• Title/Summary/Keyword: Multiple contact

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A study on friction and stress analysis of wedge mount leveler in Semi-Conductor Sub-Fab (반도체 Sub-Fab 용 웨지 마운트 레벨러(Wdge Mount Leveler)의 마찰과 응력에 관한 연구)

  • Min, Kyung-Ho;Song, Ki-Hyeok;Hong, Kwang-Pyo
    • Design & Manufacturing
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    • v.11 no.2
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    • pp.25-28
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    • 2017
  • Semiconductor equipment manufacturers desire to enhance efficiency of Sub Fab to increase semiconductor productivity. For this reason, Sub Fab equipment manufacturers are developing Integrated System that combined modules with multiple facilities. Integrated System is required to apply Mount Leveler of Wedge Type in compliance with weight increase compared with existing single equipment and product shape change. This thesis analyzes main design variables of components of Wedge Mount Leveler and carries out structure analysis using ANSYS, finite element analysis program Analysis shows that main design variables of components of Wedge Mount Leveler has self-locking condition by friction force of Wedge and adjusting bolt. Each friction force hinges upon Wedge angle and Friction Coefficient of contact surface and upon the thread angle and Friction Coefficient of contact surface. Also, as a result of carrying out structure analysis of Wedge Mount Leveler, deflection and stress appears in different depending on the height of the level.

Finite element modeling of concentric-tube continuum robots

  • Baek, Changyeob;Yoon, Kyungho;Kim, Do-Nyun
    • Structural Engineering and Mechanics
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    • v.57 no.5
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    • pp.809-821
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    • 2016
  • Concentric-tube continuum robots have formed an active field of research in robotics because of their manipulative exquisiteness essential to facilitate delicate surgical procedures. A set of concentric tubes with designed initial curvatures comprises a robot whose workspace can be controlled by relative translations and rotations of the tubes. Kinematic models have been widely used to predict the movement of the robot, but they are incapable of describing its time-dependent hysteretic behaviors accurately particularly when snapping occurs. To overcome this limitation, here we present a finite element modeling approach to investigating the dynamics of concentric-tube continuum robots. In our model, each tube is discretized using MITC shell elements and its transient responses are computed implicitly using the Bathe time integration method. Inter-tube contacts, the key actuation mechanism of this robot, are modeled using the constraint function method with contact damping to capture the hysteresis in robot trajectories. Performance of the proposed method is demonstrated by analyzing three specifications of two-tube robots including the one exhibiting snapping phenomena while the method can be applied to multiple-tube robots as well.

Development and Application of Non-Contact Rock Fall Detection System utilizing Photo Sensor and Camera (광센서와 카메라를 활용한 비접촉식 낙석감지 시스템 개발 및 적용)

  • Jung, Yong-Bok;Song, Won-Kyong;Kim, Bok-Chul;Kim, Myung-Jin
    • Tunnel and Underground Space
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    • v.20 no.3
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    • pp.207-216
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    • 2010
  • Rockfall monitoring systems generally used in the country are mainly based on the detection of tension of protection wire or tilting of protection post due to rock fall. However, rock fall protection net must be installed prior to the monitoring system and continual maintenance work after each rock fall event is required for a normal operation of these detection systems. To solve these problems, we suggested and implemented a non-contact rock fall detection system using multiple photo sensors and additional camera. After a laboratory experiment and field application, we can conclude that this system is effective and reliable for detecting, collecting and analyzing the rock fall information. In addition, lighten and difference operations on two captured images were able to yield rough estimation of size and direction of rock fall.

The Effects of undergraduate students' Attiitudes toward the elderly and aging on grandmother-grandchild intimacy (대학생의 노인과 노화에 대한 태도가 조모와의 친밀감에 미치는 영향)

  • Lee, Shin-Sook
    • Korean Journal of Human Ecology
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    • v.16 no.3
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    • pp.479-490
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    • 2007
  • This study examines undergraduate students' intimacy toward the grandmother and their attitudes toward the elderly and aging. The study also identifies the variances that influence undergraduate students' intimacy toward the grandmother. The subjects were 397 undergraduates. Statistical analysis was conducted to examine frequency, percentage, mean, standard deviation, Cronbach's ${\alpha}$, t-test, Duncan test, ANOVA, and stepwise multiple regression. The results of this study were as follows; 1) The undergraduates' attitudes were mid-range, but their intimacy level toward their grandmother was high. 2) The undergraduates' intimacy level toward the grandmother differed significantly according to gender, experience of cohabitation, the presence of her, and religion, and it showed a significant correlation with attitudes toward the elderly and aging traits, period of cohabitation, and frequent contact with the grandmother. The undergraduates' intimacy level toward grandmother-in-low, however, was significantly different according to the religion. There was also had a significant correlation with the undergraduate students' attitudes toward the elderly and aging traits. 3) The variables that affect the undergraduates' intimacy level toward the grandmother were attitude, frequency of contact with the grandmother, gender, period of cohabitation, experience of cohabitation, and the presence of the grandmother, which explained about 35% of total variance. Attitudes toward the elderly and aging traits were very important variables for undergraduates' intimacy with their grandmother. The undergraduates' intimacy toward grandmother-in-low was affected by the variables of attitude, religion, experience of volunteer, frequency of contact with the grandmother, gender, and the presence of grandmother, which explained about 24% of the total variance. Attitude toward the elderly and aging traits were the most important variables for undergraduates' intimacy with their grandmother-in-low.

