LLO
-
Former Minister of Science and Technology Woo Sik Kim Elected as New Chairman of Board of Trustees
Dr. Woo Sik Kim, former Minister of Science and Technology and Deputy Prime Minister, was elected as the new chairman of the KAIST Board of Trustees on March 26. Dr. Kim will succeed Chairman Jang-Mu Lee, whose three-year term expired last month.
Dr. Kim is a chemical engineering professor who spent most of his academic career at Yonsei University from 1968. In 2000, he held the office of president of Yonsei University for four years before moving to the Presidential Office of President Roh Moo-Hyun as his chief of staff in 2004. After serving in the Blue House for two years, he served as the Minister of Science and Technology from 2006 to 2008.
An emeritus fellow of the National Academy of Engineering of Korea (NAEK), Chairman Kim also taught at KAIST as an invited distinguished professor from 2008 to 2010. He is currently the chairman of the Creativity Engineering Institute (CEI).
(END)
2020.04.06 View 13666 -
COVID-19 Update: Reaching Out to Help Local Schools’ Online Classes
After the Ministry of Education decided that all schools would conduct online classes from April 9, schools began to ramp up online education tools and systems. On March 30, the Ministry announced a three-phased opening for the schools, putting online classes for third-year middle and high school students first. The online classes will expand to first and second-year middle and high schoolers and the upper grades of elementary schools on April 16, followed by first to third graders of elementary schools on April 20.
Although some schools have already introduced online teaching and learning into the curriculum, most schools are still unprepared, raising concerns over possible educational disparities caused by insufficient infrastructures and a lack of training for teachers.
To counter these issues, KAIST rolled up its sleeves to help teachers from 38 local middle and high schools in the Yuseong District of Daejeon better prepare for their interactive online classes by providing a special training course from April 7 through 29. Following the course, approximately 40 undergraduate and graduate students will be assigned to schools to help them set up and better utilize the online educational program.
On April 3, Professor Youngsun Kwon, the Dean of KAIST Academy and the Director of the Center for Excellence in Learning and Teaching, gave a two-hour online interactive tutorial session on the utilization of the real-time video conferencing platform ‘Zoom’ for online classes. He shared best practices for checking attendance, running classes, and giving and marking quizzes and assignments. A total of 102 local middle and high school teachers attended this session.
“We feel very fortunate to reach out to teachers who are so passionate about learning online education methodology. We were pleasantly surprised to see this many educators show up for the tutorial session,” said Dean Kwon. He also appreciated KAIST students’ strong interests and support in the community outreach project in response to COVID-19 during these challenging times when social distancing is so critical.
He said more than 150 student volunteers signed up for this project 10 hours after his office posted the opening for volunteers on the KAIST intranet. “We will help front-line school teachers, strictly following the government’s guidelines for social distancing,” he added.
The students’ online class support group will provide additional help to schools that are inexperienced users of Zoom. The students will be those who are very familiar with online lectures using Zoom, and are fully acquainted with how to operate them. One or two of the students will be assigned to each school that requests support, and will directly help solve complications that stem from preparing and running the classes through online measures for safety reasons. The expenses for the support group’s activities will be fully covered by KAIST, and the period of support may be extended upon request.
KAIST has been offering approximately 1,200 courses remotely since the spring semester opened on March 16 and will do so until the COVID-19 situation stabilizes. Along with the provision of pre-recorded one-way lecture contents, real-time two-way lessons are being delivered through various video conferencing platforms including Zoom, YouTube Live, and Microsoft Teams. There were both minor and major technical issues at the beginning of the semester, caused by the instability of servers and system overloads as well as from users being inexperienced with the tools and systems. However, the class procedures have gradually stabilized and are now running better.
KAIST President Sung-Chul Shin said, “As the COVID-19 situation lingers, this is a more difficult time than ever, where all educational establishments and educators must quickly learn and apply new methods of education, often in insufficient preparation conditions.” He added, “KAIST will provide support for secondary schools in the region to quickly resolve the inconveniences caused by new users of online classes so that they may provide high-quality education.”
