• Korean Journal of Dental Materials
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• v.43 no.1
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• pp.17-28
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• 2016

The aim of this study was to evaluate the changes in dentinal permeability after application of dentin desensitizer on exposed dentin immediately after ultrasonic scaling to teeth with non-carious cervical lesions. Thirty caries-free extracted molars were fixed to slide glasses after horizontally being sectioned at 5 mm below the cemento- enamel junction (CEJ). The prepared specimen was connected to a fluid flow measuring device (nano-Flow), and a V-shaped cavity was formed at the CEJ to imitate the non-carious cervical lesion. After no fluid leakage was confirmed in the connected system with specimen, tooth surface was treated ultrasonic cleaning with piezoelectric ultrasonic scalers until dentinal tubules were exposed. And 6 different desensitizers were applied on exposed dentin. Real-time measurements of dentinal fluid flow were performed during ultrasonic scaling and application of dentin desensitizer. To evaluate the occlusion of exposed dentinal tubules, tooth surface was examined by SEM. Following results were observed. After ultrasonic scaling, more dentinal tubules were exposed on the tooth with non-carious cervical lesions compared to tooth without lesions. The rate of fluid flow measured with nano-Flow system had correlation with the degree of dentin occlusion observed with SEM after application of desensitizers on exposed dentin. Desensitizers with glutaraldehyde and HEMA did not decrease the rate of fluid flow and did not show dentin occlusion. Desensitizers with oxalate showed the limited effects on the rate of fluid flow and dentinal tubule occlusion. Desensitizer with resin monomer showed the significant effect on the rate of fluid flow and dentin occlusion.

• The Korean Journal of Malacology
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• v.26 no.3
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• pp.245-254
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• 2010

For the studies of germ cell development and maturation in the ovary, the gametogenic cycle and the number of spawning seasons per year in female Ruditapes philippinarum were investigated by quantitative statistical analysis using an Image Analyzer System. Compared with the results by qualitative and quantitative analyses, monthly variations in female gonad indice by qualitative histological analysis showed a pattern similar to that of the female gametogenic cycle calculated by quantitative statistical analysis. The number of spawning seasons occurred once per year, from June to October. In quantitative statistical analysis using an image analyzer system, monthly changes in the portions (%) of the ovary area to total tissue areas in females increased in March and reached a maximum in May, and then showed a rapid decrease from June to October when spawning occurred. And also monthly changes in portions (%) of follicle areas to the ovary area and in portions of oocyte areas to ovarian tissue areas in females began to increase in March and reached a maximum in May, and then. rapidly dropped from June to October when spawnig occurred. From these data, it is apparent that the number of spawning seasons occurred once per year, from June to October. Monthly changes in the number of the oocyte per $mm^2$ and in mean diameter of the oocyte in captured image which were calculated for each female slide showed a maximum in May and reached the minimum from December to February. Therefore, female R. philippinarum showed a unimodal gametogenic cycle during the year.

• The Journal of Advanced Prosthodontics
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• v.13 no.5
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• pp.292-303
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• 2021

PURPOSE. The aim of this in vitro study was to evaluate the effect of silane and universal adhesive applications on the micro-shear bond strength (µSBS) of different resin-matrix ceramics (RMCs). MATERIALS AND METHODS. A total of 120 slides (14 × 12 × 1 mm) were produced from 5 different RMC materials (GC Cerasmart [GC]; Brilliant Crios [BC]; Grandio blocs [GB]; Katana Avencia [KA]; and KZR-CAD HR 2 [KZR]) and sandblasted using 50 ㎛ Al₂O₃ particles. Each RMC material was divided into six groups according to the surface conditioning (SC) method as follows: control (G1), silane primer (G2), silane-free universal adhesive (G3), silane-containing universal adhesive (G4), silane primer and silane-free universal adhesive (G5), and silane primer and silane-containing universal adhesive (G6). Three cylindric specimens made from resin cement (Bifix QM) were polymerized over the treated surface of each slide (n = 12). After thermal cycling (10000 cycles, 5 - 55℃), µSBS test was performed and failure types were evaluated using a stereomicroscope. Data were analyzed using 2-way ANOVA and Tukey tests (α = .05). RESULTS. µSBS values of specimens were significantly affected by the RMC type and SC protocols (P < .001) except the interaction (P = .119). Except for G2, all SC protocols showed a significant increase in µSBS values (P < .05). For all RMCs, the highest µSBS values were obtained in G4 and G6 groups. CONCLUSION. Only silane application did not affect the µSBS values regardless of the RMC type. Moreover, the application of a separate silane in addition to the universal adhesives did not improve the µSBS values. Silane-containing universal adhesive was found to be the best conditioning method for RMCs.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.5
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• pp.45-51
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• 2018

