• Journal of the Korean Society of Safety
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• v.1 no.1
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• pp.41-49
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• 1986

Modern technological progress demands the use of materials at high temperature and high pressure. One of the most critical factors in considering such applications-perhaps the most critical one-is creep behavior. In this study the activation energy for the creep rupture (Qf) and the stress dependence of rupture time (n') have been determined during creep of Al 7075 alloy eve, the temporature range of $200^{\circ}C to 500^{\circ}C$ and stress range of 0.64 kgf/$\textrm{mm}^2$ to 9.55 kgf/$\textrm{mm}^2$, respectively, in order to investigate the creep-rupture property. Constant load creep tests were carried out in the enperiment At around the temperature $210^{\circ}C~390^{\circ}C$ and the stress level 1.53~9.55(kgf/$\textrm{mm}^2$), the stress dependence of rupture time(n') had the value of 6.6~6.78 but at 50$0^{\circ}C$, the value of 1.3. Besides at around the temperature of $200^{\circ}C~500^{\circ}C$ and under the stress level of 0.89~8.51 (kgf/$\textrm{mm}^2$), the activation energy for the creepprupture (Qf) was nearly equal to that of the volume self diffusion of pure aluminum (34Kca1/mo1e)

• Journal of the Korean Society for Heat Treatment
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• v.10 no.3
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• pp.198-208
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• 1997

The-steady-state creep mechanism and behavior of Zircaloy-4 used as cladding materials in PWR have been investigated in air environment over the temp, ranges from 600 to $645^{\circ}C$ and stress ranges from 4 to $7kg/mm^2$. The stress exponents for the creep deformation of this alloy, n were decreased 4.81, 4.71, 4.64, and 4.56 at 600, 615, 630 and $645^{\circ}C$, respectively; the stress exponents decreased with increasing the temperature and got closer to about 5. The apparent activation energies, Q, were 62.1, 60.0, 57.9 and 55.4 kcal/mole at stresses of 4, 5, 6, $7kg/mm^2$, respectively; the activation energies decreased with increasing the stress and were close to those of volume self diffusion of Zr in Zr-Sn-Fe-Cr system. In results, it can be considered that the creep deformation for Zircaloy-4 was controlled by the dislocation climb over the ranges of this experimental conditions. Larson-Miller parameter, P, for the crept specimens was obtained as P=(T+460)(logt,+23). The failure plane observed by SEM slightly showed up intergranular fracture at this experiment ranges. However, it was essentially dominated by the dimple phenomenon, which was a characteristics of the transgranular fracture.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.195-200
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• 1998

Since the neural network was introduced, significant progress has been made on data handling and learning algorithms. Currently, the most popular learning algorithm in neural network training is feed forward error back-propagation (FFEBP) algorithm. Aside from the success of the FFEBP algorithm, polynomial neural networks (PNN) learning has been proposed as a new learning method. The PNN learning is a self-organizing process designed to determine an appropriate set of Ivakhnenko polynomials that allow the activation of many neurons to achieve a desired state of activation that mimics a given set of sampled patterns. These neurons are interconnected in such a way that the knowledge is stored in Ivakhnenko coefficients. In this paper, the PNN model has been developed using the plasma enhanced chemical vapor deposition (PECVD) experimental data. To characterize the PECVD process using PNN, SiO$_2$films deposited under varying conditions were analyzed using fractional factorial experimental design with three center points. Parameters varied in these experiments included substrate temperature, pressure, RF power, silane flow rate and nitrous oxide flow rate. Approximately five microns of SiO$_2$were deposited on (100) silicon wafers in a Plasma-Therm 700 series PECVD system at 13.56 MHz.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.1
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• pp.13-24
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• 2010

Objectives : This study aimed to investigate the current job-related characteristics coordinators in East-West Collaborative Medical Practices(EWCMP) and to develop activation plans for them. Method : The participants were 51 personnel who were supporting EWCMP in the 28 institutions. Data were collected with self-administered questionnaires and analyzed with descriptive statistics. Results : The major role of the participants was educating and consulting patients(74.5%) and followed by supporting collaborating physician(70.6%). They assumed to be helpful to make the patients easy to use EWCMP(98%) and to give patients full information what they asked(96%). However, participants responded lack of adequate educational programs and role ambiguity as chief complaints(91.7%). They showed relatively high level of job importance(78.7points on 100points) and job satisfaction(72.8points on 100points). Coordinators were expected to have bachelor and more than 8 years clinical career, and communication skill. Conclusions : Coordinators have played key roles in giving information for the patients and coordinating EWCMP. However their roles and job description was not clear, and educational programs was insufficient as required. Therefore, it is needed to clarify their roles and job description and establish professional educational programs for supporting coordinators.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.364-370
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• 2008

