• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.16-24
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• 2019

The corrosion amounts of steel structures can be different depending on their installation condition and height. Thus, their corrosion maintenance should be considered depending on installation conditions of local structural members. In this study, an atmospheric exposure test was conducted to evaluate the corrosion amount and the corrosion rate depending on the installation condition and height of a steel water gate using monitoring steel plates and corrosion environment measuring sensors. The mean corrosion depth was evaluated using the weight loss method and the galvanic corrosion current was measured by corrosion environment measuring sensors. Local corrosion rate of local structural member in steel water gate was estimated using measured mean corrosion depths and galvanic corrosion currents. From this measurement results, the corrosion damage in horizontal member of the cross beam was highly evaluated than those of other structural member as skin plate, etc. The relative difference in the corrosion rate of a local structural member could be highly affected by local corrosion environments of steel water gate members. Therefore, an appropriate maintenance method should be considered for local corrosion damages of local structural members determined by local corrosion environments of a steel water gate.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.849-856
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• 2017

Objective: The net energy requirement for the maintenance ($NE_m$) of broilers was determined using regression models by the indirect calorimetry method (ICM) or the comparative slaughter method (CSM). Methods: A $2{\times}4$ factorial arrangement of treatments including the evaluation method (ICM or CSM) and feed intake (25%, 50%, 75%, or 100% of ad libitum recommended) was employed in this experiment. In the ICM, 96 male Arbor Acres (AA) birds aged d 15 were used with 4 birds per replicate and 6 replicates in each treatment. In the CSM, 116 male AA birds aged d 15 were used. Among these 116 birds, 20 were selected as for initial data and 96 were assigned to 4 treatments with 6 replicate cages and 4 birds each. The linear regression between retained energy (RE) and metabolizable energy intake (MEI) or the logarithmic regression between heat production (HP) and MEI were used to calculate the metabolizable or net energy requirement for maintenance ($ME_m$) or $NE_m$, respectively. Results: The evaluation method did not detect any differences in the metabolizable energy (ME), net energy (NE), and NE:ME of diet, and in the MEI, HP, and RE of broilers. The MEI, HP, and RE of broilers decreased (p<0.01) as the feed intake decreased. No evaluation method${\times}$feed intake interaction was observed on these parameters. The $ME_m$ and $NE_m$ estimated from the linear relationship were 594 and 386 kJ/kg of body weight $(BW)^{0.75}/d$ in the ICM, and 618 and 404 kJ/kg of $BW^{0.75}/d$ in the CSM, respectively. The $ME_m$ and $NE_m$ estimated by logarithmic regression were 607 and 448 kJ/kg of $BW^{0.75}/d$ in the ICM, and were 619 and 462 kJ/kg of $BW^{0.75}/d$ in the CSM, respectively. Conclusion: The NEm values obtained in this study provide references for estimating the NE values of broiler diets.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.7
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• pp.1039-1048
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• 2007

Two experiments were conducted to determine whether leptin is a metabolic signal for gonadotropin secretion in ewes. In the first experiment, twenty-eight cyclic Chal ewes were assigned randomly to an energy restricted, no leptin group (ERNL) (60% of maintenance; n = 14) and an energy normal, no leptin group (ENNL) (100% of maintenance; n = 14) for 71 days (6 estrous cycles). Estrus was synchronized with seven consecutive injections of $PGF_{2{\alpha}}$ Biweekly, body weight (BW) and body condition score (BCS) were determined and blood samples were collected to measure plasma leptin concentration. Blood samples were also taken to determine plasma progesterone concentration twice weekly. After each PG injection from the second injection to the end of experiment, four ewes were selected and blood samples were collected at 20 minutes and at hourly intervals for 3 h to detect plasma LH and FSH concentration. In the second experiment, after the ceasing of the estrous cycle caused by energy restriction, six acyclic ewes were selected and randomly allotted to two groups (n = 3) and received the following treatment for four days. Ewes in an energy restricted, leptin group (ERL) were fed with a ration which provided 60% of maintenance energy requirements and intravenously injected with $4{\mu}g$ leptin/kg BW daily. Ewes in an energy excess, no leptin group (EENL) were fed with a ration that provided 180% (120%+60%) of maintenance energy requirements and intravenously injected with 1 ml saline daily. In both groups, blood samples were collected at 20 minutes and at hourly intervals for 3 h before feeding on d 0 and d 5, and for 3 h before and after injections as above on d 2 and d 4 to detect plasma LH and FSH concentration. In the first experiment, BW and BCS from the $2^{nd}$ estrous cycle, and leptin from the $3^{rd}$ estrous cycle to the end of the experiment significantly (p<0.05) decreased. In ERNL ewes, mean plasma concentrations of FSH significantly (p<0.01) decreased from the $4^{th}$ estrous cycle to d 71 and LH pulsatile secretion was suppressed on d 71, so that, mean plasma concentrations of LH (p<0.05), LH pulse frequency (p<0.01) and LH pulse amplitude (p<0.05) significantly decreased. In the second experiment, injection of leptin significantly increased mean circulating concentrations of LH (p<0.05), LH pulse frequency (p<0.01), LH pulse amplitude (p<0.05) and mean circulating concentrations of FSH (p<0.01) and leptin (p<0.01). High energy intake significantly (p<0.05) stimulated pulsatile secretion of LH and leptin secretion (p<0.01), but non-significantly increased plasma FSH concentration. The results of this study indicate that leptin is a metabolic signal for the GnRH-LH/FSH axis in feed-restricted fat-tailed ewes.

