• Title/Summary/Keyword: natural phenomena

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A Study on the ZEN(禪) style in Contemporary Fashion (현대 패션에 나타난 젠(zen:禪)양식에 관한 연구)

  • 조정미;김예형
    • Journal of the Korean Society of Costume
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    • v.50 no.6
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    • pp.163-175
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    • 2000
  • This study focuses on the Zen style in contemporary fashion which presents itself as one of the dominant cultural phenomena these days. After investigating the basic concepts and features of the Zen style and examining its birth and development, this study moves on to the ways in which it is characteristically applied for the world of fashion. This study is also performed both by the theoretical research on related books and papers for the explication of main concepts and by the practical research on fashion magazines and works of famous fashion designers for the presentation of more detailed illustration. When we are talking about postmodernism, which is a reaction against or a continuation of modernism, as a cultural dominant shown up in the late twentieth century, the Zen style itself can be regarded as a typical representation of postmodernism in fashion. Although the Zen style can be viewed as sharing the basic principles with minimalism which is a main branch of modernism, it is strongly in line with postmodernism (which is human-centered) in that its fundamental idea is based on emotions and feelings of human beings and the purity of natural world. As above, ZEN is a crossover phenomenon between postmodernism and modernism. In this sense, it is said that within the name of postmodernism the Zen style has satisfied our desire to present our inner world of mind with the help of regional philosophy (in this case Oriental one). The four main aspects of the Zen style in fashion are following : simplicity connected with the Oriental moderation, the use of the Oriental silhouette and detail, the destruction of form, and the nature-friendly attitude. These will be under close examination in this study.

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Lock-on Characteristics of Wake Behind a Rotationally Oscillating Circular Cylinder (주기적으로 회전진동하는 원주 후류의 공진특성에 관한 연구)

  • Lee, Jung-Yeop;Lee, Sang-Joon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.8 s.239
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    • pp.895-902
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    • 2005
  • Lock-on characteristics of flow around a circular cylinder oscillating rotationally with a relatively high forcing frequency have been investigated experimentally. Dominant governing parameters are Reynolds number (Re), angular amplitude of oscillation (${\theta}_A$), and frequency ratio $F_R=f_f/f_n,\;where\;f_f$ is a forcing frequency and $f_n$ is a natural frequency of vortex shedding. Experiments were carried out under the conditions of $Re=4.14{\times}10^3,\;{\pi}/90{\leq}{\theta_A}{\leq}{\pi}/3,\;and\;F_R=1.0$. The effect of this active flow control technique on the lock-on flow characteristics of the cylinder wake was evaluated with wake velocity measurements and spectral analysis of hot-wire signals. The rotational oscillation modifies the flow structure of near wake significantly. The lock-on phenomenon always occurs at $F_R=1.0$, regardless of the angular amplitude ${\theta}_A$. In addition, when the angular amplitude is less than a certain value, the lock-on characteristics appear only at $F_R=1.0$,. The range of lock-on phenomena expands and vortex formation length is decreased, as the angular amplitude increases. The rotational oscillation create a small-scale vortex structure in the region just near the cylinder surface. At ${\theta}_A=60^{\circ}$, the drag coefficient was reduced about $43.7\%$ at maximum.

