• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.159-162
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• 2000

The purpose of this study is to develope an accurate procedure for measuring the glass content of fly ash produced by bituminous coal to assist in predicting their behavior in concrete. Quantitative mineralogical compositions of fly ashes were obtained by internal standard method using powder X-ray diffraction analysis. In the X-ray diffraction method, the specimen and standard fluorite were cautiously mixed and pulverized to 22$\mu$m in wet process so as to avoid the prefered orientation of the crystal and microabsorption effect of X-ray. calibration curve were fitted for several references peaks of four phases:$\alpha$-quartz. mullite, magnetite, hematite. The amount of glass was calculated by subtracting the amount of crystal phase and loss on ignition from the total amount. Glass content determined with this method ranged from 66.7 to 75.wt%.

• 대한화학회지
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• 제27권6호
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• pp.419-423
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• 1983

음이온세제와 비이온세제의 혼합물에서 alkylbenzene sulfonate 계통의 음이온 세기가 NMR법에 의해서 정량되었다. 음이온세제와 비이온세제의 혼합물에 대한 NMR 스펙트럼에서, 벤젠 그룹은 6.5∼8ppm에서 중첩된 피크를 보여주나 sampling 후의 벤젠 그룹은 7∼8ppm에서 두개의 doublet을 보여준다. 검량선은 음이온세제의 벤젠그룹과 초산의 메칠그룹의 상대적인 면적비에 의해서 작성되었다. (초산은 내부표준물로 사용되었다.)

• 경영과학
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• 제33권1호
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• pp.49-58
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• 2016

Focusing on the drastic increase of smart devices, machine generated data expansion is a general phenomenon in network services and IoT (Internet of Things). Especially, built-in multi sensors in a smart device are used for collection of user status and moving data. Combining the internal sensor data and environmental information, we can determine landmarks that decide a pedestrian's locations. We use an ANOVA method to analyze data acquired from multi sensors and propose a landmark classification algorithm. We expect that the proposed algorithm can achieve higher accuracy of indoor-outdoor positioning system for pedestrians.

• 한국임상약학회지
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• 제10권1호
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• pp.38-41
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• 2000

A high-performance liquid chromatographic method with fluorometric detection was evaluated for analysis of ofloxacin in plasma. Biological fluids (plasma, $200\;{\mu}L$) were prepared for assay by protein precipitation with chlorofurm. The detection of ofloxacin and triamterene as an internal standard were performed at 358 nm for excitation and 495 nm for emission. The HPLC separation was carried out on Ultrasphere ODS column (4.6 mm${\times}25\;cm,\;5\;{\mu} m$) with acetonitrile $(45\%)$-phosphoric acid $(1.5\%)\;containing\;0.3\%$ sodium laurylsulfate as the mobile phase. The flow-rate was 1.0 mL/min. The calibration graphs were linear from 3.0 to 80 ng/mL with r=0.998. The minimal detectable concentration in plasma was 1.5 ng/mL. The proposed technique is reproducible, selective, reliable and sensitive.

• Archives of Pharmacal Research
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• 제19권6호
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• pp.566-569
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• 1996

A sensitivity method has been developed for the detection and determination of niflmic acid(NA) in human urine. Samples were extracted with diethylether. Flunixin (FN) was added to the sample prior to extraction as an internal standard. Niflumic acid was converted to its methyl derivative and analyzed by capillary gas chromatography/negative chemical isonization mass spectrometry. Using selected ion monitoring (SIM), the levels of NA down to 5 pg/ml could be detected in 5 ml spiked urine sample. Calibration curve was linear over the range of 0.5 ppm-50 ppm. The recovery of niflumic acid from urine at 40 pg/ml was to be $91.7{\pm}3.8(n=3)$ and the coefficient of variation was 4.1%.

