• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.179-180
• /
• 2007

Single crystal $AgGaSe_2$ layers were grown on thoroughly etched semi-insulating GaAs(100) substrate at $420^{\circ}C$ with hot wall epitaxy (HWE) system by evaporating $AgGaSe_2$ source at $630^{\circ}C$. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of single crystal $AgGaSe_2$ thin films measured with Hall effect by van der Pauw method are $4.05{\times}\;10^{16}/cm^3$, $139\;cm^2/V{\cdot}s$ at 293 K. respectively. The temperature dependence of the energy band gap of the $AgGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=1.9501\;eV\;-\;(8.79{\times}10^{-4}\;eV/K)T^2$/(T + 250 K). The crystal field and the spin-orbit splitting energies for the valence band of the $AgGaSe_2$ have been estimated to be 0.3132 eV and 0.3725 eV at 10 K, respectively, by means of the phcitocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}So$ definitely exists in the $\Gamma_5$ states of the valence band of the $AgGaSe_2$. The three photocurrent peaks observed at 10 K are ascribed to the $A_1$-, $B_1$-, and $C_1$-exciton peaks for n = 1.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2002.12a
• /
• pp.32-33
• /
• 2002

최근 세계적 주목을 받고 있는 spin FET[1] 소자의 구현은 강자성 물질에 의하여 반도체에 주입된 spin 편향된 전자가 반도체 계면에 유도된 전기장의 영향을 받아 spin-orbit interaction을 하는 mechanism(Rashbar effect)이 근간을 이루고 있다. 작은 band gap을 가지는 반도체(narrow gap 반도체)는 작은 유효질량의 전자에 의해서 이러한 Rashbar effect[2]를 크게 할 수 있는 물질로서, spin FET 구현을 위한 강력한 후보이며, 요즘 한창 연구되고 있는 주제이기도 하다[3]. (중략)

• Journal of the Korean Magnetic Resonance Society
• /
• v.12 no.2
• /
• pp.103-110
• /
• 2008

Spin Hamiltonian for the paramagnetic center with a three-fold symmetry and high spin ($S{\geq}2$) multiplicity should contain the fourth order zero-field splitting (ZFS) terms. Electron magnetic resonance transition lines of the center with S = 5/2 are expected to split in a pair when the magnetic field is applied off the principal axes of ZFS, while they are superimposed when the magnetic field is applied parallel to the principal axes of ZFS. In this study we report that the transition lines of $Mn^{2+}$ centers at the three-fold symmetric sites in $LiNbO_3$, chemically equivalent but physically different, split in two due to the nonzero fourth order ZFS term.

• Journal of Yeungnam Medical Science
• /
• v.6 no.2
• /
• pp.127-132
• /
• 1989

The upshoot and downshoot in Duane's retraction syndrome is believed to be related to a leash effect from the lateral rectus muscle. When the eye is rotated into the adducted position, the lateral rectus muscle slips over the globe, producing the up-and downshoot on adduction. The splitting of the ends of the lateral rectus into a Y configuration prevents the rotation of the globe up or down by stabilizing the muscle's position on the eye. Three patients with Duane's retraction syndrome demonstrated abnormal vertical movement on adduction and underwent a Y-splitting on the lateral rectus. In all patients, marked decrease in the up-and downshoot is noted after surgery.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.11a
• /
• pp.71-72
• /
• 2006

The stochiometric mixture of evaporating materials for the $ZnIn_2S_4$ single crystal thin film was prepared from horizontal furnace. To obtain the $ZnIn_2S_4$ single crystal thin film. $ZnIn_2S_4$ mixed crystal was deposited on throughly etched semi-insulating GaAs(100). In the Hot Wall Epitaxy(HWE) system. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the $ZnIn_2S_4$ single crystal thin film, we have found that the values of spin orbit splitting ${\Delta}So$ and the crystal field splitting ${\Delta}Cr$ were 0.0148 eV and 0.1678 eV at $10_{\circ}K$, respectively.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.11a
• /
• pp.120-123
• /
• 2003

In order to evaluate the applicability of steel slag aggregates for tetrapod concrete, the properties of concrete as structural material were investigated. The biochemical research of marine concrete using steel slag aggregates was also carried out. The tested concrete properties are slump, air content, compressive strength, splitting tensile strength, elastic modulus, carbonation, hydration heat, freezing and thawing, sulfate attack, drying shrinkage, etc. The biochemical experiments are carried to research the propagation and reproduction of seaweeds and survival of bottom dwelling species. According to the experimental results, the steel slag aggregate content did not have a significant effect on compressive strength, splitting tensile strength and elastic modulus. The durability of concrete was not influenced by the steel slag aggregate content. From the biochemical research, steel slag aggregate can be evaluated as the material that is ideally suited for promoting propagation and reproduction of seaweeds and survival of bottom dwelling species.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 1998.10a
• /
• pp.201-209
• /
• 1998

The propagation of water waves over irregular bottom bathymetry and around islands involves many process. In this study of numerical model is developed current in water of varying depth. The method used is splitting method and minimax approximation. This numerical method used is Crank-Nicolson scheme. This model is applied to Vincent shoal and compared with laboratory data. The results agreed well with laboratory data. The results agreed well with laboratory data. Current effect is considered in this study. So, the model is used for the estimation of rip current in the slowly varying topography.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.21 no.8
• /
• pp.695-698
• /
• 2008

We investigated the characteristics of Strained-Si-on-Insulator (sSOI) MOSFETs with 0.7% tensile strain. The sSOI MOSFETs have superior subthreshold swing under 70 mV/dec and output current. Especially, the electron and hole were increased in sSOI MOSFET. The electron and hole mobility in sSOI MOSFET were 286$cm^2/Vs$ and 151$cm^2/Vs$, respectively. The carrier mobility enhancement is due to the subband splitting by 0.7% tensile strain.

• 한국전산유체공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.189-190
• /
• 2003

A New kinetic scheme for the compressible Navier-Stokes equations is developed. While the conventional approach, such as KFVS scheme, employs the splitting algorithm and computes the numerical flux on the basis of the collisionless equation, the present approach employs the splitting algorithm in the evaluation of the numerical flux, where the collision effect is explicitly taken into account. However, the initial condition employed in the computation is slightly different from the conventional Chapman-Enskog NS distribution function. The present study also reveals the background of the existing kinetic schemes. such as the KFVS scheme and Gas-Kinetic BGK scheme.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1495-1498
• /
• 2003

Recently, self-healing methods of a cracked matrix, especially polymeric composite materials, became the center of engineering researchers. In this paper, we summarized the self-healing concept for polymeric composite materials and investigated the effect of microparticle on the crack growth behavior in colorless and transparent matrix by experimental observation to describe the crack propagation around the microparticle inside epoxy matrix composite. Compression splitting test for the specimen involving microparticle was conducted. In addition, FE analysis was pursued to present the stress contour around microparticle in the matrix. Through the experiments and FE analysis, we found that the size. relative position, bonding condition and relative stiffness of microparticle are important parameters to decide the direction of crack propagation, which is related to the rupture of microparticle for self-healing