• International Journal of Railway
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• v.3 no.1
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• pp.14-18
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• 2010

This paper describes design and characteristic analysis of long primary type linear synchronous motor (LSM) for high speed train system. LSM is designed using loading distribution method and magnetic equivalent circuit. For characteristic analysis of LSM, analytical and numerical methods are applied. Analytical method for solving the magnetic field distribution of the analytic model is based on the Maxwell’s equations. Using the characteristic equation and magnetic equivalent circuit, we analyze the effect of variation of parameters, and then we validate the result by comparing with numerical method by finite element method (FEM). We compare the analytical method with numerical method for analyzing the effect by variable parameters. This result will be useful of design and forecast of performance without FEM.

• Journal of Magnetics
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• v.18 no.3
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• pp.361-364
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• 2013

Permanent magnet flux switching motor (PMFSM) is a novel double salient machine which employs PMs instead of field winding for excitation. PMFSM contains only one set of armature winding, thereby features simple control strategy, low cost power inverter and substantial high efficiency. Due to the unique double salient structure and operation principle, the generated cogging torque in PMFSM is critical and quite different compared to the traditional PM machines. This paper presents and investigates various design techniques for reducing cogging torque in PMFSM. Firstly, an analytical model is proposed to study the influence of different methods on cogging torque. Then the optimal design parameters for minimizing cogging torque are determined by the analytical model, which significantly reduces the computational efforts. At last, the cogging torque with different design approaches are simulated by FEA along with the average output electromagnetic torque, which validates the analysis above.

• Computers and Concrete
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• v.24 no.2
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• pp.117-123
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• 2019

Optimization is an important subject which is widely used in engineering problems. In this paper, an analytical method is developed for optimum design of reinforced concrete beams considering both flexural and shear effects. A closed-form formulation is derived for optimal height and rebar of beams. The total material cost of steel and concrete is considered as the objective function which is minimized during the optimization process. The ultimate flexural and shear capacities of the beam are considered as the main constraints. The ultimate limit state is considered for deriving the relations for flexural capacity of the beam. The design requirements are considered according to the item 9 of the Iranian National Building. Analytical formulas and some curves are proposed to be used for optimum design of RC beams. The proposed method can be used to perform the optimization of RC beams without the need of any prior knowledge in optimization. Also, the results of the studied numerical example show that the proposed method results in a better design comparing with the other methods.

• BMB Reports
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• v.55 no.9
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• pp.413-416
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• 2022

Ferroptosis is a type of programmed cell death distinct from apoptosis or necroptosis. Ferroptosis is well characterized by an iron-dependent accumulation of lipid peroxides and disruption of cellular membrane integrity. Many metabolic alterations can prevent or accelerate ferroptosis induction. Recent advances in analytical techniques of mass spectrometry have allowed high-throughput analysis of metabolites known to be critical for understanding ferroptosis regulatory metabolism. In this review, we introduce mass spectrometry-based analytical methods contributing to recent discovery of various metabolic pathways regulating ferroptosis, focusing on cysteine metabolism, antioxidant metabolism, and poly-unsaturated fatty acid metabolism.

• Analytical Science and Technology
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• v.36 no.5
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• pp.250-257
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• 2023

The development of a spectrofluorimetric method for the determination of trimethoprim according to the reaction between O-phthalaldehyde (OPA) in highly alkaline media, and 2-mercaptoethanol (2ME) and this reaction gives fluorescent product measured at (458) nm when excited at (342) nm. The optimization of the analytical parameters that influence intensity was investigated. The intensity of fluorescence of the formed product was linearly related to the concentration of trimethoprim in the (100-1200) ng mL^-1 range. The limit of detection and limit of quantification were estimated to be (22.54) ng mL^-1 and (75.15) ng mL^-1 respectively. The utility of the proposed methods was successfully verified by analysis of trimethoprim in pure and real pharmaceutical preparations with high accuracy, the recovery percentages Re%, were found to be (100.5) % and (99.76) % for pure drug and pharmaceutical preparations respectively.

• Analytical Science and Technology
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• v.18 no.2
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• pp.163-167
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• 2005

In this study, a novel analytical method has been developed for the rapid determination of L-carnitine in human plasma using electrospray ionization tandem mass spectrometry. Free carnitine (FC) was analyzed after extraction with 80% methanol and total carnitine (TC) was analyzed after hydrolysis and extraction. Acyl carnitine (AC) was subtracted FC from TC. Analytical methods used multiple reaction monitoring (MRM) scan modes. A correlation coefficient of linear regression ($r^2$) was 0.9995, recovery was 97%, reproducibility was less than 10%, and limit of detection (LOD) was $0.0016{\mu}mol/L$. This method reduced sample preparation time and showed high resolution and good reproducibility compared to that with liquid chromatographic methods. Normal control showed AC was lower than FC. Clinical management of patients with inborn error of metabolism showed FC was lower than AC. Thus, carnitine fraction level was very important to monitoring patients with metabolic disorder.

• Analytical Science and Technology
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• v.22 no.5
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• pp.422-431
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• 2009

The analytical results of wear metals such as Na, Mg, Al, Si, P, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, Ba, Pb in oil samples are compared by portable and bench-top XRF methods as a basic study for the development of portable X-ray fluorescence spectrometer. The instrumental parameters such as measurement time of portable and bench-top XRF were optimized using certified reference materials of hydrocarbon oil with 20 wear metals in concentration range from 10 to 900 mg/kg. The analytical results of 20 wear metals in certified reference materials and new/used engine oil samples were compared by empirical and fundamental parameter methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.12
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• pp.1-5
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• 1972

In order to compare the analytical efficiency of the Kjeldahal, Dye binding and Biurett method for the determination of nitrogen content in the brown rice, correlation coefficients were calculate with the analytical data obtained by the above mentioned 3 different methods for the brown rice of 36 varieties or lines grown at 5 different nitrogen levels (0, 7.5, 15.0, 22.5 and 30.0kg/10a). Analysis of variance were made for the data of 6 varieties among those 36, and compared the precision of the data obtained by the 3 analytical methods. The expenditure (in terms of chemicals and labour) required for the 3 methods are also compared. The results are summarized as follows; 1. The correlation between D. B. C. and Kjeldahl value were generally more significant than the correlation between the value of Biurett and the value of Kjeldahl. But, the D. B. C. method generally overestimates than the Kjeldahl method at both extreme low and extreme high nitrogen contents, and the Biurett method includes more dispersed error than other two methods, though the optical values are parallel to the Kjeldahl nitrogen values at any levels of nitrogen applied. 2. The varietal difference in nitrogen value obtained by the 3 methods were different at the different nitrogen level applied. That is the interaction between variety and analytical method, and between the nitrogen level and analytical method were significant statistically. 3. The coefficient of variance (C, V.) was largest in the data analyzed by Biurett method and next in the data analayred by D. B. C. method. In the data analyzed by Biurett, the C. V. increased along onglong increase of nitrogen applied. But, in the data obtained by D. B. C. or Biurett the C. V. increased along the decrease of nitrogen applied. 4. From the comparison of the expenditure (in terms of chemicals and labour) required for the analysis of 100 samples by 3 methods, it was noticed that, the Biurett or D. B. C. method largely curtail the chemical expenditure and labour costs. Especially the Biurett method could curtail more labour costs.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.62-65
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• 2008

• 한국가스학회:학술대회논문집
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• 2002.05a
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• pp.59-66
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• 2002