본문 바로가기
대메뉴 바로가기
KAIST
Newsletter Vol.25
Receive KAIST news by email!
View
Subscribe
Close
Type your e-mail address here.
Subscribe
Close
KAIST
NEWS
유틸열기
홈페이지 통합검색
-
검색
KOREAN
메뉴 열기
by recently order
by view order
Professor Rim Presents at IAEA Workshop in Vienna
Professor Chun-Taek Rim of the Department of Nuclear and Quantum Engineering at KAIST recently attended the International Atomic Energy Agency (IAEA)’s workshop on the Application of Wireless Technologies in Nuclear Power Plant Instrumentation and Control System. It took place on March 30-April 2, 2015, in Vienna, Austria. Representing Korea, Professor Rim gave a talk entitled “Highly Reliable Wireless Power and Communications under Severe Accident of Nuclear Power Plants (NPPs).” About 20 industry experts from 12 countries such as AREVA (France), Westinghouse (US), Oak Ridge National Laboratory (US), Hitachi (Japan), and ENEA (Italy) joined the meeting. The IAEA hosted the workshop to explore the application of wireless technology for the operation and management of NPPs. It formed a committee consisting of eminent professionals worldwide in NPP instrumentation and control systems, communications, and nuclear power to examine this issue in-depth and to conduct various research projects for the next three years. In particular, the committee will concentrate its research on improving the reliability and safety of using wireless technology, not only in the normal operation of nuclear plants but also in extreme conditions such as the Fukushima Daiichi nuclear accident. The complementation, economic feasibility, and standardization of NPPs when applying wireless technology will be also discussed. Professor Rim currently leads the Nuclear Power Electronics and Robotics Lab at KAIST (http://tesla.kaist.ac.kr/index_eng.php?lag=eng). Picture 1: Professors Rim presents his topic at the IAEA Workshop in Vienna. Picture 2: The IAEA Workshop Participants
2015.04.07
View 11372
Novel Photolithographic Technology Enabling 3D Control over Functional Shapes of Microstructures
Professor Shin-Hyun Kim and his research team in the Department of Chemical and Biomolecular Engineering at KAIST have developed a novel photolithographic technology enabling control over the functional shapes of micropatterns using oxygen diffusion. The research was published online in the March 13th issue of Nature Communications and was selected as a featured image for the journal. Photolithography is a standard optical process for transferring micropatterns on to a substrate by exposing specific regions of the photoresist layer to ultraviolet (UV) light. It is used widely throughout industries that require micropatterns, especially in the semiconductor manufacturing industry. Conventional photolithography relied on photomasks which protected certain regions of the substrate from the input UV light. Areas covered by the photomasks remain intact with the base layer while the areas exposed to the UV light are washed away, thus creating a micropattern. This technology was limited to a two-dimensional, disc-shaped design as the boundaries between the exposed and roofed regions are always in a parallel arrangement with the direction of the light. Professor Kim’s research team discovered that: 1) the areas exposed to UV light lowered the concentration of oxygen and thus resulted in oxygen diffusion; and 2) manipulation of the diffusion speed and direction allowed control of the growth, shape and size of the polymers. Based on these findings, the team developed a new photolithographic technology that enabled the production of micropatterns with three-dimensional structures in various shapes and sizes. Oxygen was considered an inhibitor during photopolymerization. Photoresist under UV light creates radicals which initialize a chemical reaction. These radicals are eliminated with the presence of oxygen and thus prevents the reaction. This suggests that the photoresist must be exposed to UV light for an extended time to completely remove oxygen for a chemical reaction to begin. The research team, however, exploited the presence of oxygen. While the region affected by the UV light lowered oxygen concentration, the concentration in the untouched region remained unchanged. This difference in the concentrations caused a diffusion of oxygen to the region under UV light. When the speed of the oxygen flow is slow, the diffusion occurs in parallel with the direction of the UV light. When fast, the diffusion process develops horizontally, outward from the area affected by the UV light. Professor Kim and his team proved this phenomenon both empirically and theoretically. Furthermore, by injecting an external oxygen source, the team was able to manipulate diffusion strength and direction, and thus control the shape and size of the polymer. The use of the polymerization inhibitors enabled and facilitated the fabrication of complex, three-dimensional micropatterns. Professor Kim said, “While 3D printing is considered an innovative manufacturing technology, it cannot be used for mass-production of microscopic products. The new photolithographic technology will have a broad impact on both the academia and industry especially because existing, conventional photolithographic equipment can be used for the development of more complex micropatterns.” His newest technology will enhance the manufacturing process of three-dimensional polymers which were considered difficult to be commercialized. The research was also dedicated to the late Professor Seung-Man Yang of the Department of Chemical and Biomolecular Engineering at KAIST. He was considered one of the greatest scholars in Korea in the field of hydrodynamics and colloids. Picture 1: Featured Image of Nature Communications, March 2015 Picture 2: Polymers with various shapes and sizes produced with the new photolithographic technology developed by Professor Kim
