• Journal of the Korean institute of surface engineering
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• v.39 no.2
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• pp.64-69
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• 2006

Nanoscale task such as nanolithography and nanoindenting is a challenging work that is beyond the capabilities of human sensing and precision. Since surface forces and intermolecular forces dominate over gravitational and other more intuitive forces of the macro world at the nanoscale, a user is not familiar with these novel nanoforce effects. In order to overcome this scaling barrier, haptic interfaces that consist of visual and force feedback at the macro world have been used with an Atomic Force Microscope (AFM) as a manipulator at the nanoscale. In this paper, a nanoscale virtual coupling (NSVC) concept is introduced and the relationship between performance and impedance scaling factors of velocity (or position) and force are explicitly represented. Experiments have been performed for nanoindenting and nanolithography with different materials in the nanoscale virtual surface. The interaction forces (non contact and contact nanoforces) between the AFM tip and the nano sample are transmitted to the operator through the haptic interface.

• ETRI Journal
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• v.44 no.3
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• pp.491-503
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• 2022

Metal-oxide-semiconductor field-effect transistors (MOSFETs) are continuously scaling down in the nanoscale region to improve the functionality of integrated circuits. The scaling down of MOSFET devices causes short-channel effects in the nanoscale region. In nanoscale region, leakage current components are increasing, resulting in substantial power dissipation. Very large-scale integration designers are constantly exploring different effective methods of mitigating the power dissipation. In this study, a transistor-level input-controlled stacking (ICS) approach is proposed for minimizing significant power dissipation. A low-power ICS approach is extensively discussed to verify its importance in low-power applications. Circuit reliability is monitored for process and voltage and temperature variations. The ICS approach is designed and simulated using Cadence's tools and compared with existing low-power and high-speed techniques at a 22-nm technology node. The ICS approach decreases power dissipation by 84.95% at a cost of 5.89 times increase in propagation delay, and improves energy dissipation reliability by 82.54% compared with conventional circuit for a ring oscillator comprising 5-inverters.

• Wind and Structures
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• v.38 no.4
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• pp.261-275
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• 2024

Before performing an experimental study on the downburst-generated wave, it is necessary to examine the scale effects and corresponding corrections or compensations. Analysis of similarity is conducted to conclude the non-dimensional force ratios that account for the dynamic similarity in the interaction of downburst with wave between the prototype and the scale model, along with the corresponding scale factors. The fractional volume of fluid (VOF) method in association with the impinging jet model is employed to explore the characteristics of the downburst-generated wave numerically, and the validity of the proposed scaling method is verified. The study shows that the location of the maximum radial wind velocity in a downburst-wave field is a little higher than that identified in a downburst over the land, which might be attributed to the presence of the wave which changes the roughness of the underlying surface of the downburst. The impinging airflow would generate a concavity in the free surface of the water around the stagnation point of the downburst, with a diameter of about two times the jet diameter (D_jet). The maximum wave height appears at the location of 1.5D_jet from the stagnation point. Reynolds number has an insignificant influence on the scale effects, in accordance with the numerical investigation of the 30 scale models with the Reynolds number varying from 3.85 × 10⁴ to 7.30 × 10⁹. The ratio of the inertial force of air to the gravitational force of water, which is denoted by G, is found to be the most significant factor that would affect the interaction of downburst with wave. For the correction or compensation of the scale effects, fitting curves for the measures of the downburst-wave field (e.g., wind profile, significant wave height), along with the corresponding equations, are presented as a function of the parameter G.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.77-84
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• 2008

Experimental study was conducted to clarify the importance of buoyancy effects in laminar lifted flames which have been well understood by cold jet similarity theory. To evaluate buoyancy effects, lifted flame behaviors were systematically observed in methane and propane lifted flames diluted with He as changing the fuel nozzle diameter from 0.1 to 6 mm. Important physical parameters such as fuel strength, flame stretch and flame curvature, which were derived through simple physical scaling laws, were estimated. It is experimentally proven that buoyancy effects are important in relatively large fuel nozzle diameter and large fuel dilution with He. The results of Chen et al., which displayed the existence of stably lifted flames for 0.5