Roll forming refers to the production of long plate-molded products, such as panels, pipes, tubes, channels, and frames, by continuously causing the bending deformation to thin plates using rotating rolls. As the roll forming method has advantages in terms of mass production because of its excellent productivity, the size of the roll forming industry has been continuously increasing and the roll forming method is increasingly being used in diverse industrial fields as a very important processing method. Furthermore, as the roll forming method mainly depends on the continuous bending deformation of the plate materials, the time and the cost of the heterogeneous materials developed in the process are relatively large when considered from the viewpoint of plastic working because many processes are continuously implemented. The existing studies on roll forming manufacturing have reported the loss of large amounts of time and materials when the raw materials or product types were changed; further, they have stated that the use of this method can hardly guarantee the uniformity of the formed shapes and the consistency in terms of size and cannot detect all the defects occurring during the mass production and related to the dimensions. Therefore, in this research, a real-time process data-based smart roll forming method that can be applied to multiple products was studied. As a result, a roll forming system was implemented that remembers and automatically sets the changes in the finely adjusted values of the supplied quantities of individual heterogeneous materials so that the equipment setting changing time for heterogeneous material replacements or changes in the products being produced can be shortened. It also secures the uniformity of the products so that more competitive and precise slide-rail products can be mass-produced with improvements in the quality, price, and productivity of the products.

• Geomechanics and Engineering
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• v.18 no.3
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• pp.315-328
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• 2019

This paper presents an investigation on bearing capacity, load-settlement behavior and safety factor of rock-soil slopes reinforced using geogrid-box method (GBM). To this end, small-scale laboratory studies were carried out to study the load-settlement response of a circular footing resting on unreinforced and reinforced rock-soil slopes. Several parameters including unit weight of rock-soil materials (loose- and dense-packing modes), slope height, location of footing relative to the slope crest, and geogrid tensile strength were studied. A series of finite element analysis were conducted using ABAQUS software to predict the bearing capacity behavior of slopes. Limit equilibrium and finite element analysis were also performed using commercially available software SLIDE and ABAQUS, respectively to calculate the safety factor. It was found that stabilization of rock-soil slopes using GBM significantly improves the bearing capacity and settlement behavior of slopes. It was established that, the displacement contours in the dense-packing mode distribute in a broader and deeper area as compared with the loose-packing mode, which results in higher ultimate bearing load. Moreover, it was found that in the loose-packing mode an increase in the vertical pressure load is accompanied with an increase in the soil settlement, while in the dense-packing mode the load-settlement curves show a pronounced peak. Comparison of bearing capacity ratios for the dense- and loose-packing modes demonstrated that the maximum benefit of GBM is achieved for rock-soil slopes in loose-packing mode. It was also found that by increasing the slope height, both the initial stiffness and the bearing load decreases. The results indicated a significant increase in the ultimate bearing load as the distance of the footing to the slope crest increases. For all the cases, a good agreement between the laboratory and numerical results was observed.

• Earthquakes and Structures
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• v.15 no.6
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• pp.639-654
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• 2018

Rocking motion have been used for achieving the 'resilient buildings' against earthquakes in recent studies. Low-rise buildings, unlike the tall ones, because of their small aspect ratio tend to slide rather than move in rocking mode. However, since rocking is more effective in seismic response reduction than sliding, it is desired to create rocking motion in low-rise buildings too. One way for this purpose is making the building's structure rock on its internal bay(s) by reducing the number of bays at the lower part of the building's skeleton, giving it a mushroom form. In this study 'mushroom skeleton' has been used for creating multi-story rocking regular steel buildings with square plan to rock on its one-by-one bay central lowest story. To show if this idea is effective, a set of mushroom buildings have been considered, and their seismic responses have been compared with those of their conventional counterparts, designed based on a conventional code. Also, a set of similar buildings with skeleton stronger than code requirement, to have immediate occupancy (IO) performance level, have been considered for comparison. Seismic responses, obtained by nonlinear time history analyses, using scaled three-dimensional accelerograms of selected earthquakes, show that by using appropriate 'mushroom skeleton' the seismic performance of buildings is upgraded to mostly IO level, while all of the conventional buildings experience collapse prevention (CP) level or beyond. The strong-skeleton buildings mostly present IO performance level as well, however, their base shear and absolute acceleration responses are much higher than the mushroom buildings.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.2
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• pp.29-37
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• 2019

