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2017-09 04

[Academics]Chlor-alkali Electrolysis in Use

Professor Park Joo-yang of the Department of Civil and Environmental Engineering is an expert in the field of engineering. His paper, “SWRO brine reuse by diaphragm-type chlor-alkali electrolysis to produce alkali-activated slag” discusses a novel method of breaking down the brine after the desalination process. After the desalination process, what is left over is the brine (salt water with twice the concentration) and fresh water. Letting the brine out back into the ocean would cause a destruction of the ocean life cycle because thousands of tons of water is desalinated everyday and the concentration of salt would cause trouble for ocean farms. Through electrolysis process of the brine, chlorine gas and hydrogen gas are produced and this would be reused in diverse ways such as tap water. Park is explaining about the break down of brine process. Electrolysis process would leave chlor-alkali which would be used to produce alkali-activated slag used for pavements. Through the activation process of the alkali with the slag, it would turn into hard substance which is then processed to make pavement blocks. Since it is produced out of what should be discarded, it is economically efficient and is very durable, and also environmentally friendly. Some of the problems that Park is facing is that the research studies regarding this plant is almost reaching the developed level but has difficulty in terms of industrialization. Since brine has been let out into the ocean until nowadays which resulted in low handling expenses. For Park’s team to collect the brine and run the electrolysis process costs way too much even considering the fact that the slags would be produced at a reasonable cost. Handling costs outweigh the expenses of economic and environmental costs which makes it reluctant for companies to invest in producing such power plants. Park is continuously working to produce more environmentally friendly and cost efficient products through electrolysis processes although it may be a hard task to implement it. “I believe that continuously working in a field of expertise would open the doors for many opportunities,” concluded Park. “Continuously working in a field of expertise would open the doors for many opportunities.” Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Choi Min-ju

2017-07 30

[Academics][Researcher of the Month] World Class Solar Cell Developed

Professor Kim Eun-kyu of the Department of Physics is July’s Researcher of the Month for his active role in spreading knowledge in the field of physics. In his paper, “Iodide management in formamidinium-lead-halide-based perovskite layers for efficient solar cells”, Kim explains how he has created the ‘perovskite solar battery’ with the best efficiency in the world. Perovskite batteries have high efficiency and low production cost which is how it is gaining interest for the next generation solar energy source. Kim is explaining about the perovskite solar battery. Perovskite is material created out of anion, cation, and halide and is used inside the solar battery to create electricity. Kim has carried out his study along with Ulsan National Institute of Science Technology (UNIST) and Korea Research Institute of Chemical Technology (KRICT) and the paper has been introduced in the world renowned academic journal, Science. The research has been carried out through the support of Ministry of Science, ICT and Future Planning. The key theme of the research has been that through the control of halide, efficiency was to be raised from 20.0% to 22.1%. Currently, solar batteries are created with silicon materials but with the newly developed technology, new solar batteries could produce the highest efficiency with half the cost. Not only could it be used in the solar batteries, but they could also be used to produce new and renewable energy in the future with further integration of different technologies. Graphs showing the efficiency of the solar battery at 22.1% (Photo courtesy of Kim) Kim has started this study since all types of batteries should implement high level of efficiency. With high efficiency follows the lower production cost which was why this was important for the commercialization of the solar battery field. Kim and his research team are the best in the field currently showing the highest level of efficiency and still working for better technology. Although the technology itself has been developed to produce the most efficient solar batteries, mass production and commercialization problem is yet to be solved. Kim and his team are currently working on the perovskite battery to further test its safety and to control the halide. Although Kim and his research team have already reached their goal of creating the efficient battery and printing their paper on Science, further studies will be carried out to make the lives more convenient for people. Kim wishes to develop a more efficient solar battery in the future. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Kim Youn-soo

