• Title/Summary/Keyword: Force Reflection

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Generation and Growth of Long Ocean Waves along the West Coast of Korea in March 2007 (2007년 3월 한국 서해안에 발생한 해양장파의 형성과 성장과정)

  • Choi, Byoung-Ju;Park, Yong-Woo;Kwon, Kyung-Man
    • Ocean and Polar Research
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    • v.30 no.4
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    • pp.453-466
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    • 2008
  • In order to examine the generation mechanism of long ocean waves along the west coast of Korea and to understand the amplification process of the long ocean waves, sea level, atmospheric pressure and wind data observed every minute from 2007 March 29 to 2007 April 1 were analyzed and onedimensional numerical ocean model experiments were performed. An atmospheric pressure jump propagated southeastward from Backryungdo to Yeonggwang along the west coast of Korea with speed of $13{\sim}27\;m/s$ between 2007 March 30 23:00 and 2007 April 1 1:30. Average magnitude of pressure jump was 4.2 hPa. As a moving atmospheric jump propagated from north to south along the coast, long ocean waves were generated and the sea level abnormally rose or fell at Anheung, Kunsan, Wido and Yeonggwang. Average amplitude of sea level rise (or fall) was about 113.6 cm. In a one-dimensional numerical ocean model, nonlinear shallow water equations were numerically integrated and a moving atmospheric pressure jump with traveling speed of 24 m/s was used as an external force. While the atmospheric pressure jump travels over 60 m depth ocean, a long ocean wave is generated. Because the propagation speed of the atmospheric jump is almost equal to that of the long ocean wave, Proudman resonance occurs and the long ocean wave amplifies. As the atmospheric pressure jump moves into the coastal area shallower than 60 m, the speed of the long ocean wave decreases and Proudman resonance effect decreases. However, the amplitude of the long ocean wave increases and wave length becomes shorter because of shoaling effect. When the long ocean wave hits the land boundary, amplitude of the long ocean wave drastically amplifies due to reflection. Data analysis and numerical experiments suggest that the southeastward propagation of an atmospheric pressure jump over the shallow ocean, which is a necessary condition for Proudaman resonance, generated the long ocean waves along the west coast of Korea on 2007 March 31 and the ocean waves amplified due to shoaling effect in the coastal area and reflection at the shore.

Ch'oe Han-gi's Reflection on Relationalities in Existence (최한기의 존재론적 관계성 성찰)

  • Rhee, Myung-Su
    • The Journal of Korean Philosophical History
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    • no.59
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    • pp.395-423
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    • 2018
  • Since the middle of the 19th century, East Asia, especially Korea, was oppressed externally by the imperialism of Japan and others while internally long-lasting political convention like in-law government was driving the country into troubles at home and abroad. Witnessing such a situation and building up scholarly capability through reading over nearly all spheres, a Confucian philosopher, Ch'oe Han-gi (崔漢綺, 1803-1877), philosophized about the clue to the solution of such a choking phenomenon. Ch'oe believed that there was movement, ki (matter, material force, energy) of revolving transformation inherent in all things, people, or objects. Grasping even the principle and order of existence inherent in things from the viewpoint of ki, he tried to change the traditional theory on the law of existence of things that there existed an ontological reason lacking in motility, which was more dominant than anything existing in the universe and which ruled over the world. From this, he elucidated that the Way, an identity that rules over all affairs and things, was not simply one but diverse. This means, on one hand, that he tentatively accepted the relativity of things. On the other hand, he also taught us "oneness in all things" in which all including human beings exist in close connection to each other transcending the relativity or "agreement" in which they exist in harmony as one and "unity" in which they are united into one.

Wave Absorbing Characteristics of a Horizontal Submerged Punching Plate (수평형 타공판의 소파특성)

  • 조일형
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.14 no.4
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    • pp.265-273
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    • 2002
  • In this paper, wave absorbing characteristics of a horizontal submerged punching plate are investigated throughout the calculation and the experiment. The punching plate with the array of circular holes can force the flow to separate and to form eddies of high vorticity and cause significant energy loss. As an analytic tool, the linear water wave theory and the eigenfunction expansion method is applied. Darcy's law that the normal velocity of the fluid passing through the punching plate is linearly proportional to the pressure difference between two sides of the punching plate is assumed. The proportional constant called the porous coefficient is deeply dependent to the porosity. To obtain the relationship between the porosity and the porous coefficient the systematic model test for the punching plates with 6 different porosities is conducted at 2-dimensional wave tank. It is found that the porous coefficient is linearly proportional to the porosity(b=57.63P-0.9717). It is also noted that the optimal porosity value is near P=0.1 and the optimal range of submergence depth is $d/h\\leq0.2$ within entire frequency range.

