• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.423-435
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• 1998

In this paper fatigue strength reduction of butt weld with penetration defect, which can be seen frequently in the steel bridge, was assessed quantitatively. S-N curves were derived and investigated through the constant amplitude fatigue test of fully or partially penetrated welded specimen made of SWS490 steel. The fracture mechanical method was applied in order to calculate the remaining fatigue life of the partially penetrated butt welds. The fatigue limit of the fully penetrated butt welds was higher than that of category A in AASHTO's fatigue design curves, and the slope of S-N curves with 5.57 was stiffer than that of other result for welded part generally accepted as 3. The fatigue strength of the partially Penetrated butt weld was strongly influenced by the size of lack of penetration, D. It decreased drastically with increasing D from 3.9 to 14.7mm. Fracture behaviour of the partially penetrated butt weld is able to be explained obviously from the beach mark test that a semi-elliptical surface crack with small a/c ratio initiates at a internal weld root and propagates through the weld metal. To estimate the fatigue life of the partially penetrated butt weld with fracture mechanics, stress intensity factors K of 3-dimensional semi-elliptical crack were calculated by appling finite elements method and fracture mechanics parameters such as C and m were derived through the fatigue test of CT-specimen. As a result, the fatigue lives obtained by using the fracture mechanical method agreed well with the experimental results. The results were applied to Sung-Su bridge collapsed due to penetration defects in butt weld of vertical member.

• Korean Journal of Ichthyology
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• v.11 no.1
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• pp.46-51
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• 1999

Age, hatching date and growth in length of juvenile Limanda yokohamae were determined by analysis of microstructure in otoliths. Monthly samples were collected by a beach seine in the shallow water off Gaduk-do from January to December, 1998. The juveniles were collected between February and April. Mean total length was $22.6{\pm}1.77\;mm$ ($\pm$SD) in February, $23.6{\pm}3.86\;mm$ in March, and $38.2{\pm}8.38\;mm$ in April. The core of otoliths ranged from 18 to $21\;{\mu}m$ in diameter and the growth increments were deposited concentrically from the hatching mark. The secondary growth layer began to appear at the 48 to 56-th increment. It indicates that L. yokohamae larvae may be completed the metamorphosis at this time of ca. 52 d after hatching, and moved into the shallow water for demersal stage. The hatching date calculated from the number of daily increments was between late November and early January, showing a peak in December. The total length (L, mm) was related to otolith radius (R, ${\mu}m$); L=0.055 R+5.81 ($r^2=0.88$). The growth in total length was represented by the Gompertz growth curve; $L_t=3.39e^{4.51(1-e^{-0.0067t})}$ ($r^2=0.81$). Daily growth rate was 0.35 mm/d at the age of 70 d and increased up to 0.55 mm/d at the age of 120 d.

• Journal of The Korean Association For Science Education
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• v.17 no.3
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• pp.261-271
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• 1997

This study evaluates on students' understanding and misunderstanding of homeostasis, classification of animals and plants, and food production in plants, and analyzes the teacher factor as a possible source of students' misconception. A total number of 863 students and 47 biology teachers at the middle and high school were randomly selected. Students' conceptions and misconceptions were measured with concept evaluation statements (CES) which was translated into Korean by author. The CES was developed and validated by Simson and Marek (1988). Teacher's misconceptions were investigated the way in which teachers marked students' work. The supposed answer given to the teachers to mark was based on misconceptions held by students tested in concept evaluation statements. The results of this study are as follows : 1. 0% of 7th Grade students, 4.5% of 9th Grade students and 5.4% of 11th Grade students understood homeostasis. There was a significant difference at the level of students' understanding of homeostasis according to schools and gender(P<0.05). Many students had a tendency of understanding the conception of the homeostasis by experiences and unscientific use of everyday language rather than a scientific concept. 2. 0.4% of 7th Grade students, 3.1% of 9th Grade students and 2.9% of 11th Grade students understood classification of animals and plants. There was a significant difference at the level of students' understanding of classification of animals and plants according to schools and gender(P<0.05). Students classified animals and plants through personal experiences and observations instead of trying to classify through microscopic analysis of animals and plants cell. 3. 1.2% of 7th Grade students, 10.3% of 9th Grade students and 19.4% of 11th Grade students understood food production in plants. There was a significant difference at the level of students' understanding of food production in plants according to schools and gender(P<0.05). Students had a misconception that food production in plants was done by an absorption of nutrients from soil not by photosynthesis. 4. A large proportion of teachers surveyed in this study appear to have misconceptions about homeostasis (38.1%), classification of animals and plants (34.1%), food production in plants (40.4%). The male teachers had. more misconceptions than female teachers(P<0.05). However, they didn't show any significant differences according to schools and teaching experience(P<0.05). 5. According to the investigation of teachers' perception, 29.8% of the teachers acknowledged that they might be a cause for students' misconceptions. This study shows that 38.3% of teachers did not understand the analyzed biological concepts precisely. By comparing the data of students and teachers, it turned out that teachers participate in the students' misconceptions. And teachers themselves acknowledged that students' misconceptions could be caused by them. Therefore. teachers' right understanding of fundamental biological concepts should precede to students' biology education. New training programs for biology teachers seem to be urgent.

• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1228-1232
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• 2000

Objective : This study was undertaken to analysis gamma knife radiosurgery(GKR) effect for trigeminal neuralgia after long term follow-up. Methods : There were 11 trigeminal neuralgia patients. The authors irradiated 67-85 Gy maximally to the nerve root entry zone(NREZ) using single 4mm collimator, just 1-6mm lateral side from the junction of the trigeminal nerve and pons. For the first 3 cases, we targeted the junction between the nerve and the pons. In theses cases, the pons was irradiated 56 or 60 gray in the surface. In the later 8 cases, the isocenter is positioned more distal side so that the brain stem surface would receive less than the 20% isodose. Results : The average follow-up duration was 25 months(13-50 months). Pain relief was noticed within a week to 5 months. In 3 patients, pain was relieved completely and in other 3 patients, mark improvement was achieved(80-90%). Remaining 4 patients showed significant improvement(30-50%). There was recurrence in only one case and she complained with similar intensity of pain at the last follow-up. There was no significant complication related to GKR. Conclusion : GKR is considered effective for trigeminal neuralgia based on the long term follow-up evaluation, but more clinical experience is needed to evaluate the efficacy of GKR for trigeminal neuralgia as a primary treatment modality.

• Journal of Chest Surgery
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• v.4 no.2
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• pp.69-80
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• 1971

Total body perfusion using Rygg-Kyvsgaard Heart-Lung-Machine, Mark IV, Polystan was attempted in the dogs by the hemodilution method with total prime of buffered Hartman's solution and under hypothermia. The first of all, the functions of Rygg--Kyvsgaard Heart-Lung-Machine and the effects of the hemodilution perfusion by buffered Hartman's solution was studied. At the same time the changes of blood pressure, oxygen consumption, and influence on the blood pictures were observed before, during, and in 1-3 days after perfusion. Hemodilution rates were the average 74. 22cc/Kg(the ranges of 67 to 81 cc/Kg) and perfusion flow rates were maintained in the mean 62. 6cc/Kg/min., Although it was possible to check up to 87 cc/ Kg/min. The total body perfusion continued for 60-80 minutes. Hypothermia was employed between $36^{\circ}C$ and $32^{\circ}C$ of the rectal temperature. Arterial pressure was ranged approximately between 68mmHg and 149mmHg, but generally, it was maintained over 80mmHg. Venous pressure was measured between 6.5cm $H_2O$and 11.5cm $H_2O$. Optimum oxygenation can be expected when oxygen flow into the disposable bubble oxygenator was maintained approximately at 3.5 L/min .. Inthis way, the oxygen contents were measured in the mean value of 13.11${\pm}$O.56 vol. % of arterial blood and 8.67+1.08 vol.% of venous blood(P${\pm}$0.86 vol.% in arteriovenous oxygen difference and 2. 97${\pm}$0.62cc/Kg in oxygen consumption were calculated. According to these dates, it is as plain as pikestaff that excellent oxygenation and good tissue perfusion was accomplished. Erythrocyte, hemoglobin and hematocrit were decreased about 38% during extracorporeal circulation and these were not recovered until 1-3 days after perfusion. These decrease was resulted from relatively high degree of hemodilution rate and no blood transfusion to compensate during these experimental studies. The platelets were also decreased about 76% during perfusion, but on the contrary, it was increased progressively after perfusion and in 1-3 days after perfusion was returned to the control level. Leucocyte were also decreased during perfusion, but it was increased progessively after perfusion and in 1-3 days after perfusion exceed the control level. This increase was resulted from postoperative infection of the wound, but its analysis were not changed significantly.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.4
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• pp.432-442
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• 2006

