• Korean Journal of Organic Agriculture
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• v.14 no.4
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• pp.411-420
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• 2006

Indole-3-acetic acid (IAA) biosynthesis by bacteria occurs widely in rhizospheres. Bacterial species able to synthesize IAAmay be exploited for beneficial interactions in crop management systems. The objective of this study was to determine the response of ivyleaf morningglory (Ipomoea hederacea) seedlings to IAA and to an IAA-producing rhizobacterum, Bradyrhizobium japonicum isolate GD3. IAA solution and isolate GD3 suppression of seedling growth measured as radicle length and biomass depended on IAA concentration. Seedling radicle length was significantly reduced by ca. 29% with more than $1.0{\mu}M$ of IAA solution, compared to the control, 48 h after application. The cell concentration at 50% growth reduction ($GR_{50}$) of the seedling radicle was IAA production by isolate GD3 at $10^{4.82}\;cfu$, the cell concentration for 50% growth reduction ($GR_{50}$) of seedling radicle was 0.24 iM, which was much lower than the IAA solution concentration ($117.48{\mu}M$) required for $GR_{50}$. Therefore, excess IAA production by isolate GD3 may be more detrimental to morningglory radicle growth than standard IAA solution. Results confirmed involvement of IAA in suppressive effects of isolate GD3 on morning-glory seedlings grown in a hydroponic system.

• Journal of Ginseng Research
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• v.6 no.2
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• pp.168-203
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• 1982

Effects of soil moisture on growth of Panax ginseng, of various factors on soil moisture, and of moisture on nutrition, quality, physiological disorder, diseases and insect damage were reviewed. Optimum soil moisture was 32% of field capacity with sand during seed dehiscence, and 55-65% for plant growth in the fields. Optimum soil moisture content for growth was higher for aerial part than for root and higher for width than for length. Soil factors for high yield in ginseng fields appeared to be organic matter, silt, clay, agreggation, and porosity that contributed more to water holding capacity than rain fall did, and to drainage. Most practices for field preparation aimed to control soil moisture rather than nutrients and pathogens. Light intensity was a primary factor affecting soil moisture content through evaporation. Straw mulching was best for the increase of soil moisture especially in rear side of bed. Translocation to aerial part was inhibited by water stress in order of Mg, p, Ca, N an Mn while accelerated in order of Fe, Zn and K. Most physiological disorders(leaf yellowing, early leaf fall, papery leaf spot, root reddening, root scab, root cracking, root dormancy) and quality factors were mainly related to water stress. Most critical diseases were due to stress, excess and variation of soil water, and heavy rain fall. The role of water should be studied in multidiciplinary, especially in physiology and pathology.

• Journal of the Korean Society of Safety
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• v.14 no.1
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• pp.78-85
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• 1999

The removal characteristics of H$_2$S from IGCC process over the natural manganese ore(NMO) containing several metal oxides($MnO_x$ : 51.85%, $FeO_y$ : 3.86%, CaO : 0.11%) were carried out in a batch type fluidized bed reactor(I.D.=40mm, height=0.8m). The $H_2S$ breakthrough curves were obtained as a function of temperature, initial gas velocity, initial gas concentration, and aspect ratio. The effect of particle size ratio and particle mixing fraction on $H_2S$ removal were investigated with binary system of different particle size. From this study, the adsorption capacity of $H_2S$ increased with temperature but decreased with excess gas velocity. The breakthrough time for $H_2S$ is reduced as the gas velocity is increased which leaded to gas by-passing and gas-solid contacting in a fluidized bed reactor. The results of the binary particle system with different size in batch experimental could predict to improve the behavior of continuous process of $H_2S$ removal efficiency. The natural manganese ore could be considered as potential sorbent in $H_2S$ removal.

