• Journal of the korean society of oceanography
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• v.31 no.2
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• pp.75-88
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• 1996

The analytic and numerical solution of the 1$\frac{1}{2}$-layer and 2$\frac{1}{2}$-layer models are derived. The large coastal-sea level drop and the fast westward speed of the anticyclonic gyre due to strong offshore winds using two ocean models are investigated. The models are forced by wind stress fields similar in structure to the intense mountain-pass jets(${\sim}$20 dyne/$cm^{2}$) that appear in the Gulfs of Tehuantepec and Papagayo in the Central America for periods of 3${\sim}$7 days. Analytic and numerical solutions compare favorably with observations, the large sea-level drop (${\sim}$30 cm) at the coast and the fast westward propagation speeds (${\sim}$13 km/day) of the gyres. The coastal sea-level drop is enhanced by several factors: horizontal mixing, enhanced forcing, coastal geometry, and the existence of a second active layer in the 2$\frac{1}{2}$-layer model. Horizontal mixing enhances the sea-level drop because the coastal boundary layer is actually narrower with mixing. The forcing ${\tau}$/h is enhanced near the coast where h is thin. Especially, in analytic solutions to the 2$\frac{1}{2}$-layer model the presence of two baroclinic modes increases the sea-level drop to some degree. Of theses factors the strengthened forcing ${\tau}$/h has the largest effect on the magnitude of the drop, and when all of them are included the resulting maximum drop is -30.0 cm, close to observed values. To investigate the processes that influence the propagation speeds of anticyclonic gyre, several test wind-forced calculations were carried out. Solutions to dynamically simpler versions of the 1$\frac{1}{2}$-layer model show that the speed is increased both by ${\beta}$-induced self-advection and by larger h at the center ofthe gyres. Solutions to the 2$\frac{1}{2}$-layer model indicate that the lower-layer flow field advects the gyre westward and southward, significantly increasing their propagation speed. The Papagayo gyre propagates westward at a speed of 12.8 km/day, close to observed speeds.

• Journal of Trauma and Injury
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• v.35 no.1
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• pp.56-60
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• 2022

The most common cause of foot drop is lumbar degenerative disc herniation, particularly at L4/5. We present a rare case of spinal cord injury accompanied by a thoracolumbar lesion that presented with bilateral foot drop. A 69-year-old male patient presented with sudden-onset severe bilateral leg pain and bilateral foot drop. Radiologic findings revealed T12 spondylitis compressing the conus medullaris. He had undergone vertebroplasty for a T12 compression fracture after a fall 6 months before. A physical examination showed bilateral foot drop, paresthesia of both L5 dermatomes, increased deep tendon reflex, and a positive Babinski sign. An acute bilateral L5 root lesion and a conus medullaris lesion were suspected based on electromyography. A surgical procedure was done for decompression and reconstruction. After the operation, bilateral lower extremity muscle strength recovered to a good grade from the trace grade, and the patient could walk without a cane. The current case is a very rare report of bilateral foot drop associated with T12 infectious spondylitis after vertebroplasty. It is essential to keep in mind that lesions of the thoracolumbar junction can cause atypical neurological symptoms. Furthermore, understanding the conus medullaris and nerve root anatomy at the T12-L1 level will be helpful for treating patients with atypical neurological symptoms.

• Corrosion Science and Technology
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• v.9 no.4
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• pp.171-174
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• 2010

MAO (micro-arc oxidation) is an eco-friendly convenient and effective technology to deposit high-quality oxide coatings on the surfaces of Ti, Al, Mg and their alloys. The roles of the electrolyte concentration and relative cathode electrode area sizes in the grown oxide film during titanium MAO were investigated. The higher the concentration of the electrolyte, the lower the $R_{total}A$ value. The oxide film produced by the lower concentration of the electrolyte is thinner and less uniform than the film by the higher concentration, which is thick and porous. The cathode area size must be bigger than the anode area size in order to minimize the voltage drop across the cathode. The ratio of the cathode area size to the anode area size must be bigger than 8. Otherwise, the cathode will be another source for voltage drop, which is detrimental to and slows down the oxide growth.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.1
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• pp.31-40
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• 2021

The main stability factors of the pressed powder include hardness and drop stability. In general, for pressed powder with talc, the hardness and drop stability are evenly met and the skin texture is excellent. Recently, more than ever customers are looking for a replacement due to asbestos issue of talc. Therefore, it is urgent to develop a pressed powder formulation without talc that maintains stability and does not lose its sense of use. In this study, experiments were conducted to find the optimal ingredients mixing ratio to make talc-free pressed powder. The characteristics of raw materials used mainly in powder were checked and the ratio was changed, and the lightness and hardness were measured and drop test was conducted. If the natural mica ratio was higher than the synthetic mica or non-coated silica was used instead of the coated silica, the hardness and drop stability were lower than the content containing talc, but the lightness was similar. Conversely, if the synthetic mica ratio was equal to or higher than the natural mica ratio and the coated silica ratio was equal to or higher than the non-coated silica ratio, the hardness and drop stability of the content containing talc were similar, but the lightness was low. It was found that the hardness was higher than the content containing talc, but the drop stability was lower. Therefore, further study of the correlation between hardness and fall stability is also thought to be necessary.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.51-57
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• 2014

