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Graphical abstract, Introduction To enhance photothermal treatment (PTT) efficiency, a delivery method that uses cell vector for nanoparticles (NPs) delivery has drawn attention and studied widely in recent years. Objectives In this study, we demonstrated the feasibility of M1 activated macrophage as a live vector for delivering NPs and investigated the effect of NPs loaded M1 stimulated by Lipopolysaccharide on PTT efficiency in vivo. Methods M1 was used as a live vector for delivering NPs and further to investigate the effect of NPs loaded M1 on PTT efficiency. Non-activated macrophage (MФ) was stimulated by lipopolysaccharide (LPS) into M1 and assessed for tumor cell phagocytic capacity towards NPs Results We found M1 exhibited a 20-fold higher uptake capacity of NPs per cell volume and 2.9-fold more active infiltration into the tumor site, compared with non-activated macrophage MФ. We injected M1 cells peritumorally and observed that these cells penetrated into the tumor mass within 12 h. Then, we conducted PTT using irradiation of a near-infrared laser for 1 min at 1 W/cm2. As a result, we confirmed that using M1 as an active live vector led to a more rapid reduction in tumor size within 1 day indicating that the efficacy of PTT with NPs-loaded M1 is higher than that with NPs-loaded MФ. Conclusion Our study demonstrated the potential role of M1 as a live vector for enhancing the feasibility of PTT in cancer treatment.

Resumen Reportamos el caso de una paciente con cancer de mama, en la que la PET/TC osea doble fase con 18F-fluoruro de sodio (18F-NaF) resulto de utilidad para detectar metastasis oseas ocultas y valorar la respuesta al tratamiento. La paciente fue estudiada con PET/TC osea en doble fase de una lesion de nuevo desarrollo detectada en la gammagrafia posterior a la intervencion. En las imagenes PET/TC de perfusion y oseas, se encontraron captaciones en las fases de perfusion y osea, puntualmente incrementadas en el sacro y la vertebra L5, sugerentes de metastasis oseas del cancer de mama, por lo que se aplico a la paciente terapia paliativa. En las imagenes de PET/TC osea en doble fase, realizadas a los 3 y 6 meses, las imagenes de perfusion reflejaron mas claramente la mejora de la captacion de la lesion que las imagenes de la fase osea en los analisis visual y semicuantitativo. Por tanto, se utilizaron las imagenes de la fase de perfusion para esclarecer la respuesta a la terapia con mayor prontitud que las imagenes de la fase osea. Se trata del primer caso que refleja la utilidad clinica de la PET/TC osea con 18F-NaF, con la tecnica de imagen de perfusion, para evaluar las metastasis oseas y la respuesta terapeutica de las lesiones oseas metastasicas.

Underwater cutting of 50 and 60 mm thick stainless steel plates with a 6-kW fiber laser was performed as a fundamental study for application to dismantling nuclear facilities. For this purpose, an underwater cutting head was developed by upgrading our previously developed in-air cutting head. A waterproof function was added while the optical design of the in-air cutting head was maintained. In the developed head, a single supersonic minimum length nozzle was applied without any complicated nozzle features because it was enough to make a local-dry-zone. With this head, cutting tests were performed for pierced and non-pierced specimens. The pierced specimen showed a slightly better cutting performance than the non-pierced specimen. However, the cuttings were adequate for both types of specimens with thicknesses of 50 and 60 mm. In the cutting results for the non-pierced specimens, the maximum cutting speeds were 80 mm/min for the 50 mm thickness and 40 mm/min for the 60 mm thickness. To the best of our knowledge, the results from this study show the best cutting performance in terms of speed and thickness for the same laser power among the reported results of underwater laser cutting. The kerf width was also measured for each cutting. As in ordinary laser cutting, the kerf widths were narrow. For the cutting at each maximum speed, the kerf widths for the 50 mm thickness were 1.6 mm for the front surface and 0.7 mm for the rear surface, and the kerf widths for the 60 mm thickness were 1.5 mm for the front surface and 1.2 mm for the rear surface. It is expected that the results of this study will contribute to the continued development of underwater cutting research for dismantling nuclear facilities.