Statement of problem: One of common problems associated with dental implant is the loosening of abutment screws that retain the implants. Purpose : This study was performed to investigate the influence of abutment screw length and repeated tightening on screw loosening in dental implant. Material and method: Forty nine Hexplants (13mm length, 4.3mm diameter, Ti grade IV, Warantec. Co. Ltd. Seongnam, Korea) and cementation type abutments(straight abutment) and abutment screws (0.4mm/pitch) were divided into 7 groups, depending on abutment screw length. Each implant and abutment was tightened to 30Ncm by torque controller(MGT50, MARK-10 Inc., USA) and the removal torque values were measured during 10 consecutive closure/opening trials. Results and Conclusion: The results of comparing the removal torque value are as follows : 1. There is no significant difference in the removal torque value between groups in 10 consecutive closure/opening trials (p = 0.97). 2. If the fractured abutment screw is engaged in longer than 2.425 thread length, there is no significant difference in the preload between the fractured abutment screw and the new abutment screw when both are equally tightened to 30 Ncm. 3. The removal torque value in the 1st trial(24.510 Ncm) was lower than that in the 2nd, 3rd, 4th, 5th, 6th, 7th trials and the removal torque value in the 2nd trials(25.551 Ncm) was maximum and was decreased in 1311owing trials. The removal torque value in the 1st trial was significantly lower than that in the 2nd, 3rd, 4th trials and was significantly higher than that in the 8th, 9th, l0th trials(p<0.05). 4. In the 2nd, 3rd, 4th, 5th, 6th, 7th trials, the abutment screw was mainly influenced by settling effect and the higher preload was obtained In the 8th, 9th, l0th trials, the abutment screw was mainly influenced by adhesive wear and the progressively lower preload was obtained.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.393-401
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• 2009

About 50,000 hives of Bombus terrestris are used for pollination of tomato and other economical crops (fruit vegetables and fruit trees) in Korea. Therefore this study was conducted to find out the effective use of B. terrestris and its economic effect in the major beefsteak-tomato cultivation areas from February to August in 2008. The pollinating activities, rate of bite-mark and lifespan of B. terrestris's hive according to all beefsteak-tomato varieties (Super Momotaro, Zeus42, Mascara and Super Sunroad, 500 $m^2$, $9,600{\sim}12,000$plants) were apparent by regular supplement of pollen ($5{\sim}6g$/3 days) to the hive of B. terrestris. Especially, Super Momotaro and Super Sunroad variety were most distinctive in the effects by regular pollen supplement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3789-3793
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• 2010

To investigate accuracy of graduated scale of schematic retinoscope training eye(schematic eye) and induced effect when measured at off-axis from visual axis. Two skilled retinoscopist measured refractive power using retinoscope in random order. Seven schematic eyes from a single manufacturer were recruited and set to mark +4.00 to -6 diopter(+4, +3, +2, +1, 0, -1, -2, -3, -4, -5, -6). After introducing +2.00 diopter trial lens(50cm working lens), neutral distance was measured at 180 degree to estimate accuracy of scale, and refractive power measured at 0, 5, 10, 15 and 20 degree off-axis to see if any error was induced. According to the results measured by two specialists, in six of seven schematic eye, scale setting varied (p<0.05) and measured refractive power at 5, 10, 15 and 20 degree off-axis from visual axis were $-0.13{\pm}0.06$, $-0.29{\pm}0.06$, $-0.58{\pm}0.11$, and $-0.83{\pm}0.16$ diopter respectively. In some schematic eye, scale graduated on the schematic eye and scale measured by retinoscopy could be different and if retinoscopy is performed off-axis from visual axis, any measuring error can be caused.

