• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.39-43
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• 2008

Purpose: There are various methods to diagnose hemangioma, such as ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI) and nuclear medicine. However, by development of SPECT imaging, the blood-pool scan using $^{99m}Tc$-labeled red blood cell has been used, because it was non-invasive and the most economical method. Therefore, in this study, we proposed that the usefulness of $^{99m}Tc$-RBC scan and SPECT of the head and neck to diagnose unlocated hemangiomas. Materials and Methods: $^{99m}Tc$-RBC scan and SPECT was performed on 6 patients with doubtful hemangioma (4 person, head; 1 person, neck; 1 person, another). We labeled radiopharmaceutical using modified in vivo method and then, centrifuged it to remove plasma. After a bolus injection of tracer, dynamic perfusion flow images were acquired. Then, anterior, posterior, both lateral static blood-pool images were obtained as early and 4 hours delayed. SPECT was progressed 64 projections per 30 seconds. Each image was interpreted by physicians, Nuclear medicine specialist, and technologist blinded to patient's data. Results: In 5 patients of all the radioactivity of doubtful site didn't change in flow images, but, in blood-pool, delayed and SPECT images, it was increased. So, it was a typical hemangioma finding. The size of lesion was over 2 cm, and it could discriminate as comparing to the delayed and SPECT imaging. On the other hand, in 1 patient, the radioactivity was increased in blood-pool images, but, not in delayed and SPECT images, so, it was proved no hemangioma. Conclusion: Using $^{99m}Tc$-RBC Scan and SPECT, we could diagnose the hemangiomas in head and neck, as well as, liver, more non-invasive, economical, and easy. Therefore, it considered that $^{99m}Tc$-RBC scan and SPECT would offer more useful information for diagnosis of hemangioma, rather than otherimaging such as US, CT, MRI.

• 한국지구물리탐사학회:학술대회논문집
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• 2002.09a
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• pp.139-162
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• 2002

Since weak zones or geological lineaments are likely to be eroded, weak zones may develop beneath rivers, and a careful evaluation of ground condition is important to construct structures passing through a river. Dc resistivity surveys, however, have seldomly applied to the investigation of water-covered area, possibly because of difficulties in data aquisition and interpretation. The data aquisition having high quality may be the most important factor, and is more difficult than that in land survey, due to the water layer overlying the underground structure to be imaged. Through the numerical modeling and the analysis of case histories, we studied the method of resistivity survey at the water-covered area, starting from the characteristics of measured data, via data acquisition method, to the interpretation method. We unfolded our discussion according to the installed locations of electrodes, ie., floating them on the water surface, and installing at the water bottom, since the methods of data acquisition and interpretation vary depending on the electrode location. Through this study, we could confirm that the dc resistivity method can provide the fairly reasonable subsurface images. It was also shown that installing electrodes at the water bottom can give the subsurface image with much higher resolution than floating them on the water surface. Since the data acquired at the water-covered area have much lower sensitivity to the underground structure than those at the land, and can be contaminated by the higher noise, such as streaming potential, it would be very important to select the acquisition method and electrode array being able to provide the higher signal-to-noise ratio data as well as the high resolving power. The method installing electrodes at the water bottom is suitable to the detailed survey because of much higher resolving power, whereas the method floating them, especially streamer dc resistivity survey, is to the reconnaissance survey owing of very high speed of field work.

