• Journal of Ecology and Environment
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• v.42 no.2
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• pp.50-59
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• 2018

Background: Duodichogamy is the rarest form of dichogamy in angiosperms, which is characterized by flowering in the sequence of male${\rightarrow}$female${\rightarrow}$male. Disentangling factors promoting duodichogamy require the discovery of more duodichogamous species in angiosperms. However, extremely limited information on duodichogamous species makes it difficult to make general conclusions. Given the inflorescence morphology and flowering characteristics, the Meliaceae family is highly likely to contain duodichogamous species. Methods: We selected 48 individuals from 20 populations in Korea and investigated their flower morphology, arrangement of flowers by sexual condition within inflorescences, and flowering phases and duration of male and female flowers of Toona sinensis (Meliaceae) for 5 years (2011-2015) to determine if the species shows duodichogamous flowering. Results: Toona sinensis belonging to Meliaceae possessed functionally unisexual flowers with rudimentary parts of the opposite sex. The floral organs in male were larger than those in female, except for ovary length and width. In dichasium, male flowers were observed on primary or lateral branches, whereas female flowers were borne only on lateral branches. Overall, individuals from six different populations flowered in the male${\rightarrow}$female${\rightarrow}$male sequence, thereby male is blooming far longer than female flowers at the level of individual trees (male vs. female = 17-20 days vs. 2-4 days). Conclusions: This is the first study to report a duodichogamously flowering species, T. sinensis, within Meliaceae. Several flowering characteristics observed from T. sinensis may be important clues used to discover additional duodichogamous Meliaceae species. Short flowering period and relatively small number of female flowers, which is analogous to reduced ovule numbers observed in other duodichogamous species, may intensify male-male competition in T. sinensis. This study contributed to narrowing down potential candidates of duodichogamy based on their geographic distributions and flowering time.

• Korean Journal of Plant Taxonomy
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• v.34 no.1
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• pp.27-35
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• 2004

Three unrecorded fern species from the flora of Korea belonging to family Dryopteridaceae, Ctenitis maximowicziana, Dryopteris lunanensis, and D. dcipiens var. diplazioides, are found along the valley of Mt. Wolgak (alt. 275m) in Gwangju, Korea. C. maximawicziana is well distinguished from the rest of the species in the genus including C. sinii by the color and morphology of scales in basal part of petioles, shape of blades, and the presence of round-reniform shaped indusia. Dryopteris lunanensis is also well distinguished from its close relative, D. atrata, by the number of lateral pinnae, degree of division of first and/or second pinnules in lower pinnae of the blades, and distribution pattern of sori. Dryapteris decipiens var. diplazioides is distinguishable from type variety by degree of division in lower pinnae of the blades. In terms of morphology, var. diplazioides seems to be intermediate between a type variety and D. fuscipes.

• Journal of Environmental Science International
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• v.17 no.11
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• pp.1227-1233
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• 2008

The effect of freeze drying and fixatives in post-treating freeze drying on the morphological properties of the rose (Rosa hybrida L.) petal were investigated for the production of high quality of freeze dried rose. The morphology including form and color of the dried flowers of cut rose were depended on the drying methods. The drying time was extended due to their density and water content, and was shorter in the freeze drying than that in the natural and hot air drying. Freeze dried process for dried flowers took 2 days in a freeze dryer and did not cause shrinkage or toughening of rose petal being dried, preserving its natural shape and color. The diameter of freeze dried flowers showed little reduction compared to fresh flowers. In Hunter color values of petals of freeze dried flowers, L and a values were high and showed little variations in comparison to fresh petals. Freeze drying led to a noticeable increase in anthocyanin contents in petals, suggesting that anthocyanin contents play an important role in the acquisition of freezing tolerance. Exposure of flowers to freeze drying was accompanied by an increase in the carotenoid content. In the post-treating freeze drying, epoxy resin, a fixative, applied alone or in combination to petals of freeze dried flowers showed efficient coating for the protection from humidity and sunlight. Combined application of epoxy and acetone to freeze dried petals permitted maintenance of natural color and excellent tissue morphology, showing color stability and shiny texture in surface of petals. These findings suggest that application of fixatives to freeze dried rose petals improves the floral preservation and epoxy coating provides good quality in the freeze dried flower product.

• Korean Journal of Plant Taxonomy
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• v.35 no.1
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• pp.25-46
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• 2005

External morphology focusing on the flower structure of Korean Platanthera was examined. The genus Tulotis was included to the genus Plathanthera as previously suggested by many workers, because the diagnostic character to distinguish the two genera was not distinct enough. It is revealed that the taxon previously recognized as P. metabifolia was the misidentification of P. chlorantha and P. neglecta should be treated as a distinct species from P. mandarinorum. In result, Korean Platanthera were rearranged into 8 species; P. chlorantha, P. mandarinorum, P. neglecta, P. hologlottis, P. japonica, P. ophrydioides, P. ussuriensis, and P. fuscescens. A key to the species of Korean Plathanthera and taxonomic discussion of each species were provided.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.171.2-171.2
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• 2015

Nowadays, trivalent rare-earth ($RE^{3+}$) ions activated metal oxides have been proved to be excellent host materials due to their various applications. Facile wet-chemical technique have been considered as the best synthetic route due its intensive interest in the preparation of nanostructures. Europium ion doped lanthanum hydroxide ($La(OH)_3:Eu^{3+}$) phosphors were synthesized by the facile wet chemical method using the hexamethylenetetramine (HMTA) as a mediated surfactant. The thermal behavior for the $La(OH)_3:Eu^{3+}$ phosphors was investigated by thermogravimetric and differential thermal analysis method. The morphological studies were measured by scanning electron microscope and transmission electron microscope measurements, indicating three-dimensional (3D) flower-like $La(OH)_3:Eu^{3+}$ nanorod bundles. After subsequent annealing process, the lanthanum oxide ($La_2O_3:Eu^{3+}$) phosphor exhibited similar kind of morphology. The synthesized $La(OH)_3:Eu^{3+}$ and $La_2O_3:Eu^{3+}$ samples were characterized by X-ray powder diffraction and Fourier transform infrared spectroscopy. Furthermore, photoluminescence and cathodoluminescence properties were studied in details.

