• Structural Engineering and Mechanics
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• 제44권1호
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• pp.51-60
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• 2012

Concrete sleepers are essential components of the conventional railway. As support elements, sleepers are always subjective to a variety of time-dependent loads attributable to the train operations, either wheel or rail abnormalities. It has been observed that the sleepers may deteriorate due to these loads, inducing the formation of hairline cracks. There are two areas along the sleepers that are more prone to crack: the central and the rail seat sections. Several non-destructive methods have been developed to identify failures in structures. Health monitoring techniques are based on vibration responses measurements, which help engineers to identify the vibration-based damage or remotely monitor the sleeper health. In the present paper, the dynamic effects of the cracks in the vibration signatures of the railway pre-stressed concrete sleepers are investigated. The experimental modal analysis has been used to evaluate the modal bending changes in the vibration characteristics of the sleepers, differentiating between the central and the rail seat locations of the cracks. Modal parameters changes of the 'healthy' and cracked sleepers have been highlighted in terms of natural frequencies and modal damping. The paper concludes with a discussion of the most suitable failure indicator and it defines the vibration signatures of intact, central cracked and rail seat cracked sleepers.

• Smart Structures and Systems
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• 제14권4호
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• pp.719-741
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• 2014

Monitoring surface cracks is important to ensure the health of concrete structures. However, traditional visual inspection to monitor the concrete cracks has disadvantages such as subjective inspection nature, associated time and cost, and possible danger to inspectors. To alter the visual inspection, a complete procedure for automated crack assessment based on adaptive digital image processing has been proposed in this study. Crack objects are extracted from the images using the subtraction with median filter and the local binarization using the Niblack's method. To adaptively. determine the optimal window sizes for the median filter and the Niblack's method without distortion of crack object an optimal filter size index (OFSI) is proposed. From the extracted crack objects using the optimal size of window, the crack objects are decomposed to the crack skeletons and edges, and the crack width is calculated using 4-connected normal line according to the orientation of the local skeleton line. For an image, a crack width nephogram is obtained to have an intuitive view of the crack distribution. The proposed procedure is verified from a test on a concrete reaction wall with various types of cracks. From the crack images with different crack widths and patterns, the widths of cracks in the order of submillimeters are calculated with high accuracy.

• 한국잡초학회지
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• 제10권3호
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• pp.171-178
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• 1990

Thiobencarb에 대한 벼의 내성(耐性)을 예측(豫測)하는데에 여러 가지 농업적(農業的) 형질(形質)의 중요도(重要度)를 구명키 위하여 thiobencarb에 반응(反應)을 달리하는 44품종(品種)을 대상(對象)으로 제초제(除草劑)를 처리(處理)하여 제특성(諸特性)을 조사(調査)하였던 결과(結果)를 요약(要約)하면 다음과 같다. Thiobencarb 처리(處理])에 의한 초장(草長), 분얼수(分蘖數), 간장(桿長), 이삭수, 이삭당 영화수(穎花數)의 내성(耐性) 및 감수성(感受性) 품종(品種)간 차이(差異)는 제초제(除草劑) 처리농도(處理濃度)가 높을 때 더 크게 나타났으나, 출수기(出穗期), 등숙율(登熟率)은 제초제(除草劑) 처리농도(處理濃度)에 영향(影響)을 받지 않았다. Thiobencarb 고농도(高濃度) 처리(處理)에서 초장(草長), 분얼수(分蘖數), 등숙율(登熟率)을 제외한 모든 형질(形質)에 대한 회귀계수(回歸係數)는 유의성(有意性)을 보였으며 thiobencarb 농도(濃度)에 관계없이 고도(高度)의 정(正)의 유의성(有意性)을 보인 이삭당 영화수(穎花數)와 이삭수가 thiobencarb에 반응을 달리한 품종들의 수량(收量)을 에측하는데 가장 유용(有用)한 요소(要素)로 나타났다.