Crystal Structure and Tautomerism Study of the Mono-protonated Metformin Salt

  • Wei, Xiaodan;Fan, Yuhua;Bi, Caifeng;Yan, Xingchen;Zhang, Xia;Li, Xin
    • Bulletin of the Korean Chemical Society
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    • v.35 no.12
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    • pp.3495-3501
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    • 2014
  • A novel crystal, the mono-protonated metformin acetate (1), was obtained and characterized by elemental analysis, IR spectroscopy and X-ray crystallography. It was found that one of the imino group in the metformin cation was protonated along with the proton transfer from the secondary amino group to the other imino group. Its crystal structure was then compared with the previously reported diprotonated metformin oxalate (2). The difference between them is that the mono-protonated metformin cations can be linked by hydrogen bonding to form dimers while the diprotonated metformin cations cannot. Both of them are stabilized by intermolecular hydrogen bonds to assemble a 3-D supermolecular structure. The four potential tautomer of the mono-protonated metformin cation (tautomers 1a, 1b, 1c and 1d) were optimized and their single point energies were calculated by Density Functional Theory (DFT) B3LYP method based on the Polarized Continuum Model (PCM) in water, which shows that the most likely existed tautomer in human cells is the same in the crystal structure. Based on the optimized structure, their Wiberg bond orders, Natural Population Analysis (NPA) atomic charges, molecular electrostatic potential (MEP) maps were calculated to analyze their electronic structures, which were then compared with the corresponding values of the diprotonated metformin cation (cation 2) and the neutral metformin (compound 3). Finally, the possible tautomeric mechanism of the mono-protonated metformin cation was discussed based on the observed phenomena.

An Experimental Study on the Pump Operating Characteristics with Low Flow Operation (펌프의 저 유량 운전특성에 관한 실험적 연구)

  • 오광석;신필권;박종호;심우건;조두연
    • Journal of KSNVE
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    • v.9 no.1
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    • pp.85-96
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    • 1999
  • For ASME Code pumps in nuclear power plants, inservice test is required to assess the operational readiness in accordance with ASME code and related regulations. The objective of this study therefore, is to develop the technical background of the degradation of pump performances and conditions due to low flow rate operation. In addition. the detection techniques of pump operating conditions are to be developed to enhance the safety and economy of nuclear power plants. A test loop consisted of pump, motor. water tank, flow rate measurements and piping system with flow control devices was established for this study. Two typical pumps, 1-stage volute pump and 3-stage turbine pump, were selected and the test was performed upon two major point of views ; i.e., pump discharge pressure pulsations analysis and pump vibration spectrum analysis. From the test results, it is concluded that (1) the pump vibration affected by the natural frequency of operating pump is significant in the low frequency zone (around 1 Hz) : the vibration amplitude. especially. is an important factor during low flow rate operation. and shall be monitored to ensure that it is within the limit of ASME OM code Part 6, (2) the vibration frequency and pump discharge pressure are affected by vane pass frequency and running speed, (3) the wave phenomena due to the compressiblity of water is anticipated during low flow rate operation. and the pump system shall be designed to prevent it and. finally, (4) the technical background of the degradation of pump performances and conditions due to low flow rate operation is provided.

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A Study on the Combined Heat Transfer and Analysis Fire Induced Combustion Gas in a partially Open Enclosure (개구부가 있는 밀폐공간내 화재의 복합열전달 및 연소가스 분석에 관한 연구)

  • Park, Chan-Kuk;Chu, Byeong-Gil;Kim, Cheol
    • Fire Science and Engineering
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    • v.11 no.1
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    • pp.21-35
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    • 1997
  • The natural convection and combined heat transfer induced by fire in a rectangular enclosure is numerically studied. The model for this numerical analysis is partially opened right wall. The solution procedure includes the standard k-$\varepsilon$ model for turbulent flow and the discrete ordinates method (DOM) is used for the calculation of radiative heat transfer equation. In numerical study, SIMPLE algorithm is applied for fluid flow analysis, and the investigations of combustion gas induced by fire is performed by FAST model of HAZARD I program. In this study, numerical simulation on the combined naturnal convection and radiation is carried out in a partial enclosure filled with absorbed-emitted gray media, but is not considered scattering problem. The streamlines, isothermal lines, average radiation intensity and kinetic energy are compared the results of pure convection with those of the combined convection-radiation, the combined heat transfer. Comparing the results of pure convection with those of the combined convection-radiation, the combined heat transfer analysis shows the stronger circulation than those of the pure convection. Three different locations of heat source are considered to observe the effect of heat source location on the heat transfer phenomena. As the results, the circulation and the heat transfer in the left region from heating block are much more influenced than those in the right region. It is also founded that the radiation effect cannot be neglected in analyzing the building in fire. And as the results of combustion gas analysis from FAST model, it is found that O2 concentration is decreased according to time. While CO and CO2 concentration are rapidly increased in the beginning(about 100sec), but slowly decreased from that time on.

