• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.395-396
• /
• 2008

Copper-Phthalocyanine (Cu-Pc) thin films of 100nm thickness have been deposited on silicon substrates as the different heating temperatures by thermal evaporation deposition technique. X-ray patterns showed with different temperature conditions at the $2\theta$ range of 5-$55^{\circ}$. The surface roughness of Cu-Pc thin films was investigated by using an atomic force microscope (AFM). A scanning electron microscope (SEM) has been used to characterize the micro-structures and morphologies depended on the substrate temperatures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.8-8
• /
• 2008

Two-dimensional photonic quasicrystal (PQCs) template patterns have been fabricated on a $1.1{\mu}m$-thick DMI-150 photoresist using a multiple-exposure holographic method. A 442-nm HeCd laser was utilized as a light source and the holographic exposure was carried out at a fixed angle of $\theta=6^{\circ}$. After the first holographic exposure, the sample was rotated to a proper angle and the second exposure was performed to the same manner. This exposure process was repeated n/2 times to obtain n-fold symmetric PQC patterns and then the sample was developed. The fabricated PQCs exhibited 8, 10 and 12-fold rotational symmetry and the diffraction patterns using a 632.8-nm HeNe laser were observed for n-rotation symmetry corresponding n-fold PQCs. The fabricated PQC template patterns were examined using scanning electron microscopy(SEM). Transmission spectra were measured fourier transform infrared(FTIR) spectrometer.

• Journal of Korean Institute of Industrial Engineers
• /
• v.22 no.3
• /
• pp.485-498
• /
• 1996

For a tree T rooted at a concentrator location in a telecommunication system, we assume that the capacity H for the concentrator is given and a profit $c_v$, and a demand $d_v$, on each node $\upsilon$ of T are also given. Then, the capacitated subtree of a tree problem (CSTP) is to find a subtree of T rooted at the concentrator location so as to maximize the total profit, the sum of profits over the subtree, under the constraint satisfying that the sum of demands over the subtree does not exceed H. In this paper, we develop a pseudopolynomial-time algorithm for CSTP, the depth-first dynamic programming algorithm. We show that a CSTP can be solved by our algorithm in $\theta$ (nH) time, where n is the number of nodes in T. Our algorithm has its own advantage and outstanding computational performance incomparable with other approaches such as CPLEX, a general integer programming solver, when it is incorporated to solve a Local Access Telecommunication Network design problem. We report the computational results for the depth-first dynamic programming algorithm and also compare them with those for CPLEX. The comparison shows that our algorithm is competitive with CPLEX for most cases.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.5
• /
• pp.450-456
• /
• 2006

In this paper, we report the changes of morphology, transmittance and photoluminescence (PL) in hydrogenated amorphous $As_{40}Ge_{10}Se_{15}S_{35}$ thin films, thermally deposited at the vapor incidence angles (${\theta}$) of $0^{\circ},\;45^{\circ}\;and\;80^{\circ}$. The hydrogenation was carried out under the condition of a $H_2$ pressure ($P_H$) of 20 atm and an annealing temperature range, $T_{Anneal}$ of $150^{\circ}C{\sim}210^{\circ}C$. A columnar structures with an inclination angle of approximately $65{\sim}70^{\circ}$ was formed in $80^{\circ}$-deposited films and then the columnar was broken after hydrogenation. Transmittance increases with an increase of deposition angle and by the hydrogenation. In particular, a broad PL band on the extended region is observed in obliquely deposited films and it increases during the hydrogenation.

• Transactions on Electrical and Electronic Materials
• /
• v.12 no.4
• /
• pp.169-173
• /
• 2011

In this study, Al-N codoped p-type zinc oxide (ZnO) thin films were deposited on Si and homo-buffer layer templates in a mixture of $N_2$ and $O_2$ gas with ceramic ZnO:(2 wt% $Al_2O_3$) as a sputtering target using DC- magnetron sputtering. X-ray diffraction spectra of two-theta diffraction showed that all films have a predominant (002) peak of ZnO Wurtzite structure. As the $N_2$ fraction in the mixed $N_2$ and $O_2$ gases increased, field emission secondary electron microscopy revealed that the surface appearance of codoped films on Si varied from smooth to textured structure. The p-type ZnO thin films showed carrier concentration in the range of $1.5{\times}10^{15}-2.93{\times}10^{17}\;cm^{-3}$, resistivity in the range of 131.2-2.864 ${\Omega}cm$, and mobility in the range of $3.99-31.6\;cm^2V^{-1}s^{-1}$ respectively.