(END)
2020.04.06 View 8542 -
Highly Efficient and Stable Double Layer Solar Cell Developed
Solar cells convert light into energy, but they can be inefficient and vulnerable to the environment, degrading with, ironically, too much light or other factors, including moisture and low temperature. An international research team has developed a new type of solar cell that can both withstand environmental hazards and is 26.7% efficient in power conversion.
They published their results on March 26 in Science.
The researchers, led by Byungha Shin, a professor from the Department of Materials Science and Engineering at KAIST, focused on developing a new class of light-absorbing material, called a wide bandgap perovskite. The material has a highly effective crystal structure that can process the power needs, but it can become problematic when exposed to environmental hazards, such as moisture. Researchers have made some progress increasing the efficiency of solar cells based on perovskite, but the material has greater potential than what was previously achieved.
To achieve better performance, Shin and his team built a double layer solar cell, called tandem, in which two or more light absorbers are stacked together to better utilize solar energy. To use perovskite in these tandem devices, the scientists modified the material’s optical property, which allows it to absorb a wider range of solar energy. Without the adjustment, the material is not as useful in achieving high performing tandem solar cells. The modification of the optical property of perovskite, however, comes with a penalty — the material becomes hugely vulnerable to the environment, in particular, to light.
To counteract the wide bandgap perovskite’s delicate nature, the researchers engineered combinations of molecules composing a two-dimensional layer in the perovskite, stabilizing the solar cells.
“We developed a high-quality wide bandgap perovskite material and, in combination with silicon solar cells, achieved world-class perovskite-silicon tandem cells,” Shin said.
The development was only possible due to the engineering method, in which the mixing ratio of the molecules building the two-dimensional layer are carefully controlled. In this case, the perovskite material not only improved efficiency of the resulting solar cell but also gained durability, retaining 80% of its initial power conversion capability even after 1,000 hours of continuous illumination. This is the first time such a high efficiency has been achieved with a wide bandgap perovskite single layer alone, according to Shin.
“Such high-efficiency wide bandgap perovskite is an essential technology for achieving ultra-high efficiency of perovskite-silicon tandem (double layer) solar cells,” Shin said. “The results also show the importance of bandgap matching of upper and lower cells in these tandem solar cells.”
The researchers, having stabilized the wide bandgap perovskite material, are now focused on developing even more efficient tandem solar cells that are expected to have more than 30% of power conversion efficiency, something that no one has achieved yet,
“Our ultimate goal is to develop ultra-high-efficiency tandem solar cells that contribute to the increase of shared solar energy among all energy sources,” Shin said. “We want to contribute to making the planet healthier.”
This work was supported by the National Research Foundation of Korea, the Korea Institute of Energy Technology Evaluation and Planning, the Ministry of Trade Industry and Energy of Korea, and the U.S. Department of Energy.
Other contributors include Daehan Kim, Jekyung Kim, Passarut Boonmongkolras, Seong Ryul Pae and Minkyu Kim, all of whom affiliated with the Department of Materials Science and Engineering at KAIST. Other authors include Byron W. Larson, Sean P. Dunfield, Chuanxiao Xiao, Jinhui Tong, Fei Zhang, Joseph J. Berry, Kai Zhu and Dong Hoe Kim, all of who are affiliated with the National Renewable Energy Laboratory in Colorado. Dunfield is also affiliated with the Materials Science and Engineering Program at the University of Colorado; Berry is also affiliated with the Department of Physics and the Renewable and Sustainable Energy Institute at the University of Colorado Boulder; and Kim is also affiliated with the Department of Nanotechnology and Advanced Materials Engineering at Sejong University. Hee Joon Jung and Vinayak Dravid of the Department of Materials Science and Engineering at Northwestern University; Ik Jae Park, Su Geun Ji and Jin Young Kim of the Department of Materials Science and Engineering at Seoul National University; and Seok Beom Kang of the Department of Nanotechnology and Advanced Materials Engineering of Sejong University also contributed.
