• 조명전기설비학회논문지
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• 제23권6호
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• pp.109-117
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• 2009

본 논문에서는 영구자석형 릴럭턴스 동기 발전기(PMA-RSG : Permanent magnet assisted-synchronous reluctance motor)에 대한 등가 자기 회로를 사용한 해석모델에 대해서 제시하고, 영구자석형 릴럭턴스 동기 발전기의 외형과 고정자 권선 그리고 특성을 결정하기 위해서 영구자석형 릴럭턴스 통기 발전기의 집중변수 모델(LPM : Lumped parameter model)을 제안한다. 집중변수 모델을 통하여 제안된 기기의 회전자 브리지에서 발생되는 자기 포화 현상에 대해서 예측하고, 기기의 성능에 대해서 효과적으로 검토한다. 집중변수 모델은 유한 요소법(FEM : Finite element method)에 비하여 정확하지는 않지만 영구자석형 릴럭턴스 동기 발전기의 자기적인 특성을 분석하는데 있어서 많은 시간이 걸리지 않으며, 초기 회전기기의 시제품 제작과 최적 설계에 있어서도 많은 장점을 가지고 있다. 집중변수 모델과 유한요소법을 통하여 영구자석형 릴럭턴스 동기발전기폭 초기 설계하고, 실제작을 고려하여 기기를 최적화하여 유한 요소법을 이용하여 설계 검증을 한다. 집중변수 모델의 선형 비선형 모델을 위해서 Matlab을 이용하였다. 제안된 영구자석형 릴럭턴스 통기발전기의 정당성을 검증하기 위해서 실제 역기전력 파형을 측정하였다.

• Bulletin of the Korean Chemical Society
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• 제7권2호
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• pp.137-142
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• 1986

The luminescence spectra of $Ru(bpy)_3^{2+}$ in poly(methacrylic acid) (PMA) solutions varied sensitively with pH. At pH < 5.5, the emission intensity increased with pH up to 4 times, while it decreased with pH beyond the pH. The enhanced emission intensity was accompanied by blue-shift of the emission maxima as much as 15 nm. The enhancement of emission intensity was attributed to the restricted rotational mobility of ligand of the cation bound to densely coiled PMA molecules at pH < 5.5. The sharp decrease in emission intensity with increasing pH near pH 5.6 was accounted for conformational transition of the polymer to more extended structure, which was also revealed in viscosity measurement. The enhancement of emission intensity became higher as NaCl concentration of the solution increased. The binding constant of $Ru(bpy)_3^{2+}$ with two carboxylate groups of PMA was calculated as $2{\times}10^5\;M^{-1}$ in 0.1 M NaCl at pH 5.2. The pH dependence of luminescence quenching rate of $Ru(bpy)_3^{2+}$ by $Cu^{++}$ also showed maximum near pH 5, and the rate was more than $10^3$ times higher than that in water, whereas the maximum enhancement of quenching rate (about 20 times) in poly(acrylic acid) (PAA) solution occurred at pH 4.5. On the other hand, the pH dependence for neutral water soluble nitrobenzene (NB) exhibited opposite trend to that of $Cu^{++}$. The quenching constant vs pH curve for $MV^{++}$ was composite of those for $Cu^{++}$ and NB. The anomalous high quenching rate for $Cu^{++}$ in PMA solution at pH < 5.5 was attributed to the binding of $Ru(bpy)_3^{2+}$ and $Cu^{++}$ to the same region of PMA, when it conforms densely coiled structure in the pH range. The observation of mininium quenching rate for NB near pH 5.5 indicated that the $Ru(bpy)_3^{2+}$ bound to the densely coiled PMA is not accessible by NB, which is in bulk water phase. The composite nature of the pH dependence of quenching rate for $MV^{++}$ in PMA solution was attributed to the smaller binding affinity of the cation to PMA, compared to that of $Cu^{++}$. The sharp, cooperative conformational transition with pH observed in PMA was not revealed in PAA. But, the pH dependence of quenching rates in this polymer reflected increased charge density and, thus, binding of cations to the polymer, and expansion of the polymer chain with pH.

• Tuberculosis and Respiratory Diseases
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• 제70권3호
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• pp.218-223
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• 2011

Background: We investigated whether curcumin and genistein affect the MUC5AC mucin production from human airway epithelial cells that is induced by phorbol 12-myristate 13-acetate (PMA) or tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$). Methods: Confluent NCI-H292 cells were pretreated with each agent for 30 min and then stimulated with PMA or TNF-${\alpha}$ for 24 hours. MUC5AC mucin production was measured by an ELISA. Results: (1) Curcumin dose-dependently inhibited the production of MUC5AC mucin that was induced by PMA or TNF-${\alpha}$; (2) Genistein inhibited PMA-induced MUC5AC mucin production. However, it did not decrease TNF-${\alpha}$-induced MUC5AC mucin production. Conclusion: These results suggest that curcumin and genistein inhibit the production of airway mucin induced by PMA.

