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- Fabrication of artificial tissues/organs using extrusion-based cell printing technique
- A research team led by Prof. Geun Hyung KIM of the Department of Bio-Mechatronic Engineering proposed the world’s first hybrid cell-printing technique that combines a conventional extrusion-based cell-printing process with an electrohydrodynamic jet. The electric field stabilized the extruded struts of cell-embedding-hydrogel and reduced the damage to dispensed cells caused by the high wall shear stress in the dispensing nozzle. The new cell-printing process was optimized in terms of various processing parameters, applied electric field strength, nozzle movement speed, and distance between the nozzle tip and working stage. Because of these unique features, scholars in the field and cell-printing companies show their interest to learn more about this technique. To overcome shortcomings of 3D cell-printing process such as unstable flow and potential loss of cell viability, the research team suggested an innovative cell-printing process that combines a conventional extrusion-based cellprinting process with an electric field. The electric field in the cell-printing process stabilized the extruded struts of bioink and dramatically reduced the damage to dispensed cells caused by the high wall shear stress in the dispensing nozzle. For more detail about this research, please see attached article.
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- 작성일 2016-10-14
- 조회수 4269
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- Ultralow Power Complementary Inverter Circuits using p- and n- channel
- This work is an outcome of the long-term collaboration with Professor Dongmok Hwang at the School of Advanced Materials Science and Engineering of Sungkyunkwan University. Complementary inverter devices employing both p-and n-type field-effect-transistors (CMOS) are one of the most common building blocks in logic circuit designs. Recently, semiconductor nanowires used as conducting channels in field-effect-transistors (FETs), have attracted a great deal of attention due to their potential to overcome many critical limitations encountered when scaling-down traditional lithography-based thin-film transistor (TFT) devices. In this work, we first demonstrated a simple method to synthesize highly ordered axially doped p-type and n-type conducting channel regions on a single Si nanowire, where the transport properties of each p-type and n-type conducting channel region can be modulated by efficiently controlling the doping concentration. We also attempted to fabricate the p-n junction diode and CMOS inverter, each of which can be selectively fabricated on a single Si nanowire. Based on high-performance p- and n-type Si NW channel FETs showing especially the low threshold voltages, the fabricated NW CMOS inverters exhibited a low operating voltage (<3 V) while maintaining high voltage gain (~6) and ultra-low static power dissipation (≤0.3 pW) at ±3 V input voltages, thus making them suitable for high-density flexible logic device applications. While our work deals with one of most advanced issues concerning the device density of nanowire based logic devices, our approach will also have a significant impact on future work to exploit semiconducting one-dimensional or two-dimensional nanostructures including nanowires, nanotubes, nanocables or nanoribbon based CMOS for the next-generation logic circuits in flexible electronic applications.
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- 작성일 2016-10-14
- 조회수 4165
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- SKKU's New Challenges are Leading to Innovation in Universities
- Last year, SKKU announced the ‘New Challenge Project’ based on 5 sectors; (1) Convergence Education (2) Research (3) Global Alliance (4) Industrial Collaboration and (5) Innovation on administration, to become a world leading university. This project is a concrete blueprint that contains action plans of VISION 2020, which aims to be ranked within the top 10 in Asia and top 50 in the world by 2020. (1) Research-focused University Leading Future Industry Performance is visible with various indexes in research and industrial collaboration - Published 4,865 SCI research articles, doubled from 2,782 in 2010 - Research fund is $300 mil, increased by 50% from 2010 - The number of international research papers per faculty is 0.98 (No.1 on Korea) - Income from Technology Transfer is increased from $2mil (2010) to 3 mil won (2015) (2) Software Courses to Foster Creative Talents SKKU is focusing on cultivating talented individuals who have both convergence thinking ability and professional knowledge. In particular, SKKU is striving to foster software experts by offering software courses to students in human and social sciences. Also, the College of Software was established recently by merging with Software and Computer Engineering to give a wider scope of education in this field. (3) Professional and Practical Graduate School 31 teams, the largest number among private universities in Korea, were selected for BK21+ because of SKKU’s greatness in the scholarship and research environment. SKKU has 2 IBS (Institute for Basic Science) and receives support through research funds totaling about $10 mil annually over 10 years. Also, the Grand ICT Research Center has just opened in Pangyo Techno Valley and is expected to become the center of technology development /transfer/patent processes for venture businesses.
