• The Journal of Advanced Prosthodontics
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• v.13 no.3
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• pp.180-190
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• 2021

Purpose. This study aimed to assess the influence of various micromechanical surface conditioning (MSC) strategies with or without coupling agent (silane) application on the micro-shear bond strength (µSBS) of resin- matrix ceramics (RMCs). Materials and Methods. GC Cerasmart (GC), Lava Ultimate (LU), Vita Enamic (VE), Voco Grandio (VG), and Brilliant Crios (BC) were cut into 1.0-mm-thick slices (n = 32 per RMC) and separated into four groups according to the MSC strategy applied: control-no conditioning (C), air-borne particle abrasion with aluminum oxide particles (APA), 2W- and 3W-Er,Cr:YSGG group coding is missing. The specimens in each group were further separated into silane-applied and silane-free subgroups. Each specimen received two resin cement microtubules (n = 8 per subgroup). A shear force was applied to the adhesive interface through a universal test machine and µSBS values were measured. Data were statistically analyzed by using 3-way ANOVA and Tukey HSD test. Failure patterns were scrutinized under stereomicroscope. Results. RMC material type, MSC strategy, and silanization influenced the µSBS values (P<.05). In comparison to the control group, µSBS values increased after all other MSC strategies (P<.05) while the differences among these strategies were insignificant (P>.05). For control and APA, there were insignificant differences between RMCs (P>.05). The silanization decreased µSBS values of RMCs except for VE. Considerable declines were observed in GC and BC (P<.05). Conclusion. MSC strategies can enhance bond strength values at the RMC - cement interface. However, the choice of MSC strategy is dependent on RMC material type and each RMC can require a dedicated way of conditioning.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.193-202
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• 2016

Purpose: This study was performed in order to assess the effect of the surface treatment methods and the use of bonding agent on the shear bond strength (SBS) between the aged CAD-CAM (computer aided design-computer aided manufacturing) hybrid materials and added composite resin. Materials and methods: LAVA Ultimate (LU) and VITA ENAMIC (VE) specimens were age treated by submerging in a $37^{\circ}C$ water bath filled with artificial saliva (Xerova solution) for 30 days. The surface was ground with #220 SiC paper then the specimens were divided into 9 groups according to the combination of the surface treatment (no treatment, grinding, air abrasion with aluminum oxide, HF acid) and bonding agents (no bonding, Adper Single Bond 2, Single Bond Universal). Each group had 10 specimens. Specimens were repaired (added) using composite resin (Filtek Z250), then all the specimens were stored for 7 days in room temperature distilled water. SBS was measured and the fractured surfaces were observed with a scanning electron microscope (SEM). One-way ANOVA and Scheffe test were used for statistical analysis (${\alpha}=.05$). Results: Mostly groups with bonding agent treatment showed higher SBS than groups without bonding agent. Among the groups without bonding agent the groups with aluminum oxide treatment showed higher SBS. However there was no significant difference between groups except two subgroups within LU group, which revealed a significant increase of SBS when Single Bond Universal was used on the ground LU specimen. Conclusion: The use of bonding agent when repairing an aged LAVA Ultimate restoration is recommended.

• Journal of the Korean Society of Clothing and Textiles
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• v.11 no.1
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• pp.1-10
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• 1987

We selected four kinds of cotton velvet and chafed before and after cleaning, then in accordance with abrasion times we measured of pile exclusion rate and examined the relationship of the pile exclusion rate, its thickness and the air permeability. An experimental study was carried out the pile weave construction, the density, the yarn to yarn, the shrinkage, and the pile substantiality. The results were as follows: 1. In accordance with increments of shrinkage phenomenon of pile fabric for cleaning process, pile exclusion rate was decreased. 2. The ground weave of pile fabric and the yarn to yarn of warp and weft direction were affected by the pile exclusion. 3. It is linear of pile substantiality of pile fabric and pile fastness. 4. In estimation of pile exclusion rate, it is proper to make use of air permeability and measuring value of thickness.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.22-27
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• 2002

