• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.3
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• pp.162-167
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• 2021

Aluminum (Al) stress in acidic pH is known to decrease the growth and productivity of alfalfa. However, not much is known about how the application of silicon (Si) affects the Al stress response in alfalfa. This study was conducted to evaluate the effect of exogenous application of Si on the growth of alfalfa seedlings exposed to Al stress in pots. Alfalfa seedlings grown in pots for 2 weeks were treated either Al stress (pH 4.0, 0.2 mM Al) or Al stress + Si (1 mM) for 5 days, lengths and biomass of shoot and root, and chlorophyll and carotenoid contents in leaf tissues were analyzed respectively. Al stress treatment inhibited shoot and root growth, and decreased fresh and dry weights, and chlorophyll content in leaves, but increased carotenoid content. In contrast, when alfalfa seedlings treated with Al stress combined with Si, delayed growth caused by Al stress of shoot and root of alfalfa seedlings was restored, dry weight was increased and chlorophyll content of leaf tissue was increased, but carotenoid content was decreased. These results suggest that Si has a function of alleviating Al toxicity in alfalfa, of which it exhibits a mitigating effect by a function that overlaps with some of the intracellular functions of carotenoids.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.39
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• pp.177-192
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• 1996

The organization of business included many a factors that gave rise to the stress. The modem peoples in this organization lived in the flood of the stress. Job stress was an important factors which injured of the employee health, the employee health injured reduce the organizational function. The factors such as personal differences, stressors, personality, cognitive traits etc. should be considered in the study of job stress. The cognitive appraisal is an important factor in the study of job stress and a process of coping strategy. Job stress can be controlled and coped by organizational and personal ability. The coping strategy of job stress is also determined by the personal differences rather than by the intensity of stress symptoms. In copying the stress, to be considered the factors such as interpersonal correlation, organizational climate, career development, job redesign, selection and placement, training. However, these factors should be managed in the scientific, objective, reasonable manner effectively.

• Journal of Korea Entertainment Industry Association
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• v.15 no.1
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• pp.229-236
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• 2021

The purpose of this study is to investigate how the combined intervention of occupation-based intervention and computerized cognitive rehabilitation treatment affects the psychosocial function, cognitive function, and depression of stroke patients. 23 stroke patients were divided into experimental group(n=11) and a control group(n=12), and the experimental group and the control group received CoTras for 4 weeks and 30 minutes each, and additionally the experimental group received task-based intervention for 30 minutes before the start of CoTras. It was conducted 20 times for a total of 4 weeks. Self-efficacy scale, stress scale, depression scale, neurobehavioral cognitive status examination were used. As a result of the study, the experimental group showed significant improvement in improvement of self-efficacy, stress, and depression than the control group, and the experimental group showed a small effect difference in magnitude of effect from the control group in cognitive function. Based on this study, it is possible to utilize the simultaneous task-based intervention with CoTras to improve psychosocial function, depression and cognitive function in stroke patients.

• Journal of the Korea Concrete Institute
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• v.15 no.5
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• pp.662-669
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• 2003

Recently, the serviceability and durability of concrete structures under thermal load have received great attention. The thermal stress and clacking behavior of concrete at early ages are one of the important factors that affect such serviceability and durability of concrete structures. Nevertheless, most studies on the behavior of early-age concrete have been confined to the temperature and strain development itself in the laboratory. The desirable efforts to explore the material properties of concrete at early-ages have not been made extensively so far. The purpose of the present study is, therefore, to identify some important material properties that affect the stress behavior of concrete at early-ages. To this end, full-scale concrete base-restrained wall members have been fabricated, and many sensors including thermocouples, strain meters and stress meters were installed inside of the wall members. These sensors were to measure the development of temperatures, strains and stresses at several location in concrete walls during the hardening and curing phase of early-age concrete. By using these measured values of strain and stress, the compliance function at early-age was identified. The basic form of compliance function derived in this study follows the double-power law. However, the results of present study indicate that the values of existing compliance functions are much lower than actual values, especially at very early-ages. It can be seen that the prediction of stresses of early-age concrete based on the proposed compliance function agrees very well with test data. The present study allows more realistic evaluation of varying stresses in early-age concrete under thermal load.

