[en] Highlights: • Bacterial extracelluar enzymes stabilized the silver nanoparticles (AgNPs). • AgNPs formation was characterized by analytical techniques such as UV–vis, TEM, and FTIR. • AgNPs showed obvious antimicrobial activity against both gram positive and gram negative microorganisms. • A mechanism of AgNPs’ antimicrobial activity was proposed. -- Abstract: The development of eco-friendly and reliable processes for the synthesis of nanoparticles has attracted considerable interest in nanotechnology. In this study, an extracellular enzyme system of a newly isolated microorganism, Exiguobacterium sp. KNU1, was used for the reduction of AgNO₃ solutions to silver nanoparticles (AgNPs). The extracellularly biosynthesized AgNPs were characterized by UV–vis spectroscopy, Fourier transform infra-red spectroscopy and transmission electron microscopy. The AgNPs were approximately 30 nm (range 5–50 nm) in size, well-dispersed and spherical. The AgNPs were evaluated for their antimicrobial effects on different gram negative and gram positive bacteria using the minimum inhibitory concentration method. Reasonable antimicrobial activity against Salmonella typhimurium, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus was observed. The morphological changes occurred in all the microorganisms tested. In particular, E. coli exhibited DNA fragmentation after being treated with the AgNPs. Finally, the mechanism for their bactericidal activity was proposed according to the results of scanning electron microscopy and single cell gel electrophoresis

[en] In this study, Prussian blue-graphene oxide (PB-GO) hydrogel beads were synthesized to remove cesium from aqueous solutions. The PB-GO composites were prepared as PB nanoparticles attached to the surface of multi-layered GO sheets. The PVA-alginate hydrogel beads with PB-GO on their cross-linked structure were prepared and packed in a fixed-bed column system. The effect of various parameters, such as initial cesium concentration, flow rate, bed height, and adsorbent size, on the removal of cesium in the fixed-bed column system was investigated. Furthermore, the Thomas, Adams–Bohart, and Yoon–Nelson models were used to analyze the breakthrough curves using non-linear regression methods. The PB-GO hydrogel beads have a strong potential as an efficient adsorbent for the treatment of wastewater polluted with cesium in continuous operation mode

[en] In this study, three-dimensional (3D) MXene (Ti₃C₂T_x) films with high adsorption capacity, good mechanical strength, and high selectivity for specific radionuclide from aquose solution were successfully fabricated by a polymeric precursor method using vacuum-assisted filtration. The highest removal efficiency on the films was 99.54%, 95.61%, and 82.79% for Sr2⁺, Co2⁺, and Cs⁺, respectively, using a film dosage of 0.06 g/ L in the initial radionuclide solution (each radionuclide concentration = 1 mg/L and pH = 7.0). The expanded interlayer spacing of Ti₃C₂T_x sheets in MXene films showed excellent radionuclide selectivity (Cs⁺ and/or Sr²⁺/Co²⁺) (Simon, 2017). Besides, the MXene films was not only able to be easily retrieved from an aqueous solution by filtration after decontamination processes, but also to selectively separate desired target radionuclides in the solutions. Therefore, the newly developed MXene (Ti₃C₂T_x) films has a great potential for radionuclide removal from aqueous solution

[en] Nuclear energy has been used as a major energy source for generating electricity because of economic efficiency and efficiency in Korea. Countries such as Japan and Korea that have a high dependency on imported energy sources such as oil and gas have continued to expand the proportion of electricity supply and demand through nuclear power generation. The Korea government also declared the energy shift from nuclear energy to renewable energy such as wind and sunshine energy. The purpose of this paper is to present the direction of future nuclear energy industry in Korea under the aspect of the national assembly’s legislation and political Party’s declaration. From the above, most of the political parties’ declaration and the national assembly’s proposed legislation show a tendency toward an energy policy shift from nuclear energy, that is currently accepting to the public. Stake holders of the nuclear energy field shall consider this trend and need to respond properly.

