• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.407-416
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• 2019

The criticical micelle concentration (CMC) was measured by using the UV-Vis method for the micellization of the ammonium type cationic surfactants (DTAB, TTAB, and CTAB) in the aqueous aniline solution. The enthalpy change (${\Delta}H^0$) and entropy change (${\Delta}S^0$) were calculated from the dependence of Gibbs free energy change (${\Delta}G^0$) on the temperature for micellization of the cationic surfactants between 290K and 314K. The effects of n-butanol and sodium chloride on the micellization of cationic surfactants were measured and compared with the other thermodynamic functions. All the free energy changes (${\Delta}G^0$) of the micellization were negative, all the enthalpy change (${\Delta}H^0$) were negative, and all the entropy change (${\Delta}S^0$) were positive values, respectively. The micelle formation of cationic surfactant in aniline solution is a spontaneous exothermic reaction, and the iso-structural temperature calculated from the thermodynamic values show that enthalpy and entropy contribution to the micellization are almost the same for the micellization of cationic surfactants

• Economic and Environmental Geology
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• v.32 no.3
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• pp.237-245
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• 1999

The Mujeong au-Ag hydrothermal vein type deposits occur within the Teriary igneous rocks of the Janggi basin. Ore minerals consist of pyrite, pyrrhotite, sphalertite, chalcopyrite, galena, cosalite, lillianite, argentite and electrum, and associated with epidotization, sericitization and pyritization. Fluid inclusion studies reveal that ore fluids were low saline with a simple NaCl-$H_{2}O$ system. Fluid inclusion data indicate that homogenization temperatures and salinities of fluid are 150 to $340^{\circ}C$ and 1.0 to 6.5wt.% NaCl equivalent, respectively. Sulfur isotope compositions of sulfied minerals ( ${\delta}^{34}S$=6.2 to 9.6$\textperthousand$) indicate that the ${\delta}^{34}S_{H2S}$ value of ore fluids was about 10.4$\textperthousand$. This ${\delta}^{34}S_{H2S}$ value is likely consistent with and hydrothermal sulfur, whereas the fluids were highly influenced by mixing with meteoric water. Measured and calculated oxygen and hydrogen isotope values (${\delta}^{18}O_{H2O}$=-2.7 to 3.4 $\textperthousand$, ${\delta}D_{H2O}$ = -83.6 to -52.7 $\textperthousand$) of ore forming fluids suggest mixing with hydrothermal and meteoric water. Equilibrium thermodynamic interpretation by mineral assemblages and chemistry indicates that sulfur fugacities (-log $fs_2$) ore forming fluids range from 9.0 to 12.6 atm stage II.

• Coupled systems mechanics
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• v.5 no.4
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• pp.285-304
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• 2016

The effects of large rotations and p-delta on the dynamic response of a structure subjected to seismic loading and local uplift of its foundation were analyzed in this work. The structure was modeled by an equivalent flexible mat mounted on a rigid foundation that is supported either by a Winkler soil type or a rigid soil. The equations of motion of the system were derived by taking into account the equilibrium of the coupled foundation-mat system where the structure was idealized as a single-degree-of-freedom. The obtained nonlinear coupled system of ordinary differential equations was integrated by using an adequate numerical scheme. A parametric study was performed then in order to evaluate the maximum response of the system as function of the intensity of the earthquake, the slenderness of the structure, the ratio of the mass of the foundation to the mass of the structure. Three cases were considered: (i) local uplift of foundation under large rotation with the p-delta effect, (ii) local uplift of foundation under large rotation without including the p-delta effect, (iii) local uplift of foundation under small rotation. It was found that, in the considered ranges of parameters and for moderate earthquakes, assuming small rotation of foundation under seismic loading can yield more adverse structural response, while the p-delta effect has almost no effect.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.129-135
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• 1997

Previous studies has shown that the curve of low-cycle fatigue life was not expressed with the single line subjected to Manson-Coffin's law type and bent to short life in low ${\Delta}{\varepsilon}_p$ region. The main cause of this phenomenon has been considered that the localization of plastic strain in the crack initiation process fosters the crack initiation. In this study, the low-cycle fatigue life was investigated for each specimens omitted crack initiation process and it was found that fatigue life curve in log(${\Delta}{\varepsilon}_p$)-log($N_f$)was bent in low ${\Delta}{\varepsilon}_p$ region as ever. Therefore, the main cause of appearance of knee point in fatigue life curve is not found in the crack initiation process but in the crack propagation process. In the crack propagation process, the localization of the plastic strain in the vicinity of crack tip and the influence of test environment on the crack propagation rate were observed and these inclinations were more remarkable in low ${\Delta}{\varepsilon}_p$ region. Hence, it was concluded that these two phenomena in the crack propagation process were proved to the main cause which accelerates the crack propagation in low ${\Delta}{\varepsilon}_p$ region and bent the fatigue life curve in result.

