The issue surrounding the problem of air pollution arising from rapid industrialization is one that is being continuously raised for discussion among the public, and concerns about indoor air quality have emerged both at home and abroad due to the longer periods of time spent indoors in modern times. Various studies are being conducted to solve this problem, and photocatalysts are also being studied as a solution. Accordingly, this research sought to verify the performance of reducing indoor pollutants by applying photocatalysts to building materials. As a result of evaluating the indoor pollutant reduction performance, it was confirmed that acetaldehyde was reduced by about 31%, toluene 29%, and total volatile compounds by 11%, and adhesion strength, an important factor regarding finishing material, was also enhanced 1.3 times or more based on Korean Industrial Standards. From these results, it is believed that indoor air pollution can be lowered to a certain extent through building materials using photocatalysts, and, therefore, research on long-term performance verification and evaluation methods should be continuously conducted and pursued in the future in relation to photocatalysts.

In this work, ultra-fine calcium oxide (CaO) powder derived from eggshells is used as the starting material to synthesize mineral trioxide aggregate (MTA). The prepared CaO powder is confirmed to have an average particle size of 500 nm. MTAs are synthesized with three types of fine CaO-based powders, namely, tricalcium silicate (C3S), dicalcium silicate (C2S), and tricalcium aluminate (C3A). The synthesis behavior of C3S, C2S and C3A with ultra-fine CaO powder and the effects of C3A content and curing time on the properties of MTA are investigated. The characteristics of the synthesized MTA powders are examined by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), and a universal testing machine (UTM). The microstructure and compressive strength characteristics of the synthesized MTA powders are strongly dependent on the C3A wt.% and curing time. Furthermore, MTA with 5 wt.% C3A is found to increase the compressive strength and shorten the curing time.

본 연구는 섬초 분말 1%, 3%, 5%, 7% 첨가비율에 따른 식빵의 품질 특성을 연구하였다. 반죽의 pH는 첨가량이 증가할수록 낮아졌으며, 7% 첨가에서 낮게 나타났다. 반죽의 발효 팽창력은 1차 발효와 2차 발효에서 첨가량이 증가할수록 낮아졌으며, 첨가량에 따라 반죽의 발효시간이 지날수록 감소하는 것으로 나타났다. 식빵의 수분함량은 첨가량이 증가할수록 낮아졌으며, 식빵의 부피는 1% 첨가> 3% 첨가> 5% 첨가> 7% 첨가 순으로 나타났다. 비용적은 첨가량이 증가할수록 제품의 부피는 낮게 나타났으며, 비용적이 낮을수록 부피는 감소하였다. 내부색도는 첨가량이 증가할수록 명도, 적색도는 감소하였으며, 황색도는 증가하는 걸로 나타났다. 총 구성아미노산 함량은 첨가량이 증가할수록 높게 나타났으며, glutamic acid가 높게 나타났다. 총 유리아미노산 함량은 첨가량이 증가할수록 높게 나타났으며, 5% 첨가와 7% 첨가에서 cystine이 가장 높게 나타났다. 식빵의 조직감은 대조구에 비하여 탄력성과 응집성이 낮게 나타났으며, 씹힘성, 부서짐성, 경도는 대조구에 비하여 높게 나타났다. 부착성은 7% 첨가에서 나타났다.

The purpose of this study was to investigate the rheological characteristics of medium wheat flour mixed with bamboo leaf and lotus leaf powders. Rheological properties of the mixed flours were tested based on falling number, color, RVA, farinogram, and rheofermentometer analyses. Falling numbers increased with addition of bamboo leaf and lotus leaf powders. The L values of all mixed flours were less than that of control. The 1% mixed flour sample containing bamboo leaf and lotus leaf powders was not significantly different from 3% mixed flour. The a values of the mixed flour decreased as bamboo and lotus powders increased, whereas b values increased. Addition of bamboo leaf and lotus leaf powders to flour reduced peak viscosity, holding strength, and final viscosity. The set back values of mixed wheat flour containing bamboo leaf powder were lower than those of mixed wheat flour containing lotus leaf powder, suggesting that bamboo leaf powder suppressed retrogradation of flour compared to lotus leaf powder. In the farinogram, the water absorption and consistency of the flours containing bamboo and lotus leaf powders increased, whereas development time and stability decreased. The fermentation time of dough with lotus leaf powder was less than that of dough with bamboo leaf powder.

