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Secondary, High Capacity Battery developed from Rice Husks
Rice husks, a waste product from rice polishing, has been successfully utilized as the silicon anode for use in high capacity lithium ion secondary batteries. The new silicon anode derived from rice husks exhibit superior output and lifespan.
Professor Choi Jang Wook (The Graduate School of Energy, Environment, Water and Sustainability (EEWS)) and Professor Park Seung Min (Department of Biochemistry) and their respective research teams separated naturally occurring, highly porous silica material within the rice husks and developed a 3-dimensional, highly porous silicon anode material.
The result of the research effort was published in the online edition of the Proceedings of the National Academy of Sciences (PNAS) journal, a world renowned journal in the field of natural sciences.
Silicon has attracted much attention as anode material for next generation lithium ion secondary batteries because it exhibits 3~5 times higher capacity than conventional graphene. The high capacity will pave the way to lithium secondary batteries with higher energy densities than conventional batteries. It is anticipated that the application of silicon batteries will yield electronic devices with a longer duration for use in addition to electronic vehicles boasting longer mileage.
The silicon anode is based on the 3-dimensional, highly porous structure of rice husks which remedies the problematic extreme volume expansion of conventional silicon anodes.
Utilization of inexpensive rice husks to create high value silicon anodes will cause a ripple effect on the industry and academia.
2013.08.23 View 9642 -
Short Wavelength, Ultra-High Speed Quantum Light Source based on Quantum Dot Developed
Professor Yong Hoon, Cho (Department of Physics) and his research team synthesized an obelisk nanostructure and successfully formed a single semiconductor quantum exhibiting high reliability to realize an ultra-high speed, highly efficient, release of quantum dots.
The result of the research effort was published in the July 5th online edition of Scientific Reports published by Nature.
Semiconductor Quantum Dots restrict electrons within a cubic boundary of few nanometers thereby exhibiting similar properties to an atom with discontinuous energy levels. Exploitation of this characteristic makes possible the development of quantum light source, critical for next generation quantum information communication and quantum encryption.
High operational temperatures, stability, rapid photon release, electric current capability, and other advantages are reasons why semiconductor quantum dots are regarded as next generation core technology.
However conventional, spontaneously formed quantum dots are densely packed in a planar structure rendering the analysis of a single quantum dot difficult and result in the poor efficiency of photon release. In addition, the internal electromagnetic effect which is caused by inter-planar stress results in low internal quantum efficiency due to the difficulty in electron-hole recombination.
Professor Cho’s research team synthesized an obelisk shaped nanostructure using nitrides that emit short wavelengths of light. The activation layer was grown on the tip of the nanostructure and the team succeeded in placing a single quantum dot on the nano-tip. The team was therefore able to confirm the ultra-high speed single photon characteristics which occur at low energy levels.
Use of unique nanostructures makes synthesis of single atomic structures without processes like patterning while enabling the release of light emitted by the quantum dot.
Using this unique method the team showed the increase in internal quantum efficiency. The electromagnetic forces apparent in thin films no longer affects the quantum dot greatly due to the obelisk structure’s reduced inter planar stress.
The newly developed quantum light source emits visible light (400nm range) and not the conventional infrared light. This characteristic makes possible it use in communication in free space and enables use of highly efficient, visible range photon detector.
Professor Cho commented that “the developed method makes quantum dot growth much easier making single photon synthesis much faster to contribute to the development of practical quantum light source.” And that “the characteristics of the obelisk nanostructure enable the easy detachment from and attachment to other substrates enabling its use in producing single chip quantum light source.”
The research was conducted under the supervision of Professor Cho. The researchers werey Jae Hyung, Kim (first author) and Yong Ho, Ko (second author), both Ph.D. candidates at KAIST. The Ministry of Science, ICT and Future Planning, the National Research Foundation, and WCU Program provided support to the research effort.
