• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.737-744
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• 2021

An investigation is conducted to study a solid-liquid mixture vertically upward hydraulic transport of solid particles by non-Newtonian fluids in the Mud system. Rheology of particulate suspensions in viscoelastic fluids is of importance in many applications such as particle removal from surfaces, transport of proppants in fractured reservoir and cleaning of drilling holes, etc. In this study a clear acrylic pipe was used in order to observe the movement of solid particles. Annular velocities varied from 0.4 m/s to 1.2 m/s. The mud systems which were utilized included aqueous solution of sodium carboxymethyl cellulose (CMC) solutions. Main parameters considered in the study were inner-pipe rotary speed, fluid flow regime and particle injection rate. Solid volumetric concentration and pressure drops were measured for the various parameters such as inclination angle, flow rate, and rotational speed of inner cylinder.

• Advances in nano research
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• 제11권6호
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• pp.657-665
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• 2021

The present work aimed to explore green approach via aqueous leaves extract of Murraya koenigii (ALEMk) for the synthesis of silver nanoparticles (AgNPsMk) in single step. The synthesis process was visualized with a color change and monitored by employing UV/Visible spectroscopy and a clear peak attained at 420 nm confirming the synthesis of AgNPsMk. The possible functional groups present in the extract which participated in the synthesis of AgNPsMk were identified with the help of FTIR spectroscopy. Further characterization using TEM images revealed the spherical shape of AgNPsMk with average particle size of 20 nm displaying well dispersion throughout the solution. Pronounced antioxidant activities of AgNPsMk at increased concentrations observed which evidencing strong radical scavenging ability. Moreover, AgNPsMk exhibited strong antibacterial behavior when tested against bacterial strains of Escherichia coli and Bacillus subtilis. Moving ahead, in vitro cytotoxicity work revealed potent cell viability loss appearing in AU565 and HeLa cancer cell lines on exposure to AgNPsMk at increased concentration. Finally, in vivo assessment carried out inside male Wistar rats indicated non toxic effect on examined liver tissues besides biochemical analysis including bilirubin, alkaline phosphtase (ALP) and serum glutamate pyruvate transaminase (SGPT) which found within the normal range when compared with control. The prior research work profoundly apprises the potential of green synthesized AgNPsMk to play a significant role in biomedical applications and formulations.

• 대한융합한의학회지
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• 제4권1호
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• pp.29-36
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• 2022

Objectives : The purpose of this study was to investigate the anti-inflammatory effects of the aqueous extract of the steamed radix of Rehmanniae glutinosa (SRG) on periodontitis in ligature-induced rat model. Methods: To induce the periodontitis, ligature was placed around the lower first molar in rats. Rats were divided into 4 groups (n = 7), NL (non-ligatured and vehicle-treated), L (ligatured and vehicle-treated), SRG1 (ligatured and 1 mg/kg SRG-treated) and SRG100 (ligatured and 100 mg/kg SRG-treated). Vehicle or SRG solution was applied daily for 14 days and then all experimental rats were sacrificed. To examine the effect of SRG solution on periodontitis, the level of alveolar bone loss, cementum regeneration, gingival tissue degradation, and osteoclast cell numbers were analyzed. Results: Alveolar bone loss was inhibited in ligature-induced periodontitis rats treated with SRG treatment. Histopathological cementum was recovered in SRG1 and SRG100 groups. SRG extract inhibited gingival tissue degradation induced by ligature. In addition, the numbers of osteoclast cells were decreased by treatment SRG in periodontitis rats. Conclusion: Taken together, these results suggest that SRG have inhibitory effects against periodontitis. Therefore, the steamed radix of Rehmanniae glutinosa has may be a potential alternative for periodontitis.

• Journal of Microbiology and Biotechnology
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• 제33권2호
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• pp.268-276
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• 2023

Alkyl butyrate with fruity flavor is known as an important additive in the food industry. We synthesized various alkyl butyrates from various fatty alcohol and butyric acid using immobilized Rhodococcus cutinase (Rcut). Esterification reaction was performed in a non-aqueous system including heptane, isooctane, hexane, and cyclohexane. As a result of performing the alkyl butyrate synthesis reaction using alcohols of various chain lengths, it was found that the preference for the alcohol substrate had the following order: C6 > C4 > C8 > C10 > C2. Through molecular docking analysis, it was found that the greater the hydrophobicity of alcohol, the higher the accessibility to the active site of the enzyme. However, since the number of torsions increased as the chain length increased, it became difficult for the hydroxyl oxygen of the alcohol to access the ^γO of serine at the enzyme active site. These molecular docking results were consistent with substrate preference results of the Rcut enzyme. The Rcut maintained the synthesis efficiency at least for 5 days in isooctane solvent. We synthesized as much as 452 mM butyl butyrate by adding 100 mM substrate daily for 5 days and performing the reaction. These results show that Rcut is an efficient enzyme for producing alkyl butyrate used in the food industry.