2015.04.06
View 9738
Polymers with Highly Improved Light-transformation Efficiency
A joint Korean research team, led by Professor Bum-Joon Kim of the Department of Chemical and Biomolecular Engineering at KAIST and Professor Young-Woo Han of the Department of Nanofusion Engineering at Pusan National University, has developed a new type of electrically-conductive polymer for solar batteries with an improved light-transformation efficiency of up to 5%. The team considers it a viable replacement for existing plastic batteries for solar power which is viewed as the energy source of the future. Polymer solar cells have greater structural stability and heat resistance compared to fullerene organic solar cells. However, they have lower light-transformation efficiency—below 4%—compared to 10% of the latter. The low efficiency is due to the failure of blending among the polymers that compose the active layer of the cell. This phenomenon deters the formation and movement of electrons and thus lowers light-transformation efficiency. By manipulating the structure and concentration of conductive polymers, the team was able to effectively increase the polymer blending and increase light-transformation efficiency. The team was able to maximize the efficiency up to 6% which is the highest reported ratio. Professor Kim said, “This research demonstrates that conductive polymer plastics can be used widely for solar cells and batteries for mobile devices.” The research findings were published in the February 18th issue of the Journal of the American Chemical Society (JACS). Picture: Flexible Solar Cell Polymer Developed by the Research Team
2015.04.05
View 9955
ITTP Produces 119 Graduates from 52 Countries.
“Transparency of Costa Rica was highly improved after adopting an electronic purchase and supply system from Korea.” So noted a public official from the technical office of the digital government in Costa Rica, Ileana Palaco, who entered the master’s program in KAIST’s Global Information and Telecommunication Technology Program (ITTP) last September. She also said, “The electronic government of Korea is an exemplary model emulated in the establishment of the e-Government system in Central and South America. I am eager to introduce Korean IT technology and policies to the countries in the region.” Consisting of master’s and doctoral programs designed for public officials and technical experts in emerging countries, ITTP fosters international cooperation, builds human networks, and supports domestic companies in technology transfers. For the past twenty years, the IT industry has been the key to Korea’s development. Utilizing its advancement in the IT technology, Korea provides developing countries with the support necessary for their continuous growth in the 21st century. To that end, KAIST created ITTP which invites government officials from emerging countries with a growing IT industry. Run by the Business and Technology Management Department of KAIST since 2006, ITTP has produced 119 graduates from 52 countries. For the past 10 years, 57 students from Africa, 45 from South East-Asia, 16 from Eastern Europe, and 7 from the Middle East were accepted to the program. The program consists of theory-based classes which introduces the technology and IT policies of Korea and project-based classes for university-industry cooperation. In the latter, experts from professional organizations in IT such as the Electronics and Telecommunications Research Institute (ETRI), the National Information Society Agency (NIA), and Korea Telecom participate and provide information based on industry experience. Foreign governments and international organizations have reacted positively to this program. Having recognized its excellence, the International Telecommunication Union (ITU) has supported it by sending the application information to 193 member countries. The African Development Bank (AFDB) chose ITTP as one of the Next Generation African Leadership Programs and assigned 19 public officials from Africa. ITTP graduates have played a large role in promoting the e-Government system overseas. In In 25 cases in 2012, graduates participated as researchers in 6 cases. Thanks to the support of elite public officials from emerging countries who graduated from ITTP, Korean technology companies can bring their technology to overseas countries more effectively. Recently, government officials from these countries have been asking for both long and short- term programs on technology and IT policies. In response, KAIST is planning to expand the program. Professor Jaejeung Rho from the Business and Technology Management Department who supervises this program said, “Allowing public officials in the field of IT all over the world to know more about Korea is very important in raising Korea’s reputation in technology and in the globe” and added that “having these officials is a boon in keeping our country’s competitive edge in the IT industry.” Picture: About 60 people including ITTP students, the Nigerian ambassador to Korea, and President Steve Kang of KAIST joined a ceremony to raise a scholarship fund for KAIST on April 2, 2015 at Munji campus in Daejeon.
