• 천문학회지
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• 제37권4호
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• pp.211-216
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• 2004

We present the results of an H I aperture synthesis mosaic of the Large Magellanic Cloud (LMC), made by combining data from 1344 separate pointing centers using the Australia Telescope Compact' Array (ATCA) and the Parkes multibeam receiver. The resolution of the mosaiced images is 50" (<15 pc, using a distance to the LMC of 55kpc). This mosaic, with a spatial resolution .15 times higher than that which had been previously obtained, emphasises the turbulent and fractal structure of the ISM on the small scale, resulting from the dynamical feedback of the star formation processes with the ISM. We also have done a widefield panoramic survey of H$\alpha$ emission from the Magellanic Clouds with an imager mounted on the 16-inch telescope at Siding Spring Observatory. This survey produced H$\alpha$ images which are equal to the ATCA survey in area coverage and resolution. This survey allows us to produce a continuum-subtracted image of the entire LMC. In contrast with its appearance in the H$\alpha$ image, the LMC is remarkably symmetric in H I on the largest scales, with the bulk of the H I residing in a disk of diameter 8. $^{\circ}4$ (7.3 kpc) and a spiral structure is clearly seen. The structure of the neutral atomic ISM in the LMC is dominated by H I filaments combined with numerous shells and holes.

• 한국측량학회지
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• 제29권5호
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• pp.535-541
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• 2011

토석류는 집중호우시 산악지형에서 발생한 사면파괴 쇄설물 또는 계곡 내에 쌓여 있던 퇴적토가 많은 양의 물과 섞여 흐르는 현상으로서 이동경로나 퇴적지점에 있는 시설물, 가옥, 인명에 큰 피해를 유발한다. 본 연구에서는 해외에서 연구되었던 토석류 거동에 관련된 모형식을 국내 사례에 적용해 보았으며, 이를 위해 우리나라 강원도 인제군에서 발생한 산사태 및 토석류에 대해 항공사진과 GPS 현장 측량성과를 이용하여 발생부와 퇴적부 자료를 수집하였다. 분석한 결과 토석류 이동거리를 예측할 수 있는 L/H는 평균 4.93, 표준편차 0.97을 나타내었다. 토석류의 규모와 면적을 예측하는 경우 과대 산정되는 문제가 있으며 이는 우리나라의 토석류가 상부의 대규모 산사태로 유발되는 것이 아니고 다발적으로 발생한 소규모 산사태로 인한 것이기 때문인 것으로 보인다. 따라서 국내 산지 환경에 적합한 경험식에 대한 연구가 필요하다고 판단된다.

• 대한기계학회논문집A
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• 제35권11호
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• pp.1407-1413
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• 2011

소형풍력발전시스템의 복합재 블레이드에 대한 실규모 구조시험 및 이를 모사한 구조해석을 통하여 설계 타당성을 검증하였다. 먼저 IEC 61400-2 에 규정된 설계 요구조건의 만족을 위하여 정격 풍속 및 IEC 61400-2 Case H 의 최악 조건에 대한 구조해석을 수행하고 이를 통하여 적층 순서 및 적층 두께를 결정하였다. 또한 이러한 구조해석의 타당성 검증을 위하여 IEC 61400-23 에 따라 구조해석과 동일한 하중조건에서의 실규모 구조시험을 실시하였다. 이러한 실규모 구조시험을 통한 구한 블레이드의 하중-변위 선도 및 표면의 변형률 특성을 이용하여 블레이드의 구조적 안전성을 평가하였다.

• The Korean Journal of Pain
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• 제31권1호
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• pp.10-15
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• 2018

Background: To identify a new strategy for postoperative pain management, we investigated the analgesic effects of allopregnanolone (Allo) in an incisional pain model, and also assessed its effects on the activities of the primary afferent fibers at the dorsal horn. Methods: In experiment 1, 45 rats were assigned to Control, Allo small-dose (0.16 mg/kg), and Allo large-dose (1.6 mg/kg) groups (n = 15 in each). The weight bearing and mechanical withdrawal thresholds of the hind limb were measured before and at 2, 24, 48, and 168 h after Brennan's surgery. In experiment 2, 16 rats were assigned to Control and Allo (0.16 mg/kg) groups (n = 8 in each). The degree of spontaneous pain was measured using the grimace scale after the surgery. Activities of the primary afferent fibers in the spinal cord (L6) were evaluated using immunohistochemical staining. Results: In experiment 1, the withdrawal threshold of the Allo small-dose group was significantly higher than that of the Control group at 2 h after surgery. Intergroup differences in weight bearing were not significant. In experiment 2, intergroup differences in the grimace scale scores were not significant. Substance P release in the Allo (0.16 mg/kg) group was significantly lower than that in the Control group. Conclusions: Systemic administration of Allo inhibited mechanical allodynia and activities of the primary afferent fibers at the dorsal horn in a rat postoperative pain model. Allo was proposed as a candidate for postoperative pain management.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2285-2289
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• 2014