Elastic Behavior of Contact Lense(I) : Effect of Vibration (콘택트 렌즈의 탄성에 관한 연구(I) : 진동에 의한 영향)

  • Kim, Dase-Soo
    • Journal of Korean Ophthalmic Optics Society
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    • v.4 no.2
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    • pp.1-16
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    • 1999
  • Differential equations and its numerical solution program using Turbo-C were formulated to describe the radical distribution and average displacement amplitude of vibrating dehydrated contact lens(HEMA) driven by sinusoidal or rectangular pressure. The natural resonant frequency of the lens diaphram(thickness 0.08mm, diameter 14mm, curvature radius 8mm) was measured to be 5730 Hz from the extrapolation of frequency vs addedmass to the diaphram curve. The Young's modulus of the lens was measured to be $4{\times}10^9$ Pa with altering the original shape. The effect of parameters such as thickness, effective radius, damping coeff., amplitude of driving pressure on the vibration characteristics was illustrated by the computer simulation of the derived program. When the frequency of driving pressure coincides with the integral multiple of fundamental resonance frequency of the lens the wave pattern changes from arc to bell-shape along the radial position of the diaphram. If this happens to the contact lens on the cornea in vivo, it might create the feel of pull of the lens due to the increased rise of central part of the lens.

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Anaphylactic Shock in a Breast Milk-Fed Infant due to Skin Contact with Egg White (모유 수유아에서 발생한 계란 흰자 피부접촉에 의한 아나필락시스 쇽 1례)

  • Kim, Eo Jin;Yoon, Young Ran;Yeom, Jung Sook;Kim, Jum Su;Seo, Ji Hyun;Lim, Jae Young;Choi, Myoung Bum;Park, Chan Hoo;Woo, Hyang Ok;Youn, Hee Shang
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.7 no.1
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    • pp.83-86
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    • 2004
  • Food allergy is not uncommon among small children. Cow milk and eggs are most frequently incriminated as the major cause of food allergy. A 4-month-old female infant who did not have a previous history of contact with the egg developed anaphylactic shock when an emulsion of raw egg white was rubbed on the buttock by her mother to relieve erosive diaper dermatitis. She had been fed on breast milk. She had no past medical history of any other allergy and no family history of atopy, asthma or allergic rhinitis. Her IgE PRIST was 29.46 IU/ml and multiple antigen simultaneous testing chemiluminescent assay for food specific IgE antibody showed a level 4 positive value only to egg white.

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Health Belief Model Approach to Health Beliefs, Attitude, and Health Behaviors Concerning HIV / AIDS. (건강신념모델을 적용한 AIDS 예방의 건강신념, 태도 및 건강행동)

  • 김명혜
    • Korean Journal of Health Education and Promotion
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    • v.14 no.2
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    • pp.125-147
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    • 1997
  • This study was conducted in order to identify the extent to which Health Belief Model (HBM) constructs explain the likelihood of taking preventive behaviors for AIDS among the young adolescents in Korea. HBM was applied as the theoretical framework for developing questionnaire items in this study. The survey instrument included all of the constructs of Health Belief Model, namely, perceived susceptibility, perceived severity, perceived benefit, perceived barriers, cue to actions for preventive behaviors concerning AIDS. Additionally, demographic characteristics of the respondents, their sexual experiences, and AIDS Knowledge Test were included in the study. Each of HBM constructs were developed with a 5-point Likert type scale from l(never agree) to 5 (absolutely agree). The survey was conducted with a total of 247 military men in a city on September 18, 1996, using self-reported questionnaire. The results of the study were summarized as follows: 1. Because the subjects for this study were military soldiers, their demographic characteristics were limited to all men, young age, and ummarried. Educational status was evenly distributed between high school graduates and university students. 2. On the average, the respondents started their first sexual relationship at 18 years old and 82.6% of them did not use condom when having their first sexual experience. Thirty-one percent of the subjects had sexual contact with prostitutes and the average number of sexual contact with prostitutes was 5 times during the past 2 years. 3. The results of AIDS Knowledge Test scores demonstrated that the respondents had a high level of knowledge about AIDS. However, some misconceptions about transmission of AIDS through casual contact were still prevailed. Sixty-six percent of the respondents expressed that people infected with HIV should be isolated from the society in order to protect the general public. 4. All the respondents expressed that they had heard about AIDS before. TV was found to be the source which provided information on AIDS most frequently. 5. Among fundamental constructs of Health Belief Model, scores of perceived benefit of taking preventive action against AIDS marked the highest score, while scores of perceived susceptibility were the lowest. As a result of Multiple Stepwise Regression analysis, 13 variable groups were found to predict the preventive action by 25%. Among them, only perceived benefit variables was the most significant factor to explain preventive behaviors by 17%.

