• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.580-585
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• 1991

Quinolone derivatives have been used as antibacterial agents. In this work, the competitive C-and O-acylation reaction of 3,4-dichloroacetophenone, as a model study for the synthesis of quinolone intermediate, is studied. The effects of various bases, solvents and the leaving groups of acylating agents on the ratio of C-versus O-acylation of 3,4-dichloroacetophenone are elucidated by means of employing ethylchloroformate, ethylphenylcarbonate and diethylcarbonate as acylating agents. In aprotic solvents, C-acylation reactions occur more predominantly as the size of metal ions composing bases becomes smaller. Regarding the effects of leaving groups, it is shown that C-acylation product is increased as the ability of leaving groups of acylating agents decreases. The ratio of C/O-acylation is also observed to be increased as the polarity of solvents decreases.

• Korean Journal of Materials Research
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• v.10 no.11
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• pp.732-737
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• 2000

Plasma enhanced chemical vapor deposition of $TiO_{2$\pm}{\delta}$ has been carried out using TEMAT [tetrakis(ethylmethylamido) titanium] and $H_2$. Increasing the power from 300 W to 500 W produced the high density plasma, leading to the formation of TiO$_2$films with an increased ratio of Ti to O and a negligible amount of C and N. Applying the bias of 30W to the substrate in creased the growth rate of the film with a slightly increased content of Ti in the film. In addition, $H_2O$ was from either the residual gas in the gase pressure or $H_2(/He)$ gas and actively participated in the formation of $TiO_2$ films. Consequently, Ti ions created in the plasma could be a main contributor to $TiO_2$ formation with a slight amount of $H_2O(~10^{-4}Toor)$ in the ambient, which provided the dissociation of TEMAT.

• Nano
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• v.13 no.12
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• pp.1850148.1-1850148.9
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• 2018

The interconnected three-dimensional Ni-Co-S nanosheets were successfully deposited on ZnO nanorods by a one-step potentiostatic electrodeposition. The Ni-Co-S nanosheets provide a large electrode/electrolyte interfacial area which has adequate electroactive sites for redox reactions. Electrochemical characterization of the ZnO@Ni-Co-S core-shell nanorods presents high specifc capacitance (1302.5 F/g and 1085 F/g at a current density of 1 A/g and 20 A/g), excellent rate capabilities (83.3% retention at 20 A/g) and great cycling stability (65% retention after 5000 cycles at a current density of 30 A/g). The outstanding electrochemical performance of the as-prepared electrode material also can be ascribed to these reasons that the special structure improved electrical conductivity and allowed the fast diffusion of electrolyte ions.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.235-241
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• 2023

Hyaluronidase (HAase) can enhance drug diffusion and dissipate edema by degrading hyaluronic acid (HA) in the extracellular matrix into unsaturated HA oligosaccharides in mammalian tissues. Microorganisms are recognized as valuable sources of HAase. In this study, a new hyaluronate lyase (HAaseD) from Bacillus sp. CQMU-D was expressed in Escherichia coli BL21, purified, and characterized. The results showed that HAaseD belonged to the polysaccharide lyase (PL) 8 family and had a molecular weight of 123 kDa. HAaseD could degrade chondroitin sulfate (CS) -A, CS-B, CS-C, and HA, with the highest activity toward HA. The optimum temperature and pH value of HAaseD were 40℃ and 7.0, respectively. In addition, HAaseD retained stability in an alkaline environment and displayed higher activity with appropriate concentrations of metal ions. Moreover, HAaseD was an endolytic hyaluronate lyase that could degrade HA to produce unsaturated HA oligosaccharides. Together, our findings indicate that HAaseD from Bacillus sp. CQMU-D is a new hyaluronate lyase and with excellent potential for application in industrial production.

