• Title/Summary/Keyword: structural alterations

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A Study on the Aerodynamic Characteristic of Gunfire Damaged Airfoil (화포에 의해 손상된 날개의 공력특성에 관한 연구)

  • Lee, Ki-Young;Chung, Hyoung-Seog;Kim, Si-Tae
    • Journal of the Korea Institute of Military Science and Technology
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    • v.11 no.2
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    • pp.144-151
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    • 2008
  • An experimental study has been conducted to investigate the effects of circular damage hole on the characteristics of airfoil performance. The damage on a wing created from a hit by anti-air artillery was modeled as a circular hole. Force balance measurements and static pressure measurements on the wing surface were carried out for the cases of having damage holes of 10% chord size at quarter chord and/or half chord positions. All experiments were conducted at Reynolds number of $2.85\times10^5$ based on the chord length. The surface pressure data show big pressure alterations near the circular damage holes. This abnormal surface pressure distribution produces shear stress that could lead to the acceleration of the structural degradation of the wing around the circular damage hole. However, in spite of the existence of circular damage holes, the measured force data indicated the only a slight decrease in lift accompanied by increase in drag compared to the results of undamaged one. The influence of damage hole on the aerodynamic performance was increased as the location of damage moved to the leading edge. The effect on the control force was insignificant when the damaged size was not large.

CEPHALOMETRIC STUDY IN PATIENTS WITH FUNCTIONAL ALTERATIONS OF THE TEMPOROMANDIBULAR JOINT (측두 하악관절의 기능적 변화가 있는 환자의 측모두부방사선 계측학적 연구)

  • Kwon, Byung-In;Baik, Hyoung-Seon
    • The korean journal of orthodontics
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    • v.22 no.3 s.38
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    • pp.703-713
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    • 1992
  • Researches in pathologic entities and syndromes that describe temporomandibular joint (TMJ) or TMJ-related pain and dysfunction, have been hampered by confusion and conflict over the pathogenesis of myofascial and joint pain, the character and causes of joint noises, and the lack of scientific methods. Investigators have more recently correlated clinical diagnosis and arthrographic and surgical findings to demonstrate 'internal derangements' of the TMJ. It is thought that the structural and functional changes characteristic of internal derangements constitute the principal pathologic entity of the TMJ. Cephalometric data from a group of 34 subjects with documented functional changes in the TMJ were compared with those of a group of 35 subjects from a control sample. The results were as follows: 1. Comparison of a group which shows Class I relationship, there was a tendency to show clock-wise rotation of mandible and linguoversion of upper and lower anterior teeth in the experimental sample. 2. Excluding the vertical relationship, there was a tendency to show low values of the lingual surface slope of the upper central incisor and high values of the interincisor angle in the experimental sample.

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A simulation study on the figure of merit optimization of a 1200V 4H-SiC DMOSFET (1200V급 4H-SiC DMOSFET 성능지수 최적화 설계 시뮬레이션)

  • Choi, Chang-Yong;Kang, Min-Suk;Bang, Wook;Kim, Sang-Chul;Kim, Nam-Kyun;Koo, Sang-Mo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.63-63
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    • 2009
  • In this work, we demonstrate 800V 4H-SiC power DMOSFETs with several structural alterations to observe static DC characteristics, such as a threshold voltage ($V_{TH}$) and a figure of merit ($V_B^2/R_{SP,ON}$). To optimize the static DC characteristics, we consider four design parameters; (a) the doping concentration ($N_{CSL}$) of current spreading layer (CSL) beneath the p-base region, (b) the thickness of p-base ($t_{BASE}$), (c) the doping concentration ($N_J$) and width ($W_J$) of a JFET region, (d) the doping concentration ($N_{EPI}$) and thickness ($t_{EPI}$) of epi-layer. Design parameters are optimized using 2D numerical simulations and the 4H-SiC DMOSFET structure results in high figure of merit ($V_B^2/R_{SP,ON}$>~$340MW/cm^2$) for a power MOSFET in $V_B{\sim}1200V$ range.

