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KAIST Seals the Deal for Kenya KAIST Project
KAIST will participate in Kenya’s strategic economic development plan under the provision of a turnkey-based science and technology education consultancy for the establishment of the Kenya Advanced Institute of Science and Technology (Kenya KAIST).KAIST signed the contract on November 30 with the Konza Technopolis Development Authority to establish Kenya KAIST. Korea Eximbank will offer a 95 million USD loan to the Kenyan government for this project. The project will include the educational and architectural design and construction of Kenya KAIST. The campus will be constructed in the Konza Techno City nearby Nairobi by 2021, with the first batch of 200 graduate students starting classes in 2022. KAIST, in consortium with Samwoo and Sunjin architecture and engineering companies, will take the lead of the three-year project, with the kick-off ceremony planned at the end of next January in Nairobi. The Kenyan government plans to transform Kenya into a middle-income country under Vision 2030 through promoting science, technology, and innovation for national economic growth. Nicknamed Africa’s Silicon Savannah, Konza Techno City is a strategic science and technology hub to realize this vision. To this end, the medium-term plan set a goal to provide specialized research and training in various leading-edge engineering and advanced science fields.In the two-phase evaluation of the consultancy bidding, KAIST won preferred bidder status in the technical proposal evaluation, outbidding three other Korean consortia. Invited to the financial proposal bidding, the KAIST consortium successfully completed month-long contract negotiations with Kenya last week.KAIST will develop academic curricula for six initial departments (Mechanical Engineering, Electrical/Electronic Engineering, ICT Engineering, Chemical Engineering, Civil Engineering, and Agricultural Biotechnology), which will lay the ground work for engineering research and education in Kenya to meet emerging socioeconomic demands. In addition, KAIST will provide the education of basic sciences of math, physics, chemistry, and biology for students.It is also notable that the Kenyan government asked to develop an industry-academy cooperation program in Konza Techno City. It reflects the growing industrial needs of Kenya KAIST, which will be located in the center of the Konza Technopolis. It is anticipated that the technopolis will create 16,675 jobs in the medium term and over 200,000 after completion, positioning Kenya as an ICT hub within the region.KAIST also shares a similar history of establishment with Kenya KAIST, as it will be built with a foreign loan. KAIST, created by the Korean government in 1971 to drive the economic engine through advancement of science and technology with a six-million USD loan from USAID, has now become a donor institution that hands down science and technology education systems including the construction of campuses to underdeveloped countries.The successful case of KAIST has been benchmarked by many countries for years. For instance, KAIST set up the curriculum of the nuclear engineering program at the Khalifa University of Science and Technology in UAE in 2010. In China, Chongqing University of Technology is running its electrical engineering and computer science programs based on the educational systems and curricula offered by KAIST from 2015. In October, KAIST also signed an MOU with the Prince Mohammad Bin Salman College of Cyber Security, AI, and Advanced Technologies in Saudi Arabia to provide the undergraduate program for robotics.Among all these programs benchmarking KAIST, Kenya KAIST clearly stands out, for it is carrying out a turnkey-based project that encompasses every aspect of institution building ranging from educational curriculum development to campus construction and supervision.President Sung-Chul Shin is extremely excited about finalizing the deal, remarking, “It is of great significance that KAIST’s successful development model has carved out a unique path to becoming a global leading university that will benefit other countries. In only a half century, we have transitioned from a receiver to a donor institution, as the country itself has done.”“KAIST will spare no effort for Kenya KAIST to become a successful science and technology university that will play a crucial role in Kenya’s national development. I believe Kenya KAIST will be an exemplary case of an ODA (Official Development Assistance) project based on the development of science and technology to benefit underdeveloped countries,” he added.
2018.12.03 View 10597 -
From Concept to Reality: Changing Color of Light Using a Spatiotemporal Boundary
(from left: Professor Bumki Min, PhD candidate Jaehyeon Son and PhD Kanghee Lee)
A KAIST team developed an optical technique to change the color (frequency) of light using a spatiotemporal boundary. The research focuses on realizing a spatiotemporal boundary with a much higher degree of freedom than the results of previous studies by fabricating a thin metal structure on a semiconductor surface. Such a spatiotemporal boundary is expected to be applicable to an ultra-thin film type optical device capable of changing the color of light.
