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Professor Jay H. Lee to receive the 2013 AIChE CAST Computing in Chemical Engineering Award
Professor Jay H. Lee of Chemical and Biomolecular Engineering Department at KAIST has won the 2013 Computing in Chemical Engineering Award of AIChE"s CAST Division (AIChE, American Institute of Chemical Engineers and CAST, Computing & Systems Technology Division). The CAST Computing in Chemical Engineering Award, sponsored by The Dow Chemical Company, is annually given to an individual who has made outstanding contributions in the application of computing and systems technology to chemical engineering.Professor Lee has been recognized for his pioneering research contributions for “novel paradigms for much improved and robust model predictive control in industrial processes.” He is currently the Head of Chemical and Biomolecular Engineering Department and Director of Brain Korea (BK) 21 Program at the department. BK21 is the Korean government’s initiative to support the growth of research universities in the nation and foster highly trained master’s and doctoral students as well as researchers. The CAST Computing in Chemical Engineering Award will be presented to Professor Jay H. Lee at the CAST Division dinner to be held at the AIChE Annual Meeting this November in San Francisco, where he will also deliver the after dinner lecture associated with this award.
2013.06.12
View 8108
Wireless electric trams at Seoul Amusement Park begin full operations.
Photo by Hyung-Joon Jun IMMEDIATE RELEASE Wireless electric trams at Seoul Amusement Park begin full operations. KAIST’s On-Line Electric Vehicle (OLEV) becomes an icon of green technology, particularly for young students who aspire to transform their nation into the “vanguard of sustainability.” Seoul, South Korea, July 19, 2011—As young students wrap up their school work before summer vacation in late July, Seoul Grand Park, an amusement park located south of Seoul, is busily preparing to accommodate throngs of summer visitors. Among the park’s routine preparations, however, there is something new to introduce to guests this summer: three wireless electric trams have replaced the old diesel-powered carts used by passengers for transportation within the park. The Korea Advanced Institute of Science and Technology (KAIST) and the city of Seoul held a ceremony this morning, July 19, 2011, to celebrate their joint efforts to adopt a green public transportation system and presented park visitors with the three On-Line Electric Vehicles (OLEVs), which will be operated immediately thereafter. Approximately one hundred people, including science high school students across the nation, attended the ceremony and had a chance to ride the trams. KAIST unveiled the prototype of an electric tram to the public in March 2010, and since then it has developed three commercial trams. The Korean government and the institute have worked on legal issues to embark on the full-scale commercialization of OLEV, and the long awaited approval from the government on such issues as standardization of the OLEV technology and road infrastructure, regulation of electromagnetic fields and electricity safety, and license and permits for vehicle eligibility, finally came through. The On-Line Electric Vehicle (OLEV) is no ordinary electric car in that it is remotely charged via electromagnetic fields created by electric cables buried beneath the road. Unlike other currently available electric cars, OLEV can travel unlimited distances without having to stop to recharge. OLEV also has a small battery onboard, which enables the vehicle to travel on roads that are not equipped with underground power cables. This battery, however, is only one-fifth of the size of a conventional electric vehicle battery, resulting in considerable savings in the cost, size, and weight of the vehicle. The OLEV project was initiated in 2009 as a method of resolving the battery problems of electric cars in a creative and disruptive way. KAIST came up with the idea of supplying electricity directly to the cars instead of depending solely on the onboard battery for power. Since then, the university has developed core technologies related to OLEV such as the “Shaped Magnetic Field in Resonance (SMFIR),” which enables an electric car to collect the magnetic fields and convert them into electricity, and the “Segment Technology,” which controls the flow of electromagnetic waves through an automatic power-on/shut-down system, thereby eliminating accidental exposure of the electromagnetic waves to pedestrians or non-OLEV cars. According to KAIST, three types of OLEV have been developed thus far: electric buses, trams, and sport utility vehicles (SUVs). The technical specifications of the most recently developed OLEV (an electric bus), the OLEV research team at the university said, are as follows: · Power cables are buried 15cm beneath the road surface. · On average, over 80% power transmission efficiency is achieved. · The distance gap between the road surface and the underbody of the vehicle is 20cm. · The OLEV bus has a maximum electricity pickup capacity of 100kW. · The OLEV bus complies with international standards for electromagnetic fields (below 24.1 mG). The eco-friendly electric trams at Seoul Grand Park consume no fossil fuels and do not require any overhead wires or cables. Out of the total circular driving route (2.2km), only 16% of the road, 372.5m, has the embedded power lines, indicating that OLEV does not require extensive reconstruction of the road infrastructure. The city government of Seoul signed a memorandum of understanding with KAIST in 2009 as part of its initiatives to curtail emissions from public transportation and provide cleaner air to its citizens. Both parties plan to expand such collaboration to other transportation systems including buses in the future. KAIST expects the OLEV technology to be applied in industries ranging from transportation to electronics, aviation, maritime transportation, robotics, and leisure. There are several ongoing international collaborative projects to utilize the OLEV technology for a variety of transportation needs, such as inner city commute systems (bus and trolley) and airport shuttle buses, in nations including Malaysia, US, Germany, and Denmark. # # # More information about KAIST’s On-Line Electric Vehicle can be found at http://olev.co.kr/en/index.php. For any inquiries, please contact Lan Yoon at 82-42-350-2295 (cell: 82-10-2539-4303) or by email at hlyoon@kaist.ac.kr.
