• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.105-106
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• 2023

Using the limestone powder as material that can alternate the clinker, it seems to get positive effect as filler and enhance workability of cement, but the amount of replacement can affect compressive strength of cement. This study was evaluated the effect of limestone mixed cement fineness and SO₃ content on cement mortar. As a result of measuring the compressive strength, it showed 93% compared to the compressive strength of Plain 28 days at fineness 4,400 and SO₃ 2.6%. It is judged that additional research is necessary to express the strength equivalent to that of Plain.

• Journal of the Korean Society of Tobacco Science
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• v.10 no.1
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• pp.3-9
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• 1988

Effect of several nitrogen fertilizer sources on the chlorine absorption by the burley tobacco plants was investigated under the field and pot condition. The nitrogen sources included compound fertilize.(containing 3.9% NH4-N and 6.1% NH2-N), (NH4)2SO4, NaNO3. (NH2)2CO and NH4NO3. The chlorine content of leaf during growing stage was high in (NH4)2SO4 plot , and the differences among nitrogen sources was remarkable at maximum growing stage. The chlorine content of cured leaf was high in (NH4)2SO4 plot. When the (NH4)2SO4 was applied, the total alkaloid content of cured leaf was increased and the color of cured leaf became undesirable with the increment of leaf chlorine. The yield, quality and value of cured leaf were high in NaNO3 plot , while low in (NH4)2SO4 plot.

• Korean Journal of Agricultural Science
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• v.9 no.2
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• pp.453-460
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• 1982

In order to investigate the effect of $AgNO_3$ pretreatment on reducing $SO_2$ injury in leaves of Forsythia koreana, changes of pH, chlorophyll content, peroxidase activity, sulfur content, and stomatal behaviour in leaves were examined. 1. $AgNO_3$ sprayed at 200 ppm or above increased black spot development in lower epidermis of leaves. But pretreatment with 100 ppm $AgNO_3$ significantly reduced de foliation and visible injury rate of leaves exposed to $SO_2$. 2. $AgNO_3$ pretreatment prevented lowering pH and decreasing chlorophyll content induced by $SO_2$ injury in leaves. But both $AgNO_3$ pretreatment and $SO_2$ exposure increased peroxidase activity in leaves. 3. $AgNO_3$ pretreatment did not affect reducing $SO_2$ absorption and stomatal opening in leaves exposed to $SO_2$.

• Korean Journal of Materials Research
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• v.19 no.7
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• pp.403-406
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• 2009

The friction characteristics of automotive brake friction materials that contained different ceramic content were investigated. Several kinds of raw materials, such as resin-based binder, reinforcing fiber, friction restraint, abrasive, and filling materials were mixed, pressed, and heated in order to make the brake friction materials. The contents of SiC and $BaSO_4$ changed from 5 vol% to 20 vol%, respectively. In addition to this, the content of $Al_2O_3$ adjusted from 1 vol% to 16 vol%. The surface morphology of the SiC containing sample appeared rough while more debris was observed when the contents of SiC increased. This implies that the SiC containing brake composite was not adequate for the automobile. However, the relatively smooth surface was observed in samples that contained the $Al_2O_3$. But the roughness was low with a content of 11 vol% $Al_2O_3$ compared to the other samples. This is consistent with the abrasive properties of the samples. In the case of $BaSO_4$ containing samples, the smoothes surface was observed in the contents of 15 vol% $BaSO_4$. Thus, it was concluded that the 11 vol% $Al_2O_3$ and 15 vol% $BaSO_4$ containing composite would be the optimum content for the brake composite. Similar to the results of the surface morphology, the abrasion resistance consistently decreased when the content of SiC increased. On the contrary, the sample that contained 11 vol% $Al_2O_3$ and 15 vol% $BaSO_4$ showed the highest abrasion resistance compared to the other samples.

• Journal of Korean Society of Forest Science
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• v.77 no.2
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• pp.223-228
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• 1988

To select $SO_2$-resistant tree species, leaf disks of 6mm in diameter, cut from the leaves of 6 species (Wistaria floribunda, Magnolia obovata, Rosa multiflora, Liriodendron tulipifera, Robinia pseudo-acacia and Acer palmatum) were floated on 25ml of testing medium and placed on laboratory under fluorescent lamp (1,500 Lux) for 20 hours. Chlorophyll content and acidity of the testing medium were measured. Testing medium was prepared by diluting $H_2SO_4$, $H_2SO_3$ and $Na_2SO_4$ with distilled water for various stoichiometric $SO_2$ concentrations, 0, 25, 50, 100 and 250 ppm. Total chlorophyll content was more decreased after treatment than before treatment, and was decreased more severely in $H_2SO_3$ sources, followed by $H_2SO_4$ and $Na_2SO_4$, sources. Decreasing rate of total chlorophyll content was generally large in Acer palmatum. Magnolia obovata and Wistaria floribunda, and was relatively small in Rosa multiflora, Liriodendron tulipifera and Robinia pseudo-acacia. Decreasing rate of chlorophyll content may be useful index for judging susceptifility of the leaf to $SO_2$. The acidity of the testing medium was generally decreased after treatment, and it means that cell leakage was occurred during treatment. The differences in medium acidity between before and after treatment may be poot index for susceptibility of the leaf to $SO_2$ owing to the difference among tree species in development of leaf mesophyll, acidity maintaining mechanism and butter capacity of the leaf tissue.