The optical frequency conversion device plays a key role in precision measurement and communication technology, and the device has been developed mainly based on optical nonlinearity.
If the intensity of light is very strong, the optical medium responds nonlinearly so the nonlinear optical phenomena, such as frequency doubling or frequency mixing, can be observed. Such optical nonlinear phenomena are realized usually by the interaction between a high-intensity laser and a nonlinear medium.
As an alternative method frequency conversion is observed by temporally modifying the optical properties of the medium through which light travels using an external stimulus. Since frequency conversion in this way can be observed even in weak light, such a technique could be particularly useful in communication technology.
However, rapid optical property modification of the medium by an external stimulus and subsequent light frequency conversion techniques have been researched only in the pertubative regime, and it has been difficult to realize these theoretical results in practical applications.
To realize such a conceptual idea, Professor Bumki Min from the Department of Mechanical Engineering and his team collaborated with Professor Wonju Jeon from the Department of Mechanical Engineering and Professor Fabian Rotermund from the Department of Physics. They developed an artificial optical material (metamaterial) by arranging a metal microstructure that mimics an atomic structure and succeeded in creating a spatiotemporal boundary by changing the optical property of the artificial material abruptly.
While previous studies only slightly modified the refractive index of the medium, this study provided a spatiotemporal boundary as a platform for freely designing and changing the spectral properties of the medium. Using this, the research team developed a device that can control the frequency of light to a large degree.
The research team said a spatiotemporal boundary, which was only conceptually considered in previous research and realized in the pertubative regime, was developed as a step that can be realized and applied.
Professor Min said, “The frequency conversion of light becomes designable and predictable, so our research could be applied in many optical applications. This research will present a new direction for time-variant media research projects in the field of optics.”
This research, led by PhD Kanghee Lee and PhD candidate Jaehyeon Son, was published online in Nature Photonics on October 8, 2018.
This work was supported by the National Research Foundation of Korea (NRF) through the government of Korea. The work was also supported by the Center for Advanced Meta-Materials (CAMM) funded by the Korea Government (MSIP) as the Global Frontier Project (NRF-2014M3A6B3063709).
Figure 1. The frequency conversion process of light using a spatiotemporal boundary.
Figure 2. The complex amplitude of light at the converted frequency with the variation of a spatiotemporal boundary.
2018.11.29 View 8447 -
KAIST Shows Strong Performance in Crypto Contest Korea 2018
(Awardees at the ceremony for Crypto Contest Korea 2018)
A paper titled “Indifferentiability of Truncated Random Permutations” by PhD candidate Wonseok Choi and MS candidate Byeonghak Lee (under Professor Jooyoung Lee) from the KAIST Graduate School of Information Security (GSIS) won first place in Crypto Contest Korea 2018. Byeonghak Lee became a repeat winner since his paper titled “Tweakable Block Ciphers Secure Beyond the Birthday Bound in the Ideal Cipher Model” also received an award at Crypto Contest Korea 2017.
The contest, hosted by the Korea Cryptography Forum, the Korea Institute of Information Security & Cryptology, and the National Security Research Institute and sponsored by the National Intelligence Service, was held for promoting cryptography in Korea. The total prize money is fifty million won with ten million won going to the first place winners.
The contest was divided into three divisions: paper, problem solving, and idea. Among the three divisions, first place came from the paper division only.
Besides first place, KAIST students showed outstanding performance in the contest. PhD candidate Seongkwang Kim received participation prize while he also received special prizes with MS candidate Yeongmin Lee. The hacking club GoN (under Professor Sang Kil Cha), comprised of undergraduate students from the GSIS was awarded the grand prize in the division of problem solving.
The award ceremony was held during the Future Crypto Workshop 2018 on November 15. The awards ceremony for Crypto Expert Korea 2018 were also held there, and PhD candidate Ji-Eun Lee from the School of Computing and Byeonghak Lee received awards, the grand prize and runner-up prize respectively.