2013.08.23 View 7909
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Ultra-High Strength Metamaterial Developed Using Graphene
New metamaterial has been developed, exhibiting hundreds of times greater strength than pure metals.
Professor Seung Min, Han and Yoo Sung, Jeong (Graduate School of Energy, Environment, Water, and Sustainability (EEWS)) and Professor Seok Woo, Jeon (Department of Material Science and Engineering) have developed a composite nanomaterial. The nanomaterial consists of graphene inserted in copper and nickel and exhibits strengths 500 times and 180 times, respectively, greater than that of pure metals. The result of the research was published on the July 2nd online edition in Nature Communications journal.
Graphene displays strengths 200 times greater than that of steel, is stretchable, and is flexible. The U.S. Army Armaments Research, Development and Engineering Center developed a graphene-metal nanomaterial but failed to drastically improve the strength of the material.
To maximize the strength increased by the addition of graphene, the KAIST research team created a layered structure of metal and graphene. Using CVD (Chemical Vapor Deposition), the team grew a single layer of graphene on a metal deposited substrate and then deposited another metal layer. They repeated this process to produce a metal-graphene multilayer composite material, utilizing a single layer of graphene. Micro-compression tests within Transmission Electronic Microscope and Molecular Dynamics simulations effectively showed the strength enhancing effect and the dislocation movement in grain boundaries of graphene on an atomic level.
The mechanical characteristics of the graphene layer within the metal-graphene composite material successfully blocked the dislocations and cracks from external damage from traveling inwards. Therefore the composite material displayed strength beyond conventional metal-metal multilayer materials. The copper-graphene multilayer material with an interplanar distance of 70nm exhibited 500 times greater (1.5GPa) strength than pure copper. Nickel-graphene multilayer material with an interplanar distance of 100nm showed 180 times greater (4.0GPa) strength than pure nickel.
It was found that there is a clear relationship between the interplanar distance and the strength of the multilayer material. A smaller interplanar distance made the dislocation movement more difficult and therefore increased the strength of the material. Professor Han, who led the research, commented, “the result is astounding as 0.00004% in weight of graphene increased the strength of the materials by hundreds of times” and “improvements based on this success, especially mass production with roll-to-roll process or metal sintering process in the production of ultra-high strength, lightweight parts for automobile and spacecraft, may become possible.” In addition, Professor Han mentioned that “the new material can be applied to coating materials for nuclear reactor construction or other structural materials requiring high reliability.”
The research project received support from National Research Foundation, Global Frontier Program, KAIST EEWS-KINC Program and KISTI Supercomputer and was a collaborative effort with KISTI (Korea Institute of Science and Technology Information), KBSI (Korea Basic Science Institute), Stanford University, and Columbia University.
A schematic diagram shows the structure of metal-graphene multi-layers. The metal-graphene multi-layered composite materials, containing a single-layered graphene, block the dislocation movement of graphene layers, resulting in a greater strength in the materials.
2013.08.23 View 14148 -
Ultra High Speed Nanomaterial Synthesis Process Developed Using Laser
Dr. Jun-Yeop, Yeo and the research team led by Professor Seung-Hwan, Ko (both of the Department of Mechanical Engineering) successfully developed a process enabling the location-determinable, ultra high speed synthesis of nanomaterials using concentrated laser beams.
The result of the research effort was published as the frontispiece in the July 9th issue of Advanced Functional Materials, a world renowned material science and engineering academic journal.
Application of the technology reduced the time needed to process nanomaterial synthesis from a few hours to a mere five minutes. In addition, unlike conventional nanomaterial synthesis processes, it is simple enough to enable mass production and commercialization.
Conventional processes require the high temperatures of 900~1,000 °C and the use of toxic or explosive vapors. Complex processes such as separation after synthesis and patterning are needed for application in electronic devices. The multi-step, expensive, environmentally unfriendly characteristics of nanomaterial synthesis served as road blocks to its mass production and commercialization.