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A Study on Investigation for Effectiveness of Natural Minerals with Silica-Component as Admixture for Concrete

  • 김화중
    • Magazine of the Korea Concrete Institute
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    • v.6 no.3
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    • pp.201-214
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    • 1994
  • The fracture process zone in concrete is a region ahead of a traction-free crack, in which two major mechanisms, microcracking and bridging, play important roles. The toughness due to bridging is dominant compared to toughness induced by microcracking, so that the bridging is dominani: mechanism governing the fracture process of concrete. Fracture mechanics does work for concrete provided that the fracture process zone is being considered, so that the development of model for the fracture process zone is most important to describe fracture phenomena in concrete. In this paper the bridging zone, which is a part of extended rnacrocrack with stresses transmitted by aggregates in concrete, is modelled by a Dugdale-Barenblatt type model with linear tension-softening curve. Two finite element techniques are shown for the analysis of progressive cracking in concrete based on the discrete crack approach: one with crack element, the other without crack element. The advantage of the technique with crack element is that it dees not need to update the mesh topology to follow the progressive cracking. Numerical results by the techniques are demonstrated.

Postprocessing of A Speech Recognition using the Morphological Anlaysis Technique (형태소 분석 기법을 이용한 음성 인식 후처리)

  • 박미성;김미진;김계성;김성규;이문희;최재혁;이상조
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.36C no.4
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    • pp.65-77
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    • 1999
  • There are two problems which will be processed to graft a continuous speech recognition results into natural language processing technique. First, the speaking's unit isn't consistent with text's spacing unit. Second, when it is to be pronounced the phonological alternation phenomena occur inside morphemes or among morphemes. In this paper, we implement the postprocessing system of a continuous speech recognition that above all, solve two problems using the eo-jeol generator and syllable recoveror and morphologically analyze the generated results and then correct the failed results through the corrector. Our system experiments with two kinds of speech corpus, i.e., a primary school text book and editorial corpus. The successful percentage of the former is 93.72%, that of the latter is 92.26%. As results of experiment, we verified that our system is stable regardless the sorts of corpus.

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Rapid Cooling Performance Evaluation of a ZrCo bed for a Hydrogen Isotope Storage (수소동위원소 저장용 ZrCo용기의 급속 냉각 성능 평가)

  • Lee, Jungmin;Park, Jongchul;Koo, Daeseo;Chung, Dongyou;Yun, Sei-Hun;paek, Seungwoo;Chung, Hongsuk
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.2
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    • pp.128-135
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    • 2013
  • The nuclear fuel cycle plant is composed of various subsystems such as a fuel storage and delivery system (SDS), a tokamak exhaust processing system, a hydrogen isotope separation system, and a tritium plant analytical system. Korea is sharing in the construction of the International Thermonuclear Experimental Reactor (ITER) fuel cycle plant with the EU, Japan, and the US, and is responsible for the development and supply of the SDS. Hydrogen isotopes are the main fuel for nuclear fusion reactors. Metal hydrides offer a safe and convenient method for hydrogen isotope storage. The storage of hydrogen isotopes is carried out by absorption and desorption in a metal hydride bed. These reactions require heat removal and supply respectively. Accordingly, the rapid storage and delivery of hydrogen isotopes are enabled by a rapid cooling and heating of the metal hydride bed. In this study, we designed and manufactured a vertical-type hydrogen isotope storage bed, which is used to enhance the cooling performance. We present the experimental details of the cooling performances of the bed using various cooling parameters. We also present the modeling results to estimate the heat transport phenomena. We compared the cooling performance of the bed by testing different cooling modes, such as an isolation mode, a natural convection mode, and an outer jacket helium circulation mode. We found that helium circulation mode is the most effective which was confirmed in our model calculations. Thus we can expect a more efficient bed design by employing a forced helium circulation method for new beds.