• Journal of Industrial Convergence
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• v.21 no.2
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• pp.85-92
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• 2023

Abnormal spinal disease and function, in addition to simple musculoskeletal problems, can disrupt homeostasis and cause direct and indirect physiological side effects. Part or all of the immune function can be compromised, exposing you to more disease, especially if the nerves running through your spine do not deliver the proper signals to the organs that regulate your immune system. This study focuses on basic anatomic and physiological knowledge and seeks to consider potential mechanisms by which spinal function may potentially help maintain or improve immune function. To this end, we examine the roles of the spine in relation to hematopoiesis, stress, respiration, spine-nerve relationships, and the immune system, and confirm that these roles may influence immune function.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2410-2415
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• 2011

The needs for enlargement of width of existing embankment have been increasing due to heavy traffic and large amount of transporting goods. In this study, it was intended to derive formula for estimating vertical stress induced by additional embankment. Theoretical background for handling plain strain problem was investigated. It can be seen that stress function considered in the analysis was justifiable for compatibility and boundary condition. Notes for using derived formula were also considered.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.1
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• pp.50-56
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• 2007

Exhaust manifold is generally subjected to thermal cycle loadings ; at hot condition, large compressive plastic deformations are generated, and at cold condition, tensile stresses are remained in highly deformed critical zones. These phenomena originate from the fact that thermal expansions of the runners are restricted by inlet flange clamped to the cylinder head, because the former is less stiff than the latter and, the temperature of the inlet flange is lower than that of the runners. Since the failure of an exhaust manifold is mainly caused by geometric constraints between the cylinder head and the manifold, the thermal stress can be controlled by geometric factors. The generic geometric factors include the inter distance (2R), the distance from the head to the outlet (L), the tube diameter(d) and the tube thickness (t). This criteria based on elastic analysis up to onset of yield apparently indicate that the pre-stress also reduces the factor; however, high temperature relaxation may reduce this effect at later operation stage.

• Plant Biotechnology Reports
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• v.5 no.1
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• pp.61-69
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• 2011

The dehydration-responsive element binding proteins (DREB1)/C-repeat (CRT) binding factors (CBF) function as transcription factors and play an important role in agricultural biotechnology and molecular biology studies of drought and freezing stress tolerance. We generated transgenic Lolium perenne plants containing the PCR-cloned Arabidopsis DREB1A/CBF3 gene (AtDREB1A/CBF3) to study the function of this gene construct in drought and freezing tolerance in a species of turfgrass. Compared to the control, AtDREB1A/CBF3 transgenic L. perenne plants showed enhanced drought and freezing stress tolerance. The activities of the enzymes superoxide dismutase (SOD) and peroxidase (POD) were higher in transgenic plants than in the non-transgenic plant control. These results demonstrate that the expression of the AtDREB1A/CBF3 gene in transgenic L. perenne plants enhanced drought and freezing tolerance and that the increased stress tolerance was associated with the increased activities of antioxidant enzymes. These results are relevant to stress biology and biotechnology studies of turfgrass.

• Development and Reproduction
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• v.22 no.2
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• pp.165-174
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• 2018

The aim of study is to contribute to this knowledge-base by investigating the respiratory function, the metabolic rate and the difference of physiological responses un-der low water temperature ($20^{\circ}C{\rightarrow}15^{\circ}C$) stress be-tween diploid and triploid far eastern catfish, Silurus asotus. During the 48 hrs of water temperature stress exposure time, the respiratory frequencies, $CO_2$ and ${NH_4}^+$ concentrations of diploid had higher values than those of triploid (p<0.05). However, pH of triploid was higher than those of diploid (p<0.05), and oxygen consumption rate was not different between diploid and triploid (p>0.05). The level of plasma cortisol and plasma glucose of triploid was lower than those of the diploid (p<0.05). However, in case of lactic acid, there were not significant between triploid and diploid (p>0.05). These results suggest that diploid was more sensitive for low water temperature stress response than triploid in this species.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.5
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• pp.51-64
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• 1991

In this paper, an attempt is made to analyze the impulsive stress directly underneath the concentrated impact point for a supported square plate by using the three-dimensional dynamic theory of elasticity and the potential theory of displacement (stress function) on the supposition that the load, F$_{*}$0 sin .omega.t, acted on the central part of it. The results obtained from this study are as follows: 1. The impulsive stress cannot be analyzed directly underneath the acting point of concenrated impact load in privious theories, but can be analyzed by using the three-dimensional dynamic theory of elasticity and the potential theory of displacement. 2. Theorically, with increasing the pulse width of applied load, it was possible to clarify that the amount of stress in the point of concentrated impact load was increased and that of stress per unit impulse was decreased. 3. The numerical inversion of laplace transformation by the use of the F.F.T algorithm contributes the reduction of C.P.U time and the improvement of the accuracy or results. 4. In this paper recommended, it is found that the approximate equation of impact load function P (.tau.) = A.tau. exp (-B.tau.), and P (.tau.) =0.85A exp (-B.tau.) sinC.tau. could actually apply to all impact problem. In compared with the experimental results, the propriety of the analytical method is reasonable.