• Journal of Environmental Science International
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• v.15 no.11
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• pp.1027-1034
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• 2006

Antimicrobial powder was made by exchanging silver ion on calcined oyster shell. On the purpose of application to water clarifier, bail-type media mixed with antimicrobial powder and $0{\sim}30%$ white kaoline were made. The sterilization effect, pore size distribution and zeta potential was tested to indicate the condition for the media of water clarifier. From these tests, it was confirmed that this media have an excellent sterilization power on $G^-\;and\;G^+$ germs. As the concentration of the exchanged silver ion increased, the surface charge density of the anions on the surface of the media also increased. The surface pore size decreased with the concentration of silver ion and 20% more white kaoline ratio. Consequently, mixing ratio of white kaoline would appear to indicate the optimun condition as media have sterilization power.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.750-757
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• 2009

The ammonium ion exchange characteristics of natural zeolite were investigated to remove ${NH_4}^+-N$. The effect of water temperature, particle size and competitive cation on the exchange capacity was examined. Ammonium ion exchange capacity tended to decrease when the temperature increased from $25^{\circ}C$ to $40^{\circ}C$. Exchange capacity was increased according to the particle size of natural zeolite comes to be small. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir isotherm model or by the Freundlich isotherm model. The ammonium ion exchange capacity ($q_m$) of zeolite carrier can be calculated $11.744mg-{NH_4}^+/g$-carrier. The ion exchange capacity of manufactured zeolite carrier was showed a similar tendency as ion exchange capacity of powder-sized natural zeolite. Therefore, zeolite carrier can be used for increasing of nitrogen removal efficiency in the wastewater treatment plants.

• Journal of Environmental Health Sciences
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• v.31 no.5 s.86
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• pp.387-397
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• 2005

In oder to understand the deposition possibility of water-soluble inorganic ions in the atmospheric fine particulates for the human respiratory tract, the mass size distribution of ion species was measured using an Anderson sampler in the Iksan during fall, 2004. Samples were analyzed for major water-soluble ions using Dionex DX-100 ion chromatograph. The size distribution of water-soluble inorganic ions in the atmospheric particulates appeared bimodal distribution, which were divided around $1-2{\mu}m$ into two groups. Mass site distribution of total ion in the coarse mode was found to be almost similar level during the sampling period, but fluctuations of mass size distribution in the fine mode were observed. Considering the mass size distribution of total ion concentrations for the respiratory deposition region, it was found that about 77.1% of total tons could be deposited in the alveolar region, and which dominated the daily variation of total ion concentrations. The concentration of total ions, which could be deposited in both the head region and the tracheobronchial region, was $3.95{\mu}g/m^3$, whereas that in the alveolar rerion was $13.28{\mu}g/m^3$. Dominant ions which could be deposited in the alveolar region were ${NO_3}{^-},\;{SO_4}^{2-}\;and\;{NH_4{^+}$, accounting for about 40%, 27% and 22% of the total ions, respectively. Although $K^+$ was approximately 3% of total ions, it was shown that most of this could be deposited in the alveolar region due to its high fraction of small size distribution originated from anthropogenic source of biomass burning. The presence of these ions in the fine mode may be of public health significance as they are very biologically harmful to health and have a high probability of being deposited in human lung tissue.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.773-774
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• 2013

• Journal of The Korea Institute of Healthcare Architecture
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• v.26 no.4
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• pp.7-14
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• 2020

Purpose: The purpose of this study is to provide basic information for the establishment of a Heavy Ion Therapy center by analyzing the cases of Heavy Ion Therapy devices, introducing the equipment and space composition of Heavy Ion Therapy equipments. Methods: This study is carried out by study the Heavy Ion Therapy, by figure out status of the installation of treatment centers around the world and by analyze the composition of Heavy Ion Therapy equipments and spaces through case studies. Results: The results of this study, which investigated the treatment of Heavy Ion Therapy and analyzed the plans of the five Heavy Ion Therapy centers, are summarized as follows. 1) Heavy Ion equipment requires a significant floor area. Vertical as well, many cross-sectional areas need to be secured for the construction of a delivery system. The Heavy Ion Therapy device should be built as a shielded wall because of the radiation leaking. Therefore, it is necessary to consist of a independent treatment center. 2) The size of Heavy Ion devices is getting smaller. Linac can be put into syncrotron. and the size of syncrotron, delivery system, and rotating-gantry is getting smaller. 3) Japan is often installed for treatment, and control rooms are integrated, while Europe has secured research space and each control room is separated. Implications: People are not familiar with the Heavy Ion Therapy. And the effectiveness of the treatment is not well promoted yet. Hopefully, more attention will be paid to the research involved in the Heavy Ion Therapy.

