• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.375-382
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• 2001

This study is attempted to predict experimentally the fatigue crack propagation behavior of two-span beams with steel fibrous for various steel fibrous contents. The static tests and the fatigue tests were performed on a series of SFRC(steel fibrous reinforced concrete) to investigate the fatigue behavior of SFRC varying with the steel fibrous contents. Through this test, the diagonal cracking loads, ultimate loads, deflections, strains of concrete and steels. Fatigue crack length were measured by the eye-observation. As a result of test, A model for S-N relationship, and propagation life of fatigue crack of SFRC was proposed. The crack growth and failure of SFRC beams were studied.

• 한국광학회지
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• 제15권4호
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• pp.375-384
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• 2004

Ti:LiNbO$_3$ 세 도파로형 광도파로와 CPW 진행파 전극으로 구성된 고속 외부 광변조기를 설계, 제작하였다. 결합모드 이론을 이용하여 세 도파로 광결합기의 스위칭 현상을 해석하였으며, 유한차분법을 이용하여 결합길이를 계산하였다. SOR에 의해 위상속도 및 특성 임피던스 정합 조건이 만족되도록 CPW 진행파 전극의 파라미터를 설계하였다. 제작된 소자의 dc 스위칭 및 전극의 RF 특성을 측정하였다. 제작된 세 도파로 광변조기의 삽입손실과 스위칭 전압은 약 4 dB와 15.6 V였다. RF 특성을 얻기 위하여 회로분석기(Network Analyzer)를 이용하여 진행파 전극의 S 파라미터를 측정하였다. 측정 결과 진행파 전극의 특성임피던스 Z$_{c}$=39.2$\Omega$, M/W(Microwave) 유효굴절률 N$_{eff}$=2.48, 그리고 감쇠상수 a$_{m}$ =0.0665/(equation omitted)등의 파라미터를 추출하였다. 추출된 진행파 전극 파라미터를 이용하여 이론적인 주파수 응답 R($\omega$)을 계산하였으며, 광 검출기로 측정된 주파수 응답 R($\omega$)과 비교하였다. 주파수 응답측정 결과, 3 dB 변조대역폭은 13 GHz로 측정되었다.

• The Journal of Asian Finance, Economics and Business
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• 제9권3호
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• pp.365-375
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• 2022

This study examines the relationship between board gender diversity and financial performance. The annual data of Palestinian nonfinancial listed enterprises from 2015 to 2019 was analyzed using a longitudinal panel analysis for the study's purposes. When conditional mean regression methodologies were used in the study, the results indicate that there is an insignificant relation between board gender diversity and firm financial performance. However, when analyzing women directors' effect on a firm's financial performance, endogeneity is always a concern, therefore, we test for endogeneity by employing the Darbin-Wu Housman test and then by using 2SLS. Nevertheless, when looking at the dispersion of a firm's performance using quantile regression, the results show that having women on the board improves financial performance slightly, especially for high-financial-performing firms. The findings indicate that there is a legal significant gap hindering the protection of gender diversity in boardrooms, and limiting the existence and representation of women in leadership positions, specifically, board of directors. The results of this study contribute to corporate governance and business culture literature by shedding the light on the importance of board gender diversity, to improve the firm financial performance, and hence, protect the interests of all shareholders' categories.

• Biomolecules & Therapeutics
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• 제2권3호
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• pp.286-291
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• 1994