Spinning detonations propagating in a circular tube were numerically investigated with a one-step irreversible reaction model governed by Arrhenius kinetics. The time evolution of the simulation results was utilized to reveal the propagation mechanism of single-headed spinning detonation. The track angle of soot record on the tube wall was numerically reproduced with various levels of activation energy, and the simulated unique angle was the same as that of the previous reports. The maximum pressure histories of the shock front on the tube wall showed stable and unstable pitch modes for the lower and higher activation energies, respectively. The shock front shapes and the pressure profiles on the tube wall clarified the mechanisms of two modes. The maximum pressure history in the stable pitch remained nearly constant, and the single Mach leg existing on the shock front rotated at a constant speed. The high and low frequency pressure oscillations appeared in the unstable pitch due to the generation and decay of complex Mach interaction on the shock front shape. The high frequency oscillation was self-induced because the intensity of the transverse wave was changed during propagation in one cycle. The high frequency behavior was not always the same for each cycle, and therefore the low frequency oscillation was also induced in the pressure history.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.1
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• pp.111-119
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• 2019

PURPOSE: The aim of this study was to determine how biofeedback training with Shaker exercise effects the activation of the cervical myocardial muscle in stroke with swallowing disorder. METHODS: From June 2018 to September 2018, 30 patients who were hospitalized at C hospital and K hospital in Daegu, and K hospital in Gumi were surveyed to meet the criteria for selection. The participants were classified into three groups, and Shaker exercise was applied three times a day, five times a week, for four weeks; visuoauditory biofeedback group (VABG), visual biofeedback group (VBG), and self-exercises group (SG). In addition, the suprahyoid muscle activity was performed three times (before intervention, after intervention, and after two weeks). RESULTS: The pre and post-test comparisons, revealed a significant difference between the three groups (p<.01); VABG had the highest suprahyoid muscle activity. The post-test and follow-up test produced similar results in, the three groups (p>.05). The mean comparison showed the smallest difference in VABG, indicating that muscle persistence was the best. CONCLUSION: Shaker exercise has an effect on suprahyoid muscle activation. Biofeedback training, which provides an input of multi-sensory information in swallowing disorder treatment is recommended because it has the greatest effect when combined with visuoauditory biofeedback.

• Journal of International Academy of Physical Therapy Research
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• v.12 no.2
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• pp.2338-2344
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• 2021

Background: The therapeutic exercise method using kinesiology taping (KT) has been reported to be effective in activating the suprahyoid muscle in healthy adults. However, its applicability and effectiveness are not known to the physically vulnerable elderly. Objectives: To investigate the effects of kinesiology taping on the activity of suprahyoid muscles in community-dwelling elderly people. Design: Repeated measure design. Methods: We enrolled 23 healthy elderly adults (age range 60-75 years) with no history of neurologic disease. Participants performed five consecutive spontaneous swallowing actions at 5-second intervals under three conditions (KT with 80% stretch, placebo-KT, and non-KT. Activation of the suprahyoid muscles during swallowing in the three conditions was measured using surface electromyography (sEMG). In addition, a 0-10 numerical rating self-report scale was used to evaluate the required effort and the resistance felt during swallowing. Results: KT with 80% stretch were significantly higher in sEMG mean value, peak value, required effort, and resistance felt during swallowing compared to other two conditions (P<.05, all). KT with 80% stretch required the most effort during swallowing and, consequently, has a positive effect on increasing suprahyoid muscle activation. Conclusion: Our results could be taken into consideration in therapeutic exercise method for suprahyoid muscle in dysphagia rehabilitation.

• Journal of Distribution Science
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• v.9 no.1
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• pp.5-15
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• 2011

