• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.3
• /
• pp.507-514
• /
• 2024

In the semiconductor manufacturing line, continuous efforts are being made to reduce the cost of products produced, and the demand for this is accelerating in the chemical mechanical polishing(CMP) process, and a representative example of these cost reduction items is the 5-Zone Ring. After about 150 hours of use in the CMP process, the thickness of the ring decreases to less than 1 mm and must be replaced with a new product. Therefore, in this study, bonding dispensers and press machines with a dispensing amount error of 10g±0.8% or less and a pressure uniformity of ±1.8% or less were developed to reduce semiconductor manufacturing costs by repeatedly regenerating worn parts of the retainer ring, and to minimize environmental pollution caused by industrial waste treatment.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.463-464
• /
• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.443-444
• /
• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.11a
• /
• pp.527-528
• /
• 2010

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.4
• /
• pp.332-337
• /
• 2013

This paper presents a subsequent research work on the roller design of IRB(isolation roller bearing) seismic isolation device presented in Part 1 by focusing on heat treatment. The hardness and friction factor are very important factors of material and after-treatment process selection. Normally, roller bearing consists of roller and retainer. The roller gets high pressure constantly, while the retainer gets tensile and compressive stress. Therefore, sensitive material selection and heat treatment of each part is quite important. In this experimental evaluation, carbon steel, chrome special steel and others are employed and their characteristics after heat treatment are identified. Each material is prepared by refining high frequency heat treatment. The friction factor and static load capacity of manufactured material are experimentally identified and destructive test of material is processed. Optimal material and heat treatment conditions for IRB roller bearing are determined based on experiment results.

• Journal of the Korean Society for Library and Information Science
• /
• v.20
• /
• pp.17-33
• /
• 1991

This articles aims to analyze HOSEONGKONGSINLOK awarded to Kim Yang-bo, a eunuch, having major roles to take refuge the king Seon-jo when the Japanese invader rushed into Seoul in the time of Hideyoshi's Invasion of Korea in 1592. At that time, all meritorious retainer was to be rewarded equally by a given rules of the stipends and the gifts. But for the eunuch, differently from others, the portrait was not made to be handed down as a model. Instead one more clothes was given. This suggests that there were some differenciation of the class and the job in the evaluation of the merits. From this we can see that there might be some problems in the selection of the meritorious retainer, resulting in unfair awarding, and needing to be reevaluation from the historian. Even though somewhat worn out, this material has very important value as a historical source in terms of following viewpoint: 1) it contains all the name of the meritorious retainers at that time. 2) it suggests the social situation and affairs at that time more precisely. 3) it reveals the facts even some facts in the authentic records can be corrected.

• The Journal of Korean Academy of Prosthodontics
• /
• v.41 no.1
• /
• pp.81-88
• /
• 2003

Resin-bonded bridge has been an alternative to conventional bridge, since resin-bonded bridge has many attractive advantages such as minimal tooth preparation, short chair time and low cost over conventional bridge. Unfortunately, however, it was reported that resin-bonded bridge showed high failure rate from debonding of retainer in spite of consecutive advances in preparation and materials. And it was shown that multiple abutments were more likely to fail. The majority of debonding failure was considered due to the mobility of the abutment during function. In this view, recently, modification in resin-bonded bridge design was tried. Single retainer, single pontic. 2-unit cantilevered resin-bonded bridge was applied to clinical performance and was shown as retentive or more retentive than fixed-fixed type resin-bonded bridge. This was consistent with the results of studies in 2-unit cantilevered resin-bonded bridges made with all ceramic, In-ceram. The purpose of this article was to overview principles of design and to analyze clinical results of 2-unit cantilevered resin-bonded bridge in comparison with the reports of fixed-fixed resin-bonded bridge.

• The Journal of Korean Academy of Prosthodontics
• /
• v.39 no.5
• /
• pp.547-555
• /
• 2001

This study was performed tn investigate the effects of impression method and design of the retainer on the stress of abutment tooth in distal extension RPD. Three different types of direct retainer such as Akers clasp, RPI clasp, and wrought wire clasp were designed. Stress on the abutment tooth was measured and analyzed with strain gauge method. Impressions were anatomic impression technique and functional impression technique. The following conclusions were drawn from this study. 1. The stress at the abutment tooth on all RPD was decreased in functional impression except RPI clasp retained RPD. 2 The stress at the abutment tooth on RPI clasp retained RPD was the most smallest in anatomic Impression. 3. While load is increase the stress at the abutment tooth was increased, but the change of stress at the buccal side of abutment tooth was not too much in functional impression.

• Restorative Dentistry and Endodontics
• /
• v.45 no.2
• /
• pp.15.1-15.7
• /
• 2020

This clinical report describes designing and fabricating a single-retainer resin-bonded fixed dental prosthesis with a chair-side computer-aided design/computer-aided manufacturing system. The whole procedure, from tooth extraction to final placement of the prosthesis, was completed in one day, and a single clinic visit. No clinical complications were found at the 2-year follow-up after placement of the restoration, and satisfactory functional and esthetic results were achieved.

• The Journal of Korean Academy of Prosthodontics
• /
• v.30 no.1
• /
• pp.25-42
• /
• 1992

The purpose of this study was to analyze the magnitude and distribution of stress using a photoelastic model from a unilateral distal extention removable partial dentures with five kinds of the direct retainers, that is, the bilaterally designed bar clasp of the cross-arch lingual bar and the unilaterally designed bar clasp, circumferential clasp, mini-Dalbo attachment, and telescope retainer. A photoelastic model for mandible was made of the epoxy resin(PL-1) and hardner (PLH-1) with the acrylic resin teeth used and was coated with plastic cement-1 at the lingual surface of the model, and then five kinds of removable partial dentures were set, A unilateral vertical load of about 16Kg was applied on the first molar and the stress pattern of the photoelastic model under each condition was analyzed by the reflective circular polariscope. The following results were obtained: 1. The conventional removable partial denture with the bilaterally cross arch lingual bar produced the most favorable stress distribution on the residual ridge and supporting structure of abutment teeth than the unilaterally designed removable partial dentures. 2. The unilaterally designed removable partial denture with the bar clasp produced the stress distribution on the residual ridge, except sligtly higher stress concentration on the supporting structure of the abutment teeth, similar to the conventional removable partial denture with the bilaterally designed cross arch lingual bar. 3. On the unilaterally designed removable partial dentures, the bar clasp produced greater stress distribution on the residual ridge and supporting structure of the abutment teeth than the circumferential clasp. 4. On the unilaterally designed removable partial dentures, the mimi-Dalbo attachment produced relatively higher stress concentration on the residual ridge, but produced lesser stress concentration on the supporting structure of the abutment teeth than the other direct retainers. 5. On the unilaterally designed removable partial dentures, the telescope retainer produced uniform stress distribution on the residual ridge, but produced higher stress concentration at the root apex of the terminal abutment tooth than the other direct retainers. 6. On the unilaterally designed removable partial dentures the circumferential clasp and telescope retainer produced slightly higher stress concentration on the residual ridge and supporting structure of the abutment teeth than the bar clasp and mini- Dalbo attachment.