• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.108-108
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• 2011

Organometallic complexes containing unpaired spins, such as metalloporphyrin or metallophthalocyanine, have extensively studied with increasing interests of their promising model systems in spintronic applications. Additionally, the use of these complexes as an acceptor molecule in chemical sensors has recently received great attentions. In this presentation, we have investigated adsorption of nitric oxide (NO) molecules at Co-porphyrin molecules on Au(111) surfaces with scanning tunneling microscopy and spectroscopy at low temperature. At the location of Co atom in Co-porphyrin molecules, we could observe a Kondo resonance state near Fermi energy in density of states (DOS) before exposing NO molecules and the Kondo resonance state was disappeared after NO exposing because the electronic spin structure of Co-porphyrin were modified by forming a cobalt-NO bonding. Furthermore, we could locally control the chemical reaction of NO dissociations from NO-CoTPP by electron injections via STM probe. After dissociation of NO molecules, the Kondo resonance state was recovered in density of state. With a help of density functional theory (DFT) calculations, we could understand that the modified electronic structures for NO-Co-porphyrin could be occurred by metal-ligand hybridization and the dissociation mechanisms of NO can be explained in terms of the resonant tunneling process via molecular orbitals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.6
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• pp.637-645
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• 1991

Physicochemical factors affecting cooking and eating quality of rice and their mechanisms were investigated. The stickiness of cooked rice was negatively correlated with amylose content(r=0.58, p<0.05) and protein content(r=-0.72, p<0.01), but not affected by crude fat content of rice. The ultrastructure of cooked rice grain showed the progressive gelatinization of starch from the periphery toward the center of the endosperm as water and heat energy diffused into. The rate of water diffusion appears to be dependent on the cell arrangement in the endosperm and the protein content of milled rice. Once water and heat reach the starch granules, the rate of in situ gelatinization of starches appears to be dependent on their own gelatinization temperature range and amylose content. Protein acts as a barrier for the swelling of starch and water diffusion in two ways : 1) by encasing starch granules in the starchy endosperm, and 2) by forming a barrier between the subaleurone layer and the starchy endosperm. Therefore, the separation and fragmentation of the outermost layers of the endosperm occurred more easily in the low-protein content rices, and was associated with increases of solids lost in cooking-water at 95$^{\circ}C$ and stickiness of cooked rice.

• Corrosion Science and Technology
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• v.19 no.1
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• pp.8-15
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• 2020

In this paper, the efficiency and the inhibition mechanisms of cobalt salts (cobalt nitrate and cobalt-exchange silica Co/Si) for the corrosion protection of AA2024 were investigated in a neutral aqueous solution by using the electrochemical impedance spectroscopy (EIS) and polarization curves. The experimental measurements suggest that cobalt cation plays a role as a cathodic inhibitor. The efficiency of cobalt cation was important at the concentration range from 0.001 to 0.01 M. The formation of precipitates of oxides/hydroxides of cobalt on the surface at low inhibitor concentration was confirmed by the Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy (SEM/EDS) analysis. EIS measurements were also conducted for the AA2024 surface covered by water-based epoxy coating comprising Co/Si salt. The results obtained from exposure in the electrolyte demonstrated the improvement of the barrier and inhibition properties of the coating exposed in the electrolyte solution for a lengthy time. The SEM/EDS analysis in artificial scribes of the coating after salt spray testing revealed the release of cobalt cations in the coating defect to induce the barrier layer on the exposed AA2024 substrate.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2546-2553
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• 2015

Falling can happen to anyone, anywhere at anytime and especially it is one of the risk factor that can lead causes of death of persons aged 65 and over. Recently, the study of fall detection mechanisms as a smart healthcare service based on the IoT(Internet of Things) are being actively investigated. In this paper, we implement a fall detection system using arduino as a smart sensor communicates with a smart device. When transmitting the information of the acceleration on a sensor smart sensor with a BLE(Bluetooth Low Energy), the smart device processing and analyzing this information. and determines a fall situation. A fall detection system based on the Internet of Things which using smart sensor and smart device, has the advantage of being able to overcome the mobility and portability constraints.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.3
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• pp.251-268
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• 1986

Selecting a site for the safe disposal of radioactive waste requires the evaluation of a wide range of geologic, mineralogic, hydrologic, and physicochemical properties. Although highly diverse, these properties are in fact interrelated. Site requirements are also diverse because they are influenced by the nature of the radionuclides in the waste, for example, their half-lives, specific energy, and chemistry. A fundamental consideration in site selection is the mineralogy of the host rock, and one of the most ubiquitous mineral groups is clay minerals. Clays and clay minerals as in situ lithologic components and engineered barriers may playa significant role in retarding the migration of radionuclides. Their high sorptivity, longevity (stability), low permeability, and other physical factors should make them a very effective retainer of most radionuclides in nuclear wastes. There are, however, some unanswered questions. For example, how will their longevity and physicochemical properties be influenced by such factors as radionuclide concentration, radiation intensity, elevated temperatures, changes in redox condition, pH, and formation fluids for extended periods of time? Understanding of mechanisms affecting clay mineral-radionuclide interactions under prevailing geochemical conditions is important; however, the utilization of experimental geochemical information related to physicochemical properties of clays and clay-bearing materials with geohydrologic models presents a uniquely challenging problem in that many assessments have to be based on model predictions rather than on experiments. These are high-priority research investigations that need to be addressed before complete reliance for disposal area performance is made on clays and clay minerals.

