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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 19816 -
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 11220 -
An Electron Cloud Distribution Observed by the Scanning Seebeck Microscope
All matters are made of small particles, namely atoms. An atom is composed of a heavy nucleus and cloud-like, extremely light electrons.
Korean researchers developed an electron microscopy technique that enables the accurate observation of an electron cloud distribution at room-temperature. The achievement is comparable to the invention of the quantum tunneling microscopy technique developed 33 years ago.
Professor Yong-Hyun Kim of the Graduate School of Nanoscience and Technology at KAIST and Dr. Ho-Gi Yeo of the Korea Research Institute of Standards and Science (KRISS) developed the Scanning Seebeck Microscope (SSM). The SSM renders clear images of atoms, as well as an electron cloud distribution. This was achieved by creating a voltage difference via a temperature gradient.
The development was introduced in the online edition of Physical Review Letters (April 2014), a prestigious journal published by the American Institute of Physics.
The SSM is expected to be economically competitive as it gives high resolution images at an atomic scale even for graphene and semiconductors, both at room temperature. In addition, if the SSM is applied to thermoelectric material research, it will contribute to the development of high-efficiency thermoelectric materials.
Through numerous hypotheses and experiments, scientists now believe that there exists an electron cloud surrounding a nucleus. IBM's Scanning Tunneling Microscope (STM) was the first to observe the electron cloud and has remained as the only technique to this day. The developers of IBM microscope, Dr. Gerd Binnig and Dr. Heinrich Rohrer, were awarded the 1986 Nobel Prize in Physics.
There still remains a downside to the STM technique, however: it required high precision and extreme low temperature and vibration. The application of voltage also affects the electron cloud, resulting in a distorted image.
The KAIST research team adopted a different approach by using the Seebeck effect which refers to the voltage generation due to a temperature gradient between two materials.
The team placed an observation sample (graphene) at room temperature (37~57℃) and detected its voltage generation. This technique made it possible to observe an electron cloud at room temperature.
Furthermore, the research team investigated the theoretical quantum mechanics behind the electron cloud using the observation gained through the Seebeck effect and also obtained by simulation capability to analyze the experimental results.
The research was a joint research project between KAIST Professor Yong-Hyun Kim and KRISS researcher Dr. Ho-Gi Yeo. Eui-Seop Lee, a Ph.D. candidate of KAIST, and KRISS researcher Dr. Sang-Hui Cho also participated. The Ministry of Science, ICT, and Future Planning, the Global Frontier Initiative, and the Disruptive Convergent Technology Development Initiative funded the project in Korea.
Picture 1: Schematic Diagram of the Scanning Seebeck Microscope (SSM)
Picture 2: Electron cloud distribution observed by SSM at room temperature
Picture 3: Professor Yong-Hyun Kim
2014.04.04 View 12957 -
Press release from the Association to Advance Collegiate Schools of Business (AACSB International): Eighty-five business schools extend their AACSB accreditation in business or accounting
The Association to Advance Collegiate Schools of Business (AACSB International) released a news announcement on April 1, 2014, saying that 85 business schools around the world extended their AACSB accreditation in business or accounting. KAIST is one of the 85 schools which is renewing its business accreditation for another five years.
Founded in 1916, AACSB International is a global accrediting organization for business schools that offer undergraduate, master’s, and doctorate degrees in business and accounting. The release said, “AACSB Accreditation is the hallmark of excellence in business education and has been earned by less than five percent of the world’s business schools. Today, there are 694 business schools in 45 countries and territories that have earned the accreditation.”
For the entirety of the release, please go to:
http://www.aacsb.edu/en/newsroom/2014/4/eighty-five-b-schools-extend-accreditation/
2014.04.02 View 6144 -
ACM Interactions: Demo Hour, March and April 2014 Issue
The
Association for Computing Machinery (ACM), the largest educational and scientific
computing society in the world, publishes a magazine called
Interactions
bi-monthly.
Interactions
is the flagship magazine
for the ACM’s Special Interest Group on Computer-Human Interaction (SIGCHI) with
a global circulation that includes all SIGCHI members.
In
its March and April 2014 issue, the Smart E-book was introduced. It was developed by Sangtae Kim, Jaejeung
Kim, and Soobin Lee at the Information Technology Convergence in KAIST
Institute, KAIST.
