• Elastomers and Composites
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• v.27 no.4
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• pp.267-274
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• 1992

Polydimethylsiloxane(PDMS)-containing polyurethane coating materials were synthesized because PDMS-based elastomers have unique properties including an extremely low glass transition temperature, good thermal and oxidative stability, and good dielectric properties. In this experiment a vinyl copolymer which consisted of vinyl chloride, vinyl acetate, vinyl alcohol, and maleic acid was used, and Coronate L was used as a polyisocyanate. PDMS-containing polyurethane was synthesized from polydimethylsiloxane, MDI, and 1,4-butanediol. Films were casted by reaction of viny copolymer, Coronate L, and PDMS-containing polyurethane. Thickness of tile films were $150-170{\mu}m$ and the films were characterized by IR, DSC, and Instron.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1555-1557
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• 2002

We have investigated the precharge type sense amplifier, it is suitable fur voltage sensing in a NOR type single transistor ferroelectric field effect transistor (1T FeFET) memory read operation. The proposed precharge type sense amplifier senses the bit line voltage of 1T FeFET memory. Therefore, the reference celt is not necessary compared to current sensing in 1T FeFET memory, The high noise margin is wider than the low noise margin in the first inverter because requires tile output of precharge type sense amplifier high sensitivity to transition of input signal. The precharge type sense amplifier has very simple structure and can sense the bit line signal of the 1T FeFET memory cell at low voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.52-55
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• 1997

In this study, PLZT stock solutions were prepared by sol-gel processing to fabricate PLZT thin films. The stock solutions were spin-coated on ITO-glass and the film were annealed by rapid thermal annealing(RTA). The variation of tile crystallographic structure of the thin films and the phase transition with respect to it were observed using Raman spectra. Raman result showed that the band of spectra are broad as the amount of Zr substitution increased and specially, abrupt change occurs in the raman spectra upon crossing the tetragonal-rhombohedral phase boundry at 2/55/45 PLZT thin film. So, the fact that the crystallographic structure was transitted from tetragonal to rhombohedral structure was certified.

• The Mathematical Education
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• v.29 no.1
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• pp.55-61
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• 1990

There are three objectives of this paper. First, we present an elegant and simple generalization of Abel's theorem (i .e. tile Abel summability (on the unit disk of the euclidean plane) is regular). Second, we consider the definition of Abel summability through lim (equation omitted) which immediately has clear connexctions with CeSARO summability and Cesaro sums (equation omitted). This approach examplifies some simple aspects of so-called Tauberian theorems of divergent series. Third, we present the applications of the previous results to find the limits of transition probabilities of homogeneous Marker chain. Finally, we explain why the original Abel's theorem which looks obvious is difficult to be proved, and can not be proved analytically.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.213.1-213.1
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• 2015

Field effect transistors (FETs)를 기반으로 한 바이오센서는 빠른 응답속도, 저비용, label-free 등을 이유로 각광받고 있다. 그러나 3D 구조를 기반으로 한 FETs 바이오센서의 낮은 sensitivity의 한계점을 지니며, 이를 극복하기 위해 1D 구조의 나노튜브 등을 활용하였으나 여전히 높은 sensitivity의 확보는 힘들다. 최근에는 이러한 문제점을 극복하기 위해 이차원 반도체 물질 중 하나인 Transition metal dichalcogenide (TMD)를 이용하여, 700 이상의 sensitivity를 지니는 pH센서 및 100 이상의 sensitivity를 지니는 바이오센서가 보고되었다. 하지만 이보다 더 높은 정확성 및 반응성을 높이기 위한 연구는 부족한 실정이다. 우리는 DNA 템플릿을 이용하여, TMD FET 기반 pH 및 바이오센서의 반응성을 극대화시키는 연구를 선보인다. DNA는 7~8정도의 유전상수 (K)를 가지는 물질로 기존 $SiO_2$(K=3.9)보다 높은 유전상수를 가지며 두께를 0.7 nm로 매우 얇게 형성할 수 있는 장점이 있다. 이는 FET 기반 바이오센서의 표면 캐패시턴스를 높여 sensitivity를 극대화할 수 있으며, 기존에 사용된 high-k 기반 바이오센서와 비교하여도 약 10배 이상의 sensitivity 향상을 노릴 수 있다. 또한, TMD 물질로 우리는 $WSe_2$를 선택하였으며, pH 용액의 receptor로써 우리는 3-Aminopropyltriethoxysilane (APTES)를 활용하였고, 템플릿으로 사용된 DNA는 DX tile 및 Ring type의 두 가지를 사용하였다. 추가로, DNA의 phosphate backbone을 중성화시키고 DNA의 base pairing의 charge 안정화를 위해 구리 이온($Cu^{2+}$) 및 란타넘족($Tb^{3+}$)을 추가하였다. 완성된 바이오센서의 pH 센싱을 위해 우리는 pH 6,7,8의 표준 용액을 사용하였으며, 재현성 및 반복성의 확인하였다.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.4
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• pp.24-32
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• 2007

In this study, computational structural vibration analyses of a smart unmanned aerial vehicle (SUAV) with tilt-rotors due to dynamic hub loads have been conducted considering detailed supporting structures of installed equipments. Three-dimensional dynamic finite element model has been constructed for different fuel conditions and tilting angles corresponding to helicopter, transition and airplane flight modes. Practical computational procedure for modal transient response analysis is successfully established. Also, dynamic loads generated by rotating blades and wakes in the transient and forward flight conditions are calculated by unsteady computational fluid dynamics technique with sliding mesh concept. As the results of present study, transient structural displacements and accelerations of the vibration sensitive equipments are presented in detail. In addition, vibration characteristics of structures and installed equipments of which safe operation is normally limited by the vibration environment specifications are physically investigated for different flight conditions.

