• Journal of Welding and Joining
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• v.2 no.1
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• pp.58-65
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• 1984

NGW(Narrow Gap Welding)는 개선폭이 약 9mm로서 연강 및 저탄소강을 용접할 경우 두께가 300mm까지 1층으로 용접이 가능하다. 따라서 두께가 두꺼운 발전설비, 원자력 설비, 화학 설비 등의 압력용기의 용접에 적합한 용접법이다. 그러나 실제적인 NGW의 적용은 제작자의 친근 감의 결여, 기술 부족 및 복잡성 등의 이유로 아직도 비교적 널리 활용되지 않고 있다. 새로운 type의 GMAW-NG process가 발전되어 오고 잇다. 위와 같은 장점과 단점을 비교해 볼 때 낮은 operating 경비, 높은 joint filling rate, 변형과 잔류 응력의 감소 등으로 세계적인 용접 전 문가들의 계속적인 관심도가 높아지고 사용도도 증가하고 있다. narrow gap welding의 장단점을 요약하면 아래와 같다. 장 점 1) 생산성이 높다. 2) 고품질을 얻을 수 있다. 3) 잔류 응력과 변형을 적게 한다. 4) 전자세 용접이 가능하다. 단 점 1) 용접기의 가격이 비싸다. 2) 용접 품질에 큰 영향을 주는 아아크가 작업 조건에 따라 민감하게 변한다. 3) repair procedure는 다른 용접 방법을 요구한다. 4) 과도한 복잡성 때문에 장비의 신뢰성이 낮다.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.153-162
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• 2016

Experimental investigation was carried out on the CHF(Critical Heat Flux) under downward flow condition in narrow rectangular channels simulating subchannel of plate-type-fuel for JRTR(Jordan Research and Training Reactor). The experiments covers the license requirement of the research reactor. Two test sections used in this study simulate full scale subchannels for fission moly uranium target and plate-type-fuel, respectively. From the experimental results, the parameters affecting on the CHF are investigated. By using experimental data, the existing CHF prediction models were evaluated. Finally, the applicability of correlations were analysed to predict CHF in the narrow rectangular channel under the downward flow condition.

• ALGAE
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• v.27 no.4
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• pp.235-247
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• 2012

Regardless of continuous researches, recent researches on the genus Eucampia (Bacillariophyceae) have focused mainly on E. zodiacus f. zodiacus In the present study, species of the genus Eucampia have been studied based on their morphological characteristics. Eucampia species were collected at 24 sites from July 2008 to June 2011 in Korean coastal waters. Species were mainly identified based on the shape of valve, ocellus, and aperture, along with the length and shape of the bipolar elevations. As a result, five Eucampia species were identified: Eucampia cornuta, E. groenlandica, E. zodiacus f. zodiacus, E. zodiacus f. cylindrocornis, and E. zodiacus var. cornigera. E. cornuta and E. groenlandica have long pervalvar axis length, but the others display short or moderate length. Ocellus shape of E. cornuta, E. groenlandica and E. zodiacus f. cylindrocornis are linear ribs, whereas E. zodiacus f. zodiacus and E. zodiacus var. cornigera have radial ribs with central area. E. cornuta and E. zodiacus f. cylindrocornis have long and narrow cylindrical elevations. E. groenlandica and E. zodiacus f. zodiacus have short and broad elevations with blunt tips. E. zodiacus var. cornigera has long and broad conical elevations. In terms of aperture shape, E. cornuta has large elliptical form, E. groenlandica has almost circular to rounded rectangular form, E. zodiacus f. zodiacus has narrow and elliptical rounded rectangular to a narrow lanceolate form, E. zodiacus f. cylindrocornis has almost rectangular form, and E. zodiacus var. cornigera has rounded rhombic form. On the basis of elevations in broad girdle view, 5 Eucampia taxa could be divided into 3 types: 'narrow H type', E. cornuta and E. groenlandica; 'regular H type', E. zodiacus f. cylindrocornis and E. zodiacus var. cornigera (partial); 'wide H type', E. zodiacus f. zodiacus (almost).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.488-493
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• 2008

This paper represents a dual-mode type transmission technique for a high reliable narrow-band power line communication(PLC) modem, and its design and implementation of a system-on-chip(SoC). The proposed transmission technique is based on a Chirp modulation for the purpose of overcoming time variations of power line channel environments in the narrow-bandwidth of the frequency range of 95-145.5 kHz. The designed modem is fabricated utilizing a mixed 0.18 ${\mu}m$ CMOS technology. Especially, according to the power line channel environments the data transmission rate can be selectively changed into 2.5 kbps and 480 bps. The total hardware complexity of the implemented chip is about 50,000 gates, the power consumption is about 26mW, and the operating frequency is up to 5.12 MHz.