• Journal of Microbiology and Biotechnology
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• v.24 no.3
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• pp.401-407
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• 2014

Quorum sensing and the stringent response are well-known regulation systems for the expression of virulence genes in enterohemorrhagic Escherichia coli (EHEC). However, how these two systems interact is not well known. E. coli strains with mutations in two regulation systems, ${\Delta}luxS$ (ECM101) and ${\Delta}luxS{\Delta}relA{\Delta}spoT$ (ECM201), and the ${\Delta}luxS$ complement strain to ECM201 (ECM202) were created from EHEC O157:H7 EDL933 to investigate how the regulatory systems interact. The phenotypic changes of the mutant strains were characterized and compared with the wild type. The mutant strains exhibited no obvious growth defects, although acid resistance and cellular cytotoxicity were decreased significantly in all the mutant strains. Phenotypic characterization revealed that mutations in the stringent response system (ECM201 and ECM202) influenced the metabolic (defective utilization of arabinose and L-sorbose) and enzymatic activities (decreased trypsin activity, and increased ${\alpha}$-glucosidase activity). In contrast, the quorum sensing system mutant (ECM101) did not display these phenotypes. The motility of the quorum sensing system mutant (ECM101) was unchanged, but mutation in the stringent response system influenced the motility. Our results suggest that quorum sensing interacts with the stringent response regulation system.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.175-182
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• 2021

The purpose of this study is to propose policy implications for improving the efficiency of corporate income tax management in Vietnam, by analyzing the study factors affecting the efficiency of corporate income tax management (evidence from Mekong Delta provinces, Vietnam). This study used a primary data collection method and collected data of 329 enterprises, including 49 joint-stock companies and 280 limited liability companies in 3 provinces - Tra Vinh province, Soc Trang province, and Ben Tre province. By using the binary regression method, the author discovered eight factors affecting the efficiency of corporate income tax management in the Mekong Delta region such as the time of operation of the enterprises, type of business, gender, business results, tax amount temporarily paid, compliance with tax policies, business scale, and tax debt ratio. From the above research results, the author proposes policies to support Tax Departments to improve the efficiency of corporate income tax management in the Mekong Delta region in the future. These policies include - for further promoting the tax policy propaganda to enterprises, tax authorities need to promptly handle tax arrears, enhance the inspection of tax debt enterprises, and focus on the business models, gender, age of the business owners, etc.

• The Pure and Applied Mathematics
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• v.19 no.2
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• pp.87-102
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• 2012

In this paper, we consider the Fourier-type functionals introduced in [16]. We then establish the analytic Feynman integral for the Fourier-type functionals. Further, we get a series expansion of the analytic Feynman integral for the Fourier-type functional $[{\Delta}^kF]^{\^}$. We conclude by applying our series expansion to several interesting functionals.

• Economic and Environmental Geology
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• v.26 no.3
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• pp.267-278
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• 1993

Serpentinite rocks which are composed mainly of olivine, serpentine and clinopyroxene, cropped out in the anorogenic Kyongsang sedimentary basin of South Korea. The serpentinites contain high content of MgO (36.87~41.99%) and 47~67 ppm Co, 1185~2042 ppm Ni and 979~3582 ppm Cr, which are quite similar to those of ultrabasic rocks such as peridotite and dunite. Isotopic compositions of serpentinites range from -95.5 to -105.7‰ in ${\delta}D$ and +1.7 to 7.1‰ in ${\delta}^{18}O$ corresponding to the continental antigorite type. A wide variation of oxygen isotopic values and $H_2O^+$ content of serpentinites reflect the different water/rock ratios during serpentinization processes. Formation temperature of serpentine minerals are estimated to be unusually high temperature of $488{\sim}646^{\circ}C$ by serpentine-magnetite isotopic fractionation, which belong to continental antigorite type. Calculated ${\delta}^{18}O$ value of serpentinized fluid during serpentinization is suggested that the hydrothermal fluid responsible for serpentinization be originated from the magmatic fluid with a minor influx of paleo-meteoric water in this area.

• Smart Structures and Systems
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• v.3 no.2
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• pp.133-146
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• 2007

This paper addresses a new type of broad and stage-based hybrid carbon fiber reinforced polymer (HCFRP) sensor that is suitable for the sensing of infrastructures. The HCFRP sensors, a type of composite sensor, are fabricated with three types of carbon tows of different strength and moduli. For all of the specimens, the active materials are carbon tows by virtue of their electrical conductivity and piezoresistivity. The measurement principles are based on the micro- and macro-fractures of different types of carbon tows. A series of experiments are carried out to investigate the sensing performances of the HCFRP sensors. The main variables include the stack order and volume fractions of different types of carbon tows. It is shown that the change in electrical resistance is in direct proportion to the strain/load in low strain ranges. However, the fractional change in electrical resistance (${\Delta}R/R_0$) is smaller than 2% prior to the macrofractures of carbon tows. In order to improve the resistance changes, measures are taken that can enhance the values of ${\Delta}R/R_0$ by more than 2 times during low strain ranges. In high strain ranges, the electrical resistance changes markedly with strain/load in a step-wise manner due to the gradual ruptures of different types of carbon tows at different strain amplitudes. The values of ${\Delta}R/R_0$ due to the fracture of high modulus carbon tows are larger than 36%. Thus, it is demonstrated that the HCFRP sensors have a broad and stage-based sensing capability.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.1 s.307
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• pp.39-44
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• 2006

Pattern noise in the Delta-Sigma modulator is a well Known phenomenon that intrigued many circuit designers. These noise appear as the modulator output falls into a cyclic mode of operation. This paper addresses the dependence of these tone signal upon the system topologies. Among the four well known single-stage DSM topologies, namely Cascade of Integrators with Feedback Form(CIFB), Cascade of Integrators with Feedforward Form(CIFF), Cascade of Resonators with Feedback Form(CRFB), and Cascade of Resonators with Feedforward Form(CRFF), resonator type DSMs turn out to be more susceptible to the pattern noise than the integrator type. Noise transfer functions of the investigated topologies are also presented.