[en] Since the 2011 Fukushima nuclear accident and the 2016 Kyongju earthquake, domestic concern for nuclear power has grown rapidly and demands for nuclear safety have come to the fore. As a result, the current government has announced the eighth basic plan for power supply in 2017, which has a lot of radical changes. This has led to disagreements among related stakeholders, leading to legal disputes. In this study, we will review the basic outline of the Eighth Basic Plan for Electricity Supply and Demand, and analyze main legal issues of administrative revocation lawsuit against the Korea government for cancelling the Plan. In the future, the court will closely examine whether the plan has the disposition power to be the object of the administrative litigation and whether the plaintiffs are qualified as specific and direct victims of the plan. This lawsuit shall be a very meaningful legal case in the fields of legal academy and nuclear industry

[en] Since the Fukushima nuclear power plant accident in Japan 2011 and the Kyungjoo earthquake in Korea 2016, Korea government has insisted on diminishing of nuclear energy dependency and strengthened the safety regulation of nuclear power plants. In the aftermath of the above transition of the current administration, new amendment of the Korea nuclear liability law is proposed to congress, which deletes current maximum liability limit of nuclear facility operator (300 million SDR1 ; about / 500 billion Won) per nuclear accident. In this study, we analyze the international trend of nuclear liability system and explain what to consider before changing nuclear operatorsĜ liability from limited liability to infinite liability system. We have looked at international trends in nuclear energy liability limits. It is necessary to comprehend the legislative intention of the countries which still maintain the limited liability system in order to balance between keeping a sound nuclear industry for sustainable energy supply and protection of the victims from nuclear accident.

[en] Flows around two oscillating cylinders in side-by-side arrangement at Re=185 are simulated using an immersed boundary method. The cylinders oscillate vertically in opposite directions in uniform cross-flow. We describe flow patterns, drag and lift forces by varying distance between two cylinders (1.4≤g≤2.2, 1.0≤g≤1.8) and oscillating frequency ratio (∫_e/∫_o=0.8, ∫_e/∫_o=1.0 and ∫_e/∫_o=1.2). Wake patterns, drag and lift coefficients are affected by both of frequency ratio and gap between two cylinders. Near wakes of each case are classified with the definition of previous studies

[en] Pressure on the researcher has been increased by R and D competition and outcome-oriented evaluation system in the circumstance of increased R and D investment of government and high speed of technological development. Education for research ethics and conscience is more needed for the purpose of researcher's healthy and sound research attitude in this high pressured research environment. This textbook and educational module for research ethics are produced in order to satisfy the need. The text book, 'practical research ethics', is consisted of three chapters. Chapter one, Consciousness of the Research Ethics, deals with the background, definition, and importance of the ethics. Second chapter, Communion, discusses responsible research attitudes, and verification process under research ethical guideline. Chapter 3, Practice of Research Ethics, demonstrates practical guideline. Code and Rules of Ministry of Science and Technology related with the issues and foreign cases are compiled in appendix. Educational module for the textbook includes diverse materials, examples, and video. Educational technique for the module adopts participants' discussion, case analysis, and brain-storming. Applying the textbook and education module into each R and D Institute and academy is expected with suitable modification of each situation. The process will bring up internal discussion and consensus on the research ethics. Case analysis and composing network for practical adopting process will be the next step of this study

[en] IBM (Immersed Boundary Method) with feedback momentum forcing was applied to stationary and moving bodies. The capability of IBM to treat the obstacle surfaces, especially with moving effect has been tested for two dimensional problems. Stationary and oscillating cylinders were simulated by using IBM based on finite volume method with Cartesian coordinates. For oscillating cylinder, lateral and vertical motions are considered, respectively. Present results such as time histories of drag and lift coefficients for both stationary and oscillating cases are in good agreement with previous numerical and experimental results. Also, the instantaneous wake patterns of oscillating cylinder with different oscillating frequency ratios well represented those of previous researches. More feasibility study for IBM has been carried out to two oscillating cylinders. Drag and lift coefficients are presented for two cylinders oscillating sinusoidally with phase difference of 180 .deg

[en] Energy has recently come to be regarded as the major factor in production, replacing land. Mankind will confront a critical turning point in the energy supply in the 21. century. Since the industrial revolution, fossil-fuel based production has been revealing the limits of growth, such as the depletion of fossil fuels and the various conflicts caused by it. The nature of the problem is structural, not economic cycle. The Republic of Korea has the sixth largest installation of nuclear power plants in the world. Nuclear energy has been actively promoted for 40 years since the seventies, in the South Korea. It has enabled a stable mass production of electricity to be supplied at a competitive price, and for South Korea to become an industrialized country. Nuclear energy is expected to play the following roles in the future: -) as a core energy source for shifting to a post-petroleum society; -) as a key technology for shifting to a low-carbon energy society; -) as a technology for achieving an energy self-sufficient society; -) as the response to changes in future energy demand patterns; -) as a job creator technology for new growth engines; -) as a contributor to energy welfare. For playing these roles, South Korea makes considerable efforts in the development of infrastructure and technology in the nuclear energy field. Moreover, South Korea strives to contribute to a safe and transparent use of global nuclear energy through active international cooperation in order to share valuable experience of nuclear energy use and to play an important role in the world. (authors)