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KAIST Made Great Improvements of Nanogenerator Power Efficiency
The energy efficiency of a piezoelectric nanogenerator developed by KAIST has increased by almost 40 times, one step closer toward the commercialization of flexible energy harvesters that can supply power infinitely to wearable, implantable electronic devices.
NANOGENERATORS are innovative self-powered energy harvesters that convert kinetic energy created from vibrational and mechanical sources into electrical power, removing the need of external circuits or batteries for electronic devices. This innovation is vital in realizing sustainable energy generation in isolated, inaccessible, or indoor environments and even in the human body.
Nanogenerators, a flexible and lightweight energy harvester on a plastic substrate, can scavenge energy from the extremely tiny movements of natural resources and human body such as wind, water flow, heartbeats, and diaphragm and respiration activities to generate electrical signals. The generators are not only self-powered, flexible devices but also can provide permanent power sources to implantable biomedical devices, including cardiac pacemakers and deep brain stimulators.
However, poor energy efficiency and a complex fabrication process have posed challenges to the commercialization of nanogenerators. Keon Jae Lee, Associate Professor of Materials Science and Engineering at KAIST, and his colleagues have recently proposed a solution by developing a robust technique to transfer a high-quality piezoelectric thin film from bulk sapphire substrates to plastic substrates using laser lift-off (LLO).
Applying the inorganic-based laser lift-off (LLO) process, the research team produced a large-area PZT thin film nanogenerators on flexible substrates (2cm x 2cm).
“We were able to convert a high-output performance of ~250 V from the slight mechanical deformation of a single thin plastic substrate. Such output power is just enough to turn on 100 LED lights,” Keon Jae Lee explained.
The self-powered nanogenerators can also work with finger and foot motions. For example, under the irregular and slight bending motions of a human finger, the measured current signals had a high electric power of ~8.7 μA. In addition, the piezoelectric nanogenerator has world-record power conversion efficiency, almost 40 times higher than previously reported similar research results, solving the drawbacks related to the fabrication complexity and low energy efficiency.
Lee further commented,
“Building on this concept, it is highly expected that tiny mechanical motions, including human body movements of muscle contraction and relaxation, can be readily converted into electrical energy and, furthermore, acted as eternal power sources.”
The research team is currently studying a method to build three-dimensional stacking of flexible piezoelectric thin films to enhance output power, as well as conducting a clinical experiment with a flexible nanogenerator.
This research result, entitled “Highly-efficient, Flexible Piezoelectric PZT Thin Film Nanogenerator on Plastic Substrates,” was published as the cover article of the April issue of Advanced Materials. (http://onlinelibrary.wiley.com/doi/10.1002/adma.201305659/abstract)
YouTube Link: http://www.youtube.com/watch?v=G_Fny7Xb9ig
Over 100 LEDs operated by self-powered flexible piezoelectric thin film nanogenerator
Flexible PZT thin film nanogenerator using inorganic-based laser lift-off process
Photograph of large-area PZT thin film nanogenerator (3.5cm × 3.5cm) on a curved glass tube and 105 commercial LEDs operated by self-powered flexible piezoelectric energy harvester
2014.05.19 View 13617 -
Cyber Security MOU between KAIST and Yeungnam University College (YNC)
The KAIST Cyber Security Research Center and the Department of Cyber Security at Yeungnam University College (YNC) signed a memorandum of understating (MOU) on May 12, 2014 at the YNC campus to cooperate in cyber security education and technological development.
In the MOU, KAIST and YNC agreed to collaborate for the training of professional personnel and the development of new technology for the strengthening of national cyber security, as well as the common use of mutual research environments and group participation of core tasks.
As a result of the MOU interaction, the KAIST Cyber Security Research Center and the Department of Cyber Security at YNC will pursue mutual development through the joint management of the latest educational training programs for cyber security and information protection and the development of up-to-date security technology suited for nuclear energy infrastructures and regional electronic industry complexes. They will also hold joint research seminars and forums.
The Director of the Cyber Security Research Center, Professor Dae-Joon Joo (KAIST Graduate School of Information Security) commented, “With a great deal of experience in the field of cyber security, KAIST, and its excellence in education and research areas, will contribute in many ways, such as increasing the supply of expert cyber-security personnel in the Daegu-Kyungbuk region and actively participate toward greater national cyber security through this collaboration agreement.”
[Picture]
Dae-Jun Joo, KAIST Cyber Security Research Center Director (Left) and Hyun-Jig Song (Right), Chief of Industry-Academic Cooperation Foundation at Yeungnam University College, pose after signing the cooperation agreement on cyber security.