• 분석과학
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• 제20권3호
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• pp.251-254
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• 2007

수용액 내에서 환원제인 sulfurous acid와 휘발성이 강한 Os(III)을 반응시킨 후 생성된 비휘발성 Os(IV)을 inductively coupled plasma atomic emission spectrometry (ICP-AES)로 분석하였다. pH 2-10의 수용액에서 sulfurous acid와 Os(VIII)의 정량적 반응에 의하여 생성된 Os(VI)을 ICP-AES로 분석하였다. 동축형 분무기(concentric type nebulizer)에 의한 시료 도입 방법에서 sulfurous acid와 osmium은 반응 직후부터 안정한 신호를 나타내었으며 다양한 ICP-AES 조건에서 3회 반복 측정했을 때 재현성은 0.5-4.5%였으며, 검출 한계는 2.5-57.7 ng/g이었다.

• Journal of Electrochemical Science and Technology
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• 제14권4호
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• pp.326-332
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• 2023

The high cost of Si-based solar cells remains a substantial challenge to their widespread adoption. To address this issue, it is essential to reduce the production cost of solar-grade Si, which is used as raw material. One approach to achieve this is Si electrodeposition in molten salts containing Si sources, such as SiO₂. In this study, we present the pulse electrodeposition of Si in molten CaCl₂ containing SiO₂ nanoparticles. Theoretically, SiO₂ nanoparticles with a diameter of less than 20 nm in molten CaCl₂ at 850℃ have a comparable diffusion coefficient with that of ions in aqueous solutions at room temperature. However, we observed a slower-than-expected diffusion of the SiO₂ nanoparticles, probably because of their tendency to aggregate in the molten CaCl₂. This led to the formation of a non-uniform Si film with low current efficiency during direct current electrodeposition. We overcome this issue using pulse electrodeposition, which enabled the facile supplementation of SiO₂ nanoparticles to the substrate. This approach produced a uniform and thick electrodeposited Si film. Our results demonstrate an efficient method for Si electrodeposition in molten CaCl₂ containing SiO₂ nanoparticles, which can contribute to a reduction in production cost of solar-grade Si.

• 한국화재소방학회논문지
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• 제19권2호
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• pp.105-110
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• 2005

외부 복사열원(10, 15, 20, 25 및 $35kW/m^2$)에 노출된 난연처리된 목재의 탄화특성을 측정하기 위해 Douglas fir를 사용하였으며, 목재에 복사열원을 노출시키기 위해 Cone heater를 사용하였다. 시료의 크기는 $100mm\times100mm\times50m$로 Monoammonium phosphate, Sodium borate, Zinc borate를 이용하여 배합된 수용성 난연제에 의해 함침 처리된 목재(F2와 F4)와 비처리된 목재(N)를 사용하였다. 연구결과, 난연처리된 Douglas fir의 경우 비처리된 목재에 비해 탄화율이 외부 복사열원의 증가와 관계없이 현저히 낮음을 알 수 있었으며, 난연제의 함량 증가에 따라 탄화율이 낮게 나타났다. 비처리된 목재에 있어 연소속도가 상대적으로 큼을 알 수 있으며, 낮은 외부 복사열원에서 보다 높은 복사열원에서 그 차이가 많이 남을 알 수 있다. 또한, 외부 복사열원이 $35kW/m^2$일 때 평균 탄화속도는 비처리된 목재가 난연처리된 목재에 비해 약 2배정도 빠름을 알 수 있었다 탄화율, 연소속도 및 탄화깊이와 속도의 측정결과 본 연구에서 배합된 난연성 수용액은 탄화층에 의한 단열 효과 및 불꽃 억제 효과가 있음을 알 수 있었다.

• 한국의상디자인학회지
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• 제9권3호
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• pp.47-57
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• 2007

This study focused on the properties natural dyeing and natural material and on the development of functional material for well-being in apparel industry. Comus officinalis Siebold et Zuccarini is used as natural dyeing material which had been reported that have curable effect for unbalanced immunity, geriatric diseases like urinary tract system, diabetes, hypertension, arthritis, tinnitus, hyperhidrosis and women's diseases like hypermenorrhea. And this material also has anti-cancer effect so that can restraint cancer cells. 3 kinds tester of cotton, wool and silk are dyed by boiled with each dye (flower, fruits, bark of tree) as first dyeing and dried in the shade. These testers are done by post-mordanting method. Aluminium Potassium(Alk(SO4)2), Cuprie Sulfate($CuSO4{\cdot}5H2O$), Stannous Chloride($SnCl2{\cdot}2H2O$), Ferrous Sulfate($FeCl2{\cdot}4H2O$), Titanium Sulfate 24% aqueous solution(Ti(SO4)2) are used as mordants. Dyeing results of Comus officinalis Siebold et Zuccarini flower and bark are shown as yellow color series. And dyeing result of fruits is pink color series. Silk shows the best dyeing property. As the point of view for dyeing property, Ti, Sn, Fe would be the properchoice for mordant. Following results are extracted in this study. Yellow color is resulted in dyeing with Cornus officinalis flower as non-mordanting condition. Yellowish red color is come from dyeing with Comus officinalis fruit as non-mordanting condition. Grayish yellow tone is resulted in dyeing with bark as non-mordanting condition. Orange tone color with Ti-mordanting, green tone color with Sn-mordanting and gray tone color with Fe-mordanting is resulted respectively. However light-fastness of Comus officinalis(flower, fruit, bark) is very low as 1 or 2 level in non-mordanting condition, Comus officinalis flower dyeing is turned out 3 or 4 level and fruit dyeing is 4 or 5 level, bark dyeing is 2 or 3 level with Ti-mordanting respectively. Eventually Comus officinalis fruit has the best light-colorfastness property among all of dyes. dry cleaning colorfastness of Cornus officinalis(flower, fruit, bark) is good as 4 or 5 level in Ti-mordanting condition, perspiration-colorfastness of Cornus officinalis(flower, fruit, bark) is good as 4 or 5 level in Ti-mordanting condition, With these results, this study could conclude that dye-ability, colorfastness problem is getting better after mordanting process and practical usage would be possible.

