• Polymer(Korea)
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• v.26 no.3
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• pp.307-315
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• 2002

Major factors affecting the impact resistance of high impact polystyrene (HIPS), the rubber-toughened grade of polystyrene, are rubber-phase particle size and size distribution, molecular weight, morphology, and degree of grafting. Accordingly, it is important to control or investigate these factors. In this study, the effect of solvent content was analyzed by the morphology and particle size distribution of rubber phase, and final properties in bulk-solution polymerization of HIPS. The prepolymerization time was, first, determined by measuring the evolution of particle size distribution of dispersed phase to explain the phase inversion with time. As the solvent content increased, the size of rubber particle increased and then gradually decreased. Rubber-phase morphology was likely to have higher degree of grafting as the solvent content increased. Rheological and mechanical properties decreased as the solvent content increased because of the decrease of matrix molecular weight due to the chain transfer reaction to solvent and the existence of residual solvent. Nevertheless, the impact resistance seemed to increase when the rubber particle size increased.

• Journal of Marine Life Science
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• v.6 no.1
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• pp.23-30
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• 2021

The differentiation process of male germ cells and sperm morphology of the abalone Haliotis discus hannai were described in ultrastructure. The differentiation process of sperm was divided into four stages: spermatogonium, spermatocyte, spermatid and sperm. The process of differentiation from spermatogonium to spermatocyte did not show significant morphological changes. However, during the spermiogenesis there were distinct morphological changes such as chromatin condensation, morphological changes of the nucleus, and formation of acrosome, midpiece and flagellum. The sperm of the abalone consisted of head, midpiece and tail. The head of approximately 5.3 ㎛ in length was composed of a nucleus of high electron dense and bullet-shaped acrosome. The midpiece was composed of the basal body and mitochondria, and five mitochondria were arranged in single layer around the basal body. The cross section of the tail showed a "9+2" axonemal structure. These morphological and structural features are the result of showing that the sperm of H. discus hannai is a primitive type.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.70-77
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• 2014

In this work, we studied basic characteristics of transmission lines employing various PSS (periodic strip structure) on silicon substrate for application to a miniaturization of RF components. According to the results, the transmission lines employing various PSS showed wavelength shorter than conventional coplanar waveguide due to their strong wave characteristics. Especially, with-contact structure was most effective for a miniaturization of RF component. Concretely, the size of the transmission line employing with-contact was only 4.39 % of the conventional coplanar waveguide, According to the bandwidth extraction result, the bandwidth of the transmission lines employing various PSS structures were wider than 384 GHz. Above results indicate that the transmission lines employing various PSS can be effectively used for application to a broadband and miniature RF component, and especially, with-contact is most effective for a miniaturization of RF components.

• Journal of the Korean Vacuum Society
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• v.16 no.2
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• pp.145-152
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• 2007

The evolution dynamics of nanoscale Ge islands on both Si (001) and (113) surfaces is explored using ultraviolet photoelectron emission microscopy (UV-PEEM). Real-time monitoring of the in-situ growth of the Ge island structures can allow us to study the variation of the size, the shape and the density of the nanostructures. For Ge depositions greater than ${\sim}4$ monolayer (ML) with a growth rate of ${\sim}0.4\;ML/min$ at temperatures of $450-550^{\circ}C$, we observed island nucleation on both surfaces indicating the transition from strained layer to island structure. During continuous deposition the circular islands grew larger via ripening processes. AFM measurements showed that the islands grown on Si (001) were dome-shaped while the islands on Si (113) were multiple-side faceted with flat tops of (113)-orientation. In contrast, for Ge deposition with a lower growth rate of ${\sim}0.15\;ML/min$ on Si(113), we observed the shape transition from circular into elongated island structures. The elongated islands grew longer along the [$33\bar{2}$] during continuous Ge deposition. The shape evolution of the islands is discussed in terms of strain relaxation and kinetic effects.

• Korean Journal of Plant Taxonomy
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• v.38 no.1
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• pp.1-16
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• 2008

Anatomical features of seed coat were examined on Trollius, Calathodes, and Caltha of Ranunculaceae to evaluate the taxonomic circumscription of Megaleranthis saniculifolia, which is monotypic and endemic in Korea. Megaleranthis saniculifolia showed the exotestal type of seed coat exhibiting a well-developed palisade structure in exotesta and its external surface of exotesta cells was concave. On the other hand, the shape of exotesta cells in Caltha was cuboidal and the outer surface was smooth. The exotesta of Calathodes seeds was formed of the palisade structure like M. saniculifolia, but the outer surface of exotesta cells was smooth. The palisade structure was much better developed in the exotesta of Calathodes as well as Megaleranthis seeds than in the exotesta of Trollius seeds. The outer surface of exotesta cells in Trollius was either convex or concave according to the species examined. Since the genera of the subtribe Calthinae of the family display differences in seed sculpturing and the anaotmy of seed coat, these characteristics are useful to access taxonomic relationships among them. The morphological and anatomical features of seed coat suggest that Megaleranthis be possibly allied with Trollius rather than Caltha or Calathodes. Concave surface of seed coat cells and well-developed palisade structure of exotesta are shared by M. saniculifolia and some species of Trollius in common.

