• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.5
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• pp.115-121
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• 2014

The intrinsic simplicity, ruggedness, and simple power electronic drive requirement of a Switched Reluctance Motor(SRM) make it possible to use in many commercial adjustable speed application. The simple magnetic circuit results in a high efficiency drive and low temperature rise, and the drive system provides a good drive characteristics. This paper is provides two phase 4/3 SRM that is similar to two phase 6/3 SRM as aspect to magnetic structure. Although 6/3 SRM does not experience any flux reversal as the flux is in the same direction whether phase A or B is excited, but two phase 4/3 SRM experiences a flux reversal in small part of stator yoke. The flux reversal in two phase 4/3 SRM could be relieved by an adjustment of stator yoke structure. The magnetic analysis and design considerations of the two phase 4/3 SRM have been obtained by the finite element method analysis (FEM).

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2194-2200
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• 2014

This paper presents a design of novel 2-phase 6/5 switched reluctance motor (SRM) for an air-blower application. This type of motor is suitable for the applications that require high speed and only one directional rotation as air-blower. The desired air-blower is unidirectional application, and requires a wide positive torque region without torque dead-zone. In order to get a wide positive torque region without torque dead-zone during phase commutation, asymmetric inductance characteristic with non-uniform air-gap is considered. The proposed motor can be operated at any rotor position. The proposed 6/5 SRM uses short flux path technique that achieved by means of winding configuration and lamination geometry. The purpose of short flux path is to reduce the core loss and the absorption MMF in the stator. The proposed 2-phase 6/5 SRM is verified by finite element method (FEM) analysis and Matlab-Simulink. In order to verify the design, a prototype of the proposed motor was manufactured for practical system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.5
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• pp.92-97
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• 2014

The SRM is a doubly salient, singly excited machine. The torque is developed by the tendency for the magnetic circuit to adopt a configuration of minimum reluctance, i.e. for the rotor to move into in line with the stator poles and to maximize the inductance of the coils excited. It is common practice to combine them into groups of poles which are excited simultaneously; for example, 8/6 SRM (8 stator poles and 6 rotor poles) for 4 phases, 6/4, 12/8 SRM for 3 phases, 4/2, 6/3 SRM for 2 phases. Small number of phases in two-phase SRMs allows more cost savings with regards to the switching devices in the converter. The stator back irons of two phase 6/3 SRM and C-core 4/3 SRM does not experience any flux reversal as the flux is in the same direction whether phase A or B is excited. In this study, the similarities, the differences, and structural characteristics between the two SRMs was studied, The magnetic analysis also has been carried out by the finite element method analysis (FEM).

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.673-675
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• 2015

This paper presents a design of a high speed 2-phase 6/5 switched reluctance motor (SRM) for an air-blower application. This type of motor is suitable for the applications that require high speed and only one directional rotation as air-blower. The desired air-blower is unidirectional application, and requires a wide positive torque region without torque dead-zone. In order to get a wide positive torque region without torque dead-zone during phase commutation, asymmetric inductance characteristic with non-uniform air-gap is considered. The proposed motor can be operated at any rotor position. The proposed 6/5 SRM uses short flux path technique that achieved by means of winding configuration and lamination geometry. The purpose of short flux path is to reduce the core loss and the absorption MMF in the stator. The proposed 2-phase 6/5 SRM is verified by finite element method (FEM) analysis and Matlab-Simulink. In order to verify the design, a prototype of the proposed motor was manufactured for practical system.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.38-45
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• 2012

A novel kind of switched reluctance motor (SRM) with short flux path is proposed in this paper. Phase excitation in the SRM gives short flux paths, hence reducing the magnetomotive force required to drive the machine, resulting in significant reduction of copper wire and core losses compared to the typical SRM with diametric circulation of magnetic flux. To verify the performance, the characteristics analysis of a double-stator SRM, a 6/5 SRM with C-core structure, and a 4/5 two-phase SRM, which all have short flux paths, and a comparison with conventional SR motors are executed. The comparison demonstrates that the proposed motor offers some advantages in terms of torque and efficiency.

• YAKHAK HOEJI
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• v.48 no.3
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• pp.207-212
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• 2004

An analytic method was developed for the quantitation of $\Delta$$^{9}-$ tetrahydrocannabinol (THC) and 11-nor-9-carboxy THC (THC-COOH) in human hair. After hair samples were pulverized using Freezer Mill, deuterated internal standards were added and digested in 1 N NaOH at $100^{\circ}C$ water bath for 30 min. Digest solutions were extracted by 5 ml hexane：ethyl acetate (90：10) after acidification with acetic acid. The organic phase was evaporated under N 2 and derivatized by BSTFA (with 1% TMCS) at $85^{\circ}C$ for 45 min. The derivatized solution was separated on HP-5MS column ($30m{\times}0.25mm{\times}0.25mm$) and detected using EI-GC-MS with selective ion monitoring mode. The assay of calibration was ranged from 5 to 100 ng/50 mg hair ($r^2$＞0.99) for THC and THC-COOH. Within and between-run precision were calculated at 6, 30, 60 ng/50 mg hair with coefficients of variation less than 11%. Within and between run accuracies at the same concentrations were$\pm$14% and $\pm$30% of target for both analytes, respectively. Absolute and relative recovery at 10 and 100 ng were 60∼91％. The method was used to detect and quantify THC and THC-COOH in cannabis abuser's hairs (N = 16) and SRM (N=5, THC 1 ng/mg, NIST). We detected THC and THC-COOH in only one hair sample. In SRM, % accuracy was 93% (range 86∼103%) and precision (% CV) was 8.14. We began to set up a quantitative analysis of THC and THC-COOH using EI-GC-MS. Continuously, we need to modify and develop this method in order to apply for identification in cannanbis users' hair.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1976-1980
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• 2010