2017-07 09

[Academics]Speech Privacy in High-Speed Train Cabins

Professor Jeon Jin-yong of the Department of Architectural Engineering is an expert in the field of architectural acoustics. His paper, “Control of interior surface materials for speech privacy in high-speed train cabins,” discusses a novel method of using the sound masking technique along with the interior sound dynamics inside the train itself. At times, Speech Transmission Index (STI) is required in Europe and North America for announcements made in trains. During the period of 2012-15, with the support of Korea Agency for Infrastructure Technology Advancement (KAIA), Jeon had the opportunity to create architectural sound design for trains. Jeon is explaining about the importance of speech privacy. Jeon has experienced a serious problem about five years ago while riding a KTX train and had a chance to hear the ladies talking at the back about seven rows away from him. All the speeches being made by the ladies were being bounced on the shelves of the KTX and reached the other passengers which meant that everyone was listening to their conversation. After the experience, Jeon has decided to set up a new guideline on high speed trains for speech privacy between people. There are also surveys that point out that the most annoying noise on KTX users being the conversation between people by 31.8%. It is suggested by Jeon that the back of the chairs should be high and there should be the minimum space between the chairs in order to block out the conversation from being overheard. Since sound travels through the air and bounces from walls to ceilings, less space being provided for it to move around freely is a way to retain speech privacy. In addition, the material for chairs, ceilings, and side walls being high sound absorption material is suggested to reduce the interior noise. There is yet to be studies made on its fire resistance performance evaluation, weight lightening, and maintenance. Using sound tracking devices, Jeon was able to redesign the interior of the KTX. (Photo courtesy of Jeon) Sound masking has been one of the solutions as to provide speech privacy. It is the beating, squeaking and rattling noises that are created outside the train being intentionally flow into the train to cover up the conversation between people at about 50 to 60 dB. Speed trains with no interior noise has the features that allows the sound of human voice to travel through the space such as low ceiling, long space, and narrow walls. However, sound masking does not suggest interior noise to be too high since it would make the passengers dissatisfied. It means that there has to be enough interior noise in order to secure the speech privacy. Through Jeon’s studies made with computer programs and 1:10 scale sized KTX models, it is now suggested that high speed trains being produced nowadays provide enough speech privacy. After having contributed to the society through his novel findings, Jeon wishes to continue with the studies even further to solve the problem of noise complaint issues between neighbors through deep learning programs. Jeon wishes to contribute to the society through his sound interior designs. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Kim Youn-soo

2017-06 18

[Academics]Precise Diesel Engine Control in Action

Professor Sunwoo Myoung-ho of the Department of Automotive Engineering is an expert in the field of internal combustion engines and serves as a director at ACE lab. His paper, “Simplified Decoupler-Based Multivariable Controller with a Gain Scheduling Strategy for the Exhaust Gas Recirculation and Variable Geometry Turbocharger Systems in Diesel Engines,” discusses a novel method of applying a new control strategy in order to reduce the emission of nitroxide in diesel engines. Sunwoo explains precise diesel engine control and how it works. One critical disadvantage of diesel engine is that after the combustion, nitroxide is produced along with carbon monoxide and hydrocarbon and other chemicals. Once nitroxide meets water, it becomes nitrite hydrate (H2NO3) which could cause asthma and other bronchial diseases. There are two solutions that could be suggested to reducing nitroxide. First, is to control the engine in an extremely precise method, and, second, is to use catalyst to reduce nitroxide. One certain benefit that could arise from Sunwoo’s studies is that it makes diesel engines more of a “green car” in addition to being fuel efficient. As the production of nitroxide level gets significantly lower, it results in improvement of air pollution, less bronchial diseases for people and reduction of exhaust fume as well. Sunwoo has been researching on clean diesel, which focuses on making the diesel engines much cleaner and greener, for decades . Another program that Sunwoo, along with Hyundai Motor Company, has been focusing on for the past five years is meeting the Euro 7 standards. Euro 7 is the regulation of exhaust gases which is expected to go into effective in 2019. The draft for meeting the regulations has been produced so far. Sunwoo is planning to produce the cleanest internal combustion engine possible. "Think different, and act different." Sunwoo has provided some valuable advice for Hanyang students: “Find what you like the most. This is the primary mission of college life. Make your career different from others. This is the most important mission of all. Finally, never give up and do your best.” Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Kim Youn-soo

