KAI
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COVID-19 Update: All Undergrad Housing Closed
KAIST stepped up preventive measures against the outbreak of COVID-19 by closing all housing complexes for undergraduate students.
Provost Kwang-Hyung Lee, in an email to KAIST community members on March 12, advised all undergraduate students who had already moved in to the dormitories to move out by March 23. The university opened the spring semester on March 16, two weeks later than originally scheduled, due to the outbreak. All in-person classes have been shifted to online classes and this will continue until further notice.
“The dormitory would likely become the source of a COVID-19 cluster on the campus. Given the gravity of the current situation, we can’t help but make this unprecedented measure. It is fully for the best interests for our students’ health and safety. It saddens me to say that students are required to go back to their homes,” said Provost Lee. Dormitory fees will be refunded, and transportation and storage services will be provided for students who return back home. It has not yet been decided when they can return to the campus.
There are four exceptional cases for this special measure: 1. when a student does not have legal residency in Korea, 2. if a student’s legal residence is located in a severely affected region such as Daegu, Chongdo, and Kyongsan, 3. if students in their final semester before the graduation need to take a research class that is not available online, 4. if students have a very special reason that does not allow them to stay at home. Such students are required to meet the Associate Vice President of Student Life for approval of the exceptional stay.
Meanwhile, the first day of the online semester on March 16 saw an overwhelming amount of traffic on the remote educational platform, the KAIST learning management system (KLMS), and the real-time platform, Zoom. The two systems were both overloaded. The Dean of the KAIST Academy sent an email to the community, explaining the technical glitch causing the overload. He said his office had fixed the problem, allowing resumed access to the system from inside and outside the campus. Considered the nature of classes that are difficult or impossible to provide online, the university decided to cancel the some of physical training classes such as golf, dance sports, badminton, swimming, and tennis this semester.
Social distancing is another issue the university is enhancing throughout the campus. The university announced new lunch break shifts to disperse the dining hall crowds; the first shift is from 11:30 to 12:30 and the second shift is from 12:30 to 13:30, effective from March 17. The COVID-19 response bulletin also instructed KAIST community members to sit in a row, not face to face, when eating together with colleagues, and asked them to refrain from talking while eating. In addition, a total of 29 virus and fine duster filtering machines have been installed across the campus dining facilities.
The bulletin posted on March 13 restressed the importance of wearing a face mask in compact areas such as elevators and refrain the non-essential business or personal travel. Parents who need to take care of their children due to the closure of schools and day care centers are advised to work from home.
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2020.03.16 View 7115 -
COVID-19 Update: All Classes to Go Online after Semester Opens
All classes of undergraduate and graduate courses will go online from March 16 in a protective measure for the KAIST community to slow the spread of COVID-19. No decision has yet been made for how long the online classes will last. The spring semester will start two weeks later than scheduled due to the outbreak of the COVID-19.
For online classes, professors are uploading their taped class video clips onto the KAIST Learning Management System (KLMS). These classes will be conducted in both real time and on demand. The video conferencing solution Zoom will be employed for real-time online classes, and professors and students will interact using the bulletin board function for on-demand classes.
The university is scaling up its institutional response to protect the KAIST community against the outbreak of the disease following the cancellation and postponing of major academic events including the commencement and matriculation ceremonies scheduled in February and March.
The new protective measures include all sports complexes and facilities temporarily closing from February 24. All building entrance gates are only accessible with those carrying a KAIST ID card. A total of nine fever monitors have been installed in the university headquarter building, main library, dining halls, the day care center at Daejeon campus, and at the Seoul campus.
The Emergency Response Team is posting a daily bulletin and response manual on the KAIST portal system with updates on the number of confirmed cases in Daejeon and other regions including Seoul as well as reminder notices to help contain the spread.
Provost Kwang-Hyung Lee advised KAIST community members to refrain from traveling to the gravely affected region and foreign countries in an email sent on March 11. Anyone who has a travel history in those regions should report it to the Emergency Response Team and self-quarantine for two weeks at home or in a designated dorm complex.
KAIST surveyed all community members’ travel histories last month and instructed those who had traveled to Daegu and foreign countries or had contact with a confirmed patient to go into self-isolation or work from home while conducting intensive self-monitoring. They have been asked to report their temperature to the Emergency Response Team twice a day. The response manual recommends canceling or postponing meetings and events at the campus. “If necessary, we ask that you make a conference call instead,” said the Emergency Response Team.
Meanwhile, the Academic Affairs Office decided to employ a flexible academic schedule in consideration of students’ circumstances during this extraordinary outbreak situation. “We still need to run 16 weeks of classes for the semester but we are being flexible in how the classes can be run. It will wholly depend on the professor and students’ discussions based on their situation. We won’t apply a unilateral mid-term and final exam week during this special time,” said the bulletin from the Academic Affairs Office.
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2020.03.11 View 6867 -
“A drop of water shall be returned with a rushing river.”