2011.07.22
View 13012
KAIST paves the way to commercialize flexible display screens
Source: IDTechEX, Feb. 28, 2011 KAIST paves the way to commercialize flexible display screens 28 Feb 2011 Transparent plastic and glass cloths, which have a limited thermal expansion needed for the production of flexible display screens and solar power cells, were developed by researchers at KAIST (Korea Advance Institute of Science & Technology). The research, led by KAIST"s Professor Byoung-Soo Bae, was funded by the Engineering Research Center under the initiative of the Ministry of Education, Science and Technology and the National Research Foundation. The research result was printed as the cover paper of "Advanced Materials". Professor Bae"s team developed a hybrid material with the same properties as fiber glass. With the material, they created a transparent, plastic film sheet resistant to heat. Transparent plastic film sheets were used by researchers all over the world to develop devices such as flexible displays or solar power cells that can be fit into various living spaces. However, plastic films are heat sensitive and tend to expand as temperature increases, thereby making it difficult to produce displays or solar power cells. The new transparent, plastic film screen shows that heat expansion index (13ppm/oC) similar to that of glass fiber (9ppm/oC) due to the presence of glass fibers; its heat resistance allows to be used for displays and solar power cells over 250oC. Professor Bae"s team succeeded in producing a flexible thin plastic film available for use in LCD or AMOLED screens and thin solar power cells. Professor Bae commented, "Not only the newly developed plastic film has superior qualities, compared to the old models, but also it is cheap to produce, potentially bringing forward the day when flexible displays and solar panels become commonplace. With the cooperation of various industries, research institutes and universities, we will strive to improve the existing design and develop it further." http://www.printedelectronicsworld.com/articles/kaist_paves_the_way_to_commercialize_flexible_display_screens_00003144.asp?sessionid=1
2011.03.01
View 10811
KAIST developed a plastic film board less sensitive to heat.
The research result was made the cover of magazine, Advanced Materials and is accredited to paving the way to commercialize flexible display screens and solar power cells. Transparent plastic and glass cloths, which have a limited thermal expansion needed for the production of flexible display screens and solar power cells, were developed by Korean researchers. The research, led by KAIST’s Professor Byoung-Soo Bae, was funded by the Engineering Research Center under the initiative of the Ministry of Education, Science and Technology and the National Research Foundation. The research result was printed as the cover paper of ‘Advanced Materials’ which is the leading magazine in the field of materials science. Professor Bae’s team developed a hybrid material with the same properties as fiber glass. With the material, they created a transparent, plastic film sheet resistant to heat. Transparent plastic film sheets were used by researchers all over the world to develop devices such as flexible displays or solar power cells that can be fit into various living spaces. However, plastic films are heat sensitive and tend to expand as temperature increases, thereby making it difficult to produce displays or solar power cells. The new transparent, plastic film screen shows that heat expansion index (13ppm/oC) similar to that of glass fiber (9ppm/oC) due to the presence of glass fibers; its heat resistance allows to be used for displays and solar power cells over 250oC. Professor Bae’s team succeeded in producing a flexible thin plastic film available for use in LCD or AMOLED screens and thin solar power cells. Professor Bae commented, “Not only the newly developed plastic film has superior qualities, compared to the old models, but also it is cheap to produce, potentially bringing forward the day when flexible displays and solar panels become commonplace. With the cooperation of various industries, research institutes and universities, we will strive to improve the existing design and develop it further.”
