• YAKHAK HOEJI
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• v.47 no.6
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• pp.461-468
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• 2003

A method is described for measuring clinically relevant levels of glucose in a pH 7.4 phosphate buffer by nearinfrared (NIR) absorption spectroscopy. Three types of NIR spectrometer, dispersive type, photo-diode array (PDA) type, and fourier transform (FT) type spectrometer were used and the performance was compared. Spectra were collected with a cuvette cell or quartz liquid fiber of 1 mm or 2 mm optical pathlength as transmittance method. Glucose absorption band appeared at second overtone, first overtone, and combination region for all systems. By use of the multivariate technigue of partial least squares (PLS) regression, glucose concentrations can be determined with a 16, 44, and 9.1 mg/d l standard error of prediction for dispersive type, photo-diode array type, and fourier transform type system, respectively. Sensitivity of spectrometer was evaluated by absorbance for the difference of 10 mg/d l glucose. Three absorption bands, second overtone, first overtone, and combination region were suited to three types systems, dispersive type, photo-diode array type, and fourier transform type systems, respectively. This investigation showed that three types NIR spectrometer were proper method for identification and quantitative analysis of glucose and possible for noninvasive blood glucose monitoring.

• Journal of the Korean Home Economics Association
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• v.34 no.5
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• pp.85-98
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• 1996

This study was undertaden to investigate the effect of salted anchovy during Puchukimchi fermentation, Puchukimchi is a kind of Korean kimchi made with Puchu(Allium odorum L.). For this purpose, the Puchukimchi with 10%, 15% and 30% salted anchovy was investigated by measuring physicochemical, microbiological and sensory characteristics during fermentation at 5$\pm$2$^{\circ}C$ up to 60 days, In the palatable period, pH was remarkably decreased to the range of 4.8-5.16 and total acidity was increased 2-3 times more than that of initial period. Reducing sugar contents in Puchukimchi increased up to 22days and remarkably decreased. The changing pattern of vitamin C drawed sigmoidal curve, invreasing significantly in the palatable period. The content of lactic acid was a little in the initial fermentation period but increased 3-13 times more than that of the initial fermentation period in the palatable period. The content of malic acid and citric acid were decreased as the fermentation progressed. The contents of Ca, Mg and K was gradually decreased and Na was increased as the fermentation progressed in the same period. There were similiar changes in the number of lactic acid bacteria and total cell number. The score of overall taste, overall acceptability in evaluation during fermentation was high in order of 15%, 10%, 30% level of salt fermented anchovy.

• Transactions of the Society of Information Storage Systems
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• v.6 no.2
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• pp.79-82
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• 2010

In optical imaging systems, such as microscopes, high resolution exposure systems, and optical storage devices, higher optical resolution is a requirement. One of the promising technologies that is able to satisfy this requirement with relatively simple construction and reliable performance are, solid immersion lens (SIL)-based near-field (NF) optical systems. High NA optical systems using annular apertures have been investigated as one solution to achieve higher resolutions and an extended focal depth. By applying an optimized annular aperture to convention SIL optical head resolution can be increased by approximately 20%. This novel SIL-based near-field optics will be verified through experiments such as measuring focused beam spot profiles and observing the topology of a measurement sample. The studied SIL-based near-field optics can be applicable to not only next generation optical storage device but also high resolution microscopy and pattering technologies.

• Nuclear Engineering and Technology
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• v.32 no.5
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• pp.446-456
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• 2000

Laser induced photoacoustic, fluorescence, and photon correlation spectroscopies were applied to the chemical characterization of radionuclides in connection with the radiowaste treatment and disposal. Their measuring principles and systems were briefly described together with their advantages over conventional spectroscopies. Also, other applications of lasers are introduced. Laser induced photoacoustic spectra were measured for a P $r^{3+}$ solution with a very low molar absorptivity. The detection sensitivity was 4.3 $\times$10$^{-5}$ c $m^{1}$ and was 100 times better than that of a UV/VIS spectrophotometer. The Eu(III) excitation spectra($^{7}$ $F_{0}$ longrightarrow $^{5}$ $D_{0}$ transition) were measured for Eu(III)-phthalate complexes using laser fluorescence spectroscopy, showing that only two species, 1:1 and 1:2 complexes, are present in the Eu(III)-phthalic acid system. The size and size distribution for colloidal humic acids and Eu(III)-humate colloids was determined using photon correlation spectroscopy. The presence of Eu(III) enhanced the aggregation of humic acids.s.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.858-863
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• 1998