• The Korean Journal of Community Living Science
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• v.23 no.3
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• pp.339-346
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• 2012

The quality characteristics of kochujang added with additives of different ratios of rice-nuruk (at 1:0.7, 1:1.0, 1:1.3) were studied. The kochujang was stored for 8 weeks at $20{\pm}3^{\circ}C$. The brix tended to increase by increasing mixing ratio of rice-nuruk in all treatments. It increased rapidly up to 4 weeks fermentation and then showed a slight change after 6 weeks. The more mixing ratio of rice-nuruk increased, the more salinity of samples decreased. The initial pH value of kochujang was 5.08-5.10., however, the pH value decreased to 4.82-4.83 after an 8 weeks of storage period. The initial acid value was 0.66-0.68 and increased from 0.66-0.68 to 0.87-0.89. It had slight reduction phenomenon in the sixth week. As the aging period passed, chromaticity such as $a^*$- and $b^*$-values decreased gradually except for $L^*$-value. The moisture content of samples decreased gradually by adding rice-nuruk. but increased by passing an aging period. The initial amino nitrogen content of sample was 304-315 mg%. It increased to 399-442 mg% during the aging period. As the aging period passed, the total cell number increased from 6.81 log CFU/mL to 7.01 log CFU/mL in the fourth week and then steadily decreased to 6.66 log CFU/mL in the eight week. Results of sensory evaluation show that, as more rice-nuruk was added, the kochujang received a lower mark. There was no significant difference in flavor in all treatments. Color and sweetness with increasing amounts of rice-nuruk showed the lowest score. Saltiness rice-nuruk at the ratio of 1:1.0 was the highest at 6.22 points. Texture scores decreased with increasing amounts of the rice-nuruk Based on these results, the overall acceptability of the 1:0.7 rice-nuruk treatment which received the highest score is considered excellent.

• Journal of the Korean Society of Costume
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• v.20
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• pp.151-167
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• 1993

The purpose of this study is to systematize the theory of the Fashion Marketing and merchandi-sing system as well as the strategy for the Mar-keting based on the related variable. Furthermore, this study deals with development of the mark-eting strategy to the relation between consumers and industry. The content conclusion on the research can be outlined as follows : 1. In order to inverstigate how the life-style of consumers affects their sense of fashion, awa-reness of brand, and decision making process of purchase, the life-style of women consumers is classified into 15 types. (1) Acording to the different life-style types, and important difference is found in the consum-ers' sense of clothes, a unique image of outfit and its own favorite image of womanliness. (2) The consumer's awareness of a particular brand has a reasonable relationship with their brand preference and possession of the brands. (3) Their is an important discrimination acco-rding to the life-style types in their brand awar-eness and preference and possesion of brands. (4) The consumers of each life-style type show noticeable difference in the decision making pro-cess of purchase including he motive of purchase, the source of information, the cause of purchase intention, price, the frequency of purchase and the degree of satisfaction of purchased goods. 2. The merchandising system and the market positioning among the fashion industry are compared and analyzed in the following terms ; (1-1) For the purpose of establishing the target market strategy, the industry uses unreasenalbe methods to analyze the life-style of the target customers and the real customers(36%) and the aging phenomenon of brands is remarkable : as much as 37% of brands show over 5 years-old age gap. (1-2) The price setting process depends highly on the cost-plus approach. (1-3) In color planning, too many colors are used in every season(the average number is 22.3) and the investigation of the consumers' favorite color is neglected. (1-4) The manufacturers of successful brands are much likely to employ the textile designer and allow them to develop the various fabrication. (1-5) The regular rate of sales in each season is extremely low(56.04%) : the rate of the succ-essful brands is relatively high at 65%, but that of the unsuccessful as low as 51%. (1-6) 47% of brands reveal the designer-orie-nted fashion merchandising system. The successful brands, on the other hand, show a high rate of merchandiser oriented system. (2) Since the brand positioning is highly cen-tered on each brand image, styles and target age, the new data are presented in this study for the new market development. (3) To set up the target market, the mapping of images between the differentiated market and the consumers is suggersted according to the market positioning of industry and 15 types of the life-styles of consumers.