• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.315-333
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• 1990

This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography (l4 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator(60㎜ in diameter, 20㎝ in length) and rectangular collimator(35㎜ × 44㎜, 40㎝ in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rates of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling techniuqe, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.415-426
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• 2010

Post-grouting for the drilled shaft is known to increase the end bearing capacity of pile 2~3 times higher by consolidating and reinforcing the disturbed ground containing slime around the pile end. However, the general design guideline for post-grouting has not been established yet in Korea. Especially in the domestic application, the post-grouting is employed just for repairing the pile with the unacceptable resistance rather than for increasing the design resistance of pile. Therefore, little is reported about the effect of post-grouting on the pile resistance itself. In this study, the effect of post-grouting on the resistance of drilled shafts installed in the weathered rock in Korea was estimated by performing the bi-directional load tests on the piles with and without the post-grouting. The test results presented that the initial slope of end bearing-base displacement curve in the pile with post-grouting was 4 times higher than that without post-grouting. At the acceptable settlement (1% of pile diameter), the end bearing capacities of piles with and without the post-grouting were estimated to be 12.0 MPa and 7.0 MPa, respectively, indicating that the post-grouting could increase the end bearing resistance of pile in weathered rock more than 70%.

• Journal of the Korean Institute of Gas
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• v.2 no.4
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• pp.25-33
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• 1998

The characteristics of evaporation heat transfer for the utilization of LNG cold energy was investigated experimentally using liquified nitrogen and a solution of ethylene-glycol and water under horizontal two-phase conditions in the small-scale equipment of a cryogenic heat exchange system. The inner tubes in the double pipe heat exchanger with 8 mm and 15 mm inner diameter and 6 m length were adopted as a smooth test tubes and enhanced tubes by means of wire-coil inserts. Heat transfer coefficients and Nusselt number for the test tube were calculated from measurements of temperatures, flowrates and pressures. The correlations in a power-law relationship of the Nusselt number, the Reynolds number and Prandtl number for heat transfer were proposed which can be available for design of cryogenic heat exchangers. The correlations showed heat transfer coefficients for the wire-coil inserts were much higher than those for the smooth tubes, increased by more than 2.5 ${\~}$ 5.5 times depending upon the equivalent Reynolds number. Form and length of cryogenic double pipe heat exchanger were proposed for applicable to the utilization of LNG cold energy.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.6
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• pp.699-706
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• 2007

The cooling heat transfer coefficient and pressure drop of $CO_2$(R-744) in helical coil copper tubes were investigated experimentally The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter. a pre-heater and a inclined helical coil type gas cooler (test section). The test section consists of a smooth copper tube of 2.45 and 4.55mm inner diameter The refrigerant mass fluxes were varied from 200 to $600 [kg/m^2s]$ and the inlet pressures of 9as cooler were 7.5 to 10.0 [MPa]. The heat transfer coefficients of $CO_2$ in helical coil tubes increase with the increase of mass flux and gas cooling pressure of $CO_2$. The pressure drop of $CO_2$ in the gas cooler shows a relatively food agreement with those Predicted by Ito's correlation developed for single-phase in helical coil tubes. Though a few correlation available with the data. the local heat transfer coefficient of $CO_2$ agrees well with those presented by Pitla et al. among the predictions. However at the region near pseudo-critical temperature. the experiment data indicate higher values than the Pitla et al. correlation.

• The Journal of Korean Medicine
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• v.35 no.1
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• pp.1-9
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• 2014

Objectives: This study was to propose a standardized method of retention enema by extracting elements associated with published experimental methods of retention enema. Methods: 1) Literature search (1) Data sources: Retrieval was made, using 'Enema' or 'Retention Enema' as search words in Medline, Cochrane library, KISS, RISS, and KDSL DB. (2) Study selection: Two authors excluded irrelevant papers and chose qualified abstracts from the rest of the papers. The chosen studies were reviewed fully by the authors so that they could screen the significant papers based on the exclusion criteria. (3) Data extraction: Data on the total number of subjects, the target disease, the animal species, the type, quality, length, and diameter of catheter, the insertion length of catheter, the sample, the sample volume, the process of retention enema and the number of retention enemas performed were extracted from the selected studies. 2) Performing preliminary experiments about the elements associated with experimental methods of retention enema. Results & Conclusions: The standardized experimental method is as follows: animal: 280-320g SD rat 1) inserting a rectal tube of 8 Fr that measures 8 cm into the animal's anus, 2) injecting herbal medicines at the volume of 6ml and 3) holding them for 10 minutes.

