• Korean Journal of Materials Research
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• v.22 no.7
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• pp.329-334
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• 2012

Two types of nanoclusters, termed Cluster (1) and Cluster (2) here, both play an important role in the age-hardening behavior in Al-Mg-Si alloys. Small amounts of additions of Cu and Ag affect the formation of nanoclusters. Two exothermic peaks were clearly detected in differential scanning calorimetry(DSC) curves by means of peak separation by the Gaussian method in the base, Cu-added, Ag-added and Cu-Ag-added Al-Mg-Si alloys. The formation of nanoclusters in the initial stage of natural aging was suppressed in the Ag-added and Cu-Ag-added alloys, while the formation of nanoclusters was enhanced at an aging time longer than 259.2 ks(3 days) of natural aging with the addition Cu and Ag. The formation of nanoclusters while aging at $100^{\circ}C$ was accelerated in the Cu-added, Ag-added and Cu-Ag-added alloys due to the attractive interaction between the Cu and Ag atoms and the Mg atoms. The influence of additions of Cu and Ag on the clustering behavior during low-temperature aging was well characterized based on the interaction energies among solute atoms and on vacancies derived from the first-principle calculation of the full-potential Korrinaga-Kohn-Rostoker(FPKKR)-Green function method. The effects of low Cu and Ag additions on the formation of nanoclusters were also discussed based on the age-hardening phenomena.

• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.194-199
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• 2019

Natural disasters destroy decades of human effort and investments, thereby placing new demands on society for reconstruction and rehabilitation. In most case, the natural phenomena triggering the disasters are beyond human control. In order to solve the problems that the information resources can not be shared among disaster management sectors and their work is hard to be coordinated in city, an idea of application of ubiquitous sense network and ICT technology to model the architecture of the disaster prevention system based on the analysis of characteristics of disasters. The proposed algorithm simulated that it is possible to locate the terminal by linking the direction angle and the estimated position that can be confirmed at the time of stopping, even if the movement direction of the terminal does not move in a certain direction with only a smaller number of mobile base stations. We also confirmed that the proposed algorithms analyzed through simulation are more efficient than existing algorithms.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.3
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• pp.209-217
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• 2021

Although forest fires are more often triggered by artificial causes than by natural causes, the combustion conditions that spread forest fire damage over a large area are affected by natural phenomena. Therefore, using partial least squares structural equation modeling (PLS-SEM), which can analyze the dependent and causal relationships between various factors, this study evaluated the causal relationships and relative influences between forest fire, weather, and drought, taking Gangwon Province as our sample region. The results indicated that the impact of drought on forest fires was 27 % and that of the weather was 38 %. In addition, forest fires in spring accounted for about 60 % of total forest fires. This indicatesthat along with meteorological factors, the autumn and winter droughts in the previous year affected forest fires. In assessing the risk of forest fires, if severe meteorological droughts occur in autumn and winter, the probability of forest fires may increase in the spring of the following year.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.242-251
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• 2011

The effects of top and bottom lids on the natural convection heat transfer phenomena inside vertical cylinders were investigated experimentally for $Ra_{Lw}$ from $9.26{\times}10^9$ to $7.74{\times}10^{12}$. Using the concept of analogy between heat and mass transfer, a cupric acid-copper sulfate electroplating system was employed as mass transfer experiments replacing heat transfer experiments. The natural convection heat transfer of both-open cylinders in laminar and turbulent flows was in good agreement with the existing heat transfer correlations developed for vertical plates. The effects of top and bottom lids on the heat transfer rates were very similar to the studies of Krysa et al. and Sedahmed et al. and Chung et al. With the copper lids, the bottom-closed cavity showed the highest heat transfer rates and then followed both-closed, top-closed, both-open ones in both laminar and turbulent flows. However with the acryl lids, the similar trends were observed except that the heat transfer rates for both-open were higher than top-closed one. The use of the copper lids increased the heat transfer rates compared to the acryl lids due to the hydrodynamic interaction of the flows developed for the different heated faces. This study extended the ranges of flow conditions of the existing literatures and proposed the empirical correlations.

• Journal of Korean Academy of Nursing
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• v.30 no.3
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• pp.799-812
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• 2000

This study adopts the phenomenological approach in order to explore the experience of urinary felt by the small island women and to find the meaning and structure of their experience, for the further understanding of them. This study succeeded in detecting five topics and three basic structure from eight participants, and followings are the comprehensive statement of them. The five topics include neglect of care after childbirth, unavoidable life in the tidal flat, shame which cannot be expressed even to their husbands, endless anxiety toward the expected future, and sad(dilemmatic) lived experience. The basic structure is that small island women who have urinary incontinence are apt to regard their disease as a natural destiny of women who fail to get adequate care after childbirth, and something to be endured to live in the seashore. They think of urinary incontinence as something so shameful that they cannot reveal it even to their husband and family. They believe that it even changes their personality since they must always stay alert in order to cope with the situation; for example, when it takes place unexpectedly, like too often to go to toilet, to change the underwears, to wake up in the middle of the night to go to toilet, to try not to laugh loudly, or to have showers. In addition, they accept it as a natural process of aging and incurable disease, and they consider themselves already ruined on the way of becoming uglier. They show dilemmatic abandonment: give it up unwillingly but at the same time think it is natural for others too. The unique experience of small island women with urinary incontinence implied in those statement are inseparable with the specific conditions for survival in the island. Unlike other diseases, it is considered the result of traditionally poor care after childbirth. However this misunderstanding that it is a natural phenomena for all the women who experience childbirth and aging and thereby incurable leads to an undesirable attitude toward urinary incontinence. According to the analysis, environmental conditions specific for small islands make the women there have distinct and unique experience concerned with urinary incontinence. Consequently, the future nursing plan for urinary incontinence in the small island area must be made and enforced with the consideration of these specific phenomenological meanings. Modern Korean nursing has basically been centered to hospital or urban areas. Besides, nursing intervention has long depended upon the research of western countries. This research, however, shows how greatly the regional and cultural characteristics influence the understanding of a certain disease, and is expected to make more specific and in-depth nursing approach enable for those who have urinary incontinence in small islands.

