• 대한치과의사협회지
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• 제12권2호
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• pp.107-111
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• 1974

In order to collect some necessary data to promote correcting the toothbrushing technic on the Korean public, the author had examined the number of present teeth on which had cervical abrasion and the most basic home dental care in 2,000 Korean male and female adults from 19 to 52 years in the age. Then, the cervical abrasion experience rate and the cervical abrasion experience teeth rate were calculated and evaluated. The obtained results were as follows: 1. Cervical abrasion experience rate was 32.45% 2. Cervical abrasion experience rate was gradually increased by ageing. 3. Cervical abrasion experience rate in male adults was higher than that in female adults. 4. Cervical abrasion experience rate in the lower jaw was higher than that in the upper jaw. 5. Cervical abrasion experience rate of the teeth at the right side was higher than that of the teeth at the left side. 6. Cervical abrasion experience teeth rate was 3.82%. 7. Cervical abrasion experience rate was highest on the first bicuspid, and followed in the sequence of the second bicuspid, canine, first molar, incisors, and 2nd and 3rd molars.

• 상하수도학회지
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• 제30권1호
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• pp.77-85
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• 2016

The characteristics of filter/adsorber granular activated carbon (F/A GAC) were investigated by measuring various parameters, which include surface area, pore volume, abrasion number, floater, and water-soluble ash. The correlation between parameters was also evaluated. Moreover, rapid small-scale column test (RSSCT) was conducted for adsorption characteristics. Thirteen F/A GAC were tested, and the average values of abrasion number and water-soluble ash were 88.9 and 0.15%, respectively. F/A GAC with the larger external surface area and greater mesopore volume had the lower abrasion number, which indicated that it was worn out relatively easily. Water-soluble ash of coconut-based GAC (about 2.6%) was greater than that of coal-based GAC (less than 1%), and the pH of solution was increased with GAC, which had the higher water-soluble ash. On the other hand, floater of thirteen F/A GAC was divided as two groups, which one group had relatively higher floater (2.7~3.5%) and the other group had lower floater (approximately 0.5%). The results of RSSCT indicated that coconut-based GAC (i.e. relatively higher water-soluble ash) had less adsorption capacity. Moreover, adsorption capacity of coal-based GAC with larger surface area and greater mesopore volume was superior to others.

• 한국농공학회논문집
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• 제55권6호
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• pp.187-196
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• 2013

This study is focused on analyzing the deformation types of seaside armor stones based of field survey in order to establish the cause of abrasion following the deformation of seaside armor stones. 1. The deformation of seaside armor stone in saemangeum sea dike was classified as three different types: floating, deviation, and abrasion. 2. It was discovered that the stones floated to the extent of maximum 50 m, as the result of inspecting floating stones which were situated on different ten places. 3. The average number of deviation in the high ocean wave section was four times more than that in the ordinary ocean wave section, as a result of comparing the deviation number of the ordinary ocean wave section and that of the high ocean wave section for the purpose of inspecting the relation between the deviation of armor stones and the effects of ocean wave. 4. The angular shape of armor stones seen in the initial construction period has been abraded smoothly, as result of comparing of the shape change of armor stones for the purpose of inspecting abrasion state of seaside armor stones. 5. It was discovered that the abrasion of armor stone was severe in the section of many floating stones, as a result of analyzing the levels of abrasion and the cumulative sections of floating stones for the purpose of investigating the cause of abrasion.

• Journal of Information Display
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• 제12권4호
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• pp.173-177
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• 2011

The alignment film abrasion caused by the rubbing process was quantitatively evaluated via atomic-force microscopy (AFM). First, a patterned alignment film structure, which was molded through the imprint method, was artificially formed. Then, the surface topography of the alignment film was evaluated via AFM after rubbing, and the degree of abrasion of the alignment film was estimated by subtracting the value after rubbing from the value before rubbing. It was recognized that the degree of abrasion increased with an increase in the rubbing strength. The relationship between the number of rubbing cycles and the degree of abrasion of the alignment film was also estimated.

• 접착 및 계면
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• 제23권4호
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• pp.101-107
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• 2022

Adhesive joints have many advantages such as weight savings, corrosion and fatigue resistance and now developed even withstand of high impact and dynamic loads. However, an adhesion has cumbersome and complicated surface preparation processes. The surface preparation step is critical in adhesive joint manufacturing in order to obtain the prescribed strength for adhesive joints. In this study, it was attempted to simplify and reduce the number of surface preparation steps, and abrasion and rapid adhesive application (ARAA) process is developed for an alternative solution. The abrasion processes are performed only for creating surface roughness in standard procedures (SP), although the abrasion processes cause surface activation itself. The results showed that there is no need the long procedures in laboratory or chemical agents for adhesion. After the abrasion process, the attracted and highly reactive fresh surface layer obtained, and its effect on bonding success is observed and analyzed in this research, in light of the essential physic and adhesion theories. Al 6061 aluminum adherends and epoxy-based adhesives were chosen for bonding processes, which is mostly used in light vehicle parts. The adherends were cleaned, treated and activated only with abrasion, and after the adhesive application the specimens were tested under quasi-static loading. The satisfied ARAA results were compared with that of the specimens fabricated by the standard procedure (SP) of adhesion processes of high impact loads.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1990년도 가을 학술발표회 논문집
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• pp.113-116
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• 1990

This study is designed to analyze the variation of grading and shape of aggregate with the number of rotations of Los-Angeles abrasion machine, and is aimed to analyze the effect of slump and compressive strength of strength of concrete with the shape of coarse aggregate by the abrasion act.

