• Title/Summary/Keyword: Material thickness

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Study on electric conduction mechanism of organic light-emitting diodes (유기 발광 소자의 전기 전도 기구 연구)

  • Chung, Dong-Hoe;Kim, Sang-Keol;Jeong, Joon;Jang, Kyung-Uk;Hong, Jin-Woong;Lee, Joon-Ung;Kim, Tae-Wan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.1007-1010
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    • 2003
  • We made use of $Alq_3$ which is the representative light-emitting material. Electric conduction mechanism and luminance characteristics were analyzed in this paper. We have also measured current density-thickness-voltage characteristics with thickness variation from 60 to 400nm. we analyzed the low electric and the high electric field in theoretically. Also, maximum luminous efficiency is the thickness 200 nm of $Alq_3$ in luminous-thickness characteristics.

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Voltage Gain Characteristics of Piezoelectric Transformer Operation in Second Thickness Extensional Vibration Mode (2차 두께방향 지동모드로 동작되는 압전트랜스포머의 Voltage Gain 특성)

  • 김성진;이수호;류주현;임인호;홍재일
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.10
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    • pp.855-860
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    • 1998
  • This paper presents a new structure for a piezoelectric transformer, operating in thickness extensional vibration mode. Modified $PbTiO_3$ family ceramics were used for the piezoelectric transformer, because it was a material with large anisotropy between elecromechanical coupling factors $K_t$ and $K_p$ . The size of piezoelectric transformer was 20mn long, 20mm wide and 3.1mm thick. The second harmonic resonant frequency of thickness extensional vibration mode was 0.72MHz at loading resistance 100[$\omega$], And Voltage gin of piezoelectric ceramics showed 0.53 at resonant frequency of sencond thickness extensional vibration mode.

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EL Properties of the Organic Light-Emitting-Diode with various Thickness and Cathode Electrode (유기발광소자의 막두께 및 음극전극의 변호에 따른 발광특성)

  • 김형권;이덕출
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.10
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    • pp.897-902
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    • 1998
  • We prepared Organic LED with a two layer structure by vacuum evaporation. The diode consisted of hole transfer layer (thickness of 30, 50, 70 nm) and electron transfer layer (thickness of 70, 50, 30 nm) material, which was N, N'-diphenyl- N, N'-bis-(3-methyl phenyl)-1,1'-diphenyl-4,4'-diamine)(TPD) and tris(8-hydroxy quinoline) aluminum(Alq3), respectively. We investigated EL properties of the LED with various thickness and cathode electrode. The best results were obtained when thickness of the electron layer is equal to that of emission layer and when AlLi alloy was used as a cathode. The EL intensity, luminance and efficiency of organic LED with equal of layer thick were improved seven, three and two times, respectively. Alq3 was ionized by carrier injection from cathode and could produce exitons. After electron-hole pairs were formed by combination of the electrons and holes at the emission layer, Alq3 layer emitted light.

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Thermal buckling of FGM beams having parabolic thickness variation and temperature dependent materials

  • Arioui, Othman;Belakhdar, Khalil;Kaci, Abdelhakim;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.27 no.6
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    • pp.777-788
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    • 2018
  • An investigation on the thermal buckling resistance of simply supported FGM beams having parabolic-concave thickness variation and temperature dependent material properties is presented in this paper. An analytical formulation based on the first order beam theory is derived and the governing differential equation of thermal stability is solved numerically using finite difference method. a function of thickness variation is introduced which controls the parabolic variation intensity of the beam thickness without changing its original material volume. The results showed the high importance of taking into account the temperature-dependent material properties in the thermal buckling analysis of such critical beam sections. Different Influencing parametric on the thermal stability are studied which may help in design guidelines of such complex structures.

Use of Pine (Pinus densiflora) Pollen Cones as an Environmentally Friendly Sound-Absorbing Material

  • JANG, Eun-Suk
    • Journal of the Korean Wood Science and Technology
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    • v.50 no.3
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    • pp.186-192
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    • 2022
  • This study examined the utility of pine (Pinus densiflora) pollen cones as an environmentally friendly material with sound-absorbing properties. Pine pollen cone samples with widths of 0.8-1.2 cm and lengths of 3.5-4.5 cm were prepared. After filling impedance tubes to heights of 6, 8, 10, or 12 cm with the pine pollen cones, the sound absorption coefficient of the pine pollen cones was investigated. The peak sound absorption frequency of the samples with a thickness of 6 cm was reached at 1,512 Hz; however, this value shifted to 740 Hz in samples with a thickness of 12 cm. Therefore, the sound-absorbing performance of pine pollen cones at low frequencies improved as the material thickness increased. According to KS F 3503 (Korean Standards Association), the sound absorption grade of pine pollen cones ranges from 0.3 to 0.5 M, depending on the material thickness of the pine pollen cones. In conclusion, the pine pollen cones demonstrated good sound absorption properties. They, thus, may be considered an environmentally friendly sound-absorbing material.

Creep analysis of plates made of functionally graded Al-SiC material subjected to thermomechanical loading

  • Majid Amiri;Abbas Loghman;Mohammad Arefi
    • Advances in concrete construction
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    • v.15 no.2
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    • pp.115-126
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    • 2023
  • This paper investigates creep analysis of a plate made of Al-SiC functionally graded material using Mendelson's method of successive elastic solution. All mechanical and thermal material properties, except Poisson's ratio, are assumed to be variable along the thickness direction based on the volume fraction of reinforcement and thickness. First, the basic relations of the plate are derived using the Love-Kirchhoff plate theory. The solution of governing equations yields an elastic solution to start creep analysis. The creep behavior is demonstrated through Norton's equation based on Pandey's experimental results extracted for Al-SiC functionally graded material. A linear variation is assumed for temperature distribution along the thickness direction. The creep strain, as well as the thermal strain, are included in the governing equations derived from classical plate theory for mechanical strain. A successive elastic solution based on Mendelson's method is employed to derive the history of stresses, strains, and displacements over a long time. History of stresses and deformations are obtained over a long time to predict damage to the plate because of various loadings, and material composition along the thickness and planar directions.

