• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.229-229
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• 2010

With the scaling down of ultra large integrated circuits (ULSI) to the sub-50 nm technology node, the need for an ultra-thin, continuous and conformal diffusion barrier and Cu seed layer is increasing. However, diffusion barrier and Cu seed layer formation with a physical vapor deposition (PVD) method has become difficult as the technology node is reduced to 30 nm and beyond. Recent work on self-forming barrier processes using PVD Cu alloys have attracted great attention due to the capability of conformal ultra-thin barrier formation using a simple technique. However, as in the case of the conventional barrier and Cu seed layer, PVD of the Cu alloy seed layer will eventually encounter the difficulty in conformal deposition in narrow line trenches and via holes. Atomic layer deposition (ALD) has been known for its good step coverage and precise thickness control, and is a candidate technique for the formation of a thin conformal barrier layer and Cu seed layer. Conformal Cu-Mn seed layers were deposited by plasma enhanced atomic layer deposition (PEALD) at low temperature ($120^{\circ}C$), and the Mn content in the Cu-Mn alloys were controlled form 0 to approximately 10 atomic percent with various Mn precursor feeding times. Resistivity of the Cu-Mn alloy films decreased by annealing due to out-diffusion of Mn atoms. Out-diffused Mn atoms were segregated to the surface of the film and interface between a Cu-Mn alloy and $SiO_2$, resulting in self-formed $MnO_x$ and $MnSi_xO_y$, respectively. No inter-diffusion was observed between Cu and $SiO_2$ after annealing at $500^{\circ}C$ for 12 h, indicating an excellent diffusion barrier property of the $MnSi_xO_y$. The adhesion between Cu and $SiO_2$ was enhanced by the formation of $MnSi_xO_y$. Continuous and conductive Cu-Mn seed layers were deposited with PEALD into 32 nm $SiO_2$ trench, enabling a low temperature process, and the trench was perfectly filled using electrochemical plating (ECD) under conventional conditions. Thus, it is the resultant self-forming barrier process with PEALD Cu-Mn alloy film as a seed layer for plating Cu that has further potential to meet the requirement of the smaller than 30 nm node.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1240-1244
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• 1999

In order to assess the effects on the magnetic properties due to the defect in the material irradiated by fast neutron ranging $10^0-10^{18}n/cm^2$, the magnetic properties such as maximum magnetic induction, coercivity, remanence, Barkhausen Noise Amplitude(BNA), Barkhausen Noise Energy(BNE) and hardness were measured. It is shown that the magnetic properties and hardness do not change by the fast neutron irradiation under $10^{17}n/cm^2$. Therefore, in this experiment, it is understood that the magnetic properties decrease by the increase of hardness. This measurement method can be used to evaluate the neutron irradiation embrittlement nondestructively since the magnetic properties and hardness do change by the neutron irradiation over $10^{17}n/cm^2$ consistently.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.654-660
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• 1998

In preparing PSZT powder by hydrothermal synthesis, effects of reaction temperature, concentration of raw materials and mineralizer on crystallinity, particle size distribution, and dielectric constant were investigated. By varying the concentration of mineralizer and the ratio of Pb to Sr or Zr to Ti, crystalline PSZT powder, having the mean particle size of $0.3{\sim}15{\mu}m$, was prepared by hydrothermal synthesis in the temperature range of $120{\sim}200^{\circ}C$ for a 2h reaction. PSZT ceramics, having dielectric constant of 1000~3000, were prepared at $1150^{\circ}C$ for a 2h sintering reaction of the PSZT powders. Experimental results showed that the weight mean particle size of $0.5{\mu}m$ was obtained when the concentration of KOH in the solution was 10 wt % and the ratio of Pb to Sr was 0.95/0.05, that of Zr to Ti was 0.52/0.48. It also showed that the ceramics of dielectric constant of 2900 were prepared through sintering of this PSZT powder. Size of PSZT particles became smaller with its narrow distribution as the concentration of KOH increased up to 10 wt %. However, it came to be larger at this concentration and above. By adding small amount of Sr that would not affect that crystallinity of particles we can improve dielectric property of sintered materials. Addition of Zr may shift the major crystal phase of synthetic PSZT powder from tetragonal to rhombohedral phase.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.243-254
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• 2019