2014.05.17 View 8778 -
Dr. Sung-Gu Kim of KARI receives the 10th KAIST Jung-Hun Cho Academic Award
KAIST President Steve Kang awarded the 10th "KAIST Jung-Hun Cho Academic Award" to Dr. Sung-Gu Kim of Korea Aerospace Research Institute (KARI) along with Byeong-Sup Park, a graduate student of KAIST Aerospace Engineering, Hee-Won Chae of Korea University, and Jin-Hyung Noh of Kongju National University High School on May 13, 2014.
Dr. Sung-Gu Kim was recognized for his development of a 30-ton class reproduction cooling burner and the securing of essential factor technology for liquid-fuel rocket engines on the Naro project.
The KAIST Jung-Hun Cho Academic Award was established to commemorate Jung-Hun Cho who was killed while researching in the rocket laboratory on May 13, 2003. From 2005, young scientists from the Aerospace Engineering field have been recognized every year. One student each from KAIST, Korea University, and Kongju National University High School, where the honorary doctorate Dr. Cho attended, has been chosen as a scholarship recipient.
The KAIST Jung-Hun Cho Academic Award was established with USD 460,000 in funds donated from Cho's family.
2014.05.17 View 8811 -
KAIST leaps to 2nd place in 2014 QS Asian University Rankings
The highest record ever made by a Korean university since the rankings were published in 2009
KAIST jumped four places to rank #2 from #6 last year, following the National University of Singapore
In the "2014 Quacquarelli Symonds (QS) University Rankings: Asia," KAIST advanced four places compared to 2013 and was ranked 2nd best university in Asia.
QS, an English institution for global university evaluation, and Chosun Newspaper, a leading daily newspaper in Korea, announced the results of the QS Asia University Rankings on April 12th. The result was a record high for a Korean University since the start of annual rankings in 2009.
KAIST has consistently ranked within the top ten, ranking 7th in 2009 and 2012, and 6th in 2013. The sudden jump from the 6th to the 2nd place was attributed to the increase in the number of published papers per professor and the number of citations per paper. In particular, KAIST received high marks for research contributions, which shows that the young faculty members hired since 2006 is now becoming very productive.
For details regarding the 2014 QS University Rankings: Asia, please visit
http://www.topuniversities.com/university-rankings-articles/asian-university-rankings/top-10-universities-asia-2014.
President Steve Kang of KAIST commented, “We are reaping the rewards of recruiting some of the most promising young professors. KAIST will continue its development towards becoming one of the top ten universities in the world.”
The QS Asia University Rankings have evaluated higher education institutions of Asia for the past six years. It evaluates 491 universities across 17 nations. Criterion for evaluation includes academic evaluation (30%), number of published papers per staff (15%), citation frequency (15%), number of students per staff (20%), alumni reputation, and internationalization (10%).
Please also refer to the Korean-American Science and Technology News (KASTN), dated June 4, 2014, for further information on the rankings.
Another Rankings, Pages 4-5
Chosun Ilbo, May 12, 2014
“Chosun-QS Rankings”
KAIST Soars to 2nd Place in Asian Rakings
http://www.phy.duke.edu/~myhan/b_14-12.pdf
2014.05.14 View 12909 -
Clear Display Technology Under Sunlight Developed
The late Professor Seung-Man Yang
The last paper of the late Professor Seung-Man Yang, who was a past master of colloids and fluid mechanics
Practical patterning technology of the next generation optical materials, photonic crystals
The mineral opal does not possess any pigments, but it appears colorful to our eyes. This is because only a particular wavelength is reflected due to the regular nano-structure of its surface. The material that causes selective reflection of the light is called photonic crystals.
The deceased Professor Seung-Man Yang and his research team from KAIST’s Chemical and Biomolecular Engineering Department ha ve developed micro-pattern technology using photolithographic process. This can accelerate the commercialization of photonic crystals, which is hailed as the next generation optics material.
The research results were published in the April 16th edition of Advanced Materials, known as the most prestigious world-renowned journal in the field of materials science.
The newly developed photonic crystal micro-pattern could be used as a core material for the next generation reflective display that is clearly visible even under sunlight. Since it does not require a separate light source, a single charge is enough to last for several days.
Until now, many scientists have endeavored to make photonic crystals artificially, however, most were produced in a lump and therefore lacked efficiency. Also, the low mechanical stability of the formed structure prevented from commercialization.
In order to solve these problems, the research team has copied the nano-structure of opals.
