Zinc oxide(ZnO) micro/nanocrystals are grown via thermal evaporation of ZnO powder mixed with Mn powder, which is used as a reducing agent. The ZnO/Mn powder mixture produces ZnO micro/nanocrystals with diverse morphologies such as rods, wires, belts, and spherical shapes. Rod-shaped ZnO micro/nanocrystals, which have an average diameter of 360 nm and an average length of about 12 μm, are fabricated at a temperature as low as 800 °C due to the reducibility of Mn. Wireand belt-like ZnO micro/nanocrystals with length of 3 μm are formed at 900 °C and 1,000 °C. When the growth temperature is 1,100 °C, spherical shaped ZnO crystals having a diameter of 150 nm are synthesized. X-ray diffraction patterns reveal that ZnO had hexagonal wurtzite crystal structure. A strong ultraviolet emission peak and a weak visible emission band are observed in the cathodoluminescence spectra of the rod- and wire-shaped ZnO crystals, while visible emission is detected for the spherical shaped ZnO crystals.

Generally, ceramic tiles for building construction are manufactured by dry forming process using granular powders prepared by spray drying process after mixing and grinding of mineral raw materials. In recent years, as the demand for large ceramic tiles with natural texture has increased, the development of granule powders with high packing ratio and excellent flowability has become more important. In this study, ceramic tile granule powders are coated with hydrophobically treated silica nanoparticles. The effects of hydrophobic silica coating on the flowability of granule powders and the strength of the green body are investigated in detail. Silica nanoparticles are hydrophobically treated with GPTMS(3-glycidoxypropyl trimethoxy silane), which is an epoxy-based silane coupling agent. As the coating concentration increases, the angle of repose and the compressibility decrease. The tap density and flowability index increase after silica coating treatment. These results indicate that hydrophobic treatment can improve the flowability of the granular powder, and prevent cracking of green body at high pressure molding.

The recent development of information and communication technologies brings new changes to automobile traffic systems. The most typical example is the advancement of dedicated short range communication(DSRC). DSRC mainly consists of an intelligent transportation system(ITS), an electronic toll collection system(ETCS) and an advanced traveler information system(ATIS). These wireless communications often cause unnecessary electromagnetic waves, and these electromagnetic waves, in turn, cause frequent system malfunction. To solve this problem, an absorber of electromagnetic waves is suggested. In this research, various materials, such as powdered metal and iron oxides, are used to test the possibility for an effective absorption of the unnecessary electromagnetic waves. The various metal powders are made into a thin sheet form by compositing through processing. The electromagnetic characteristics(complex permittivity, complex permeability) of the fabricated sheet are measured. As a result, we achieve –6.5 dB at 940 MHz(77.6 % absorption rate) with a 1.0 mm-thickness electromagnet wave absorber, and –9.5 dB at 940 MHz(88.8 % absorption rate) with a 2.0 mm-thickness absorber.

Atomic layer deposition (ALD) is widely used as a tool for the formation of near-atomically flat and uniform thin films in the semiconductor and display industries because of its excellent uniformity. Nowadays, ALD is being extensively used in diverse fields, such as energy and biology. By controlling the reactivity of the surface, either homogeneous or inhomogeneous coating on the shell of nanostructured powder can be accomplished by the ALD process. However, the ALD process on the powder largely depends on the displacement of powder in the reactor. Therefore, the technology for the fluidization of the powder is very important to redistribute its position during the ALD process. Herein, an overview of the three types of ALD reactors to agitate or fluidize the powder to improve the conformality of coating is presented. The principle of fluidization its advantages, examples, and limitations are addressed.

