A Further Study on the NMR Chemical Shift for a 3d^1 System in a Strong Crystal Field Environment of Octahedral Symmetry with a Threefold Axis of Quantization

Ahn, Sangwoon,Lee, Kee Hag 圓光大學校 基礎自然科學硏究所 1987 基礎科學硏究誌 Vol.6 No.3

The hamiltonian representing the various interaction in a strong crystal field environment of octahedral symmetry may be expressed as and when a threefold axis is chosen as the axis of quantization.

Bonding Effect on the Pseudo Contact NMR Shift for a d^1 System in the Strong Crystal Field of Tetragonal Symmetry

Ahn, Sangwoon,Park, Euishu,Ko, Jeong Soo 全北大學校 1982 論文集 Vol.24 No.-

non-multipole 전개방법을 사용하여 직각이동대칭을 갖은 센결정장에서 d^1전자계의 pseudo contact NMR 이동에 대한 화학결합의 영향을 고찰하였다. hyperfine integrals을 spherical harmonics 및 지름적분으로 나타내었으며 행열요소를 analytical form으로 Table에 나타내었다. NMR이동에 대한 화학결합의 영향이 R=0.15~0.30nm 범위에서 특히 크게 나타남을 발견하였다. 이론적으로 계산한 자기모멘트의 비등방성(magnetic anisotropy)으로부터 dipolar shift를 계산하였으며 dipolar shift가 NMR 이동에 크게 기여함을 발견하였다.

Effects of an Elecric Field on the Magnetic Moment and the NMR Shift for a d^1 System in a Strong Crystal Field of O Symmetry

Ahn, Sangwoon 全北大學校 1982 論文集 Vol.24 No.-

z축방향으로 전장을 적용하였을 때 센결정장에서 d^1 전자계에 대한 지기모멘트 및 NMR 이동에 대한 전장의 영향을 고찰하였다. 계산한 자기모멘트 값은 전장의 영향을 크게받지 않았다. 그러나 전장의 세기가 증가 함에 따라 z축방향의 NMR이동 값은 크게 증가하여 한계 값에 접근하였지만 x 및 y 축방향의 NMR이동값은 계속감소하였다. 이 결과는 d^1 전자계의 팔면체결정장이 z축방향으로 적용한 전장으로 인하여 일그러졌음을 암시한다.

Calculation of the NMR Chemical Shift for a 3d^2 System in a Strong Crystal Field of Trigonal Symmetry with a Threefold Axis of Quantization

AHN, SANGWOON,LEE, KEE HAG 圓光大學校 基礎自然科學硏究所 1987 基礎科學硏究誌 Vol.6 No.3

Using the nonmultipole expansion method, the NMR chemical shift arising from the electron orbital angular momentum and the electron spin dipolar-nuclear spin angular momentum interaction for a 3d^2 system in a strong crystal field environment of trigonal symmetry, when a threefold axis is chosen as the axis of quantization, is calculated as a function of the distance of the NMR nucleus from the paramagnetic ion, and temperature. From a general expression which is derived, all the multipolar terms are determined and the exact solution of ΔB/B(ppm) is compared with the multipolar terms. The major contribution to ΔB/B(ppm) arises from the 1/R^5 term but the other terms are certainly significant. An analysis of temperature dependence shows that, although the dominant contribution to ΔB/B(ppm) is th 1/T^2 term, the 1/T term contributes markedly.

알코올과 요드사이의 분자 착물에 대한 분광학적인 연구 (가시부에서)

안상운,고정수 全北大學校 文理科大學 1977 論文集 Vol.6 No.-

이소옥탄매질에서 알코올과 요드사이의 분자착물에 대한 분광학적인 연구를 하였다. 이소옥탄 용액에서 요드분자의 흡수띠가 알코올농도가 증가함에 따라 단파장쪽으로 이동하였고 490mu에서 isosbestic point가 나 났다. 이러한 사실로 보아 알코올과 요드사이에 1:1 분자착물이 형성되었다고 생각하였다. Bensi-Hildebrand 방정식과 Scott 방정식을 사용하여 요드와 알코올 분자착물 생성반응의 평셩상수를 계산하였다. logK_c와 u 사이에 다음과 같은 일차함수식이 성립하였다. logK_c=mu+b 여기에서 m=-2.5 A visible spectroscopic study has been performed on the molecular complexes between alcohol and iodine in isooctane medium. The absorption band of iodine molecule in isooctane was shifted to blue side as the concentration of alcohol was increased and the isostic point was found at 490 mu. This fact indicates that 1:1 molecular complexes are formed between alcohol and iodine. The equilibrium constants for the formation of alcohol-I_2 complexes were calculated by Bensi-Hildebrand equation and Scott equation. The following linear relation between log K_c and u is obtained from the plot of log K_c vs u: log K_c=mu+b where m=-2.5

Metal Anions의 Polymerization에 關한 硏究(Ⅱ) : Orthotungstate ions의 Polynucleation Polynucleation of Orthotungstate Ion

안상운 全北大學校 1972 論文集 Vol.14 No.-

The polynucleation reactions occurred, when orthotungstate solutions was acidified with perchloric acid, have been investigated 30℃ in 1 m NaClO_4 medium, using glass electrode. Tungstate ion was first polynuclearized to hexatungstate ion (Hw_6O_21^-5) but hexatungstate ion formed was found to further polynuclearize to dodecatungstate ion(w_12O_41^-10) at more concentrated solutions and HW_12O_40^-7 ion at higher acidity. The following equilibrum constants could be assigned to the polynucleation reactions listed below; 7H^++6WO_4^-2=HW_6O_21^-5+3H_2O log k_6, 7=56.24±0.15 14^++12WO_4^-2=W_12O_41^-10+7H_2O log K_12, 14=124.47±0.10 17H^++12WO_4^-2=HW_12O_40^-7+8H_2O log K_12,17=126.36

