• Journal of the Korean Wood Science and Technology
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• 제46권4호
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• pp.393-401
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• 2018

Natural fibers derived from lignocellulosic materials are considered to be more environment-friendly than petroleum-based synthetic fibers. Several natural fibers, such as seedpod fibers, have a potential for development, including kapok and balsa fibers. The characteristics of both fibers were evaluated to determine their suitability for specific valuable applications. The purpose of this study was to analyze some important fundamental properties of kapok and balsa fibers, including their dimensions, morphology, chemical components, and wettability. The results showed that the average fiber lengths for kapok and balsa were 1.63 and 1.30 cm, respectively. Kapok and balsa fibers had thin cell walls and large lumens filled with air. The kapok fiber was composed of 38.09% ${\alpha}-cellulose$, 14.09% lignin, and 2.34% wax content, whereas the balsa fiber was composed 44.62% ${\alpha}-cellulose$, 16.60% lignin, and 2.29% wax content. The characteristics of kapok and balsa fibers were examined by X-ray diffraction, Fourier-transform infrared spectroscopy and differential scanning calorimetry analyses. The contact angle of the distilled water on kapok and balsa fibers was more than $90^{\circ}$, indicating that both fibers are hydrophobic with low wettability properties because of to the presence of wax on the fiber surface.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1439-1444
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• 2005

Induction motors are the most commonly used electrical drives because they are rugged, mechanically simple, adaptable to widely different operating conditions, and simple to control. The most common faults in squirrel-cage induction motors are bearing, stator and rotor faults. Surveys conducted by the IEEE and EPRI show that the most common fault in induction motor is bearing failure (${\sim}$40% of failure). Thence, this paper addresses experimental results for diagnosing faults with different rolling element bearing damage via motor current spectral analysis. Rolling element bearings generally consist of two rings, an inner and outer, between which a set of balls or rollers rotate in raceways. We set the experimental test bed to detect the rolling-element bearing misalignment of 3 type induction motors with normal condition bearing system, shaft deflection system by external force and a hole drilled through the outer race of the shaft end bearing of the four pole test motor. This paper takes the initial step of investigating the efficacy of current monitoring for bearing fault detection by incipient bearing failure. The failure modes are reviewed and the characteristics of bearing frequency associated with the physical construction of the bearings are defined. The effects on the stator current spectrum are described and related frequencies are also determined. This is an important result in the formulation of a fault detection scheme that monitors the stator currents. We utilized the FFT, Wavelet analysis and averaging signal pattern by inner product tool to analyze stator current components. The test results clearly illustrate that the stator signature can be used to identify the presence of a bearing fault.

• 대한간호학회지
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• 제28권4호
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• pp.908-919
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• 1998

The purpose of this study was to get some basic data for health care for working women, especially or hospital nurses. The number of subjects was 796 nurses from one general hospital and four private educational hospitals. The data were collected from February to April, 1988 using the questionnaire "Symptom Table on Fatigue Perception" designed by the Research Committee of Industrial Fatigue in Hygienic Association of Japan Industry. The collected data were analyzed using means and standard deviations for the subjective symptoms of fatigue and each item as an independent variable was analyzed by T-test and ANOVA test. The results are as follows 1) The mean score for degree of fatigue was 1.89 and the degree of fatigue for physical symptoms had highest score of 2.04, the next was psychological symptoms at 1.89, and neuro -sensory symptoms were the lowest at 1.74. Among the fatigue symptoms, the item scored most frequently was "Legs feel heavy" with a mean score of 2.40 and the least frequent item was "My hand and foot trembled" with a mean score of 1.40. 2) With the respect to the general characteristics of subjects, there were statistically significant difference according to age (F=17.039, p=.000), state of marriage(t=5.381, p=.000) presence of children(t=5.134, p=.000), clinical experience (F=16.663, p= .000), present position(F=18.204, p=.000), working place(F=12.598, p=.000), duty time(F=9.068, p=.000), monthly wages(F=7.361, p=.000). satisfaction about the pay and treatment at work(t=-5.511, p=.000), relation the doctors(t=-4.593, p=.000) the doctors(t=-4.593, p=.000)

