• Communications of the Korean Mathematical Society
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• v.34 no.3
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• pp.855-861
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• 2019

The geodesics on the round 2-sphere $S^2$ are all simple closed curves of equal length. In 1903 Otto Zoll introduced other Riemannian surfaces with the same property. After that, his name is attached to the Riemannian manifolds whose geodesics are all simple closed curves of the same length. The question that "whether or not the set of Zoll metrics on 2-sphere $S^2$ is connected?" is still an outstanding open problem in the theory of Zoll manifolds. In the present paper, continuing the work of D. Jane for the case of the Ricci flow, we show that a naive application of some famous geometric flows does not work to answer this problem. In fact, we identify an attribute of Zoll manifolds and prove that along the geometric flows this quantity no longer reflects a Zoll metric. At the end, we will establish an alternative proof of this fact.

• Journal of the Korean Mathematical Society
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• v.40 no.4
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• pp.577-593
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• 2003

The Funk transform is defined by integrating a function on the two-sphere over its great circles. We use complex analysis to invert this transform.

• Korean Journal of Plant Taxonomy
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• v.36 no.2
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• pp.153-161
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• 2006

Two Unrecorded species from Jeju Province are reported: Maesa japonica of Maesaceae which is unrecorded family and Cardamine tanakae of Brassicaceae. Monotypic family Maesaceae, is distinguished from Myrsinaceae and Primulaceae by having pedicels with a pair of bracteoles, flowers without staminodia, semi-inferior ovary and indehiscent fruits with many seeds. M. japonica is readily distinguishable from M. salicifolia in China and M. montana var. formosana in Taiwan and Japan by shapes of blades, corolla and bracteoles, the presence/absence of serrulation of leaf margins, ratio of length of corolla tube and corolla lobes, feature and color of fruit surface. C. tanakae is most similar to Korean endemic C. glechomifolia in morphology, however, the two taxa are readily distinguishable by the number of leaflets of cauline leaves, size of terminal leaflets, number of flowers per inflorescence, the presence of whitish hairs on ovary and fruits.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.513-526
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• 2020

The existing preservation methods are difficult to be applied to a large dimension log which is needed for making traditional wooden ship 'Jalur' in Riau Province. Novel techniques to provide the use of readily available species to replace traditional species alternative were investigated. These included infusion and a combination of injection and bandage-wrapping methods for preserving living trees of Balam (Macaranga conifera (Rchb.f. & Zoll.) Müll.Arg.) and Bintangor (Calophyllum soulattri Burm.f.). Water-based boron compounds were applied as wood preservatives. In total, 18 discs from the bottom, middle, and top of four trees and two controls were used. Trees undergoing treatment were also used to see how wood anatomical structure might affect the boron penetration. The overall aim was to identify the best method for use in Jalur manufacturing. The results showed that in infused Balam tree where the hose position for the preservative intake was deep (10-15 cm from the bark), no boron compound was observed in the outer sapwood. Combination of injection and bandage-wrapping method gave higher percentage of boron penetration at bottom and middle of Balam tree. However, infused Bintangor showed 100% boron penetration. The larger vessel diameter, the absence of tyloses, and the simple perforation plates in Bintangor wood were likely to have contributed to the higher penetration of boron. The combination of bandage-wrapping and infusion, or alternatively by infusing the living trees close to the bark, and at as low as position in the stem gives better protection when treatments are applied to living trees.

• Korean Journal of Plant Resources
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• v.34 no.5
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• pp.462-469
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• 2021

Maesa japonica (Thunb.) Moritzi & Zoll. is a rare evergreen shrub that occurs in west Gotjawal, Jeju island, Korea. This study was conducted to investigate effects of an artificial shading on flowering and growth characteristics of M. japonica seedlings. The level of shading had been set to be 35%, 55% and 75% using shading net. The stage of flowering and flowering ratio, seedling height, the number of leaves and stems, leaf area were measured. Flowering timings were delayed by shading. The number of flowering seedlings per plot and inflorescences per seedling were the most in 55% shading level. Tendency of decreased seedling height with increased shading level was shown. The number of leaves and stems were the fewest values in 75% shading level. The increased biomass with decreased shading level was statistically significant. Aboveground and underground biomass were 2.1 and 1.7 times higher in shading 35% than in shading 75%, respectively. Meanwhile, all seedlings in non-shading plots were dead in winter. Such might be speculated as results of the light stress. As a result, we conclude that M. japonica vitally demands the shading for growth and the optimal shading levels for growth and flowering are 35% and 55%, respectively.