Childhood Hypersomnia and Sleep Apnea Syndrome (소아수면과다증과 수면무호흡)

  • Sohn, Chang-Ho;Jeong, Do-Un
    • Sleep Medicine and Psychophysiology
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    • v.3 no.2
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    • pp.65-76
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    • 1996
  • Natural sleep pattern and its physiology in childhood are much different from those in adulthood. Several aspects of clinical evaluation for sleepiness in childhood are more difficult than in adulthood. These difficulties are due to several factors. First, excessive sleepiness in childhood do not always develop functional impairments. Second, objective test such as MSLT may not be reliable since it is hard to be certain that the child understand instructions. Third, sleepiness in children is often obscured by irritability. paradoxical hyperactivity, or behavioral disturbances. Anseguently, careful clinical evaluation is needed for the sleepy children. Usual causes of sleepiness in children are the disorders that induce insufficient sleep such as sleep apnea syndrome, schedule disorder, underlying medical and psychiatric disorder, and so forth. After excluding such factors, we can diagnose the hypersomnic disorders such as narcolepsy, Kleine-Levin syndrome, and idiopathic central nervous system hypersomnia. Among the variety of those causes of sleepiness, I reviewed the clinical difference of narcolepsy and obstructive sleep apnea syndrome in childhood compared with in adulthood. Recognition of the childhood narcolepsy is difficult because even severely sleepy children often do not develop pathognomic cataplexy and associated REM phenomena until much later. Since childhood narcolepsy give srise to many psychological, academical problem. Practicers should be concerned about these aspects. Childhood obstructive sleep apnea syndrome is different from adult obstructive sleep apnea syndrome too. Several aspects such as pathophysiology. clinical feature, diagnostic criteria, complication, management, and prognosis differ from those in the adult syndrome. An important feature of childhood obstructive sleep apnea syndrome is the variety of severe complications such as behavioral disorders, cognitive impairment, cardiovascular symptoms, developmental delay, and ever death. Fortunately, surgical interventions like adenotosillectomy or UPPP are more effective for Childhood OSA than adult form. CPAP is a "safe, effective, and well-tolerated" treatment modality too. So if early detection and proper management of childhood OSA were done, the severe complication would be prevented or ever cured.

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Introduction to the Technology, Applications, Products, Markets, R&D, and Perspectives of Nanofoods in the Food Industry

  • Kim, Dong-Myong;Lee, Gee-Dong
    • Preventive Nutrition and Food Science
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    • v.11 no.4
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    • pp.348-357
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    • 2006
  • Nano is a unit that designates a billionth; accordingly nanotechnology could be described as the study and applications of the unique characteristics and phenomena of nanometer size materials. Applications of nanotechnology fall into two categories (one is top-down and the other is bottom-up). Currently, most products are the results of the top-down approach. Nanofoods have distinct functional characteristics stemming from the size, mass, chemical combinations, electrolytic features, magnetic properties of food sources at the nano level and which can be applied for safe absorption and delivery into the body. The greatest advantage of nanofood is that it permits the efficient use of small quantities of nutritional elements by increasing digestive absorption ability and by delivering natural elements without any change in their original characteristics. On the other hand, there are still unsolved problems, such as questions about safety and introduction of harmful material. The demand for new commercial food products is increasing, and commercial food producers are gradually combining nanotechnology and traditional food preparation methods. Nanofoods will improve our eating habits remarkably in the future. Tomorrow we will design nanofoods by shaping molecules and atoms. It will have a big impact on the food and food-processing industries. The future belongs to new products and new processes with the goals of customizing and personalizing consumer products. Nanotechnology is expected to be applied to not only foods themselves, but also to food packaging, production, safety, processing and storage. Also, it is believed that nanotechnology will be applied tracking finished products back to production facilities and even to specific processing equipment in those facilities. The aim of this study is the introduction of technology, applications, products, markets, R&D, and perspectives of nanofoods in the food industry.