• 제목/요약/키워드: Ground observation

검색결과 656건 처리시간 0.026초

EFFECTS OF THE ION BEAM ASSISTED DEPOSITION OF HYDROXYAPATITE ON OSSEOINTEGRATION OF THE ENDOSSEOUS IMPLANTS IN RABBIT TIBIAE (이온빔 보조 전자빔 수산화 인회석 증착이 골내 임플란트의 골유착에 미치는 영향)

  • Jung, Young-Chul;Han, Chong-Hyun;Lee, In-Seop;Lee, Hyeon-Jeong;Kim, Myeong-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • 제38권5호
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    • pp.659-674
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    • 2000
  • A large increase in the use of thin film coating of hydroxyapatite(HA) in implant dentistry is driven by the desire to take advantage of the excellent biocompatibility and high strength of HA coating. The purpose of this study was to evaluate the effects of HA-coated implants by ion Beam Assisted Deposition(IBAD) method in comparison to the sand-blasted and machined surfaces. Osteoblast culture test, removal torque test and histomorphometric analysis were performed and the following results obtained; 1. Examination of the osteoblast cultures displayed no difference in the secretion of alkaline phosphatase between the various specimen, but IBAD with pure HA specimen showed low alkaline phosphatase secretion(p<0.05). 2. Removal torque tests showed HA-coated implants by IBAD method to be similar in high value to the implants with sand-blasted surface than the implants with machined surface. And the ovariectomized group showed low mechanical test value than the normal group(p<0.05). 3. Histomorphometrical comparisons were performed on undecalcified ground sections. HA-coated implants by IBAD method demonstrated the highest mean bone-to-metal contact ratio on all threads and 3-best consecutive threads, and the implants with sand-blasted surface and implants with machined surface was in the next consecutive order(p<0.05). HA-coated implants showed slightly higher bone-to- metal contact ratio than sand-blasted implants, but no statistically significant difference was obtained between the two materials. The ovariectomized group showed lower value of bone-to-metal contact ratio than the normal group, but no statistically significant difference was obtained between the two groups. 4. Evaluation of bone volume on all threads and 3-best consecutive threads showed no statistically significant difference among the different surface treatment groups, but showed lower bone volume in ovariectomized group than in the normal group(p<0.05). According tn these results, thin film coated implants with HA showed high bone contact ratio, bone volume and removal torque strength in the short term, but long term observation is needed.

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Analysis of the Effect of Pavement Crack Depth of the Cavity Management Grade (포장 균열 깊이가 공동 관리 등급에 미치는 영향 분석)

  • Park, Jeong Jun
    • Journal of the Society of Disaster Information
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    • 제16권3호
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    • pp.449-457
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    • 2020
  • Purpose: The Seoul Metropolitan Government classifies the cavity risks into emergency, priority, general, and observation grades in consideration of the cavity size, asphalt pavement thickness, and pavement depth based on the cavity management grade criteria of Seoul. In this study, the depth of cracking was measured at 17 cracks identified by checking the pavement condition of the cavity at 265 cavities found in the 2019 cavity investigation service. Method: In the first phase, crack width and depth were measured using a vernier caliper, taper gauge, and depth gauge to check the cracks of the identified cavities. In the second phase, the location of the largest crack in the upper road surface was confirmed, and A.C. was drilled to further measure the crack depth. Results: As a result, the cavity management level was raised in nine of the 17 test cavity identified. Therefore, in case of emergency and priority recovery, the grade should be adjusted according to the depth of pavement crack and the thickness of residual A.C. pavement. Conclusion: In the case of cracks in the upper part of the cavity, the crack progression must be determined through the perforation and the remaining asphalt concrete thickness must be determined to determine the cavity grade.