2015.04.03
View 7701
Professor Shim Featured with His Drone System in IEEE Spectrum
The IEEE Spectrum, a technology and science magazine published by the Institute of Electrical and Electronics Engineers (IEEE), featured an article of KAIST’s autonomous unmanned aerial vehicles (UAVs) entitled “South Korea Prepares for Drone vs. Drone Combat,” posted on April 1, 2015. The article introduces the anti-drone defense system being developed by Professor “David” Hyunchul Shim of the Department of Aerospace Engineering at KAIST. With the goal of developing guard drones that can detect and capture unknown UAVs, the anti-drone defense system consists of reconnaissance drones, agile multi-rotor UAVs equipped with nets which are dropped to snare enemy drones, and transport UAVs to carry smaller drones. Professor Shim currently leads KAIST’s Unmanned System Research Group (USRG, http://unmanned.kaist.ac.kr/) and Center of Field Robotics for Innovation, Exploration, aNd Defense (C-FRIEND). For the article, please go to http://spectrum.ieee.org/automaton/robotics/aerial-robots/south-korea-drone-vs-drone.
2015.04.02
View 11512
Mystery in Membrane Traffic How NSF Disassembles Single SNAR Complex Solved
KAIST researchers discovered that the protein N-ethylmaleimide-sensitive factor (NSF) unravels a single SNARE complex using one round ATP turnover by tearing the complex with a single burst, contradicting a previous theory that it unwinds in a processive manner. In 2013, James E. Rothman, Randy W. Schekman, and Thomas C. Südhof won the Nobel Prize in Physiology or Medicine for their discoveries of molecular machineries for vesicle trafficking, a major transport system in cells for maintaining cellular processes. Vesicle traffic acts as a kind of “home-delivery service” in cells. Vesicles package and deliver materials such as proteins and hormones from one cell organelle to another. Then it releases its contents by fusing with the target organelle’s membrane. One example of vesicle traffic is in neuronal communications, where neurotransmitters are released from a neuron. Some of the key proteins for vesicle traffic discovered by the Nobel Prize winners were N-ethylmaleimide-sensitive factor (NSF), alpha-soluble NSF attachment protein (α-SNAP), and soluble SNAP receptors (SNAREs). SNARE proteins are known as the minimal machinery for membrane fusion. To induce membrane fusion, the proteins combine to form a SNARE complex in a four helical bundle, and NSF and α-SNAP disassemble the SNARE complex for reuse. In particular, NSF can bind an energy source molecule, adenosine triphosphate (ATP), and the ATP-bound NSF develops internal tension via cleavage of ATP. This process is used to exert great force on SNARE complexes, eventually pulling them apart. However, although about 30 years have passed since the Nobel Prize winners’ discovery, how NSF/α-SNAP disassembled the SNARE complex remained a mystery to scientists due to a lack in methodology. In a recent issue of Science, published on March 27, 2015, a research team, led by Tae-Young Yoon of the Department of Physics at the Korea Advanced Institute of Science and Technology (KAIST) and Reinhard Jahn of the Department of Neurobiology of the Max-Planck-Institute for Biophysical Chemistry, reports that NSF/α-SNAP disassemble a single SNARE complex using various single-molecule biophysical methods that allow them to monitor and manipulate individual protein complexes. “We have learned that NSF releases energy in a burst within 20 milliseconds to “tear” the SNARE complex apart in a one-step global unfolding reaction, which is immediately followed by the release of SNARE proteins,” said Yoon. Previously, it was believed that NSF disassembled a SNARE complex by unwinding it in a processive manner. Also, largely unexplained was how many cycles of ATP hydrolysis were required and how these cycles were connected to the disassembly of the SNARE complex. Yoon added, “From our research, we found that NSF requires hydrolysis of ATPs that were already bound before it attached to the SNAREs—which means that only one round of an ATP turnover is sufficient for SNARE complex disassembly. Moreover, this is possible because NSF pulls a SNARE complex apart by building up the energy from individual ATPs and releasing it at once, yielding a “spring-loaded” mechanism.” NSF is a member of the ATPases associated with various cellular activities family (AAA+ ATPase), which is essential for many cellular functions such as DNA replication and protein degradation, membrane fusion, microtubule severing, peroxisome biogenesis, signal transduction, and the regulation of gene expression. This research has added valuable new insights and hints for studying AAA+ ATPase proteins, which are crucial for various living beings. The title of the research paper is “Spring-loaded unraveling of a single SNARE complex by NSF in one round of ATP turnover.” (DOI: 10.1126/science.aaa5267) Youtube Link: https://www.youtube.com/watch?v=FqTSYHtyHWE&feature=youtu.be Picture 1. Working model of how NSF/α-SNAP disassemble a single SNARE complex Picture 2. After neurotransmitter release, NSF disassembles a single SNARE complex using a single round of ATP turnover in a single burst reaction.
