• The korean journal of orthodontics
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• v.41 no.6
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• pp.447-453
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• 2011

Objective: We compared the shear bond strength (SBS) of lingual retainers bonded to bovine enamel with three different resins using direct and indirect methods. Methods: Both ends of pre-fabricated twisted ligature wires were bonded to bovine enamel surfaces using Light-Core, Tetric N-Flow, or Transbond XT. Phosphoric acid-etched enamel surfaces were primed with One-Step prior to bonding with Light-Core or Tetric N-Flow. Transbond XT primer was used prior to bonding with Transbond XT. After 24 hours in water at $37^{\circ}C$, we performed SBS tests on the samples. We also assigned adhesive remnant index (ARI) scores after debonding and predicted the clinical performance of materials and bonding techniques from Weibull analyses. Results: Direct bonding produced significantly higher SBS values than indirect bonding for all materials. The SBS for Light-Core was significantly higher than that for Tetric N-Flow, and there was no significant difference between the direct bonding SBS of Transbond XT and that of Light-Core. Weibull analysis indicated Light-Core performed better than other indirectly bonded resins. Conclusions: When the SBS of a wire retainer is of primary concern, direct bonding methods are superior to indirect bonding methods. Light-Core may perform better than Transbond XT or Tetric N-Flow when bonded indirectly.

• Journal of the Korean Society of Costume
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• v.52 no.3
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• pp.149-160
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• 2002

Symbolism found in a certain object inherits characteristics from the culture that contains the objects. The purpose of this study was investigate the formative beauty of Korean trousers twisted the pieces together based on the way of Korean thinks and the Topology. The shape is formed by cutting from the fabric. From the perspective of semiology, the fabric and the pattern shape correspond to ground and figure. Ground and figure are identical with the principle of the whole and the part, which is the same in Korea, China, and the West. But In Korea, the 3-dimensional garment is made by adding a twist. This is very important and defines the difference in the way of thinking and topology. Korean trousers consist of three parts : Hury, Marupok, and Sapok. The small Sapok can be made by removing the Marupok and large Sapok (figure) from the fabric (ground) when making Korean trousers. A Mobius strip is made when the large Sapok is adjoined with the small Sapok by reversing the small Sapok, making a 180$^{\circ}$twist and then stitching together. The theory of Mobius strip can be applied in Joining Bajiburi. thus when the trousers are completed the Klein's bottle is seen because of the 2 existing Mobius strop. The theory of Mobius strip can be applied in Joining Bajiburi, thus when the trousers are completed the Klein's bottle is seen because of the 2 existing Mobius strip. Hury is cylinder while the small and large Sapok make up the Mobius strip. As a result, Mobius strip, Kleins'bottle, protective plan can be applied in cutting Hanbok used in the countryside, so I have come to see that the traditional Korean way of thinking is closely related to the theory of topological.

• Investigative Magnetic Resonance Imaging
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• v.18 no.3
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• pp.253-257
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• 2014

Wandering spleen is a rare clinical condition caused by lax splenic suspensory ligaments. The laxity of ligaments causes torsion of splenic vascular pedicle. CT scan of a 7-year-old girl with abdominal pain showed a non-enhancing lobular mass in lower abdomen. Small bowel loops were located at the right-sided abdomen and colonic loops at the left-sided abdomen. MRI scan showed non-enhancing heterogeneous mass with twisted vascular pedicle. To our knowledge, only a few cases have been reported about wandering spleen diagnosed on MRI.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.241.2-241.2
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• 2014