The cutting performance of thick steel plates and large size pipes with a 10 kW fiber laser was studied for the dismantling of nuclear facilities. First, thick steel plates of up to 100 mm were tried to be cut at a high speed. For the thickness of 100 mm, both stainless steel and carbon steel plates were cut at maximum cutting speeds of ∼30 mm/min. And narrow kerf widths of less than 5 mm were obtained for all cutting tests. Second, a 150-mm thick stainless steel plate near the cutting thickness limit was attempted to be cut. The specimen was able to be cut even with a low cutting speed of 3 mm/min. To the best of our knowledge, this thickness is the largest among the published reports with a laser power of 10 kW. And this corresponds to a cutting capability in which most thick structures in a nuclear reactor can be cut. In addition, large size stainless steel pipes were also attempted to be cut. For a 165 mm diameter pipe, it was possible to be cut at high speed by one scan at a speed of 50 mm/min and round trip scan at a speed of 100 mm/min. This result implies that high-speed cutting was also possible for most pipe-type components inside the nuclear reactor. As a result, our 10-kW laser cutting system showed very efficient cutting performance in terms of the cutting speed and thickness. Moreover, the cuttings showed narrow kerf widths of less than 5 mm even for very thick steel of up to 150 mm in thickness. In the future, it is expected that the results of this work will contribute to cutting thick metal structures as basic research data in the dismantling of nuclear facilities using a laser. In addition, it is also expected that this work will contribute to other industrial fields requiring a thick steel cutting technique.

A study was conducted to improve the cutting performance of a 60-mm thick stainless steel plate using a 6-kW fiber laser. Two techniques for improving the initial cutting performance were evaluated by preheating the work piece with a waiting time and step-like cutting speed increase. Both techniques showed improved cutting results compared to constant speed cutting. Among them, the method with a step-like cutting speed increase showed the better result in terms of cutting performance. As a result, a 60-mm thick stainless steel plate was cut at a maximum cutting speed of 72 mm/min with a preheating cutting speed of 24 mm/min. In order to confirm the effect of preheating, an additional experiment was performed to measure the temperature variation during the cutting process. Through this experiment, preheating temperature conditions were found to allow the specimen to be cut. It is expected that the results of this work will contribute to improving the cutting performance of thick metal structures in various industrial fields, as well as the dismantling of nuclear facilities using lasers in the future.

A cutting study with a high-power ytterbium-doped fiber laser was conducted for the dismantling of nuclear facilities. Stainless steel and carbon steel plates of various thicknesses were cut at a laser power of 6-kW. Despite the use of a low output of 6-kW, the cutting was successful for both stainless steel and carbon steel plates of up to 100 mm in thickness. In addition, the maximum cutting speeds against the thicknesses were obtained to evaluate the cutting performance. As representative results, the maximum cutting speeds for a 60-mm thickness were 72 mm/min for the stainless steel plates and 35 mm/min for the carbon steel plates, and those for a 100-mm thickness were 7 mm/min for stainless steel and 5 mm/min for carbon steel plates. These results show an efficient cutting capability of about 16.7 mm by kW, whereas other groups have shown cutting capabilities of ∼10 mm by kW. Moreover, the maximum cutting speeds were faster for the same thicknesses than those from other groups. In addition, the kerf widths of 60-mm and 100-mm thick steels were also obtained as another important parameter determining the amount of secondary waste. The front kerf widths were ∼1.0 mm and the rear kerf widths were larger than the front kerf widths but as small as a few millimeters.

In underwater laser cutting of steel plates thicker than 40 mm, the initial cutting speed was previously limited to 5–10 mm/min, because the generated melt could not be smoothly blown near the start point. Oblique cutting was considered a way to overcome this problem and speed up the initial cut. For this reason, underwater laser cutting tests were conducted to verify the improvement in initial cutting performance of thick steel plates through oblique cutting. First, constant speed cutting tests at oblique angle of 5° were performed on stainless steel plates. Compared to straight cutting, this method allowed initial cutting speed to be significantly increased. The maximum initial cutting speeds were 50, 25, and 15 mm/min for thicknesses of 48, 57, and 67 mm, respectively. When the oblique angle further increased to 15°, the initial cutting speed reached the maximum cutting speed achievable for each thickness. Therefore, there was no longer a need for 2-step cutting with low initial cutting speed. The maximum cutting speeds at the oblique angle of 15° were 100, 50, and 15 mm/min for thicknesses of 48, 57, and 68 mm, respectively. Additional cutting tests were performed for carbon steel plates. Due to the material properties of carbon steel, its cutting speed must be lower than that of stainless steel; however, all specimens were successfully cut at the oblique angle of 15°. The maximum cutting speeds of carbon steel plates were 40, 15, and 7 mm/min for thicknesses of 48, 59, and 69 mm, respectively.

