• Steel and Composite Structures
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• 제33권6호
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• pp.805-822
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• 2019

In this work, a simple four-variable integral plate theory is employed for examining the thermal buckling properties of functionally graded material (FGM) sandwich plates. The proposed kinematics considers integral terms which include the effect of transverse shear deformations. Material characteristics and thermal expansion coefficient of the ceramic-metal FGM sandwich plate faces are supposed to be graded in the thickness direction according to a "simple power-law" variation in terms of the "volume fractions" of the constituents. The central layer is always homogeneous and consists of an isotropic material. The thermal loads are supposed as uniform, linear, and nonlinear temperature rises within the thickness direction. The influences of geometric ratios, gradient index, loading type, and type sandwich plate on the buckling properties are examined and discussed in detail.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.56-60
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• 2006

We review our studies on the growth of microcrystalline silicon films by the standard PECVD technique. In situ spectroscopic ellipsometry studies allow the optimization of the complex film structure with respect to competing aspects of the growth process. Fine tuning the hydrogen flux, the ion energy, and the nature of the species contributing to deposition produces unique films with a fully crystallized interface with silicon nitride. These materials have been successfully incorporated in bottom gate TFTs which present mobility values in the range of 1 to 3 $cm^2/V.s$, and stable characteristics when submitted to a bias stress. The stability of these TFTs makes them suitable for driver applications in AMLCDs as well as pixel elements in OLED displays.

• Advances in nano research
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• 제7권2호
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• pp.89-98
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• 2019

In this work, the thermal buckling characteristics of zigzag single-walled boron nitride (SWBNNT) embedded in a one-parameter elastic medium modeled as Winkler-type foundation are investigated using a nonlocal first-order shear deformation theory (NFSDT). This model can take into account the small scale effect as well as the transverse shear deformation effects of nanotubes. A closed-form solution for nondimensional critical buckling temperature is obtained in this investigation. Further the effect of nonlocal parameter, Winkler elastic foundation modulus, the ratio of the length to the diameter, the transverse shear deformation and rotary inertia on the critical buckling temperature are being investigated and discussed. The results presented in this paper can provide useful guidance for the study and design of the next generation of nanodevices that make use of the thermal buckling properties of boron nitride nanotubes.

• 국제물리치료학회지
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• 제2권1호
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• pp.244-250
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• 2011

The purpose of this study is to investigate whether there are differences in physique characteristics between the excellent domestic player groups in each sport player's, to prevent epidemiologic damage of musculoskeletal system and to provide fundamental data to improve performances for players. This study has performed for total 60 student players from Y University in Yongin, Gyeonggi-do, consists of 20 Kendo players, 20 Judo players and 20 Taekwondo players. We measured the length and circumference of arm, leg, body using Martin anthropometer to collect the data for 3 groups. There was significant difference in lower left arm length between player groups(p<.01), and Kendo players' right side femoral were longer than other 2 groups for leg length measurement(p<.01). Judo players' circumference for right/left stretched arm/bent upper arm were thicker than other 2 groups(p<.01). Taekwondo players' chest circumference were smaller than other 2 groups(p<.01), and Taekwondo players' right/left femoral circumference were thinner than other 2 groups(p<.05). From this study, it was found that there are physique characteristics differences between the Kendo, Judo and Taekwondo player groups. This indicates that repeated exercise for each sport player causes physique change, and it may cause epidemiologic damage of musculoskeletal system. It is recommended to perform balancing exercise prior to main exercise.

• Advances in nano research
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• 제7권6호
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• pp.443-457
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• 2019

In this investigation, dynamic and bending behaviors of isolated protein microtubules are analyzed. Microtubules (MTs) can be considered as bio-composite structures that are elements of the cytoskeleton in eukaryotic cells and posses considerable roles in cellular activities. They have higher mechanical characteristics such as superior flexibility and stiffness. In the modeling purpose of microtubules according to a hollow beam element, a novel single variable sinusoidal beam model is proposed with the conjunction of modified strain gradient theory. The advantage of this model is found in its new displacement field involving only one unknown as the Euler-Bernoulli beam theory, which is even less than the Timoshenko beam theory. The equations of motion are constructed by considering Hamilton's principle. The obtained results are validated by comparing them with those given based on higher shear deformation beam theory containing a higher number of variables. A parametric investigation is established to examine the impacts of shear deformation, length scale coefficient, aspect ratio and shear modulus ratio on dynamic and bending behaviors of microtubules. It is remarked that when length scale coefficients are almost identical of the outer diameter of MTs, microstructure-dependent behavior becomes more important.