The mutagenicity of DA-3030(rhG-CSF)was studied by reverse mutation test, chromosome aberration test and micronucleus test. The reverse mutatuon test in bacteria was performed using salmonella typhimurium strain TA100, TA98, TA1535 and TA1537 with rhG-CSF in any of the concentrations(150, 75, 37.5, 18.75, 9.375 and 4,6875 $\mu\textrm{g}$/plate), no increase in the number of revertant colonies in each strain was observed, irrespective of treatment with the metabolic activation system(S-9 mix) The chromosome aberration test was carried out using CHL cells, cell line from chinese hamster lung. With 4 doses(75, 37.5, 18.75 and 9.375 $\mu\textrm{g}$/ml) of rhG-/CSF the cells were treated for 24 or 48 hours in the direct method or for 6 hours followed by 18 hour-expression time in the metabolic activation method. Results of the study showed, by the direct method or metabolic activation method, no trend toward increase in the number of aberrant metaphase. The micronucleus test was carried out using ICR mice at the age of 8 weeks. Three doses(862.5, 1725 and 3450 $\mu\textrm{g}$/kg) of DA-3030 were admintstered intraperitoneally with single shot and bone marrow cells were sampled at 24 hours after administration. Neither the number of polychromatic erythrocytes with micronuclei nor the ratio of normochromatic erythrocytes to polychromatic erythrocytes increased singinficantly in each dose, compared with a vehicle control. These results indicate that rhG-CSF has not mutagenic potential under the condiions.

• Coupled systems mechanics
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• 제8권4호
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• pp.351-375
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• 2019

The present work investigates the use of a rigid rocking block as a tool to reduce vibrations in a frame structure. The study is based on a simplified model composed by a 2-DOF linear system, meant to represent a general M-DOF frame structure, coupled with a rocking rigid block through a linear visco-elastic device, which connects only the lower part of the 2-DOF system. The possibility to restrain the block directly to the ground, by means of a second visco-elastic device, is investigated as well. The dynamic response of the model under an harmonic base excitation is then analysed in order to evaluate the effectiveness of the coupling in reducing the displacements and the drift of the 2-DOF system. The nonlinear equations of motion of the coupled assemblage 2-DOF-block are obtained by a Lagrangian approach and then numerically integrated considering some reference mechanical and geometrical quantities as variable parameters. It follows an extensive parametric analysis, whose results are summarized through behaviour maps, which portray the ratio between the maximum displacements and drifts of the system, with and without the coupling with the rigid block, for several combinations of system's parameters. When the ratio of the displacements is less than unity, the coupling is considered effective. Results show that the presence of the rocking rigid block improves the dynamics of the system in large ranges of the characterizing parameters.

• 복식문화연구
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• 제9권3호
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• pp.375-388
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• 2001

This study looks into the appearances and contents of undercloths advertisements by analyzing them appeared in women\`s magazines of Korea, which are , and published between 1965 and 1999 mainly targeting the women at the age of 20s through 40s. This study leads to the following conclusions : 1. Most of advertisements use 1 or 2 pages of the magazines with colored pictures. 2. The most frequently advertised underclothes is brassieres and white and pastel are dominant colors. Also, spandex and cotton are the most frequently appeared fabrics in the advertisement. 3. Professional Korean female models in twenties are the most favored choice for those underclothes advertisements and those models dominantly face their fore part with showing the body parts higher than their knees. Solo model appear in most of the advertisements and independent appearance is dominant. 4. In the visual expression of the advertisements explicitly show the products for visual expression, whereas verbal expressions mostly emphasize the benefits to be obtained from the underclothes advertised. 5. Advertisement appeals are mainly base on readers\` reason rather than sensibility.

• 대한수의학회지
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• 제35권2호
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• pp.375-381
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• 1995

Two intraocular tumors were identified in low and medium dosed groups of a carcinogenicity study using 200 males and 200 females Sprague-Dawley rats in Screening & Toxicology Research Center, Korea Research Institute of Chemical Technology. The tumors were grossly observed as white or yellow, unilateral nodules. They were approximately $1-2{\times}3-5mm$ in size. The tumors located in the region of iris and/or ciliary body invaded peripheral cornea. The microscopic features were usually composed of spindle cells arranged in parallel, forming gently curving bundles or whorls. The spindle cells had poorly defined cell boundaries, scant to moderate cytoplasm, fusiform nuclei and indistinct nucleoli. Mitotic figures were rare and areas of necrosis were present. The spindle cells had positive immunoreactivity for S-100 protein and vimentin but negative for desmin, collagen and HMB-45 antibody. In special histochemical studies, the spindle cells react with Gomori's stain for argyrophih fibers, Prussian blue stain for iron but negative with Masson-Fontana's stain for melanin granules. Ultrastructurally, cytoplasmic premelanosomes were not observed in the tumor cells due to the poor preservation of tumor masses. Based on the results, the tumors were diagnosed as amelanotic melanoma.