2018.11.27 View 9020 -
Novel Strategies to Transform a Commercially Available Iboga Alkaloid to Post-Iboga Alkaloids
(PhD candidate HyeonggeunLim, Professor Sunkyu Han, PhD candidate Sikwang Seong)
KAIST chemists have synthesized seven different iboga and post-iboga natural products from commercially available catharanthine by mirroring nature’s biosynthetic post-modification of the iboga skeleton. They devised a novel strategy to biosynthesize the natural products via a series of selective and efficient oxidation and rearrangement reactions. This will serve as a stepping stone for developing therapeutic medications against cancer and narcotics addiction.
The research team, led by Professor Sunkyu Han, conceptualized and coined the term “Post-Iboga” alkaloids to describe the natural products that are biosynthetically derived from iboga-type alkaloids, which are composed of rearranged indole and/or isoquinuclidine backbones.
Iboga alkaloids have attracted significant attention from the scientific community due to their intriguing polycyclic structures and potential therapeutic uses against drug addictions. Nature has evolved to add architectural repertoires to this family of secondary metabolites by diversifying the iboga frameworks.
Notable examples are the FDA-approved anticancer drugs vinblastine and vincristine, both derived by the oxidative dimerization of catharanthine and vindoline subunits. Admittedly, synthetic foci toward the biosynthetic iboga-derivatives have historically been on these aforementioned dimeric natural products.
Recent natural product isolation studies on Tabernaemontana corymbosa and Ervatamia officinalis species have resulted in discoveries of various secondary metabolites that are biosynthetically derived from iboga alkaloids. These recent outbursts of iboga-derived natural product isolation reports have kindled interests toward these family of natural products.
The research team utilized (+)-catharanthine, the starting material for the industrial production of the anticancer drug Navelbine®. Well-orchestrated oxidations at the C19 position and the indole moiety of the catharanthine derivative, followed by differential rearrangements under acidic conditions, provided synthetic samples of voatinggine and tabertinggine respectively.
On the other hand, opportune oxidations at the C19 position and the alpha position of the tertiary amine moiety of the catharantine derivative, followed by a transhemiaminalization, produced the first synthetic sample of chippiine/dippinine-type natural product, dippinine B.
It is important to note that the chippiine and dippinine-type alkaloids have been targeted among synthetic chemists for over 30 years but had not succumbed to synthesis prior to this report.
Professor Han believes that their study will serve as a blueprint for further explorations of the synthesis, biosynthesis, and pharmacology of this emerging family of natural products. This study was published in Chem on November 15, 2018 (DOI: 10.1016/j.chempr.2018.10.009).
2018.11.16 View 5928 -
OUIC Presents the Six Most Promising Techs Transferrable to Local SMEs
KAIST will showcase the six most promising technologies for small and medium enterprises (SMEs) on November 14 in the Academic Cultural Complex. To strengthen the competitive edge of local SMEs in Daejeon, the Office of University-Industry made a survey of their technological needs and came up with the six most promising technologies. Developers will introduce their technologies during the session.Besides the introduction of the promising technologies, the session will also provide a program named University to Business (U2B) to match up technologies according to the SMEs’ needs. SMEs who wish to engage in technology transfers can receive counseling and other support programs during the session.First, Professor Seok-Hyung Bae from the Department of Industrial Design will present a technology for controlling cooperation robots. Professor Bae inserted flexible materials between the controllers to allow robots to use both hands stably and operate more accurately and swiftly. It can be applied to automatic robots, industrial robots, and service robots.Professor Hyun Myung from the Department of Civil & Environmental Engineering will demonstrate a robot navigation system in a dynamic indoor and outdoor environment, which can be applied to robotics in logistics, smart factories, and autonomous vehicles. Providing robust simultaneous localization and mapping systems, this technology shows high-performing navigation with low-cost sensors.Meanwhile, Professor Siyoung Choi from the Department of Chemical and Biomolecular Engineering will introduce a technology for forming stable adhesive emulsions. An emulsion is a stable mixture of water and oil. Conventionally, a small amount of surfactant is added to stabilize an emulsion. Here, Professor Choi developed a stable emulsion system without using any chemical substances. This