- Chinese KAISTians Donate Supplies to Fight COVID-19 in Daegu -
The Chinese community at KAIST donated 2.49 million won worth of personal protective equipment on March 4 to support on-site medical personnel in the city of Daegu. South Korea has been witnessing a significant surge in novel COVID-19 transmissions, and Daegu and nearby North Gyeongsang Province are the most affected regions.
As the COVID-19 situation grows more serious globally day by day, a Chinese master’s student from the KAIST Department of Civil and Environmental Engineering, Yuewen Jia, suggested a fundraising campaign on the KAIST Chinese Community’s WeChat messenger chat room, and her idea was enthusiastically supported by many peer-members. The KAIST Chinese Community is comprised of 105 undergraduates, graduates, post-doctoral fellows, researchers, and professors.
With Jia’s post-doc colleague Pei Li volunteering to manage the fundraising process, a total of 2.49 million won was collected in 12 days between January 27 and February 7.
The donors, including Qin Xu, a PhD candidate in the School of Electrical Engineering, reportedly asked for their donations to be used to support on-site medical personnel affected by the outbreak. They believed that medical supplies are the most essential in times like these. The group purchased personal protective equipment online and waited for more than 20 days until the items were finally delivered to them. The goods include 1,280 protective caps, 57 protective suits, 15 protective glasses, and two protective face shields.
Given the surging spread of the COVID-19 disease in Korea, where the confirmed cases have increased multi-fold since mid-February, the KAIST Chinese Community decided that their items should be used immediately in Korea, instead of being sent back to their home country as they had planned.
Guoyuan An, a student representative of the community studying for his master’s degree in the School of Computing, said, “Earlier, some members of the KAIST Chinese Community who had visited China were self-quarantined for two weeks in a special facility designated by KAIST as a precautionary measure. Thanks to the outstanding care we received from offices at KAIST including the COVID-19 Task Force Team, the International Office, the Student Offices, and the Clinic, those who were quarantined could return to campus safe and healthy.”
He continued, “KAIST and the Koreans as a whole spared no effort in helping China and Chinese people living in Korea fight the COVID-19 outbreak in its early days, and all of the members of the KAIST Chinese Community felt deeply grateful for all the attention and aid. This has been a definitive reason for us to change the donate recipient from China to Korea.”
“As an old Chinese saying goes, ‘A drop of water shall be returned with a rushing river.’ This proverb means that even if you receive a little help from others, you should return the favor with all you can when others are in need. We decided to make a donation ourselves in hopes that our small contribution could help on-site medical personnel work for the health and wellbeing of Koreans who are affected in that area.” he explained.
The donated items were delivered to the Division of Disaster Preparedness and Emergency Management at the Daegu Metropolitan Government Office, with help from the on-campus medical center KAIST Clinic Pappalardo Center and the KAIST International Scholar and Student Services (ISSS) Team.
Dr. Yun-Jung Lee, the executive director of the KAIST Clinic Pappalardo Center, expressed “a huge thank you to the KAIST Chinese Community for pitching in to help battle this national and global crisis.”
She added, “Their donations have been passed to those in desperate need, and their warm-hearted act of kindness will go a long way.”
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2020.03.05 View 8402 -
New Catalyst Recycles Greenhouse Gases into Fuel and Hydrogen Gas
< Professor Cafer T. Yavuz (left), PhD Candidate Youngdong Song (center), and Researcher Sreerangappa Ramesh (right) >
Scientists have taken a major step toward a circular carbon economy by developing a long-lasting, economical catalyst that recycles greenhouse gases into ingredients that can be used in fuel, hydrogen gas, and other chemicals. The results could be revolutionary in the effort to reverse global warming, according to the researchers. The study was published on February 14 in Science.
“We set out to develop an effective catalyst that can convert large amounts of the greenhouse gases carbon dioxide and methane without failure,” said Cafer T. Yavuz, paper author and associate professor of chemical and biomolecular engineering and of chemistry at KAIST.
The catalyst, made from inexpensive and abundant nickel, magnesium, and molybdenum, initiates and speeds up the rate of reaction that converts carbon dioxide and methane into hydrogen gas. It can work efficiently for more than a month.
This conversion is called ‘dry reforming’, where harmful gases, such as carbon dioxide, are processed to produce more useful chemicals that could be refined for use in fuel, plastics, or even pharmaceuticals. It is an effective process, but it previously required rare and expensive metals such as platinum and rhodium to induce a brief and inefficient chemical reaction.
Other researchers had previously proposed nickel as a more economical solution, but carbon byproducts would build up and the surface nanoparticles would bind together on the cheaper metal, fundamentally changing the composition and geometry of the catalyst and rendering it useless.
“The difficulty arises from the lack of control on scores of active sites over the bulky catalysts surfaces because any refinement procedures attempted also change the nature of the catalyst itself,” Yavuz said.
