependent upon $Mn^{2+}$ concentration. While average $Mn^{2+}$ concentration was 0.43 and 0.85 mg/L in raw water, DOC removal rate in preozonation was 26.5 and 13.5%, respectively. The decrease rate of membrane permeability was faster without preozonation than with preozonation while membrane fouling decreased with NOM oxidation by ozone. In conclusion, raw water containing high concentration of manganese can be effectively treated in preozonation-coagulation-ceramic membrane filtration system.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.7
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• pp.19-26
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• 2018

This study tested 25 lightweight aggregate concrete (LWAC) mixtures using the expanded bottom ash and dredged soil granules to examine the compressive strength gain of such concrete with different ages. The test parameters investigated were water-to-cement ratios and the natural sand content for the replacement of lightweight fine aggregate. The compressive strength gain rate in the basic equation specified in fib model code was experimentally determined in each mixture and then empirically formulated as a function of the water-to-cement ratio and oven-dried density of concrete. When compared with 28-day compressive strength, the tested LWAC mixtures exhibited relatively low gain ratios (0.49~0.82) at an age of 3 days whereas the gain ratios (1.16~1.41) at 91 days were higher than that (1.05~1.15) of the conventional normal-weight concrete. Thus, the fib model equations tend to overestimate the early strength gain of LWAC but underestimate the long-term strength gain. The proposed equations are in good agreement with the measured compressive strength development of LWAC at different ages, indicating that the mean and standard deviation of the normalized root mean square errors determined in each mixture are 0.101 and 0.053, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.17
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• pp.79-114
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• 1974

Experiments were conducted to clarify the variations of the ecological characteristics under different day-length and temperature conditions inperilla varieties from 1972 to 1973 in the experimental fields of Crop Experiment Station, O.R.D, Suwon. Thirty-six varieties were tested in the field in 1972 under 6 growing seasons differing seeding dates. from April 5th to June 20th with 15-day interval between each seeding. Pot-experiment also were conducted in 1972 and 1973. The seeds of the 6 varieties tested were sown on May 25th. In this pot-experiment natural condition was regarded as a short-day treatment and 100-W incandescent lamps were used for long-day treatment. Three selected varieties were grown under different. temperature treatments in phytotron in Crop Experiment Station. The results obtained are summarized as follows: 1. Most varieties tested flowered around September 6. The days required to flower were shortened gradually as the planting time was delayed. 2. The varieties used were matured around October 6, but the maturity was shortened when planted early. The days required for maturity after flowering was 26 to 30. 3. The growing period was also shortened gradually when planting time was delayed. 4. Plant height was reduced when planting time was delayed. 5. There were little differences in number of valid branches among planting time I, II and III, while the branch number was reduced as the planting time was delayed. 6. The dry matter weight was gradually increased from planting time I to III, while it was rapidly decreased after planting time IV. 7. It was found that the flowering of perilla was little affected by temperature. The varieties, however, were more sensitive to day-length. 8. No clear tendency was found in the plant height, number of valid branches and dry matter weight by the time and period of day-length and temperature treatments. 9. The highest yield was obtained at planting time III(May 5th) and the yield was decreased at either earlier or later planting. 10. 1, 000 grain weight appeared to be heavier as the planting time was delayed. 11. The number of flower cluster was largest at planting time III (May 5th) and it was decreased as planting time was earlier or later than III. 12. The oil content was also highest at planting time III (May 5th). 13. Days to flowering, days to maturity and total growing period and flowering period did not affect the yield much. 14. The number of valid branches, flower clusters, 1, 000-grain weight and dry matter weight were positively correlated with yield. The relationship between these characters and yield were variable depending upon the planting time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.69-89
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• 1981