2015.03.28
View 10013
KAIST & the Classic 500 Co Sign for Mobile Healthcare Research
KAIST and The Classic 500 Co., Ltd., an elder care provider based in Seoul, signed a memorandum of understanding to expand medical services by cooperating on the research of medical services and IT on March 24, 2015. Twenty people from the two institutions, including President Steve Kang, Dong-Hyun Bak, CEO of The Classic 500 and Mun-Sul Jeong, a former KAIST Chairman of the Board, attended the signing ceremony. Under the agreement, the two institutions will cooperate on mobile healthcare research and the development of a telemedicine system. They will also research and develop a system to better serve society with medical services. The Classic 500, established by Konkuk University in Korea, provides nursing care services and assisted living facilities for senior citizens.
2015.03.26
View 7955
Mutations Occurring Only in Brain Responsible for Intractable Epilepsy Identified
KAIST researchers have discovered that brain somatic mutations in MTOR gene induce intractable epilepsy and suggest a precision medicine to treat epileptic seizures. Epilepsy is a brain disorder which afflicts more than 50 million people worldwide. Many epilepsy patients can control their symptoms through medication, but about 30% suffer from intractable epilepsy and are unable to manage the disease with drugs. Intractable epilepsy causes multiple seizures, permanent mental, physical, and developmental disabilities, and even death. Therefore, surgical removal of the affected area from the brain has been practiced as a treatment for patients with medically refractory seizures, but this too fails to provide a complete solution because only 60% of the patients who undergo surgery are rendered free of seizures. A Korean research team led by Professor Jeong Ho Lee of the Graduate School of Medical Science and Engineering at the Korea Advanced Institute of Science and Technology (KAIST) and Professor Dong-Seok Kim of Epilepsy Research Center at Yonsei University College of Medicine has recently identified brain somatic mutations in the gene of mechanistic target of rapamycin (MTOR) as the cause of focal cortical dysplasia type II (FCDII), one of the most important and common inducers to intractable epilepsy, particularly in children. They propose a targeted therapy to lessen epileptic seizures by suppressing the activation of mTOR kinase, a signaling protein in the brain. Their research results were published online in Nature Medicine on March 23, 2015. FCDII contributes to the abnormal developments of the cerebral cortex, ranging from cortical disruption to severe forms of cortical dyslamination, balloon cells, and dysplastic neurons. The research team studied 77 FCDII patients with intractable epilepsy who had received a surgery to remove the affected regions from the brain. The researchers used various deep sequencing technologies to conduct comparative DNA analysis of the samples obtained from the patients’ brain and blood, or saliva. They reported that about 16% of the studied patients had somatic mutations in their brain. Such mutations, however, did not take place in their blood or saliva DNA. Professor Jeong Ho Lee of KAIST said, “This is an important finding. Unlike our previous belief that genetic mutations causing intractable epilepsy exist anywhere in the human body including blood, specific gene mutations incurred only in the brain can lead to intractable epilepsy. From our animal models, we could see how a small fraction of mutations carrying neurons in the brain could affect its entire function.” The research team recapitulated the pathogenesis of intractable epilepsy by inducing the focal cortical expression of mutated mTOR in the mouse brain via electroporation method and observed as the mouse develop epileptic symptoms. They then treated these mice with the drug called “rapamycin” to inhibit the activity of mTOR protein and observed that it suppressed the development of epileptic seizures with cytomegalic neurons. “Our study offers the first evidence that brain-somatic activating mutations in MTOR cause FCDII and identifies mTOR as a treatment target for intractable epilepsy,” said co-author Dr. Dong-Seok Kim, a neurosurgeon at Yonsei Medical Center with the country’s largest surgical experiences in treating patients with this condition. The research paper is titled “Brain somatic mutations in MTOR cause focal cortical dysplasia type II leading to intractable epilepsy.” (Digital Object Identifier #: 10.1038/nm.3824) Picture 1: A schematic image to show how to detect brain specific mutation using next-generation sequencing technology with blood-brain paired sample. Simple comparison of non-overlapping mutations between affected and unaffected tissues is able to detect brain specific mutations. Picture 2: A schematic image to show how to generate focal cortical dysplasia mouse model. This mouse model open the new window of drug screening for seizure patients. Picture 3: Targeted medicine can rescue the focal cortical dysplasia symptoms including cytomegalic neuron & intractable epilepsy.
