Ministry Of Knowledge Economy Research Articles

First Principles Investigation of Grain Boundary Effects in Perovskite-Type Lithium Lanthanum Titanate Solid Electrolyte

Lithium lanthanum titanate (LLTO) is considered a particularly promising candidate for use as an electrolyte in all-solid-state lithium ion batteries due its good electrochemical stability and high ionic conductivity. However, measured values for the ionic conductivity of LLTO fall far below theoretical predictions, an incongruity which has been attributed to the presence of grain boundaries. Furthermore, recent experimental work has shown that lithium dendrite growth occurs along the grain boundaries in LLTO. While experimental studies have been able to reveal the detailed microstructure of polycrystalline LLTO, but little effort has been made to identify the fundamental mechanisms at work within the grain boundaries which lead to to suppressed ionic conductivity and Li dendrite growth. Using ab-initio calculations, we examine the electronic character of LLTO grain boundaries and investigate the impact of the defect states on ion transport and dendrite formation. Based on a fundamental understanding of the atomic and electronic character of LLTO grain boundaries, material design approaches are proposed to mitigate the impact of grain boundary behavior and improve the viability of LLTO as a practical solid electrolyte. This work was supported by the International Energy Joint R&D Program (No. 20168510011350) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Knowledge Economy, Korean government. This work is also supported by the L&F Co.’s World Class 300 Project of the Korea Institute of Advancement of Technology (KIAT) funded by the Ministry of Trade, industry and Energy (No.S2483103).

(Invited) Rational Design of Battery Cathode Materials

We will discuss about applying ‘materials by design’ and validation experimental research on high capacity cathode materials for Li and Na ion batteries (LIB and NIB). Using the first-principles density functional theory (DFT) method, we have designed electrode materials for battery cathodes, and subsequently performed experimental studies to validate the material designs. Through an integrated material design - experiment research, we have developed highly efficient cathode materials for NIB. [1] Furthermore, using the DFT based stability analysis of Li(Ni,Mn,Co)O2 (NMC) cathode materials, the underlying mechanisms of stability change in Ni-rich NMC cathodes are elucidated over the range of 30 – 100 % Ni concentration in metal composition. [2-6] Surface analysis of Ni-rich NMC has also provided insights on the degradation mechanisms (both chemical and mechanical) facilitating to develop a design strategy to improve the stability of Ni-rich NMC over 80% Ni contents. [7] This work was also supported by the International Energy Joint R & D Program (No. 20168510011350) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Knowledge Economy, Korean government. [1] D. Kim, M. Cho, K. Cho, “Rational Design of Na(Li1/3Mn2/3)O-2 Operated by Anionic Redox Reactions for Advanced Sodium-Ion Batteries,” Adv Mater 29(33), 1701788 (2017). [2] Chaoping Liang, F, Kong, R. Longo, Santosh KC, Jeom-Soo Kim, SangHoon Jeon, SuAn Choi, K. Cho, “Unraveling the Origin of Instability in Ni-Rich LiNi1−2xCoxMnxO2 (NCM) Cathode Materials,” The Journal of Physical Chemistry C 120(12), 6383–6393 (Mar. 31, 2016) [3] R. C. Longo, F. Kong, C. Liang, D. -H. Yeon, J. Yoon, J. -H. Park, S. -G. Doo and K. Cho, “Transition Metal Ordering Optimization for High-Reversible Capacity Positive Electrode Materials in the Li-Ni-Co-Mn Pseudoquaternary System,” Journal of Physical Chemistry C 120(16), 8540-8549 (Apr. 28, 2016). [4] F. Kong, C. Liang, L. C. Roberto, D.-H. Yeon, Y. Zheng, J.-H. Park, S.-G. Doo and K. Cho, “Conflicting Roles of Anion Doping on the Electrochemical Performances of Li-ion Battery Cathode Materials”, Chem. Mater. 28(19), 6942–6952 (Oct. 11, 2016) [5] Chaoping Liang, Roberto C. Longo, Fantai Kong, Chenxi Zhang, Yifan Nie, Yongping Zheng, Jeom-Soo Kim, SangHoon Jeon, SuAn Choi, and K. Cho, “Obstacles toward unity efficiency of LiNi1-2xCoxMnxO2 (x=0~1/3) (NCM) cathode materials: Insights from ab initio calculations” Journal of Power Source 340, 217-228 (2017). [6] C. Liang, F. Kong, R. Longo, C. Zhang, Y. Nie, Y. Zheng, K. Cho, “Site-dependent multicomponent doping strategy for Ni-rich LiNi1-2yCoyMnyO2 (y=1/12) cathode materials for Li-ion batteries,” J. Mater. Chem. A 5(48), 25303-25313 (Dec. 2017). [7] C. Liang, R. Longo, F. Kong, C. Zhang, Y. Nie, Y. Zheng, K. Cho, “Ab initio Study on Surface Segregation and Anisotropy of Ni-rich LiNi1-2yCoyMnyO2 (NCM) (y ≤ 0.1) Cathodes,” ACS Appl. Mater. Inter. (2018).