2011.01.05
View 10909
International Workshop on EEWS 2010 was held.
On October 7 and 8th at Fusion Hall of KI Building, KAIST, the 2010 International Workshop on EEWS (Energy, Environment, Water, and Sustainability) was held. The third to be held, forty national and international academic professionals including Mark Shannon, professor at University of Illinois at Urbana-Champaign, Domen Kazunari, Tokyo University professor, Dong Sub Kim, CTO of SK Energy and Doyoung Seung, Senior Vice President of GS Caltex, participated at this year’s workshop. In twelve sessions, themes including Artificial Photosynthesis, Wireless Power Transfer, Green Aviation, Safe Nuclear Fuel Reuse, Fuel Cells in Action, LED 2.0, Foundation of Energy-Water Nexus, and Flexible Battery & Solar Cell were presented and discussed. “Through this workshop, current EEWS policy and research progress from different countries and the future of related technologies will be foreseen,” said Jae Kyu Lee, Dean of KAIST EEWS Initiative. “I hope it became an opportunity to create cooperative relationships with leading researchers.” EEWS is a research project conducted by KAIST to solve global issues that mankind faces today such as depletion of energy, environmental pollution, water shortage, and sustainability.
2010.10.15
View 12629
International Center was built to promote greater exchanges and collaborations between the international community and KAIST.
On July 9, 2010, KAIST held an opening ceremony for the construction of International Center. The Center will serve as an internal and external liaison for the university, providing a source of assistance to faculty, administrators, and students on matters related to international activities and initiatives. It will also pursue greater exchanges and collaborations between the international community and KAIST. The facility accommodates various meetings, exhibitions, library, language services, and other amenities. The International Cooperation Team of KAIST will be moved into this building and provide a variety of services, such as immigration regulations, cultural adjustment, employment, to assist international students, scholars, faculty, and staff at KAIST, as well as Korean students seeking opportunities to study, work, or travel abroad. An international nursery school will also be inside the building so that foreign faculty and students with children can have convenience and quality child care while they are teaching or studying. At the center will be held many different kinds of international event—one among them is KAIST-ONE, a festival held twice a year in spring and fall to introduce and share culture, education, and food of the global community at KAIST.
2010.07.19
View 9573
The 8th International Conference on Metabolic Engineering was held on June 13-18, 2010 in Jeju Island, South Korea.
From left to right, top row: Distinguished Professor and the conference chair Sang Yup Lee, Sang-Hyup Kim - Secretary to the President of Korea, Dr. Jay Keasling, Dr. Greg Stephanopoulos. Left to right, bottom row: Dr. William Provine, Dr. Terry Papoutsakis, Dr, Jens Nielsen, Dr. Lars Nielsen. The importance of industrial biotechnology that produces chemicals and materials from renewable biomass is increasing due to climate change and the dearth of natural resources. Industrial biotechnology refers to a technology that allows sustainable bio-based production of chemicals and materials that could enrich human"s lives using microorganisms. This is where metabolic engineering comes into play for successful application of microorganisms, in which they are engineered in our intended way for improved production capability. The 8th International Conference on Metabolic Engineering, the longest running conference of its kind, was held on June 13-18, 2010 at the International Convention Center in Jeju Island, South Korea. Distinguished Professor Sang Yup Lee of KAIST, Dean of College of Life Science and Bioengineering and Co-Director of Institute for the BioCentury, chaired the conference with the main theme of "metabolic engineering for green growth." With 300 delegates selected by the committee, papers on production of biofuels, chemicals, biopolymers, and pharmaceutics and the development of fundamental metabolic engineering techniques were presented at the conference along with examples of successful commercialization of products developed by several global companies. Sang Hyup Kim, Secretary to the President of Korea, gave an opening plenary lecture entitled "Korean green growth initiative," to inform experts from around the globe of the leadership on green growth in Korea. Young Hoon Park, President of Korea Research Institute of Bioscience and Biotechnology (KRIBB, Korea) delivered his congratulatory address. Sang Hyup Kim said, "Hosting an international conference in Korea on metabolic engineering, which forms a core technology necessary for the development of environmentally friendly processes for producing chemicals and biofuels from renewable biomass, is very meaningful as green growth is a big issue around the globe. This is a great chance to show the excellence of Korea"s green growth associated