• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.46-49
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• 2003

Chemical mechanical polishing (CMP) is an essential dielectric planarization in multilayer microelectronic device fabrication. In the CMP process it is necessary to minimize the extent of surface defect formation while maintaining good planarity and optimal material removal rates. The polishing mechanism of W-CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. Thus, it is important to understand the effect of oxidizer on W passivation layer, in order to obtain higher removal rate (RR) and very low non-uniformity (NU%) during W-CMP process. In this paper, we compared the effects of oxidizer or W-CMP process with three different kind of oxidizers with 5% hydrogen peroxide such as $Fe(NO_3)_3$, $H_2O_2$, and $KIO_3$. The difference in removal rate and roughness of W in stable and unstable slurries are believed to caused by modification in the mechanical behavior of $Al_3O_3$ particles in presence of surfactant stabilizing the slurry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.45-48
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• 2003

The polishing mechanism of W-CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. Thus, it is important to understand the effect of oxidizer on tungsten passivation layer in order to obtain higher removal rate (RR) and very low non-uniformity (NU%) during W-CMP process. In this paper, we investigated the effects of oxidizer on W-CMP process with three different kinds of oxidizers, such as $H_2O_2$, $Fe(NO_3)_3$, and $KIO_3$. In order to compare the removal rate and non-uniformity of three oxidizers, we used alumina-based slurry of pH 4. According to the CMP tests, three oxidizers showed different removal mechanism on tungsten surface. Also, the microstructures of surface layer by AFM image were greatly influenced by the slurry chemical, composition of oxidizers. The difference in removal rate and roughness of tungsten surface are believed to caused by modification in the mechanical behavior of $Al_2O_3$ abrasive particles in CMP slurry. Our stabilized slurries can be used a guideline and promising method for improved W-CMP process.

• Structural Engineering and Mechanics
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• v.84 no.1
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• pp.17-33
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• 2022

An experimental study is carried out to investigate the performance of the cutting tool regarding the insert wear, surface roughness, cutting forces, cutting power and material removal rate of three coated carbides GC2015 (TiCN-Al₂O₃-TiN), GC4215 (Al₂O₃-Ti(C,N)) and GC1015 (TiN) during the dry turning of AISI4140 steel. For this purpose, a Taguchi design (L₉) was adopted for the planning of the experiments, the effects of cutting parameters on the surface roughness (R_a), tangential cutting force (F_z), the cutting power (P_c) and the material removal rate (MRR) were studied using analysis of variance (ANOVA), the response surface methodology (RSM) was used for mathematical modeling, with which linear mathematical models were developed for forecasting of R_a, F_z, P_c and MRR as a function of cutting parameters (V_c, f, and a_p). Then, Multi-Objective Ant Lion Optimizer (MOALO) has been implemented for multi-objective optimization which allows manufacturers to enhance the production performances of the machined parts. Furthermore, in order to characterize and quantify the flank wear of the tested tools, some machining experiments were performed for 5 minutes of turning under a depth of 0.5 mm, a feed rate of 0.08 mm/rev, and a cutting speed of 350 m/min. The wear results led to a ratio (V_B-GC4215/V_B-GC2015) of 2.03 and (V_B-GC1015/V_B-GC2015) of 4.43, thus demonstrating the efficiency of the cutting insert GC2015. Moreover, SEM analysis shows the main wear mechanisms represented by abrasion, adhesion and chipping.

• Journal of Veterinary Clinics
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• v.13 no.2
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• pp.144-148
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• 1996

The effectiveness of sodium carboxymethylcellulose (SCMC) and deztran in the prevention of adhesion formation on the uterus and embryo collection in rabbits was elucidated. Following induction of adhesion on uterus and uterine horns by abrasion and retrograde flushing of embryos in gonadotropins primed rabbits, the solutions of saline (for control), 1% SCMC, 10% dextran and a synthetic solution of 1% SCNC and 10% dextran in saline were infused in the abdominal cavity at the dose of 5 ml/kg of body weight. The average percentage of adhesion was 11.1, 28.6, 41.7 and 73.3% in the rabbits infused with the synthetic, 1% SCMC, 10% dextran and saline solutions, respectively. The synthetic solution was more effective than other solutions in the rabbits. The average number and recovery rate of embryos were significantly (P<0.01) higher in the synthetic solution group than 1% SCMC, 10% dextran or saline solution groups. Among the collected embryos in the groups, the distribution of the normal embryos was higher in the synthetic solution group (99%) and the 10% dextran solution group (95.7%) than the 1% SCMC solution group (78.4%) and saline (66.2%). Theretore, a synthetic solution which is combined with 1% SCMC and 10% deztran in saline can be effectively used for the prevention of adhesion formation after uterine surgery and embryo collection.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.78-83
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• 2010

