• 한국광학회지
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• 제6권1호
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• pp.33-38
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• 1995

$Ce:YAlO_{3}$ 단결정 재료에 대한 5d 준위로부터 전도대로의 여기상태 흡수스펙트럼을 최초로 측정하였다. 이를 위해 XeCl레이저의 308nm와 색소레이저의 400-650nm의 빔을 사용하였고 555nm와 465nm에서 최대치를 갖는 흡수띠를 얻었으며 이로부터 여기상태 흡수 cross section과 oscillator strength를 계산하였다. 또한 5d 준위로 부터 비발광 천이과정 연구를 위해 300-700K의 온도영역에서 형광수명시간을 측정하였고, 5d 준위로부터의 ESA와 천이를 배위좌표를 사용하여 설명하였다.

• 한국자기공명학회논문지
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• 제8권1호
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• pp.1-18
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• 2004

A thioredoxin from hyperthermophile, Methanococcus jannashii (MjTRX) was characterized by use of the differential scanning calorimetry to understand the mechanisms of thermodynamic stability. MjTRX has an unfolding transition temperature of 116.5$^{\circ}C$, although the maximum free energy of the unfolding (9.9 Kcal/mol) is similar to that of E. coli thioredoxin (ETRX, 9.0 Kcal/mol). However, the temperature of maximum stability is higher than ETRX by 20$^{\circ}C$, indicating that the unfolding transition temperature increased by shifting the temperature of maximum stability. MjTRX has lower enthalpy and entropy of the unfolding compared to ETRX maintaining a similar free energy of the unfolding. From the structure and the thermodynamic parameters of MjTRX, we showed that the unfolding transition temperature of MjTRX is increased due to the decreased entropy of the unfolding. Decreasing the unfolded state entropy and increasing the folded state entropy can decrease the entropy of the unfolding. In the case of MjTRX, the increased number of proline residues decreased the unfolded state entropy and the increased enthalpy in the folded state increased the folded state entropy.

• Bulletin of the Korean Chemical Society
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• 제11권4호
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• pp.309-313
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• 1990

The rates of solvolysis of trans-$[Co(N-eten)_2Cl_2)$+ (N-eten; N-ethylethylenediamine) have been investigated using spectrophotometric method in binary aqueous mixtures containing methyl alcohol, isopropyl alcohol, t-butyl alcohol, ethylene glycol and glycerol. The values of ${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$ obtained from temperature effect on the rate constants were $80{\sim}84 kJmol^{-1}$ and $- 28{\sim} - 45 JK^{-1}mol^{-1}.$ Extrema found in the variation of the enthalpy and entropy of activation with solvent composition correlated very well with extrema in the variation of the physical properties of mixture which relate to sharp change in the solvent structure. The reaction mechanism was discussed in terms of correlation diagrams involving the exess molar Gibbs function of mixing for the binary mixtures. The behavior of this cobalt(Ⅲ) complex was compared with that of t-butyl chloride. The application of free energy cycle to the process initial state to transition state in water and in the mixture showed that the solvation of transition state had dominant effect on the rates in the mixtures. It was found that $S_N1$ character was increased with increasing the content of co-solvent in the mixture.

• 한국국방경영분석학회지
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• 제17권2호
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• pp.44-53
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• 1991

This paper is aimed to develop a Lanchester type combat model for the direct-fire engagement. This model incorporates number of combatants, inter-firing time, detection time by movement, detection probability by the signature of fire, where the inter-firing time and the detection time are assumed to follow a negative exponential distribution. The approach to modeling is as follows : in the process of an engagement, a combatant takes one of the states('observing' state or 'firing' state), a combatant is initially in the observing state, if the combatant detects a target, he changes his state from 'observing' to 'firing' and will cause attrition to the opposing forces. Thus this transition mechanism is embodied into the differential equation form with each transition rate. A limited examination of the validity has been conducted by comparison with the Monte-Carlo simulation model 'BAGSIM', and with a traditional Deterministic Lanchester model.

• Journal of Multimedia Information System
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• 제6권4호
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• pp.323-328
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• 2019

In this paper, a method of constructing an advanced sequential circuit over finite fields is proposed. The method proposed an algorithm for assigning all elements of finite fields to digital code from the properties of finite fields, discussed the operating characteristics of T-gate used to construct sequential digital system of finite fields, and based on this, formed sequential circuit without trajectory. For this purpose, the state transition diagram was allocated to the state dependency code and a whole table was drawn showing the relationship between the status function and the current state and the previous state. The following status functions were derived from the status function and the preceding table, and the T-gate and the device were used to construct the sequential circuit. It was confirmed that the proposed method was able to organize sequential digital systems effectively and systematically.

