The Measure of Dependency between on Two Random Variables

이천진 선문대학교 자연과학대학 1999 자연과학대학 논문집 Vol.2 No.-

In the measure of independence, synergism or antagonism of actions of two stimuli have always been assumed to be global in nature. But in general problems of quantal response assay, it is possible that two stimuli act synergistically in certain regions (that is for certain combinations of s_(1) and s_(2)), independently in some others and then antagonistically in other regions. This consideration motivates us to propose a proper selection of joint distribution function that best describes the action of the pair of stimuli under consideration. This paper discuss one solution which choose the joint distribution from some restrict class when we know how the action changes with different combinations of levels.

Applications of Lie Algebra to spectroscopic Transitions in Multi-Level Systems

Lee, Chang Jae 선문대학교 자연과학대학 1999 자연과학대학 논문집 Vol.2 No.-

일반적인 N 개의 에너지 준위를 갖는 시스템(원자, 분자)과 고전적인 전자기파와의 상호작용을 할 때 해밀토니안이 갖는 Lie 대수학적인 구조에 관하여 밝혔다. 이러한 Lie 대수학적 구조에 관한 연구는 원자 및 분자, 그리고 원자핵 스핀을 전자기장으로 결맞게(coherent) 다룰 수 있는 새로운 방법의 개발에 매우 유용할 것이다. 그러한 예로는 Average Hamiltonian 이론 및 Magnus 전개를 통한 다중 펄스열 및 펄스 모양의 디자인을 들 수 있다. We present Lie algebraic relations for the interaction of general N-level systems with an electromagnetic field. These relations should be very useful in developing novel schemes for coherently manipulating atoms, molecules, and nuclear spins with electromagnetic fields, for example, in designing multiple-pulse sequences and pulse shapes using the Average Hamiltonian Theory, and in using the Magnus expansion.

ESTIMATION OF THE ION PAIR TEMPERATURE FROM ITS DYNAMICS

Han, Chul-Hee 선문대학교 자연과학대학 1999 자연과학대학 논문집 Vol.2 No.-

Picosecond Dynamics of ion pair of different types of charge in a polar solvent ; one between 1,2,4,5-tetracyanobenzene anion and biphenyl cation, and the other between 1-Methyl- 4-Cyanopyridinium radical and biphenyl cation, Is compared. Analysis based on the Coulomb interaction in the ion pair has lead to the estimation of the average temperature for the ion pair.

Modulation of Ion Pair Dynamics by Variation of Ionic Character

한철희 선문대학교 자연과학대학 2000 자연과학논총 Vol.3 No.-

광학적으로 생성된 1,2,4,5-테드라시아노벤젠 음이온과 바이페닐 유도체 양 이온간의 이온쌍에 대한 용액상 동력학이 이온성질의 변화에 의하여 조절되는 것이 관찰되었다. 주개 분가의 오르토 위치에 친전자성 또는 친핵성 치환에 따라서 이온쌍 의 분해속도가 증가 또는 감소됨이 분석결과 나타났다. We have observed modulation of solution dynamics of the photogenerated ion pair between 1 ,2,4,5-tetracyanobenzene anion and biphenyl derivative cation by variation of ionic character. Our analysis shows that the rate of ion pair separation can be made to increase or decrease, depending on the electrophilic or nucleophilic substitution in the ortho position of the donor molecule.

Real Weight Functions for Orthogonal Polynomials in Two Variables of Bessel Type

Lee, Jeong-Keun 선문대학교 자연과학대학 1999 자연과학대학 논문집 Vol.2 No.-

이 논문에서는 한 편미분방정식을 만족시키는 2변수 직교 다항식의 가중치 함수에 대하여 살펴본다. 1967년 Krall Sheffer에 의해 약직교 다항식을 가짐이 알려져 있었으나 직교성 여부에 대해서는 밝혀지지 않았다. 최근에 얻어진 결과를 이용하여 각 편미분 방정식이 직교 다항식을 해로 가질 조건을 알아보고 가중치 함수를 구한다. 이 문제는 30년 동안 미해결되었던 문제를 해결한 것이다. We consider the following set of partial differential equations which have orthogonal polynomials in two variables as solutions. In 1967, H. L. Krall and I. M. Sheffer considered the problem of classifying certain second-order partial differential equations having weak orthogonal polynomial systems of solutions. In this paper, we produce conditions for when these polynomials form an orthogonal polynomial sequence and we construct, under these conditions, a real-valued weight function for the correspond ing orthogonal polynomials by using polynomial killers in certain domain of the plane. This solves an open problem raised in 1967 by Krall and Sheffer.

