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"KAIST to Produce 'Janus-Faced' Nanomaterials... Paving the Way for New Materials to Selectively Capture Radioactive Pollutants"
<(From Left) Professor Ho Jin Ryu, Dr. Hyun Woo Seong, Dr. Minseok Lee>
The way has been paved for the development of multi-functional materials for applications such as removing radioactive pollutants and shielding electromagnetic waves. A KAIST research team has succeeded, for the first time in the world, in synthesizing the core raw material for fabricating asymmetric MXene, a so-called "Janus-faced" nanomaterial that can implement distinct functions due to differing atomic compositions on its two sides.
<AI-Generated Research Image>
KAIST announced on June 11th that a research team led by Professor Ho Jin Ryu from the Department of Nuclear and Quantum Engineering has successfully synthesized experimentally an asymmetric layered ceramic (a ceramic with an asymmetric structure where atomic layers are stacked on top of each other), which is a required precursor for fabricating asymmetric MXene (a two-dimensional nanomaterial with different atomic compositions on its two sides).
MXene is a two-dimensional nanomaterial with excellent electrical conductivity and high surface reactivity, drawing significant attention in various advanced technology sectors including energy storage devices and sensors. However, the MXenes developed so far possess a symmetric structure with identical atomic compositions on both sides, which has limited the functions they can implement.
In contrast, asymmetric MXenes have different atomic compositions on their two sides, allowing each side to perform distinct functions. This asymmetry enables the emergence of new properties that are difficult to achieve with conventional symmetric-structured materials. In particular, it is expected to be utilized in developing next-generation functional materials, such as adsorption filters for removing radionuclides and materials for absorbing and shielding electromagnetic waves.
Until now, however, the existence of asymmetric MXene had mostly been suggested only through computer simulations, and its actual implementation remained difficult because the raw materials required for manufacturing had not been secured.
To solve this problem, the research team applied a high-entropy material design strategy (a material design approach that mixes multiple elements to achieve new properties). By simultaneously mixing six elements—titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum (Ta), aluminum (Al), and tin (Sn)—they discovered that a stable asymmetric structure, in which the composition of the outer metal atomic layers is arranged differently due to differences in atomic size, forms naturally. This is evaluated as a new structure-forming mechanism that has never been reported in conventional MXene raw materials.
The asymmetric layered ceramic synthesized by the research team acts as a precursor (a raw material for making the final material) that can be converted into asymmetric MXene with different atomic compositions on its two sides when subjected to chemical etching (a process that selectively removes only specific atomic layers).
< Experimental Observations of the Asymmetric Ceramic Structure Synthesized in This Study >
This achievement holds great significance as it establishes the foundation for actually implementing asymmetric MXene, which had previously remained confined to theory. In particular, it presents the possibility of expanding into various advanced technology fields that were difficult to achieve with existing symmetric structures, such as radionuclide capturing, electromagnetic wave shielding, sensors, and piezoelectric devices (devices that convert pressure or vibration into electrical energy).
The research team has currently filed patent applications in South Korea, the United States, and Japan for the asymmetric layered ceramic and the asymmetric MXene utilizing it. They plan to verify the actual radioactive ion removal performance and electromagnetic wave shielding performance through follow-up studies.
Professor Ho Jin Ryu said, "This study is an instance of realizing an asymmetric atomic structure, which was difficult to achieve using conventional crystallography, through a high-entropy material design strategy. We expect that it can be developed into a core original technology in the fields of safety and the environment, such as radionuclide capturing and electromagnetic wave shielding, in the future."
Dr. Minseok Lee of KAIST (currently at the Korea Atomic Energy Research Institute) participated as the first author, and Dr. Hyun Woo Seong of KAIST (currently at the Korea Atomic Energy Research Institute) participated as a co-author. The study was published in the world-renowned scientific journal 'Nature Communications' on April 30. ※ Paper Title: An Asymmetrically Out-of-Plane Ordered MAX Phase as a Precursor for Janus MXenes, DOI : 10.1038/s41467-026-72561-y
Meanwhile, this research was conducted with support from the Nuclear Energy Basic Research Support Program of the National Research Foundation of Korea funded by the Ministry of Science and ICT.
