• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.170-176
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• 1997

The published works on steam curing effect have been generally concentrated on the subject, "compressive strength". However a practical test for durable steam curing concrete products has not been performed in domestic. In this study, the maximum temperature of steam is considered as a major variable to investigate the freezing and thawing resistance of the steam curing concrete. All of the specimen were cured for 24 hours which included presteaming 4 hour. Finally we found that the most effective curing condition is the case of one-day and 14-day specimens after the 24 hours steam curing at $74^{\cire}C$ degree curing temperature. It is also found that the durability of one-day samples are much weaker than those of 14-day samples. Consequently, we can conclude that the samples that produced immediately after a steam curing are more possible to deteriorate from the freezing and thawing environment.vironment.

• Korean journal of applied entomology
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• v.29 no.4
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• pp.238-243
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• 1990

These studies were conduced to investigate the effects of temperatures on development of each stage and distribution within tree and overwintering of mulberry scale, Pseudaulacaspis pentagona Tar. & Tozz. Growth ratio of each stage with different temperatures was not significant within range of optimum temperatures of growth. Developmental threshold and effective temperatures of each stage were $12.3^{\circ}C$ and 46.9 degree day in eggs, $10.8^{\circ}C$, and 183.8 degree day in first nymph, $9.8^{\circ}C$ and 188.2 degree day in second nymph, $10.3^{\circ}C$ and 383.0 degree day in gross nymphal stage, respectively. Longevity of female adults were 39.6 days in $18^{\circ}C$, 28.4 days in $22^{\circ}C$, 18.1 days in$26^{\circ}C$, and 15.7 days in$30^{\circ}C$. Average number of eggs in ovary and laid by individual female were 83.3 and 75.7, respectively. Optimum temperatures of growth were $22^{\circ}C$-$26^{\circ}C$ but all the eggs were not hatched at $35^{\circ}C$. Distribution of each stage within tree in summer was great at lower part of branch and overwintering adults was dominantly located in NE-SE followed by SE-SW, SW-NW and NW-NE. Percent mortality due to cold weather was 36.2.

• Journal of Ecology and Environment
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• v.48 no.2
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• pp.173-181
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• 2024

Background: Pollination is an ecosystem service of utmost importance for agriculture. In this context, the study aimed to evaluate the pollination service of naturally occurring bees and after densification with colonies of stingless bees (Nannotrigona testceicornis and Tetragonisca angustula) in commercial strawberry plantation. The study was carried out in the four seasons of the year and under two experimental conditions: natural pollination (NP) and pollination under bee densification. The supply of flowers and bee density were estimated. For bee densification, four boxes of colonies of Iraí bees and four of Jataí bees were placed near the strawberry plantation. Five treatments were established for each condition, considering NP and pollination with bee densification on different days from flower anthesis, ranging from the 1st to the 5th day. Fruits were harvested, quantified, and submitted to evaluations to determine biometry, degree of deformity, and percentage of fertilized achenes. Results: There was a higher density in summer compared to other seasons in both conditions evaluated. The weight was greater (20.19 g) when fruits were pollinated on the first day after floral anthesis under pollination conditions with bee densification. It was observed that free pollination provided fruits with greater a greater of deformation of flowers on the fourth and fifth day after anthesis. However, when bee density became higher, the greatest degree of deformity was observed only in fifth-day fruits. The densification with stingless bees provided a 50% increase in the number of bees present on strawberry plants in summer and also a 15% increase in fruit weight and the occurrence of a lower degree of fruit deformity. Conclusions: Density with stingless bees provided a 50% increase in the number of bees present on strawberry plant in the summer, with an improvement in fruit quality and aggregate commercial value, providing a 15% increase in fruit weight and a lower degree of deformity under the conditions of densification of Iraí (N. testceicornis) and Jataí (T. angustula) bees. Under the evaluated conditions, the introduction of stingless bee boxes in the summer is recommended.

• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.119-125
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• 2006

The impacts of climate changes on building energy demand were investigated by means of the degree-days method. Future trends for the 21st century was assessed based on climate change scenarios with 7 global climate models(GCMs). We constructed hourly weather data from monthly temperatures by Trnsys 16. A procedure to estimate heating degree-days (HDD) and cooling degree-days (CDD) from monthly temperature data was developed and applied to three scenarios for Inchon. In the period 1995-2080, HDD would fall by up to 70%. A significant increase in cooling energy demand was found to occur between 1995-2004(70% based on CDD). During 1995-2080, CDD would Increase by up to 120%. Our analysis shows widely varying shifts in future energy demand depending on season. Heating costs in winter will significantly decrease whereas more expensive electrical cooling energy will be needed.

• Journal of Korean society of Dental Hygiene
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• v.9 no.1
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• pp.141-151
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• 2009

Cognitive degree of musculoskeletal symptoms and existence (or non-existence) of experience was conducted following dental hygienists' health habits, heath state and working environment targeting dental hygienists who were working for the dental clinics in Masan-si, Changwon-si and Jinhae-si in Gyeongsangnam-do for one year or more. The research findings were as follows. 1. Cognitive degree of musculoskeletal symptom following general characteristics was the highest among the subjects who were 40 years old or above. 2. As for the education level, cognitive degree of musculoskeletal symptoms was high while prevalence was low, which were statistically significant when the education level was higher. 3. Cognitive degree of musculoskeletal symptom was high when the subjects exercised, and cognitive degree of musculoskeletal symptom and prevalence were significantly high when they are engaged in leisure activities or hobbies. 4. Prevalence of musculoskeletal symptoms was statistically high if they are afflicted with disease, if they feel burdened by their job, if they suffer from considerable physical fatigue, if they feel chronic fatigue or if they feel that their health state is poor. 5. Cognitive degree of musculoskeletal symptom and prevalence were higher, which was statistically significant, when the number of years worked was higher. 6. Cognitive degree of musculoskeletal symptom was higher, but prevalence was lower when the time that they were seated was longer. This research demonstrated that the musculoskeletal disorders related to their job that afflicts the dental hygienists is not caused by one element, but it is possible to see that the musculoskeletal disorders results from the interaction of the diverse elements that are interrelated such as the subjects' characteristics and health habits and heath state, working environment and so forth including inappropriate work related movements. To this, dental hygienists need to improve their health habits so that they can form proper health habits that will ensure health in every day life on their own with the improvement of their every day life habit and positive self-evaluation to act on the health promotion behaviors, education and publicity, and measures to prevent and to manage musculoskeletal disorders in overall need to bepursued after in an active manner.

• Journal of the Korean Home Economics Association
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• v.27 no.1
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• pp.47-58
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• 1989

This study was undertaken to investigate whether the stress caused by day/night shifts on industrial workers can be affected through nutritional status. A sample of 573 female industrial workers, aged 17 through 23 years, from 4 different industries (2 in normal, 2 in 3 shift work pattern) were surveyed by questionaire examining their nutritional status, food intake, dietary habit, sleep complaint, performance of digestive organs, and degree of fatigue. Shift workers were surveyed during night work. The results are summarized as follows: 1. Sleep complaints and degree of fatigue in shift workers were higher than normal workers, whereas the performance of digestive organs were as lower than normal workers. These results showed that shift workers were more stressed than normal workers. 2. The workers who were surveyed were all poor in nutritional status. The intakes of calorie, protein, Ca, riboflavin, and ascorbic acid were lower than Korean Recommanded Dietary Allowences (RDA). Dietary habit of the shift workers was irregular. 3. There was a negative correlation between nutritional status and degrss of fatigue. The intakes of energy nutrients, ascorbic acid, and niain were significantly related to the degree of fatigue in which protein intake was found to be most influential. Among workers with the same level of protein intake, shift workers showed higher degree of fatigue. When the protein intake of shift workers was 100-125% of R.D.A., they showed the same degree of fatigue to the average normal workers.

