• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.1
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• pp.125-131
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• 1997

The extinction of premixed flames under the influence of stretch is studied numerically. A wide range of fuel (hydrogen, ethylene, acetylene, methane, propane and methanol) and air mixtures are established in an opposed jet and their flame properties such as flame speed, flame thickness, thermal diffusivity, and stretch rate at extinction are computed. Computations are made using several chemical kinetic mechanism (Smooke, Kee et al. and Peters). The major result is that, in contrast to the various previous claims of extinction Karlovitz number varying over three orders of magnitude, it is found to be constant around two for all of the mixtures tested. That is, premixed flames are extinguished when the physical flow time decreases (due to increased stretch rate) to the point where it approximately equals the chemical reaction time. Here the relevant chemical reaction time is not the one computed using the one-dimensional flame properties as originally suggested in the formulation of Karlovitz number, but rather it is the one obtained using the stretched flame properties which fully reflect the effect of straining on the flame structure.

• Journal of Korean Foot and Ankle Society
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• v.8 no.2
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• pp.204-207
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• 2004

An unstable second metatarsophalangeal joint may produce pain in the forefoot. Plication of stretched lateral ligament and capsule and transfer of the extensor digitorum brevis under the transverse intermetatarsal ligament performed as the primary procedure to stabilize this painful joint. But the pain was not subsided and the proximal phalanx was resubluxated. So, we osteotomized the second metatarsal to restore a normal alignment of the second toe. Then the symptom was subsided. We report a case of painful instability of the metatarsophalangeal joint of the second toe.

• Journal of Korean Neurosurgical Society
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• v.56 no.6
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• pp.531-533
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• 2014

We present a case of angiographically confirmed transection of the cisternal segment of the anterior choroidal artery (AChA) associated with a severe head trauma in a 15-year old boy. The initial brain computed tomography scan revealed a diffuse subarachnoid hemorrhage (SAH) and pneumocephalus with multiple skull fractures. Subsequent cerebral angiography clearly demonstrated a complete transection of the AChA at its origin with a massive extravasation of contrast medium as a jet trajectory creating a plume. We speculate that severe blunt traumatic force stretched and tore the left AChA between the internal carotid artery and the optic tract. In a simulation of the patient's brain using a fresh-frozen male cadaver, the AChA is shown to be vulnerable to stretching injury as the ipsilateral optic tract is retracted. We conclude that the arterial injury like an AChA rupture should be considered in the differential diagnosis of severe traumatic SAH.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.314-318
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• 2006

This study is to analyze the intensity of welding part by simulating the dynamic procedure during the fracture of plates with spot welding. The upper and tower plates attached with spot welding can be seen to fall apart at the elapsed time of 0.64 ms after the upper plate is stretched from the lower plate. The maximum von Mises stress is shown at the welding part in the mid of upper and lower plates. The internal energy decreases largely and the kinetic energy increases suddenly near the elapsed time of 0.64 ms when welding part breaks down. The sliding energy decreases with step-by-step style as the time elapses. The value of this energy becomes 0 at the elapsed time of 0.2 ms and on the contrary, two plates stick each other as this value becomes a minus after this time.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.961-965
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• 1992

It is well-known that shock waves frequently occur inside the nozzle of the interrupter, and that they play important roles in the arc interruption. A model interrupter with two-dimensional dual-airflow nozzles was used for this experiment. The arc was ignited with 1.4 mil copper wire stretched between the electrodes which were spaced out 56 mm. The arc current of 60 to 230 A was achieved by adjusting the external resistance from 5.5 to 1.6 ohms. The arc tests have been conducted for investigating the air arc characteristics, and the effects of shock waves and nozzle pressure ratios on the arc voltage, the arc resistance, the arc power, and average electric field. The results of these tests have been analyzed to provide insights into the arc characteristics for gas circuit breakers. The average electric field is represented by the function of the arc current to show the negative E-I characteristic explicitly. The effects of shock waves and nozzle pressure ratios are shown to be significant for a circuit breaker performance.

• Journal of Microbiology and Biotechnology
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• v.30 no.6
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• pp.830-838
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• 2020

The histone-like nucleoid structuring protein (H-NS) is an abundant global regulator of environmentally controlled gene expression. Herein, we demonstrate that H-NS represses the expression of LeuO, the master regulator of the cyclic(Phe-Pro)-dependent signaling pathway, by directly binding to the upstream region of the gene. H-NS binds to a long stretched region (more than 160-bp long), which overlaps with binding sites for ToxR and LeuO. A high quantity of H-NS outcompetes ToxR for binding to the cis-acting element of leuO. However, our footprinting analyses suggests that the binding of H-NS is relatively weaker than LeuO or ToxR at the same molarity. Considering that the DNA nucleotide sequences of the upstream regions of leuO genes are highly conserved among various Vibrio, such patterns as those found in V. vulnificus would be a common feature in the regulation of leuO gene expression in Vibrionaceae. Taken together, these results suggest that, in species belonging to Vibrionaceae, H-NS regulates the expression of leuO as a basal stopper when cFP-ToxR mediated signaling is absent.