One of the major concerns in target identification has been the need for new methods to detect target molecules in the native cellular environment. In conventional target identification, affinity-based pull down has been conducted using cell lysates. However, interactions in cell lysate do not reflect real endogenous interactions in living cells, and can produce false-positive or false-negative results. This study aimed to develop a new method of target protein identification in living cells. Targeting probes were conjugated onto magnetic nanoparticles (MNPs). After nanoparticle cellular uptake, identification and recruitment of target proteins were conducted in living cells, and the target protein was finally recovered under the magnetic field. As a proof-of-concept study, we developed a functionalized MNP (PTS1-MNP) to mimic a peroxisomal protein containing a synthetic peroxisomal targeting signal 1 (PTS1). The PTS1-MNPs were imported into human hepatoma HepG2 cells to recruit PTS1-receptor protein Pex5p. Successful peroxisomal translocation of PTS-MNPs was achieved via transient interaction with Pex5p. Pull-down of Pex5p in lysed or living HepG2 cells confirmed the selective recruiting functionality of synthetic PTS1. The specific detection of Pex5p before complete PTS1-MNPs translocation in living HepG2 cells further demonstrated the transient interaction between Pex5p and PTS1-MNPs. This is the first report showing the peroxisomal translocation of nanostructured materials in living cells. This approach can be applied as a new concept to study transient interactions and target identification or recruiting in living cells.

A lipase-sensitive singlet oxygen-producible and erythromycin-loaded liposome (LSSPL) was developed for combination antibacterial therapy for skin disorder. The LSSPL was synthesized by coating pullulan-pheophorbide a (PU-Pheo A) conjugates onto erythromycin-loaded liposomes composed of 1,2-dipalmitoyl-sn-phosphatidylcholine (DPPC) and cholesterol. Lipase activity was chosen as the environmental-stimulus for the controlled release of erythromycin and Pheo A from LSSPL because skin inflammation-inducing Propionibacterium acnes (P. acnes) secrete extracellular lipases. The presence of P. acnes lipases disrupted LSSPLs by selective cleavage of their ester linkages, liberating erythromycin and Pheo A. Along with the antibacterial effect of erythromycin, additional laser irradiation onto Pheo A further achieved the inhibition of P. acnes growth and treatment of P. acnes-infected inflammation in nude mice back skin. Therefore, antimicrobial therapy, using a stimulus-responsiveness moiety, presents a feasible way to treat bacteria-induced skin disorders.

Multipotent cells have similar basic features of all stem cells but limitation in ability of self-renewal and differentiation compared with pluripotent cells. Here, we have developed an ultra effective, gene- and chemical-free method of generating extra multipotent (xpotent) cells which have differentiation potential more than limited cell types, by the mechanism of ultrasound-directed permeation of environmental transition-guided cellular reprogramming (Entr). Ultrasound stimulus generated a massive number of Entr-mediated xpotent (x/Entr) spheroids from human dermal fibroblasts (HDFs) 6 days after treatment. The emergence of x/Entr was first initiated by the introduction of human embryonic stem cell (ESC) environments into the HDFs to start fast cellular reprogramming including activation of stress-related kinase signaling pathways, subsequent chromatin remodeling, and expression of pluripotent-related genes via transient membrane damage caused by ultrasound-induced cavitation. And then, pluripotent markers were transported into their adjacent HDFs via direct cell-to-cell connections in order to generate xpotent clusters. The features of x/Entr cells were intermediate between pluripotency and multipotency in terms of pluripotency with three germ layer markers, multi-lineage differentiation potential, and no teratoma formation. This physical stimulus-mediated reprogramming strategy was cost-effective, simple, quick, produced significant yields, and was safe, and can therefore provide a new paradigm for clinical application.

This study proposes a methodology to simulate the cutting process in a digital manufacturing platform for the flexible planning of nuclear facility decommissioning. During the planning phase of decommissioning, visualization and verification using process simulation can be powerful tools for the flexible planning of the dismantling process of highly radioactive, large and complex nuclear facilities. However, existing research and commercial solutions are not sufficient for such a situation because complete segmented digital models for the dismantling objects such as the reactor vessel, internal assembly, and closure head must be prepared before the process simulation. The preparation work has significantly impeded the broad application of process simulation due to the complexity and workload. The methodology of process simulation proposed in this paper can flexibly handle various dismantling processes including repetitive object cuttings over heavy and complex structures using a digital manufacturing platform. The proposed methodology, which is applied to dismantling scenarios of a Korean nuclear power plant in this paper, is expected to reduce the complexity and workload of nuclear dismantling simulations.