To develop Taraxacum platycarpum extract (TP)-loaded particles for tablet dosage form, various TP-loaded particles composed of TP, dextrin, microcrystalline cellulose (MCC), silicon dioxide, ethanol, and water are prepared using a spray-drying method and fluid-bed-drying method. Their physical properties are evaluated using angle of repose, Hausner ratio, Carr’s index, hardness, disintegrant time, and scanning electron microscopy. Optimal TP-loaded particles improve flowability and compressibility. Furthermore, 2% silicon dioxide gives increased flowability and compressibility. The formula of TP-loaded fluid-bed-drying particles at a TP/MCC/silicon-dioxide amount of 5/5/0.2 improves the angle of repose, Hausner ratio, Carr’s index, hardness, and disintegrant time as compared with the TP-loaded spray-drying particles. The TP-loaded fluid-bed-drying particles considerably improve flowability and compressibility (35.10° vs. 40.3°, 0.97 vs. 1.17, and 18.97% vs. 28.97% for the angle of repose, Hausner ratio, and Carr’s index, respectively), hardness (11.34 vs. 4.7 KP), and disintegrant time (7.4 vs. 10.4 min) as compared with the TP-loaded spray-drying particles. Thus, the results suggest that these fluid-bed-drying particles with MCC and silicon dioxide can be used as powerful particles to improve the flowability and compressibility of the TP.

In this study, the microstructure and characterization of an overlay welding layer using Fe-based composite powders are reported. The effects of the number of passes and composition of powders on the microstructure and mechanical properties are investigated in detail. The welding wire and powders are deposited twice on a stainless-steel rod using a laser overlay welding process. The microstructure and structural characterization are performed by scanning electron microscopy and X-ray diffraction. The mechanical properties of the first and second overlay layers are analyzed through the micro-Vickers-hardness tester and abrasion wear tester. In the second overlay layer, the hardness and specific wear are approximately 840 Hv and 2.0 × 10−5 mm3/Nm, respectively. It is suggested that the increase of the volume fractions of (Cr,Fe)7C3 and NbC phases in the second welding layer enhances the hardness and wear resistance.

본 연구는 돈사 내 저장된 돼지분뇨 슬러리에 액상 일라이트와 일라이트 분말을 첨가하여 악취에 미치는 영향을 분석하였다. 공시 돼지는 3원교잡종(Yorkshire×Land race×Duroc) 4개월령 암컷 비육돈 (65~68 kg) 360두를 이용하였다. 시험구 배치는 무처리한 대조구와 돼지분뇨 슬러리에 일라이트 액상 33%와 분말 5%를 첨가한 처리구로 3반복(40두) 120두에 적용하여 완전 임의배치법의 3주간 사양 시험 하였다. 악취 저감제 처리는 슬러리 피트(slurry pit ; 3.75 m×9 m×1.2 m, 20 ton 저장 규모)아래에 저장된 슬러리양을 계산하여 일정한 비율에 맞추고, 매주 액상 일라이트는 분무하거나 또는 일라이트 분말은 뿌려주었다. 악취 측정은 슬러리 피트 위 10 cm 위치에서 암모니아, 황화수소, 메틸 메르캅탄 및 디메틸 설파이드를 측정하였다. 사양기간 동안 암모니아 발생량은 일라이트 처리 형태에 의해 크게 영향을 주었다(p<0.05). 특히 암모니아 발생량은 액상 일라이트 33% 처리구는 30~46%, 일라이트 분말 5% 처리구에서는 30~54% 감소되었다. 황화수소 발생량은 2018년 12월 24일에 측정된 결과를 제외 하고 사양기간 동안 일라이트 처리 형태에 따라 유의적으로 영향을 주었다(p<0.05). 처리구의 황화수 소 발생 감소량은 대조구와 비교할 때, 액상 일라이트 33% 처리구에서는 16~60%, 일라이트 분말 5% 처리구는 7~59%였다. 측정기간 동안 평균 메틸 메르캅탄과 디메틸 설파이드 농도는 모든 시험구에서 발생되지 않았다. 3주간 사양 시험에서 평균 암모니아 농도의 경우, 액상 일라이트 33% 처리구는 38.6%, 일라이트 분말 5% 처리구는 39.7% 감소되었다(p<0.05). 평균 황화수소 농도는 액상 일라이트 33% 처리구와 일라이트 분말 5% 처리구는 비슷한 수준인 42.5% 감소되는 것으로 나타났다(p<0.05). 결론적으로 본 사양시험의 결과 액상 또는 분말 일라이트 처리는 돈사 내 발생되는 암모니아와 황화수소에 대한 유의미한 저감효과를 나타내었다.