The researchers produced nickel-molybdenum nanoparticles under a reductive environment in the presence of a single crystalline magnesium oxide. As the ingredients were heated under reactive gas, the nanoparticles moved on the pristine crystal surface seeking anchoring points. The resulting activated catalyst sealed its own high-energy active sites and permanently fixed the location of the nanoparticles — meaning that the nickel-based catalyst will not have a carbon build up, nor will the surface particles bind to one another.
“It took us almost a year to understand the underlying mechanism,” said first author Youngdong Song, a graduate student in the Department of Chemical and Biomolecular Engineering at KAIST. “Once we studied all the chemical events in detail, we were shocked.”
The researchers dubbed the catalyst Nanocatalysts on Single Crystal Edges (NOSCE). The magnesium-oxide nanopowder comes from a finely structured form of magnesium oxide, where the molecules bind continuously to the edge. There are no breaks or defects in the surface, allowing for uniform and predictable reactions.
“Our study solves a number of challenges the catalyst community faces,” Yavuz said. “We believe the NOSCE mechanism will improve other inefficient catalytic reactions and provide even further savings of greenhouse gas emissions.”
This work was supported, in part, by the Saudi-Aramco-KAIST CO2 Management Center and the National Research Foundation of Korea.
Other contributors include Ercan Ozdemir, Sreerangappa Ramesh, Aldiar Adishev, and Saravanan Subramanian, all of whom are affiliated with the Graduate School of Energy, Environment, Water and Sustainability at KAIST; Aadesh Harale, Mohammed Albuali, Bandar Abdullah Fadhel, and Aqil Jamal, all of whom are with the Research and Development Center in Saudi Arabia; and Dohyun Moon and Sun Hee Choi, both of whom are with the Pohang Accelerator Laboratory in Korea. Ozdemir is also affiliated with the Institute of Nanotechnology at the Gebze Technical University in Turkey; Fadhel and Jamal are also affiliated with the Saudi-Armco-KAIST CO2 Management Center in Korea.
<Newly developed catalyst that recycles greenhouse gases into ingredients that can be used in fuel, hydrogen gas and other chemicals.>
Publication:
Song et al. (2020) Dry reforming of methane by stable Ni–Mo nanocatalysts on single-crystalline MgO. Science, Vol. 367, Issue 6479, pp. 777-781. Available online at http://dx.doi.org/10.1126/science.aav2412
Profile: Prof. Cafer T. Yavuz, MA, PhD
yavuz@kaist.ac.kr
http://yavuz.kaist.ac.kr/
Associate Professor
Oxide and Organic Nanomaterials for the Environment (ONE) Laboratory
Graduate School of Energy, Environment, Water and Sustainability (EEWS)
Korea Advanced Institute of Science and Technology (KAIST)
http://kaist.ac.kr
Daejeon, Republic of Korea
Profile: Youngdong Song ydsong88@kaist.ac.kr
Ph.D. Candidate
Department of Chemical and Biomolecular Engineering
Korea Advanced Institute of Science and Technology (KAIST)
http://kaist.ac.kr
Daejeon, Republic of Korea
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2020.02.17 View 15035 -
What Fuels a “Domino Effect” in Cancer Drug Resistance?
KAIST researchers have identified mechanisms that relay prior acquired resistance to the first-line chemotherapy to the second-line targeted therapy, fueling a “domino effect” in cancer drug resistance. Their study featured in the February 7 edition of Science Advances suggests a new strategy for improving the second-line setting of cancer treatment for patients who showed resistance to anti-cancer drugs.
Resistance to cancer drugs is often managed in the clinic by chemotherapy and targeted therapy. Unlike chemotherapy that works by repressing fast-proliferating cells, targeted therapy blocks a single oncogenic pathway to halt tumor growth. In many cases, targeted therapy is engaged as a maintenance therapy or employed in the second-line after front-line chemotherapy.
A team of researchers led by Professor Yoosik Kim from the Department of Chemical and Biomolecular Engineering and the KAIST Institute for Health Science and Technology (KIHST) has discovered an unexpected resistance signature that occurs between chemotherapy and targeted therapy. The team further identified a set of integrated mechanisms that promotes this kind of sequential therapy resistance.
“There have been multiple clinical accounts reflecting that targeted therapies tend to be least successful in patients who have exhausted all standard treatments,” said the first author of the paper Mark Borris D. Aldonza. He continued, “These accounts ignited our hypothesis that failed responses to some chemotherapies might speed up the evolution of resistance to other drugs, particularly those with specific targets.”
Aldonza and his colleagues extracted large amounts of drug-resistance information from the open-source database the Genomics of Drug Sensitivity in Cancer (GDSC), which contains thousands of drug response data entries from various human cancer cell lines. Their big data analysis revealed that cancer cell lines resistant to chemotherapies classified as anti-mitotic drugs (AMDs), toxins that inhibit overacting cell division, are also resistant to a class of targeted therapies called epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs).