Spirituality: Concept Analysis (영성(Spirituality) 개념 분석)

  • O, Bok-Ja;Gang, Gyeong-A
    • Journal of Korean Academy of Nursing
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    • v.30 no.5
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    • pp.1145-1155
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    • 2000
  • The purpose of this study is to explore the concept spirituality and to gain understanding of nursing intervention that may improve spiritual well-being. The concept analysis framework developed by Walker and Avant (1995) was used to clarify the concept. In the study, 'Harmonious interconnectedness', 'Transcendence', 'Integrative Energy' and 'Purpose and Meaning in Life' emerged as the critical attributes of spirituality. The first attribute, 'harmonious Inter- connectedness', has three categories including intrapersonal, (self), interpersonal (others/ nature) and transpersonal (the Supreme Being). The second attribute, 'Transcendence', is defined as the ability to extend one's own self beyond the limits of usual experiences and to achieve new perspectives. This attribute is demonstrated by 'coping with situations', to 'self-healing', and 'transformation'. The third attribute of spirituality is 'Integrative Energy', which integrates all dimensions and acts as a creative and dynamic force that keeps a person growing and changing. 'Integrative Energy is also defined as an inner resource that gives a sense of empowerment. Therefore the highly spiritual person demonstrate 'inner peace', 'growing', 'inner strength,' and 'well-being'. The fourth attribute 'Purpose and Meaning in Life' represents a sense of connectedness with one's inner values and with a greater purpose in life. It is demonstrated by 'hope' and 'a powerful life'. In this study, the antecedents of the spirituality represented as 'spirit' and its potential enablers were 'Introspection/reflection', 'Interconnectedness with all living things', and an 'Awareness of a Higher-Power'. The consequences of this concept may be described as 'physical, psychosocial, and spiritual well-being'. Empirical referents of this are 'purposeful life' 'self-worth' 'hope' 'love' 'service' 'forgiveness' 'trust/belief' 'inner peace' 'self-actualization' 'religious practices' 'transformation' 'inner strength' and 'coping'. In conclusion, spirituality can be defined based on these critical attributes. Spirituality is a dynamic, integrative energy based on a feeling of harmonious interconnection with self, others and a higher power. Through it, one is enabled to transcend and to live with meaning and purpose in life.

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The combined use of computer-guided, minimally invasive, flapless corticotomy and clear aligners as a novel approach to moderate crowding: A case report

  • Cassetta, Michele;Altieri, Federica;Pandolfi, Stefano;Giansanti, Matteo
    • The korean journal of orthodontics
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    • v.47 no.2
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    • pp.130-141
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    • 2017
  • The aim of this case report was to describe an innovative orthodontic treatment method that combined surgical and orthodontic techniques. The novel method was used to achieve a positive result in a case of moderate crowding by employing a computer-guided piezocision procedure followed by the use of clear aligners. A 23-year-old woman had a malocclusion with moderate crowding. Her periodontal indices, oral health-related quality of life (OHRQoL), and treatment time were evaluated. The treatment included interproximal corticotomy cuts extending through the entire thickness of the cortical layer, without a full-thickness flap reflection. This was achieved with a three-dimensionally printed surgical guide using computer-aided design and computer-aided manufacturing. Orthodontic force was applied to the teeth immediately after surgery by using clear appliances for better control of tooth movement. The total treatment time was 8 months. The periodontal indices improved after crowding correction, but the oral health impact profile showed a slight deterioration of OHRQoL during the 3 days following surgery. At the 2-year retention follow-up, the stability of treatment was excellent. The reduction in surgical time and patient discomfort, increased periodontal safety and patient acceptability, and accurate control of orthodontic movement without the risk of losing anchorage may encourage the use of this combined technique in appropriate cases.