• 디지털콘텐츠학회 논문지
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• 제18권1호
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• pp.1-7
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• 2017

요즘은 다향한 IT 기술의 융합을 통해 구현되는 가상현실 기술은 사용자의 체험영역을 확대하고 물리적인 에너지와 각종 비용을 절감하는 기술로 주목을 받고 있다. 본 연구에서는 가상현실 기술을 활용한 가상훈련시스템의 몰입감과 상호작용 제공을 통한 학습효과가 높은 분야를 대상으로 연구하고자 한다. 가상현실 시스템의 국내외 현황에 대해 알아보고 국내 가상훈련 시스템의 수요를 분석하여 나아가야 할 발전 방향에 대해서 연구하고자 한다. 가상현실 기기들의 사용현황에 대해서 가상훈련수요를 고려한 사업의 로드맵을 구축하고자 한다.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2737-2742
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• 2011

Ring-opening metathesis polymerization (ROMP) of an ethyl-substituted tetracyclododecene (8-ethyltetracyclo[$4.4.0.1^{2,5}.1^{7,10}$] dodec-3-ene, Et-TCD) was carried out in the presence of a ternary catalyst system consisting of $WCl_6$, triisobutyl aluminium (iso$Bu_3Al$), and ethanol. The optimal molar ratio of Et-TCD/$WCl_3$/iso-$Bu_3Al$/ethanol was found as 500/1/3/2 at which the yield of ring-opened polymer was 100%. 1-Hexene was shown to be an effective molecular weight controlling agent for ROMP reaction of Et-TCD. The hydrogenation of the ring opened polymer (p-Et-TCD) was conducted successfully using Pd(5 wt %)/${\gamma}$-$Al_2O_3$ at $80^{\circ}C$ for 1 h. Chemical structures of p-Et-TCD and its hydrogenated product($H_2$-p-Et-TCD) were characterized using 2D NMR techniques ($^1H-^1H$ COSY and $^1H-^{13}C$ HSQC). The changes of physical properties such as thermal stability, glass transition temperature and light transmittance after the hydrogenation were also investigated using TGA, DSC, and UV.

• 한국주거학회논문집
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• 제25권1호
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• pp.41-50
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• 2014

Architectural & Interior design communication is a process of exchanging information between architects and other professionals, clients, and prospectus users, and a design medium is a means of communication. Using non-immersive, conventional media, it is challenging for architects communicate physical details and users' activities in not yet built three-dimensional buildings to others. Recent advances online, Multi-User Virtual Environments (MUVEs) allow architects and other professionals to experience a virtually constructed building together using anthropomorphic avatars. In addition, MUVEs also enable them to be aware of the presence and activity of each other. Previous studies suggest that the aforementioned characteristics of MUVEs may facilitate communication between architects and others. But these are focused on communication in controlled experimental conditions. This paper discusses the ways in which MUVEs are applied for authentic and long-term collaboration, design studio, and cultural heritage reconstruction projects, produced by digital design group at the UC Berkeley and the Technion-Israel Institute of Technology, and analyzes the influences of MUVEs on those projects. MUVEs helped more precise communication between architects, electronic engineers, and medical staffs, who are collaborating for developing pioneering technology for hospitals. In design studios, MUVEs allowed students to experience other students' design outputs, and thus helped them share ideas mutually. In addition, in cultural heritage reconstruction projects, MUVEs were used for communicating with historians and residents in order to collect evidence. Based on this study, we propose that MUVEs have strong potential for enhancing the communication between architects and other professionals.

• Tuberculosis and Respiratory Diseases
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• 제59권6호
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• pp.696-699
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• 2005

SPM은 기저질환이나 외상의 과거력 없이 종격동에 기포가 생기는 질환으로 주로 젊은 연령에서 발생하며, 재발은 세계적으로 소수의 증례보고 위주로 되어 있다. 저자들은 특별한 유발 요인 없는 젊은 여자환자에서 27개월 간격으로 재발한 SPM를 경험하였고, 이는 국내에 보고된 바 없으며, 문헌고찰과 함께 보고하는 바이다.

