• Economic and Environmental Geology
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• v.22 no.1
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• pp.35-63
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• 1989

Geochemical characteristics of the Guryongsan (Ogcheon) uraniferous black slate show that this is an analogue to the conventional Chattanooga and Alum shales in occurrences. Whereas, its highest enrichment ratio in metals including uranium, among others, is explained by the cyclic sedimentation of the black muds and quartz-rich silts, and the uniform depositional condition with some what higher pH condition compared to the conditions of the known occurrences. The cyclic sedimentation, caused by the periodic open and close of the silled basin, has brought about the flush-out) of the uranium depleted water and the recharge with the new metal-rich sea water, which consequently contributed to the high concentration of metals in mud. The metal-rich marine black muds, which mostly occur in the early to middle Palaeozoic times, is attributed by the geologic conditions which related to the atmospheric oxygen contents, and these are scarcely met in the late Precambrian and/or with the onset of Palaeozoic era in the geologic evolution of the earth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.1-7
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• 2017

Cobalt silicide was used as a counter electrode in order to confirm its reliability in dye-sensitized solar cell (DSSC) devices. 100 nm-Co/300 nm-Si/quartz was formed by an evaporator and cobalt silicide was formed by vacuum heat treatment at $700^{\circ}C$ for 60 min to form approximately 350 nm-CoSi. This process was followed by etching in $80^{\circ}C$-30% $H_2SO_4$ to remove the cobalt residue on the cobalt silicide surface. Also, for the comparison against Pt, we prepared a 100 nm-Pt/glass counter electrode. Cobalt silicide was used for the counter electrode in order to confirm its reliability in DSSC devices and maintained for 0, 168, 336, 504, 672, and 840 hours at $80^{\circ}C$. The photovoltaic properties of the DSSCs employing cobalt silicide were confirmed by using a simulator and potentiostat. Cyclic-voltammetry, field emission scanning electron microscopy, focused ion beam scanning electron microscopy, and energy dispersive spectrometry analyses were used to confirm the catalytic activity, microstructure, and composition, respectively. The energy conversion efficiency (ECE) as a function of time and ECE of the DSSC with Pt and CoSi counter electrodes were maintained for 504 hours. However, after 672 hours, the ECEs decreased to a half of their initial values. The results of the catalytic activity analysis showed that the catalytic activities of the Pt and CoSi counter electrodes decreased to 64% and 57% of their initial values, respectively(after 840 hours). The microstructure analysis showed that the CoSi layer improved the durability in the electrolyte, but because the stress concentrates on the contact surface between the lower quartz substrate and the CoSi layer, cracks are formed locally and flaking occurs. Thus, deterioration occurs due to the residual stress built up during the silicidation of the CoSi counter electrode, so it is necessary to take measures against these residual stresses, in order to ensure the reliability of the electrode.

• Journal of Nutrition and Health
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• v.7 no.2
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• pp.53-63
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• 1974

