• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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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.

• 한국응용곤충학회지
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• 제29권4호
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• pp.238-243
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• 1990

핵과류를 가해하는 깍지벌레중 우점종인 뽕나무깍지벌레에 대한 용도조건이 충 발육 및 수관내분포에 미치는 영향과 월풍과의 관계를 구명하기 위하여 연구한 결과는 다용과 같다. 온도에 따른 각 stage의 성장비는 생육온도 범위의 항온에서는 크게 영향을 미치지 않았으며 각 stage의 발육영점과 유효적산온도는 난이 각각 $12.3^{\circ}C$, 46.9일도, 1령약총 $10.8^{\circ}C$, 183.8 일도, 2령약충 $9.8^{\circ}C$, 188.2일도였으며 총 약충 기간에서는 $10.3^{\circ}C$, 383.0일도이었다. 자성충의 수명은 $18^{\circ}C$, $22^{\circ}C$, $26^{\circ}C$, $30^{\circ}C$에서 각각 39.6일, 28.4일, 18.1일, 15.7일이었고 포란수 및 산란수는 각각 83.0개, 75.0개이었다. 또한 각 stage의 생육적온은 22~$26^{\circ}C$ 범위이었으며 $35^{\circ}C$에서는 부화되지 않았다. 여름철에 수관내 충의 밀도는 69.6%로 가지의 하향면에서 가장 높았으며 월동 자성충의 분포비율은 NE-SE변에서 가장 높았고 월동기간중 성충의 사충율은 36.2%이었다.

• Journal of Ecology and Environment
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• 제48권2호
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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.

• 한국태양에너지학회 논문집
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• 제26권3호
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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.

• 한국치위생학회지
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• 제9권1호
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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.

• 대한가정학회지
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• 제27권1호
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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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• 제6권1호
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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.

• 한국작물학회지
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• 제15권
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• pp.1-31
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• 1974

소맥의 조숙품종육성을 위하여는 춘파성품종의 조숙인자를 추파성품종에 도입하는 것이 중요한 과제이므로 춘추파성 소맥품종의 일장과 온도조건에 따른 출수반응 및 출수기를 지배하는 생리적 요인의 구명과 출수기의 유전에 관한 지견을 얻고저 본실험을 실시하였다. 수원 작물시험장 전작포장 및 온실에서 1970년부터 조숙품종 Yecora F70, 중숙품종 수계 169호, 육성 003 만숙품종 장광, Bezostaia, Sturdy, Blueboy 등 8개품종을 상호교배하여 1972년부터 1973년에 온실 및 초자실을 이용하여 양친과 Diallel cross F$_1$을 고온장일, 고온단일, 저온장일, 저온단일의 4처리조건 및 포장조건에서 3조합의 F$_1$, F$_2$, BC$_1$, BC$_2$ 및 양친들은 고온단일조건에서 F$_1$, F$_2$ 9조합 및 그 양친은 포장에서 각각 재배 실험하였다. 그 결과를 요약하면 다음과 같다. 1. 춘화 처리후의 주요엽수는 일장 및 온도조건에 관계없이 일정하였으나 주간의 출엽속도에만 영향을 주었으며 춘파성품종은 추파성품종보다 주간엽수가 적었다. 2. 지엽전개일수의 일장 및 온도반응은 출수속도에 의하여 결정되며 일장과 온도에 따른 출엽속도의 차이는 하위엽보다 상위엽에서 컸다. 3. 춘화처리후의 출수기에 대한 생리적 요인은 일장반응과 순수조만생이며, 출수일수의 품종간 변이는 고온단일에서 가장 크고 포장조건에서 가장 적었으며 고온장일, 저온장일, 저온단일을 비슷하였다. 4. 일장차이에 의한 출수일수의 품종간 반응은 장광, Parker가 크고, Yecora F70, 수계 169 호 등 기타 품종들은 비교적 적었으며, 장광, Parker는 단일이 의하여 출수일수가 크게 지연되는 감광성 품종이었다. 5. 일장반응은 온도의 영향을 크게 받고 출수일수의 품종간차이는 저온일 빼보다 고온일 때 현저히 나타났다. 6. 온도차이에 의한 출수일수의 품종간 반응은 비슷하였으며, 어떠한 품종이라도 고온에 의하여 출수가 촉진되고 저온에 의해서 지연되었다.7. 출수일수에 대한 유전은 일장 및 온도조건이 변하여도 조숙은 만숙에 대하여 부분우성이었으며, 우성의 정도는 단일에서 크고 장일에서 적었다. 8. 고온장일조건에서 출수일수의 품종간 차이는 수수조만성의 차이라고 할 수 있으며, 춘파성품종인 Yecora F70은 추파성품종에 대하여 우성정도가 컸고 추파성품종간에는 우성정도가 없거나 적었다. 이때의 유효 우성 유전자수는 1쌍의 대립유전자에 의해서 지배되나 다소의 미동유전자가 관여되었다. 9. 출수일수에 관여하는 비감광성은 감광성에 대하여 우성단인자차에 의하여 지배되었고 저온조건에서는 단일감응성의 발현정도가 둔화 또는 억제되었다. 10. 순수 조만성과 단일감응성은 모두 조숙이 만숙에 대하여 부분우성으로 표현되었다. 11. 출수기에 관여하는 감온성의 품종간반응은 대립유전자 및 비대립유전자의 지배를 받으며 같은 대립유전자를 가진 품종군에서는 비감온성이 감온성에 대하여 우성으로 표현되나 일장 및 순수 조만성보다는 그 정도가 미미하다. 12. 장광과 수계 169호 사이에는 감광성에 관여하는 1쌍의 대립인자 ee와 EE에 의하여 조만이 결정되었고, 장광과 Yecora F70사이에는 ee, enen과 EE, EnEn의 2쌍의 대립인자에 의하여 지배된다고 추정되었다. 이때 EE와 EnEn는 조숙방향에 상가적으로 작용하여 단일조건하에서는 EE의 효과가 EnEn의 효과보다 크다. 장일 조건하에서는 EE의 효과는 나타나지 않고 EnEn효과만 발현된다. En과 en 사이에 우열관계는 E와 e 사이보다 적고 상가적 작용을 하고 있다고 본다. 13. 본 실험의 포장조건에서는 2개정도의 우성주동유전자를 가정할 수 있으나 생육초기의 저온단일과 생육후기의 고온장일의 영향으로 2개의 우성유전자 표현이 불확실하며 F$_2$분리에 있어서는 일장 및 온도의 영향과 미동유전자의 영향으로 연속변이를 하였다. 14. 출수일수의 유전력은 0.51-0.72로서 어느 조건에서나 높은 경향으로 초기세대의 선발효과가 큰 것으로 인정되었으며, 환경에 의하여 다소의 차이가 있어 장일보다는 단일에서 유전력이 컸고, 저온보다는 고온에서 큰 경향이었다. 또한 감광성의 유전력은 0.86-0.76으로 컸으나 온도효과의 유전력은 적었다. 15. 출수기가 빨라지므로서 1수입수, 천입중, 수량이 낮아지는 상관관계를 보여 조숙다수성 품종선발이 어렵다는 결과를 보였으나 수수와는 부의 상관(유의성은 없음)을 보여 조숙품종으로서 수수형 품종을 선발하면 수량을 올릴수 있는 약간의 가능성도 보였다.

• 대한통합의학회지
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• 제9권2호
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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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• 제53권3호
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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.