Video monitoring environment of underwater cutting objects is rapidly deteriorated due to the increasing water turbidity in proportion to cutting operation. Precise monitoring of the cutting area is one of keys to improve work efficiency. In this paper, we studied a visibility improvement technique based on an artificial neural network for monitoring objects in a turbid underwater cutting site. In order to improve visibility in turbid water, a deep learning neural network that learned two types of visibility enhancement process was adopted. The first type is to train to restore an ideal underwater image with the best visibility from a turbid underwater image, and the second type is to train to restore an image with improved visibility using the conventional visibility improvement technique. We adopted two types of training real images based on the GAN (generative adversarial networks) model for the corresponding turbid input images. The first training image is the histogram-equalized image of a clear underwater image. If the first training image does not exist, an image with improved visibility by using histogram equalization for the turbid input image itself was used as the second training image. Experiments demonstrated that the trained neural network provided significantly improved clarity in turbid images compared to that of the conventional improving technique.

Laser cutting was performed using a 6-kW fiber laser with two different nozzle configurations to extend the permissible cutting thickness of steel blocks in a water environment. The first nozzle configuration involved a single minimum length nozzle (MLN) operating at an upstream gas gauge pressure of 15 bar; the second configuration consisted of a truncated aerospike nozzle coupled with an MLN. These configurations were designed to form a core air-filled cavity with the submerged jet to have denser and more lengthened characteristics for extending the possible transmission distance of the high-power laser beam, which is vulnerable to water absorption. Before underwater cutting, we performed a Schlieren visualization measurement of the gas jet’s flow behavior as it was discharged from the single and dual nozzles in the ambient air, after which, the stainless steel blocks were laser-cut underwater using both nozzle configurations. The thickness of the selected steel blocks varied from 60 to 80 mm according to the capabilities of the nozzles used to form the air cavity.

This paper is intended to suggest a system for evaluation on the hazards from human errors during decommissioning of nuclear facilities. The system was developed under virtual networked environment. The innovative features are real-time changing direction of workers in a scenario and real-time measuring personal exposure dose and collective exposure dose. The system will be expected to be utilized as a training tool for improving familiarization of a workplace and for preventing workers from accidents.

Current methods for a process simulation cannot simulate the cutting-process flexibly. As is, to simulate a cutting-process, the user needs to prepare the cut product models of the cutting operation based on a cutting path and thickness with respect to a dismantling scenario in advance. In addition, the user need to build these preparations again as the scenario changes, which takes a lot of time. To solve this problem, we proposed a flexible cutting-process simulation methodology containing an automatic cut-product generation in the cutting-process modeling procedure. The cut products are created through CAD operations with the selected device models and the cutting path, which is input by the user. In addition, we implemented the methodology on a commercial system used to test the methodology.

A decommissioning plan should involve a comprehensive review of the feasibility of the safety measures, economics and so on. There is a variety of information required for the review of each decommissioning phase, ranging from the conformity of the dismantling process to radioactive waste management. The space dose rate of a nuclear facility is one of the major data points that must be obtained during the early planning stage for the decommissioning of a nuclear facility. We propose the framework for the visualization of the analyzed space dose rate on the dismantling simulation system with the solid modeling method, which is generally used for a CAD (computer-aided design)-based digital manufacturing platform. The visualization module applying this framework is implemented using the suitable software framework that can directly interface with the dismantling simulation system. The framework of the visualization module is composed of a pre-processing stage for creating an optimal data-structure of the analyzed space does rates and a configuration stage for a visualization of the 3-dimensional models of dose on the dismantling simulation system. As a result, the module in the dismantling simulation system can visualize both the 3-dimensional space dose rate and radioactive equipment model in the same virtual space and provides useful information to users in real time for planning the dismantling process.

This paper is intended to suggest an approach to an estimation of the work time to optimize the trajectories of workers during decommissioning of nuclear facilities. The working times during decommissioning for nuclear facilities have a great effect on safety and costs. The key feature of this work is to analyze and to evaluate the working times in virtual decommissioning environments. The measured data are statistically analyzed into the mean and variance work time and radiation exposure dose. It is expected that the safety of decommissioning will be improved and decommissioning costs can be reduced. It can be concluded that this work will make it possible to efficiently establish the ALARA plan for decommissioning of nuclear facilities.

This study is intended to suggest an ergonomic evaluation on the working postural comfort. This study issued for the first time a methodology in view of combination between visual field and comfort. Especially, the ergonomic evaluation using the virtual decommissioning environments is user-friendly because setup of physical mock-up environments is difficult. This study verified the front and standing postures are best working postures during movement under radiation environments of nuclear facilities. It is expected that this methodology will make it possible to establish the ergonomic plan for decommissioning of nuclear facilities and safety of decommissioning will be improved and also decommissioning costs also can be reduced.