In this study, nanocrystalline Cu-Ni bulk materials with various compositions were cold compacted by a shock compaction method using a single-stage gas gun system. Since the oxide layers on powder surface disturbs bonding between powder particles during the shock compaction process, each nanopowder was hydrogen-reduced to remove the oxide layers. X-ray peak analysis shows that hydrogen reduction successfully removed the oxide layers from the nano powders. For the shock compaction process, mixed powder samples with various compositions were prepared using a roller mixer. After the shock compaction process, the density of specimens increased up to 95% of the relative density. Longitudinal cross-sections of the shock compacted specimen demonstrates that a boundary between two powders are clearly distinguished and agglomerated powder particles remained in the compacted bulk. Internal crack tended to decrease with an increase in volumetric ratio of nano Cu powders in compacted bulk, showing that nano Cu powders has a higher coherency than nano Ni powders. On the other hand, hardness results are dominated by volume fraction of the nano Ni powder. The crystalline size of the shock compacted bulk materials was greatly reduced from the initial powder crystalline size since the shock wave severely deformed the powders.

본 연구는 혈압 강하, 비타민 B1의 활성화, 항암 효과, 노화방지 등에 탁월한 효과가 있다고 알려진 마늘의 활용도를 더욱 높이기 위하여 중력분에 수준별(1%, 3%, 5%) 마늘 분말을 첨가하여 물성 변화 및 마늘가루 첨가가 제면 적성에 미치는 영향을 실험하였다. 마늘 분말 첨가량을 달리하였을 때 호화도 변화를 측정한 결과, 마늘 분말 양이 증가하면 호화 개시온도가 높아졌으며, 최고 점도는 낮아졌다. 최고 점도와 최저 점도의 차이를 나타내는 breakdown 값도 낮아졌다. 또한 최종 점도도 약간 낮아지는 경향을 보였으며, 마늘 분말 첨가량이 증가하면 set back값은 감소하는 경향이었지만 노화를 억제할 정도는 아니었다. Farinogram의 consistency는 마늘 분말 첨가량이 많아질수록 높아졌고, 수분흡수율 또한 높아지는 경향을 보였다. 반죽형성시간은 길어졌으며 안정도는 낮아졌으며, 마늘 분말 첨가량이 많아질수록 time to breakdown 값이 급격하게 떨어졌다. Mechanical tolerance index 값이 마늘 분말 첨가 시료들의 경우 낮게 나타나, 마늘 분말을 첨가하면 반죽의 기계적 적성이 떨어진다는 것을 알 수 있었다. Farinogram quality number는 중력분 대조구에 비하여 마늘 분말 첨가구들은 첨가량이 많아질수록 그 수치가 떨어졌다. 그러나 1% 첨가구와 3% 첨가구 사이에서는 서로 간에 유의적인 차이를 보이지 않았다. Alveogram을 이용하여 글루텐 강도를 측정한 Pmax 값은 마늘분말 첨가량이 많아질수록 Pmax 값이 감소되었을 뿐만 아니라, 서로 간에 유의적인 차이를 보이지도 않았다. 팽창된 반죽이 터질 때까지의 신장성을 나타내는 L값은 마늘 분말 첨가량이 증가하면 감소하였다. 그러나 3% 첨가구와 5% 첨가구 사이에서 유의적인 차이는 나타나지 않았다. 팽창지표를 나타내는 G값 역시 마늘 분말 함량이 많아지면 G값은 낮아졌다. 하지만 3% 첨가구와 5% 첨가구 사이에서는 L값과 마찬가지로 유의적인 차이를 보이지 않았다. 변형 에너지 값인 W값도 마늘 분말 첨가량이 증가하면 W값은 감소하였으며, 특히 대조구에 비하여 마늘 분말 1% 첨가구는 급격하게 수치가 낮아졌다. 3% 첨가구와 5% 첨가구 사이에서는 유의적인 차이를 보이지 않았다.

