• 한국정밀공학회지
• /
• 제32권9호
• /
• pp.799-805
• /
• 2015

The further development of information, communication and digital media technologies requires the use of advanced, miniaturized semiconductor chips that operate at a high frequency. Die bonding and wire bonding methods for semiconductor packaging have been replaced by direct attachment to the substrate after forming a bump on the chip. However, the height of the bump or ball is an important factor for defects during assembly. This paper proposes an algorithm to measure the height of the bumps or balls in semiconductor packaging with greater accuracy. The performance of the proposed algorithm is experimentally validated. Non-contact 3D measurements of a shiny round ball is quite difficult, and it is not easy to obtain accurate data. This paper thus proposes an optical method and technique to improve the measurement accuracy.

• 구강회복응용과학지
• /
• 제33권1호
• /
• pp.55-62
• /
• 2017

무치악 환자를 수복할 때 임플란트 피개의치를 이용한 치료법은 전통적인 총의치의 문제점인 저작시 동통, 의치의 부족한 유지와 안정을 포함하는 기능저하 문제 등을 해결할 수 있는 방법이다. $Locator^{(R)}$ (Zest Anchors LLC, Espandido, USA) 어태치먼트는 임플란트 피개의치에 사용되는 어태치먼트 중 수직적으로 필요한 공간이 가장 적고, 나일론 부품에 따라 유지력 조절이 용이하다. 하지만 Ball이나 Bar에 비해 기능시 부품의 마모로 유지력이 빠르게 감소하는 특징이 있어 가급적 임플란트 간 각도가 최소가 되도록 식립하려는 노력이 필요하다.

• 대한치과보철학회지
• /
• 제38권5호
• /
• pp.724-743
• /
• 2000

One of the biggest clinical problems of osseointegrated implant prosthesis is the excessive stress caused by bite forces which are transfered directly into the bone through the osseointegrated implant fixtures. So several biodynamic problems occur when there is an excessive fatigue stress. The factors of stress distribution are the number, kind, position, arrangement of the implants, and the distance between the implants, and the kind, quality of superstructure prosthesis and connection type between the rest implant and the superstructure. Recently, a distal short additional implant, socalled rest implant, is employed to reduced the stresses in conventional cantilevered prostheses. This study was undertaken to analyze the stresses transfered by osseointegrated implant cantilevered prostheses depending upon the number and the position of implants, the presence of rest implant, and the type of their connection. Three dimensional finite element analysis was attempted using ANSIS ver. 5.3 program under IBM INDIGO computer. The results were as follows : 1. The rest implant influenced on the pattern of stress distribution on the anterior area of the mandible and the superstructure. 2. In the group employing the rest implants, the fixed type of connection between the rest implant and the superstructure was more stable than the ball attachment type on the stress distribution. 3. In the group employing the ball attachment between the rest implant and the superstructure, the case with 4-implants(on canine, premolar) was little more stable than the case with 6-implants and the case with 4-implants(on incisor, premolar) on the stress distribution. 4. In the cantilevered group, the case with 4-implants(on incisor, premolar) and the case with 6-implants were more stable than the case with 4-implants(on canine, premolar) on the stress distribution. 5. In all of the group, the case with 6-implants and the fixed type of connection was the most stable and the case with 4-implants (on canine, premolar) was the most unstable on the stress distribution.

• 구강회복응용과학지
• /
• 제30권2호
• /
• pp.176-183
• /
• 2014

심하게 흡수된 치조제는 기능적인 하중을 견디기 어렵고 구강 조직의 유해 변화와 더불어 환자의 의치 적응을 어렵게 한다. 환자의 불편감을 해소하고 의치의 안정성과 유지력을 증가시키기 위해 임플란트를 이용한 피개의치가 치료 방법으로 선택될 수 있다. 로케이터 부착장치는 사용상의 편리성이 높으며 다양한 유지력을 갖는 남자부를 보유함으로써 임상에서 볼 형태 부착장치대용으로 많이 사용되고 있다. 본 증례는 77세 여자환자로서 낮은 수직고경과 심한 치조제 흡수를 보이는 상하악 무치악 상태였다. 이에 하악에 4개의 임플란트를 식립하고, 상악은 총의치, 하악은 로케이터 부착장치를 이용한 임플란트 피개의치로 수복하여 기능 및 심미적으로 만족할 만한 결과를 얻었기에 이를 보고하고자 한다.

