• Science of Emotion and Sensibility
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• v.16 no.4
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• pp.509-516
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• 2013

As the visual fatigue induced by 3D visual stimulation has raised some safety concerns in the industry, this study aims to quantify the visual fatigue through the means of measuring the facial temperature changes. Facial temperature was measured for one minute before and after watching a visual stimulus. Whether the visual fatigue has occurred was measured through subjective evaluations and high cognitive tasks. The difference in the changes that occurred after watching a 2D stimulus and a 3D stimulus was computed in order to associate the facial temperature changes and the visual fatigue induced by watching 3D contents. The results showed significant differences in the subjective evaluations and in the high cognitive tasks. Also, the ERP latency increased after watching 3D stimuli. There were significant differences in the maximum value of the temperature at the forehead and at the tip of the nose. A previous study showed that 3D visual fatigue activates the sympathetic nervous system. Activation of the sympathetic nervous system is known to increase the heart rate as well as the blood flow into the face through the carotid arteries system. When watching 2D or 3D stimuli, the sympathetic nervous system activation dictates the blood flow, which then influences the facial temperature. This study is meaningful in that it is one of the first investigations that looks into the possibility to measure 3D visual fatigue with thermal images.

• Journal of Korean Elementary Science Education
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• v.19 no.1
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• pp.157-170
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• 2000

The purpose of this study is to survey the instructional state of the unit 'Small Living Things' in the Elementary School Science. for this study, 100 teachers were surveyed on teaching-learning practices. More specifically, questions were asked on the degree of accomplishing instruction objectives, frequency of field . study, experimental preparation, alternative instructional methods, amount of preparation, availability of reference books for teachers and availability of information materials on the Kwangju region. Our results show that teachers find the objectives related to the collection of living things for class experiments and the task of growing and observing them the most difficult to accomplish. It was reported that 38% of teachers have actually conducted field trips. The obstacles listed in going out on field study range from lack of knowledge of appropriate places, lack of time, to safety concerns. The most difficult problem in teaching this unit was preparing proper instructional materials, regardless of teacher's gender, career, and interest. Most respondents let children provide the experimental subjects. Teachers with collection experience tend to provide for the experimental materials themselves. Our Analysis also reveals that more than 70% of the respondents do not have adequate knowledge of the species dealt with in the unit. Gender, career, and interest area of the teachers did not make any difference (p< .05). In the case that proper experimental subjects have not been prepared, VTR, textbooks, and charts were reported as the most frequently used alternative instruction aids. The level of content and amount of knowledge contained in this unit were found to be appropriate. Information on instruction materials and experiment-observation were obtained through the teaching manual or periodicals (58%), information materials on the region(20%), and fellow teachers (12%). Reference books for teachers and materials on the region are perceived to be inadequate in order of importance in the areas of preparation method, level-wise learning guide, experimental observation, and information on species covered in text. Overall, it was judged that the highest concern was with obtaining experimental materials, and teacher's reference books and materials on the region need to be reinforced to allow teachers to more fully utilize them. Development and distribution of proper instruction-learning materials to the children's level is also required.

• Journal of the Korean Institute of Gas
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• v.5 no.3 s.15
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• pp.45-50
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• 2001

Open rack vaporizer (ORV) has been used in liquefied natural gas (LNG) receiving terminal in order to vaporize LNG into natural gas (NG) by heat exchange with seawater The U-type ORV which had been operated with seawater for 14 years is one of the important utilities of the gas production and the weld part of tube connected with header_ pipe had experienced many corrosion problems. To elucidate the cause of corrosion at weld part of vaporizer tube, corrosion potentials were compared by parts. This study concerns on the measurement of corrosion pit depth using non-destructive method and the evaluation of stress distribution in an aspect of safety with finite element analysis. In order to confirm the reliability of galvanic corrosion between weld parts and base metal, the measurement of corrosion potential by parts was conducted for 20 minutes in 3.5$\%$(wt.) NaCl solution. Many non-destructive methods were tried to measure the remaining thickness of vaporizer tube at fields. For general corrosion, tangential radiography test was confirmed as an effective method. In case of a fine corrosion pit, the shape of corrosion pit was reproduced using surface replication method. From collected data, stress distributions were quantitatively evaluated with 2-dimensional finite element method and the diagnostic evaluation on internal pressure of the U-type vaporizer could be made.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.103-105
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• 2003