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- 작성일 2016-10-14
- 조회수 4099
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- SKKU Students win award at WCCM 2016
- Soojin Jo, a student in the Mechanical Engineering Doctoral Program was awarded the ‘IACM Fellowships for Early Career Female Researchers’ by IACM (International Association of Computational Mechanics) at WCCM (World Congress on Computational Mechanics). She was previously selected as a scholarship student of GPF (Global Postdoc Fellowship) in 2012 and has been working on the research ‘DNA Super Coil Mechanism based on elastic network modeling’ for the past five years. At WCCM 2016, she published a dissertation on ‘Homologous Recombination in DNA Foldback Intercoil Structure’ and won award. Jang Kyun Lim, a student in the SAINT Doctoral Program also received a ‘Travel Award’ by dissertation for this work ‘Suggesting Optimum Design for Thermal Cutout Lamination’, which has been supported by BRL (Basic Research Laboratory) for the past five years. The ‘Travel Award’ is for those outstanding students who are in the top 10% among 700 students who participated in WCCM congress. Some privileges such as exemption of WCCM registration fee will be given. WCCM is the one of the world’s largest and powerful conferences for computational mechanics which IACM holds biannually. Theorists and commentators in various engineering fields participate. WCCM 2016 was held at Coex, Seoul from July 24th to July 29th. This event was successfully secured by Young Jin Kim (deceased), Ex-vice president of Natural Science Campus of SKKU, and over 2,000 people from related areas attended.
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- 작성일 2016-08-18
- 조회수 4285
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- Next generation perovskite solar cell with improved the efficiency and stability
- Solar energy is an expected source of energy that can play an important role in energy supply in the future of the world. As part of the response to changes in the environment due to global climate change, there is an ongoing effort to increase the proportion of power generation from renewable energy. It is expected that solar cells will take the largest proportion in such a flow. Recently, researchers have focused on organic-inorganic composite material having a perovskite structure that would allow low-cost and high-efficiency solar cell as a new photo-active material. Perovskite solar cells, one of the ten scientific breakthroughs in 2013, are in close proximity to the efficiency of crystalline silicon (~ 25 %) solar cells by the rapid improvement of the efficiency (from 2.2 % in 2008 to 22% in 2016). It, as next-generation solar cell with superior performance in low-cost materials that are based on cheap solution process, are expected to be able to replace the conventional silicon solar cells. Perovskites are materials described by the formula ABX3, where X is an anion and A and B are cations of different sizes (A being larger than B). Perovskite which is used for solar cells has methylammonium in the A site, B site is lead or tin ion, and X site is composed of halide ions. It simply shows the following attractive properties as a photo-active materials; a bandgap of around 1.6 eV, high extinction coefficient, with long electron-hole diffusion length (0.1 ~ 1m). The most successful architecture of the perovskite solar cells has adopted the titanium oxide and the Spiro-OMeTAD(2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamine)-9,9′-spirobifluorene) as charge transfer layer. Despite the high efficiency, However, the current - voltage hysteresis (asymmetry result in current-voltage measurement between forward and revers scan) has dropped reliability of the device. Meanwhile, perovskite solar cells using PEDOT: PSS (poly (3,4-ethylenedioxythiophene) poly (styrene sulfonate)) and PCBM (phenyl C61 butyric acid methyl ester) also can be manufactured. Current-voltage hysteresis that reduces the reliability of the solar cells was significantly suppressed when producing a solar cell in this structure. Another problem of the perovskite solar cells is low stability. This material is highly vulnerable to moisture and heat. The efficiency of the solar cell can be rapidly decreased within a few hours to exposure in the air. Therefore, it is an important issue for practical use to improve the stability of the perovskite solar cells. The researchers reported highly efficient perovskite solar cell based on chemically stable Nickel Oxide (NiO) with 16.40 % of power conversion efficiency by replacing PEDOT:PSS, organic charge transporting material. Although PEDOT:PSS has superior functionality to extract charges selectively from the perovskite layer, PEDOT:PSS promotes the decomposition of the perovskite which is moisture-sensitive due to its hygroscopic nature. On the other hand, nickel oxide, can improve the stability of the perovskite solar cells by retaining the chemical stability. Perovskite solar cells based on NiO, however, have suffered from relatively lower performance with smaller fill factor and photocurrent density compared to devices based on PEDOT:PSS. The researchers prepared the ultrathin NiO films (a few nanometers in thickness) deposited by atomic layer deposition (ALD) method for highly efficient perovskite solar cells. The Ultrathin Nickel Oxide showed an improved hole transport property compared to the bulk Nickel Oxide films. In addition to this, High transparency of such a thin nickel oxide helps the perovskite to exhibit the high power conversion efficiency. Further, the solar cell has maintained 90% of the initial efficiency over 500 hours when stored under inert gas atmosphere. The result is expected to be the basis for the development of highly efficient and reliable perovskite solar cell for future commercialization. The research was published in ‘Nanoscale’.
