• Analytical Science and Technology
• /
• v.7 no.4
• /
• pp.441-453
• /
• 1994

Two extraction methods, liquid-liquid extraction(LLE) and solid-phase extraction(SPE), coupled with GC/MS were compared as preconcentration procedures for priority pollutants in water. Among the semi-volatile priority pollutants, 11 acid and 44 base/neutral compounds were spiked in reagent water. With LLE, which is a modification of EPA Method 625, the overall mean recovery of the 54 compounds was 91% with a mean relative standard deviation(RSD) of 4.6%. With SPE, the overall mean recovery of the 52 compounds was 53% with a mean RSD of 8.9%. The detection limits of both methods were in the range of $1{\sim}5{\mu}g/l$.

• Advances in nano research
• /
• v.12 no.2
• /
• pp.139-150
• /
• 2022

This paper presents sets of explicit analytical equations that compute the static displacements of nanobeams by adopting the nonlocal elasticity theory of Eringen within the framework of Euler Bernoulli and Timoshenko beam theories. Castigliano's theorem is applied to an equivalent Virtual Local Beam (VLB) made up of linear elastic material to compute the displacements. The first derivative of the complementary energy of the VLB with respect to a virtual point load provides displacements. The displacements of the VLB are assumed equal to those of the nonlocal beam if nonlocal effects are superposed as additional stress resultants on the VLB. The illustrative equations of displacements are relevant to a few types of loadings combined with a few common boundary conditions. Several equations of displacements, thus derived, matched precisely in similar cases with the equations obtained by other analytical methods found in the literature. Furthermore, magnitudes of maximum displacements are also in excellent agreement with those computed by other numerical methods. These validated the superposition of nonlocal effects on the VLB and the accuracy of the derived equations.

• Journal of the Microelectronics and Packaging Society
• /
• v.7 no.4
• /
• pp.17-22
• /
• 2000

In this paper, methods to analyze wire sweep during the semiconductor chip encapsulation have been studied. The wire sweep analysis is used to analyze the deformation of bonding wires that connect the chip to the leadframe during encapsulation. The analysis is done using either analytical solutions or numerical simulation. The analytical solution is used for rough but fast calculation of wire sweep. The results from the numerical simulation are closest to the experimental results.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.03b
• /
• pp.151-158
• /
• 2000

The lateral deformation of one row pile groups was investigated based on analytical study and a numerical analysis. The emphasis was on quantifing the load transfer of pile groups subjected to lateral soil movement. An analytical method to consider pile-soil interaction in weathered soil was developed using load-transfer curve methods. Through the comparative study, it is found that the prediction by present approach is in good agreement with the general trend observed by in-situ measurements.

• Communications for Statistical Applications and Methods
• /
• v.7 no.2
• /
• pp.457-463
• /
• 2000

Recently, statistical analysis tools have been changed to the applications on the World Wide Web that access data stored in databases. On-line analytical processing(OLAP) is a class of technologies that give users statistical information with multidimensional views of data in databases. In this paper, we introduce the concept and requisites of OLAP system, and we propose some research issues.

• Korean Journal of Hydrosciences
• /
• v.1
• /
• pp.1-14
• /
• 1990

The analytical diffusion model is first formulated and its characteristics are critically reviewed. The flood events during the 1985-1986 flood seasons in the IHP Pyungchang Representative Basin are routed by this model and are compared with those routed by the kinematic wave model. The present model is proven to be an excellent means of taking the backwater effects due to lateral inflow or downstream river stage variations into consideration in channel routing of flood flows. It also requires much less effort and computing time at a desired station compared to any other reliable flood routing methods.

• Analytical Science and Technology
• /
• v.9 no.4
• /
• pp.416-419
• /
• 1996

We performed a comparative study of analysis methods of Methemoglobin with a CO-Oximeter and an UV/Vis(SATO's Methd). The correlation coefficient of two method for the MetHb% determinations was estimated to be 0.9575. The concentrations of MetHb on most of the dead burn victims(87%) were shown below 10%. The concentrations of COHb were rang between 15% and 85%.

• Analytical Science and Technology
• /
• v.8 no.4
• /
• pp.1089-1094
• /
• 1995

Methods for the measurement of copper(II) complexing capacity (CuCC) of natural waters by using the back-extraction of bis(benzoyl-trifluoroacetonate)copper(II) and the extraction rate of dithizonato-copper(II) complex were described. Experimental results show that the CuCC of the Kiryu river water samples from urban area were consistently larger than those from up-stream, due to a ligand which originated from human activities.

• Geomechanics and Engineering
• /
• v.3 no.2
• /
• pp.109-116
• /
• 2011

This note presents an analytical solution for the determination of the shape factor of a flush bottom piezometer in a uniform, isotropic, and incompressible deep soil deposit. The deduced shape factor is compared to published values obtained by approximate methods. Depending on the selected value, the difference may reach 11%.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.10 no.1
• /
• pp.126-146
• /
• 2000

To develop and evaluate formaldehyde measurement method using 2,4-dinitro-phenylhydrazine (2,4-DNPH) coated sampler and gas chromatography, laboratory test and field test were conducted. Results of this study are as follows. Limit of detection(LOD) of measurement methods, HPLC-UVD, GC-NPD and GC-FID, is $0.008{\mu}g/m{\ell}$ $0.060{\mu}g/m{\ell}$, $0.472{\mu}g/m{\ell}$ respectively. Coefficiency of measurement methods, HPLC-UVD, GC-NPD and GC-FID, is 0.008, 0.009, 0.020 respectively. Desorption efficiency of sep-pak xposure aldehyde sampler and sorbent sample tube is 1.05(range : 0.99 - 1.12), 1.02(range : 0.99 - 1.06) respectively. Samples of sorbent sample tube and sep-pak xposure aldehyde sampler turned out to be stored at refrigerator, according to storage test results. Measurement methods of HPLC-UVD, GC-NPD, GC-FID, according to results of precision for the combined sampling and analytical procedure, became acceptable to OSHA evaluation standard. Field test using exposure chamber met the NIOSH overall uncertainty recommendation(less than 25%). Overall uncertainty of Sepak-HPLC(UVD), Tube-GC(NPD), Tube-GC(FID) is 11.0% - 17.0%. Consequently gas chromatography(GC-NPD, GC-FID) and high performance liquid chromatography(EPA TO-11) using 2,4-DNPH coated sampler for formaldehyde measurement turned out to be suitable to measure personal formaldehyde exposure at workplaces.