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Successful Synthesis of Gamma-Lanctam Rings from Hydrocarbons
(The team of Professor Chang, far right, at the Department of Chemistry)
KAIST chemists have designed a novel strategy to synthesize ring-shaped cyclic molecules, highly sought-after by pharmaceutical and chemical industries, and known as gamma-lactams. This study describes how these five-membered rings can be prepared from inexpensive and readily available feedstock hydrocarbons, as well as from complex organic molecules, such as amino acids and steroids.
Gamma-lactams find several applications in medicinal, synthetic, and material chemistry. For example, they are included in a large number of pharmaceutically active compounds with antibiotic, anti-inflammatory, and anti-tumoral functions. This research was published in Science on March 2.
Conversion of hydrocarbons into nitrogen-containing compounds is an important area of research, where the challenge lies in breaking strong carbon-hydrogen (C−H) bonds, and converting them into carbon-nitrogen (C–N) bonds in a controlled fashion. For this reason, hydrocarbons are difficult to use as starting materials, albeit the fact that they exist in large quantities in nature.
Over the last 35 years, chemists have found ways of converting simple hydrocarbons into nitrogen-containing rings, such as indoles or pyrrolidines, but gamma-lactams proved impossible to prepare using the same approaches. Researchers hypothesized that such failure was due to alternative chemical pathways that steer the reaction away from the wanted rings: The reaction intermediate (carbonylnitrene) quickly breaks down into unsought products. Using computer models of the desired and undesired reaction pathways, the team found a strategy to completely shut down the latter in order to obtain the longed-for gamma-lactams. For the first time, these four carbons and one nitrogen cyclic molecules were obtained directly from simple feedstock chemicals.
Led by Professor Chang Sukbok at the Department of Chemistry, the team designed the winning reaction with the help of computer simulations that analyze the reaction mechanisms and calculate the energy required for the reaction to take place. According to such computer predictions, the reaction could follow three pathways, leading to the formation of either the desired gamma-lactam, an unwanted product (isocyanate), or the degradation of the catalyst caused by the substrate reacting with the catalyst backbone. Combining experimental observations and detailed computer simulations, the team designed an iridium-based catalyst, highly selective for the gamma-lactam formation. In this way, the two undesired pathways were systematically shut down, leaving the formation of the nitrogen-containing ring as the only possible outcome. Professor Chang is also in charge of the Center for Catalytic Hydrocarbon Functionalizations at the Institute for Basic Science (IBS).
“With this work we offer a brand new solution to a long-standing challenge and demonstrate the power of what we call mechanism-based reaction development,” explains Professor Baik Mu-Hyun, a corresponding author of the study.
Beyond using cheap feedstock hydrocarbons as substrates, the team was also successful in converting amino acids, steroids, and other bio-relevant molecules into gamma-lactams, which might find a variety of applications as plant insecticide, drugs against parasitic worms, or anti-aging agents. This new synthetic technology gives much easier access to these complicated molecules and will enable the development of potential drugs in a much shorter amount of time at a lower cost.
Figure 1: Selective amidation reaction using newly designed iridium (Ir) catalysts. Abundant in nature Hydrocarbons are used as substrates to synthesize nitrogen-containing ring, called gamma-lactams.
Figure 2: Three possible reaction pathways and energy barriers predicted by computational chemistry. The scientists developed new iridium-based catalysts that are highly selective for the C–H insertion pathway which leads to the desired gamma-lactam molecules.
Figure 3: Interesting gamma-lactams derived from natural and unnatural amino acids, steroids, etc., which may be used to protect plants against insects, fight parasitic worms, or as anti-aging agents.
2018.03.02 View 9116 -
Aqueous Storage Device Needs Only 20 Seconds to Go
(from left: PhD candidate Il Woo Ock and Professor Jeung Ku Kang)
A KAIST research team developed a new hybrid energy storage device that can be charged in less than half a minute. It employs aqueous electrolytes instead of flammable organic solvents, so it is both environmentally friendly and safe. It also facilitates a boosting charge with high energy density, which makes it suitable for portable electronic devices.
Professor Jeung Ku Kang and his team from the Graduate School of Energy, Environment, Water, and Sustainability developed this hybrid energy storage with high energy and power densities along over a long cycle life by assembling fibre-like polymer chain anodes and sub-nanoscale metal oxide cathodes on graphene.
