• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.73-73
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• 2012

Modern technology-driven society largely relies on hybrid electric vehicles or electric vehicles for eco-friendly transportation and the use of high technology devices. Lithium rechargeable batteries are the most promising power sources because of its high energy density but still have a challenge. Graphite is the most widely used anode material in the field of lithium rechargeable batteries due to its many advantages such as good cyclic performances, and high charge/discharge efficiency in the initial cycle. However, it has an important safety issue associated with the dendritic lithium growth on the anode surface at high charging current because the conventional graphite approaches almost 0 V vs $Li/Li^+$ at the end of lithium insertion. Therefore, a fundamental solution is to use an electrochemical redox couple with higher equilibrium potentials, which suppresses lithium metal formation on the anode surface. Among the candidates, $Li_4Ti_5O_{12}$ is a very interesting intercalation compound with safe operation, high rate capability, no volume change, and excellent cycleability. But the insulating character of $Li_4Ti_5O_{12}$ has raised concerns about its electrochemical performance. The initial insulating character associated with Ti4+ in $Li_4Ti_5O_{12}$ limits the electronic transfer between particles and to the external circuit, thereby worsening its high rate performance. In order to overcome these weak points, several alternative synthetic methods are highly required. Hence, in this presentation, novel ways using a synergetic strategy based on 1D architecture and surface coating will be introduced to enhance the kinetic property of Ti-based electrode. In addition, first-principle calculation will prove its significance to design Ti-based electrode for the most optimized electrochemical performance.

• Journal of Korean Society of Archives and Records Management
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• v.17 no.3
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• pp.49-70
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• 2017

This study, as the basic research for making research records management policies, aims to define research records and analyze the value and characteristics of research records from an archives and records management perspective. For these purposes, this study defines research records and their types by reviewing related studies. In addition, this study analyzed the following research records values: (1) evidence of research integrity and accountability with regard to research misconduct; (2) information for a succeeding study and an honorable failure; and (3) an asset for intellectual property rights and technology transfer. Finally, this study extracted the following characteristics of the research records: (1) each type of documents, data, and materials; (2) the archival bond between program and records; and (3) the continuity of production and use of the records. The findings from this analysis could be considered in revising related laws and policies.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.1 s.34
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• pp.9-16
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• 2005

This paper presents the development of new anisotropic conductive adhesives with enhanced thermal conductivity for the wide use of adhesive flip chip technology with improved reliability under high current density condition. The continuing downscaling of structural profiles and increase in inter-connection density in flip chip packaging using ACAs has given rise to reliability problem under high current density. In detail, as the bump size is reduced, the current density through bump is also increased. This increased current density also causes new failure mechanism such as interface degradation due to inter-metallic compound formation and adhesive swelling due to high current stressing, especially in high current density interconnection, in which high junction temperature enhances such failure mechanism. Therefore, it is necessary for the ACA to become thermal transfer medium to improve the lifetime of ACA flip chip joint under high current stressing condition. We developed thermally conductive ACA of 0.63 W/m$\cdot$K thermal conductivity using the formulation incorporating $5 {\mu}m$ Ni and $0.2{\mu}m$ SiC-filled epoxy-bated binder system to achieve acceptable viscosity, curing property, and other thermo-mechanical properties such as low CTE and high modulus. The current carrying capability of ACA flip chip joints was improved up to 6.7 A by use of thermally conductive ACA compared to conventional ACA. Electrical reliability of thermally conductive ACA flip chip joint under current stressing condition was also improved showing stable electrical conductivity of flip chip joints. The high current carrying capability and improved electrical reliability of thermally conductive ACA flip chip joint under current stressing test is mainly due to the effective heat dissipation by thermally conductive adhesive around Au stud bumps/ACA/PCB pads structure.