Research regarding corporate associations in marketing has generally been approached using the association theory. However, limited research investigates the effect of corporate associations on consumer loyalty to individual brands by examining the role of self connectedness with a corporate image. The activation of behavior-related constructs can influence individuals' behaviors without their intention or conscious awareness. A recently developed body of research suggests that self connection can play an important role in affecting subsequent behaviors. Although these effects have received considerable attention, the set of mechanisms involved in self connectedness and loyalty to individual brands is not clear. An active self account in which associative constructs can affect behavior by temporarily altering the active self-concept may lead to behavior or evaluation. If the exposure to a corporate brand can induce consumers' cognitive associations and goal-primed effects through the role of active self accounting, the connectedness between the consumer's self and the corporate brand could be developed and this connectedness could be explained by associative and connection models and the goal priming theory. Therefore, this study investigates the influence of corporate associations on loyalty to individual brands through connections between the corporate and the consumer's self. There are three main purposes of the research. First, theories regarding corporate associations will be explored. Second, theories of self-concept will be investigated and self connectedness with corporate brands will be explored. Third, the effects of the connectedness between the self and the corporation on corporate identification and loyalty to individual brands will be investigated. For the purposes of this research, the types of corporate associations are classified into corporate ability (CA) associations and corporate social responsibility (CSR) associations. Furthermore, the connectedness between the consumer's self and the corporate image are divided into two concepts: the connectedness between the individual self-concept and the corporate identity and the connectedness between social self-concept and the corporate identity. This study suggests the hypotheses that the types of consumer self connections with the corporate image could vary according to the types of corporate associations created and further that the connectedness between the corporate association and the consumer's self-concept have positive effects on loyalty to corporate individual brands. The results of testing these hypotheses are as follows. First, corporate ability associations enhance the connectedness between the consumer's individual self and corporate brands. That is, corporate ability associations influence individual connectedness between the corporate and individual self-concept positively from the viewpoint of the consumer's personal ability and branding success. In addition, corporate social responsibility associations have a positive effect on social connectedness between the corporation and the consumer's social self-concept. Second, the connectedness between the corporate brand and the consumer's self-concept affects identification with the corporation. The consumer's personal self and social self connectedness induces corporate identification. Third, individual self connectedness has a positive effect on loyalty to corporate individual brands, while social self connectedness does not. This also means that individual self connectedness with the corporate image or brand plays a more important role in forming individual brand loyalty than social self connectedness with the corporate does. In addition, social connectedness cannot influence individual brand loyalty until it passes through identification with the corporate. Fourth, consumers who experience identification with a corporate identity also show positive responses to corporate individual brands. That is, consumers also develop loyalties toward individual brands through the corporate identification because self-pursued goals that are induced by corporate associations can be achieved by consuming the individual brands that are sold by the corporate that the consumers identify with.

• Transactions of Materials Processing
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• v.17 no.5
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• pp.364-372
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• 2008

In this study, the circumferential creep behaviors ofpilgered advanced Zirconium alloy tubes such as Zr-Nb-O and Zr-Nb-Sn-Fe were investigated in the temperature range of $400\sim500^{\circ}C$ and in the stress range of 80$\sim$150MPa. The test results indicate that the stress exponent for the steady-state creep rate of the Zr-Nb-Sn-Fe alloy decreases with the increase of stress(from 6$\sim$7 to 4), while that of the Zr-Nb-O alloy is nearly independent of stress(5$\sim$6). The activation energy of creep deformation is found to be nearly the same as the activation energy for Zr self diffusion. This indicates that the creep deformation may be controlled by dislocation climb mechanism in Zr-Nb-O. On the other hand, the transition of stress exponent(from 6-7 to 4) in Zr-Nb Sn-Fe strongly suggests the transition of the rate controlling mechanism at high stresses. The lower stress exponent at high stresses in Zr-Nb-Sn-Fe can be explained by the dynamic deformation aging effect caused by interaction of dislocations with Sn substitutional atoms.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.96-101
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• 2005

Magnesium alloys have been widely used for many structural components of automobiles and aircraft because of high specific strength and good cast ability in spite of hexagonal closed-packed crystal structure of pure magnesium. In this study, uniaxial tension tests at high temperature and creep tests are done in order to investigate the characteristics of high temperature and mechanisms for creep deformation of AZ31 Mg alloy. Yield stress and ultimate tensile stress decreased with increasing temperature, but elongation increased from results of uniaxial tension test at high temperature. The apparent activation energy Qc, the applied stress exponent n and rupture life have been determined during creep of AZ31 Mg alloy over the temperature range of 473K to 573K and stress range of 23.42 MPa to 93.59 MPa, respectively, in order to investigate the creep behavior. Constant load creep tests were carried out in the equipment including automatic temperature controller, whose data are sent to computer. At around the temperature of $473K{\sim}493K$ and under the stress level of $62.43{\sim}93.59%MPa$, and again at around the temperature of $553K{\sim}573K$ and under the stress level of $23.42{\sim}39.00MPa$, the creep behavior obeyed a simple power-law relating steady state creep rate to applied stress and the activation energy for the creep deformation was nearly equal, respectively, and a little low to that of the self diffusion of Mg alloy including aluminum. Also rupture surfaces at high temperature have had bigger dimples than those at lower temperature by SEM.