In this study, problems of the waterproofing methods in which water leakage occurs in the upper slab of the underground parking lot of apartment houses and the requirements considering the characteristics of the upper slab, and selected the appropriate performance(proposal) for the composite polyurea process are reviewed. As a result of the study, it is necessary to review performance such as responsiveness to upper slab of the multi-unit underground parking lot that is comprised of (1) crack and behavior responsiveness, (2) surface integrity, (3) vertical watertight stability, (4) pressure layer construction, (5) impact and pressure response and (6) vehicle moving load. As a result of evaluating 5 items corresponding to the requirements for the soft and hard complex polyurea, all of them were found to meet the conditions, and each materials were improved by compounding the materials that had problems when applying a single-ply method, thereby clarifying the advantages and disadvantages of the material property. However, in order to apply to the actual site, additional evaluation on site applicability such as mock-up evaluation should be conducted, and subsequent studies on the applicability of the market through review of economic feasibility and maintenance is required.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.253-258
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• 2019

Several materials are used to design the sorbents applied in a fast-fluidized bed process for post-combustion $CO_2$ capture. In this study, $K_2CO_3$-based dry sorbent (KMC) was prepared by using Micro-cell C (MCC), one of the materials used to design the sorbent, and then its $CO_2$ sorption and regeneration properties were evaluated. KMC sorbent showed a low $CO_2$ capture capacity of 21.6 mg $CO_2/g$ sorbent, which is about 22% of the theoretical value (95.4 mg $CO_2/g$ sorbent) even at 1 cycle, and showed a low $CO_2$ capture capacity of 13.7 mg $CO_2/g$ sorbent at 5 cycles. It was confirmed that the KMC sorbent was deactivated due to the formation of a $K_2Ca$ $(CO_3)_2$ phase, resulting from the reaction of the $K_2CO_3$ with the Ca component contained in the MCC. In order to solve the deactivation of sorbent, and KM8 sorbent was prepared by adding the process of calcining the MCC at $850^{\circ}C$. The KM8 sorbent showed a high $CO_2$ capture capacity of 95.2 mg $CO_2/g$ sorbent and excellent regeneration property. Thus, it was confirmed that the deactivation of the sorbent could be solved by adding the calcining step to remove the side reaction causing material.

• Applied Chemistry for Engineering
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• v.30 no.4
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• pp.460-465
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• 2019

In this study, the optimization of active materials and the preparation of particulate adsorbents for the application of metal oxide-based adsorbents for the treatment of $H_2S$, an air pollutant and odorant, occurred in various industrial facilities were investigated. The adsorbents were prepared by using $TiO_2$, which has a high physicochemical stability and relatively high specific surface area among metal oxides and also by different kinds and contents of active materials. The correlation between the physicochemical property and adsorption performance of the adsorbents confirmed that the adsorbent containing KI, which is a typical alkali metal among the active metals, showed the highest adsorption performance. The relationship between the contents and the adsorption performance was non-proportional, but a volcano plot. From XRD, SEM and BET analyses, it was confirmed that the active material was exposed to the surface above a certain amount and also the adsorption performance was the best when the specific surface area and pore volume were $40{\sim}100m^2/g$ and $0.1{\sim}0.3cm^3/g$, respectively. For practical application, the adsorbent was granulated or coated on a ceramic support. It was also confirmed that the adsorbent showed high adsorption performance when the adsorbent was coated on the ceramic rather than that of the granulated support.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.200-207
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• 2019