The effect of solvent viscosity on the kinetic approach to determine cobalt-carbon bond dissociation energies

송병호,전무성 선문대학교 자연과학대학 2000 자연과학논총 Vol.3 No.-

(DH)_(2)Co^(m)(-CH_(2)C_(6)H_(5))(PR_(3))과(OEP) Co^(m)(-CH_(2)C_(6)H_(5))[P(CH_(3))_(2)(C_(6)H_(5))]의 열분해는 자유 라디칼 중간체인 TEMPO를 사용해서 toluene과 ethylene glycol하에서 연구했다. Co-c 결합의 균일분해에 대한 △H□은 ethylene glycol과 toluene상태에서 가장 큰 값인 4.2-6.0cal/mol 만큼의 차이가 균일하게 나타난다. 그러므로, transition-metal-carbo 합의 해리 에너지(BDE)를 측정할 때 더 높은 △H_(-1)□(4-6kcal/mol)의 수정값을 위해서는 일반적으로 사용하는 수용액이나 점도가 낮은 유기용매보다 ethylene glycol과 같은 높은 점도의 용매를 사용해야만 한다 The thermolysis of three alkylcobaloximes, (DH)_(2)Co^(m)(-CH_(2)C_(6)H_(5))(PR_(3)), where DH = dimethylglyoximato and PR_(3) = [P(Cyc-C_(6)H_(11))_(3)], or [P(C_(2)H_(5)) (C_(6)H_(5))_(2)], and one organocobalt porphyrin (OEP) Co^(m)(-CH_(2)C_(6)H_(5))[P(CH_(3))_(2)(C_(6)H_(5))], where OEP = 2,3,7,8,12,13,17,18-octaehtylporphyrinato dianion,)], was studied in toluene and ethylene glycol, using TEMPO(2,2,6,6-tetramethylpiperidine-l-oxyl) as the free radical trap. The △H□ for Co-C bond homolysis was found to be 4.2-6.0kcal/mol greater in ethylene glycol versus toluene. This difference in △H□ parallels the 4kcal/mol difference between the temperature dependence of the viscosity of ethylene glycol (6.8kcal/mol) and that of benzene (3.0kcal/mol). Therefore, when estimating transition-metal-carbon bond dissociation energies, (BDE), a higher correction for A △H_(-1)□ (4-6kcal/mol) must be used in high viscosity solvents (such as ethylene glycol) than the more commonly used 2kcal/mol for aqueous solutions and low viscosity organic solvents.

RNA에 결합하는 능력을 상실한 mutant hnRNP K단백질이 핵과 세포질을 왕복하는 활성에 미치는 영향

최미영 선문대학교 자연과학대학 2001 자연과학논총 Vol.4 No.-

Rotating flow of a stratified fluid contained in a circular cylinder with unstable temperature gradient imposed on the side wall of it has been numerically studied. The temperatures at the endwall disks are constant. The top disk of the container is colder than that of the bottom disk, as much as the temperature difference nΔT, (0≤n≤3). Flows in the vessel are driven by an impulsive rotation of the hot bottom disk with respect to the central axis of the cylinder. Flow details have been acquired. For this flow, the principal balance in the interior core is characterized by a relationship between the radial temperature gradient and the vertical shear in the azimuthal velocity. As the buoyancy effect becomes appreciable, larger portions of the meridional fluid transport are longcircuit from the bottom disk to the interior region via the side wall.

The study of the thermal decomposition of (benzyl)CoⅢOEP(THF)

