• 대한치과보철학회지
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• 제40권2호
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• pp.140-155
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• 2002

Void-free impression taking is important for the fabrication of accurate dental restorations. One of the essential properties of an impression material used for indirect fabrication of precision castings is the reproduction of the fine detail. The objective in this study was to determine the influence of mixing methods on the number of voids and surface detail reproduction. The number of voids and surface detail reproduction were evaluated with the steteomicroscope $SZ-PT^{(R)}$ and photographed. The results were as follows ; 1. In comparison of the void formation according to mixing methods of all impression materials, mechanical mixing was better than hand mixing and there was significant difference(p<0.05) 2. In comparison of the void formation according to hand mixing of alginate impression materials($TOKUSO\;A-1{\alpha}^{(R)},\;CAVEX\;IMPRESSIONAL^{(R)},\;AROMA \;FINE\;DF\;III^{(R)}$), there was no significant difference among alginate groups. But the number of void was increased in the order of $Panasil^{(R)}\;contact,\;TOKUSO\;A-1{\alpha}^{(R)},\;Permlastic^{(R)}$ light bodied and there was significant difference (p<0.05). 3. In comparison of the void formation according to mechanical mixing of alginate impression materials($TOKUSO\;A-1{\alpha}^{(R)},\;CAVEX\;IMPRESSIONAL^{(R)},\;AROMA FINE\;DF\;III^{(R)}$), there was no significant different among alginate groups. But the number of void was decreased in order of $TOKUSO\;A-1{\alpha}^{(R)},\;Permlastic^{(R)}light\;bodied,\;Panasil^{(R)}$ contact and there was significant difference (p<0.05). 4. In comparison of the surface detail reproduction according to mixing methods of 3 types of impression materials($TOKUSO\;A-1{\alpha}^{(R)},\;Permlastic^{(R)}\;light\;bodied,\;Panasil^{(R)}\;contact$), there was no significant difference between hand mixing and mechanical mixing method 5. The surface detail reproduction was only influenced by impression materials, and produced better in order of $TOKUSO\;A-1{\alpha}^{(R)},\;Panasil^{(R)}\;contact,\;Permlastic^{(R)}$ light bodied. There was significat difference among 3 type of impression materials(p<0.05). From the above results, void formation is influenced by mixing methods and surface detail reproduction is influenced by impression materials than mixing methods. Therefore, to fabricate accurate restorations, proper impression material and mechanical mixing method are more effective and available clinically.

• 한국가축번식학회지
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• 제22권3호
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• pp.245-252
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• 1998

The three-dimensional structure of the Sertoli cell in the rat was investigated by scanning electron microscopy. Morphologically, seven types of Sertoli cell processes were evident : Shrot, flat and ramified processes are projected from the lateral side of the basal portion of Sertoli cell. Leaf-like processes are attached to the surface of spermatocytes and spermatids. Slender cord-like processes, flat and irregular shaped processes, sucker-like processes and club-like processes are observated in the middle and apical portion of seminiferous epithelium. The sheet-like processes rest upon more than one-thirds of the surface of each spermatogonium, spermatocyes and spermatids located in the proximity of the Sertoli cell. All Sertoli processes are originated from Sertoli cell column. Just before spermiation, the processes which are attached to the head of maturation spermatid are eliminated. Though the mechanism for elimination of residual body is not known, these observations segget that the Sertoli cell process are thought to have a reciprocity with the germ cells.

• Smart Structures and Systems
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• 제11권6호
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• pp.605-621
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• 2013

The paper deals with the design of a device for sound reproduction to be fixed to a supporting surface. The device is made up of two different types of acoustic actuators based on different technologies. This allows to reproduce sound in the range of frequencies from 20 Hz to 20 kHz. The generation of sound at high frequencies is demanded to a magnetostrictive actuator, while a more traditional magnetodynamics actuator is used to generate sound at low frequencies. The coupling between these two actuators leads to a device having small overall dimensions and high performance.

• 한국동물생명공학회지
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• 제38권3호
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• pp.121-130
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• 2023

Background: Coating a culture plate with molecules that aid in cell adhesion is a technique widely used to produce animal cell cultures. Extracellular matrix (ECM) is known for its efficiency in promoting adhesion, survival, and proliferation of adherent cells. Gelatin, a cost-effective type of ECM, is widely used in animal cell cultures including feeder-free embryonic stem (ES) cells. However, the optimal concentration of gelatin is a point of debate among researchers, with no studies having established the optimal gelatin concentration. Methods: In this study, we coated plastic plates with gelatin in a concentration-dependent manner and assessed Young's modulus using atomic force microscopy (AFM) to investigate the microstructure of the surface of each plastic plate. The adhesion, proliferation, and differentiation of the ESCs were compared and analyzed revealing differences in surface microstructure dependent on coating concentration. Results: According to AFM analysis, there was a clear difference in the microstructure of the surface according to the presence or absence of the gelatin coating, and it was confirmed that there was no difference at a concentration of 0.5% or more. ES cell also confirmed the difference in cell adhesion, proliferation, and differentiation according to the presence or absence of gelatin coating, and also it showed no difference over the concentration of 0.5%. Conclusions: The optimum gelatin-coating for the maintenance and differentiation of ES cells is 0.5%, and the gelatin concentration-mediated microenvironment and ES cell signaling are closely correlated.