Low-Temperature Si and SiGe Epitaxial Growth by Ultrahigh Vacuum Electron Cyclotron Resonance Chemical Vapor Deposition (UHV-ECRCVD)

  • Hwang, Ki-Hyun;Joo, Sung-Jae;Park, Jin-Won;Euijoon Yoon;Hwang, Seok-Hee;Whang, Ki-Woong;Park, Young-June
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1996.06a
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    • pp.422-448
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    • 1996
  • Low-temperature epitaxial growth of Si and SiGe layers of Si is one of the important processes for the fabrication of the high-speed Si-based heterostructure devices such as heterojunction bipolar transistors. Low-temperature growth ensures the abrupt compositional and doping concentration profiles for future novel devices. Especially in SiGe epitaxy, low-temperature growth is a prerequisite for two-dimensional growth mode for the growth of thin, uniform layers. UHV-ECRCVD is a new growth technique for Si and SiGe epilayers and it is possible to grow epilayers at even lower temperatures than conventional CVD's. SiH and GeH and dopant gases are dissociated by an ECR plasma in an ultrahigh vacuum growth chamber. In situ hydrogen plasma cleaning of the Si native oxide before the epitaxial growth is successfully developed in UHV-ECRCVD. Structural quality of the epilayers are examined by reflection high energy electron diffraction, transmission electron microscopy, Nomarski microscope and atomic force microscope. Device-quality Si and SiGe epilayers are successfully grown at temperatures lower than 600℃ after proper optimization of process parameters such as temperature, total pressure, partial pressures of input gases, plasma power, and substrate dc bias. Dopant incorporation and activation for B in Si and SiGe are studied by secondary ion mass spectrometry and spreading resistance profilometry. Silicon p-n homojunction diodes are fabricated from in situ doped Si layers. I-V characteristics of the diodes shows that the ideality factor is 1.2, implying that the low-temperature silicon epilayers grown by UHV-ECRCVD is truly of device-quality.

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Immobilization of Lactobionic Acid on Polyurethane Films and Their Interaction with Hepatocytes

  • Meng Wan;Jung Kyung-Hye;Kang Inn-Kyu;Kwon Oh Hyeong;Akaike Toshihiro
    • Macromolecular Research
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    • v.13 no.3
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    • pp.257-264
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    • 2005
  • Polyurethanes containing z-Iysine segments in the main chain (PULL) were synthesized from 4,4'-diphe-nylmethyl diisocyanate, poly(tetramethylene glycol), and z-Iysine oligomer as a chain extender. The PULL film was treated first with a $10\%$ HBr-acetic acid solution and subsequently with a saturated sodium bicarbonate aqueous solution to produce a primary amine group on the surface (PULL-N). Lactobionic acid (LA)-immobilized PULL (PULL-L) was prepared by the coupling reaction of the PULL surface amine groups and the LA carboxylic acid groups. The surface-modified PULLs were then characterized by attenuated total reflection-Fourier transform infra-red spectroscopy, electron spectroscopy for chemical analysis, atomic force microscopy, and contact angle goniometry. In the hepatocytes adhesion experiment, the cells poorly adhered to the PULL surface, although they adhered moderately well to the PULL-N surface. On the other hand, the cells adhered well to the PULL-L surface, suggesting the good affinity of the surface $\beta$-galactose moieties for hepatocytes. When hepatocytes were cultured in the presence of epidermal growth factor for 48 h, the cells rapidly aggregated on the PULL-L surface, whereas they aggregated only slowly on the other surfaces. The PULL prepared in this study has the potential to be used as a coating material for the enhancement of hepatocyte adhesion.

Substrate tempperature dependence of crystalline Y2O3 films grown by Ionized Cluster Beam Deposition