In all of the cancer types analyzed, more than 84 percent of those resistant to AMDs, representatively ‘paclitaxel’, were also resistant to at least nine EGFR-TKIs. In lung, pancreatic, and breast cancers where paclitaxel is often used as a first-line, standard-of-care regimen, greater than 92 percent showed resistance to EGFR-TKIs. Professor Kim said, “It is surprising to see that such collateral resistance can occur specifically between two chemically different classes of drugs.”
To figure out how failed responses to paclitaxel leads to resistance to EGFR-TKIs, the team validated co-resistance signatures that they found in the database by generating and analyzing a subset of slow-doubling, paclitaxel-resistant cancer models called ‘persisters’.
The results demonstrated that paclitaxel-resistant cancers remodel their stress response by first becoming more stem cell-like, evolving the ability to self-renew to adapt to more stressful conditions like drug exposures. More surprisingly, when the researchers characterized the metabolic state of the cells, EGFR-TKI persisters derived from paclitaxel-resistant cancer cells showed high dependencies to energy-producing processes such as glycolysis and glutaminolysis.
“We found that, without an energy stimulus like glucose, these cells transform to becoming more senescent, a characteristic of cells that have arrested cell division. However, this senescence is controlled by stem cell factors, which the paclitaxel-resistant cancers use to escape from this arrested state given a favorable condition to re-grow,” said Aldonza.
Professor Kim explained, “Before this research, there was no reason to expect that acquiring the cancer stem cell phenotype that dramatically leads to a cascade of changes in cellular states affecting metabolism and cell death is linked with drug-specific sequential resistance between two classes of therapies.”
He added, “The expansion of our work to other working models of drug resistance in a much more clinically-relevant setting, perhaps in clinical trials, will take on increasing importance, as sequential treatment strategies will continue to be adapted to various forms of anti-cancer therapy regimens.”
This study was supported by the Basic Science Research Program of the National Research Foundation of Korea (NRF-2016R1C1B2009886), and the KAIST Future Systems Healthcare Project (KAISTHEALTHCARE42) funded by the Korean Ministry of Science and ICT (MSIT). Undergraduate student Aldonza participated in this research project and presented the findings as the lead author as part of the Undergraduate Research Participation (URP) Program at KAIST.
< Figure 1. Schematic overview of the study. >
< Figure 2. Big data analysis revealing co-resistance signatures between classes of anti-cancer drugs. >
Publication:
Aldonza et al. (2020) Prior acquired resistance to paclitaxel relays diverse EGFR-targeted therapy persistence mechanisms. Science Advances, Vol. 6, No. 6, eaav7416. Available online at http://dx.doi.org/10.1126/sciadv.aav7416
Profile: Prof. Yoosik Kim, MA, PhD
ysyoosik@kaist.ac.kr
https://qcbio.kaist.ac.kr/
Assistant Professor
Bio Network Analysis Laboratory
Department of Chemical and Biomolecular Engineering
Korea Advanced Institute of Science and Technology (KAIST)
http://kaist.ac.kr
Daejeon, Republic of Korea
Profile: Mark Borris D. Aldonza
borris@kaist.ac.kr
Undergraduate Student
Department of Biological Sciences
Korea Advanced Institute of Science and Technology (KAIST)
http://kaist.ac.kr
Daejeon, Republic of Korea
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2020.02.10 View 11671 -
New KAA President Chilhee Chung Calls Alumni Engagement a Top Priority
The KAIST Alumni Association (KAA) inaugurated Advisor Chilhee Chung of Samsung Electronics as its new president. President Chung was preceded by Ki-Chul Cha, the CEO of Inbody Co. Ltd. His term as the 25th president starts from February 2020 and ends in January 2022.
President Chung received his master’s degree from KAIST's Department of Physics in 1979 and joined Samsung Electronics the same year. He also holds a doctorate in physics from Michigan State University in the United States.
President Chung devoted himself to helping Samsung Electronics and Korea's system semiconductor and memory device technologies achieve global dominance for more than 40 years. He led future technology development at Samsung Electronics in the fields of quantum dot and neural processing from various leadership positions, including the head of the Semiconductor R&D Center, and the president of Samsung Advanced Institute of Technology (SAIT).
President Chung is currently an advisor to SAIT, a member of the Presidential Advisory Council on Science and Technology (PACST), and the chairman of the 2045 National Future Strategy Committee and the Nano Technology Research Association (NTRA).
President Chung said, “KAIST, throughout its history of half a century, has been working tirelessly to become the world’s best, beyond being the best in Korea. We, the alumni of KAIST, have the commensurate duty as well as the privilege of being proud members of KAIST, as the university's global stature grows.”
