• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1743-1751
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• 2014

It is well known that latex modification can lead to enhancement compressive and flexural performance, tensile bond strength, chloride penetration resistance and freezing-thawing resistance for concrete. For these, many studies for LMC pavement have been widely conducted more than those for conventional pavement concrete. However, due to several problems such as noise and construction cost, new approaches for LMC have been executed to improve the performance of LMC. Recently, Remicon LMC was developed in order to solve the problems of LMC. In this study, the durability of Remcion LMC was compared with latex and mineral additive mixing ratio. From the results, when latex and mineral additive were mixed in Remicon LMC, compressive, flexural and bond strength were satisfied with Korea Highway Construction Guide Specification. And, it showed that the qualitative effect of latex and mineral additive mixing ratio on the durability of Remicon LMC was investigated experimentally. Also, the latex mixed in Remicon LMC must be at least 8%, in order to ensure the durability equivalent or higher than conventional LMC.

• 농업기술회보
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• v.47 no.5
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• pp.40-41
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• 2010

큰 일교차는 가축면역력 약화를 부른다. 낮과 밤의 일교차 약 $10^{\circ}C$ 전후의 환절기에는 면역력이 약한 어린 가축은 환경의 변화에 따른 대사불균형으로 질병 발생률이 높아진다. 가축에게 환경 스트레스를 낮춰주기 위해 아침 저녁으로 바깥의 찬공기에 노출되지 않도록 차단해야 하고 야간에는 축사보온, 낮에는 환기가 충분히 이루어지도록 해야 한다. 또한 양질의 사료공급은 물론 비타민, 광물질 등의 첨가제를 적절히 배합해 급여하고 호흡기 질병 및 설사병 등의 백신을 적기에 접종해 면역능력을 가질 수 있도록 해야 한다.

• Journal of the korean veterinary medical association
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• v.27 no.8
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• pp.470-482
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• 1991

가축의 생산성을 향상시키기 위해 다양한 성장촉진물질이 사용되고 있다. 본고에서는 이러 한 목적으로 사용되고 있는 여러 제제의 효과와 작용기전 그리고 그 위해성에 대해 간단하게 검토를 하여 보았다. 항생물질은 여러 축종에 대한 성장촉진 목적으로 가장 많이 사용되고 있는 제제이나 잔류독성 및 내성에 의한 공중위생상 위해성 때문에 안전한 대체성장촉진물질에 대한 요구는 계속 증대되고 있다. 광물질 첨가제, 효모제, 효소제, 유기산제제, 생균제, 흐르몬제 등에 대해서 간단히 살펴보았으며 특히 최근 관심이 고조되고 있는 성장호르몬과 아드레날린성 베타 수용체 작용약에 대해 약리학적 평가를 시도하였다. 일찌기 스위스의 Paracelsus(1493$\~$1541)는 '모든 물질은 독물이며 다만 용량이 문제일뿐 독성이 없는 물질은 없다'라고 하였듯이 새로운 물질의 사용은 항상 그에 수반하는 부작용이 있을 것이므로 이에 대한 깊은 관심을 가져 올바른 사용법을 확립하는데 최선을 다하여야 할 것이다.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.229-238
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• 2023

Bentonite is a type of rock that has been used as a traditional mineral medicine. It has a variety of pharmacological activities, and is used in traditional Korean medicine to treat jaundice, diarrhea, and hemostasis. In modern medicine, it is used as a raw material and additive for medicines such as antacids, gastrointestinal protective agents, and laxatives. Bentonite produced in Korea was produced through diagenesis or hydrothermal alteration of tertiary volcanic debris distributed in the Pohang and Gyeongju areas. It is mainly used for industrial purposes such as papermaking, paint, civil engineering, casting, and animal feed. Recently, technology is being developed to use it in cosmetics and pharmaceuticals. In this study, the geochemical characteristics of bentonite were identified by analyzing the main components and trace elements of 40 and 21 types of bentonite produced in the Gampo Gyeongju and Yeonil Pohang area. Also it were classifed by formation envrionment of bentonite deposits in the Gampo and Yeonil. As a result of the study, bentonite from the reserch area may be cased by argillic alteraton that alkali elements are removed form basaltic rocks by hydrothermal fluids and AI-CCPI alteration indices wrere also indentified argillic alteraton. It was found that there is a correlation between the behavior characteristics of heavy metal elements (P b, Cr, As) and the hydrothermal alteration of bentonite in the reserch area.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.6
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• pp.90-98
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• 2002

Recently the use of the antiwashout underwater concrete with the antiwashout admixture is increased considerably. Antiwashout underwater concrete is quite different in concept from conventional underwater concrete. By mixing an antiwashout admixture with concrete, the viscosity of the concrete is increased and its resistance to segregation under the washing action of water is enhanced. The aim of this research is to evaluate the fundamental characteristics and permeability of antiwashout underwater concrete with fly ash and blast-furnace slag. Test Results of antiwashout underwater concrete with fly ash and blast-furnace slag fluence can provide its excellent fundamental characteristics and resistance of permeability.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.251-262
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• 2014

Inorganic binders were studied in order to apply a conservation material for stone monument. A pure inorganic binder and 3 species of inorganic binder which contain additives on the basis of a pure inorganic binder were selected as test samples. Through the application of inorganic binders on Geochang granite investigate their influences on stone. pH 4.0 and 5.6 acid solution, respectively were manufactured on the basis of the acidity of domestic rainfall. Alkaline water with pH 8.0 and deionized water with pH 6.85 were prepared as control group. Changes in weights of inorganic binders were not definite according to the acidity of water while weight losses in inorganic binder type were greater after reaction with the water. The compressive strengths of pure inorganic binder was largest before the test but its decrease rate were larger after reaction with the water. Water absorption rate of inorganic binders are 6.72 to $12.44kg/m^2{\cdot}t^{1/2}$ after reaction with the water. Such high absorption was considered that it forced water to move deep into inorganic binder and made the components of inorganic binder dissolve. Acidities of the water of pH 4.0, 5.6, 6.85 and 8.0, respectively were changed to pH 9.0-10.0 after reaction with the inorganic binders. Ion concentrations in the water changed after reaction with the inorganic binders and $Mg^{2+}$, and $K^+$ significantly increased, dissolved from the binder. The high concentration of ions detected showed that the binder reacted with water and formed white salts with high solubility such as $MgSO_4{\cdot}nH_2O$, $KNO_3$. Ion concentrations significantly decreased from the binder after treatment with consolidant and water repellent.

