• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.680-686
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• 2016

In an optical disc archive system, disc insertion process is an important part. Furthermore, dynamic analysis with the contact area between multi-bent leaf spring and a disc should be considered because the contact area is moved when the disc is inserted into the cartridge. In this paper, a finite element model of disc insertion was constructed based on dynamic characteristics, vertical stiffness, and dynamic response. The disc insertion model was validated with the experimental results. To identify the dynamic response of the disc induced by the changed contact area, applied force to the disc and the stiffness of the multi-bent leaf spring were analyzed. As the results, the factors which cause the failure of the disc insertion were investigated.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.27-33
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• 2008

It is shown that the rate of wear can be related to 'index of wear intensity' using a leaf-spring in the disc on disk on wear tests. Since both upper and lower specimens have used the same hardness values, equivalent hardness of 'the index of wear intensity' used the mean hardness value of specimens. This index is derived from the external variables of load, sliding speed and the hardness of the sliding pairs. The wear behavior as the hardness of the sliding elements on the dry wear has been investigated using a disc on disc configuration. The materials of the specimens are used as ten kinds along their hardness. Using experimental data, we figured the relationship between wear rate and index of wear intensity. A newly wear equation had been derived the result using a leaf-spring in disc on disc wear system.

• Korean Journal of Medicinal Crop Science
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• v.14 no.2
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• pp.92-95
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• 2006

A method for plant regeneration via organogenesis from Pelagonium inquinans leaf disc has been developed. Mature leaf explants were collected from field-grown plants and used for the induction of adventitious shoot regeneration on Murashige and Skoog (MS) medium supplemented with 3% (w/v) sucrose plus plant growth regulators. Maximum shoot organogenesis, with $11.8{\pm}1.5$ shoots (98.6%) per leaf disc, was obtained with $2\;mg/l$ $N^6-benzyladenine$ (BA) and $0.5\;mg/l$ ${\alpha}-naphthyleneacetic$ acid (NAA) in 30 days. For rooting, the in vitro proliferated and elongated shoots were excised into 1.5-2 cm in length microcutting, which were plated individually on an half-strength MS (1/2MS) medium supplemented with 2% (w/v) sucrose plus various concentrations of indole-3-butyric acid (IBA). Shoots rooted with a frequency of 100% following culture on 1/2MS medium containing $0.5\;mg/l$ IBA.

• Korean Journal of Plant Resources
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• v.12 no.4
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• pp.253-259
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• 1999

In this study, three simple methods were established to confirm the transgenic potato plants. The leaf disc was used in the first method. After leaf discs of transgenic and non-transgenic potato were transfered into the liquid MS medium with bialaphos 5mg/l, 25 days, the chlorosis occurred in the non-transgenic leaf discs while it could not find in the transgenic leaf discs, In the second method, shoot tips of potato were transferred into MS medium supplemented with 0.5mg/l bialaphos and 0.6% agar. After 7-10 days, a lot of roots developed from the transgenic shoot tip, but the non-transgenic shoot tip was dead. The third method was using chlorophyll contents. Leaf discs were transferred into the liquid MS medium with bialaphos 0.5 mg/l. After 15 days, the content of chlorophyll A in transgenic plant was at least 2.5 times higher than in non-transgenic plant. In addition, the PAT enzyme activity were detected in the transgenic potato, but not detected in normal potato.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.323-329
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• 1993

These studies were conducted to evaluate the five comparative test methods for detecting chemical resistance and to investigate resistant level of field populations of diamondback moth (Plutella xylostella L.). Leaf disc method was practically rocomrnendable because of its rapidity and low CV(l1.4%). Topical application method was a precise replicabiliLy(CV=8.00/0) but it was time consuming and difficult in mampulation. The other 3 methods showed higher CV ranging from 14.9% to 21.4%. Based on $LC_{50}$ values by topical application method, field populations of diamondback moth collected from 4 different regions, Kwangju, Kimhae, Jeju, and Inje to prothiofos showed from 3.3 to 61.1 times higher resistance than the susceptible strain, whereas to cypermethrin, Lhey were from 7.5 to 141.7 times higher than the susceptible. To cartap hydrochloride, they showed from 10.5- to 33.3-fold resistant levels as high as the susceptible. Finally, based on $LC_{50}$ values to Bacillus thuringiensis by leaf disc technique, the resistant levels of the field populations were from 1.9 Lo 8.1 times as compared to the susceptible.

