• Korean Journal of Materials Research
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• v.28 no.12
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• pp.738-747
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• 2018

For the aerospace structural application of high-strength 2xxx series aluminum alloys, stress corrosion cracking(SCC) behavior in aggressive environments needs to be well understood. In this study, the SCC sensitivities of 2024-T62, 2124-T851 and 2050-T84 alloys in a 3.5 % NaCl solution are measured using a constant load testing method without polarization and a slow strain rate test(SSRT) method at a strain rate of 10-6 /sec under a cathodic applied potential. When the specimens are exposed to a 3.5 % NaCl solution under a constant load for 10 days, the decrease in tensile ductility is negligible for 2124-T851 and 2050-T84 specimens, proving that T8 heat treatment is beneficial in improving the SCC resistance of 2xxx series aluminum alloys. The specimens are also susceptible to SCC in a hydrogen-generating environment at a slow strain rate of $10^{-6}/sec$ in a 3.5 % NaCl solution under a cathodic applied potential. Regardless of the test method, low impurity 2124-T851 and high Cu/Mg ratio 2050-T84 alloys are found to have relatively lower SCC sensitivity than 2024-T62. The SCC behavior of 2xxx series aluminum alloys in the 3.5 % NaCl solution is discussed based on fractographic and micrographic observations.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.149-158
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• 2022

This study was conducted to understand the effects of openness, positive acceptance, physical symptoms, reaction, and emotional sensitivity among adolescents' attitudes toward menstruation, and academic stress on premenstrual syndrome and dysmenorrhea. A questionnaire of 126 high school girls who agreed to participate in the study was analyzed. As a result, the subject's premenstrual syndrome score was 22.48 points and dysmenorrhea was 4.66 points, and it was found that the higher the amount of menstruation, the higher the score of premenstrual syndrome and dysmenorrhea. Factors affecting premenstrual syndrome were openness, physical symptoms, reaction, and emotional sensitivity, and the explanatory power of these variables was 49.9%. In addition, positive acceptance and physical symptoms had a significant effect on dysmenorrhea in adolescents, and explanatory power was 66.3%.

• Geomechanics and Engineering
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• v.29 no.4
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• pp.377-390
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• 2022

The stability of the roof rock-coal pillar-floor rock composite structure is of great significance to coal mine safety production. The cracks existing in the composite structure seriously affect the stability of the roof rock-coal pillar-floor rock composite structure. The numerical simulation tests of rock-coal-rock composite structures with different crack characteristics were carried out to reveal the composite structures' mechanical properties and failure mechanisms. The test results show that the rock-coal-rock composite structure's peak stress and elastic modulus are directly proportional to the crack angle and inversely proportional to the crack length. The smaller the crack angle, the more branch cracks produced near the main control crack in the rock-coal-rock composite structure, and the larger the angle between the main control crack and the crack. The smaller the crack length, the larger the width of the crack zone. The impact energy index of the rock-coal-rock composite structure decreases first and then increases with the increase of crack length and increases with the increase of crack angle. The functional relationships between the different crack characteristics, peak stress, and impact energy index are determined based on the sensitivity analysis. The determination of the functional relationship can fully grasp the influence of the crack angle and the crack length on the peak stress and impact energy index of the coal-rock composite structure. The research results can provide a theoretical basis and guidance for preventing the instability and failure of the coal pillar-roof composite structure.

• Computers and Concrete
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• v.32 no.1
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• pp.99-117
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• 2023

The crack under the influence of the higher intensities of the stresses grows and the structure gets collapsed with the time when the crack length reaches to critical value. Therefore, the fracture behavior of a structure in terms of stress intensity factors (SIF) becomes important to determine the remaining fracture strength and capacity of material and structure for avoiding catastrophic failure, increasing safety and further improvement in the design. The robustness of the method has been demonstrated by comparing the numerical results with analytical and experimental results of some problems. XFEM is used to model cracks and holes in structures and predict their strength and reliability under service conditions. Further, XFEM is extended with a stochastic method for predicting the sensitivity in terms of output COVs and fracture strength in terms of mean values of stress intensity factors (SIFs) of a structure with discontinuities (cracks and holes) under tensile loading condition with input individual and combined randomness in different system parameters. In stochastic technique, the second order perturbation technique (SOPT) has been used for the predicting the fracture behavior of the structures. The stochastic/perturbation technique is also known as Taylor series expansion method and it provides the reliable results if the input randomness is less than twenty percentage. From the present numerical analysis it is observed that, the crack tip near to the hole is under the influence of the stress concentration and the variational effect of the input random parameters on the crack tip in terms of the SIFs are lesser so the COVs are the less sensitive. The COVs of mixed mode SIFs are the most sensitive for the crack angles (α=45° to 90°) for all the values of c₁ and d₁. The plate with the shorter distance between hole and crack is the most sensitive with all the crack angles but the crack tip which is much nearer to the hole has the highest sensitivity.