Exposing the precursor to concentrated continuous laser beam (green wavelength) resulted in the synthesis of nanowires in the desired location; the first instance in the world to accomplish this feat. The technology, according to the research team, makes possible the production, integration and patterning of nanomaterials using a single process. Applicable to various surfaces and substrates, nanowires have been successfully synthesized on flexible plastic substrates and controlled patterning on the surface of 3-dimensional structures.
Dr. Yeo commented that the research effort has “yielded the creation of a nanomaterial synthesis process capable of synthesis, integration, pattern, and material production using light energy” and has “reduced the synthesis process time of nanomaterial to one tenths of the conventional process.” Dr. Yeo continues to devise steps to commercialize the new multifunctional electronic material and methods for mass production.
The research effort, led by Dr. Yeo and Professor Ko, received contribution from Professor Hyung-Jin Sung (KAIST Department of Mechanical Engineering), Seok-Joon Hong, a Ph.D. candidate, Hyun-Wook Kang, also a Ph.D. candidate, Professor Costas Grigoropoulos of UC Berkeley, and Dr. Dae Ho Lee. In addition, the team received support from the National Research Foundation, Ministry of Knowledge Economy, Global Frontier Program, and KAIST EEWS.
Picture I: Synthesized nanomaterials produced at a desirable location by laser beams
Picture 2: Synthesized nanomaterials built on the 3D structure by using the developed technology
Picture 3: Functional electric circuit made with synthesized nanomaterials
Picture 4: Cover page of July 9th issue of Advanced Functional Materials
2013.08.23 View 9330 -
KAIST unveils foldable micro electric car, Armadillo-T
The small and light electric car completely folds in half when parking, making it a perfect fit for public or private transportation in an urban environment.
Looking for a parking space for hours at a busy shopping mall or being stuck on roads jammed with cars releasing large amounts of carbon dioxide are all-too-familiar scenes for city dwellers.
A group of researchers at the Korea Advanced Institute of Science and Technology (KAIST) recently developed a possible solution to such problems: a foldable, compact electric vehicle that can be utilized either as a personal car or part of the public transit system to connect major transportation routes within a city.
In-Soo Suh, associate professor of the Graduate School for Green Transportation at KAIST, and his research team introduced a prototype micro electric car called "Armadillo-T," whose design is based on a native animal of South America, the armadillo, a placental mammal with a leathery armor shell.
The research team imitated the animal"s distinctive protection characteristic of rolling up into a ball when facing with threat from predators. Just as armadillos hide themselves inside the shell, Armadillo-T tucks its rear body away, shrinking its original size of 2.8 meters (110 inches) down to almost half, 1.65 meters (65 inches), when folding.
Armadillo-T is a four-wheel-drive, all-electric car with two seats and four in-wheel motors. Since the motors are installed inside the wheels, and the 13.6 kWh capacity of lithium-ion battery pack is housed on the front side, the battery and motors do not have to change their positions when the car folds. This not only optimizes the energy efficiency but also provides stability and ample room to drivers and passengers.
Once folded, the small and light (weighs 450 kg) electric vehicle takes up only one-third of a 5-meter parking space, the standard parking size in Korea, allowing three of its kind to be parked. With a smartphone-interfaced remote control on the wheels, the vehicle can turn 360 degrees, enhancing drivers" convenience to park the car, even in an odd space in a parking lot, the corner of a building, for example.
Professor In-Soo Suh said, "I expect that people living in cities will eventually shift their preferences from bulky, petro-engine cars to smaller and lighter electric cars. Armadillo-T can be one of the alternatives city drivers can opt for. Particularly, this car is ideal for urban travels, including car-sharing and transit transfer, to offer major transportation links in a city. In addition to the urban application, local near-distance travels such as tourist zones or large buildings can be another example of application."
The concept car has loads of smart features on board, too: the cameras installed inside the car eliminate the need for side mirrors and increase the driver"s ability to see the car"s right and left side, thereby reducing blind spots. With a smartphone, the driver can control Armadillo-T and enable remote folding control. The car has a maximum speed of 60 km/h, and with a ten-minute fast charge, it can run up to 100 km.
