• Journal of the Korean Ceramic Society
• /
• v.31 no.10
• /
• pp.1169-1175
• /
• 1994

Five Al2O3/SiC/metal composites with four different particle sizes of green SiC abrasive grains are grown by the directed oxidation of an commercially available Al-alloy. Oxidation was conducted in air at 100$0^{\circ}C$, 96 hours long. Slip casted SiC-fillers were placed on the alloy or SiC powder deposited up to the required layer thickness. Their microstructures are described and measurements of density, elastic constants, frexural strength, fracture toughness and work of fracture are reported. The results are compared with those of commercial dense sintered Al2O3. The properties of produced materials have a strong relationship to not only the properties of Al2O3, SiC, Al and Si but also to the phase share and phase distribution. The composite materials are dense (0.5% porosity), tough (KIC = 3.4~6.4 MPa{{{{ SQRT { m} }}), strong ({{{{ sigma }}B = 170~345 MPa) and reasonably shrinkage free producible. The reinforcements is attained mainly through the plastic deformation of ductile metal phase.

• Journal of the Korean Academy of Esthetic Dentistry
• /
• v.27 no.2
• /
• pp.66-74
• /
• 2018

Composite resin restoration on class II cavities is a challenging procedure since it is tough to replicate proper contact, the natural shape of the tooth, etc. Moreover, it is not familiar with the procedure and tools for this specific situation, neither. Nowadays the patients, however, request more and more composite restorations which are relatively quick and more esthetic. In this case report, the class II composite resin restoration procedure is illustrated step by step. Every step must be considered its final consequence thoroughly. In this approach, we can minimize the finishing procedure and save our effort and time.

• International Commerce and Information Review
• /
• v.3 no.2
• /
• pp.17-27
• /
• 2001

The paper at first gives an introduction to e-commerce, recalls the birth and the growth of an e-commerce giant Chinapages.com in the tough environment in the primary stage of the development of e-commerce in China, provides an overview of its e-business scope and its experience in its e-business development, then describes its present favorable and unfavorable e-business e-environment and its challenges in its future development. Finally it concludes that Chinapages' future is bright and promising with China's WTO entry just around the corner, if Chinapages takes advantages of the opportunities and faces the challenges with confidence and aggressiveness in the new era of e-commerce.

• Research in Mathematical Education
• /
• v.15 no.2
• /
• pp.197-208
• /
• 2011

By using the recording and quantitative analysis of two videos about "The multiplication and division of the Fractions" and the "Flanders Interaction Analysis System," we classified the teachers' language of instruction in algebra classroom and also analysis the language of instruction in the different teaching process. The results after the analysis as follows: (1) The proportion of time was taken in teachers' language of instruction is high and vary in types, most of the teachers' language is teachers' question; (2) In the different teaching process, the proportion of time was taken in teachers' language of instruction is different; (3) Teachers attached importance to explain the example and had the similar teaching strategy, but the teachers' language is different; (4) In the practice process, teachers placed importance on exploring the tough question and its teaching strategies are different. The teachers' questions are the main teachers' language of instruction.

• Tunnel and Underground Space
• /
• v.25 no.2
• /
• pp.168-185
• /
• 2015

The thermal-hydrological-mechanical (T-H-M) behavior of rock mass surrounding a large-scale high-temperature cavern thermal energy storage (CTES) at a shallow depth has been investigated, and the effects of hydrological conditions such as water table and rock permeability on the behavior have been examined. The liquid saturation of ground water around a storage cavern may have a small impact on the overall heat transfer and mechanical behavior of surrounding rock mass for a relatively low rock permeability of $10^{-17}m^2$. In terms of the distributions of temperature, stress and displacement of the surrounding rock mass, the results expected from the simulation with the cavern below the water table were almost identical to that obtained from the simulation with the cavern in the unsaturated zone. The heat transfer in the rock mass with reasonable permeability ${\leq}10^{-15}m^2$ was dominated by the conduction. In the simulation with rock permeability of $10^{-12}m^2$, however, the convective heat transfer by ground-water was dominant, accompanying the upward heat flow to near-ground surface. The temperature and pressure around a storage cavern showed different distributions according to the rock permeability, as a result of the complex coupled processes such as the heat transfer by multi-phase flow and the evaporation of ground-water.

