• Restorative Dentistry and Endodontics
• /
• v.21 no.1
• /
• pp.311-320
• /
• 1996

If root and resection is done during surgical endodontic treatment, newly exposed dentinal tubules form pathways between the canal and the peripheral tissue. Nd : YAG laser was used to block this phenomenon, and its effect was studied with dye penetration and SEM techniques. 40 intact single rooted teeth were divided into 4 groups(10 each) : control group and test groups, in which retrograde cavity surface, cutting surface, retrograde cavity surface & cutting surface were treated with laser(1 watt 15pps) and finally retrograde filling with IRM was conducted. After that, they were stained with 2 % methylene blue, sectioned and evaluated by the maximum infiltration depth. And to observe surface change, they were prepared for SEM. The results were as follows ; 1. All experimental groups showed microleakage with variation in amount. 2. The 2nd group which treated both the retrograde cavity and cutting surface showed significantly less microleakage than the other groups(p<0.05). There was no significant difference between groups treated on one side only. 3. As a result of SEM observation of dentin surface, obstruction of dentinal tubules with marble shaped granules, which were different from normal dentin could be seen. Cracks could be seen also. 4. In summary of this experiment, it is thought that effort to obstruct the exposed dentinal tubules as well as retrograde cavity after root end resection is needed.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.4
• /
• pp.68-75
• /
• 2005

This paper presents a new method for the optimization of feed rate in sculptured surface machining. A NC verification model based on Z-map was utilized to obtain chip load according to feed per tooth. This optimization method can regenerate a new NC program with respect to the commanded cutting conditions and the NC program that was generated from CAM system. The regenerated NC program has not only the same data of the ex-NC program but also the updated feed rate in every block. The new NC data can reduce the cutting time and produce precision products with almost even chip load to the feed per tooth. This method can also reduce tool chipping and make constant tool wear.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.801-805
• /
• 2000

This paper presents a new method of tool path optimization. A NC verification model based Z-map was utilized to obtain chip load in feed per tooth. This developed software can regenerate a NC program from cutting condition and the NC program that was generated in CAM. The regenerated NC program has not only all same data of the ex-NC program but also the new feed rates in every block. The new NC data can reduce the cutting time and manufacture precision dies with the same chip load in feed per tooth. This method can also prevent tool chipping and make constant tool wear. This paper considered the effects of acceleration and deceleration in feed rate change.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.24 no.2
• /
• pp.238-243
• /
• 2015

Recently, the use of assembled-type drills as environmentally friendly products has expanded because the shanks of drills can be reused by replacing the tip when the tools are worn or cut. In addition to their precision and endurable stiffness with respect to the cutting force, assembled-type drills need no stricture because of thermal deformation, which makes replacement easily. In this study, we developed novel assembled-type drills and compared their characteristics, such as the precision, stiffness, and thermal deformation, with those of conventional drills. The new drills exhibited a precision over IT 8 class and no changes in dimensions due to thermal deformation, such that we can change the assembly easily with durability.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.87-96
• /
• 2010

PAP method is a combined measures which consist a anchored retaining wall method with permanent ground anchors and vertical precast concrete panels, step by step on the slope surface. And soil is back filled between slope and vertical precast panels. Therefore, this method is more effective than any other ground anchor reinforcing methods of slope stability, for example cross type concrete block ground anchor or buttress concrete block ground anchor method. Because of increasing effective anchor force and green tree planting.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2005.10a
• /
• pp.404-409
• /
• 2005

The reinforced concrete blocks for reinforced earth layer are combined with soil structures consisted of facing unit, reinforcing materials and soil. Those environmentally friendly facing units of reinforced concrete blocks are made of mine waste and tailing and that will be played a role of the effects of recycling use of wasted resources. The block are consisted of three types as curved or straight in order to control topography. The systems are also not limited to wall hight so that they are effectively used for protecting the slope of banking and cutting of earth works. The reinforced concrete blocks developed this time will be effectively applied for not only retaining wall, road, park, golf course, public office building constructions but also protecting of slope stabilization projects.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.5 no.4
• /
• pp.189-197
• /
• 2009

This paper suggests the system for searching and application is to be in combination between existing hair art area and Image/Video processing area. This proposed system usually saves various hair types into a database, then, users send images of their face over the internet by using WebCam. Finally, they can find the hair types for users. Hair cutting is technology that form draft to make hair style. Man cut must decide how in image of sinciput, image of side bean curd, after lower image must operate. Silhouette is produced as is different by change of this three places. Customer increases in the beauty salon and beauty salon chain being changed, research about beauty art is necessary point of time. In this treatise, our country of when swim and operate haircut about problem that happen sample survey and analysis.

• Proceedings of the KACD Conference
• /
• 2003.11a
• /
• pp.579-579
• /
• 2003

I. Objectives The aim of this study was to evaluate and compare the effectiveness of sealer placement in simulated root canal extensions using the K file, ultrasonic file, lentulo spiral and EZ-Fill. II. Materials and Methods Forty resin blocks were attained from cutting Endo-training Bloc with diamond saw. In each parallelepiped block, the simulated root canal was made with ＃20, 08taper GT file. After each block was longitudinally split into two halves using mallet and chisel, a standardized groove of 4mm in length, located 2mmapart from the root apex, was prepared on one wall of two halves using the custom-made knife to simulate the canal extensions with various irregularities.(omitted)

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.23 no.5
• /
• pp.681-691
• /
• 1986

To represent the relations of the data dependency and resource conflict among micro-operations(MOP's) in the compaction process of microprograms, we propose a DDM (data dependent matrix) representation method instead of the DAG (conventional directed acyclic graph). Also, we propose a global compaction algorithm of microprograms to prevent a kind of block copying by cutting the trace at a junction block. The DDM method and compaction algoristhm have been applied to the Lah's example. The results shows that the proposed algorithm is more efficient than the conventional algorithms in reducing in reducing the total execution time and control memory space.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1991.04a
• /
• pp.243-250
• /
• 1991

This paper concerns the development of NC programming system TIG (Turning with Interactive Graphics) with interactive graphics for turning operation. The system cosists of the processor, the post-processor and the system-user interface. Different from previous segment contour based NC graphic programming systems, the frliability and efficiencyof programming is realized by using Boolean operation with block unit based ICONs for the geometry definition. The tool motion can be also displayed on the screen together with the part contour. The system calculate automatically the number of passes based on the user specified cutting conditions.