• Journal of Korea Technology Innovation Society
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• v.11 no.4
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• pp.532-562
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• 2008

Recently, one of the issues to be discussed from the viewpoint of product management in National R&D Programs is about the management of intellectual property produced by joint research and development. According to existing legislative system, the main R&D institute and collaborative enterprise own the patent produced by joint R&D activities together at the rate of investment. But, there are many discussions if that is right in legal principles and in substance. Patents by Cooperative National R&D Programs are very different from common patents because of its characteristics and have scheme controlled complexly by related laws and ordinances. This paper aims to review the legal theory on the possession and utilization of patents produced by Cooperative National R&D Programs, and to try to find out the improvement of existing legislative system. For this purpose, after looking into the meaning and the legal system of Cooperative National R&D Programs, and examining the ruling theory on the possession and utilization of co-invented patent, finally research the problems and improvement of existing related legislative system.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.278.1-278.1
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• 2014

Organic materials have been explored as the gate dielectric layers in thin film transistors (TFTs) of backplane devices for flexible display because of their inherent mechanical flexibility. However, those materials possess some disadvantages like low dielectric constant and thermal resistance, which might lead to high power consumption and instability. On the other hand, inorganic gate dielectrics show high dielectric constant despite their brittle property. In order to maintain advantages of both materials, it is essential to develop the alternative materials. In this work, we manufactured nanocomposite gate dielectrics composed of organic material and inorganic nanoparticle and integrated them into organic TFTs. For synthesis of nanocomposite gate dielectrics, polyimide (PI) was explored as the organic materials due to its superior thermal stability. Candidate nanoprticles (NPs) of halfnium oxide, titanium oxide and aluminium oxide were considered. In order to realize NP concentration dependent electrical characteristics, furthermore, we have synthesized the different types of nanocomposite gate dielectrics with varying ratio of each inorganic NPs. To analyze gate dielectric properties like the capacitance, metal-Insulator-metal (MIM) structures were prepared together with organic TFTs. The output and transfer characteristics of organic TFTs were monitored by using the semiconductor parameter analyzer (HP4145B), and capacitance and leakage current of MIM structures were measured by the LCR meter (B1500, Agilent). Effects of mechanical cyclic bending of 200,000 times and thermally heating at $400^{\circ}C$ for 1 hour were investigated to analyze mechanical and thermal stability of nanocomposite gate dielectrics. The results will be discussed in detail.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.62-69
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• 2022

Graphene has a large surface area to volume ratio and good mechanical and electrical property and biocompatibility. This study described the electrochemical deposition and reduction of graphene oxide on the surface of indium tin oxide (ITO) glass slide and electrochemical characterization of graphen-modified ITO. Cyclic voltammetry was used for the deposition and reduction of graphene oxide. The surface of graphen-coated ITO was characterized using scanning electron microscopy and energy dispesive X-ray spectroscopy. The electrodes were evaluated by performing cyclic voltammetry and electrochemical impedance spectroscopy. The number of cycles and scan rate greatly influenced on the coverage and the degree of reduction of graphene oxide, thus affecting the electrochemical properties of electrodes. Modification of ITO with graphene generated higher current with lower charge transfer resistance at the electrode-electrolyte interface. Glucose oxidase was immobilized on the graphene-modified ITO and has been found to successfully generate electrons by oxidizing glucose.

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.328-333
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• 1998

Lattice-matched InAIAs epilayers were grown on (001) InP substrate by low pressure metalorganic chemical vapor deposition. The effects of growth conditions on the properties of InAIAs were analyzed, and InGaAs/InAIAs single and multiple quantum wells were successfully grown. It was observed that the optical property of InAIAs epilayers was improved in the temperature range of 620~$700^{\circ}C$ as the growth temperature increased due to the reduction of oxygen incorporation, however, the crystallinity decreased at temperatures higher than $750^{\circ}C$ due to the degraded crystallinity of the bufter layers. The enhanced incorporation of AI into epilayer was observed at high $AsH_3$flow rates and it was explained in terms of the differences in bond strengths of AI-As and In-As. The measured photoluminescence peak energies from InGaAs/InAIAs single quantum wells were consistent with the calculated ones based on transfer matrix method. High-order satellite peaks and fine thickness fringes were observed by high-resolution x-ray diffraction, implying that the high-quality multiple quantum wells with abrupt heterointerfaces were grown.