Glass beads were arranged in the same nano-structure as the opal on top of the photoresist material undergoing photocuring by ultraviolet light. The glass beads were installed in the photoresist materials, and UV light was selectively exposed on micro regions. The remaining region was developed by photolithographic process to successfully produce photonic crystals in micro-patterns.
The co-author of the research, KAIST Chemical and Biomolecular Engineering Department’s Professor Sin-Hyeon Kim, said, “Combining the semiconductor process technology with photonic crystal pattern technology can secure the practical applications for photonic crystals.”He also predicted “This technology can be used as the key optical material that configures the next generation reflective color display device with very low power consumption.”
The late Professor Seung-Man Yang was a world-renowned expert in the field of colloids and fluid mechanics. Professor Yang published over 193 papers in international journals and continued his research until his passing in last September.
He received Du Pont Science and Technology Award in 2007, KAIST Person of the Year 2008, Gyeong-Am Academy Award in 2009, as well as the President’s Award of the Republic of Korea in March 2014. The researchers devoted the achievement of this year’s research to Professor Yang in his honor.
Research was conducted by KAIST Photonic-fluidic Integrated Devices Research Team, as a part of the Creative Research Program funded by the Ministry of Science, ICT and Future Planning, Republic of Korea.
Figure 1. Opal [left] and the nano glass bead arrangement structure within the opal [right]
Figure 2. Process chart of the photonic crystal micro-pattern formation based on photolithography
Figure 3. Opal structure [left] and inverted structure of the opal [right]
Figure 4. Photonic crystal micro-pattern in solid colors
Figure 5. Photonic crystal micro-pattern that reflects two different crystals (Red, Green) [left] and pixelated pattern of photonic crystal in three primary colors (Red, Green, Blue) [right] that is applicable to reflective displays
2014.05.14 View 11378 -
SPIE (The International Society for Optics and Photonics): Scattering Super-lens
The International Society for Optics and Photonics (SPIE), dedicated to advancing an interdisciplinary approach to the science and application of light, published online a short paper authored by a KAIST research team, Dr. Jung-Hoon Park and Professor YongKeun Park of Physics, introducing a new optical technology to observe sub-wavelength light by exploiting multiple light scattering in complex media.
For the article, please go to the link below:
SPIE: Nanotechnology
May 7th, 2014
"Scattering superlens" by Jung-Hoon Park and YongKeun Park
http://spie.org/x108298.xml
2014.05.14 View 6736 -
Professor Jae-Kyu Lee Elected to Head the Association for Information Systems
Jae Kyu Lee, HHI (Hyundai Heavy Industries, Co., Ltd.) Chair Professor, College of Business at KAIST, has been elected to lead the world major academic society, Association for Information Systems (AIS), from July 2015 to June 2016. Professor Lee will be the first Korean to serve the organization as president. From July 2014 to June 2015, he will serve as president-elect.
Currently, Professor Lee is the Director of EEWS (Energy, Environment, Water, and Sustainability) Research Center at KAIST, focusing on research and development in finding solutions to critical issues facing humanity. He also played a pivotal role in the conclusion of a memorandum of understanding between HHI and KAIST in June 2013 to establish HHI-KAIST EEWS Research Center within the KAIST campus.
The AIS is the premier professional association for individuals and organizations who lead the research, teaching, practice, and study of information systems worldwide.
2014.05.14 View 9162 -
Yong-Joon Park, doctoral student, receives the Korea Dow Chemical Award 2014
Yong-Joon Park, a Ph.D. candidate of Materials Science and Engineering at KAIST, received the Korea Dow Chemical Award 2014, a prestigious recognition of the year’s best paper produced by students in the field of chemistry and materials science.
The award ceremony took place on April 18, 2014 at Ilsan Kintex, Republic of Korea.
The Korea Dow Chemical Award is annually given by Korea Dow Chemical and the Korean Chemical Society to outstanding papers produced by graduate and postdoc students. This year, a total of nine papers were selected out of 148 papers submitted.
The title of Park’s paper is “The Development of 3D Nano-structure-based New Concept Super-elastic Materials.” This material could be used in flexible electronic devices such as displays and wearable computers.
2014.05.03 View 8112 -
KAIST ranked third in the top 100 universities under 50 years old
The Times Higher Education (THE) released on April 30, 2014 its annual ranking of 100 top universities whose history is under 50 years.
KAIST placed 3rd, holding the same spot from last year.
