Yang
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The Hindu, "Use of microalgae helps in controlling pollution," December 8, 2011
The Hindu, an Indian newspaper, reported on December 8, 2011 a research work by Professor Ji-Won Yang from the Department of Chemical and Biomolecular Engineering. For the news article, please go to the link at http://www.thehindu.com/sci-tech/energy-and-environment/article2695634.ece?homepage=true.
The Hindu, December 8, 2011
Use of microalgae helps in controlling pollution
By N. Gopal Raj
2011.12.12 View 9075 -
Displaybank, KAIST Develops Flexible Display Metal Wiring Technology, May 27, 2011
On May 26, Korea Advanced Institute of Science (KAIST) announced that team of Prof. Yang from the Department of Mechanical Engineering developed flexible display metal wiring manufacturing-technology. For the article, please follow the link,
http://www.displaybank.com/eng/info/sread.php?id=5877
2011.05.31 View 8292
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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 13043
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KAIST Research Team Unveils Method to Fabricate Photonic Janus Balls
A research team led by Prof. Seung-Man Yang of the Department of Chemical and Biomolecular Engineering has found a method to fabricate photonic Janus balls with isotropic structural colors.
The finding draws attention since the newly-fabricated photonic balls may prove useful pigments for the realization of e-paper or flexible electronic displays.
The breakthrough was published in the Nov. 3 edition of the science journal "Advanced Materials." The Nov. 6 issue of "Nature" also featured it as one of the research highlights under the title of "Future Pixels."
Prof. Yang"s research team found that tiny marbles, black on one side and colored on the other, can be made by "curing" suspensions of silica particles with an ultraviolet lamp. When an electric field is applied, the marbles line up so that the black sides all face upwards, which suggests they may prove useful pigments for flexible electronic displays.
The researchers suspended a flow of carbon-black particles mixed with silica and a transparent or colored silica flow in a resin that polymerizes under ultraviolet light. They then passed the mixture through a tiny see-through tube. The light solidified the silica and resin as balls with differently colored regions, each about 200 micrometers in diameter.
Over the last decades, the development of industrial platforms to artificially fabricate structural color pigments has been a pressing issue in the research areas of materials science and optics. Prof. Yang, who is also the director of the National Creative Research Initiative Center for Integrated Optofluidic Systems, has led the researches focused on fabrication of functional nano-materials through the process of assembling nano-building blocks into designed patterns.
The "complementary hybridization of optical and fluidic devices for integrated optofluidic systems" research was supported by a grant from the Creative Research Initiative Program of the Ministry of Education, Science & Technology.
2008.11.12 View 12981 -
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 12119 -
Professor Yang Named Recipient of Dupont Science & Technology Award
Professor Yang Named Recipient of Dupont Science & Technology Award
- Named as the recipient of Dupont Science & Technology Award of 2007- In recognition of his development of optical?bio-functional photonic crystal structures through Self-assembly of nanoparticles
Seung-Man Yang, a professor of Chemical and Biomolecular Engineering of KAIST (President Nam Pyo Suh) and the president of the National Creative Research Initiatives Center for Photon and Fluid Integrated Circuit by the Ministry of Science and Technology, has been named as the recipient of Dupont Science & Technology Award.
Dupont Korea, associate of Dupont, a world-class science firm, has established and conferred ‘Dupont Science & Technology Award’ since 2002 to promote basic sciences and industrial development of Korea. Dupont Science & Technology Awards are awarded to scientists of universities or state-run institutes who have made outstanding R&D achievements in the fields of Chemistry, Chemical Engineering, Material Science and Material Engineering within five years. Dupont Korea announced on May 2, 2007 that Professor Yang is the recipient of the award this year, following the strict examination by the Koran Academy of Science and Technology (KAST).
The reason for the award is Professor Yang’s development of prototype optical?bio-functional photonic crystal structures that can process a huge amount of data, resulting from a study that has discovered the principle of Self-assembly where multifunctional nanoparticles are manufactured and assembled for themselves.