• Journal of Periodontal and Implant Science
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• v.51 no.3
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• pp.147-162
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• 2021

Purpose: This systematic review and meta-analysis was conducted to assess the effects of glycine powder air-polishing (GPAP) in patients during supportive periodontal therapy (SPT) compared to hand instrumentation and ultrasonic scaling. Methods: The authors searched for randomized clinical trials in 8 electronic databases for relevant studies through November 15, 2019. The eligibility criteria were as follows: population, patients with chronic periodontitis undergoing SPT; intervention and comparison, patients treated by GPAP with a standard/nozzle type jet or mechanical instrumentation; and outcomes, bleeding on probing (BOP), patient discomfort/pain (assessed by a visual analogue scale [VAS]), probing depth (PD), gingival recession (Rec), plaque index (PI), clinical attachment level (CAL), gingival epithelium score, and subgingival bacteria count. After extracting the data and assessing the risk of bias, the authors performed the meta-analysis. Results: In total, 17 studies were included in this study. The difference of means for BOP in patients who received GPAP was lower (difference of means: -8.02%; 95% confidence interval [CI], -12.10% to -3.95%; P<0.00001; I²=10%) than that in patients treated with hand instrumentation. The results of patient discomfort/pain measured by a VAS (difference of means: -1.48, 95% CI, -1.90 to -1.06; P<0.001; I²=83%) indicated that treatment with GPAP might be less painful than ultrasonic scaling. The results of PD, Rec, PI, and CAL showed that GPAP had no advantage over hand instrumentation or ultrasonic scaling. Conclusions: The findings of this study suggest that GPAP may alleviate gingival inflammation more effectively and be less painful than traditional methods, which makes it a promising alternative for dental clinical use. With regards to PD, Rec, PI, and CAL, there was insufficient evidence to support a difference among GPAP, hand instrumentation, and ultrasonic scaling. Higher-quality studies are still needed to assess the effects of GPAP.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.2
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• pp.238-245
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• 2017

This paper deals with the scale effects of warhead on concrete penetration. We investigated the scale effects using finite element analysis and Young's penetration equation. As the scale of penetration test decreases, the strain rate effects of target increases, and then strength of concrete target increases. This means the residual velocity and penetration depth of warhead decreases as the test model size decreases. Young's penetration equations are transformed with various penetrator mass and scale cases as a function of scale ratio. Penetration distance and residual velocity are not simply changed by the geometric scaling law.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.790-797
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• 2011

Hydrodynamic similarity was analyzed by employing scaling factor in three phase fluidized beds. The scaling factor was defined based on the holdups of gas, liquid and solid particles and effectivity volumetric flux of fluids between the two kinds of fluidized beds with different column diameter. The column diameter of one was 0.102 m and that of the other was 0.152 m. Filtered compressed air, tap water and glass bead of which density was 2,500 kg/$m^3$ were used as gas, liquid and solid phases, respectively. The individual phase holdups in three phase fluidized beds were determined by means of static pressure drop method. Effects of gas and liquid velocities and particle size on the scaling factors based on the holdups of each phase and effective volumetric flux of fluids were examined. The deviation of gas holdup between the two kinds of three phase fluidized beds decreased with increasing gas or liquid velocity but increased with increasing fluidized particle size. The deviation of liquid holdup between the two fluidized beds decreased with increasing gas or liquid velocity or size of fluidized solid particles. The deviation of solid holdup between the two fluidized beds increased with increasing gas velocity or particle size, however, decreased with increasing liquid velocity. The deviation of effective volumetric flux of fluids between the two fluidized beds decreased with increasing gas velocity or particle size, but increased with increasing liquid velocity. The scaling factor, which was defined in this study, could be effectively used to analyze the hydrodynamic similarity in three phase fluidized processes.