technology can be applied to various fields, including the cosmetics, pharmaceutical, semiconductor, and painting industries. The session will also present smart IoTs platform technology developed by Professor Jinhong Yang from the KAIST Institute for IT Convergence. His technology minimizes errors occurring when multiple IoT devices are connected simultaneously. Professor Yong Keun Park from the Department of Physics will introduce a technology for measuring glycated hemoglobin by using the optical properties of red blood cells. This technology can be applied to make low-cost, small-sized measuring equipment. It can also be used for vitro diagnoses including diabetes, cardiovascular disorders, tumors, kidney disease, and infectious diseases. Professor Yong Man Ro from the School of Electrical Engineering will show technology for biometric access control. Conventional technologies for face recognition fall behind other biometrics. Professor Ro and his team developed a facial dynamics interpreting network which allows very accurate facial recognition by interpreting the relationships between facial local dynamics and estimating facial traits. This technology can be applied to security and communication in finance, computers, and information system.KAIST President Sung-Chul Shin said, “KAIST will continue to support SMEs to have stronger competitiveness in the market. Through technology transfer, we will drive innovation in technological commercialization where a university’s research and development creates economic value.”
2018.11.13 View 9613 -
Faster and More Powerful Aqueous Hybrid Capacitor
(Professor Jeung Ku Kang from the Graduate School of EEWS)
A KAIST research team made it one step closer to realizing safe energy storage with high energy density, high power density, and a longer cycle life. This hybrid storage alternative shows power density 100 times faster than conventional batteries, allowing it to be charged within a few seconds. Hence, it is suitable for small portable electronic devices.
Conventional electrochemical energy storage systems, including lithium-ion batteries (LIBs), have a high voltage range and energy density, but are subject to safety issues raised by flammable organic electrolytes, which are used to ensure the beneficial properties. Additionally, they suffer from slow electrochemical reaction rates, which lead to a poor charging rate and low power density with a capacity that fades quickly, resulting in a short cycle life.
On the other hand, capacitors based on aqueous electrolytes are receiving a great deal of attention because they are considered to be safe and environmentally friendly alternatives. However, aqueous electrolytes lag behind energy storage systems based on organic electrolytes in terms of energy density due to their limited voltage range and low capacitance.
Hence, developing aqueous energy storage with high energy density and a long cycle life in addition to the high power density that enables fast charging is the most challenging task for advancing next-generation electrochemical energy storage devices.
Here, Professor Jeung Ku Kang from the Graduate School of Energy, Environment, Water and Sustainability and his team developed an aqueous hybrid capacitor (AHC) that boasts high energy density, high power, and excellent cycle stability by synthesizing two types of porous metal oxide nanoclusters on graphene to create positive and negative electrodes for AHCs.
The porous metal oxide nanoparticles are composed of nanoclusters as small as two to three nanometers and have mesopores that are smaller than five nanometers. In these porous structures, ions can be rapidly transferred to the material surfaces and a large number of ions can be stored inside the metal oxide particles very quickly due to their small particle size and large surface area.
The team applied porous manganese oxide on graphene for positive electrodes and porous iron oxide on graphene for negative electrodes to design an aqueous hybrid capacitor that can operate at an extended voltage range of 2V.
Professor Kang said, “This newly developed AHC with high capacity and power density driven from porous metal oxide electrodes will contribute to commercializing a new type of energy storage system. This technology allows ultra-fast charging within several seconds, making it suitable as a power source for mobile devices or electric vehicles where solar energy is directly stored as electricity.”
This research, co-led by Professor Hyung Mo Jeong from Kangwon National University, was published in Advanced Functional Materials on August 15, 2018.
Figure 1. Image that shows properties of porous metal oxide nanoparticles formed on graphene in the aqueous hybrid capacitor
2018.11.09 View 7904 -
Team KAT Wins the Autonomous Car Challenge
(Team KAT receiving the Presidential Award)
A KAIST team won the 2018 International Autonomous Car Challenge for University Students held in Daegu on November 2.