• 한국가축번식학회지
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• 제22권1호
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• pp.19-27
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• 1998

The present study was performed to investigate the patterns of a, pp.arance of lectin in uterus of fetuses of 90 and 120 days old and neonates of Korean native goat. The carbohydrate markers were used in histochemistry for the determination of the lectin by staining of avidin-biotin-per-oxidase complex(ABC), rincinus communis agglutinin(RCA-I), ulexeuropalus communis agglutinin(UEA) and wheat germ agglutinin(WGA). 1. The effects of this study were as follows; 1. The binding reactions for Con-A were weak on the mucosal epithelium of endometrium in 90 and 120 days old fetuses, and neonates and moderate at the free surface of mucosal epithelia. 2. The binding reactions for DBA was partially moderate on the mucosal epithelium of endometrium and partially strong at the free surface of mucosal epithelia in 120 days old fetuses. In neonates, the reactions were strong on the mucosal epithelium and gland primordium of endometrium, and the secretions at the free surface showed strong reactions for DBA. But, in 90 days old fetuses, the reaction was negative. 3. The binding reactions for RCA-I were moderate on the mucosal epithelium of endometrium and at the free surface of mucosal epithelia in 90 days old fetuses. In 120 days old fetuses, the reactions were weak on the mucosal epithelium of endometrium and moderate at the free surface of mucosal epithelia. In neonates, the reactions were moderate on the mucosal epithelium of endometrium and strong at the free surface of mucosal epithelia and also strong in the uterine gland. 4. The binding reactions for UEA were negative in 90 and 120 days old fetuses and neonates. 5. In 90 days old fetuses, the binding reactions for WGA were generally weak on the mucosal epithelium of endometrium, but several epithelial cells showed moderate reaction for WGA. In 120 days old fetuses and neonates, the reactions were moderate on the mucosal epithelium and blood vessels of endometrium and strong at the free surface of mucosal epithelia.

• 제어로봇시스템학회논문지
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• 제6권6호
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• pp.514-521
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• 2000

In this study, a surface generating system with a bundle of wires, which can reproduce a certain range of surface roughness of the objects without direct machining process, is implemented. The system consists of a bundle of wires, a PZT actuator, a vertical table system actuated linearly along two perpendicular axes, and an image processing system. Through the development of the operational software for all of those subsystems by a common language(Visual C＋＋) of the implemented system, the complete process except arrangement of a bundle of wires are automated. Lastly, through the experiments of generating the flat surface of some virtual object and then of measuring the reproduced surface roughness, it is confirmed that the implemented system has excellent performance.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.137-141
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• 2003

CRTs can survive in the long run for TV applications, because of their realistic reproduction of live images. CRT technology development has to be directed towards form factor, but also attention has to be paid to the form design of sets. The CRT is the only technology allowing a doubly curved screen surface.

• Journal of Information Display
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• 제4권1호
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• pp.38-42
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• 2003

CRTs can survive in the long run for TV applications, because of their realistic reproduction of live images. CRT technology development has to be directed towards form factor, but also attention has to be paid to the form design of sets. The CRT is the only technology allowing a doubly curved screen surface.

• 암석학회지
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• 제27권4호
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• pp.207-222
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• 2018

국립고궁박물관 소장 천상열차분야지도 각석 및 복각천상열차분야지도 각석은 우리나라의 전통 천문학 수준을 실증하는 대표적인 과학문화유산이다. 태조본 각석은 암갈색 점판암, 숙종본 각석은 회백색 백운암으로 서로 다른 암석으로 제작되었다. 태조본 점판암은 석영, 백운모, 백운석의 광물조성을 보였으며, 숙종본 백운암은 백운석, 고토감람석, 방해석으로 구성되어 있다. 태조본 각석은 숙종본에 비해 손상이 심화되어 있으며 주요한 손상인자는 균열 및 탈락이다. 숙종본에서는 긁힘과 인위적인 오염물이 관찰되었다. 태조본 및 숙종본 각석 측면과 후면에 나타나는 녹색 및 흑색 표면오염물은 수지 기반의 페인트 물질로 해석된다. 한편, 초음파 물성평가에서 태조본 각석은 좌측면 상부가, 숙종본 각석은 전면 우측부가 저속도대를 보인다. 태조본각석의 안정성을 저해하는 주요 균열에 대해 To-Tc법으로 발달 상태를 조사한 결과, 균열의 전개부 및 중심부에서 가장 깊은 심도가 측정되었다.

• 한국가축번식학회지
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• 제23권4호
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• pp.347-352
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• 1999

1. 유전자 재 조합 호르몬 (eCG IPMSG, hCG 및 hFSH)의 활성체크 및 세포내 signal transduction에 관한 기초연구를 위하여 rat의 융모성 성선자극 호르몬 수용체 (LH/CGR) 및 난포 자극호르몬 수용체 (FSHR)를 이미 보고되어진 염기배열에 의하여 PCR 방법으로 크로닝 하여, human embryonic kidney 유래의 293 세포에 transfection 하여 세포 표면에 LH/CGR와 FSHR를 발현하는 cell lines을 분리하였다. 2. hCG와 FSH의 signal을 전달하는 능력은 hCG와 FSH 또는 eCG의 농도증가에 따라 이들 수용체로 하여금 세포내의 cAMP 분비가 증가함을 알 수 있었다. 즉, transfection 되어진 이들 수용체를 발현하는 수용체의 대부분은 ligand binding 기능올 가지고, cAMP 반응에 의한 생리활성을 분석할 수 있으며, 또한 유전자 재조합당 단백질 호르몬 (eCG, hCG 및 hFSH)의 signal transduction, 구조 및 기능연구에 활용할 수 있다.