The (THE) 100 Under 50 ranking used 13 indicators across five factors to measure the performance of institutions: research, citations, teaching, international outlook, and industry income. The indicators included research volume and income, reputation, learning environment, staff-to-student ratio, scholarly papers produced, and the percentage of international staff as part of the institution’s faculty.
Phil Baty, editor of the Times ranking, compared younger and older universities as follows:
“Young universities are free to be more agile, lean, and risk-taking, giving them an advantage in a rapidly changing global marketplace. They are also free to offer innovative teaching and focus their research in niche, high-impact areas.”
KAIST and Pohang University of Science and Technology (ranked first) are the only Korean universities that made the ranking list.
For the full list, please go to:
http://www.timeshighereducation.co.uk/world-university-rankings/2014/one-hundred-under-fifty
This information was provided by the Times Higher Education 100 Under 50.
2014.05.03 View 10659 -
Binding Regulatory Mechanism of Protein Biomolecules Revealed
Professor Hak-Sung Kim
A research team led by Professor Hak-Sung Kim of Biological Sciences, KAIST, and Dr. Mun-Hyeong Seo, KAIST, has revealed a regulatory mechanism that controls the binding affinity of protein’s biomolecules, which is crucial for the protein to recognize molecules and carry out functions within the body.
The research results were published in the April 24th online edition of Nature Communications.
The protein, represented by enzyme, antibody, or hormones, specifically recognizes a variety of biomolecules in all organisms and implements signaling or immune response to precisely adjust and maintain important biological processes. The protein binding affinity of biomolecules plays a crucial role in determining the duration of the bond between two molecules, and hence to determine and control the in-vivo function of proteins.
The researchers have noted that, during the process of proteins’ recognizing biomolecules, the protein binding affinity of biomolecules is closely linked not only to the size of non-covalent interaction between two molecules, but also to the unique kinetic properties of proteins.
To identify the basic mechanism that determines the protein binding affinity of biomolecules, Professor Kim and his research team have made mutation in the allosteric site of protein to create a variety of mutant proteins with the same chemical binding surface, but with the binding affinity vastly differing from 10 to 100 times. The allosteric site of the protein refers to a region which does not directly bind with biomolecules, but crucially influences the biomolecule recognition site.
Using real-time analysis at the single-molecule level of unique kinetic properties of the produced mutant proteins, the researchers were able to identify that the protein binding affinity of biomolecules is directly associated with the protein’s specific kinetic characteristics, its structure opening rate.
Also, by proving that unique characteristics of the protein can be changed at the allosteric site, instead of protein’s direct binding site with biomolecules, the researchers have demonstrated a new methodology of regulating the in-vivo function of proteins.
The researchers expect that these results will contribute greatly to a deeper understanding of protein’s nature that governs various life phenomena and help evaluate the proof of interpreting protein binding affinity of biomolecules from the perspective of protein kinetics.
Professor Kim said, “Until now, the protein binding affinity of biomolecules was determined by a direct interaction between two molecules. Our research has identified an important fact that the structure opening rate of proteins also plays a crucial role in determining their binding affinity.”
[Picture]
A correlation graph of opening rate (kopening) and binding affinity (kd) between protein’s stable, open state and its unstable, partially closed state.
2014.05.02 View 9353 -
Thermoelectric generator on glass fabric for wearable electronic devices
Wearable computers or devices have been hailed as the next generation of mobile electronic gadgets, from smart watches to smart glasses to smart pacemakers. For electronics to be worn by a user, they must be light, flexible, and equipped with a power source, which could be a portable, long-lasting battery or no battery at all but a generator. How to supply power in a stable and reliable manner is one of the most critical issues to commercialize wearable devices.
A team of KAIST researchers headed by Byung Jin Cho, a professor of electrical engineering, proposed a solution to this problem by developing a glass fabric-based thermoelectric (TE) generator that is extremely light and flexible and produces electricity from the heat of the human body. In fact, 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.
To date, two types of TE generators have been developed based either on organic or inorganic materials. The organic-based TE generators use polymers that are highly flexible and compatible with human skin, ideal for wearable electronics. The polymers, however, have a low power output. Inorganic-based TE generators produce a high electrical energy, but they are heavy, rigid, and bulky.
Professor Cho came up with a new concept and design technique to build a flexible TE generator that minimizes thermal energy loss but maximizes power output. His team synthesized liquid-like pastes of n-type (Bi2Te3) and p-type (Sb2Te3) TE materials and printed them onto a glass fabric by applying a screen printing technique. The pastes permeated through the meshes of the fabric and formed films of TE materials in a range of thickness of several hundreds of microns. As a result, hundreds of TE material dots (in combination of n and p types) were printed and well arranged on a specific area of the glass fabric.