“Recently, 46 alumni made 535 million won in donations, and established a scholarship to encourage entrepreneurial spirit in members of the KAIST community. This fund was dedicated to supporting 30 alumni entrepreneurs and students participating in the International Consumer Electronics Show (CES) 2020 that was held in Las Vegas last month. Moreover, another alumnus of ours Byeong-Gyu Chang, the CSO of the KRAFTON Inc., donated 10 billion won to KAIST in hopes of opening up more opportunities that may lead KAIST students to success. Mr. Chang’s donation is by far the largest that has been made by KAIST alumni. I feel grateful to see more alumni getting involved in shaping the future of KAIST these days, and my top priority as the new president of the KAA will be to stimulate the alumni association and engagement in the spirit of ‘Team KAIST’,” he added.
More than 900 alumni, including President Sung-Chul Shin who is also an alumnus of KAIST, gathered in Seoul on January 18 to celebrate the New Year and the newly-elected leadership of the KAA.
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2020.02.03 View 6266 -
Distinguished Alumni Awardees 2019
The KAIST Alumni Association (KAA) announced four recipients of the Distinguished Alumni Awards for the year 2019. The awards ceremony took place during the New Year Alumni Reception on January 18, 2020 in Seoul.
The Distinguished Alumni Awards recognize graduates who have achieved outstanding accomplishments in their professional and personal lives, and who have been an inspiration to fellow alumni and students in Korea and around the globe. The four distinguished alumni of the year 2019 are listed below.
Myung Joon Kim (School of Computing, M.S., Class of ’78), the President of the Electronics and Telecommunications Research Institute (ETRI), is a renowned expert in software engineering who has served as the president of the Administration Division and ICT Creative Research Laboratory of ETRI. His research and leadership have contributed to fortifying the nation’s IT and electronic industry competitiveness.
Dong Ryeol Shin (School of Electrical Engineering, M.S., Class of ’80), the President of Sungkyunkwan University, is a well-versed expert experienced in both academia and industry. He suggested many creative interdisciplinary educational policies and innovative education programs to lead the way in the Fourth Industrial Revolution, and fostered talents who will go on to be the foundation of national development.
Dong-Myun Lee (School of Electrical Engineering, M.S., Class of ’85, Ph.D., Class of ‘87), the CTO and the head of the Institute of Convergence Technology in KT Corporation, is a creative and practical research innovator. He raised the nation’s competitiveness by leading the development of the high-speed communication network industry and the global expansion of next-generation technology business.
Chang Han Kim (School of Computing, B.S., Class of ’92, M.S., Class of ’97, Ph.D., Class of ’98), the CEO of PUBG Corporation, has contributed greatly to the development of the IT contents industry. He developed PlayerUnknown’s Battlegrounds, a game that has become a global sensation.
Since the establishment of the award in 1992, a total of 103 alumni at home and abroad have been honored as recipients, and brought distinction to the university.
These recipients are playing major roles in society, and some of the notable awardees include: KAIST President Sung-Chul Shin (2010), Samsung Electronics Vice Chairman Ki-Nam Kim (2012), Nexon Chairman Jung-Ju Kim (2007), and the former Science and Technology Advisor to the President Kong-Joo Lee (2005).
The President of KAA and the CEO of Inbody Co Ltd., Ki-Chul Cha, said, “The Distinguished Alumni Awards are honor given to the alumni who contributed to the development of the nation and society, and raised the name of their alma mater.” He added, “We can tell the proud position of KAIST in the global arena just by looking at the accomplishments of the previous awardees.”
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2020.01.20 View 8386 -
KAIST and Google Jointly Develop AI Curricula
KAIST selected the two professors who will develop AI curriculum under the auspices of the KAIST-Google Partnership for AI Education and Research. The Graduate School of AI announced the two authors among the 20 applicants who will develop the curriculum next year. They will be provided 7,500 USD per subject.
Professor Changho Suh from the School of Electrical Engineering and Professor Yong-Jin Yoon from the Department of Mechanical Engineering will use Google technology such as TensorFlow, Google Cloud, and Android to create the curriculum.
Professor Suh’s “TensorFlow for Information Theory and Convex Optimization “will be used for curriculum in the graduate courses and Professor Yoon’s “AI Convergence Project Based Learning (PBL)” will be used for online courses. Professor Yoon’s course will explore and define problems by utilizing AI and experiencing the process of developing products that use AI through design thinking, which involves product design, production, and verification. Professor Suh’s course will discus“information theory and convergence,” which uses basic sciences and engineering as well as AI, machine learning, and deep learning.
2019.12.04 View 11277 -
‘Carrier-Resolved Photo-Hall’ to Push Semiconductor Advances
(Professor Shin and Dr. Gunawan (left))
An IBM-KAIST research team described a breakthrough in a 140-year-old mystery in physics. The research reported in Nature last month unlocks the physical characteristics of semiconductors in much greater detail and aids in the development of new and improved semiconductor materials.