Conventional aqueous electrolyte-based energy storage devices have a limitation for boosting charges and high energy density due to low driving voltage and a shortage of anode materials.
Energy storage device capacity is determined by the two electrodes, and the balance between cathode and anode leads to high stability. In general, two electrodes show differences in electrical properties and differ in ion storage mechanism processes, resulting in poor storage and stability from the imbalance.
The research team came up with new structures and materials to facilitate rapid speed in energy exchange on the surfaces of the electrodes and minimize the energy loss between the two electrodes.
The team made anodes with graphene-based polymer chain materials. The web-like structure of graphene leads to a high surface area, thereby allowing higher capacitance.
For cathode materials, the team used metal oxide in sub-nanoscale structures to elevate atom-by-ion redox reactions. This method realized higher energy density and faster energy exchange while minimizing energy loss.
The developed device can be charged within 20 to 30 seconds using a low-power charging system, such as a USB switching charger or a flexible photovoltaic cell. The developed aqueous hybrid energy device shows more than 100-fold higher power density compared to conventional aqueous batteries and can be rapidly recharged. Further, the device showed high stability with its capacity maintained at 100% at a high charge/discharge current.
Professor Kang said, “This eco-friendly technology can be easily manufactured and is highly applicable. In particular, its high capacity and high stability, compared to existing technologies, could contribute to the commercialization of aqueous capacitors. The device can be rapidly charged using a low-power charging system, and thus can be applied to portable electronic device.”
This research, led by a PhD candidate Il Woo Ock, was published in Advanced Energy Materials on January 15.
Figure 1. Switching wearable LED kit with two AHCs in series charged by a flexible photovoltaic cell
Figure 2. Schematic diagram for aqueous hybrid capacitors
Figure 3. TEM images of anode and cathode
2018.02.28 View 13089 -
Samsung Electronics' Chairman Kwon Becomes the First Alumnus Honorary Doctorate
(Samsung Electronics' Chairman & CEO Kwon,left, and President Shin)
The semiconductor has bred innovation in Korea, as one of the staples of economic growth. Without the success of the semiconductor industry of Korea, it is hard to imagine the high tech dominance in the global market enjoyed by Korean companies.
It is said that one in every four Ph.D.s working in the semiconductor industry of Korea graduated from KAIST. Among them, Chairman and CEO Oh-Hyun Kwon of Samsung Electronics, Class of 1977, has arrived at the epitome of this top industry.
KAIST’s class of 1977 produced many movers and shakers in Korea’s innovation efforts. Now in their mid-60s, they were the players who embodied Korea’s ICT and helped it become a global powerhouse. They are the ones who worked for and witnessed the socio-economic transformation of Korea through innovation.
In recognition of his unsurpassable entrepreneurship, which made the remarkable strides in the semiconductor and electronics industry in Korea and beyond, Chairman Kwon was honored as the first recipient of an honorary doctorate from his alma mater on February 23 during the 2018 commencement ceremony.
After completing his Master's in Electrical Engineering at KAIST in 1977, he earned his Ph.D. in Electrical Engineering from Stanford University. The first honorary degree bestowed to an alumnus was conferred by the first alumnus President of KAIST Sung-Chul Shin. President Shin said that Chairman Kwon’s exceptional leadership has inspired the KAIST community and exemplified the spirit of KAIST.
Currently serving as chairman & CEO of Samsung Electronics and Samsung Advanced Institute of Technology (SAIT), Kwon has worked for Samsung in a variety of key positions in their semiconductor division since 1985.
In the mid-1980s, Japan was leading the global semiconductor market. At Samsung, Chairman Kwon, who was in charge of the memory semiconductor team, successfully developed 4M DRAM. Later in 1992, he played a leading role in the development of the world’s first 64M DRAM.
The success of 4M DRAM and 64M DRAM led Samsung to clinch the top position in the DRAM and NAND flash business around the world. This helped Samsung emerge as a global leader in the semiconductor industry.
As a result, Samsung, as well as the national economy, could gain significant momentum to build national competitiveness and economic growth. The outstanding technological leadership of Chairman Kwon led to the development of proprietary semiconductor design and processes technologies as well as numerous patents.
