research
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Home-Grown Transparent Thin Film Transistor Developed
KAIST, Aug. 6, 2008 -- A KAIST research team led by Profs. Jae-Woo Park and Seung-Hyup Yoo of the Electrical Engineering Division has developed a home-grown technology to create transparent thin film transistor using titanium dioxide., university authorities said.The KAIST team made the technological advance in collaboration with the LCD Division of Samsung Electronics and the Techno Semichem Co., a local LCD equipment maker. Transparent thin film transistor continues to enjoy a wealth of popularity and intensive research interest since it is used in producing operating circuits including transparent display, active-matrix OLED (AMOLED) display and flexible display.
The new technology is significant in that it is based on a titanium dioxide, the first such attempt in the world, while the technologies patented by the United States and Japan are based on ZnO.
Researchers will continue to work on securing technological reliability and developing a technology to mass-produce in a large-scale chemical vapor deposition equipment for the next couple of years.
"The development of technology to produce transparent thin film transistor will help Korean LCD makers reduce its dependence on foreign technologies, as well as maintain Korea"s status as a leader of the world"s display industry," said Prof. Park.
KAIST has applied for local patent registration of the technology and the process is expected to complete by this October or November. International patents have been also applied for in the U.S., Japan and Europe.
The new technology was introduced in the latest edition of the Electron Device Letters, a journal published by the Institute of Electrical and Electronics Engineers or IEEE, a New York-based international non-profit, professional organization for the advancement of technology related to electricity. It will be presented at the International Display Workshop 2008 on Dec. 5 in Niigata, Japan.
2008.08.07 View 14203 -
Storing Stably Hydrogen Atoms in Icy Materials Discovered
KAIST, Aug. 8, 2008 -- A KAIST research team led by Prof. Huen Lee of the Department of Chemical & Biomolecular Engineering has discovered that icy organic hydrates, which contain small cages that can trap guest molecules, can be used to create and trap hydrogen atoms at higher temperatures.
The properties and reactions of single hydrogen atoms are of great scientific interest because of their inherent quantum mechanical behavior; experimentally, they can be generated and stabilized at very low temperatures (4 K) by high-energy irradiation of solid molecular hydrogen.
The finding was reported in the journal of American Chemical Society and featured in the "Editor"s Choice" in the July 11 issue of Science as a recent research highlight.
Hydrogen is a clean and sustainable form of energy that can be used in mobile and stationary applications. Hydrogen has the potential to solve several major challenges today: depletion of fossil fuels, poor air quality, and green house gas emissions.
However, the trapping of hydrogen atoms in crystalline solid matrix has never been attempted mainly because of experimental difficulties in identifying the generated hydrogen atoms with either spectroscopic or microscopic technique.
"To overcome the barriers and limitations of the existing storage approaches, we have continuously attempted to find the new hydrogen storage media such as icy powders and other related inclusion compounds," said Prof. Lee
The discovery follows the breakthrough concept Prof. Lee"s research team proposed in Nature in 2005 to use pure ice to capture and store hydrogen molecules. At moderate temperature and pressure conditions small guest molecules are entrapped in pure ice powders to form the mixed icy hydrate materials.
"Stable existence of single hydrogen molecule/radical in icy crystalline matrices may offer significant advantages in exploring hydrogen as a quantum medium because icy hydrogen hydrates can be formed at milder conditions when compared with pure solid hydrogen, which requires the ultra low temperature of 4.2 K," said Prof. Lee.
The novel design and synthesis of ionic and radicalized icy hydrates are expected to open a new field for inclusion chemistry and ice-based science and technology. Specifically, the fact that hydrogen atoms can be stably stored in icy materials might provide versatile and practical applications to energy devices including fuel cells, ice-induced reactions, and novel energy storage process, according to the KAIST professor.
2008.08.07 View 12641 -
KAIST Professors Article Featured as Cover Thesis of Biotechnology Journal
An article authored by a research team of Prof. Sang-yup Lee at the Department of Chemical and Biomolecular Engineering and Dr. Jin-Hwan Park at the KAIST Institute for the BioCentury has been featured as the cover thesis of the August 2008 issue of Trends in Biotechnology.
