• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.499-504
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• 2012

The specific rates of sovolysis of 4-methylthiophene-2-carbonyl chloride (1) have been determined in 26 pure and binary solvents at $25.0^{\circ}C$. Product selectivities are reported for solvolyses of 1 in aqueous ethanol and methanol binary mixtures. Comparison of the specific rates of solvolyses of 1 with those for p-methoxybenzoyl chloride (2) in terms of linear free energy relationships (LFER) are helpful in mechanistic considerations, as is also treatment in terms of the extended Grunwald-Winstein equation. It is proposed that the solvolyses of 1 in binary aqueous solvent mixtures proceed through an SN1 and/or ionization (I) pathway rather than through an associative $S_N2$ and/or addition-elimination (A-E) pathway.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1793-1796
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• 2010

• Journal of Power Electronics
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• v.16 no.2
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• pp.717-730
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• 2016

The harmonic components of grid voltage result in oscillations of the calculated phase obtained via phase synchronization. This affects the security and stability of grid-connected converters. Moving average filter, delayed signal cancellation and their related harmonic elimination algorithms are major methods for such issues. However, all of the existing methods have their limitations in dealing with multiple harmonics issues. Furthermore, few studies have focused on a comparison and evaluation of these algorithms to achieve optimal algorithm selections in specific applications. In this paper, these algorithms are quantitatively analyzed based on the derived mathematical models. Moreover, an enhanced moving average filter and enhanced delayed signal cancellation algorithms, which are applicable for eliminating a group of selective harmonics with only one calculation block, are proposed. On this basis, both a comprehensive comparison and a quantitative evaluation of all of the aforementioned algorithms are made from several aspects, including response speed, required data storage size, sensitivity to sampling frequency, and elimination of random noise and harmonics. With the conclusions derived in this paper, better overall performance in terms of harmonic elimination can be achieved. In addition, experimental results under different conditions demonstrate the validity of this study.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2413-2417
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• 2011

The specific rates of solvolysis of 1- naphthyl chloroformate (1-NaphOCOCl, 1) and 2-naphthyl chloroformate (2-NaphOCOCl, 2) have been determined in a wide range of solvents at 2.0 and 10.0$^{\circ}C$. These give a satisfactory correlation over the full range of solvents when the extended (two-term) Grunwald-Winstein equation is applied. The sensitivities (l and m-values) to changes in solvent nucleophilicity ($N_T$) and solvent ionizing power ($Y_{Cl}$) are similar to those reported previously for solvolysis of phenyl chloroformate, which has been suggested to proceed through an addition-elimination mechanism with the addition step being rate determining. For four representative solvents, studies were made at several temperatures and activation parameters determined. These observations were also compared with those previously reported for phenyl chloroformates and naphthoyl chlorides.

• Journal of the Korean Society of Costume
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• v.62 no.7
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• pp.97-116
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• 2012

The purpose of this study is to analyze the trench coat designs shown in the latest collection by using a checklist method among many fashion design idea methods and then investigate the trend of trench coat design in multilateral directions. As for the research method, 1,307 photos selected from the photos of women's trench coats publicized from 2006 until 2011 were used for the analysis and then a frequency analysis was conducted. As a result, the types of checklist methods shown in trench coats included modification type, elimination type, conversion type, combination type, minimization type, addition type, and magnification type. In the modification type, the modification of color to the back side stood out; in the elimination type, the design eliminating epaulet stood out ; in the conversion type, conversion to jacket among many items stood out. In the combination type, the combination between different material texture and identical colors among colors stood out ; in the minimization type, the design minimizing sleeves stood out; in the addition type, the addition of sleeves among many details stood out ; in the magnification type, the design magnifying panels stood out.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.657-661
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• 2007

The specific rates of solvolysis of isopropyl fluoroformate are well correlated using the extended Grunwald-Winstein equation, with a sensitivity (l ) to changes in solvent nucleophilicity (NT) and a sensitivity (m) to changes in solvent ionizing power (YCl). The sensitivities (l = 1.59 ± 0.16 and m = 0.80 ± 0.06) toward changes in solvent nucleophilicity and solvent ionizing power, and the kF/kCl values are very similar to those for solvolyses of n-octyl fluoroformate, suggesting that the addition step of an addition-elimination mechanism is rate-determining. For methanolysis, a solvent deuterium isotope effect of 2.53 is compatible with the incorporation of general-base catalysis into the substitution process. The large negative values for the entropies of activation are consistent with the bimolecular nature of the proposed rate-determining step. These observations are also compared with those previously reported for the corresponding chloroformate and fluoroformate esters.