• Carbon letters
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• 제3권1호
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• pp.1-5
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• 2002

The regional bio-wastes available in abundance in India were converted into porous carbon by heat treatment at different temperatures from $650-950^{\circ}C$. The wood retain shapes after pyrolysis though shrinkage occured both in axial and radial directions. The shrinkage in radial direction was found to be more than in axial direction in all woods. The density of woods and chars from these at a given temperature has been found to follow linear relationship. Chars were steam activated at temperature $700-800^{\circ}C$ for different times between 45-240 min. Both the temperature and time of activation with steam has a profound effect on surface area. Chars from softwoods like bagasse and castor oil plant were activated at lower temperature, i.e. $700-750^{\circ}C$ whereas hard wood chars have to be activated at higher temperature around $800^{\circ}C$. The morphology of wood as well as of chars has been studied by SEM. The comparison of the two showed that the nature of porosity in chars depends on precursor morphology, nature and physical state of wood and presence of inorganic compounds in the wood. Hard wood results in cross inter connected pores while softwood leads to fibriller structure. The present studies show that activated carbon with reasonably good surface area (${\sim}1000m^2/gm$) can be prepared from soft wood bio-wastes like bagasse and castor oil plant, while surface area ${\sim}1370m^2/gm$ was achieved from hard wood bio waste of pine wood.

• Journal of the Korean Data and Information Science Society
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• 제27권3호
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• pp.773-789
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• 2016

본 연구는 노인요양병원 입원노인의 수면양상 및 영향요인을 파악하여 이들의 수면의 질 향상을 위한 중재프로그램 개발 시 기초자료로 활용하고자 시도된 서술적 조사연구이다. G시 노인요양병원에 입원한 65세 이상의 노인환자 142명을 대상으로 구조화된 설문지와 24시간 수면기록지를 사용하여 자료 수집하였다. 요양병원 입원노인의 일일 평균 수면시간은 10.7시간이었으며 낮 수면시간은 평균 3.9시간, 밤 수면시간은 평균 6.8시간 이었다. 총 수면규칙성은 71.7%였고, 낮 수면규칙성은 평균 58.1%, 밤 수면규칙성은 평균 80.5%였다. 요양병원 입원노인의 수면시간에 영향을 주는 예측요인은 병실 내 치매환자 유무로 10.3%의 설명력을 나타냈고, 수면 규칙성에 영향을 미치는 예측요인은 통증, 병실 내 치매환자 유무, 신체기능으로 16.1%의 설명력을 나타냈다. 따라서 요양병원 입원노인의 수면양상에 영향을 미치는 추가요인 규명을 위한 후속 연구의 필요성과, 본 연구에서 확인된 요양병원 입원노인의 수면에 영향을 미치는 요인을 고려한 중재프로그램 개발 및 적용이 필요하다.

• 천문학회보
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• 제42권2호
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• pp.87.2-87.2
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• 2017

RR~Telescopii is a symbiotic nova exhibiting accretion activities through gravitational capture of the slow stellar wind from a Mira variable. We present high resolution spectra of RR~Tel obtained with MIKE and the 6.5 m Magellan-Clay telescope, in which we find broad features with FWHM exceeding $10{\AA}$ at 6545, 6825, 7082, 7023 and $7053{\AA}$. They are formed through Raman-scattering with atomic hydrogen of far-UV He II 1025, O~VI 1032, $1038{\AA}$ and C II 1036 and $1037{\AA}$. We compute the Raman conversion efficiencies using the case B recombination theory for He II emissions, which are used in turn to infer the intrinsic line luminosities of O VI and C II. The Raman O~VI features are characterized by double-peaked profiles with a peak separation ~ 60km/s, pointing out the presence of an accretion disk with a physical size of ~ sub AU. In contrast, Raman C II features exhibit profiles with a simple peak and a narrower width ~40 km/s, indicating that C II is formed in a much more extended region. The weak C II multiplet at 1335, $1336{\AA}$ found in the IUE spectral archive and the absence of C II 1036, $1037{\AA}$ in the FUSE archive show that far-UV C II lines suffer heavy interstellar extinction consistent with the distance of ~ 2.5 kpc to RR Tel.