For
the article, please go to the link or download the .pdf files below:
Interactions,
March &
April 2014
Demo Hour: Bezel-Flipper
Bezel-Flipper
Interactions_Mar & Apr 2014.pdf
http://interactions.acm.org/archive/view/march-april-2014/demo-hour29
2014.03.28 View 9465 -
Partnership Agreement between KAIST and SK Telecom for Cyber Security
KAIST
and SK Telecom, one of the largest wireless telecommunications operators in
Korea, signed a memorandum of understanding on the industry and university cooperation
to establish a research center for cyber security on March 18, 2014.
The
center will conduct research projects to improve privacy protection, develop core
technologies needed for cyber security, train engineers and researchers, and
host seminars and conferences.
The
two organizations will implement the first joint research project on the
development of software-defined network-based solutions and universal subscriber
identity module-based personal identification solutions.
2014.03.26 View 6725 -
Extreme Tech: Nanowire "impossible to replicate" fingerprints could eliminate fraud, counterfeit goods
Research done by Professor Hyun-Joon Song of Chemistry at KAIST on
anti-counterfeit, nanoscale fingerprints generated by randomly distributed
nanowires was introduced by Extreme Tech, an online global science and technology
news.
For the articles, please go to:
Extreme Tech, March 25, 2014Nanowire ‘impossible to replicate’ fingerprints could eliminate fraud, counterfeit goods
http://www.extremetech.com/extreme/179131-nanowire-impossible-to-replicate-fingerprints-could-eliminate-fraud-counterfeit-goods
2014.03.26 View 7797 -
High Resolution 3D Blood Vessel Endoscope System Developed
Professor Wangyeol Oh of KAIST’s Mechanical Engineering Department has succeeded in developing an optical imaging endoscope system that employs an imaging velocity, which is up to 3.5 times faster than the previous systems. Furthermore, he has utilized this endoscope to acquire the world’s first high-resolution 3D images of the insides of in vivo blood vessel.
Professor Oh’s work is Korea’s first development of blood vessel endoscope system, possessing an imaging speed, resolution, imaging quality, and image-capture area. The system can also simultaneously perform a functional imaging, such as polarized imaging, which is advantageous for identifying the vulnerability of the blood vessel walls.
The Endoscopic Optical Coherence Tomography (OCT) System provides the highest resolution that is used to diagnose cardiovascular diseases, represented mainly by myocardial infarction.
However, the previous system was not fast enough to take images inside of the vessels, and therefore it was often impossible to accurately identify and analyze the vessel condition. To achieve an in vivo blood vessel optical imaging in clinical trials, the endoscope needed to be inserted, after which a clear liquid flows instantly, and pictures can be taken in only a few seconds.
The KAIST research team proposed a solution for such problem by developing a high-speed, high-resolution optical tomographic imaging system, a flexible endoscope with a diameter of 0.8 mm, as well as a device that can scan the imaging light within the blood vessels at high speed. Then, these devices were combined to visualize the internal structure of the vessel wall.
Using the developed system, the researchers were able to obtain high-resolution images of about 7 cm blood vessels of a rabbit’s aorta, which is similar size to human’s coronary arteries. The tomography scan took only 5.8 seconds, at a speed of 350 scans per second in all three directions with a resolution of 10~35㎛.
If the images are taken every 200 ㎛, like the currently available commercial vascular imaging endoscopes, a 7cm length vessel can be imaged in only one second.
Professor Wangyeol Oh said, “Our newly developed blood vessel endoscope system was tested by imaging a live animal’s blood vessels, which is similar to human blood vessels. The result was very successful.”
“Collaborating closely with hospitals, we are preparing to produce the imaging of an animal’s coronary arteries, which is similar in size to the human heart,” commented Professor Oh on the future clinical application and commercialization of the endoscope system. He added, “After such procedures, the technique can be applied in clinical patients within a few years.”
Professor Oh’s research was supported by the National Research Foundation of Korea and the Global Frontier Project by the Korean government. The research results were published in the 2014 January’s edition of Biomedical Optics Express.
