• Korean Journal of Veterinary Research
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• v.32 no.1
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• pp.153-156
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• 1992

Serum chemical values were determined in blood samples obtained from 179 normal, healthy Jindo dogs of both sexes that ranged in age from 3 months to 10 years. Female dogs had higher total protein and albumin values than their male counterparts. Age-related differences were detected for serum proteins, inorganic phosphate, glucose, and blood urea nitrogen levels. The GGT level Was within the normal range in dogs.

• Journal of The Geomorphological Association of Korea
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• v.23 no.2
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• pp.95-108
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• 2016

Several flights of marine terraces were developed along the Eastern coast of Korea (Gangneung-Donghae). Various dating techniques have been applied to determine the age of these terraces, with a view to better understand the regional uplift history. In this study, we compare the major element compositions of the terrace deposits and modern beach sediments to estimate the relative formation age of these terraces. We observed a discernible difference in major element geochemistry between modern beach sediments and various elevated terrace deposit (i.e. palaeobeach sediments). In general, weathering properties of marine terrace sediments are expected to be affected by the formation ages of terraces, and here, we confirm that the chemical composition are indicative of the relative age of the terraces in this region.

• Journal of The Korean Astronomical Society
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• v.18 no.2
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• pp.41-69
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• 1985

For the well observed 16 globular clusters with known metal abundance (Z), the helium abundances (Y) and ages are determined by various methods, and the relations between Y, Z and age are examined. The luminosity $L_{RR}$ of RR Lyrae stars is known to be dependent of evolutionary models and pulsation theory in the sense that the pulsation theory and horizontal branch (HB) models yield the anticorrelation between $L_{RR}$ and Z whereas main sequence (MS) and red giant branch (RGB) models yield the direct correlation between them. Similarly the anticorrelation between Y and Z is obtained from the HB models and pulsation theory whereas the direct correlation between them is obtained when the RGB model is applied. The current evolutionary models yield the anticorrelation between Z and age of clusters whenever the direct correlation between Y and Z holds. However when the anticorrelation between Y and Z is applied for age determination, the similar age of clusters is obtained as shown by Sandage (1982b). The ages, which are determined by the fitting of C-M diagrams to isochrones in the ($M_v$, B-V)-plane, suggest the two different chemical enrichment processes, which could be accounted for by the disk-halo model for the chemical evolution of the Galaxy (Lee and Ann 1981). Also it is known that the R-method is very useful for Y-determination and the derived Y's show the increasing rate of $\frac{{\Delta}Y}{{\Delta}Z}{\simeq}0.5$ which is comparable to the observed value of $\frac{{\Delta}Y}{{\Delta}Z}{\simeq}0.3$ from HII regions and planetary nebulae by Peimbert and Torres-Peimbert (1976). In this case, the age-metallicity relation of globular clusters could be explained by the disk-halo model.

• Journal of the Korean Chemical Society
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• v.37 no.12
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• pp.1068-1075
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• 1993

Catalase activities were assayed on the leaves and roots of Tomato (Lycopersicum esculentum) as a function of age for 1 year after germination. The enzyme activities of root tissue demonstrated to be insignificant through all stages of development. On the other hand, the catalase activities of leaf peroxisomal fractions showed remarkable changes with peak value of 76 ${\mu}mol$/ml/min at germination stage within 2 weeks growth, 7.2 ${\mu}mol$/ml/min at adult stage around 4∼5 months growth and very small activities at aged period around 11∼12 months growth. It is suggested that there may be two factors concerning such catalase activities in relation with age, firstly the glyoxisomal reactions including glyoxylate cycle and $\beta$-oxidation at germination stage and secondly photosynthesis hereafter seemed to affect age dependent changes of catalase activity by producing coincident amount of $H_2O_2$. In addition, NADPH coenzyme was found to have ability to restore catalytic acitivity of inactivated catalase (compound II) at all stages of development except old age, indicating NADPH would play a role as catalase protector against deleterious substrate,$H_2O_2$.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.28.1-28.1
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• 2015