The paper, titled "General strategy for strain improvement by means of systems metabolic engineering," focuses on the application of systems biology for the development of strains and illustrates future prospects. Trends in Biotechnology, published by Cell Press, is one of the most prestigious review journals in the field.
Jin-Hwan Park, the primary author of the research thesis, said that the KAIST team"s research work was expected to provide substantial help to researchers involved in biotechnology industry.
The strategy has been established on the basis of the experiences gained in the actual microbial production process using the systems biology methods which his research team has recently worked on, Prof. Park said.
2008.07.24 View 13812 -
Super-Fast Internet Data Chip Developed
A KAIST research team led by Prof. Kyoung-Hoon Yang of the Electrical Engineering & Computer Science Department developed a super-fast chip that could lead to huge advancements in broadband Internet technology, the Korean Ministry of Education, Science and Technology said on Thursday (June 26).
The multiplexer chip is the first of its kind to be developed using the quantum effect of resonant tunnelling diode, according to the Ministry.
The integrated circuit chip built at the university laboratory has an operating speed of 45 gigabits per second (Gb/s), while using roughly 75 percent less energy than the previous version. The speed enables the transfer of about 4 full-length movies in one second.
The best operational broadband Internet services provide users with data transfer speed of 40 Gb/s, while most other high-speed online connections offer 10 Gb/s.
"Besides speed, the greatest achievement is low energy use," Prof. Yang said. He stressed that energy use in chips is a crucial factor because power creates heat that can melt circuits and make them inoperable.
"By cutting down on energy use, the new chips can be made smaller and with faster data transfer speed," the scientist said.
He added that efforts are underway to increase operational speed to 100 Gb/s, with energy consumption to be cut to 10 percent of current chips like the high electron mobility transistor, the heterojunction bipolar transistor and the complementary metal oxide semiconductor.
The researcher speculated that such revolutionary chips could be developed in 1-2 years and become the new benchmark in this field since existing chips have limited development capabilities.
The project has received funding from the Education-Science-Technology Ministry since 2000. The Ministry"s financial support will last until 2010.
2008.06.26 View 12103 -
New System to Generate Extreme-Ultraviolet Light Developed
A KAIST research team led by Prof. Seung-Woo Kim of the Mechanical Engineering Department developed a new system for generating coherent extreme-ultraviolet (EUV) light, school authorities announced on June 5.
The new system comes in a metallic nano-structure consisting of a two-dimensional array of gold "bow tie" elements on a sapphire plate. The new process was featured in the British journal Nature on June 5.
The properties of coherent EUV light make it a prime candidate for exciting technological applications. But, at present, the equipment needed to generate the short-wavelength light is costly and bulky. The system developed by Prof. Kim"s research team is expected to reduce both cost and bulk.
The new system uses the conventional principle of high-harmonic generation via the interaction of a femtosecond laser pulse with a gas, but adopts the novel concept of amplifying light by way of local plasmon field enhancement, according to the research team.
2008.06.10 View 12412 -
KAIST, GS Caltex Jointly Develop New Bacteria to Produce Biobutanol
KAIST and GS Caltex, Korea"s second-largest refiner, have jointly developed a new strain of bacteria to produce biobutanol, which is regarded as a promising next-generation biofuel, KAIST authorities said on Monday (June 2).
A research team led by Prof. Sang-Yup Lee of the Chemical and Biomolecular Engineering Department and researchers of GS Caltex succeeded in developing an improved strain of bacteria which enables to produce a large amount of biobutanol in the process of fermenting biomass. The research team has applied for international patent for the new technology.
Biomass refers to living and recently dead biological material that can be used as fuel or for industrial production. It usually refers to plant matter grown for use as biofuel, but it also includes plant or animal matter used for production of fibers, chemicals or heat.
In the 1970s and 1980s when scientists began researching the possibilities of alternative fuels, bacteria were used in the process of fermenting biomass. This ABE (acetone, butanol, ethanol) fermentation process yields butanol, acetone, and ethanol in a ratio of 6:3:1, respectively. Acetone produced in this process is not usable.
The newly developed technology to produce biobutanol has an advantage of lowering production cost by eliminating the process to separate acetone from butanol. This has been made possible by improving the bacteria used for the fermentation in metabolic engineering terms, and producing butanol and ethanol only in a ratio of 6:1, while curbing the generation of acetone.