• 센서학회지
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• 제31권6호
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• pp.371-375
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• 2022

Antimony-doped tin oxide (ATO) thin films, one type of transparent conductive oxide (TCO) films, were prepared on a SiO₂-coated glass substrate with different substrate temperatures by a radio-frequency magnetron sputtering system. Structural, optical, and electrical characteristics of the deposited ATO films were analyzed using X-ray diffraction, scanning electron microscopy, alpha-step, ultraviolet-visible spectrometer, and Hall effect measurement. The substrate temperature during deposition did not affect the basic crystal structure of the films but changed the grain size and film thickness. The optical transmittance of the ATO films deposited at different substrate temperatures was over 70%. The lowest sheet resistance and resistivity were 8.43 × 10² Ω/sq, and 0.3991 × 10^-2 Ω·cm, respectively, and the highest carrier concentration and mobility were 2.36 × 10²¹ cm^-3 and 6.627 × 10^-2 cm²V^-1s^-1, respectively, at a substrate temperature of 400 ℃.

• 청정기술
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• 제24권1호
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• pp.35-40
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• 2018

$N_2O$ 촉매 분해 반응을 위한 $Co_3O_4$ 촉매는 공침법을 이용하여 제조하였으며, 조촉매로서 Ce 및 Zr의 양을 (Ce 또는 Zr)/Co = 0.05의 몰비로 고정하여 제조하였다. 또한 K가 촉매에 미치는 영향을 조사하기 위해 1 wt%의 $K_2CO_3$를 함침하여 촉매를 제조하였다. 제조된 촉매의 특성은 BET, SEM, XRD, $H_2-TPR$, XPS를 통해 분석하였다. $Co_3O_4$ 촉매는 스피넬 결정상을 나타냈으며, 조촉매의 첨가는 입자 크기와 결정 크기를 감소시켜 비표면적을 증가시키는 것으로 나타났다. K의 도핑은 촉매 활성 물질인 Co의 활성 종인 $Co^{2+}$의 농도를 증가시켜 촉매 활성을 향상시키는 것으로 확인되었다. $N_2O$ 분해 반응 테스트는 $GHSV=45,000h^{-1}$, $250{\sim}375^{\circ}C$에서 수행되었으며 $Co_3O_4$ 촉매에 조촉매를 첨가하였을 때도 반응성이 증가하였지만, K를 함침하면 활성이 더욱 크게 증가하는 것으로 나타났다. K의 도핑이 활성 종인 $Co^{2+}$의 농도를 증가시키며, 환원온도를 낮춰 주어 활성에 큰 영향을 주는 것으로 확인하였다.

• 한국도서관정보학회지
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• 제39권2호
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• pp.375-405
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• 2008

최근 어린이 전용 인터넷 검색엔진이 어린이들에게 주요한 정보 접근방법이 되고 있다. 어린이 전용 검색엔진이 제대로의 기능을 발휘하기 위해서는 검색엔진을 이용한 어린이들의 탐색행태에 관한 연구들이 수행되고, 그 결과가 시스템 설계와 개선에 응용되어야 한다. 본 연구에서는 국내 대표적인 어린이 전용 검색엔진인 쥬니버와 야후꾸러기를 이용하여 초등학교 3학년 학생들의 정보탐색행태를 실험을 통해 분석하였고, 질문지와 면담을 통하여 참가자들의 개인적 특성과 시스템에 대한 인식을 측정하였다. 연구결과를 바탕으로 어린이 전용 검색엔진의 문제점을 진단하고 개선방안을 제시하였다.