This study analyzes the mechanical properties, including the attrition rate, of 50 μm size yttria-stabilized zirconia (YSZ) beads with different microstructures and high-energy milling conditions. The yttria distribution in the grain and grainboundary of the fully sintered beads relates closely to Vickers hardness and the attrition rate of the YSZ beads. Grain size, fractured surfaces, and yttrium distribution are analyzed by electronic microscopes. For standardization and a reliable comparison of the attrition rate of zirconia beads with different conditions, Zr content in milled ceramic powder is analyzed and calculated by X-ray Fluorescence Spectrometer(XRF) instead of directly measuring the weight change of milled YSZ beads. The beads with small grain sizes sintered at lower temperature exhibit a higher Vickers hardness and lower attrition rate. The attrition rate of 50 μm YSZ beads is measured and compared with the various materials properties of ceramic powders used for high-energy milling. The attrition rate of beads appears to be closely related to the Vickers hardness of ceramic materials used for milling, and demonstrates more than a 10 times higher attrition rate with Alumina(Hv ~1650) powder than BaTiO3 powder (Hv ~315).

Introduction The study chooses smartphone applications which have update experience as the study case to analysis if it will cause customer attrition. Application updates aims to make up the bugs which may cause bad effects on using, while in fact, most changes will be resisted by customers. We adapt three elements to collect data about the attitude of customers toward applications update, the conclusion illustrates, customers will resist changes in some conditions and cause customers attrition. Therefore, application developers should focus on the personal emotional reaction and cognitive evolution as well as predict what may influence the customers normal use after the applications update to make correct update decisions. In order to define the relationship between variable and result., we take smartphone application which had experienced update as examples and choose fsQCA as the methodology to analysis. Literature Review Resistance to change is a psychological process, Brehm（1966）claims customers resist to change origins from their believe that they have rights to control free, when this rights be challenged, this resistance behavior will happen due to they want to protect their own rights. Some scholars distinguished the concept of resistance to change: when receptors in the low involvement or limited cognize, their resistance behaviors is likely to be considered as the passive resistance; otherwise, the behaviors would be recognized as active resistance (Nabih,1997). Bagozz and Lee（1999) think that functional barrier is an important factors which influence the degree of innovation receptance, when customers think products after update cannot meet their function needs will cause resistance to change. Resistance always occur passively, bemuse of the disturb of the former habits of using (Ram &Sheth 1989), and former studies also indicate that prejudice towards changes is one of significant factors. Because changes are uncertainty, Fiske and Taylor（1991）claims that uncertainty can make people hate changes and Whitson and Galinsky（2008）consider aversion will be the strong driver of resistance to change to reduce uncertainty and risk. In terms of a company, the cost of maintaining a old customer is much lower than these of develop a new user, Actually, customer attrition is response of entrepreneur revenue and the vital section in development of companies. The famous american honesty management scholar Frederic Reichheld’s research indicates that when the extension of the commercial relationship of entrepreneur and customers, companies can acquire fatter profit through the relationship. Conclusions This study chooses fsQCA as methodology to define the relationship between resistance to change and customer attrition instead of using structural equation modeling. Sometimes, even customers have right cognitive evolution towards changes, when they find their efficiency be influenced by it, they also resist to change; while adverse emotional reaction also has an adverse effect on customer retention though they build positive cognitive evolution about changes. there is a remain circumstance of lossing of customers that when customers hate changes and they find their efficiency be influenced by update, the honesty of this product will also decrease. This three condition all contribute to customers attrition which should be paid more attention by companies.

Particle size reduction is an important step in many technological operations. The process itself is defined as the mechanical breakdown of solids into smaller particles to increase the surface area and induce defects in solids, which are needed for subsequent operations such as chemical reactions. To fabricate nano-sized particles, several tens to hundreds of micron size ceramic beads, formed through high energy milling process, are required. To minimize the contamination effects during highenergy milling, the mechanical properties of zirconia beads are very important. Generally, the mechanical properties of Y2O3 stabilized tetragonal zirconia beads are closely related to the mechanism of phase change from tetragonal to monoclinic phase via external mechanical forces. Therefore, Y2O3 distribution in the sintered zirconia beads must also be closely related with the mechanical properties of the beads. In this work, commercially available 100μm-size beads are analyzed from the point of view of microstructure, composition homogeneity (especially for Y2O3), mechanical properties, and attrition rate.