He also played a leadership role in creating a mutual growth environment among conglomerates rather than merely engaging in direct competition. Chairman Kwon made every effort to establish the cornerstone of mutual growth, especially in relationships with small and medium-sized enterprises (SMEs). His win-win collaboration initiatives among conglomerates and SMEs made a significant impact on the development of the entire industry of Korea.
In his acceptance speech, he charged the graduates to embrace challenges, to collaborate with peers, and create their own future.
The full text of his speech is printed below.
Graduates and distinguished guests! I extend my sincere congratulations to my fellow graduates, as you are awarded degrees for your deep efforts, as well as to the parents and family members who have supported you.
In 1977, I received my Master’s degree in Electrical Engineering from KAIST. Today, as the first honorary doctor among KAIST graduates, I am truly honored to be here. I am deeply grateful to all of you, including President Sung-Chul Shin and the Chairman of the Board of Trustees, Jang-Moo Lee.
Today, I want to tell you about the experiences and lessons I have learned from my 40 years of corporate management experience.
First, you should lead and drive changes by yourself. In the process of realizing a dream, the situation and circumstances do not always proceed as you planned.
I started my career as a researcher. However, I had to continuously transform myself into a project leader, business team leader, and CEO. It was challenging every time, due to a lack of preparing and my insufficient ability. However, I have always accomplished the intended goal through the mindset of embracing changes and studying new things.
It is said that the survivors are not always the strongest nor the most intelligent, but the ones who are the most adaptive to changes. We can only be the last survivor if we have the character to see those small signs that signal changes are coming and cope with changes well. Take changes positively and actively and then, transform yourself to match a given situation.
In addition, it is important to understand others. When it comes to one’s career, there is nothing that you can do alone without the assistance of others. If it is not possible to do everything by yourself, you will need to supplement your efforts through the help of others. To do this, you need to understand your colleagues, bosses, and customers first.
People, who work in tech tend to cage themselves in their own silos. But in an era of destructive innovation, where boundaries of industries and technologies are collapsing at a breakneck pace, scientists also need to enhance their understanding of various areas such as culture, art, and the humanities.
This is a famous verse from a poem by Chun-Soo Kim.
Before I called his name,
He was nothing but a gesture.
When I called his name, He came to me and became a flower.
Make wonderful synergy by making your partner a flower and complementing each other. When you first notice the true value of another person and interact with them, the value of the individual will be doubled and will bring about a greater impact.
Finally, we all need to cooperate with each other. All of you here, including myself, are people who have benefited from society. We must cooperate with each other and give back to society for the best results.
A biologist once said that incremental evolution comes from competition, but fundamental evolution comes from cooperation. Great leaders should achieve results through cooperation rather than competition.
You are the future leaders with top-class knowledge. I hope you will become great leaders who have wisdom that combines external resources with your abilities.
Now, graduates of 2018 who are standing at the starting line, we often worry about an unpredictable tomorrow. However, the smartest way to predict the future is to create the future for ourselves. Moreover, we can try again even though we sometimes make mistakes. I urge you to make future you are hoping for.
Once again, I would like to thank you for this honorary doctorate and extend my sincere wishes for the endless development of KAIST and the best of luck to the futures of these graduates. Thank you.
2018.02.26 View 8708 -
Soul-Searching & Odds-Defying Determination: A Commencement Story of Dr. Tae-Hyun Oh
(Dr. Tae-Hyun Oh, one of the 2736 graduates of the 2018)
Each and every one of the 2,736 graduates has come a long way to the 2018 Commencement. Tae-Hyun Oh, who just started his new research career at MIT after completing his Ph.D. at KAIST, is no exception.
Unlike the most KAIST freshmen straight out of the ingenious science academies of Korea, he is among the many who endured very challenging and turbulent adolescent years. Buffeted by family instability and struggling during his time at school, he saw himself trapped by seemingly impenetrable barriers. His mother, who hated to see his struggling, advised him to take a break to reflect on who he is and what he wanted to do.
After dropping out of high school in his first year, ways to make money and support his family occupied his thoughts. He took on odd jobs from a car body shop to a gas station, but the real world was very tough and sometimes even cruel to the high school dropout.
