• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.555-561
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• 2001

Vinyl acetate usually used in PVA resin preparation was converted to PVAc by bulk polymerization using AIBN as a initiator and PVA was synthesized by changing the concentration of NaOH added for saponification subsequently. As a result of estimating molecular weight using GPC, molecular weight increased as the NaOH concentration increased to 2.5 N, 5.0 N, 7.5 N and 10.0 N and polydispersity had similar values of 2.1~2.3, however, showed slightly decreasing tendency. In addition, PVA saponificated by 10.0 N-NaOH showed high syndiotacticity in observation of tacticity using NMR spectroscopy. From this fact, the degree of tacticity was predicted to be high and it was in good agreement with the tendency of polydispersity by GPC. Also, from the result of FT-IR spectroscopy, it might be known that hydrolysis was more promoted in the PVA with 10.0 N-NaOH than other NaOH concentration. Intrinsic viscosity measured using Ubbelohde viscometer, which increased as the concentration of NaOH added for saponification increased. The change of shear strength with the change of shear rate was investigated using Brookfield viscometer, in consequence, viscosity of PVA synthesized decreased as shear rate increased. PVA solution confirmed to show the shear thining behavior by Casson plot and PVA with 10.0 N-NaOH had the largest yield value. DSC measurement was performed to know the thermal properties of PVA. Tp had nearly constant value of 214$^{\circ}C$ in all cases except for adding 2.5 N-NaOH and $\Delta$H was increased as the concentration of NaOH increased. From this properties, it was concluded that the degree of hydrogen bonding was proportional to the added concentration of NaOH and the increase of the degree of hydrogen bonding and hydrophobic interaction could affect the rheological and thermal properties of title compound.

• Journal of the Korean Society of Clothing and Textiles
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• v.16 no.3 s.43
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• pp.335-344
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• 1992

This study was conducted to investigate the influence of addition of cetyl trimethyl ammo­nium bromide (CTAB), and amine [ethylamine (EA) or ethylene diamine (EDA)] to aqueous sodium hydroxide (NaOH) solution on polyester alkaline hydrolysis, The experimental vari­ables such as CTAB concentration, EA or EDA concentration, NaOH concentration, tempera­ture and time were compared, and the changes in physical and chemical properties of alkaline­hydrolyzed PET fabrics depending on their treated conditions were measured, The results are as follows: 1. By adding CTAB and amine in aqueous NaOH solution, increasing effect on weight loss of PET fabrics was obtained in simultaneous addition of CTAB and EDA, but not in CTAB and EA. 2. By adding CTAB & EDA simultaneously, increasing effect on weight loss was obtained regardless of EDA concentration, time and temperature, and it was more effective at lower NaOH concentration. :l. The increase of void space (or irregularly grooved surface), of softness, of wickability, of dyeability on PET fabric, and the decrease of tensile strength, of molecular weight were observed according to the weight loss on the PET fabrics. These changes were equal to all alkaline-hydrolyzed PET fabrics regardless of addition of CTAB and amine. l. There was little changes on crystallinity, thermal behavior when PET fiber was treated with ,aqueous NaOH solution with CTAB and EDA. These results supported that increasing effect on weight loss take place without inducing of fine structural change of PET fibers.

• Journal of environmental and Sanitary engineering
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• v.10 no.3
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• pp.99-104
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• 1995

The objective of this study was to investigate the effect on denuclearization and decertification of flue gas by utilizing Mg( OH)$_{2}$ and NaOH as reagents in industrial boiler. We used packed absorber with Tellerette in all cases. And pH of circulation solution, rate of liquid per gas in absorber, COD concentration by pH variation in oxidation basin were inves- tigated. The following conclusions were obtained from experimental results: 1. Concerning running cost for reagents, Mg( OH)$_{2}$ reagent for treatment of flue gas was more economical than NaOH. 2. While Mg( OH )$_{2}$ and NaOH as absorbents were used, then the ratio of denuclearization was 96 and 97% respectively and nitrification was recorded 29 and 25% . 3. In this absorption tests the optimum condition for ratio of liquid per gas, pH and nonregenerable salt concentration of circulation solution were 3.6ℓ /Nm$^{3}$, 6.0, 0.5∼1.0% respectively, 4. Initial COD in oxidation basin was 800 ∼ 1,00099ut after adjusting to pH 7.0, COD of effluent water was less than 20ppm.

