• The korean journal of orthodontics
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• v.51 no.3
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• pp.157-165
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• 2021

Objective: This study aimed to identify the clinical effectiveness of two different penetration depths of micro-osteoperforations (MOPs) on the rate of orthodontic tooth movement. Methods: Twenty-four patients requiring the removal of the upper first premolar teeth were selected and randomly divided into two groups. The control group participants did not undergo MOPs. Participants in the experimental group underwent three MOPs each at 4-mm (MOP-4) and 7-mm (MOP-7) depths, which were randomly and equally performed to either the left or right side distal to the canine. The retraction amount was measured on three-dimensional digital models on the 28th day of retraction. MOP-related pain was measured using a visual analog scale (VAS). Between-group statistical differences in the VAS scores were determined using an independent t-test and those in canine retraction were determined using analysis of variance and post-hoc Tukey test. Results: No significant difference was found between the MOP-4 (1.22 ± 0.29 mm/month) and MOP-7 (1.29 ± 0.31 mm/month) groups in terms of the canine retraction rate. Moreover, both the groups demonstrated a significantly higher canine movement than the control group (0.88 ± 0.19 mm/month). MOPs did not significantly affect the mesialization of the posterior teeth (p > 0.05). Moreover, the pain scores in the MOP-4 and MOP-7 groups were similar and showed no statistically significant difference. Conclusions: Three MOPs with a depth of 4 mm can be performed as an effective method to increase the rate of tooth movement. However, three MOPs with depths of 4-7 mm does not additionally enhance tooth movement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.93-105
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• 1993

In this paper, the maximum scour depths at piers located in the Bo Cheong Stream, which is a tributary in the Geum River System, were calculated and compared using 24 local pier scour equations. The equations were classified as six groups by non-dimensional types of equations. The geometric data in the stream bed and pier data at San Seong, Yi Pyung and San Gye, which are IHP data collection stations, were utilized for applying the scour equations. The geometric data in the stream bed were obtained by analyzing the bed material sampled in three stations which are in the left side, middle and right side for stream direction. The maximum flow velocities at maximum flow depths which were measured from 1982 to 1991, were used as the hydraulic flow data. The pier data for predicting pier scour depths were measured in the fields. The maximum pier scour depths calculated using the equations were compared with the held scour depths measured in the streams or rivers in the world. Arunachalam, Shen-Karaki III, Jain-Fischer equations are selected as the proper local scour equations for predicting the maximum local scour depths at piers in the Bo Cheong Stream. Inglis-Lacey and Shen-Karaki II equations are applicable in case of rapid flows conditions in which Froude number is over 0.3. Froehlich, Laursen I, Laursen II, Neill, Melville equations are applicable in the slow flow conditions in which Froude number is less than 0.3. Blench equation or Inglis-Poona equation varies rapidly by changing Froude numbers. Therefore the equations should not be used without careful considerations in selecting the applicable ranges. The maximum local scour depths calculated using Sarma-Krishnamurthy, Ahmad, Coleman, Varzeliotis, Larras, Bata, Chitale, Venkatadri, Basik-Basamily-Ergun, U.S.G.S., Shen I equations are usually less than the scour depths measured in the fields.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.450-454
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• 1998

Four groups each containing 48 seven-day-old broiler chicks were reared for 7 weeks during winter on rice husk litter spread to depths of 20, 30, 40 or 50 mm. Broiler performance was evaluated in terms of weight gain, feed consumption, feed efficiency and production number. Litter dampness was determined and coccidial oocyst populations were counted at different weeks of age. The depth of litter did not significantly affect live weight gain, feed consumption, feed conversion ratio, liveability or production number. Variation in moisture contents of litter was observed but the coccidial oocysts count per gramme of litter was within the safety level and therefore, there was no outbreak of coccidiosis in any group. Use of rice husk litter at different depths (20 to 50 mm) did not cause any breast blisters or leg abnormalities. It was concluded that rice husk can be used as litter at depths of between 20 and 50 mm during winter to raise broilers without affecting performance characteristics and health of birds.

