• 융합신호처리학회논문지
• /
• 제11권1호
• /
• pp.80-87
• /
• 2010

함수합성법은 주어진 입출력 데이터 쌍으로부터 입출력관계를 충족하는 함수를 예측하는 것으로, 특성을 알 수 없는 시스템을 제어할 때에 필수적이다. 일반적으로 시스템은 비선형인 성질을 갖는 경우가 많고, 함수 합성에 취급하는 변수, 정수, 제약 등으로 조합된 문제가 발생하기가 쉽다. 그 함수를 합성하는 방법 중 한 가지로 유전적 프로그래밍이 제안되고 있다. 이것은 함수를 트리구조로 표시한 함수 트리에 유전적 조작을 적용하여, 입출력 관계를 충족하는 함수 트리를 탐색하는 방법이다. 본 논문에서는 기존의 유전적 프로그래밍에 의한 함수 합성법의 문제점을 지적하고, 새로운 4종류의 개선법을 제안한다. 즉, 함수 트리를 탐색할 때에 함수가 복잡하게 되는 것을 방지하기 위하여 함수 트리의 성장 억제, 조기 수렴을 목표로 하는 국소 탐색법의 채택, 함수 트리 내의 필요 없이 길어지는 요소의 효과적인 삭제, 대상으로 하는 문제의 특성을 이용하는 방법이다. 이러한 개선법을 이용할 경우, 기존의 유전적 프로그래밍에 의한 함수 합성법보다도 짧은 시간에 우수한 구조의 함수 트리가 구해지는 것을 2-spirals 문제에 대하여 컴퓨터 시뮬레이션을 통하여 확인하였다.

• 한국분말재료학회지
• /
• 제25권2호
• /
• pp.132-136
• /
• 2018

Core/shell CdSe/ZnS quantum dots (QDs) are synthesized by a microfluidic reactor-assisted continuous reactor system. Photoluminescence and absorbance of synthesized CdSe/ZnS core/shell QDs are investigated by fluorescence spectrophotometry and online UV-Vis spectrometry. Three reaction conditions, namely; the shell coating reaction temperature, the shell coating reaction time, and the ZnS/CdSe precursor volume ratio, are combined in the synthesis process. The quantum yield of the synthesized CdSe QDs is determined for each condition. CdSe/ZnS QDs with a higher quantum yield are obtained compared to the discontinuous microfluidic reactor synthesis system. The maximum quantum efficiency is 98.3% when the reaction temperature, reaction time, and ZnS/CdSe ratio are $270^{\circ}C$, 10 s, and 0.05, respectively. Obtained results indicate that a continuous synthesis of the Core/shell CdSe/ZnS QDs with a high quantum efficiency could be achieved by isolating the reaction from the external environment.

• 한국동물학회지
• /
• 제34권2호
• /
• pp.148-158
• /
• 1991

마우스의 악하선 세포를 배양하기 위하여 악하선 조직으로부터 세포를 분리하는 조건과 분리된 세포의 배양조건을 조사하였다. 세포분리에는 0.25% trypsin을 사용하였으며 배양액은 여러 농도의 fetal bovine serum (FBS) 또는 low protein serum replacement(LPSR)가 첨가된 Dulbecco's modified Eagle's medium(DME) 이었다. 배양된 세포의 대부분 상피형 세포로 확인 되었으며, 배양시 5-10%의 FBS를 첨가하였을 경우에 가장 높은 DNA합성능을 보였으나 이보다 높은 농도의 FBS 첨가시에는 오히려 DNA 합성능이 저하되었다. 혈청 대체물인 LPSR 첨가에 의한 악하선 세포를 배양 했을 때 population doubling time은 42.5 시간이었고 세포의 포화밀도는 1.2 $\times$10 5 cells / $cm^2$이었다. Dihydrotestosterone (DHT)은 악하선 배양세포의 DNA 합성에 관여하지 않거나, 관여한다면 DNA 합성을 억제하는 것으로 보였다. 이에 반해 Thyroxine (T4)은 악하선 배양세포의 DNA 합성을 현저히 증가시켰다. T4와 DHT 모두다 배양세포의 단백질 합성능을 증가시켰다. 또한 이 호르몬들이 악하선 배양세포의 epidermal growth factor(EGF) 분비를 증가시킨 결과는 DHT와 T4는 악하선 세포의 EGF 생산 뿐만 아니라 EGF 분비의 조절에도 관련되어 있음을 시사한다. 본 실험에서 정해진 악하선 세포의 배양조건은 악하선 세포의 증식과 기능의 변조를 탐구하는데 유용하게 응용될 수 있을 것으로 생각된다.