This study investigated the effects of the diet with Cucurbita moschata (CM), adlay seed (AS), and Cudrania tricuspidata leaf (CTL) mixed-powder on the visceral fat, fecal amount, and serum lipid profiles in rats fed a high-fat diet (HFD). The mixed ratio of CM, AS, and CTL as a functional food ingredient was 1:1:1 on a weight basis. Male Sprague-Dawley rats were fed a high-fat diet (D12492; 45 kcal fat) for 5 weeks during the first phase. In the second phase, which lasted 5 weeks, the rats were divided into six experimental groups. The groups were: a high-fat diet group as a control during the 10 weeks of experimental period; and a high-fat diet with 5, 10, 15, 20, and 30% mixed powder supplement group. The adipose tissue (RFP, EFP) weights were significantly decreased in the 20% and 30% mixed powder supplement groups than in the HFD group (p<0.05). The fecal weight produced by the 15%, 20%, and 30% mixed powder supplement groups was significantly increased during the second phase compared to the first phase (p<0.05). In terms of serum lipids, TG (triglyceride) content was decreased in the 10% and 15% mixed-powder supplement groups. The blood glucose levels were significantly decreased in all experimental diet supplement groups than in the HFD group (p<0.05). The findings show that the high supplement groups could improve the visceral fat accumulation, fecal amount, and blood glucose content compared to the HFD group.

The electromagnetic wave absorption sheets were fabricated by mixing of nanocrystalline soft magnetic powder, charcoal powder and polymer based binder. The complex permittivity, complex permeability, and scattering parameter have been measured using a network analyzer in the frequency range of 10 MHz10 GHz. The results showed that complex permittivity of sheets was largely dependent on the frequency and the amount of charcoal powder : The permittivity was improved up to 100 MHz, however the value was decreased above 1 GHz. The power loss of electromagnetic wave absorption data showed almost the same tendency as the results of complex permittivity. However, the complex permeability was not largely affected by the frequency, and the values were decreased with the addition of charcoal powder. Based on the results, it can be summarized that the addition of charcoal powder was very effective to improve the EM wave absorption in the frequency range of 10 MHz1 GHz.

In this study, we attempted to develop a convenient aluminizing process, using Al-Ti mixed slurry as an aluminum source, to control the Al content of the aluminized layer as a result of a one-step process and can be widely adopted for coating complex-shaped components. The aluminizing process was carried out by the heat treatment on disc and rod shaped S45C steel substrates with Al-Ti mixed slurries that were composed of various mixed ratios (wt%) of Al and Ti powders. The surface of the resultant aluminized layer was relatively smooth with no obvious cracks. The aluminized layers mainly contain an Fe-Al compound as the bulk phase. However, the Al concentration and the thickness of the aluminized layer gradually decrease as the Ti proportion among Al-Ti mixed slurries increases. It has also been shown that the Al-Ti compound layer, which formed on the substrate during heat treatment, easily separates from the substrate. In addition, the incorporation of Ti into the substrate surface during heat treatment was not observed.

The electromagnetic (EM) wave absorption properties of the nanocrystalline powder mixed with 5 to 20 vol% of Ni-Zn ferrites has been investigated in a frequency range from 100MHz to 10GHz. Amorphous ribbons prepared by a planar flow casting process were pulverized and milled after annealing at 425 for 1 hour. The powder was mixed with a ferrite powder at various volume ratios to tape-cast into a 1.0mm thick sheet. Results showed that the EM wave absorption sheet with Ni-Zn ferrite powder reduced complex permittivity due to low dielectric constant of ferrite compared with nanocrystalline powder, while that with 5 vol% of ferrite showed relatively higher imaginary part of permeability. The sheet mixed with 5 vol% ferrite powder showed the best electromagnetic wave absorption properties at high frequency ranges, which resulted from the increased imaginary part of permeability due to reduced eddy current.

To investigate the effect of process parameters on selective laser sintering of Cu/polyamide mixed powder, Cu/polyamide mixed powder was sintered by selective laser with changing laser power and scanning speed. The properties of sintered body were evaluated by measuring the density and tensile strength, and analysis of XRD, FT-Raman and microstructure. With an increase in the laser power, the density and ultimate tensile strength of sintered Cu/polyamide body increase and then decrease. The maximum values of the density and ultimate tensile strength were decreased with increasing laser scanning speed. These changes were concerned with the difference of irradiation energy of laser into the powder layer. It was considered that the change of the mechanical property of the sintered body with irradiation energy of laser is due to the changes of amount of copper particle and property of polyamide.

