• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.509-509
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• 2011

Superhydrophobic surfaces on alloyed steels were fabricated with a non-conventional method of plasma etching and subsequent water immersion procedure. High aspect ratio nanopatterns of nanoflake or nano-needle were created on the steels with various Cr content in its composition. With CF4 plasma treatment in radio-frequence chemical vapor deposition (r.-f. CVD) method, steel surfaces were etched and fluorinated by CF4 plasma, which induced the nanopattern evolution through the water immersion process. It was found that fluorine ion played a role as a catalyst to form nanopatterns in water elucidated with XPS and TEM analysis. The hierarchical patterns in micro- and nano scale leads to superhydrophobic properties on the surfaces by deposition of a hydrophobic coating with a-C:H:Si:O film deposited with a gas precursor of hexamethlydisiloxane (HMDSO) with its lower surface energy of 24.2 mN/m, similar to that of curticular wax covering lotus surfaces. Since this method is based on plasma dry etching & coating, precise patterning of surface texturing would be potential on steel or metal surfaces. Patterned hydrophobic steel surfaces were demonstrated by mimicking the Robinia pseudoacacia or acacia leaf, on which water was collected from the humid air using a patterned hydrophobicity on the steels. It is expected that this facile, non-toxic and fast technique would accelerate the large-scale production of superhydrophobic engineering materials with industrial applications.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.440-447
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• 2014

For this analysis, canopies of slender-spindle 'Hongro'/M9 apple trees were divided into 4 positions: upper, lower, exterior, and interior parts. The photosynthetic rate was highest in the external part of the upper canopy of the tree, where it was 4.5 times higher than in the internal part of the lower canopy. This difference was closely associated with differences in light penetration based on canopy position. Analysis of leaf growth characteristics showed that the leaves situated in the internal part of the canopy were larger and thinner than those in the external part of the canopy. The difference in leaf thickness was mainly due to thickness of the primary layer of palisade tissues (68.5 and $110.3{\mu}m$ for internal and external leaves, respectively). Fruit weight and quality were closely related to the extent of light penetration. Fruit weight, soluble solid content, and red skin color were higher in the fruits from the external part of the canopy. Thus, fruit maturity was delayed in the internal part of canopy. The fruit skin and wax layer were thicker in fruits from the internal canopy than in those from the external canopy. Therefore, our results indicate a need for improved light penetration in internal parts of the canopy and for split harvesting depending on maturity at different canopy positions.

• Korean journal of applied entomology
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• v.18 no.4 s.41
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• pp.153-160
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• 1979

The present experiments were carried out to reduce the population density of adult pine gall midge, Thecodiplosis japonensi,s UCHIDA et INOUYE, by means of spray the sticky agent C-4, on the ground, herbacious plantation and foliar leaf of pine trees at Sanbonli,. Anyang, Kyungido. And also the 3 periods of treatment, such as before 2 weeks( I ), before 1 week (II) from the peak emergence period and peak emergence period (III) were applied. The experimental results obtained were as follows. (1) The formula of selected sticky agent C-4 was $70\%$ of castor oil, $25\%$ of damar resin and $5\%$ of carnauba wax, and it showed the best both on stickiness and duration, and lower phytotoxicity to the host plant. (2) The reduction of population densities of the adult PGM were $68\%$ and 78f: in the G-I and G-II treatment plot respectively, which compared to control, on the ground spray. (3) And the reduction of population densities were $63\%$ and about $90\%$ in the P-I and P-II plot respectively when the agent was sprayed on the herbacious plantation. (4) The rates of gall formation were $32.8\%,\;40.8\%\;and\;59.4\%$ in the spray plots of F-I, F-II, and F-III respectively, and there was no significant difference among the upper, middle and lower parts of the treated host plant in the rates of gall formation. (5) The effective stage of sticky agent application were considered as before one week from the peak emergence period in tile all types of treatment.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.88-96
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• 2005

