• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1184-1186
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• 2009

• Journal of the Korea Society for Simulation
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• v.7 no.2
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• pp.115-123
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• 1998

A simulation is performed to investigate the effect of the pipe supports on the change of the natural frequencies of curved pipe systems containing fluid flow, for different elbow angles and geometry of the pipe systems. Based upon the Hamilton's principle, the equations of motions are derived, and the finite element equation is constructed to solve the corresponding eigenvalue problem. The angles of elbows do not affect the change of the fundamental natural frequency, but affect the change of the third or higher natural frequencies. Without any support, the change of the fundamental natural frequency due to the geometric change is smaller than the change of the second or higher natural frequencies. The more curve parts exist in the pipe system, the less change of lower frequency range, compared with the change of higher frequency range, is observed. Spring supports can be used to reduce the fundamental natural frequency, without change of the second or higher natural frequencies. To avoid resonance, which is critically dangerous from the view point of structural dynamics, the mechanical properties such as stiffness or the location of pipe supports are need to be changed to isolate the natural frequencies from the frequency range of dominant vibration modes.

• Journal of Ecology and Environment
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• v.29 no.4
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• pp.337-342
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• 2006

The total monoterpenoid content of the pine litter layer and the availability of these compounds as inhibitors/stimulators on Polysphondylium violaceum of cellular slime molds were investigated. In order to determine the several monoterpenoids in the natural environment, we examined their concentrations in fresh, senescent, and decaying needles from 3 pine species (Pinus densiflora, P. thunbergii, P. rigida) by litter bag method. Total monoterpenoid content was highest in the fresh needles, but also remained relatively high in senescent needles. The effect of monoterpenoids identified from Pinus plants on the growth of P. violaceum was studied. We tested four concentrations (1, 0.1, 0.01, and $0.001\;{\mu}g/{\mu}L$) of each compound by using a disk volatilization technique. Each compound was treated after germination of spores of P. violaceum. All of the compounds at $1\;{\mu}g/{\mu}L$ concentration had a very strong inhibitory effect on cell growth of P. violaceum. Fenchone at all concentrations, myrcene, verbenone, bornyl acetate, and limonene at low concentrations stimulated the growth of P. violaceum. These results suggest that inhibitory or enhancing effects of selected monoterpenoids depend upon the concentration of the individual compound.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.11
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• pp.145-155
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• 2021

This study examines the export competitiveness of four major natural rubber exporters in the Belt and Road Initiative (BRI) region and investigates the factors affecting bilateral natural rubber export. This study utilized the revealed symmetric comparative advantage (RSCA) to measure export competitiveness. Next, this study employed the gravity model using the Poisson Pseudo Maximum Likelihood (PPML) estimation to analyze the factors affecting bilateral export from the four major natural rubber exporters to 46 countries in the region. The analysis is conducted by using annual data from 2001 till 2018. The findings showed that all four major exporters maintained their export competitiveness. Indonesia and Vietnam notably exhibited increasing trends in the early 2000s. Besides, the market share for Malaysia and Vietnam have increased from 2013 to 2015 with the BRI implementation in 2013. In addition, this study discovered that non-tariff measures (NTM) have a positive and significant impact on the bilateral export of natural rubber. The overall findings strongly indicate that the natural rubber export has increased post BRI announcement. The outcome highlighted the benefits of BRI implementation on the natural rubber export. This study is the first attempt to apply the gravity model on the natural rubber exports within the BRI region.

• Journal of Korea Planning Association
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• v.54 no.1
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• pp.148-158
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• 2019

The purpose of this study is to analyze the impact of earthquake on apartment prices. Many studies have been done analyzing the relationship between natural hazards and residential property prices. Most studies have shown that natural hazards have an negative effect on residential property prices, but some studies have shown that natural hazards have an positive effect on residential property prices. These conflicting analysis result from the lack of considering natural hazard frequency at the analysis site. According to literature reviews risk avoidance tendency are already inherent in prices, thus distorting the relationship between natural hazards and prices. That is, in order to analyze the impact of natural hazards on residential property prices, analysis must be carried out in areas where there has not suffered natural hazard for a long time or where there has been no damage before. Nevertheless, previous studies analyzed areas frequently affected by natural hazards. Gyeongju has been recognized as a safe area from earthquake in the past, an 5.8 magnitude earthquake occurred in September 2016. Analysis results focusing on Gyeongju Earthquake case has shown that the earthquake has affected decrease of apartment prices in hazardous areas, and after earthquake apartment prices have risen over time.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.554-564
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• 2022

The natural circulation phenomena occurring in fully integrated nuclear reactors are associated with a unique formation mechanism. The phenomenon results from a structural feature of these reactors involving upward flow from the core, located in the central-bottom region of a single vessel, and downward flow to the steam generator in the annulus region. In this study, to understand the natural circulation in a single vessel involving a multi-layered flow path, single-phase and two-phase natural circulation tests were performed using the SMART-ITL facility, and validation analysis of the TASS/SMR-S code was performed by comparing the corresponding test results. Three single-phase natural circulation tests were sequentially conducted at 15%, 10%, and 5% of full-scaled core-power without RCP operation, following which a two-phase natural circulation test was successively conducted with an artificial discharge of coolant inventory. The simulation capability of the TASS/SMR-S code with respect to the natural circulation phenomena was validated against the test results, and somewhat conservative but reasonably comparative results in terms of overall thermalhydraulic behavior were shown.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.4
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• pp.746-762
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• 2016

