• Korean Journal of Materials Research
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• v.15 no.4
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• pp.224-232
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• 2005

Dry sliding wear behavior of electro-pressure sintered Fe-Ni and Co-Fe-Ni compacts was investigated. Pin-on-disk wear tests were performed on the sintered Fe-Ni, Co-Fe-Ni disk specimens against alumina $(Al_2O_3)$ and silica $(SiO_2)$ ball counterparts at various loads ranging from 3N to 12N. A constant sliding speed of 0.1m/sec was employed. Wear rate was calculated by dividing the weight loss measured after the test by specific gravity and sliding distance. Worn surfaces and cross sections of them were examined by a scanning electron microscopy, and wear mechanism of the compacts was investigated. Wear characteristics of the compacts were discussed as a function of composition of the compacts. Relationship between the wear rate and mechancial properties of the compact was explored, and effects of the oxide layer that was formed on wearing surface of the compacts on the wear were also studied.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.66-71
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• 2016

Reducing the wafer breakage rate and sawing thinner wafers will decrease the cost of solar cells. This study was carried out in order to identify ways to achieve this goal. In this study, the cutting force characteristics using an ingot tilting-type diamond multi wire-sawing machine were analyzed. The cutting force was analyzed while varying the tilting angles and wire speed. The obtained data were analyzed by classifying the tangential cutting force and the normal cutting force. In this cutting force experiment, the difference between the forces was confirmed; it was found that it rises with increasing the tilting angles and decreases when the wire speed elevates. The resulting value can be utilized as basic data for the determination of an ideal cutting recipe.

• Journal of Powder Materials
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• v.11 no.6 s.47
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• pp.451-461
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• 2004

Dry sliding wear behavior of electro-pressure sintered Co-Fe and Co-Ni compacts was investigated. Pin-on-disk wear tests were performed on the sintered Co-Fe, Co-Ni disks against alumina $(Al_2O_3)$ and silica $(SiO_2)$ balls at various loads ranging from 3N to 12N. A constant sliding speed of 0.1m/sec was employed. Wear rate was calculated by dividing the weight loss of a specimen by the measured specific gravity and sliding dis-tance. Worn surfaces and cross-sections of the specimens were examined using an SEM and EDS to investigate wear mechanism of the compacts. The wear behavior of the compacts were discussed as a function of their com-position. Effects of mechancial properties of the compact as well as oxide layers formed on wearing surface on the wear were also discussed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.6
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• pp.225-229
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• 2011

Most of the silicon cutting methods using the multi-wire with the slurry injection have been used for wafers of the crystalline solar cell. But the productivity of slurry injection cutting type falls due to low cutting speeds. Also, the direct contact with the metal wire and silicon block increases the concentration of metallic impurities in the wafer's surface. In addition, the abrasive silicon carbide (SiC) generates pollutants. And production costs are rising because it does not re-use the worn wire. On the other hand, the productivity of the cutting method using the diamond coated wire is about 2 times faster than the slurry injection cutting type. Also, the continuous cutting using the used wire of low wear is possible. And this is a big advantage for reduced production costs. Therefore, the cutting method of the diamond coated wire is more efficient than the slurry injection cutting technique. In this study, each cutting type is analyzed using the surface characteristics of the solar wafer and will describe the effects of the manufacturing process of the solar cell. Finally, we will suggest improvement methods of the solar cell process for using the diamond cutting type wafer.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.54-67
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• 1998

