• Transactions on Electrical and Electronic Materials
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• v.11 no.6
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• pp.275-278
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• 2010

We have examined the Ferroelectric properties of $PbZr_{0.4}Ti_{0.6}O_3$ (PZT) grains by monitoring the surface potential through the utilization of Kelvin force microscopy. Hysteretic and time dependent behaviors of small and large grains were compared with each other. The smaller grain yields had smaller values of surface potential. However, the normalized voltage versus surface potential behavior indicates that the smaller grains became saturated earlier with respect to the writing voltages than did the larger grains. On the other hand, the surface potential hysteresis loop obtained from the smaller grains showed a similar shape to what might be obtained from a Zr rich PZT film. In contrast the hysteresis loop of the larger grain looks like that obtained from a Ti-rich film. In addition, the time dependent behaviors of the smaller grains also revealed a better response than the response of larger grains. The overall ferroelectric properties of the smaller grains seem better than corresponding properties for larger grains. The Ti/Zr ratio of the PZT film which was examined in this study was 60/40.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.6
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• pp.413-420
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• 2008

The unsteady heat release characteristics play a significant role in combustion instabilities observed in low emissions gas turbine combustors. Such combustion instabilities are often caused by coupling mechanisms between unsteady heat release rates and acoustic perturbations. A generalized model of the turbulent flame response to acoustic perturbations is analytically formulated by considering a distributed heat release along a curved mean flame front and using the flame's kinematic model that incorporates the turbulent flame development. The effects of the development of flame speed on the flame transfer functions are examined by calculating the transfer functions with a constant or developing flame speed. The flame transfer function due to velocity fluctuation shows that, when a developing flame speed is used, the transfer function magnitude decreases faster with Strouhal number than the results with a constant flame speed at low Strouhal numbers. The flame transfer function due to mixture ratio fluctuation, however, exhibits the opposite results: the transfer function magnitude with a developing flame speed increases faster than that with a constant flame speed at low Strouhal numbers. Oscillatory behaviors of both transfer function magnitudes are shown to be damped when a developing flame speed is used. Both transfer functions also show similar behaviors in the phase characteristics: The phases of both transfer functions with a developing flame speed increase more rapidly than those with a constant flame speed.

• Korean Journal of Pharmacognosy
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• v.5 no.3
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• pp.159-166
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• 1974

The Yellow needle crystal was isolated from Atractylis Rhizoma, having mp $124{\sim}126^{\circ}C$(decomp.), the chemical composition $C_{16}H_{21}N_{3}O_{6}$, and its m.w. 251. The pharmacological actions of this alkaloid were studied by various psycopharmacological experiments. 1) In order to see the effect of this Atractylis(=At.) alkaloid on gross general behaviors in mice, a behavioral analysis experiment was adapted. The occurrence number of sleep and lying in At. alkaloidal animals with the doses 10mg/kg or 20mg/kg was increased but the number of jumping, exploration, rearing and defecation was significantly decreased than those of placebo. 2) The effect of the At. alkaloid on unlearned emotional behaviors of mice was studied with an open-field method. The At. alkaloidal groups with the doses 20mg/kg or 30mg/kg showed less often the frequency of locomotion than that of placebo. 3) To know the effect of the At. alkaloid on the learning, a standard water maze experiment and conditioned avoidance response were conducted. As compared to placebo control, the aquisition rate of the maze learning in the alkaloidal mice with the dose of 10mg/kg or 20mg/kg was significantly impaired and the speed of swimming was also signficantly delayed. In the conditioned avoidance response, the extinction performances of the alkaloidal rats with doses of 20mg/kg or 30mg/kg did not differ significantly than that of placebo.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.451-456
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• 2011

To ensure structural integrity of membrane type LNG tank, the rational assessment of the sloshing impact responses of tank structures should be preceded. The sloshing impact pressures acting on the insulation system of LNG tank are typical irregular loads and the resulting structural responses show very complex behaviors accompanied with fluid structure interaction. So it is not easy to estimate them accurately and immense time consuming calculation process would be necessary. In this research, a simplified method to analyse the dynamic structural responses of LNG tank insulation system under pressure time histories obtained by sloshing model test or numerical analysis was studied. The proposed technique based on the concept of linear combination of the triangular response functions which are the transient responses of structures under the unit triangular impact pressure acting on structures. The validity of suggested method was verified through the example calculations and applied to the dynamic structural response analysis of a real Mark III membrane type insulation system using the sloshing impact pressure time histories obtained by model test.