2017-05 30

[Academics][Researcher of the Month] Fusion Research in Enlightenment

Professor Choi Dong-ho of the Department of Medicine is June’s Researcher of the Month for his active role in developing knowledge in the field of medicine. In his paper, “Design and Fabrication of a Thin-Walled Free-Form Scaffold on the Basis of Medical Image Data and a 3D Printed Template: Its Potential Use in Bile Duct Regeneration”, Choi explains how he has created the bile duct, a body part that exports bile from liver to duodenum with 3D printer and being able to successfully conduct clinical demonstration on rabbits. Professor Choi explains about the 3D printing and its relation to artificial organs. For 20 years, Choi has been working on stem cell research which has eventually led to the stage of creating artificial organs with 3D printing techniques. Bile duct is one of the very sensitive body parts where it is hard to fix once problem occurs. Although there are artificial blood vessels, there has been no artificial bile ducts created. What makes it so complicated to make is that since bile is carried through the bile duct, it shrinks as time goes on if created with the material as commonly used as Gore-Tex. The material should be sturdy enough to withstand the bile, and it should be flexible enough to be sewed up as well which is definitely not an easy task. Process of creating bile duct through 3D printing (Photo courtesy of Choi) The diagram above depicts the process of creating bile duct. It first goes through the data acquisition through MRI images and 3D designing. As some cells are mixed up to the mold, it grows into the shape and size as designed. Important technique here is to develop the bio ink that congeals once it flows out of the 3D printing machine. Creating hydrogel and mixing up the stem cells to it is another important task to be completed. "I hope that what I create can be of help to people." Choi’s team is currently in the stage of obtaining patent in the techniques to create artificial organs through 3D printing. Since there are tremendous types of researches to be carried out through his studies, ranging from stem cell reprogramming to drug screening, Choi wishes that creating safe artificial organs in the end is what he wishes to achieve. “I am still doing translational research with various other departments and I hope that what I create can be of help to not only the patients, but even for my family as well in times of emergency,” concluded Choi. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Moon Hana

2017-05 14 Important News

[Academics]Production of Green Energy

Professor Lee Kun-sang of the Department of Earth Resources and Environmental Engineering is an expert in the field of earth resources. His paper, “Evaluation of CO2 injection in shale gas reservoirs with multi-component transport and geomechanical effects”, discusses a novel method of sequestrating carbon dioxide while extracting more shale gas efficiently. Professor Lee explains the findings depicted in his paper. Carbon dioxide, also known as CO2, continues to be a huge problem on the agenda nowadays. Numerous countries and environmental groups are trying to reduce CO2 emissions by imposing carbon tax. This may help reduce the CO2 emission rate but it does not actually reduce the total amount of CO2 in the air. What Lee has been studying may be a groundbreaking way to reduce CO2 in the atmosphere. The idea sparked up a few years ago when Lee and his students were funded the government through a research program to visit Pennsylvania State University in the US, that has been initiating research on this topic. The most well-known idea at the moment is to store the CO2 in the ground, but the problem with this was the economic drawbacks. Lee’s research focuses on injecting CO2 into shale reservoirs, which is a very tight sedimentary rock. Basic Diagram of CCS method. (Photo courtesy of Global CCS Institute) This method, also known as carbon capture and storage (CCS), is the act of separating CO2 from flue gases and collect them to store them underground. Just injecting CO2 into the ground results in high costs to store them, but Lee's approach not only takes care of CO2 in the air, but also allows for an easier extraction of shale gas as CO2 has a stronger tendency to absorb to shale. Simply put, CO2 increases the pressure into the methane gas while CO2 resides in the shale. All in all, CCS is economically and environmentally beneficial. Lee is continuously working to keep the natural properties of shale rock. Since it has a very meticulous feature, injecting oil or gas in them changes the properties a lot. Trying to develop the most refined model that would keep the properties of shale rock is one of Lee’s goals. Professor Lee has worked on a profitable model of reducing CO2 and collecting more methane gas that would benefit the environment. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Kim Youn-soo

2017-04 03 Important News

[Academics][Researcher of the Month] Detecting Ultra-Sensitive Benzene

Professor Kim Hyoun-woo of the Division of Materials Science and Engineering is April’s Researcher of the Month, for his active role in exploring the field of materials science and engineering. In his paper “Ultra-sensitive benzene detection by a novel approach: Core-shell nanowires combined with the Pd-functionalization”, Kim explains how the detection of benzene gas has become much more efficient than ever. The palladium being extra sensitive to benzene gas has been the key to the detection technique which has drawn attention in this field. Kim has discovered the link between palladium and benzene gas. The Pd-functionalized SnO2-ZnO C-S NW is the substance developed by Kim in order to detect benzene, a toxic gas. Since nano-sized palladium particles are added on a cell with SnO2 and ZnO covered on top, the sensor produces a spillover effect, distributing the benzene gas particles along the conduction band. The effectiveness of Kim's model is proven through the gas response. (Photo courtesy of Kim) This is important since benzene gas can be found in everyday life. It is inside cigarette smoke, smog, exhaust fumes and may be found in new houses, creating sick house syndrome. Through Kim’s finding, this benzene gas, which could be lethal to human lives, can be spotted in a much more sensitive manner. Since the sensors and cells created in a smaller size would lead to higher sensitivity, the particles have been selected in nano-sizes. The only problem that could arise with this sensor is that it depends heavily upon the selectivity of which gas it wants to detect. The compatibility between different particles could create great results as Kim has found out in the case of palladium and benzene, while in other cases, disastrous results may be spawned. Kim explains how his model works. Kim wishes to develop better usage of sensors than those that are being distributed in every day life as of now. “I want to find the best usage of a new sensing principle totally different from the current ones,” said Kim. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Choi Min-ju