The solvolysis rate constants of 5-dimethylamino-naphthalene-1-sulfonyl chloride ($(CH_3)_2NC_{10}H_6SO_2Cl$, 1) in 31 different solvents are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale and $Y_{Cl}$ solvent ionizing scale with sensitivity values of $0.96{\pm}0.09$ and $0.53{\pm}0.03$ for l and m, respectively; the correlation coefficient value was 0.955. These l and m values can be considered to support an $S_N2$ reaction pathway having a transition state (TS) structure similar to that of the benzenesulfonyl chloride reaction. This interpretation is further supported by the activation parameters, i.e., relatively small positive ${\Delta}H^{\neq}$ (12.0 to $15.9kcal{\cdot}mol^{-1}$) and large negative ${\Delta}S^{\neq}$ (-23.1 to $-36.3cal{\cdot}mol^{-1}{\cdot}K^{-1}$) values, and the solvent kinetic isotope effects (SKIEs, 1.34 to 1.88). Also, the selectivity values (S = 1.2 to 2.9) obtained in binary solvents are consistent with the proposed mechanism.

• 한국표면공학회지
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• 제51권2호
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• pp.104-109
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• 2018

Fe-2 wt.%Ni alloys were fabricated by metal powder injection molding, and their oxidation behavior at $600-700^{\circ}C$ for 30 h in air was studied in order to find the effect of the small addition of Ni in the iron matrix on the high-temperature oxidation. Oxide scales that formed after oxidation consisted primarily of $Fe_2O_3$, where microscopic voids were scattered. Nickel was segregated initially at the scale/matrix interface, and later at the lower part of the $Fe_2O_3$ scale. At $600^{\circ}C$, Fe-2wt.%Ni alloys oxidized parabolically initially, and linearly after 15 h. At $650-700^{\circ}C$, they oxidized linearly from the initial period. Although Fe-2wt.%Ni alloys oxidized slower than pure iron, their oxidation rates were relatively fast.

• 동력기계공학회지
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• 제15권5호
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• pp.22-29
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• 2011

In this study, the damage mechanism of large scale steam turbine due to water induction was analyzed and recovery characteristics were reviewed. A turbine consists of the rotating rotor and the stationary casing, and the clearance between them is very small for the efficiency enhancement. If water induction, while relatively cold steam or water is introduced into turbine, occurs, the considerable humping is caused at the casing near the initial water induction point and that induces the rubbing between rotor and casing. Finally, it leads to the catastrophic failure. Bowed rotor has the different characteristics in the recovery depending on damage degree. The elastic deformation due to light rubbing is recovered by turning the rotor with 3 rpm under normal operation condition, but most plastic deformation due to rubbing deforms the local microstructure and that results in permanent deformation which could not be recovered under normal operation condition. Bowed rotor has diverse characteristics depending on the recovery method, and the method is empirical and needs the cutting edge technology. Careful recovery treatment of the rotor will eliminate the risks and secure the high quality rotor similar to new rotor. If any critical error is made during the recovery, the rotor would not be recovered permanently and it should be scrapped.

• 소성∙가공
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• 제18권2호
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• pp.144-149
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• 2009

Recently, the monitoring technology of machining process is very important to improve productivity and quality in manufacturing filed. Such monitoring technology has been performed to measurement using vibration signal, acoustic emission signal and tool dynamometer. However, micro machining is limited small-scale parts machining because micro tool is very small and weakness to generate signal in micro machining process. Therefore, this study has efficient sensing technology for real monitoring system in micro machine that is proposed to supplement a disadvantage of single-sensor by multi sensor. From experimental result, it was evaluated tool wear and cutting situation according to repetitive slot cutting condition and changing cutting condition, and it was performed monitoring spindle rpm and condition according to compare acceleration signal with current signal.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.382-389
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• 2000

The purpose of present study is to investigate for reducing pressure fluctuations in tile case of installing tile air-shafts on the side wall of the tunnel with small cross-sectional area on conventional line. Experiments were performed with a 1/61-scale moving model rig for the tunnel of 0.764km length in the condition of tunnel cross-section area of 28 ㎡ According to the results, the maximum pressure fluctuation is reduced by 45% for 19 air-shafts. This results have the speed-up effects of about 33.4km/h for the train running in tunnel.

• 수산해양교육연구
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• 제20권3호
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• pp.487-499
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• 2008

This study was analyzed and assessed the environmental factors on small marine ranching sites around Gunsan Coast, West Sea of Korea. Standards of assessment are followed in the reports on the choice of marine ranching sites and regulation factors of proper site on marine artificial reefs of MOMAF. Max. current speed around Gunsan were ranged between 25.52 ~ 57.49cm/sec. These values were satisfied by comparing assessment factor such as current speed.. Factors of temperature, salinity, transparency and pH were evaluated as the proper extent. DO was not distributed as the proper extent due to different criterion. between the same assessment factor. COD, SS and nutrients were partly suited to the criteria. Especially, SS was almost higher than that of criterion. So, we are proposed to be reflected in environment characteristics of West Coast such as SS. Moreover, the extent of pollution load factors have to be specified clearly in the regulations of assessment criteria.