• 한국자기공명학회:학술대회논문집
• /
• 한국자기공명학회 2002년도 International Symposium on Magnetic Resonance
• /
• pp.72-72
• /
• 2002

In most traditional sorption study in environmental conditions, experimental sorption data have been measured and interpreted by empirical ways such as partition coefficient and sorption isotherms. A mechanistic understanding of heavy metal interactions with various minerals (metal oxides, clay minerals) in aqueous medium is required to describe the behavior of radioactive metal ions in the environment. Various spectroscopic methods provide direct or indirect information on sorption mechanisms involved. We applied EPR (Electron Paramagnetic Resonance) spectroscopy to investigate the nature of metal ion sorption at water/mineral interfaces using Cu(II) as a spin probe. The major sorbed species and their motional state was identified by their EPR spectra. They showed distinct signals due to their strength of binding, local structure and motional state. The EPR results together with macroscopic sorption data show that sorption involved at least three different mechanisms depending on chemical environments (1).

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.98.2-98.2
• /
• 2013

Electrochemical phenomena underpin a broad spectrum of energy, chemical, and information technologies such as resistive memories and secondary batteries. The optimization of functionalities in these devices requires understanding electrochemical mechanisms on the nanoscale. Even though the nanoscale electrochemical phenomena have been studied by electron microscopies, these methods are limited for analyzing dynamic electrochemical behavior and there is still lack of information on the nanoscale electrochemical mechanisms. The alternative way can be an atomic force microscopy (AFM) because AFM allows nanoscale measurements and, furthermore, electrochemical reaction can be controlled by an application of electric field through AFM tip. Here, I will summarize recent studies to probe nanoscale electrochemical reaction in battery applications by AFM. In particular, we have recently developed electromechanical based AFM techniques for exploring reversible and irreversible electrochemical phenomena on the nanoscale. The present work suggests new strategies to explore fundamental electrochemical mechanisms using the AFM approach and eventually will provide a powerful paradigm for probing spatially resolved electrochemical information for energy applications.

• Biomolecules & Therapeutics
• /
• 제20권3호
• /
• pp.268-272
• /
• 2012

Nephrotoxicity occurs when kidney-specific detoxification and excretion do not work properly due to the damage or destruction of kidney function by exogenous or endogenous toxicants. Exposure to drugs often results in toxicity in kidney which represents the major control system maintaining homeostasis of body and thus is especially susceptible to xenobiotics. Understanding the toxic mechanisms for nephrotoxicity provides useful information on the development of drugs with therapeutic benefits with reduced side effects. Mechanisms for drug-induced nephrotoxicity include changes in glomerular hemodynamics, tubular cell toxicity, inflammation, crystal nephropathy, rhabdomyolysis, and thrombotic microangiopathy. Biomarkers have been identified for the assessment of nephrotoxicity. The discovery and development of novel biomarkers that can diagnose kidney damage earlier and more accurately are needed for effective prevention of drug-induced nephrotoxicity. Although some of them fail to confer specificity and sensitivity, several promising candidates of biomarkers were recently proved for assessment of nephrotoxicity. In this review, we summarize mechanisms of drug-induced nephrotoxicity and present the list of drugs that cause nephrotoxicity and biomarkers that can be used for early assessment of nephrotoxicity.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 추계학술대회 논문집
• /
• pp.581-584
• /
• 2005

Ion beam processing is one of the key technologies to realize mastless and resistless sub 50nm nano fabrication. Unwanted effects, however, may occur since an energetic ion can interact with a target surface in various ways. Depending on the ion energy, the interaction can be swelling, deposition, sputtering, re-deposition, implantation, damage, backscattering and nuclear reaction. Sputtering is the fundamental mechanisms in ion beam induced direct patterning. Re-deposition and backscattering are unwanted mechanisms to avoid. Therefore understanding of ion beam-solid interaction should be advanced for further ion beam related research. In this paper we simulate some important interaction mechanisms between energetic incident ions and solid surfaces and the results are compared with experimental data. The simulation results are agreed well with experimental data.