technology to experts in metabolic engineering and industrial biotechnology." A total of 47 invited lectures in this conference included recent and important topics, for instance, "Synthetic biology for synthetic fuels" by Dr. Jay Keasling from the Joint BioEnergy Institute (USA), "Microbial oil production from renewable feedstocks" by Dr. Greg Stephanopoulos from MIT (USA), "Yeast as a platform cell factory for production of fuels and chemicals" by Dr. Jens Nielsen from Chalmers University (Sweden), "Mammalian synthetic biology - from tools to therapies" by Dr. Martin Fussengger from ETH (Switzerland), "Building, modeling, and applications of metabolic and transcriptional regulatory networks at a genome-scale" by Dr. Bernhard Palsson from the University of California - San Diego (USA), "Genome analysis and engineering Eschericha coli for sucrose utilization" by Dr. Lars Nielsen from the University of Queensland (Australia), "Artificial microorganisms by synthetic biology" by Dr. Daniel Gibson from JCVI (USA), and "Metabolomics and its applications" by Dr. Masaru Tomita from Keio University (Japan). From Korea, Dr. Jin Hwan Park from the research group of Dr. Sang Yup Lee at KAIST presented "Systems metabolic engineering of Escherichia coli for amino acid production," and Dr. Ji Hyun Kim from KRIBB presented "Genome sequencing and omics systems analysis of the protein cell factory of Escherichia coli". Global companies involved in biorefinery presented their recent research outcomes with emphasis on commercialized technologies. They included "Metabolic and process engineering for commercial outcomes" by Dr. William Provine from DuPont (USA), "Direct production of 1,4-butanediol from renewable feedstocks" by Dr. Mark Burk from Genomatica (USA), "Development of an economically sustainable bioprocess for the production of bio 1,2-propanediol" by Dr. Francis Voelker from Metabolic Explorer (France), "Biotechnology to the bottom-line: low pH lactic acid production at industrial scale" by Dr. Pirkko Suominen from Cargill (USA), "Bioisoprene™: traditional monomer, traditional chemistry, sustainable source" by Dr. Gregg Whited from Danisco (USA) and "Efficient production of pharmaceuticals by engineered fungi" by Dr. Roel Bovenberg from DSM (Netherlands). This biennial conference also presented the International Metabolic Engineering Award (expanded version of the previous Merck Metabolic Engineering Award) to the best metabolic engineer in the world. The 2010 International Metabolic Engineering Award went to Dr. E. Terry Papoutsakis from the University of Delaware (USA) who has contributed to the production of biobutanol through the metabolic engineering of Clostridia in the last three decades, and he gave an award lecture. Dr. Sang Yup Lee, the current chair of the upcoming conference, was the previous recipient of this award at the last metabolic engineering conference in 2008. In addition to the invited lectures, a total of 156 carefully selected poster papers were chosen for presentation, and awards were presented to the best posters after rigorous review by the committee members. Such awards included "The 2010 Metabolic Engineering Best Poster Award" and the "2010 Young Metabolic Engineer Award" from the Metabolic Engineering conference, and prestigious international journal awards, including "Wiley Biotechnology Journal Best Poster Award", "Wiley Biotechnology and Bioengineering Best Poster Award" and "Elsevier Metabolic Engineering Best Paper Award." Dr. Catherine Goodman, a senior editor of Nature Chemical Biology, also presented the "Nature Chemical Biology Best Poster Award on Metabolic Engineering." Regarding this conference, Dr. Sang Yup Lee, the conference chair, said, "This conference is the best international conference in the field of metabolic engineering, which is held every two years, and Korea is the first Asian country to host it. All the experts and students spend time together from early breakfast to late poster sessions, which is a distinct feature of this conference. Although the number of delegates had typically been limited to 200, around 300 delegates were selected this year to accept more attendees from many people who have been interested in metabolic engineering. Also, it is very fitting that "green growth" is the main topic of this conference because Korea is playing a key role in this field. I"m grateful to the Lotte Scholarship Foundation, COFCO, GS Caltex, Bioneer, US DOE, US NSF, Daesang, CJ Cheiljedang, Genomatica and DuPont who provided us with generous financial support that allowed the successful organization of this conference." The conference was organized by the Systems Biology Research Project Team supported by the Ministry of Eduction, Science and Technology (MEST), Microbial Frontier Research Project Group, World Class University Project Group at KAIST, Institute for the BioCentury at KAIST, Korean Society for Biotechnology and Bioengineering, and the Engineering Conference International (ECI) of the United States. Inquiries: Professor Sang Yup Lee (+82-42-350-3930), industrialbio@gmail.com
2010.06.25
View 15332
President of Israel visited KAIST on June 9, 2010.