Image credit: Professor Byungha Shin, KAIST
Image usage restrictions: News organizations may use or redistribute this image, with proper attribution, as part of news coverage of this paper only.
Publication: Kim et al. (2020) “Efficient, stable silicon tandem cells enabled by anion-engineered wide band gap perovskites”. Science. Available online at https://doi.org/10.1126/science.aba3433
Profile:
Byungha Shin
Professor
byungha@kaist.ac.kr
http://energymatlab.kaist.ac.kr/
Department of Materials Science and Engineering
KAIST
Profile:
Daehan Kim
Ph.D. Candidate
zxzx4592@kaist.ac.kr
http://energymatlab.kaist.ac.kr/
Department of Materials Science and Engineering
KAIST
(END)
2020.03.27 View 22173 -
Recyclable Nano-Fiber Filtered Face Masks a Boon for Supply Fiasco
Wearing a face mask is a common sight in Korea during the COVID-19 outbreak. Due to the overwhelming demand, last week the government started to ration two masks per person per week, as a drastic measure to address the supply fiasco.
The face masks most commonly used are disposable ones, originally made for filtering out up to 94 or 95 percent of fine dust, referred to as N94 or N95 masks.
A KAIST research team announced that they have developed a nano-filter that maintains excellent filtering efficiency even after hand washing through the development of proprietary technology that aligns nanofibers with a diameter of 100~500 nm in orthogonal or unidirectional directions. This reusable nano-filtered face mask could help to relieve the challenges arising from the supply shortage of face masks.
Professor Il-Doo Kim’s nano-fiber filtered mask will maintain its sturdy frame and filtering function even after being washed more than 20 times. Professor Kim, who has continued to study the filtering of fine dust using nano-filters, is now awaiting final approval from the Ministry of Food and Drug Safety to bring his product into the market.
Professor Kim used an insulation block electrospinning process to manufacture orthogonal nanofibers by controlling the alignment of nanofibers. This structure can minimize delivering of the pressure toward the air filter and maximize the filtration efficiency, which is different from existing disposable masks without nano-fibers.
Existing masks also fail to maintain their air filtering function because their electrostatic function disappears when exposed to water. Thus, their filtering efficiency is reduced significantly, making it almost impossible to reuse them. However, this nano-fiber design was proven to be water resistant with more than 94% filtering efficiency in 20 repeated bactericidal tests with ethanol. The nano-fiber mask also showed no deformation in its nano-membrane structure despite the 20 hand washes. In particular, it was confirmed that there were no deformations in the membrane, even after soaking in ethanol more than three hours.
Professor Kim said, “We believe that this mask can be reusable for about a month even after washing in ethanol. The inner filter can also be replaced.” He added, “We found that the mask filters out up to 80 percent of 600-nanometer particles even after undergoing a bending test more than 4,000 times.”
Professor Kim established his startup company, the “Kim Il-Doo Research Institute,” last February. It can currently produce 1,500 nano-fiber filters per day.
2020.03.17 View 23587 -
‘OSK Rising Stars 30’ Recognizes Four KAISTians
Four KAISTians were selected as star researchers to brighten the future of optics in commemoration of the 30th anniversary of the Optical Society of Korea (OSK). As ‘OSK Rising Stars 30’, the OSK named 27 domestic researchers under the age of 40 who have made significant contributions and will continue contributing to the development of Korea’s optics academia and industry.
Professor YongKeun Park from the Department of Physics was selected in recognition of his contributions to the field of biomedical optics. Professor Park focuses on developing novel optical methods for understanding, diagnosing, and treating human diseases, based on light scattering, light manipulation, and interferometry. As a member of numerous international optics societies including the OSA and the SPIE and a co-founder of two start-up companies, Professor Park continues to broaden his boundaries as a leading opticist and entrepreneur.
Professor Jonghwa Shin from the Department of Materials Science and Engineering was recognized for blazing a trail in the field of broadband metamaterials. Professor Shin’s research on the broadband enhancement of the electric permittivity and refractive index of metamaterials has great potential in both academia and industry.