• 한국임상수의학회지
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• 제9권2호
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• pp.483-488
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• 1992

This experiment was carried out to establish the grade of adhesion formation and changes of blood following artificial injuries such as abrasion, incision and electrocautery on colon and uterine horns in rats. 36 rats (abrasion-, incision-, electrocautery-treated groups) had laparotomy and abdominal injuries, twelve rats( control group) had only laparotomy, Ten days fellowing abdominal injuries, the score of adhesion formation and changes of blood were noted 1. Electrocautery-treated group was significant evident in adhesion formation in colon(p<0.01) and electrocautery and incision-treated groups were more evident than abrasion and control group in uterine horns(p<0.01) 2. Changes of erythrocytes number and PCV were tended to decrease during 5 days after operation, but recover normal level 10 days after operation. 3. Changes of leucocytes number were showed to significantly increase in electrocautery and incision-treated groups 5 days after operation. 4. The electrocautery-treated group was showed to significantly decrease in plasma protein and increase in plasma fibrinogen concentration.

• 치위생과학회지
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• 제18권3호
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• pp.164-171
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• 2018

To improve the oral health status of Korean people, it is necessary to encourage proper oral hygiene management habits, such as toothbrushing, through appropriate health promotion techniques. Therefore, the purpose of this study was to evaluate the removal of plaque and tooth abrasion using ultra-soft (filament 0.11~0.12 mm) and soft toothbrushes for toothbrushing. The plaque removal was performed using a dentiform and Arti-spray, and the Patient Hygiene Performance (PHP) index was calculated as the sum total score divided by the total number of surfaces. In the abrasivity experiment, according to the number of brushings, a micro Vickers hardness tester was used, and a sample in the range of 280~380 Vickers hardness number was selected. The number of toothbrushing stroke were 1,800 (2 months), 5,400 (6 months), 10,800 (12 months), and 21,600 (24 months). The tooth abrasion was measured using a scanning electron microscope. Statistical analysis was performed using IBM SPSS Statistics 22.0 and a p-value <0.05 was considered significant. According to the results, there was no statistically significant difference in the degree of plaque removal between ultra-soft and soft toothbrushes. The difference in tooth abrasion between before and after toothbrushing was found to be greater with the soft toothbrushes than with the ultra-soft toothbrushes. Therefore, the ultra-soft toothbrush not only lowers tooth damage by reducing tooth abrasion, but also shows a similar ability to remove plaque as soft toothbrushes.

• 복식
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• 제52권2호
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• pp.71-80
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• 2002

The purpose of this study was to examine the correlation between the shape of the foot and foot abrasion. and to provide preliminary data for shoe manufacturing by comparing the length of a woman's feet and the shoe size. The Martin calibrator and measuring tapes were utilized to measure the shapes of 163 female college students' feet. Indirect measurements were also obtained by line drawing of the feet for additional analysis. Brief questionnaires about what type of shoes are worn were given to the subjects of the study. Data analysis was presented by frequency, percentage, and standard deviations. Factor analysis and correlation co-efficiency of data was conducted on the significance level of p〈.05. The results of the study are as follows (1) The average number of days per week in which the subjects wear ladies' shoes per week were 4.5. Little over half of the subjects (53.87% ) answered that they wear heeled shoes for more than 8 hours per day. The most preferred height of a ladies'shoe heel was between 2 cm and 4 cm, as replied by 41.0% of the subjects. (2) The foot area where abrasion occurs most often was around the heel (51.2%) and the middle part of the sole (50.9%) (3) Factors correlated to the heel abrasion included the circumference and the breadth of the foot. The abrasion on the side of the first toe of mid-sized feet was most affected by the angle of the first the and inner foot line. The height of the foot heel was a significant factor for the abrasion near the anklebone. In conclusion, the abrasion resulted from the inappropriate fitting of the shoe and the foot. Also, the circumference and the width factors were more influential rather than the foot length. Therefore, more database on this should be systemized and available to the footwear manufacturers and the customers for more practical use of shoe size and public education.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.59-69
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• 2019

This paper focuses on the numerical simulation of ice abrasion induced by unbreakable ice floe. Under the assumption that unbreakable floes behave as rigid body, the Discrete Element Method (DEM) was applied to simulate the interaction between a fixed structure and ice floes. DEM is a numerical technique which is eligible for computing the motion and effect of a large number of particles. In DEM simulation, individual ice floe was treated as single rigid element which interacts with each other following the given interaction rules. Interactions between the ice floes and structure were defined by soft contact and viscous Coulomb friction laws. To derive the details of the interactions in terms of interaction parameters, the Finite Element Method (FEM) was employed. An abrasion process between a structure and an ice floe was simulated by FEM, and the parameters in DEM such as contact stiffness, contact damping coefficient, etc. were calibrated based on the FEM result. Resultantly, contact length and contact path length, which are the most important factors in ice abrasion prediction, were calculated from both DEM and FEM and compared with each other. The results showed good correspondence between the two results, providing superior numerical efficiency of DEM.