Professor Seung-Hyun Kong from the ChoChunShik Graduate School of Green Transportation and his team participated in this contest with the team named KAT (KAIST Autonomous Technologies). The team received the Presidential Award with a fifty million won cash prize and an opportunity for a field trip abroad.
The competition was conducted on actual roads with Connected Autonomous Vehicles (CAV), which incorporate autonomous driving technologies and vehicle-to-everything (V2X) communication system.
In this contest, the autonomous vehicles were given a mission to pick up passengers or parcels. Through the V2X communication, the contest gave current location of the passengers or parcels, their destination, and service profitability according to distance and level of service difficulty.
The participating vehicles had to be equipped very accurate and robust navigation system since they had to drive on narrow roads as well as go through tunnels where GPS was not available. Moreover, they had to use camera-based recognition technology that was invulnerable to backlight as the contest was in the late afternoon.
The contest scored the mission in the following way: the vehicles get points if they pick up passengers and safely drop them off at their destination; on the other hand, points are deducted when they violate lanes or traffic lights. It will be a major black mark if a participant sitting in the driver’s seat needs to get involved in driving due to a technical issue.
Youngbo Shim of KAT said, “We believe that we got major points for technical superiority in autonomous driving and our algorithm for passenger selection.”
This contest, hosted by Ministry of Trade, Industry and Energy, was the first international competition for autonomous driving on actual roads. A total of nine teams participated in the final contest, four domestic teams and five teams allied with overseas universities such as Tsinghua University, Waseda University, and Nanyang Technological University.
Professor Kong said, “There is still a long way to go for fully autonomous vehicles that drive flexibly under congested traffic conditions. However, we will continue to our research in order to achieve high-quality autonomous driving technology.”
(Team KAT getting ready for the challenge)
2018.11.06 View 12525 -
Professor Baik Awarded Sangsan Young Mathematician Prize
(Professor Hyungryul Baik)
Professor Hyungryul Baik from the Department of Mathematical Sciences was honored as the recipient of the 2018 Sangsan Prize for Young Mathematicians by the Korean Mathematical Society (KMS).
The Sangsan Prize recognizes young mathematicians who finished their degree within the previous five years and have begun an outstanding research career. Professor Baik was recognized for his studies in the fields of low-dimensional topology, geophysical mathematics, and geometric theory. In particular, his Ph.D. dissertation presented a new criterion that completely identifies the hyperbolic surface group, making an inference about the nature of the hyperbolic manifold group.
Recently, Professor Baik co-published a paper entitled Spaces of Invariant Circular Orders of Groups with Professor Eric Samperton at the University of California Santa Barbara in the renowned academic journal Groups, Geometry, and Dynamics in 2018.
Professor Baik earned his BS at KAIST and finished his MS and Ph.D. in mathematics in 2014 at Cornell University. He joined KAIST as a faculty member last year.
2018.10.30 View 7131 -
KAIST Thanks Supporters for Building KAIST of Today
KAIST hosted its first Fundraising Gala on October 26, 2018. It was organized to demonstrate deep gratitude to those who have made contributions to KAIST, making it possible to progress every year.
The KAIST Development Foundation (KDF) endeavored to make a meaningful and inclusive event by collecting archives that show the history of donations while sending invitatio ns to all the members of KAIST, including donors and potential donors as well as professors and student representatives.
Approximately 200 distinguished guests attended the gala, including major donors, Chairperson of KDF Soo Young Lee and Chairman Beang Ho Kim, Former Minister of Science Dr. Geun Mo Jung, Former Minister of Science and Technology Woo Sik Kim, and KAIST alumni including the first Korean astronaut So-Yeon Yi.
(Student cheer leading club, ELKA)
At the gala, KAIST shared its 47 years of funding and an expenditure summary with major performances achieved from the year it was founded. According to the summary, KAIST has received more than 323.1 billion won since 1971. The total number of donors was 12,906 while the number of contribution reached 77,710.