Professor Hongki Yoo from the Department of Mechanical Engineering is expected to create a significant ripple effect in the diagnosis of cardiovascular disorders through the development of new optical imaging techniques and applications.
Finally, Dr. Sejeong Kim, a KAIST graduate and a Chancellor’s postdoctoral research fellow at the University of Technology Sydney (UTS), was acknowledged for her optical device research utilizing two-dimensional materials. Dr. Kim’s research at UTS now focuses on the introduction of micro/nano cavities for new materials.
(END)
2020.03.16 View 12265 -
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.
(END)
2020.03.16 View 9064 -
3D Hierarchically Porous Nanostructured Catalyst Helps Efficiently Reduce CO2
- This new catalyst will bring CO2 one step closer to serving as a sustainable energy source. -
KAIST researchers developed a three-dimensional (3D) hierarchically porous nanostructured catalyst with carbon dioxide (CO2) to carbon monoxide (CO) conversion rate up to 3.96 times higher than that of conventional nanoporous gold catalysts. This new catalyst helps overcome the existing limitations of the mass transport that has been a major cause of decreases in the CO2 conversion rate, holding a strong promise for the large-scale and cost-effective electrochemical conversion of CO2 into useful chemicals.
As CO2 emissions increase and fossil fuels deplete globally, reducing and converting CO2 to clean energy electrochemically has attracted a great deal of attention as a promising technology. Especially due to the fact that the CO2 reduction reaction occurs competitively with hydrogen evolution reactions (HER) at similar redox potentials, the development of an efficient electrocatalyst for selective and robust CO2 reduction reactions has remained a key technological issue.
Gold (Au) is one of the most commonly used catalysts in CO2 reduction reactions, but the high cost and scarcity of Au pose obstacles for mass commercial applications. The development of nanostructures has been extensively studied as a potential approach to improving the selectivity for target products and maximizing the number of active stable sites, thus enhancing the energy efficiency.
However, the nanopores of the previously reported complex nanostructures were easily blocked by gaseous CO bubbles during aqueous reactions. The CO bubbles hindered mass transport of the reactants through the electrolyte, resulting in low CO2 conversion rates.
In the study published in the Proceedings of the National Academy of Sciences of the USA (PNAS) on March 4, a research group at KAIST led by Professor Seokwoo Jeon and Professor Jihun Oh from the Department of Materials Science and Engineering designed a 3D hierarchically porous Au nanostructure with two different sizes of macropores and nanopores. The team used proximity-field nanopatterning (PnP) and electroplating techniques that are effective for fabricating the 3D well-ordered nanostructures.
The proposed nanostructure, comprised of interconnected macroporous channels 200 to 300 nanometers (nm) wide and 10 nm nanopores, induces efficient mass transport through the interconnected macroporous channels as well as high selectivity by producing highly active stable sites from numerous nanopores.
As a result, its electrodes show a high CO selectivity of 85.8% at a low overpotential of 0.264 V and efficient mass activity that is up to 3.96 times higher than that of de-alloyed nanoporous Au electrodes.
“These results are expected to solve the problem of mass transfer in the field of similar electrochemical reactions and can be applied to a wide range of green energy applications for the efficient utilization of electrocatalysts,” said the researchers.
This work was supported by the National Research Foundation (NRF) of Korea.
Image credit: Professor Seokwoo Jeon and Professor Jihun Oh, KAIST
Image usage restrictions: News organizations may use or redistribute this image, with proper attribution, as part of news coverage of this paper only.
