• Structural Engineering and Mechanics
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• 제84권4호
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• pp.561-573
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• 2022

This paper presents a new model to obtain the minimum area of the contact surface for rectangular isolated footings, considering that the contact surface works partially to compression (a part of the contact surface of the footing is subjected to compression and the other is not in compression or tension). The methodology is developed by integration to obtain the axial load "P", moment around the X axis "M_x" and moment around the Y axis "M_y". This document presents the simplified and precise equations of the four possible cases of footing subjected to uniaxial bending and five possible cases of footing subjected to biaxial bending. The current model considers the contact area of the footing that works totally in compression, and other models consider the contact area that works partially under compression and these are developed by very complex iterative processes. Numerical examples are presented to obtain the minimum area of rectangular footings under an axial load and moments in two directions, and the results are compared with those of other authors. The results show that the new model presents smaller areas than the other authors presented.

• Journal of Periodontal and Implant Science
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• 제31권3호
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• pp.625-631
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• 2001

The anatomic structure around interproximal area plays an important role not only in the natural teeth, but also in the implant. The loss of papilla can lead to cosmetic deformity, phonetic problem, food impaction on the anterior dentition, and masticatory problem, food impaction and proximal caries on the posterior dentition. The purpose of this study was to evaluate the relationship between interdental papilla existence and distance from contact point to alveolar crest in Korean posteior dentition. 45 Korean adult patients(31males, 14 females) participated in this study. Measurements were carreid out total 126 interproximal areas, 18 first premolar, 31 second premolar, 40 first molar, and 37 second molar areas. Papilla index was recorded as suggested by Jemt. Distance between contact point and alveolar crest measrued by Florida $probe^{R}$, after flap elevation. Each distance was measured 10 times by every 0.1mm unit. The results showed that the mean Papilla index 1.37 and mean distance between contact point and alveolar crest was 7.44mm. The correlation between the Papilla index and distance was high negative correlation(Pearson correlation=-0.47), and it was statistically significant(P=0.000) When the distance between contact point and alveolar crest was 5mm, the loss of papilla was appeared almost in half cases. When the distance was 6mm, the papilla loss was present 95%, when 7mm, the papilla loss was 100%.

• 대한화학회지
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• 제53권6호
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• pp.749-754
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• 2009

HEMA (2-hydroxyethyl methacrylate)는 친수성 안 의료용 소재로써 폭넓게 사용되고 있으며, 특히 소프트 콘택트렌즈 제조에 가장 많이 사용되는 재료중의 하나이다. 또한 산소투과율(Dk/t)은 콘택트렌즈 재료의 성능을 평가하기 위한 물리적 특성 중 매우 중요한 요소이다. 본 연구는 HEMA (2-hydroxyethyl methacrylate), MMA (methylmethacrylate), NVP (N-vinyl-pyrrolidone), 교차결합제인 EGDMA (ethylene glycol dimethacrylate)를사용하여 공중합 하였으며, 일반 콘택트렌즈와 칼라 콘택트렌즈를 제조하여 중심부와 주변부의 산소투과율을 polarographic method로 측정하였다. 실험 결과 polarographic method로 측정한 콘택트렌즈 주변부의 산소투과율 감소량은 40.77%에서 49.13%의 분포로 나타났으며, 칼라 콘택트렌즈는 염료에 기인된 영향으로 산소투과율의 감소량이 더 크게 측정되었다.

• 한국지역사회생활과학회지
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• 제25권4호
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• pp.495-510
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• 2014

This study examines the relationship between social support with adult children and neighbors on the life satisfaction of elderly individuals in rural areas. The analysis employed a sample of 764 elderly individuals residing in rural area. Data were analyzed through descriptive statistics, a chi-square test, a t-test, and a multiple regression analysis. First, the respondents reported moderate life satisfaction. Those respondents living alone were less likely to report life satisfaction than those with a spouse. Second, the respondents were more likely to be in contact with their neighbors than their adult children. Third, the respondents were more likely to receive social support from adult children than provide it to them. By contrast, the respondents were more likely to provide social support to neighbors than receive it from them. Fourth, economic status and contact with adult children and neighbors had signigicant effects on the life satisfaction of the respondents. Gender, religion, economic status, health status, increased contact with adult children, and instrumental support to neighbors had positive effects on the life satisfaction of elderly two-person household.