• Journal of Korean Society of Forest Science
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• v.83 no.2
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• pp.221-228
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• 1994

Respitation and growth rates of leaves, branches, stems and roots of 2 to 11-yr-old red pine trees(Pinus densiflora) were examined and applied to Thornley's growth equation, $$R=(\frac{1-Yg}{Yg})\frac{dW}{dt}+mW$$. The conversion efficiency of substrates(Yg), maintenance respiration coefficients(m), relative growth rates(${\mu}$) were estimated. The efficiency of conversion of substrates (Yg) was 0.3637g/g dw/yr and the maintenance respiration coefficient(m0 was 0.094g/g dw/yr. The relative growth rate(${\mu}$) was remarkably reduced with age from 0.90(2-year-old) to 0.33:11 year-old). The Ratio of gross respiration(R) per gross photosynthesis(Pg), R/Pg showed the range of 0.6~0.7 and annually 64% of Pg was spent for constructive respiration. The 3.4% of dry weight of whole tree was spent for maintenance respiration.

• Journal of Animal Science and Technology
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• v.45 no.1
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• pp.123-130
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• 2003

Metabolizable energy requirements for maintenance (MEm) of Hanwoo bulls were estimated in twelves metabolism trials using three different feeds at four stages of body weight(100, 200, 300 and 400kg). Three feeds were composed of 1) concentrates and rice straw, 2) concentrates and mixed grass hay, 3) concentrates and corn silage, respectively. Three energy levels were 1) maintenance (M) requirement, 2) 1.5 ${\times}$ M, and 3) 2.0 ${\times}$ M. All bulls were received 60% of their energy from concentrates and 40% form roughages. Three cattle for each trials fed different energy level were housed in metabolism stalls during the 5days of collection period, a total collection of feces and urine. Thereafter, during the 2days of respiration period the heat production was measured by indirect calorimetry using respiratory chamber. MEm were 99.80, 94.48, 94.80, and 97.68 kcal/W0.75 at 100, 200, 300 and 400kg. Mean value of MEm and efficiency of utilization ME for retained energy(Kg) were 95.80 kcal/W0.75 and 0.44.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.5
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• pp.749-760
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• 2017

Recently, the proportion of tunnel structures in roads and railways has increased rapidly. Along with this trend, the rate of occurrence of cracks and dropouts in concrete lining of tunnel structures is increasing. Generally, maintenance of such concrete lining is normalized and managed as the core of maintenance work in tunnel maintenance. However, the maintenance of the tunnel pavement is important in securing driver in the tunnel. In the design of tunnels, the underground condition of the tunnel is designed to be in good rock condition, so there have not been many cases of cracks in the tunnel pavement in the past. Recently, the construction of tunnel structures has been rapidly increased, and the length of the tunnels has become longer.Tunnel pavement installed in these ground conditions is increasing the occurrence of cracks in the pavement due to decrease of bearing capacity of the pavement after a long time. In this study, FWD and GPR were conducted to analyze the types of cracks and the reduction of bearing capacity in the tunnel.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.3
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• pp.1-11
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• 2023

After the collapse of the Seongsu Bridge in the 1990s in Korea, attention was focused on the maintenance of facilities. The government has established various policies since the enactment of the Act in 1995 until recently. In general, safety inspections are performed to evaluate the safety grade of facilities, and facilities are maintained and managed by performing repairs and reinforcements for defects. However, since the budget is limited, it is impossible to carry out repair and reinforcement projects for all defects. It is necessary to prioritize repair and reinforcement measures. Then, the priority index (PI) is presented considering the importance of members, the seriousness of defects, and economic feasibility. In this index, the degree of influence can be adjusted within the range of 50 to 100% according to the expert's subjective judgment, and the same weight is set for some specific members. Also, the effect through repair and reinforcement is not taken into account decisively, and most of them have a limit in which priority is determined by economic feasibility. Therefore, in this study, through several case studies, problems with the priority index were reviewed and an equation was presented to improve them.