Bias and prejudice stigmatizing dropouts hurt him so much. He often overheard a parent who dropped by the body shop that he worked in saying, “If you do not study hard, you will end up like this guy.” Hearing such things terrified him and awoke his sense of purpose. So he decided to do something meaningful and be a better man than he was.
“I didn’t like the person I was growing up to become. I needed to find myself and get away from the place I was growing up. It was my adventure and it was the best decision I ever made,” says Oh.
After completing his high school diploma national certificate, he planned to apply to an engineering college. On his second try, he gained admission into the Department of Electrical Engineering at Kwang Woon University with a full scholarship. He was so thrilled for this opportunity and hoped he could do well at college. Signal processing and image processing became the interest of his research and he finished his undergraduate degree summa cum laude.
Gaining confidence in his studies, he searched around graduate school department websites in Korea to select the path he was interested in. Among others, the Robotics and Computer Vision Lab of Professor In-So Kweon at the Department of Electrical Engineering at KAIST was attractive to him.
Professor Kweon’s lab is globally renowned for robot vision technology. Their technologies were applied into HUBO, the KAIST-developed bimodal humanoid robot that won the 2015 DARPA Challenges.
“I am so appreciate of Professor Kweon, who accepted and guided me,” he said. Under Professor Kweon’s advising, he could finish his Master’s and Ph.D. courses in seven years. The mathematical modeling on fundamental computer algorithms became his main research topic.
While at KAIST, his academic research has blossomed. He won a total of 13 research prizes sponsored by corporations at home and abroad such as Kolon, Samsung, Hyundai Motors, and Qualcomm.
In 2015, he won the Microsoft Research Asia Fellowship as the sole Korean among 13 Ph.D. candidates in the Asian region. With the MSRA fellowship, he could intern at the MS Research Beijing Office for half a year and then in Redmond, Washington in the US.
“Professor Kweon’s lab filled me up with knowledge. Whenever I presented our team’s paper at an international conference, I was amazed by the strong interest shown by foreign experts, researchers, and professors. Their strong support and interest encouraged me a lot. I was fully charged with the belief that I could go abroad and explore more opportunities,” he said.
Dr. Oh, who completed his dissertation last fall, now works at the Department of Electrical Engineering and Computer Science at MIT under Professor Wojciech Matusik.
“I think the research environment at KAIST is on par with MIT. I have very rich resources for my studies and research at both schools, but at MIT the working culture is a little different and it remains a big challenge for me. I am still not familiar with collaborative work with colleagues from very diverse backgrounds and countries, and to persuade them and communicate with them is very tough. But I think I am getting better and better,” he said.
Oh, who is an avid computer game player as well, said life seems to be a game. The level of the game will be upgraded to the next level after something is accomplished. He feels great joy when he is moving up and he believes such diverse experiences have helped him become a better person day by day. Once he identified what gave him a strong sense of purpose, he wasn’t stressed out by his studies any more. He was so excited to be able to follow his passion and is ready for the next challenge.
2018.02.23 View 12073 -
KAIST to Develop Technology to Control Topological Defects
(Professor Chan-Ho Yang and PhD candidate Kwang-Eun Kim)
Professor Chan-Ho Yang and his team from the Department of Physics developed technology to create and remove topological defects in ferroelectric nanostructures.
This technology will contribute to developing topological defect-based storage that will allow the saving of massive amounts of information in a stable manner.
Topology refers to the property of matter upon deformation, in which a circle and a triangle are considered to be the same topologically.
During the announcement of the 2016 Nobel Prize in Physics, the concept of topology was explained with a bagel with a hole, cinnamon bread without a hole, and a glass cup. Although the cinnamon bread and the glass cup have different appearances, they are topologically the same since neither has a hole. In the same sense, the bagel and the cinnamon bread are topologically different.
In other words, topology of matter is conserved and its properties cannot be altered by continuous deformation.
Using this topological texture can produce information storage devices that can protect the stored information from external stimuli, but the data can still be written and erased, resulting in ideal non-volatile memory.
Unlike ferroelectrics, magnetic topological defect structures such as the ferromagnetic vortex and skyrmion have already been implemented.
Ferroelectrics, which have aligned electric dipoles without external electric fields, can stabilize topological defect structures to a smaller size using less energy; however, further research on ferroelectrics has not been carried out sufficiently. This is due to a lack of research on stabilizing topological defect structures and how to control them in an experimental setting.