다중텅스텐산이온 생성반응의 평형상수에 대한 용매의 영향 : 2M-KCl 용액에서

안상운,박영수 全北大學校 文理科大學 1977 論文集 Vol.6 No.-

5~20%에 에타놀을 포함하는 2M KCl 용액에서 헥사텅스텐산 이온과 양성자화된 헥사텅스텐 산이온이 생성되었다. 헥사텅스텐산 이온과 양성자화된 헥사텅스텐산이온 생성반응의 자유에너지 변화는 에타놀의 함량이 증가함에 따라 감소하였다. 그러나 같은 반응의 벤트로피 변화는 에타놀의 함량의 비례해서 증가하였다. 헥사텅스텐산이온 및 양성자화된 헥사텅스텐산 이온 생성반응의 엔탚피변화는 5~20% 에타놀을 포함하는 2M kCl 용액에서 거의 일정하였다. 헥사텅스텐산이온과 칼륨이온 사이에 Bjerrum 꼴의 이온회합에 대한 에타놀의 영향을 고찰하기 위하여 에타놀을 포함하는 2M KCl 용액에 대하여 log K_c 에 대한 1/D의 그라프를 도시 하였을 때 평형온도 30~40℃에서 다음과 같은 직선관계식을 얻었다. log K_c=constant+?? log K_c vs 1/D 그라프의 기울기로 부터 계산한 평균 "m"의 값은 약 4.5이었다. The hexatungstate ion(HW_5O^5_21) and the protonized forms of hexatungate ion(H_2W_6C^3_21) are formed in 2M-KCI solution containing 5~20% ethyl alcohol. The free energy changes for the formation of hexatungstate ion and the protonized forms of hexatungstate ion decrease as the content of ethyl alcohol is increased, but the entropy changes of the above reaction increase in proportion to the content of ethyl alcohol in 2M-KCl solution. The enthalpy changes for the formation of hexatungstate ion and the protonized reactios of hexatungstate ion are nearly constant in 2M-KCl solution contatining 5~20% ethyl alcohol. When logK_c is polotted against 1/D for 2M-KCl aqueous ethyl alcohol solution to investigate the effect of ethyl alcohol on the ion-association of Bjerrum thpe between hextungstate ion and potassium ion the following linear relation is obtained at the equilibrium temperature of 30-40℃, log K_c=const.+?? The average of 'm' values calculated from the slope of log K_c vs 1/D is about 4.5,

A mathematical model for the 3d location estimation of 2D echocardiography data

Ahn, Chi Young,Yun, Sangwoon Elsevier 2019 APPLIED MATHEMATICS LETTERS Vol.88 No.-

<P><B>Abstract</B></P> <P>The recovery of 3D left ventricle(LV) shape using 2D echocardiography is very attractable topic in the field of ultrasound imaging. In this paper, we propose a mathematical model to determine the 3D position of LV contours extracted from multiple 2D echocardiography images. We formulate the proposed model as a non-convex constrained minimization problem. To solve it, we propose a proximal alternating minimization algorithm with a solver <I>OPTI</I> for quadratically constrained quadratic program. For validating the proposed model, numerical experiments are performed with real ultrasound data. The experimental results show that the proposed model is promising and available for real echocardiography data.</P>

A study on the 3D position estimation of ventricular borders extracted from 2D echocardiography data

Ahn, Chi Young,Yun, Sangwoon Elsevier 2018 COMPUTERS & MATHEMATICS WITH APPLICATIONS - Vol.75 No.4

<P><B>Abstract</B></P> <P>We study on the reconstruction of 3D left ventricle(LV) using only 2D echocardiography data and information on apical long-axis views. Especially, this paper focuses on determining the 3D position of LV contours extracted from 2D echocardiography images. First we mathematically model the relationship between LV contours on the apical views and their corresponding 3D positions. The relationship is expressed as a linear equation in which the right-hand side is the measured data consisting of all the LV contour points on each view and the coefficient matrix is an unknown matrix that transforms the unknown 3D positions into contour points on their related apical view, with distance and orthogonality conditions on the coefficient matrix and the 3D positions. Next we consider a non-convex constrained minimization problem to determine the coefficient matrix and the 3D positions. To solve this minimization problem, we adopt two block coordinate descent method with a solver in <I>OPTI</I> for quadratically constrained quadratic program. For validating the proposed method, some numerical experiments are performed with synthetic data. The experimental results show that the proposed model is promising and available for real echocardiographydata.</P>

사면체 및 사각형 $[M(II)N_2S_2]$ 형태 착물의 쌍극자 모멘트의 계산 [M(II) = Ni(II), Co(II), Cu(II) 또는 Zn(II)]

안상운,Ahn Sangwoon 대한화학회 1979 대한화학회지 Vol.23 No.1

사각형 및 사면체 $[M(II)N_2S_2]$형태 착물의 쌍극자모멘트를 spherical harmonics의 전개방법에 의하여 계산하였다. [M(II) = Co(II), Ni(II), Cu(II) 또는 Zn(II)]. 이들 착물에 대한 쌍극자모멘트의 계산치가 실험치 범위안에 들었다. 계산한 쌍극자모멘트와 자기적 성질을 기초로하여 벤젠용액에서 이들 착물에 대한 가능한 구조를 고찰하였다. The dipole moments for square planar and tetrahedral $[M(II)N_2S_2]$ type complexes are calculated, using the expansion method for spherical harmonics [M(II) = Co(II), Ni(II), Cu(II) or Zn(II)]. The calculated values of the dipole moments for these complexes are in the range of the experimental values. The possible structures for these complexes in benzene solution are discussed on the basis of the calculated dipole moments and the the magnetic properties.