• Journal of Sericultural and Entomological Science
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• v.42 no.1
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• pp.6-9
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• 2000

This study was performed to investigate the catechins which separated from mulberry leaf. The Epicatechin contents in mulberry leves was 1.21${\pm}$0.05 $\mu\textrm{g}$/mg ethylacetate fraction. epigalocatechingallte contents WAS 3.56 $\mu\textrm{g}$/mg ethylacetate fraction. The cathechins (epicatechin and epigalocate-chingallate) separated from mulberry leaf was shown a strong activity to growth inhibition by the concentration of 5 mg/disc on the Clostridium perfringens.

• Korean Journal of Plant Tissue Culture
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• v.26 no.1
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• pp.21-26
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• 1999

These experiments were attempted to introduce rolC gene in the Petunia hybrida cv. Titan white by Agrobacterium mediated. The maximum frequency of shoot regeneration was obtained by 60% on MS medium containing 1.0 mg/L BA, 0.1 mg/L NAA, 200 mg/L kanamycin, 500 mg/L carbenicillin, 30 g/L sucrose, and 8 g/L agar. Kanamycin-resistant calli were selected from petunia leaf discs by cocultivation with Agrobacterium suspension cultures on MS medium. The addition of AgNO$_3$ and KMnO$_4$ in the medium increased the shoot regeneration by 31.3% from leaf disc as compared with non-treated leaf disc. Among clones exhibiting kanamycin resistance, only 3 clones were confirmed by southern hybridization analysis.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.199-204
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• 1999

The effects of temperature stress and paraquat on the superoxide dismutase (SOD) activity and the photochemical efficiency of photosystem II were studied in the leaves of Araliaceae plants. The SOD activity of Acanthopanax koreanum leaf discs increased at 4$^{\circ}C$ and 28$^{\circ}C$, and increased significantly at 4$^{\circ}C$ ,28$^{\circ}C$ and 35$^{\circ}C$ in the presence of paraquat. However, the SOD activity of Dendropanax morbifera leaf discs decreased at 4$^{\circ}C$, 28$^{\circ}C$ and 35$^{\circ}C$ regardless of paraquat treatment. The photochemical efficiency of photosystem II, Fv/Fm, of leaf discs of A. koreanum and D. morbifera fell remarkably at 35$^{\circ}C$. In the presence of paraquat, the Ev/Fm values fell slightly at 4$^{\circ}C$ in A. koreanum leaf discs and at 35$^{\circ}C$, in D. morbifera leaf discs. These results indicate that A. koreanum plants are more resistant to temperature stress or oxidative stress than D. morbifera plants although their photochemical efficiency falls slightly at 4$^{\circ}C$ in the presence of paraquat.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.2
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• pp.67-72
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• 2005

Overwintering capacity, closely related to winter hardiness, of Chinese milk vetch planted with different sowing times and sowing practices was investigated to improve the incorporation into cropping system in Korea. The tolerance to low temperature was evaluated with $LT_50$ using leaf disc leaching method. Dry weight of CMV was reduced remarkably with delayed planting from Sep. 5 to Oct. 20. The differences in tolerance to freezing temperature were not conspicuous among CMV genotypes, however, the differences between genotype (collections at different regions) were due to the plant architecture, mainly to the leaf angle. The crouching genotype collected at central region of Korean peninsula, which showed excellent freezing tolerant, has planophile leaves. The feature of internal constituents of CMV genotypes did not show any noticeable differences with respect to the freezing tolerance which evaluated by leaf disc leaching experiment. To overcome the poor overwintering capacity, tolerant genotype should be developed by selection with considering the plant architecture. The reduction of CMV growth during overwintering period was ameliorated with furrow-sowing under late-sown condition, therefore, when the CMV is inevitably sown late after recommended time, the seeds should be sown on furrow to overcome the cold stress.

• Proceedings of the Korean Fiber Society Conference
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• 1999.04a
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• pp.300-304
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• 1999

A study is strength analysis of a filtering structure for a viscoelastic flowing substance. Conventional segment type filter units comprise an assembly of two or more individual disc segments stacked at their respective hubs on a central common filtrate collection tube within a filter housing. The conventional type's leaf disc is problem that it don't support a high pressure flows. Therefore, this study develope new structure filtering model to stand a high pressure flows.