• Clinical and Experimental Pediatrics
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• 제51권10호
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• pp.1052-1057
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• 2008

목 적: 초등학생들의 실제 체격 측정치와 자신의 체격에 대한 인식 및 만족도를 살펴보고, 그에 따른 자아존중감, 사회성 및 문제행동특성을 규명하고자 한다. 방 법: 서울에 소재한 초등학교 4, 5, 6학년생 465명(남학생 231명, 여학생 234명)을 대상으로 키와 체중에 대한 인식 및 만족도 조사, 자아존중감 검사(self-esteem inventory, SEI), 아동 청소년 행동평가척도(Korean Child Behavior Checklist, K-CBCL)를 실시하였다. 이들에서 신장과 체질량지수를 구하여 2007년 대한소아과학회의 신체발육표준치를 기준으로 저신장, 경계군, 정상 또는 비만, 과체중, 정상의 세 군으로 분류하였고, 키에 대한 인식도는 작은 편, 보통, 큰 편으로, 체중에 대한 인식도는 마른 편, 보통, 뚱뚱한 편으로 구분하였다. 수집된 자료는 SPSS for Windows (version 12.0, SPSS, Chicago, IL, USA)를 사용하여 chi-square test, ANOVA test등을 실시하여 분석하였다. 결과: 실측된 자신의 키와 체중에 대하여 인식 및 만족도에서 의미 있는 차이를 보였다(P<0.05). 키나 체중의 실제 측정치에 따른 자아존중감, 사회성, 행동특성의 유의한 차이는 없는 것으로 나타났다(P>0.05). 키와 체중에 대한 인식과 만족도에 따라 자아존중감에 의미 있는 차이를 보였다 (P<0.01). 결 론: 자신의 키나 체중에 대하여 정확하게 인식하고 만족하고 있는 아동들의 자아존중감이 높게 나타났다. 따라서 체격에 대한 올바른 인식확립과 교육으로 심리적 지지를 제공해야 하겠다.

• Advances in materials Research
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• 제11권1호
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• pp.1-22
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• 2022

In this paper, the nonlocal integral Timoshenko beam model is employed to study the free vibration characteristics of singled walled carbon nanotubes (SWCNTs) including the thermal effect. Based on the nonlocal continuum theory, the governing equations of motion are formulated by considering thermal effect. The influences of small scale parameter, the chirality of SWCNTs, the vibrational mode number, the aspect ratio of SWCNTs and temperature changes on the thermal vibration properties of single-walled nanotubes are examined and discussed. Results indicate significant dependence of natural frequencies on the nonlocal parameter, the temperature change, the aspect ratio and the chirality of SWCNTs. This work should be useful reference for the application and the design of nanoelectronics and nanoelectromechanical devices that make use of the thermal vibration properties of SWCNTs.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.107-108
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• 2008

The spectacular development of AMLCDs, been made possible by a-Si:H technology, still faces two major drawbacks due to the intrinsic structure of a-Si:H, namely a low mobility and most important a shift of the transfer characteristics of the TFTs when submitted to bias stress. This has lead to strong research in the crystallization of a-Si:H films by laser and furnace annealing to produce polycrystalline silicon TFTs. While these devices show improved mobility and stability, they suffer from uniformity over large areas and increased cost. In the last decade we have focused on microcrystalline silicon (${\mu}c$-Si:H) for bottom gate TFTs, which can hopefully meet all the requirements for mass production of large area AMOLED displays [1,2]. In this presentation we will focus on the transfer of a deposition process based on the use of $SiF_4$-Ar-$H_2$ mixtures from a small area research laboratory reactor into an industrial gen 1 AKT reactor. We will first discuss on the optimization of the process conditions leading to fully crystallized films without any amorphous incubation layer, suitable for bottom gate TFTS, as well as on the use of plasma diagnostics to increase the deposition rate up to 0.5 nm/s [3]. The use of silicon nanocrystals appears as an elegant way to circumvent the opposite requirements of a high deposition rate and a fully crystallized interface [4]. The optimized process conditions are transferred to large area substrates in an industrial environment, on which some process adjustment was required to reproduce the material properties achieved in the laboratory scale reactor. For optimized process conditions, the homogeneity of the optical and electronic properties of the ${\mu}c$-Si:H films deposited on $300{\times}400\;mm$ substrates was checked by a set of complementary techniques. Spectroscopic ellipsometry, Raman spectroscopy, dark conductivity, time resolved microwave conductivity and hydrogen evolution measurements allowed demonstrating an excellent homogeneity in the structure and transport properties of the films. On the basis of these results, optimized process conditions were applied to TFTs, for which both bottom gate and top gate structures were studied aiming to achieve characteristics suitable for driving AMOLED displays. Results on the homogeneity of the TFT characteristics over the large area substrates and stability will be presented, as well as their application as a backplane for an AMOLED display.