• Structural Engineering and Mechanics
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• v.60 no.3
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• pp.387-404
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• 2016

In this paper, the response and failure of sharp-notched 6061-T6 aluminum alloy circular tubes with five different notch depths of 0.4, 0.8, 1.2, 1.6 and 2.0 mm subjected to cyclic bending were experimentally and theoretically investigated. The experimental moment-curvature relationship exhibits an almost steady loop from the beginning of the first cycle. And, the notch depth has almost no influence on its relationship. However, the ovalization-curvature relationship exhibits a symmetrical, increasing, and ratcheting behavior as the number of cycles increases. In addition, a higher notch depth of a tube leads to a more severe unsymmetrical trend of the ovalization-curvature relationship. Focusing on the aforementioned relationships, the finite element software ANSYS was used to continue the related theoretical simulation. Furthermore, the five groups of tubes tested have different notch depths, from which five unparallel straight lines can be observed from the relationship between the controlled curvature and the number of cycles required to produce failure in the log-log scale. Finally, a failure model was proposed to simulate the aforementioned relationship. Through comparison with the experimental data, the proposed model can properly simulate the experimental data.

• Water for future
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• v.28 no.2
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• pp.145-154
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• 1995

The various analyses of the historical rainfall data need to be utilized in a hydraulic engineering project. The probability distributions of the rainfall events according to annual maximum continuous rainfall depths are studied for the hydrologic frequency analysis. The bivariate normal distribution, the bivariate lognormal distribution, and the bivariate gamma distribution are applied to the rainfall events composed of rainfall depths and its durations at Kangnung, Seoul, Incheon, Chupungnyung, Teagu, Jeonju, Kwangju, and Busan. These rainfall events are fitted to the the bivariate normal distribution and the bivariate lognormal distribution, but not fitted to the bivariate gamma distribution. Frequency curves of probability rainfall events are suggested from the probability distribution selected by the goodness-of-fit test.

• Journal of Korea Water Resources Association
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• v.30 no.6
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• pp.743-751
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• 1997

A thorough literatural review of researches on the experimental prediction of scour depths caused by jets was carried out to find out a measure of scour prediction. A new experimental equation for predicting scour depths due to a vortical or an inclined jet was developed from five hundreds of experimental data which were carefully reviewed and adopted from the previous researches. The developed equation shows 0.941 statistical correlation coefficient. It was found that the parameters governing the scour depth were the size of bed material, flow rate through unit width of spillway, and head drop across structure. The predicted scour depth could be expressed as the deepest scouring depth below tail water surface with correlation coefficient ${\gamma}$ = 0.941.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.255-261
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• 1998

The recent greenhouses are extremely light-weight structures and easily damaged by the strong winds due to the lack of uplift capacity of pile foundations. The uplift capacity of pile foundations are subject to the shape of the pile surface, diameter, weight, and embedded depths. etc. So, it is very important to figure out the most appropriate conditions on shape of the pile surface and it's embedding depths. to improve wind proof capability of pipe greenhouses. In this study, plane and corrugated pile surfaces were examined on their uplift capacity with 30 to 50 cm of embedding depths. The diameters of tested piles were 10 cm, 15 cm, and 20 cm, respectively. Compaction ratio of the tested soil was 80%. Each test run was repeated three times for the respective treatment. Obtained results are as follows; In all cases, as the diameter and the embedding depth were increased, the ultimate uplift capacity of the pile was also increased. And it was clear that the ultimate uplift capacity of corrugated pile was approximately two times as big as that of plain piles under same conditions.