Positioning Accuracy Analysis of KOMPSAT-3 Satellite Imagery by RPC Adjustment (RPC 조정에 의한 KOMPSAT-3 위성영상의 위치결정 정확도 분석)

  • Lee, Hyoseong;Seo, Doochun;Ahn, Kiweon;Jeong, Dongjang
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • 제31권6_1호
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    • pp.503-509
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    • 2013
  • The KOMPSAT-3 (Korea Multi-Purpose Satellite-3), was launched on May 18, 2012, is an optical high-resolution observation mission of the Korea Aerospace Research Institute and provides RPC(Rational Polynomial Coefficient) for ground coordinate determination. It is however need to adjust because RPC absorbs effects of interior-exterior orientation errors. In this study, to obtain the suitable adjustment parameters of the vendor-provided RPC of the KOMPSAT-3 images, six types of adjustment models were implemented. As results, the errors of two and six adjustment parameters differed approximately 0.1m. We thus propose the two parameters model, the number of control points are required the least, to adjust the KOMPSAT-3 R PC. According to the increasing the number of control points, RPC adjustment was performed. The proposed model with a control point particularly did not exceed a maximum error 3m. As demonstrated in this paper, the two parameters model can be applied in RPC adjustment of KOMPSAT-3 stereo image.

Light Emission and Plasma Property in the External Electrode Fluorescent Lamps (외부전극 형광램프의 발광 및 플라즈마 특성)

  • Ahn, S.;Lee, M.;Jeong, J.;Kim, J.;Yoo, D.;Koo, J.;Kang, J.;Hong, B.;Choi, E.;Cho, G.
    • Journal of the Korean Vacuum Society
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    • 제16권3호
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    • pp.172-180
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    • 2007
  • A new diagnostics of plasma electron temperature and plasma density is introduced with the observation of the light emission along the tube of external electrode fluorescent lamps. With two different methods operating an external electrode fluorescent lamp of outer diameter 4.0 mm and length 860 mm for the back-light source of 37-inch LCD-TVs, the lighting modes and the plasma properties are investigated. In the center balance operation, the light-emission propagates simultaneously from both sides of the high voltage electrodes to the center of the lamp, while in conventional operation the light-emission propagates from the one end of a high voltage to the other ground electrode. In the operation value of luminance $10,000{\sim}15,000cd/m^2$, the electron plasma thermal energy $(kT_e)$ is about $1.3{\sim}2.7eV$ with the electron density $(n_e)$ is about $(1.6{\sim}3.6){\times}10^{16}m^{-3}$.

THE EFFECT OF ETCHING TIME ON SHEAR BOND STRENGTH AND ADAPTIBILITY OF ONE-BOTTLE DENTIN ADHESIVE (One-bottle 상아질 접착제의 전단결합강도와 접착성에 관한 부식시간의 효과)

  • Park, Kwang-Soo;Park, Il-Yoon;Cho, Young-Gon
    • Restorative Dentistry and Endodontics
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    • 제24권1호
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    • pp.240-250
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    • 1999
  • The purpose of this study was to evaluate the effect of different etching time on the shear bond strength and adaptibility of composite to enamel and dentin when used one-bottle adhesive Prime & Bond$^{TM}$ 2.0. The proximal and occlusal surfaces of 88 extracted human molars were ground to expose enamel(n=44) and dentin (=44) using diamond wheel saw. Teeth were randomly assigned to four test groups(n=11) and received the following treatments : Control group were conditioned with 36% phosphoric acid for 20 sec. according to the manufacturer's directions. Experimental 10 sec. group, 30 sec. group and 60 sec. group were conditioned with 36% phosphoric acid for 10 sec., 30 sec. and 60 sec., respectively. Teeth were rinsed and dried for 2 sec. Prime & Bond$^{TM}$ 2.0 were applied according to the manufacturer's directions and Spectrum$^{TM}$ TPH composite resins were bonded to enamel and dentin surfaces. All specimens were stored in distilled water for 24 hours. Eighty specimens were sheared in a Universal Testing Machine with a crosshead speed of 5mm/minute. One way ANOVA and LSD test were used for statistical analysis of the data. Failure modes of all specimens after shear bond strength test were examined and listed. Also, representive postfracture modes and eight specimens were examined under scanning electron microscope. The results of this study were as follows: 1. The shear bond strength to enamel was the highest value in 30 sec. group (20.68${\pm}$8.54MPa) and the lowest value in 10 sec. group (14.92${\pm}$6.07MPa), so there was significant difference of shear bond strength between two groups (p<0.05). But there was no significant difference among other groups (p>0.05). With longer etching time to enamel from 10 sec. to 30 sec., higher the shear bond strength was obtained, but the shear bond strength was decreased at 60 sec. etching time. 2. The shear bond strength to dentin was the highest value in control group (13.08${\pm}$6.25MPa) and the lowest value in 60 sec. group (9.47${\pm}$3.35MPa), but there was no significant difference among the all groups (p>0.05). The eching time over 20 sec. decreased the shear bond strength to dentin. 3. In SEM observation, the enamel and resin interfaces were showed close adaptation with no relation to etching time of enamel. And the dentin and resin interfaces were showed close adaptation at 20 sec. and 30 sec. etching time, but showed some gaps at 10 sec. and 60 sec. etching time. Accordingly, these results indicated that a appropriate etching time in Prime & Bond$^{TM}$ 2.0 was required to be 30 sec. in enamel and 20 sec. in dentin for the high shear bond strength and good adaptation between the composite resin and tooth substance.