• Journal of Korean Public Health Nursing
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• v.13 no.2
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• pp.131-142
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• 1999

The purpose of this study is to grasp the relationship between the amount of physical activities at work perceived by workers and their health promotion behaviors. To achieve such a purpose. this survey was conducted on 476 Workers who work for 3 food product work-sites located in Keong-in area by means of questionnaire from June 15 to July 14 . 1998. Collected data were statistically analyzed by SPSS/WlN. The significant results were obtained as follows. 1. The average scores of the amount of physical activities at work and health promotion behavior were 3.18 and 2.84 respectively; the former was slightly higher than moderate score 2.5 and the latter was almost the same as it. It can be interpreted that workers perceive their physical activities at work are heavier than their daily activities, which seems to make their health promotion behaviors still inactivated. 2. The amount of physical activities at work, it was were greater revealed that the more activities workers do after work. the more they walk and the more exercises they do. It implies that the voluntary practice of good health habit at leisure can be greatly contributed to the activation of more productive activity at work. 3. The amount of health promotion behaviors was larger as workers do more physical activities at work and have lower PIBW(Percent Ideal Body Weight). It means that the voluntary practice of good health habit is closely related to the degree of obesity and their positive attitude toward their work. Average PIBW was 106.71; most of the workers are distributed within the standard range in their weight. So we can presume that most of them are not seriously conscious of weight maintenance in their daily lives. Therefore it is desirable that health promotion program for workers should be developed toward connecting their physical activities at work with those in their daily lives much more. Physical activities, health promotion behaviors

• Korean Journal of Community Nutrition
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• v.6 no.1
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• pp.43-50
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• 2001

This study was conducted to compare the dietary characteristics of middle-aged people with different obesity index or food habits. Questionnaires were collected from 480 subjects in Daejon. The data were analyzed by $X^2$-test and ANOVA. The subjects were distributed into the normal weight group(66.3%), overweight group(18.3%) and underweight(15.4%) based on BMI. Twenty-five percent of males and 23.0% of females in the 50＇s belonged to the overweight group. The least consumed food was milk or milk products among the five basic food groups. The frequency of exercise was low in their daily life. The had better food habits than the males. The overweight group had worse food habits than the normal weight or underweight group. The underweight group ate light meal and ate slowly. The better the subjects had, the more regularly they took breakfast(p＜0.001). The good food habits group were more interested in their dietary life and were more careful in selecting foods for their health than the bad food habits group(p＜0.001). Based on the results of this study, the practical education programs should be focused on more intake of milk or products and on daily exercise for the self-health maintenance of middle-aged people. Also, proper education programs should be developed for males and females in their 50＇s to practice weight control and regularity of meals in their life, and to utilize nutrition knowledge in dietary life. Further research on the comparision of dietary characteristics are needed with consideration of the subjects ratio according to BMI.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.10
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• pp.1516-1521
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• 2008

This study was conducted to investigate the effects of different energy intake on physical and chemical composition in body fractions, growth performance and meat characteristics of finishing barrows and gilts. A total of twenty six crossbred (Landrace$\times$Yorkshire) consisting of 16 barrows and 13 gilts were used in this study. The animals were allocated by sex to two treatments to form a $2\times2$ factorial arrangement. The respective factors were sex (barrow and gilt) and dietary energy intake (1.8 and 3.0 times energy for maintenance). Pigs were kept in individual pens and had ad libitum access to feed and water from the start of the experiment at $52.4{\pm}1.9kg$ until they reached $109.9{\pm}4.4kg$ live weight. The growth performance, physical composition and meat characteristics of finishing pigs were not greatly affected by the sex. However, higher fat tissue weight in the carcass was observed in barrows compared with gilts (p<0.05). Higher proportions of water and protein (p<0.05), and lower lipid proportion (p<0.01) in the empty body and carcass were observed in gilts compared with barrows, while protein proportion in lean tissue was not affected by the sex. In fat tissue, only protein proportion was higher in gilts compared with barrows (p<0.05). Although, growth performance, physical and chemical compositions in body fractions were greatly affected, final body or carcass weight was partly affected by the energy intake In addition, loin characteristics such as shear force and loin eye area were partly influenced by energy intake levels. Therefore, the present results showed that growth performance and meat characteristics were not influenced but chemical body composition was greatly influenced by the sex. Growth performance, physical and chemical compositions in body fractions were greatly affected, whereas meat characteristics were partly affected by the energy intake levels.