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Correlation Between Mandibular Condylar Process Fracture and Temporomandibular Joint (하악 과두 골절과 측두하악관절과의 관계)

  • Moon, Chul-Woong;Kim, Su-Gwan;Oh, Ji-Su
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.32 no.5
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    • pp.488-492
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    • 2010
  • This review evaluates the literature on the relationship between mandibular condylar process fracture and temporomadibular joint (TMJ). The topic of condylar fracture generated more discussion and controversy than any other field of maxillofacial trauma associated with TMJ. Disturbance of occlusal function, devia-tion of mandible, internal derangements of TMJ, and ankylosis of the joint with resultant inability to move the jaw are sequelae of condylar process fracture. Thus it is necessary to understand how the masticatory system adapts to the structural alterations that accompany fractures of the mandibular condyle. Treatment of condylar process fracture include two methods ; closed treatment and open treatment. If one chooses totreat closed, one must understand that adaptations in the musculature, skeleton, and dentition will be necessary. Open treatment of condylar process fractures probably requires fewer adaptations within the masticatory system to provide a favorable functional outcome. However, one must weigh the risk of open surgery against the possible improvement in outcome. The risks are not just surgical risk, but biological risk as well, such as disruption of the blood supply to the condyle. This review presents relevant aspects of change of TMJ associated with condylar process fracture.

A Study on the Analyzing Characteristic of Exhibition Space through Multivariate Analysis (다변량해석에 의한 상설전시공간의 속성파악에 관한 연구 -국립중앙박물관 상설전시공간의 성격에 대한 주성분분석-)

  • 임채진;이규황
    • Korean Institute of Interior Design Journal
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    • no.25
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    • pp.245-252
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    • 2000
  • Since the twentieth century, common exhibitions have experienced display replacements and apace alterations. As a result, not only the visual space background of the spectators but the structure systems and positions of the construction space have also been changed. With regards to common zones of the exhibition space, appropriate harmonization of spectators space, aisle space, and media space are closely related the effectiveness and propriety of display arrangement. A number of preceeding researches suggest exhibition first, construction next, regarding the order of the construction and exhibition of the museums and art galleries. However, a majority of the exhibition hall constructions in Korea have not been carried away based on these models. Thus, disharmony of constructions and exhibition space structures have caused numerous problems. The purpose of this research is to seek the countermeasures that can be used in the stage of planning for the museum constructions and exhibition space by suggesting, based on the above mentioned points, the development of the indicators and analyzing methods to understand the structural attributes of the common exhibition space through space syntax method and multivariate analysis.

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Cadmium removal by Anabaena doliolum Ind1 isolated from a coal mining area in Meghalaya, India: associated structural and physiological alterations

  • Goswami, Smita;Syiem, Mayashree B.;Pakshirajan, Kannan
    • Environmental Engineering Research
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    • v.20 no.1
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    • pp.41-50
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    • 2015
  • The cyanobacterium Anabaena doliolum Ind1 isolated from a coal mining site was tested for removal of cadmium at optimum pH 7.0 and temperature $25^{\circ}C$. The organism recorded high percentage of metal removal (92-69%) within seven days of exposure to 0.5-2.0 ppm cadmium. Biosorption onto the cell surface was the primary mode of metal removal. Fourier transform infrared spectroscopy (FTIR) established hydroxyl, amides, carboxyl, sulphate and carbonyl groups to be the major functional groups on the cell surface involved in cadmium binding. Cellular ultrastructure and a range of vital physiological processes (i.e., photosynthetic pigments, respiration, photosynthesis, heterocyst frequency and nitrogenase activity) remained unaffected upon 0.5 ppm treatment; higher concentrations of cadmium exerted visible adverse effects. Amongst the five photosynthetic pigments tested, phycocyanin was the most targeted pigment (inhibition was 15-89%). Both respiration and photosynthetic activities were inhibited by cadmium with more severe effect seen on respiration. 2.0 ppm cadmium exposure also had drastic negative effect on nitrogenase activity (87% decreased).

Bio-Economic Relationships between Climate Change and Fisheries (기후변화와 수산업의 관계에 관한 연구)

