• Progress in Superconductivity and Cryogenics
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• v.16 no.2
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• pp.36-41
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• 2014

Temperature dependence of magnetic moment (m-T) and the magnetization (M-H) at 5 K and 20 K of the in situ processed $MgB_2$ bulk pellets with/without carbon (C) doping were examined. The superconducting critical temperature ($T_c$), the superconducting transition width (${\delta}T$) and the critical current density ($J_c$) were estimated for ten test samples taken from the $MgB_2$ bulk pellets. The reliable m-T characteristics associated with the uniform $MgB_2$ formation were obtained for both $MgB_2$ pellets. The $T_cs$ and ${\delta}Ts$ of all test samples of the undoped $MgB_2$ were the same each other as 37.5 K and 1.5 K, respectively. The $T_cs$ and ${\delta}Ts$ of the C-doped $MgB_2$ were 36.5 K and 2.5 K, respectively. Unlike the m-T characteristics, there existed the difference among the M-H curves of the test samples, which might be caused by the microstructure variation. In spite of the slight $T_c$ decrease, the C doping was effective in enhancing the $J_c$ at 5 K.

• Journal of Veterinary Clinics
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• v.32 no.2
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• pp.215-217
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• 2015

There was no study on the prevalence of doping control of racehorses in Korea. The purpose of this study was to determine prohibited substances in horse races of a drugs testing program. Blood samples were taken from those 298,543 starters prior to racing and the that finished top 3 runners of each race and horses designated by the stewards shall be taken for collection of 91,482 urine samples for the purpose of post-race doping test in Seoul, Busan and Jeju Race Park between 2002 and 2013. Detection and measurement of prohibited substances were carried out by ELISA, GC/MS and LC/MS using standard methods at the Doping Control Center, Korea Racing Authority. Total 0.0030% of pre-races and total 0.0186% of post-races tested positive for prohibited substances. In pre- and post-race, caffeine and ketoprofen were the most detected prohibited substance respectively. We thought that characteristics of pharmacokinetics and pharmacodynamics of drugs resulted in different between plasma and urine. These substances have also been detected with other prohibited drugs suggesting that unintentional feeding or bedding may be the reason and groomers' confusion of candidate horses based by the stewards' research.

• Mass Spectrometry Letters
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• v.13 no.4
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• pp.158-165
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• 2022

Many therapeutic class drugs such as beta-blocker, corticosteroids, NSAIDs, etc are prohibited substances in the horse racing industry. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology makes it possible to isolate drugs from interference, enables various drug analyses in complex biological samples due to its sensitive sensitivity, and has been successfully applied to doping control. In this paper, we describe a rapid and sensitive method based on solid-phase extraction (SPE) using solid phase cartridge and LC-MS/MS to screen for different class's 35 drug targets in equine plasma. Plasma samples were pretreated by SPE with the NEXUS cartridge consisted non-polar carbon resin and minimum buffer solvent. Chromatographic separation of the analytes was performed on ACQUITY HSS C18 column (2.1 × 150 mm, 1.8 ㎛). The elution gradient was conducted with 5 mM ammonium formate (pH 3.0) in distilled water and 0.1% formic acid in acetonitrile at a flow rate of 0.25 mL/min. The selected reaction monitoring (SRM) mode was used for drug screening with multiple transitions in the positive ionization mode. The specificity, limit of detection, recovery, and stability was evaluated for validation. The method was found to be sensitive and reproducible for drug screening. The method was applied to plasma sample analysis for the proficiency test from the Association of Racing Chemist.

• Journal of Food Hygiene and Safety
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• v.5 no.3
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• pp.159-164
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• 1990

To detect and quantitation residual antibiotics and antibacterial agents in meats, we performed a biological assay employing the three microorganisms Bacillus subtilis ATCC 6633, Micrococcus luteus ATCC 9341, and Bacillus cereus var. mycoides ATCC 11778 for the screening purpose and developed a Gas Chromatography-mass Spectrometry(GC/MS) analysis for the confirmation and quantiation. In the biological assay (paper disk method), three test solution are used depending on the character of the residual antibiotics and antibacterial agents, follow by a simple clean up procedure which includes homogenization with Mcilvaine buffer, defatting with includes homogenization with Mcilvaine buffer, defatting with hexane, extraction with chloroform, clean-up by Sep-Pak $C_{18}$ and Bakerbond SPE carboxylic acid column. The chloroform layer is used for the analysis of sulfa agents. macrolides antibiotics and antibacterial agents, Adsorbed materials in the Sep-Pak $C_{18}$ were also employed for th analysis of penicillins and tetracyclines. Effluents from the Sep-Pak $C_{18}$ were cleaned-up one more by Bakerbond 10 SPE COOH column and employed for the analysis of aminoglycosides. In the instrumental analysis by using the GC/MSD, residual antibiotics and antibacterial agent were quantitated by selected ion monitoring (SIM) mode after derivatization. A simultaneous analysis of six residual antibiotic and antibacterial agent such as oxytetracycline, penicillin, ampicillin, choliraphenicol and thiamphenicol was developed with simple cleanup procedures revealing good recovery and reproducibility. Also, simultaneous detection of macrolides antibiotics such as erythromycin, spiramycin, and oleandomycin was developed after acid hydrolysis due to their large molecular structures. Because of the high reproducibility and selectivity of these two methods, it is very desirable that the combination of the two methods be used in the bioassay for the screening of residual antibiotics and antibacterial agent and that GC/MSD analysis be used for the confirmation and quantitation.