Cement is one of the most commonly used materials in the construction and civil engineering industry. However, emissions of carbon dioxide generated during the production of cement have been linked to climate change and environment pollutants. In order to replace cement, many studies have been actively performed research to utilizing Blast Furnace Slag(BFS), which is a byproduct of the steel industry. This study aims to investigate the physiochemical properties of the BFS powder based grout to determine whether it can be used as an environment-friendly grout material. As a fine powder, BSF can be used instead of cement grout due to its potential hydraulic property. BSF has also been known for its ability to strengthen materials long-term and to densify the internal structure of concrete. In order to investigate the physicochemical properties of the BFS powder based grout as a grout material, in this study assessment tests were performed through a gel-time measurement, uniaxial compressive strength, and chemical resistance tests, and heavy-metal leaching test. Characteristics and advantages of the slag were studied by comparing slag and cement in various methods.

• Korean Journal of Heritage: History & Science
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• v.39
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• pp.131-163
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• 2006

Interest in Korean cultural properties has rising in recent years, not only on the part of existing researcher and scholars but also among the general public. The scope of interest has expand also, no longer being confined to Korea, and has given rise to movements for redemption of cultural properties preserved overseas and plans on how to make use of information about them. Aside from the basic idea that all cultural properties overseas are subjects for redemption, this paper argues that it is time to seek ways to actively make use of information on those cultural properties, and that this must be preceded by dear understanding of the current status through systematic on-site research and investigation of the channels through which they left the country. In addition, it is necessary to look at the issue with a broader perspective. The cultural properties in question must be regarded not as the sole property of Korea, the country that produced them, but as artworks of the world with outstanding universal value, to be protected and utilized by all human beings. From this point of view, this paper organize studies the kinds of Korean cultural properties kept at three major museums in the United Stated, including the Museum of Fine Arts, Roston, and traces the routes and methods by which they were taken out of Korea. Based on the perception of Korean artworks overseas as explained above, the purpose of this paper is to examine materials those cultural properties not only for academic research, but also todistinguish between those properties that should be redeemed and those that should be publicized overseas by clarifying how they were taken overseas, and thus provide basic materials for policy purposes.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.5
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• pp.187-191
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• 2019

Perovskite-type oxides have consistently attracted considerable attention for their applications in high-temperature electrochemical devices, such as electrolytes and electrodes of solid oxide fuel cells, oxygen permeating membranes and sensors etc. Among them, the electrical conductivity of 10 % Sr and 10 % Mg doped $LaAlO_3$ (LSAM9191) was measured using impedance spectroscopy and 4-probe d.c. method. Below $550^{\circ}C$, the grain boundary resistance mostly determined the overall conductivity; however, it nearly disappeared above $800^{\circ}C$. Using the defect model and curve fitting, the ionic and electronic conductivity contributions were also separated. In the temperature region where the sample resistance is mostly determined by the grain volume property, LSAM9191 was an oxygen ion conductor at low $Po_2$ and a mixed conductor at high $Po_2$. With increasing temperature, the ionic conduction region only slightly increased. Thus, LSAM9191 is a promising material as an oxygen ion conductor at high temperature and in low $Po_2$.

• Journal of Adhesion and Interface
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• v.20 no.1
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• pp.23-28
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• 2019

In this study, the micro- and nano-particles were used and their shapes were transferred into the polydimethylsiloxane (PDMS) film to fabricate the dry adhesives and their properties were investigated. The Cu nanoparticles of the sizes of 20 nm, 40 nm and 70 nm and the polymethylmethacrylate (PMMA) beads of the size of $5{\mu}m$ were used to transfer their images and the resultant properties of the dry adhesives were compared. The effects of particle size and materials on the mechanical property, tensile adhesion strength, light transmittance, surface morphology, water contact angle were studied. The dry adhesives obtained from the transfer process of Cu nanoparticles with the size of 20 nm resulted in the enhancement of tensile adhesion strength more than 300% compared to that of the bare PDMS. The formation of nanostructure of large surface area on the surface of the PDMS film by the Cu nanoparticles may responsible for the improvement. This study suggests that the use of nanoparticles during the fabrication of PDMS dry adhesives is easy and effective and could be applied to the fabrication of the medical patch.