• Research in Plant Disease
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• v.17 no.1
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• pp.13-18
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• 2011

This study was conducted to establish the efficient screening method for resistant cabbage to Fusarium wilt caused by Fusarium oxysporum f. sp. conglutinans. The resistance degrees of nine commercial cabbage cultivars to the disease were evaluated. Among them, five cultivars (YR-honam, Ogane, Greenhot, Redmat, and Ccoccoma) showing different resistance to the fungus were selected. Then development of Fusarium wilt of the cultivars according to several conditions including root wounding, dipping period of roots in spore suspension, inoculum concentration, and incubation temperature to develop the disease was investigated. Highly resistant cultivars such as 'YR-honam' and 'Ogane' hardly showed change of resistance to the disease by root wounding, dipping period, and inoculum concentration, while disease severity of Fusarium wilt on the cultivars was changed with incubation temperatures ($20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$). When the cabbage cultivars were incubated at $25^{\circ}C$, they represented the most difference of resistance and susceptibility to Fusarium wilt. From above results, we suggest that an efficient screening method for resistant cabbage to F. oxysporum f. sp. conglutinans is to dip the non-cut roots of 14-day-old seedlings in spore suspension of $1{\times}10^7$ conidia/ml for 0.5 hr and to transplant the seedlings to plastic pots with a fertilized soil, and then to cultivate the plants in a growth chamber at $25^{\circ}C$ for 3 weeks to develop Fusarium wilt.

• Research in Plant Disease
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• v.16 no.2
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• pp.148-152
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• 2010

To establish the efficient screening method for resistance of radish to F. oxysporum f. sp. raphani, we investigated the development of Fusarium wilt of two radish cultivars, 'Songbaek' (susceptible) and 'Tokwang' (moderately resistant), according to several conditions such as inoculation methods, inoculum concentrations, and dipping periods of radish roots in spore suspension. By infected soil and soil-drenching inoculation methods, Fusarium wilt did not occur on the seedlings of both cultivars. In root dipping inoculation method using cut or non-cut roots of radish plants, the cut roots were easily infected by the pathogen than non-cut roots. And the disease development of two cultivars represented significant difference in non-cut root method. On the other hand, disease severity of Fusarium wilt on radish seedlings according to inoculum concentration increased in a dose-dependant manner, regardless of dipping periods. Using screening method established from the results, the 41 commercial radish cultivars were evaluated the degree of resistance to F. oxysporum f. sp. raphani. Among them, 6 radish cultivars were resistant, 22 cultivars were moderately resistant, and 13 cultivars were susceptible to Fusarium wilt.

• Resources Recycling
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• v.5 no.3
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• pp.65-72
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• 1996

Colloidal calcium wrbonate(diametcr 0.02-0 09 m~wja s developed to maintain the mamenl of pnriide formatio~>w ~lhoutsurlace trealment. The control factors of particle size and optimum condiliuna for compound fam*tition has not bccn studiedyet. This shldy war aimed at developing a method fur compounding colloidal calcium carbonfcte to cnl~hol cubic calciumcarbonate, and then compounding the b-o types oI precipitated calcium wrbonatc under optimum wndilrans Calc~umhydroxide was calcinated at 1, lWC far two hours, md then hydrated for 30 minutes at t i i O rprn and ambiznt temperahlle.Two-liter suspension was subjected to the contact with carbon dioxide at l5"C, 600 ipxn and C0= injection in the rate of 1 Umin Two types of dcium carbonate(cuhic calcium carbonatc(0 24.9 pm) md collnidd calcium mhnnate (0.02-0 09 pm))were compounded by "wing the concentrations of calcium oxide and ihe suspension were compounded. It was found that theoptimum concentrations of each suspensions were 5 wt % and 2.5 \I*.% respectively. ' h c key control factor af thc parlicle slzcdislribution was the concenkation al the suspension. The size of compounded particles was measured by a Zcla S k r 'fieaverage particle size of the cubic calcium carbonate aas 223.4 nm(0.223 pm), and that of thc colloidal a~lciumc arbonate was93.6 nm (0.093 km). Ihe particle sizc was evenly cantlolled on a stdblc basis in an H, O reaction system.asis in an H, O reaction system.

• The Journal of Engineering Research
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• v.5 no.1
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• pp.73-87
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• 2004

The synthesis and crystallization of amorphous calcium carbonate($CaCO_3$.$nH_2 O$) obtained from gas-liquid reaction between aqueous solution of calcium hydroxide and carbon dioxide at 15~$50^{\circ}C$ are investigated by electrical conductometry, XRD and TEM. The results are as follows: The initial reaction products prior to the formation of precipitated calcium carbonate is amorphous calcium carbonate. The electrical conductivity values in the slurry are decreased during the formation of amorphous calcium carbonate which covers particle surface of calcium hydroxide and retard the dissolution of calcium hydroxide into the solution. that amorphous calcium carbonate is unstable in the aqueous solution and crystallizes finally to calcite by the through-solution reaction. While amorphous calcium carbonate crystallizes into chain-like calcite, the conductivity values are recovered rapidly and the apparent viscosity of slurry containing higher concentration of calcium hydroxide increase. At below pH 9.5, chain-like calcite separates into individual particles to form precipitated calcium carbonate. The formation and synthetic temperature range of amorphous calcium carbonate is most suitable a primary decreasing step(a-step) at $15^{\circ}C$ in the electrical conductometry.