• Advances in nano research
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• v.15 no.5
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• pp.441-449
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• 2023

Heavy metals, widely present in the environment, have become significant pollutants due to their excessive use in industries and technology. Their non-degradable nature poses a persistent environmental problem, leading to potential acute or chronic poisoning from prolonged exposure. Recent research has focused on separating heavy metals, particularly from industrial and mining sources. Industries such as metal plating, mining operations, tanning, wood and chipboard production, industrial paint and textile manufacturing, as well as oil refining, are major contributors of heavy metals in water sources. Therefore, removing heavy metals from water is crucial, especially for safe water supply in swimming and water sports. Iron oxide nanoparticles have proven to be highly effective adsorbents for water contaminants, and efforts have been made to enhance their efficiency and absorption capabilities through surface modifications. Nanoparticles synthesized using plant extracts can effectively bind with heavy metal ions by modifying the nanoparticle surface with plant components, thereby increasing the efficiency of heavy metal removal. This study focuses on removing lead from industrial wastewater using environmentally friendly, cost-effective iron nanoparticles synthesized with Genovese basil extract. The synthesis of nanoparticles is confirmed through analysis using Transmission Electron Microscope (TEM) and X-ray diffraction, validating their spherical shape and nanometer-scale dimensions. The method used in this study has a low detection limit of 0.031 ppm for measuring lead concentration, making it suitable for ensuring water safety in swimming and water sports.

• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.618-628
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• 1998

Pure CaO, Mn-doped CaO, Mn/CaO, and K/CaO catalysts were prepared and tested as catalysts for the oxidative coupling of methane in the temperature range of 600 to 800$^{\circ}C$ to investigate the effects of Mn- and K-addition on the catalytic activity of calcium oxide. To characterize the catalysts, X-ray powder diffraction(XRD), XPS, SEM, DSC, and TG analyses were performed. The catalytic reaction was carried out in a single-pass flow reactor using on-line gas chromatography system. Normalized reaction conditions were generally $p(CH_4)/p(O_2)=250$ Torr/50 Torr, total feed flow rate=30 mL/min, and 1 atm of total pressure with He being used as diluent gas. Among the catalysts tested, 6.3 mol% Mn-doped CaO catalyst showed the best $C_2$ yield of 8.0% with a selectivity of 43.2% at 775$^{\circ}C$. The $C_2$ selectivity increased on lightly doped CaO catalysts, while decreased on heavily doped CaO([Mn] > 6.3 mol%) catalysts. 6 wt.% Mn/CaO and 6 wt.% K/CaO catalysts showed the $C_2$ selectivities of 13.2% and 30.9%, respectively, for the reaction. Electrical conductivities of CaO and Mn-doped CaO were measured in the temperature range of 500 to 1000$^{\circ}C$ at Po2's of $10^{-3}\; to\;10^{-1}\;atm.$ The electrical conductivity was decreased with Mn-doping and increased with increasing $P0_2$in the range of $10^{-3}\;to\;10^{-1}\;atm,$ indicating the specimens to be p-type semiconductors. It was suggested that the interstitial oxygen ions formed near the surface can activate methane and the formation of interstitial oxygen ions was discussed on the basis of solid-state chemistry.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.147-152
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• 1991