In comparison with bioethanol, also a biofuel mixture which is currently under widespread use in some countries, butanol is more easily transported with gasoline and diesel through pipelines because of its lower tendency to separate from the fuel when contaminated with water. Butanol is also less corrosive than ethanol, another reason its transport through pipeline is preferable.
Global interest in full utilization of biomass and development of other alternative energy including biobutanol has deepened in recent years, as crude oil prices have skyrocketed to record levels and climate changes resulting from the excessive use of fossil fuel have been causing various problems around the world.
2008.06.04 View 11712 -
Research Outputs over Carbon Nanotube by Prof. Choi Selected as Research Highlight by ACS
Research Outputs over Carbon Nanotube by Prof. Choi Selected as Research Highlight by ACS
Research Outputs over Carbon Nanotube by Prof. Choi Selected as Research Highlight by ACS
A research team headed by Seong-Min Choi, a professor of Nuclear and Quantum Engineering, KAIST, has developed technologies to stably disperse carbon nanotube particles in aqueous solutions and organic solvents, essential for industrial applications of carbon nanotube, and discovered the dispersion characteristics of carbon nanotube. The research outputs have been published by ‘Advanced materials’ (19, 929, 2007), the most distinguished journal in Material Science field, and introduced as Research Highlight at the May 7th edition of ‘Heart Cut’ by the American Chemical Society (ACS).
A number of processes for industrial applications of carbon nanotube require the dispersion of carbon nanotube in aqueous solutions or organic solvents, and thus far, surfactant particles or DNAs have been used to disperse carbon nanotube particles. However, they have shortcomings of easy destruction of dispersion. In order to overcome such shortcomings, Prof. Choi’s team produced carbon nanotube particle-dispersed aqueous solutions by using surfactant particles and then polymerized surfactant particles absorbed to the surfaces of carbon nanotube in situ to develop carbon nanotube with hydrophile and safe surfaces. The functional carbon nanotube so obtained shows features of easy dispersion in aqueous solutions and organic solvents even after being processed, such as freeze drying, therefore, is expected to significantly contribute to the development of application technologies of carbon nanotubes. Tae-Hwan Kim and Chang-Woo Doh, both doctoral students, played key roles in the researches carried out under the auspices of the Ministry of Science and Technology (MOST) as a nuclear power R&D project, and the relevant technologies were filed for patent applications.
Figures: Carbon nanotube before polymerization (left), carbon nanotube polymerized with surfactant particles (right)
2007.05.14 View 13092 -
Maximum Yield Amino Acid-Producing Microorganism Developed with use of System Biotechnology
Maximum Yield Amino Acid-Producing Microorganism Developed with use of System Biotechnology
A team led by Sang-Yup Lee, a distinguished professor of Chemical and Biomolecular Engineering and chair professor of LG Chemical, has succeeded in developing maximum yield L-valine-producing microorganism by using System Biotechnology methods. The research results will be published at the April fourth week (April 23 - 27) edition of the Proceedings of the National Academy of Sciences (PNAS) of the USA.
Prof. Lee’s team has developed maximum yield amino acid-producing microorganism (target substance of L-valine, an essential amino-acid) by using microorganism E cell system and simulation methods.
His team produced initial producing microorganism by selectively operating necessary parts in colon bacillus genome and excavated preliminary target gene which is to newly be operated through transcriptome analysis using DNA chips. Then they performed a great amount of gene deletion experiment on computer by using MBEL979, E-cells of colon bacillus, and excavated secondary engineering targets. And they finally succeeded in developing maximum yield valine-producing microorganism that can extract 37.8 grams of valine from 100 grams of glucose by applying experiment results to the actual development of microorganism so as to achieve the optimization of metabolic flux in cells,
Prof. Lee said, “Since successfully used for the development of microorganism on a systematic system level, system biotechnology methods are expected to significantly contribute to the development of all biotechnology-relevant industries. At the beginning, we had huge obstacles in fusing IT and BT, but my team mates cleverly overcame such obstacles, hence I’m very proud of them.” The producing microorganism and its developing methods are pending international applications (PCT).
