• 대한화학회지
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• 제55권3호
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• pp.341-345
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• 2011

Schiff base 코발트(II) 착물, bis[4-chloro-2-((E)-(isopropylimino) methyl) phenol]cobalt(II), 을 합성하고 단결정 X-ray 회절 분석을 하였다. 코발트 (ii) 합성물의 현상학적, 속도론적 및 기계적 특성은 TG/DTG법으로 연구하였다. 실험 데이터에 기초하여, 활성화 에너지, 지수 앞자리인자, 활성화 엔트로피와 같은 속도론적 파라미터를 계산하였으며, 가장 가능성 있는 메카니즘 함수로는 $g({\alpha})={\alpha}^2$이 추정되었다. 따라서, 모든 분해 단계에서 속도 조절 단계는 1차원 확산 과정(Parabolic model) 이다.

• Bulletin of the Korean Chemical Society
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• 제15권12호
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• pp.1054-1058
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• 1994

Different behavior on the formation of soluble intermediate was observed depending on the substrate employed during the nucleation of lead dioxide from plumbous ion using a rotating ring-disk electrode. It was found that no soluble intermediate was formed at glassy carbon electrode, while the presence of soluble intermediate could be detected at platinum substrate. From the different anodic behavior of two substrates, the formation of a probable Pb(Ⅲ) soluble intermediate was suggested. A most probable nucleation mechanism at the platinum substrate involving a second order chemical reaction was derived on the basis of rotating disk electrode experiments.

• 한국환경농학회:학술대회논문집
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• 한국환경농학회 2011년도 30주년 정기총회 및 국제심포지엄
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• pp.188-195
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• 2011

Red lateritic soils are typically low in total organic carbon (TOC) and available phosphorus (AP) content and continuous fertilization is required to obtain desired crop yield. In this experiment, cattle manure in three forms (air-dried, composted and vermicomposted) were applied to red lateritic soil to study their effect on TOC and AP content of soil and probable mechanism of P-solubilization as affected by these treatments were also studied. Vermicompost was the most effective to solubilize insoluble P in red lateritic soil (Alfisols) as compared to other organic amendments (air-dried cattle manure and compost). The highest SPA in vermicompost-treated soil attributed to the comparatively higher concentration of all the three SPA isozymes in these soils. The maximum P-solubilization in these soils might be attributed to the highest SPA and presence of several organic acids like citric, lactic and oxalic acids in vermicompost-treated soils. Since, vermicompost application also increased TOC, mineralizable N and exchangeable K content of soil, vermicompost could be considered as the most rational organic amendment to improve chemical properties of red lateritic soils.

• 공업화학
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• 제1권1호
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• pp.52-62
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• 1990

폴리카보네이트 폴리올, MDI 및 N-methyldiethanolamine(MDEA)로부터 폴리카보네이트형 우레탄 수지를 합성하고, MDEA의 4차 암모늄염화 반응에 의해서 양이온성 폴리카보네이트 우레탄 수지를 제조하였다. 우레탄 연쇄내 이온기의 함량이 증가함에 따라 인장강도 탄성율은 현저하게 증가되었으나 내가수분해성등은 저하되는 경향을 표시하였다. 에탄올/물 혼합용액 분리실험에서 양이온성 폴리카보네이트형 우레탄 막의 선택도는 20정도였으며, 이때의 분리기구는 carrier mediated transport mechanism을 따른 것으로 생각된다.

• Journal of Mechanical Science and Technology
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• 제15권3호
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• pp.291-299
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• 2001

Recently, severe wear on the shutdown rod cladding of Ulchin Nuclear Power Plant #1, #2 were observed by the Eddy Current Test(E.C.T.). In particular, the wear at the sixth card location was up to 75%. The test results indicated that the Flow Induced Vibration(F.I.V.) might be the cause of the fretting wear resulting from the contact between Rod Cluster Control Assemblies(RCCAs) and their spacing cards(guide plates) arranged in the guide tube. From reviewing RCCAs fretting wear repots and analyzing the general characteristics of F.I.V. mechanism in the reactor, geometric layout and flow conditions around the control rod, it is concluded that the turbulence excitation is the most probable vibration mechanism of RCCA. To identify the governing mechanism of RCCA vibration, an experiment was performed for a representative rod position in which the most serious fretting wear experienced among the six rod positions. The experimental rig was designed and set up to satisfy the governing nondimensional numbers which are Reynolds number and mass damping parameter. The vibration amplitude measurement by the non-contact laser displacement sensor showed good agreements in the frequency and the maximum wearing(vibration) location with Ulchin E.C.T. results and Framatome report, respectively. The sudden increase in the vibration amplitude was sensed around the 6th guide plate with mass flow rate variation. Comparing the similitude rod behaviour with the idealized response of a cylinder in flow induced vibration, it was found that he dominant mechanism of vibration was transferred from turbulence excitation to periodic shedding at the mass flow ate 90ι/min. Also the critical velocity of the vibration in RCCAs was determined and the vibration can be prevented by reducing the bypass flow rate below the critical velocity.

