• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1273-1279
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• 2016

Production of iodine-131 by neutron activation of tellurium in tellurium dioxide ($TeO_2$) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gaswelding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ${\leq}10^{-4}mbr.L/s$, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to $600^{\circ}C$ with the appearance of deformations on lids beyond $450^{\circ}C$. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes-convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from4 hours of irradiation at a power level of 0.5MWup to 35 hours (7 h/d for 5 days a week) at 1.5MW. The results showthat the irradiated targets are tight because no iodine-131 was released in the atmosphere of the reactor building and in the reactor cooling water of the primary circuit.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.415-423
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• 2016

Numerous studies have been made on the negative effects of online games, as the negatives effects of the usage of online games have been recognized as social issues. However, this is a study on the positive functions of online gaming; more specifically, on how the guild activities on online games affect the user's leadership. This study has conducted in-depth interviews with online games, and drew the result using Giorgi's phenomenological analysis as for the methodology. 3 people participated in the research - a high school student, a university student, and an adult office worker - all of whom with experiences of guild leading on online games. To achieve the goal of this study, this study based the subjects' experience to analyze how online game guild activities have affected leadership on the subjects' real lives. As a result, timidity turned into initiation; not only leadership, but also decision making ability and coworking ability, as well as problem solving ability have shown improvement. Through this study, one can see that among the elements of online game, experience in guild activities is providing opportunities for enhancing leadership and possibilities for improving various other abilities. I hope more researchers continue studying interesting and diverse powers of online games based on this study.

• Korean Journal of Materials Research
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• v.7 no.12
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• pp.1063-1069
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• 1997

For me1t-spun Fe-Nd-C alloys, variation of phase development and magnetic properties with the variety of alloy compositions and production conditions were investigated. To find out whether hard magnetic $Fe_{14}Nd_2C$ is crystallized direct1y from the melt by rapid quenching, the phase development of the as-spun ribbons spun at various speed was a1so studied. For the ribbons spun at 10m/s, ${\alpha}-Fe$ was the primary crystallization phase followed by the secondary $Fe_{17}Nd_2C$. At 20m/s ${\alpha}-Fe$ was suppressed so that the primary $Fe_{17}Nd_2C$ coexisted with the secondary ${\alpha}-Fe$ and the amorphous phase. Above 30m/s the ribbons were a1most amorphous, and the amorphization was complete at 40m/s. $Fe_{14}Nd_2C$ therefore was not found in as-spun state but obtained after heat treating the ribbons. The effective temperature range ($700{\sim}900^{\circ}C$) in which $Fe_{14}Nd_2C$ can be obtained was wider than that of a cast alloy. An alloy made with the wheel speed of 20 or 30m/s yielded higher coercivities after heat treatment. In iron-rich Fe-Nd-C, the composition range in which a high coercivity (more than 10kOe) is expected is narrow, i.e., 77~78 Fe and 7~8 C(at.%).

• Journal of Korean Association for Spatial Structures
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• v.7 no.2 s.24
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• pp.105-114
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• 2007

Large span spaces have been widely used for various purposes including sports events in other countries. Due to increasing demands on multi-purpose use of such spaces, recently built large span sport facilities such dome stadiums have been required to accommodate sport events as well as performing events. Also, retractable ceilings and/or walls were generally adopted in those spaces for providing various event conditions. It seems obvious that the openings between diffuse fields and free field may cause difficulties in the acoustic design of such spaces In the present work, the acoustic characteristics of non-diffuse field has been investigated using 1/10 acoustic scale models. It was found that RTs at low- and mid-frequencies decayed faster than those at high-frequencies as the percentage of opening area increased. The decay rate of RTs at high frequencies were not influenced by increasing the area of an opening. Also high dependence of EDT on the percentage of opening area was observed at all frequency range. D50 was not improved by increasing the area of an opening up to 12.5% and then sharply increased. The application of Schroeder integration to evaluate the reverberation charateristics of coupled spaces may not be proper, since non-exponential decay process with double or triple decays of those spaces can not be properly defined. EDT seems more appropriate to predict reverberation at the early acoustic design stage of acoustically coupled spaces.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.1
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• pp.51-58
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• 2013