The Mixed effect of Salvia miltiorrhiza and Glycyrrhiza uralensis(SG) on kimchi fermentation was investigated by measuring changes of physicochemical, icrobiological and sensory qualities of kimchi during fermentation. The pH of SG-added kimchi was a little higher than that of control during the fermentation. Titratable acidity, viable cell of total bacteria and lactic acid bacteria in mixed medicinal herbs(SG) added kimchi were changed more slowly than those in control. The inhibitory effect of the mixture on kimchi fermentation was increased as the concentration of the mixture was increased from 1% to 5%. Total bacteria and lactic acid bacteria of 3% and 5% SG-added kimchi reduced to 1.3~2.9 and 1.2~4.0 log10 cycle after 15 days fermentatin compared to control. The changes in texture of SG-added kimchi was a higher and sour taste of SG-containing kimchi excepts of 1% SG-added kimchi was more weak than that of control. Sensory score of flavor and overall acceptability did not show any significant difference between SG-added kimchi and control during fermentation. But SG-added kimchi decreased its sensory quality by 5% the other kimch.

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.574-578
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• 1993

Laser-induced photoacoustic spectroscopy (LIPAS), which utilizes the photothermal effect that results from nonradiative relaxation of excited state molecules, was used in the speciation analysis of the complexes of neodymium(III) and water soluble synthetic polyelectrolyte, poly methacrylic acid (PMAA), in 0.1 M $NaClO_4$ at pH of 6.0. The minimum detection limit of Nd(III) by LIPAS was $5.O{\times}10^{-6}$ M. Experiment was carried out at low concentration ratio of Nd(III) to PMAA to assure that 1 : 1 complexes predominate. The bound and free Nd(III) species were characterized by measuring nonradiative relaxation energy of the excited states $(^2GM{7/2}\;and\;^4G_{5/2})$ to the metastable state $(^4G_{3/2})$. Two species were quantified by deconvolution of the mixed spectrum using their respective reference spectra. The conditional stability constant measured by LIPAS was 5.52 L$mol^{-1}$.

• Environmental Engineering Research
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• v.24 no.3
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• pp.382-388
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• 2019

Although nanobubbles attract significant attention, their characteristics and applications have not been thoroughly defined. There are diverse opinions about the definition of nanobubbles and controversy regarding methods that verify their characteristics. This study defines nanobubbles as having a size less than $1{\mu}m$. The generation of these sub-micron (nano) bubbles may be verified by induced coalescence or light scattering. The size of a sub-micron (nano) bubbles may be measured by optical, and confocal laser scanning microscopy. Also, the size may be estimated by the relationship of bubble size with the dissolved oxygen concentration. However, further research is required to accurately define the average bubble size. The zeta potential of sub-micron (nano) bubbles decreases as pH increases, and this trend is consistent for micron bubbles. When the bubble size is reduced to about 700-900 nm, they become stationary in water and lose buoyancy. This characteristic means that measuring the concentration of sub-micron (nano) bubbles by volume may be possible by irradiating them with ultrasonic waves, causing them to merge into micron bubbles. As mass transfer is a function of surface area and rising velocity, this strongly indicates that the application of sub-micron (nano) bubbles may significantly increase mass transfer rates in advanced oxidation and aeration processes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.2
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• pp.122-128
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• 2024

