• Bulletin of the Korean Chemical Society
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• 제19권10호
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• pp.1084-1090
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• 1998

The oxidation of triphenylphosphine by [(tpy)(phen)RuⅣ(O)]2+ and [(bpy)(p-tert-butylpy)RuⅣ(0)]2+ (tpy is 2,2': 6',2"-terpyridine, phen is 1,10-phenanthroline, bpy is 2,2'-bipyridine, and p-tert-butylpy is para-tertbutylpyridine) in CH3CN has been studied. Experiments using 18O-labeled complex show the oxyl group transfer from [RuⅣ=O]2+ to triphenylphosphine occured quantitatively within experimental error. Kinetic data were fit to a second-order for [RuⅣ=O]2+ and [PPh3]. The initial product, [RuⅡ-OPPh3]2+, was formed as an observable intermediate and then underwent slow solvolysis. The reaction proceeded as endothermic in activation enthalpy and a decrease in activation entropy. The oxidative reactivity of four representative ruthenium mono-oxo oxidants against triphenylphosphine was compared. These systems have been utilized as electrochemical oxidative catalysts.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1450-1463
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• 2019

The problem towards crowd behavior recognition in a serious clustered scene is extremely challenged on account of variable scales with non-uniformity. This paper aims to propose a crowed behavior classification framework based on a transferring hybrid network blending 3D res-net with inception-v3. First, the 3D res-inception network is presented so as to learn the augmented visual feature of UCF 101. Then the target dataset is applied to fine-tune the network parameters in an attempt to classify the behavior of densely crowded scenes. Finally, a transferred entropy function is used to calculate the probability of multiple labels in accordance with these features. Experimental results show that the proposed method could greatly improve the accuracy of crowd behavior recognition and enhance the accuracy of multiple label classification.

• Korean Chemical Engineering Research
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• 제44권5호
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• pp.505-512
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• 2006

직경이 0.102 m이고 높이가 2.5 m인 액체-입자 swirling(나선)흐름 유동층에서 유동 입자의 흐름 및 열전달 특성을 고찰하였다. 액체유속($U_L$), 유동 입자의 크기($d_p$) 그리고 연속상인 액체의 나선 유도흐름 액체량의 비($R_s$)가 유동층 내 유동입자의 체류량 유동층 내부 열원과 유동층간의 총괄 열전달 계수에 미치는 영향을 검토하였다. 액체-입자 나선흐름 유동층에서 입자 체류량은 입자의 크기와 나선유도흐름 액체량의 비가 증가함에 따라서 증가하였으나, 액체유속의 증가에 따라서는 감소하였다. 유동층 내부에서 나선 유도 흐름 액체량의 비가 0.1~0.3인 경우에 유동 입자의 국부체류량은 유동층 중심부에서 큰 값을 나타내었으나, $R_s$의 값이 0.5일 때는 반경 방향 입자 체류량은 거의 균일한 분포를 보이며, $R_s$의 값이 0.7일 때는 유동층 중심부의 입자 체류량이 상대적으로 감소하는 경향을 나타내었다. 유동층 내부열원과 유동층간의 열전달 특성은 열원 표면과 유동층간의 온도차 요동 자료의 위상공간 투영과 kolmogorov 엔트로피 해석으로 고찰할 수 있었으며, 나선 유도 흐름 액체량의 비($R_s$)가 0.1에서 0.5까지 증가할수록 온도차 요동 자료의 위상공간 투영은 점점 안정되고 규칙성이 증대되는 상태를 나타내고, kolmogorov 엔트로피 값은 감소하는 경향을 나타내었다. 열원 표면과 유동층간의 온도차 요동 자료의 kolmogorov 엔트로피 값은 액체의 유속이 증가함에 따라 최대값을 나타내었다. 열원과 유동층간의 총괄 열전달 계수는 액체유속, 층공극률, 나선 유도 흐름 액체량의 비가 증가함에 따라서 최대값을 나타내었으며, 유동 입자의 크기가 증가함에 따라 증가하였다. 내부 열원과 유동층간의 총괄 열전달 계수가 최대값을 나타낼 때의 액체의 유속 조건에서 온도차 요동자료의 kolmogorov 엔트로피의 값도 최대값을 나타내었다. 액체-입자 나선흐름 유동층에서 입자 체류량과 열전달 계수를 무차원군의 상관식으로 나타낼 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1246-1250
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• 2005