To overcome this problem, the team applied inhomogeneous deformations to ferroelectric nanostructures to successfully stabilize the topological defect structures. The team manufactured a ferroelectric nanoplate structure on a special board, which can exert strong compression from the bottom surface while the sides and the upper surfaces of the structure is free from deformation.
This structure led to radial compressive strain relaxation, in which deformations of the lattice stabilize the vortex structure of ferroelectrics.
This could lead to the establishment of the core principle of topological ferroelectric memory of high density, high efficiency, and high stability.
Professor Yang said, “Ferroelectrics are nonconductor but topological ferroelectric quasiparticles could carry electrical conductivity locally. This finding could be expanded to new quantum device research.”
This research, led by the PhD candidate Kwang-Eun Kim, was published in Nature Communications on January 26.
The study was co-conducted by Professor Si-Young Choi and Dr. Tae Yeong Koo from POSTECH, Professor Long-Qing Chen from The Pennsylvania State University, and Professor Ramamoorthy Ramesh from the University of California at Berkeley.
Figure 1. Five different topological structures produced by controlling the number of topological defects
2018.02.19 View 8059 -
Professor Hojong Chang Wins the Best Paper Award at ISIITA 2018
Professor Hojong Chang from the KAIST Institute won the best paper award at the International Symposium on Innovation in Information Technology and Application (ISIITA) 2018.
ISIITA is a global networking symposium in which leading researchers in the field of information technology and applications gather to exchange knowledge on technological convergence.
Professor Chang won the prize for his paper, titled ‘A Study on the Measurement of Aptamer in Urine Using SiPM’.
This paper proposes using aptamer to measure and analyze the density of sodium and potassium contained in urine, allowing diseases to be diagnosed in advance.
Professor Chang said, “With a point-of-care test system that facilitates a quick diagnosis without extra processes, such as centrifugation, it is possible to get an early diagnosis and check infection in real time. Through generalizing this crucial technology, we expect to develop adequate technology for enhancing quality of life.
2018.02.12 View 9091 -
Finding Human Thermal Comfort with a Watch-type Sweat Rate Sensor
(from left: Professor Young-Ho Cho and Researcher SungHyun Yoon)
KAIST developed a watch-type sweat rate sensor. This subminiature device can detect human thermal comfort accurately and steadily by measuring an individual’s sweat rate.
It is natural to sweat more in the summer and less in the winter; however, an individual’s sweat rate may vary in a given environment. Therefore, sweat can be an excellent proxy for sensing core body temperature.
Conventional sweat rate sensors using natural ventilation require bulky external devices, such as pumps and ice condensers. They are usually for physiological experiments, hence they need a manual ventilation process or high power, bulky thermos-pneumatic actuators to lift sweat rate detection chambers above skin for continuous measurement. There is also a small sweat rate sensor, but it needs a long recovery period.
To overcome these problems, Professor Young-Ho Cho and his team from the Department of Bio and Brain Engineering developed a lightweight, watch-type sweat sensor. The team integrated miniaturized thermos-pneumatic actuators for automatic natural ventilation, which allows sweat to be measured continuously.
This watch-type sensor measures sweat rate with the humidity rising rate when the chamber is closed during skin contact. Since the team integrated thermos-pneumatic actuators, the chamber no longer needs to be separated manually from skin after each measurement in order for the chamber to ventilate the collected humidity.
Moreover, this sensor is wind-resistant enough to be used for portable and wearable devices. The team identified that the sensor operates steadily with air velocity ranging up to 1.5m/s, equivalent to the average human walking speed.
Although this subminiature sensor (35mm x 25mm) only weighs 30 grams, it operates continuously for more than four hours using the conventional wrist watch batteries.
The team plans to utilize this technology for developing a new concept of cognitive air-conditioning systems recognizing Human thermal status directly; while the conventional air-conditioning systems measuring air temperature and humidity.
Professor Cho said, “Our sensor for human thermal comfort monitoring can be applied to customized or smart air conditioners. Furthermore, there will be more demands for both physical and mental healthcare, hence this technology will serve as a new platform for personalized emotional communion between humans and devices.”