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A Study on the Use Impact on the Trail in Gwanak Mountain, Korea (관악산 등산로 이용에 따른 영향에 관한 연구)

  • Yoo, Ki-Joon
    • Korean Journal of Environment and Ecology
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    • 제25권1호
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    • pp.111-117
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    • 2011
  • The purpose of this study is to establish trail use impact indicators, and evaluate the degree of use impact based on the understanding of the causality among the impacts on the spot. Theoretical reviews developed three indicators in terms of three ecological impacts, four physical impacts, and five sociological impacts, respectively. With this indicators, observation and questionnaire survey were employed on Gwanak Mountain Trail to measure the levels of impacts forementioned. As for the ecological impact, Some loss of ground cover vegetation was reveled near the trail due to trail use, however the level of disturbance by the naturalized and exotic plants was insignificant. Physical impacts such as soil hardness, enlargement of trail width were found intensified. The result of measuring sociological impacts showed visitors had expected higher level of crowding and encounters before their visit, therefore overall satisfaction level was positive, despite higher awareness level of actual crowding. Intensified continuing use of the trail is aggravating ecological and physical impacts on Gwanak Mountain trail, because of its location in a metropolitan area. Sociological impacts seem favorable at present, however if ecological and physical impacts were deteriorated, sociological impacts would also be affected. To maintain the quality level of use experience, managerial efforts to improve climbing culture as well as ecological and physical environment such as restoration of damaged areas are needed.

Characterization of Brugmansia mosaic virus Isolated from Brugmansia spp. in Korea (국내 브루그만시아에서 분리한 Brugmansia mosaic virus의 특성)

  • Park, Chung Youl;Kim, Bong-Sub;Nam, Moon;Lee, Min-A;Baek, Da-Som;Bae, Yang Su;Park, Eun-Hye;Kim, Jeong-Sun;Choi, Jong-Yoon;Lim, Seungmo;Moon, Jae Sun;Lee, Su-Heon
    • Research in Plant Disease
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    • 제20권4호
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    • pp.307-313
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    • 2014
  • In May 2013, an angel's trumpet leaves showing mosaic and malformation symptoms were collected from Suwon city, Gyeonggi-do. An analysis of the collected sample by transmission electron microscopy observation showed filamentous rod particles of 720-800 nm in length. On the basis of the these observations, we performed PCR against three reported Potyviruses (Brugmansia mosaic virus, Colombian datura virus and Brugmansia suaveolens mottle virus), and the sample was positive for BruMV. Pathogenicity and host range test of BruMV was determined by mechanical inoculation. Solanaceae (tobacco, tomato and eggplant) and Amaranthaceae (ground cherry) appeared typical virus symptoms. To determine coat protein of this virus, we designed specific primer pairs, and performed PCR amplification, cloning, and sequencing. Phylogenetic analysis showed that BruMV-SW was most closely related to BruMV isolate SK. Comparison of the BruMV-SW coat protein nucleotide sequences showed 92% to 99% identities to the other BruMV isolates.