• 대한화학회지
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• 제54권1호
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• pp.110-114
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• 2010

알제리에서 출토되는 소듐-교환된 Maghnia 점에 대한 2개 염기성 염료인 RB5와 BG4의 흡착평형을 조사한 결과, 최대 흡착능은 각기 465.13 와 469.90 mg/g 으로 나타났다. ADMI 방법을 사용한 BR5 and BG4의 동시 흡착 실험에서 3개 다른 초기 농도비R (R=$C_{(BR5)}/C_{(BG4)}$) 2.5/1, 1/1, 1/2.5 을 사용하였다. 염료혼합물로부터 등온흡착 여부를 조사하여 경쟁 흡착인지를 알수 있다. 점토 표면 위 흡착 활성자리를 위한 BR5 and BG4 간 매우 강한 상호작용(R = 1/1)이 관찰되었다. RB 5 와 BG 4의 흡착능의 비율 R' (R'=$Qe_{(mixture)}/Qe_{(single)}$)은 초기 농도 비율 R (R=$C_{(BR5)}/C_{(BG4)}$)이 2.5/1, 1/1 and 1/2.5 인 경우에 대해 각기 0.86, 0.74 and 0.84 로 얻어졌다. Langmuir 와 Freundlich 모델이 각기 염료 뿐만 아니라 염료 혼합물의 흡착 거동에 잘 들어 맞음을 알 수 있었다.

• 사상체질의학회지
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• 제2권1호
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• pp.71-85
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• 1990

673 third-year students of boy's and girl's high schools in Taegu city and Kuni-gun and Youngyang-gun and Euisung-gun in Kyongbuk province were selected and investigated as the subject, of this study on the correlation between Lee Jae Ma's Four Types of Essential Physical Constitution and Physical Form index. The result of the study was found as follows. First, as for Height, the findings were not identical with the expression that "person of shaoyin(minor Yin) Type are short and small -- while person of Taiyin (major Yin) Type are tall and big," cited in classification of four different constitutions in a document named "Dong-Eu-Su-Se-Bo-Won". Comparison of persons of Shaoyang (minor Yang) - Type proved infitness due to the lack of data on Height in documents concerning Lee Jae Ma's four types of essential physical constitution. Second, as for Sitting Height, the correlation was prored between the findings of this study and the expression in the above document describing external physical characteristics of shaoyin-Type persons that "The upper part and' the lower part of the body are well balanced", but in point of Relative Sitting Height, none between the two. Third, as for Chest-Girth and Relative Chest-Girth plus Weight and Relative Weight, the expression that "Persons of Taiyin(major Yin) Type have the largest physique of the lour types of persons in the characteristics of external physical features, and that they also tend to have continental(widechest or large-scaled) character and strong nerve, that they are stoutly-built and fal." proved to have the correlation with the findings of this study. Fourth, in point of Chest-Girth and Relative Chest-Girth, this study found that its findings have the correlation with the phrase that "Chests are well developed upwar -- and sturdy and solid." in describing the characteristics of Shaoyang (minor Yang)-Type person' external physical features, and that with the phrase that "Chests are narrow" in the case of Shaoyin(minor Yin)-Type persons. Fifth, as for Weight and Relative Weight, the correlation was found between the findings and the expression that "shaoyin-Type persons have comparatively less flesh" as a sign of external physical characteristics of Shaoyin-Type persons. The above-cited findings proved that there exist some correlations between external physique of the Lee Jae Ma's four types of essential constitution and physical Form Indexes. Actually, however, in clinical classification, it is desirable that this approach should be consulted only after carefull consideration based on Lee Jae Ma's theory, and it seems imperative to continue the study of objectivization of Lee's theory.