• Advances in Computational Design
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• v.7 no.3
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• pp.189-210
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• 2022

Deployable structures have the ability to shift from a compact state to an expanded functional configuration. By extension, reconfigurability is another function that relies on embedded computation and actuators. Linkage-based mechanisms constitute promising systems in the development of deployable and reconfigurable structures with high flexibility and controllability. The present paper investigates the deployment and reconfigurability of modular linkage structures with a pin and a sliding support, the latter connected to a linear motion actuator. An appropriate control sequence consists of stepwise reconfigurations that involve the selective releasing of one intermediate joint in each closed-loop linkage, effectively reducing it to a 1-DOF "effective crank-slider" mechanism. This approach enables low self-weight and reduced energy consumption. A kinematics and finite-element analysis of different linkage systems, in all intermediate reconfiguration steps of a sequence, have been conducted for different lengths and geometrical characteristics of the members, as well as different actuation methods, i.e., direct and cable-driven actuation. The study provides insight into the impact of various structural typological and geometrical factors on the systems' behavior.

• Tribology and Lubricants
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• v.37 no.6
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• pp.213-223
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• 2021

Electrochemical mechanical planarization (ECMP) was developed to overcome the shortcomings of conventional chemical mechanical planarization (CMP). Because ECMP technology utilizes electrochemical reactions, it can have a higher efficiency than CMP even under low pressure conditions. Therefore, there is an advantage in that it is possible to reduce dicing and erosions, which are physical defects in semiconductor CMP. This paper summarizes the papers on ECMP published from 2003 to 2021 and analyzes research trends in ECMP technology. First, the material removal mechanisms and the configuration of the ECMP machine are dealt with, and then ECMP research trends are reviewed. For ECMP research trends, electrolyte, processing variables and pads, tribology, modeling, and application studies are investigated. In the past, research on ECMP was focused on basic research for the development of electrolytes, but it has recently developed into research on tribology and process variables and on new processing systems and applications. However, there is still a need to increase the processing efficiency, and to this end, the development of a hybrid ECMP processing method using another energy source is required. In addition, ECMP systems that can respond to the developing metal 3D printing technology must be researched, and ECMP equipment technology using CNC and robot technology must be developed.

• Korean Circulation Journal
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• v.53 no.5
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• pp.273-293
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• 2023

Pulsed field ablation (PFA) was recently rediscovered as an emerging treatment modality for the ablation of cardiac arrhythmias. Ultra-short high voltage pulses are leading to irreversible electroporation of cardiac cells subsequently resulting in cell death. Current literature of PFA for pulmonary vein isolation (PVI) consistently reported excellent acute and long-term efficacy along with a very low adverse event rate. The undeniable benefit of the novel ablation technique is that cardiac cells are more susceptible to electrical fields whereas surrounding structures such as the pulmonary veins, the phrenic nerve or the esophagus are not, or if at all, minimally affected, which results in a favorable safety profile that is expected to be superior to the current standard of care without compromising efficacy. Nevertheless, the exact mechanisms of electroporation are not yet entirely understood on a cellular basis and pulsed electrical field protocols of different manufactures are not comparable among one another and require their own validation for each indication. Importantly, randomized controlled trials and comparative data to current standard of care modalities, such as radiofrequency- or cryoballoon ablation, are still missing. This review focuses on the "pearls" and "pitfalls" of PFA, a technology that has the potential to become the future leading energy source for PVI and beyond.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.76-83
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• 1998

The most remarkable aspect in the hormesis law is that dose of harmful agents can produce effect that are diametrically opposite to the effect found with high doses of the same agent. Minute quantities of a harmful agent bring about very small change in the organism and control mechanisms appear to subjugate normal processes to place the organism in a state of albert and repair. The stimulated organism in more responsive to changes in environmental factors than it did before being alerted. Routine functions, including repair and defense, have priority for available energy and matetial. The alerted organism utilizes nutrients more efficiently, grows faster, shows improved defense, and lives longer. Accelerated germination, sprouting, growth, development, blooming and ripening, and increased crop yield and resistance to disease are found in plants. Another concept supported by the data in that low doses of ionizing radiation provide increased resistance to subsequent high doses of radiation. The hormesis varies with subject plant, variety, state of seed, environmental and cultural conditions, physiologic function measured, dose rate and total exposure. The results of hormesis are less consistently found, probably due to the great number of uncontrolled variables in the experiments. The general dosage for radiation homlesis in about 100 (10 to 1,000) times ambient or 100 (10 to 1,000) times less than a definitely harmful dose, but these must be modified to the occasion. Although little is known about most mechanisms of homzesis reaction, overcompensation of repair mechanism is offered as one mechanism.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.123-133
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• 2013

Green infrastructure projects have the potential to reduce global warming and deliver sustainable energy solutions. Recently, the construction industry has been expanding their portfolios in New and Renewable (NRE) projects. However, the economic feasibility of NRE projects have not been validated and construction companies are not acquainted with their associated risks. This research performed a two-tiered feasibility study of the domestic projects registered for CDM in the UNFCCC. The first phase involved calculating the average IRR and NPV of the domestic CDM projects, which showed that their profitability to be very low. In the second phase, four NRE projects (Solar, Wind, Hydro, Landfill Gas) were selected and additional income generated from Feed-in-Tariff and CER sales were added to determine the improvements in the projects' IRR and NPV. Results indicate that Solar and Landfill Gas projects benefited the most from the two support mechanisms, while benefits to Wind and Hydro projects were minimal. While the Landfill Gas project had the highest IRR, the Wind project was the most investment attractive due to its NPV and minimal dependency on FiT and CER sales. Construction companies should enter into NRE projects with a long term view as related technologies mature.