We have evaluated the hydroxyl group-solvent specific interactions by using a Lichrosorb RP18 stationary phase and by measuring the retention data of carefully selected solutes in 50/50, 60/40, 70/30, 80/20, and 90/10(v/v%) methanol/water eluents at 25, 30, 35, 40, 45, and 50 ${^{\circ}C}$. The selected solutes are 3 positional isomers of phenylpropanol, that is, 1-phenyl-1-propanol, 1-phenyl-2-propanol, and 3-phenyl-1-propanol. There exist clear discrepancies in ${\Delta}H^o$ (solute transfer enthalpy from the mobile to the stationary phase) and $T{\Delta}S^o$ (solute transfer entropy) among positional isomers. The difference in ${\Delta}H^o$ and $T{\Delta}S^o$ between secondary alcohols (1-phenyl-1-propanol and 1-phenyl-2-propanol)is negligible compared to the difference between the primary alcohol (1-phenyl-3-propanol) and secondary alcohols. The $T{\Delta}S^o$ values of 3-phenyl-1-propanol are close to those of butylbenzene while the $T{\Delta}S^o$ values of secondary alcohols are close to those of propylbenzene. The difference in ${\Delta}{\Delta}H^o$ (specific solute-mobile phase interaction enthalpy) between the primary alcohol and the secondary alcohol decreases with increase of methanol content in the mobile phase. A unique observation is an extremum for 1-phenyl-3-propanol in the plot of $T{\Delta}{\Delta}S^o$ vs. methanol volume %. The positive sign of $T{\Delta}{\Delta}S^o$ of 3-phenyl-1-propanol implies that the entropy of 3-phenyl-1-propanol is greater than that of the hypothetical alkylbenzene (the same size and shape as phenylpropanol) in the mobile phase.

• 한국해안해양공학회지
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• 제2권3호
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• pp.119-127
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• 1990

불규칙 파랑의 파향스펙트럼 추정법에 대하여 고찰하였다. 파향스펙트럼 추정이론의 근간은 Longuet-Higgins et al.(1963)이 제시한 방법으로 현재 많이 이용되고 있으나 추정정도가 매우 낮은 것으로 나타났다. 그리고 파향스펙트럼을 ［0, 2$\pi$］에서의 확률밀도함수로 간주하고 Entropy 법칙을 응용한 Kobune et al.(1986)의 최대 엔트로피법 (MEM)은 Longuet-Higgins et al.의 방법 (LHM)에 비해 파향의 분석능이 매우 좋은 것으로 나타났다. 특히 MEM은 파향스펙트럼이 Delta 함수민 경과에는 그 파향스펙트럼을 정확하게 추정하며, 단봉형 스펙트럼의 경과에도 Mitsuyasu의 방향분산계수(spreading coefficient)가 5 이상이면 정도가 매우 좋은 것으로 나타났다. 또한, 쌍봉형 파향스펙트럼의 경과에는 두 peak를 이루는 파향의 각도차가 클수록 분해능이 양호하며, peak의 첨예도(peakedness)가 큰 쪽이 평활화(smoothing)되어 이 부분의 에너지 일부가 첨예도가 작은 peak쪽으로 이동하는 것을 알 수 있었다. 한편 LHM은 쌍봉형의 경과에도 단봉형으로 추정하는 경향이 뚜렷하며, 계산시간이 빠른 점을 제외하면 MEM에 비해 분해능이 매우 뒤떨어지는 방법이라 할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제33권3호
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• pp.1037-1041
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• 2012

The nucleophilic substitution reactions of (2R,4R,5S)-(+)-2-chloro-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidine 2-sulfide (3) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $5.0^{\circ}C$. The anilinolysis rate of 3 involving a cyclic five-membered ring is considerably fast because of small negative value of the entropy of activation (${\Delta}S^\neq=-2cal\;mol^{-1}\;K^{-1}$) over considerably unfavorable enthalpy of activation (${\Delta}H^\neq=18.0\;kcal\;mol^{-1}$). Great enthalpy and small negative entropy of activation are ascribed to sterically congested transition state (TS) and bulk solvent structure breaking in the TS. A concerted $S_N2$ mechanism with a backside nucleophilic attack is proposed on the basis of the secondary inverse deuterium kinetic isotope effects, $k_H/k_D$ < 1.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4347-4351
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• 2011