• 대한화학회지
• /
• 제56권2호
• /
• pp.246-250
• /
• 2012

An efficient access, single step and environmentally benign synthesis of a new series of pyrazole containing isoxazolines derivatives were prepared by the condensation of chalcones bearing pyrazole moiety with hydroxyl amine hydrochloride in basic condition by using polyethylene glycol-400 (PEG) as a greener reaction solvent. The advantages of the present methodology are mild reaction condition and avoidance of volatile organic solvent. Furthermore, these newly synthesized compounds were screened for their antimicrobial activity against various pathogens like Escherichia coli (MTCC 2939), Salmonella typhi (MTCC 98), Staphylococcus aureus (MTCC 96), Bacillus subtilis (MTCC 441), Aspergillus niger (MTCC 281), Aspergillus flavus (MTCC 2501), Penicillium chrsogenum (MTCC 160) and Fusarium moniliformae (MTCC 156). Especially compound containing the hydroxyl group in C2-position and presence of halo (I, Br and Cl) groups as substituents at $C_3$ and $C_5$ position on the benzene nucleus showed the higher activity. Furthermore, compounds bearing methyl groups in combination with I and Br which enhanced the activity.

• 한국재료학회지
• /
• 제26권5호
• /
• pp.246-249
• /
• 2016

Nickel powders were prepared under solvothermal condition by precipitation from metal nitrates with aqueous ammonium hydroxide. The powders were obtained at in a temperature range of $190-250^{\circ}C$ for 6h. The morphology and size of nickel powders were studied as a function of reaction temperature. The synthesis of nickel crystalline particles is possible under a solvothermal conditions in ethylene glycol solution. Characterization of the synthesized nickel powders were studied by XRD, SEM(FE-SEM) and TG/DSC. X-ray diffraction analysis of the synthesized powders indicated the formation of nickel structure after reaction. The average crystalline sizes of the synthesized nickel powders were in the range of 200-1000 nm; and the distribution of the powders was broad. The shape of the synthesized nickel particles was almost spherical. The morphology of synthesized nickel powders changed with reaction condition. It was possible to synthesize nickel powders directly in ethylene glycol without reducing agent.

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

• 한국분말재료학회지
• /
• 제11권4호
• /
• pp.294-300
• /
• 2004

This study for preparation of aluminum nitride (AlN) with high purity was carried out by self-propagating high-temperature synthesis method in two different systems, $Al-N_{2}$ and $Al-N_{2}$-AlN, with the change of nitrogen gas pressure and dilution factor. On the occasion of $Al-N_{2}$ system, unreacted aluminum was detected in the product in spite of high nitrogen pressure, 10 MPa, This may be caused by obstructing nitrogen gas flow to inner part of molten and agglomerate of aluminum, formed in pre-heating zone. In $Al-N_{2}$-AlN system, AlN with a purity of 95% or ever can be prepared in the condition of $f_{Dil}\geq0.5$, $P_{N_{2}}\geq$ 1 MPa, and the purity can be elevated to 98% over in the condition of $f_{Dil}$ = 0.7 and $P_{N_{2}}$ = 10 MPa.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 1998년도 춘계학술발표회 논문집
• /
• pp.120-127
• /
• 1998

It is very difficult to execute the vibration analysis of a huge strucutre, which takes up much time and expense. In this paper we intend to make the equivalent system of a local vibration system of a huge structure with a view to improving the dynamic characteristics and reducing time and expense. First of all, upper deck structure model is maded. And we perform the vibration analysis by the Substructure Synthesis Method and execute the exciting test for the upper deck structure model, and observe the coincidences of two results to confirm the reliability of the analyzing tools used. To make the equivalent system, we give boundary condition to sub-structure that want to be modified and execute the Sensitivity Analysis Method and the Optimum Structural Modification Method. And we execute the structural modification of the equivalent system.. The following can be found from this study. 1. The analytical results are generally coincident with each other. 2. The equivalent system of the superstructure model can be easily obtained using the sensitivity analysis metho and the optimum structural modification method. 3. The structural modification using the equivalent system can be obtained good results above 90% of object value.

• 약학회지
• /
• 제41권5호
• /
• pp.595-601
• /
• 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.

• 한국가스학회지
• /
• 제18권4호
• /
• pp.27-34
• /
• 2014

본 연구에서는 단열열량계의 일종인 폭발열량 측정장치를 이용하여 레졸수지 합성반응에서 온도조절 물질이 열폭주 특성에 미치는 영향을 평가하고, 반응열과 활성화에너지 등의 속도론적 데이터를 검토하였다. 그 결과, 온도조절 물질이 투입된 낮은 고형분 농도에서는 폭주반응의 격렬함을 나타내는 순간 특성치들이 감소했다. 그러나 투입된 온도조절 물질의 갑작스런 소실은 급격한 2차 폭주반응을 촉발시켰다. 이때, 레졸수지 합성반응의 폭주반응에 의한 반응열은 페놀을 기준으로 약 157 kJ/mol이었고, 활성화에너지는 약 60 kJ/mol로 나타났다.