• Advances in concrete construction
• /
• 제5권2호
• /
• pp.173-182
• /
• 2017

This paper is aimed at determining the shear and impact strength of waste plastic fibre reinforced concrete. M30 grade of concrete is prepared with waste plastic door fibres cut into 5 mm width and aspect ratios of 30, 50, 70, 90 and 110. Fibres are used in a volume fraction of 0 to 1.5% with an increment of 0.25%. L shaped specimens are cast for shear strength tests and flat plates of size $250{\times}250{\times}30mm$ are used for impact tests. "Drop ball method" is used for checking the impact strength. Shear strength is checked with L shaped specimens under UTM with a special attachment. It was found that up to 1.25% of waste plastic fibres can be effectively used for better strength of concrete both in shear and impact. Shear and impact strength were found to be increasing up to a volume fraction of fibres of 1.25%.

• 복식문화연구
• /
• 제29권6호
• /
• pp.779-794
• /
• 2021

In this study, the sales status of female ball-jointed dolls and their parts were investi- gated and analyzed. Baseline data from 194 products and 54 brands on domestic and international Internet sites was gathered for the manufacture of ball-jointed dolls and the development of prototype costumes for them. The results are as follows. First, the sizes used for ball-jointed dolls are SD, USD, MSD, 13SD, and 70SD together with height. This study analyzed 39 sizes (15~70cm) by classifying them into numbered groups: 1 (15~22cm), 2 (23~33cm), 3 (35~51cm), 4 (53~62cm), and 5 (63~70cm). The price varied depending on the size; for example, 50cm dolls were approximately 45,000 won, while limited editions were sold at high prices, regardless of their size. They were classified into designs according to their body proportions and facial features as follows: 7- or 8-head-figure, 5-head figure, and 3-head figure, and were presented proportionally as images of women, adolescents, and infants. Second, the head was incised so that the top could be removed horizontally or the facial region vertically, allowing attachment of the eyeballs (which were either glass, resin, or acrylic) to the inside. More than 30 different colors were sold. Various wig styles were provided, including cut, short hair, and perm. These were made from human hair, heat-resistant fiber, and artificial hair. For the hands, there was a design expressing human hand gestures. For the feet, heels were in the form of wearing either high-heels or flat soles.

• The Journal of Advanced Prosthodontics
• /
• 제4권4호
• /
• pp.254-258
• /
• 2012

Implant-supported overdenture is a reliable treatment option for the patients with edentulous mandible when they have difficulty in using complete dentures. Several options have been used for implant-supported overdenture attachments. Among these, bar attachment system has greater retention and better maintainability than others. SFI-Bar$^{(R)}$ is prefabricated and can be adjustable at chairside. Therefore, laboratory procedures such as soldering and welding are unnecessary, which leads to fewer errors and lower costs. A 67-year-old female patient presented, complaining of mobility of lower anterior teeth with old denture. She had been wearing complete denture in the maxilla and removable partial denture in the mandible with severe bone loss. After extracting the teeth, two implants were placed in front of mental foramen, and SFI-Bar$^{(R)}$ was connected. A tube bar was seated to two adapters through large ball joints and fixation screws, connecting each implant. The length of the tube bar was adjusted according to inter-implant distance. Then, a female part was attached to the bar beneath the new denture. This clinical report describes two-implant-supported overdenture using the SFI-Bar$^{(R)}$ system in a mandibular edentulous patient.