Professor Suh explained that the concept of Armadillo-T was originally initiated in 2011 as he focused his research interest on the sub-A segment of personal mobility vehicles (PMVs), which are smaller and lighter than the current compact cars, as a new personalized transport mode.
"In coming years, we will see more mega-size cities established and face more serious environmental problems. Throughout the world, the aging population is rapidly growing as well. To cope with climate, energy, and limited petroleum resources, we really need to think outside the box, once again, to find more convenient and eco-friendly transportation, just as the Ford Model T did in the early 1920s. A further level of R&D, technical standards, and regulatory reviews are required to have these types of micro vehicles or PMVs on the market through test-bed evaluations, but we believe that Armadillo-T is an icon toward the future transport system with technology innovation."
The research project has been supported by the Korean government, the Ministry of Land, Infrastructure and Transport and the Korea Agency for Infrastructure Technology Advancement, since December 2012.Youtube Link: http://www.youtube.com/watch?v=8DoZH7Y-sR0
2013.08.21 View 13874 -
Two Dimensions of Value: Dopamine Neurons Represent Reward but not Aversiveness
Professor Christopher D. Fiorillo of the Bio & Brain Engineering (http://ineuron.kaist.ac.kr/web/home.html) at KAIST published a research paper in the August 2 issue of Science. The title of the paper is “Two Dimensions of Value: Dopamine Neurons Represent Reward but not Aversiveness.” The following is an introduction of his research work:
To make decisions, we need to estimate the value of sensory stimuli and motor actions, their “goodness” and “badness.” We can imagine that good and bad are two ends of a single continuum, or dimension, of value. This would be analogous to the single dimension of light intensity, which ranges from dark on one end to bright light on the other, with many shades of gray in between. Past models of behavior and learning have been based on a single continuum of value, and it has been proposed that a particular group of neurons (brain cells) that use dopamine as a neurotransmitter (chemical messenger) represent the single dimension of value, signaling both good and bad.
The experiments reported here show that dopamine neurons are sensitive to the value of reward but not punishment (like the aversiveness of a bitter taste). This demonstrates that reward and aversiveness are represented as two discrete dimensions (or categories) in the brain. “Reward” refers to the category of good things (food, water, sex, money, etc.), and “punishment” to the category of bad things (stimuli associated with harm to the body and that cause pain or other unpleasant sensations or emotions).
Rather than having one neurotransmitter (dopamine) to represent a single dimension of value, the present results imply the existence of four neurotransmitters to represent two dimensions of value. Dopamine signals evidence for reward (“gains”) and some other neurotransmitter presumably signals evidence against reward (“losses”). Likewise, there should be a neurotransmitter for evidence of danger and another for evidence of safety. It is interesting that there are three other neurotransmitters that are analogous to dopamine in many respects (serotonin, norepinephrine, and acetylcholine), and it is possible that they could represent the other three value signals.
For the research article, please visit: http://www.sciencemag.org/content/341/6145/546.abstract
For the Science 2nd issue, please visit: http://www.sciencemag.org/content/current#ResearchArticles
Illustration of Value Dimension
2013.08.08 View 7431
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2013 International Conference for the Integration of Science, Technology, and Society at KAIST (ICISTS-KAIST)
The International Conference for the Integration of Science, Technology, and Society at KAIST (ICISTS-KAIST) is a global forum organized by KAIST undergraduate students to promote the exchange of ideas and facilitate the discussion of issues that are important to science, technology, society, and higher education. The ICISTS-KAIST conference has been held annually every summer since 2005, inviting distinguished speakers and guests from all around the world to share their insights and expertise with students gathered from Korea and abroad. Last year alone, more than 300 students from 22 nations and 40 speakers participated in the event.
Originally, the ICISTS-KAIST was established by KAIST students who were inspired by the Harvard Project for Asian and International Relations (HPAIR), which is one of the Harvard’s largest annual student conferences in Asia.