As it is changing into aging society, rehabilitation, welfare and sports industry markets are being expanded fast. Especially, the field of vital signals interface to control welfare instruments like wheelchair, rehabilitation ones like an artificial arm and leg and general electronic ones is a new technology field in the future. Also, this technology can help not only the handicapped, the old and the weak and the rehabilitation patients but also the general public in various application field. The commercial bio-signal measurement instruments and interface systems are complicated, expensive and large-scaled. So, there are a lot of limitations for using in real life with ease. this thesis proposes a wireless transmission interface system that uses EMG(electromyogram) signals and a control module to manipulate hardware systems with portable size. We have designed a hardware module that receives the EMG signals occurring at the time of wrist movement and eliminated noises with filter and amplified the signals effectively. DSP(Digital Signal Processor) chip of TMS320F2808 which was supplied from TI company was used for converting into digital signals from measured EMG signals and digital filtering. We also have used PCA(Principal Component Analysis) technique and classified into four motions which have right, left, up and down direction. This data was transmitted by wireless module in order to display at PC monitor. As a result, the developed system obtains recognition success ratio above 85% for four different motions. If the recognition ratio will be increased with more experiments. this implemented system using EMG wrist direction signals could be used to control various hardware systems.

• Journal of Korean Academy of Nursing
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• v.3 no.2
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• pp.111-119
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• 1973

The purpose of this study was to determine whether or not the delivery of health services effects the health knowledge of the recipients of that service. 10 was hypothesized that the practical application of theory, though health services rendered by public health nursing students during their field experiences. would have a positive relationship with the quantity and quality of health knowledge of the female population of a given community. In April 1970, ninety five women(between an age 15-49) from Koyang-Gun were interviewed regarding their knowledge and attitudes in four areas of health: maternal health, child health. family planning and tuberculosis prevention. After 11 years(Nov. l971), during which time the women received home visits by student nurses, the women were again interviewed using the original questionnaire. Additionally, they were asked where they had received information about each question. During the 1$\frac{1}{2}$ year period the visits were made by a total of 112 students. They visited the community twice a week. The result were as follows: Maternal health There was marked improvement in the knowledge of specific aspects of maternal health such as the proper instruments needed for cutting the cord and nutritional precaution of pregnancy (p<0.05). In each case 42.0 percent of more of this knowledge was attributed to information gained from the nursing students. However even after the nursing students'visits, the knowledge of other general areas of maternal remained poor. Child health There were increases in the knowledge of the respondents for the time to supplement breast feeding and for time to wean infants (p<0.05). In each case 35.0 percent or more of this information was attributed to the student. The increase in knowledge regarding types of immunization was more often attributed to the clinic nurse than to the nursing students. Knowledge of the necessity of booster immunization was poor both before and after the visits by the nursing students. Family planing There were significant increases in correct information regarding the time of I.U.D. insertion (P<0.05) and method of taking the oral pill (P<0.05). More than 42.0 percent of the increase was attributed to the nursing students'visits. However there was a slight decrease in correct information about concept of family planning. Tuberculosis There was a general lack of improvement in all areas concerned with tuberculosis. Two thirds of the respondents felt tuberculosis was hereditary and did not know what B.C.G. was. From this study, it could be concluded that in specific area the health knowledge of the female population studied was positively effected by the visits of the nursing students. The study also, suggests, however, that there was a marked unevenness in the overall increase in health knowledge. This raises serious questions which require further research. Suggested areas for further research are (1) Adequacy of the course content preparing nurses for the field experience. (2) A public health nursing manual for student reference. (3) Where and when specific aspects of health can be taught most effectively.