• Environmental Analysis Health and Toxicology
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• 제23권1호
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• pp.33-39
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• 2008

The genotoxicity of mercury compounds have been investigated with a variety of genetic endpoints in prokaryotic and eukaryotic cells. The mercury ions are positively charged and easily form complexes with DNA by binding with negatively charged centers to cause mutagenesis. Further, the mercury ions can react with sulfhydryl (-SH) groups of proteins associated with DNA replication and alter genetic information. Another mechanism by which mercury damages DNA molecule is via its probable involvement of reactive oxygen species (ROS) and induces DNA strand breaks. In order to investigate whether the ROS production was induced by mercury, we performed ROS assay. As the result, the ROS production was significantly increased when it grows dose-dependently and time-dependently. We compared mercury alone-treated group and mercury co-treated with Vitamin C or glutathione group. As the result, the ROS production induced by mercury was decreased by Vitamin C and glutathione. Co-treated with Vitamin C and glutathione group was the most effective to lowering ROS production induced by mercury.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.441-444
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• 2006

Helicity in isotropic turbulence was well known to have intermittent fashion in their statistics. But its exact explanation about the onset of intermittency of helicity in turbulence did not give clearly yet. Most probable causes comes from the vortical motion of the fluids. Distribution of the angle between fluid velocity and vorticity have alignment tendency. This may be a clue to investigate intermittency of helicity. In this study, we aim to review and establish approaches to reveal the mechanism and the origin of intermittency of helicity in the isotropic turbulence. To do those work, we look for some quantities like helicity, enstrophy, acceleration and its flatness. And also correlations among them are sought.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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• pp.586-591
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• 1996

Through the analysis of many experimental post-dryout data, it is shown that the most probable flow regime near dryout or quench front is not annular flow but churn-turbulent flow when the mass flux is low. A correlation describing the initial droplet size just after the CHF position at low mass flux is suggested through regression analysis. In the post-dryout region at low pressure and low flow, it is found that the suggested one-dimensional mechanistic model is not applicable when the vapor superficial velocity is very low, i.e., when the flow is bubbly or slug flow regime. This is explained by the change of main entrainment mechanism with the change of flow regime. Therefore, the suggested correlation is valid only in the churn-turbulent flow regime ( $j_{g}$ $^{*}$＝0.5~4.5).).

• International Journal of Aeronautical and Space Sciences
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• 제16권4호
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• pp.510-519
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• 2015

Concerning the issue of high-dimensions, hybrid uncertainties of randomness and intervals including implicit and highly nonlinear limit state function, reliability analysis based on the hybrid uncertainty reliability mode combining with back propagation neural network (HU-BP neural network) is proposed in this paper. Random variables and interval variables are as input layer of the neural network, after the training and approximation of the neural network, the response variables are obtained through the output layer. Reliability index is calculated by solving the optimization model of the most probable point (MPP) searching in the limit state band. Two numerical cases are used to demonstrate the method proposed in this paper, and finally the method is employed to solving an engineering problem of the aerospace friction plate. For this high nonlinear, small failure probability problem with interval variables, this method could achieve a good analysis result.

• Bulletin of the Korean Chemical Society
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• 제15권5호
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• pp.394-399
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• 1994

The catalytic mechanism of malonyl-CoA synthetase from Rhizobium trifolii was investigated by the steady state kinetics and intermediate identification. Initial velocity studies and the product inhibition studies with AMP and PPi strongly suggested ordered Bi Uni Uni Bi Ping-Pong Ter Ter system as the most probable steady state kinetic mechanism of malonyl-CoA synthetase. Michaelis constants were $0.17{\pm}0.04 {\mu}M,\;0.24{\pm}0.18 {\mu}M\;and\;0.045{\pm}0.26 {\mu}$M for ATP, malonate and CoA, respectively. The TLC analysis of the $^{32}P-labelled$ products in reaction mixture containing $[{\gamma}-^{32}P]$ ATP in the absence of CoA showed that PPi was produced after the sequential addition of ATP and malonate. Formation of malonyl-AMP, suggested as an intermediate in the kinetically deduced mechanism, was confirmed by the analysis of $^{31}P-NMR$ spectra of AMP product isolated from the $^{18}O$ transfer experiment using $[^{18}O]$malonate. Two resonances were observed, corresponding to AMP labelled with zero and one atom of $^{18}O$, indicating that one atom of $^{18}O$ transferred from $[^{18}O]$malonate to AMP through the formation of malonyl-AMP. Formation of malonyl-AMP was also confirmed through the TLC analysis of reaction mixture containing $[{\alpha}-^{32}P]$ATP. These results strongly support the ordered Bi Uni Uni Bi Ping-Pong Ter Ter mechanism deduced from the initial velocity and product inhibition studies.