For dismantling nuclear power plants, an underwater cutting study was conducted using a high power fiber laser. With a laser power of 9 kW, cutting tests were performed on stainless steel with a thickness of 50–100 mm. For this study, a waterproof cutting head consisting of a focusing element with a long focal length of 600 mm and a supersonic nozzle was used for high cutting efficiency. For thicknesses of 70 mm or less, it was possible to cut only with a single supersonic nozzle, while for a thickness of 80 mm or more, an initially pierced specimen or a double nozzle was required for successful cutting. Through these techniques, we were able to perform the cutting underwater up to a thickness of 100 mm. Furthermore, the kerf widths were as small as 1–2 mm, the amount of secondary waste will likely be small, which will reduce waste disposal costs.

An automated cutting procedure is required to dismantle high radioactive nuclear facilities. Also, the cutting scenario for the automated cutting procedure is built based on the digital mockup of the target facility before the physical cutting procedure begins. However, the digital mockup of the nuclear facility and the real site environmental data can be different in terms of the shape, location, and orientation of the nuclear facility’s components. Hence, without an as-built status verification, the worker needs to check the as-built status manually in the site. As a result, the automated cutting procedure is more costly than utilizing workers. Moreover, the procedures cannot be done successfully. We have also experienced the problem when we performed physical cutting tests based on the cutting scenario that was built using the digital mockup of the test-bed environment. In order to perform accurate physical cuttings in the site, the digital mockup needed to be updated based on the real site information before the physical cutting procedure was conducted. To do so, we obtained real site information using 3D scanning and applied spatial information processing technologies to update the digital mockup of a nuclear facility. Since creating a new model was time consuming, and because this process would have to be done manually, we did not create a whole as-built model based on the 3D scanning data. Instead, we updated the existing model, which is comprised of a complete and clean solid geometry. In this study, we proposed an overall digital mockup update framework based on the 3D scanned spatial information and implemented it based on the nuclear facility’s dismantling simulation software system.

Recently, microRNA (miRNA or miR) has emerged as a new cancer biomarker because of its high expression level in various cancer types and its role in the control of tumor suppressor genes. In cancer studies, molecular imaging and treatment based on target cancer markers have been combined to facilitate simultaneous cancer diagnosis and therapy. In this study, for combined therapy with diagnosis of cancer, we developed a doxorubicin-conjugated miR-221 molecular beacon (miR-221 DOXO MB) in a single platform composed of three different nucleotides: miR-221 binding sequence, black hole quencher 1 (BHQ1), and doxorubicin binding site. Imaging of endogenous miR-221 was achieved by specific hybridization between miR-221 and the miR-221 binding site in miR-221 DOXO MB. The presence of miR-221 triggered detachment of the quencher oligo and subsequent activation of a fluorescent signal of miR-221 DOXO MB. Simultaneous cancer therapy in C6 astrocytoma cells and nude mice was achieved by inhibition of miRNA-221 function that downregulates tumor suppressor genes. The detection of miR-221 expression and inhibition of miR-221 function by miR-221 DOXO MB provide the feasibility as a cancer theragnostic probe. Furthermore, a cytotoxic effect was induced by unloading of doxorubicin intercalated into miR-221 DOXO MB inside cells. Loss of miR-221 function and cytotoxicity induced by the miR-221 DOXO MB provides combined therapeutic efficacy against cancers. This method could be used as a new theragnostic probe with enhanced therapy to detect and inhibit many cancer-related miRNAs.

This paper is intended to suggest an approach to the methodology of evaluation on abnormal accidents from human errors during decommissioning of nuclear facilities. A structure of model was established and a mathematical method was also designed to evaluate both normal and abnormal environments. The proposed methodology was verified by applying a practical test case of decommissioning scenarios using the assessment system in virtual decommissioning environment.

This paper is to establish the hazard reduction methodology for decommissioning of nuclear facilities. There are radiological and non-radiological hazards during decommissioning of nuclear facilities. Based on a review of industrial methods and requirements of decommissioning safety, a method of hazard reduction has been designed and a mathematical method of cost estimation has been developed using a parametric method.

This paper is to suggest the assessment model on human errors for decommissioning of nuclear facilities. On the basis of evaluation items, the structure of the model was systematically established and the method for the model was quantitatively designed. The categories of evaluation items consist of ‘psychological’, ‘physical’, ‘man-machine’, and ‘environmental’. The method is composed of scaling and weighting factors. Feasibility study of the method was accomplished by applying a scenario.

