• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.1-8
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• 2023

In this study, to reduce CO₂ emission in the cement manufacturing process, we evaluated the limestone that is used as a raw material for cement, substituted with steel slag by the various substituted levels. Based on the chemical composition of each raw materials including limestone, and blast furnace slow cooling slag, converter slag, and KR slag as an alternative raw material, we simulated the optimal cement raw mixture by the substitution levels of limestone. Test results indicated that the steel slags contain a certain level of CaO that can be used as alternative decarbonated raw materials, and it has enough to partially reduce the amount of limestonem. And we estimated the maximum usable levels of each raw material. In particular, it was confirmed that by using a mixture of these raw materials rather than using them one by one, the effect of reducing limestone was increased and CO₂ emission from the cement manufacturing process could be reduced.

• 보일러설비
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• s.64
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• pp.124-129
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• 1999

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.113-113
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• 2010

유비쿼터스 시대를 맞이하여 현재의 전자제품은 초고주파 환경에서의 소형화된 마이크로파 소자를 요구하고 있다. 마이크로파 대역에서 세라믹 소재는 대부분의 폴리머 소재에 비해 낮은 유전손실 값을 보이고 있어 향후 확대되는 고주파화에 적합한 소재로 평가되고 있다. 하지만 세라믹 재료는 깨지기 쉬운 특성을 가지고 있어 공정 및 취급이 어려우며 높은 소결온도를 가지고 있어 융점이 낮은 재료와의 집적화에 있어서 난점을 가지고 있다. 이를 위해 본 연구실에서는 실온에서 세라믹을 비롯한 금속 및 폴리머 재료의 치밀한 코팅막의 성막 및 이종 접합이 가능한 Aerosol Deposition (AD 법)에 주목하였고 마이크로파 소자 제작 공정으로서 AD 법의 응용 가능성을 연구하였다. 마이크로파 소자의 기판으로서는 AD 법을 이용하여 유전손실이 낮고 플렉서블한 $Al_2O_3$-PTFE 혼합 기판을 제작하고 적용하였다. 금속 선로 패터닝 제작 공정으로는 도금법이 대표적이지만 고비용 및 복잡한 공정 절차, 폐화학용액으로 인한 환경문제 등의 단점을 지니고 있어 이를 대체하는 금속 선로 패터닝 공정이 절실히 요구되고 있다. 이를 위해 본 연구에서는 AD 법을 이용하여 금속 필름을 제작하고 대체 공정으로서의 가능성을 확인하였다. 하지만 AD 법을 이용한 세라믹 필름 제작에 관한 연구는 크게 활성화되어 있는 반면에 금속 필름의 제작, 특성 측정 및 개선에 관한 연구는 그에 비해 미비한 수준이다. 이를 위해 이번 연구에서는 AD 법을 이용하여 금속 필름을 성막 시에 영향을 미치는 요인을 고찰하였으며 또한 마이크로파 소자의 도체 손실에 크게 관계되는 금속 필름의 비저항 특성의 측정 및 개선에 관한 연구를 수행하였다. 이를 위해 본 연구에서는 정전장 시뮬레이션을 활용하여 AD 법으로 성막된 금속 필름의 정밀한 비저항 측정에 관한 연구방법을 마련하고 후열처리를 통한 비저항 특성을 개선시키는 연구를 진행하였다.

• Clean Technology
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• v.11 no.3
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• pp.129-139
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• 2005

Fluoride-type cleaning agents such as TFEA (2,2,2-trifluoroethanol) and HFE (hydrofluoroether) are noticed to be next generation cleaning agents alternative to CFCs since they do not destruct ozones in the stratosphere due to no containment of chloride in the molecule, have lower global warming potential compared to HFCs and HCFCs, and are thermally stable compounds. Thus, the physical properties and cleaning agents were measured and compared with those of CFC-113, 1,1,1-TCE and HCFC-141b which are ozone destruction substances. They were also compared and evaluated with those of IPA and methanol which are currently employing as alternative cleaning agents. And TFEA-based cleaning agents consisted of TFEA and alcohols or HFEs were formulated, their physical properties and cleaning abilities were measured and their utilization as alternative cleaning agents was evaluated. As a result, TFEA and HFEs have lower cleaning ability for their removal of various soils compared to chloride-type cleaning agents, but theyshow excellent cleaning ability for Fluoride-type soils. And it is observed that the formulated cleaning agents of TFEA and alcohols or HFEs caused to increase cleaning ability of flux and unsoluble cutting oil more than 100% compared to their individual component. Therefore, the fluoride-type cleaning agents are expected to be utilized for development of environmental-friendly non aqueous cleaning agents with excellent cleaning ability if they are formulated with proper solvents or additives.