Open clusters are one of stellar systems consisting of a few hundreds to thousands of stars. The cluster members are, in general, believed to be a coeval stellar population at the same distance, and therefore they have almost the same properties in chemical composition and kinematics. Owing to these advantages, the clusters are utilized in many astronomy studies, such as the calibrations of distance and stellar age scales, assessments of stellar evolution theories, and the chemical evolution of the Galactic disk. Young open clusters are, inter alia, superb objects to study star formation process as most of stars are known to be formed in clusters. In this talk, I will review the uses of these young open clusters in star formation studies based on the ongoing work of our research group on the stellar initial mass function, an age spread problem, mass accretion rate of pre-main sequence stars, and a feedback of high-mass stars on surroundings.

• Analytical Science and Technology
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• v.17 no.3
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• pp.271-277
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• 2004

The aim of this study was to investigate questioned documents written with blue or black ballpoint pen on paper by nondestructive technique. In this work, 21 blue and 22 black ballpoint pen inks which were purchased on different brands were analyzed by using Microspectrophotometry (MSP). The reflectance spectra were obtained from these ink samples and their shapes and the wavelength of the maximum intensity were compared. In the blue and black ballpoint pen inks, the discriminating powers (DP) were 0.85 and 0.61, respectively. The changes of the reflectance intensity at their wavelength of maximum intensity and their shapes appeared according to the exposure time to sunshine in a laboratory, especially in the blue ballpoint pen inks. Therefore it is possible to distinguish ink entries on the same paper with the relative age in case of questioned letters written with blue ballpoint pen.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.129-130
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• 2021

In order to solve the problem of low early-age compressive strength of high volume fly ash concrete. This paper studies the effect of 2% sodium sulfate (Na₂SO₄) as a chemical activator on the paste with 40% fly ash content and a water-binder ratio of 0.30. The results indicate that the addition of Na₂SO₄ can effectively improve the early-age compressive strength of the fly ash-cement system, and the strength improvement rate on the first day reached nearly 70%. In addition, calorimetric analysis reveals that the incorporation of Na₂SO₄ promotes the early hydration of cement and fly ash, increases the cumulative hydration heat and delays the heat peak of the aluminum phase.

• Geomechanics and Engineering
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• v.16 no.1
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• pp.105-112
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• 2018

This paper presents results of a compressive investigation conducted on weathered soil stabilized with ground bottom ash (GBA) and red mud (RM). The effects of water/binder ratio, RM/GBA ratio, chemical activator (NaOH and $Na_2SiO_3$) and curing time on unconfined compressive strength of stabilized soils were examined. The results show that the water/binder ratio of 1.2 is optimum ratio at which the stabilized soils have the maximum compressive strength. For 28 days of curing, the compressive strength of soils stabilized with alkali-activated GBA and RM varies between 1.5 MPa and 4.1 MPa. The addition of GBA, RM and chemical activators enhanced strength development and the rate of strength improvement was more significant at the later age than at the early age. The potential environmental impacts of stabilized soils were also assessed. The chemical property changes of leachate from stabilized soils were analyzed in terms of pH and concentrations of hazardous elements. The observation revealed that the soil mixture with ground bottom ash and red mud proved environmentally safe.

• The Bulletin of The Korean Astronomical Society
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• v.9
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• pp.10.2-10.2
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• 1984

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1041-1044
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• 2008

The addition of chemical inert filler in blended cement, such as limestone or chemical inert silica fume, will produce a physical effect on cement hydration. Due to the high surface area of inert filler in the mixtures, it provides sites for the nucleation and growth of hydration products, thus improving the hydration rate of cement compounds and consequently increasing the strength at early age. This paper proposes a model of hydration of Portland cement blended with chemical inert filler. This model considers the influence of water to cement ratio, cement particle size, cement composition and addition of chemical inert filler on hydration. The heat evolution, degree of hydration and porosity are obtained as accompanied results in hydration process. The prediction results agree well with experiment results.