Current methods for delivering foreign genetic materials into mammalian cells are highly successful. However, these methods cannot be applied in oocyte or embryo systems due to their toxicity and low efficiency. Moreover, no satisfactory methods exist for delivering foreign genetic material without inducing physical damage to membranes. Here we developed an organic compound (VisuFect)-mediated small interfering RNA (siRNA) delivery method and evaluated this method in P19 cells and mouse zygotes. Oct4-siRNA conjugated VisuFect (Oct4-siRNA-VF) permeated the zona pellucida effectively and localized inside mouse zygotes without inducing membrane damage. Successful VisuFect-mediated delivery was further demonstrated by strong transcriptional repression of Oct4 expression by the delivered Oct4-siRNA, in addition to repressed embryonic development of mouse zygotes.

A double textured selective emitter (DTSE) solar cell was fabricated using Si wafer. The 40 × 40 mm 2 silicon substrates were textured to form a pyramid-shaped surface, and nanowires were fabricated by a metal-assisted chemical etching process using Ag nanoparticles. All surface modifications of the micro and nanostructures were done by a wet-based process. The heavily doped and shallow emitters for selective emitter solar cells were prepared through the POCl 3 diffusion and a chemical etch-back process, respectively. The front and rear electrodes were prepared with a conventional screen printing method. The optical properties were enhanced through the double textured (DT) structure, and additional enhancement of the electrical properties was realized through the selective emitter concept. The DTSE solar cell achieved a higher conversion efficiency of 17.9% with improved absorption and short circuit current density compared to a DT solar cell.

This paper discusses the rolling blackouts implemented by the Korea Electric Power Corporation (KEPCO) on September 15, 2011, and a low-frequency oscillation that occurred at that time. On the day of the rolling blackout, spectral analysis and mode analysis were performed using the data obtained from a synchrophasor installed in the KEPCO system. Low-frequency oscillation modes near 0.68 Hz and 0.5 Hz occurring respectively before and during the process of forced load shedding were estimated. These wide-area oscillation modes may cause total blackouts, and may be good indicators of reliable system operation in the event of similar wide-area rolling blackouts in the future.

A seamless remote system for dismantling heavy and highly radioactive components during the decommissioning of a nuclear power plant is proposed. The originality of the dismantling system is in its ability to handle all the processes involved in the dismantling of major components of a nuclear power plant without external intervention. Previous types of dismantling equipment were designed for specific components or a particular process, which required time consuming and risky equipment replacement tasks between different processes. The proposed dismantling system was designed and verified by simulation of all the processes for dismantling the major components of a Korean nuclear power plant. Several challenges such as working in confined spaces and with complex movement lines as well as interference between components were overcome. The proposed system is capable of handling all the dismantling processes without equipment replacement tasks or the need to drain the reactor pool. The system is expected to considerably reduce the time and cost of the entire decommissioning process while also improving safety.

This paper is meant to develop the training system to prevent accidents during decommissioning of nuclear facilities. Requirements of the system were suggested. Data management modules of the system were designed. The system was developed on virtual reality environment. The performance test of the system was proved to be appropriate to decommissioning of nuclear facilities.

This paper is to evaluate on alternative cutting technologies for decommissioning of the components in a nuclear power plant. Physical characteristics of the components were analyzed. Alternative cutting technologies of the components were evaluated. The optimal cutting technologies of the components in a NPP were suggested.

This paper is to develop the digital mock-up system to simulate the dismantling scenarios for decommissioning of a NPP. Features of the digital mock-up system are kinematic simulation and human simulation of decommissioning scenarios of a NPP. The digital mock-up consists of major components, internals, support facilities, and equipments. The digital mock-up system could evaluate and optimize the decommissioning scenarios of a NPP.

The laser cutting of 60-mm-thick stainless steel using a 6-kW fiber laser was performed to investigate the effect of the geometric nozzle configuration on the operating tolerance of the stand-off distance. The stand-off distance is the distance between the nozzle tip and the top surface of the steel plate. Two types of nozzles—a subsonic nozzle with a convergent geometry and a supersonic nozzle with a convergent-divergent geometry—were used to comparatively evaluate the flow behavior through interferometric analysis. A laser cutting experiment was conducted in accordance with the interferometric analysis, focusing on the stand-off distance variation. The stand-off distance was varied from 1 to 60 mm in consideration of the melt-removal capability of the applied cutting nozzles. The throat diameters of the nozzles were 2 and 3 mm. According to the results, the supersonic nozzle has a better operating tolerance of the stand-off distance for the laser cutting of 60-mm-thick stainless steel.