• 천문학논총
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• 제20권1호
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• pp.143-149
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• 2005

KASI (Korea Astronomy and Space Science Institute) is developing the near-infrared camera system named KASINICS (KASI Near-Infrared Camera System) which will be installed at the 60cm f/13.5 Ritchey-Chretien telescope of the Sobaeksan Optical Astronomy Observatory (SOAO). The camera system is optimized for JHKL bands and has a 6 arcmin FOV. The optical system consists of two spherical mirrors and a 8-position filter wheel. With the exception for the dewar window, all optical elements are cooled inside cryogenic dewar. Since the Offner system is adopted to prevent thermal noises from outside of the telescope primary mirror, the secondary mirror of the Offner system acts as a cold Lyot stop. The optical performance does not change by temperature variations because the Aluminum mirrors contract and expand homogeneously with its mount. We finished the design and fabrication of the optical parts and are now aligning the optical system. We plan to have a test observation on 2006 January.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1703-1706
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• 1996

The purpose of this study is to research and develop polypyrrole(PPy) positive for thin film rechargeable lithium battery. We investigated cyclic voltammetry, AC impedance response and charge/discharge cycling of PPy/SPE/Li cells as a function of temperature. The redox capacity of $PPy/CF_{3}SO_{3}$ film was the most large. The discharge capacity of PPy/SPE/Li cell with $PPy/CF_{3}SO_{3}$ film was higher than those of $PPy/ClO_{4}$ and $PPy/AsF_6$ films at all cycles. The energy density of PPy/SPE/Li cells during 1st cycle was 73, 90 and 101Wh/kg at $25^{\circ}C$, $45^{\circ}C$ and $60^{\circ}C$, respectively. The improvement of energy density is due to reduction of charge-transfer resistance associated doping-undoping process in PPy film with Increasing temperature. $PPy/CF_{3}SO_{3}$ film shows a good property on charge/discharge cycling in PEO-$LiClO_4$-PC-EC electrolyte.

• 한국의류산업학회지
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• 제18권5호
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• pp.564-576
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• 2016

This study analyzes and classifies dresses by fashion designers worn in 10 fashion show seasons for haute-couture finales over the last five years(from 2011 S/S to 2015 F/W). The analysis of dresses are divided into 6 sections: classic image brands, new launching brands, designer's image changing brands, continuous image brands, reentry collections brands, and non-continuous participated collection brands. In addition, fashion designer dress types based on this analysis are as follows. First, the type of individual image displayed positively appeals individual identity in fashion shows when wearing clothes like a fashion icon or model. Second, the type of personality orientation shows the personal image of the fashion designer rather than a brand image when expressing a favorite dress. Third, the type of reflecting the season trend shows seasonal trends by wearing a similar dress that match with the fashion show theme. Fourth, the type of consistent brand image means a dress by a fashion designer that meets a characteristic image of a brand that appeals to many people. Fifth, the type of original and typical fashion designer is a casual style(like a shirt and pants) that most people consider a fashion designers dress when leading and operating their own fashion show.

• Restorative Dentistry and Endodontics
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• 제43권1호
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• pp.3.1-3.10
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• 2018

Objectives: The aim of this study was to compare root canal volume change and canal transportation by Vortex Blue (VB; Dentsply Tulsa Dental Specialties), ProTaper Next (PTN; Dentsply Maillefer), and ProTaper Universal (PTU; Dentsply Maillefer) nickel-titanium rotary files in curved root canals. Materials and Methods: Thirty canals with $20^{\circ}-45^{\circ}$ of curvature from extracted human molars were used. Root canal instrumentation was performed with VB, PTN, and PTU files up to #30.06, X3, and F3, respectively. Changes in root canal volume before and after the instrumentation, and the amount and direction of canal transportation at 1, 3, and 5 mm from the root apex were measured by using micro-computed tomography. Data of canal volume change were statistically analyzed using one-way analysis of variance and Tukey test, while data of amount and direction of transportation were analyzed using Kruskal-Wallis and Mann-Whitney U test. Results: There were no significant differences among 3 groups in terms of canal volume change (p > 0.05). For the amount of transportation, PTN showed significantly less transportation than PTU at 3 mm level (p = 0.005). VB files showed no significant difference in canal transportation at all 3 levels with either PTN or PTU files. Also, VB files showed unique inward transportation tendency in the apical area. Conclusions: Other than PTN produced less amount of transportation than PTU at 3 mm level, all 3 file systems showed similar level of canal volume change and transportation, and VB file system could prepare the curved canals without significant shaping errors.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2000년도 7월 학술대회지
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• pp.166-177
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• 2000