• Archives of Pharmacal Research
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• v.19 no.2
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• pp.112-115
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• 1996

Some antioxidant phenolic compounds exhibit prooxidant activity mainly due to their abilities to reduce $Fe^{3+}\; to\; Fe^{2+}.$ Reducing ability and prooxidant activity of maltol, an antioxidant component of Korean red ginseng, were compared with those of pyrogallol. Maltol at 2 mM did not appreciably reduce$ Fe^{3+}\; to\; Fe^{2+}$ and also failed to reduce nitroblue tetrazolium. Stimulation of hydroxyl radical mediated-deoxyribose degradation by pyrogallol was maximal at 60 .mu.M. Maltol stimulated the deoxyribose degradation to a much less extent, and a similar stimulatory effect was observed at a concentration of more than 100-fold higher than that of pyrogallol. The stimulatory effect of maltol reached a plateau over 1 mM, suggesting the removal of hydroxyl radicals by excess maltol. In bleomycin-$Fe^{3+}$-DNA assay, maltol at 2 mM produced a 2.5-fold increase of the iron-bleomycin-dependent DNA degradation over the basal value, whereas pyrogallol at 10 .mu.M accelerated DNA degradation by ca. 10-fold. Furthermore, maltol inhibited $Fe^{2+}$-stimulated DNA degradation by bleomycin. These results strongly suggested that maltol is an antioxidant with little prooxidant activity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.254-258
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• 2000

Current leads of high $T_{c}$ superconductor were fabricated with Bi excess B $i_{2.2}$/S $r_{1.8}$/C $a_{1}$/C $u_{2}$/ $O_{x}$ composition by rapid cooling method. The dimensions of final samples were fixed 3 mm and 8 mm diameter with 50 mm length each To control uniform density the samples were preformed by CIP(Cold Isostatic Press) process and followed by partial or full melting process after raising up to 90$0^{\circ}C$ for 30min. Plate shaped microstructure was clearly observed adjacent to the Ag tube wall and the size of plate was about 100$\mu$m. However the severe destruction of growth orientation was shown in the inner growth part. critical temperature ( $T_{c}$) was about 53~71K after directional growth while Tc was decreased about 77~80 K before directional growth. After directional growth critical current( $I_{c}$) and critical current density( $J_{c}$) in the specimen of 8 mm diameter at 50 K were about 110 A and 280 A/c $m^2$ respectively.pectively.ely.

• Korean Journal of Metals and Materials
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• v.48 no.9
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• pp.842-846
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• 2010

In the present study, the reduction-diffusion method was employed to produce Sm-Fe alloy powder. It was confirmed that the amount of unreacted ${\alpha}-Fe$ in $Sm_2Fe_{17}$ matrix gradually decreased as the percentage of $Sm_2O_3$ increased. $Sm_2Fe_{17}$ single-phase powder was produced by the reduction-diffusion method with 40% excess $Sm_2O_3$. The Ca and Oxygen contents of the powder were approximately 300 ppm and 1600 ppm, respectively, after washing and acid treatment. By a subsequent nitrogenation, $Sm_2Fe_{17}N_x$ magnetic powders were produced. The coercivity of the powder increased with decreasing of the particle size by ball milling, and the highest coercivity of 2850 Oe was obtained after milling for 10 hours.

• Advances in Energy Research
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• v.4 no.3
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• pp.223-237
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• 2016

The excess use of conventional sources of energy by the industries and power sector result in acute shortage of energy produced by fossil fuel. To overcome this energy crisis, biomass feedstock is used to produce syngas or producer gas. For cleaning the dust particle present in the producer gas cyclone separators are largely used. In this paper we investigate the performance parameters of cyclone separator mainly efficiency and pressure drop for different feedstock. Cyclone performance has been evaluated based on experimentation and empirical approach using Leith and Licht model. The same has also been calculated by using turbulent RSM in Ansys Fluent for Wood and Coconut shell feedstock. Experimental results show that using feed stock with 10 % Calcium oxide (CaO) by weight, the efficiency of cyclone got reduced from 71.87% to 70.75% for wood feed stock, whereas in case of coconut shell, the cyclone efficiency got reduced from 78% to 73.44%. It is also seen that Leith and Licht model and Reynolds stress model (RMS) predicts very close to the particle collection efficiency evaluated by using experimental data.

