Rough
-
Nature Photonics, a peer-reviewed scientific journal, released a paper written by a KAIST research team on the time-of-flight measurement.
Professor Seung-Woo Kim of the Mechanical Engineering Department, KAIST, and his research team published the result of their study on the measurement of 1 nanometer (nm) precision.
“The time-of-flight of light pulses has long been used as a direct measure of distance, but state-of-the-art measurement precision using conventional light pulses or microwaves peaks at only several hundreds of micrometers. Here, we improve the time-of-flight precision to the nanometer regime by timing femtosecond pulses through phase-locking control of the pulse repetition rate using the optical cross-correlation technique,” Professor Kim said.
According to the experiment conducted by the research team, “An Allan deviation of 117 nm in measuring a 700m distance in air at a sampling rate of 5 millisecond (ms) once the pulse repetition is phased-locked, which reduces to 7 nm as the averaging time increases to 1 second (s).”
When measuring an object located in a far distance, a laser beam is projected to the object, and the reflected light is analyzed; the light is then converted into an electric signal to calculate the distance. In so doing, Professor Kim said, the conventional method of measurement creates at least 1 mm of deviation.
He argues, “This enhanced capability is maintained at long range without periodic ambiguity, and is well suited to lidar applications. This method could also be applied to future space missions involving formation-flying satellites for synthetic aperture imaging and remote experiments related to general relativity theory."
Nature Photonics published the article online on August 8, 2010.
2010.08.18 View 13263 -
Native-like Spider Silk Produced in Metabolically Engineered Bacterium
Microscopic picture of 285 kilodalton recombinant spider silk fiber
Researchers have long envied spiders’ ability to manufacture silk that is light-weighted while as strong and tough as steel or Kevlar. Indeed, finer than human hair, five times stronger by weight than steel, and three times tougher than the top quality man-made fiber Kevlar, spider dragline silk is an ideal material for numerous applications. Suggested industrial applications have ranged from parachute cords and protective clothing to composite materials in aircrafts. Also, many biomedical applications are envisioned due to its biocompatibility and biodegradability.
Unfortunately, natural dragline silk cannot be conveniently obtained by farming spiders because they are highly territorial and aggressive. To develop a more sustainable process, can scientists mass-produce artificial silk while maintaining the amazing properties of native silk? That is something Sang Yup Lee at the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, the Republic of Korea, and his collaborators, Professor Young Hwan Park at Seoul National University and Professor David Kaplan at Tufts University, wanted to figure out. Their method is very similar to what spiders essentially do: first, expression of recombinant silk proteins; second, making the soluble silk proteins into water-insoluble fibers through spinning.
For the successful expression of high molecular weight spider silk protein, Professor Lee and his colleagues pieced together the silk gene from chemically synthesized oligonucleotides, and then inserted it into the expression host (in this case, an industrially safe bacterium Escherichia coli which is normally found in our gut). Initially, the bacterium refused to the challenging task of producing high molecular weight spider silk protein due to the unique characteristics of the protein, such as extremely large size, repetitive nature of the protein structure, and biased abundance of a particular amino acid glycine. “To make E. coli synthesize this ultra high molecular weight (as big as 285 kilodalton) spider silk protein having highly repetitive amino acid sequence, we helped E. coli overcome the difficulties by systems metabolic engineering,” says Sang Yup Lee, Distinguished Professor of KAIST, who led this project. His team boosted the pool of glycyl-tRNA, the major building block of spider silk protein synthesis. “We could obtain appreciable expression of the 285 kilodalton spider silk protein, which is the largest recombinant silk protein ever produced in E. coli. That was really incredible.” says Dr. Xia.
But this was only step one. The KAIST team performed high-cell-density cultures for mass production of the recombinant spider silk protein. Then, the team developed a simple, easy to scale-up purification process for the recombinant spider silk protein. The purified spider silk protein could be spun into beautiful silk fiber. To study the mechanical properties of the artificial spider silk, the researchers determined tenacity, elongation, and Young’s modulus, the three critical mechanical parameters that represent a fiber’s strength, extensibility, and stiffness. Importantly, the artificial fiber displayed the tenacity, elongation, and Young’s modulus of 508 MPa, 15%, and 21 GPa, respectively, which are comparable to those of the native spider silk.