The impact of technology capability, human resources, internationalization, market resources, and customer satisfaction on annual sales growth rates of Korean software firms

This study investigates the competitive factors of software firms that participated in the Korea Software Firm Competitiveness Awards, a nationwide project supported by the Ministry of Knowledge Economy that studies the performance of software firms in Korea. The study applies concepts from hierarchical multiple regression analysis to develop a model to assess the relationship between the competitive factors of software firms and firm performance. The developed model was validated through a field survey of 79 software firms in Korea. The survey results show a significant relationship between competitive factors and firm performance, as well as the relative influence of significant variables. The findings provide two important implications: first, from a management perspective, software firms in Korea focus on human resources based on technology development in the domestic market, and second, from a policy perspective, the government supports the establishment of external capabilities (internationalization and partnerships) for software firms. These findings are available to researchers, policy makers, software developers, and other market players, and contribute to the literature on the importance of competitive factors.

Discrete bonded particle modelling of fault activation near a nuclear waste repository site and comparison to static rupture earthquake scaling laws

The results of this study are presented by courtesy of the Swedish Radiation Safety Authority (project SSM2013-3839 and SSM2014-3668) and have been produced in the context of a geo-mechanical study by GFZ German Research Centre for Geosciences in collaboration with Seoul National University. Financial support to Ki-Bok Min was also given by the New and Renewable Energy Technology Development Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) through a grant funded by the Korean Government's Ministry of Knowledge Economy (No. 20123010110010).

Corrigendum: Synthesis of Reduced Graphene Oxide-Modified LiMn0.75Fe0.25PO4 Microspheres by Salt-Assisted Spray Drying for High-Performance Lithium-Ion Batteries.

Scientific Reports 6: Article number: 26686; published online: 25 May 2016; updated: 11 July 2016 The Acknowledgements section in this Article is incomplete. “This work was supported by the energy efficiency and resources grant (No: 20122010100140) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) funded by the Ministry of Knowledge Economy, Korean government.

Thermodynamic Behavior of Manganese Oxide in Lime-based Manganese Smelting Slags

This work was supported by the third Stage of Brain Korea 21 Plus Project and the Industrial Strategy Technology Development (No. 10033389, Development of e-FERA Technology) through a grant provided by the Ministry of Knowledge Economy.

Comprehension and redesign of recently introduced water-sport prohibitive symbols in South Korea

The goal of this study is to evaluate the comprehensibility of recently introduced water-sport prohibitive symbols by the Ministry of Knowledge Economy (MKE, now the Ministry of Trade, Industry and Energy) of South Korea, and to redesign the poorly comprehended symbols based on participants' feedback and three universal ergonomic principles. Evaluation of comprehensibility and cognitive features of fourteen water-sport prohibitive symbols were conducted with forty Korean participants. Only two out of fourteen symbols have comprehension rates higher than the level recommended by ISO standard. Four poorly comprehended symbols are redesigned based on ergonomic design principles and participants’ feedback. A follow-up experiment with another group of twenty Korean participants was conducted to verify the effectiveness of the redesign process and results showed redesigned symbols have better adherence to ergonomic design principles and enhanced comprehensibility than the original ones. The findings may serve as a useful input for researchers and designers in creating easily comprehended symbols to promote safety. Relevance to industryWarning symbols have long been used as an interface to communicate critical situation-specific information to prospective users in industrial undertakings so that the risk of accidents and injuries can be reduced. The findings of this study provide useful information for designers in developing easily comprehended symbols to promote safety.

