• Analytical Science and Technology
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• v.20 no.1
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• pp.1-9
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• 2007

The BOD (biochemical oxygen demand) sensor was fabricated by covering a dissolved oxygen (DO) probe with a microbe-impregnated membrane and a dialysis membrane. Various microorganisms isolated from the soils, water and activated sludge have been evaluated for measuring biochemical oxygen demand (BOD); Bacillus species HN24 and HN93 were selected as they exhibited rapid oxygen consumption and fast recovery. Improved BOD sensor could be prepared by using mixed microbes (Bacillus subtilis, Bacillus sp. HN24 and Bacillus sp. NH93) and silicon rubber gas-permeable membrane for DO probe, and by bubbling 50% $O_2$ ($N_2$ valence) through background buffer solution. This system exhibited excellent analytical performance resulting in good linearity ($r^2=0.9986$) from 0 to 100 mg/L level of BOD.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.2
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• pp.170-177
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• 2012

A force/torque sensor using carbon fiber plate was designed and developed to make the sensor be able to measure a wide range of multi degree of force and torque. Using carbon fiber plate of 0.3 mm thickness, the sensor was designed and developed, which has a ${\mu}N$ level order of resolution and about 0.01 N ~ 390 N of wide measurement range. The elastic deformation part has a tripod plate structure and strain gauges are attached on the part to detect the force/torque. The coefficient of determination for the sensor is over 0.955 by the calibration experiment so that the linearity of the sensor is confirmed to be good. Also, experiments on applying 0.005 ~ 40 kg (0.05 ~ 390 N) to each axis were implemented and the sensor is proved to be safe under a high load. Finally, to verify the function calculating the direction of load vector, the directions of various load vectors which have the same magnitude but different directions and the directions of the calculated load vectors are compared and analyzed to accord well.

• Bulletin of the Korean Chemical Society
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• v.10 no.5
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• pp.437-442
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• 1989

The cmc's of sodium dodecyl sulfate (SDS)/Triton X-100 surfactant mixtures were determined by surface tension measurement at various surfactant compositions. The cmc values were lower than those predicted from ideal mixture. The regular solution theory was applied to calculate the interaction parameter, micellar composition, and the activity coefficients of surfactants in the mixed micelle. The interaction parameter (${\beta}$) was - 2.1. The nonideality arised largely from decreased activity of SDS in the mixed micelle. The mean aggregation numbers (${\bar{n}}$) and micropolarity of hydrocarbon region of the mixed micelles were determined by luminescence probe techniques. The total aggregation number (${\bar{n}}_{SDS}+{\bar{n}}_{TX}$) in mixed micelles showed little dependency on the composition of the micelle. The apparent dielectric constant of the hydrocarbon region of the micelle vs micellar composition plot showed positive deviation from linearity. Emission and emission quenching of excited tris(2,2'-bipyridine)ruthenium(Ⅱ) cation, $(Ru(bpy)_3^{2+})$, by methylviologen ($MV^{2+}$) were also investigated in the mixed micellar solutions. The quenching rate was lowest when the mole fraction of SDS in the surfactant mixtures (${\alpha}_{SDS}$) is about 0.25 and highest at ${\alpha}_{SDS}$ = 0.85. This was explained in terms of combined effects of binding of the cations with the micelle and mobility of the bound cations on the surface of the micelles.

• The Korean Journal of Nuclear Medicine
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• v.33 no.1
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• pp.100-109
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• 1999

Purpose: Preamplifier and amplifier are very important parts for developing a portable counting or imaging gamma probe. They can be used for analyzing pulses containing energy and position information for the emitted radiations. The commercial Nuclear Instrument Modules (NIMs) can be used for processing these pulses. However, it may be improper to use NIMs in developing a portable gamma probe, because of its size and high price. The purpose of this study was to develop both preamplifier and amplifier and measure their performance characteristics. Materials and Methods: The preamplifier and amplifier were designed as a charge sensitive device and a capacitor resistor-resistor capacitor (CR-RC) electronic circuit, respectively, and they were mounted on a print circuit board (PCB). We acquired and analyzed energy spectra for Tc-99m and Cs-137 using both PCB and NIMs. Multichannel analyzer (Accuspec/A, Canberra Industries Inc., Meriden Connecticut, U.S.A) and scintillation detectors (EP-047(Bicron Saint-Gobain/Norton Industrial EP-047 (Ceramics Co., Ohio, U.S.A) with $2"{\times}2"$ NaI(T1) crystal and R1535 (Hamamatsu Photonics K.K., Electron Tube Center, Shizuoka-ken, Japan) with $1"{\times}1"$ NaI(T1) crystal were used for acquiring the energy spectra. Results: Using PCB, energy resolutions of EP-047 detectors for Tc-99m and Cs-137 were 12.92% and 5.01%, respectively, whereas R1535 showed 13.75% and 5.19% of energy resolution. Using the NIM devices, energy resolutions of EP-047 detector for Tc-99m and Cs-137 were measured as 14.6% and 7.58%, respectively. However, reliable energy spectrum of R1535 detector could not be acquired, since its photomultiplier tube (PMT) requires a specific type of preamplifier. Conclusion: We developed a special preamplifier and amplifier suitable for a small sized gamma probe that showed good energy resolutions independent of PMT types. The results indicate that the PCB can be used in developing both counting and imaging gamma probe.