• 약학회지
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• 제37권4호
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• pp.356-361
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• 1993

A sensitive method for the determination of methamphetamine(MA) and amphetamine(AM) in hair was developed by gas chromatography/mass spectrometry using stable isotope-labeled internal standards, amphetamine-d$_{5}$ and methamphetamine-d$_{5}$. Hair sample was washed with MeOH, incubated with MeOH(I% HCI) overnight at $37^{\circ}C$ while stirring and extracted using solid phase extraction column on a vacuum manifold. The extract obtained was pentafluoropropionated, and applied to GC/MS. The calibration curves of MA and AM were linear from 2.5 to 250 ng (r>0.99 for both). The limit of detection was 0.1 ng/mg in hair and cut-off level was set at 0.25 ng/mg for both. Hair samples of 27 MA abusers showed positive results in the range 0.7 to 106.8 ng/mg. AM, its metabolite, was detected in 20 out of 27 samples. The ratio of MA versus AM was 4.6~38.3 in specimens. Hair analysis for methamphetamine by GC/MS is an effective method for identifying long-term drug abusers.

• 한국군사과학기술학회지
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• 제8권2호
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• pp.49-57
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• 2005

The target localization using the line arrays buried in the seabed is a difficult problem due to the complex sea bottom characteristics and need to compensate the wave propagation effect to localize the target accurately Sound speed mismatch in the seabed causes a bias in the target bearing estimation and induces the localization error. In this paper we describe a target localization method with improved accuracy of target bearing and localization by calibration the sound speed in the seabed. The proposed algorithm is verified through the ocean data.

• Journal of the Optical Society of Korea
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• 제9권3호
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• pp.107-110
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• 2005

An optical method of measuring hematocrit noninvasively is presented. An LED Light with multiple wavelengths was irradiated on fingernail and transmitted light from the finger was measured to predict hematocrit. A finger probe contained an LED array and detector. Our previous experience showed that prediction accuracy was sensitive to reliability of the finger probe hardware and we optimized the finger probe parameters such as the internal color, detector area and the emission area of a light source based on Design of Experiment. Using the optimized finger probe, we developed a hematocrit monitoring system and tested with 549 persons. For the calibration model with 368 persons, a regression coefficient of 0.74 and a standard deviation of 3.67 and the mean percent error of $8\%$ were obtained. Hematocrits for 181 persons were predicted. We achieved a mean percent error of $8.2\%$ where the regression coefficient was 0.68 and the standard deviation was 3.69.

• Bulletin of the Korean Chemical Society
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• 제19권5호
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• pp.524-526
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• 1998

A sensitive and specific method is described for the determination of midazolam in human plasma. The drug was extracted from 1 mL of carbonate buffered plasma (pH 9.6) with 8 mL of diethyl ether. Famprofazone was used as internal standard. The organic phase was evaporated to dryness. The residue was dissolved in methanol for the direct analysis by gas chromatograph-nitrogen phosphorus detector system. In the concentration range of 1-5000 ng/mL, the calibration curve was linear. The coefficients of variation from the precision test were <6% at the range of the concentration of 0.10-2.00 μg/mL and the detection limit for midazolam in 1 mL of plasma was o.5 ng. This assay is more sensitive, selective, simple and rapid than earlier methods. Plasma midazolam concentrations were determined by this method after administration of midazolam.

• Structural Engineering and Mechanics
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• 제71권1호
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• pp.77-87
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• 2019

In this paper, the interaction between two neighboring tunnel has been investigated using PFC2D. For this purpose, firstly calibration of PFC was performed using Brazilian experimental test. Secondly, various configuration of two neighboring tunnel was prepared and tested by biaxial test. The maximum and minimum principle stresses were 0.2 and 30 MPa respectively. The modeling results show that in most cases, the tensile cracks are dominant mode of cracks that occurred in the model. With increasing the diameter of internal circle, number of cracks decreases in rock pillar also number of total cracks decreases in the model. The rock pillar was heavily broken when its width was too small. In fixed quarter size of tunnel, the crack initiation stress decreases with increasing the central tunnel diameter. In fixed central tunnel size, the crack initiation stress decreases with increasing the quarter size of tunnel.