“We have offered an overall platform for mass production of native-like spider dragline silk. This platform would enable us to have broader industrial and biomedical applications for spider silk. Moreover, many other silk-like biomaterials such as elastin, collagen, byssus, resilin, and other repetitive proteins have similar features to spider silk protein. Thus, our platform should also be useful for their efficient bio-based production and applications,” concludes Professor Lee.
This work is published on July 26 in the Proceedings of the National Academy of Sciences (PNAS) online.
2010.07.28 View 19566 -
Professor Eun-Seong Kim and his research staff observed the phenomena of hysteresis and relaxation dynamics from supersolid Helium
Professor Eun-Seong Kim and his research staff observed the phenomena of hysteresis and relaxation dynamics from supersolid Helium.
Their research paper was published in Nature Physics for the issue of April 2010.
If we take Helium 4 and cool it down at temperatures below 2.176 Kelivin, liquid helium 4 undergoes a phase transition and becomes superfluid with a zero viscosity. The superfluidity was observed in solid helium through an experiment performed by researchers of Pennsylvania State University in 2004. One of the researchers then was Professor Eun-Seong Kim in the Department of Physics, KAIST.
Professor Kim and his research staff, Hyung-Soon Choi, Ph.D., recently published their research results in Nature Physics (April 2010), a highly esteemed journal in the field, on the phenomena of hysteresis and relaxation dynamics observed in supersolid Helium.
For the paper, please download the attached .pdf file.
Nature Physics link: http://www.nature.com
2010.04.13 View 13659 -
Prof. Lee"s Team Succeeds in Producing Plastics Without Use of Fossil Fuels
A team of scientists led by Prof. Sang-Yup Lee of the Department of Biological Sciences at KAIST have succeeded in producing the polymers used for everyday plastics through bioengineering, rather than through the use of fossil fuel based chemicals, the university authorities said on Tuesday (Nov. 24).
This groundbreaking research, which may now allow for the production of environmentally conscious plastics, has been published in two papers in the journal Biotechnology and Bioengineering.
Polymers are molecules found in everyday life in the form of plastics and rubbers. The team consisted of scientists from KAIST and Korean chemical company LG Chem focused their research on polylactic acid (PLA), a bio-based polymer which holds the key to producing plastics through natural and renewable resources.
"The polyesters and other polymers we use everyday are mostly derived from fossil oils made through the refinery or chemical process," said Lee. "The idea of producing polymers from renewable biomass has attracted much attention due to the increasing concerns of environmental problems and the limited nature of fossil resources. PLA is considered a good alternative to petroleum based plastics as it is both biodegradable and has a low toxicity to humans."
Until now PLA has been produced in a two-step fermentation and chemical process of polymerization, which is both complex and expensive. Now, through the use of a metabolically engineered strain of E.coli, the team has developed a one-stage process which produces polylactic acid and its copolymers through direct fermentation. This makes the renewable production of PLA and lactate-containing copolymers cheaper and more commercially viable.
"By developing a strategy which combines metabolic engineering and enzyme engineering, we"ve developed an efficient bio-based one-step production process for PLA and its copolymers," said Lee. "This means that a developed E. coli strain is now capable of efficiently producing unnatural polymers, through a one-step fermentation process,"
This combined approach of systems-level metabolic engineering and enzyme engineering now allows for the production of polymer and polyester based products through direct microbial fermentation of renewable resources.
"Global warming and other environmental problems are urging us to develop sustainable processes based on renewable resources," concluded Lee. "This new strategy should be generally useful for developing other engineered organisms capable of producing various unnatural polymers by direct fermentation from renewable resources".
2009.11.30 View 15866 -
Int'l Telematic Music Concert for Peace to Take Place on Nov. 20
Renowned musicians in five international locations perform new contemporary music works for peace through a real-time performance on the internet. Local audiences in Seoul, Banff, New York, San Diego and Belfast will also have a chance to hear a program.
In Seoul, the "International Telematic Music Concert for Peace" will be held at the LeeHaeRang Art Theater, Dongguk University, in Seoul on Nov. 20 at 9:30 a.m., under the presentation of KAIST"s Graduate School of Culture Technology and MARTE Lab, Dongguk University. Telematic music is real-time performance via the internet by musicians in different geographic locations.