• Journal of Korean Neurosurgical Society
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• v.63 no.1
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• pp.89-98
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• 2020

Objective : Ossification of posterior longitudinal ligament (OPLL) in the thoracic spine may cause chronic compressive myelopathy that is usually progressive, and unfavorable by conservative treatment. Although surgical intervention is often needed, the standard surgical method has not been established. Recently, it has been reported that posterior decompression with dekyphosis is effective surgical technique for favorable clinical outcome. The purpose of this study was to evaluate the surgical outcomes in patients with thoracic OPLL according to dekyphosis procedure and to identify predictive factors for the surgical results. Methods : A total of 25 patients with thoracic OPLL who underwent surgery for myelopathy from May 2004 to March 2017, were retrospectively reviewed. Patients with cervical myelopathy were excluded. We assessed the clinical outcomes according to various surgical approaches. The modified Japanese orthopedic association (JOA) scores for the thoracic spine (total, 11 points) and JOA recovery rates were used for investigating surgical outcomes. Results : Of the 25 patients, 10 patients were male and the others were female. The mean JOA score was 6.7±2.3 points preoperatively and 8.8±1.8 points postoperatively, yielding a mean recovery rate of 53.8±31.0%. The mean patients' age at surgery was 52.4 years and mean follow-up period was 40.2 months. According to surgical approaches, seven patients underwent anterior approaches, 13 patients underwent posterior approaches, five patients underwent combined approaches. There was no significant difference of the surgical outcomes related with different surgical approaches. Age (≥55 years) and high signal intensity on preoperative magnetic resonance (MR) image in the thoracic spine were significant predictors of the lower recovery rate after surgery (p<0.05). Posterior decompression with dekyphosis procedure was related to the excellent surgical outcomes (p=0.047). Dekyphosis did not affect the complication rates. Conclusion : In this study, our result elucidated that old age (≥55 years) and presence of intramedullary high signal intensity on preoperative MR images were risk factors related to poor surgical outcomes. In the meanwhile, posterior decompression with dekyphosis affected favorable clinical outcome. Posterior approach with dekyphosis procedure can be a recommendable surgical option for favorable results.

• Geophysics and Geophysical Exploration
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• v.2 no.1
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• pp.8-16
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• 1999

In terms of high resolution, seismic reflection survey is by far the most significant geophysical method applied to define subsurface structure. In shallow seismic reflection survey, it is, however, difficult to obtain high resolution image due to both the wave attenuation in the unconsolidated layer and the existence of source-generated surface waves Therefore, when collecting data, it is imperative to select proper equipments and choose optimum field data acquisition parameters for acquiring high S/N data. In this survey, a small size hammer was used as a low energy source and 40-Hz vertical geophones were used as receivers. Trigger signal was obtained from the hammer starter attached in the aluminum plate and thus it was possible to control the source onset time for the vertical stack. During the field work, a modified standard CMP technique was introduced to achieve the many-fold CMP data effectively. Data processing was conducted by the 'Seismic Unix' which is mounted on PC with a Linux operating system. The main distinctions were the emphasis and detail placed on near-surface velocity analysis and the extra care exercised in muting.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.993-994
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• 2008

