Here, we report the development of a new and low-cost core-shell structure for lithium-ion battery anodes using silicon waste sludge and the Ti-ion complex. X-ray diffraction (XRD) confirmed the raw waste silicon sludge powder to be pure silicon without other metal impurities and the particle size distribution is measured to be from 200 nm to 3 μm by dynamic light scattering (DLS). As a result of pulverization by a planetary mill, the size of the single crystal according to the Scherrer formula is calculated to be 12.1 nm, but the average particle size of the agglomerate is measured to be 123.6 nm. A Si/TiO2 core-shell structure is formed using simple Ti complex ions, and the ratio of TiO2 peaks increased with an increase in the amount of Ti ions. Transmission electron microscopy (TEM) observations revealed that TiO2 coating on Si nanoparticles results in a Si-TiO2 core-shell structure. This result is expected to improve the stability and cycle of lithium-ion batteries as anodes.

Conventional rotary sawing machine for cutting lumber generates severe amount of dust scattering to the environment. In this research, the design improvement of the rotary sawing machine is achieved to significantly reduce the dust scattering by the design process utilizing computational fluid dynamics (CFD) analysis. Several design candidates for the design improvement of the rotary saw system were proposed and modeled, and CFD analyses were performed to choose the best design in viewpoint of the least dust scattering. CFD analysis proved to be very useful to predict the characteristics of the air flow inside the saw system. The movement of dust particles with the air flow during the sawing process was analyzed for various design features of the saw system. The most efficient design to minimize the amount of dust particles ejected from the saw system was chosen based on the CFD analysis results. Then, the prototype of the best candidate of the improved rotary saw machine was built and the amount of dust particles were measured to verify its performance.

본 연구는 난지형 마늘의 주아재배를 통한 우량종구 생산을 위하여 주아크기, 파종시기, 재식거리 시험을 실시하였다. 남도마늘 주아는 클수록 출현이 빠르며 엽수, 엽폭, 초장의 신장이 좋은 편이며 단구크기도 커졌으나 단구형성율은 떨어졌다. 특히 단구형성율은 남도마늘 주아 0.1g처리구에서 높았으며 주아 크기가 클수록 낮아졌다. 대서마늘 주아는 남도마늘 주아에 비해 발아와 생육이 빠른 편이나 단구형성율이 낮고 단구크기가 작았다. 대주아 파종간격에 따른 생육은 파종간격이 넓을수록 엽수가 많고 엽폭도 넓었으며 구크기와 인편크기도 커졌으나 처리에 관계없이 단구형성율은 현저히 떨어졌으며 분구된 인편중 10×15cm처리구에서 3g이상 인편이 많고 경제성도 있어서 대주아를 이용한 인편 생산가능성이 있었다. 남도마늘 주아의 경우 9월 11일 파종구에서 수확주율, 단구형성율, 수량이 가장 많았다. 대서마늘의 경우 주아파종시기가 늦어질수록 수확주율이 많았지만 단구크기는 작아졌으며 단구형성율은 처리에 관계없이 낮아서 제주지역에서 재배는 적합하지 않았다.

The inter-particle distance between diamonds on the segment surface of sawing blade predicted theoretically and measured experimentally followed a Gamma or Weibull function, rather than a normal distribution function. These results suggest that random dispersion of diamond particles in the segment may not be an efficient way of improving cutting efficiency of the blade.