Among the total funding (323.1 billion won), corporate gifts made up 43.1% of the total and individual gifts stood at 39.1%, showing that KAIST has received and is receiving support evenly from companies and individuals.
Taking a close look at the major donors, there is an interesting fact about KAIST’s fundraising culture. There has been continuous support from individuals who did not have any personal or academic ties with KAIST before donating. However, they have made large gifts to KAIST so that the best students in the fields of science and technology can be fostered for the sake of national development. The major donors included Young Han Kim (1999), Moon Soul Chung (2001), Byiung Joon Park (2007), Keun Chul Ryu (2008), Beong Ho Kim (2009), Chun Shik Cho and E won Oh (2010), Soo Young Lee (2012), Tae-won Chey (2014), Jeong Ja Cho (2015), and Chang Kun Sohn (2017).
Especially, M. S. Chung, B. H. Kim, C. S. Cho and S. Y. Lee made additional mega-gifts to KAIST, showing continuous support for KAIST’s development.
Nevertheless, the KAIST fundraising culture could not be created with major donors only. Among the total number of donors (12,906), alumni showed the strong engagement standing at 40.4% while parents and students were at 26.1% and 12.7% respectively. The contribution numbers follow the order of alumni (34.8%), parents (20.3%), staff (20%), professors (13.3%), and students (5.7%). These statistics imply that individual’s constant donations play a significant part in the fundraising culture of KAIST.
Additionally, engagement continues to rise every year, and it reached 12,039 gifts in 2017, which increased 5.7 times over ten years.
(from left: Executive Director of KDF Young-gul Kim KAIST President Sung-Chul Shin)
These valuable gifts are the vital fuel for KAIST’s progress. As of 2018, KAIST has spent 205.8 billion won: 81.9 billion won for construction and facilities operation, 79.7 billion won for academics and research, 39 billion won for academic management, and 5.2 billion won for scholarships.
The construction and facilities operation fund aided the evolution of physical infrastructure. KAIST endowed the ChungMoonSoul Building for promoting convergence between information and biotechnology, the Yang Bun Soon Building for bio and brain engineering studies, and the Chunghi & Byiung Jun Park KI Building for multi and interdisciplinary research. Their generous gifts built the foundation for KAIST taking off towards becoming a global leading university.
Meanwhile, the academic and research funds provided opportunities to professors and students to carry out creative research and academic missions. The academic management fund helped open new departments (i.e. The Cho Chun Shik Graduate School of Green Transportation and the Moon Soul Graduate School of Future Strategy) and their programs, for which their names came from the major donors.
(The first Korean astronaut So-Yeon Yi)
At the gala, special events were held for two exclusive moments that contributed to promoting and making a better image for KAIST to the public. One was the 10th anniversary of the space exploration of the first Korean astronaut Dr. Yi. The other was the 20th anniversary of the TV drama series, called ‘KAIST’ which was aired from 1999 to 2000. The writer and main casting crew members joined the event. They said that it was their first time to gather in one place after the show last aired and this event would be memorable for them as well.
President Sung-Chul Shin said, “These gifts play the role of seed money that helps KAIST obtain competence in a global scenario. I hope people have more interest in supporting KAIST through this event.”
1 Total Amount of Gift
2 Total Donors
3 Expenditure Number of Contribution
4 Expenditure
2018.10.29 View 8092 -
KAIST Launches Woorisae II
Professor Sejin Kwon from the Department of Aerospace Engineering and his team succeeded in launching a science rocket, named ‘Woorisae II’ at Saemanguem reclamation. This rocket was developed in collaboration with the Satellite Technology Research Lab (SaRTec).
The test-firing was conducted at 10:43 am on Sunday October 28, 2018 (35°N 42’ 06” 126°E 33’ 36”, Radius of 0.6NM). This launch was the follow-up to the previous launch that was cancelled due to not gaining approval for using the airspace.
Professor Kwon’s team put a great deal of effort into securing the land for the rocket launch. As a result, they got approval from the Saemangeum Development and Investment Agency for the land and the Ministry of Land, Infrastructure and Transport for the use of the airspace. The Republic of Korea Air Force and United States Air Force also approved the use of the airspace for the launch of the science rocket for research purposes.