• Parasites, Hosts and Diseases
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• v.51 no.5
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• pp.569-572
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• 2013

Dirofilariasis is a rare disease in humans. We report here a case of a 48-year-old male who was diagnosed with pulmonary dirofilariasis in Korea. On chest radiographs, a coin lesion of 1 cm in diameter was shown. Although it looked like a benign inflammatory nodule, malignancy could not be excluded. So, the nodule was resected by video-assisted thoracic surgery. Pathologically, chronic granulomatous inflammation composed of coagulation necrosis with rim of fibrous tissues and granulations was seen. In the center of the necrotic nodules, a degenerating parasitic organism was found. The parasite had prominent internal cuticular ridges and thick cuticle, a well-developed muscle layer, an intestinal tube, and uterine tubules. The parasite was diagnosed as an immature female worm of Dirofilaria immitis. This is the second reported case of human pulmonary dirofilariasis in Korea.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1971-1972
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• 2008

Cardiopulmonary resuscitation(CPR) is an important clinical technique performing artificial ventilation and chest compression on a patient under emergent situation before arriving in hospital. Since the quality of CPR significantly affects the survival rate, it would be of great advantage to monitor respiration in real time during CPR. However, currently applied respiratory air flow transducers are difficult to apply with sensing elements in the middle of the flow axis. The present study developed a new turbulent air flow transducer conveniently applicable to CPR. Abrupt changes in diameter of the flow tube generated turbulence in air flow, thereby pressure difference was obtained to estimate the air flow rate, with no physical object on the flow plane. Expiration and inspiration were separated by the direction of the pressure difference, resulting in good symmetry. Pressure-flow relationship was tested on a quadratic model, which provided accurate enough estimation results. Therefore, the present turbulent air flow transducer seemed appropriate to monitor respiration during CPR.

• Journal of the Korean Society of Safety
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• v.33 no.1
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• pp.22-27
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• 2018

Many electronic devices are powered by various rechargeable batteries such as lithium-ion recently, and occasionally the batteries undergo thermal runaway and cause fire, explosion, and other hazards. If a battery fire should occur in an electronic device of vehicle and aircraft cabin, it is important to quickly extinguish the fire and cool the batteries to minimize safety risks. Attempts to minimize these risks have been carried out by many researchers but the results have been still unsatisfied. Because most rechargeable batteries are operated on the ion state during charge and discharge of electricity and the combustion of ion state has big difference with normal combustion. Here we focused on the effect of ions including an electron during combustion process. The effects of an ionized fuel on the flame stability and the combustion products were experimentally investigated in the propane jet diffusion flames. The burner used in this experiment consisted of 7.5 mm diameter tube for fuel and the propane was ionized with th ionizer (SUNJE, SPN-11). The results show that toe overall flame stability and shape such as flame length has no significant difference even in the higher ion concentration. However the fuel ionization affects to the pollutant emissions such as NOx and soot. NOx and CO emissions measured in post flame region decreased by fuel ionization, especially high fuel velocity, i.e. high ion density. TGA analysis and morphology of soot by TEM indicates that the fuel ionization makes soot to be matured.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.1
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• pp.39-49
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• 1995

This study was performed to determine the each location of lesions in the maxillary sinus and to evaluate the relationship between the floor of the antrum and the apical regions of teeth by the comparison of the panoramic view and panoramic sinus view. For this study, experimentally with two dry skulls, jelly balls of 8mm and 15mm in diameter containing a short wire for the radiopacity similar to the cyst and clinically 5 patients having mucosal cyst in the antrum and 10 patients having periapical lesion of molar were used. The experimental cystic lesions were simulated with jelly ball being attached in turn to each wall of the antrum. The radiolucent periapical lesions of upper molars were formed by using round bur and the radiopaque periapical lesions were simulated by filling the former lesions with lead foil. Each panoramic view and each panoramic sinus view of the experimental lesions and patients were obtained by using panoramic machine and analyzed. The obtained results were as follows : 1. On the panoramic sinus view, the innominate line was approximately coincided with the most lateral portion of the antrum and the posterior wall appeared as the narrow area at the mesial side of the innominate line. The anterior wall occupied totally the mesial side of the innominate line, and the medial wall occupied the mesial half of the antrum. 2. In all cases of experimental cystic lesion attached to each wall of the antrum, the location of each lesion was able to be determined by applying Tube shift technic. 3. The palatal root and mesiobuccal root of the molar appeared as being transposed each other mesiolaterally on the panoramic and panoramic sinus views. 4. The panoramic sinus view was superior to the panoramic view in revealing the relationship between the floor of the antrum and the periapical lesion.

• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.179-188
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• 1989

The purpose of this study was to measure Micro vicker's hardness of 4 kinds of anterior Composite resins (Pyrofil light bond anterior, Lite-fil anterior, Photo clear fil anterior, Silux) and 6 kinds of posterior Composite resin (Pyrofil light bond posterior. Lite-fil posterior, Photo clear fil posterior, Occlusin posterior, Palfique light posterior, P-30, posterior) according to deference of depth and distance of light tip from surface of composite resin. Each composite resin was filled into Teflon tube of 5mm in diameter and 5mm in depth, celluloid matrix was covered and the light in accordance with each composite resin was irradiated in distance of zero millimeter and 1 cm from light tip to surface of composite resin for 30 seconds. Specimens were sectioned longitudinally with cutting device. Microvicker's hardness measurements ware made at the depth of surface, 1mm, 2mm, 3mm, 4mm and 5mm from the surface to deep portion. Vicker's hardness numbers were taken on each depth under 200gm load for 30 seconds with MVK-E. The following results were: 1. The highest hardness value was measured at 1 mm depth. Then the deeper the depth, the lesser the hardness was observed. 2. The hardness value of anterior composite resins is lower than one of posterior composite resins. 3. Hardness number of composite resin irradiated in distance of zero millimeter from surface of composite resin was higher than one of 1 cm from surface of composite resin. 4. The pattern of hardness change at varying depth was similar to all the experimental material with no relation to distance of light from specimen.