• Korean Journal of Optics and Photonics
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• v.11 no.6
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• pp.452-456
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• 2000

A measurement unit and signal processing algorithm have been developed for predicting arterial oxygen saturation noninvasively. The measurement set-up was composed of a probe including light source and photodetector, optical signal processing section, LED driving circuit, PC interface software for data acquisition and data processing software. Light from the LED's was irradiated onto the finger nail bed and transmitted light was measured at different wavelengths. An effective baseline correction method was developed and measured data were analyzed by using various data processing methods and prediction algOlithms. For performance evaluation, a pulse oximeter simulator (Bio- Tek Instrument Inc.) was used as reference. The best performance in terms of the correlation coefficient and the standard deviation was obtained under the following conditions; when the arterial signals were computed in terms of area rather than peak-valley difference, and when the algorithm calculating by $In(I_p/I_v)/I_{avr}$ value for pulsation waveform was used. In in vivo test, prediction was improved when the developed baseline correction method was used. In addition, wavelengths of 660 nm and 940 nm provided better linearity and precision than wavelengths of 660 nm and 805 nm. 05 nm.

• Preventive Nutrition and Food Science
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• v.17 no.4
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• pp.274-279
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• 2012

For the quantitative analysis of genetically modified (GM) maize in processed foods, primer sets and probes based on the 35S promoter (p35S), nopaline synthase terminator (tNOS), p35S-hsp70 intron, and zSSIIb gene encoding starch synthase II for intrinsic control were designed. Polymerase chain reaction (PCR) products (80~101 bp) were specifically amplified and the primer sets targeting the smaller regions (80 or 81 bp) were more sensitive than those targeting the larger regions (94 or 101 bp). Particularly, the primer set 35F1-R1 for p35S targeting 81 bp of sequence was even more sensitive than that targeting 101 bp of sequence by a 3-log scale. The target DNA fragments were also specifically amplified from all GM labeled food samples except for one item we tested when 35F1-R1 primer set was applied. A reference plasmid pGMmaize (3 kb) including the smaller PCR products for p35S, tNOS, p35S-hsp70 intron, and the zSSIIb gene was constructed for real-time PCR (RT-PCR). The linearity of standard curves was confirmed by using diluents ranging from $2{\times}10^1{\sim}10^5$ copies of pGMmaize and the $R^2$ values ranged from 0.999~1.000. In the RT-PCR, the detection limit using the novel primer/probe sets was 5 pg of genomic DNA from MON810 line indicating that the primer sets targeting the smaller regions (80 or 81 bp) could be used for highly sensitive detection of foreign DNA fragments from GM maize in processed foods.

• Journal of Pharmaceutical Investigation
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• v.21 no.3
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• pp.133-141
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• 1991

The fluorescence characteristics of l-anilinonaphthalene-8-sulfonate (ANS) and 2-p-toluidinylnaphthalene-6-sulfonate (TNS) made the dyes useful probes for the determination of the polarity at the binding sites of several water-soluble polyparacyclophanes. Polyparacyclophanes used were 1,6,20,25-tetraaza[ 6.1.6.1]paracyclophane (CPM 44), 1,7,21,27 -tetraaza[7.1.7.1]paracyclophane (CPM 55). 1,7,21,27 -tetraaza-14,34-dioxa[7.1.7.1]paracyclophane (CPE 55) and 1,8,22,29-tetraaza-15,36-dioxa[8.1.8.1] paracyclophane (CPE 66). The fluorescence quantum yield, emission maximum, and half bandwidth of ANS or TNS obtained in a variety of solvent systems were plotted as a function of four kinds of empirical solvent polarity scales such as dielectric constant (D), (D-l)/(2D+1). Y and Z values. It was found that the Z-value-emission maximum $(\overline}V_F,\;cm^{-1})$ profile showed the most reliable linearity. ANS and TNS interacted with CPM 44, CPM 55, CPE 55. CPE 66. ${\alpha}-cyclodextrin$ (CyD) and ${\beta}-CyD$ in the aqueous solution, and from the emission maxima the polarities (Z-value) of their binding sites were calculated to be 92.65, 87.50, 93.35, 84.52, 94.36, and 90.48 for ANS, respectively. and 91.07, 89.68, 85.44, 86.74 and 87.6 for TNS except for ${\alpha}-CyD$, respectively.

• Journal of the Korean Magnetics Society
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• v.16 no.3
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• pp.157-162
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• 2006

In this study, a high sensitive giant magnetoresistance-spin valve (GMR-SV) bio-sensing device with high linearity and very low hysteresis was fabricated by photolithography and ion beam deposition sputtering system. Detection of the Fe-hemoglobin inside in a red blood and magnetic nanoparticles using the GMR-SV bio-sensing device was investigated. Here a human's red blood includes hemoglobin, and the nanoparticles are the Co-ferrite magnetic particles coated with a shell of amorphous silica which the average size of the water-soluble bare cobalt nanoparticles was about 9 nm with total size of about 50 nm. When 1 mA sensing current was applied to the current electrode in the patterned active GMR-SV devices with areas of $5x10{\mu}m^2 $ and $2x6{\mu}m^2 $, the output signals of the GMRSV sensor were about 100 mV and 14 mV, respectively. In addition, the maximum sensitivity of the fabricated GMR-SV sensor was about $0.1{\sim}0.8%/Oe$. The magnitude of output voltage signals was obtained from four-probe magnetoresistive measured system, and the picture of real-time motion images was monitored by an optical microscope. Even one drop of human blood and nanopartices in distilled water were found to be enough for detecting and analyzing their signals clearly.