• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.448-451
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• 2000

Normal zone propagation(NZP) characteristics were investigated on Ag sheathed Bi-2223 tape and cylindrical stacked conductor. Normal zone propagation(N2P) experiments with tape were conducted with refrigerator in temperature from 45 K to 77 K, 0 T. Cylindrical stacked conductor was molding with epoxy and experiments were conducted with adiabatic condition in $LN_2$. NZP velocities of tape with two condition of DC and AC were almost same at each temperature. NZP velocities of cylindrical stacked conductor were 1.9-2.4 cdsec in $LN_2$. Numerical analysis was carried out by a one-dimensional heat balance equation. As a result, simulated results of NZP velocity with Bi-2223 tape were similar to experimental results in DC.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.143-147
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• 2010

We have fabricated simple triple-layer blue-emitting phosphorescent organic light emitting diodes (OLEDs) using different thicknesses of N,N'-dicarbazolyl-3,5-benzene (mCP) host layers doped with bis[(4,6-di-fluorophenyl)-pyridinate-N,$C^{2'}$]picolmate (FIrpic) guest materials. The thicknesses of mCP:FIrpic layers were 5, 10, and 30 nm. Driving voltage, current and power efficiencies were investigated. The current efficiency was higher in the 10 nm thick mCP:FIrpic device, resulting from the better electron-hole balance. The device with 10 nm mCP:FIrpic layer exhibited the maximum current efficiency of 22.5 cd/A and power efficiency of 7.4 lm/W at a luminance of 1000 cd/$m^2$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.969-976
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• 2007

In this thesis, an anchoring energy in the upper and lower substrates of TFT-LCD cell has been modeled and applied in the numerical calculation of the molecular orientation of the TN-LCD. The molecular orientation of liquid crystals defined as tilt and twist angles was simulated using the Newton-Raphson method and the Gaussian integration method. From the results, the tilt and twist angles for the strong anchoring energy were proven to be coincide with those of the conventional results. on the other hand, for the weak anchoring energy, azimuth angles of the molecules were changed abruptly from $0^{\circ}\;to\;90^{\circ}$ near the middle area of the cell due to the balance of the anchoring energy and the elastic energy of the liquid crystals.

• Coupled systems mechanics
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• v.11 no.6
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• pp.543-556
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• 2022

Delamination of multilayered inhomogeneous beam that exhibits non-linear relaxation behavior is analyzed in the present paper. The layers are inhomogeneous in the thickness direction. The dealamination crack is located symmetrically with respect to the mid-span. The relaxation is treated by applying a non-linear stress-straintime constitutive relation. The material properties which are involved in the constitutive relation are distributed continuously along the thickness direction of the layer. The delamination is analyzed by applying the J-integral approach. A time-dependent solution to the J-integral that accounts for the non-linear relaxation behavior is derived. The delamination is studied also in terms of the time-dependent strain energy release rate. The balance of the energy is analyzed in order to obtain a non-linear time-dependent solution to the strain energy release rate. The fact that the strain energy release rate is identical with the J-integral value proves the correctness of the non-linear solutions derived in the present paper. The variation of the J-integral value with time due to the non-linear relaxation behavior is evaluated by applying the solution derived.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.397-402
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• 2023

We have developed inverted green phosphorescent organic light emitting diodes (OLEDs) using 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) and bis(carbazole-9-yl)biphenyl (CBP) hole transport layers. The driving voltage, current efficiency, power efficiency, and emission characteristics of devices were investigated. While the driving voltage for the same current density was about 1~2 V lower in the devices with the TAPC layer, the maximum luminance was higher in the device with the CBP layer. The maximum current efficiency and power efficiency were 3.2 and 2.7 times higher in the device with the CBP layer, respectively. The higher efficiency in the CBP device resulted from the enhanced hole-electron balance although weak parasitic recombination takes place in the CBP hole transport layer.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.4
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• pp.257-263
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• 2011

The budgets of fresh water, salt and nutrients were estimated in order to clarify the characteristics of material cycle in the Gamak Bay in 2006 with Simple Box budget Model. Outflow volume of freshwater into system was approximately $-174.2{\sim}72.5{\times}10^3m^3/day$. Inflow masses of DIP and DIN were approximately 397.0~1158 mole/day and 1750~8328 mole/day, respectively. The Source or sink of DIP was under the control of the variation of fresh water budget in the system. the mass balance and NEM was largely determined by flushing time of material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.108-111
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• 2004

An efficiency and brightness of the Organic Light-emitting Diodes(OLEDs) by insertion of the novel layer between a singlet emitter and an electron transporting layer without doping processes, has been improved. The novel layers named as the K-M1 and K-M2 layers have shown the excellent improvement in the carrier balance and recombination efficiency. New devices using the K-M1 and K-M2 layers have shown a high efficiencies of over 15cd/A and 61m/W$(at\;20mA/cm^2)$, and brightness of over $16,000cd/m^2(at\;100mA/cm^2)$, respectively.

