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Numerical Upwelling Experiment for Optimum Arrangement of Artificial Seamount (용승을 고려한 인공해중산 최적배치 수치실험)

  • Kim, Seong-Hyeon;Kim, Dong-Sun
    • Journal of Environmental Science International
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    • v.20 no.8
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    • pp.997-1009
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    • 2011
  • In order to estimate volume transport by upwelling for single artificial seamount, same shape and size of artificial seamount already deployed was applied to numerical experiment. The result showed that strong upwelling appeared at front while took place downwelling at rear. The strongest upwelling existed at the top of the artificial seamount. Volume transport by upwelling was computed as 785 m3/s. Column arrangement was applied to two artificial seamount in three cases; case 1) no clearance, case 2) sixty-five meters of clearance as half of artificial seamount's length, and case 3) hundred-thirty meters of clearance as an artificial seamount's length. All cases of column arrangements showed more upwelling volume transport than that of single seamount. Particularly, the case of no clearance calculated as 106% and appeared the most upwelling effect comparing to two other cases. Row arrangement was also applied to two artificial seamount in three cases; case 4) no clearance, case 5) forty meters of clearance as an artificial seamount's width, and case 6) eighty meters of clearance as twice of artificial seamount's width. Upwelling volume transport in case 4 increased 48% than the case of single seamount. Other two cases of 5 and 6 were estimated as 97% increased and more effective than case 4. According to the case experiments, column arrangements show more upwelling volume transport than that of row arrangements. In cases of column arrangements, with decreasing clearance between two seamount, the effect increases while showing maximum value at clearance zero. In cases of row arrangements, on the contrary, with decreasing clearance between two seamount, the effect decreases while showing minimum value at clearance zero. Since simple barotropic condition was considered for this study, further study is necessary by considering baroclinic condition to get close to reality. In conclusion, in deploying artificial seamount, optimal arrangement should be well designed to enhance primary and secondary productivity and to increase the diversity of species as well as reducing time and space.

A Study on the Wedge shape Detector of Very High Resolution Positron Emission computer Tomography (초고해상도 양전자 방출 CT의 쐐기형 검출기에 관한 연구)

  • 이행세;이태원
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.22 no.2
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    • pp.44-54
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    • 1985
  • The high resolution of positron emission tomography, in particular, requires the use of detector crystals of narrow width but still with sufficiently high detection efficiency. If the crystal width is reduced to several millimeters, degradation of detection efficiency and leakage coefficient becomes significant, particularly in case of obliquely incident photons. Alleviation of such a problem can be made possible by modification of the detector shape from the conventional rectangular type to a wed농e type. The Proposed wedge shape makes the absorption length longer for obliquely incident photons, thus increasing the detection efficiency and suppressing leakage coefficient. For the BGO detectors of 4-8mm width, the computer simulation result of the system using wedge detectors reveals resolution improvement to the system using conventional detectors. For the system composed of 200 BGO detectors of 8mm width with 2 point sampling motion, the simulation resolution system using conventional detectors. For the very high resolution system of 3-7mm FWHM, the characteristics of the detector shape and size is studied by computer simulation.

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A Study on the Characteristics of Computerized Tomographic X-Ray Film (CT X선용(線用)필름의 특성(特性) 연구(硏究))

  • Lee, Man-Koo;Kang, Se-Sik;Lee, Jae-Wan
    • Journal of radiological science and technology
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    • v.10 no.1
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    • pp.49-53
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    • 1987
  • This thesis compared and analyzed the characteristics, centered on a characteristic curve, about X-ray computerized tomographic film generally used in Korea recently. The results were as follows: 1. Maximum gradient (gamma) was film A-2.19, film B-2.00, film C-1.92. 2. Latitude was confined within the limits of density 0.6-2.0 in all. 3. When we changed window center from 0 to 40, the difference of density, which was in 1.0, was film A-0.12, film B-0.16, fil m C-0.14. 4. When we changed window width from 0 to 500, the difference of density, which was in 1.0, was film A-0.06, film B-0.08, film C-0.05. 5. In the case of window width 50 and window center 20, latitude was 0.5-2.0, 0.5-2.2, 0.5-1.9 and gamma value was 1.74, 1.82, 1.72 respectively, 6. In the case of window width 80 and window center 30, latitude was 0.6-2.2, 0.6-2.3, 0.8-2.2 and gamma value was 2.0, 2.13, 1.95 respectively.