• Molecules and Cells
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• 제23권2호
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• pp.138-144
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• 2007

Previously we showed that the human GM3 synthase gene was expressed during the induction of megakaryocytic differentiation in human leukemia K562 cells by phorbol 12-myristate 13-acetate (PMA). In this study we found that treatment of PMA-induced K562 cells with $G{\ddot{o}}6976$, a specific inhibitor of PKC, and U0126, an inhibitor of the extracellular signal-regulated kinase (ERK) reduced expression of GM3 synthase, whereas wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K) did not. Moreover, activation of ERK and cAMP response element binding protein (CREB) was prevented by pretreatment with $G{\ddot{o}}6976$ and U0126. PMA stimulated the promoter activity of the 5'-flanking region from -177 to -83 region of the GM3 synthase gene, and mutation or deletion of a CREB site located around -143 of the promoter reduced PMA-stimulated promoter activity, as did the inhibitors $G{\ddot{o}}6976$ and U0126. Our results demonstrate that induction of GM3 synthase during megakaryocytic differentiation in PMA-stimulated human leukemia K562 cells depends upon the PKC/ERK/CREB pathway.

• 농업과학연구
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• 제49권4호
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• pp.795-807
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• 2022

The development and commercialization of industrial genetically modified (GM) organisms is actively progressing worldwide, highlighting an increased need for improved safety management protocols. We sought to establish an environmental monitoring method, using real-time polymerase chain reaction (PCR) and propidium monoazide (PMA) treatment to develop a quantitative detection protocol for living GM microorganisms. We developed a duplex TaqMan quantitative PCR (qPCR) assay to simultaneously detect the selectable antibiotic gene, ampicillin (AmpR), and the single-copy Escherichia coli taxon-specific gene, D-1-deoxyxylulose 5-phosphate synthase (dxs), using a direct cell suspension culture. We identified viable engineered E. coli cells by performing qPCR on PMA-treated cells. The theoretical cell density (true copy numbers) calculated from mean quantification cycle (Cq) values of PMA-qPCR showed a bias of 7.71% from the colony-forming unit (CFU), which was within ±25% of the acceptance criteria of the European Network of GMO Laboratories (ENGL). PMA-qPCR to detect AmpR and dxs was highly sensitive and was able to detect target genes from a 10,000-fold (10^-4) diluted cell suspension, with a limit of detection at 95% confidence (LOD_95%) of 134 viable E. coli cells. Compared to DNA-based qPCR methods, the cell suspension direct PMA-qPCR analysis provides reliable results and is a quick and accurate method to monitor living GM E. coli cells that can potentially be released into the environment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.836-837
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• 2011

본 논문에서는 PMa-SynRM과 IPMSM의 출력 및 손실 특성 비교분석을 수행하였다. 비교분석을 위한 모델을 선정하여 모델별 유한요소법해석을 통해 성능 및 손실특성 해석을 수행하고, 제어정수 추출을 통해 출력특성곡선을 유도하여 전동기의 각 운전영역에서의 특징을 비교분석한다.

• Bulletin of the Korean Chemical Society
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• 제29권7호
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• pp.1320-1322
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• 2008

Phosphomolybdic acid supported on silica gel (PMA-$SiO_2$) is an efficient catalyst for the activation of TMSCN for the facile cyanosilylation of various aldehydes. Cyano transfer from TMSCN to aldehyde proceeds smoothly at rt in presence of 0.8 mol % of PMA-$SiO_2$ leading to a range of cyanosilylether in excellent yield (mostly over 93%) within short reaction time (30 min). The catalyst can be recovered and reused several times without loss of activity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.103-105
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• 2009

This paper presents the maximum-power control simulation for PMA-SynRM. For maximum power, the maximum torque / current control method is conducted in constant-torque range and flux-weakening control method is conducted in constant-power range. For considering the nonlinear characteristics of inductance, machine constant is determined by FEM. Finally, experiment is conducted to calculate the efficiency.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2261-2266
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• 2007

In this study, the numerical analysis to estimate condensation heat and mass transfer of the condenser was carried out using the PMA (porous medium approach). In the PMA, the details of tube bundle in the condenser are replaced by the porous medium, and the flow resistance term is added in the momentum equation. In this regard, the PMA is quite helpful for the study of tube bundle in the large condenser. The pressure loss through tube bundle can be compensated by viscous and inertial momentum sink terms, which was validated numerically. Value of the pressure drop was compared to that of Butterworth correlation. Three dimensional analysis of condensation for McAllister condenser with the PMA was conducted using Fluent 6.2 and UDFs (use-defined functions). The result of condensation rate was analogous to previous results (experimental and numerical data).

• Journal of Electrical Engineering and Technology
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• 제1권1호
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• pp.92-97
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• 2006

This paper presents the characteristic analysis and the optimal design of a permanent magnetic actuator (PMA) for a vacuum circuit breaker (VCB) using a two-dimensional finite element analysis. The purpose of this research about a PMA is to minimize the breaking time and the volume of the permanent magnet within the limits of the holding force and maximum current in the coil. The conjugate gradient method is used as an optimization algorithm. The node moving technique is iteratively implemented until the design variables of the PMA are optimized. In this paper, the optimal design of a PMA is accomplished to improve the conventional design methods.