Publication:
Hyun et al. (2020) Hierarchically porous Au nanostructures with interconnected channels for efficient mass transport in electrocatalytic CO2 reduction. Proceedings of the National Academy of Sciences of the USA (PNAS). Available online at https://doi.org/10.1073/pnas.1918837117
Profile:
Seokwoo Jeon, PhD
Professor
jeon39@kaist.ac.kr
http://fdml.kaist.ac.kr
Department of Materials Science and Engineering (MSE)
https://www.kaist.ac.kr
Korea Advanced Institute of Science and Technology (KAIST)Daejeon, Republic of Korea
Profile:
Jihun Oh, PhD
Associate Professor
jihun.oh@kaist.ac.kr
http://les.kaist.ac.kr
Department of Materials Science and Engineering (MSE)
Department of Energy, Environment, Water and Sustainability (EEWS)
KAIST
Profile:
Gayea Hyun
PhD Candidate
cldywkd93@kaist.ac.kr
http://fdml.kaist.ac.kr
Flexible Devices and Metamaterials Laboratory (FDML)
Department of Materials Science and Engineering (MSE)
KAIST
Profile:
Jun Tae Song, PhD
Assistant Professor
song.juntae@cstf.kyushu-u.ac.jp
http://www.cstf.kyushu-u.ac.jp/~ishihara-lab/
Department of Applied Chemistry
https://www.kyushu-u.ac.jp
Kyushu UniversityFukuoka, Japan
(END)
2020.03.13 View 18855 -
Scientists Observe the Elusive Kondo Screening Cloud
Scientists ended a 50-year quest by directly observing a quantum phenomenon
An international research group of Professor Heung-Sun Sim has ended a 50-year quest by directly observing a quantum phenomenon known as a Kondo screening cloud. This research, published in Nature on March 11, opens a novel way to engineer spin screening and entanglement. According to the research, the cloud can mediate interactions between distant spins confined in quantum dots, which is a necessary protocol for semiconductor spin-based quantum information processing. This spin-spin interaction mediated by the Kondo cloud is unique since both its strength and sign (two spins favor either parallel or anti-parallel configuration) are electrically tunable, while conventional schemes cannot reverse the sign.
This phenomenon, which is important for many physical phenomena such as dilute magnetic impurities and spin glasses, is essentially a cloud that masks magnetic impurities in a material. It was known to exist but its spatial extension had never been observed, creating controversy over whether such an extension actually existed.
Magnetism arises from a property of electrons known as spin, meaning that they have angular momentum aligned in one of either two directions, conventionally known as up and down. However, due to a phenomenon known as the Kondo effect, the spins of conduction electrons—the electrons that flow freely in a material—become entangled with a localized magnetic impurity, and effectively screen it. The strength of this spin coupling, calibrated as a temperature, is known as the Kondo temperature.
The size of the cloud is another important parameter for a material containing multiple magnetic impurities because the spins in the cloud couple with one another and mediate the coupling between magnetic impurities when the clouds overlap. This happens in various materials such as Kondo lattices, spin glasses, and high temperature superconductors.
Although the Kondo effect for a single magnetic impurity is now a text-book subject in many-body physics, detection of its key object, the Kondo cloud and its length, has remained elusive despite many attempts during the past five decades. Experiments using nuclear magnetic resonance or scanning tunneling microscopy, two common methods for understanding the structure of matter, have either shown no signature of the cloud, or demonstrated a signature only at a very short distance, less than 1 nanometer, so much shorter than the predicted cloud size, which was in the micron range.
In the present study, the authors observed a Kondo screening cloud formed by an impurity defined as a localized electron spin in a quantum dot—a type of “artificial atom”—coupled to quasi-one-dimensional conduction electrons, and then used an interferometer to measure changes in the Kondo temperature, allowing them to investigate the presence of a cloud at the interferometer end.
Essentially, they slightly perturbed the conduction electrons at a location away from the quantum dot using an electrostatic gate. The wave of conducting electrons scattered by this perturbation returned back to the quantum dot and interfered with itself. This is similar to how a wave on a water surface being scattered by a wall forms a stripe pattern. The Kondo cloud is a quantum mechanical object which acts to preserve the wave nature of electrons inside the cloud.
Even though there is no direct electrostatic influence of the perturbation on the quantum dot, this interference modifies the Kondo signature measured by electron conductance through the quantum dot if the perturbation is present inside the cloud. In the study, the researchers found that the length as well as the shape of the cloud is universally scaled by the inverse of the Kondo temperature, and that the cloud’s size and shape were in good agreement with theoretical calculations.