• The KSFM Journal of Fluid Machinery
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• v.2 no.3 s.4
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• pp.37-44
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• 1999

In a screw-type centrifugal pump, the pump head deteriorates from single-phase flow to the choke due to an increased air entrainment at a wide tip clearance compared to that of a narrow tip clearance. Moreover, at a narrow tip clearance, the pump head became partially higher in a two-phase flow than that of a single-phase flow near the best efficiency point in low void fraction region. Therefore, we observed the internal flow pattern by using a stroboscope and we measured the mean size of bubbles from the images obtained with a high speed camera. Then, we investigated the influences of the mean size of bubbles, tip clearances and flow patterns on pump performance.

• Journal of architectural history
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• v.7 no.4 s.17
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• pp.9-27
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• 1998

The urban form of Korean cities significantly changed in the late Chosun dynasty. The influence of commercial development was the main cause of these changes. Commerce became a important function of existing cities, and the new type of commercial towns emerged at the important spots of traffic routes. In both cases streets became dominant element of urban form. Mainly commercial buildings aggregated along the streets, and to obtain higher land use intensity shape of lots became narrow and deep. Koyang(高陽) shows the most significant example of this new type of lot and lot pattern. Approximately 30 narrow and deep type of lots lined on each side of street forming about 390 meters long linear commercial town. Similar examples were found at the outside of south gate of Suwon(水原), Nuwon(樓院), and Pangyo(板橋).

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.1
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• pp.43-52
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• 2014

P-wave characteristic in the human electrocardiogram (ECG) is important in the diagnosis of atrial conduction pathology. In this paper, we measured an ECG signal from patient with cardiovascular disease using one lead ECG electrode system which is based on the wireless cardiac monitoring system. And we detected a P-wave in ECG signal using the complex-valued continuous wavelet transforms (CWT) according to two kinds of patch type electrodes such as an existing narrow patch type electrode and the improved wide patch type electrode presented in this paper. Also, we compared the characteristics in detecting the P-wave in terms of the magnitude and the width of P-waves. From the results of comparison we found that the width and the magnitude of P-wave detected using the wide patch type electrode is improved to be interpreted easier compared to those using the narrow patch type electrode. Furthermore, we have also proven that the complex-valued CWT can be used as a robust detector for P-wave in ECG signal analysis.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.5
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• pp.628-636
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• 1999

This work describes the low-resolution spectral modeling of the water vapor, carbon dioxide and their mixtures by applying the weighted-sum-of-gray-gas-gases model (WSGGM) to each narrow band. Proper modeling scheme of gray gas absorption coefficients vs temperature relation is suggested. Comparison between the modeled emissivity calculated from this relation and the 'true' emissivity obtained from the high temperature statistical narrow band parameters is made for a few typical narrow bands. Low resolution spectral intensities from one-dimensional layers are also obtained and examined for uniform, parabolic and boundary layer type temperature profiles using the obtained WSGGM's with several gray gases. The results are compared with the narrow band spectral intensities obtained by a narrow band model-based code with Curtis-Godson approximation. Good agreement is found between them. Data bases including optimized modeling parameters and total and low-resolution spectral weighting factors are developed for water vapor, carbon dioxide and their mixtures. This model and obtained data bases, available from the authors' Internet site, can be appropriately applied to any radiative transfer equation solver.

• The Bulletin of The Korean Astronomical Society
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• v.31 no.1
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• pp.46.2-46.2
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• 2006

• Fashion & Textile Research Journal
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• v.22 no.3
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• pp.378-385
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• 2020

The purpose of this study was to present basic data for development of shoe last suitable for women of plus size (BMI 25 kg/㎡ or higher) by type and to analyze the characteristics of each type of foot type. The results of the study are as follows. A comparison of the feet of a plus-size woman and a normal-weight woman showed that the feet of a plussize woman were thicker and wider in the toes, cheeks and feet than those of a normal-weight woman, while the ankle area was thicker. As a result of the cluster analysis by type of foot type of plus-size woman, type 1 was classified into four types, type 1 was 49 (19.5%), type 2 was 43 (17.1%), type 3 was 53 (21.1%), and type 4 was distributed among 106 (42.2%). Type 1 appeared to be a long, low heel, thick foot and wide H-type, and Type 2 appeared to be a D-type with a low heel and a thinner and narrow foot compared to other types, but with wide outer width of the foot. Type 3 showed short feet, low heels, narrow feet, but slanted sides, and Type 4 showed type A with long feet, high heels, thick and wide feet or a combination of toes.