• Korean Journal of Poultry Science
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• v.33 no.4
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• pp.263-271
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• 2006

This experiment was conducted to evaluate the effects of dietary Hwangto on growth performance and body composition in broiler chicks. A total of 216 one-day old 'Ross' broilers were assigned to 6 treatments in a completely randomized design. The six dietary treaoents were control no Hwangto added and diets containing 0.5, 1.0, 2.0, 4.0 and 8.0% of Hwangto supplementation. The weight gain of broilers tended to reduce with increasing level of Hwangto. However, there were no significant differences in feed intake and feed conversion ratio of broilers fed control and diets containing different level of Hwangto supplementation (P>0.05). There were no significant differences in TBA value of meat from broilers fed control and Hwangto supplemented diets (P>0.05). The meat cholesterol content was significantly lower in Hwangto treatment than of the control (P>.0.05). $NH_3$ concentration in feces was reduced in all Hwangto treatments (P<0.05). The Mg and Mn concentrations of meat we.e significantly higher in 8.0% Hwangto treatment than that of the control (P<0.05). The large intestine weight was significantly reduced in 2.0, 4.0 and 8.0% treatments (P<0.05).

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.737-742
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• 2005

Rheological properties of ordinary portland cement (OPC) containing metakaoline (MK), granulated blast furnace slag (GBS) and polycarboxylate type superplasticizer (PCA) were investigated using a mini-slump test, sedimentation test and viscometer. Fluidity of cement pastes containing MK (OPC-MK, OPC-MK-GBS systems) with PCA were higher than those of the cement pastes without MK(OPC, OPC-GBS systems). Colloid suspensions with $0.1\%$ PCA were changed from stable sedimentation behaviors to flocculation behaviors in the OPC-MK, OPC-GBS and OPC-MK-GBS systems. The colloid suspensions showed stable sedimentation behaviors with PCA greater than $0.2\%$. The OPC system showed shear thinning behavior. However, the other systems showed weak shear thinning behaviors with PCA. Rheological properties of cement pastes were improved when MK and GBS were contained together. The rheological properties of OPC-MK, OPC-GBS and OPC-MK-GBS systems were improved by PCA added greater than $0.2\%$.

• Journal of the Mineralogical Society of Korea
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• v.31 no.1
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• pp.47-55
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• 2018

Talc, hydrous magnesium phyllosilicate, is one of the most popular industrial minerals due to their chemical stability and adsorptivity. While micro-sized talc has long been used as a filler and coating, nano-sized talc recently is attracting attention as additives for improving the stability of nanocomposites. In this study, we produced the nano-sized talc powder by mechanical method using high energy ball mill and investigated the changes in particle size and crystallinity with increasing milling time up to 720 minutes. X-ray diffraction results show that the peak width of talc gradually as the milling proceeded, and after 720 minutes of pulverization, the talc showed an amorphous-like X-ray diffraction pattern. Lase diffraction particle size analysis presents that particle size of talc which was ${\sim}12{\mu}m$ decreased to ${\sim}0.45{\mu}m$ as the milling progressed, but no significant reduction of particle size was observed even after grinding for 120 minutes or more. BET specific surface area, however, steadily increases up to the milling time of 720 minutes, indicating that the particle size and morphology change steadily as the milling progressed. Scanning electron microscope and transmission electron microscope images shows that layered particles of about 100 to 300 nm was aggregated as micro-sized particles after pulverization for 720 minutes. As the grinding time increases, the particle size and morphology of talc continuously change, but the nano-sized talc particles form micro sized agglomerates. These results suggest that there is a critical size along the a, b axes in which the size of plates is reduced even though the grinding proceeds, and the reduction of plate thickness along the c axis leads the increase in specific surface area with further grinding. This study could enhance the understanding of the mechanism of the formation of nano-sized talc by mechanical grinding.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.25-32
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• 2006

This experiment was conducted to investigate the effects of dietary Vita2000 on growth performances and immune response in broiler chickens. One-day-old male chicks were fed diets containing 0, 0.5 and 1% Vita2000 (with or without antibiotics) for 5 wks. There were no significant differences in daily weight gain among the treatments, but feed intake in 1% Vita2000 groups (T3 and T4) were significantly lower than control (P<0.05). The relative abdominal fat weight and the level of crude fat in leg meat on groups fed diets containing 1% Vita2000 (T3 and T4) were significantly decreased as compared to those of control (P<0.05). The content of cholesterol in leg meat was not affect by dietary treatment. The intestinal total microbes, Coli form, Lactic acid bacteria and Salmonella spp. from bird fed 1% Vita2000 diets was significantly reduced compared to those of control. The production of IB antibody in chicks fed diet containing 0.5% Vita2000 was significantly higher than that of control groups. The overall results indicate that dietary Vita2000 may be a valuable alternative to antibiotics for optimizing growth performances, particularly for reducing the abdominal fat of broiler chicks.