• Communications of the Korean Mathematical Society
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• v.15 no.2
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• pp.357-370
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• 2000

In [6], Cheng-Ye You gave a condition equivalent to the Nielsen number product formula for fiber maps. And Jerzy Jezierski also gave a similar condition for coincidences of fiber maps. The main purpose of this paper is to find the condition for which holds the product formula for Nielsen root numbers N(f;a) = N(f;a) N(fb;a).

• Journal of Bio-Environment Control
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• v.7 no.2
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• pp.139-143
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• 1998

This experiment was conducted to investigate the effect of soil heating on control of root-knot nematode(Meloidogyne incognita Chitwood) by root zone warming system. Root zone was warmed by hot water flowing through pipe set at 35cm depth from the ridge The lowest soil temperatures at 20cm depth were set at 3$0^{\circ}C$, 4$0^{\circ}C$, $50^{\circ}C$ and non-warming. under soil submerging condition and non-submerging condition. Soil heating was done for 5 days(120 hours) from Aug. 1 to Aug. 5. The root-knot nematode juvenile densities of 4$0^{\circ}C$ under submerging condition. and $50^{\circ}C$ under non-submerging condition were 0 which was expected lower than the economic injury level. The contents of OM P$_2$ $O_{5}$, Ca Mg and EC in soil were decreased by root zone warming The EC was considerably lowered under submerging condition.

• Proceedings of the Korean Society of Crop Science Conference
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• 2019.09a
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• pp.21-21
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• 2019

Approximately 80% of rice field in Africa conducts in rainfed (Nishimaki 2017). The rice is damaged by water stress because fields like rainfed lowland repeat drying and humidity of soil because of impossible water control. Then water stress is one of the major limiting factors for decreasing rice yield. So, in initial growth stage, quick and efficient root development is useful way to avoid drought stress by getting water from deeper soil layer with roots elongation as the hypothesis. Daniel et al (2016) reported that NERICA1 and NERICA4 show different patterns of root plasticity for drought stress. NERICA1 has greater development of lateral root in shallow soil layer, while NERICA4 has greater development in deep root elongation to underground. This study was aimed to evaluate the effect of root development in initial growth stage on growing NERICA1 and NERICA4 under different soil moisture condition in rainfed lowland rice field. They were grown in same water condition until 35 days after sowing (35DAS), and after that each varieties were separated in dry and wet condition. The rice plants were grown until 60DAS. The results of soil moisture, the root extension angle, shoot dry weight and bleeding ratio showed that NERICA4 can mitigate dry stress from surface soil compered to NERICA1.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.127-131
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• 2006

Depot have a lagged behind structure in the side of building up the view. With this reason, people have been recognized depot as hatred facility causes to have car noise, air pollution. In the other hand, depot become a underground and complex facility as a higher-value added building, and moreover, it need to understand the environment that depot structure have a specific field condition to apply green roof system. 1) Analysis proper waterproofing material and root barrier apply to depot need root penetrating test method 2) Suggest root barrier and waterproofing material relate to maintain and construction for green roof system 3) Construction condition for depot have crack movement of structure by vehicle vibration and root penetrating force by plant growth

• Natural Product Sciences
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• v.24 no.2
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• pp.103-108
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• 2018

The usage of wild ginseng (Panax ginseng C.A. Meyer) has been limited due to short supply and high price. Therefore, sufficient production as well as efficient extraction of mountain ginseng are required for the development as products. In this study, wild ginseng adventitious root cultures were prepared for efficient production with advantages of fast growth and stable production. Treatment of methyl jasmonate (MJ) to wild ginseng adventitious root cultures increased the extraction yield and antioxidative activity. Further investigation on effect of extraction conditions suggested the importance of ethanol concentration on antioxidative activity and extraction yield of MJ-treated wild ginseng adventitious root cultures. Optimized extraction condition of MJ-treated wild ginseng adventitious root cultures for maximum extraction yield and antioxidative activity was determined using response surface methodology with three-level-three-factor Box-Behnken design (BBD). Extraction of 1 g MJ-treated wild ginseng adventitious root culture with 30 ml of 9% ethanol at $30^{\circ}C$ produced 310.2 mg extract with 71.0% antioxidative activity at $100{\mu}g/ml$. Taken together, MJ-treated wild ginseng adventitious root culture is valuable source for wild ginseng usage and optimized extraction condition can be used for the development of functional products or folk remedies.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.3
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• pp.76-81
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• 2006

The reinforcement of soil shear strength by nylon net as substitute materials simulating a fine root system was evaluated by soil strength parameters(apparent cohesion(c) and internal friction angle(tan${\phi}$), using simple shear tester which clearly depicts shear deformation and controls soil suction. And the results of shear test by using bamboo as a substitute materials simulating a main root system and using nylon net as a substitute materials simulating a fine root system were compared. The reinforcement of soil strength by nylon net are expressed by apparent cohesion more than internal friction angle. In addition the increment of apparent cohesion by nylon net reached a peak in suction 60 $cmH_2O$. Different from with bamboo, the possibility of the change on internal friction angle(tan${\phi}$) caused by the soil water condition was shown in shear strain 20% condition. These results show that the mechanism of reinforcement by substitute materials simulating root system may be different in the condition of various soil water content.