The purpose of this study was to create letters for of nonliterary Pulang tribe in Thailand those who immigrant from China. illiterate Pulang tribe hand down their tradition by primary oral culture therefore their tradition can't initiate and keep, moreover, it may disappear throughout history. So it is expected to crusade against unlettered people. The scheme of research adopted in this study was a minority race who habitate at the northern Machan, Chiangrai in Thailand. It is not only analysis of language but also the eradication of literacy and the research based on linguistic, ethnolinguistic, and primary oral culture. Five Pulang people who live in that area were chosen for creating letters. By using the I. P. A., after each word was listen to their pronunciation one by one it was described and repeated this process several times; the material words and humanbody were pointed in front of them while other words were described by gesture. For final description, number of people were in the lineup for listening the sound of words and phrases to sentences. In the first stage, it was an analysis segmental of Pulang: vocoid, contoid and diphthong were described with each sample syllables and words. The suprasegmental were studied with intonation and juncture of the words in the second stage. Two words were compared and different meanings within their intonation and juncture were shown. At the end of this part, each case of phonemic or morphophonemics representation described the juncture in the words. In the third stage, minimal pairs were analyzed with vowels and consonants and described in free variation based on words. In the last stage, syllable structure in open syllable and closed syllable was studied and then each syllable of its structure was analyzed with samples. There were thirty-two phonemes in apong Pulang as follows: seven vocoids; a, i, e, o, u, ${\ae}$, and $\wedge$, one diphthong; wu, 24 contoids; b, c, d, f, g, h, j, k, k, 1, m, n, ${\eta}, {\;}p^{h}$, p, p, r, s, s, sh, t, t, w, and y. Their pronunciations of p, s, d, $p^{h}$, j, and t are frequently used in speech and are unique in triphthong. Moreover, most of the words used initial and final consonant cluster.

• Progress in Superconductivity
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• 제2권2호
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• pp.86-91
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• 2001

Temperature dependences of the unloaded Ｑ(Ｑ$_{0}$) and the resonant frequency ( $f_{0}$) of YB $a_2$C $u_3$ $O_{7-{\delta}}$ (YBCO) microstrip ring resonators and rutile-loaded cylindrical cavity resonators were measured at low temperatures. Dc magnetron-sputtered YBCO films grown on Ce $O_2$-buffered r-cut sapphire (CbS) substrates were used fur this purpose. The surface resistances ( $R_{s}$) of YBCO films measured by both a microstrip ring resonator and a TE $01\delta$/ mode rutile-loaded cylindrical cavity resonator are compared with each other. It turned out that the values of $R_{s}$ measured by the microstrip resonator technique are comparable to those by the rutile-loaded resonator technique at temperatures lower than ~50 K. However, above 50 K, the $R_{s}$ measured by the microstrip resonator technique appeared higher according to the temperature. Our results show that the current crowding effects near the edge of a microstrip resonator become more significant at temperatures near the critical temperature.emperature.e.e.e.e.e.e.

• 한국자동차공학회논문집
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• 제5권2호
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• pp.60-68
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• 1997

Rayleigh Scattering Cross Sections($\sigma$i) of various gases and the temperature distributions of premixes C3H8/O2 flame are measured by high power KrF(248nm) Exci- mer laser and ICCD camera. Results show that $\sigma$i of O2 and Propane(C3H8) gases agree well in the 5% error range, but of H2 has the more or less difference from the calcul- ated value by other groups. This is attributed to the low RS signal of H2 to Nosie level(S/N ratio). The temperature distributions of flame range out between 300K in the air and about 2000K in the burned area. In this temperature range, out system has the about 250K temperature resolution. Because low RS signals in the reaction area with high temperature are affected highly by noises, temperature uncertainty of this area is relatively high to another part of flame. Experimental results show that UV Rayleigh Scattering can be used for the measurement of mixing ratio of mixed gases and the temperature distributions of flame. Especially, this technique can be applied for the measurement of the mixing ratio of air/fuel before the ignition and the flame structure after the ignition inside the Engine.