• Journal of Society of Preventive Korean Medicine
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• v.11 no.1
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• pp.109-129
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• 2007

This study aims at grasping the relativity between laborers' yangseng level and stress so as to present the groundwork for preventive oriental medicine approach in industrial health. The researcher prepared the questionnaire on general character, health-related yangseng level and chose 632 people to execute Autonomic balance test through heartbeat change. The collected material was analyzed by SPSS and tested by T-test, ANOVA. The general yangseng level average is 3.27, morality yangseng 3.91, sleep yangseng 3.39, mind yangseng 3.32, sex life yangseng 3.29, exercise yangseng 3.14, activities and rest yangseng 3.07, diet yangseng 2.95, seasonal yangseng 2.84. The highest is morality yangseng and seasonal yangseng is the lowest. In the aspect of yangseng level : Having a spouse, Non-smoking, Non-drinking, Regular exercising, Sufficient sleeping have higher yanseng levels. In Autonomic balance test, age from 35 to 40 has the highest autonomic activity and job period from 5 years to 10 years has the highest stress resistance. Non-smokers have high autonomic activity and stress resistance. Further, have low autonomic balance, stress index and fatigue strength. In the case of regular exercising person, he/she has high autonomic activity and stress resistance with low stress index. Regarding sleeping time, autonomic balance is the highest when he/she sleeps less than 6 hours. Stress resistance is the highest when he/she sleeps 7 hours and stress index is the highest when he/she sleeps 6 hours. After comparing the relativity between yangseng level autonomic balance test, only exercise yangseng has plus factor on autonomic activity and stress resistance and minus factor on stress ind ex and fatigue strength. Yangseng level has been affected by individual character and daily habits. Also stress is more influenced by daily habits than by individual character. We can find the relativity of exercise yangseng between yangseng and stress which suggests that we need to take measures to win over stress in individual health in the near future.

• Physical Therapy Rehabilitation Science
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• v.5 no.3
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• pp.138-142
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• 2016

Objective: The purpose of this study was to investigate how light touch with a finger affects balance ability when a posture is maintained in the condition of visual information blockage and to provide a fundamental material for developing balance ability in the process of rehabilitation treatment. Design: Cross-sectional study. Methods: The study subjects were 17 healthy men and women in their twenties and thirties who were studying at S University in Seoul. The system was comprised of an equilateral triangular force platform. Subjects were asked to step on the foot position of the force platform (Good Balance, Finland) barefooted for 30 seconds, with eyes closed, hands hanging down loosely, and feet comfortably apart. It was connected to a laptop by using Bluetooth technology. An experiment was conducted in the following three circumstances: 1) no-touch trial, 2) light touch to the back (T7 area), and 3) light touch to the middle finger of the left hand. Each subject was given a 10-minute break between consecutive measurements. The experimental circumstances were performed randomly. Anteroposterior sway (APSV), mediolateral sway velocity (MLSV), and velocity moment (VM) were measured. Results: The APSVs (mm/s) were $9.32{\pm}3.37$ and $5.45{\pm}2.98$; the MLSVs (mm/s), $6.39{\pm}3.35$ and $3.31{\pm}2.48$; and VM ($mm^2/s$), $17.13{\pm}11.75$ and $6.76{\pm}8.31$ in the first and second experimental circumstances, respectively. APSV, MLSV, and VM values were significantly improved with the 1) no-touch trial and 2) light touch to the back trail conditions compared with the 3) light touch to the middle finger of the left hand condition (p<0.05). Conclusions: This study revealed that the balance ability for maintaining a body posture was influenced more by light touch to the back (T7) than by light touch with the sensitive fingertip and body sway diminished after visual information was blocked.

• Journal of Korean Medical Ki-Gong Academy
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• v.10 no.1
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• pp.100-129
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• 2007

This study aims at grasping the relativity between laborers' yangseng level and stress so as to present the groundwork for preventive oriental medicine approach in industrial health. The researcher prepared the questionnaire on general character, - health-related yangseng level and chose 632 people to execute Autonomic balance test through heartbeat change. The collected material was analyzed by SPSS and tested by T-test, ANOVA The general yangseng level average is 3.27, morality yangseng 3.91, sleep yangseng 3.39, mind yangseng 3.32, sex life yangseng 3.29, exercise yangseng 3.14, activities and rest yangseng 3.07, diet yangseng 2.95, seasonal yangseng 2.84. The highest is morality yangseng and seasonal yangseng is the lowest. In the aspect of yangseng level: Having a spouse, Non-smoking, Non-drinking, Regular exercising, Sufficient sleeping have higher yangseng levels. In Autonomic balance test, age from 35 to 40 has the highest autonomic activity and job period from 5 years to 10 years has the highest stress resistance. Non-smokers have high autonomic activity and stress resistance. Further, have low autonomic balance, stress index and fatigue strength. In the case of regular exercising person, he/she has high autonomic activity and stress resistance with low stress index. Regarding sleeping time, autonomic balance is the highest when he/she sleeps less than 6 hours. Stress resistance is the highest when he/she sleeps 7 hours and stress index is the highest when he/she sleeps 6 hours. After comparing the relativity between yangseng level autonomic balance test, only exercise yangseng has plus factor on autonomic activity and stress resistance and minus factor on stress index and fatigue strength. Yangseng level has been affected by individual character and daily habits. Also stress is more influenced by daily habits than by individual character. We can find the relativity of exercise yangseng between yangseng and stress which suggests that we need to take measures to win over stresses in individual health in the near future.