2015.03.25
View 13311
KAIST Clinic's Dr. Joo-yeon Kim Receives Minister's Award
Dr. Joo-yeon Kim receives citation on “The Fifth Tuberculosis Prevention Day” for her contribution to campus tuberculosis outbreak prevention. Dr. Joo-Yeon Kim, the general manager of medical services of KAIST Clinic, received an award from the Korean Ministry of Health and Welfare on March 24, 2015. The award ceremony took place during “The Fifth Tuberculosis Prevention Day,” hosted by the Ministry of Health and Welfare and supervised by the Korea Centers for Disease Control and Prevention. The event was held at Seoul Sejong Cultural Center with 300 distinguished guests in attendance including the Minister of Health and Welfare, the Committee Members of the National Assembly Health and Welfare Committee, and the Director of Korea Centers for Disease Control Prevention. The award acknowledges Dr. Kim’s contribution to curbing a tuberculosis (TB) outbreak on KAIST’s campus in 2013. In cooperation with the Infectious Disease Prevention Committee in KAIST, Korea Centers for Disease Control and Prevention, and Yuseong Public Health Centre, Dr. Kim’s swift treatment and rigorous control of both TB and latent TB patients prevented further outbreaks. The KAIST Clinic is the first university-affiliated clinic established in September 2010 after Neil Pappalardo, the President of MEDITEC in the US, donated $2.5 million to KAIST. It is currently running 10 medical departments including those in family medicine, stress clinic, and dentistry to provide medical care to students and staff. Every March 24 marks the annual “Tuberculosis Prevention Day” and “World Tuberculosis Day.” The “World Tuberculosis Day” was established in 1982 to promote TB prevention and early detection. It commemorated the 100th year anniversary of the discovery of M. tuberculosis on March 24, 1883 by the German bacteriologist Robert Koch. According to the TB Prevention Act (Article 4), Korea marks “The Tuberculosis Prevention Day” alongside the “World Tuberculosis Day” on March 24 to raise public awareness of the magnitude of the disease and the importance of prevention.
2015.03.25
View 8013
KAIST Develops a Credit-Card-Thick Flexible Lithium Ion Battery
Since the battery can be charged wirelessly, useful applications are expected including medical patches and smart cards. Professor Jang Wook Choi at KAIST’s Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and Dr. Jae Yong Song at the Korea Research Institute of Standards and Science jointly led research to invent a flexible lithium ion battery that is thinner than a credit card and can be charged wirelessly. Their research findings were published online in Nano Letters on March 6, 2015. Lithium ion batteries are widely used today in various electronics including mobile devices and electronic cars. Researchers said that their work could help accelerate the development of flexible and wearable electronics. Conventional lithium ion batteries are manufactured based on a layering technology, stacking up anodes, separating films, and cathodes like a sandwich, which makes it difficult to reduce their thickness. In addition, friction arises between layers, making the batteries impossible to bend. The coating films of electrodes easily come off, which contributes to the batteries’ poor performance. The research team abandoned the existing production technology. Instead, they removed the separating films, layered the cathodes and anodes collinearly on a plane, and created a partition between electrodes to eliminate potential problems, such as short circuits and voltage dips, commonly present in lithium ion batteries. After more than five thousand consecutive flexing experiments, the research team confirmed the possibility of a more flexible electrode structure while maintaining the battery performance comparable to the level of current lithium ion batteries. Flexible batteries can be applied to integrated smart cards, cosmetic and medical patches, and skin adhesive sensors that can control a computer with voice commands or gesture as seen in the movie “Iron Man.” Moreover, the team has successfully developed wireless-charging technology using electromagnetic induction and solar batteries. They are currently developing a mass production process to combine this planar battery technology and printing, to ultimately create a new paradigm to print semiconductors and batteries using 3D printers. Professor Choi said, “This new technology will contribute to diversifying patch functions as it is applicable to power various adhesive medical patches.” Picture 1: Medical patch (left) and flexible secondary battery (right) Picture 2: Diagram of flexible battery Picture 3: Smart card embedding flexible battery