• Environmental and Resource Economics Review
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• v.13 no.4
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• pp.593-619
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• 2004

This study analyzes the interfuel substitution of energy demand in Korean manufacturing sector using static and dynamic linear logit models. For the period of 1981~2002, this study uses petroleum, electricity, natural gas and coal as energy sources. According to the empirical results, firstly, the own-price elasticity of coal has been increased steadily even though its elasticity is smallest compared with those of other energy sources. On the other hand, price elasticity of natural gas is largest, but its value has been decreased after 1997. Price elasticities of petroleum and electricity are very stable over the sample period. One of the main features in trends of interfuel substitution is as follows. Substitution effect of a change in price of natural gas on both petroleum and coal has been increased especially after 1997. The implication of the empirical results is summarized as follows: First, the fact of inelastic own-price elasticity of petroleum implies that the dependency of Korean manufacturing sector on petroleum and coal will be persistent even in a sharp fluctuation of petroleum price. Second, the effects of price increase in natural gas on demand for petroleum and coal are very significant. Thus, price decline of natural gas rather than price declines of coal and petroleum could be more effective as an energy price policy for the reduction of $CO_2$ emission. The assessment on this implication will remain for future researches.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.1
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• pp.44-49
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• 2020

This study was conducted to investigate the possibility of replacing imported Timothy hay (TH) with domestic Italian ryegrass silage (IRGS) as a horse feed considering feed quality, nutrient digestibility and feed price. Two experimental diets (TH and IRGS) were fed to six-headed Thoroughbred (body weight, 475.7±33.3kg) of the Korea Racing Authority of Wondang Stud Farm. The 3 head animals were assigned to Control group (TH) and Treatment group (IRGS), respectively. The nutrient digestibility was determined by the total collection method. IRGS is enough for using as a horse feed because its Relative feed value(RFV) was higher than TH and its fermentation quality is suitable for horses. Although no difference was observed in nutrient digestibility, Total digestible nutrients(TDN), and Digestible energy(DE) between Control and Treatment group (p>0.05), the fact that price of IRGS was much lower (53.7~62.4%) than that of TH indicates IRGS has competitive advantage over TH as a horse forage feed. The present study indicates that IRGS can be fully replaced with TH due to its superior economic value even though the similarity of its nutrient digestibility, TDN, and DE to TH.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.122-127
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• 2003

A surimi like material was made from fresh pig hearts and used to manufacture emulsion-type sausages for the improvement of quality characteristics. The heart muscles were diced and frozen at -60$^{\circ}C$ until processed. Then, the frozen diced heart muscles were thawed, chopped, filtered, and washed to extract myofibrillar proteins. The residue was centrifuged to take a surimi-like material. Emulsion-type sausages were made different levels of surimi-like material(5∼15%) and compared to the control. Cooking loss(CL, %) and water-holding capacity (WHC, %) were measured on raw meat batter, whereas shear force, hardness, color and panel test were measured after cooking. The addition of the surimi-like material up to 15% level in the sausage formulation reduced CL and increased WHC, as compared to the control. Shear force and hardness values of the control had the highest value, however sausages containing 15% surimi-like material had the lowest value(p<0.05). Increased surimi-like material became darker in color. Although no differences in panel scores of flavor and off-flavor were observed, panellists prefer to select sausages having 15% surimi-like material(p<0.05). These results indicated that a surimi-like material, which was a myofibrillar protein extracted from pig hearts, could be used to manufacture emulsion-type sausage up to 15% to improve cooking yield and textural characteristics without color and flavor defects.

