• Korean Journal of Acupuncture
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• v.27 no.1
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• pp.87-106
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• 2010

Objective & Methods: The purpose of this study is to investigate the anti-oxidative and immuneregulative effects of electro-acupouncture(EA) at SP6(Sameumgyo) in aged rats. The author performed several experimental items including blood cell counts, blood chemistry, measurement of various oxidants and antioxidants in liver and spleen, analysis of various cytokines in spleen. The results are as follows. Results: 1. EA at SP6 significantly reduced the number of platelets in blood. 2. EA at SP6 significantly reduced NO concentration and significantly increased catalase activity in liver. 3. EA at SP6 significantly reduced NO concentration and significantly increased SOD activity, catalase activity and glutathione concentration in spleen. 4. EA at SP6 restored the increase of IL-4, IL-6 and the decrease of IFN-$\gamma$ in aged rat spleen. Conclusion: According to these results, it is postulated that EA at SP6 has an antioxidative effect through increasing the activities of antioxidative enzymes and inhibiting production of oxidized substances, as well as an immune regulative effect in aging process. In consequence, it is presumed that EA at SP6 may have an anti-aging effect.

• Analytical Science and Technology
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• v.19 no.6
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• pp.519-528
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• 2006

An analytical method for the determination of thyroid hormones in urine samples has been studied by using solid-phase extraction and high-performance liquid chromatography/diode array detector/electro-spray mass spectrometry. Seven thyroid hormones were successfully separated by gradient elution on the reverse phase Hypersil ODS column (4.6 mm I.D., 100 mm length, particle size $5{\mu}m$) with ammonium formate buffer and acetonitrile, and UV spectra and mass fragment could be confirmed. The extraction recoveries of thyroid hormones in the urine samples (pH 3) were in the range of 89.0-113.1% with solid-phase extraction by C18, followed by elution with 4 ml of methanol/ammonium hydroxide (9 : 1). The calibration curves showed good linearity with the correlation coefficients ($r^2$) varying from 0.992 to 0.998 and the detection limits of all analytes were obtained in the range of 2-4 ng/ml (3.8-13.0 pmol/ml).

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.527-532
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• 2005

Ionic polymer metal composites (IPMC) are soft polymeric smart materials having large displacement at low voltage in air and water. The polymeric electrolyte actuator consists of a thin and porous membrane and metal electrodes plated on both faces, in impregnation electro-plating method. The response and actuation of actuator are governed. Among many factors governing the activation and response of IPMC actuator, the surface electrode plays an important role. In this study, the well-designed modification of electrode surface was carried out in order to improve the chemical stability well as electromechanical characteristics of the IPMC actuator. We employed Ion Beam Assisted Deposition (IBAD) method to prepare the topologically homogeneous thin surface electrode. After roughing the surface of Nafion membrane in order to get a larger surface area, the IPMC was prepared by impregnation for electro-plating and re- coating on the surface through traditional chemical deposition, followed by an additional surface treatment with high conductive metals with IBAD. It was observed that our IPMC specimen shows the enhanced surface electrical properties as well as the improved actuation and response characteristics under applied electric field.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.579-584
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• 1998

Polymer dispersed liquid crystal(PDLC) composite films were made by polymerization induced phase separation method using UV-curing to investigate the effect of fabrication conditions, such as photoinitiator concentration, film thickness, polymerization temperature, and electric field during polymerization, etc., on the electro-optic properties. As the amount of photoinitiator increased, the driving voltage of PDLC device increased due to the increase of small-size liquid crystal phases. This was considered as the results from the increased interfacial area between liquid crystal (LC) and polymer matrix, since LC molecules at the interfacial regions were relatively difficult to response for the applied electric field. When the higher molecular weight oligomer (PTDA-1000) was used as matrix, the initial transmittance was observed to be relatively higher than that for the lower molecular weight oligomer (PTDA-250). Saturation transmittance for PTDA-1000 was observed at relatively lower voltage than that for PTDA-250, of which transmittance was not saturated even at 60 V. As polymerization temperature increased, the initial transmittance of resulting PDLC film increased due to the larger LC droplets formation and the more matched refractive index between LC and matrix than those cases for the lower polymerization temperature. Though driving voltage decreased for the thinner film, it was considered that optimum thickness of the film should be maintained to get some practical contrast, which is the ratio of off- and on-state transmittance. Furthermore, electro-optic properties such as initial transmittance, driving voltage, and response time were observed to be considerably affected by application of external field during polymerization.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.593-598
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• 2013

In this study, we have evaluated the water absorption phenomenon of photoresist dry film, which is commonly used to build circuits on PCB (Printed Circuit Board) by photolithography, by using ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared). We have firstly observed significant change in fracture mode of dry film with respect to temperature and humidity, which we assumed the material transition from ductile to brittle. Secondly, we have established the process of absorption test for determining the diffusion coefficients of water into the dry film both with gravimeter and ATR-FTIR. We have successfully calculated the diffusion coefficients for each environmental conditions from the results which we achieved by gravimeter and ATR-FTIR. Compared to the gravimeter which is a conventional method for absorption test, the ATR-FTIR method in this study has been found to be very easy to use and have the same accuracy as gravimeter. Moreover, we are expecting to use the ATR-FTIR as an appropriate method to study the absorption phenomena related to any kinds of solvent and polymer system.