Research team under Professor Byungha Shin at the Department of Material Sciences and Engineering and Dr. Oki Gunawan at IBM discovered a new formula and technique that enables the simultaneous extraction of both majority and minority carrier information such as their density and mobility, as well as gain additional insights about carrier lifetimes, diffusion lengths, and the recombination process. This new discovery and technology will help push semiconductor advances in both existing and emerging technologies.
Semiconductors are the basic building blocks of today’s digital electronics age, providing us with a multitude of devices that benefit our modern life. To truly appreciate the physics of semiconductors, it is very important to understand the fundamental properties of the charge carriers inside the materials, whether those particles are positive or negative, their speed under an applied electric field, and how densely they are packed into the material.
Physicist Edwin Hall found a way to determine those properties in 1879, when he discovered that a magnetic field will deflect the movement of electronic charges inside a conductor and that the amount of deflection can be measured as a voltage perpendicular to the flow of the charge. Decades after Hall’s discovery, researchers also recognized that they can measure the Hall effect with light via “photo-Hall experiments”. During such experiments, the light generates multiple carriers or electron–hole pairs in the semiconductors.
Unfortunately, the basic Hall effect only provided insights into the dominant charge carrier (or majority carrier). Researchers were unable to extract the properties of both carriers (the majority and minority carriers) simultaneously. The property information of both carriers is crucial for many applications that involve light such as solar cells and other optoelectronic devices.
In the photo-Hall experiment by the KAIST-IBM team, both carriers contribute to changes in conductivity and the Hall coefficient. The key insight comes from measuring the conductivity and Hall coefficient as a function of light intensity. Hidden in the trajectory of the conductivity, the Hall coefficient curve reveals crucial new information: the difference in the mobility of both carriers. As discussed in the paper, this relationship can be expressed elegantly as: Δµ = d (σ²H)/dσ
The research team solved for both majority and minority carrier mobility and density as a function of light intensity, naming the new technique Carrier-Resolved Photo Hall (CRPH) measurement. With known light illumination intensity, the carrier lifetime can be established in a similar way.
Beyond advances in theoretical understanding, advances in experimental techniques were also critical for enabling this breakthrough. The technique requires a clean Hall signal measurement, which can be challenging for materials where the Hall signal is weak due to low mobility or when extra unwanted signals are present, such as under strong light illumination.
The newly developed photo-Hall technique allows the extraction of an astonishing amount of information from semiconductors. In contrast to only three parameters obtained in the classic Hall measurements, this new technique yields up to seven parameters at every tested level of light intensity. These include the mobility of both the electron and hole; their carrier density under light; the recombination lifetime; and the diffusion lengths for electrons, holes, and ambipolar types. All of these can be repeated N times (i.e. the number of light intensity settings used in the experiment).
Professor Shin said, “This novel technology sheds new light on understanding the physical characteristics of semiconductor materials in great detail.” Dr. Gunawan added, “This will will help accelerate the development of next-generation semiconductor technology such as better solar cells, better optoelectronics devices, and new materials and devices for artificial intelligence technology.”
Profile:
Professor Byungha Shin
Department of Materials Science and Engineering
KAIST
byungha@kaist.ac.kr
http://energymatlab.kaist.ac.kr/
2019.11.18 View 12555 -
Highly Uniform and Low Hysteresis Pressure Sensor to Increase Practical Applicability
< Professor Steve Park (left) and the First Author Mr. Jinwon Oh (right) >
Researchers have designed a flexible pressure sensor that is expected to have a much wider applicability. A KAIST research team fabricated a piezoresistive pressure sensor of high uniformity with low hysteresis by chemically grafting a conductive polymer onto a porous elastomer template.
The team discovered that the uniformity of pore size and shape is directly related to the uniformity of the sensor. The team noted that by increasing pore size and shape variability, the variability of the sensor characteristics also increases.
Researchers led by Professor Steve Park from the Department of Materials Science and Engineering confirmed that compared to other sensors composed of randomly sized and shaped pores, which had a coefficient of variation in relative resistance change of 69.65%, their newly developed sensor exhibited much higher uniformity with a coefficient of variation of 2.43%. This study was reported in Small as the cover article on August 16.
Flexible pressure sensors have been actively researched and widely applied in electronic equipment such as touch screens, robots, wearable healthcare devices, electronic skin, and human-machine interfaces. In particular, piezoresistive pressure sensors based on elastomer‐conductive material composites hold significant potential due to their many advantages including a simple and low-cost fabrication process.
Various research results have been reported for ways to improve the performance of piezoresistive pressure sensors, most of which have been focused on increasing the sensitivity. Despite its significance, maximizing the sensitivity of composite-based piezoresistive pressure sensors is not necessary for many applications. On the other hand, sensor-to-sensor uniformity and hysteresis are two properties that are of critical importance to realize any application.
The importance of sensor-to-sensor uniformity is obvious. If the sensors manufactured under the same conditions have different properties, measurement reliability is compromised, and therefore the sensor cannot be used in a practical setting.