(Invited) Ru-Based Binary or Ternary Thin Films By Atomic Layer Deposition for a Seedless Cu Interconnects

Ru has been suggested as a diffusion barrier that is compatible with the direct plating of Cu. However, previous studies showed that Ru itself is not a suitable diffusion barrier for Cu metallization due mainly to its poor microstructure with polycrystalline columnar grains. This study developed several Ru-based multi-component thin films, RuMn, RuSiN, and RuAlO using atomic layer deposition (ALD) process, which are compatible with the direct plating of Cu as well as show better diffusion barrier performance against Cu than Ru. Mn, SiNx, AlOx were incorporated into the Ru by combining the Ru and corresponding ALD cycles, and Ru-based binary alloy, RuMn, ternary thin films, RuSiN and RuAlO, were fabricated at 225 oC. As a typical example, the results on ALD-RuAlO were shortly described. The step coverage of ALD-RuAlO was perfect at contact holes with an aspect ratio of ~ 25 (top-opening diameter: ~ 85 nm). XRD and TEM results indicate that ALD-Ru film prepared without AlOx ALD cycle forms a polycrystalline structure with columnar grains. But, with incorporating the AlOx cycles, RuAlO films were formed with non-columnar grains and nano-crystalline microstructure consisting of Ru nano-crystals separated by amorphous AlOx matrix. XRD analysis showed that the structure of Cu/ALD-RuAlO (8 nm)/Si was stable after annealing at 600 oC for 30 minute while Cu/Ru (15 nm)/Si structure was failed after annealing at 450 oC. It was also shown that the electroplating of Cu was directly achieved on a very thin (~8-nm-thick) RuAlO film at blanket and pattern wafer. In the case of binary ALD-RuMn film, it should be noted that after annealing ALD-RuMn film at 500 oC, the self-formation of Mn silicate barrier between Ru(Mn) film and SiO2 was confirmed based on XRD and TEM analysis, which was due to the diffusion of Mn into underlying SiO2, resulting in better diffusion barrier performance than Ru counterpart. Acknowledgements This work was supported by the Technology Innovation Program (Industrial Strategic technology development program, 10035430, Development of reliable fine-pitch metallization technologies) funded by the Ministry of Knowledge Economy (MKE, Korea) and also partially supported by Tanaka Precious Metals, Japan.

Comprehensibility of Newly Introduced Water-sport Prohibitive Signs in Korea by Koreans and Westerners

Objective: The goal of this study is to evaluate the comprehensibility of the newly introduced water-sport prohibitive signs by the Ministry of Knowledge Economy (MKE, later merged into the Ministry of Trade, Industry and Energy) among Koreans and westerners, and to check whether the comprehensibility is affected by cultural differences.BR Background: The Ministry of Knowledge Economy had newly introduced fourteen water-sport prohibitive signs at the end of 2011 to alert people to potentially dangerous situations. However, no studies had been found so far to review or assess their comprehensibility.BR Method: Comprehensibility tests of fourteen water-sport prohibitive signs were conducted with forty Koreans and forty Westerners in two sequential sessions. In session I, participants were asked to guess the meaning of each sign verbally in an open-ended test. In session II, participants were encouraged to provide feedback for each sign after its intended meaning was given.BR Results: Only two out of fourteen signs satisfied the comprehension rate (67%) recommended by ISO standard for both groups (Koreans and Westerners). Cultural difference between Koreans and westerners significantly affect the comprehension rates of the investigated signs, and Westerners exhibit better overall comprehension than Koreans. Five poorly comprehended signs for both Korean and Western groups were identified.BR Conclusion: The recently introduced water-sport prohibitive warning signs by MKE still need a lot of improvements in order to be implemented nationally or internationally. There were significant differences in the signs" comprehensibility between Koreans and westerners.BR Application: The findings may serve as a useful input for researchers and watersport sign designers in creating easy-to-comprehend safety signs.