• Analytical Science and Technology
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• v.36 no.2
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• pp.99-104
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• 2023

Trace elements (TEs) have significant effects on both dental health and human health. Toxic effects are caused by deficiency or excess of TEs. This study was performed to determine levels of toxic and trace elements in incisor and molar teeth sampled from male and female participants residing in the north and south regions of Sudan. The tooth enamel of 18 extracted human teeth was analyzed using particle-induced x-ray emission (µ-PIXE) to determine its elemental profile and distribution. GeoPIXEII software package was used for the analysis of µ-PIXE data. The main elements determined were Na, Mg, P, S, Cl, K, Ca, Mn, Fe, Zn, Co, and Sr which were homogeneously distributed in the areas of the tooth enamel mapped with micro-PIXE.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.2
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• pp.115-127
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• 1973

Leaf discoloration of IR667 lines (tropical) and leading locals (temperate) in fields was classified according to the probable causes and nutritional disorder due to soil reduction in 1972 was investigated. 1. The causes of leaf discoloration in IR667 were low air temperature, soil reduction, seed born, insect bite, nitrogen depression, overdose pesticide, strong wind, early senescence and unknown one. 2. Leaf discoloration due to soil reduction which has been called Sageumbyeong by famers, was caused by the heavy application of $Ca(OH)_2$, compost and poor drainage followed by Zn and K deficiency and Fe toxicity. 3. About 30 days after transplanting deficiency concentration of K and Zn in leaf blade appears to be less than 2.0% and 20ppm respectively, and greater than 200ppm, 500ppm, and 1.0% respectively for toxicity or excess of Fe, Mn and Ca. and in the shoot 2.4% for K, 30ppm for Zn and 800ppm for Fe. The value of K/Ca should be greaterthan 2.0 for health. 4. When plants were damaged by soil reduction the contents of N, P, Ca, Mg, Fe, Mn, Na in shoot were increased and those of K, Zn, Si were decreased. 5. IR667 lines show in shoot higher content of N, P, Ca, Mg, Si, Na, and lower content K, Zn, Fe, Mn and lower root activity than local leading varietles in either healthy or disieased case, indicating IR667 lines are likely more suseptible to soil reduction damage. 6. Normal soil was less than 6.5 of pH and greater than -50 mv of Eh, but pH of problem soil was ranged from 6.7 to 7.4 and Eh from -100 to -190. 7. The root activity (${\alpha}$-naphthylamine oxidation) decreased at early stage of soil redudtion damage, then increased with severity and at the end it decreased again, but IR667 lines showed always lower root activity than local ones.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.25-35
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• 2007

Excess runoff contaminated with N and P can impact the quality of downstream water. It has been known that aquatic plants improve the water quality through their intake of organic or inorganic nutrients. This study was conducted to select aquatic plants having high purification ability for nutrient N and P, and mineral nutrients related to EC such as K, Ca, Na, Cl, and $SO_4$ in raw sewage water in greenhouse. We assessed nutrient phytoremediation potential of alien hydrophyte and hydro-crop as well as native landscape hydrophyte to select suitable aquatic plant applied to artificial wetland and buffering site of stream-side. The amount of irrigation water during whole growing period of aquatic plane ranged from 225 L $m^{-2}$ to 444 L $m^{-2}$. Oryza sativa, Typha orientalis, Zizania latifolia, Aster subulatus, Coix lachryma-jobi var. mayuen, Paspalum disdichum var. indutum which had high biomass consumed the large amount of irrigation water over 350 L $m^{-2}$. As a result of analysis of water purification effect N and P content of shoot biomass, and media soil after experiment, Oryza sativa, Zizania latifolia, Aster subulatus, Coix lachryma-jobi var. mayuen, Paspalum distichum var. indutum showed high purification ability about eutrophication elements such as T-N and T-P. It is presented that Pistia stratiotes, Eichhornia crassipes, and Paspalum distichum var. indutum had excellent purification ability about K, Ca, Na, and Cl. Moreover, Paspalum distichum var. indutum greatly removed $SO_4$ in row sewage water.