• 대한화학회지
• /
• 제26권1호
• /
• pp.7-17
• /
• 1982

Diels-Alder 반응의 배향성에 대한 치환기 및 산촉매 효과를 예측하기 위해 또 Lewis산이 diene, dienophile과의 착물 형성의 경쟁성을 예측하기 위해서 Diels-Alder 반응의 열 또는 촉매반응에 FMO이론을 적용하여 CNDO/2 방법으로 고찰하였다. (1)Acetoxy로 치환된 diene의 카르보닐 산소는 dienophile보다 더 큰 음 전하를 갖기 때문에 Lewis 산이 dienophile보다는 diene에 우선적으로 배위하였다. (2) 본 연구의 대부분의 반응은 Neutral electron demand 반응형태를 가지므로 4-c, 2-c 및 정량적인 SOI방법이 일반적으로 실험적인 주 배향체와 일치함을 알았다. (3) 황은 빈 d-궤도 함수의 참여로 인해서 산소에 비해 치환기의 인접된 말단 탄소원자의 LUMO를 크게 활성화 시켜 Neutral electron demand 반응에서의 diene LUMO-dienophile HOMO 상호작용을 크게 해주어 배향성 결정에 주도적 역할을 하게 되었다.

• Kyungpook Mathematical Journal
• /
• 제54권4호
• /
• pp.677-684
• /
• 2014

In the theory of hypergeometric functions of one or several variables, a remarkable amount of mathematicians's concern has been given to develop their transformation formulas and summation identities. Here we aim at generalizing the following transformation formula for the Exton's triple hypergeometric series $X_{12}$ and $X_{17}$: $$(1+2z)^{-b}X_{17}\;\left(a,b,c_3;\;c_1,c_2,2c_3;\;x,{\frac{y}{1+2z}},{\frac{4z}{1+2z}}\right)\\{\hfill{53}}=X_{12}\;\left(a,b;\;c_1,c_2,c_3+{\frac{1}{2}};\;x,y,z^2\right).$$ The results are derived with the help of two general hypergeometric identities for the terminating $_2F_1(2)$ series which were very recently obtained by Kim et al. Four interesting results closely related to the Exton's transformation formula are also chosen, among ten, to be derived as special illustrative cases of our main findings. The results easily obtained in this paper are simple and (potentially) useful.

• 한국정밀공학회지
• /
• 제22권3호
• /
• pp.38-45
• /
• 2005

In this paper, a bird type biped robot for entertainment controlled by R/C servo motors, is built using the embedded RTOS (Real Time Operating System). ${\mu}C/OS-II$ V2.00 is used fur RTOS and the board 80C196KC for main CPU. A control algorithm of R/C servo motors is proposed on ${\mu}C/OS-II's$ preemptive and deterministic property without any extra PWM module. The realized biped robot has 19DOF, that is, 12DOF for both legs, 6DOF for both arms and 1DOF for neck. To verify the proper walking process, ZMP(Zero Moment Point) theory is applied and the simulation has been done by ADAMS.

• 한국초전도ㆍ저온공학회논문지
• /
• 제15권2호
• /
• pp.16-19
• /
• 2013

The magneto-resistivity and electric field-current density (E-J) curves were investigated up to a magnetic field 9 T in the optimally doped $BaFe_{1.8}Co_{0.2}As_2$ single crystal with a superconducting temperature ($T_c$) of 24.6 K. The E-J Scaling behaviors below and above vortex glass transition temperature ($T_g$) were found, confirming the existence of the vortex glass phase transition. The critical exponents for the diverging spatial and time correlations at $T_g$, were obtained as v = $1.1{\pm}0.1$ and z = $4.5{\pm}0.3$, respectively. The obtained critical exponents are in good agreement with the predicted values of v ~ 1 - 2 and z > 4 within the 3D vortex glass theory.

• Advances in concrete construction
• /
• 제1권3호
• /
• pp.239-252
• /
• 2013

Mortar microstructure is considered as a three-phase composite material, which is cement paste, fine aggregate and interfacial transition zone. Interfacial transition zone is the weakest link between the cement paste and fine aggregate, so it has a significant role to determine the properties of cementitious composites. In this study, specimens (w/c = 0.35, 0.45, 0.55) with various volume fractions of fine aggregate ($V_f$ = 0, 0.1, 0.2, 0.3 and 0.4) were cast and tested. To predict the equivalent migration coefficient ($M_e$) and migration coefficient of interfacial transition zone ($M_{itz}$), double-inclusion method and Mori-Tanaka theory were used to estimate. There are two stages to estimate and calculate the thickness of interfacial transition zone (h) and migration coefficient of interfacial transition zone ($M_{itz}$). The first stage, the data of experimental chloride ion migration coefficient ($M_s$) was used to calculate the equivalent migration coefficient of fine aggregate with interfacial transition zone ($M_e$) by Mori-Tanaka theory. The second stage, the thickness of interfacial transition zone (h) and migration coefficient of interfacial transition zone ($M_{itz}$) was calculated by Hori and Nemat-Nasser's double inclusion model. Between the theoretical and experimental data a comparison was conducted to investigate the behavior of interfacial transition zone in mortar and the effect of interfacial transition zone on the chloride migration coefficient, the results indicated that the numerical simulations is derived to the $M_{itz}/M_m$ ratio is 2.11~8.28. Additionally, thickness of interfacial transition zone is predicted from $10{\mu}m$, 60 to $80{\mu}m$, 70 to $100{\mu}m$ and 90 to $130{\mu}m$ for SM30, M35, M45 and M55, respectively.

