• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.12
• /
• pp.1619-1625
• /
• 2012

An electrical steel strip is commonly used as a core material in all types of electric transformers and motors. It is produced by a cold rolling process. In this paper, a damage-mechanics-based approach that predicts the edge fracture of an electrical steel strip during cold rolling is presented. We adopted the normal tensile stress criterion and the fracture energy method as a damage initiation criterion and a damage evolution scheme, respectively. We employed finite element analysis (FEA) to simulate crack initiation and propagation at the initial notch located at the edges of the strip. The material constants required in FEA were experimentally obtained by tensile tests using a standard and a notched sheet-type specimen. The results reveal that the edge crack was initiated at the entrance of the roll bite and that it rapidly evolved at the exit. The evolution length of the edge crack increased as the length of the initial notch as well as the front tension reel force of the strip increased.

• Journal of Korean Society of Forest Science
• /
• v.48 no.1
• /
• pp.25-28
• /
• 1980

This study examined the cold hardiness of eight cultivars of common persimmon and six cultivars of sweet persimmon growing at the southern part of Korea, to know the most susceptible tissue part, timing of damage, and the difference in freezing resistance between the cultivars during the winter of '77-'78. The cold hardiness of winter bud, cambium and xylem parenchyma of the current year twig was measured on three collection dates; 10 / 26 / 77, 1 / 26 / 78 and 3 / 26 / 78. The results were obtained as follows, 1. The least cold hardy tissue part was winter bud during mid winter and early spring. 2. On the basis of the cold hardiness of the winter bud sweet persimmon cultivars appeared to be less cold hardy than common persimmon cultivars. In the cold hardiness of cambium and xylem parenchyma, there was no consistance differece between the two group of cultivars. 3. The late frost during early spring appeared to cause the most critical damage to the winter bud of persimmon.

• Clinical and Experimental Pediatrics
• /
• v.56 no.10
• /
• pp.446-450
• /
• 2013

Purpose: This study evaluated the extent of damage due to hypothermia in the mature and immature brain. Methods: Hippocampal tissue cultures at 7 and 14 days in vitro (DIV) were used to represent the immature and mature brain, respectively. The cultures were exposed at $25^{\circ}C$ for 0, 10, 30, and 60 minutes (n=30 in each subgroup). Propidium iodide fluorescent images were captured 24 and 48 hours after hypothermic injury. Damaged areas of the cornu ammonis 1 (CA1), CA3, and dentate gyrus (DG) were measured using image analysis. Results: At 7 DIV, the tissues exposed to cold injury for 60 minutes showed increased damage in CA1 (P<0.001) and CA3 (P=0.005) compared to the control group at 48 hours. Increased damage to DG was observed at 24 (P=0.008) and 48 hours (P=0.011). The 14 DIV tissues did not demonstrate any significant differences compared with the control group, except for the tissues exposed for 30 minutes in which DG showed less damage at 48 hours than the control group (P=0.048). In tissues at 7 DIV, CA1 (P=0.040) and DG (P=0.013) showed differences in the duration of cold exposure. Conclusion: The immature brain is more vulnerable to hypothermic injury than the mature brain.

• Korean Journal of Exercise Nutrition
• /
• v.23 no.1
• /
• pp.48-54
• /
• 2019

[Purpose] The combined effect of different types of post-exercise treatment has not been fully explored. We investigated the effect of combined cold water immersion (CWI) and compression garment (CG) use after maximal eccentric exercise on maximal muscle strength, indirect muscle damage markers in the blood, muscle thickness, and muscle soreness score 24 h after exercise. [Methods] Ten men performed two trials (CWI + CG and CON) in random order. In the CWI + CG trial, the subjects performed 15 min of CWI (15℃), followed by wearing of a lower-body CG for 24 h after exercise. In the CON trial, there was no post-exercise treatment. The exercise consisted of 6 × 10 maximal isokinetic (60°·s^-1) eccentric knee extensions using one lower limb. The maximal voluntary contraction (MVC) and maximal isokinetic (60°·s^-1) strength during knee extension, as well as the indirect muscle damage markers, were evaluated before exercise and 24 h after exercise. [Results] The maximal muscle strength decreased in both trials (p < 0.001), with no difference between them. The exercise-induced elevation in the myoglobin concentration tended to be lower in the CWI + CG trial than in the CON trial (p = 0.060). The difference in the MVC, maximal isokinetic strength, muscle thickness, and muscle soreness score between the trials was not significant. [Conclusion] CWI followed by wearing of a CG after maximal eccentric exercise tended to attenuate the exercise-induced elevation of indirect muscle damage markers in the blood.