The existing compressor steel seal used in automotive air-conditioner has the problem of oil leakage and the deterioration in shielding performance, due to the abrasion and the corrosion of the material. A new type of polymer resin seal is studied in the research. The polymer resin seal has the characteristics of high anti-abrasiveness and anti-corrosiveness, which can overcome the deflects of the steel seal. In addition, the seal needs lower manufacturing cost and is appropriate to mass production, because it is made by the injection molding method requiring no mechanical processing. The profile generation program for seal mold has been developed using the gradient method, and the molding characteristics of the seal have analyzed through the flow analysis and the warpage analysis. The program has been verified by comparing the analysis results with the measured data of the test product. The research might be said to provide the basic method to produce the polymer resin seals with various types and dimensions.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.5
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• pp.81-87
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• 2002

The existing compressor steel seal used in automotive air-conditioner has the problem of oil leakage and deterioration in shielding performance, due to the abrasion and corrosion of the material. A new type of polymer resin seal studied in this research has the characteristics of high anti-abrasiveness and anti-corrosiveness, which can oversome the defects of the steel seal. In addition, the seal needs lower manufacturing cost and is appropriate to mass production, because it is made by the injection molding method requiring no mechanical processing. The profile generation program for seal mold has been developed using the gradient method, and the molding characteristics of the seal have analyzed through the flow analysis and the warpage analysis. The program has been verified by comparing the analysis results with the measured data of the test product. The research might be said to provide the basic method to produce the polymer resin seals with various types and dimensions.

• Journal of the Korean Home Economics Association
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• v.19 no.2
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• pp.143-149
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• 1981

Consumer consider the purpose for which they plan to use clothes when they purchase it, and the socks in textile products is evaluated in the same way. serviceability is judged by the extent to which the socks will be useful for its intended purpose. It should retain its original shape and size, good air permeability, good absorbency, good abrasion resistance, high fastness etc. Owing to importance of serviceability in socks, in this paper, these end-use requirement characteristics were tested. The results obtained were as follows: 1. Blend ratios were different between the indicated fiber contents on labels and the testing ones. 2. Air permeability was higher in the samples which contain less stitch density, and hydroscopicity was higher in those which contain natural fibers such as cotton and wool. 3. Shrinkage depended on the blend ratios of cotton and wool, and elastic recovery was better in the course direction than in the wale direction. 4. Pilling was conspicuous in the synthetic fibers such as polyester and nylon, and fastness of laundering and perspiration was higher in the fading grade than in the staining grade.

• Journal of Chest Surgery
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• v.31 no.11
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• pp.1070-1075
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• 1998

Background: With the advent of thoracoscopy, there has been increasing interest in less invasive surgical bullectomy and pleurodesis. The recurrence rate, however, has been reported higher in surgery with thoracoscopy than with open thoracotomy and it is thought to be caused by inappropriate mechanical pleurodesis during thoracoscopic surgery. Materials and methods: We compared the short-term recurrence rates according to the intensities of pleural abrasion in 62 patients who underwent VATS for treatment of spontaneous pneumothorax from April 1996 to August 1997. The patients were divided into 2 groups: group A(n=32) included patients who received relatively weak pleural abrasion using Endo-forcep instrument for grasping the gauze, and group B(n=30) received strong pleural abrasion using conventional instrument wrapped tightly with gauze. Each intensity of pleural abrasion allowed petechia on the parietal pleura in group A, and some tearing and bleeding in group B. Results: Indications for operation, sex distribution, and age were comparable in both groups. There were no differences in chest tube indwelling time(3.78±3.35 vs 3.80±2.49 days), hospital stay(4.72±1.87 vs 4.67±2.20 days), and the amount and duration of analgesics required postoperatively. Persistent air-leak more than 7 days after surgery occurred in 4/32(12.5%) and 2/30(6.7%) in group A and B, respectively. No bleeding-related complication occured. Pneumothorax recurred 12.5%(4/32) and 0%(0/30) of patients at a mean follow-up of 9.7 and 9.6 months in group A and B, respectively, and it was statistically significant(p<0.05). Conclusions: Proper intensity of pleural abrasion is very important factor to reduce recurrence after VATS for spontaneous pneumothorax. During short-term follow-upafter surgery, we could achieve excellent result in reducing recurrence rate with VATS and strong pleural abrasion which is comparable to thoracotomy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1766-1769
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• 2005

