• Journal of the Korea Concrete Institute
• /
• v.24 no.3
• /
• pp.275-283
• /
• 2012

Steel Plate for Rebar Connection was recently developed to splice rebars in delayed slab-wall joints in high-rise building, slurry wall-slab joints, temporary openings, etc. It consists of several couplers and a thin steel plate with shear key. Cyclic loading tests on slab-wall joints were conducted to verify structural behavior of the joints having Steel Plate for Rebar Connection. For comparison, joints with Rebend Connection and without splices were also tested. The joints with Steel Plate for Rebar Connection showed typical flexural behavior in the sequence of tension re-bar yielding, sufficient flexural deformation, crushing of compression concrete, and compression rebar buckling. However, the joints with Rebend Connection had more bond cracks in slabs faces and spalling in side cover-concrete, even though elastic behavior of the joints was similar to that of the joints with Steel Plate for Re-bar Connection. Consequently, the joints with Rebend Connection had less strengths and deformation capacities than the joints with Steel Plate for Re-bar Connection. In addition, stiffness of the joints with Rebend Connection degraded more rapidly than the other joints as cyclic loads were applied. This may be caused by low elastic modulus of re-straightened rebars and restraightening of kinked bar. For two types of diameters (13mm and 16mm) and two types of grades (SD300 and SD400) of rebars, the joints with Steel Plate for Rebar Connection had higher strength than nominal strength calculated from actual material properties. On the contrary, strengths of the joints with Rebend Connection decreased as bar diameter increased and as grade becames higher. Therefore, Rebend Connection should be used with caution in design and construction.

• Journal of Korean Society of Forest Science
• /
• v.102 no.2
• /
• pp.272-280
• /
• 2013

This study aims to develop a standard diagnostic table for management and administration that oak mushroom cultivators of forestry households can utilize. By diagnosing their current level of management with the table, the cultivators themselves will be able to grasp and address their operational challenges better. The table is composed of; questions on the status of forestry households; columns for a series of management performance indices, and; questionnaire with 4 categories and 20 subcategories to check the current level of management and administration by the households. In order to prepare the standard diagnostic table for oak mushroom management, 196 forestry households throughout 10 areas - Cheong-yang, Gong-ju, Bu-yeo and Seocheon in Chungcheongnam-do, Mun-kyung and Ye-cheon in Gyeongsangbuk-do, Jin-an in Jeollabuk-do, Jangheung and Jang-seong in Jeollanam-do, and Jeju Islands - were interviewed with and a total of 190 questionnaires were acquired and made use of in the result analysis. Then, the score on management level of each forestry household was determined in the way of aggregating scores from each subcategory. The overall average score of every household was calculated at 62.2 point with more than half of the respondents, 54.7%, belonging to the range of 60 to 80. When considered by regional groups, the average score of Jin-an was the lowest with 57.6 point while that of Jang-seong was the highest with 69.6 point. In case of the 'cultivation management' category, there were a lot of cultivators who expressed a negative awareness of the term 'pest control' because they had a tendency to think the term in connection with 'herbicides or pesticides'. So it is inevitable to adapt and modify existing groups and grades to make sure that the cultivators can make a right choice without confusing the concept 'pest control' with 'herbicides or pesticides'. Meanwhile, the average scores of 'management and administration' categories were mostly low. It was remarkable in these categories that forestry households in Jeolla province, which had remained in lower ranks in the other three categories, recorded higher scores than those in Chungcheong province, boasting a relatively high level of management and administration.

• Journal of Korean Home Economics Education Association
• /
• v.20 no.1
• /
• pp.85-100
• /
• 2008

This study attempted to analyze the contents of Practical Arts(Technology Home Economics)Textbooks written by the 7th national curriculum in a gender equity education. The objective of this study was to suggest some improvements which should be solved in terms of gender equity in Practical Arts, Technology and Home Economics education through analyzing their teaching and learning contents. Quantitative analysis were carried out for the objective of this study, Practical Arts(Technology Home Economics)Textbooks were divided into Technology and Home Economics fields. The pictures and illustration were analyzed in terms of sexual discrimination considering the social status and role. The analysis results were as follows. First, there were few cases of sexual discrimination in the texts. On the other hand, there were some cases of sexual discrimination in the pictures and illustration. Considering the results of some studies carried out in the 6th national curriculum, many problems raised in a gender equity education standpoint in the studies were solved. However, there were some cases of sexual discrimination which should be improved in the textbooks written by the 7th national curriculum. Second, there were few cases of sexual discrimination in Practical Arts textbooks. On the contrary many problems in terms of gender equity education were found in the textbooks of Technology and Home Economics. This result may be caused by the characteristics of Technology and Home Economics. The traditional viewpoint toward Technology and Home economics Textbook needs to be changed. In other words, their textbooks have to include practical contents for the positive sense of value and right sexual roles in terms of gender equity education. The contents of Practical Arts(Technology Home economics)Textbooks should be designed considering the articulation among the subjects and grades especially in terms of gender equity education.