개방형 한국어 지식 대사전 전문용어 신분류 체계 설정 및 재분류

A new classification system with 9 main categories and 56 subcategories for the Open Korean Knowledge Dictionary is proposed. The classification system setup is to prepare for the standard classification system to be used to manage effectively vast of terminologies which were published in the Open Korean Knowledge Dictionary and is meant to enhance the fifteen-year old classification system for the standard korean great dictionary to match up to the trend of the modern terminology. The new terminology classification system covering all the academic areas such as humanity, sociology, politics, science, medicine, agriculture, engineering, etc, is designed and proposed after investigating several classification systems. The classification system setup procedures follow as ◦ The classification system is designed and planed by both the classification system and the academic expert. ◦ Classification system design covers all the academic areas following National Science and Technology standard classification system after investigating several classification systems such as the National Research Foundation, National Science and Technology Standard Act, Ministry of Knowledge Economy. ◦ Poll and survey is made to collect comments from total 93 members of several academic areas. ◦ The poll result is reviewed among working group members and utilized to update the new terminology classification system. Reclassifications are made for the around 200,000 terms in electricity, computer, medicine, pharmacy, biology, and economics according to the new terminology classification system.

Visualization in the Contact Line Region of an Evaporating Nanofluid Drop

Photogallery Entry 13

First Principles and Experimental Study of Phase Transformation Mechanism of Li-Rich Oxide Cathode Material in Li-Ion Battery

Li-rich oxide cathode is one of the most promising high capacity cathode materials for the next commercialized Li-ion battery application, and its composition can be described as a mixture of Li2MnO3 and Li(TM)O2(TM: Transition metal). Li-rich cathode material has large capacity based on relatively cheap Mn oxide, and it is easy to synthesize. However, the Li-rich cathode material has critical material challenges such as capacity degradation and voltage drop. It has been reported that the main source of the material challenge is related to phase transformation inside the bulk cathode material during charge/discharge processes.In this work, detailed phase transformation mechanism of Li2MnO3 is investigated by combining the experimental and computational approaches to develop fundamental understanding on the atomic scale processes. The structure of Li-rich oxide is a composite of Li2MnO3 and layered Li(TM)O2, and the monoclinic layered structure of Li2MnO3 is known to be the source of the degradation problems. We have observed the evidence of phase transformation in Li2MnO3experimentally, and a theoretical analysis based on density functional theory calculations is combined with experimental data for a systematic comparative study.For experimental study, we have synthesized Li2MnO3 powder by solid state method at low temperature following the literature procedures. Using this powder, we made a coin cell with standard Li reference electrode, and the CV measurement shows the phase transformation during charge/discharge processes. First, basic powder characterization was conducted through XRD, and SEM analyses. Second, coin cell was assembled for cyclic performance test, and charge/discharge profile and cyclic voltammogram were obtained. From the experimental investigation, synthesized Li2MnO3is identified as monoclinic C2/m space group structure and their particle size is around 200~300 nm. The evidences of phase transformation are found from cyclic charge/discharge profile as well as cyclic voltammogram. As reaction cycle is progressed, charge/discharge capacity operated under 4.6 V has a steady increase indicating that, the initial active material is getting transformed to another phase with lower reaction voltage than 4.6 V. As described in Fig. 1, we could observe the changes of charge/discharge profile and reaction voltage fundamentally caused by phase transformation consistent with similar previous experiment studies. As observed before, the first charge voltage is around 4.6 V, but the charge voltage changes to around 3.2 V as cycle goes on. Remarkably, discharge voltage reveals at three different values around 2.8 V, 3.3 V, and 4.0 V, suggesting that there are three different transformed phases inside the active material as the cycle goes on.To understand this and similar experimental observations of phase transformation, we have examined how and why it could happen in terms of thermodynamics and kinetics based on density functional theory investigation. In case of thermodynamic study, phase stability, intercalation voltage, electronic charge, and electronic structures are studied. From phase stability and intercalation voltage analyses, we would estimate when initial structure could be transformed. The electronic charge and partial density of state for both initial and transformed structure (whose Mn ion is migrated) are investigated for structure stability and physical/chemical characters. We found that thermodynamic stability of structures and the changes in bonding characters between Mn and O ions are to the main cause of phase transformation. For kinetic analysis, we investigated the migration barriers of Li and Mn ions in the Li2MnO3framework with controlled delithiation. Based on the kinetic calculation results, we could show the possibility of Li and Mn ion migrations with different Li contents in active material. As shown in Fig 2, not only the possibility and the delithiation effect of phase transformation, but also the detailed Mn migration mechanism could be predicted providing atomic scale explanation of phase transformation. As a result, detailed phase transformation mechanism could be quantitative understood, and it would be possible to suppress such phase transformation based on theoretical studies on material design such as doping on effect the electronic structure analyses.By understanding detailed phase transformation mechanism of Li2MnO3, we are developing material modification strategy to solve capacity degradation and voltage drop problems. The developed strategy will be critically validated by experimental implementation of the designed material modification. Such combined material design and experimental validation approaches will accelerated the high capacity cathode material development based on atomic scale understanding.This work was supported by the Industrial Strategic technology development program(10041589) funded by the Ministry of Knowledge Economy(MKE, Korea)