• Journal of the Korean Ceramic Society
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• v.47 no.2
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• pp.127-131
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• 2010

Biomimetic whisker-like apatite was formed on thermally and NaOH-treated titanium powder in a simulated body fluid (SBF). In the early process of the SBF immersion, the surface structure of the titanium powder was loosened, possibly due to the dissolution of $Na^+$ ions on the surface of the titanium powder into SBF. When immersed for 7 days in SBF, fine precipitates appeared on the titanium surfaces; the coating layer (<200 nm in thickness) consisted of nanostructured, amorphous whisker-like and particulate phase, observed by TEM. With the extension of the immersion time to 16 days, the chrysanthemum flower type morphology of carbonated hydroxyapatite with a nanocrystallinity was developed on the surface of the titanium powder.

• Korean Journal of Materials Research
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• v.25 no.5
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• pp.247-252
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• 2015

The effect of precursor concentration on the structural, morphological, and optical properties of $TiO_2$nano-flowers was investigated in this study. An increase in crystallite size was observed with an increase in the concentration of the precursor (titanium butoxide). The FE-SEM micrographs of the as-prepared samples show a three-dimensional flower-like morphology. The flowers consist of several nanorods coming out of a single core and have very sharp edges. Also, the variation in the aspect ratio of the nanostructure was observed with the concentration of the precursor. The photocatalytic properties of the samples show that the sample that has a high aspect ratio (AR~9) has a much better photocatalytic activity compared to the nano-crystal with a low aspect ratio (AR~6.1). It is believed that the excellent photocatalytic performance and short time synthesis of $TiO_2$nano-flowers using the microwave hydrothermal method can have potential applications in the field of photocatalysis.

• Korean Journal of Plant Taxonomy
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• v.45 no.4
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• pp.380-390
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• 2015

The morphological characters were observed in six taxa in the genus Dioscorea of Korea (D. polystachya, D. japonica, D. nipponica, D. quinqueloba, D. tenuipes, and D. dokoro). The underground structure and the formation of bulbil were useful characters for separating sect. Enanatiophyllum from sect. Stenophora. The important characters for discriminating taxonomic entities were as follows: the position of the anther and the shape of the pistil in the microstructural characters, including the protuberance of the base of the petiole, the shape and color of the flower, the shape of the fruit, and the shape of the seed wing. Based on the results, a key to Korean Dioscorea is provided and the distribution of these species in Korea is described.

• Journal of Powder Materials
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• v.25 no.4
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• pp.309-315
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• 2018

In the present work, we synthesize nano-sized ZnO, $SnO_2$, and $TiO_2$ powders by hydrothermal reaction using metal chlorides. We also examine the energy-storage characteristics of the resulting materials to evaluate the potential application of these powders to dye-sensitized solar cells. The control of processing parameters such as pressure, temperature, and the concentration of aqueous solution results in the formation of a variety of powder morphologies with different sizes. Nano-rod, nano-flower, and spherical powders are easily formed with the present method. Heat treatment after the hydrothermal reaction usually increases the size of the powder. At temperatures above $1000^{\circ}C$, a complete collapse of the shape occurs. With regard to the capacity of DSSC materials, the hydrothermally synthesized $TiO_2$ results in the highest current density of $9.1mA/cm^2$ among the examined oxides. This is attributed to the fine particle size and morphology with large specific surface area.

• The Korea Journal of Herbology
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• v.22 no.1
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• pp.71-79
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• 2007

Objectives : This study was designed to establish a characteristic discrimination of internal and external morphological standard of original plants and herbal states in Polygoni Multiflori and Cynanchi Wilfordii Radix. Methods : In this studies, the external-internal morphological standards were determined by using stereoscope and butanol series. Results: 1. The external characteristics of original plants: Polygonum Multiflorum has alternate leaves, and its flower with white color blooms at the shoot apex or leaf axil. In the other hand, Cynanchum wilfordii has opposite leaves, and its flower with yellowish green color blooms at the leaf axil. 2. The physical characteristics of herbal slates: Polygoni Multiflori Radix is red-brown in outer surface pink-brown in section. In the other hand, Cynanchi Wilfordii Radix is earthly-brown in outer surface greyish white in section. 3. The physical characteristics according to the place of production: Demonstrable difference according to the place of production is not seen. Polygoni Multiflori Radix is brown or dark brown in outer surface, soft $Yellow{\sim}dark$ brown in section. In the other hand, Cynanchi Wilfordii Radix is white in outer surface, $white{\sim}weak$ red in section, and has power type. 4. The internal characteristics: Polygonum multiflorum has hetero-vascular bundle and lignification of cork layer is progressive. In the other hand, Cynanchum wilfordii has not hetero-vascular bundle, and lignification of cork layer is weak. Conclusion: In the future, many fundamental study such as how to discriminate between Polygoni Multiflori Radix and Cynanchi Wilfordii Radix in origin and efficacy will be necessary. Also the standard of discrimination must be specific and distinct in that several kinds of fo-ti has been traded. It is considered the results of this study will be furnish κ I the basis Lo succeeding studies and it is needed to extensive comparative study for the same genus-degree of relatedness.