• Mass Spectrometry Letters
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• v.10 no.1
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• pp.27-31
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• 2019

In this article, the properties of ${CO_2}^+(CO_2)_n$ clusters in a Paul ion trap have been investigated using mass-selective instability mode which conducted by chosen precursor ions, mainly $Ar^+$ and ${CO_2}^+$ produced by a mixture of Ar and $CO_2$. Exposure of ${CO_2}^+$ ions to $CO_2$ molecules, lead to the formation of ${CO_2}^+(CO_2)_n$ clusters. Here, Ar gas react as a buffer gas and lead to form ${CO_2}^+(CO_2)_n$ cluster by collisional effect.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.252-254
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• 2007

Image fusion is fast catching attention as Wagner pointed out in his 2006 version of the recent progress and development presented at the annual meeting of Society of Nuclear Medicine. Prototypical fusion of bone scan and radiograph was already attempted at in 1961 when Fleming et al. published an article on strontium-85 bone scan. They simply superimposed dot scan on radiograph enabling simultaneous assessment of altered bone metabolism and local bone anatomy. Indeed the parallel reading of images of bone scan and radiography, CT, MRI or ultrasonography has been practiced in nuclear medicine long since. It is fortunate that recent development of computer science and technology along with the availability of refined CT and SPECT machines has permitted us to open a new avenue to digitally produce precise fusion image so that they can readily be read, exchanged and disseminated using internet. Ten years ago fusion was performed using Bresstrahlung SPECT/CT and it is now achievable by PET/CT and SPECT/CT software and SPECT/CT hardware. The merit of image fusion is its feasibility of reliable assessment of morphological and metabolic change. It is now applicable not only to stationary organs such as brain and skeleton but also to moving organs such as the heart, lung and stomach. Recently, we could create useful fusion image of cardiac SPECT and 64-channel CT angiograph. The former provided myocardial metabolic profile and the latter vascular narrowing in two patients with coronary artery stenosis and myocardial ischemia. Arterial stenosis was severe in Case 1 and mild in Case 2.

• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.709-714
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• 2009

An ion implanter, which can serve as a metal-ion supply, has been constructed and performance tested. Copper ions are generated and extracted from a Bernas ion source with a heating crucible that provides feed gases to sustain the plasma. Sable arc plasmas can be sustained in the ion source for a crucible temperature in excess of $350^{\circ}C$. Stable extraction of the ions is possible for arc Currents less than 0.3 A. Arc currents increase with the induced power of a block cathode and the transverse field in the ion source. $Cu^+$ ions in the extracted beam are separated using a dipole magnet. A $20{\mu}A$ $Cu^+$ ion current can be extracted with a 0.2 A arc current. The ion current can support a dose of $10^{16}ions/cm^2$ over an area of $15\;cm^2$ within a few hours.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1736-1746
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• 2021

The results of full-scale numerical experiments of a hybrid thorium-containing fuel cell facility operating in a close-to-critical state due to a controlled source of fusion neutrons are discussed in this work. The facility under study was a complex consisting of two blocks. The first block was based on the concept of a high-temperature gas-cooled thorium reactor core. The second block was an axially symmetrical extended plasma generator of additional neutrons that was placed in the near-axial zone of the facility blanket. The calculated models of the blanket and the plasma generator of D-T neutrons created within the work allowed for research of the neutronic parameters of the facility in stationary and pulse-periodic operation modes. This research will make it possible to construct a safe facility and investigate the properties of thorium fuel, which can be continuously used in the epithermal spectrum of the considered hybrid fusion-fission reactor.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.100-108
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• 2023

In this study, a neural network model inspired by a one-dimensional convolution U-net is developed to automatically accelerate edge localized mode (ELM) detection from big diagnostic data of fusion devices and increase the detection accuracy regardless of the hyperparameter setting. This model recognizes the input signal patterns and overcomes the problems of existing detection algorithms, such as the prominence algorithm and those of differential methods with high sensitivity for the threshold and signal intensity. To train the model, 10 sets of discharge radiation data from the KSTAR are used and sliced into 11091 inputs of length 12 ms, of which 20% are used for validation. According to the receiver operating characteristic curves, our model shows a positive prediction rate and a true prediction rate of approximately 90% each, which is comparable to the best detection performance afforded by other algorithms using their optimized hyperparameters. The accurate and automatic ELM-burst detection methodology used in our model can be beneficial for determining plasma properties, such as the ELM frequency from big data measured in multiple experiments using machines from the KSTAR device and ITER. Additionally, it is applicable to feature detection in the time-series data of other engineering fields.