Intercalation Induced Stress Effects of the Core-Shell Anode Materials for Lithium Ion Battery

Rechargeable lithium-ion batteries are widely used as electric power for portable electronics and electric vehicle due to its excellent characteristics such as high voltage, and high energy density.Silicon is a promising anode material for high performance lithium ion batteries, as it has very high theoretical reversible specific capacity (3579 mAh/g for Li15Si4) at room temperature. However, implementation of silicon-based materials has some challenges. Active particle pulverization caused by the large volume expansion leads to the loss of electrical contacts at the electrode. It is recognized as one of the major capacity fade with repeated charges–discharge cycling. Various experimental studies have been attempted to overcome this mechanical degradation using fabrication of nano-sized structures, porous materials and core-shell structures.Especially, core–shell structure exhibits improved physical and chemical properties : suppressing large volume expansion resulting in inner core fracture, preventing the inner core from forming excessive SEI and enhanced electrical conductivity.Experimental results have already provided a core-shell structure capability for LIBs. However, the analysis of core-shell structure using model simulation is not well explored to support experimental results.Therefore, we propose a model of the intercalation-induced stresses for core-shell particles with various morphologies and deal with stress effects on Lithium ion diffusion in active particles. The radial compressive stress at the core-shell interface mitigates the crack growth of active core materials and this radial stress eventually enhances the cycling performance of LIBs. However, this compressive stress influences on the lithium ion diffusion and affects the electrochemical behavior over their single-component counterpart. So, we suggest the desirable range of shell thickness and allowable shapes of core-shell structure. ACKNOWLEDGEMENT This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST) (No. 2012R1A3A2048841) and by the Industrial Strategic technology development program (10041589) funded by the Ministry of Knowledge Economy (MKE, Korea)