2026.06.11 View 287 -
KAIST, Developing National Positioning Infrastructure with Wi-Fi-Based Precision Technology… A Step Toward “Location Sovereignty”
<(From Left) Prof. Dong-Soo Han, Dr. Kyuho Son, Dr. Byeongcheol Moon, Dr. Sumin Ahn, Ph.D candidate Seungwoo Chae>
A Korean research team has developed a technology that enables precise indoor positioning using only a smartphone. Developed over eight years by KAIST researchers, this technology is expected to help secure critical time in missing-person searches and is being recognized as a “location sovereignty” solution that could reshape the current location service ecosystem dominated by global big tech companies such as Google and Apple.
KAIST (President Kwang Hyung Lee) announced on the 2nd pf April that a research team led by Professor Dongsoo Han of the School of Computing has developed a core technology that can build a nationwide high-precision positioning infrastructure in a short time and at low cost by combining smartphone Wi-Fi signals with real-world address data. This achievement is the result of eight years of research, during which the team filed around ten patents to enhance the technology’s completeness.
The key feature of this technology is its use of Wi-Fi signals collected by smartphones in everyday life. It can provide precise location information anywhere in the country without requiring large-scale equipment or additional infrastructure. It also maintains high accuracy in environments where GPS is weak, such as indoors, underground, or in dense high-rise areas.
In particular, this research is seen as a challenge to the location service ecosystem currently led by global platform companies. Today, most location data worldwide is accumulated and managed by a small number of big tech firms, and Korea also relies heavily on these platforms.
Most importantly, this research establishes a foundation for independently building and managing location data generated domestically. Amid ongoing debates over exporting high-resolution national maps (1:5,000 scale spatial data detailing buildings and roads), the importance of data sovereignty is growing. This technology is drawing attention as an alternative that could reduce dependence on global big tech and realize “location sovereignty.”
The research team proposed a method that automatically combines Wi-Fi signals collected during smartphone app usage with the actual address of the location. This allows the construction of a unique “signal pattern map” (signal fingerprint) for each place, with accuracy improving as more data accumulates.
In a real-world demonstration in Daejeon, using a gas meter reading app, an average of about 30 Wi-Fi signals were detected per household in apartment complexes. This confirmed that city-scale location data can be rapidly built using this approach.
<Status of Radio Map Construction in Daejeon Using a Gas Meter Reader App>
<Address-Based Automation of Wireless Signal Collection and AI-Based Location Labeling Techniques for Collected Wireless Signals>
This technology is expected to significantly reduce location errors—previously up to hundreds of meters—in emergency situations such as missing-person searches, helping secure critical response time. It can also be applied to “location-based authentication,” allowing payments only at specific locations, thereby helping prevent financial crimes such as identity theft or unauthorized remote transactions.
Furthermore, precise location data is a key infrastructure for future AI industries, including autonomous driving, robotics, and logistics. This achievement is expected to enhance competitiveness across these sectors.
<Research Use Image (AI-Generated Image)>
Professor Dongsoo Han stated, “Positioning infrastructure is not just a convenience technology but a core asset directly linked to national data sovereignty,” adding, “It is time for the government, telecom companies, and platform providers to collaborate in building an independent national positioning infrastructure.”
This research was supported by the Ministry of Science and ICT, the National Research Foundation of Korea, the National Fire Agency, and the Korea Evaluation Institute of Industrial Technology (KEIT) (Grant No. RS-2025-02313957).
2026.04.03 View 1071 -
Seeing Black Holes More Clearly with Laser Light
<(From Left) Researcher Junyong Choi, Researcher Woosong Jeong, Professor Jungwon Kim, Researcher Jihoon Baek >
Radio telescopes are instruments that capture faint radio signals from space and convert them into images of celestial bodies. To observe distant black holes clearly, multiple radio telescopes must capture cosmic signals at exactly the same time, acting as a single unit. Research teams at KAIST have developedr a new reference signal technology that uses laser light to precisely synchronize the observation timing and phase of these telescopes.
KAIST announced on January 15th that a research team led by Professor Jungwon Kim from the Department of Mechanical Engineering—in collaboration with the Korea Astronomy and Space Science Institute, the Korea Research Institute of Standards and Science, and the Max Planck Institute for Radio Astronomy (MPIfR) in Germany—has implemented a technology that directly applies optical frequency comb lasers to radio telescope receivers.