We present highly transparent liquid crystal displays (LCDs) using hybrid films based on carbon nanomaterials, metal grid, and indium-tin-oxide (ITO) grid. Carbon based nanomaterials are used as transparent electrodes because of high transmittance. Despite of their high transmittance they have relatively high sheet resistance. To solve this problem, we applied grid and made hybrid conductive films based on carbon nanomaterials. Conventional photolithography processes were used to make a grid pattern of metal and ITO. To fabricate transparent conductive films, carbon nanotube (CNT) ink was spin coated on the grid pattern. The transparency of the conductive film was controlled by shape and size of the grid pattern and the thickness of CNT films. The optical transmittance of CNT-based hybrid films is 92.2% and sheet resistance is also reduced to $168{\Omega}/square$. These substrates were used for the fabrication of typical twisted nematic (TN) LCD cells. From the characteristics of LCD devices such as transmittance, operating voltage, voltage holding ratio our devices were comparable to those of pristine ITO substrates. The result shows that the hybrid conductive films based on carbon nanomaterials could be alternative of ITO for the highly transparent LCDs.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.121-129
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• 2020

This paper described a laboratory investigation of micro hydropower at lower head water in a free vortex flow. The vortex height, turbine rotation and torque for straight blade with inner curved edge, twisted blade and curved blade were investigated at the flow rate of 0.0069 ㎥/s in the inlet channel. The results showed that the optimum vortex strength occurred within the range of the diameter of basin to the outlet diameter ratios of 0.17~18.5. The power output and efficiency of straight blade were higher as compared to other blades. The highest amount of generated energy was 12.33 W, the torque was 0.91 N·m and the highest efficiency by considering effective head was 29.5 %, whereas the highest efficiency by considering vortex height was 80.5 % at the rotational speed of 132 rpm. The water vortex velocity of straight blade was about 2.8 times larger than the mean velocity in the inlet channel.

• Ocean and Polar Research
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• v.32 no.4
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• pp.369-377
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• 2010

To characterize ecotoxicological responses to a natural estrogen, $17{\beta}$-estradiol, we evaluated the life-history of the parental ($F_0$) and first generation ($F_1$) of the harpacticoid copepod, Tigriopus japonicus sensu lato. We evaluated the survival of nauplii and copepodites, the number of days until the emergence of copepodites and adult males, the sex ratio, brooding success, and the first brooding day of adult females. No significant differences in the survival rate were noted in response to treatments with different concentrations of $17{\beta}$-estradiol. However, $17{\beta}$-estradiol induced developmental delay and skewed the sex ratio toward males. Copepod development was delayed significantly in the 0.1 and $1\;{\mu}g\;l^{-1}$ $17{\beta}$-estradiol treatment groups relative to the control group, with a more pronounced delay in the $F_1$ group. Body length and biomass were significantly smaller in the $17{\beta}$-estradiol treated groups than in the controls. The male emergence of T. japonicus s.l. was very high in the 10 and $30\;{\mu}g\;l^{-1}$ $17{\beta}$-estradiol treatment group. Furthermore, exposure to $17{\beta}$-estradiol resulted in morphological deformities such as shrinking and swelling of the urosome, twisted setae of the caudal rami, setal loss of swimming legs, abnormal segmentation of antennules, and dwarfism.

• Composites Research
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• v.30 no.6
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• pp.331-337
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• 2017

The composite lattice structures have advantages of high specific stiffness and strength and are mainly applied to the structures of launch vehicles that carry the compressive load. However, since these structures are manufactured by filament winding technology, there are some defects and voids found in the knots. For these reasons, the stiffness and strength of the lattice structures have to be compared with finite element model for predicting design load. But, the full scale test is difficult because time and space are limited and the shape of structure is complex, and hence the simple and reliable test methods for examination of stiffness are needed. In this paper, subelements of composite lattice structures were prepared and compressive and bending test were conducted for examination of stiffness of helical and hoop rib. Test methods for subelements of composite lattice structures that has curved and twisted shape were supposed and compared with finite element analysis results.