• Journal of Fisheries and Marine Sciences Education
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• v.7 no.1
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• pp.111-126
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• 1995

In general, the electromagnetic transient phenomenon always exists in induction motor(IM) with the torque change. The control performance of IM is very worse than that of D.C motor owing to this transient phenomenon. So many studies about the elimination methods of the transient phenomenon have been making progress. Interesting methods of them are the Field acceleration method(FAM) and the method of impulse addition on the input voltage at the time point of torque change. In this paper, first, the circuit equation of IM is derived from the phase segregation method. The torque equation consisted of the stator and rotor currents is derived from the solving of the circuit equation. As we well known, the transient terms exist in this the torque equation. The method of impulse addition on the input voltage at the instance of torque change is confirmed theoretically for the elimination of the transient phenomenon. With the base on it, the author proposed a real time algorithm to eliminate the transient terms. The control system is consisted of the PI controller with the feedforward of torque change. The author could confirm that the quick stepwise responses of torque and speed can be obtained from response simulations.

• Korean Journal of Adult Nursing
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• v.15 no.2
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• pp.267-277
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• 2003

Purpose: The purpose of this study was to evaluate the applicability of braden scale to assess pressure ulcer risk patients and to identify additional risk factors of pressure sores in an neurologic intensive care unit. Method: The subjects of this study were 66 patients in neurologic intensive care units. Data was prospectively collected from Sep. to Dec., 2002. Data were analyzed by mean, percentage, t-test, chi-square, discriminant analysis using Spss pc+. Result: The results of this study were as follows: 1) There was a significant difference between scoring of braden scale and pressure ulcer development. The subscales that predicted pressure ulcer development using braden scale only were sensory perception, moisture, mobility, friction & shear. By using these subscales, sensitivity was 86.7%, and specificity was 61.1%, and total hit ratio was 72.7%. 2) Additional pressure ulcer risk factors which showed significance for discriminating two group were protein, albumin, gender, level of consciousness, pattern of bowel elimination. By using the combination of these additional risk factors in addition to the braden scale, total hit ratio increased to 84.8%. Conclusion: This data suggest that albumin, protein, gender, level of consciousness, pattern of bowel elimination in addition to the braden scale should be included in the pressure sore assessment tool.

• Journal of the Korean Applied Science and Technology
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• v.22 no.2
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• pp.106-115
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• 2005

Bio-diesel as fatty acid methyl ester was derived from such oils as soybean, peanut and canola oil by lipase catalyzed continuous trans-esterification. So the activation of lipase(Novozym - 435) was kept to be up to 4:1, the limiting molar ratio of methanol to oil under one-step addition of methanol due to the miscibility of oil and methanol through the static mixer for 4hrs and the elimination of glycerol on the surface of lipase by 7wt% silica gel. Therefore the overall yield of fatty acid methyl ester from soybean oil appeared to be 98% at 50$^{\cdot}C$ of reaction temperature under two-steps addition of methanol with 2${\times}$2:1 of methanol to oil molar ratio at an interval of 5.5hrs, 7wt% of lipase, 24 number of mixer elements, 0.2ml/min of flow rate and 7wt% of silica gel.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3657-3664
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• 2012

Reactions of 1-adamantylmethyl chloroformate ($1-AdCH_2OCOCl$, 1) and 1-adamantylmethyl fluoroformate ($1-AdCH_2OCOF$, 2) in hydroxylic solvents have been studied. Application of the extended Grunwald-Winstein (G-W) equation to solvolyses of 1 in a variety of pure and binary solvents indicates an addition-elimination pathway in the majority of the solvents except an ionization pathway in the solvents of relatively low nucleophilcity and high ionizing power. The solvolyses of 2 show an addition-elimination pathway in all of the mixed solvents. The leaving group effects ($k_F/k_{Cl}$), the kinetic solvent isotope effects (KSIEs, $k_{MeOH}/k_{MeOD}$), and the enthalpy and entropy of activation for the solvolyses of 1 and 2 were also calculated. The selectivity values (S) for each solvent composition are reported and discussed. These observations are compared with those previously reported for other alkyl haloformate esters.