• Journal of Ocean Engineering and Technology
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• v.20 no.3 s.70
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• pp.54-60
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• 2006

For optimal design of a deep-sea ocean mining collector system, based on self-propelled mining vehicle, it is imperative to develop and validate the dynamic model of a tracked vehicle traveling on soft deep seabed. The purpose of this paper is to evaluate the fidelity of the dynamic simulation model by means of response surface methodology. Various statistical techniques related to response surface methodology, such as outlier analysis, detection of interaction effect, analysis of variance, inference of the significance of design variables, and global sensitivity analysis, are examined. To obtain a plausible response surface model, maximum entropy sampling is adopted. From statistical analysis and prediction for dynamic responses of the tracked vehicle, conclusions will be drawn about the accuracy of the dynamic model and the performance of the response surface model.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.600-606
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• 2019

Studies on the application of the lead rubber bearing (LRB) isolation system to nuclear power plants are being carried out as one of the measures to improve seismic performance. Nuclear power plants with isolation systems require seismic probabilistic safety assessments, for which the seismic fragility of the structures, systems, and components needs be calculated, including for beyond design basis earthquakes. To this end, seismic response analyses are required, where it can be seen that the behaviors of the isolation system components govern the overall seismic response of an isolated plant. The numerical model of the LRB used in these seismic response analyses plays an important role, but in most cases, the extreme performance of the LRB has not been well studied. The current work therefore develops an extreme nonlinear numerical model that can express the seismic response of the LRB for beyond design basis earthquakes. A full-scale LRB was fabricated and dynamically tested with various input conditions, and test results confirmed that the developed numerical model better represents the behavior of the LRB over previous models. Subsequent seismic response analyses of isolated nuclear power plants using the model developed here are expected to provide more accurate results for seismic probabilistic safety assessments.

• Journal of the Korean Society of Safety
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• v.24 no.3
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• pp.71-78
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• 2009

During a learning process, a human being is assumed to experience knowledge-based behaviors, rule-based behaviors, and skill-based behaviors sequentially if Rasmussen was right. If any psycho-physiological symptom to those different levels can be obtained, it can be useful as a measure whether a human being is fully trained and has gotten a skill in his work. Therefore, this study aimed to draw relationships between human performance measures and psycho-physiological measures while committing a computer-simulated pointing task by utilizing the power spectrum technique of EEG data, especially with the ratio of relative beta-to-alpha band power. The result showed that, during correct responses, the ratio came to stabilize as all the performance data went stable. However, response time was not a simple linear function of task difficulty level only, but a joint function of task characteristics as well as behavior levels. Comparing relative band power ratios from errors and correct responses, activated states of one's brain could be explained, and characteristics of the task could understood. To tell that of pointing task, correlations around C3, C4, P3, P4 and 01, 02 area were significant and high in correct response cases whereas most correlation coefficients went down in error cases standing for imbalance of psycho-motor functions. Though task difficulty was the only one factor that could influence on relative band power ratio with statistical significance, it should be comprehended to mean a different way of expression indicating task characteristics since at least error-some situation could be explained with the help of relative band power ratio that absolute band power failed.

