• 한국수소및신에너지학회논문집
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• 제15권4호
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• pp.283-290
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• 2004

The single-step process for conversion of syngas to DME give higher conversion than the syngas-to-methanol process. This arises because of a synergy among the three simultaneous reaction, methanol synthesis, methanol dehydration and water gas shift reaction, in the process. we would find the optimal condition of the process which these advantages. The optimal condition of DME synthesis reaction over a commercial $Cu/Zn/Al_2O_3$ catalyst and Hybrid catalyst in a fixed bed reactor. The syngas-to-dimethyl ether conversion was examined on various reaction condition (Temperature 473~553K, $H_2/CO$ ratio 1~3, Pressure 30'50atm, GHSV 1000~4000).

• 한국분말재료학회지
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• 제23권2호
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• pp.143-148
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• 2016

A microfluidic reactor with computer-controlled programmable isocratic pumps and online detectors is employed as a combinatorial synthesis system to synthesize and analyze materials for fabricating CdSe quantum dots for various applications. Four reaction condition parameters, namely, the reaction temperature, reaction time, Cd/Se compositional ratio, and precursor concentration, are combined in synthesis condition sets, and the size of the synthesized CdSe quantum dots is determined for each condition. The average time corresponding to each reaction condition for obtaining the ultraviolet-visible absorbance and photoluminescence spectra is approximately 10 min. Using the data from the combinatorial synthesis system, the effects of the reaction conditions on the synthesized CdSe quantum dots are determined. Further, the data is used to determine the relationships between the reaction conditions and the CdSe particle size. This method should aid in determining and selecting the optimal conditions for synthesizing nanoparticles for diverse applications.

• 한국세라믹학회지
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• 제46권6호
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• pp.615-620
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• 2009

The present research was performed to determine the optimal firing condition and holding time for malayaite crystal, which is responsible for the stable pink-red coloration in glaze at high temperatures, using Cr$Cl_3$ as chromophore for the synthesis of $Cr_2O_3-SnO_2-CaO-SiO_2$ system pigments. The malayaite crystal was influenced by the raw materials used for synthesis, firing temperature, and holding time. Thus there are differences in the crystal phase and in the coloration according to the condition of synthesis. When Cr$Cl_3$ was used as chromophore, the pigment could be synthesized at lower temperatures, because Cr$Cl_3$ melts at $1500{^{\circ}C}$, which is much lower than the temperature at which $Cr_2O_3$ melts (higher than $2435{^{\circ}C}$). And the employed Cr ion showed a change in oxidation state. When a mineralizer was used to improve the employment of malayaite and the Cr ion, and the low temperature was maintained at which the malayaite crystal is produced, the production of malayaite crystal was promoted and the employment of chromophore was also promoted in the oxidation state of Cr (IV). The results of the experiment showed that the optimal firing condition was 18 h of holding time at $800{^{\circ}C}$, using Cr$Cl_3$ as chromophore, followed by 2 h at the raised temperature of $1150{^{\circ}C}$. The change in coloration of the Cr (IV) employed by malayaite showed a very rich color of red. Thus it was possible to effectively synthesize sphene-pink pigments with more red tint at a low temperature.

• Journal of Microbiology and Biotechnology
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• 제5권1호
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• pp.22-25
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• 1995

Bacillus licheniformis SSA3 can produce a dark-brown antimutagenic pigment. The optimal conditions for production of this pigment are reached at 0.1% tyrosine, in pH 6-8, within 7-9 days, at $30^{\circ}C$, and in aerobic condition. We cloned a DNA fragment involved in pigment synthesis from Bacillus licheniformis SSA3 using a mutant strain. The cloned DNA was 7kb in size, which can produce the same pigment even in E. coli.

• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1141-1145
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• 2008

Isomaltooligosaccharide (IMO) is a promising dietary component with prebiotic effect, and the long-chain IMOs are preferred to short chain ones owing to the longer persistence in the colon. To establish the optimal process for synthesis of long-chain IMOs, we systematically examined the reaction condition of dextransucrase of Leuconostoc mesenteroides B-512F by changing the ratio of sucrose to maltose (varying as 1:4, 1:2, 1:1, and 2:1) and amount of each sugar (from 2% to 20%). As a result, a ratio of 2:1 (sucrose to maltose, 10:5% or 20:10%, w/v) was determined as an optimal condition for long-chain IMO synthesis (DP3-DP9) with relatively higher yields (70-90%, respectively).