2007.04.26 View 13569 -
Prototype technologies for world highest efficiency PDP lightening developed by Prof. Choi
- Core technologies that will solve power consumption problems in PDPs- To be unveiled as invited paper at conference by Society for Information Display in May
A domestic research team has developed prototype technologies for high efficiency lightening that can significantly improve the power consumption of Plasma Display Panels (PDP).
A team headed by Kyung Cheol Choi, a professor of Electrical & Computer Science in KAiST (President Nam-Pyo Suh), has developed new cell structures and driving methods of PDP, typical digital television, which can increase the luminous efficacy of PDP four times and are to be unveiled at the conference by the Society for Information Display (SID) as an invited paper. The SID is the world largest information display society and the conference will be held at Long Beach, CA, U.S. on May 21.
Prof. Choi
2007.04.18 View 11933 -
Professor Seong-Ihl Woo Develops New High-Speed Research Method
Professor Seong-Ihl Woo Develops New High-Speed Research Method
Reduce research periods and expenses for thin film materials several ten times
Posted on the online version of Proceedings of National Academy of Sciences of the United States of America (PNAS) on January 9
A team led by Seong-Ihl Woo, a professor of KAIST Department of Chemical & Biomolecular Engineering and the director of the Center for Ultramicrochemical Process Systems, has developed a high-speed research method that can maximize research performances and posted the relevant contents on the online version of Proceedings of National Academy of Sciences of the United States of America (PNAS), a distinguished scientific journal, on January 9, 2007.
Professor Woo’s team has developed a high-speed research method that can fabricate several tens or several thousands of thin films with different compositions (mixing ratio) at the same time and carry out structural analysis and performance evaluation more than ten times faster and accurately, which leads to the shortening of the research processes of thin film materials. This is an epoch-making method that can reduce research periods and expenses several ten times or more, compared to the previous methods.
The qualities of final products of electronic materials, displays, and semi-conductors depend on the features of thin film materials. Averagely, it takes about two weeks or longer to fabricate a functional thin film and analyze and evaluate its performances. In order to fabricate thin film materials in need successfully, more than several thousand times of tests are required.
The existing thin film-fabricating equipment is expensive one demanding high-degree vacuum, such as chemical vapor deposition, sputtering, physical vapor deposition, laser evaporation, and so on. In order to fabricate thin films of various compositions with this equipment, a several million won-worth target (solid-state raw material) and precursors (volatile organic metal compound) pricing several hundreds won per gram are required. Therefore, huge amount of experiment expense is demanded for fabrication of several ten thousands of thin films with various compositions.
Professor Woo’s team has developed ‘combinatorial droplet chemical deposition’ equipment, which does not demand high-degree vacuum and is automated by computers and robots, by using a new high-speed research measure. The equipment is priced at about 1/5 of the existing equipment and easy for maintenance.
This equipment uses cheap reagents, instead of expensive raw materials. Reagents necessary to form required compositions are dissolved in water or proper solvents, and then applied by high frequencies to make several micrometer-scaled droplets (fine liquid droplet). Theses droplets are moved by nitrogen and dropped onto a substrate, which is to be fabricated into a thin film, and then subsequent thermal treatment is applied to the substrate to fabricate a thin film of required composition. At this moment, several tens or several hundreds of thin films with various compositions can be fabricated at the same time by reducing the size of thin film specimens into millimeter scale with the use of shade mask and adjusting vaporization time with masks, the moving speed of which can be adjusted. The expenses for materials necessary for the fabrication of thin films with this equipment amount to several ten thousands won per 100 grams, which is in the range of 1/100 and 1/10 of the previous methods, and the research period can be shortened into one of several tenth.
“If this new method is applied to the development of elements in the fields of core energy, material and health, which have not been discovered by the existing research methods so far, as well as researches in thin film material field, substantial effects will be brought,” said Professor Woo.
‘Combinatorial droplet chemical vaporization’ equipment is pending a domestic patent application and international patent applications at Japan and Germany. This equipment will be produced by order and provided to general researchers.