• Journal of Biomedical Engineering Research
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• v.26 no.2
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• pp.111-116
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• 2005

This study was designed to apply the stimulation system developed in our laboratory to investigate how the stimulation conditions affect the muscle contractile characteristics in the isometric condition as well as during the FES standing/walking. Four paraplegic and ten healthy subjects participated in this study, and their knee extensors were voluntary contracted or electrically stimulated to measure the muscle force and the fatigue index for different waveforms of the pulse train. We also investigated different combinations of the electrode positions during standing/walking. It was confirmed that continuous and high-frequency stimulation causes faster fatigue than intermittent and low-frequency stimulation. Fatigue resistance was higher around the optimal muscle length than at a stretched position in healthy subjects, whereas the opposite was observed in paralyzed subjects. The paired t-test results with the level of significance at 0.01 indicated that the sinusoidal waveform generated the largest torque among the four typical waveforms. Although statistically not very significant, the sinusoidal waveform also generated, in general, the highest fatigue resistance at an intensity level below the supramaximal stimulation. One of the paraplegic subject who participated in the standing/walking program can now stand up for 1 minute and 50 seconds with the knee extensors, and walk for about 5 minutes at the speed of 12m/sec.

• Journal of the Korean Society of Food Culture
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• v.15 no.4
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• pp.307-312
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• 2000

The purpose of this study is to understand the Chinese noodles(mian tiao). Wheat seems to have been cultivated 3-4,000 years before according to the archaeological evidences from the neolithic sites. The five grains(rice, millet, beans, barley, barnyard millet) already appeared in the period prior to Chin dynasty and were used as whole grain, but it was not until Chun Chu Zhan Guo period that the introduction of the flouring method stimulated the cultivation of wheat. In Chin-Han period, when water power and animal force were put into usage to facilitate the mass production of wheat flour, 'Bing', a designation for all the food made of wheat first appeared in the literature, and it was this 'Bing' that had later developed into noodles. In Wei Chin Nan Bei Chao period, roasted 'Bing', namely 'Kao-Bing' made its first appearance, and in Tang period, various noodles were created with the increase of restaurants specialized in noodles. In Song dynasty, 'La-Mian', the noodles stretched and beat from noodle dough, was first introduced, and in Yuan period, invention of drying method made the appearance of dried noodles, 'Gua-Mian', possible, which was good for easy and long preservation. Qing dynasty developed the noodles with a variety of assorted ingredients. The Chinese noodles are classified by various standards such as main ingredients, cooking methods, kinds of sauce, secondary ingredients, shape, eating method, flavor, and look.

• Korean Journal of Geomatics
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• v.3 no.1
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• pp.59-65
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• 2003

The merging of different scales or multi-sensor image data is becoming a widely used procedure of the complementary nature of various data sets. Ideally, the merging method should not distort the characteristics of the high-spatial and high-spectral resolution data used. To present an effective merging method for survey of reclaimed land using the high-resolution (6.6 m) Electro-Optical Camera (EOC) panchromatic image of the first Korea Multi-Purpose Satellite 1 (KOMPSA T-l) and the multispectral Moderate Resolution Imaging Spectroradiometer (MODIS) image data, this paper compares the results of Intensity Hue Saturation (IHS) and Principal Component Analysis (PCA) methods. The comparison is made by statistical and visual evaluation of three-color combination images of IHS and PCA results based on spatial and spectral characteristics. The use of MODIS bands 1, 2, and 3 with a contrast stretched EOC panchromatic image as a substitute for intensity was found to be particularly effective in this study.

• Structural Monitoring and Maintenance
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• v.7 no.3
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• pp.233-259
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• 2020

Using bonded fiber-reinforced polymer laminates for strengthening wooden structural members has been shown to be an effective and economical method. In this research, properties of suitable composite materials (sika wrap), adhesives and two ways of strengthening beams exposed to bending moment are presented. Passive or slack reinforcement is one way of strengthening. The most effective way of such a strengthening was to place reinforcement laminates in the stretched part of the wooden beam (lower part in our case), in order to investigate the effectiveness of externally bonding FRP to their soffits. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, i.e., the wooden beam, the sika wrap composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions. This research is helpful for the understanding on mechanical behaviour of the interface and design of the composite-wooden hybrid structures. The results showed that the use of the new strengthening system enhances the performance of the wooden beam when compared with the traditional strengthening system.