• Journal of Bio-Environment Control
• /
• v.21 no.4
• /
• pp.336-342
• /
• 2012

Inorganic materials were commonly used as container media in domestic plant factories. Objective of this research was to secure the information in soil physical and chemical properties of inorganic materials such as vermiculites and perlites. To achieve this, 12 gold and silver vermiculites from China, Zimbabwe, and South Africa and 5 perlites from China were collected based on the marketing grades (MG) in particle sizes and analyzed for determination of their characteristics. The percentage of particles larger than $710{\mu}m$, in China perlite MG 3~5 mm, China silver vermiculites MG > 8 mm and MG 3~8 mm were 99.9%, 99.8%, and 99.7%, respectively, which were much higher than 28.4% in China gold vermiculite MG 0.3~1.0 mm, 14.0% in perlite MG < 1.0 mm, and 12.6% of Zimbabwe silver vermiculite MG < 1.0 mm. The container capacities of perlite MG < 1.0 mm and South Africa silver vermiculite MG 0.25~1.0 mm were 72.0% and 71.1%, respectively. The air space in China silver vermiculite MG 3~8 mm was 49.3% which was higher than other materials tested. However, the China gold and silver vermiculites MG 0.3~1 mm had 3.5% and 2.4% in air space indicating that possible problems could occur in soil aeration when they are used for container media. The percentage of easily available and buffering water of China gold vermiculite MG 0.3~1 mm and perlite MG < 1.0 mm were the highest among test materials. The ranges of pH and electrical conductivity were 6.36 to 10.7 and 0.032 to $0.393dS{\cdot}m^{-1}$ in vermiculites and 7.78 to 8.62 and 0.030 to $0.041dS{\cdot}m^{-1}$ in perlite, respectively. The cation exchange capacity of China silver vermiculite MG 0.3~1 mm were $14.7cmol{\cdot}kg^{-1}$ that was 10 times as high as $0.34cmol{\cdot}kg^{-1}$ in perlite MG 1~2.5 mm. The vermiculites had the higher contents of exchangeable cations such as Ca, K, and Na, than those of perlites.

• Journal of the Korean Society for Library and Information Science
• /
• v.17
• /
• pp.105-159
• /
• 1989

The purpose of this study is (a) to identify physical and content elements of children's books that seem to interest second and fifth graders to read, and (b) to observe how the influence of those elements on children's reading interest shifts as children develop. For the purpose of this study, children's books are classified into two groups: 'books of low preference' and 'books of high preference' as determined by second graders, and fifth graders' library circulation record in the library chosen as the sample for the present study. The physical and content elements of the books belonging to these two groups are analyzed and compared. Main findings and conclusions made in this study are summarised as follows: (1) The physical elements of children's books which have significant relationship with second graders' reading preference are illustration quantity, size of types, space between lines, and size of the book. (2) The content elements of children's books which have significant relationship with second graders' reading preference are the readability level of sentences, and the sex of heroes. (3) The physical elements of children's books which have significant relationship with fifth graders' reading preference are illustration quantity, illustration styles, and size of the book. (4) The content elements of children's books which have significant relationship with fifth graders' reading preference are the readability level, the sex of heroes, subject matters, themes and the environmental settings as the background of stories. (5) Reading preference of the pupils at the second and fifth grades are influenced by the quantity of illustration. Second grade pupils prefer reading books which contain a larger quantity of illustrations, whereas 5th grade pupils prefer books which contain less quantity of illustrations. (6) The relationship between second graders' reading preference and the illustration style are rejected at the $10\%$ significance level. A strong relationship, however, appears to exist between 5th graders' reading preference and the illustration style. The 5th grade pupils prefer more realistic illustrations, while cartoons and semi-abstract drawings do not appeal to them. (7) The type size, and space between lines which have had great influence on the book preference of 2nd grade pupils influence little on the 5th grade pupils book preference. (8) Second grade pupils prefer the book of a small Size, whereas 5th grade pupils whose reading taste has developed at a primary stage prefer the book of a large size beyond a certain standard. (9) Second grade pupils prefer reading books which can be easily read, whreeas 5th grade pupils prefer reading books containing difficult sentences. (10) Second grade pupils and the 5th grade pupils both prefer books in accordance with the sex of there heroes. (11) Relationship between second graders' reading preference and the subject matters are rejected at the 10% significance level. A strong relationship, however, appears to exist between 5th graders' reading preference and the subject matter. Fifth grade pupils prefer reading books of which the themes are mystery, exploration and adventure. (12) The theme of books is not proved to relate with the book preference of the 2nd grade pupils, but it is closely related with the book preference of 5th grade pupils. Fifth grade pupils prefer reading books which contain exploratory stories. (13) Second grade pupils are not influenced by the environmental setting of the story, but 5th grade pupils prefer reading stories with the environmental setting in the air. (14) The quantity of illustrations is the element influencing most on .the book preference of the 2nd grade pupils, followed by the space between the lines, which influences least on the book preference of the 5th grade pupils. (15) The physical element influencing most on the book preference of the 2nd grade pupils is the quantity of the illustrations. The physical element which has the most strong influence on the book preference of the 5th graders is illustration styles. (16) The content elements which has much influence on the book preference of the 5th grade pupils are certain kinds of characteristics of heroes. In case of the 2nd grade pupils book preference, striking evidence of such characteristics of heroes is not traced.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.5 no.1
• /
• pp.26-32
• /
• 2002