Electrochromic (EC) devices are capable of reversibly changing their optical properties upon charge injection and extraction induced by the external voltage. The characteristics of the EC device, such as low power consumption, high coloration efficiency, and memory effects under open circuit status, make them suitable for use in a variety of applications including smart windows and electronic papers. Coloration due to reduction or oxidation of redox chromophores can be used for EC devices (e-paper), but the switching time is slow (second level). Recently, with increasing demand for the low cost, lightweight flat panel display with paper-like readability (electronic paper), an EC display technology based on dye-modified $TiO_2$ nanoparticle electrode was developed. A well known organic dye molecule, viologen, was adsorbed on the surface of a mesoporous $TiO_2$ nanoparticle film to form the EC electrode. On the other hand, ZnO is a wide bandgap II-VI semiconductor which has been applied in many fields such as UV lasers, field effect transistors and transparent conductors. The bandgap of the bulk ZnO is about 3.37 eV, which is close to that of the $TiO_2$ (3.4 eV). As a traditional transparent conductor, ZnO has excellent electron transport properties, even in ZnO nanoparticle films. In the past few years, one-dimension (1D) nanostructures of ZnO have attracted extensive research interest. In particular, 1D ZnO nanowires renders much better electron transportation capability by providing a direct conduction path for electron transport and greatly reducing the number of grain boundaries. These unique advantages make ZnO nanowires a promising matrix electrode for EC dye molecule loading. ZnO nanowires grow vertically from the substrate and form a dense array (Fig. 1). The ZnO nanowires show regular hexagonal cross section and the average diameter of the ZnO nanowires is about 100 nm. The cross-section image of the ZnO nanowires array (Fig. 1) indicates that the length of the ZnO nanowires is about $6\;{\mu}m$. From one on/off cycle of the ZnO EC cell (Fig. 2). We can see that, the switching time of a ZnO nanowire electrode EC cell with an active area of $1\;{\times}\;1\;cm^2$ is 170 ms and 142 ms for coloration and bleaching, respectively. The coloration and bleaching time is faster compared to the $TiO_2$ mesoporous EC devices with both coloration and bleaching time of about 250 ms for a device with an active area of $2.5\;cm^2$. With further optimization, it is possible that the response time can reach ten(s) of millisecond, i.e. capable of displaying video. Fig. 3 shows a prototype with two different transmittance states. It can be seen that good contrast was obtained. The retention was at least a few hours for these prototypes. Being an oxide, ZnO is oxidation resistant, i.e. it is more durable for field emission cathode. ZnO nanotetropods were also applied to realize the first prototype triode field emission device, making use of scattered surface-conduction electrons for field emission (Fig. 4). The device has a high efficiency (field emitted electron to total electron ratio) of about 60%. With this high efficiency, we were able to fabricate some prototype displays (Fig. 5 showing some alphanumerical symbols). ZnO tetrapods have four legs, which guarantees that there is one leg always pointing upward, even using screen printing method to fabricate the cathode.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.3
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• pp.136-146
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• 2013

This study has specified terminology for mountain ridgeline, and organized the present condition of Korean mountain ridgeline and empirical management measures of Beakdudeagan and Jeongmeak. Moreover, based on previously published paper maps, mountain map, and numerical maps, this study has used GIS to reorganize Jeongmaek of Korea, including Hanbukjeongmaek, Hannamjeongmaek, and Gumbukjoengmaek. To ensure accuracy, DEM, Shaded Relief Image, gradient, curvature, and aspect have been analyzed from recent numerical maps. On extraction process, this study analyzes more specifically the results, previous Beakdudaegan is modified and new Jeongmaeks have been extracted. Moreover, for analyzing natural environment of surrounding of major mountain ridgeline, ecological zoning grade of mountain ridgeline is analyzed. With the analyzed result, domestic and foreign mountain ridgeline management policy is suggested, and environmental impact assessment method for major mountain ridgeline development is also suggested. In this study, Baekdudaegan and its Jeongmaek are organized and analyzed. With the results, this study suggested political linkage of mountain ridgelines and guidelines for environmental impact assessment of ridgeline development.

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.145-150
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• 2008

In this work we have studied the antifouling properties of the hydrophobic sol-gel modified sensing membrane and its optical properties for sensor application. E. coli JM109, B. cereus 318 and P. pastoris X-33 were cultivated in confocal cultivation dishes with glass surface, respectively. The glass surface was coated with the hydrophobic sol-gels prepared by the dimethoxy-dimethyl-silane (DiMe-DMOS) and tetramethyl-orthosilicate (TMOS). After cultivation, microorganisms adhered on the surface coated with sol-gels and glass surface were dyed by gram-staining method and the numbers of microorganisms were analyzed based on the image data of the scanning electronic microscope (SEM). A great number of microorganisms, about $2{\sim}3{\times}10^4/mm^2$, was adhered on the glass surfaces which no hydrophobic sol-gels were coated. But, the antifouling effect of the hydrophobic sol-gels was large, that microorganisms of less than $200{\sim}300/mm^2$ were adhered on the coated glass surface. The performance of the sensing membranes for detection of pH and dissolved oxygen was enhanced by recoating the light insulation layer prepared with the mixture of the hydrophobic sol-gel and graphite particles.