First Principles and Experimental Study of Surface Redox Reactions in Li2MnO3

The development of rechargeable lithium-ion batteries (LIB) has progressed rapidly to meet the demand for consumer electronic devices such as cellular phones and laptop computers, and the recent demands for larger energy storage applications (xEV and grid storage) require further development of LIB or alternative energy storage technology. Among possible alternative cathode materials compared to the currently used material LiCoO2, Li-rich compounds xLi2MnO3·(1-x)LiMO2 (M = Ni, Co, Mn) are the most promising candidate with higher capacity, lower cost and absence of toxic element. Within the two-component composite compounds, Li2MnO3 plays a central role in increasing the capacity of the compounds and independently possess a high theoretical capacity of 460 mAh/g (if the entire lithium is utilized). Although the Li2MnO3 is not electrochemically active between 2.0V and 4.4V, it is active to extract lithium ions over 4.5V. During the initial delithiation process, Li2MnO3 is known to transform into layered LiMnO2structure, and the subsequent charge/discharge cycling induces a gradual phase transformation to the spinel structure, resulting in lowering voltage plateau and a large irreversible capacity accompanied by oxygen loss. To overcome these capacity loss problems, diverse approaches have been made to improve electrochemical properties of the cathode materials: adjusting the relative ratio of different transition metal ions, coating layers on the particles, and synthesizing at various temperature to control specific surface area.Even though the bulk properties of cathode materials have been studied by many research groups, the surface properties of cathode have seldom been researched so far. Specifically, theoretical study on cathode surface has been rarely performed even though major reactions and chemical transformations occur near the surface and interfaces between different phases. Recently, several research groups highlighted and reported experimental observations of a phase transformation from the layered structure to spinel phase at the particle surface upon the first charge cycle. However, it is still unclear and controversial for theoretical and fundamental understanding on the mechanism of phase transformations. Without the basic understanding based on detailed atomic scale theoretical analysis, many problems of LIB materials will take extreme efforts and time to resolve the problems.In the present paper, we established a fundamental understanding on the origin of phase transformation at the surface through first principles study of interface models. The theoretical findings suggest unusual redox activities of the surface layers of Li2MnO3which is confirmed by detailed experimental study. These theoretical and experimental findings provide basic understanding to improve performance degradation by phase transformation.For the experimental study, coin cells are made with Li2MnO3 cathode and Li reference electrode, and variation of voltage between 2.0 V and various limiting voltage is applied to the electrochemical test with a constant current at room temperature and under 0.05 C-rate during 10 cycles. There is a small amount of redox capacity (4 mAh/g) at lower voltage as shown in Fig. 1a inset, and Figs. 1d-f show 10 mAh/g capacity during subsequent 10 cycles with lower limiting voltage of 4.1-4.3 V. Fig. 1a shows voltage plateau at 4.6 V extracting Li in the bulk Li2MnO3 with accompanying phase change to layered LiMnO2with lower voltage during subsequent cycles.For the modeling study, in order to elucidate the low voltage redox mechanism observed in Fig. 1, we examined the Li intercalation potential at the surface using the model shown in Fig. 2. The model interface contains stoichiometric ratio of constituents (Li : Mn :O = 2 : 1 : 3) split into two regions of a semi-infinite bulk (SIB), which is inactive at low voltage (4-4.5 V), and a interface layer (IFL) exposed to vaccum, which is calculated to be active at low voltage (~4 V).Finally, detailed electronic structures of the interface model show different oxidation state of surface Mn atoms compared to the fully oxidized bulk Mn4+ within the bulk. Since the high activation potential of 4.6 V of bulk Mn is known to be related to electron extraction from oxygen atoms coordinating Mn4+, any lower Mn oxidation state on the surface would reduce the delithiation potential comparable to those of layered LiMnO2 and spinel (3-4 V). Furthermore, delithiation potential at the surface show strong dependence on the Li location in Mn-layer (4.6 V) and Li-layer (4V) at the surface of Li2MnO3. The preferential delithiation of Li from the surface Li-layer would facilitate the Mn atom migration to the Li-layer causing spinel phase transformation at the surface. These underlying understanding mechanisms of the surface will provide a conceptual basis to develop diverse approached to suppress phase transitions in the cathode materials in LIB, which is our current modeling and experimental research topics.This work was supported by the Industrial Strategic technology development program(10041589) funded by the Ministry of Knowledge Economy(MKE, Korea)

Multiscale Analysis of Lithiation of Si Anode of Li-Ion Batteries: First Principle Calculation and Finite Element Analysis

Silicon is known to have large Li storage capacity up to 4.4 Li atoms per Si atom in Li22Si5 compounds, but the large volume change and the mechanical stress during the charge-discharge cycles have damaged the electrode structures leading to rapid capacity fade.Recently, Cui et al. have applied the silicon nanowire structures to avoid the mechanical stresses induced by the volume change and demonstrated promising capacity of the silicon nanowire anode for Li ion batteries. However, there are many issues on the lithiation in silicon anode to understand its physics of mechanism.The kinetics of Li diffusion in Si anode is a main issue because the mechanical failure of Si active material significantly affects the stress state during cycles. In this presentation, we analyze the Li diffusivity in bulk-Si and LixSi (x>1) systems using first principle calculation and obtain the Li diffusion coefficient as function of Li concentration using kinetic Monte Carlo simulation. We also study the difference of lithiation between crystalline silicon and amorphous silicon.Based on the first principle calculation, we check the mechanical stability of Si anode in various shape and charged condition using the diffusion-induced macroscopic model based on finite element method. Our multiscale analysis can provide reliable predictions on the stability with respect to the stress deviation according to size and shape of Si nanowire including charge rates. We also construct a non-dimensional design criteria equation for allowable stresses based on Buckingham-Pi theorem. Moreover, we analyze stress of more complex Si nanowire called Si nanotube and explain why pre-lithiated Si nanowire could have better cycle-ability compared to pristine one.The multiscale approaches of Si anode from atomic scale to continuum scales help understand the mechanical failure of the Si anode in terms of the microstructure variations, and suggest a guideline to improve the Si anode performance for LIBs. ACKNOWLEDGEMENT This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST) (No. 2012R1A3A2048841) and by the Industrial Strategic technology development program (10041589) funded by the Ministry of Knowledge Economy (MKE, Korea)