The effect ofgas sintering atmosphere on the carbon content and mechanical properties during the metal injection molding process of carbonyl iron-nickel powder was studied. The carbon content of the specimen after debinding in the pureatmosphere appeared 0.78 wt%. After showing the maximum value of 1.48 wt.% in the debinding atmosphere of 10%gas mixture, the carbon content of the debinded specimen decreased gradually with increasing thecontent in thegas mixture. The carbon contents of the sintered specimen were 0.46~0.63wt% in Na gas atmosphere, while they appeared extremely low above 40%gas atmosphere. The relative sintered density increased abruptly from 88~90% to 93~96% with the addition of Ni, while the density nearly unchanged above 2% Ni addition. The sintered density increased with increasing the fraction ofgas mixture. Tensile strength and hardness increased, and elongation decreased with increasing carbon and Ni content. In spite of high carbon content of 0.63 wt%, the superior elongation value of 10% was shown.

The effect of the role of alloyed components on the densification of two kind of high speed steel (mixed and prealloyed powder), which were sintered at 1403~ 1573 K for 7.2 ks in vacuum, was investigated. The results obtained were as follows. (1) Without the presence of Vanadium (V), the relative density of sintered compacts (Ds) could not reached the density of 100% regardless of the. elements in the compacts. (2) The addition of V up to 2 mass% did not result In the complete densification when the carbon content was fixed at 2% in the compact. (3) With the fixed amount of V of 7%, Ds decreased with the increase of the carbon content. (4) The addition of mixed fine powder to the prealloyed powder in the range of 20 to 40% provided the complete densification and carbide panicles of 1~2 through the solid phase sintering. (5) The V element played important role in controlling the complete or incomplete densification of the sintered compacts in the alloyed component because of its formation of stable oxide and carbide as well as the low equilibrium pressure of CO gas.

This paper presents an experimental study investigating the bond characteristic of steel bars (D13, D16) on fluidity concrete mixed with recycled marble powder under tensile loads. Experimental results showed that average bond strengths of D13 series specimens and D13 series specimens were 18.00MPa and 15.67MPa respectively, and that specimen with the larger diameter of rebar that adhesion strength had the lower bond strength.

본 연구는 잡곡을 이용한 다양한 제품 개발 및 활용성 증대의 일환으로 혼합잡곡분말을 제조하고 이들의 영양성 및 기능성을 측정하였다. 혼합잡곡분말은 조단백질과 조지방의 함량이 높게 나타났다. 혼합잡곡 분말의 주요 유리당은 fructose, glucose, sucrose, maltose였으며, 혼합잡곡분말 B가 가장 높은 유리당 함량을, 혼합잡곡분말 D가 가장 높은 유리아미노산 함량을 나타냈다. 또한 주요 무기질은 칼륨(K), 마그네슘(Mg), 칼슘(Ca)으로 나타났다. 총 폴리페놀과 총 플라보노이드 함량은 29.27~52.94 mg/100 g, 2.53~4.94 mg/100 g 범위로 비율에 따라 미비한 차이를 나타내었으며, 혼합잡곡분말 F가 가장 높은 총 폴리페놀 및 총 플라보노이드 함량을 나타냈다. 혼합잡곡분말의 DPPH radical 소거능과 환원력은 혼합잡곡분말 C가, ABTS radical 소거능은 혼합잡곡분말 D가 가장 높은 활성을 보였으나 시료 C와 D의 유의적인 차이는 나타나지 않았다. 따라서 영양성과 기능성이 높은 혼합잡곡분말 제조를 위해서 시료 D와 같이 보리, 기장, 수수, 율무를 2:2:1:1의 비율로 혼합하는 것이 가장 바람직 할 것으로 판단된다.

라면 수프의 품질 안정화 기술을 개발하기 위하여 라면 수프의 주원료인 고추향미유가 첨가된 조제고춧가루를 에서 6주간 저장하면서 화학적 특성 변화를 조사하였다. 시료의 일반성분은 6주간 저장 후에도 크게 변화하지 않았고(p>0.05), pH 는 지속적으로 감소하였으며, 시료로부터 추출한 지질의 산가는 저장기간이 길어짐에 따라 증가하였다. ASTA 값과 CIE 값, CIE 값, 그리고 CIE 값 모두 저장기간이 길어짐에 따라 크게 감소하였다. 시료