This research, led by researchers Jai Kyoung Sim and SungHyun Yoon, was published in Scientific Reports on January 19, 2018.
Figure1. The fabricated watch-type sweat rate sensor for human thermal comfort monitoring
Figure 2. Views of the watch-type sweat rate sensor
Figure 3. Operation of the watch-type sweat rate sensor
2018.02.08 View 9073 -
KAIST to Host the THE Innovation & Impact Summit in 2019
KAIST and Times Higher Education (THE) agreed to co-host the THE Innovation & Impact Summit at KAIST from April 1 to 3, 2019.
Global leaders from higher education, government, and industry will gather at KAIST to discuss how universities can better innovate for creating a greater impact.
(from left: THE Managing Director Trevor Barratt and KAIST President Sung-Chul Shin)
President Sung-Chul Shin and Trevor Barratt, managing director at the THE, signed an agreement to host the 2019 THE Innovation & Impact Summit at KAIST next April. The agreement was signed on February 6 during the THE Asia Universities Summit held at SUSTech in Shenzhen in China. Phil Baty, editorial director at the THE was also present during the agreement.
By hosting the 2019 THE Innovation & Impact Summit, KAIST has a chance to introduce its innovative research and performance and its educational environment and startup ecosystem to the world. Having educational and industrial leaders meet at KAIST will add more power to the global status and capacity of KAIST.
The THE Innovation & Impact Summit, first held in 2017, is one in the seven presidential summit series held by THE. During the second summit at KAIST, THE will launch their world university innovation rankings for the first time.
As innovation at universities and its impact have been a crucial indicator in building an institutional brand and reputation, leading universities are gearing up to encourage startups and entrepreneurship education. Even more, innovation at universities is emerging as one of the growth engines of economies.
The innovation indicators of KAIST have been highly recognized by many global ranking institutions in terms of the volume of patents and the patents-to-article citation impact. Thomson Reuters has recognized KAIST for two consecutive years as the most innovative university in Asia, and sixth in the world.
President Shin has high expectations for the hosting of the Innovation & Impact Summit at KAIST. He explained, “Innovation makes up the DNA of KAIST and it has been our institutional mission from the start in 1971. KAIST was commissioned to make innovation for industrialization and economic development through education and research. I do not see any university more suitable than KAIST to host this innovation summit. I hope the summit at KAIST will serve as a global platform to provide very creative ideas for making innovation and collaboration among the leading universities for all the participants.”
Meanwhile, at the THE Asia Universities Summit in Shenzhen, how to respond to the implications of the Fourth Industrial Revolution was the key agenda piercing the two-day sessions.
As a panelist, President Shin shared his experiences on innovative strategies viable for spearheading university reform for the Fourth Industrial Revolution, along with Vice-Chancellor of the University of Sheffield Sir Keith Burnett, President of Monash University Margaret Gardner, and President of Hong Kong Polytechnic University President Timothy W. Tong. He said that universities should foster young talents by equipping them with creativity, collaboration, and convergent minds. To swiftly respond to the new industrial environment, President Shin said that universities should remove the high barriers between departments and establish cross- and inter-disciplinary education systems, convergence research and technology commercialization.
2018.02.06 View 10034 -
Developing Flexible Vertical Micro LED
A KAIST research team led by Professor Keon Jae Lee from the Department of Materials Science and Engineering and Professor Daesoo Kim from the Department of Biological Sciences has developed flexible vertical micro LEDs (f-VLEDs) using anisotropic conductive film (ACF)-based transfer and interconnection technology. The team also succeeded in controlling animal behavior via optogenetic stimulation of the f-VLEDs.
Flexible micro LEDs have become a strong candidate for the next-generation display due to their ultra-low power consumption, fast response speed, and excellent flexibility. However, the previous micro LED technology had critical issues such as poor device efficiency, low thermal reliability, and the lack of interconnection technology for high-resolution micro LED displays.
The research team has designed new transfer equipment and fabricated a f-VLED array (50ⅹ50) using simultaneous transfer and interconnection through the precise alignment of ACF bonding process. These f-VLEDs (thickness: 5 ㎛, size: below 80 ㎛) achieved optical power density (30 mW/mm2) three times higher than that of lateral micro LEDs, improving thermal reliability and lifetime by reducing heat generation within the thin film LEDs.