양단이 고정된 보가 변형할 때에는 중간 평면의 신장을 수반하게 된다. 운동 의 진폭이 증가함에 따라 이 신장이 보의 동적 응답에 미치는 영향은 심각 하게 된다. 이러한 현상은 응력과 변형도와의 관계가 선형적이라 하더라도 변형도와 변위와의 관계식은 비선형이 되며 결국은 보의 비선형 운동방정식 을 낳게된다. 보는 연속계이긴하지만 근사를 위하여 다자유도계로 간주할 수 있다. 비선형 다자유도계에 있어서는 선형화된 계의 고유진동수끼리 적절한 관계를 가질 때 내부공진이 발생할 수 있다. 양단이 고정된 곧은 보의 비선 형 동적응답이 그동안 많이 연구되어 오고 있으며, 집중질량을 가지고 직각 으로 굽은 보의 해석을 위하여 내부공진을 고려한 해석적 혹은 실험적 연구 가 이루어져 왔다. 그중에서도 Nayfeh등은 조화가진 하의 핀과 꺾쇠로 고정 된(hinged-clamped) 보의 정상상태응답을 해석하기 위해 두 모우드 사이의 내부공진을 고려하였다. 이 연구에서는 세 모우드 사이의 내부공진을 고려하 여 강제진행 중인 보의 비선형 해석을 다루고자 한다. 이 문제에 관심을 갖 게 된 동기는 "연속계의 비선형 해석에서 더 많은 모우드를 포함시키면 어 떤 결과를 낳게 될 것인가\ulcorner"라는 질문에서 생겨난 것이다. 갤러킨 법을 이용 하여 비선형 편미분 방정식과 경계 조건으로 표현되는 이 문제를 연립 비선 형 상미분 방정식으로 변환한다. 다중시간법(the method of multiple scales) 을 이용하여 이 상미분 방정식을 정상상태에서의 세 모우드의 진폭과 위상 에 대한 연립비선형 대수방정식으로 변환한다. 이 대수방정식을 수치적으로 풀어서 정상상태 응답을 구하고 Nayfeh등의 결과와 비교한다. 결과와 비교한다. studies, the origin of ${\alpha}$$_1$peak was attributed to the detrapping process form trap with 2.88[eV] deep of injected space charge from the chathode in the crystaline regions. The origin of ${\alpha}$$_2$ peak was regarded as the detrapping process of ions trapped with 0.9[eV] deep originated from impurity-ion remained in the specimen during production process of the material, in the crystalline regions. The origin of ${\beta}$ peak was concluded to be due to the depolarization process of "C=0"dipole with the activation energy of 0.75[eV] in the amorphous regions. The origin of ${\gamma}$ peak was responsible to the process combined with the depolarization of "CH$_3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorp

• The Korean Journal of Physiology
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• v.17 no.2
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• pp.119-124
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• 1983

The in vivo and in vitro buffer capacities of true plasma and tissue buffer capaciies were compared on dogs. Intracellular pH was determined on skeletal muscle by a modification of the method of Schloerb and Grantham using $C^{14}$ DMO. The in vivo curve for plasma or extracellular fluid has a much lower slope than the in vitro curve. The in vivo slope of skeletal muscle in the dog is approximately 20 sl. The slope for skeletal muscle in vivo falls between the in vitro and in vivo slopes of true plasma. It appears that intracellular hydrogen ion varies linearly with extracellular hydrogen ion when $CO_2$ tension is changed. Both hydrogen ion gradient and Hi/He ratio vary in skeletal muscle, with an increase in $CO_2$ tension. Infusion of 0.3N HCl gave two distinct patterns, the $H_i-H_e$ gradient decreased; and it would appear that very little hydrogen ion as such penetrated to the inside of the cells during the time of observation. Although lactic acid presumably enters the cell and the same of larger load was given as was used for hydrochloric acid, only very mild intracellular acidosis resulted, ostensibly due to metabolism of this substrate. Gluconic acid produced a more severe acidosis, both intracellularly and extracellularly, but with both of these acids the hydrogen ion gradient decreased and the $H_i/H_e$ ratio also decreased. The experiments on the dogs with hemorrhagic shock the hydrogen ion increase producing the acidosis originates inside the cells. Even so, the hydrogen ion gradient increased only very slightly in the acute experiments. This may suggest that even over short intervals of time skeletal muscle cells have a capacity to pump out hydrogen ions at a rate which maintains approximately the normal $H_i/H_e$ gradient when the source of the hydrogen ion is in the interior of the cell.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1992.10a
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• pp.113-116
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• 1992