While a typical laser emits only one color (frequency), an optical frequency comb laser emits tens of thousands of extremely accurate colors arranged at regular intervals. This appearance resembles the teeth of a comb, hence the name "frequency comb." Since the frequency of each individual "tooth" is known exactly and the intervals can be precision-tuned to the level of an atomic clock, scientists refer to it as an "ultra-precision ruler made of light."
The core of Very Long Baseline Interferometry (VLBI), a technique where multiple radio telescopes observe simultaneously, is aligning the phases of the radio signals received by each telescope as if aligning them to a single precise ruler. However, existing electronic reference signal methods faced limitations; as observation frequencies increased, precise phase calibration is becoming more difficult.
In response, the KAIST research team developed a method to deliver the optical frequency comb laser directly into the radio telescope, based on the idea of "improving the fundamental precision of phase alignment by utilizing light (lasers) from the signal generation stage." Through this, they successfully solved the problems of reference signal generation and phase calibration simultaneously within a single optical system.
If the conventional method was like using a "ruler that makes phase alignment difficult" at higher frequencies, this new technology can be compared to setting a standard with an "ultra-precision ruler that fixes the phase with extremely stable light." As a result, they have laid the foundation for distant radio telescopes to interoperate as elaborately as one giant telescope.
This technology was verified through test observations at the Korea VLBI Network (KVN) Yonsei Radio Telescope. The research team succeeded in detecting stable interference patterns (fringes) between radio telescopes and proved through actual observation that precise phase calibration is possible. Recently, this system was also installed at the KVN SNU Pyeongchang Radio Telescope, leading to expanded experiments using multiple observation sites simultaneously.
The team expects that this will not only allow for clearer imaging of black holes but also drastically reduce phase delay errors between instruments—a long-standing issue in VLBI observations.
The applications of this technology are not limited to astronomical observations. The team anticipates that it can be expanded to various advanced fields requiring precise space-time measurements, such as▲ Intercontinental ultra-precision clock comparison ▲Space geodesy ▲Deep-space probe tracking
< Illustration of the system principle (Image generated by AI) >
Professor Jungwon Kim of KAIST stated, "This research is a case where the limits of existing electronic signal generation technology were overcome by directly applying optical frequency comb lasers to radio telescopes. It will significantly contribute to improving the precision of next-generation black hole observations and advancing the fields of frequency metrology and time standards."
Dr. Minji Hyun (currently at KRISS) and Dr. Changmin Ahn from KAIST participated as co-first authors. The research findings were published on January 4th in the international academic journal Light: Science & Applications.
Paper Title: Optical frequency comb integration in radio telescopes: advancing signal generation and phase calibration
DOI: 10.1038/s41377-025-02056-w
Lead Authors: Dr. Minji Hyun (KAIST, currently KRISS), Dr. Changmin Ahn (KAIST), Jungwon Kim (KAIST)
This research was conducted with support from the National Research Council of Science & Technology (NST) Creative Alliance Project(CAP), the National Research Foundation of Korea (NRF), and the Institute of Information & Communications Technology Planning & Evaluation (IITP).
2026.01.15 View 2653 -
Flexible Sensor-Integrated RFA Needle Leads to Smarter Medical Treatment
Clinical trial of flexible sensor-integrated radiofrequency ablation (RFA) needle tip monitors physical changes and steam pop
Researchers have designed a thin polymeric sensor platform on a radiofrequency ablation needle to monitor temperature and pressure in real time. The sensors integrated onto 1.5 mm diameter needle tip have proven their efficacy during clinical tests and expect to provide a new opportunity for safer and more effective medical practices. The research was reported in Advanced Science as the frontispiece on August 5.
Radiofrequency ablation (RFA) is a minimally invasive surgery technique for removing tumors and treating cardiovascular disease. During a procedure, an unintended audible explosion called ‘steam pop’ can occur due to the increased internal steam pressure in the ablation region. This phenomenon has been cited as a cause of various negative thermal and mechanical effects on neighboring tissue. Even more, the relationship between steam pop and cancer recurrence is still being investigated.
Professor Inkyu Park said that his team’s integrated sensors reliably detected the occurrence of steam pop. The sensors also monitor rapidly spreading hot steam in tissue. It is expected that the diverse properties of tissue undergoing RFA could be checked by utilizing the physical sensors integrated on the needle.
“We believe that the integrated sensors can provide useful information about a variety of medical procedures and accompanying environmental changes in the human body, and help develop more effective and safer surgical procedures,” said Professor Park.