• Structural Engineering and Mechanics
• /
• 제13권2호
• /
• pp.171-186
• /
• 2002

Static and dynamic penetration tests of reinforced concrete (RC) slab specimens are described and discussed. The experimental study was aimed at a better understanding of mechanisms that are involved in dynamic penetration, through their identification in static tests, and by establishing their relative influence in similar dynamic cases. The RC specimens were $80{\times}80-cm$ square plates, and they were made of 30 MPa concrete. The non-deforming steel penetrator was a 50-mm diameter steel rod with a conical nose of 1.5 aspect ratio. Impact penetration tests were carried out with an air gun, which launched the projectiles at velocities of up to 300 m/sec. The static tests were conducted using a closed loop displacement control actuator, where the penetrator was pushed at a constant rate of displacement into the specimen. The static tests reveal important mechanisms that govern the penetration process and therefore contribute to a better understanding of RC barriers resistance to non-deforming projectiles impact.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
• /
• pp.349-354
• /
• 1996

SACOM(Simulation Analyser with Cognitive Operator Model) is being developed at Korea Atomic Energy Research Institute to simulate human operator's cognitive characteristics during the emergency situations of nuclear power plans. An operator model with error mechanisms has been developed and combined into SACOM to simulate human operator's cognitive information process based on the Rasmussen's decision ladder model. The operational logic for five different cognitive activities (Agents), operator's attentional control (Controller), short-term memory (Blackboard), and long-term memory (Knowledge Base) have been developed and implemented on blackboard architecture. A trial simulation with a scenario for emergency operation has been performed to verify the operational logic. It was found that the operator model with error mechanisms is suitable for the simulation of operator's cognitive behavior in emergency situation.

• Nuclear Engineering and Technology
• /
• 제40권1호
• /
• pp.1-8
• /
• 2008

One of the major current challenges to nuclear energy lies in its competitiveness. To stay competitive the industry needs to reduce maintenance and fuel cycle costs, while enhancing safety features. Extended burnup is one of the methods applied to meet these objectives However, there are a number of potential fuel failure causes related to increased burnup, as follows: l) Corrosion of zirconium alloy cladding and the water chemistry parameters that enhance corrosion; 2) Dimensional changes of zirconium alloy components, 3) Stresses that challenge zirconium alloy ductility and the effect of hydrogen (H) pickup and redistribution as it affects ductility, 4) Fuel rod internal pressure, 5) Pellet-cladding interactions (PCI) and 6) pellet-cladding mechanical interactions (PCMI). This paper discusses current and potential failure mechanisms of these failure mechanisms.

• Clinical and Experimental Reproductive Medicine
• /
• 제46권3호
• /
• pp.99-106
• /
• 2019

Bisphenol A (BPA) is an endocrine-disrupting chemical that is capable of interfering with the normal function of the endocrine system in the body. Exposure to this chemical from BPA-containing materials and the environment is associated with deleterious health effects, including male reproductive abnormalities. A search of the literature demonstrated that BPA, as a toxicant, directly affects the cellular oxidative stress response machinery. Because of its hormone-like properties, it can also bind with specific receptors in target cells. Therefore, the tissue-specific effects of BPA mostly depend on its endocrine-disrupting capabilities and the expression of those particular receptors in target cells. Although studies have shown the possible mechanisms of BPA action in various cell types, a clear consensus has yet to be established. In this review, we summarize the mechanisms of BPA action in spermatozoa by compiling existing information in the literature.

• Computers and Concrete
• /
• 제23권2호
• /
• pp.107-119
• /
• 2019

In-service reinforced concrete structures are simultaneously subjected to a combination of multi-deterioration environmental actions and mechanical loads. The combination of two or more deteriorative actions in environments can potentially accelerate the degradation and aging of concrete materials and structures. This paper reviews the coupling and synergistic mechanisms among various deteriorative driving forces (e.g. chloride salts- and carbonation-induced reinforcement corrosion, cyclic freeze-thaw action, alkali-silica reaction, and sulfate attack). In addition, the effects of mechanical loads on detrimental environmental factors are discussed, focusing on the transport properties and damage evolution in concrete. Recommendations for advancing current testing methods and predictive modeling on assessing the long-term durability of concrete with consideration of the coupling effects are provided.

• Animal Bioscience
• /
• 제34권8호
• /
• pp.1271-1282
• /
• 2021

Genome-wide studies provide considerable insights into the genetic background of animals; however, the inheritance of several heritable factors cannot be elucidated. Epigenetics explains these heritabilities, including those of genes influenced by environmental factors. Knowledge of the mechanisms underlying epigenetics enables understanding the processes of gene regulation through interactions with the environment. Recently developed next-generation sequencing (NGS) technologies help understand the interactional changes in epigenetic mechanisms. There are large sets of NGS data available; however, the integrative data analysis approaches still have limitations with regard to reliably interpreting the epigenetic changes. This review focuses on the epigenetic mechanisms and profiling methods and multi-omics integration methods that can provide comprehensive biological insights in animal genetic studies.