After fifteen years of development, Magnetic Resonance (MR) technology for human imaging and spectroscopy is reaching a refined state with FDA approved 3T clinical products from Siemens, GE, and Philips. Broker has cleared CE approval with a 4T system. Varian supports a 4T system platform as well. Shielded magnets are standard at 3T from GE, Oxford, Magnex, and IGC. A shielded 4T whole body magnet is available from Oxford. Stronger switched gradients and dynamic shim coils, desired at any field, areespecially useful at higher static magnetic fields B0. In addition to the higher currents required for higher resolution slice or volume selection afforded by higher SNR, whole body gradient coils will be driven at increasing slew rates to meet the needs of new cardiac applications and other requirements. For example 3T and 4T systems are now being equipped with 2kV, 500A gradient coils and amplifiers capable of generating 4G/cm in 200msec, over a 67+/-cm bore diameter. High field EPI applications require oscillation rates at 1 kHz and higher. To achieve a benchmark 0.2 ppm shim over a 30cm sphere in a high field magnet, at least four stages of shimming need to be considered. 1) A good high field magnet will be built to a homogeneity spec. falling in the range of 100 to 150 ppm over this 30cm spherical "sweet spot" 2) Most modern high field magnets will also have superconducting shim coils capable of finding 1.5 ppm by their adjustment during system installation. 3) Passive ferro-magnetic shimming combined with 4) active, high order room temperature shim coils (as many as five orders are now being recommended) will accomplish 0.2 ppm over the 30cm sphere, and 0.1 ppm over a human brain in even the highest field magnets for human studies. Safety concerns for strong, fast gradients at any B0 field include acoustic noise and peripheral nerve stimulation. One or more of the mechanical decoupling methods may lead to quieter gradients. Patient positioning relative to asymmetric or short gradient coils may limit peripheral nerve stimulation at higher slew rates. Gradient designs combining a short coil for local speed and strength with a longer coil for coverage are being developed for 3T systems. Local gradients give another approach to maximizing performance over a limited region while keeping within the physiologically imposed dB0/dt performance limits.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.595-601
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• 2014

The microstructures of NATM were examined by SEM, FT-IR spectra, tensile properties, mole % of [NCO/OH], and particle size analyzer. Growing concerns in the environment-friendly industries have led to the development of solvent-free formulations that can be cured. We had synthesized NATM(New Austria Tunnel Method) resin having the ability to protect stainless steel against corrosion. Comparing with general NATM resin and coatings, this resin that synthesized with polyurethane and epoxy was highly stronger in intensity and longer durability. Hybrid resin was composed of polyols, MDI, epoxy, silicone surfactant, catalyst and crosslink agent, and fillers. Moreover, fillers such as fume silica not only accelerated the curing rate but also improved the physical property as thermal barriers. The rigid segments of synthetic resin in mechanical properties were due to fume silica and the increase the mole% of [NCO/OH] for corrosion protection. In conclusion, the hybrid resin microstructure with crosslink agent and fume silica are good material for thermosetting coating of metal substrates such as stainless steel.

• Toxicological Research
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• v.34 no.3
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• pp.221-229
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• 2018

Tenofovir nanoparticles are novel therapeutic intervention in human immunodeficiency virus (HIV) infection reaching the virus in their sanctuary sites. However, there has been no systemic toxicity testing of this formulation despite global concerns on the safety of nano drugs. Therefore, this study was designed to investigate the toxicity of Tenofovir nanoparticle (NTDF) on the liver and kidney using an animal model. Fifteen adult male Sprague-Dawley (SD) rats maintained at the animal house of the biomedical resources unit of the University of KwaZulu-Natal were weighed and divided into three groups. Control animals (A) were administered with normal saline (NS). The therapeutic doses of Tenofovir (TDF) and nanoparticles of Tenofovir (NTDF) were administered to group B and C and observed for signs of stress for four weeks after which animals were weighed and sacrificed. Liver and kidney were removed and fixed in formal saline, processed and stained using H/E, PAS and MT stains for light microscopy. Serum was obtained for renal function test (RFT) and liver function test (LFT). Cellular measurements and capturing were done using ImageJ and Leica software 2.0. Data were analysed using graph pad 6, p values < 0.05 were significant. We observed no signs of behavioural toxicity and no mortality during this study, however, in the kidneys, we reported mild morphological perturbations widening of Bowman's space, and vacuolations in glomerulus and tubules of TDF and NTDF animals. Also, there was a significant elevation of glycogen deposition in NTDF and TDF animals when compared with control. In the liver, there were mild histological changes with widening of sinusoidal spaces, vacuolations in hepatocytes and elevation of glycogen deposition in TDF and NTDF administered animals. In addition to this, there were no significant differences in stereological measurements and cell count, LFT, RFT, weight changes and organo-somatic index between treatment groups and control. In conclusion, NTDF and TDF in therapeutic doses can lead to mild hepatic and renal histological damage. Further studies are needed to understand the precise genetic mechanism.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.5
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• pp.380-387
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• 2014

Piper Alpha disaster drew attention to the damage likely to arise from explosions and fires on an offshore platform. And great concerns have been increased to prevent these hazards. Blast wall is one of the passive safety systems; it plays a key part of minimizing the consequences. However, a buckling due to explosion loads is a factor which can reduce the strength of blast wall. The buckling often occurs between web and flange at the center of blast wall. This study aims to find a solution for reinforcing its strength by installing a flat plate at the spot where the buckling occurs. First of all, ANSYS finite element method is adopted to numerically compute the structural resistance characteristic of blast wall by using a quasi-static approach. Sequentially, the impact response characteristics of blast wall are investigated the effect on thickness of flat plate by using ANSYS/LS-DYNA. Finally, pressure-impulse diagrams (P-I diagram) are presented to permit easy assessment of structural response characteristics of stiffened blast wall. In this study, effective use is made to increase structural intensity. of blast wall and acquired important insights have been documented.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.3
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• pp.11-19
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• 2009