• Progress in Superconductivity and Cryogenics
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• v.20 no.4
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• pp.11-15
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• 2018

Torque tubes in High Temperature Superconducting (HTS) motor transfer torque from superconducting field winding rotor to the room temperature shaft. It should have minimum heat conduction property for minimizing the load on cryo-refrigerator. Generally, these torque tubes are made with stainless steel material because of high strength, very low outgassing and low thermal contraction properties at cryogenic temperatures and vacuum conditions. With recent developments in composite materials, these torque tubes could be made of composites such as Kevlar and S-Glass, which have the required properties like high strength and low thermal conductivity at cryogenic temperatures, but with a reduced weight. Development and testing of torque tubes made of these composites for HTS motor are taken up at Bharat Heavy Electricals Limited (BHEL), Hyderabad in collaboration with Central Institute of Plastics and Engineering Technology (CIPET), Chennai and Indian Institute of Technology (IIT), Kharagpur. As these materials are subjected to vacuum, it is important to measure their outgassing rates under vacuum conditions before manufacturing prototype torque tubes. The present study focusses on the outgassing characteristics of Kevlar and S-Glass, using an Outgassing Measurement System (OMS), developed at IIT Kharagpur. The OMS facility works under vacuum environment, in which the test samples are exposed to vacuum conditions over a sufficient period of time. The outgassing measurements for the composite samples were obtained using pressure-rise technique. These studies are useful to quantify the outgassing rate of composite materials under vacuum conditions and to suggest them for manufacturing composite torque tubes used in HTS motors.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.247-253
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• 2010

The demand that needs 'Digital Legacy', a notion that an Internet user can transfer his private blogs, e-mail and financial assets to inheritors and party interested when he died suddenly in the accident, has been growing recently. This issue has become a social hot potato since Justine Ellsworth's father in USA sued Yahoo for the right to access his son's Yahoo e-mail account after Justine Ellsworth had died in Iraq, in November, 2004 and the problems happened to deal with suicide-related blogs and homepages when great entertainers in Korea committed suicide and soldiers' parents in the situation of warship Chonan tragedy in Korea demanded access to soldiers' homepages and e-mail accounts. The point at issue focuses on the property matters about the digital information of the deceased and the relationship between the deceased and the Internet Service Provider(ISP). This research looks into the trend of judicial precedents and laws related to the digital information of the deceased and suggests the preliminary data of the next research.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.224-224
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• 2012

For decades, carbon fiber has expanded their application fields from reinforced composites to energy storage and transfer technologies such as electrodes for super-capacitors and lithium ion batteries and gas diffusion layers for proton exchange membrane fuel cell. Especially in fuel cell, water repellency of gas diffusion layer has become very important property for preventing flooding which is induced by condensed water could damage the fuel cell performance. In this work, we fabricated superhydrophobic network of carbon fiber with high aspect ratio hair-like nanostructure by preferential oxygen plasma etching. Superhydrophobic carbon fiber surfaces were achieved by hydrophobic material coating with a siloxane-based hydrocarbon film, which increased the water contact angle from $147^{\circ}$ to $163^{\circ}$ and decreased the contact angle hysteresis from $71^{\circ}$ to below $5^{\circ}$, sufficient to cause droplet roll-off from the surface in millimeter scale water droplet deposition test. Also, we have explored that the condensation behavior (nucleation and growth) of water droplet on the superhydrophobic carbon fiber were significantly retarded due to the high-aspect-ratio nanostructures under super-saturated vapor conditions. It is implied that superhydrophobic carbon fiber can provide a passage for vapor or gas flow in wet environments such as a gas diffusion layer requiring the effective water removal in the operation of proton exchange membrane fuel cell. Moreover, such nanostructuring of carbon-based materials can be extended to carbon fiber, carbon black or carbon films for applications as a cathode in lithium batteries or carbon fiber composites.