These f-VLEDs can be applied to optogenetics for controlling the behavior of neuron cells and brains. In contrast to the electrical stimulation that activates all of the neurons in brain, optogenetics can stimulate specific excitatory or inhibitory neurons within the localized cortical areas of the brain, which facilitates precise analysis, high-resolution mapping, and neuron modulation of animal brains. (Refer to the author’s previous ACS Nano paper of “Optogenetic Mapping of Functional Connectivity in Freely Moving Mice via Insertable Wrapping Electrode Array Beneath the Skull.” )
In this work, they inserted the innovative f-VLEDs into the narrow space between the skull and the brain surface and succeeded in controlling mouse behavior by illuminating motor neurons on two-dimensional cortical areas located deep below the brain surface.
Professor Lee said, “The flexible vertical micro LED can be used in low-power smart watches, mobile displays, and wearable lighting. In addition, these flexible optoelectronic devices are suitable for biomedical applications such as brain science, phototherapeutic treatment, and contact lens biosensors.”
He recently established a startup company ( FRONICS Inc. ) based on micro LED technology and is looking for global partnerships for commercialization. This result entitled “ Optogenetic Control of Body Movements via Flexible Vertical Light-Emitting Diodes on Brain Surface ” was published in the February 2018 issue of Nano Energy.
Figure 1. Comparison of μ-LEDs Technology
2018.01.29 View 13998 -
Easier Way to Produce High Performing, Flexible Micro-Supercapacitor
(Professor Minyang Yang and PhD Student Jae Hak Lee)
Professor Minyang Yang from the Department of Mechanical Engineering and his team developed a high-energy, flexible micro-supercapacitor in a simple and cost-effective way.
Compared to conventional micro-batteries, such as lithium-ion batteries, these new batteries, also called supercapacitors, are significantly faster to charge and semi-permanent.
Thin, flexible micro-supercapacitors can be a power source directly attached to wearable and flexible electronics.
However, fabrication of these micro-supercapacitors requires a complex patterning process, such as lithography techniques and vacuum evaporation. Hence, the process requires expensive instruments and toxic chemicals.
To simplify the fabrication of micro-supercapacitors in an eco-friendly manner, the team developed laser growth sintering technology. This technology manufactures superporous silver electrodes and applies them to the supercapacitors’ electrodes.
The team used a laser to form micro-patterns and generated nanoporous structures inside. This laser-induced growth sintering contributed to shortening the manufacturing process from ten steps to one.
Moreover, the team explored this unique laser growth sintering process –nucleation, growth, and sintering –by employing a particle-free, organometallic solution, which is not costly compared to typical laser-sintering methods for metallic nanoparticle solutions used in the printing of micro-electrodes.
Finally, unlike the typical supercapacitors comprised of a single substance, the team applied an asymmetric electrode configuration of nanoporous gold and manganese dioxide, which exhibits a highly-specific capacitance, to operate at a high voltage.
This method allows the team to develop energy storage with a high capacity. This developed micro-supercapacitor only requires four seconds to be charged and passed more than 5,000 durability tests.
Professor Yang said, “This research outcome can be used as energy storage installed in wearable and flexible electronic devices. Through this research, we are one step closer to realizing a complete version of flexible electronic devices by incorporating a power supply.”
This research, led by PhD candidate Jae Hak Lee, was selected as the cover of Journal of Materials Chemistry A on December 21, 2017.
Figure 1. Cover of the Journal Materials Chemistry A
Figure 2. Manufactured micro-supercapacitor and its performance
Figure 3. Laser growth sintering mechanism
Figure 4. Structural change of the silver conductor according to the irradiated laser energy
2018.01.18 View 8429 -
A Parallel MRI Method Accelerating Imaging Time Proposed
KAIST researchers proposed new technology that reduces MRI (magnetic resonance imaging) acquisition time to less than a sixth of the conventional method. They made a reconstruction method using machine learning of multilayer perception (MLP) algorithm to accelerate imaging time.
High-quality image can be reconstructed from subsampled data using the proposed method. This method can be further applied to various k-space subsampling patterns in a phase encoding direction, and its processing can be performed in real time.