• Journal of Applied Biological Chemistry
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• 제58권1호
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• pp.55-60
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• 2015

수출용 냉동딸기 제조 시 미생물학적 안전성 확보를 위한 수단으로 이산화염소수와 acetic acid 병합처리를 최적 비가열 전처리 기술로써 적용하여 -20, -70, $-196^{\circ}C$로 냉동한 후 미생물 수, 품질변화 및 관능평가를 조사하였다. 냉동방법 및 세척 처리에 따른 색도 차이는 나타나지 않았고, 비타민 C 함량은 $-70^{\circ}C$ 냉동에서 35.33 mg/100 g FW로 가장 대조구와 유사하였으며, drip loss도 $-70^{\circ}C$ 냉동이 14.39%로 가장 낮게 나타났다. 관능평가 역시 $-70^{\circ}C$ 냉동이 -20, $-196^{\circ}C$ 냉동보다 높은 점수를 받았으며, 세척처리는 비타민 C 함량, drip loss 및 관능평가에 큰 영향을 끼치지 않는 것으로 나타났다. 또한, 냉동딸기에 50 ppm 이산화염소수와 1% acetic acid를 병합 처리하여 냉동 후 미생물 수 변화를 측정한 결과, 냉동 전과 같이 병합처리 된 딸기 시료에서 미생물이 검출되지 않았다. 따라서 저장성이 높은 수출용 냉동딸기 생산을 위해서는 gas nitrogen convection chamber를 이용한 $-70^{\circ}C$에서의 급속냉동 처리가 보다 효과적인 냉동방법이며, 냉동 처리만으로는 미생물 제어가 어렵기 때문에 냉동 전 비가열 전처리를 통해서 냉동딸기의 미생물학적 안전성을 확보해야 한다고 판단된다.

• 폴리머
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• 제30권6호
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• pp.512-518
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• 2006

양친성 블록공중합체는 생분해성 고분자인 poly((R)-3-hydroxybutyrie acid), PHB와 친수성 고분자인 poly(ethylene glycol), PEG를 이용하여 제조되었다. 미생물에 의해 생산된 분자량이 수십만인 PHB는 약물전달용 재료로 적합하지 않으므로 산 촉매 가수분해를 통해 분자량이 $3000{\sim}30000$을 가지도록 조절되었다. 공중합체를 수용액에 넣으면, 고분자들은 자기 조립에 의해 친수성인 PEG가 소수성인 PHB를 감싸는 형태의 고분자 미셀을 형성한다. 형성된 고분자 미셀은 생분해성과 생체적합성을 가지면서 생체 내에서 낮은 독성과 환자 친화적인 특성을 가지므로 약물 전달체로의 이용이 가능하다. 양친성 블록 공중합체는 PHB에 PEG를 도입한 것으로 에스테르교환(transesterification) 반응을 통해 유도되었다. PEG는 친수성 블록의 형성과 반응성을 향상시키기 위해 말단의 작용기를 개질한 후 사용되었다. 양친성 블록 공중합체 형성에 대한 열적 특성과 화학적 구조 분석은 DSC, FTIR, $^1H-NMR$을 사용하여 알아보았다. 임계 미셀 농도(critical micelle concentration, CMC)는 고분자 미셀이 형성되는 시점으로 형광 분광기를 사용하여 분석한 결과 $5{\times}10^{-5}g/L$ 부근에서 측정되었다. 수용액 상의 고분자 미셀은 냉동 건조 후, 분말형태의 나노입자를 얻었다. 고분자 미셀의 크기는 dynamic light scattering으로 측정한 결과 약 130 nm 정도로 나타났다. 또한 atomic force microscopy 측정을 통해 크기가 약 130 nm 정도인 구형 입자를 확인하였다. 나노입자가 형성된 고분자 미셀은 소수성 약물을 담지하여 수동적 표적지향형 약물 전달용 수송체로 이용이 가능할 것이다.