소음의 발생 원인은 공기역학적 측면과 구조적 측면으로 나누어지는데, 실제 로는 유동장에서 발생되는 음원과 구조물에서 발생되는 진동과의 상호 간섭 에 의해 보다 복잡한 형태로 발생된다. 음장 문제를 두가지 범주로 구분하면 첫째는 음원과 구조물과의 상호교란에 의한 산란문제(Scattering)와 둘째로 구조물의 자체 진동에 의한 음의 전파현상과 구조물내부에 회전체와 같은 음원이 존재하는 경우에 음의 전파를 관측하는 방사문제(Radiation)가 있다. 실제로 산업용 터빈이나 비행기 엔진 흡입구에서 발생되는 소음, 또는 자동 차의 배기구를 통해 발생되는 소음 그리고 엔진의 진동에 의한 구조적 소음, 기타 가전제품의 회전체(Fan & Motor)에 의한 소음은 방사(Radiation)의 문 제로서 중요 관심 과제이다 수치적 기법으로 근래에 많이 사용하는 방법으 로 BEM(경계요소법), FEM(유한요소법), FDM(유한차분법)이 있는데 본 연 구에서는 유한요소법을 이용하기로 한다. 지금까지는 주로 BEM을 통해서 Far-Field의 음향장을 해석하였지만 복잡한 형상을 갖는 구조물내부에서의 음향장 변화나 구조물 내부에 음원이 존재하는 경우 또는 구조물 자체가 갖 는 물리적 특성치 변화 즉 물체표면에서의 부분 진동문제의 음향장 해석에 있어서 가장 잘 대체해 나갈 수 있는 방법이 유한 요소법이라고 여겨진다. 본 연구에서는 2차원 또는 기하학적으로 축대칭인 3차원 Duct내부에 음원이 존재하는 경우 음원전파에 따른 Near-field와 far-field에서 음의 방향성을 예측하기 위해 먼저 기본적인 유한요소법에 의한 Robin 경계조건을 사용하 여 계산된 결과와 Infinite Element를 도입하여 계산할 결과를 비교하여, Infinite Element가 보다 효율적이며 타당한 결과를 얻음을 확인해 보기로 한다.다 복합적인 측면에서 치료에 임하여야 할 것으로 사료된다. with such configuration.trap with 2.88[eV] deep of injected space charge from the chathode in the crystaline regions. The origin of ${\alpha}$$_2$ peak was regarded as the detrapping process of ions trapped with 0.9[eV] deep originated from impurity-ion remained in the specimen during production process of the material, in the crystalline regions. The origin of ${\beta}$ peak was concluded to be due to the depolarization process of "C=0"dipole with the activation energy of 0.75[eV] in the amorphous regions. The origin of ${\gamma}$ peak was responsible to the process combined with the depolarization of "CH$_3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorphous regions.의 증발산율은 우기의 기상자료를 이용하여 구한 결과 0.05 - 0.10 mm/hr 의 범위로서 이로 인한 강우손실량은 큰 의미가 없음을 알았다.재발이 나타난 3례의 환자

• Korean Journal of Microbiology
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• v.30 no.4
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• pp.260-264
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• 1992

Pseudotnorju.c sp. EL-071P degrading 2.4.5-trichlorophe~~oxyi~cetaicci d (2.3.5-T) was resistantto antibiotics: rifampicin. ampicillin. kanamycin and metal ions : Zn" and Cu".The plasmitl related to the degradation of 2.4.5-'r and rifa~npicin resistance was isolatecifrom the strain. Its size was about 40 Kb. As result of transforming the plasmid intoEsch~rirhiti coli MClOhl, it was confirmed that the plasmid ura.; related to 2.4.5-T degradation.The strain coulil grow in the various chlorinated aromatic analogs as the solc carbon source.In the case of chlorophcnols. the chlorinated mono-substituteti phenols were easily dcgradetlin the order ol' ortho-. ~ ~ a r um- ,c ~tu-position.T he 2.3.5-T mctaholism was inhibited by 4-chlorophenol of 2.4.5-7' analog. In non-chlorinateci aromatics. ~ C I I L O ~ I ~ Csa.l icylilte i~ndtoluene were uscd ax the carbon source by the strain and typestrain Acudonlotrtr.\ plrtirltrKCTC 1643 having clegrad;~bility of various aromatics. But naphtalene was usecl only bythe A~urlomonri.\ sp. EL-07 1 P.the A~urlomonri.\ sp. EL-07 1 P.