• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.17 no.1
• /
• pp.63-77
• /
• 2022

The importance of start-ups and venture companies in the Korean economy is growing. However, the successful growth of startups and venture companies are still challenging as 70% of startups fail within 5 years. A new perspective on innovation is essential to overcome the liability of newness and the liability of smallness in the existing market and obtain the competitive advantage. Recent phenomenon in the Korean startups ecosystem is the remarkable growth of unicorns and future unicorns. Their business models, types of business, and success cases serve as a good example. Neverthless, the process of unicorn and future unicorn startups making new industries and innovative business has poorly understood. In this paper, we first define 175 unicorns and future unicorn startups participating in the K-unicorn project as a unicorn group and analyze current trends of the group. Then the in-depth analyses of industry sectors are conducted. Specifically, focusing on the unicorn forming the new market, we examine the unicorn making the processes of industry category innovation through the business innovation model. Lastly, broadening the scope of the analysis to the unicorn group, policy implications in startups and venture ecosystem are suggested.

• The Journal of Korean Academy of Prosthodontics
• /
• v.45 no.4
• /
• pp.407-418
• /
• 2007

Purpose: The objective of this study was to evaluate the effects of hydrofluoric acid concentration & etching time on the shear bond strength between IPS Empress 2 ceramic and resin cement. Material and methods: Thirty three rectangular shape ceramic specimens($20{\times}12{\times}5mm$ size, IPS Empress 2 core materials) were used for this study. The ceramic specimens divided into ten experimental groups with three specimens in each group and were etched with hydrofluoric acid(4%, 9%) according to different etching times(30s, 60s, 90s, 120s, 180s). Etched surfaces of ceramic specimens were bonded with resin cement(Rely X Unicorn) using acrylic glass tube. All cemented specimens were tested under shear loading until fracture on universal testing machine at a crosshead speed of 0.5mm/min and the maximum load at fracture(kg) was recorded. Collected shear bond strength data were analyzed with one way ANOVA and Duncan tests. All etched ceramic surfaces were examined morphologically using SEM(scanning electron microscopy). Results: Shear bond strength of etching group$(35.89{\sim}68.01MPa)$ had four to seven times greater than no-etching group$(9.53{\pm}2.29MPa)$. The ceramic specimen etched with 4% hydrofluoric acid for 60s showed the maximum shear bond strength$(68.01{\pm}11.78MPa)$. Ceramic surface etched with 4% hydrofluoric acid for 60s showed most retentive surface texture. Conclusion: It is considered that 60s etching with 4% hydrofluoric acid is optimal etching methods for IPS Empress 2 ceramic bonding.