Professor Sim at the Department of Physics proposed the method for detecting the Kondo cloud in the co-research with the RIKEN Center for Emergent Matter Science, the City University of Hong Kong, the University of Tokyo, and Ruhr University Bochum in Germany.
Professor Sim said, “The observed spin cloud is a micrometer-size object that has quantum mechanical wave nature and entanglement. This is why the spin cloud has not been observed despite a long search. It is remarkable in a fundamental and technical point of view that such a large quantum object can now be created, controlled, and detected.
Dr. Michihisa Yamamoto of the RIKEN Center for Emergent Matter Science also said, “It is very satisfying to have been able to obtain real space image of the Kondo cloud, as it is a real breakthrough for understanding various systems containing multiple magnetic impurities. The size of the Kondo cloud in semiconductors was found to be much larger than the typical size of semiconductor devices.”
Publication:
Borzenets et al. (2020) Observation of the Kondo screening cloud. Nature, 579. pp.210-213. Available online at https://doi.org/10.1038/s41586-020-2058-6
Profile:
Heung-Sun Sim, PhD
Professor
hssim@kaist.ac.kr
https://qet.kaist.ac.kr/
Quantum Electron Correlation & Transport Theory Group (QECT Lab)
https://qc.kaist.ac.kr/index.php/group1/
Center for Quantum Coherence In COndensed Matter
Department of Physics
https://www.kaist.ac.kr
Korea Advanced Institute of Science and Technology (KAIST)
Daejeon, Republic of Korea
2020.03.13 View 17092 -
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.
(END)
2020.03.11 View 8776 -
“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.”
(END)
2020.03.05 View 10262 -
Coordination Chemistry and Alzheimer’s Disease
It has become evident recently that the interactions between copper and amyloid-b neurotoxically impact the brain of patients with Alzheimer’s disease. KAIST researchers have reported a new strategy to alter the neurotoxicity in Alzheimer’s disease by using a rationally designed chemical reagent.
This strategy, developed by Professor Mi Hee Lim from the Department of Chemistry, can modify the coordination sphere of copper bound to amyloid-b, effectively inhibiting copper’s binding to amyloid-b and altering its aggregation and toxicity. Their study was featured in PNAS last month.
The researchers developed a small molecule that is able to directly interact with the coordination sphere of copper–amyloid-b complexes followed by modifications via either covalent conjugation, oxidation, or both under aerobic conditions. The research team simply utilized copper–dioxygen chemistry to design a chemical reagent.
Answering how peptide modifications by a small molecule occur remains very challenging. The system includes transition metals and amyloidogenic proteins and is quite heterogeneous, since they are continuously being changed. It is critical to carefully check the multiple variables such as the presence of dioxygen and the type of transition metal ions and amyloidogenic proteins in order to identify the underlying mechanisms and target specificity of the chemical reagent.
The research team employed various biophysical and biochemical methods to determine the mechanisms for modifications on the coordination sphere of copper–Aꞵ complexes. Among them, peptide modifications were mainly analyzed using electrospray ionization-mass spectrometry.
Mass spectrometry (MS) has been applied to verify such peptide modifications by calculating the shift in exact mass. The research team also performed collision-induced dissociation (CID) of the target ion detected by MS to pinpoint which amino acid residue is specifically modified. The CID fragmentizes the amide bond located between the amino acid residues. This fragmental analysis allows us to identify the specific sites of peptide modifications.
The copper and amyloid-b complexes represent a pathological connection between metal ions and amyloid-b in Alzheimer’s disease. Recent findings indicate that copper and amyloid-b can directly contribute toward neurodegeneration by producing toxic amyloid-b oligomers and reactive oxygen species.
Professor Lim said, “This study illustrates the first experimental evidence that the 14th histidine residue in copper–amyloid-b complexes can be specifically modified through either covalent conjugation, oxidation, or both. Considering the neurotoxic implications of the interactions between copper and amyloid-b, such modifications at the coordination sphere of copper in amyloid-b could effectively alter its properties and toxicity.”