• Tribology and Lubricants
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• v.32 no.5
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• pp.141-146
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• 2016

The diketopyrrolopyrrole (DPP) pigment is a bicyclic 8-π-electron system containing two lactam units. Typical DPP derivative pigments have melting points of over 350°C and very low solubility in most solvents, and show absorption in the visible region with a molar extinction coefficient of 33,000 dm²mol⁻¹ and strong photoluminescence with maxima in the range 500–600 nm. X-ray structure analyses of DPP show that the whole molecule is almost in one plane. The phenyl rings are twisted out of the heterocyclic plane and the intermolecular hydrogen bonding between neighboring lactam NH and carbonyl units influences the structure of the DPP pigment in the solid state. In this study, mono-N-alkylation and mono-N-arylation were undertaken for Pigment Red 264 or Pigment Orange 73 with alkyl halide and aryl halide, respectively, in the presence of sodium tert-butoxide as a base catalyst to improve the solubility of DPP pigments and their application as CO₂ indicators. The synthetic yield was in the range 11–88%. The indicator dyes are highly soluble in organic solvents and shows pH-dependent absorption (λ_max 501 and 572 nm for the protonated and deprotonated forms, respectively) and emission (λ_max 524 and 605 nm for the protonated and deprotonated forms, respectively) spectra. The mono-N-alkylated and mono-N-arylated DPP pigment was identified by ¹H-NMR (¹H-Nuclear Magnetic Resonance Spectrometer), FT-IR (Fourier Transform Infrared Spectroscopy), and MS (Mass Spectrometry). According to the results of color and hue properties obtained by a color matching analyzer, the synthesized DPP pigment material can be used as a CO₂ indicator.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.22-40
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• 2015

Cellulose fibers is one of the most abundant in nature. It has many distinctive features: abundant in nature, biodegradable, non-toxic, eco-friendly, sustainable, easy to fabricate, hydrophilic, and cost-effective. Cellulose fibers, known as pulp, is produced from cellulose-containing materials by the pulping process. As the raw material, wood has been most commonly used while recycled pulp has been also used to some degree. Thus, pulp usually refers to wood pulp. Generally, the pulp and paper industry is regarded as the commodity market where the cost should be much more important than the quality. It also belongs to a mature market where the growth is slow, or even in decline. Accordingly, technological development has been rather stagnant for the industry. Recently, however, the pulp and paper industry has faced very serious challenges. First, due to digital technology, there has been a steady decline in the need for pulp and paper products. The digital industry has continuously replaced printed products such as books, newspapers, and magazines. Second, there has been a trend initiated by developed countries to limit the use of wood as the raw material for the sake of environmental protection. This forces the industry to find a more efficient use of wood pulp as well as finding alternative, non-wood sources. Third, as an individual becomes wealthier and more conscious of health-care, the quality of a product becomes more important than the cost. Thus, a paradigm shift is needed from the cost-conscientious to the quality conscientious. The objective of this article is to review the technologies aimed at engineering cellulose fibers for producing high-value added paper products.

• Journal of Korean Physical Therapy Science
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• v.10 no.1
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• pp.222-231
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• 2003

The ACL(Anterior cruciate ligament) is the smallest of the four main ligaments of the knee, but it is the primary stabilizer. Injuries have a tendency to occur when the foot is firmly planted and the knee is twisted. Any sports that requires acceleration, change of direction and deceleration can increase the chances of suffering an ACL tear. The incidence of severe knee sprains that involve the ACL are at an all-time high. Since 1980, the number of these injuries have increased at least three-fold. Although the rate of increase has been much less dramatic since the middle 1980s, even the ultra-modem releasable ski binding has not been able to start reducing the incidence of ACL injuries. An ACL injury prevention program developed for downhill skiers by the Vermont Safety Research group emphasized increasing awareness of situations that can potentially result in an ACL injury and pre-planning strategies if events, leading to these situations, begin to fall in place. As part of the above study by Ettlinger et al., an educational prevent program was developed to teach these principles and thus reduce the rate of serious knee injuries. Four thousand instructors and patrol at 20 ski resorts who received the training had a 62% decline in serious knee injuries compared to a similar group that did not receive this training. Whenever you fall, try not to fully straighten your legs. Don't try to get up until you've stopped sliding(unless you are try to avoid an obstacle or other skier). When you're down, stay down. And don't land on your hand. So, if you feel yourself falling: arms forward, ski plates together, hands over knee. Then you will be able to save your ACL.