• Food Science and Preservation
• /
• v.8 no.2
• /
• pp.140-145
• /
• 2001

Although the drying times of paddies were significantly shortened by the application of higher drying temperatures, the 12, 10 and 8 hours were needed for the reduction of moisture contents from 23.55 to 15% at the temperatures of 45, 50 and 55$\^{C}$, respectively. Milling yields(MY) and rice rates(HRR) were decreased by increasing of the drying temperature. The MY ratios were 75.50, 75.42 and 75.31% and HRR were 93.28, 92.14 and 91.12% in drying temperature of 40, 50 and 55$\^{C}$, respectively. In the milling processes of tough rice with the used of a milling machine equipped with both of abrasive and friction types in a body, the reduction rates of bran and the occurrence of broken rice increased with the pressures at outlet or the recycled passing tines. In the process for humidified friction whitening of rice, it was found that the optimum addition rate of water for the best quality was the 11.2 liters per tone of white rice.

• International Commerce and Information Review
• /
• v.4 no.2
• /
• pp.223-231
• /
• 2002

Alibaba.com has developed very fast and created a miracle in the international e-business community since it was established just three years ago. The paper at first introduces its rapid development from its establishment, the construction of its websites and its e-products and e-services, its mode of operation and corporate culture. Secondly it analyses the reasons why it has not only survived, but also developed very fast and begun to make profits despite the cut-throat competition in the e-business community in the tough e-environment in China. Then it displays and analyzes its competitive edges and the challenges it is confronted with. Finally it predicts its promising future.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.19 no.2
• /
• pp.16-21
• /
• 2011

Immobilization of biosorbent is very important for application to real wastewater treatment process because biosorbent itself does not have enough tough structure. Therefore, resent research on heavy metal biosorption using biomass has been focused on its efficient immobilization method. To improve the mechanical strength of freely biosorbent, many immobilization methods have been suggested for applications to the biosorbent such as microorganisms or polysaccharides. In this study, various immobilization methods such as adsorption, covalent binding, entrapment, encapsulation, and crosslinking will be introduced.

• Elastomers and Composites
• /
• v.56 no.2
• /
• pp.85-91
• /
• 2021

In this study, different types and shapes of various particles produced on the asphalt pavement road were analyzed. Road dust at a bus stop was collected and was separated as per their sizes by using a sieve shaker. Tire-road wear particles (TRWPs), asphalt pavement wear particles (APWPs), mineral particles, plant-related particles, glass beads, glass particles, road paint wear particles, plastic particles, and fibers were observed herein. The types and shapes of the particles varied depending on their sizes. TRWPs larger than 500 ㎛ were not observed. TRWPs with a size of 212-500 ㎛ were rarely present, but many TRWPs with a size smaller than 212 ㎛ were observed. APWPs were observed for whole-particle sizes of below 1,000 ㎛. A variety of particles on the road would lead to lower friction between the tires and the road, thereby increasing the braking distance of vehicles. Most of the particles include mineral particles, glass particles, and APWPs with rough surfaces. Therefore, the abrasion of the tire tread would accelerate owing to friction with the tough particles.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.28 no.2
• /
• pp.127-136
• /
• 2022

Purpose: The purpose of this study was to describe the career choice experiences of nursing students. Methods: A phenomenological approach was used for the study. Data were collected from September 1 to October 1, 2021, using open-ended questions in-depth interviews. Ten nursing students who had decided to find a job or complete an application to an employment institution participated in this study. Results: The four categories obtained as results were "Preparing myself," "Chosen after conflict," "Going through a tough tunnel and settling down," and "Waiting with anticipation and worry." Conclusion: This study explored the meaning and essence of the career choice experiences of nursing students. These results will provide basic data that can help nursing students make career choices.