• Journal of the Korean Chemical Society
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• v.50 no.4
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• pp.291-297
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• 2006

The equilibrium structures, relative energies and NBO analyses for the possible conformations and transition states which can exist on the internal rotation of CPDFB and CPCFB molecules have been investigated using DFT and ab initio methods with various basis sets. The interaction between bonding orbital ((C1-C3, C2-C3)) and antibonding orbital (n*(B9) and *(B9-Cl11)) was the main characteristic hyperconjugation in both molecules. In addition, the stabilization energy of CPDFB was 6.63kcal/mol and that of CPCFB was 6.97(E-form)/6.79(Z-form) kcal/mol for each conformation. The rotational barriers by internal rotation of BF2- and BFCl- functional groups were evaluated to be 5.3~6.7kcal/mol and 5.7~6.5kcal/mol respectively, which showed good agreement with the experimental values reported by previous dynamic NMR study. Finally, Z-form was more stable than E-form by 0.2 kcal/mol in CPCFB molecule and therefore Z-form was confirmed as global minimum.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.125-130
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• 2007

Single-phase is used widely power of field of appliance because can use commercialized power directly without power transform. Specially, because condenser nu-drive style single-phase induction motor efficiency is excellent, and most suitable in embodiment as economical. It is established true that method by crossing self-discipline and method by revolving magnetic field are interpretation of net single-phase induction motor, but method to calculate electric motor inside proper move in existent theory or method is some complex. That arbor in the law of circuit constant that combine equivalent circuit law with numerical analysis law according to development of the latest computer or microprocessor is suggested and does the calculation processing fast and correct. In this paper, measurement wishes to present method that calculate after calculate digital measurement that measures correctly and measures impossible the first and the second leakage reactance and no-load test locked-rotor test, DC test and resistance measurement of stator winding in circuit parameter calculation program that is had for MatLab program individually in single-phase power.

• Journal of the Korean Chemical Society
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• v.64 no.6
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• pp.350-353
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• 2020

The validity of the calculation method based on the local mode in hydrogen-bonded water molecules was investigated by comparing the frequencies of the local and normal modes of OH stretching vibration in water molecules. By calculating a monomer, dimer, and trimer of water molecules using a quantum chemical ab initio theory, we examined how the frequencies of the local and normal modes and the anharmonicity of local modes vary with molecular cluster size. It was shown that, as the number of molecules increases from monomer to trimer, the anharmonicity of OH bonds increases and the difference between local and normal mode frequencies decreases. This confirms that local-mode-based calculations that can easily handle the anharmonicity can be appropriate for the calculation of the OH stretching frequency of water molecules in the condensed phase.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.123-129
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• 1997

In order to consider the reduced mass effects on the out-of-plane ring inversion vibration of 1,3-CHD, the vector-based computer program has been written and the kinetic energy expansion function for the large amplitude ring inversion vibration has been calculated using this program. The structural parameters for the calculations have been determined from the ab initio HF/6-31G** calculation. The potential energy function for the out-of-plane ring inversion vibration of 1,3-CHD has been determined from the kinetic energy expansion function and previously reported low-frequency Raman data. The vibrational Hamiltonian calculation including kinetic energy expansion function made it possible to determine the more reliable out-of-plane potential energy function for the ring inversion of 1,3-CHD.

• Journal of the Korean Chemical Society
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• v.59 no.5
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• pp.387-396
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• 2015

The DFT and ab initio calculations have been performed to elucidate hydrogen interaction of HOOO-(H₂O)_n (n=1~5) clusters. The optimized geometries, harmonic vibrational frequencies, and binding energies are predicted at various levels of theory. The trans conformer of HOOO monomer is predicted to be thermodynamically more stable than cis form at the CCSD(T) level of theory. For HOOO-(H₂O)_n clusters, the geometries are optimized at B3LYP/aug-cc-pVTZ and CAM-B3LYP/aug-cc-pVTZ levels of theory. The binding energy of HOOO-H₂O cluster is predicted to be 6.05 kcal/mol at the MP2//CAM-B3LYP/ aug-cc-pVTZ level of theory after zero-point vibrational energy (ZPVE) and basis set superposition error (BSSE) correction. The average binding energy per H₂O is increased according to adding a H₂O moiety in HOOO-(H₂O)_n clusters up to 7.2 kcal/mol for n=5.

• Journal of the Korean Chemical Society
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• v.61 no.6
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• pp.328-338
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• 2017

The density functional theory(DFT) and ab initio calculations have been applied to investigate hydrogen interaction of $H_2O_3(H_2O)_n$ clusters(n=1-5). The structures, IR spectra, and H-bonding energies are calculated at various levels of theory. The $trans-H_2O_3$ monomer is predicted to be thermodynamically more stable than cis form at the CCSD(T)/cc-pVTZ level of theory. For clusters, the geometries are optimized at the MP2/cc-pVTZ level of theory. The binding energy of $H_2O_3-H_2O$ cluster is predicted to be -6.39 kcal/mol at the CCSD(T)//MP2/cc-pVTZ level of theory after zero-point vibrational energy (ZPVE) and basis set superposition error (BSSE) correction. This result implies that $H_2O_3$ is a stronger proton donor(acid) than either $H_2O$ or $H_2O_2$. The average binding energies per $H_2O$ are predicted to be 8.25 kcal/mol for n=2, 7.22 kcal/mol for n=3, 8.50 kcal/mol for n=4, and 8.16 kcal/mol for n=5.