For the elucidation of the nutritional status of residences of apartments located in various areas in Seoul city, the food and nutrition survey was undertaken by the graduate students from Department of Food & Nutrition, Ewha Womans University in 1973. The socioeconomic stratification was mainly considered for the selection of sample apartments included in this study. Hangang Mansion, KIST, Munwhachon & Bukahyun apts were selected in this respect. A. Common living circumstances. Through the questionaries, author concluded nutritional concept on everyday food life as follows; 1. Higher income seems less effective in everyday food life on the nutritional view point than higher education does. 2. It needs to be urgently improved to be accustomed to use exact measuring concept of foods when they cook. 3. It needs to be improved to serve meals for individual portion at meal table, because the portion control at meal table will effect to national food policy. B. Nutrition Survey. Average daily calroie intake was the highest in Hangang Mansion and lowest in Bukahyun apt., in accordance with their economic living standard, but most of their calorie intakes were lower than the R.D.A. (3000ca1 for male, 2200 Cal for female). But the composition ratio of the total calorie intake was near to the ideal, carbohydrate 60%, protein 15%, fat 25%. Although there were differences in their economic living situations in urban area, most people ingested relatively good quality and large amounts of protein and fat. Vitamin A and Niacine intake exceeded the R.D.A., but the intake of Ca, Thiamine, Riboflavin, Ascorbic Acid were far less than that of R.D.A. C. food Intake. Amounts of total daily food intake were highest in Bukahyun apt. and lowest in Hangang Mansion. These showed adverse aspects to the total calorie intakes and their income levels. The ratio of cereals, $40%{\sim}50%$ of the total food intake, was higher than any other kinds of foods in all apartments. Among the other foods except cereals, there represented the highest level of meats in Hangang Mansion and KIST apt., while intake of Kimchies were highest in Munwhachon and Bukahyun apt. In the case of vegetables and fruits intake, the ratio of them in Hangang Mansion and KIST apt. were high, on the other hand the ratio of starchy roots appeared lowest in Hangang Mansion. For the main sources of protein, meats were ingested in Hangang Mansion and KIST apt., meats and fishery were used in Munwhachon apt., and beans were eaten highly in their meals in Bukahyun apt. These food contents and distributions showed the significant differences not only their economic classes but also regional characteristics.

• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.69-79
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• 2007

The purpose of this study was to investigate the effects of composite resin restorations on the stress distribution of notch shaped noncarious cervical lesion using three-dimensional (3D) finite element analysis (FEA). Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072 ; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). ANSYS (Swanson Analysis Systems, Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid or flowable resin and each restoration was simulated with adhesive layer thickness ($40{\mu}m$) A static load of 500 N was applied on a point load condition at buccal cusp (loading A) and palatal cusp (loading B). The principal stresses in the lesion apex (internal line angle of cavity) and middle vertical wall were analyzed using ANSYS. The results were as follows 1. Under loading A, compressive stress is created in the unrestored and restored cavity. Under loading B, tensile stress is created. And the peak stress concentration is seen at near mesial corner of the cavity under each load condition. 2. Compared to the unrestored cavity, the principal stresses at the cemeto-enamel junction (CEJ) and internal line angle of the cavity were more reduced in the restored cavity on both load con ditions. 3. In teeth restored with hybrid composite, the principal stresses at the CEJ and internal line angle of the cavity were more reduced than flowable resin.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.921-929
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• 2004

Dietary intake of whole grains, vegetable and fruit is known to reduce the degenerative chronic diseases, such as cancer and cardiovascular diseases. Antioxidative and antimutagenic effects of the ethanol extract of Korean Millet, Buckwheat, Sorghum and Job's tears were examined by inhibition against iron-induced linoleate per-oxidation, DPPH (1,l-diphenyl-2-picrylhydrazyl) radical generation and MDA-BSA (malondialdehyde-bovine serum albumin) conjugation, and Ames test using Salmonella. Buckwheat showed the strongest antioxidative effect in three different systems among these four grains, but it showed the lowest antimutagenic effect. Sorghum was the second to Buckwheat in iron-induced linoleate peroxidation inhibition activity and DPPH radical scavenging activity, and showed very good direct-antimutagenic effect in 2-Nitrofluorene treated Salmonella Typhimurium TA98 and indirect-antimutagenic effect in 2-Anthramine treated Salmonella Typhimurium TA98 and TA100 with hepatic S9 mixture. Millet showed the strongest antimutagenic effect in Salmonella Typhimurium TA98 and TA 100 with or without S9. Buckwheat contained the highest total flavonoids and polyphenols, 1.14 mg/g and 3.71 mg/g, respectively. Total flavonoid content in these four grains was negatively correlated with $IC_{50}$/ for DPPH radical scavenging antioxidative effect significantly (r=-0.9924, p=0.0076), but not with antimutagenic effect.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.958-964
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• 2004