• Journal of East-West Nursing Research
• /
• v.11 no.2
• /
• pp.116-123
• /
• 2005

Purpose: The purpose of this study was to analyze the influencing factors on adolescent's self-efficacy. Method: This was a descriptive study. The data were collected from 7th through 12th graders(N=1710) enrolled in middle schools(N=873) and high schools(N=837) in the metropolitan area of Daegu. The instruments had used for this study were the self-efficacy, the life event checklist, and Family APGAR. The data were analyzed using frequency, t-test, Pearson correlation coefficient, and multiple regression analysis. Result: Pearson correlation analysis revealed that there were negative correlations between the self-efficacy and the stress. However, in case of the subjects who recorded higher scores at self-efficacy they showed higher scores at family function. Stepwise multiple regression analysis revealed that powerful predictors of adolescent's self-efficacy were family function and relations of schoolmate. Conclusion: From these results, we can find that the family function and relations of schoolmate were actual factors theta affected the self-efficacy of adolescents. Accordingly, affirmative emotion in family, harmonic communication among family members and sharing housekeeping works is recommended as a useful method in order to enhance the family function, and then the self-efficacy of adolescence will be increased.

• Steel and Composite Structures
• /
• v.22 no.3
• /
• pp.613-625
• /
• 2016

The joints of the new prefabricated concrete assemble beam-column joints are put together by the hybrid joints of inserting steel under post-tensioned and non-prestressed force and both beams and columns adopt prefabricated components. The low cyclic loading test has been performed on seven test specimens of beam-column joints. Based on the experimental result, the rotation capacity of the joints is studied and the $M-{\theta}$ relation curve is obtained. According to Eurocode 3: Design of steel structures and based on the initial rotational stiffness, the joints are divided into three types; by equivalent bending-resistant stiffness to the precast beam, the equivalent modulus of elasticity $E_e$ is elicited with the superposition method; the beam length is figured out that satisfies the rigid joints and after meeting the requirements of application and safety, the new prefabricated concrete assemble beam-column joints can be regarded as the rigid joints; the design formula adopted by the standard of concrete joint classification is theoretically derived, thereby providing a theoretical basis for the new prefabricated concrete structure.

• Steel and Composite Structures
• /
• v.24 no.4
• /
• pp.455-465
• /
• 2017

This paper presents a series of ultimate and fatigue experimental investigation on concrete-filled rectangular hollow section (CRHS) X joints with Perfobond Leister rib (PBR) under tension. A total of 15 specimens were fabricated, in which 12 specimens were tested under ultimate tension and 3 specimens were investigated in fatigue test. Different parameters including PBR stiffening, brace-to-chord ratio (${\beta}$) and inclined angle (${\theta}$) were considered in the test. Each joint was tested to failure under tension load. Obtained from test result, PBR was found to improve the tension strength and fatigue durability of CRHS joint substantially. Concrete dowel consisted by PBR and concrete inside the chord stiffened the joint, which leaded to a combination failure mode of punching shear and chord plastification of CRHS joint under tension. Finite element analysis validated the compound failure mode. Stress concentration on typical spot of CRHS joint was mitigated by PBR which was observed from fatigue test. Initial fatigue crack presented in CRHS joint with PBR also differentiated with the counterpart without PBR.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.60-65
• /
• 2004

Kim et al. described and compared other methods of measuring stress triaxiality using the displacements near the side necking, proved the validities of these models and explored the effect of location where the displacements are measured using three-dimensional finite element analysis for a standard CT specimen with 20% side-grooves. In this paper, the applicability of these models to various specimen and materials are examined in detail. To consider the effects of side groove, thickness of specimen, crack length, specimen geometry and strain hardening exponents, three-dimensional finite element simulation has been performed for various specimen geometries. For a case without a side groove, in the whole the difference between the stress triaxilaity analytically evaluated and directly determined is similar. For a case with a 20% side groove the stress triaxiality is measured at the area where ${\theta}$ is smaller than $60^{\circ}$, which excludes a side grooved area.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.4
• /
• pp.51-58
• /
• 2008

This paper presents a new design of the precision stage for the reticle in lithography process and a low hunting control method for the stage. The stage has three axes for X, Y, ${\theta}_z$ those actuated by three voice coil motors individually. The designed reticle stage system has three gap sensors and voice coil motors, and supported by four air bearings and the forward/inverse kinematics of the stage were solved to get an accurate reference position. When a stage is in regulating control mode, there always exist small fluctuations(stage hunting) in the stage movement. Because the low stage hunting characteristic is very important in recent lithography and nano-level applications, a special regulating controller for ultra low hunting is proposed in this paper. Also this research proposed the 2-step transmission system for preventing the noise infection from environmental devices. The experimental results showed the proposed regulating control system reduced hunting noise as 35nm(rms) when a conventional PID generates 77nm(rms) in the same mechanical system. Besides the reticle stage has 100nm linear accuracy and $1{\mu}rad$ rotation accuracy at the control frequency of 8kHz.