2017-02 06

[Academics][Researcher of the Month] Al-FCG Ready for Action

Professor Sun Yang-guk of the Department of Energy Engineering is February’s Researcher of the Month for his active role in exploring the field of energy engineering. In his paper, “Compositionally Graded Cathode Material with Long-Term Cycling Stability for Electric Vehicles Application”, Sun explains how adding aluminum into the cathode makes batteries last longer and become more stable compared to other rates of composition. The Al-FCG61 that Sun has developed has shown a high rate of energy efficiency even at 100% depth of discharge (DOD), which draws attention in the field. Sun explains his research with assisted diagrams. As the supply and demand of the electric vehicle is on the rise, most of the batteries in the market last from 150km to 400km, meaning that once the battery is fully charged, the car would move between the distance within. What accounts for the difference is the capacity as to how much cathode can hold up. In order for cars to go beyond 300km at least, the capacity of the cathode would have to be over 200A/h. The only problem to this is that it gets difficult to make it stable and it could blow up. There are various prototypes ranging from generation 1 to generation 4 and the study carried out in Sun's paper is on generation 3. Gradients of different components from inner to outer parts of nickel particle. (Photo courtesy of Sun) Capacity retention, which is the lifespan of a battery, would rise with 61% of nickel with FCG full concentration gradient, which is what Sun has developed in order to create a more stable and long-lasting battery that would hold a larger capacity. Within the mold, Sun has created a two-way particle that contains a high percentage of nickel inside with lower percentage of nickel on the outside. This concentration gradient is created due to the fact that nickel has its advantage of being able to increase the capacity of the battery while it makes the battery more unstable with exothermic reaction. Along with the nickel, Sun has increased the percentage of the manganese inside the particle since it has the advantage of making the cathode more stable. Depth of discharge (DOD) is the rate at which battery is either charged 60% or 100%, and this is tested before electric vehicles are sold for inspection. The average usage of an electric vehicle is at around 2,500 cycles for 10 years, and the Al-FCG has proven to be more energy efficient even at 100%. Most of the batteries do not last long at DOD100 due to the expansion of volume inside the battery. This means that the battery would lose its efficiency as time goes. Al-FCG has shown its Coulombic efficiency rate of 84.5% even at DOD100, while batteries currently in the market show an average of 50% at 2000 cycles. This new battery devised by Sun is not only more energy efficient, but more cost efficient as well. Sun wishes to make more efficient batteries. Sun is continuously researching to keep the DOD level at 100% even after 2000 cycles. With his findings, the electric vehicle industry would definitely benefit hugely in terms of cost and energy efficiency. With different materials, Sun wishes to develop other types of batteries that would bring more comfort to society. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Kim Youn-soo