• Analytical Science and Technology
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• v.37 no.5
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• pp.280-294
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• 2024

This study introduces a novel analytical method for the assessment of pralsetinib impurities and degradation products (DPs), addressing critical gaps in existing methodologies. This research aims to develop a robust HPLC method for impurity analysis, characterize degradation products using LC-MS, and evaluate the environmental impact of the method. The study began by optimizing HPLC conditions with various columns and buffers, ultimately achieving successful separation using an XBridge^® RP-C18 column with ethanol as solvent A and 50 mM formic acid at pH 2.9. This setup provided excellent peak resolution and symmetry, essential for reliable stability studies. The developed HPLC method was then adapted for HPLC-MS/MS, enhancing sensitivity and detection efficiency of DPs. Stress degradation studies of pralsetinib under different conditions (acidic, basic, oxidative, thermal, and photolytic) revealed significant degradation under acidic (29.3 %) and basic (21.5 %) conditions, with several DPs identified. Oxidative stress resulted in 19.8 % degradation, while thermal and photolytic conditions caused minimal degradation. HPLC-MS/MS analysis identified structures of five degradation products, providing detailed insights into pralsetinib's stability and degradation pathways. Method validation followed ICH guidelines Q2(R1), confirming method's specificity, selectivity, sensitivity, linearity, accuracy, precision, and robustness. The method exhibited strong linearity with a coefficient of determination (r²) greater than 0.999 for pralsetinib and its impurities. This method advances impurity detection and DPs characterization, ensuring the quality and safety of pralsetinib. Additionally, method's environmental impact was assessed, aligning with sustainable analytical practices. These findings provide essential data on pralsetinib's stability, guiding storage conditions and ensuring its efficacy and safety in pharmaceutical applications.

• Journal of Ocean Engineering and Technology
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• v.29 no.1
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• pp.16-27
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• 2015

The design challenges when attempting to obtain sufficient strength for a deepwater steel catenary riser (SCR) include high stress near the hang-off location, an elevated beam-column buckling load due to the effective compression in the touchdown zone (TDZ), and increased stress and low-cycle fatigue damage in the TDZ. Therefore, a systematic strength analysis is required for the proper design of an SCR. However, deepwater SCR analysis is a new research area. Thus, the objective of this study was to develop an overall analysis procedure for a deepwater SCR. The structural behavior of a deepwater SCR under various environmental loading conditions was investigated, and a sensitivity analysis was conducted with respect to various parameters such as the SCR weight, weight of the internal contents, hang-off angle (HOA), and vertical soil stiffness. Based on a deepwater SCR design example, it was found that the maximum stress of an SCR occurred at a hang-off location under parallel loading direction with respect to the riser plane, except for a wave dominant dynamic survival loading condition. Furthermore, the tensile stress governed the total stress of the SCRs, whereas the bending stress governed the total stress at the TDZ. The weight of the SCR and internal contents affected the maximum stress of the SCR more than the HOA and vertical soil stiffness, because the weight of the SCR, including the internal contents, was directly related to its tensile stress.

• Journal of Convergence for Information Technology
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• v.11 no.7
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• pp.195-201
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• 2021

This study analyzed the correlation between sensory processing types and stress responses in university students. A survey was conducted on 99 university students in Gyeonggi-do and Chungcheong-do. The survey contents consisted of Adolescent/Adult Sensory Profile and Stress Response Inventory. Data were analyzed using SPSS version 21.0 for descriptive statistics and Pearson correlation. As a result of the study, low-registration and sensory sensitivity were all correlated except for aggression of stress response, and sensory avoiding was all correlated of stress response. Sensory seeking was net related to any domain of stress response. Based on the results of this study, taking into account the correlation between sensory processing types and stress responses, it is recommended for convergence with other treatments to develop self-regulation strategies for coping with stress in university students.