The program of the concert includes "Hope"s Dream" by Mark Dresser and Sarah Weaver; "Disparate Bodies" by Pedro Rebelo, "Rock, Paper, Scissors" by Chris Chafe. The Korean act to be performed is "Green-colored Harmony" by Jun Kim.
In addition to the two Korean universities, the World Association of Former United Nations Internes and Fellows (WAFUNIF), University of California San Diego, the Banff Center of Canada and Queen"s University in Belfast are participating in the project.
The performance will take place on high-bandwidth internet with JackTrip audio software developed by Chris Chafe and Access Grid video software developed at Argonne National Laboratory.
"Connecting the five different cities together through super-speed Internet network and transmitting sound and images in real time is challenging technically. But, we also expect that more exciting results will be created in the course of transforming the sound into visual images," said Woon-Seung Yeo, a professor of the Graduate School of Culture Technology, who was responsible for visuals in the project.
2009.11.19 View 15027 -
Board Chairman Chung Makes First Visit to Building Named After Him
Moon-Soul Chung, chairman of the KAIST board of trustees, visited the building built with his donation on Monday (Oct. 19) for the first time since he made the deed of gift eight years ago, university authorities said on Monday (Oct. 19).
In 2000, Chung, founder and former CEO of Mirae Corp, manufacturer of semiconductor testing equipment, announced retirement and handed over the presidency of his company to one of his managing directors. One year later in 2001, he donated 30 billion won, then equivalent to $30 million, to KAIST. It was by then the largest amount given by a single donor.
The major part of his donation went to constructing a building for the newly-established Department of Bio and Brain Engineering, and it was named after him. However, Chung did not attend the ground-breaking and dedication ceremonies, saying that he would not enter the building until KAIST achieved a breakthrough technology which can inject a hope to Koreans.
On his first visit to the building, he was briefed on the major research outcomes of the department over the past seven years, which were highlighted by the recent invention of an apparatus for measuring perfusion rate of legs. A KAIST team headed by Prof. Chul-Hee Choi invented a light leakage prevention unit including a light emitting device for radiating light having a certain wavelength onto a living body injected with Indocyanine Green (ICG).
According to Prof. Choi, the invention relates to an apparatus for measuring the perfusion rate of legs. The invention also includes a light leakage prevention housing formed to prevent transmission of external light.
Chung expressing satisfaction with the achievements and encouraged professors, researchers and students working at the Moon-Soul Chung Building.
2009.10.20 View 15167 -
KAIST Undergraduates Open Four-Day International Conference
The ICISTS-KAIST, an annual international conference organized by KAIST undergraduate students, opened on Thursday (Aug. 20) at the KAIST"s main campus in Daejeon.
The 2009 ICISTS (International Conference for the Integration of Science and Technology into Society) drew around 200 experts and students from 44 countries. Since its inception in 2005 to promote discourse on important science and technology issues affecting modern society, the conference has served as an opportunity for academic networking among students in various parts of the world.
The four-day conference consists of lectures, open discussions among lecturers and students, field trips to help students to understand actual applications, and team projects.
This year"s conference offers three workshops under the themes of "Climate Change: Merging Technology and Policy for Green Solutions"; "Human-Computer Interaction: Designing Computer System for Intuitive Human Access"; and "Nano Clinic: Breakthrough in Conquering Disease."
Lectures by invited experts in various scientific fields will help broaden students" perspectives particularly from interdisciplinary viewpoints, said an organizer of the conference.
2009.08.28 View 16439 -
KAIST's OLEV Best Model of Creative Growth Engine
Various models of electric vehicles designed to replace the internal combustion automobiles face significant problems as they invariably failed to overcome the limitations involving lithium battery in terms of power capacity, weight, raw materal price, recharging time and preparation of charging stations. Worst of all, the limited supply of lithium will eventually raise its price sky high when all cars use lithium batteries, and the economic value of electric cars will be lost.
KAIST"s online electric vehicle project (OLEV) seeks to resolve these fundamental problems involving electric vehicles that have so far been developed. KAIST OLEV, a project to develop a new growth engine for the nation and lead the future of global automotive industry, is an entirely new concept: the electric vehicle picks up power from underground power supplier lines through the non-contact magnetic charging method, while either running or standing. This is the first eco-friendly and economic automotive system that can resolve the problems inherent to previously-developed electric vehicles, according to the KAIST OLEV Project Center.