SU-E-T-63: Carotid Sparing Tomohelical Three Dimensional Conformal Radiotherapy for T1N0 Glottic Cancer

Purpose: We investigated the dosimetric benefit and treatment efficiency of carotid-sparing TomoHelical (TH) three-dimensional conformal radiotherapy (3DCRT) for early glottic cancer. Methods: Computed tomography (CT) simulation was performed for 10 patients with early-stage (T1N0M0) glottic squamous cell carcinoma. The clinical target volume, planning target volume (PTV), carotid artery (CA), and spinal cord (SP) were delineated for each CT data set. Two-field 3DCRT (2F-3DCRT), three-field intensity-modulated radiation therapy (IMRT) (3F-IMRT), TomoHelical-IMRT (TH-IMRT), and TH-3DCRT plans were generated, with a total prescribed dose of 67.5 Gy in 30 fractions to the PTV for each patient. In order to evaluate plan quality, dosimetric characteristics were compared in terms of the conformity index (CI) and homogeneity index (HI) for the PTV, V35, V50, and V63 for the CAs and in terms of the maximum dose for the SP. Additionally, treatment planning and delivery times were compared to evaluate treatment efficiency. Results: The CIs for 3F-IMRT (0.650±0.05), TH-IMRT (0.643±0.03), and TH-3DCRT (0.631±0.03) were much better than that for 2F-3DCRT (0.318±0.03). The HIs for TH-IMRT (1.053±0.01) and TH-3DCRT (1.055±0.01) were slightly better than those for 2F-3DCRT (1.062±0.01) and 3F-IMRT (1.091±0.007). 2F-3DCRT showed poor CA sparing in terms of the V35, V50, and V63 compared to 3F-IMRT, TH-IMRT, and TH-3DCRT (p<0.05), whereas there was no significant dose difference between 3F-IMRT, TH-IMRT, and TH-3DCRT (p>0.05). The maximum dose to the SP with all plans was below 45 Gy. The treatment planning times for 2F-3DCRT (5.9±0.66 min) and TH-3DCRT (7.32±0.94 min) were much lower than those for 3F-IMRT (45.51±2.76 min) and TH-IMRT (35.58±4.41 min), whereas the delivery times with all plans was below 3 minutes. Conclusion: TH-3DCRT showed excellent carotid sparing capability, comparable to that with TH-IMRT, with high treatment efficiency and short planning and treatment times, comparable to those for 2F-3DCRT, while maintaining good PTV coverage. This work was supported by the Technology Innovation Program, 10040362, Development of an integrated management solution for radiation therapy funded by the Ministry of Knowledge Economy (MKE, Korea).

Organization communication regarding ISO 26000 practices in South Korea: focusing on the enlarged scope

ISO 26000, issued on November 1, 2010, has enlarged the scope of social responsibility (SR) from corporations to all types of organizations. This article examines how organizations that traditionally have not been concerned with this term, such as public or governmental institutions and nonprofit organizations, interpret this new standard and the notion of SR, especially in the South Korean context. For this research, we observed the SR-related reports and media activity of seven Korean organizations: Korean Standards Association (KSA), the Ministry of Knowledge Economy (MKE), Gangdong-gu Office (GDG), Christian Ethics Movement of Korea (CEMK), LG Electronics Union (LGEU), Collective Action (CA), and Working Together Corporation (WTCO). We also carried out interviews with experts in these organizations, who largely work on the subject. Using the organizing theory frame (enactment–selection–retention) of Karl E. Weick, we analyzed three elements of the organizational communication of these institutions: strategy, ISO 26000 messaging, and receivers of the information. ISO 26000 was first actively used in public organizations (e.g., KSA, MKE, and GDG) as a policy tool to expand the concept to all aspects of Korean society, and was later used in certain nonprofit organizations (e.g., LGEU and CEMK) as a new paradigm, creating new concepts such as union SR and churches’ SR that partially accept the international standard in different contexts. Some civil societies, such as CA and WTCO, observe the phenomenon in a passive way to see if it could promote the social values of their organizations. Lastly, in spite of the scope enlargement, we note that SR is still in the range of corporate SR, and the application process in South Korea shows that the social aspect is more easily ignored than the economic and environmental aspects.