• Journal of Electrochemical Science and Technology
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• v.10 no.4
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• pp.416-423
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• 2019

A novel non-enzymatic oxalic acid (OA) sensor based on the platinum/carbon black-nickel-reduced graphene oxide (Pt/CBNi-rGO) nanocomposite is reported. The nanocomposites were prepared by the ethylene glycol reduction method. Their morphology and chemical composition were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The results clearly demonstrated the formation of the Pt/CB-Ni-rGO nanocomposite. The electrocatalytic activity of the Pt/CB-Ni-rGO electrode was investigated by cyclic voltammetry. It was determined that the appropriate amount of Pt enhanced the catalytic activity of Pt for oxalic acid electro-oxidation. Moreover, the modified electrode was determined to be highly selective for oxalic acid without interference from compounds commonly found in urine including uric acid and ascorbic acid. The chronoamperometric signal gave a wide linearity range of 20 μM-60 mM and the detection limit (3σ) was found to be 2.35 μM. The proposed method showed high selectivity, stability, and good reproducibility and could be used with micro-volumes of sample for the detection of oxalic acid. Finally, the oxalic acid content in artificial and control urine samples were successfully determined by our proposed electrode.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.402-406
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• 2013

In this study, a pitch for melt-electrospinning was prepared from naphtha cracking bottom (NCB) oil by the modification with heat treatment. The softening point and property of the modified pitch was influenced by modification conditions such as nitrogen flow rate, heat treatment temperature, and reaction time. Among these, the heat treatment temperature had a very strong influence on the distribution of molecular weight and softening point of the pitch. The C/H mole ratio and average molecular weight increased with increasing the heat treatment temperature due the decomposition and cyclization reaction of surface-functional groups. In addition, the values of benzene insoluble and quinoline insoluble also tends to decrease, and the width of molecular weight distribution seems to get more narrow. The carbon fiber with a diameter of $4.8{\mu}m$ was prepared from a modified pitch at the softening point of $155^{\circ}C$ by melt-electrospinning. It is believed that the melt-electro spinning method is much more convenient to get the thinner fiber than the conventional melt spinning method.

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.83-91
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• 1993

The eletrochemical behavior of light lanthanide complexes has been investigated by several electrochemical techniques in alkaline solutions. The composition of the complexes was determined by spectrophotometric method to be 1 : 1 and reduction mechanism was two steps 1 electron transfer reaction. The half wave potential of first peak depended on pH and cathodic current showed remarkably adsorptive properties. The results of DC and CV investigation demonstrated the quise-reversible nature of the electron transfer. The anion radical formed after first one electron reduction process, dimerizes to form dimer. The apparent irreversible behavior of the second wave is a result of the existence of a fast protonation following the second electron transfer. An exhaustive electrolysis was carried out at controlled potential of -1.80 V, deep blue color of the solution became progressively weaker, and then the solution became colorless solution. The final product of an exhaustive electrolysis is electro-inactive. The appearance of four steps may be explained by the fact the reduction of Ln-OCP elucidated ECEC mechanism.

• Journal of Environmental Science International
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• v.30 no.2
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• pp.161-172
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• 2021

This study was initiated to isolate the microorganisms removing phosphorus (P) from domestic sewage and to investigate the effects of environmental factors on the growth and P removal of the isolated bacteria. Microorganisms isolated from the sewage were identified as Chryseobacterium sp., Stenotrophomonas maltophilia, and Bacillus licheniformis. Among them, Bacillus licheniformis was selected as the P removal microorganism. The environmental factors considered in this study included initial phosphorus concentration, temperature, pH, and carbon source. At initial P concentrations of 10, 20, and 30 mg/L, the P removal efficiencies were 100.0%, 84.0%, and 16.5%, respectively. At 20℃, 30℃, and 40℃, the P removal efficiencies were 0%, 75.8%, and 60.6%, respectively. The removal efficiencies of phosphorus according to pH were 1.6%, 91.7%, and 51.1% at pH 5, pH 7, and pH 9, respectively. Using glucose, acetate, and glucose + acetate as carbon sources yielded P removal efficiencies of 80.9%, 33.6%, and 54.1%, respectively. Therefore, the results from the study demonstrated that the P removal efficiencies of Bacillus licheniformis were the highest when the initial P concentration, temperature, pH, and carbon source were 10 mg/L, 30℃, 7, and glucose, respectively.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.649-659
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• 2023

This study was initiated to evaluate the phosphorus (P) removal and diesel oil degradation by bacteria isolated from industrial wastewater. The bacteria isolated were identified as Bacillus sp. The P removal efficiencies by Bacillus sp. were 99% at the initial 20 mg/L P concentration. The diesel degradation efficiencies by Bacillus sp. were 86.4% at an initial 1% diesel concentration. Lipophilicity by bacteria was the highest in the log phase, whereas it was the lowest in the death phase. As the diesel was used as a carbon source, P removal efficiencies by Bacillus sp. were 68%. When glucose, acetate, and a mixture of glucose and acetate as second carbon sources were added, the diesel degradation efficiencies were 69.22%, 65.46%, and 51.46%, respectively. The diesel degradation efficiency was higher in the individual additions of glucose or acetate than in the mixture of glucose and acetate. When P concentration increased from 20 mg/L to 30 mg/L, the diesel degradation efficiency was increased by 7% from 65% to 72%, whereas when P concentration was increased from 30 mg/L to 40 mg/L, there was no increase in diesel degradation. One of the five proteins identified by proteome analysis in the 0.5% diesel-treated samples may be involved in alkane degradation and is known as the cytochrome P450 system. Also, two of the sixteen proteins identified in the 1.5% diesel-treated samples may be implicated in the fatty acid transport system and alcohol dehydrogenation.