The nucleophilic substitution reactions of ethylene phosphorochloridate (2) with X-pyridines are investigated kinetically in acetonitrile at $-20.0^{\circ}C$. The free energy correlations for substituent X variations in the nucleophiles exhibit biphasic concave upwards with a break point at X = 3-Ph. Unusual positive ${\rho}_X$ (= +2.49) and negative ${\beta}_X$ (= -0.41) values are obtained with the weakly basic pyridines, and rationalized by the isokinetic relationship with isokinetic temperature at $t_{ISOKINETIC}=6.6^{\circ}C$. The pyridinolysis rate of 2 with a cyclic five-membered ring is forty thousand times faster than its acyclic counterpart (3: diethyl chlorophosphate) because of great positive value of the entropy of activation of 2 (${\Delta}S^{\neq}$ = +49.2 eu) compared to negative value of 3 (${\Delta}S^{\neq}$ = -44.1 eu) over considerably unfavorable enthalpy of activation of 2 (${\Delta}H^{\neq}=28.4\;kcal\;mol^{-1}$) compared to 3 (${\Delta}H^{\neq}=6.3\;kcal\;mol^{-1}$). Great enthalpy and positive entropy of activation are ascribed to sterically congested transition state (TS) and solvent structure breaking in the TS. A concerted mechanism involving a change of nucleophilic attacking direction from a frontside attack with the strongly basic pyridines to a backside attack with the weakly basic pyridines is proposed.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.270-274
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• 2012

The nucleophilic substitution reactions of 1,2-phenylene phosphorochloridate (1c) with X-pyridines are investigated kinetically in acetonitrile at $-25.0^{\circ}C$. The free energy correlations for substituent X variations in the nucleophiles exhibit biphasic concave upwards with a break point at X = 3-Ph. The pyridinolysis rate of 1c with a cyclic five-membered ring is $2.70{\times}10^5$ times faster than its acyclic counterpart (1a: phenyl ethyl chlorophosphate) because of great positive value of the entropy of activation of 1c (${\Delta}S^{\neq}$ = +26 eu) compared to negative value of 1a (${\Delta}S^{\neq}$= -24 eu) over considerably unfavorable enthalpy of activation of 1c (${\Delta}H^{\neq}=20.5kcal\;mol^{-1}$) compared to 1a (${\Delta}H^{\neq}=12.7kcal\;mol^{-1}$). Great enthalpy and positive entropy of activation are ascribed to sterically congested transition state (TS) and solvent structure breaking in the TS. A concerted mechanism involving a change of nucleophilic attacking direction from a frontside attack with the strongly basic pyridines to a backside attack with the weakly basic pyridines is proposed on the basis of greater selectivity parameters (${\rho}_X$ = -1.99 and ${\beta}_X$ = 0.41) with the strongly basic pyridines compared to those (${\rho}_X$ = -0.42 and ${\beta}_X$ = 0.07) with the weakly basic pyridines.

• BMB Reports
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• 제31권4호
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• pp.307-327
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• 1998

Cytochrome c peroxidase (CcP) is a yeast mitochondrial enzyme which catalyzes the reduction of hydrogen peroxide to water using two equivalents of ferrocytochrome c. The CcP/cytochrome c system has many features which make it a very useful model for detailed investigation of heme protein structure/function relationships including activation of hydrogen peroxide, protein-protein interactions, and long-range electron transfer. Both CcP and cytochrome c are single heme, single subunit proteins of modest size. High-resolution crystallographic structures of both proteins, of one-to-one complexes of the two proteins, and a number of active-site mutants are available. Site-directed mutagenesis studies indicate that the distal histidine in CcP is primarily responsible for rapid utilization of hydrogen peroxide implying significantly different properties of the distal histidine in the peroxidases compared to the globins. CcP and cytochrome c bind to form a dynamic one-to-one complex. The binding is largely electrostatic in nature with a small, unfavorable enthalpy of binding and a large positive entropy change upon complex formation. The cytochrome c-binding site on CcP has been mapped in solution by measuring the binding affinities between cytochrome c and a number of CcP surface mutations. The binding site for cytochrome c in solution is consistent with the crystallographic structure of the one-to-one complex. Evidence for the involvement of a second, low-affinity cytochrome c-binding site on CcP in long-range electron transfer between the two proteins is reviewed.

• 대한화학회지
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• 제32권6호
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• pp.513-519
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• 1988

헥사메틸벤젠과 1,3,5-트리니트로벤젠과의 사이에 전하이동착물의 안정도에 미치는 압력과 온도의 영향을 사염화탄소용액내에서 분광광도법으로 연구하였다. 압력은 1, 200, 500, 1000, 1400 bar. 온도는 25, 40, $50^{\circ}C$사이에서 측정하였다. 착물의 평형상수는 압력 및 온도 증가와 더불어 증가 또는 감소하고 흡수계수는 대체로 증가함을 알았다. 이들 각 평형상수로부터 착물형성에 따른 부피, 엔탈피, 자유에너지 및 엔트로피 변화량을 구하였다. 도한 압력 증가에 의한 red-shift, 온도 증가에 의한 blue-shift 현상 및 압력 변화에 의한 진동자세기의 관계를 열역학함수와 관계지어 설명하였다.