Oxygen Reduction Properties of La0.1Sr0.9Co0.8Fe0.2O3-δ Cathode for SOFC Using Electrochemical Method

In recent years, the environmental friendly solid oxide fuel cell (SOFC) has been considered as one of the most efficient power generation systems. During the SOFC operation, the over potential is mainly given by the cathodic oxygen reduction reaction. In this respect, the mechanism of oxygen reduction on the Electrode is important to reveal. Specially, employing ac-impedance spectroscopy which provides an exceptionally is powerful tool for separating the dynamics of several electrode processes with different relaxation times. The present work considers the oxygen reduction reaction on the porous mixed conducting La0.1Sr0.9Co0.8Fe0.2O3-δ (LSCF1982) electrode by using ac-impedance spectroscopy. Firstly, to attain a mixed conducting state of LSCF1982, the ac-impedance spectra measured at various temperatures and oxygen partial pressures were quantitatively analyses by employing the theoretical impedance model developed for oxygen reduction on the mixed conducting electrode.All the measured impedance spectra simply consisted of two depressed arcs which overlapped slightly over the whole T and pO2 ranges. The analysis of the ac-impedance spectra by employing discrete Fourier relaxation transformation (DFRT) allowed us to successfully differentiate the individual reaction steps. This indicates that the overall cathode reaction proceeds by the following two processes: charge transfer reaction and subsequent migration of oxygen vacancy.It is also shown, that the magnitude of the high frequency arc decreased significantly with increasing T, but it remained nearly constant regardless of pO2: In contrast, the low-frequency arc remained almost unchanged in magnitude irrespective of the value of T, while it was highly dependent on the value of pO2. From the experimental results that it is thus deduced that the high frequency arc is attributed to the charge transfer reaction at the TPBs, and the low-frequency arc is associated with diffusion of adsorbed oxygen atom along the electrode/gas interface.Figure 1 shows the steady-state current of the oxide anodes as a function of the electrode potential and aO,int.According to Wang and Nowick [1], the rate determining step determined to exchange current density value as a function of both temperature and oxygen partial pressure.i0 ∝pO2 n The n - value in a relation gives information about the type of species involved in the electrode reaction. The n values have 1 if the rate limiting step is diffusional process of molecular oxygen, 1/2 for dissociative adsorption and 1/4 for charge transfer process depending on the conditions for Langmuir adsorption isotherm.In this study for LSCF1982, the slopes of current exchange density were turned out to be 1/4 at 550 to 650oC. This indicated that the rate limiting step for the electrochemical oxygen reduction in this temperature range is the charge transfer process.In the present work, the oxygen reduction reaction on the porous LSCF1982 electrode was examined by means of analysis of the ac-impedance spectra and DC polarization. In addition, we’ll discuss the other technic like cathodic potentiostatic current transients and Gerisher impedance modeling.Reference[1] Da. Yu. Wang and A. S. Nowick, J. Electochem. Soc., 126, 1155 (1979) Acknowledgement This work was supported by Solid Oxide Fuel Cell of New & Renewable Energy R&D Program (20123010030010) under the Korea Ministry of Knowledge Economy (MIKE)

Characterization of nano-scale strained silicon-on-insulator substrates by multi-wavelength high resolution micro-raman and optical reflectance

This work was financially supported by the grant from the Next-generation Substrate technology for high performance semiconductor devices (No. KI00 2083) of the Ministry of Knowledge Economy (MKE) of Korea, the Brain Korea 21 Project in 2012 and the authors would like to thank Dr. Woo-Sik Yoo, Dr. Noriyuki Hasuike and Prof. Hiroshi Harima of Kyoto Institute of Technology for their experimental arrangement and very insightful discussions.

A Popularity-Aware Semantic Overlay for Efficient Peer-to-Peer Search

This research was supported by the MKE(The Ministry of Knowledge Economy), Korea, under the ITRC(Information Technology Research Center) support program (NIPA-2014-H0301-14-1017) supervised by the NIPA(National IT Industry Promotion Agency) and by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(No. 2013R1A1A2009913).