Professor Yang’s recent research result about photon structures and nano patterns was published by Nature (February 2, 2006 edition); posted on Heart-Cut, the portal site of the American Chemistry Society (ACS), as highlight paper two times (November 4, 2002 and May 1, 2006); and introduced at Research/Researcher of MRS Bulletin by the U.S. Material Research Society (MRS) as main paper in December 2003. Professor Yang is very famous in Korea and abroad for the excellences of his research achievements and has made request seminars at Harvard University, University of Wisconsin, Caltech, University of California, etc. He is also invited speaker and session organizer of the MRS and the SPIE.
2007.05.08 View 17082 -
A doctorate of Mechanical Engineering Named Recipient of Best Student Paper Award at International Society
Seung-Min Ryu, a doctorate of Mechanical Engineering under the supervision of Professor Dong-Yul Yang, has been named as a recipient of the best student paper award of the Society for Information Display (SID).
The title of the paper is ‘the study on the fabrication of super-high resolution cathode separators by X-ray lithography processes’. He proposed at this paper the fabrication of 12 micron-thick cathode separators, which can fabricate further delicate separators than the current 50 micron-thick commercial PDP separators, thereby significantly improving the resolution of PDPs in the future.
Ryu will make an oral presentation on this paper and win the award at the SID conference, which will take place in the U.S. for six days from May 20.
2007.04.23 View 14279 -
KAIST Chong-Moon Lee Library Opens
KAIST Chong-Moon Lee Library Opens
Jong-Moon Lee Library, management education library for scientists possessing the biggest amount of entrepreneurship data in Asia, opens in KAIST (President Nam-Pyo Suh) on Thursday, November 9, 2006.
Jong-Moon Lee Library was planned when Jong-Moon Lee, Chairman of AmBex, donated 2 million dollar to KAIST and founded Entrepreneurship Research Center at KAIST in 2004. Chairman Lee emphasized on the necessity of management education for scientists of advanced technology-based venture companies and set the management plan for Jong-Moon Lee Library securing the biggest amount of Entrepreneurship data in Asia.
Jong-Moon Lee Library possesses books for inspiring entrepreneurship, including ▲ books regarding how to prepare and evaluate business plans that support the realization of business ideas such as venture company founding, etc. ▲ administrative books necessary for company management such as leadership and finance, accounting, etc. ▲ economic books that foster reader’s insight over economy and society. The number of books is about 4,900 and various journals including Harvard Business Review are also provided.
KAIST Entrepreneurship Research Center (President Tae-Yong Yang) is now carrying out ▲ the management of entrepreneurship library for Engineering students and businessmen ▲ programs for entrepreneurship education and venture-company founding ▲aid for business plan forums and academic conferences. It benchmarks Stanford Technology Venture Program (STVP) of Stanford University, which is evaluated the most excellent program in researches and realization of entrepreneurship, and manages education programs for scientific manpower with international managing minds on the basis of world’s best capabilities in scientific researches and education of KAIST.
President Yang explained about the management plan by saying, “Following Chairman Jong-Moon Lee’s intention, the center will educate entrepreneurship to engineering students and properly diagnose initial values of excellent technologies, thereby making venture companies flourish.”
2006.11.16 View 14579
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Professor Yang Receives Academic Award
By Ki-beom Lee / Reporter
The KAIST Herald December 3, 2003
The Professor Dong-yol Yang of the Department of Mechanical Engineering received the Sang-woo Academic Award last month. Unlike other awards of similar nature, this award is given to one of many leading scientists who has written six to seven papers in the previous year. This award is special in that Professor Yang retired as chairman of the Korean Society for Technology of Plasticity in December 2002. Professor Yang received a prize on the research of the anisotropic pressing out process. He has also written papers based on the twenty-five years of research at Korea Advanced Institute of Science and Technology and has researched high-speed modeling for the first time in Korea.
2004.03.15 View 15764