Purpose: Constipation in childhood is a significant problem, however, understanding of its epidemiology has been limited in Korea. The aim of this study was to investigate the prevalence and risk factors of constipation in school-aged children, helping to manage and prevent it. Methods: This cross-sectional, descripsive observational prevalence study included children (2grade, 1st and 6th grade) who were attending two elementary schools in Gwangju. The prevalence of constipation, associated symptoms, and risk factors were evaluated by questionnaire. A child was considered to be constipated when he or she defecated two or less times per week. Results: The prevalence of constipation was 15.4%. There is no significant difference between both sexes and grades. Of the causes of constipation, there was statistically significant difference in exercise deficiency, frequent intake of convenience food, long-time watching TV, unbalanced diet and enuresis history between constipation and normal group. Especially, long-time watching TV, exercise deficiency, and enuresis history were risk factors for development of constipation. Only 27.1% of children with constipation were treated by laxative and enema. Conclusion: Even though the prevalence of constipation was high, more than half of them was not treated at all. We should endeavor to educate the children and their parents to prevent constipation by evaluating the feeding and behavioral habit completely, and treating them properly.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.1
• /
• pp.30-40
• /
• 1995

The relationship between dietary intake and vitamin/mineral supplement usage was examined in 706 adolescent girls who were high school students. 43.8% of subjects used vitamin/mineral supplements during one year. The higher the family income and parents education level, the higher percentage of vitamin/mineral supplement usage was. But there was no significant difference between grades and scores. And vitamin/mineral supplement usage was higher int he thin and obese groups than the average weight groups. Nutrition knowledge and food habit did not affect vitamin/mineral supplement usage. Calorie intakes of vitamin/mineral supplement users and nonusers were similar. However, independent of the supplements, the diets of supplement nonusers contained significantly more dietary protein, vitamin A, vitamin $B_2$, niacin, vitamin C, and calcium than the diets of the users. A considerable portion of both the users and nonusers had dietary intakes of less than 2/3 of the Recommended Dietary Allowances for vitamin $B_1$, vitamin $B_2$, niacin, calcium, and iron. Vitamin/mineral supplement nonusers generally consumed a more vitamin, mineral from diet. Reasons for taking supplements were to take energy, advice and illness.

• Journal of Bio-Environment Control
• /
• v.28 no.2
• /
• pp.166-171
• /
• 2019

This study was conducted to investigate the effect of gaseous chlorine dioxide ($ClO_2$) concentration and treatment method for maintaining marketability in strawberries 'Maehyang' for export. After harvesting strawberry colored with $60{\pm}5%$ of the skin, and the gaseous $ClO_2$ was applied as four treatments in the cold store set with $10^{\circ}C$ which were as follows: i) non-treatment (Control), ii) $0.2mg{\cdot}L^{-1}$ for 30 minutes, iii) $0.4mg{\cdot}L^{-1}$ for 30 minutes, and iv) continuously exposed at $0.4mg{\cdot}L^{-1}$ during the storage period. Weight loss, firmness, soluble solids content, color, incidence of gray mold, and quality grade of strawberries were investigated every 3 days during 16 days storage in cold store. The weight loss was consistently high at $0.2mg{\cdot}L^{-1}\;ClO_2$ treatment, and the weight loss was lower than other treatments when gaseous $ClO_2$ was continuously treated. Firmness was significantly higher at 0.2 and $0.4mg{\cdot}L^{-1}$ $ClO_2$ treatment on the 13th day of storage. Soluble solids content tended to below in continuous gaseous $ClO_2$ treatment. The colors showed no tendency as affected by concentrations and treatment methods of gaseous $ClO_2$. No gray mold was observed in the continuous gaseous $ClO_2$ treatment until the 13th day of storage. The quality grade was lower in gaseous $ClO_2$ treatment group than in the control. As a result, it was possible to decrease the weight loss and the incidence of gray mold by continuously treating the gaseous $ClO_2$ to strawberry 'Maehyang' for export during the storage period after harvest. However, further research is needed on method to maintain quality grades of fruits.