• Journal of Preventive Medicine and Public Health
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• v.54 no.6
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• pp.431-440
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• 2021

Objectives: The aim of this study was to predict rabies protective behaviors (RPB) based on protection motivation theory (PMT) among fourth-grade students at schools in Chonburi Province, Thailand. Methods: This cross-sectional study was conducted from December 2020 to February 2021. A multistage sampling technique was used for sample selection. The questionnaire was divided into socio-demographic data and questions related to PMT and RPB. Descriptive statistical analysis was conducted using the EpiData program and inferential statistics, and the results were tested using the partial least squares model with a significance level of less than 5%. Results: In total, 287 subjects were included, of whom 62.4% were girls and 40.4% reported that YouTube was their favorite media platform. Most participants had good perceived vulnerability, response efficacy, and self efficacy levels related to rabies (43.9, 68.6, and 73.2%, respectively). However, 54.5% had only fair perceived severity levels related to rabies. Significant positive correlations were found between RPB and the PMT constructs related to rabies (β, 0.298; p<0.001), and the school variable (S4) was also a predictor of RPB (β, -0.228; p<0.001). Among the PMT constructs, self efficacy was the strongest predictor of RPB (β, 0.741; p<0.001). Conclusions: PMT is a useful framework for predicting RPB. Future RPB or prevention/protection intervention studies based on PMT should focus on improving self efficacy and response efficacy, with a particular focus on teaching students not to intervene with fighting animals. The most influential PMT constructs can be used for designing tools and implementing and evaluating future educational interventions to prevent rabies in children.

• The Korean Journal of Pain
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• v.35 no.2
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• pp.173-182
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• 2022

Background: Neurokinin-1 (NK1) and calcitonin gene-related peptide (CGRP) play a vital role in pain pathogenesis, and these proteins' antagonists have attracted attention as promising pharmaceutical candidates. The authors investigated the anti-nociceptive effect of co-administration of the CGRP antagonist and an NK1 antagonist on pain models compared to conventional single regimens. Methods: C57Bl/6J mice underwent sciatic nerve ligation for the neuropathic pain model and were injected with 4% formalin into the hind paw for the inflammatory pain model. Each model was divided into four groups: vehicle, NK1 antagonist, CGRP antagonist, and combination treatment groups. The NK1 antagonist aprepitant (BIBN4096, 1 mg/kg) or the CGRP antagonist olcegepant (MK-0869, 10 mg/kg) was injected intraperitoneally. Mechanical allodynia, thermal hypersensitivity, and anxiety-related behaviors were assessed using the von Frey, hot plate, and elevated plus-maze tests. The flinching and licking responses were also evaluated after formalin injection. Results: Co-administration of aprepitant and olcegepant more significantly alleviated pain behaviors than administration of single agents or vehicle, increasing the mechanical threshold and improving the response latency. Anxiety-related behaviors were also markedly improved after dual treatment compared with either naive mice or the neuropathic pain model in the dual treatment group. Flinching frequency and licking response after formalin injection decreased significantly in the dual treatment group. Isobolographic analysis showed a meaningful additive effect between the two compounds. Conclusions: A combination pharmacological therapy comprised of multiple neuropeptide antagonists could be a more effective therapeutic strategy for alleviating neuropathic or inflammatory pain.

• The Journal of Korean Academic Society of Nursing Education
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• v.30 no.3
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• pp.222-231
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• 2024

Purpose: This study is to explore the antecedent factors of daycare teacher behaviors concerning the eye health of preschool children by applying an extended parallel process model. Methods: Focus group interviews were conducted with ten daycare center teachers on September 4 and 14, 2023. A data analysis was performed according to the content analysis method by clustering the data into the four categories: the two threat factors of severity and susceptibility and the two efficacy factors of self-efficacy and response-efficacy. Results: Daycare center teachers' perception of the severity of eye health problems in preschool children was high in relation to eye trauma, but it was recognized that viewing the electronic devices were of a less severe because symptoms were not noticed in a short period of time. They also showed low susceptibility because they were not sufficiently interested in the eye health hazard behaviors of preschool children. The self-efficacy of daycare center teachers was low because this was a lack of knowledge about symptoms of eye problems. However, they recognized that eye health activities performed in the preschool age could prevent negative eye health outcomes, thus showing a high response efficacy. Conclusion: In the future, it is necessary to increase the sensitivity and engagement of daycare center teachers concerning with the eye health of preschool children and to increase their self-efficacy. It will also be necessary to develop various interventions to improve eye health for preschool children that can be implemented by daycare center teachers.