This study examined the effects of maternal calcium intake levels on mineral metabolism during pregnancy and lactation. Five week-old female Sprague-Dawley rats were fed normal Ca (NCa, 0.5%) and low Ca (LCa, 0.15%) diets for 5 weeks during preconception. The low Ca intake group was divided into three groups and fed low Ca (0.15%), normal Ca (0.5%) and high Ca (1.5%) diets for 6 weeks during pregnancy and lactation. All of the rats were mated with normal male rats. The control group was consistently fed a normal Ca diet for 11 weeks. Pups were adjusted to 10 per dam. After weaning, dams and their weaned rats were sacrificed. We measured total protein, albumin, alkaline phosphatase and mineral content in serum and weight, length, breaking force, ash and mineral content in bone and kidney. There was no significant difference in weight gain and food intake among the groups. Serum total protein and albumin were in the normal range but slightly decreased with a low Ca diet during preconception. Calcium supplementation above normal level increased bone weight, Ca content and breaking force in femur of maternal and their weaned rats. However, high maternal Ca intake significantly decreased Mg and Fe contents in maternal serum and bone and Mg and Zn contents in serum of weaned rats. Also, it induced Ca, P and Mg deposit in maternal kidney. Our experimental results suggest that Ca deficiency during preconception may deteriorate bone status of mother and their offsprings. Moreover, high Ca supplementation during pregnancy and lactation may lead to disturb mineral metabolism in bone and other tissues.

• Journal of Korean Society of Forest Science
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• v.79 no.4
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• pp.367-375
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• 1990

In order to determine the effects of bedrock, organic matter, calcium and iron oxide on the soil aggregation, this research has performed with soils from bedrock regions of Limestone, Granite and Granite gneiss. This research was also to estimate how organic matter, calcium and iron oxide influence on soil aggregation under different forest conditions in various bedrock regions. And it also had a purpose to rate physical factors relevant to soil aggregation, their characteristics and aggregate diameter which closely relates to stabilities in the process of soil erosion. The following conclusions have been drawn in response to the overall research objectives. The rates of the soil aggregation on different bedrock regions were 21% in Limestone bedrock, 19.8% in Granite bedrock and 9.9% in Granite gneiss bedrock. A main factor in soil aggregation was the orgainc matter content in soils and the rate of soil aggregation increased in the constant proportion with the organic matter content. The relation could be formulated into Y=4.31X-4.37(Y : aggregation ratio X : organic matter content). The soil aggregation ratio under the deciduous forests eras higher than that under the coniferous forests. It was considered that this resulted from differences in organic matter content. Soil aggregates with larger diameter than 0.5mm were found more in Limestone bedrock than other smaller size soil aggregates of 0.25mm diameter were more distributed in Granite gneiss bedrock. Granite bedrock region had normal distribution in soil aggregate sizes with the highest frequency of 0.5mm diameter. Calcium and iron oxides had only partial influences on the soil aggregation in some specific conditions. But in Limestone bedrock region calcium influenced on the soil aggregation with the organic matter content.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.4 s.54
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• pp.289-293
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• 2005

Nowadays there are many sun protection cosmetics including organic or inorganic UV filter as an active ingredient. Chemically stable inorganic sunsEreen agents, usually metal oxides, we widely employed in high SPF products. Titanium dioxide is one of the most frequently used inorganic UV filters. It has been used as pigments for a long period of cosmetic history. With the development of micronization techniques, it becomes possible to incorporate titanium dioxide in sunscreen formulations without whitening effect and it becomes an important research topic. However, there are very few works related to quantitations of titanium dioxide in sunscreen products. In this research, we analyzed amounts of titanium dioxide in sunscreen cosmetics by adapting redof titration, reduction of Ti(IV) to Ti(III) and reoxidation to Ti(IV). After calcification of other organic ingredients of cosmetics, titanium dioxide is dissolved by hot sulfuric acid. The dissolved Ti(IV) is reduced to the Ti(III) by adding aluminum metals. The reduced Ti(III) is titrated against a standard oxidizing agent, Fe(III) (ammonium iron(III) sulfate), with potassium thiocyanate as an indicator In order to test accuracy and applicability of the proposed method, we analyzed the amounts of titanium dioxide in four types of sunscreen cosmetics, such as cream, make-up base, foundation and powder, after adding known amounts of titanium dioxide $(1{\sim}25w/w%)$. The percent recoveries of the titanium dioxide in four types of formulations were in the range between 96 and 105%. We also analyzed 7 commercial cosmetic products labeled titanium dioxide as an ingredient and compared the results with those of obtained from ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry), one of the most powerful atomic analysis techniques. The results showed that the titrated amounts were well coincided with the analyzed amounts of titanium dioxide by ICP-AES. Although instrumental analytical methods, ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) and ICP-AES, are the best for the analysis of titanium, it is hard to adopt because of their high prices for small cosmetic companies. It was found that the volumetric method presented here gat e quantitative and reliable results with routine lab-wares and chemicals.