Recently, concerns relating to the maintenance of large structures have been increased. In addition, the number of large structures that need to be evaluated for their structural safety due to natural disasters and structural deterioration has been rapidly increasing. It is common for the structural characteristics of an older large structure to differ from the characteristics in the initial design stage, and changes in dynamic characteristics may result from a reduction in stiffness due to cracks on the materials. The process of deterioration of such structures enables the detection of damaged locations, as well as a quantitative evaluation. One of the typical measuring instruments used for the monitoring of bridges and buildings is the dynamic measurement system. Conventional dynamic measurement systems require considerable cabling to facilitate a direct connection between sensor and DAQ logger. For this reason, a method of measuring structural responses from a remote distance without the mounted sensors is needed. In terms of non-contact methods that are applicable to dynamic response measurement, the methods using the doppler effect of a laser or a GPS are commonly used. However, such methods could not be generally applied to bridge structures because of their costs and inaccuracies. Alternatively, a method using a visual image can be economical as well as feasible for measuring vibration signals of inaccessible bridge structures and extracting their dynamic characteristics. Many studies have been conducted using camera visual signals instead of conventional mounted sensors. However, these studies have been focused on measuring displacement response by an image processing technique after recording a position of the target mounted on the structure, in which the number of measurement targets may be limited. Therefore, in this study, a model experiment was carried out to verify the measurement algorithm for measuring multi-point displacement responses by using a DIC (Digital Image Correlation) technique.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.2
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• pp.139-152
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• 2020

Objectives To explore the traffic injury patients' experience on health care utilization of Korean Medicine (KM) practice and perception of health care system for developing a Korean medicine clinical practice guideline (CPG) of traffic injuries by survey method. Methods Two hundred ten patients in suffering from traffic injuries were surveyed from September 1st, 2019 to January 31th, 2020 at 2 University Hospitals (Pusan National Korean Medicine Hospital and Kyung Hee Korean Medicine Hospital at Gangdong) and 1 Spine Specialty Hospital (Jaseng Hospital of Korean Medicine). A structured questionnaire of experience on health care utilization of KM practice and perception of health care system of was distributed to responders by visits and all data were statistically analysed. Results Survey results showed high satisfaction of patients with the experience of KM treatments in order of daoyin exercise (7.8±2.3), chuna manual therapy (7.7±4.0), pharmacoacupuncture (7.4±3.0) etc. Safety concerns were reported in 9.1% subjects and 205 (97.6%) patients answered that collaboration with KM and western medicine is necessary for patients with traffic injuries. For the patients' requirement for extending insurance coverage, the most required therapy was chuna manual therapy (57.5%) and pharmacoacupuncture (42.0%). Conclusions This study presented the realistic patient-centered perception of KM practice and health care system in Korea. These results will provide basic data to be reflected in the process of adaptation for the revision of Korean Medicine CPG for traffic injuries.

• Child Health Nursing Research
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• v.8 no.4
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• pp.435-448
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• 2002

Accidents are important causes of death and disability in children. They also have enormous financial implications. Young children become an victim of accidents easily because of their physical fragileness and their coping behavior being vulnerable to any actions taken by accidents. Once they have a accident, the children whose not fully developed, suffer from devastating long-term after-effects. Lee, Lee, Kang and Han(1995) reported that ninety percent of accidents can be prevented. But there is no national system to manage, evaluate and analyse the information about child accidents, even though it is necessary for accident prevention policies and health promotion of the general public. The purpose of the study was to determine how often children have accidents and define the accident prevention strategies in children. The investigator conducted a descriptive study by performing the surveys, interviews, and workshops for the 2,458 young children, 10 teachers, and 1,494 parents. The data collection for the study began on September 2000 and completed on April 20, 2001. The analysis of the data was done with Window SPSS 10.0 for descriptive statistics. Among those children, 1,298 children(52.8％) injured from accidents. The children who had accident answered that they injured from traffic accident(27.3％), inside the home(26.3％), on the playground(17.0％), during playtime(13.6％), in the school(5.9％) and food poisoning(7.1％). To define accident prevention strategies for the school children, the parents and the teachers who had a special interest in this topic formed a special task force under the guidance of the investigator. The team was charged to prepare the basis of content materials by identifying the problems, setting standards for the program, prioritizing the process, and selecting the methods of implementation and evaluation. Eight issues and concerns identified by the team were: 1)allowing young children to learn undesirable habits and behaviors that would bother others without knowing; 2) not guarding young children from car accident; 3)unattended accident at playground; 4) considering home places safe; 5)unattended accident at school. These issues were found to be coinciding with the actual child accident cases occurred recent years in Korea. Greater efforts are required to reduce unnecessary deaths and disability from childhood accidents. This study gave a very useful and important data to prepare accident prevention educational program and to prepare accident prevention strategies.