Stevia (Stevia rebaudiana Bertoni) is a perennial herb widely distributed in the mountainous area of Paraguay. It belongs to the family Compositae and contains 6 to 12 percent stevioside in the leaves. Stevioside is a glucoside having similar sweetening character to surgar and the degree of sweetness is approximately 300 times of sugar. Since Korea does not produce any sugar crops, and the synthetic sweetenings are potentially hazardous for health, it is rather urgent to develop an economical new sweetener. Consequently, the current experiments are conducted to establish cultural practices of stevia, a new sweetening herbs, introduced into Korea in 1973 and the results are summarized as followings: 1. Days from transplanting of cuttings to the flower bud formation of 6 stevia lines were similar among daylengths of 8, 10 and 12 hours, but it was much greater at daylengths of 14 or 24 hour and varietal differences were noticable. All lines were photosensitive, but a line, 77013, was the most sensitive and 77067 and Suweon 2 were less sensitive to daylength. 2. Critical daylength of all lines seemed to be approximately 12 hours. Growth of plants was severely retarded at daylengths less than 12 hours. 3. Cutting were responded to short daylength before rooting. Number of days from transplanting to flower bud formation of 40-day old cuttings in the nursery bed was 20 days and it was delayed as duration of nursery were shorter. 4. Number of days from emergence to flower bud formation was shortest at short day treatment from 20 days after emergence. It was became longer as initiation of short day treatment was earlier or later than 20 days. 5. Plant height, number of branches, and top dry weight of stevia were reduced as cutting date was delayed from March 20 to May 20. The highest yield of dry leaf was obtained at nursery duration of 40-50 days in march 20 cutting, 30-40 days in April 20 cutting, and 30 days in May 20 cutting. 6. An asymptotic relationship was observed between plant population and leaf dry weight. Yield of dry leaf increased rapidly as plant population increased from 5,000 to 10,000 plants/10a with a reduced increasing rate from 10,000 to 20,000 plants/l0a, and levelled off at the plant population higher than 20,000 plants/l0a. 7. Stevia was adaptable in Suweon, Chengju, Mokpo and Jeju and drought was one of the main factors reducing yield of dry leaf. Yield of dry leaf was reduced significantly (approximately 30%) at June 20 transplanting compared to optimum transplanting. 8. Yield of dry leaf was higher in a vinyl house compared to unprotected control at long daylength or natural daylength except at short day treatment at March 20. Higher temperature ill a vinyl house does not have benefital effects at April 20 transplanting. 9. The highest content of stevioside was noted at the upper leaves of the plant but the lowest was measured at the plant parts of 20cm above ground. Leaf dry weight and stevioside yield was mainly contributed by the plant parts of 60 to 120cm above ground but the varietal differences were also significant. 10. Delayed harvest by the time of flower bud formation increased leaf dry weight remarkably. However, there were insignificant changes of yield as harvests were made at any time after flower bud formation. Content of stevioside was highest at the time of flower bud formation and earlier or later harvest than this time was low in its content. The optimum harvesting time determined by leaf dry weight and stevioside content was the periods from flower bud formation to right before flowering that would be the period from September 10 to September 15 in Suweon area. 11. Stevioside and rebaudioside content in the leaves of Stevia varieties were ranged from 5.4% to 14.3% and 1.5% to 8.3% respectively. However, no definit relationships between stevioside and rebaudioside were observed in these particular experiments.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.2 s.115
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• pp.18-25
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• 2006

This study aims to measure and to analyze the thermal environment characteristics of the various permeable pavement materials such as grass pavement (GREEN BLOCK PARK), stone and grass pavement (GREEN BLOCK STEP), stone pavement (GREEN BLOCK MOSAIC) and wood pavement (WOOD BLOCK) under the summer outdoor environment. The thermal environment characteristics measured in the study includes the changes of surface temperature during the day, changes of the temperature on each pavement layer, and long and short wave radiation of each pavement surface. The experimental condition is based on the data on the hottest temperature (August 5, 2005, $34.0^{\circ}C$) of the you. Some of main findings are: 1) The heat environment was worse on the wood pavements than on the stone pavement. This is mainly due to the low albedo of the wood pavements (0.37) while the albedo value of stone pavements is 0.41. Small heat capacity of the wood pavements also contributes to this difference. 2) The heat environment was worse on the stone pavements than on the turf pavements. This was mainly due to the evapotranspiration of the plant growth layer of the turf pavements. 3) The peak surface temperature was the highest on the wood pavements ($56.1^{\circ}C$). The peak surface temperatures on the stone pavements, the stone-grass pavements and the grass pavements were $43.1^{\circ}C,\;40.1^{\circ}C\;and\;37.9^{\circ}C$, respectively. 4) To improve the thermal environments in the urban area, it is recommended to raise the albedo of the pavements by brightening the surface color of the pavement materials. Further studies on the pavement materials and the construction methods which can enhance the continuous evapotranspiration from the pavements surface are needed.

• Journal of Pharmacopuncture
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• v.18 no.4
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• pp.12-19
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• 2015

Objectives: This study was done out to evaluate the effects of Sida rhombifolia methanol extract (SRM) on diabetes in moderately diabetic (MD) and severely diabetic (SD) Sprague-Dawley rats. Methods: SRM was prepared by soaking the powdered plant material in 70% methanol and rota evaporating the methanol from the extract. Effective hypoglycemic doses were established by performing oral glucose tolerance tests (OGTTs) in normal rats. Hourly effects of SRM on glucose were observed in the MD and the SD rats. Rats were grouped, five rats to a group, into normal control 1 (NC1), MD control 1 (MDC1), MD experimental 1 (MDE1), SD control 1 (SDC1), and SD experimental 1 (SDE1) groups. All rats in the control groups were administered 1 mL of distilled water (DW). The rats in the MDE1 and the SDE1 groups were administered SRM orally at 200 and 300 mg/kg body weight (BW), respectively, dissolved in 1 mL of DW. Blood was collected initially and at intervals of 1 hour for 6 hours to measure blood glucose. A similar experimental design was followed for the 30-day long-term trial. Finally, rats were sacrificed, and blood was collected to measure blood glucose, lipid profiles, thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH). Results: OGTTs indicated that two doses (200 and 300 mg/kg BW) were effective hypoglycemic doses in normal rats. Both doses reduced glucose levels after 1 hour in the MDE1 and the SDE1 groups. A long-term trial of SRM in the MD group showed a reduced glucose level, a normal lipid profile, and normal GSH and TBARS levels. In SD rats, SRM had no statistically significant effects on these parameters. Normal weight was achieved in the MD rats, but the SD rats showed reduced BW. Conclusion: The study demonstrates that SRM has potential to alleviate the conditions of moderate diabetic, but not severe diabetes.