• Corrosion Science and Technology
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• v.4 no.6
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• pp.236-241
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• 2005

Hydrogen induced cracking (HIC) is one of the hydrogen degradation phenomena of linepipe steels caused by $H_2S$ gas in the crude oil or natural gas. However, NACE TM0284-96 standard HIC test method is hard to satisfy the steel requirements for sour service application since it uses more severe environmental conditions than actual conditions. Therefore, in order to use steels effectively, it is required to evaluate HIC resistance of steels in the practical range of environmental severity. In this study, HIC resistance of two high strength low alloy (HSLA) steels being used as line pipe steels was evaluated in various test solutions with different $H_2S$ pressures and pH values. The results showed that the key parameter affecting crack area ratio (CAR) is $H_2S$ partial pressure of test solution when the pH value of test solution is not over 4. Hydrogen diffusivity was not a constant value, but it was rather affected by the hydrogen ion concentration (pH value) in the solution.

• Journal of the Korean Society for Library and Information Science
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• v.31 no.4
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• pp.19-33
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• 1997

The content systems of Shinjung Tongguk Yoji Sungnam(신증동국여지승람, A Korean Geography Published in Chosen Dynasty) consist of 26 items and the main subject comprises administration, military and geography, This book does not suggest a simple geography but a comprehensive bibliography as an administrative guide book of a nation or a military operation manual. In particular, this book is made much of as a more valuable material in elevating the quality of the geographic book since it contained a 'Cheyong(제영)' item and reinforced the fields of humanities which could not be found out in other geography. The verses of Cheyong are recorded in the documents in the Chungchong, Kyungsang and Chulla Provinces, and these recorded verses In the tree provinces are more than half of the whole country's. The objects of recitation in the these verses are related to such natural phenomena and historic relics as the mountains, the livers, the wails and the royal tombs.

• The Journal of the Acoustical Society of Korea
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• v.18 no.3
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• pp.17-26
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• 1999

We present the first speech coarticulation database of Korean, English and Konglish/sup 3)/ named "SORIDA"/sup 4)/, which is designed to cover the maximum number of representations of coarticulation in these languages [1]. SORIDA features a compact database which is designed to contain a maximum number of triphones in a minimum number of prompts. SORIDA contains all consonantal triphones and vowel allophones in 682 Korean prompts of word length and in 717 English prompt words, spoken five times by speakers of balanced genders, dialects and ages. Korean prompts are synthesized lexicons which maximize their coarticulation variation disregarding any stress phenomena, while English prompts are natural words that fully reflect their stress effects with respect to the coarticulation variation. The prompts are designed differently because English phonology has stress while Korean does not. An intermediate language, Konglish has also been modeled by two Korean speakers reading 717 English prompt words. Recording was done in a controlled laboratory environment with an AKG Model C-100 microphone and a Fostex D-5 digital-audio-tape (DAT) recorder. The total recording time lasted four hours. SORIDA CD-ROM is available in one disk of 22.05 kHz sampling rate with a 16 bit sample size. SORIDA digital audio-tapes are available in four 124-minute-tapes of 48 kHz sampling rate. SORIDA′s list of phonetically-rich-words is also available in English and Korean.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.683-688
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• 2001

Cryogenic LNG(Liquefied Natural Gas) which is stored in the cylindrical storage tanks of $100,000m^{3}$ has very complex flow phenomena and the changes of thermal properties with exterior conditions and operation mdoes. These complex thermofluid behaviors are affected by the storage, exterior conditions of LNG, design specifications and heat transfer characteristics of tanks, Also, those have influence on the stable storage and supply of LNG in the storage tanks. Thus this study performed the analysis on the 2-D heat transfer of the tank with exterior conditions, on the Cool Down Process in order to cool down the LNG Storage Tank at the initial normal state, and on the Filling Process considered for incoming and rising of LNG. The analysis on the Mixing LNG Storage was studied too. At last, the visualized program on the complex thermofluidodynamic analysis was developed on the basis of the above analyses. The development of this program becomes to be used to the basic design of the commercial tanks as well as to assure technical skill of the analysis on the thermal stability of the stored LNG in the LNG Storage Tank.

• Communications of Mathematical Education
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• v.21 no.2 s.30
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• pp.125-152
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• 2007

When we teach mathematics in college, we find a lot of mistakes, fallacies and flaws in the solution of the students. In this paper, we presented a variety of examples of mistakes and fallacies, including wrong proofs, misinterpreted definitions and the mistaken use of theory. The examples, taken from different classes and subjects, are based on our own experience of teaching mathematics. As the previous research argued, such mistakes, fallacies and flaws should be considered as natural phenomena in the students' progress and should be analyzed systematically for the more effective education. By providing a wide-ranging examples of mistakes and fallacies, and detailed analyses of them, we emphasized the significance of the analysis of mistakes and fallacies and proposed that more careful attention should be paid on the collection and development of teaching materials in the area of mistake and fallacy analysis. We hope that this study would be a meaningful contribution to the teaching of mathematics in college.