• Korean Journal of Optics and Photonics
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• v.31 no.2
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• pp.59-70
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• 2020

We discuss a modified numerical model based on the Monte Carlo radiative transfer (MCRT) method, i.e., the MCRT matrix method, for the analysis of atmospheric scattering effects in three-dimensional flash LIDAR systems. Based on the MCRT method, the radiative transfer function for a LIDAR signal is constructed in a form of a matrix, which corresponds to the characteristic response. Exploiting the superposition and convolution of the characteristic response matrices under the paraxial approximation, an extended computer simulation model of an overall flash LIDAR system is developed. The MCRT matrix method substantially reduces the number of tracking signals, which may grow excessively in the case of conventional Monte Carlo methods. Consequently, it can readily yield fast acquisition of the signal response under various scattering conditions and LIDAR-system configurations. Using the computational model based on the MCRT matrix method, we carry out numerical simulations of a three-dimensional flash LIDAR system operating under different atmospheric conditions, varying the scattering coefficient in terms of visible distance. We numerically analyze various phenomena caused by scattering effects in this system, such as degradation of the signal-to-noise ratio, glitches, and spatiotemporal spread and time delay of the LIDAR signals. The MCRT matrix method is expected to be very effective in analyzing a variety of LIDAR systems, including flash LIDAR systems for autonomous driving.

• 한국과학기술학회:학술대회논문집
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• 2015.12a
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• pp.247-278
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• 2015

Recently, as DNR prevails more and more in Korea, discussions regarding meaningless medical life-sustaining-treatment (LST) intensified. Some of the Supreme Court decisions are even discussed in mass media, causing public debates. These cases tell us that, as life-sustaining medical technologies are highly developed, more sociological and policy-related analyses are needed on them. Firstly, this study will review 40 previous studies that analyze recent discussions in Korea about LST. Secondly, this study also shows that in bioethical and policy-related perspectives, governance about LST calls for a new implications regarding thanatoethics and thanatopolitics. In this new theoretical framework, death with dignity (DwD) can be understood as a process of giving back the thanatopower to the subject who chooses his way of ending based on his sound and free will. Thirdly, some of the new LST or resuscitation technologies such as automated external defibrillators (AED) are developed in RRI framework. However, if subjects themselves choose not to apply those technologies on them, as in the case of DNR (do not resuscitate) vows, meaning of developing such technologies are to be questioned. But currently such questions regarding the limitations of RRI are seldom asked. I argue that in order to properly apply RRI framework on existing technology, we also need to consider these points.

• Journal of Sensor Science and Technology
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• v.6 no.5
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• pp.369-375
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• 1997

$V_{2}O_{5}/ThO_{2}/Pd$-doped $SnO_{2}$ sensor has a good selectivity and stability to CO at high sensor temperature of about $500^{\circ}C$, and shows rapid response. In particular, many kinds of interference gases, such as $NO_{x}$, $C_{3}H_{8}$, $CH_{4}$ and $SO_{2}$ have been found to give only a slight influence on the sensor selectivity to CO gas sensitivity by doped $V_{2}O_{5}$ (3.0 wt.%). For the sensor we used well-known thick film technological route with $V_{2}O_{5}$(3.0 wt.%), Pd(1.0 wt.%) and $ThO_{2}$(l.5 wt.%) as catalytic materials. In the case of mixed $NO_{x}$-CO gases, as combustion exhaust gas, only CO detection by $SnO_{2}$ type semiconductor sensor is generally very difficult because of $NO_{x}$ interference. The developed sensors can use to measure the exhausting gas of the automobile or the boiler for the Air-to-Fuel ratio control.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.84-87
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• 2008

In this research, we screened for glucosyltransferase (GTase) inhibitors that effectively prevent the dental caries from 420 kinds of boiled water extracts of herbs and wild plants and searched for GTase inhibitory activities. Among them, 13 kinds of hot water extracts had high GTase inhibitory activities and especially, we focused on Foeniculum vulgare which showed the highest inhibitory activity on GTase. The boiled water extract of F. vulgare was stable at high temperature and showed as a mixed type of competitive and uncompetitive inhibition kinetic behavior. It did not have antibacterial effect on Streptococcus mutans and had inhibitory activity on GTase. Specially, in the clinical trial, the group treated by boiled water extract of F. vulgare showed more decrease of plague index at 4.8 point than untreated group. These results suggested that boiled water extract of F. vulgare can effectively suppress the plague formation as it inhibits the GTase activity.