In addition, low hysteresis is also essential for improved measurement reliability. Hysteresis is a phenomenon in which the electrical readings differ depending on how fast or slow the sensor is being pressed, whether pressure is being released or applied, and how long and to what degree the sensor has been pressed. When a sensor has high hysteresis, the electrical readings will differ even under the same pressure, making the measurements unreliable.
Researchers said they observed a negligible hysteresis degree which was only 2%. This was attributed to the strong chemical bonding between the conductive polymer and the elastomer template, which prevents their relative sliding and displacement, and the porosity of the elastomer that enhances elastic behavior.
“This technology brings forth insight into how to address the two critical issues in pressure sensors: uniformity and hysteresis. We expect our technology to play an important role in increasing practical applications and the commercialization of pressure sensors in the near future,” said Professor Park.
This work was conducted as part of the KAIST‐funded Global Singularity Research Program for 2019, and also supported by the KUSTAR‐KAIST Institute.
Figure 1. Image of a porous elastomer template with uniform pore size and shape (left), Graph showing high uniformity in the sensors’ performance (right).
Figure 2. Hysteresis loops of the sensor at different pressure levels (left), and after a different number of cycles (right).
Figure 3. The cover page of Small Journal, Volume 15, Issue 33.
Publication:
Jinwon Oh, Jin‐Oh Kim, Yunjoo Kim, Han Byul Choi, Jun Chang Yang, Serin Lee, Mikhail Pyatykh, Jung Kim, Joo Yong Sim, and Steve Park. 2019. Highly Uniform and Low Hysteresis Piezoresistive Pressure Sensors Based on Chemical Grafting of Polypyrrole on Elastomer Template with Uniform Pore Size. Small. Wiley-VCH Verlag GmbH & Co. KgaA, Weinheim, Germany, Volume No. 15, Issue No. 33, Full Paper No. 201901744, 8 pages. https://doi.org/10.1002/smll.201901744
Profile: Prof. Steve Park, MS, PhD
stevepark@kaist.ac.kr
http://steveparklab.kaist.ac.kr/
Assistant Professor
Organic and Nano Electronics Laboratory
Department of Materials Science and Engineering
Korea Advanced Institute of Science and Technology (KAIST)
http://kaist.ac.kr
Daejeon 34141, Korea
Profile: Mr. Jinwon Oh, MS
jwoh1701@gmail.com
http://steveparklab.kaist.ac.kr/
Researcher
Organic and Nano Electronics Laboratory
Department of Materials Science and Engineering
Korea Advanced Institute of Science and Technology (KAIST)
http://kaist.ac.kr Daejeon 34141, Korea
Profile: Prof. Jung Kim, MS, PhD
jungkim@kaist.ac.kr
http://medev.kaist.ac.kr/
Professor
Biorobotics Laboratory
Department of Mechanical Engineering
Korea Advanced Institute of Science and Technology (KAIST)
http://kaist.ac.kr Daejeon 34141, Korea
Profile: Joo Yong Sim, PhD
jsim@etri.re.kr
Researcher
Bio-Medical IT Convergence Research Department
Electronics and Telecommunications Research Institute (ETRI)
https://www.etri.re.krDaejeon 34129, Korea
(END)
2019.08.19 View 25694 -
Research Day Highlights Most Outstanding Research Achievements
Professor Byung Jin Cho from the School of Electrical Engineering was selected as the Grand Research Prize Winner in recognition of his innovative research achievement in the fields of nano electric and flexible energy devices during the 2019 KAIST Research Day ceremony held on April 23 at the Chung Kunmo Conference Hall.
The ten most outstanding research achievements from the past year were also awarded in the three areas of Research, Innovation, Convergence Researches.
Professor Cho is an internationally recognized researcher in the field of future nano and energy device technology. Professor Cho’s team has continued to research on advanced CMOS (complementary metal-oxide semiconductors). CMOS has become his key research topic over the past three decades.
In 2014, he developed a glass fabric-based thermoelectric generator, which is extremely light and flexible and produces electricity from the heat of the human body. It is so flexible that the allowable bending radius of the generator is as low as 20 mm. There are no changes in performance even if the generator bends upward and downward for up to 120 cycles. His wearable thermoelectric generator was selected as one of the top ten most promising digital technologies by the Netexplo Forum in 2015.
He now is working on high-performance and ultra-flexible CMOS IC for biomedical applications, expanding his scope to thermal haptic technology in VR using graphene-CMOS hybrid integrated circuits; to self-powered wireless sensor nodes and self-powered ECG system using wearable thermoelectric generators .
In his special lecture at the ceremony, Professor Cho stressed the importance of collaboration in making scientific research and presented how he moved to future devices after focusing on scaling the devices.
“When I started the research on semiconductors, I focused on how to scale the device down as much as possible. For decades, we have conducted a number of procedures to produce tiny but efficient materials. Now we have shifted to develop flexible thermoelements and wearable devices,” said Professor Cho.