• Journal of Aquaculture
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• v.10 no.2
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• pp.143-151
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• 1997

A six week feeding trial was conducted to determine the amount of fish meal analog (FMA) that can be replacing fish meal protein (FM) in Korean Rockfish. Seven experimental diets were formulated on isonitrogenous 52% crude protein and isocaloric basic 16.8KJ/g diet. Also, foreign commercial fish meal analog (CFMA) and attractants (ATT) were tested in this experiment. Percentage of the graded level of replacement of FM by FMA/CFMA on the basis of crude protein were as following : Diet 1, 100%FM ; Diet by 2, 60%FM : 40% CFMA ; Diet 3, 60%FM : 40$ CFMA+ATT ; Diet 4, 80%FM : 20%FMA ; Diet 5, 80%FM : 20% FMA+ATT ; Diet 6, 60%FM : 40%FMA+ATT ; Diet 7, 40%FM : 60% FMA+ATT. The FMA was made by mixing six animal protein source such as th blood meal, squid liver powder, meat and bond meal, leather meal, feather meal, poultry by-product and 3 essential amino acids (Met, Lys, Ile). Weight gain, feed efficiency, specific growth rate and protein efficiency ratio of fish fed diets 4, 5 and 6 were not significantly different (P>0.05) from those of fish fed the control (100% FM), while those of fish fed diets 2 and 3 were significantly lower (P<0.05) than those of fish fed the diet 6. There was no significant ATT effects in this study (P>0.05). Significant differences were found in hepatosomatic index, hemoglobin and condition factor. Therefore, these, results indicated that FMA can be used up to 40% as a substitute of fish meal protein in Korean Rockfish diets.

• Journal of Aquaculture
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• v.11 no.4
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• pp.487-493
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• 1998

This study was conducted to investgate the effect of fish meal analogue (FMA) on the growth of Israeli carp, Cyprinus carpio averageing 43g. Leather meal, meat and bone meal, feather meal, squid liver powder, poultry by-product and blood meal were used for ingredient of FMA. Four experimantal diets were formulated to contain 36% crude protein and 15.4 kJ available enery g-1. The percentage of follows ; Diet 1, 100% 3, 60% WFM + 40% FMA (40% FMA) ; Diet 4, 40% WFM + 60% FMA (60% FMA). In this expriment, fingerling Israeli carp averaging 43 g were assigned to each diet treatment. When the experiment was terminated, weigth gain (WG), feed conversion (FC), specific growth rate (SGR) and protein efficiency ratio (PER) were measured respectively. In the experiment, WG, FC, SGR and PER of Diet 2 were not significantly different from those of the control diet (P0.05). And WG, FC and SGR of Diet 3 were not significantly of the control Diet. In Diet 4, WG, FC and PER were not significantly different from those of the control Diet, but SGR was lower than that fo the control Diet. According to the results from this study, it might be possible to replace fish meal protein by FMA up to 60% in fingerling Israeli carp diets.

• Journal of Mushroom
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• v.20 no.4
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• pp.270-273
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• 2022

The present study investigated the optimum additive ratio of wheat straw pellet as a substitute for beet pulp during oyster mushroom cultivation. The chemical properties across treatments were pH of 4.8-5.5, total carbon content of 45.9-46.5%, total nitrogen content of 1.5-1.7%, and carbon-to-nitrogen ratio of 27.8-31.0. Mycelial growth was the fastest in a medium containing 20% wheat straw pellet (at 88.2 mm in 'Heuktari' and 70.3-79.6 mm in 'Suhan-1Ho'); however, there were no significant differences in mycelial density among the treatments. The characteristics of fruiting bodies by variety were as follows. In 'Heuktari', the valid stipe number per bottle (1,100 cc) was 22.5 and yield was 177.1 g/1,100 cc in the mixed medium containing 10% wheat straw pellet, with the values being comparable to those of controls. In 'Suhan-1Ho', the valid stipe number per bottle (1,100 cc) was 14.0 and yield was 151.2 g/1,100 cc in the mixed medium containing 10% wheat straw pellet, with the values being comparable to those of controls.