• Anxiety and mood
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• v.7 no.2
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• pp.107-112
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• 2011

Objective : This study aimed to ascertain the effect of interpersonal sensitivity/resilience on depression and anxiety in firefighters whose frequency of exposure to traumatic events is high. Method : A survey was performed and data related to 75 firefighters were analyzed. Questionnaires included the Beck Depression Inventory (BDI) and Impact of Event Scale-Revised (IES-R). To assess the susceptibility or protector roles with respect to psychopathology, the Interpersonal Sensitivity Measure (IPSM) and Conner-Davidson Resilience Scale (CD-RISC) were used. Results : The personality characteristic, interpersonal sensitivity (IPSM) showed a significant positive correlation with depression (BDI, r=0.557, p<0.001) and posttraumatic stress symptoms (IES-R, r=0.316 ; p<0.001). In contrast, resilience and symptom parameters (BDI, IES-R) were negatively correlated with each other, but not statistically significant. However, an adaptive factor for change, a third sub-factor of CD-RISC, had significant negative correlation with depression and anxiety symptoms (BDI, r=-0.275, p<0.005 ; IES-R, r=-0.254, p<0.005). Conclusion : The results of the present study showed that some personality traits may act as vulnerability or protective factors with respect to the psychopathologies of depression and anxiety.

• The Plant Pathology Journal
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• v.16 no.3
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• pp.130-136
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• 2000

Differences in physiological and biochemical responses between sensitive and tolerant rice cultivars to ozone were investigated to develop reliable indications of early ozone damage. Three Korean local rice cultivars -sen-sitive cultivar Dongjin (DJ), moderately tolerant cultivar Hwayeong (HY) and tolerant cultivar Ilmee (IM) were exposed to ozone at the concentrations of 100 nl $\textrm{l}^{-1}$ or 200 nl $\textrm{l}^{-1}$ , 8 h per day for 10 days in a controlled-environment fumigation chamber. The rice cultivars seemed to be endurable to ozone stress at the concentration of 100 nl $\textrm{l}^{-1}$ which is frequently monitored during the growing season in summer. However, severe damage was induced and differential sensitivity was clearly noted among the rice cultivars at the higher ozone concentration. Activation of the glutathion (GR) -ascorbate peroxidase (APX) cycle was likely to be responsible for protection of rice plants against ozone exposure, relating difference in sensitivity of rice cultivars to ozone. Photosynthetic activity appeared to be one of sensitive responses, for which chlorophyll fluorescence and leaf greenness can together provide a very reliable index, a degree of photosynthetic damages by ozone. Formation of malondialdehyde (MDA) was also considered as an indication that can differentiate cultivars sensitivity to ozone. However, the changes in polyamines and total phenolics were not consistent with exposed ozone concentrations and/or ozone sensitivity of the cultivars. The behavior of polyamines and phenolics in the damaged plants at high ozone levels could be interpreted as an indication of ozone injury rather than activation of additional protection mechanisms scavenging active oxygen species formed by ozone. Several responses triggered by ozone could explain the differential sensitivity of the rice cultivars and be used as reliable indications of relative ozone damage to rice plant.

• Journal of Community Nutrition
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• v.8 no.2
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• pp.107-113
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• 2006

Sensory factors are important determinants of appetite and food choices but little is known about factors affecting taste acuity and preference of Koreans. Any factors causing deficits in sweet taste perception may lead to over consumption of simple sugar, which is related to several chronic diseases. This study was conducted to determine factors affecting sweet taste sensitivity and preference. Subjects were 30 government employees who were serving as school dietitians or in the area of public health while they were studying in the program for the qualification to become nutrition teachers. Sweet taste threshold and the optimally-preferred sweetness of omija jelly were determined by a sensory evaluation and general characteristics, health-related lifestyles, dietary habits and food preferences were determined using a self-administered questionnaire. For the subjects of this study, detection threshold concentration of sucrose solution was $0.184{\pm}0.06%$ and optimally-preferred sucrose concentration of omija jelly was $13.88{\pm}2.28%$ and there was no significant correlation between the sweet taste sensitivity and preference. Subjects who had higher(${\ge}4$ out of 10) physical or psychological stress and who had late getting-up time (after 7am) tended to have lower sweet taste threshold (higher sensitivity) than their counterpart. The sweet taste preference determined by optimally-preferred sucrose concentration of omija jelly tended to be lower in the subjects who eat slowly. Those who answered in the questionnaire to prefer sweet foods did have significantly higher optimally-preferred sucrose concentration of omija jelly. Further research is required to determine whether decreased sensitivity and increased preference for sweetness can increase the actual intake of simple sugar. (J Community Nutrition 8(2): 107 -113, 2006)