• 한국의류산업학회지
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• 제25권2호
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• pp.248-254
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• 2023

This study aims to measure the skin rigidity of different facial areas among Koreans and propose guidelines for each area's skin rigidity that can be applied with a facial robot for testing respiratory protective devices. The facial skin rigidity of 40 participants, which included 20 men and 20 women, aged 20 to 50, was analyzed. The rigidity measurement was conducted in 13 facial areas, including six areas in contact with the mask and seven non-contact areas, by referring to the facial measurement guidelines of Size Korea. The facial rigidity was measured using the Durometer RX-1600-OO while in a supine position. The measurement procedure involved contacting the durometer vertically with the reference point, repeating the measurement of the same area five times, and using the average of three values whose variability was between 0.4 and 4.2 Shore OO. The rigidity data analysis used precision analysis, descriptive statistics analysis, and mixed-effect ANOVA. The analysis confirmed the rigidity of the 13 measurement areas, with the highest rigidity of the face being at the nose and forehead points, with values of 51.2 and 50.8, respectively, and the lowest rigidity being at the chin and center of the cheek points, with values of 19.2 and 20.7, respectively. Significant differences between gender groups were observed in four areas: the tip of the nose, the point below the chin, the area below the lower jaw, and the inner concha.

• 대한임상검사과학회지
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• 제37권1호
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• pp.35-40
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• 2005

This paper reports the morphological nature of the remodelled interface process between implants and surrounding bone after 1, 4, 6, 8 and 12 weeks of implantation of smooth machined implants into rat tibias. After 4 weeks of implantation, histochemical analysis showed that the new bone was growing in direct contact with the implant. In the forming process, the activatived osteoblast cells migrated toward the interface and colonized the surface at the contact areas. This immature woven bone, rich in osteocyte lacunae, was deposited directly onto the implant surface. Osteoblast activity was found to continue ill 12 weeks of implantation The osteoblasts in lacunar areas developed numerous processes and synthesized bone matrix, after all, surrounded by secreting matrix. At the 12th week, the amount of newly formed bone matrix between bone and implant increased in mineralization. The mineralized mature bone contained well organized collagen fibers with characteristic banding pattern bone tissue formation around the implant.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.115-115
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• 2010

This paper introduces a measurement system that measures behavior and electrical characteristics of overhead contact line irregular sections in real-time. For verification, we developed a prototype of the real-time overhead contact line irregular section behavior measurement system and a monitoring system for field tests. The current and temperature of contact wires and messenger wires were measured real-time by applying the system at KTX a commercial line. Therefore, acquiring data is possible with the developed system and this system that measures one of the fundamental and key factors, the catenary current, should be applicable to various areas such as detecting characteristics for designing overhead contact lines, enhancing speed, and enhancing energy.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.129-132
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• 2005

This study analyzes the behavior of adhesion and friction according to the pore size of nanohoneycomb structures in atomic force microscope (AFM). Anodic aluminum oxide (AAO) films are fabricated as nanohoneycomb structures. According to the pore diameters of the nanohoneycomb structures, the adhesive forces and the frictional coefficients arc obtained in AFM, and the behaviors are analyzed in the view of the contact area between the sphere particle and nanohoneycomb substrate. The effective Young's moduli of the nanohoneycomb structures are measured from the nanoindentation tests, and the contact areas at zero applied load are calculated by combining the porosity of the nanohoneycomb structures and the contact radius determined from JKR and DMT theory.

• The International Journal of Costume Culture
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• 제7권2호
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• pp.151-157
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• 2004

This research is to conservate the old hat and restore its shape and place it on a supportive form in a stable protective container. The hat is a homemade construction, utilizing three different machine made laces, and two cotton net fabrics. The exterior, particularly the top crown piece, as well as the lace along the brim's edge has been generally soiled and discolored. Inside the crown, the cotton net has broken threads, and thread loss in several areas. The paper covering the two wires is very weak, and has discolored the lace in the areas of contact. The plastic buckles of the velvet ribbon have also discolored the areas where there is contact. The wash/bleach bath procedure was very effective. Virtually all of the light brown surface discoloration stains were removed. The darker brown spots, particularly concentrated around the two paper covered wires and assumed to be rust, were $90\%$ removed by the treatment. The brown spots apparently were due to the degradation of the paper covering, and not caused by the wire itself. The buckram foundation lost about $50\%$ of its stiffness, but this was not a major concern due to the fact that this hat should remain it its mount, which has been designed to serve for both storage and exhibition purposes.

• Nuclear Engineering and Technology
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• 제47권4호
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• pp.488-499
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• 2015

Acceleration sensors are usually used to measure the vibration of a structure. Although this is the most accurate method, it cannot be used remotely because these are contact-type sensors. This makes measurement difficult in areas that cannot be easily approached by surveyors, such as structures located in high or dangerous areas. Therefore, a method that can measure the structural vibration without installing sensors is required for the vibration measurement of structures located in these areas. Many conventional studies have been carried out on non-contact-type vibration measurement methods using cameras. However, they have been applied to structures with relatively large vibration displacements such as buildings or bridges, and since most of them use targets, people still have to approach the structure to install the targets. Therefore, a new method is required to supplement the weaknesses of the conventional methods. In this paper, a method is proposed to measure vibration displacements remotely using a camera without having to approach the structure. Furthermore, an estimation method for the measurement resolution and measurement error is proposed for the vibration displacement of a cylindrical structure measured using the proposed measurement method. The proposed methods are described, along with experimental results that verify their accuracy.