Air-operated valve(AOV) is one of principal valves that are using to control fluid flow in nuclear power plants. AOV is suffered from damage and malfunction by the abrasion, corrosion and vibration of valve parts under the long time operation. This mechanical trouble and malfunction of valve is critical for the safety of power plant. So a periodic diagnosis for safety of power plants is inevitable to guarantee the safety of the power plant. But depending on the type of the actuator and valve body, various types of AOV exist. In this study, It is developed the diagnostic system that users of power plants are easy to handle in this paper.

• Journal of Periodontal and Implant Science
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• v.30 no.4
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• pp.821-836
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• 2000

The Peri-implantitis causes inflammation of periodontal tissue and bone loss. It contaminates surface of implants. Therefore, guided bone regeneration has been used for the treatment of this disease. For the reosseointegration of the exposed surface, various mechanical and chemical methods have been used for cleaning and detoxication of implant surface. Among these methods, air-powder abrasive and oversaturated citrate are known to be most effective. However, these treatments may deform implant surface. In this research, changes of surface roughness they were examined. 10 experimental machined titanium cylinder models were fabricated to be used for control groups. Each of them was air powder abraded for 1 minute and they were named group 1. And then, group 1 were burnished with cotton pellets soaked with citrate for 30 seconds(Group 2), 1 minute(Group 3), 3 minutes(Group 4), and 5 minutes(Group 5) burnishing were applied for grouping respectively. Each group were examined with SPM, and their surface roughness were measured and analyzed. 1. Surface roughness of titanium decreased when it was air-powder abraded for 1 minute. It was statistically significant. 2. When Air-powder abraded titanium were treated with citrate for 3 minutes, Their surface roughness was the lowest. Titanium treated for 1 minute was the second lowest and 30 seconds was the third and titanium burnished for 5 minutes was the highest. 3. Surface roughness of titanium which was treated with citrate was decreased till 3 minutes, which was statistically significant. There was no statistical significance from 30 seconds to 1 minute and from 1 minute to 3 minutes, and there was statistical significance from 30 seconds to 3 minutes. 4. Oxide layer was formed when titanium is exposed to air, and it was removed when air-powder abraded. It was made when treated with citrate. It is thought that citrate treatment is necessary after the air-powder abrasion, and 1 minute is clinically and qualitatively adequate for burnishing time of citrate.

• Korean Journal of Materials Research
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• v.7 no.4
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• pp.310-316
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• 1997

The effects of carbide and matrix structures on the abrasion wear resistance of multi-component white cast irons with 3.0 mass%C have been studied in this paper. Four different heats were poured in order to obtain the specimens with different combinations of the carbide structures: a basic iron(3.0 mass%C-5.0 mass%Cr-5.0 mass%V-5.0 mass% Mo-12.5mass%W)for M$_{6}$C and M$_{7}$C$_{3}$ carbides, and a Cr free iron(3.0 mass%C-5.0 mass%V-2.5mass%Mo-12.5 mass%W) for MC and M6C carbides. A conventional high Cr free free iron(3.0 mass%C-5.0 mass%V-2.5 mass%Mo-12.5 mass%W) for MC and M6C carbides. A conventional high Cr white cast iron was also poured to compare its wear resistance with those of the multi-component white cast irons. In the as-cast condition, the range of abrasive wear rate(Rw=mg/min) was from 4.15 to 5.98 . The lowest Rw, which means the highest wear resistance, was obtained in the basic iron with nodular MC, lamellar M$_{2}$C and cellular M$_{7}$C$_{3}$ carbides. On the other hand, the Rw of the high Cr white cast iron ranked between the basic iron and the Mo and W free iron. In each alloy, the Rw of air hardened or tempered specimen was lower than that of the as-cast one because of the change of matrix structures by the heat treatments. The Rw of the hear treated speci-mens increased in the order Mo and W free iron, basic iron, Cr free iron, high Cr iron, and V free iron.n.n.n.