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Effect of Coating Layer Hardness on Frictional Characteristics of Diesel Engine Piston Ring (디젤엔진 피스톤 링 코팅 층의 경도에 따른 마찰특성)

  • Jang, J.H.;Joo, B.D.;Lee, H.J.;Kim, E.H.;Moon, Y.H.
    • Transactions of Materials Processing
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    • v.18 no.6
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    • pp.465-470
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    • 2009
  • The frictional behaviors of Cermets/Cr-Ceramics and Cu-Al coatings of piston ring were investigated. Friction tests were carried out by pin-on-disk test and materials properties of coating layer were analyzed by nano indentation tester. The effect of surface roughness of cylinder liner on the friction coefficient was analyzed. This study provided tribological data of hard and soft piston ring coatings against cylinder liner. The surface roughness does exert an influence on the average friction coefficient, with smoother surfaces generally yielding lower friction coefficients. In case of hard-coating, the scratch depth, width and pile-up height had close relationship with hardness. So the scratch width, depth and pile-up height increases with decreasing friction coefficient. But in case of soft-coating, the friction coefficients are strongly dependent on the morphological characteristics such as, scratch depth, width, pile-up height and elastic modulus.

Clinical evaluation of a collagen matrix to enhance the width of keratinized gingiva around dental implants

  • Lee, Kang-Ho;Kim, Byung-Ock;Jang, Hyun-Seon
    • Journal of Periodontal and Implant Science
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    • v.40 no.2
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    • pp.96-101
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    • 2010
  • Purpose: The purpose of this study was to evaluate the effect of collagen matrix with apically positioned flap (APF) on the width of keratinized gingiva, comparing to the results of APF only and APF combined with free gingival graft (FGG) at the second implant surgery. Methods: Nine patients were selected from those who had received treatments at the Department of Periodontics, Chosun University Dental Hospital, Gwangju, Korea. We performed APF, APF combined with FGG, and APF combined with collagen matrix coverage respectively. Clinical evaluation of keratinized gingival was performed by measuring the distance from the gingival crest to the mucogingival junction at the mid-buccal point, using a periodontal probe before and after the surgery. Results: The ratio of an increase was 0.3, 0.6, and 0.6 for the three subjects in the APF cases, 3, 5, and 7 for the three in the APF combined with FGG case, and 1.5, 0.5, and 3 for the three in the APF combined with collagen matrix coverage case. Conclusions: This study suggests that the collagen matrix when used as a soft tissue substitute with the aim of increasing the width of keratinized tissue or mucosa, was as effective and predictable as the FGG.

The First Case of Successful Bark Implantation of a 250-year-old Zelkova Tree Heavily Damaged by Artificial Girdling

  • Ryu, Seong Ho;Kim, Gyoung Hee;Koh, Young Jin
    • Research in Plant Disease
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    • v.24 no.3
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    • pp.237-241
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    • 2018
  • A circular bark with a 30 cm width was artificially removed from the trunk of a 250-year-old zelkova tree (Zelkova serrata) heavily damaged by artificial girdling in Sunchang, Jeonbuk Province in March of 2005. The debarked area was cleaned approximately 10 days after artificial girdling and bark margins with 2 cm width above and below the girdled portion were cut off to promote wound callus formation. Nine pieces of fresh bark (width 8 cm, length 35 cm, thickness 0.5 cm) were then prepared from branches of neighbor zelkova trees broken by heavy snowfalls and pasted onto the girdled portion of the tree, after which a Vaseline dressing was applied to water-proof the area and rubber bars were used to hold the implants to the trunk. Two pieces of the implanted fresh barks were successfully grafted onto the girdled area and the damaged tree has been vigorously growing over 13 years. To our knowledge, this is the first case of successful bark implantation to cure a 250-year-old zelkova tree heavily damaged by artificial girdling. This bark implantation technique will be utilized for the conversation and management of heavily damaged big and old trees in the future.

Orthodontic treatment in a patient with Moebius syndrome: A case report

  • Lee, Sanghee;Moon, Cheol-Hyun
    • The korean journal of orthodontics
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    • v.52 no.6
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    • pp.451-460
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    • 2022
  • Moebius syndrome (MBS) is a congenital neurologic disorder that causes cranio-facial abnormalities. It involves paralysis of the VI and VII cranial nerves and causes bilateral or unilateral facial paralysis, eye movement disorder, and deformation of the upper and lower limbs. The orofacial dysfunctions include microstomia, micrognathia, hypotonic mimetic and lip muscles, dental enamel hypoplasia, tongue deformity, open bite or deep overbite, maxillary hypoplasia, high arched palate, mandibular hyperplasia or features indicating mandibular hypoplasia. This case report presents a 7-year-old male patient who was diagnosed with MBS at the age 2 years. The patient displayed typical clinical symptoms and was diagnosed with Class II malocclusion with a large overjet/overbite, tongue deformity and motion limitation, and lip closure incompetency. Treatment was initiated using a removable appliance for left scissor bite correction. After permanent tooth eruption, fixed appliance treatment was performed for correction of the arch width discrepancy and deep overbite. A self-ligation system and wide-width arch form wire were used during the treatment to expand the arch width. After 30 months of phase II treatment, the alignment of the dental arch and stable molar occlusion was achieved. Function and occlusion remained stable with a Class I canine and molar relationship, and a normal overjet/overbite was maintained after 9.4 years of retainer use. In MBS patients, it is important to achieve an accurate early diagnosis, and implement a multidisciplinary treatment approach and long-term retention and follow-up.