In this study, effects of gelatin extracted from chicken feet powder and wheat fiber on physicochemical properties of gel were determined. Gel samples were prepared with different concentrations of chicken feet gelatin powder (2, 3, and 4%) and wheat fiber (0, 1, and 2%). Gel strength increased (p<0.05) with increasing concentrations of both chicken feet gelatin powder and wheat fiber. In each gel sample, melting point and apparent viscosity of the gel was affected by different chicken feet gelatin powder concentrations irrespective of the wheat fiber concentrations (0, 1, or 2%). The 4% chicken feet gelatin powder induced the highest melting point among all gel samples regardless of the wheat fiber concentration. The gel sample with 4% chicken feet gelatin powder and 2% wheat fiber showed the highest values (p<0.05). With the increasing concentrations of wheat fiber, CIE L* increased in gel samples with chicken feet gelatin powder at 3 and 4% (p<0.05). Lower CIE a* was observed in gel samples with wheat fiber at 1 and 2% compared to gel samples without wheat fiber (p<0.05). CIE b* of gel samples with 2% chicken feet gelatin powder was decreased as increasing the addition level of wheat fiber (p<0.05). Consequently, our studies show that chicken feet gelatin powder and wheat fiber mixture could be used as a food ingredient since they have various effects on physicochemical properties of gel such as an effect on gel strength, melting point, viscosity, and color.

처분 부적합 폐기물이란 원전운영이나 해체 시 처리, 고화 및 포장이 요구되는 방사성폐기물 등을 일컬으며, 대표적으로 분산 특성을 갖는 입자성 방사성폐기물을 예로 들 수가 있다. 이들 폐기물에는 원전 운영과정에서 발생되는 농축폐액의 건조 분말, 슬러리 및 슬러지, 향후 원전 해체과정에서 발생되는 온갖 분말 상태의 폐기물(콘크리트 파쇄물, 제염 슬러지 등), 그리고 제염이 용이치 못한 미세 크기의 방사능오염 토양 등이 있다. 입자성 폐기물을 기존의 고화방식으로 처리할 경우에는 최종 폐기물의 부피가 증가하는 단점을 갖게 되어 처분 비용의 증가 및 처분장의 수용성을 감소하는 결과를 야기할 수가 있 다. 따라서 이들 문제를 해결하고자 본 연구에서는 최종 폐기물 부피의 감용화를 위해 롤 압축 기술을 이용하여 분말의 펠렛화 연구를 수행하였다.

Fabrication of soft magnetic composite powders for the Fe2O3-Ca system by mechanical alloying(MA) has been investigated at room temperature. It is found that soft magnetic composite powders in which CaO is dispersed in α-Fe matrix are obtained by MA of Fe2O3 with Ca for 5 hours. Changes in magnetization and coercivity also reflect the details of the solidstate reduction process of hematite by pure metal of Ca during MA. The saturation magnetization of MA powders increases with increasing MA time and reaches a maximum value of 65 emu/g after 7 hours of MA. The average grain size of α-Fe in MA powders, estimated by diffraction line-width, gradually decreases with increasing MA time and reaches 52 nm after 5 hours of MA. It can also be seen that the coercivity of the 5-hour MA sample is fairly high at 190 Oe, suggesting that the grain refinement of already-produced α-Fe tends to clearly occur during MA.

The purpose of this study was to evaluate the antioxidant activity of roasted and germinated peanut flours. This study also aims to utilize it as a functional material to be applied to processed foods. The moisture, crude protein, crude fat and ash carbohydrate contents of the common peanut powder used in this study were 1.27, 25.63, 42.19, 2.38, 28.20 g / 100 g, respectively. The moisture content, crude protein, crude fat and ash carbohydrate in germinated peanut powder were 1.47, 25.86, 42.86, 2.25 and 26.66 g / 100 g, respectively. 26.52, 45.02, 2.33, 24.70, g / 100 g, and the dietary fiber content of peanut, roasted peanut and germinated peanut powder was 12.27, 13.05 and 14.22 g / 100g, respectively. The antioxidants and radical scavenging ability of polyphenols and flavonoids in peanut powder treated with germination and germination compared to ordinary peanuts. Resverasterol content was high in the germinated peanut powder. Especially, germinated peanut powder can act as a natural antioxidant.