A simple and reliable method has been developed to selectively separate and concentrate trace amounts of Fe(III) ions from water and food samples by using flame atomic absorption spectrometry. A new reagent, 5-hydroxy-4-ethyl-5,6-di-pyridin-2-yl-4,5-dihydro-2H-[1,2,4] triazine-3-thione, was synthesized and characterized by using FT-IR spectroscopy and elemental analysis. Effects of pH, concentration and volume of elution solution, sample flow rate, sample volume and interfering ions on the recovery of Fe(III) were investigated. The optimum pH was found to be 5. Eluent for quantitative elution was 10 mL of 2 M HCl. The preconcentration factor of the method, detection limit (3s/b, ${\mu}gL^{-1}$) and relative standard deviation values were found to be 25, 4.59 and 1%, respectively. In order to verify the accuracy of the method, two certified reference materials (TMDA 54.4 lake water and SRM 1568a rice flour) were analyzed. The results obtained were in good agreement with the certified values. The method was successfully applied to the determination of Fe(III) ions in water and food samples.

• Journal of Environmental Health Sciences
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• v.35 no.4
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• pp.322-333
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• 2009

In this study, a measurement method was evaluated for the determination of polycyclic aromatic hydrocarbons (PAHs) in the ambient atmosphere. PAHs were sampled by high-volume samplers, and were then analysed with a GC/MS system. Particulate PAHs were collected on $8"{\times}10"$ quartz fiber filter, while vapor phase PAHs were adsorbed on polyurethane foam (PUF). Target compounds included a total of 36 PAHs, which are known to be frequently detected in the urban atmosphere. It was not necessary to clean-up samples before samples were analyzed using GC/MS, and the overall performance of the method was tested by a variety of quality control and quality assurance schemes. It is generally known that the clean-up procedure can negatively affect the recovery of samples. Precision and accuracy was evaluated using SRM provided by US NIST, and the results were generally satisfactory and reliable. However, the GC/MS method appeared not to be adequate for 6-rings PAHs, such as coronene, due to its lower sensitivity. In addition, collection efficiencies for low molecular compounds, such as 2-rings PAHs, were poor because of the lower retention volume of the PUF adsorbent. As a result, it was concluded that the method based on high-volume sampling and GC/MS analysis can give very reliable data by simultaneous sampling of both particulate and vapor phases for 3-rings to 5-rings PAHs of environmental concern.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.418-424
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• 2015

The content of ${\beta}$-carotene in agricultural foods, such as seasonings, tea, vegetables, cereals, nuts & seeds, oils & fats, and fruits, were quantitatively analyzed using reversed-phase HPLC with an UV/visible detector. Standard reference material (SRM) 2385 was used as a control material to validate measurement of ${\beta}$-carotene in this study. Recovery percentage and relative standard deviation of ${\beta}$-carotene in SRM 2385 were 102% and 1.73%, respectively. Vegetables and tea contained relatively high concentrations of ${\beta}$-carotene (young barley powder, $17,293.95{\mu}g/100g$; raw young barley, $2,755.15{\mu}g/100g$; dried green tea leaves, $13,671.85{\mu}g/100g$; green tea powder, $7,579.04{\mu}g/100g$). Contents of ${\beta}$-carotene in nuts & seeds as well as oils & fats ranged from $11.32{\mu}g/100g$ in almond products (roasted with salt) to $58.56{\mu}g/100g$ in perilla seed oil. Among 20 fruits, a high content of ${\beta}$-carotene was found in apricots (raw), which contained $2,280.35{\mu}g/100g$.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.89-95
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• 2017

A rapid, sensitive analytical method for glucuronolactone in beverages was developed and validated using hydrophilic interaction liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HILIC-ESI-MS/MS). To determine the optimum analytical conditions for glucuronolactone, three different kinds of HILIC columns and two mobile phases with different pH values were examined. An amide-bonded stationary phase with a pH 9 acetonitrile-rich mobile phase was the best condition in terms of column retention, ESI-MS/MS response area, and signal-to-noise ratio. After extraction, glucuronolactone was separated through the HILIC amide column and detected by negative ESI-MS/MS in selected reaction monitoring (SRM) mode. Nine energy drinks sold in Korea were spiked with glucuronolactone at a concentration of 5 ng/mL; the Monster $Energy^{TM}$ sample showed the smallest peak area and its signal-to-noise ratio was used for method validation. Good linearity was obtained in the concentration range from 20 to 1500 ng/mL with a correlation coefficient > 0.998. The developed method had a limit of detection (LOD) of 6 ng/mL and a limit of quantitation (LOQ) of 20 ng/mL. The recovery of this method at concentration of 20, 100, 500, and 1000 ng/mL was 96.3%-99.2% with relative standard deviations (RSD) of 1.6%-14.0%. A reproducibility precision assessment at concentration of 100 and 500 ng/mL was carried out among three laboratories. The recovery of that evaluation was 95.1%-102.3% with RSD of 2.7%-7.0%. An analysis of variance indicated that there was no difference between the recovery results of the three laboratories at the 5% significance level. The validated method is applicable to inspecting beverages adulterated with glucuronolactone in Korea.