Woorisae II is 2.2 meters long with a diameter of 20cm, and weighs 13kg without a payload. The rocket is powered by a hybrid rocket with hydrogen peroxide oxidizer producing 100 kg of force. The Woorisae II sounding rocket was designed to burn for five seconds and then continue inertial flight for 20 seconds. The target altitude of Woorisae II was set at 3,300 feet to comply with the airspace approval.
The team developed the core components, including a hybrid rocket propulsion system, flight computer and parachute recovery system, as well as a ground control station. The flight data was transmitted to the ground station and recorded to onboard computer memory.
When a malfunction occurs during the flight, Woorisae II was designed to terminate the power flight for safety by shutting the propellant valve and deploying the recovery parachute. All the rocket subsystems and components were developed and supplied by domestic startup companies such as INOCOM and NARA SPACE TEHCNOLOGY.
Generally, sounding rockets reach an altitude beyond 30km and are widely used for testing rocket engines and reentry materials as well as for conducting microgravity experiments. Instruments for atmospheric science can also be installed to measure fine dust and high altitude atmosphere. Besides these science and technology purposes, most advanced spacefaring countries have sounding rocket programs to train and educate young people in the field of space science.
Professor Kwon said, “We will plan to launch upgraded rockets on November 4 and December 6 because we already received approval from the related agencies for using this land and airspace. Based on the experiment, we are planning to develop a cost-efficient small launch vehicle that is capable of delivering a cube satellite into Earth’s orbit.”
(Photos of preparing the rocket launch)
2018.10.29 View 11108 -
Lens-free OLEDs with Efficiency comparable to that of Inorganic LEDs
(from left: Professor Seunghyup Yoo and PhD candidate Jinouk Song)
The use of organic light-emitting diodes (OLEDs) has extended to various applications, but their efficiency is still lagging behind inorganic light-emitting diodes. In this research, a KAIST team provided a systematic way to yield OLEDs with an external quantum efficiency (EQE) greater than 50% with an external scattering medium.
Having properties suitable for thin and flexible devices, OLEDs are popular light sources for displays, such as mobile devices and high quality TVs. In recent years, numerous efforts have been made to apply OLEDs in lighting as well as light sources for vehicles.
For such applications, high efficiency is of the upmost importance for the successful deployment of light sources. Thanks to continuous research and the development of OLEDs, their efficiency is steadily on the rise, and a level equivalent to inorganic LEDs has been demonstrated in some reports.
However, these highly efficient OLEDs were often achieved with a macroscopic lens or complex internal nanostructures, which undermines the key advantages of OLEDs as an affordable planar light sources and tends to hinder their stable operation, thus putting a limitation to their commercialization.
Among various methods proven effective for OLED light extraction, a team led by Professor Seunghyup Yoo at the School of Electrical Engineering focused on the external scattering-based approach, as it can maintain planar geometry and compatibility with flexibility. It is also able to be fabricated on a large scale at a low cost and causes no interference with electrical properties of OLEDs.
Conventionally, research on enhancing OLED light extraction using light scattering has been conducted empirically in many cases. This time, the team developed comprehensive and analytical methodology to theoretically predict structures that maximize efficiency.
Considering OLEDs with the external scattering layers as a whole rather than two separate entities, the researchers combined the mathematical description of the scattering phenomena with the optical model for light emission within an OLED to rapidly predict the characteristics of many devices with various structures. Based on this approach, the team theoretically predicted the optimal combination of scattering layers and OLED architectures that can lead to the maximum efficiency.
Following this theoretical prediction, the team experimentally produced the optimal light scattering film and incorporated it to OLEDs with orange emitters having a high degree of horizontal dipole orientation. As a result, the team successfully realized OLEDs exhibiting EQE of 56% and power efficiency of 221 lm/W. This is one of the highest efficiencies ever realized for an OLED unit device without the help of a macroscopic lens or internal light extraction structures.