Professor Park’s team built a thin film type pressure and temperature sensor stack with a thickness of less than 10 μm using a microfabrication process. For the pressure sensor, the team used contact resistance changes between metal electrodes and a carbon nanotube coated polymeric membrane. The entire sensor array was thoroughly insulated with medical tubes to minimize any exposure of the sensor materials to external tissue and maximize its biocompatibility.
During the clinical trial, the research team found that the accumulated hot steam is suddenly released during steam pops and this hot air spreads to neighboring tissue, which accelerates the ablation process. Furthermore, using in-situ ultrasound imaging and computational simulations, the research team could confirm the non-uniform temperature distribution around the RFA needle can be one of the primary reasons for the steam popping.
Professor Park explained that various physical and chemical sensors for different targets can be added to create other medical devices and industrial tools.
“This result will expand the usability and applicability of current flexible sensor technologies. We are also trying to integrate this sensor onto a 0.3mm diameter needle for in-vivo diagnosis applications and expect that this approach can be applied to other medical treatments as well as the industrial field,” added Professor Park. This study was supported by the National Research Foundation of Korea.
-PublicationJaeho Park, Jinwoo Lee, Hyo Keun Lim, Inkyu Park et al. “Real-Time Internal Steam Pop Detection during Radiofrequency Ablation with a Radiofrequency Ablation Needle Integrated with a Temperature and Pressure Sensor: Preclinical and clinical pilot tests," Advanced Science (https://doi/org/10.1002/advs.202100725) on August 5, 2021
-ProfileProfessor Inkyu ParkMicro & Nano Tranducers Laboratory http://mintlab1.kaist.ac.kr/
Department of Mechanical EngineeringCollege of EngineeringKAIST
2021.10.20 View 14848 -
Professor Ji-Yun Lee, Received FAA Recognition Award
Professor Ji-Yun Lee, from the Department of Aerospace Engineering at KAIST, received the US Federal Aviation Administration (FAA) Recognition Award for her Ground-Based Augmentation System (GBAS) and her contribution to the development of satellite navigation technology.
GBAS contributes to the safety of aircraft navigation by providing flawless information with real-time location accuracy within one meter.
Professor Lee developed the monitoring software to improve the safety of GBAS users in her paper published in the International Journal of Radio Science in July of 2012.
The software will be distributed and used by many organizations including Eurocontrol following verification from the FAA technical center. It is expected to be standardized after discussions among international organizations.Professor Lee said, “As satellite navigation is applied to the infrastructure of air, marine, and ground transportation, as well as information & communications and finance, ensuring the performance and safety of the system is the most important factor. GBAS will be further developed and applied as a part of a global service system through international collaboration.”
2013.11.15 View 16317 -
A KAIST research team developed in vivo flexible large scale integrated circuits
Daejeon, Republic of Korea, May 6th, 2013–-A team led by Professor Keon Jae Lee from the Department of Materials Science and Engineering at KAIST has developed in vivo silicon-based flexible large scale integrated circuits (LSI) for bio-medical wireless communication.
Silicon-based semiconductors have played significant roles in signal processing, nerve stimulation, memory storage, and wireless communication in implantable electronics. However, the rigid and bulky LSI chips have limited uses in in vivo devices due to incongruent contact with the curvilinear surfaces of human organs. Especially, artificial retinas recently approved by the Food and Drug Administration (refer to the press release of FDA"s artificial retina approval) require extremely flexible and slim LSI to incorporate it within the cramped area of the human eye.
Although several research teams have fabricated flexible integrated circuits (ICs, tens of interconnected transistors) on plastics, their inaccurate nano-scale alignment on plastics has restricted the demonstration of flexible nano-transistors and their large scale interconnection for in vivo LSI applications such as main process unit (MPU), high density memory and wireless communication. Professor Lee"s team previously demonstrated fully functional flexible memory using ultrathin silicon membranes (Nano Letters, Flexible Memristive Memory Array on Plastic Substrates), however, its integration level and transistor size (over micron scale) have limited functional applications for flexible consumer electronics.
Professor Keon Jae Lee"s team fabricated radio frequency integrated circuits (RFICs) interconnected with thousand nano-transistors on silicon wafer by state-of-the-art CMOS process, and then they removed the entire bottom substrate except top 100 nm active circuit layer by wet chemical etching. The flexible RF switches for wireless communication were monolithically encapsulated with biocompatible liquid crystal polymers (LCPs) for in vivo bio-medical applications. Finally, they implanted the LCP encapsulated RFICs into live rats to demonstrate the stable operation of flexible devices under in vivo circumstances.