• Korean Journal of Heritage: History & Science
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• v.45 no.3
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• pp.4-27
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• 2012

The five capital(五京) was installed in the $Li{\acute{a}}o$(遼) Dynasty. $Sh{\acute{a}}ngj{\bar{i}}ng$(上京) was the main capital city of the $Li{\acute{a}}o$(遼) Dynasty. $Zh{\bar{o}}ngj{\bar{i}}ng$(中京) was the second capital(陪都); and the other three was the capital city with symbolic meaning. The layout of $Sh{\grave{a}}ngj{\bar{i}}ng$ was the '日-shaped plan; this was newly advent structure of ancient Chinese capital city system. $Zh{\bar{o}}ngj{\bar{i}}ng$(中京) was surrounded by multiple ramparts influenced by the $Bi{\grave{a}}nli{\acute{a}}ng$ Fortress (?梁城). Three capitals, Nanjing(南京), $X{\bar{i}}j{\bar{i}}ng$(西京) and $D{\bar{o}}ngj{\bar{i}}ng$(東京), were reconstructed on the foundation of the previously constructed town in $T{\acute{a}}ng$(唐) or Bohai(渤海) Fortress (舊城). The structure and Planning of $Sh{\grave{a}}ngj{\bar{i}}ng$(上京) in the $Li{\acute{a}}o$(遼) Dynasty, had significantly influenced in the capital city planning of the $J\bar{i}n$(金), $Yu{\acute{a}}n$(元) and Qing(淸) Dynasties of China

• Fire Science and Engineering
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• v.33 no.6
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• pp.53-62
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• 2019

A recent trend shows that more buildings are being constructed as mixed-use (residential and commercial) properties for efficient land use. This has led to an increased frequency in the occurrence of fires and the associated potential risks. In particular, in case of high-rise apartments, at least one of the elevators in each building is installed for evacuation purposes separately from the emergency elevator; therefore, for a combined ancillary room and emergency elevator platform situation, the structure is inevitably in series with the evacuation elevator platform. Thus, a proposal for a new type of ventilation zone based on existing national fire safety codes is required to achieve smoke control performance. To this end, the air egress velocity and differential pressure of each ventilation zone are checked using the "CONTAM" software; further, an alternative is proposed to secure smoke control performance for series structures.

• Journal of KIISE:Databases
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• v.32 no.5
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• pp.498-508
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• 2005

A shape data is used one oi most important feature for image retrieval as data to reflect meaning of image. Especially, structural feature of shape is widely studied because it represents primitive properties of shape and relation information between basic units well. However, most structural features of shape have the problem that it is not able to guarantee an efficient search time because the features are expressed as graph or tree. In order to solve this problem, we generate curvature-based morphological graph, End design key to cluster shapes from this graph. Proposed this graph have contour features and morphological features of a shape. Shape retrieval is accomplished by stages. We reduce a search space through clustering, and determine total similarity value through pattern matching of external curvature. Various experiments show that our approach reduces computational complexity and retrieval cost.

• The Research Journal of the Costume Culture
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• v.18 no.1
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• pp.109-117
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• 2010

Knit fabrics are created on diverse machines with diverse knit loops and conditions to make different patterns and fabric types. Dimensional modifications of knit fabrics can also be achieved by numerous methods such as different knit-loop structures, different types of yarns, or different finishing processes including heat setting, steaming, chemical treatment et cetera. This research develops and explores sophisticated three-dimensional knit fabrics by combining the several different knit stitches including rib and purl. This study focuses on 3D knit models created on modern electronic weft (flat V-bed) knitting machines which have capability of individual needle selection. Several samples of the 3D knitted fabrics are also examined in this research. This research furthermore suggests new types of knitted fashion garment made by using the interesting physical effects.

• Language and Information
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• v.4 no.1
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• pp.130-140
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• 2000

이 논문에서는 피동접사 '이, 히, 리, 기'와 결합하는 피동형과 관련된 형태·통사적 문제를 전산적 관점에서 다룬다. 전산처리에서 이러한 피동형의 형태적 문제는 다음과 같다. 첫째, 피동접사 '이, 히, 리, 기'와 결합할 수 있는 타동사 어간의 분포가 제한되어 있다. 둘째, 타동사 어간이 결합할 수 있는 피동접사는 고정접사는 고정되어 있다. 셋째, 피동형 중에 타동사 어간과 피동접사가 결합할 대 형태적으로 변화하는 것들이 있다. '나누다/나뉘다, 모으다/모이다, 잠그다/잠기다, 자르다/잘리다'등이 여기에 해당된다. 이러한 형태적 문제 외에도 전산처리에서 피동형과 관련된 통사적 문제는 다음과 같다. 첫째, 능동형의 타동사가 피동형이 되면서 논항구조도 함께 변화한다. 둘째, 피동문의 행동주가 문장에서 생략되는 경우가 종종 있다. '문제가 쉽게 풀리었다','소리가 잘 들린다'등이 이에 해당된다. 이 논문은 한국어 피동접사 '이, 히, 라, 기'와 결합하는 피동형의 형태·통사적 특징을 전산적으로 처리하는 것이 목적이다. 이를 위해 표상모형으로는 자질구조를, 구현도구로는 Malage를 사용한다.