In February 2009, KAIST researchers first proved that up to 80 percent power conveyance is possible through a gap of 1 centimeter from the power line, and in July they successfully supplied power to a bus -- up to 60 percent across a 12 cm gap from the power line embedded in the ground -- using power supply and pick-up devices they developed. In this process, KAIST has secured the core technologies for maximizing power efficiency and minimizing the cost of installing the non-contact power supply system. KAIST has established the Online Electric Vehicle Co., Ltd., to undertake business activities related to the OLEV project, including the IPR on power supply and pick-up devices, parts and accessories and commercial promotion. A demonstration event is scheduled for Aug. 13, Thursday.
The impact of the development of the OLEV technology on the energy and environment issues and the overall economy will be enormous. In case a half of the total automobiles running in Korea, or 6 million vehicles, are replaced with OLEV, electric power produced by just two of the nation"s atomic power plants will be enough to operate them all, and the nation will be able to reduce crude oil import by 35 million barrels worth U.S.$3 billion a year (supposing $80 per barrel).
Korea"s export of OLEV units will in the future surpass the present level of overseas sale of conventional cars. When nations use online electric vehicles in large numbers, their demand for CO2-free power plants will grow. Korea has cutting-edge technology in the construction of atomic power plants. As a world leader in the area of nuclear power plant, Korea will enjoy new opportunities to contribute to the global advancement of atomic power generation as well as transportation industries.
Korea still shares a small portion of the world"s automobile market estimated to worth some 2,000 trillion Korean won. But commercialization of the OLEV technology worldwide will greatly enhance Korea"s global automotive market share. Successful development of the online electric vehicle requires preemptive investment and positive support by the government for the ultimate purpose of resolving energy and environment problems.
If and when domestic enterprises secure technological supremacy in the next generation automobile market with their online electric vehicles which will replace the 100-year-old combustion engine, it will be the most desirable shortcut to raising Korea"s international competitiveness. OLEV promises to be the model of creative growth engine in the 21st century.
2009.07.30 View 18078
-
KAIST President Suh Honored with 2009 ASME Medal
KAIST President Nam-Pyo Suh has chosen as the 2009 winner of the ASME Medal presented by the American Society of Mechanical Engineers, university authorities said on Thursday (July 2).
President Suh received the honor for "seminal contributions to the advancement of engineering through research in tribology, polymer processing, metal processing, design and manufacturing, as well as contributions to engineering education and research infrastructure."
The selection of President Suh was unanimously approved by the 13-member Board of Governors of the ASME. Suh became the first scientist of Asian descent in the award"s 89-year-long history.
Founded in 1880, the ASME is a non-profit professional organization promoting the art, science and practice of mechanical and multidisciplinary engineering and allied sciences. The organization is known for setting codes and standards for mechanical devices. As of 2009, it has 120,000 members worldwide.
Only one ASME medal is awarded annually to recognize "eminently distinguished achievement." The award consists of a $17,000 honorarium, a gold medal, certificate and travel supplement for two days. It will be presented to President Suh during the 2009 International Mechanical Engineering Congress and Exposition, which will be held in Lake Buena Vista, Florida, November 13-10, 2009.
President Suh is an internationally known educator, engineer and inventor. Born in Korea, he immigrated to the U.S. in 1954 to join his father, who was teaching at Harvard. He earned both his bachelor"s and master"s degrees from MIT before coming to Carnegie Tech for his doctoral education in mechanical engineering.
While teaching at MIT, he founded the MIT-Industry Polymer Processing Program in 1973 and the Laboratory for Manufacturing and Productivity. He left these positions in 1984 to serve with the U.S. National Science Foundation as its assistant director for engineering, until 1988.
He invented many new materials, products and manufacturing processes, earning more than 60 U. S. patents and founding several companies. He has written seven books and more than 300 scholarly papers. Among dozens of honors throughout his career, President Suh most recently received the 2007 Lifetime Achievement from the Society of Plastics Engineers.
The ASME conducts one of the world"s largest technical publishing operations through its ASME Press, holds numerous technical conferences and hundreds of professional development courses each year, and sponsors numerous outreach and educational programs.
2009.07.02 View 14757