• Herbal Formula Science
• /
• v.26 no.4
• /
• pp.363-380
• /
• 2018

Objectives : We analyzed the principle of compatibility of socheongnyong-tang and expanded the range of application in clinical practice. Methods : Socheongnyong-tang was analyzed by the compatibility principle through the system of chief, deputy, assistant, and envoy, but the basic formulas of "Discussion of Cold Damage" and "Synopsis of the Golden Chamber" was used. Results : Socheongnyong-tang treats exterior wind-cold and interior water accumulation. Exterior wind-cold is treated mainly by exterior-releasing herbs constituting mahwang-tang and gyeji-tang in "Discussion of Cold Damage", and interior water accumulation is treated mainly by retained fluid-resolving herbs constituting yeonggamomigangsinha-tang, yeonggamomigagangsinbanhahaengin-tang and yeonggamomigagangsinbanhaengdaehwang-tang in "Synopsis of the Golden Chamber". Depending on the weight of exterior wind-cold and interior water accumulation, the disease condition is classified as a case where exterior wind-cold is heavier than interior water accumulation, a case where exterior wind-cold is lighter than interior water accumulation, and a case where it is equivalent. When exterior wind-cold is heavier than interior water accumulation, chief herbs are Ephedrae Herba and Cinnamomi Ramulus of exterior-releasing herbs series and deputy herbs are Zingiberis Rhizoma and Asari Radix et Rhizoma of retained fluid-resolving herbs series. When exterior wind-cold is equal to the disease condition of interior water accumulation, chief herbs are Ephedrae Herba of exterior-releasing herbs series and Zingiberis Rhizoma of retained fluid-resolving herbs series, and deputy herbs are Cinnamomi Ramulus of the exterior-releasing herbs series and Asari Radix et Rhizoma of retained fluid-resolving herbs series. When exterior wind-cold is lighter than interior water accumulation, chief herbs are Zingiberis Rhizoma and Asari Radix et Rhizoma of retained fluid-resolving herbs series and deputy herbs are Ephedrae Herba and Cinnamomi Ramulus of exterior-releasing herbs series. In any case, assistant herbs are Pinelliae Rhizoma, Paeoniae Radix alba, and Schisandrae Fructus, and envoy herb is Glycyrrhizae Radix preparata. Conclusions : In conclusion, socheongnyong-tang must differently formulate the system of chief, deputy, assistant, and envoy according to the grade of exterior wind-cold and interior water accumulation. These results suggest that socheongnyong-tang can be applied flexibly when applied in clinical practice to enhance the therapeutic effect.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.04a
• /
• pp.199-204
• /
• 2000

When fresh concrete is exposed to low temperature, the concrete may suffer from the frost damage at early ages and the strength development may be delayed. To solve such problems of cold weather concreting, admixtures called agent for enduring cold climate are developed to prevent the fresh concrete from being frozen at early ages In this study, the experiments are carried out on several kinds of agent for enduring cold climate to present their performance. According to experimental results, most kinds of agent for enduring cold climate show the satisfactory properties of decreasing the freezing point and acceleating the cement hydration in low temperature environment, which is available for placing concrete in spite of cold weather.

• 한국생물공학회:학술대회논문집
• /
• 2003.04a
• /
• pp.293-297
• /
• 2003

Glutathione and ascorbic acid have been shown to fulfill many essential functions in animal and plant growth, development, defence and protection against oxidative damage. Effects of glutathione and ascorbic acid were examined in transgenic N. tabacum cells producing hGM-CSF to determine the effects of the vitamins on growth and cell viability. In lag phase, cell viability was preserved by glutathione and ascorbic acid. Therefore, recombinant protein productivity was increased. The purpose of present study is to investigate the role of antioxidants in cold stress-induced apoptosis in plant suspension cells. Cold stress lowered cell viability and increased total genomic DNA fragmentation. Supplementing the cell cultures with glutathione and ascorbic acid inhibited cold stress-induced decrease in cell viability and increase in total genomic DNA fragmentation.

• Journal of Ecology and Environment
• /
• v.31 no.4
• /
• pp.317-325
• /
• 2008

P. glehnii, an evergreen conifer found in northern areas, is known as a cold-resistant species. In this experiment, we measured the water content, PSⅡ efficiency, chlorophyll fluorescence, pigments of the xanthophyll-cycle and activity of enzymes of the ascorbate-glutathione cycle during cold acclimation and at subsequent low-temperature conditions to examine the importance of acclimation to cold tolerance. P. glehnii showed a decrease in PSⅡ efficiency (especially in Fv) during cold acclimation and at subsequent low temperatures. However, cold-acclimated needles showed higher PSⅡ efficiency at low temperatures than nonacclimated needles. In addition, 0-YON (first-year needles) showed an increase in $\beta$-carotene and lutein, while 1-YON (one-year-old needles) immediately developed an antioxidant mechanism in the ascorbate-gluthathione cycle as soon as they were exposed to low temperature and both 0-YON and 1-YON showed increased zeaxanthin and de-epoxidation ratios at continuous low temperature. Based on our results, we suggest that P. glehnii maintain PSⅡ efficiency at low temperature by effectively protecting the photosynthetic apparatus from photo-damage by rapid induction of an antioxidant mechanism in 1-YON and dissipation of excess energy by $\beta$-carotene and lutein in 0-YON.

• Archives of Pharmacal Research
• /
• v.14 no.1
• /
• pp.93-95
• /
• 1991

Alcoholic extract of the leaves of Andrographis paniculata Ness (=AAP) was obtained by cold maceration. A dose of 300 mg/kg $(1/6of\;LD_{50})$ of the extract was selected to study hepatoprotective action against carbon tetrachloride-induced liver damage. The extract was found to be effective in preventing liver damage which was evident by morphological, biochemical and functional parameters.

• Archives of Pharmacal Research
• /
• v.14 no.1
• /
• pp.96-98
• /
• 1991

Alcoholic extract of the seeds of Vitex negundo Linn. was obtained by cold maceration. A dose of 250 mg/kg $(1/6\;of\;LD_{50})$ of the extract was selected to study the hepatoprotective action against carbon tetrachloride-induced liver damage. The extract was found to be effective in preventing liver damage which was evident by morphological, biochemical and functional parameters.