• Korean Journal of Pharmacognosy
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• v.41 no.4
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• pp.250-254
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• 2010

This study was presented to the physiological activities such as metal chelating capacity, superoxide dismutase-like activity, anti-inflammation, cytotoxicity from Zanthoxylum schnifolium fruit. The values for metal chelating capacity of 1 mg/mL of 70% EtOH and 70% MeOH extracts were 68% and 67%, respectively, it was shown that metal chelating capacity in a dose-dependent manner. The 100% EtOH and 100% MeOH extract exhibited strong superoxide dismutase-like activity. The highest SOD-like activity obtained from 100% EtOH was 51% at a concentration of 4 mg/mL. The all extracts of Zanthoxylum schnifolium fruit except $H_2O$ extract significantly decreased the concentration of LPS-induced NO in Raw 264.7 cells. The 100% EtOH, 100% MeOH and 70% EtOH extract represented the highest activity in the anti-inflammation properties in vitro. However, the 100% EtOH and 100% MeOH extracts has cytotoxicity in Raw 264.7 cells and it may affect cell viability. Conclude that 70% EtOH extract was most suitable for anti-inflammation. Our results revealed that the Zanthoxylum schnifolium fruit expected to physiological activities.

• Applied Chemistry for Engineering
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• v.34 no.2
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• pp.175-179
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• 2023

Herein we present a tested aqueous based redox flow battery (RFB) that employs phosphomolybdic acid and ferrocyanide as the negative and positive active species in an aqueous sodium hydroxide solution. The different concentrations of NaOH solution, such as 1.0, 1.2, 1.4, 1.5, and 1.6 M, were prepared for checking the electrochemical properties and stability. The NaOH concentration as a supporting electrolyte in the negative species appears to play an important role in the electrochemical properties of phosphomolybdic acid. Moreover, the optimum value of the concentration is necessary for the best performance. The resistance of the electrolyte decreased with increasing the concentration up to 1.5 M and then increased to 1.6 M. Hence, the decrease in electrolyte resistance appears to greatly influence the energy efficiency, which is improved by increasing the concentration of NaOH. In addition, the 1.5 M NaOH solution appears to be the concentration required for optimum performance.

• The Research Journal of the Costume Culture
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• v.31 no.2
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• pp.248-261
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• 2023

The conditions for minimizing dyes and additives when dyeing cellulose fibers such as linen, ramie, and hemp fabrics were obtained using glucose, an organic reducing agent. Dyeability and colorfastness were measured through repeated dyeing. The overall surface dyeing concentration followed the linen>hemp>ramie order, and most of the colors were in the range of PB (PurpleBlue). As the glucose concentration increased, the blue series was strengthened, and the color was dark and clear. It was determined that glucose the concentration of 4g/L was appropriate for minimizing the amount of dye. When the dyeing temperature was 30℃, the surface dyeing concentration was the highest, and the color was dark and clear. Although the dyeing concentration increased as NaOH concentration increased, 3g/L (pH 12.37) was considered appropriate for the minimum NaOH concentration, which becomes gradual after the dyeing concentration increased rapidly. It was found that the surface dyeing concentration, when repeated six times for 5 min, was better than that of dyeing once for 30 min. Washing, rubbing, and perspiration colorfastness were all found to be excellent in grades 4-4-5, and colorfastness to light was excellent in grades 5 of linen and hemp and grade 4 of ramie.