• Journal of the Korean Applied Science and Technology
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• v.29 no.3
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• pp.466-472
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• 2012

Visible-light-responding photocatalysts, $N-TiO_2$, were prepared by nitrogen doping onto $TiO_2$. The crystalline structure and morphology, doping state of the prepared photocatalysts were characterized by XRD, FE-SEM, and XPS. The activity of the prepared photocatalysts was examined by the decomposition of methyleneblue. The prepared catalysts were anatase type and the crystallinity was increased with pH. The particle sizes of the prepared catalysts were 5.42, 5.99, 7.58 nm at pH 2.2, 4.7, 9.0, respectively. The particle sizes of the prepared catalysts were slightly increased with pH. The activity of the photocatalysts was directly proportional to the crystallinity of the catalysts. $N-TiO_2$ prepared by nitrogen doping onto $TiO_2$ showed activity under visible light. The doped nitrogen was located not in the lattice but on the surface.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.207-210
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• 2014

$TiO_2$ oxide semiconductor is being widely studied in various applications such as photocatalyst and photosensor. Pd/$TiO_2$ gas sensor is mainly used to detect $H_2$, CO and ethanol. This study focus on increasing hydrogen detection ability of Pd/$TiO_2$ in room temperature through Al-doping. Pd/$TiO_2$ was fabricated by the hydrothermal method. Contacting to Aluminum (Al) foil led to Al doping effect in Pd/$TiO_2$ by thermal diffusion and enhanced hydrogen sensing response. $TiO_2$ nanoparticles were sized at ~30 nm of diameter from scanning electron microscope (SEM) and maintained anatase crystal structure after Al doping from X-ray diffraction analysis. Presence of Al in $TiO_2$ was confirmed by X-ray photoelectron spectroscopy at 73 eV. SEM-energy dispersive spectroscopy measurement also confirmed 2 wt% Al in Pd/$TiO_2$ bulk. The gas sensing test was performed with $O_2$, $N_2$ and $H_2$ gas ambient. Pd/Al-doped $TiO_2$ did not response $O_2$ and $N_2$ gas in vacuum except $H_2$. Finally, the normalized resistance ratio ($R_{H2on}/R_{H2off}$) of Pd/Al-doped $TiO_2$ increases about 80% compared to Pd/$TiO_2$.

• Journal of the Korean Chemical Society
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• v.41 no.8
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• pp.406-413
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• 1997

The endogenous steroids from human urine were simultaneously analyzed by selected ion monitoring method of GC/MS which is currently used for the doping procedure, together with anabolic steroids. The recovery range of this method was 72.33 %∼94.54% and the RSD values of precision and accuracy test were 1.43%∼10.86%, 0.96%∼9.98%, respectively. Using this method steroids profile was investigated in the urine of male volunteers after oral administration of nine anabolic steroids banned by IOC (International Olympic Committee). Urinary endogenous steroids level was varied specifically according to the excretion tendency of the metabolites of anabolic steroids.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1388-1390
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• 2007

This paper investigates how various concentrations of lithium ion influence on crystallization of MgO in thin films formed by spin coating and an the discharge characteristic in a flat fluorescent lamp structure. The XRD results indicate $Li^+$ ion enhances the growth of MgO crystal in a spin coated thin film. The discharge property with the $Li^+$ ion doped MgO films show the lithium ion in MgO film clearly reduce the initial discharge voltages of test devices. Interestingly, the test panels with various doped MgO film have somewhat higher static memory margin of than that of pure-MgO owing probably to the pore structure of spin coated MgO films. The CL spectra, which confirm that the doping creates defects energy levels in the band gap of MgO, show the $F^+$ center is the main defects in doped MgO films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.110-111
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• 2006

In this paper, we investigated resistance characteristic of chalcogenide material for next generation ReRAM nonvolatile memory device with laser irradiation. A AES is used to test Ag doping ratio into a As-Ge-Se-S thin film. A sample resistance was observed in real time with He-Ne laser(632.8nm). As a result, resistance of thermal treated As-Ge-Se-S thin film was $500{\Omega}$ which is smaller than initial $1.3M{\Omega}$. A resistance of non-treated Ag/As-Ge-Se-S thin film was $200{\Omega}$ which is lower than $35M{\Omega}$.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.216-219
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• 2007

Effects of aging treatment of doped-MgO electron emission layer on luminance efficiency of ac-PDP were investigated in this study. Morphological and luminance efficiency with aging treatment were examined, especially with emphasis on the effects of doping elements. The results indicate that the luminance efficiency of test panels depends on the type of doping elements used for MgO and that may be due to the redeposition of MgO during glow discharge.