President of Israel, Shimon Peres, visited KAIST today on June 9, 2010 to witness the development of science and technology in Korea and explore ways of establishing collaboration and cooperation with industries and universities between Korea and Israel. President Peres led a delegation consisted of the Israeli Mister of Industry, Trade, and Labor, the Minister of Communication, and 60 business leaders from the top companies in the security, infrastructure, communication, high-tech, and water industries. Upon their arrival to the campus, the Israeli delegation was greeted by KAIST’s humanoid robot, “HUBO,” and then moved to its branch campus, IT Convergence Campus, for a ride of Online Electric Vehicle (OLEV) that has been developed by KAIST. The OLEV receives the necessary power through the cable lines buried underground, so it can be provided with a constant and continuous supply of electricity while running or stopping. Between roads and OLEVs is nothing but space. There is no electrical wires intricately crossed underbody of the electric car or above the road. The pick-up equipment installed beneath the body of the electric car collects magnetic fields created around the underground cables, which then converts the filed into electricity. The OLEV’s wireless, non-contact charging system made it possible for a battery currently used for hybrid or pure electric cars on the market to be smaller and cheaper. President Peres expressed a great interest in the technology applied to the OLVE, quoting, “the OLEV system is indeed very impressive.” He talked about efforts being made in Israel with respect to the development of electric cars. The country plans to replace the conventional transportation system with electric cars by constructing a network of battery exchange stations and roadside charge points which allow the cars to be charged whenever they are parked. “Despite the different approach taken by the two nations for the development of electric cars, I believe that transforming the automobile industry from combustion engine to electric system is the right direction we should all follow. Without addressing the current transportation system that heavily dependent on natural resources, we will not be able to promote “green growth on a global scale,” added President Peres. In addition to electric cars, President Peres took up a considerable portion of his time to exchange ideas on how to expand cooperative relations between universities in Korea and Israel, specifically in the area of space, biotechnology, nanotechnology, high-tech, renewable and alternative energy, and the EEWS initiatives that have been implemented by KAIST to find answers to global issues such as climate change and depletion of natural resources. The EEWS stands for energy, environment, water, and sustainability. In response, the president of KAIST pledged to set up a stronger and greater tie with research universities in Israel, particularly called for more collaboration between KAIST and Technion-Israel Institute of Technology. Also, the Israeli delegation had a tour for several Korean research and development centers in Daedeok Innopolis, located in the City of Daejeon, which is the 2nd largest science and research complex in Korea. Shimon Peres, the 9th president of Israel, held many of important government positions in Israel, among other things, Prime Minster and Minister of Defense. He won Nobel Peace Prize in 1994, together with Yitzhak Rabin and Yasser Arafat for the conclusion of a peace agreement, Oslo Accords, between Israel and Palestine Liberation Organization.
2010.06.09
View 12989
KAIST listed 27 research subjects for EEWS.
The Office of EEWS Initiative at KAIST announced 27 research projects to be implemented in 2010. The EEWS stands for energy, environment, water, and suitability. KAIST established the EEWS Office in 2008 in efforts to solve problems facing mankind today such as depletion of natural resources, environment pollution, climate changes, water shortages, and sustainable growth. On the nationwide, the Korean government has taken initiatives to support “green growth” and “green technology” projects. In 2009, the EEWS Office supported 24 research projects and received 28 patent rights, 6 patent registrations, and 57 Science Citation Index (SCI) papers. This year, the office chose 27 research subjects including 7 flagship projects: flexible lithium polymer batteries, spent nuclear fuel recycling, highly efficient bio-butanol, liquid electrolyte battery solid oxide fuel cell, LED lighting, artificial photosynthesis, and nano organic solar cells. New research topics begun this year include energy-saving desalination system and ultra-thin film of silicon solar cells. Jae-Kyu Lee, Dean of EEWS Initiative Office said, “Having multiple volume of small-scaled, topic-focused research projects will encourage us to come up with large-scale convergence research projects. In so doing, we can explore new frontiers of science and technology and serve as the new growth engine for the development of green technology and industry in Korea.” All the research projects selected will be subject to evaluations. For example, the EEWS Initiative Office will host an international workshop in September 2010 where it plans to introduce and evaluate the ongoing research projects.