2016-12 27 Important News

[Academics]Semi-Conductors for Convenience

Professor Park Jea-gun of the Department of Electronic Engineering is an expert in the field of semi-conductors, having researched it for 31 years now. His paper, “Effect of double MgO tunneling barrier on thermal stability and TMR ratio for perpendicular MTJ spin-valve with tungsten layers“, discusses the magnetic memory, which is a totally different type of memory device in the current market other than the DRAM (dynamic random-access memory) and the NAND (negative-AND) flash memory. As semi-conductors are made into smaller models, it becomes faster as the electric power it needs gets lower, and the cost to produce the model gets lower as well. In the world of IT, the reading and writing of information should get faster as time goes. But since there are limits to the current technology in reducing the size of the semi-conductors smaller than 10 nanometers, there have been attempts to make a different type of model that could replace the DRAM technology. Park explains about the magnetic memory being developed at HYU. Tohoku University (THU) in Japan came up with the idea of magnetic memory from which Hanyang University (HYU), along with Samsung Electronics, SK Hynix, and the Korean government invested 40 billion won to develop a semi-conductor research facility. There are only two other facilities that are able to produce such novel technology, which are in the United States and Belgium. Since the idea provided by THU was not a fully developed one, Park changed the material needed to produce it into tungsten. The result has been quite successful in that it can now be activated even at 400 degrees while what was proposed at THU could only hold up to 300 degrees. The original memory types used to have what is called a capacitor. By charging electrons in it or discharging it, the digital signal becomes 1 and 0 respectively. As for the magnetic memory, it has two magnetic layers. One has fixed electron while the other has a free one. In between the two layers, there is an insulation layer. The fixed electron always flows in the same direction while the free electron flows in the direction of the electric power. Once the two electrons are flowing in the same direction, more electric power flows and it has lower resistance, which reads data 0 state while the opposite means data 1. In other words, it can be said that the way to produce D0 and D1 is different from the original type in charging the electrons and discharging them, or by letting the electrons flow in either the same or opposite direction. The sizes of DRAM and NAND would be difficult to get smaller than 10 nm. (Photo courtesy of Park) Evidently, there are advantages to the magnetic memory in that the changes in the direction of flow of electrons are very fast. Charging and discharging capacitors take much longer and consumes more electric power as well. In addition, the capacitor needs a certain surface area, while this new form of memory gets faster as the size gets smaller. It can be said that this nano structure element is an absolute must when it comes to scaling down the size of memory storage. It is believed that this technology would be necessary in developing the internet of things, or IOT technology, once it has been stabilized. Magnetic memory has now been successfully installed onto a System on Chip (SoC). This technology is crucial for IOT technology, and it is predicted that the memory technology at this stage will not be in use by 2022 to 2025. Park wishes that his technology would make people's lives more easier. Park believes that by developing the original technology and being credited for the paper would eventually be a huge contribution to the Korean society where the semi-conductor industry accounts for about 5% of Korean GDP. Through his technology, Park aims to make people feel the comfort of advanced technology when it comes to our daily lives and the information-oriented era. Kim Seung-jun nzdave94@hanyang.ac.kr Photo by Kim Youn-soo

2016-11 20 Important News

[Academics]Institutionalization of the green certification scheme

Professor Kim Hong-bae of the Department of Urban Planning & Engineering is an expert in the field of urban planning. His paper, “A cost-benefit analysis for the institutionalization of the green certification scheme”, discusses about what would be beneficial when it comes to achieving the green certification. Green certification is the standardized certificate used to prove the suitability of Green technology and products. As for other developed countries, there has been green certifications since the 1990s following the concerns of environmental pollution. For instance, Great Britain has the BREEAM, Japan has CASBEE and United States has the LEED. These institutionalized green certificates are competing to become the world standard. Although Korea now has GBCC, it is not institutionally stabilized compared to other countries yet. Other countries provide the green certification in terms of community, rather than single building itself while Korea is on its way to broadening its spectrum towards giving communities the green certification. ▲ Kim explains about the green certification What is so special about Kim’s paper was that it has provided a deep insight into whether green certification was something that really provides people with benefits in life or not. Through the cost benefit analysis, he has provided the guidelines to how the system would be generally constructed. By providing low carbonizing 45 sectors ranging from industry to policies, Kim has divided the qualification standard and it has its meanings in that social costs and benefits are derived. Most of the standards are very straightforward. However, there are some of the ambiguous points to be digitized into measurements which include pride or self-esteem. Most of the measurements are easier to make for instance, the market value of the house that individuals live in. However, it is hard to show the pride in terms of numerical values to be seen. This is where the contingent valuation method (CVM) comes into action. This explains the “willingness to pay” and digitizes the inherent value inside individuals. ▲ Kim expresses that energy should be saved Some of the studies that Kim is engaged in currently is related to energy harvesting. By recycling the energy wasted into creating a new source of energy, it has its huge meanings. Also, Kim has pointed out a special point in that electric cars do not actually lower the carbon dioxide level nationally. “Although in regions where electric cars operate will show lower signs of carbon dioxide level, the regions where electricity is produced will show greater levels of carbon dioxide which means that nationally, it breaks even,” said Kim. The goal of Kim’s studies leads to one simple logic. In order to achieve low carbon, low energy comes first. The responsibility to saving energy would lead to a lower level of carbon dioxide, which is believed to be one of the worst factors that affect global warming. People need to actively engage in actions such as car sharing or even the smallest actions such as saving water, electricity and the environment as a whole. Kim Seung-jun nzdave94@hanyang.ac.kr