• Journal of Environmental Health Sciences
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• v.22 no.2
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• pp.25-31
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• 1996

The species of four heavy metals (Cr, Cu, Ni and Pb) associated with sediments (viz exchangeable, carbonates, reducible, organic and residual fractions) were determined with respect to the particle sizes and depths at four locations of the lower Kumho river. In the exchangeable fraction, 3.7~19.52% of Ni and 2.8~14.81% of Pb were found, and in the carbonates fraction 2.12~19.43% of Ni and 1.39~15.42% of Pb were found. The reducible fraction retained about 8.66~44.93% of Cr, 0.41~9.79% of Cu, 17.38~35.74% of Ni and 9.5~44.89% of Pb. In the organic fraction about 0~21.06% of Cr, 2.95~35.74% of Cu, 0~14.66% of Ni and 0~10.65% of Pb were found. The residual fraction retained about 52.6~83.53% of Cr, 63.86~86.39% of Cu, 39.66~66.16% of Ni and 39.97~71.75% of Pb. The order of release or mobility of heavy metals was Ni > Pb > Cr > Cu. Mobile fraction of heavy metals by particle sizes (1.0~0.5 mm and 0.5~0.25 mm) was found to be higher in particle sizes 1.0~0.5 mm than that of 0.5~0.25 mm. The release or mobility of heavy metals by depths (0~5 cm, 5~10 cm and 10~15 cm) was found to be higher in the upper sediments than in the lower sediments, except Cu.

• ALGAE
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• v.30 no.3
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• pp.223-232
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• 2015

More than 20 and 10 clades / ecotypes of Synechococcus and Prochlorococcus, respectively, have been identified in various oceanic regions. However, their diversity has yet to be thoroughly studied in the northwest Pacific Ocean. Further, spatial distribution of Synechococcus clades in the oligotrophic oceans has been scarcely characterized. To elucidate picocyanobacterial lineage distribution in the northwest Pacific Ocean, 16S-23S internal transcribed spacer sequences of picocyanobacteria were sequenced by barcoded amplicon pyrosequencing method. Additional pyrosequencing library using a primer specific for the Synechococcus subcluster-5.1 was constructed to thoroughly understand Synechococcus diversity in the oligotrophic oceans. In warm pool area, Prochlorococcus was predominant and showed a distinct depthpartitioning between HLII and LL ecotypes. Despite low abundances, diverse Synechococcus clades appeared in the oligotrophic open ocean, showing both vertical and horizontal niche partitioning. Clade II was the predominant Synechococcus clade, especially in upper euphotic depths. In shallow and middle euphotic depths, clades UC-A, III, and CRD1 were distributed broadly. However, a distinct shift in the horizontal distribution was found at ca. $20^{\circ}N$. Conversely, clades XVII and CRD2 dominated at deep euphotic depths and constituted a higher proportion than clade II. These niche-partitioning of Synechococcus clades seemed to be related with temperature, nutrient concentration as well as iron concentration.

• Korean Journal of Human Ecology
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• v.6 no.2
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• pp.145-155
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• 1997

The purpose of this study is to analyze the body type of children's, especially torso, and to provide the fundamental data for children's clothing construction which can reflect the characteristics of their bodies. The subjects for photographic measurements are 308 elementary school children aged from 6 to 8 living in Seoul and urban area. Anthropometric measurements were performed indirectly from the pictures of subjects. The data were analyzed statistically using SPSSWIN. The results obtained from this study are as follows: 1. Through one-way ANOVA, items for heights, breaths, weight reveals the significant differences according to ages and genders. 2. Through Pearson correlation, it turns out that there are high correlation between any items of heights, but there is no correlation for item of shoulder inclination with any other items. 3. Through factor analysis of principal component model, six factors were extracted which covers 83.6% of the whole information. The first factor represents the items of heights which relates with linearity. The second factor describes the items of breaths, depths, and weight in relation with laterality. The third factor were gathered with depths of front and back in relation with posture of side, which proves as important one to characterize the children's torso. The other factors represents the items of posture of neck, depths in neck, shoulder inclination, respectively. 4. Through one-way ANOVA in factor by group, and Scheffe multi comparison test for each group, the factor 1 that is related with linearity reveals the significant differences according to ages and genders.