We investigated the quality of 10 commercial eorigul-jeot, salt-fermented oysters with seasoning, by measuring their chemical composition and bacterial concentrations. The Eorigul-jeot had 5.07-6.06 pH (mean, 5.63), of 1.92-4.74% salinity (mean, 3.36%), 7.01-14.70 mg/100 g volatile basic nitrogen (mean, 11.91 mg/100 g), 139.22-267.11 mg/100 g amino acid nitrogen (mean, 212.69 mg/100 g), and 1.02-1.65 g/100 g total acidity (mean, 1.24 g/100 g). The total viable and lactic acid bacterial counts were 5.7×10⁴-8.7×10⁵ and 2.7×10³-2.0×10⁵ CFU/g, respectively, and fecal coliform was detected in only one Eorigul-jeot sample. Bacillus cereus and Clostridium perfringens were detected in two samples, and all Eorigul-jeot samples were negative for Staphylococcus aureus and Vibrio parahaemolyticus. These results strongly suggest the need to monitor food-poisoning bacteria in commercial Eorigul-jeot to ensure consumer health.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.469-478
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• 2004

Pig slurry, urine and fermented liquid manure were evaluated measuring electrical conductivity (EC), dry matter (DM) contents and other components. Samples were collected during a period from February to April, 2001: slurry samples from 70 storage tanks, urine samples from 19 and 20 fermented liquid manure samples from 109 pig farms in Jeju. Samples were analyzed for pH, EC, DM, $NH_4$-N, K, P, Ca, Mg, Na, BOD, S-S, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn and OM. Relationships between EC or DM and various mineral and $NH_4$-N contents were examined using linear regression. EC, DM, all mineral contents and $NH_4$-N were higher in slurry samples than in urine or fermented liquid manure. EC, $NH_4$-N, Ca, Mg and Na concentration was similar in urine and fermented liquid manure, but K and DM values in liquid manure were twice as much as in urine. P concentration was higher in urine than in liquid manure. $NH_4$-N and Na in slurry, $NH_4$-N in urine and $NH_4$-N, P and Ca in fermented liquid manure were highly correlated with EC, while $NH_4$-N, P, Ca and Mg in slurry, $NH_4$-N and Ca in urine, and K, P, Ca, Mg, and Na in fermented liquid manure with DM (P<0.05). BOO in slurry (22,520 mg/mL) was higher than that in urine (4,763) and fermented liquid manure (2,701). Results indicated that slurry is a better fertilizer source than urine or fermented liquid manure. However, slurry may pollute soil more than urine or fermented liquid manure when applied to land, although the levels are not above the permit.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.744-751
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• 1995

Effect of licorice root(Glycyrrhiza Uralensis Fischer) on the Dongchimi(watery radish kimchi) fermentation was investigated by measuring physicochemical, microbiological and sensory properties during fermentation up to 41 days. Dongchimi with the various levels(0, 0.5, 1.0, 1.5%) of licorice root was fermented at two temperatures : Group A was fermented at $10^{\circ}C$ and group B was fermented at $4^{\circ}C$ after keeping at room temperature($16{\pm}0.5^{\circ}C$) for 24 hours. During the fermentatiion, pH was slowly lowered in all Dongchimi samples and pH of Dongchimi added licorice root was a little higher than that of Dongchimi without licorice root. Total acidity of group A was slightly larger than that of group B and Dongchimi added licorice root showed small content than that of Dongchimi without licorice root. Reducing sugar content was reached maximum value in 13 days of fermentation in Dongchimi added licorice root of group A and B, group A decreased remarkably in 32 days of fermentation in all samples and group B was maintained in the rest sample except for Dongchimi without licorice root and Dongchimi added 1.5% licorice root. Total vitamin C of Dongchimi added licorice root was slightly higher than that of Dongchimi without licorice root of two groups. Lightness lowered gradually with the fermentation and Dongchimi without licorice root decreased a little than that of Dongchimi added licorice root. The number of lactic acid bacteria in Dongchimi added licorice root was more numerous than that of Dongchimi without licorice root. As a result of the sensory evaluation, group B showed higher scores than group A and Dongchimi added 0.5% licorice root was the most preferable one.