Decommissioning activities include radiological hazards and non-radiological hazards. Radiological hazards are mainly due to radiation exposure whereas non-radiological hazards are mainly due to industrial hazards such as fire, explosions, toxic materials, and electrical and physical hazards. Based on characteristics of decommissioning activities, risk calculation method of decommissioning hazards and countermeasures of radiological hazards and non-radiological hazards were suggested.

Industrial applicable fine-line double printing and nickel plating method was applied to single crystalline silicon (c-Si) solar cells. As the finger widths decreased, the efficiency and short circuit current density (JSC) linearly increased. Although the increase of the JSC was caused by the reduction of shadowing loss due to the decrease of finger width, the fill factor (FF) was slowly decreased due to increase of contact resistance. The FF of the cells using the fine line was enhanced by using a double printing and nickel plating. c-Si solar cells with the dimensions of 12.5 cm × 12.5 cm, double printed finger width of 50 μm due to spreadability of paste, a finger spacing of 2.4 μm, and aluminum back surface field were fabricated, achieving an increase of JSC and efficiencies of up to about 0.62 mA/cm2 and 0.38% compared to a reference cell at 79.8% of the FF, respectively.

Indium Tin Oxide (ITO) with a refractive index of 1.9 is an appropriate material for the anti reflection coating (ARC) layer of solar cells. In this report, we present a cost effective and low temperature approach to fabricate a crystalline silicon (c-Si) solar cell with a low resistance and highly transparent ITO ARC layer. Deposition conditions of ITO film by RF magnetron sputtering were varied to investigate the best condition for crystalline silicon solar cell application. Optical and electrical properties of the ITO film deposited under the best condition resulted in transmittance of 93.23%, reflectance of 3.23% and resistivity of 3 × 10− 4 Ω-cm. The result is comparable to the SiNX layer widely used as ARC material in the crystalline silicon solar cell fabrication process. ITO film formed a perfect ohmic contact with the emitter layer with high surface concentration. Finally, a solar cell was fabricated with best deposition condition of ITO on the emitter layer with a sheet resistance of 100 Ω/□. We obtained open circuit voltage of 600 mV, short circuit current of 36.15 mA/cm2 and conversion efficiency of 16.8% under this condition.

One of the main objectives of the current single c-Si photovoltaic research is to enhance solar cell efficiency with the low cost approach. A simple way to improve the solar cell efficiency is to enhance the absorption of light as much as possible. In this study, we reduced the finger width pattern from 80 μm to 30 μm and then double printed to minimize shadow loss without any increase in series resistance. The single screen printing of 80 μm finger width resulted in efficiency of 17.66%, whereas 30 μm finger width resulted in efficiency of 15.83%, which is due to a decrease in FF. An 18.06% efficient solar cell with Jsc of 37.31 mA/cm 2 , Voc of 627.3 mV and FF of 77.2% is obtained using the double screen printing pattern of 30 μm wide fingers. The increase in finger thickness resulted in increase in FF and hence efficiency. This novel method can be applied for mass production due to the simple double screen printing process.

To survive the cut-throat competition in the manufacturing industry, many companies have introduced digital manufacturing technology. Digital manufacturing technology not only shortens the product development cycle times but also improves the precision of engineering simulation. However, building the virtual objects needed for a digital manufacturing environment requires skilled human resources; it is also costly and time-consuming. A high precision environment with the similar resources is also needed for a high precision simulation. In this paper, we propose a method of constructing a mixed reality-based digital manufacturing environment. The method integrates real objects, such as real images, with the virtual objects of a virtual manufacturing system. This type of integration minimizes the cost of implementing virtual objects and enhances the user's sense of reality. We studied several methods and derived a general framework for the system. Finally, we developed our idea into a virtual factory layout planning system. To assign the pose and position of real objects in virtual space, we applied a circle-based tracking method which uses a safety sign instead of the planar-square-shaped marker generally used for registration. Furthermore, we developed the framework to encapsulate simulation data from legacy data and process data for visualization based on mixed reality.

This paper is to evaluate the cutting technologies for decommissioning of the large cylinder parts in the major components of nuclear power plants. Physical characteristics of the large cylinder parts were analyzed and alternative cutting technologies of the large cylinder parts were evaluated. An optimal cutting technology for decommissioning of the large cylinder parts in the major components of NPPs was suggested.

This paper is to suggest an evaluation method on the dismantling technologies for decommissioning of nuclear power plants. The parameters of evaluation are performance impacts, site-specific impacts, safety impacts, and cost impacts. The evaluation model was provided and applied for dismantling of a steam generator.