“We all thought the scaling down is the only way to create value-added technological breakthroughs. Now, the devices have been scaled down to 7nm and will go down to 5 nm soon. Over the past few years, I think we have gone through all the possible technological breakthroughs for reducing the size to 5nm. The semiconductor devices are made of more 1 billion transistors and go through 1,000 technological processes. So, there won’t be any possible way for a single genius to make a huge breakthrough. Without collaboration with others, it is nearly impossible to make any new technological breakthroughs.”
Professor Cho has published more than 240 papers in renowned academic journals and presented more than 300 papers at academic conferences. He has also registered approximately 50 patents in the field of semiconductor device technology.
The top ten research highlights of 2018 as follows:
- Rydberg-Atom Quantum Simulator Development by Professor Jaewook Ahn and Heung-Sun Sim from the Department of Physics
- From C-H to C-C Bonds at Room Temperature by Professor Mu-Hyun Baik from the Department of Chemistry
- The Role of Rodlike Counterions on the Interactions of DNAs by Professor Yong Woon Kim of the Graduate School of Nanoscience and Technology
- The Medal Preoptic Area Induces Hunting-Like Behaviors to Target Objects and Prey by Professor Daesoo Kim from the Department of Biological Sciences
- Identification of the Origin of Brain Tumors and New Therapeutic Strategy by Professor Jeong Ho Lee from the Graduate School of Medical Science and Engineering
- The Linear Frequency Conversion of Light at a Spatiotemporal Boundary by Professor Bumki Min from the Department of Mechanical Engineering
- An Industrial Grade Flexible Transparent Force Touch Sensor by Professor Jun-Bo Yoon from the School of Electrical Engineering
- The Detection and Clustering of Mixed-Type Defect Patterns in Wafer Bin Maps by Professor Heeyoung Kim from the Department of Industrial and Systems Engineering
- The Development of a Reconfigurable Spin-Based Logic Device by Professor Byong-Guk Park from the Department of Materials Science and Engineering
- The Development of a Miniaturized X-Ray Tube Based on Carbon Nanotube and Electronic Brachytherapy Device by Professor Sung Oh Cho from the Department of Nuclear and Quantum Engineering
Professor YongKeun Park from the Department of Physics and Professor In-Chel Park from the School of Electrical Engineering received the Research Award. For the Innovation Award, Professor Munchurl Kim from the School of Electrical Engineering was the recipient and the Convergence Research Awards was conferred to Professor Sung-Yool Choi from the School of Electrical Engineering, Professor Sung Gap Im from the Department of Chemical and Biomolecular Engineering, and Professor SangHee Park from the Department of Materials Science and Engineering during the ceremony.
For more on KAIST’s Top Research Achievements and Highlight of 2018, please refer to the attached below. click.
2019.04.25 View 13709 -
KAIST 2019 Commencement at a Glance
(KAIST 2019 Commencement Ceremony)
This year, KAIST awarded a total of 2,705 degrees: 654 PhD degrees, 1,255 master’s degrees, and 796 bachelor’s degrees. Including this year’s numbers, KAIST has conferred a total of 63,830 degrees since its foundation in 1971.
Parents, family, and friends came to campus to congratulate the graduates with big smiles and hugs. Faculty and staff members also attended the ceremony to celebrate their graduation. This year, distinguished guests including National Assembly Member Kyung-Jin Kim and Vice Minister for Science, Technology and Innovation Dae-sik came to celebrate the day with the KAIST community.
During the commencement, KAIST also announced the recipients of its undergraduate academic awards. The Minister of Science and ICT Award was won by Do-Yoon Kim from the Department of Aerospace Engineering, the KAIST Board of Trustee Chairperson Award went to Se-rin Lee from the Department of Materials Science and Engineering, the KAIST Presidential Award was won by Hee-Ju Kim from the Department of Physics, the KAIST Alumni Association President Award went to Hyeon-Seong Park from the School of Electrical Engineering, and finally the KAIST Development Foundation Chairperson Award was won by Gyeong-Hoon Lee from the Department of Mathematical Sciences.
This year’s valedictorian Eun-Seok Jeong from the School of Computing said, “I believe that we are able to stand here today because we challenged ourselves to confront our shortcomings and our uncertainty. If we continue to develop, we will become a better person than we were yesterday.”
(KAIST President Sung-Chul Shin and Woo-Seok Jeong, '19 PhD in Aerospace Engineering)
As a KAIST alumnus and fellow scientist, President Sung-Chul Shin offered his congratulations and emphasized that graduates should continue to pursue the C³ spirit. “In this age of great transformation, embrace challenges and exercise creativity as you have learnt through your education and research at KAIST. And keep in mind the importance of caring for others. Please remember that challenge and creativity will have more meaning if rendered with a caring spirit,” he said.
2019.02.15 View 8583