• 한국환경보건학회지
• /
• 제22권1호
• /
• pp.12-20
• /
• 1996

This study was carried out to investigate the change of average .specific resistance according to suspension concentration for study phenomena occurring during filtration period. As the results of this study, the following conclusions were obtained. The average specific resistance in 1% $CaCO_3$ suspension was showed power function(R=0.99), whereas in TOYO 5C and TOYO 5A paper were made little difference under high pressure. It represented from results that filtration theory in concord with cake filtration was no affected the average specific resistance of filter medium in cake filtration. In case of 0.1% $CaCO_3$ suspension filtration, the TOYO 5C was showed power function, whereas in TOYO 5A paper differently. In the present study, the $P_1$ value was calculated from the average specific resistance by filtration method. Therefore, $P_1$ value were $1.68\times 10^4Pa$, $4.05\times 10^3Pa$, and $3.15\times 10^3Pa$ in $5.3\times 10^4Pa$, $1.3\times 10^4Pa$, and $8.2\times 10^3Pa$, respectively. We concluded that propriety of new filtration theory was also proved.

• Structural Engineering and Mechanics
• /
• 제18권1호
• /
• pp.79-90
• /
• 2004

A high precision shear deformable triangular element has been proposed for bending analysis of triangular plate. The element has twelve nodes at the three sides and four nodes inside the element. Initially the element has thirty-five degrees of freedom, which has been reduced to thirty by eliminating the degrees of freedom of the internal nodes through static condensation. Plates having different boundary conditions, side ratios (b/a) and thickness ratios (h/a = 0.001, 0.1 and 0.2) have been analyzed using the proposed shear locking free element. Concentrated and uniformly distributed transverse loads have been used for the analysis. The formulation is made based on first order shear deformation theory. For validation of the present element and formulation few results of thin triangular plate have been compared with the analytical solutions. Results for thick plate have been presented as new results.

• 천문학회보
• /
• 제39권2호
• /
• pp.38-38
• /
• 2014

Despite the great success that stellar evolution theory have enjoyed during the last 50 years, new challenges are emerging with recent observations of supernovae: many aspects of supernovae cannot be easily explained by the standard scenarios on supernova progenitors. A few examples include the red supergiant problem - the dearth of Type IIP supernova progenitors with masses higher than about 16 Msun, the non-detection of Type Ib/c supernova progenitors despite very deep searches in pre-supernova optical images, the unexpected blue colors of some Type IIn supernova progenitors, and the exotic stellar explosions of both ultra-faint and super-luminous types that have been only recently discovered. By confronting these observations with new stellar evolution models, we are making significnt progress in better understanding the role of metallicity, rotation and binary interactions for the pre-supernova evolution of massive stars. In this talk, I will give a brief review on the recent observational constraints on supernova progenitors and a progress report on several research projects that deal with pair-instability supernovae from the local Universe, type Ib/c supernovae from massive binary systems, and some peculiar stellar explosions like SN2012Z.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제51권2호
• /
• pp.85-91
• /
• 2002

A novel multi-section power divider configuration is Proposed to obtain wide-band frequency performance up to microwave frequency region. Design procedures for the proposed microwave broadband power divider are composed of a Planar multi-section three-Ports hybrid and a waveguide transformer design procedures. The multi∼section power divider is based on design theory of the optimum quarter- wave transformer Furthermore, in order to obtain the broadband isolation performance between the two adjacent output ports, the odd mode equivalent circuit should be matched by using the lossy element such as resistor. The derived design formula for calculating these odd mode∼matching elements is based on the singly terminated filter design theory. The waveguide transformer section is designed to suppress the propagation of the higher order modes such as waveguide modes due to employing the metallic electric wall. Simulation and experiment show excellent performance of multi section power divider.

• EDISON SW 활용 경진대회 논문집
• /
• 제5회(2016년)
• /
• pp.62-66
• /
• 2016

Tumor suppressor protein p53 loses its function upon binding with the HDM2 protein, and inhibiting the p53-HDM2 interaction is critical to suppress tumor cell growth. Recently, the cyclized helix-loop-helix peptide (cHLH) mimicking the ${\alpha}-helix$ part of the p53 protein has been designed and found to exhibit high binding affinity with HDM2. Here, we report the structural and thermodynamic characteristics of the bound complex of the cHLH peptide with the HDM2 protein. We performed molecular dynamics simulations to investigate the structural features of the cHLH peptide as well as its complex with the HDM2. The binding free energy calculation based on the integral equation theory was also executed to quantify the binding affinity for the cHLH/HDM2 complex and to understand the factors contributing to the binding affinity. We found a variety of factors for the helix stability of the cHLH peptide as well as in the complexation with the HDM2, which may provide an insight into the development of anti-cancer drug designs.