This study considers expression techniques and aesthetic values in the images of head dress reflected in a natural motif. The conclusions of the study are as follows. The first type is the realistic expression (52.4%) such as the reproduction of a natural object's essential form (27.0%), the partial derivation of the natural object (19.3%), and the planarization for the actual image of the natural object (6.1%). The second type is a metaphorical expression (39.0%) which emphasizes the morphological characteristics of nature (18.2%), the structuration of the natural object's silhouette into a three-dimensional or two-dimensional form (11.5%), and the abstract expression of the form in the natural object (9.3%). The third type is a hybrid expression (8.6%) that is a compromise between practical (or metaphorical expressions) so that expression techniques represent a compromise between the natural object's essential form and abstract expression (4.6%) or the combination of the natural object's silhouette into a three-dimensional or a two-dimensional visualization (4.0%). Aesthetic head dress values reflected in the natural motif first indicate a primitive value. This state of natural instinct recreates the natural object or combines part of the biological elements of the natural object to create an inducement to escape from the practical world. The second is amusement in the expression of animals in dynamic and humorous forms creates an illusion of animals being alive with a representative playful enjoyment. The third is abstraction that grant freedom in the observer's aesthetic rational through a reinterpretation of the fashion designer. The fourth is eclecticism where a compromise represents an act of mixing a variety of independent factors to create harmony with the imagery of nature created through the grafting of diverse expression techniques that break away from stereotypes of existing natural objects to create a type of nature that cultivates new values.

• Korean Journal of Agricultural Science
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• v.41 no.3
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• pp.193-203
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• 2014

Natural Monument is a designated cultural property as part of the country. According to Article 2 of the Cultural Properties Protection Act, a national, ethnic and global heritage artificially or naturally formed, with a great historical, artistic, scientific and landscape significance is defined as a cultural heritage. Animals, plants, topography, geology, minerals, caves, biological products and special natural phenomena, having a great of historic, scenic and scientific value, are defined as the monument. According to Article 3 of Cultural Properties Protection Act, the conservation, management and utilization of National Heritage should be kept intact in its original form. So, Natural monuments are managing as retained its original form under the Basic Principles of current law. The highest population of coniferous tree in natural monument plant is ginkgo tree including 22 objects, followed by pines, junipers that order. And in case of broadleaf tree, there are zelkova trees, retusa fringe trees, pagoda trees, cork oaks, silver magnolias and etc. There are many of reported efficacy in available natural monument plants. The efficacy of plant species on pharmaceutical like anti-cancer, anti-diabetic, anti-obesity, antioxidant activity, neuroprotective, improves cholesterol, anti-inflammatory, liver protection and anti-bacterial efficacy, on cosmetics and beauty like the inhibiting formation of skin wrinkles, whitening effect, variety of materials and the efficacy of the proposed utilization of its various papers and etc have been widely reported. Before the Nagoya Protocol enters into force, the future role of the National Research Institute for Cultural Properties Administration of Cultural Heritage should be obtain a legal right to manage the social, cultural and national natural monument with emotional value to the plant genetic resource as a natural monument efficient ways to study and preserve traditional knowledge biological resources by securing a claim to the sovereignty of the material will be ready.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.155-159
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• 2007

A series of new dimesogenic compounds having two identical, terminal Schiff base type mesogens and a central tetramethylene spacer were synthesized. Their thermotropic and mesomorphic properties of the compounds were investigated by differential scanning calorimetry and polarizing microscopy. The compounds with X= -F, -Cl, -Br, -CN and $-OCH_3$ were enantiotropically nematic liquid crystal. In contrast, the compounds with X= -I and $-CF_3$ were non-liquid crystal. The nematic forming efficiency of the groups was in the order of -CN > $-OCH_3$ > -Br > -Cl > -F.

• Fashion & Textile Research Journal
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• v.19 no.5
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• pp.535-546
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• 2017

This study considers direction types and formative characteristics by analyzing natural objets in contemporary fashion window display. The research methods are both literature review and content analysis based on images of contemporary fashion window display. The conclusions of this study are as follows. First, the direction types of natural objets in contemporary fashion window display expand objective outlines by maximizing the morphological form of objects. Second, a rhythmic sense expressed through a gradual repetition of patterns or a sequential arrangement of natural objects. Third, it represents a reversal of image accomplished through a modification of material on the natural objects. Fourth, a new space is created by transforming two dimensional forms of natural objects. The first formative characteristic of natural objects in contemporary fashion window display is exaggeration. This is expressed through either the expansion of the external volume, the collapsed form of natural objects, or the distortion of external colors. Second, it is a dynamics. This makes it possible to recall the dynamic image of the integration of the observer with a priori thinking by systematically sequencing objects or inducing a specific motion. Third, it is an abstraction. This provides an opportunity for the observer to find in a natural beauty by exchanging physical form or reinterpreting characteristic points. Fourth, it concerns eclecticism characteristic that objects created through the mutual fusion of heterogeneous elements indicates an aesthetic inspiration in a limited space by diverting conventional thinking toward natural objects with expansion of consciousness on formative arts.