“This multidisciplinary study with an emphasis on approaches, reactivities, and mechanisms looks forward to opening a new way to develop candidates of anti-neurodegenerative diseases,” she added. The National Research Foundation of Korea funded this research.
2020.03.03 View 8258 -
Black Phosphorous Tunnel Field-Effect Transistor as an Alternative Ultra-low Power Switch
Researchers have reported a black phosphorus transistor that can be used as an alternative ultra-low power switch. A research team led by Professor Sungjae Cho in the KAIST Department of Physics developed a thickness-controlled black phosphorous tunnel field-effect transistor (TFET) that shows 10-times lower switching power consumption as well as 10,000-times lower standby power consumption than conventional complementary metal-oxide-semiconductor (CMOS) transistors.
The research team said they developed fast and low-power transistors that can replace conventional CMOS transistors. In particular, they solved problems that have degraded TFET operation speed and performance, paving the way to extend Moore’s Law.
In the study featured in Nature Nanotechnology last month, Professor Cho’s team reported a natural heterojunction TFET with spatially varying layer thickness in black phosphorous without interface problems. They achieved record-low average subthreshold swing values over 4-5 dec of current and record-high, on-state current, which allows the TFETs to operate as fast as conventional CMOS transistors with as much lower power consumption.
"We successfully developed the first transistor that achieved the essential criteria for fast, low-power switching. Our newly developed TFETs can replace CMOS transistors by solving a major issue regarding the performance degradation of TFETs,"Professor Cho said.
The continuous down-scaling of transistors has been the key to the successful development of current information technology. However, with Moore’s Law reaching its limits due to the increased power consumption, the development of new alternative transistor designs has emerged as an urgent need.
Reducing both switching and standby power consumption while further scaling transistors requires overcoming the thermionic limit of subthreshold swing, which is defined as the required voltage per ten-fold current increase in the subthreshold region. In order to reduce both the switching and standby power of CMOS circuits, it is critical to reduce the subthreshold swing of the transistors.
However, there is fundamental subthreshold swing limit of 60 mV/dec in CMOS transistors, which originates from thermal carrier injection. The International Roadmap for Devices and Systems has already predicted that new device geometries with new materials beyond CMOS will be required to address transistor scaling challenges in the near future. In particular, TFETs have been suggested as a major alternative to CMOS transistors, since the subthreshold swing in TFETs can be substantially reduced below the thermionic limit of 60 mV/dec. TFETs operate via quantum tunneling, which does not limit subthreshold swing as in thermal injection of CMOS transistors.
In particular, heterojunction TFETs hold significant promise for delivering both low subthreshold swing and high on-state current. High on-current is essential for the fast operation of transistors since charging a device to on state takes a longer time with lower currents. Unlike theoretical expectations, previously developed heterojunction TFETs show 100-100,000x lower on-state current (100-100,000x slower operation speeds) than CMOS transistors due to interface problems in the heterojunction. This low operation speed impedes the replacement of CMOS transistors with low-power TFETs.
Professor Cho said, “We have demonstrated for the first time, to the best of our knowledge, TFET optimization for both fast and ultra-low-power operations, which is essential to replace CMOS transistors for low-power applications.” He said he is very delighted to extend Moore’s Law, which may eventually affect almost every aspect of life and society. This study (https://doi.org/10.1038/s41565-019-0623-7) was supported by the National Research Foundation of Korea.
Publication:
Kim et al. (2020) Thickness-controlled black phosphorus tunnel field-effect transistor for low-power switches. Nature Nanotechnology. Available online at https://doi.org/10.1038/s41565-019-0623-7
Profile:
Professor Sungjae Cho
sungjae.cho@kaist.ac.kr
Department of Physics
http://qtak.kaist.ac.kr/
KAIST
Profile:
Seungho Kim, PhD Candidate
krksh21@kaist.ac.kr
Department of Physics
http://qtak.kaist.ac.kr/
KAIST
(END)
2020.02.21 View 13122