• 한국군사과학기술학회지
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• 제5권4호
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• pp.49-56
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• 2002

For the purpose of the increase in the performance and thermal stability of PBX's, the mixed formal consisting of BDNPF, DNPBF and BDNBF were synthesized. In order to find out the optimal condition for the synthesis of energetic plasticizer, BDNPF, DNPBF and BDNBF, the synthetic procedures have been investigated. We synthesized DNP-OH and DNB-OH through oxidative nitration and controlled various composition of mixed formal by $H_{2}SO_{4}$ and s-trioxane to investigate optimal composition, and then characterized its thermo-physical properties.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.109-110
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• 2007

Pyrrole and DNA can be used for synthesis of conducting nanowires. Protonated pyrrole and negatively charged DNA are absorbed by electrostatic interaction. The level of absorbance is related to pH of pyrrole. Therefore, DNA immobilized and aligned on the 3-aminopropyltrimethoxysi1ane (APTES) modified Si surface. Positive pyrrole monomers was deposited on aligned DNA for the synthesis of nanowire in various pH condition. And polypyrrole nanowires were synthesized by polimerization with ammonium persulfate (APS). These polypyrrole nanowires were measured by AFM, and then we found optimal pH level for the synthesis of nanowires.

• 약학회지
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• 제41권5호
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• pp.595-601
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• 1997

The optimal synthesis condition based on the yield of thiamine mononitrate has been attained according to Box-wilson experimental design. The optimal condition was as follows : Molar concentration ratio of $SB1{\cdot}HCL=0.6839$, quantity of $NH_4NO_3=50.09g$, agitation velocity=51.6rpm, reaction temperature=22.8$^{\circ}C$. The stabilities of three kinds of thiamine monosalts(thiamine monoiodide, -monobromide, -monorhodanate) were investigated in sterile solution, compressed tablet and multivitamin capsule, respectively. Assay data are given to show that thiamine monosalts are not significantly higher than that of thiamine mononitrate in sterile solutions and the addition of an acidic stabilizer is unnecessary. The solutions were clear and free of precipitate and didn't discolored after storage at room temperature and 40$^{\circ}C$ for 6 months. The tablets and capsules were assayed initially and at predetermined intervals during storage at room temperature and 40$^{\circ}C$ for 6 months. Thiamine monorhodanate was found to be more stable than other thiamine monosalts in these compressed tablets containing other vitamin of the B complex and the data indicate that thiamine monosalts was similar to that of thiamine mononitrate in the multivitamine capsules.

• 한국응용과학기술학회지
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• 제39권1호
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• pp.1-9
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• 2022

항균력과 보습력을 동시에 가지고 있는 화장품용 첨가제인 1, 2-octanediol (OD)의 피부 문제점을 개선하기 위하여 galactoside 유도체인 1, 2-octanediol galactoside (OD-gal)를 대장균 β-galactosidase (β-gal)을 이용하여 합성하였다. 이 때, β-gal은 4.5 U/ml, OD 농도는 150 mM, pH는 7.0, 그리고, 온도는 37℃가 OD로부터 OD-gal을 합성하는 최적 조건이었다. 이 조건에 24 시간 동안 150 mM의 OD로부터 약 55.9 mM의 OD-gal이 합성되었고, 이 때, conversion 수율(mole 기준)은 약 37.2% 였다. 또한, 9 ml의 반응액에서 67.4 mg의 순수한 OD-gal을 정제할 수 있었으며, 반응액에 들어 있는 OD에서부터 정제를 포함하는 전체 합성수율은 weight 기준으로는 약 34.1% 이고, mole 기준으로는 약 16.2% 정도였다. 이러한 연구결과는 보다 안전한 화장품용 첨가제로서 OD-gal의 산업화에 기초자료로서 도움을 줄 것으로 생각된다.

• 한국세라믹학회지
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• 제33권4호
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• pp.418-424
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• 1996

(Ti.W)C complex carbide was synthesized by self-propagating high temperature synthesis (SHS) chemical furnace. Attempt to find the optimal condition for synthesis of (Ti.W)C the effects of molar ratio of Ti:W:C on the synthesized powders and mechanical properties were investigated, Optimum molar ratio of these synthe-sized powder was Ti:W:C=0.7:0.2:1.0 The bulk density M,O.R Hardness Fracture toughness of (Ti.W)C complex carbide sintered at 200$0^{\circ}C$ for 60 min by hot-pressing under the pressure of 20 MPa were 7.6g/cm3, 475 MPa, 17,.7 GPa respectively.