• Journal of Community Nutrition
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• v.6 no.1
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• pp.35-41
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• 2004

Cardiovascular disease has the highest mortality rate in South Korea. Previous studies have reported that serum cholesterol level relates to intake of dietary fat and cholesterol. Therefore, in this study we developed a semiquantitative food frequency questionnaire (FFQ) for Koreans with a high-risk of hypercholesterolemia and to validate the FFQ. Semiquantitative FFQ, which includes 160 food items, reflects intakes of energy, fat, saturated fatty acid (SFA), monounsaturated fatty acid (MUPA), polyunsaturated fatty acid (PUPA) and cholesterol. We chose food items from the previous study of our research group (Suh 1999) which reported a nutritional status of Korean adults with normocholesterolemia, borderline and hypercholesterolemia. To validate the FFQ, we compared the results of the FFQ with those of a 3-day food record using a paired t-test. In addition, we calculated Pearson's and Spearmen's correlation coefficients. Intakes assessed by the FFQ and a 3-day food record were classified into quartile and the degree of agreement was obtained. Fifty-five participants responded for the validation study by completing both the FFQ and a 3-day food record. Pearson's correlation coefficients between estimated intakes by respective methods for energy, fat, SF A, MUPA, PUPA and cholesterol were 0.32,0.41,0.37,0.41,0.37 and 0.21, respectively. Spearman's correlation coefficients of energy, fat, SF A, MUPA, PUPA, cholesterol were 0.31, 0.44, 0.39, 0.46, 0.46, and 0.37, respectively. Nutrient densities in 1000kcal were compared. Pearson's correlation coefficient of cholesterol density increased and other values were similar with original values. The average degree of agreement was 67％ that intakes of energy, fat, SF A, MUPA, PUPA and cholesterol assessed by the FFQ and 3-day food records were classified within the same and the adjacent quartile. On the average, 8％ were misclassified into the extreme opposite quartile. The average of weighted kappa was 0.46. In conclusion, the FFQ developed in this study is considered to be a reliable tool to assess nutrient intakes for Koreans with a risk of hypercholesterolemia because the FFQ reflects the intakes of energy, fat, SFA, MUFA, PUPA, and cholesterol.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.1-31
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• 1974

Introducing genes for earliness of wheat varieties is important to develop early varieties in winter wheat. In oder to obtain basic informations on the response of heading to the different day length and temperature treatments and on the inheritance of heading dates, experiments were conducted at the field and greenhouse of the Crop Experiment Station, Suwon. Varieties used in this experiments were, early variety Yecora F70, medium varieties Suke #169, Parker and Yukseung #3, and late varieties Changkwang, Bezostaia, Sturdy and Blueboy. The parents and F$_1$s of partial diallel crosses of above eight varieties were subjected the following four different treatments; 1. high temperature and long day, 2. high temperature and short day, 3. low temperature and long day, and 4. low temperature and short day. The same materials were grown also in field condition. Parents, F$_1$ and F$_2$ generation were grown also in both greenhouse under high temperature and short day and in field. The results obtained were summarized as follow: 1. No effects of temperature and daylength on the number of leaves on the main stem were found when -varieties were vernalized. The number of main stem leaves were fewer for spring type of varieties than for winter type of varieties. 2. The effects of temperature and daylength on the days to flag leaf opening were dependent on the speed of leaf emergence. The speed of leaf emergence were faster for lower leaves than for upper leaves. 3. The response to short day and long day (earliness of narrow sense) of varieties were found to be direct factor responsible to physiology of heading dates in vernalized varieties. Great difference of varieties to heading date was found in high temperature and short day treatment, but less differences were found in high temperature and long day, low temperature and long day and low temperature and short day treatments respectively. The least varietal difference for heading dates was found in the field condition. 4. Changkwang and Parker were found to be the most sensitive to short day treatment (photosensitive) and the heading of these varieties were delayed by short day treatment. No great varietal differences were found among other varieties. 5. Varietal differences of heading dates due to daylength were greater in high temperature than in low temperature. 6. Varietal differences of heading dates due to temperature were not great. but in general the heading dates of varieties were faster under high temperature than under low temperature. 7. Earliness of heading dates was due to partial dominance effect of genes involved in any condition. The degree of dominance was greater under short day than under long day treatment. 8. The varietal differences of heading date under high temperature and long day were due to earliness or narrow sense (response to long day) of varieties. The degree of dominance was greater for Yecora F70, spring type than for other winter type of varieties. No differences or less differences of degree of dominance was found among winter type of varieties. The estimated number of effective factor concerned in the earliness of narrow sense was one pair of allele with minor genes. 9. The insensitivity of varieties to short day treatment in heading dates was due to single dominant gene effect. Under the low temperature the sensitivity of varieties to short day treatment was less apparent. 10. The earliness of short day and long day (earliness of narrow sense) sensitivities of varieties appearea to be due to partial dominance of earliness over lateness. In strict sense, the degree of the dominance should be distinguished. 11. Dominant gene effects were found for the thermo-sensitivity of varieties, and the effect was less, significant than the earliness in narrow sense. 12. One pair of allele, ee and EE, for photosensitivity was responsible for the difference in the heading dates between Changkwang and Suke #169. Two pairs of alleles, ee, enen and EE, EnEn. appeared to be responsible for the difference between Changkwang and Yecora F70. The effects of EE and EnEn were, additive to the earliness and the effects of EE were greater than EnEn under short day. However, the effects of EE were not evident in long day but the effects of EnEn were observed in long day. 13. Two pairs of dominant alleles for the earliness were estimated from the analysis of F$_1$ diallels in the field but the effects of these alleles in F$_2$ were not apparent due to low temperature and short day treatment in early part of growth and high temperature and long day treatment in later part of growth. The F$_2$ population shows continuous variation due to environmental effects and due to other minor gene effects. 14. The heritabilities for heading dates were ranged from 0.51 to 0.72, indicating that the selection in early generation might be effective. The extent of heritability for heading dates varied with environments; higher magnitude of heritability was obtained in short day treatment and high temperature compared with long day and low temperature treatments. The heritabilities of heading date due to response to short day were 0.86 in high temperature and 0.76 in low temperature. The heritabilities of heading date due to temperature were not significantly high. 15. The correlation coefficients of heading dates to the number of grains per spike, weight of 1, 000 grains. and grain yield were positive and high, indicating the difficulties of selections of high yielding lines from early population. But no significant correlation coefficient was obtained between the earliness and the number of spikes, indicating the effective selection for high tillering from early varieties for high yielding.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.2
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• pp.183-192
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• 2021