2010.05.19
View 8742
1,180 meters of fence on campus facing Gap-Chun River will be gone by June 2010.
KAIST and the City of Daejeon have taken on a project to remove a stretch of fence on campus that faces Gap-Chun River, making the campus accessible to all citizens and visitors. The work will last for three months beginning on April 5th and throughout June 2010. Gradually, KAIST plans to remove the entire fence surrounding the campus within a few years. The city government has encouraged government and public organizations in Daejeon to open up their public space to citizens and visitors as part of its initiatives to reach out to local communities. As of December 2008, seven public organizations have completed to rid of their boundary markers, and eight more organizations will make their gardens and campus available to the public by the end of this year. All the expenses related to the removal of the fence will be borne by the city government. At the place where the fence is knocked down will become a park so that neighbors and visitors can come and rest. A school official said, “This is an important campaign for us because it promotes more exchanges between the university and local community. Our campus has rich green foliage, and visitors will surely enjoy it. By opening up our campus to the public, we hope to return to the society what we have received as a public institution and create a forum where art, science, and technology meet together.” In addition to the removal of the fence, KAIST and the city government will install flowerbeds, health facilities, and walking trails for the citizens.
2010.04.26
View 8310
A KAIST graduate to become a professor at a prestigious university in UAE
A KAIST graduate to become a professor at a prestigious university in UAE Dr. Jerald Yoo, a KAIST graduate, has been appointed as an assistant professor at the Masdar Institute of Science and Technology (MIST) in Abu Dhabi, United Arab Emirates (UAE), by the recommendation of the Massachusetts Institute of Technology (MIT) since April 1, 2010. The MIST is a private, not-for-profit, independent, research-driven institute developed with the support and cooperation of MIT and the Abu Dhabi government, which was opened in September 2009. Currently, at the school, there are 25 professors and 100 students from 22 countries around the world. The institute has a campus in Masdar City where the Abu Dhabi government plans to nurture it as a “place for zero carbon emissions.” According to an agreement between the MIST and MIT, Professor Yoo will teach and work on co-research projects at MIT for one year beginning in May 2010 and then working at the MIST thereafter. Professor Yoo received all of his degrees (BS, MS, and Ph.D.) from KAIST majoring in electrical engineering and earned his doctoral degree in January 2010. His research works included developing a wearable patch to monitor bio signals with an application of wearable sensor networks and low energy electronic circuit technologies. During his doctoral study, Professor Yoo published papers at the IEEE International Solid-State Circuits Conference (ISSCC) and in journals of IEEE Solid-State Circuits Society (SSCS). Professor Yoo said, "The wearable health care system is certainly necessary to improve the quality of our lives, and the field should receive a sustaining support for further research. I will do my best to continuously produce valuable research results and hope that my research works will be helpful for an academic exchange between South Korea and Abu Dhabi.” About the Masdar Institute of Science and Technology (MIST) in Abu Dhabi: http://www.masdar.ac.ae/ The Masdar Institute is the centerpiece of the Masdar Initiative, a landmark program announced in April 2006 by the government of Abu Dhabi to establish an entirely new economic sector dedicated to alternative and sustainable energy. Masdar is a highly-strategic initiative with primary objectives of: helping drive the economic diversification of Abu Dhabi; maintaining and expanding Abu Dhabi"s position in evolving global energy markets; positioning Abu Dhabi as a developer of technology; and making a meaningful contribution towards sustainable human development. The Masdar Institute is a private, not-for-profit, independent, research-driven institute developed with the support and cooperation of the Massachusetts Institute of Technology (MIT). The Institute offers Masters and (eventually) PhD programs in science and engineering disciplines, with a focus on advanced energy and sustainable technologies. It welcomes and encourages applications from qualified local and international students and provides fellowships to talented students who meet its high admission standards. Its faculty is of the highest quality and the intent is to have the structure of its top administration similar to MIT"s.