The purpose of this study was to compare and analyze kinetic variables of lower limbs according to types of ankle taping in drop landing. For this, targeting seven male basketball players (average age: $20.8{\pm}0.74yrs$, average height: $187.4{\pm}3.92cm$, average weight: $79.8{\pm}7.62kg$) with no instability of ankle joints, the drop landing motion was conducted according to three types of inelastic taping (C-type), elastic taping (K-type), and no treatment (N-taping). Based on the result, the next conclusion was reached. First, the effect of taping for the players with stable ankles was minimal and the high load on ankle joints offset the fixing effect of inelastic taping. Thus the inelastic taping for the players with stable ankles did not have an effect on the control of dorsal flexion during one-foot landing. Second, increasing angular velocity by increasing the movable range of knee joints disperses impact forces, yet inelastic taping restricted the range of knee joint motion and at the same time increased angular velocity, adding to a negative effect on knee joints. Third, inelastic taping induced inefficient motion of Lower limbs and unstable impact force control of ankle joints at the moment of landing and produced maximum vertical ground reaction force, which led to an increase of load. Therefore, inelastic ankle taping of players whose jump actions occur very often should be reconsidered. Also, it is thought that this study has a great meaning in proving the problem of inelastic taping related to knee pain with unknown causes.

• The Korean Fashion and Textile Research Journal
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• v.17 no.2
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• pp.227-236
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• 2015

This study analyzed the lower body type of 30's Korean men to develop a slim-fit pants pattern. As the analysis data, direct measurement data of anthropometric measured value in the 6th Size Korea(KATS, 2010) was used as basic data with 481 men in 30's as analysis objects. The result are as follows. First, the result of analyzing factors for the lower body type classification indicated five factors. Second, the result of executing group analysis (with the independent variable of 5 clusters extracted from the factor analysis)classified the following three types. Type 1(36.8%) displayed a medium height of lower body type, small waist and hip, slim and fit body type with a slim shape between the knee and ankle. The shape between the waist and hip had characteristics of a slight curve and short length. Type 2(35.6%) displayed lowest height of a lower body type that was large and thick between the waist and the hip. The drop value of the waist and the hip was small; therefore, the body type was flat with a minimal curve. The underpart type (below the knee) was the thickest and the length was short. Type 3(27.7%) displayed the highest lower body type, a medium level waist size, flat and narrow waist and belly. This body type had a curve with big drop value of the waist and the hip, lower part from the hip to the ankle (including the knee) and a thick calf with along leg.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1807-1811
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• 2008

In this paper, the meniscus formation/deformation processes and conduction characteristics of the needle-centered ceramic nozzle electrode as an effective electrohydrodynamic (EHD) flow driving mechanisms for de-ionized water and silicone oil have been investigated. Results showed that the applied high voltage affected significantly on the processes, such as the drop formation mode, the deformation mode, the dripping mode, the jet mode, and the atomization mode. There was the EHD atomization mode for the de-ionized water while it was not occurred for the silicone oil, which, however, might be due to the lower electric conductivity and dielectric property of the oil than that of the water.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.6
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• pp.739-748
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• 2004

A hybrid dust-collector combining a fabric filter with centrifugal force was developed to enhance the performance of the conventional fabric filter systems and its performances were evaluated to compare to that of the existing dust collector. The pressure drop rapidly increased with increasing the elapsed time and the face velocity in two filtration systems. But the increasing ratio of a hybrid dust-collector compare to the existing dust collector was lower. This results were confirmed from the performance such as cleaning interval, residual pressure drop and dust loading rate. The overall collection efficiency of the hybrid dust-collector was more than 99.6% and this showed a improvement of 0.6～2% than that of the existing dust collector. Especially, the fractional collection efficiency at the particle size of around 1${\mu}{\textrm}{m}$ is about 4% higher than that of the existing dust collector.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.5
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• pp.506-513
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• 2007

One of the most widely used static mixers is Sulzer type mixer. However the structure of the element is so complicated that the mixing efficiency is better than others, whereas the pressure drop is larger than the others. Therefore new elements are necessary to reduce the pressure drop and to minimize the decrease of the mixing efficiency compared with the Sulzer ones. The objectives of this study are to develop new static mixer and to perform the experimental investigation in order to evaluate the performance of the new one, and to investigate the applicability of the one in an inline coagulant mixing system for water treatment, The pressure drops of the new static mixer elements were about 4-12% lower than that of the Sulzer SMX one, and the mixing efficiency of the Sulzer SMX one was about 2-5% higher than that of the new ones. The inline coagulant mixing system with a new static mixer element performed significantly better than the traditional mechanical mixing system for turbidity removal.

• International Journal of Air-Conditioning and Refrigeration
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• v.16 no.1
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• pp.9-14
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• 2008

In this study, pressure drop and heat transfer characteristics of plain finned heat exchangers having 5.0 mm diameter (fin collar 5.3 mm) tubes were investigated. Six samples having different fin pitches (1.1 to 1.3 mm) and tube rows (1 and 2 row) were tested. The fin pitch had a negligible effect on j and f factors. Both j and f factors decreased as the number of tube row increased, although the difference was not significant for the f factor. When compared with the j and f factors of the samples having 7.3 mm diameter tubes, the present j and f factors yielded lower values. However, the j/f ratio was larger at low Reynolds numbers. Possible reasoning is provided from the flow pattern consideration. Comparison with existing correlations were made.