Purpose : To investigate the degree of smartphone addiction among health-related college students, and to compare and analyze the effect of the degree of addiction on attention control and interpersonal support. Methods : 184 people who voluntarily participated and agreed to fill out the questionnaire were randomly sampled. The smartphone self-diagnosis scale was used to measure the degree of smartphone addiction, and the Attentional Control Questionnaire (ACQ) was used as a tool to measure the degree of attention control. In addition, the Interpersonal Support Evaluation List (ISEL) was used to measure the degree of interpersonal support. Results : In comparison of the degree of smartphone addiction according to the general characteristics of the subjects, there was no significant difference according to religion, major, and grade, but there was a significant difference in gender and daily use time of smartphones (p <.05). There was a significant difference in the degree of attention control according to the level of smartphone addiction (high risk, potential risk, general user group) (p <.05), but there was no significant difference in the degree of interpersonal support. Conclusion : The degree of smartphone addiction was relatively higher for women than for men, and users who used it for a long time per day were more addicted. It also showed that attention control was further reduced in highly addictive users.

• Journal of Animal Science and Technology
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• v.53 no.3
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• pp.223-226
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• 2011

The current study was undertaken to determine the effect of retinoic acid (RA) on proliferation and differentiation of preadipocytes from male and female pigs. The preadipocytes were isolated from new-born male and female pigs by collagenase digestion and washed three times one day after seeding (designated as day 0 of culture). RA was included in the media at various concentratives from day 0 to 2. The cell number was measured on day 2 with hematocytometer after trypsin digestion. Cell differentiation was determined on day 6 by measuring glycerol-3-phosphate dehydrogenase activity. RA (0.1, 1 and 10 uM) showed no effect on proliferation of preadipocytes from both male and female pigs. However, RA significantly decreased differentiation of pig preadipocytes. Degree of differentiation with 0.1 uM, 1 uM and 10 uM of RA treatment was 80%, 41% and 29% respectively, compared with control. Similar inhibitory effect was found in the female pigs; 77%, 28% and 16% respectively. It is interesting that RA treated on cell proliferation stage had no effect on proliferation but had a strong inhibitory effect on differentiation which is happening in the late stage of cell culture.