Professor Cho explained that his TE generator has a self-sustaining structure, eliminating thick external substrates (usually made of ceramic or alumina) that hold inorganic TE materials. These substrates have taken away a great portion of thermal energy, a serious setback which causes low output power.
He also commented,
"For our case, the glass fabric itself serves as the upper and lower substrates of a TE generator, keeping the inorganic TE materials in between. This is quite a revolutionary approach to design a generator. In so doing, we were able to significantly reduce the weight of our generator (~0.13g/cm2), which is an essential element for wearable electronics."
When using KAIST's TE generator (with a size of 10 cm x 10 cm) for a wearable wristband device, it will produce around 40 mW electric power based on the temperature difference of 31 °F between human skin and the surrounding air.
Professor Cho further described about the merits of the new generator:
"Our technology presents an easy and simple way of fabricating an extremely flexible, light, and high-performance TE generator. We expect that this technology will find further applications in scale-up systems such as automobiles, factories, aircrafts, and vessels where we see abundant thermal energy being wasted."
This research result was published online in the March 14th issue of Energy & Environmental Science and was entitled "Wearable Thermoelectric Generator Fabricated on Glass Fabric."
Youtube Link: http://www.youtube.com/watch?v=BlN9lvEzCuw&feature=youtu.be
[Picture Captions]
Caption 1: The picture shows a high-performance wearable thermoelectric generator that is extremely flexible and light.
Caption 2: A thermoelectric generator developed as a wristband. The generator can be easily curved along with the shape of human body.
Caption 3: KAIST’s thermoelectric generator can be bent as many as 120 times, but it still shows the same high performance.
2014.04.21 View 19840 -
Hidden Mechanism for the Suppression of Colon Cancer Identified
Published in Cell Reports : cells at the risk of causing colorectal cancer due to genetic mutation are discharged outside the colon tissue
Korean researchers have successfully identified the cancer inhibitory mechanism of the colon tissue. The discovery of the inherent defense mechanism of the colon tissues is expected to provide understanding of the cause of colorectal cancer.
The research was led by Kwang-Hyun Cho, a professor of Bio and Brain Engineering at KAIST (corresponding author) and participated by Dr. Jehun Song (the first author), as well as Dr. Owen Sansom, David Huels, and Rachel Ridgway from the Beatson Institute for Cancer Research in the UK and Dr. Walter Kolch from Conway Institute in Ireland.
The research was funded by the Ministry of Science, ICT and Future Planning and the National Research Foundation of Korea, and its results were published in the 28th March online edition of Cell Reports under the title of “The APC network regulates the removal of mutated cells from colonic crypts.”
The organism can repair damaged tissues by itself, but genetic mutations, which may cause cancer, can occur in the process of cell division s for the repair. The rapid cell division s and toxic substances from the digestive process cause a problem especially in colon crypt that has a high probability for genetic mutation.
The research team was able to find out that the colon tissues prevent cancer by rapidly discharging carcinogenic cells with genetic mutations from the colon crypt durin ga frequent tissue repair process.
This defense mechanism, which inhibits abnormal cell division s by reducing the time mutated cells reside in the crypt, is inherent in the colon.
Extensive mathematical simulation results show that the mutated cells with enhanced Wnt signaling acquire increased adhesion in comparison to the normal cells, which therefore move rapidly toward the upper part of the crypt and are discharged more easily.
If beta-catenine, the key factor in Wnt signal transduction pathway, is not degraded due to genetic mutation, the accumulated beta-catenine activates cell proliferation and increases cell adhesion. The special environment of crypt tissue and the tendency of the cells with similar adhesion to aggregate will therefore discharge the mutated cell, hence maintaining the tissue homeostasis.
In vivo experiment with a mouse model confirms the simulation results that, in the case of abnormal crypt, the cells with high proliferation in fact move slower.
Professor Cho said, “This research has identified that multicellular organism is exquisitely designed to maintain the tissue homeostasis despite abnormal cell mutation. This also proves the systems biology research, which is a convergence of information technology and bio-technology , can discover hidden mechanisms behind complex biological phenomena.”
Crypt: Epithelium, consisting of approximately 2,000 cells, forms a colon surface in the shape of a cave.
Wnt Signaling: A signal transduction pathway involved in the proliferation and differentiation of cells that are particularly important for the embryonic development and management of adult tissue homeostasis.
2014.04.17 View 11243