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- 작성일 2016-08-18
- 조회수 4242
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- Six Thailand Students at Doctoral Degree Level will Study at SKKU as a Part of NANOTEC-SKKU Program
- Six students belonging to NANOTEC (Thailand’s Nanotechnology Center) will study at SKKU’s SAINT (Sungkyun Advanced Institute of Nano Technology) from the 2nd semester of 2016, in order to exchange scientific knowledge and to learn SKKU’s advanced engineering education/research. Among these students, is one postdoc researcher, while the other students are under the doctoral program. Thailand’s government is showing great interest towards SKKU’S program; Her Royal Highness Crown Princess Maha Chakri Sirindhorn invited the students to her official residence and held a sending event for them. She mentioned that “This program is a very good opportunity where talented students of Thailand can learn advanced education and research in engineering at SKKU. Devote yourselves to study.” NANOTEC-SKKU collaboration started in 2015 with 9 students and applying students in the future is expected to increase due to the high satisfaction rate of the program. List of Students as follows: Postdoc: Dr. Lunjakorn Amornkitbamrung Doctoral: Arthitiya Prasertnavakul, Dulyawat Doonyapisut, Weerawat To-a-ran, Sillawan Aschakulporn, Porawin Charoennan
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- 작성일 2016-08-18
- 조회수 4342
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- World's first technology to analyze and visualize in 3D of a solar battery
- A research team of the College of Information and Communication Engineering at SKKU discovered an energy defect in CulnGaSeS structure of a solar battery and three-dimensionally (3D) visualized the defect in shape and distribution. The main title of the research is “Defect Visualization of Cu(InGa)(SeS)2 Thin films using DLTS Measurements” and it was published in the Science Report in the August edition. The research was led by Sung Hur PhD., and Prof. Byoung D. Choi from the College of Information and Communication Engineering in SKKU, and Dong Ho Lee, PhD., from Samsung SDS, while Prof. Hun Young Choi from Dongguk University and Prof. Hee Jae Kang from Chungbuk National University also participated. There have been many studies on the impact of the defect on solar batteries and its efficiency, but it was not easy to investigate due to the lack of measurement methods. This research provides a fascinating route to discover distinct types of defects (acceptor or donor) that can affect the efficiency of solar batteries, by analyzing microdefects quantitatively with DLTS methods and visualize with various depths in the stage of absorption. SKKU explains that “this technology will contribute to an increase in reliability and to improve the life cycle of cells related to semiconductor memory, solar batteries, and display.”