The research, led by Professor Hyun Wook Park from the Department of Electrical Engineering, was described in Medical Physics as the cover paper last December. Ph.D. candidate Kinam Kwon is the first author.
MRI is an imaging technique that allows various contrasts of soft tissues without using radioactivity. Since MRI could image not only anatomical structures, but also functional and physiological features, it is widely used in medical diagnoses. However, one of the major shortcomings of MRI is its long imaging time. It induces patients’ discomfort, which is closely related to voluntary and involuntary motions, thereby deteriorating the quality of the MR images. In addition, lengthy imaging times limit the system’s throughput, which results in the long waiting times of patients as well as the increased medical expenses.
To reconstruct MR images from subsampled data, the team applied the MLP to reduce aliasing artifacts generated by subsampling in k-space. The MLP is learned from training data to map aliased input images into desired alias-free images. The input of the MLP is all voxels in the aliased lines of multichannel real and imaginary images from the subsampled k-space data, and the desired output is all voxels in the corresponding alias-free line of the root-sum-of-squares of multichannel images from fully sampled k-space data. Aliasing artifacts in an image reconstructed from subsampled data were reduced by line-by-line processing of the learned MLP architecture.
Reconstructed images from the proposed method are better than those from compared methods in terms of normalized root-mean-square error. The proposed method can be applied to image reconstruction for any k-space subsampling patterns in a phase encoding direction. Moreover, to further reduce the reconstruction time, it is easily implemented by parallel processing.
To address the aliasing artifact phenomenon, the team employed a parallel imaging technique using several receiver coils of various sensitivities and a compressed sensing technique using sparsity of signals.
Existing methods are heavily affected by sub-sampling patterns, but the team’s technique is applicable for various sub-sampling patterns, resulting in superior reconstructed images compared to existing methods, as well as allowing real-time reconstruction.
Professor Park said, "MRIs have become essential equipment in clinical diagnosis. However, the time consumption and the cost led to many inconveniences." He continued, "This method using machine learning could greatly improve the patients’ satisfaction with medical service." This research was funded by the Ministry of Science and ICT.
(Firgure 1. Cover of Medical Physics for December 2017)
(Figure 2. Concept map for the suggested network)
(Figure 3. Concept map for conventional MRI image acquisition and accelerated image acquisiton)
2018.01.16 View 6825 -
Harnessing the Strength of KAIST Alumni: New Head of KAA Inaugurated
KAIST alumni gathered in Seoul on January 13 to celebrate the New Year and the newly-elected leadership of the KAIST Alumni Association (KAA). More than 300 alumni, including President Sung-Chul Shin who is also an alumnus of KAIST, joined the gala event held at the Lotte Hotel.
Photo: Ki-Chul Cha(left) and Jung Sik Koh(right)
The KAA inaugurated its new president, Ki-Chul Cha, who was preceded by Jung Sik Koh, the former CEO at the Korea Resources Corporation. His term starts from January 2018 to December 2020.
Cha is the CEO of Inbody Co Ltd., a global company specializing in developing and selling medical instruments, such as a body composition analyzers, and medical solutions. He is also an adjunct professor in the Department of Mechanical Engineering at Yonsei University. Cha obtained a master’s degree in Mechanical Engineering at KAIST in 1980, and a Ph.D. in Bioengineering at the University of Utah, before finishing his post-doc fellowship at Harvard Medical School.
Cha plans to explore the idea that alumni engagement, saying, “KAIST stays as a home in the memories of 60,000 alumni. I will dedicate myself to stimulating the alumni association to make KAISTians proud.”
At the gala event, the KAA awarded the Alumni of the Year honor to six alumni who distinguished themselves in the areas of professional achievement, humanitarianism, and public service. They are the Director of Startup KAIST Professor Byoung Yoon Kim; President of LG Chem Ltd and Head of Battery Research and Development Myung Hwan Kim; Director of INNOX Advanced Materials Co., Ltd Kyung Ho Chang; Vice President of the Korea International Trade Association Jung-Kwan Kim; CEO of Samsung Electro-Mechanics Yun-Tae Lee; and CEO of ENF Technology Jinbae Jung.
Photo: President Shin(far right) poses with six awardees of the Distinguished Alumni Award and the former President of KAA, Koh(far left)
2018.01.16 View 11671