Paraquat-resistant biotype of Conyza canadensis (L.) Cronq. was determined by chlorophyll loss and random amplified polymorphic DNA (RAPD) analysis and the resistant mechanism was investigated with respect to absorption, translocation, and binding constant. RAPD analysis for paraquat resistant (R) and susceptible (S) biotypes found in a pear orchard revealed that the biotypes possessed remote genetic relationship. Chlorophyll loss, as an indication of paraquat toxicity, of S biotype was 7.8-fold greater than that of R biotype. There were no differences in contents of epicuticular wax and cuticle and amounts of [14C]paraquat penetrating the cuticle between the two biotypes. Little translocation of the herbicide out of the treated leaf was observed in either biotype. Binding constants of paraquat to the cell wall and thylakoid membrane were 7.4-fold and 16.9-fold, respectively, higher in R biotype than in S biotype. The results suggest that the resistance mechanism of C. canadensis biotype is due partly to high binding affinity of paraquat to the cell wall and thylakoid membrane.

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.118-126
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• 2008

In order to find the best compositions of the dimethomorph formulation containing fatty alcohol ethoxylate surfactants as an activator adjuvant and recommend the good management way of the formulations to allow an intended uptake rate, factors affecting foliar uptake of active ingredients into cucumber were investigated and compared each other. Among tested, the most important factors were air temperature in which plants were located after spraying of aqueous formulations containing activator adjuvant, and deposit of wax on the leaf surface of cucumber. Dimethomorph uptake was found to be increased by sunlight. When aqueous formulations had long-polyethoxylated fatty alcohol surfactants, the relative humidity of the room in which the plants were located after spraying with the formulations did not severely influence the foliar uptake. Maintaining a mild temperature and avoiding too strong sunlight after spraying with dimethomorph formulations were found to be resonable management strategies.

• Journal of Ginseng Research
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• v.39 no.2
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• pp.135-140
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• 2015

Background: A leaf cuticle has different structures and functions as a barrier to water loss and as protection from various environmental stressors. Methods: Leaves of Panax ginseng were examined by scanning electron microscopy and transmission electron microscopy to investigate the characteristics and development of the epicuticular structure. Results: Along the epidermal wall surface, the uniformly protuberant fine structure was on the adaxial surface of the cuticle. This epicuticular structure was highly wrinkled and radially extended to the marginal region of epidermal cells. The cuticle at the protuberant positions maintained the same thickness. The density of the wall matrix under the structures was also similar to that of the other wall region. By contrast, none of this structure was distributed on the abaxial surface, except in the region of the stoma. During the early developmental phase of the epicuticular structure, small vesicles appeared on wallecuticle interface in the peripheral wall of epidermal cells. Some electron-opaque vesicles adjacent to the cuticle were fused and formed the cuticle layer, whereas electron-translucent vesicles contacted each other and progressively increased in size within the epidermal wall. Conclusion: The outwardly projected cuticle and epidermal cell wall (i.e., an epicuticular wrinkle) acts as a major barrier to block out sunlight in ginseng leaves. The small vesicles in the peripheral region of epidermal cells may suppress the cuticle and parts of epidermal wall, push it upward, and consequently contribute to the formation of the epicuticular structure.

• Korean journal of applied entomology
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• v.42 no.2
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• pp.119-124
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• 2003

The adult of the Cotton caterpillar, Palpita indica (Saunder) laid eggs more on mature leaves than on aged and developing leaves. They laid more on leaves than on petiole and stem, and more on the adaxial than on the abaxial surface side of the leaves. Larvae of the Cotton caterpillar showed their preference in the order of the cucumber (Cucumis sativus), gourd (Lagernaria siceraria), watermelon (Citrullus lanatus) ＞ oriental melon (Cucumis melon L. var makuwa), wax gourd (Benincasa hispida), melon (Cucumis melo), star cucumber (Sicyos angulatus) ＞ sponge cucumber (Lufa cylindrica), cotton (Gossypium indicum). There were no distinct differences among varieties and lines that were collected and hybridized at the Gochang Watermelon Experiment Station in Korea. There was a positive relationship between the leaf area and the degree of damage by the Cotton caterpillar. The feeding amounts of the Cotton caterpillar excrement were gradually increased to 16-18 days after hatching, after that the amounts of excrement were rapidly decreased.