• Journal of Korean Home Economics Education Association
• /
• v.33 no.3
• /
• pp.41-63
• /
• 2021

The purpose of this study was to investigate the nutritional knowledge and eating behavior of middle school students in Gwangju area in order to provide basic data for the development of home economics curriculum that can help the students form healthy eating habits. For this purpose, a self-administered questionnaire was distributed to middle school students in Gwangju area. A total of 330 questionnaires were collected by convenience sampling and analyzed using SPSS(Statistics Package for the Social Science) Version 20.0 for Windows. Results of this study are as follows. First, school curriculum session ranked top(31.82%) on the list of sources for middle school students to acquire nutrition knowledge. Second, the mean score of nutrition knowledge of all respondents was moderately high(14.33 points out of maximum 20 points). In terms of nutrition knowledge by gender, female students had a higher level of nutrition knowledge in the 'Food' domain than their male counterparts(p<0.05). With regard to nutrition knowledge by grade, Grade 9 showed a higher score than Grade 7 and 8(p<0.001). Third, the mean score of eating behavior of all respondents was at an average level(69.75 out of 100 points). In terms of eating behavior by gender, male students showed a higher score than their female counterparts(p<0.05). In particular, male students had higher scores than female students for the following items: "I exercise regularly after school"(p<0.001); "I regularly eat meal three times per day"(p<0.01); "I don't skip breakfast"(p<0.01); and "I don't eat sweet food often"(p<0.01). In terms of eating behavior by grade, Grade 9 showed higher scores than Grades 7 and 8 for the following items: "I eat meal out of thankfulness for those who have prepared food"(p<0.01) and "I eat grains for every meal"(p<0.01). Finally, with regard to eating behavior depending on the level of nutrition knowledge, the 'Upper' and 'Middle' groups had higher scores for eating behavior than the 'Lower' group, indicating that a lower level of nutrition knowledge resulted in a lower score in eating behavior. Based on the above results, home economics teachers responsible for dietary education should have a greater sense of mission and pride and make more efforts to improve nutrition knowledge and eating behavior of middle school students.

• Korean Journal of Environment and Ecology
• /
• v.36 no.5
• /
• pp.445-459
• /
• 2022

In this study, we investigated current vegetation and assessed the health of vegetation through the KERVI (Korea Estuary Riparian Vegetation Index) to monitor vegetation changes near estuaries due to the opening of the Nakdong River estuary. As the first investigation of the long-term monitoring, six areas near the Nakdong River estuary were surveyed twice in July and October 2021, and vegetation monitoring and a survey of species composition and distribution density of aquatic, riparian, and land plants were carried out. The survey identified 262 taxa, 82 families, 192 genera, 196 species, 3 subspecies, 26 varieties, and 1 form of vascular plants in the surveyed area. The results of the vegetation health assessment through KREVI showed that sites 1 and 6 were rated "Very good" in both surveys, sites 2 and 4 were rated "Very good" in the first survey and then "Good"in the second survey, and site 3 and 5 were rated one grade higher in the second survey than the first survey. The assessment showed that the health grades of most species in the survey area were generally high. Most of the potential natural vegetation after the opening of estuary gates to create a brackish water area is expected to consist of reed (Phragmites communisTrin.) communities. The area of the willow (Salix koreensisAndersson) community adjacent to the water area may be somewhat narrower, but the community will be maintained. In the case of freshwater areas in inland areas with very low salinity, reeds (Phragmites communisTrin.) are expected to occupy most of them, and some communities such as amur silver-grass (Miscanthus sacchariflorusBenth.) and cattails (Typha orientalisC. Presl) are expected to be distributed. We suggest establishing measures such as estuary gate operation to create healthy brackish water regions through long-term monitoring.