2007.02.02 View 15644
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Professor Sang-Yup Lee publishes a requested paper in Nature Biotechnology
Professor Sang-Yup Lee publishes a requested paper in Nature Biotechnology
“The era of commercialized bioplastic is coming”
Disclose an opinion as specialist at a requested paper in Nature Biotechnology, October 2006
A team led by Barbel Friedrich, Professor of Humboldt-Universitat zu Berlin, and Alexander Steinbuchel, Professor of West falische Wilhelms-Universitat Munster, found out the entire genome sequence of the typical bioplastic-producing microorganism ‘Ralstonia eutropha’ and published a paper on it in Nature Biotechnology, October 2006. As the entire genome sequence of the typical bioplactic-producing microorganism has been discovered, it is expected that the efficient production of bioplastic will be available through strain improvement at a more systematic level.
Regarding this paper, Nature Biotechnology requested world-renowned scholar Sang-Yup Lee, LG Chemical Chair-Professor of KAIST Chemical and Biomolecular Engineering Department, an expert analysis on the future of bioplastic production as a result of the deciphering of the genome sequence, and Professor Lee revealed his opinion at ‘News and Views’ in Nature Biotechnology, October 2006, issued on October 10. In the analysis, he insisted, “The deciphering of the genomes of Ralstonia means to pave the way for the improvement of strains at a system level by combining simulation through various omics and imaginary cells and engineering at a genome level. It will be possible to produce plastic with desired properties by altering the components of plastic as desired and produce bioplastic, more efficient and economical than have been reported so far, through the optimization of metabolic flow.”
Professor Lee is a world-renowned scholar in the bioplastic field, who has presented about 70 SCI papers in the field. He created a word ‘Plastic Bacteria’ at Trends in Biotechnology in 1996 and published an expert paper regarding E.Coli Plastic at Nature Biotechnology in 1997. He is now performing a research concerning the improvement of bioplastic-producing strains as an example of a research employing a systematic method for the system biological research and development project of the Ministry of Science and Technology.
The followings are the contents of Professor Lee’s paper concerning microorganism plastic published at ‘News and Views’ in Nature Biotechnology, October 2006.
- Polyhydroxyalkanoate (PHA) is a high molecule that numerous microorganisms accumulate in their own cells as energy storage substance when they are rich in carbonic resources, but poor in the other growth factors. The PHA high molecule is polyester, in which the unit substances (unit chemicals) are ester-bonded, and has been studied worldwide about twenty years before. However, PHA’s worse properties than petrochemical plastic and extremely high production cost have prevented its commercialization. The production cost of PHA was 15 dollars per kg in 1980’s, twenty times higher than the price of polypropylene. Sang-Yup Lee, LG Chemical Chair-Professor of KAIST Chemical & Biomolecular Department’s BK21 Project Group, has performed a research concerning the efficient production of microorganism plastic through the combination of metabolic engineering and fermentation process under the support of the Ministry of Science and Technology, and developed a process that lowers the production cost of PHA to 2-3 dollars per kg. He also has developed PHA-producing bacteria, efficient enough to fill plastic tightly, and named it ‘Plastic Bacteria’.
- The unprecedented rise of oil price for the past two years activated the researches on Bio-based energies and chemical production globally. PHA is also regaining attentions although the researches on it have been withered so far due to its poor economical efficiency and properties. The result of the genome deciphering of the typical plastic-producing microorganism ‘Ralstonia eutropha’ published by a German research team in Nature Biotechnology, October 2006 suggests huge meanings. That is, it will provide a blueprint over the metabolic activities of the bacteria and thus enables more systematic strain improvement.
- Eyeing on these facts, Nature Biotechnology requested Professor Sang-Yup Lee an expert analysis, and Professor Lee analyzed that there would be a dramatic development of microorganism plastic production through the application of the system biological engineering method, which is now being performed actively by Professor Lee at KAIST. In the analysis, Professor Lee revealed, “As the genome sequence has been found out, it becomes possible to establish metabolic network at a genome level, and since simulation becomes available, numberless trial and errors and experiments can be replaced with imaginary experiments rapidly. In addition, It makes the more efficient development of strains possible by fusion-analyzing the omics result such as various transcripts, proteins, metabolites, etc.” He also expected that it would be possible to produce tailor-made PHA having desired properties through metabolic engineering as well as the efficient production of plastic. Besides, he prospected that his research on the production of optically pure hydroxyl carboxyl acid, Professor Lee’s international patent right, would gain driving forces and technical development would be made rapidly at biological hydrogen production, production, dissolution and application of aromatic compounds, etc. by featuring this strain.
