• 한국의류학회지
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• 제24권7호
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• pp.1081-1087
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• 2000

Gromwell colorants were extracted with methanol and dried. Four fractions were obtained by silica gel adsorption column chromatography using step-wise elution method. Relative ratio of four fraction is 1.00:0.07:0.22:0.30(Fl:F2:F3:F4) and gromwell colorants mainly consist of Fl, F3 and F4. IR analysis shows that each fraction has similar structure. Main component of gromwell extracts is acetyl derivative of naphthoquinone, and the rest are isobutyl derivative and isovaleryl derivative etc., in order. Gromwell colorants exhibit relatively good affinity to protein and polyamide fibers, but low affinity to cellulose and regenerated cellulose fibers.

• 약학회지
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• 제17권4호
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• pp.223-234
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• 1973

Sixteen compounds of N-aroyl-N'-(4'-alkoxyphenyl) thiourea derivative, twenty one compounds of N-aeryl-N'(3'-hydroxy-4'-alkoxycar-bonylphenyl) thiourea derivative, three compounds of N-aeroyl-N'-.alpha.-naphthyiourea derivative and three compounds of N-cyanoacetyl-N'-aroyl thiosemicarbazide derivative were syntrhesized as potential antitubercular agent and were subjected to screening test for antitubercular activity against Mycobacterium turberculosis H/sub 37/Rv by tube dilution method in vitro. Of the fourty three eompounds, N-p-cyanobenzoyl-N'-(4'-iso-butoxyphenyl) thiourea, N-p-cyanobenzoyl-N'-(4-n-amoxyphenyl)thiourea, N-furoyl-N'-(3'-hydroxy-4'-ethoxycarbonylphenyl)thiourea, N-p-cyanobenzoyl-N'-(3'-hydroxy-4'-n-butoxycarbonylphenyl)thiourea, N-p-cyanobenzoyl-N'-(3'-hydroxy-4'-n-amoxycarbonylphenyl)thiourea, and N-5-nitrofuroyl-N'(3'-hydroxy-4"-n-amoxycarbonylphrnyl)thiourea showed the growth inhibition of M. tuberculosis H/sub 37/Rv at the coccentraction og 10.mu.g/ml, respectively.

• 약학회지
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• 제41권5호
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• pp.571-574
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• 1997

We have synthesized acetylsalicylic acid derivative of eugenol. And also, physico-chemical properties and analysis on this compound were examined. The correlation coefficient of the calibration curve in methanol solution was 0.9998. The hair growth stimulation of eugenol derivative on the hair of black mouse (C57BL/6), was also carried out using Implant method. When its ethanol solution was administered to the black mouse by route of skin, eugenol derivative promoted the growth of hair.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제5권4호
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• pp.310-315
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• 2005

This paper proposes a fast optimization method by combining queen-bee evolution and derivative evaluation in genetic algorithms. These two operations make it possible for genetic algorithms to focus on highly fitted individuals and rapidly evolved individuals, respectively. Even though the two operations can also increase the probability that genetic algorithms fall into premature convergence phenomenon, that can be controlled by strong mutation rates. That is, the two operations and the strong mutation strengthen exploitation and exploration of the genetic algorithms, respectively. As a result, the genetic algorithm employing queen-bee evolution and derivative evaluation finds optimum solutions more quickly than those employing one of them. This was proved by experiments with one pattern matching problem and two function optimization problems.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1764-1768
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• 2004

The present work reports on the investigations based on the interaction of sodium hydroxide with catechol derivatives. The first derivative spectra allowed the simultaneous determination of levodopa and carbidopa. The calibration graph was constructed from the first derivative signals by measuring $^1D$ at 350 nm for standard samples containing between 3 and 30 mg $L^{-1}$ of levodopa and at 305 nm for standard samples containing between 3 and 80 mg $L^{-1}$ of carbidopa. This method offers the advantages of simplicity, rapidity, selectivity and higher sensitivity than most of the existing spectophotometric methods.

• Tribology and Lubricants
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• 제17권4호
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• pp.283-289
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• 2001

The paper presents the stability characteristics of a rotor-bearing system supported by actively controlled hydrodynamic journal bearing. The proportional and derivative controls including coupled motion are adopted for the control algorithm to control the hydrodynamic journal bearing with a circumferentially groove. Also, the cavitation algorithm implementing the Jakobsson-Floberg-Olsson boundary condition is adopted to predict cavitation regions in the fluid film more accurately than a conventional analysis which uses the Reynolds condition. The stability characteristics of a rotor-bearing system supported by actively controlled hydrodynamic journal bearing are investigated for various control gains with the Routh-Hurwitz criteria using the linear dynamic coefficients which are obtained from the perturbation method. It is found that the speed at onset of the instability is increased for both proportional and derivative control of the bearing. It is also found that the proportional and derivative control of the coupled motion is more effective than that of the uncoupled motion.

• Journal of applied mathematics & informatics
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• 제28권1_2호
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• pp.109-130
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• 2010

In this paper, a numerical method for a weakly coupled system of two singularly perturbed convection-diffusion second order ordinary differential equations with the mixed type boundary conditions is presented. Parameter-uniform error bounds for the numerical solution and also to numerical derivative are established. Numerical results are provided to illustrate the theoretical results.

• 대한기계학회논문집A
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• 제24권3호
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• pp.543-549
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• 2000

Results of theoretical investigations of the stability characteristics of an actively controlled externally pressurized air journal bearing are presented. Proportional control and derivative control are used for the control algorithm of active air bearing. The stability characteristics of the actively controlled bearing operating at zero steady-state eccentricity is investigated with the step jump method. The speed at onset of instability is raised for both proportional control and derivative control of bearing. Proportional control increased the stability threshold without affecting the whirl ratio. But for derivative control of bearing, stability threshold increase is accompanied by a parallel reduction of the whirl ratio. Results show active control of bearing can be adopted for the stability improvement of air journal bearing.

• 대한기계학회논문집B
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• 제27권5호
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• pp.620-627
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• 2003

Radiative heat transfer in an axisymmetric enclosure with absorbing, emitting, and scattering medium is studied here by using the different methods such as MDOM, FVM, and FVM2 with emphasis on the treatment of angular derivative term, which appears in a curvilinear coordinates due to angular redistribution. After final discretization equation for FVM2 is introduced by using the step scheme and directional weights, present approach is validated by applying it to three different benchmarking problems with absorbing, emitting, and scattering medium.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2001년도 추계학술대회 논문집(Proceeding of the KOSME 2001 Autumn Annual Meeting)
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• pp.130-134
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• 2001

In the re-entry control system, errors apt to induce because the time derivative of drag acceleration is analytically estimated. Still more, the difficulty of estimation of the exact drag coefficient in hypersonic velocity and the nun-reality of the scale height cause a steady-state drag error. This paper proposes the additional method of the disturbance observer. This reduces the steady-state drag error according to the following series. First, this method estimates a error in drag acceleration time derivative by the analytic calculation and then creates the new drag acceleration time derivative using the estimated error. The performance of the re-entry control system is verified about 32 reference trajectories.