• Journal of Korean Medical Science
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• v.33 no.53
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• pp.298.1-298.10
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• 2018

Background: The renal function of individuals is one of the reasons for the variations in therapeutic response to various drugs. Patients with renal impairment are often exposed to drug toxicity, even with drugs that are usually eliminated by hepatic metabolism. Previous study has reported an increased plasma concentration of indoxyl sulfate and decreased plasma concentration of $4{\beta}$-hydroxy (OH)-cholesterol in stable kidney transplant recipients, implicating indoxyl sulfate as a cytochrome P450 (CYP) inhibiting factor. In this study, we aimed to evaluate the impact of renal impairment severity-dependent accumulation of indoxyl sulfate on hepatic CYP3A activity using metabolic markers. Methods: Sixty-six subjects were enrolled in this study; based on estimated glomerular filtration rate (eGFR), they were classified as having mild, moderate, or severe renal impairment. The plasma concentration of indoxyl sulfate was quantified using liquid chromatography-mass spectrometry (LC-MS). Urinary and plasma markers ($6{\beta}$-OH-cortisol/cortisol, $6{\beta}$-OH-cortisone/cortisone, $4{\beta}$-OH-cholesterol) for hepatic CYP3A activity were quantified using gas chromatography-mass spectrometry (GC-MS). The total plasma concentration of cholesterol was measured using the enzymatic colorimetric assay to calculate the $4{\beta}$-OH-cholesterol/cholesterol ratio. The correlation between variables was assessed using Pearson's correlation test. Results: There was a significant negative correlation between MDRD eGFR and indoxyl sulfate levels. The levels of urinary $6{\beta}$-OH-cortisol/cortisol and $6{\beta}$-OH-cortisone/cortisone as well as plasma $4{\beta}$-OH-cholesterol and $4{\beta}$-OH-cholesterol/cholesterol were not correlated with MDRD eGFR and the plasma concentration of indoxyl sulfate. Conclusion: Hepatic CYP3A activity may not be affected by renal impairment-induced accumulation of plasma indoxyl sulfate.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.7-14
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• 2004

The lift-off characteristics of the triple flame have been studied experimentally with various mean velocities and concentration gradients using a multi-slot burner, which can control the concentration gradient and the mean velocity independently, Lift-off height, axial maximum velocity, flame temperature, and some other characteristics were examined for methane and propane flame, It was found that minimum values of the lift-off heights exist at a certain concentration gradient for constant mean velocity, and this result implies that the propagation velocity has a maximum value at this condition, OH radical distribution was measured with LIF method and velocity variation along streamline was measured with PlV system. In addition maximum temperature along streamline was measured with CARS system. The intensity of the diffusion flame affects on the propagation velocity of triple flame in the region of very weak concentration gradient.

• Communications for Statistical Applications and Methods
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• v.30 no.5
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• pp.517-530
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• 2023

Recent studies revealed that fine dust in ambient air may cause various health problems such as respiratory diseases and cancer. To prevent the toxic effects of fine dust, it is important to predict the concentration of fine dust in advance and to identify factors that are closely related to fine dust. In this study, we developed a Bayesian network model for predicting PM10 concentration in Seoul, Korea, and visualized the relationship between important factors. The network was trained by using air quality and meteorological data collected in Seoul between 2018 and 2021. The study results showed that current PM10 concentration, season, carbon monoxide (CO) were the top 3 effective factors in 24 hours ahead prediction of PM10 concentration in Seoul, and that there were interactive effects.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.6
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• pp.1-7
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• 2014

Dissolving part of xylan and lignin in lignocellulosic biomass by base can be used as pretreatment technique. Cork oak was pretreated with sodium hydroxide solution and the pretreatment effects were evaluated with two critical factors - NaOH concentration and pretreatment temperature. Some of xylan and lignin were removed by base pretreatment. At $90^{\circ}C$ and 13% NaOH pretreatment, 22.0% of lignin and 78.8% of xylan removed by base treatment. Enzymatic hydrolysis of cork oak which was pretreated at higher temperature or concentration was further improved. After pretreatment of cork oak with 13% NaOH at $90^{\circ}C$, the conversion rate of cellulose to fermentable sugars were reached up to 91.3%. At ethanol fermentation with enzymatic hydrolysate from different pretreatment conditions, all enzymatic saccharification liquids were well fermented by Saccharomyces cerevisiae.