In this study, emotional adjectives about the operating sound quality of the vehicle power seat are constructed, and the effectiveness of the emotional adjectives are verified by evaluating the operating sound quality. First, emotional adjectives were collected from the literature related to the automobile field and other sound qualities. A questionnaire was made using these adjectives. The questionnaire was designed to be able to select all adjectives that could express the operating noise of the power seat slide adjuster by applying the multiple- response method. Next, a subjective sound quality evaluation was conducted using the emotional adjectives. In the evaluation, we first recorded the operating noise for two power seats. Second, the subjective sound quality evaluation was performed on the recorded operating noise using a loudspeaker. Finally, through a statistical analysis on the sound quality evaluation results, the relationship between the semantic space and the preference score was verified, and the validity of the emotional adjectives was verified.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.624-631
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• 2019

The purpose of this study was to observe the influence of adhesive force of lifter on powdered fingermark. First, an experiment was conducted to measure the adhesive force of five kinds of lifters. Second, each fingermark deposited on slide glass was developed using four kinds of powders. Then, these were transferred to lifter, and the quality of the transferred fingermark was observed. As a result of measuring the adhesive force of the lifter using the ASTM D3121-17 rolling ball tack method, the difference in adhesion between the lifters except the gelatin lifter was small. Also, it was confirmed that the quality of the transferred fingermark was not significantly related to the adhesive force of the lifter. However, if the quality of the transferred fingermark is not good when transferring to a gelatin lifter which is a lifter having a weak adhesive force, additional transfer is possible.

• PNF and Movement
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• v.19 no.1
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• pp.19-29
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• 2021

Purpose: This study aimed to compare the effects of a four-week scapular stabilization exercise program using the PNF technique on scapular symmetry and range of flexion motion (ROM), pain, function, and quality of life (QOL) in post-mastectomy women with breast cancer. Methods: This study included 20 women divided into an experimental group (n = 10) and a control group (n = 10). All patients performed complex decongestive physiotherapy for 40 min daily, five times per week for four weeks. The experimental group performed the extra scapular stabilizing exercise program using the PNF technique for 50 min daily, five times per week for four weeks. Scapular symmetry, shoulder flexion ROM, pain and function, and QOL were subsequently assessed. For ROM measurement, the range of shoulder flexion was measured using a clinometer smart phone application; the pain of the shoulder was measured using the visual analogue scale (VAS); the scapular position was measured using a lateral scapular slide test (LSST); the level of pain and functional activity was measured using the Shoulder Pain and Disability Index (SPADI); and the QOL was measured using Functional Assessment of Cancer Therapy-Breast. Results: There were significant differences in shoulder flexion ROM, VAS, SPADI, and LSST 0˚ and 45˚ when the experimental group was compared with the control group (p < 0.05). After the intervention, there was an improved within-group change in the ROM, SPADI, LSST, and QOL in both the experimental and control groups. Conclusion: These findings suggest that a scapular stabilization exercise program using the PNF technique may be used as a possible treatment option for post-mastectomy women with breast cancer that aims to improve scapular position, shoulder ROM and function, and QOL.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.45-52
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• 2008

The slide resynchronization attack on Grain-v1 was proposed in [5]. Given the keystream sequence, this attack can generate the 1-bit shifted keystream sequence generated by Grain-v1. In this paper, extending the attack proposed in [5], we propose the key recovery attack on Grain-v1 using the related-key. Using the weakness of the initialization procedure of Grain-v1, this attack recover the master key with $2^{25.02}$ Ⅳs and $2^{56}$ time complexity. This attack is the first known key recovery attack on Grain-v1.