  • Park, Seong-Kwae;Kwon, Hyeok-Jun;Park, Jong-Wun;Cha, Cheol-Pyo
    • Journal of Fisheries and Marine Sciences Education
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    • v.22 no.3
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    • pp.388-401
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    • 2010
  • This research aims at analyzing impacts of climate change on fisheries. Climate change is an additional pressure on top of the many which fish stocks already experience. This implies that the impact of climate change must be evaluated in the context of other anthropogenic pressures, which often have a much greater and more immediate effect. Conversely, it is evident that fish stocks will be more resilient to climate impacts if the stresses due to other factors, such as over-fishing and pollution, are minimized. Improved management of fisheries and of marine ecosystems can undoubtedly play an important role in adapting to the impacts of climate change. Most of the improvements which are needed do not require new science or understanding, they require patient development of acceptable, effective, responsive social institutions and instruments for achieving adaptive management. Management advices must include complete and transparent information on risks and uncertainties which arise from data quality and from structural deficiencies in the assessment models. Well-designed and reliable monitoring of fish stocks and the marine ecosystem is essential in order to detect changes and give warning in advance of alterations in the productivity of individual species and of the structure and functioning of the ecosystem and fishery economy on which they depend.

A Study on the U-Korean Traditional Residence introduced Ubiquitous Services in a Traditional Residence (유비쿼터스 기반 U-한옥의 서비스모델 연구)

  • Joung, In-Sang;Lee, Kang-Hoon
    • Journal of the Korean Institute of Rural Architecture
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    • v.12 no.3
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    • pp.47-56
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    • 2010
  • In a study of a peculiarity of the Korean residence construction as the central Jeong Yeo Chang's Residence, we proposed varieties service models for an anthropocentric U-Korean style with "a convenience, a security, an economical, a pleasure". It was to assume for this research that was established in case of all necessity IT infrastructures, and was structural alterations to a Korean residence sectional. It was used for Wall-Pad(Home Gateway) for controlling services, gas valves, remote inspection of a meter, curtains, doorlocks, boilers, temperature controllers, indoor ventilation systems, breakers, and expansion of crime prevention, energy. With introducing various service models on U-Korean style house, removing a negative view about Korean residence, we drew the best suited residence condition combining with a merit of the Korean residence and the Ubiquitous Intelligent Home Service. In order to realize U-Korean style house at the right time at the right place, a maintenance was required to be ensured based on social infrastructures and institutions and laws.

Characterization of Protein Expression in the Head of Oryzias latipes in Response to Acute and Chronic Exposure to Benzo(a)pyrene

  • Oh, Jeong-Hwan;Moon, Hyo-Bang;Choe, Eun-Sang
    • Korean Journal of Environmental Biology
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    • v.26 no.3
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    • pp.220-225
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    • 2008
  • In this study, alterations in whole proteome expression patterns in the head of Japanese medaka (Oryzias latipes) was investigated following acute or chronic exposure to benzo(a)pyrene (BaP) (25 ${\mu}g$ L$^{-1}$) for 48 hrs and 15 days, respectively. The results showed that 9 and 6 protein spots were statistically different, relative to controls, in response to acute and chronic BaP exposure, respectively. In the acute exposure group, 5 spots were up regulated and 4 spots were downregulated, while in the chronic exposure group, 4 spots were upregulated and 2 spots were downregulated. Three of these spots were common to both the acute and chronic BaP exposure groups and were identified using LC-MS/MS followed by database searching. These 3 spots were found to be associated with structural proteins belonging to the actin and keratin families. These data suggest that acute and chronic exposures to BaP may affect tissue morphology in the head of Japanese medaka.

A study on the reduction of noise and vibration by acoustic resonance in the tube bank of a circulating fluidized bed combustion boiler (순환 유동층 보일러 관군의 음향공진에 의한 이상소음 발생 및 저감 연구)

  • Park, Eung-Kyu;Song, Keun-Bok;Kim, Won-Hyun;Joo, Won-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.10a
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    • pp.101-106
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    • 2011
  • In the present paper, the phenomena of abnormal noise and vibration due to acoustic resonance of CFBC(Circulating Fluidized Bed Combustion) boiler was presented. The acoustic resonance which occurred in the gas path of CFBC boiler system was caused by coincidence of vortex shedding frequency of tube bank and acoustic natural frequency of duct and hopper. And, the phenomena of beating arose from the interference of two closed resonant waves at 66.4Hz and 70.8Hz. There are two control methods for acoustic resonance in this system. The first method is to change the vortex shedding frequency from the structural alterations on the tube bank. And the second method is to change the acoustic natural frequency of the gas path with the installation of anti-noise baffles. The second one which is relatively easy to apply, was adapted in this study. As a result, the noise and vibration level have been decreased by 41dB and 94% at 66.4Hz, respectively. And the improvement of noise and vibration at 70.8Hz was identified by sensory evaluation.

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