This year, 335 students from 103 universities in 22 countries joined the conference that was held on August 5th-9th in Daejeon, making the 2013 ICISTS-KAIST the biggest science and engineering gathering hosted by university students in Asia. About 36% of the participants were international students.
The theme of the conference was “Perfect Alliance: Coexistence for Human Society,” in which students and speakers addressed issues on how to harmonize the speed of scientific progress with the development of important values in society, as well as to explore solutions to overcome the chasm, if any, between the boundaries of science and society.
In his opening remarks, President Steve Kang said, “Creativity and innovation are born out of openness. Therefore, it is essential for young scientists and engineers to communicate with people from different cultural and political backgrounds. Through this kind of global interaction and exchange of ideas and views, students will have an opportunity to deepen their understanding of the world and to better examine the purpose of their intellectual exploration in science and technology.” At the 2013 ICISTS-KAIST, 25 distinguished speakers participated including Walter Bender, a former director of the Media Lab at MIT and David Christian, a professor of Macquarie University in Australia.
2013.08.08 View 9570 -
Chemistry World: Interview with Professor Cafer Yavuz of EEWS Graduate School
Professor Cafer Yavuz of the Graduate School of EEWS (energy, environment, water, and sustainability) at KAIST had an interview with the Chemistry World, the print and online magazine issued by the Royal Society of Chemistry, the largest organization in Europe for advancing the chemical sciences. The link below is the article published by the magazine:
http://www.rsc.org/chemistryworld/2013/08/interview-cafer-yavuz-carbon-dioxide-capture
2013.08.07 View 7503
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KAIST's wireless Online Electric Vehicle (OLEV) runs inner city roads
For the first time anywhere, electric buses provide public transportation services and are recharged right from the road.
The Online Electric Vehicle (OLEV), developed by the Korea Advanced Institute of Science and Technology (KAIST), is an electric vehicle that can be charged while stationary or driving, thus removing the need to stop at a charging station. Likewise, an OLEV tram does not require pantographs to feed power from electric wires strung above the tram route.
Following the development and operation of commercialized OLEV trams (at an amusement park in Seoul) and shuttle buses (at KAIST campus), respectively, the City of Gumi in South Korea, beginning on August 6th, is providing its citizens with OLEV public transportation services.
Two OLEV buses will run an inner city route between Gumi Train Station and In-dong district, for a total of 24 km roundtrip. The bus will receive 20 kHz and 100 kW (136 horsepower) electricity at an 85% maximum power transmission efficiency rate while maintaining a 17cm air gap between the underbody of the vehicle and the road surface.
OLEV is a groundbreaking technology that accelerates the development of purely electric vehicles as a viable option for future transportation systems, be they personal vehicles or public transit. This is accomplished by solving technological issues that limit the commercialization of electric vehicles such as price, weight, volume, driving distance, and lack of charging infrastructure.
OLEV receives power wirelessly through the application of the “Shaped Magnetic Field in Resonance (SMFIR)” technology. SMFIR is a new technology introduced by KAIST that enables electric vehicles to transfer electricity wirelessly from the road surface while moving. Power comes from the electrical cables buried under the surface of the road, creating magnetic fields. There is a receiving device installed on the underbody of the OLEV that converts these fields into electricity. The length of power strips installed under the road is generally 5%-15% of the entire road, requiring only a few sections of the road to be rebuilt with the embedded cables.
OLEV has a small battery (one-third of the size of the battery equipped with a regular electric car). The vehicle complies with the international electromagnetic fields (EMF) standards of 62.5 mG, within the margin of safety level necessary for human health. The road has a smart function as well, to distinguish OLEV buses from regular cars—the segment technology is employed to control the power supply by switching on the power strip when OLEV buses pass along, but switching it off for other vehicles, thereby preventing EMF exposure and standby power consumption. As of today, the SMFIR technology supplies 60 kHz and 180 kW of power remotely to transport vehicles at a stable, constant rate.