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Fabrication of Bump-type Probe Card Using Bulk Micromachining (벌크 마이크로머시닝을 이용한 Bump형 Probe Card의 제조)

  • 박창현;최원익;김용대;심준환;이종현
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.3 no.3
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    • pp.661-669
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    • 1999
  • A probe card is one of the most important pan of test systems as testing IC(integrated circuit) chips. This work was related to bump-type silicon vertical probe card which enabled simultaneous tests for multiple semiconductor chips. The probe consists of silicon cantilever with bump tip. In order to obtain optimum size of the cantilever, the dimensions were determined by FEM(finite element method) analysis. The probe was fabricated by RIE(reactive ion etching), isotropic etching, and bulk-micromachining using SDB(silicon direct bonding) wafer. The optimum height of the bump of the probe detemimed by FEM simulation was 30um. The optimum thickness, width, and length of the cantilever were 20 $\mum$, 100 $\mum$,and 400 $\mum$,respectively. Contact resistance of the fabricated probe card measured at contact resistance testing was less than $2\Omega$. It was also confirmed that its life time was more than 20,000 contacts because there was no change of contact resistance after 20,000 contacts.

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A Study on Microbial Contamination of Foods Exposed to Multiple Environments

  • KIM, Dan-Bee;CHA, Seong-Soo
    • The Korean Journal of Food & Health Convergence
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    • v.5 no.3
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    • pp.35-40
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    • 2019
  • In this study, general bacterial counts and coliform counts, which are hygienic indicator microorganisms, were tested for candy, chocolate, and jelly which are easily available and enjoyed around. After dropping each sample on the desk, indoors, and outdoors, it is immediately collected, or washed and collected to confirm the myth of the 3-second rule. Immediately after removing the wrapping paper, each sample was dropped on the desk, indoors, and outdoors, and after 3 seconds from the moment of contact with the surface, and then collected in a sample bag using sterilized sanitary gloves. After the same operation, each sample was rinsed for 5 seconds using sterilized sanitary gloves and sterilized distilled water, and then collected in a sample bag. The number of bacteria detected in non-washing candies was 41 CFU/g at outdoor and the number of bacteria detected in non-washing chocolate was 76 CFU/g at outdoor. The number of bacteria detected in non-washing jellies was 79 CFU/g at outdoor. Coliform group was not detected in all samples. This showed good results at the level of m = 10,000 or less, which is an allowable value suggested in the Food Code. Also, effect of washing on contaminated food was confirmed. This result is remarkably low compared with the microorganism specimens shown in Food Code, and it is confirmed that contamination occurs but not high value. Therefore, the myth of the 3-second rule is true compared to the figures based on Food Code. However, it showed the characteristics of bacteria that could survive and cross-contaminate on dry food surfaces and emphasized the importance of hygiene through food contact to unsanitary surfaces to minimize the risk of food poisoning.

A study on considerations when purchasing nail products and the nail beauty-related characteristics of beauty major students (미용전공 학생들의 네일미용 관련 특성과 네일제품 구매 고려요소에 대한 연구)

  • Seol, Hyun Jin
    • The Research Journal of the Costume Culture
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    • v.30 no.5
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    • pp.703-716
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    • 2022
  • This study was conducted with students who had experience in purchasing nail products asa result of by taking the nail design course of the department of beauty at a junior college. The purpose of this study was to provide useful information to nail companies, including the importance of product elements and effective media promotion, to support the planning and promoting of nail products for beauty major students. Means analysis, one-way ANOVA, and multiple regression analysis were conducted on detailed characteristics related to nail beauty (degree of nail management, degree of contact with nail beauty media) and considerations for the purchase of nail products. The results were as follows: For beauty major students, it was concluded that the greater the interest in nail beauty, such as degree of nail management and degree of contact with nail beauty media, the greater the interest in product quality, purpose, and safety, which are practical product elements considered when purchasing nail products. It was also confirmed that Instagram and YouTube advertising media have a significant effect on promoting nail product brands for beauty major students. As the subjects of this study comprise beauty major students in their early 20s, there is a limit to expanding and applying the conclusions of this study to general nail product consumers. Therefore, in subsequent studies, analysise of a wider range of nail product consumers should be conducted through an expanded sampling method.