• Defense and Technology
• /
• no.11 s.129
• /
• pp.12-21
• /
• 1989

1974년 Pokharan에서 실시된 핵실험으로 인도는 핵장비를 폭발시킨 여섯번째 국가가 되었다. 이어 1980년에 우주 운반체의 발사로 인도는 인공위성을 제작하고 독자적인 운반체를 이용, 궤도에 진입시킨 여섯번째 나라가 되었다. 또한 1989년 5월 중거리 탄도미사일(IRBM) Agni의 성공적인 발사로 인도는 미국, 소련, 중국, 프랑스 그리고 영국에 이어 여섯번째로 탄도탄 보유국가가 되었다. 현재 인도는 제3세계 총생산량의 31%를 차지함으로써 26개국에 달하는 제3세계 무기생산국 중에서 선두를 달리고 있다

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.9
• /
• pp.138-148
• /
• 1996

In moving structures such as robots and feeders of production lines, vibrations may not be ignored. Recently it becomes a big problem to control the vibration in a motion because moving structures are in higher speed, larger size and lighter weight. In this study a nonlinear system was model- led and identified by using neural networks and the vibration in motions was controlled actively by using a neural network controller. To investigate vilidity of this method, an experimental apparatus was made and tested. The model was composed of a DC servomotor, a carrier and a flexible plate. Its motion was measured by a gap sensor and an encoder. Trapezoidal, cycloid and trapecloid type trajectories were used in this exper- riment. Computer simulations and experiments weredone for each trajectory.

• Journal of the Korean Chemical Society
• /
• v.23 no.2
• /
• pp.65-74
• /
• 1979

An effect of the spin-orbit coupling interaction of ligand orbitals on the ground state for octahedral $[Ti(Ⅲ)A_3B_3]$, $ [V(Ⅲ)A_3B_3]$, $ [Fe(Ⅲ)A_3B_3]$ and $ [Ni(Ⅱ)A_3B_3]$ type complexes has been investigated in this work, applying the degenerate perturbation theory. The wave functions are not affected but the energy level splitting for the ground state of these complexes by the spin-orbit coupling interaction of ligand orbitals. The extent of effect on the energy level splitting for the ground state is decreased in order Ti(Ⅲ) > V(Ⅲ) > Fe(Ⅲ).

• Journal of the Korean Chemical Society
• /
• v.24 no.1
• /
• pp.15-19
• /
• 1980

CNDO/2, EHT molecular orbital methods are used to investigate the electronic structure and reactivity of glycinato, glycine ester ligands. The results show that bidentate glycinato has a more stable structure, Gly-I with a $105.9^{\circ}$dihedral angle between ${\Delta}O_4C_3C_2$ and ${\Delta}C_3C_2N_1$ than Gly-Ⅱ. The electron inductive effects in the alkyl group substituted glycine ester ligands can also be derived from the calculation. According to the electron density, qN of ligands on the basis of CNDO/2 MO calculations, it is concluded that the stabilities are in the order of glycinato > Gly-Et-ester > Gly-i-Pr-ester > Gly-Me-ester.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.8
• /
• pp.17-29
• /
• 1999

Inter-Satellite Links(ISL) technique in the Polar Orbit Satellite plays the key role in the communication methods in IRIDIUM system, where the ISL is commonly established between neighbor satellites. The system has major drawbacks in maintaining the multi-hopping link connectivities while the satellite nodes are communicating each other. The proposed system is newly designed to allow diagonal link connections between the satellites and shows how it does improve the performance. The optimized number of satellites in the terms of their altitudes and visible distance are calculated. The traffic parameters and the probability of blocking are analyzed to compare the visible satellite link method with the neighbor link method mathermatically.

• Journal of the Korean Chemical Society
• /
• v.27 no.6
• /
• pp.391-398
• /
• 1983

The reaction for the hydrogen abstraction from substituted-toluenes by t-butoxyl and t-butyl radical have been studied MO theoretically using CNDO/2 method. The reaction for the abstraction from substituted-toluenes by t-butoxyl radical showed the negative ${\rho}$ values from Hammett equation, since t-butoxyl radial is electrophilic, relatively low energy SOMO, which can interact with HOMO energy of substituted-toluens. On the other hand, t-butyl radical is nucleophilic, relatively high energy SOMO, which can interact with LUMO energy of substituted-toluenes. And so the reaction of abstraction from substituted-toluenes by t-butyl radical exhibited positive ${\rho}$ values.

• Journal of the Korean Chemical Society
• /
• v.38 no.6
• /
• pp.405-410
• /
• 1994

Molecular orbital calculations suggest that an interaction between the psoralen derivatives of excite state and the thymine of ground state is dicussed in terms of their differing abilities to molecular complex. PM3-CI-UHF indicates that photocycloadducts across the C3-C4 and C4'-C5' double bonds of the methylpsoralen and hydroxypsoralen with thymine C5-C6 double bonds were deduced to be formed by their preferable frontier orbital interactions. The electronic properties of psoralen derivatives in the ground and excited states correlate with this difference in structure-activity relationship.

• Journal of the Korean Chemical Society
• /
• v.21 no.6
• /
• pp.434-439
• /
• 1977

The electronic structures of 4-pyridone and lutidone are studied by the SCF MO-CI PPP method and by the configuration analysis method. The spectral data are consistent with the values calculated by the method. The polarization of $S_1({\pi},{\pi}^*)$ state is along the long molecular axis in both compounds. The lowest $({\pi},{\pi}^*)$1 state shows significant charge transfer (16∼18%) from ${\pi}$ bonding orbital of C=O moiety to ${\pi}^*$ antibonding orbital of divinyl amine moiety. The lowest triplet state shows much larger charge transfer (24∼29 %) but in opposite direction compared to that of $S_1({\pi},{\pi}^*)$ state.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.2 no.3
• /
• pp.80-89
• /
• 1998

Propulsion subsystem transfers KOMPSAT into mission orbit and controls its attitude. Design factor consists of structure safety, electrical circuit design, consumable power estimation of thermal hardwares, damping device design of fuel transient pressure, and system configuration design by considering plume effect from thruster firing. System level analysis should be performed for verification of system design under launch vehicle and orbital environment. Electrical functional test of thermal control hardware, proof pressure test, cleanliness verification test, and internal/external leakage test of fuel feeding system should be carried out for performance estimation of propulsion system. Design and assembly process of propulsion subsystem was depicted and reliability of system was verified by test analysis in this paper.

• Journal of the Korean Chemical Society
• /
• v.28 no.5
• /
• pp.279-283
• /
• 1984

${\beta}$-Substituent effect on the reactivity of retro-ene decarboxylation of but-3-enoic acid was investigated theoretically. It was found that charge effect is important not only through ${\pi}$-electron transfer as has been claimed to rationalize experimental results but also through polarization as found for the $CH_3$ substituent. The reactivity was not determined by the charge effect alone but the HOMO-LUMO energy gap was also found to affect the reactivity. In general it was confirmed that the greater the ${\pi}$-electron donating power of the substituent, the greater is the reactivity.