• Progress in Medical Physics
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• v.1 no.1
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• pp.91-95
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• 1990

The solid state detector system was constructed using commercially available rectifier diode for the assessment of quality assurance in radiotherapy. Dosimetry system which consists of the electrometer and the water phanton was used for measuring small field size scanning. The measured results, which had linearity in accordance with variation of radiation dose for gamma-ray of Co- 60 and 6 and 10MV photons of linear accelerator, showed quite linear characteristics within 1% error. The percent depth dose of 10MV photon of Mevatron KD linear accelerator was measured in small field size using diode, and the results were compared with that of using ion chambers. The results show that the difference of percent depth dose between the value of diode and that of ion chamber was negligible in large field size. However, in small size less than 4$\times$4cm, the difference of percent depth dose estimated by diode and ion chamber was 4.7% by extrapolation to 0$\times$0cm. Considering the smaller volume of diode than that of ion chamber, it might be more reliable to use diode for estimating percent depth dose. Above results suggest that diode can be used for routine check such as beam profile, flatness, symmetry and energy

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2960-2967
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• 2021

In this work, a new hardening model is proposed for the depth-dependent hardness of ion-irradiated polycrystals with obvious grain size effect. Dominant hardening mechanisms are addressed in the model, including the contribution of dislocations, irradiation-induced defects and grain boundaries. Two versions of the hardening model are compared, including the linear and square superposition models. A succinct parameter calibration method is modified to parametrize the models based on experimentally obtained hardness vs. indentation depth curves. It is noticed that both models can well characterize the experimental data of unirradiated polycrystals; whereas, the square superposition model performs better for ion-irradiated materials, therefore, the square superposition model is recommended. In addition, the new model separates the grain size effect from the dislocation hardening contribution, which makes the physical meaning of fitted parameters more rational when compared with existing hardness analysis models.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.94-106
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• 1995

A three-dimensional(3D) Monte Carlo simulator for boron ion implantation into <100>single-crystal silicon considering the mask structure has been developed to predict the mask-dependent impurity doping profiles of the implanted boron at low energies into the reduced area according to the trend of a reduction in the size of semiconductor devices. All relevant important parameters during ion implantation have been taken into account in this simulator. These are incident energy, tilt and rotation of wafer, orientation of silicon wafer, presence of native silicon dioxide layer, dose, wafer temperature, ion beam divergence, masking thickness, and size and structure of open window in the mask. The one-dimensional(1D) results obtained by using the 3D simulator have been compared with the SIMS experiments to demonstrate its capabilities and confirem its reliability, and we obtained relatively accurate 1D doping profiles. Through these 3D simulations considering the hole structure and its size, we found the mask effects during boron ion implantation process.

• New & Renewable Energy
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• v.19 no.2
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• pp.31-39
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• 2023

Salinity gradient energy can be generated from a mixture of water streams with different salt concentrations by using reverse electrodialysis (RED). In this study, we evaluated the effect of stack size and number of cell pairs on the energy efficiency and specific energy of the RED process. Additionally, we studied the prementioned parameters to maximize the power density of RED. The performance of the RED stack which used a patterned ion exchange membrane, was evaluated as a function of stack size and feed flow rate. Moreover, it was noted that an increase in stack size increased the ion movement through the ion exchange membrane. Furthermore, an increase in feed flow rate led to a reduction in the concentration variation, resulting in an increase in OCV and power density. The energy efficiency and specific energy for 100 cells in the 10 × 10 cm² stack were the highest at 12% and 0.05 kWh/m³, respectively, while the power density from 0.33 cm/s to 5 × 5 cm² stack was the highest at 0.53 W/m². The study showed that the RED performance can be improved by altering the size of the stack and the number of cell pairs, thereby positively affecting energy efficiency and specific energy.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.530-536
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• 2000

During the grain growth of the PZT thin films by selective nucleation method using PZT seed, it was found that the grain size was saturated with the annealing temperature. The saturation of grain size was analyzed by the interfacial energy which appeared during the crystallization. The factors affecting the saturation of grain size were found to be the interfacial energy between perovskite phase and pyrochlore phase, and PZT thin film and the bottom Pt electrode. When the ion damage was introduced to the grain-size saturated PZT thin films, further lateral growth was observed. Pt bottom electrode thickness was changed to control the interfacial energy between the PZT thin film and the Pt bottom electrode. When Pt thickness was increased, the grain size was also increased, because the lattice parameter of Pt films was increased with the thickness of the Pt films. The incubation time of nucleation was increased with the amount of the ion damage on the Pt films.