에티오피아는 1994년을 기점으로 교육개혁을 시도하면서 보편적 교육 및 질 높은 교육 의 실현을 위한 기틀을 마련하였다. 특히, 두 목표를 실현하기 위해 1994년 교육개혁은 질 높은 교사의 수급을 위한 교사 양성소의 교육과정 변화 및 임금 인상에 따른 승진제도 마련 등의 유인책을 제도에 포함시켰다. 이러한 유인책에도 불구하고 여전히 에티오피아 내 교사수급은 현저한 문제점으로 지적되고 있으며 특히 질 높은 교사의 이직은 심각한 사 회적 문제로 부각되고 있는 실정이다. 따라서 본 연구는 에티오피아 교사들은 왜 이직을 하려고 하는 지에 대해 분석하고자 한다. 본 연구에서는 에티오피아 교사 승진제도 및 낮 은 임금 구조가 교사의 이직에 영향을 미친다는 결론에 도달한다. 첫째, 불투명한 승진구 도는 교사의 이직과 관련성이 있다. 둘째, 승진에 따른 정치관련 업무 증가는 교사의 이직 에 영향을 미친다. 셋째, 교육 및 정치의 연관성으로 인한 교직 내 민주적인 문화형성이 어렵다. 넷째, 승진으로 인한 급여 인상이 매력적이지 않다.

In this research, magnesium powder was prepared by gas atomizing. Refinement behaviors of magnesium powder produced under different conditions were investigated using a mechanical milling (attrition milling) process. Analyses were performed to assess the characterization and comparison of milled powder with different steel ball sizes and milling times. The powders were analyzed by field emission scanning electron microscope, apparent density and powder fluidity. The particle morphology of the Mg powders changed from spherical particles of feed metals to irregular oval particles, then plate type particles, with an increasing milling time. Because of the HCP structure, deformation occurs due to the existence of the easily breakable C-axis perpendicular to the base, which results in producing plate-type powders. An increase in ball size and the impact energy of the magnesium powder maximizes the effect of refinement. Furthermore, it is possible to improve the apparent density and fluidity according to the smoothness of the surface of the initial powder.

본 연구에서는 저품위 견운모를 대상으로 파쇄, 해쇄 및 침강분리 공정을 적용하여 각각의 단 위공정의 특성과 품위향상에 미치는 영향에 대해 고찰하였다. 원광석의 주 구성광물은 견운모, 석영, 방해석이었으며, 체가름 결과, 입자의 크기가 작아질수록 견운모의 함량은 높아지는 반면, 불순광물의 함량은 상대적으로 감소하는 경향을 보였다. 조암광물의 형상 및 원소분석 결과, 메디아를 이용하는 분쇄 방식보다는 입자의 표면에 선택적으로 충격력과 전단력을 가해줄 수 있는 해쇄 방식이 적절한 것으로 판단되었다. 해쇄 시간 및 슬러리 농도가 증가함에 따라 미립자 발생량이 증가하였으며, 장시 간 해쇄한 경우 미립자 내 불순광물인 석영과 방해석의 혼입량이 증가하는 결과를 보였다. 해쇄 없이 단순하게 분산한 슬러리를 20분 동안 정치 후 회수한 정광의 생산율은 15.4 wt%, K2O 함량은 9.84 wt% 였다. 10분 해쇄한 후 40분 침강 분리하여 회수한 정광의 생산율은 23.4 wt%로 증가한 반면 K2O 함량은 9.71 wt%로 감소하였다. 회수된 최종산물은 대부분 판상의 입자로 관찰되었으며 입자표 면의 원소분석 결과, 주 구성 원소는 Si, Al, K로 견운모의 화학조성을 보였다.

본 연구에 세는 제빵용 소맥분의 손상전분 함량을 비교 분석하여 최적의 작업조건 설정과 제빵 품질을 향상시킬 목적으로 손상전분 함량을 각각 달리하여 반죽의 물리적 특성 및 제빵 적성을 검토하였다. DNS와 CWRS 및 SW 등의 소맥을 제분하여 손상전분 함량 6.5%, 8.2%, 9.0%, 9.5% 및 10.5%를 함유한 시료로 제조한 반죽의 물리적 및 이화학적 특성인 farinogram, extensogram, amylogram 등을 조사하였으며