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- 작성일 2016-08-18
- 조회수 4364
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- Generating Metamaterial, inspired by the motion control of an Aphid’s leg
- Generating Metamaterial, inspired by the motion control of an Aphid’s leg Metamaterials have made the exotic control of the flow of electromagnetic waves possible, which is difficult to achieve with natural materials. In recent years, the emergence of functional metadevices has shown immense potential for the practical realization of highly efficient photonic devices. However, complex and heterogeneous architectures that enable diverse functionalities of metamaterials and metadevices, have been challenging to realize because of the limited manufacturing capabilities of conventional fabrication methods. In this research, it was discovered that three-dimensional (3D) modular transfer printing can be used to construct diverse metamaterials in complex 3D architectures on universal substrates, which is attractive for achieving on-demand photonic properties. This study is inspired by Dry-adhesion Control of the leg of an Aphid, which climbs walls without sticky materials and moves upside down on plant stems. By Dry-adhesion Control, Aphids can regulate the attractive force between leg and object without any restriction. As described in picture 1, the surface area of the leg that is touching the object can be maximized or minimized, depending on the blood pressure of the back of the leg. In this research, a rubber stamp is designed and made to work in a similar manner with that of this insects’ leg motion. As seen picture 2, the rubber stamp with a sharp end can print anything easily due to a minimized surface area (adhesion-off) between metamaterials and the rubber stamp. Metamaterial can be removed from the maximized surface area (adhesion-on) if the sharp end crumbles. This method provides a fascinating route to generate flexible and stretchable 2D/3D metamaterials and metadevices with heterogeneous material components, complex device architectures, and diverse functionalities. About Research Laboratory of Biomimetic & Photonic Properties The Research Laboratory of Biomimetic & Photonic Properties was established in 2014 as a part of SKKU Advanced Institute of Nanotechnology (SAINT). Prof. SeungWoo Lee and 7 students of undergraduate and graduate levels are researching biomimetic by using ductile nanomaterial such as DNA origami/ polymers to create various light-material interactions and more. The laboratory is pursuing the convergence of various academic knowledges, including chemical engineering, physics, electrical engineering, and chemistry. We participate in the competition of biomimetic design at Harvard University, and several joint researches are in development with MIT, Harvard University, and Caltech.
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- 작성일 2016-08-18
- 조회수 4370
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- Prof. Daniel Jong Schwekendiek in BBC interview: Why South Koreans are getting taller?
- The average height of South Korean women has grown by 20cm in the past hundred years, which is the most rapid increase in the world. BBC Newshour asked for an opinion about this research from prof. Schwekendiek (Academy of East Asian Studies), who has published several dissertations about the trend of height in Korea. Prof. Schwekendiek explained that the main reason for the result of the research is improvement of nutrition in Korea; Koreans are having traditional meals containing lots of vegetables, but also eating more milk and meat than in the past. He mentioned that the average height of Koreans is the tallest among Asian countries including Taiwan, Japan, China, and North Korea. Prof. Daniel Jong Schwekendiek was born in Korea but raised in Germany. He received a bachelor, masters, and doctoral degree at University of Tubingen. He has worked as a researcher at Seoul National University, University of Oxford, and University of California, Berkeley, and has been a professor at SKKU since 2011. http://www.bbc.co.uk/programmes/p042ndys
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- 작성일 2016-08-01
- 조회수 4354
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- Prof. Kang Yoon Lee received the award of ‘2016 Top 100 R&D Performance in Korea’
- Prof. Kang Yoon Lee, School of Electronic and Electrical Engineering at SKKU, received the award of ‘2016 Top 100 R&D Performance in Korea’, with the study of a high-speed wireless charging and transceiving microchip that can be applied to triple international standard modes (A4WP, WPC, PMA). On July 7th (Thurs), The Ministry of Science, ICT, and Future Planning selected the Top 100 researches that have shown great results and awarded them. Also for those projects that were recognized as excellent, the government prepared an exhibit room and introduced researches briefly to the public. Since 2006, the Korean government has chosen a hundred outstanding research projects to raise the self-esteem of scientists and to promote the successful researches of the country. This year, 54,000 researches were completed under the government’s funds and 620 were on the list of recommendation. Among the nominees, experts of research and business industries selected a hundred researches based on the impact to the country and possibility of positively affecting economics. Prof. Lee said “from this award, we proved SKKU’s great research abilities and I will continue focusing on research and education.”
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- 작성일 2016-08-01
- 조회수 4547