On the paved track, the ballast is used as aggregate for the filling layer using the pre-packed concrete technique. The most important condition of aggregate is adhesive strength with mortar. To satisfy this condition, surface of aggregate should be cleaned by water or others. In a paved-track method to be introduced domestically, an environment-friendly dry-washing technology which will replace the water-washing method has been developed. A dry-washing method was designed to blast the crushed weight material with a diameter of 0.3~0.5mm at high pressure to peel the surface of the aggregate. The study was intended to enhance the washing efficiency of dry-blasting technology and to that end, the tests including blasting material, content of fine aggregate depending on time elapsed, content of chloride, LA abrasion rate and compressive strength were conducted to recommend the efficient washing material and the process.

• Tribology and Lubricants
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• v.30 no.4
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• pp.199-204
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• 2014

Various heat-treated and surface coating methods are used to mitigate abrasion in sliding machine parts. The most cost effective of these methods involves hard coatings such as diamond-like carbon (DLC). DLC has various advantages, including a high level of hardness, low coefficient of friction, and low wear rate. In practice, a supporting layer is generally inserted between the DLC layer and the steel substrate to improve the load carrying capacity. In this study, an indentation and sliding contact problem involving a small, hard, spherical particle and a DLC-coated steel surface is modeled and analyzed using a nonlinear finite element code, MARC, to investigate the influence of the supporting layer thickness on the coating characteristics and the related coating failure mechanisms. The results show that the amount of plastic deformation and the maximum principal stress decrease with an increase in the supporting layer thickness. However, the probability of the high tensile stress within the coating layer causing a crack is greatly increased. Therefore, in the case of DLC coating with a supporting layer, fatigue wear can be another important cause of coating layer failure, together with the generally well-known abrasive wear.

• Korean Journal of Health Education and Promotion
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• v.2 no.1
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• pp.122-132
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• 1984

Aiming to obtain knowledge and information on tetanus occurrence in Korea, an analystical survey was carried out for registered and admitted patients in four large hospitals in Korea during January 1, 1974 through December 31, 1983. Tile results showed as follows: 1. 175 among total 453 tetanus patients died in the hospitals, therefore fatal rate showed as 24.1%. However, the discharged patients against doctors' advices were not included in these died cases. 2. Sex ratio of admitted tetanus patients between male and felame was shown as 3 : 1. 3. Home delivery in neonate tetanus and laceration and abrasion in non-neonate tetanus were observed as the most dominant cause of death respectively and the wound of foot lead the most dominant cause of death in the latter. 4. Clinical features of the tetanus patients on admission showed the following order in the frequency: sucking and disphagia failure(50.8%), convulsion (53.8%), trismus (50.8%). 5. The tetanus patients were terminated with mainly respiratory ani cardiac failure. 6. In the treatment for tetanus patients, airway (58.3%), intubation (45.3%) and tracheostomy(9.7%) were applied respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2387-2396
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• 2000

Wear and operation characteristics of Nylon and Acetal pinion against steel gear were studied to gain a better understanding of their tribological and mechanical behavior. Tests were conducted with power circulating gear test rig under unlubricated conditions. Specific wear rates were measured as a function of applied load and total revolution. The worn tooth surfaces were examined with a profile projector and camera. Nylon pinion showed lower specific wear rates than Acetal pinion, but it revealed breakage at high load. Principal wear depths were developed at tooth tip and below the pitch line of pinion. Life estimation for the Nylon pinion was made by taking into account steel gear equivalent Hertz stress and average sliding velocity. The dominant wear mechanisms were adhesion and abrasion.

• Journal of Trauma and Injury
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• v.26 no.3
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• pp.214-217
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• 2013

Tetanus is a neurologic disorder caused by a tetanospasmin released from Clostridium tetani and usually occurs as a result of a dirty open wound or abrasion. Post traumatic tetanus is a life threatening disease and has a mortality rate of 15~39%. Because of a nationwide active immunization program, tetanus is a rare disease in Korea. Thus, many physicians have little experience with its diagnosis and management, and misdiagnosis and therapeutic delay may have catastrophic consequences. We report a case of tetanus that developed in a patient who had been diagnosed with a traumatic rectal rupture.

• Resources Recycling
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• v.16 no.5
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• pp.13-18
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• 2007

The recycled aggregates produced from waste concrete by crushing and granularity adjusting processes only can't be used for structural aggregates because they display low density and high abrasion rate by including lots of mortar and cement paste. However, the recycled aggregates include a lot of aggregates for concrete. Using the heavy medium separation method that is one of the specific gravity separation methods, about 45% of the waste concrete could be converted to the recycled aggregates.