Ultimate strength of simply supported plate with opening under uniaxial compression

  • Yu, Chang-Li;Lee, Joo-Sung
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.4 no.4
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    • pp.423-436
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    • 2012
  • Unstiffened plates are integral part of all kinds of structures such as ship and offshore oil platforms. Openings are unavoidable and absolutely reduce the ultimate strength of structures. In this study, the finite element analysis package, ABAQUS, is used to analyze the behavior of unstiffened plate with rectangular opening. The rectangular opening form is divided into two cases. In case1, opening depth is constant, but opening width is varied. Meanwhile, in case2 opening width is fixed and opening depth is varied. Besides, for the two different form opening, the effect of plate slenderness parameter (${\beta}$), opening area ratio (AR) and opening position ratio (PR) on the ultimate strength of plate with opening under axial compression are presented. It has been found that the ultimate strength of plate ofcase1is much more sensitive to the plate slenderness parameter (${\beta}$) and opening area ratio (AR) than that of case2. However, for case1, opening position (PR) almost has no effect on the ultimate strength, whereas, regardingcase2, the influence of opening position (PR) depends on the plate slenderness parameter (${\beta}$). Based on nonlinear regression analysis, three design formulae are not only developed but also approved reasonably for the practical engineering design.

A design of multi-width HTS magnets considering both wire consumption and field homogeneity

  • Yang, Hongmin;Ahn, Minchul
    • Progress in Superconductivity and Cryogenics
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    • v.23 no.2
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    • pp.24-27
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    • 2021
  • This paper presents a design methodology of high-temperature superconducting (HTS) magnets. The magnet consists of several double pancake coils with a variety of wire width. This technique, named Multi-Width, is well known to make efficient use of the superconducting wire. It is common for design of high-temperature superconducting magnets to not only reduce wire consumption used, but also consider the homogeneity of the magnetic field. In this paper, we study a design method that efficiently reduces wire usage while considering magnetic field homogeneity. The design is carried out by calculating the critical current and the critical magnetic field according to the configuration of arranging the thickness of the wire to determine the number of windings. The width of wire comprising the magnet was set to 4 - 12 mm, and the number of double pancake coils was set to an even number to consist of top-down symmetry. To verify the validity of the design, we compared the progress of the design code with a complete enumeration survey. As a case study, we designed a magnet that generates a central magnetic field of 3 T or more in a 240 mm bore in diameter. Optimality can be evaluated by weighing wire consumption and field homogeneity according to the magnet's use or user preference.

Visual Evaluation of Design Variations in Power Shoulder Jacket (파워 숄더 재킷의 디자인변화에 따른 시각적 평가)

  • Kim, Jeong-Mee;Lee, Jung-Soon
    • Journal of Fashion Business
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    • v.15 no.1
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    • pp.80-91
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    • 2011
  • The purpose of this study is to evaluate the differences of visual effects and visual images by variations in shoulder angle and shoulder width of power shoulder jacket. The stimuli are 5 samples: One control group, 2 variations of the angle of shoulder line and 2 variations of the width of shoulder line. The data has been obtained from 87 fashion design majors. The data has been analyzed by Factor Analysis, Anova, Scheffe's Test and the Correlation Analysis. The results of the study are as follows: The visual images by the angle and the width of shoulder line of power shoulder jacket are composed of 4 factors : attention, stiffness and softness, masculinity, and trendiness. Among these factors, attention factor is estimated by the most important factor. The visual effects by the angle and the width of shoulder line of power shoulder jacket are composed of 3 factors : whole silhouette, neck and arm figure, upper body figure. In these factors, the whole silhouette is estimated by the most important factor. The power shoulder jacket with extreme changes in shoulder angle has double images: it looks trendy and classy but also gives an awkward image. In case of changes in shoulder width, the visual evaluation shows big differences with the degree of expansion. The visual evaluation with variation in angle has stronger image and effect than that in width. The power shoulder jacket trend itself is also evaluated that variation in angle reflects the trend better than that in width.