The purposes of this study were to evaluate the efficiency of dentin cutting and root-end cavity preparation, and to determine the incidence of tooth crack when root-end retrograde cavity preparation was done with. ultrasonic diamond instruments. To evaluate the efficiency of dentin cutting, ultrasonic diamond and stainless steel instruments were applied to 20 exposed bovine dentin surfaces perpendicularly or parallely at the low, and medium power settings for 1 minute ($Miniendo^{TM}$, EIE, CA, U.S.A.). The resultant cavity depth was measured. To evaluate the efficiency of cavity preparation and to investigate the incidence of tooth crack, 165 mesiobuccal, distobuccal and palatal root-ends of extracted human maxillary first molars were resected by 3 mm perpendicularly to the long axis of tooth using a slow speed diamond saw after root canal preparation and filling. Retrocavities were prepared using a ultrasonic diamond instrument or a stainless steel one of the low- or medium power settings of 2 or 6. Time consumed and the number of strokes used for the cavity preparation were measured and the incidence of tooth cracks was evaluated under a stereomicroscope. The results were as follows: Both at the low and medium power settings, and both with perpendicularly- and parallely applied tips to dentin, diamond instruments showed higher dentin cutting efficiency than stainless steel ones did (p<0.01). When tips were applied to dentin perpendicularly, both diamond instrument and stainless steel one showed higher cutting efficiency with medium power setting than with low power one (p<0.01). Both at the low- and medium power settings, both diamond instrument and stainless steel one showed higher cutting efficiency when tips were applied perpendicularly to dentin surface than applied parallely (p<0.01). At the medium power setting, the number of stroke and time consumed were less with diamond instrument than with stainless steel one (p<0.05) for the retrograde cavity preparation. At the low power setting, diamond instrument induced less tooth cracks than stainless steel one did (p<0.01).

• Explosives and Blasting
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• v.18 no.3
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• pp.49-58
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• 2000

본 논문은 양면발파에 의한 채석기술에서 주로 양면발파 장약패턴 및 다이아몬드 와이어쏘절삭기술에 관한 내용을 중심으로, 현재 각 석재광산에서 시행하고 있는 채석기술과 연구소 에서 시행한 현장 시험발파 결과를 기술한 것이다. 첫째, DA석재광산에서는 제트버너를 이용하여 자유면을 형성하고, 일면발파법과 양면발파법의 작업시간을 비교한 결과 양면 발파할 때에 37%이상의 작업시간 절약효과가 있었으며, 인원은 36%이상의 감소효과가 있었다.둘째, DH석재광산에서는 다이아몬드 와이어쏘를 이용하여 자유면을 형성하고 양면발파 작 업시간과 타 광산에서 일반적으로 사용하고 있는 제트버너에 의한 양면발파 작업시간을 비교하였을 때에 21%이상의 절감효과가 있었고, 작업인원도 21%이상의 감소효과가 있었다. 다이아몬드 와이어쏘를 이용하여 양측면에 자유면을 형성하고 양면 발파하는 채석기술은 소음 및 분진에 의한 환경공해를 방지할 수 있었으며, 작업공정 및 경제성 면에서도 매우 유 리하나 실패시 다른 채석기술에 비해 모암의 손상으로 인한 경제적 손실이 커질 수 있다는 단점도 있으므로 정밀한 발파설계 및 기술이 필요하다.

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

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.569-569
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• 2003

I. Objectives The purpose of this study was to evaluate the effort of a modified luting procedure called "dual bonding technique" by compare micro-shear bond strength to different luting procedures of ceramics to dentin. II. Materials and Methods Eighty-four freshly extracted caries-and restoration-free human third molar were embedded in epoxy resin using acrylic ring. Flat superficial occlusal dentin surfaces were obtained, initially using a Low speed diamond saw and exposed detin surface was group with ＃600-grit SiC paper.(omitted)

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.609-609
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• 2003

I. Objectives The purpose of this study was to evaluate the effect of adhesive property on microtensile bond strength and to determine the failure mode. II. Materials and Methods Flat occlusal dentin surfaces were prepared using low-speed diamond saw. The dentin was etched with 37% phosphoric acid. The following adhesives were applied to the etched dentin according to manufacturer's directions；Scotchbond Multi-Purpose in group 1, Primer＆Bond NT in group 2, Scotchbond Multi-Purpose followed by Tetric-flow in group 3. After adhesive application, a cylinder of resin-based composite was built up the occlusal surface.(omitted)

• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.419-424
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• 2001

We intended to evaluate the Young's modulus of trabecular bone of a human distal femur by spherical Indentation test and CT images and to quantify relationships between the direction of load, density. and Young's modulus. The specimens were scanned at 1 mm intervals on CT scanner After scanning the bones were sectioned with diamond saw. producing 8mm cubes of trabecular bone. The tubes were mechanically tested in inferior-superior(IS), anterior-posterior(AP). and medial-lateral(ML) direction with custom-made device. After testing, the real apparent density of specimens were measured. The results of this study showed that the IS modulus was significant1y greater than both the AP and ML modulus and the AP modulus was also greater than ML modulus significantly(p〈0.01) A significant Power relationship between the apparent density and the modulus was also found.