• Journal of the Korean housing association
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• v.4 no.1
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• pp.17-27
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• 1993

The Japanese-style houses built in the colonial age have changed through extension or remodeling since Koreans started residence after the liberation of the country. The objective of this study is to find out the influene of the cultural differences of the two nations on the living-style of the two nations from the comparative living-style viewpoint. 26 Japaneses-style houses built in the Ulsan city from the Open-Port year to 1945 were studied with the field survey method. The qualitative and the quantatative analysis were used. The results of this study are as follows. 1) Because of new materials and conveniences, kitchen, bathroom and toilet have changed into standing-type kitchen, bathroom and bathtub of cement and tile, and flush toilet respectively. The indoor toilets were removed and outdoor ones replaced them instead. 2) In the residential space the Koreans have altered the Dadami-room to the Ondol-room becaus of their own heating wywtem, installed glass or wooden doors for the seperation of rooms, enlarged the indoor space throuh removing walls, and developed new uasge of the Dokonoma space. The room of Zasici is most frequently used as the Korean-style Anbang. The wide space called 'living room' or 'maru' near the entrance hall. In conclusion, the guest-oriented Zasiki-style plan of the Japanese-style houses has remodeled into the family oriented Anbang-style plan.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.727-732
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• 2002

This study is to develop the model of alignment optimization based on design criteria by approaching through alignment of railway design and problems in economy, environment and technology for satisfying traffic volume of the main roads caused by economical and social developments. Now, Geographic Information System isn't applied when designing a present railway in home. And the design of railway alignment is still set on importance of transition curves and cant according to passenger comfort in abroad so tile study of railway alignment is at initiation phase so far. This paper is about decision of optimal alignment between two stations such as starting point and ending point automatically using GIS in optimization of railway alignment. A route between Sungsan city and Shinpung city is the training area and the study compared and evaluated optimal railway route by GIS automatically with present railway route designed. Present optimal fomulas was used in this study for optimization of railway alignment. The model of optimization of railway alignment was developed through topographical elements and it was mentioned by the model of road alignment because of the similarity in design of alignment. But the design of lateral track irregularities, cant fur passenger comfort and motion sickness fellowed by train rolling have to be considered more. Anyway, this study farmed the basis of using GIS and the study should be keep going on in the future.

• 보존과학연구
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• s.35
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• pp.57-71
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• 2014

As results of this study about the restoration and production techniques of the ridge-end roof tiles excavated from middle gate site in Bunhwangsa Temple, the ridge-end tile was considered that can be combined with four distinguished parts such as a body with upper and lower portions, a back, a belly, and a wing. And also some patterns can be verified. The body and the wing were piled up the coil clay and the back-side was bonded. The pileup process was assumed that three types of wood tools were applied to bond the facing surfaces. After the completion of the pileup process, the entire exterior was retouched by hand. For touching the inside, bare hands or some tools like a wooden branches were used to scratch and to re-face a clay plasterwork. And also, the stamped patterns which produced by framework were bonded to the body. The results from the XRD and the TG-DTA, Tridymite which shows the phase transition in more than $867^{\circ}C$ could not be identified, and also the endothermic reaction peak at $1063^{\circ}C$ showed the result that the alkali feldspar such as the albite was changed into a different mineral at $1050^{\circ}C$. Therefore, the ridge-end tiles can be considered that the firing temperature was below $867^{\circ}C$.

• Korean Journal of Veterinary Research
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• v.1 no.1
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• pp.54-60
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• 1961

For the purpose of investigating seasonal changes of germinal centers of splenic lymph nodules and of blood lymphocytes of ducks, the spleens of 8 ducks from a flock were observed histologically every season; 2 cases in spring (March and April), 2 in summer (July and August), 2 in autumn (October and November) and 2 in winter (December and January). Blood cells of 8 ducks from the same flock also were counted during the summer (from July to August) and autumn (from October to November) The results obtained were summarized as follows: 1. There were seasonal changes in the germinal centers of lymph nodules, that is, the germinal centers were formed in spring and disappeared in autumn. In summer these were at the stage of transition from formation in spring to disappearance in autumn. In winter, on tile other hand. the process was reversed from the stage of disappearance in autumn to the stage of formation in spring. 2. The germinal center of splenic lymph nodule was encapsulated with a fibrous capsule which disappeared concommitantly with its germinal center. 3. The percentage and absolute value of lymphocytes in autumn were higher than those in summer, the fact that seemed to be not in agreement with Flemming's view that the lymphocytic clear germinal center may be functionally at the stage of lymphocyte formation, but in agreement with Maximow's view that the large lymphocytic clear germinal center is functionally at the stage of resting and medium-sized lymphocytic germinal center may be functionally at the stage of lympocyte formatiom.