2015.03.24
View 10761
Professor Jae-Kyu Lee's Memoir "Knowledge and Beyond"
Professor Jae-Kyu Lee of KAIST’s College of Business has recently published a book called Knowledge and Beyond (available only in Korean). It deals with selected aspects of science and the world around us. In Knowledge and Beyond, he expounds on his understanding of science, business, life, and religion. In part autobiographical, he describes his thirty-year career and his interaction with his past students who are now leading scientists and scholars in Korea, and offers some advice on how to better treasure life. Professor Lee also recounts his own life: his childhood, growing up and maturing with his mates, love at first sight of and his unconditional love towards his wife. With respect to science, he talks about the origin of knowledge and ways to find solutions to questions that seem almost impossible to answer and offers a few aphorisms, such as: “studying is more like a marathon, not a boxing match;” “do not predict, but plan your future” and “learn by head in class, learn by heart in life.” Knowledge and Beyond is a must read for those who have become exhausted by today’s competitive world, reminding readers of their life goals and paths. Professor Lee said, “I wrote this book for the young to share the true meaning of life over plain knowledge. You can never find out the true meaning of life unless you combine simple and spiritual knowledge, and I hope this book helps in showing a way to achieve it.” Professor Lee has taught at KAIST since 1985, and is currently the Dean of KAIST's Business College. He was formerly the Dean of KAIST College of Management, Director of KAIST EEWS (energy, environment, water, and sustainability) and the Vice Provost of the Singapore Management University’s School of Information Systems. He was also the President of The Korea Society of Management Information Systems and the President of Korea Intelligent Information System Society.
2015.03.24
View 6271
KVIP Opened in Pangyo
KAIST has opened the KAIST Venture Innovation Program (KVIP) in its Center for Industry Outreach, designed for executive and high-ranking officers of venture companies. Located in Pangyo Techno Valley, KAIST’s Center for Industry Outreach was established in collaboration with the government of Gyeonggi Province to support venture companies in Pangyo for business management training, venture networking, and university-industry cooperation. The program will be held every Monday for 12 weeks from April 13 to July 6 in KAIST’s Center for Industry Outreach. This executive education program mainly focuses on solving problems that arise when a medium-sized venture company is in the course of growing into a global corporation. The program is divided into four courses which will cover business management, competition in the global market, transformation of a company, and technological innovation. Professors from various departments at KAIST will give lectures on their fields. Professor Jaeseung Jeong from the Bio and Brain Engineering Department, Professor Hoi-Jun Yoo from the Electrical Engineering Department, Professor Sangmin Bae from the Industrial Design Department, and Professor Kwangjae Sung from the Business and Technology Management Department will each deliver lectures on brain engineering, semiconductor, design, and restructuring. Industry experts are also invited to give talks, including Dr. Dae-Gyu Byun, the Chief Executive Officer and President of HUMAX Electronics, Dr. Gwang-Cheol Choi, the Chief Executive Officer of SK Engineering & Construction, Mr. Il-young Kim, the former Chief Executive Officer of KT, Dr. Jae-hoon Jeong, the President of the Korea Institute for the Advancement of Technology (KIAT), Dr. Intak Bae, the Chief Executive Officer of Summit Partners, and Mr. Kyung-taek Kwak, a film director. The department has started recruiting first round applicants for the program, targeting executive and high-ranking officers of middle-sized venture companies. The details of the program can be found on its website, kvip.kaist.ac.kr.
2015.03.23
View 9520
<<
첫번째페이지
<
이전 페이지
91
92
93
94
95
96
97
98
99
100
>
다음 페이지
>>
마지막 페이지 177