• Journal of the Korean Ceramic Society
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• v.22 no.2
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• pp.25-32
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• 1985

Effect of alkali $SO_3$ and $C_2S$ content and cooling condition of clinker on the formation of unstable alkali and cooling condition of clinker on the formation of unstable alkali was investigated. As a result alkali and $SO_3$ content of clinker were the main factors of unstable alkali formation and equation (7) in which the two factors were the variables showed a good agreement with the observed results. Water soluble alkali content of sulphate was decreased with increase of $C_2S$ content of clinker resulted by the increase of solid solution rate of alkali to clinker minerals. But change of unsatble alkali content accordint to the increase of $C_2S$ content was slight. A increasing tendency of ignition loss of clinker with increase of unstable alkali content was found.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.8
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• pp.1116-1122
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• 2015

This study aimed to investigate the effect of sunflower seeds, either as whole or as oil, on rumen fermentation, milk production, milk composition and fatty acids profile in dairy goats. Fifteen lactating Damascus goats were divided randomly into three groups (n = 5) fed a basal diet of concentrate feed mixture and fresh Trifolium alexandrinum at 50:50 on dry matter basis (Control) in addition to 50 g/head/d sunflower seeds whole (SS) or 20 mL/head/d sunflower seeds oil (SO) in a complete randomized design. Milk was sampled every two weeks during 90 days of experimental period for chemical analysis and rumen was sampled at 30, 60, and 90 days of the experiment for ruminal pH, volatile fatty acids (tVFA), and ammonia-N determination. Addition of SO decreased (p = 0.017) ruminal pH, whereas SO and SS increased tVFA (p<0.001) and acetate (p = 0.034) concentrations. Serum glucose increased (p = 0.013) in SO and SS goats vs Control. The SO and SS treated goats had improved milk yield (p = 0.007) and milk fat content (p = 0.002). Moreover, SO increased milk lactose content (p = 0.048) and feed efficiency (p = 0.046) compared to Control. Both of SS and SO increased (p<0.05) milk unsaturated fatty acids content specially conjugated linolenic acid (CLA) vs Control. Addition of SS and SO increased (p = 0. 021) C18:3N3 fatty acid compared to Control diet. Data suggested that addition of either SS or SO to lactating goats ration had beneficial effects on milk yield and milk composition with enhancing milk content of healthy fatty acids (CLA and omega 3), without detrimental effects on animal performance.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.103-106
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• 2008

A broiler experiment was conducted to compare the effects of supplementary iron sources and levels on the iron content of broiler meat. Two hundred and fifty hatched Ross broiler chickens were randomly assigned to 5 dietary treatments. Each treatment had 5 replicates of 10 birds (5 males and 5 females). Birds were housed in raised floor batteries and fed traditional broiler diets ad libitum for 5 weeks. Dietary treatments were as follows: Control, Fe-Met 100 (100 ppm iron as Fe-methionine), Fe-Met 200, $FeSO_4$ 100 (100 ppm iron as $FeSO_4{\cdot}7H_2O$) and $FeSO_4\;200$. There were no significant differences among treatments in parameters related to production performance. Liver contained approximately 10 times more iron than the leg muscle which contained approximately 3 times more iron than either breast muscle or wing muscle. Significant differences in iron content in the broiler meat were observed. In the breast meat, Fe-Met treatments were significantly (p<0.05) higher than other treatments in iron content. In the leg meat, Fe-Met treatments and $FeSO_4\;200$ treatment were significantly higher than the control in iron content. In the wing muscle, Fe-Met 200 treatment was significantly higher than other treatments in iron content. Iron content in the liver was significantly influenced by source and supplementation level of iron. Fe-Met treatments were higher than $FeSO_4$ treatments and 200 ppm treatments were higher than 100 ppm treatments in iron content in the liver. It is concluded that iron-methionine chelate is more efficient than iron sulfate and 200 ppm iron supplementation as Fe-Met is recommended for maximum iron enrichment in broiler meat.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1160-1164
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• 2013

The solid super acid catalyst $SO{_4}^{2-}$/$ZrO_2$ was prepared by impregnation method using $ZrO_2$ as the catalyst support. Catalyst forming was taken into consideration in order to separate catalyst from the mixture of cellulose acetate propionate (CAP). $Al_2O_3$ and sesbania gum powder were selected as binding agent and auxiliary agent respectively. The catalytic properties were evaluated through esterification of cellulose with acetic anhydride, propionic anhydride and characterized by XRD, FTIR and $NH_3$-TPD. In this paper, the effects of concentration of $H_2SO_4$ impregnated, calcination temperature, esterification temperature and esterification time on the yield, acyl content and viscosity of CAP were investigated. The results showed that $SO{_4}^{2-}/ZrO_2$ successfully catalyzed CAP synthesis over catalysts impregnated in 0.75 mol/L $H_2SO_4$ and calcined at $500^{\circ}C$. The yield, acetyl content and propionyl content of CAP reached the maximum value of 105.3%, 29.9% and 25.8% reacted at $50^{\circ}C$ for 8 h.

• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.46-51
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• 1993

In order to survery the risk of air-borne lead to human, the relation between air-borne lead level and blood lead level was examined by using of the kinetic model and statistical model. The results of this survey were as follows: 1. The pathways of lead intake were food and water, mainly. 2. Though blood lead level of Korean urbanire was higher than that of American or Japanese, it was not so severe as to influence human health. 3. The lead content in food and water was high, and so it is needed to confirm the cause of high content was whether second contamination by air pollution or not.