Song, Byungho,Jun, Musung 선문대학교 자연과학대학 1998 자연과학대학 논문집 Vol.1 No.-

(benzyl)CoⅢOEP(THF)의 열분해는 45-63.0℃ 사이에서 다섯 개의 서로 다른 온도 영역에서 THF 용매내에서 실험했다. 변화된 이론은 측정되는 속도상수와 첨가되는 CoⅡOEP의 농도에서 나타난다. 안정한 라디칼 중간 상태인 TEMPO를 첨가하는 이러한 시스템은 분해하는 속도를 증가시킨다. 반응물 에 대한 실험을 통해서 l-benzyloxy-2,2,6,6-tetramethylpiperidine (크로마토그래피로 검출)에 의한 중간 상태의 유기생성물과 CoⅡOEP (UV-visible 분광기로 검출)에 대한 코발트 생성물을 발견했다. 선명한 흡수점은 열분해 곡선에서 발견했다. k_(obsd)^(-1) 대 [TEMPO]^(-1) 과 k_(obsd)^(-1) 대 [CoⅡOEP]의 도시는(benzyl)CoⅡOEP(THF)내에서 코발트-탄소 결합의 균등 분해에 의한 속도상수 k_(1)의 계산에 이용된다. k_(1)값의 독립적인 시험에 있어서 제한속도 (높은 농도의 TEMPO 그리고 CoⅡOEP를 첨가하지 않은 상태)는 서로 다른 다섯 개의 온도 영역에서 결장했다. In k_(1)/T 대 1/T의 Erying plot로부터 열분해에 의한 ΔH□ 값은 25.9kcal/mol이고 ΔS□ 값은 2.18 엔트로피 단위로 계산된다. The thermal decomposition of (benzyl)CoⅢOEP(THF) (OEP=7,8,12,13,17,18-octaethyl porphyrinato, THF=tetrahydrofuran) was examined in THF at five different temperatures in the range of 45.0- 63.0℃. An inverse dependence was seen between the observed rate constant and the concentra- tion of CoⅡOEP added. Addition of the stable radical trap TEMPO (2,2,6,6-tetramethyl piperidyl-N-Oxide), to the system increased the rate of decomposition. Examination of the reaction products showed the organic trapping product to be l-benzyloxy-2,2,6,6-tetramethyl piperidine(detected by gas chromatography) and the cobalt product to be CoⅡOEP (detected by UV-visible spectro- photometry). Clean isosbestic points were observed over the course of the thermal decomposition. Plots of k_(obsd)^(-1) versus [TEMPO]^(-1) and k_(obsd)^(-1) versus [CoⅡOEP] gave intercepts that were used to calculate k1, the rate constant for homolysis of the cobalt-carbon bond in (benzyl)CoⅡOEP- (THF). As an independent test of the value of k_(1), the limiting rate (at high TEMPO concentra- tion and no CoⅡOEP added) was determined at each of the five temperatures. From the Eyring plot of In k_(1)/T versus 1/T, the ΔH□ for the thermal decomposition was calculated to be 25.9kcal /mol and the Δs□ to be 2.18 entropy units.

Studies of STM and AFM images of graphite surface structure

김호섭 선문대학교 자연과학대학 2000 자연과학논총 Vol.3 No.-

주사형터널현미경과 원자현미경에 의하여 측정된 그라파이트 표면분석에 관한 해석의 기본적인 문제점이 대두되어왔다. 그라파이트 표면은 6개의 탄소원자로 구성된 Hexagonal 구조을 이루고 있으나, 일반적으로 측정된 그라파이트 표면의 STM과 AFM 이미지는 두 개의 탄소원자가 하나의 이미지 스팟으로 보이는 tigonal symmetry을 보이고 있다. 본 논문에서는 1A 이하의 분해능으로 그라파이트 표면을 측정하여 제시한 이론적인 가설 검토한다. A fundamental problem with the interpretation of STM and AFM images of graphite has existed since their inception. The experimental and theoretical hypotheses have been considered and a resolution of the problem has been developed. Unprecedented resolving power, greater than I A, has confirmed our hypothesis and yields atomically resolved STM and AFM images which correctly correlated with the known hexagonal structure of the graphite surface; whereas common images with trigonal symmetry represent two unresolved carbon atoms per image spot.

Fabrication of Volcano-type SI-tip using Proximity Printing

Choi, S.S. 선문대학교 자연과학대학 1998 자연과학대학 논문집 Vol.1 No.-

The volcano-type field-emission tip arrays have been fabricated on the silicon substrate using proximity pattern printing. A 3000A˚ silicon dioxide was thermally grown for etching and patterning tip-masks and the positive photoresist coating was followed. During the exposure process. The alignment gap between the mask and the sample was adjusted to 10 ㎛. Upon 9 seconds exposure of the ultra violet lights with combinations of g-line (435 nm), h-line(405 nm), and i-line(365 nm), the donut-type ring patterns dependent on the mask pattern size were observed on the sample. The inner diameters of the ring after the exposure are found to be dependent upon the gap between the mask and the sample, the size of the mask pattern, and the exposure time. For the diameters greater than 2.5 ㎛, the ring patterns have not been observed. The inner diameter of the ring pattern for 1.4 ㎛ mask pattern is found to be ~ 1.25㎛, while the outside of the diameter is found to be ~ 2.5 ㎛ by scanning electron microscopy(SEM). The isotropic reactive ion etching(RIE) procedure were performed using a SF_(6). The inner-diameter of the volcano-type tip was found to be ~ 1㎛.