• Food Science and Preservation
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• v.19 no.6
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• pp.951-956
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• 2012

In this study, the effects of the use of a starter on radish soaked at $4^{\circ}C$ for 28 days using two kinds of domestic sun-dried salt (white and gray salt) were determined. As a result, the moisture contents of the radish soaked with white and gray salt were 7.93 and 4.50%, respectively. The salinity levels were found to be equal (90%). No significant difference was found between the two groups in terms of the mineral contents of the salts therein ($37812.41{\pm}1922.95$ and $39755.13{\pm}1205.70$ mg/100 g, respectively). However, iron and zinc contents of gray salt were higher than those of white salt while the calcium, potassium, and magnesium contents were lower than those of white salt. After the addition of the starter, the sugar content increased, the pH decreased, and the total acidity rapidly decreased compared with the non-starter group during fermentation. The total microorganism count of the two groups increased during the fermentation period of 28 days. From the initial fermentation for 7 days, the lactic acid bacteria in the non-starter group increased while those in the leuconostoc starter group steadily increased within the whole fermentation period. The Leuconostoc spp. in non-starter group increased, but that in the starter group decreased to pH 4.0 on day 14.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.25-32
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• 1998

To characterize the growth environment, inorganic composition and morphological chracteristics of leaves of Korean tea plant, soil and tea leaf samples were collected from 15 locations and analyzed. The chemical characteristics of soils were in range of pH 4.09~6.15, OM 23.9~72.6g/kg, available phosphate less than 300mg/kg, K $0.8{\sim}2.5cmol^+/kg$, Na $tr{\sim}0.17cmol^+/kg$, Ca $1.0{\sim}6.2cmol^+/kg$, and Mg $0.3{\sim}2.1cmol^+/kg$. The contents of Ni. Cr, Zn. Cu, Pb, and Cd were at the level less than natural content in upland soil. Most of the sample soils were sandy loamy and loamy texture. The native tea plants were mainly grown in bamboo thicket or in forest. The leaf sizes of tea plants were $6.85{\pm}1.75{\times}2.6{\pm}0.5cm$, lateral vein number $14.2{\pm}2.7$, and crenated number $58.5{\pm}11.2$, and the leaf color was thin to dark green. The contents of $NH_4{^+}$, $Na^+$, $K^+$, $Mg^{2+}$ and $Ca^{2+}$ in tea leaves were in range of 30.5~47.7, 45.5~164.5, 16,998~25,431, 1.590~2,392 and 1,085~1,958mg/kg, respectively. The contents of $F^-$, $Cl^-$, $NO_3{^-}$, $PO_4{^{3-}}$ and $SO_4{^{2-}}$ were in range of 21.2~63.2, 126.4~257.9, 108.5~185.9, 1,270~1.819, and $954{\sim}1,670mg/kg$, respectively. The leaf size of native tea plant grown widlly in Shunchun Changchun-ri, Hwasun Ssangbongsa, Kuryoi Chonunsa, Bosong Daewonsa and Namhae Boriam was as large as those of Yabukita. Japan cultiver, grown at Kangjin Jangwon tea field.