2010.04.13
View 10893
Photonic crystals allow the fabrication of miniaturized spectrometers
By Courtesy of Nanowerk Photonic crystals allow the fabrication of miniaturized spectrometers (Nanowerk Spotlight) Spectrometers are used in materials analysis by measuring the absorption of light by a surface or chemical substance. These instruments measure properties of light over a specific portion of the electromagnetic spectrum. In conventional spectrometers, a diffraction grating splits the light source into several beams with different propagation directions according to the wavelength of the light. Thus, to achieve sufficient spatial separation for intensity measurements at a small slit, a long light path – i.e., a large instrument – is required. However, for lab-on-a-chip or microTAS (total analysis system) applications, the spectrometer must be integrated into a sub-centimeter scale device to produce a stand-alone platform. To achieve this, researchers at the Korea Advanced Institute of Science and Technology (KAIST) propose a new paradigm in which the spectrometer is based on an array of photonic crystals with different bandgaps. "Because photonic crystals refelct light of different wavelengths selectively depending on their bandgaps, we can generate reflected light spanning the entire wavelength range for analysis at different spatial positions using patterned photonic crystals," Seung-Man Yang, Director of the National Creative Research Initiative Center for Intergrated Optofluidic Systems and Professor of the Department of Chemical & Biomolecular Engineering at KAIST, tells Nanowerk. "Therefore, when the light source impinges on the patterned photonic crytals, we can construct the spectrum using the reflection intensity profile from the constituent photonic crystals." Photonic crystals – also known as photonic band gap material – are similar to semiconductors, only that the electrons are replaced by photons (i.e. light). By creating periodic structures out of materials with contrast in their dielectric constants, it becomes possible to guide the flow of light through the photonic crystals in a way similar to how electrons are directed through doped regions of semiconductors. The photonic band gap (that forbids propagation of a certain frequency range of light) gives rise to distinct optical phenomena and enables one to control light with amazing facility and produce effects that are impossible with conventional optics. To demonstrate this new concept based on patterned photonic crystals, Yang and his group used non-close-packed colloidal crystals of silica particles dispersed in photocurable resin. Due to the repulsive interparticle potential, monodisperse silica particles spontaneously crystallize into non-close-packed face-centered cubic (fcc) structures at volume fractions above 0.1. Therefore, the particle volume fraction determines both the lattice constant and the bandgap position. a) Optical image of an ETPTA film containing porous photonic crystal stripe patterns with 20 different bandgaps. b) Reflectance spectra from the 20 strips. c) Optical microscope image of the middle region with the parallel stripe pattern (denoted as white-dotted box in a). d) Cross-sectional SEM images of first, sixth, eleventh and seventeenth strips. The scale bars in a, c and d are 1 cm, 2mm and 2 µm, respectively. (reprinted with permission from Wiley-VCH Verlag) Reporting their findings in a recent issue of Advanced Materials ("Integration of Colloidal Photonic Crystals toward Miniaturized Spectrometers"), the KAIST team has demonstrated the integration of colloidal photonic crystals with 20 different bandgaps into freestanding films (prepared by soft lithography), and their application as a spectrometer. Yang explains that the team was able to precisely control the photonic bandgap by varying the particle size and volume fration. "The prepared colloidal composite structures showed high physical rigidity and chemical resistivity" he says. "The composite structure is suitable for spectroscopic use due to the small full widths at half maximum (FWHMs) of the reflectance spectra, which mean that there is little overlap of the reflectance spectra of neighboring photonic crystal strips." "On the other hand" says Yang, "porous photonic crystals showed large FWHMs and high reflectivities, which should prove useful in many practical photonic applications that require high optical performance and physical rigidity as well as simple and inexpensive preparation." In addition to fabricating miniaturized spectrometers, which can for instance be integrated into small lab-on-a-chip devices, these integrated photonic crystals can be potentially used for tunable band reflection mirrors, optical switches, and tunable lasing cavities. Moreover, patterned photonic crystals with RGB colors are well-suited for use in reflection-mode microdisplay devices. Yang points out that, although the spectrometric resolution can be reduced by employing the smaller bandgap interval and photonic bandwidth, there is a limitation. "Now, we are studying photonic crystals with continuous modulation of bandgap position. We expect that the photonic crystals can reduce the resolution to 0.01 nm." By Michael Berger. Copyright 2010 Nanowerk
2010.03.17
View 11378
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