• 복식
• /
• 제61권7호
• /
• pp.67-79
• /
• 2011

This study is to design a ball-jointed doll costume with historical research in clay female doll's costume from Hwangsung-dong tomb of the Silla Dynasty[新羅] in 7C. This clay female doll's costume was characterized by slim silhouette, long sleeves, no neckline, side slit, high waistline, and bun on the back neck of representative of the early era. According to literature of 7-8C and textile relics, it is presumed that she wore short Jeogori[短衣, Dan-eui] with long sleeves and two layered skirt, and Dan-ryeong(團領) could be added as attachment that is reflective of the time era. For making design costume, Ra[羅, silk gauze] was used for long Dan-ryeong, plain silk and brocade[錦, Geum] for Dan-eui and skirt as a special textile of this period. Waist dart and small snap were added to the costume of ball-jointed doll because of hardness and curvy shape of doll's body, without contradicting traditional value. For better use of this study and cost reduction purposes, development of production system for traditional doll costumes should be considered.

• 동력기계공학회지
• /
• 제17권5호
• /
• pp.78-85
• /
• 2013

A high thermal conductivity material, namely graphene is treated by planetary ball milling machine to transport the heat by increasing the temperature. Experiments were performed to assess the heat transfer enhancement benefits of coating the bottom wall of copper substrate with graphene. It is well known that the graphene is unable to disperse into base fluid without any treatment, which is due to the several reasons such as attachment of hydrophobic surface, agglomeration and impurity. To further improve the dispersibility and thermal characteristics, planetary ball milling approach is used to grind the raw samples at optimized condition. The results are examined by transmission electron microscopy, x-ray diffraction, Raman spectrometer, UV-spectrometer, thermal conductivity and thermal imager. Thermal conductivity measurements of structures are taken to support the explanation of heat transfer properties of different samples. As a result, it is found that the planetary ball milling approach is effective for improvement of both the dispersion and heat carriers of carbon based material. Indeed, the heat transfer of the ground graphene coated substrate was higher than that of the copper substrate with raw graphene.

• 구강회복응용과학지
• /
• 제25권4호
• /
• pp.375-390
• /
• 2009

하악 완전 무치악 환자에서 이공 사이에 2개의 임플란트를 식립한 후 4종류의 어태치먼트를 사용한 하악 오버덴쳐를 제작하여 유한요소 모델을 만들고 여기에 3가지 하중 조건을 가하여 유한요소 해석 프로그램인 ANSYS 10.0을 이용하여 어태치먼트 종류에 따른 임플란트 주위골과 보철물 및 임플란트와 골 사이 계면에 발생하는 최대 응력의 크기와 응력 분포양상을 분석하였다. 하악골체의 전체적인 골격구조에서 치아 부분은 오버덴쳐로 모델을 형성하였고 오버덴쳐와 하악골 사이에 2mm 두께의 점막을 삽입하였다. 임플란트 오버덴쳐의 유한요소 모델은 ball and socket, Locator, magnet, bar의 각각 4가지 형태를 제작하였다. 고정체의 식립 위치는 양측 이공 전방이고, 경계 조건 중 고정점은 하악각 부위와 모형의 최후방 절점들을 고정점으로 설정하였다. 하중조건은 오버덴쳐의 좌측 제 2소구치에서 제 2대구치 편측 부위에 170N의 하중을, 좌 우측 제 2소구치에서 제 2대구치 양측 부위에 170N의 하중을, $90^{\circ}$수직 방향, $45^{\circ}$경사, 그리고 $0^{\circ}$ 수평 방향으로 가하였다. 결과 분석시 모든 하중방향에서 응력의 크기는 bar에서 임플란트나 오버덴쳐에서 가장 크게 나타났으며, 계면에서의 응력은 모든 어태치먼트에서 비슷한 응력분포가 나타났다. Ball and socket, Locator, magnet에서는 유의성을 보이지 않았다. 응력의 분포도에서는 4종류의 어태치먼트 모두 임플란트 치경부에서 응력이 집중된 양상을 보였으며 bar타입에서는 bar의 중앙에 응력이 크게나타났다. 이상의 결과로 볼 때 어태치먼트의 종류에 따라 응력분포의 차이가 있었음을 확인할 수 있었다. 어태치먼트의 선정 시 응력집중을 완화시킬 수 있는 바람직한 설계와 선택이 필요하리라 사료된다.