Validation of Complementary Relationship Hypothesis for Evapotranspiration in Multipurpose Dam Basins (다목적댐유역에서의 증발산 보완관계가설 검증)

  • Kim, Jihoon;Kang, Boosik;Kim, Jin-Gyeom
    • KSCE Journal of Civil and Environmental Engineering Research
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    • 제37권3호
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    • pp.549-559
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    • 2017
  • The complementary relationship hypothesis for areal evapotranspirations was validated in the regional-scale area of multipurpose dam basins in Korea and the long-term water balances were indirectly identified. Annual actual evapotranspiration ($ET_A$) was assumed the difference between total annual precipitation and total annual inflow and the available moisture was assumed the total precipitation. The seasonally varying pan coefficient (kp) is estimated as the ratio of the $ET_{pan}$ and the evapotranspiration calculated by FAO Penman-Monteith equation ($ET_{PM}$). The complementary relationships using ground observation data of $ET_P$ and $ET_A$ in the multipurpose dam basins follow generally the typical pattern that $ET_P$ and $ET_A$ is complementary and converges to equivalent evapotranspiration ($ET_W$) under the extreme wet environment. However, $ET_A$ of Juam dam was estimated relatively greater than other basins and exceeds even $ET_P$ at certain range with high moisture availability, which can be understood as the results of possible over-estimation of precipitation or under-estimation of dam inflow. It is expected that the use of evapotranspiration complementary relationship for validating hydrological water balances will contribute to controlling uncertainties in estimating dam inflows during flood season in particular.

Effects an Acoustical Equipment on the Luring of Fish School (음향집어기의 집어 효과)

  • 장선덕
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • 제22권4호
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    • pp.75-82
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    • 1986
  • A field experiment was carried out to clarify the effect of underwater sound on the luring of fish school. The effects of. the acoustic emission on the luring of fish school were checked actually at a set net fishing site in Namhae using a commercial acoustic equipment, Dairyo-8. An emitting system of sound was designed by the authors, and the ambient noise, the sound pressure level and the reaction of fish school were measured in the set net. 1. The predominent frequency band of ambient noise was 150Hz-400Hz,.and the sound emitted was 400Hz-100Hz. The sound pressure level of ambient noise in set net was higher at the landing part, and lower at the playgrond, the gate of court and "the enterance of inclined "passage. The ambient noise was increased with the time elapse-d at the stage of hauling net, but :it was decreased suddenly at the final stage due probably to the decrease of the swimming speed of the fish school. 2. The results of the observation and the recording paper of echo sounder indicate that the effect of emitting sound in the bag net of set net was remarkable for the luring of fish school in the early stage, but decreased after 30 minutes. The reaction of fish school is more sensitiv2 to the sound pressure level than the time intervals between the emission and the pause. For the purpos~ of practical use, it is nesessary to confirm what kind of sound pressure level is the best for the luring of fish school. 3. In response to the acoustic equipment(Dairyo-8), fish school started to swarm 20 minutes after the sound emission and scattered when the sound paused. As the emitting pattern of the acoustic equiment, the three seconds of emission after one second of pause was more effective than the continuous emission at the set net fishing ground. Catch of the fish(s during th~ sound ernissio:l at the gate of court was three to five times more than that of no emission.

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Analysis of Data Characteristics by UAV LiDAR Sensor (무인항공 LiDAR 센서에 따른 데이터 특성 분석)

  • Park, Joon-Kyu;Lee, Keun-Wang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • 제21권5호
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    • pp.1-6
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    • 2020
  • UAV (Unmanned Aerial Vehicles) are used widely for military purposes because they are more economical than general manned aircraft and satellites, and have easy access to the object. Recently, owing to the development of IT technology, UAV equipped with various sensors have been released, and their use is increasing in a wide range of fields, such as surveying, agriculture, meteorological observation, communication, broadcasting, and sports. An increasing number of studies and attempts have made use of it. On the other hand, existing research was related mostly to photogrammetry, but there has been a lack of analytical research on LiDAR (Light Detection And Ranging). Therefore, this study examined the characteristics of a UAV LiDAR sensor for the application of a geospatial information field. In this study, the performance of commercialized LiDAR sensors, such as the acquisition speed and the number of echoes, was investigated, and data acquisition and analysis were conducted by selecting Surveyor Ultra and VX15 models with similar accuracy and data acquisition distances. As a result, a DSM of each study site was generated for each sensor, and the characteristics of data density, precision, and acquisition of ground data from vegetation areas were presented through comparison. In addition, the UAV LiDAR sensor showed an accuracy of 0.03m ~ 0.05m. Hence, it is necessary to select equipment considering the characteristics of data for effective use. In the future, the use of UAV LiDAR may be suggested if additional data can be obtained and analyzed for various areas, such as urban areas and forest areas.