  • Cho, M.H.;Whangbo, S.W.;Seo, J.G.;Choi, S.C.;Cho, S.J.;Whang, C.N.
    • Proceedings of the Korean Vacuum Society Conference
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    • 1998.02a
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    • pp.87-89
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    • 1998
  • The Y2O3 films on Si(111) was grown by ionized cluster beam depposition (ICBD) in ultrahigh-vacuum (UHV). The acceleration voltage and oxygen ppartial ppressure were fixed at 5 kV and 2$\times$10-5 Torr resppectively. The substrate tempperature was varied from 10$0^{\circ}C$ to $600^{\circ}C$ in order to find the deppendence of crystallinity of Y2O3 films on the substrate tempperature. The crystallinity of the films with the substrate tempperature studied using x-ray diffraction (XRD) and Rutherford backscattering sppectroscoppy (RES). Surface crystallinity and surface morpphology of the films were also investigated using the reflection high-energy electron diffraction (RHEED) and atomic force microscoppe (AFM) resppectively. The films grown at the substrate tempperature below 50$0^{\circ}C$showed the ppoly-crystalline structure of oxygen deficiency. On the contrary the single-crystalline structure was obtained at the substrate tempperature over 50$0^{\circ}C$ and the stochimetry was gradually matched as increasing the substrate tempperature. The surface morpphology showed the increase of the surface roughness as the substrate tempperature was increased upp to 50$0^{\circ}C$ The crystallinity of the film was not good and the minimum channeling yield $\chi$min was measured at 0.91 The stochiometric and high crystallinine film (surface $\chi$min=0.25) was obtained as the substrate tempperature increased upp to 60 $0^{\circ}C$ which indicate the tempperature was sufficient to migrate the depposited atom.

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Improvement of resistance performance of the 4.99 ton class fishing boat (4.99톤 어선의 저항성능 개선)

  • JEONG, Seong-Jae;AN, Heui-Chun;KIM, In-Ok;PARK, Chang-Doo
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.53 no.4
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    • pp.446-455
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    • 2017
  • The improvement of resistance performance for the 4.99 ton class fishing boats was shown. The 4.99 ton fishing boats are the most commonly used one in the Korean coastal region. The evaluation of resistance performance was estimated by the Computational Fluid Dynamics (CFD) analysis. The CFD simulation was performed by the validation for various types of bow shapes on the hull. The optimized hull form from the simulation was selected and showed the best resistance performance. This hull type was tested on the towing tank in the National Institute of Fisheries Science (NIFS). The effective horsepower (EHP) was estimated by the resistance test on the towing tank with the bare hull condition. The drag force on the three service speed conditions was obtained for the resistance analysis to power prediction. The measured drag forces are compared with the results from the CFD simulation with one another. As results of the model tests, it was confirmed that the shape of the bow is an important factor in the resistance performance. The effective horsepower decreased about 30% in comparison with the conventional hull form. Also, the resistance performance improved the reduction of required horsepower, which especially contributed to the energy-saving for the fisheries industry. In the CFD analysis, the resistance performance improved slightly. In this case, the ratio of the residual resistance ($C_R$) in the total resistance ($C_T$) was high. Therefore, the CFD analysis was not enough to satisfy with reflection for the free surface and wave form in the CFD procedure. Both model test and CFD calculation in this study can be applied to the initial design process for the coastal fishing vessel.

Fabrication of Size-Controlled Hole Array by Surface-Catalyzed Chemical Deposition (표면 촉매 화학 반응을 이용한 크기 조절이 가능한 홀 어레이 제작)

  • Park, Hyung Ju;Park, Jeong Won;Lee, Dae-Sik;Pyo, Hyeon-Bong
    • Journal of Sensor Science and Technology
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    • v.27 no.1
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    • pp.55-58
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    • 2018
  • Low-cost and large-scale fabrication method of nanohole array, which comprises nanoscale voids separated by a few tens to a few hundreds of nanometers, has opened up new possibilities in biomolecular sensing as well as novel frontier optical devices. One of the key aspects of the nanohole array research is how to control the hole size following each specific needs of the hole structure. Here, we report the extensive study on the fine control of the hole size within the range of 500-2500 nm via surface-catalyzed chemical deposition. The initial hole structures were prepared via conventional photo-lithography, and the hole size was decreased to a designed value through the surface-catalyzed chemical reduction of the gold ion on the predefined hole surfaces, by simple dipping of the hole array device into the aqueous solution of gold chloride and hydroxylamine. The final hole size was controlled by adjusting reaction time, and the optimal experimental condition was obtained by doing a series of characterization experiments. The characterization of size-controlled hole array was systematically examined on the image results of optical microscopy, field emission scanning electron microscopy(FESEM), atomic-force microscopy(AFM), and total internal reflection microscopy.