Professor Yoo said, “There are various technologies developed for improving OLED light extraction efficiency; nevertheless, most of them have not reached a level of practical use. This research mainly provides a systematic way to attain an EQE of 50% or higher in OLEDs while keeping in mind the constraints for commercialization. The approach shown here can readily be applied to lighting devices or sensors of wearable devices.”.
This research, co-led by Professor Jang-Joo Kim from Seoul National University and Professor Yun-Hi Kim from Gyeongsang National University, was published in Nature Communications on August 10, 2018. (J. Song et al. Nature Communications, 9, 3207. DOI: 10.1038/s41467-018-05671-x)
Figure 1.Photographs of OLEDs with SiO₂ -embedded scattering layers according to scatterance
2018.10.26 View 9167 -
Washing and Enrichment of Micro-Particles Encapsulated in Droplets
Researchers developed microfluidic technology for the washing and enrichment of in-droplet micro-particles. They presented the technology using a microfluidic chip based on surface acoustic wave (SAW)-driven acoustic radiation force (ARF).
The team demonstrated the first instance of acoustic in-droplet micro-particle washing with a particle recovery rate of approximately 90 percent. They further extended the applicability of the proposed method to in-droplet particle enrichment with the unprecedented abilities to increase the in-droplet particle quantity and exchange the droplet dispersed phase.
This proposed method enabled on-chip, label-free, continuous, and selective in-droplet micro-particle manipulation. The team demonstrated the first instance of in-droplet micro-particle washing between two types of alternating droplets in a simple microchannel, proving that the method can increase the particle quantity, which has not been achieved by previously reported methods.
The study aimed to develop an in-droplet micro-particle washing and enrichment method based on SAW-driven ARF. When a droplet containing particles is exposed to an acoustic field, both the droplet and suspended particles experience ARF arising from inhomogeneous wave scattering at the liquid-liquid and liquid-solid interfaces. Unlike previous in-droplet particle manipulation methods, this method allows simultaneous and precise control over the droplets and suspended particles. Moreover, the proposed acoustic method does not require labelled particles, such as magnetic particles, and employs a simple microchannel geometry.
Microfluidic sample washing has emerged as an alternative to centrifugation because the limitations of centrifugation-based washing methods can be addressed using continuous washing processes. It also has considerable potential and importance in a variety of applications such as single-cell/particle assays, high-throughput screening of rare samples, and cell culture medium exchange.
Compared to continuous flow-based microfluidic methods, droplet-based microfluidic sample washing has been rarely explored due to technological difficulties. On-chip, in-droplet sample washing requires sample transfer across the droplet interface composed of two immiscible fluids. This process involves simultaneous and precise control over the encapsulated sample and droplet interface during the medium exchange of the in-droplet sample.
Sample encapsulation within individual microscale droplets offers isolated microenvironments for the samples. Experimental uncertainties due to cross-contamination and Taylor dispersion between multiple reagents can be reduced in droplet-based microfluidics.
This is the first research achievement made by the Acousto-Microfluidics Research Center for Next-Generation Healthcare, the cross-generation collaborative lab KAIST opened in May. This novel approach pairs senior and junior faculty members for sustaining the research legacy even after the senior researcher retires. The research center, which paired Chair Professor Hyung Jin Sung and Professors Hyoungsoo Kim and Yeunwoo Cho, made a breakthrough in microfluidics along with PhD candidate Jinsoo Park. The study was featured as the cover of Lab on a Chip published by Royal Society of Chemistry.
Jinsoo Park, first author of the study, believes this technology will may serve as an in-droplet sample preparation platform with in-line integration of other droplet microfluidic components. Chair Professor Sung said, “The proposed acoustic method will offer new perspectives on sample washing and enrichment by performing the operation in microscale droplets.”
Figure 1. (a) A microfluidic device for in-droplet micro-particle washing and enrichment; (b) alternatingly produced droplets of two kinds at a double T-junction; (c) a droplet and encapsulated micro-particles exposed to surface acoustic wave-driven acoustic radiation force; (d-h) sequential processes of in-droplet micro-particle washing and enrichment operation.
2018.10.19 View 8127