Stable colloidal dispersions of magnetite (Fe(3)O(4)) nanoparticles (MNPs) were obtained with the inclusion of an amphiphilic comblike polyethylene glycol derivative (CL-PEG) as an amphiphilic polymeric surfactant. Both the size and morphology of the resulting CL-PEG-modified MNPs could be controlled and were characterized by transmission electron microscopy (TEM). The interaction between MNPs and CL-PEG was confirmed by the presence of characteristic infrared absorption peaks, and the colloidal stability of the nanoparticle dispersion in water was evaluated by long-term observation of the dispersion using UV-visible spectroscopy. SQUID measurements confirmed the magnetization of CL-PEG-modified MNPs. The zeta potential of the CL-PEG-modified MNPs showed a dramatic conversion from positive to negative in response to the pH of the surrounding aqueous medium due to the presence of carboxyl groups at the surface. These carboxyl groups can be used to functionalize the MNPs with biomolecules for biotechnological applications. However, regardless of surface electrostatics, the flexible, hydrophilic side chains of CL-PEG-modified MNPs prevented the approach of adjacent nanoparticles, thereby resisting aggregation and resulting in a stable aqueous colloid. The cytotoxicity of MNPs and CL-PEG-modified MNPs was evaluated by a MTT assay.

This paper introduces strategies for enhancement of a surface plasmon resonance (SPR) signal by adopting colloidal gold nanoparticles (AuNPs) and a SiO(2) layer on a gold surface. AuNPs on SiO(2) on a gold surface were compared with an unmodified gold surface and a SiO(2) layer on a gold surface with no AuNPs attached. The modified surfaces showed significant changes in SPR signal when biomolecules were attached to the surface as compared with an unmodified gold surface. The detection limit of AuNPs immobilized on a SPR chip was 0.1 ng mL(-1) for the prostate-specific antigen (PSA), a cancer marker, as measured with a spectrophotometer. Considering that the conventional ELISA method can detect approximately 10 ng mL(-1) of PSA, the strategy described here is much more sensitive (approximately 100 fold). The enhanced shift of the absorption curve resulted from the coupling of the surface and particle plasmons by the SiO(2) layer and the AuNPs on the gold surface.

The purpose of this paper is to evaluate the removal alternative methods of heavy components in nuclear power plants. One of the important tasks in decommissioning a nuclear power plant is removal of heavy components. The removal alternative methods of heavy components as a whole body are composed of three methods. This paper presented the best alternative method of RPV removal.

An analytical model and analysis of the low frequency noise performance of ultrathin oxide MOSFETs are presented. The model includes the effects of gate tunneling leakage current, low frequency noise sources, and their cross correlation coefficient between the input and the output. The correlation coefficient is not negligible in the existence of direct tunneling current through the gate oxide, and has an impact on the overall noise performance at low frequencies. Based on the partition noise theory and BSIM4 gate leakage current model with the source–drain partition, the correlation coefficient is obtained from a physical and rigorous modeling of intrinsic noise sources. The calculated results are compared with correlation noise measurements and good agreement is observed. An analytical formulation of low frequency noise performance is newly derived using the frequency-dependent noise parameters P LF , R LF , and C LF . The noise performance parameters, such as minimum noise figure, optimum source resistance and reactance, are graphically presented to accurately predict the influence of the gate leakage current on the low frequency noise performance. From quantitative results simulated with typical device parameters, it is shown that the proposed model can be used for optimum design of ultrathin oxide MOS devices and circuits at low frequencies.

The electrical trap properties in ultrathin oxide MOSFETs are extracted using 1/ f γ low frequency noise components of gate leakage current. The technique is based on the low frequency noise measurements which are capable of probing trap states over the energy and space. The gate voltage is swept between 0.4 and 1.32 V to obtain the different power slopes γ of 1/ f γ noise spectrum. From the measured noise data, the trap parameters such as slow trap densities and capture cross-section are accurately determined as a function of trap energy and trap distance. The 1/ f γ noise measurement results confirm that the capture cross-sections depend strongly on the surface potential, and the slow trap densities estimated near the band edge and at the Si–SiO 2 interface are higher than those near the midgap and deeper distance. Moreover, the parallel conductance spectroscopy of slow traps is reproduced by 1/ f γ low frequency noise measurements, and is verified by the low frequency plateau in measured conductance loss G p ( f )/ w . For the purpose of investigating the dependency of trap parameters on the complex admittance of oxide traps, the Cole–Cole plots for different trap profiles, a uniform and exponentially decreasing trap distribution in space, are calculated using the theoretical model. The noise spectroscopy technique further reveal the dynamic evolution of trap states and gives a clear physical understanding of the pertinent low frequency noise sources.