Professor Lee said, "This work could provide an approach to flexible LSI for an ideal artificial retina system and other bio-medical devices. Moreover, the result represents an exciting technology with the strong potential to realize fully flexible consumer electronics such as application processor (AP) for mobile operating system, high-capacity memory, and wireless communication in the near future."
This result was published in the May online issue of the American Chemical Society"s journal, ACS Nano (In vivo Flexible RFICs Monolithically Encapsulated with LCP). They are currently engaged in commercializing efforts of roll-to-roll printing of flexible LSI on large area plastic substrates.
Movie at Youtube Link: Fabrication process for flexible LSI for flexible display, wearable computer and artificial retina for in vivo biomedical application
http://www.youtube.com/watch?v=5PpbM7m2PPs&feature=youtu.be
Applications of in Vivo Flexible Large Scale Integrated Circuits
Top: In vivo flexible large scale integrated circuits (LSI); Bottom: Schematic of roll-to-roll printing of flexible LSI on large area plastics.
2013.06.09 View 18501 -
KAIST develops a low-power 60 GHz radio frequency chip for mobile devices
As the capacity of handheld devices increases to accommodate a greater number of functions, these devices have more memory, larger display screens, and the ability to play higher definition video files. If the users of mobile devices, including smartphones, tablet PCs, and notebooks, want to share or transfer data on one device with that of another device, a great deal of time and effort are needed.
As a possible method for the speedy transmission of large data, researchers are studying the adoption of gigabits per second (Gbps) wireless communications operating over the 60 gigahertz (GHz) frequency band. Some commercial approaches have been introduced for full-HD video streaming from a fixed source to a display by using the 60 GHz band. But mobile applications have not been developed yet because the 60 GHz radio frequency (RF) circuit consumes hundreds of milliwatts (mW) of DC power.
Professor Chul Soon Park from the Department of Electrical Engineering at the Korea Advanced Institute of Science and Technology (KAIST) and his research team recently developed a low-power version of the 60 GHz radio frequency integrated circuit (RFIC). Inside the circuit are an energy-efficient modulator performing amplification as well as modulation and a sensitivity-improved receiver employing a gain boosting demodulator.
The research team said that their RFIC draws as little as 67 mW of power in the 60 GHz frequency band, consuming 31mW to send and 36mW to receive large volumes of data. RFIC is also small enough to be mounted on smartphones or notebooks, requiring only one chip (its width, length, and height are about 1 mm) and one antenna (4x5x1 mm3) for sending and receiving data with an integrated switch.
Professor Park, Director of the Intelligent Radio Engineering Center at KAIST, gave an upbeat assessment of the potential of RFIC for future applications. What we have developed is a low-power 60-GHz RF chip with a transmission speed of 10.7 gigabits per second. In tests, we were able to stream uncompressed full-HD videos from a smartphone or notebook to a display without a cable connection (Youtube Link: http://www.youtube.com/watch?v=6PVSLBhMymc). Our chip can be installed on mobile devices or even on cameras so that the devices are virtually connected to other devices and able to exchange large data with each other."
2013.04.02 View 11476 -
Five KAIST Students Offered Internship from Qualcomm
Qualcomm Inc., a wireless telecommunications research and development company based in San Diego, California, has offered internship for five KAIST students of the Department of Electrical Engineering and Computer Science, university authorities said on Monday (Jan. 5).
The five students who are graduate and doctoral students studying communication and RFID (radio frequency identification) design will be working for six months at Qualcomm"s RFIC (radio frequency integrated circuits) Department in Santa Clara, Calif., as co-researchers. These interns will receive about $7,000 a month each with other benefits.
It is the first time that Qualcomm has offered internship for students outside the U.S., according to external relations officials at KAIST. Students who have shown outstanding research output during the internship period will be offered employment at Qualcomm.
"Qualcomm"s internship for KAIST students is designed to help young Korean talents to become professionals who will lead global advancement in the IT sector and strengthen its research network with Korea," Seung-Soo Kim, senior director of Qualcomm Korea, was quoted as saying.
Qualcomm plans to continue providing internship program for KAIST students, as well as pursuing joint research initiatives, the officials said.
2009.01.08 View 23237