• The Korean Journal of Malacology
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• v.12 no.2
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• pp.99-104
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• 1996

우리나라 동해안에서 주요 양식대상종으로 각광을 받고 있는 가리비의 산란유발은 종묘생산시 생산성을 높이는 가장 중요한 요소라고 할 수 있다. 따라서 본 연구는 자극방법에 따른 가리비의 산란유발 효과와 유생사육에 관하여 조사한 결과, 가리비의 생식소 지수는 4월에 암수 각각 32.4와 33.2로 최고치를 보였고, 정자현탁액 첨가구에서 개체당 백만개 이상과 80%이상으로 가장 좋았다.

• Journal of the KSME
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• v.25 no.4
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• pp.312-319
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• 1985

유탁액(emulsion), 현탁액(suspension), 고분자용액(polymer solution) 및 고분자 용식물(polymer melt) 등의 유동에 대하여는 응력과 속도구배 사이에 선형적인 관계가 성립되지 않는다. 이런 유체들은 뉴우튼유체들의 경우와는 달리 단한번의 점성계수 측정만으로는 완전한 유변학 적(rheological) 특징을 파악할 수 없으므로 이들을 통털어서 비뉴우튼유체(non-Newtonian fluid )라고 한다. 이들의 응력과 속도구배 사이의 비선형적인 관계를 고찰하는 비뉴우튼유체역학은 최근에 빠르게 발전하고 있는 유체역학의 한 분야이며, 고분자 공정, 식품, 생물공학 및 유전등의 여러 산업부문에서 많은 관심의 대상이 되고 있다. 여기서는 뉴우튼유체에서 관찰될 수 없는 비뉴우튼유체의 독특한 유동 현상에 대한 이해를 증진시킴으로써, 비뉴우튼유체역학의 여러 문 제들을 취급하는데 필요한 기본지식을 제공하고자 한다.

• Korean journal of applied entomology
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• v.12 no.1
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• pp.23-27
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• 1973

In an effort to find effective inoculation method of Fusarium nivale, this experiment was conducted. The results obtained are summarized as follows: (1) Distilled water-spore suspension of this fungus was inoculated on rice seedling and the result showed that negligible disease symptoms were observed when the inoculated plants were placed in a moist chamber for one day, whereas considerable symptoms were indicated when kept for two days. (2) After giving physical wounds by wind or wooden stick to the rice seedling, distilled water-spore suspenion was sprayed on them and considerable diseased spots were formed. (3) Sufficient disease occurrence was due to the addition of $1\%$ rice leaf extract, glucose, polypeptone, and yeast extract solution to the spore suspension. (4) In distilled water, spore germination was poor, while in nutrient added solution good germination rate as well as anastomosis was found. (5) A new rice variety Tong-il turned out to be more susceptible to Fusarium nivale than Pung-kwang.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.161-167
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• 2008

Using an experimental method named filtration-permeation, the influence of sedimentation during filtration was studied for the suspensions composed of particles and that of flocs. The average specific cake resistances measured by filtration do not give accurate values because of the sedimentations during filtration, but the permeation data give quite accurate values. The prolonged permeation rates for the cake formed from particulate suspension do not change, but that rate from the floc filtration changes by the sweeping of flocculant. It is proposed that the cake compressibility can be measured with one set of filtration-permeation experiment by step increase of pressure during permeation period. The another experimental method which can shorten experimental time for floc filtration using filtrationpermeation is also proposed.

• Korean Journal of Food Science and Technology
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• v.19 no.3
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• pp.239-244
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• 1987

Rheological properties of 5% starch suspension were investigated using a capillarity tube viscometer. Nonglutinous and glutinous rice starch suspensions at $30-60^{\circ}C$, and $30-55^{\circ}C$, respectively, had no yield stress and showed dilatant flow behavior in the absence or presence of phosphate. However, flow behavior of nonglutinuous starches at $65^{\circ}C$ and glutinous starch at $60^{\circ}C$ was pseudopalastic. Flow activation energies for rice starch suspensions were 0.88-1.45 kcal/mole at $30-50^{\circ}C$ and about 45-73 kcal/mole $60-65^{\circ}C$. Flow activation energy in the presence of phosphate was 90-182 kcal/mole at $60-65^{\circ}C$. Akibare starch had the highest activation energy, and glutinous starch the lowest.

• Korean journal of applied entomology
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• v.23 no.4 s.61
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• pp.242-246
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• 1984

Results obtained from the experiment conducted to find out e relationships between tuber decay, and water potential and bruising in or on the tubers, are summerized as follows ; 1) When potato tubers were bruised or injected with bacterial inoculum, the tubers with high water potential rotted more easily than the tubers with low potential. A big difference in the development of decay between high and low water potential tubers was found. 2) In tubers injected with different levels of inoculum. high water potential tubers were more susceptible to soft rot than low water potential tubers. 3) $ED_{50}$ of inoculum concentration was 8.5(log) at high water potential tubers and 9.8(log) at low water potential. A small difference between low and high water potential was detected. The results of this experiment show that potatoes should be handled carefully and must be dried after harvest to reduce decay development in shipment and storage.