- Recently, Metabolic and ADM, U.S. companies, jointly started to produce PHA at a commercialization level, and Brazil having rich natural resources is commercializing PHA, following Bio-ethanol. In addition, Japan and Germany having a bunch of research performance in this field, and Australia having rich biomass are also performing consistent researches on PHA’s commercialization. Professor Lee prospected, “With the finding out of the genome sequence of the typical bioplastic-producing microorganism, competition for commercialization will be fiercer among nations through the development of efficient production systems.”
- Professor Lee prospected that as the efficient production of PHA becomes possible, the production of plastic from various renewable ingredients (cellurose, starch, suger, etc.) through microorganism fermentation would be made practically and the white biotechnologies of existing chemicals would gain more power. He also said, “Korea also will have to try to secure the production technologies and industry of Bio-based chemicals through strategic cooperation with resource powerfuls, etc. on the basis of the technical dominancy in some system metabolic engineering fields.”
- ‘News and Views’ in Nature Biotechnology is a section that publishes analyses of world-renowned specialists in the corresponding fields over the contents of some papers having great influences among papers published in the issue. KAIST Professor Sang-Yup Lee has published his second expert analysis of ‘Deciphering bioplastic production’ in the volume of October 2006, following the first paper ‘Going into the era of E.Coli plastic’.
2006.10.23 View 14974
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Professor Eunjoon Kim's team finds synapse-forming protein
Professor Eunjoon Kim’s team finds synapse-forming protein
- discover a new protein ‘NGL’ that promotes the formation of neuronal synapses
- can presume the cause of various brain disorders including schizophrenia
- will be published at Nature Neuroscience Vol. 9 in September
A new protein that promotes the formation of synapses in human brains was discovered by a Korean research team.
The team led by Eunjoon Kim, Professor of Department of Biological Sciences and Head of Creative Research Group of Synapse Formation), announced that it had discovered a new fact that NGL protein promotes the formation of neuronal synapses and this fact would be published in Nature Neuroscience Vol. 9 on September 18.
Professor Kim’s team discovered that a membrane protein named ‘NGL’ located at post synapse links with other membrane protein named netrin-G in pre synapse, acting as crosslink, and promotes the formation of a new synapse.
‘NGL’ is the second protein found to crosslink synapse, following neuoroligin. With the discovery of this new protein, the principle of synapse formation and the causes of various brain disorders can be presumed.
In the human brain, about more than 100 billion neuron cells and about 10,000 synapses compose neural circuit. A synapse is the place where innervation occurs between neuron cells. The formation of synapse induces the formation of neural circuit, and neural circuit is deeply related with various brain disorders as well as normal development of brains or brain functions.
“As netrin-G linked with NGL is related with schizonphrenia and neuoroligin and synapse crosslinking protein having a similar function with NGL is deeply related with mental retardation and autism, I think NGL is related with various brain disorders including schizophrenia.”
<Explanation of attached photos>
■ Photo1: Experiment for confirming NGL’s ability to form synapse No. 1
Mix ordinary cell (green) revealing NGL at its surface and neuron cell. Axon grows toward NGL (ordinary cell) located in the middle of ten o’clock direction and meets NGL, where NGL induces the formation of pre synapse (red) in the contacting axon.
Whether pre synapse has been formed can be told by the fluorescent dying (red) of pre synapse protein named Synapsin.
- Figure a-b: formation of synapse by NGL
- Figure c-d: transformed NGL losing synapse forming ability cannot form synapse
■ Photo 2: Experiment for confirming NGL’s ability to form synapse No. 2
When beads coated with NGL are scattered on neuron cell, the beads contact with the axon of the neuron cell (the beads are clearly visible at the phase differentiation image in the middle panel). At this time, NGL induces the formation of pre synapse (red) in the axon. Whether pre synapse has been formed can be told by the fluorescent dying (red) of pre synapse protein named SynPhy (panel a) or VGlut1 (panel b).
2006.09.21 View 14728