• Journal of Embryo Transfer
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• v.14 no.2
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• pp.107-111
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• 1999

The present study was performed to evaluate the best electric fusion condition in nuclear transfer, Korean Native Cattle fibroblasts were used as nucleic donors. Oocytes from slaughterhouse were matured in vitro for 22 h and enucleated. Each individual cells were transferred into enucleated ocytes and reconstructed embryo were placed into the fusion chamber. In experiment 1, pulse were performed by altering pulse duration at 1. 75kv/cm, 1 time. When pulse duration is 30$mutextrm{s}$, fusion and development rates is higher than other conditions. In experiment 2, the effect of different pulse number were studied at the pulse duration 30$mutextrm{s}$ and the same pulse intensity. When pulse number was one, fusion rates were higher than other conditions. The fused embryos were moved to culture medium and assessed their development to blastocyst. These results showed that best fusion condition was 30$mutextrm{s}$ and one time. And the fibroblasts derived from Han Woo can be reprogrammed by nuclear transplantation and develop subsequently in vitro.

• Journal of the Korean Ceramic Society
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• v.54 no.1
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• pp.9-22
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• 2017

Many new functional materials have been studied for efficient production and storage of energy. Many new materials such as sodium-based and sulfide-based materials have been proposed for energy storage, but research on Li batteries is still dominant. Due to the influence of environmental concerns regarding nuclear energy, interest in and research on fusion power are steadily increasing. For the commercialization of nuclear fusion, a design standard based on a considerable level of physical analysis and modeling is proposed. Nevertheless, limitations of existing materials in nuclear fusion environments limit practical applications. Tritium propagation material for continuous fusion reaction is one of the core materials, and therefore research on this material is being carried out intermittently. The key material for Li-based energy storage and tritium generation is the functional material Li-M-O. In this review, a structural description of functional Li-M-O system materials and technical trends for its applications are introduced.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3342-3351
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• 2023

High-density polyethylene (HDPE) pipelines in nuclear power plants (NPPs) have to meet high requirements for seismic performance. HDPE pipes have been proved to have good seismic performance, but joints are the weak links in the pipelines, and pipeline failures usually initiate from the defects inside the joints. Limited data are available on the seismic performance of butt-fusion joints of HDPE pipelines in NPPs, especially in terms of defects changes inside the joints after earthquakes. In this paper, full-scale shaking table tests were performed on a test section of suspended HDPE pipelines in an NPP, which included straight pipes, elbows, and 10 butt-fusion joints. During the tests, the seismic load-induced strain of the joints was analyzed by strain gauges, and it was much smaller than the internal pressure and self-weight-induced strain. Before and after the shaking table tests, phased array ultrasonic testing (PA-UT) was conducted to detect defects inside the joints. The locations, numbers, and dimensions of the defects were analyzed. It was found that defects were more likely to occur in elbows joints. No new defect was observed after the shaking table tests, and the defects showed no significant growth, indicating the satisfactory seismic performance of the butt-fusion joints.

• Nuclear Engineering and Technology
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• v.42 no.3
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• pp.305-312
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• 2010

The protection sequence of an AC/DC converter for an ITER PF coil system is developed in this study. Possible faults in the coil system are simulated and the results reflected in the design of a sequence to protect the coil and converter. The inductances of the current sharing reactors and thyristor numbers in parallel with the bridge arms are optimized with the designed protection sequence.

• Nuclear Engineering and Technology
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• v.38 no.8
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• pp.793-802
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• 2006

The design concept of a bending magnet to be installed in the KSTAR NBI system is presented. It is the function of a bending magnet that removes unconverted ions from the main beam stream and produces an 8 MW, 120 keV deuterium neutral beam. In order to determine the proper size and shape of the bending magnet, a parametric study on the B-field pattern was carried out by changing the dimensions of the pole face model. In addition, the detailed trajectories of the dominant ion species produced in the beam line were calculated. The electrical and cooling parameters of the coil assembly were also estimated.