• The KIPS Transactions:PartB
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• v.17B no.5
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• pp.363-374
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• 2010

In this paper, we propose the method for extracting Homogeneity Threshold($H_T$) and for segmenting homogeneous regions by USRG(Unseeded Region Growing) with $H_T$. The $H_T$ is a criterion to distinguish homogeneity in neighbor pixels and is computed automatically from the original image by proposed method. Theoretical background for proposed method is based on the Otsu's single level threshold method. The method is used to divide a small local part of original image int o two classes and the sum($\sigma_c$) of standard deviations for the classes to satisfy special conditions for distinguishing as different regions from each other is used to compute $H_T$. To find validity for proposed method, we compare the original image with the image that is regenerated with only the segmented homogeneous regions and show up the fact that the difference between two images is not exist visually and also present the steps to regenerate the image in order the size of segmented homogeneous regions and in order the intensity that includes pixels. Also, we show up the validity of proposed method with various results that is segmented using the homogeneity thresholds($H^*_T$) that is added a coefficient ${\alpha}$ for adjusting scope of $H_T$. We expect that the proposed method can be applied in various fields such as visualization and animation of natural image, anatomy and biology and so on.

• Analytical Science and Technology
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• v.18 no.4
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• pp.309-319
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• 2005

The adsorption characteristics of gaseous molecules on the carbonaceous adsorbent have been investigated at various temperature and pressure with different pore sizes using Grand Canonical Monte Carlo (GCMC) simulation method. The geometrical parameters and spectroscopic properties of adsorbates have been computed using density functional theory (DFT). At higher temperatures is the adsorption amount of adsorbates is decreased due to their vaporization. Considering the pore size effect, the adsorption characteristic depends on the adsorbate size, polarity and interaction between adsorbates, etc. At all cases employed in this study, the adsorption amount of adsorbates on the carbonaceous adsorbent is increased in the order $NH_3$ < $H_2S$ < $CH_3SH$, and this result is qualitatively in good agreement with the experimental observation.

• Proceedings of the KOR-KST Conference
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• 1998.10a
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• pp.11-20
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• 1998

정적 통행배분모형은 도로 건설 등 공급부문에의 적용은 가능하나 통행량 및 혼잡의 시간적 공간적 변화를 고려하지 못하여 수요관리에서는 교통량 및 비용에 대한 관측치와 모형의 결과치가 상이한 문제가 있다. 이에 동적배분모형의 다양한 접근방법이 시도되고 있는데 그 중 Simulation기법을 개발하고자 하였다. 모형은 개별차량의 시공간상 움직임을 포현하고자 절대시간이 가장 이른 차량순으로 시뮬레이션을 함으로써 선입선출(FIFO)을 가능하게 하였다. 각 차량별 지체시간의 계산은 대기행렬 이론을 기초로 한 누적곡선법을 적용하여 도출하였다. 개별차량 Simulation은 시간축으로 확장된 연속류 Network상에서 각 차량의 도착 및 출발할 노드와 시간대를 결정하면 모든 지점에서 누적도착, 출발곡선을 그릴 수 있으며 이를 통해 도로구간에 있어 시간대별 통행시간, 밀도, 속도 등을 파악할 수 있다. 또한 합류부의 용량와 와해현상과 분류부의 용량변화현상 제약 및 Queue길이 제약이 이루어지도록 하였다. 개발된 모형의 검증은 영동대교 북단 강변도로 진출입부 자료를 실측하여 사용하였다. 모형은 합류부 용량와해의 적용 전과 후의 결과를 각각 실측치와 비교하였다. 용량와해현상을 적용한 모형에서 MAPE 10%미만의 우수한 예측력을 보였다. 이는 누적곡선을 이용한 Simulation모형이 현실에 가까움을 의미하는 것이며, 합류부 용량와해현상의 관계식을 보다 정교하게 도출하고 분류부에도 이를 적용한다면 모형의 예측력은 더욱 향상될 것으로 보인다.

• Journal of Korean Society of Steel Construction
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• v.13 no.5
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• pp.567-575
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• 2001

In order to consider statistical properties of probability variables used in the structural analysis the conventional approach using the safety factor based on past experience usually estimated the safety of a structure Also the real structures could only be analyzed with the error in estimation of loads material characters and the dimensions of the members. But the errors should be considered systematically in the structural analysis Safety of structure could not precisely be appraised by the traditional structural design concept Recently new aproach based on the probability concept has been applied to the assessment of structural safety using the reliability concept Thus the computer program by the Probabilitstic FEM is developed by incorporating the probabilistic concept into the conventional FEM method. This paper estimated for the reliability of a plane stress structure by Advanced First-Order Second Moment method using von Mises, Tresca and Mohr-Coulomb failure criterions. Verification of the reliability index and failure probability of attained by the Monte Carlo Simulation method with the von Mises criterion were same as PFEM, but the Monte Carlo Simulation were very time-consuming. The variance of member thickness and load could influence the reliability and failure probability most sensitively among the design variables from the results of the parameter analysis. The proper failure criterion according to characteristic of materials must be used for safe design.