Dong-Ho Cho, a professor of the electrical engineering and the director of the Center for Wireless Power Transfer Technology Business Development at KAIST, said:
“It’s quite remarkable that we succeeded with the OLEV project so that buses are offering public transportation services to passengers. This is certainly a turning point for OLEV to become more commercialized and widely accepted for mass transportation in our daily living.”
After the successful operation of the two OLEV buses by the end of this year, Gumi City plans to provide ten more such buses by 2015.
2013.08.07 View 24313 -
Next-Generation Small Satellite System Design Review (SDR) is Held
The Satellite Technology Research Center (SaTReC) held a ‘Next-Generation Small Satellite System Design Review (SDR)’ on June 26th. During the review, experts evaluated the system, bus, payload, ground station and projectile to systematically supervise the development status of the next-generation small satellite.
The ‘Next-Generation Small Satellite’ project started on June 2012, and aims to improve small satellite technology and promote space science research. This project is sponsored by the Ministry of Science and Technology and its development is supervised by ICT & Future Planning and KAIST SaTReC.
2013.08.02 View 6775 -
High Speed Nanomanufacturing Process Developed using Laser
Dr. Yeo Jun Yeop from KAIST’s Department of Mechanical Engineering, in a joint research project with Prof. Seung Hwan Ko, has developed a technology that speeds up the nanomanufacturing process by using lasers. Their research is published in the frontispiece of Advanced Functional Materials (July 9th issue).
Fig. The frontispiece of Advanced Functional Materials(July 9th issue)
The research group put a nanomaterial precursor on the board, illuminated it with a continuous-wave laser in the green wavelength range, and succeeded in synthesizing a nanowire at the point they wanted for the first time in the world.
Currently nanomaterials are difficult to mass produce and commercialize due to their complex and costly manufacturing processes which also use toxic gases. However, their new technology simplified the process and so reduced the manufacturing time from some hours to five minutes (1/10th times reduced).
Furthermore, this technology will apply regardless of the type of the board. Such nanometerials can be synthesized at any point on a flexible plastic board or even in three dimensional structures by illuminating them with a simple laser. Academics and industries expect mass production and commercialization of nanomaterials in near future.
Dr. Yeo said he intends to research further to promote early commercialization of multifunctional electronic devices by combining various nanomaterials
This research is sponsored by the National Research Foundation of Korea, the Ministry of Trade, Industry and Energy and KAIST EEWS
Fig. A nanomaterial synthesized after illuminated by lasers
Fig. A nanomaterial synthesized on a three dimensional structure using the developed technology
Fig. Functional electron device manufactured by using the synthesized nanomaterials
2013.08.02 View 8176 -
KAIST and Seoul National University Agree to Expand Cooperation in Education and Research
The presidents of two top-notch universities in Korea, KAIST and Seoul National University (SNU), met on July 23rd at the SNU campus and agreed to expand their academic cooperation to promote the univresities" mutual development.
To start, President Yeon-Cheon Oh of SNU proposed a student exchange program through which SNU students can take courses at KAIST for six months.
In return, President Steve Kang suggested that KAIST establish a liaison office on the SNU campus to facilitate better communication between two universities, thereby developing more exchange programs for research and education.Additionally, the two public universities will set up a task force to implement the agreement, conduct joint research programs, and hold regular meetings between their faculty members.President Kang said, “SNU has superb academic and research programs not only in the fields of science and technology but also in the humanities, arts, and social sciences. KAIST will surely benefit from SNU’s excellence in a broad range of academic disciplines, and SNU will have an opportunity to capitalize on KAIST’s expertise in science, engineering, and technology to enhance its growth.”At the conclusion of their consultation, the presidents expressed the hope that the agreement will strengthen the two institutions" capacity for competitiveness and globalization, preparing them to compete with leading universities in the world.
2013.07.25 View 7527