Figure 1: End portion of optical endoscope (upper left)
Figure 2: High-speed optical scanning unit of the endoscope (top right)
Figure 3: High-resolution images of the inside of in vivo animal blood vessels (in the direction of vascular circumference and length)
Figure 4: High-resolution images of the inside of in vivo animal blood vessels (in the direction of the vein depth)
2014.03.25 View 10262 -
Professor Huen Lee to Receive Lifetime Achievement Award from the International Conference on Gas Hydrates
Professor Huen Lee of the Chemical and
Biomolecular Engineering Department at KAIST will receive a lifetime
achievement award at the 8th International Conference on Gas
Hydrates (ICGH) to be held from July 28, 2014 to August 2, 2014 in Beijing,
China.
Among his other scholarly and research accomplishments, Professor Lee achieved the development of natural gas by injecting
carbon dioxide and nitrogen into the layers of gas hydrates. With this
technology, ConocoPhilips, an American multinational energy corporation,
successfully extracted natural gas from the gas hydrates in the North Slope of
Alaska in the US in April 2012.
Meeting every three years in a different
country around the world, ICGH is a leading gathering of scientists and
engineers in gas hydrates. The 8th conference will be held under the
theme of “Opportunity and Challenge-Development and Utilization of Gas
Hydrates.”
2014.03.25 View 7002 -
Professor Kyung-Wook Paik Receives the Best Presentation Award from 2014 Pan Pacific Symposium
The Surface Mount Technology Association (SMTA) hosted its 19th Annual Pan Pacific Microelectronics Symposium on February 11-13, 2014 in Hawaii.
The 2014 conference, promoting international technical exchange and extensive networking among microelectronics professionals from around the world, presented over 50 papers from 17 countries.
Professor Kyung-Wook Paik of Materials Science Engineering at KAIST received the Best Presentation Award for his paper titled, “Novel Nanofiber Anisotropic Films for Nine Pitch Assembly” at the conference.
SMTA is an international network of professionals in electronics assembly technologies, including Microsystems, emerging technologies, and related business operations.
2014.03.17 View 8389 -
Tae-Wan Kim, a doctoral candidate, receives the best paper award from ECTC
The 2014 Electronic Components and Technology Conference (ECTC) will take place on May 27-30 in Florida, USA. Tae-Wan Kim, a Ph.D. candidate at the Department of Materials Science Engineering (MSE), KAIST, will receive the Intel Best Student Paper Award at the conference.ECTC is the premier international conference that brings together the best researchers and engineers in packaging, components and microelectronic systems science, technology and education in an environment of cooperation and technical exchange. The conference is sponsored by the Components, Packaging and Manufacturing Technology (CPMT) Society of IEEE (Institute of Electrical and Electronics Engineering).The paper describes research on novel nanofiber anisotropic conductive films for ultra fine pitch electronic package application, which was written under the guidance of Professor Kyung-Wook Paik of the MSE Department. In the past ten years, two of his students have received the best paper award from ECTC.
2014.03.14 View 10225 -
Visit by Sir Paul Maxime Nurse, President of the Royal Society
Sir Paul Maxime
Nurse, who is an English geneticist and cell biologist, visited KAIST and gave
a lecture entitled The Great Ideas of
Biology on March 11, 2014.
Sir Paul was awarded the 2001 Nobel Prize in
Physiology or Medicine with Leland H. Hartwell and R. Timothy Hunt for their discoveries
of protein molecules that control the division of cells in the cell cycle.
He was Professor of Microbiology at the University
of Oxford, CEO of the Imperial Cancer Research Fund and Cancer Research UK, and
President of Rockefeller University in New York. Sir Paul is currently the President of
the Royal Society as well as Director and Chief Executive of the Francis Crick
Institute.
Founded in London in 1660, the Royal Society is composed of the world’s most distinguished scientists drawn from all areas of
science, engineering, and medicine.
Below is a summary of his lecture, The Great Ideas of Biology:
Four major ideas of biology
are the theory of genes, evolution by natural selection, the proposal that the
cell is the fundamental unit of all life, and the chemical composition of a cell.
When considering the
question “what is life?” these ideas come together. The special way cells reproduce
provides the conditions by which natural selection takes place, allowing living
organisms to evolve. The organization of chemistry within the cell provides
explanations for life’s phenomena.
In addition, an emerging idea
is the nature of biological self-organization with which living cells and organisms
process information and acquire specific forms. These great ideas have
influenced one another and changed the way we perceive biology and science
today.
2014.03.11 View 9598