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.187-198
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• 1988

The second leaves from 30 days old seedlings of two rice cultivars which were selected as tolerant (cv. Chokoto) and susceptible (cv. Weld pally) cultivar were soaked in the concentration of $10^{-6}$, $10^{-5}$, $10^{-4}$ and $10^{-3}M$ of oxyfluorfen for 10, 15 and 22hrs and anatomical characteristics were abserved. Dipping to the solutions were carried out either directly to the attached leaves or to the seperated leaves. Development of any symptoms in epidermis, bundle sheath, mesophyll cells and bulliform cells were microscopically inspected. Both cultivars showed reductionin leaf thickness, but the susceptible ones was more sensitive than the tolerant. The degradation and disappearance of epidermal cell layer, breakage of bundle sheath cells, shrinkage of mesophyll cells and disappearance of bulliform cells were general response as affected by oxyfluorfen treatment. The susceptible cultivars showed such responses at the concentration of $10^{-5}M$ for 10 hrs while tolerant ones $10^{-3}M$, for 10 hrs. Those treatments were more effective in seperated leaves than in attached ones. The epicuticular wax layer of leaves treated as above for 20 hrs was inspected by SEM. Weld pally, the susceptible cultivar (Weld pally) showed rapid cleavage of wax layer under $10^{-5}M$ concentration while the tolerant (Chokoto) showed only minor damage on wax layer at the concentration of $10^{-3}M$.

• Journal of Applied Biological Chemistry
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• v.63 no.2
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• pp.161-168
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• 2020

It is known that different plant species have ability to deposit different amounts of particulate matter (PM) on their leaves and plants can absorb heavy metals in PM through their leaves. Heavy metals in PM can have toxic effect on human body and plants. Therefore, PM on different roadside trees at Chungbuk national University including box tree (Buxus koreana), yew (Taxus cuspidate), royal azalea (Rhododendron yedoense), and retusa fringetree (Chionanthus retusa) was quantified based on particle size (PM_>10 and PM_2.5-10). The metal concentration in PM accumulated on leaves was analyzed using inductively coupled plasma-mass spectroscopy. In this study, the mass of PM_>10 deposited on the surface of the tree leaves ranged from 6.11 to 32.7 ㎍/㎠, while the mass of PM_2.5-10 ranged from 0 to 14.8 ㎍/㎠. The royal azaleas with grooves and hair on the leaf surface retained PM particles for longer time, while the yews and box trees with wax on leaf surfaces accumulated more PM. The PM contained elements in crustal material such as Al, Ca, Mg, and Fe and heavy metals including Cu, Pb and Zn. The concentration of elements in crustal material was higher in the coarser size, while heavy metal concentration was relatively higher in the finer size fraction. The Mn, Cd, Cu, Ni, Pb, and Zn concentrations of leaves and PM_2.5-10 were significantly correlated indicating that PM was taken up through tree leaves.

• Research in Plant Disease
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• v.22 no.3
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• pp.158-167
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• 2016

A pathogen that causes a new disease on green pumpkin in the nursery and the field was characterized and identified. Symptoms of the disease on green pumpkin were water soaking lesions and spots with strong yellow halo on leaf, brown lesion on flower, and yellow spot on fruit. The bacterial isolates from the leaf spot were pathogenic on the 8 curcubitaceae crop plants, green pumpkin, figleaf gourd, wax gourd, young pumpkin, zucchini, cucumber, melon, and oriental melon, whereas they did not cause the disease on sweet pumpkin and watermelon. They were Gram-negative, rod shape with polar flagella, fluorescent on King's B agar and LOPAT group 1a by LOPAT test. Their Biolog substrate utilization patterns were similar to Pseudomonas syringae pv. syringae's in Biolog database. Phylogenetic trees with 16S rRNA gene sequences and multilocus sequence typing (MLST) with nucleotide sequences of 4 housekeeping genes, gapA, gltA, gyrB, rpoD and those of P. syringae complex strains in the Plant Associated and Environmental Microbes Database (PAMDB) showed that the green pumpkin isolates formed in the same clade with P. syringae pv. syringae strains. The clade in MLST tree was in the genomospecies 1 group. The phenotypic and genotypic characteristics suggested that the isolates from green pumpkin lesion were P. syringae pv. syringae.