• Journal of Welding and Joining
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• v.27 no.1
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• pp.95-101
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• 2009

In case of manufacturing the high quality welds or pipeline, the full penetration weld has to be made along the weld joint. Thus the root pass welding is very important and has to be selected carefully. In this study, an experimental method for the selection of optimal welding condition was proposed in the root pass welding which was done along the V-grooved butt weld joint. This method uses the response surface analysis in which the width and height of back bead were chosen as the quality variables of the weld. The overall desirability function, which is the combined desirability function for the two quality variables, was used as the objective function for getting the optimal welding condition. In the experiments, the target values of the back bead width and the height are 6mm and zero respectively for the V-grooved butt weld joint of 8mm thickness mild steel. The optimal welding conditions could predict the back bead profile(bead width and height) as 6.003mm and -0.003mm. From a series of welding test, it was revealed that a uniform and full penetration weld bead can be obtained by adopting the optimal welding condition which was determined according to the method proposed.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.328-328
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• 2017

Drought is a major limiting factor that reduces rice production and occurs often especially under recent climate change. Plants have the ability to alter their developmental morphology in response to changing environment, which is known as phenotypic plasticity. In our previous studies, we found that one chromosome segment substitution line (CSSL50 derived from Nipponbare and Kasalath crosses) showed no differences in shoot and root growth as compared with the recurrent genotype, Nipponbare under non-stress condition but showed greater growth responses compared with Nipponbare under mild drought stress condition. We hypothesized that reducing root respiration as metabolic cost, which may be largely a consequence of aerenchyma formation would be one of the key mechanisms for root plasticity expression. This study aimed to evaluate the root respiration and aerenchyma formation under various soil moisture conditions among genotypes with different root plasticity. CSSL50 together with Nipponbare and Kasalath were grown under waterlogged conditions (Control) and mild drought stress conditions (20% of soil moisture content) in a plastic pot ($11cm{\times}14cm$, ${\varphi}{\times}H$) and PVC tube ($3cm{\times}30cm$, ${\varphi}{\times}H$). Root respiration rate was measured with infrared gas analyzer (IRGA, GMP343, Vaisala, Finland) with a closed static chamber system. There was no significant difference between genotypes in control for shoot and root growth as well as root respiration rate. In contrast, all the genotypes increased their root respiration rates in response to mild drought stress. However, CSSL50 showed lower root respiration rate than Nipponbare, which was associated by higher root aerenchyma formation that was estimated based on internal gas space (porosity) under mild drought stress conditions. Furthermore, there were significant negative correlations between root length and root respiration rate. These results imply that reducing the metabolic cost (= root respiration rate) is a key mechanism for root plasticity expression, which CSSL50 showed under mild drought.

• Journal of Ginseng Research
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• v.20 no.3
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• pp.318-324
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• 1996

The effects of light on the growth and ginsenosides production were examined in the hairy roots of Panax ginsen C.A. Meyer induced by Agrobacterium rhizogines A4. The 9rowth of ginseng hairy roots in 1/2MS liquid medium was significantly decreased with an increment of light intensity (1,000~7,000 lux). The growth of hairy roots under 7,000 lux condition was decreased at 17% compared to the dark condition. The production of 7 ginsenosides in hairy root was very high in 3,500 lux condition. The production of ginsenoside-Rg, and Rf increased 3.3 and, 2.4 times respectively as compared to dark condition. The growth of hairy roots was inhibited by blue light, while ginsenosides production was increased. The sucrose demands of hairy roots was examined in light condition(3,500 lux). The growth of hairy roots in 1/2MS liquid medium with various sucrose concentrations(1~4%) was high in IVp sucrose, while ginsenosides production was high in 3% sucrose condition. The growth and ginsenosides production were high when hairy roots were cultured in dark condition for 1 week and then transferred to light condition(3,500 lux) for 4 weeks. It is suggested that ginsenosides production could be accelerated by light intensity of specific wavelength in cultures of ginseng hairy roots.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.294-300
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• 1985

This experiment was carried out to study the root and the other major agronomic traits of barley cultivars at the greenhouse and natural conditions for the accelerating of breeding generation. The barley cultivars tested in this experiment were Kangbori, Olbori and Suwon 18. In early stages, total dry weight of barley was vigorously increased at the greenhouse condition, whereas it was less increased than that of natural condition after heading stages. In dry root weight, it was decreased at natural condition rather than greenhouse condition. The appearance of harvest dry root weight was at four weeks after heading at natural condition and seven weeks after heading at greenhouse condition, respectively. It showed different tendency in T/R ratio, indicating the continuous increased at natural and greenhouse condition, even if there is more or less decrease until tillering stage at greenhouse condition.