Effect of the Shoulder Pad on Arm Movement -In the Area of Functionality and Sensory (팔동작에 미치는 어깨패드의 영향에 관하여 -심미성과 기능성을 중심으로-)

  • 이은정
    • The Research Journal of the Costume Culture
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    • v.6 no.2
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    • pp.66-76
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    • 1998
  • In order to investigate the effect of shoulder pad affecting the arm movement, eleven women volunteers of standard body whose age is from eighteen to twenty-four(x±1σ) were chosen and this experiment had done according to front-vertical motion, side-vertical motion and horizontal motion of upper limps for tow different materials of shoulder pad(sponge, non-woven) and four different thickness of shoulder pad(0.6cm, 0.8cm, 1.2cm). On the base of this, this study, when putting on shoulder pad, try to find the reform method of shoulder part pattern. The results are as follows. 1. When puting on shoulder pad to blouse pattern to rise shoulder pad for rate of two-third per thickness is seemingly the best for sensory evaluation. So, when putting on shoulder pad, we understand that in order to improve sensory evaluation. So, when putting on shoulder pad, we understand that in order to improve sensory evaluation of clothes, when that, rising shoulder pad for ate of two-third per thickness is the best. 2. From the results of measure of functional volume and physiological value for functionality evaluation according to thickness and material, motion of shoulder pad, 1.2 cm thickness and non-woven material is evaluated the worst for functionality. 3. From the results of sensory evaluation and functionality evaluation of material of shoulder pad, sponge material is superior for functionality but not for sensory evaluation, non-woven material is superior for sensory evaluation non-woven material is superior for sensory evaluation but not for functionality. So, think that it had better use sponge material for functional clothes, non-woven material for aesthetical clothes. 4. From the results of functionality of clothes, when putting on shoulder pad, the worst discomfortable parts are the armpit part and the shawl part, functionality of these part shoulder be reformed.

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Nonlinear cylindrical bending analysis of E-FGM plates with variable thickness

  • Kaci, Abdelhakim;Belakhdar, Khalil;Tounsi, Abdelouahed;Bedia, El Abbes Adda
    • Steel and Composite Structures
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    • v.16 no.4
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    • pp.339-356
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    • 2014
  • This paper presents a study of the nonlinear cylindrical bending of an exponential functionally graded plate (simply called E-FG) with variable thickness. The plate is subjected to uniform pressure loading and his geometric nonlinearity is introduced in the strain-displacement equations based on Von-Karman assumptions. The material properties of functionally graded plates, except the Poisson's ratio, are assumed to vary continuously through the thickness of the plate in accordance with the exponential law distribution; and the solution is obtained using Hamilton's principle for constant plate thickness. In order to analyze functionally graded plate with variable thickness, a numerical solution using finite difference method is used, where parabolic variation of the plate thickness is studied. The results for E-FG plates are given in dimensionless graphical forms; and the effects of material and geometric properties on displacements and normal stresses through the thickness are determined.

Elasto-plastic thermal stress analysis of functionally graded hyperbolic discs

  • Demir, Ersin;Callioglu, Hasan;Sayer, Metin
    • Structural Engineering and Mechanics
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    • v.62 no.5
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    • pp.587-593
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    • 2017
  • The objective of this analytical study is to calculate the elasto-plastic stresses of Functionally Graded (FG) hyperbolic disc subjected to uniform temperature. The material properties (elastic modulus, thermal expansion coefficient and yield strength) and the geometry (thickness) of the disc are assumed to vary radially with a power law function, but Poisson's ratio does not vary. FG disc material is assumed to be non-work hardening. Radial and tangential stresses are obtained for various thickness profile, temperature and material properties. The results indicate that thickness profile and volume fractions of constituent materials play very important role on the thermal stresses of the FG hyperbolic discs. It is seen that thermal stresses in a disc with variable thickness are lower than those with constant thickness at the same temperature. As a result of this, variations in the thickness profile increase the operation temperature. Moreover, thickness variation in the discs provides a significant weight reduction. A disc with lower rigidity at the inner surface according to the outer surface should be selected to obtain almost homogenous stress distribution and to increase resistance to temperature. So, discs, which have more rigid region at the outer surface, are more useful in terms of resistance to temperature.

A study on the Conversion Loss by the Thickness of the Bonding Medium in the Elastic Delay Lines. (탄성파지연선에서 접착제의 두께에 의한 변환손실에 관하여)

  • 김종상;이전영
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.13 no.6
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    • pp.1-6
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    • 1976
  • In this paper, the methode of calculating conversion loss is proposed by considering the thickness of bonding medium between electrode and delay material in the vibrator of Elastic delay lines. As the result of computations using digital computer, it is shown that the thickness of bonding medium must be less than about 1/100 of the thickness of vibrator and when the thickness of electrode is about 1110 of vibrator, the center fnequency is shifted. When the thickness of bonding medium is equal to or more than the thickness of vibrator, the 리uctuations in frequency Bandwidth become larger and larger.

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