• Journal of Dental Anesthesia and Pain Medicine
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• v.24 no.1
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• pp.19-35
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• 2024

Background: This study investigated a safe and effective bolus dose and lockout time for patient-controlled sedation (PCS) with dexmedetomidine for dental treatments. The depth of sedation, vital signs, and patient satisfaction were investigated to demonstrate safety. Methods: Thirty patients requiring dental scaling were enrolled and randomly divided into three groups based on bolus doses and lockout times: group 1 (low dose group, bolus dose 0.05 ㎍/kg, 1-minute lockout time), group 2 (middle dose group, 0.1 ㎍/kg, 1-minute), and group 3 (high dose group, 0.2 ㎍/kg, 3-minute) (n = 10 each). ECG, pulse, oxygen saturation, blood pressure, end-tidal CO₂, respiratory rate, and bispectral index scores (BIS) were measured and recorded. The study was conducted in two stages: the first involved sedation without dental treatment and the second included sedation with dental scaling. Patients were instructed to press the drug demand button every 10 s, and the process of falling asleep and waking up was repeated 1-5 times. In the second stage, during dental scaling, patients were instructed to press the drug demand button. Loss of responsiveness (LOR) was defined as failure to respond to auditory stimuli six times, determining sleep onset. Patient and dentist satisfaction were assessed before and after experimentation. Results: Thirty patients (22 males) participated in the study. Scaling was performed in 29 patients after excluding one who experienced dizziness during the first stage. The average number of drug administrations until first LOR was significantly lower in group 3 (2.8 times) than groups 1 and 2 (8.0 and 6.5 times, respectively). The time taken to reach the LOR showed no difference between groups. During the second stage, the average time required to reach the LOR during scaling was 583.4 seconds. The effect site concentrations (Ce) was significantly lower in group 1 than groups 2 and 3. In the participant survey on PCS, 8/10 in group 3 reported partial memory loss, whereas 17/20 in groups 1 and 2 recalled the procedure fully or partially. Conclusion: PCS with dexmedetomidine can provide a rapid onset of sedation, safe vital sign management, and minimal side effects, thus facilitating smooth dental sedation.

• Journal of Periodontal and Implant Science
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• v.48 no.5
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• pp.295-304
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• 2018

Purpose: This study was undertaken to evaluate the clinical and microbiological effects of an erythritol powder air-polishing device (EPAP) as a supplement to scaling and root planing (SRP) therapy in patients with moderate chronic periodontitis. Methods: Clinical and microbiological evaluations were performed at 21 sites treated with SRP (control) and 21 sites treated with SRP+EPAP (test). All examinations were performed before treatment, 1 month after treatment, and 3 months after treatment. Results: There were no significant clinical differences between the test group and the control group. Microbiological analysis revealed that the relative expression level of Porphyromonas gingivalis was significantly lower in the test group than in the control group at 1 month after treatment. Clinical and microbiological results showed improvements at 1 month compared to baseline; in contrast, the results at 3 months after treatment were worse than those at 1 month after treatment. Conclusions: In this study, both SRP and SRP+EPAP were clinically and microbiologically effective as non-surgical periodontal treatments. In particular, the SRP+EPAP group showed an antimicrobial effect on P. gingivalis, a keystone bacterium associated with the onset of chronic periodontitis, in a short-term period. Periodic periodontal therapy, at intervals of at least every 3 months, is important for sustaining the microbiological effects of this treatment.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.725-737
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• 1999

The present study was performed to evaluate the clinical effects following local application of 30% minocycline strip(polycaprolactone), 2% minocycline gel(hydrocarbon gel) and 12% minocycline strip(polylactide, Minodent) to augment scaling and root planing in patients with chronic adult periodontitis. Forty teeth with periodontitis were enrolled in the study anddistributed into 4 groups including control group. All patients performed standardized oral hygiene instructions and mechanical debridement at the beginning of the study and then each local delivery drugs were inserted into periodontal pocket in each groups. Examinations regarding plaque index(PI), papillary bleeding index (PBI), probing pocket depth (PPD) were carried out at 0, 2, 4 weeks. All experimental groups showed statistically significant differences between baseline and 2 and 4 weeks in every clinical indices. Especially, 30%minocycline strip and Minodent group showed a significant improvement in PBI at 2 weeks and in PPD at 2 and 4 weeks. In conclusion, highly bio-resorbable Minodent delivered subgingivally as an adjunct to scaling and root planing induces better clinical effects for periodontal health than 2% minocycline gel and control group.