• Journal of Communications and Networks
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• 제8권2호
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• pp.220-227
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• 2006

In this paper, we present a novel approach to analyze the throughput of direct-sequence spread spectrum multiple access (DS/SSMA) unslotted ALOHA system. In the unslotted system, the departure rate of interfering transmissions is proportional to the number of current interferers that can be regarded as the system state. In order to model this state-dependency, we introduce a two-dimensional state transition model that describes the state transition of the system. This model provides a more rigorous analysis tool for the DS/SSMA unslotted ALOHA systems with both fixed and variable packet lengths. Numerical results reveal that this analysis yields an accurate system performance that coincides with the simulation results. Throughout the analysis we have discovered that the state-dependency of the departure rate causes interference averaging effect in the unslotted system and that this effect yields a higher throughput for the unslotted system than for the slotted system when supported by a strong channel coding.

• Journal of Magnetics
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• 제16권3호
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• pp.197-200
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• 2011

Using the full potential linearized augmented plane wave (FLAPW) method, the influences of uniform and tetragonal strains on the magnetic state have been explored for chemically ordered bulk $L1_2$ $FePt_3$. The ordered state displays antiferromagnetic $Q_1$ (AFM-$Q_1$) state but it transitions into antiferromagnetic $Q_2$ (AFM-$Q_2$) state at about 10% uniform strain. The ferromagnetic (FM) state is observed at 11% uniform strain. For tetragonal strain, it is also seen that the transition from AFM-$Q_1$ to AFM-$Q_2$ depends on the strength and direction of the applied strain. The FM state does not appear in this case. Magnetocrystalline anisotropy (MCA) calculations for tetragonal distortion reveal that the spin reorientation transition occurs. In addition, we find that the direction of magnetization and the magnitude of magnetic anisotropy energy strongly depend on the c/a ratio.

• 대한전자공학회논문지
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• 제24권5호
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• pp.823-832
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• 1987

This pper presents a method for constructing multiple-valued logic sequential machines based on Galois field. First, we assign all elements in GF(2**m) to bit codes using mathematical properties of GF(2**m). Then, we realized the sequencial machine circuits with and withoutm feed-back. 1) Sequential machines with feed-back are constructed by using only MUX from state-transition diagram expressing the information of sequential machines. 2) Sequential machines without feed-back are constructed by following steps. First, we assigned states in state-transition disgram to state bit codes, then obtained state function and predecessor table explaining the relationship between present states and previous states. Next, we obtained next-state function from state function and predecessor table. Finally we realized the circuit using MUX and decoder.

• 한국정보처리학회논문지
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• 제4권4호
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• pp.1004-1012
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• 1997

본 논문은 1치 논리 시뮬레이션 환경에서 효율적인 헤저드 분석을 위한새로운 TRF( Transition Rise/Fall)지연모델을 제안한다. 주어진 회로에 있어서 헤저드 분석을 수행 하기 위해 우선 응답시간 지연과 천이시간 지연을 허용하는 5치 논리 시뮬레이터 에 의해서 타이밍 분석이 수행되고, 이미 수행된 타이밍 관계를 조사하므로써 헤저드 를 검출할 수 있다.몇 개의 예제회로에 대해서 시뮬레이션을 수행한 결과를 통하여 제안한 방법을 실용성을 입증하였다.

• 열처리공학회지
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• 제14권6호
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• pp.345-349
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• 2001

This study has investigated the effect of thermal stability and mechanical property of $Fe_{80-X}P_{10}C_6B_4M_X$(X=2, 4, 6, M=transition metal) amorphous alloys fabricated by the melt-spun process. The glass transition temperature($T_g$), crystallization temperature($T_x$) and hardness increase with decreasing electron concentration (e/a) from about 7.38 to 7.18. The decrease of e/a implies the increase in the attractive bonding state between the M elements and other constituent element. The decrease in a/e leads to the enhancement of the attractive bonding state among the constituent elements which is favorable for the increase in $T_g$, $T_x$ and hardness.