• Composites Research
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• v.26 no.3
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• pp.175-181
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• 2013

The evaluation and prediction for the absorbed energy, residual velocity, and impact damage are the key things to characterize the impact behavior of composite laminated panel subjected to high-velocity impact. In this paper, the method to predict the residual velocity and the absorbed energy of Carbon/Epoxy laminated panel subjected to high velocity impact are proposed and examined by using quasi-static perforation test and high-velocity impact test. Total absorbed energy of specimen due to the high-velocity impact can be grouped with static energy and kinetic energy. The static energy are consisted of energy due to the failure of the fiber and matrix and static elastic energy, which are related to the quasi-static perforation energy. The kinetic energy are consisted of kinetic energy of moving part of specimen, which are modelled by three modified kinetic model. The high-velocity impact test were conducted by using air gun impact facility and compared with the predicted values. The damage area of specimen were examined by C-scan image. In the high initial impact velocity above the ballistic limit, both the static energy and the kinetic energy are known to be the major contribution of the total absorbed energy.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.3
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• pp.260-272
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• 2001

All-ceramic restorations have had a more limited life expectancy than metal ceramic restorations because of their low strength. Their relatively lower strength and resistance to fracture have restricted the use of all-ceramic crowns to anterior applications where occlusal loads are lower. But there has been increasing interest in all-ceramic restorations because patients are primarily concerned with improved esthetics. Many efforts have been made to in prove the mechanical properties of dental ceramics. This study was designed to elucidate the influence of the luting agent on the strength of the Empress 2 crown (staining technique) cemented on human teeth. Seventy extracted human permanent molar teeth were chosen. Teeth were prepared for Empress 2 crowns with milling machine on a surveyor. A dental bur was placed in the mandrel that was positioned so that the long axis of the bur was perpendicular to the surveyor base. Dimensions of the Empress 2 crown preparation were $6^{\circ}$ taper on each side, $1.5{\pm}0.1mm$ shoulder margin, and 4mm crown height. The luting cements used in this study were as follow: 1. Uncemented 2. Zinc phosphate cements (Confi-Dental) 3. Conventional glass ionomer cement : Fuji 1 (GC) 4. Resin-modified glass ionomer cements : Fuji plus (GC) 5. Adhesive cements : Panavia F (Kuralay), Variolink II (Vivadent), Choice (Bisco). Fracture test using Instron. The crowns were loaded in compressive force to evaluate the effect of these cements on the breaking strength of these all-ceramic crowns. A steel ball with a diameter of 4mm was placed on the occlusal surface and load was applied to the steel ball by a cylindrical bolt with a crosshead speed of 0.5mm per minute until fracture occurred. The fractured surface was examined using Scanning Electron Microscopic Image (SEM) to discover the correlation between fracture strength and bonding capacity. Within the limitation of this in vitro study design, the results were as follows : 1. fomentations significantly increased the fracture resistance of Empress ceramic crowns compared to control. Uncemented (206.9 N): ZPC (812.9 N): Fuji 1 (879.5 N): Fuji Plus (937.7 N): Choice (1105.4 N): Variolink II (1221.1 N): Panavia F (1445.2 N). 2. Resin luting agent, treated by a silane bond enhancing agents, yielded a significant increase in fracture resistance. In some of the Panavia F group, a fracture extended into dentin. 3. According to SEM images of fractured Empress crowns, the stronger the bond at both interfaces(crown and die), the more fracture strength was acquired.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.2
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• pp.369-377
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• 2008

Though the Hough transform(HT) is a well-known method for detecting analytical shape represented by a number of free parameters, the basic property of the HT, the one-to-many mapping from an image spare to a Hough space, causes the innate problem, the sensitivity to noise. This basic problem also deteriorates the quality of detected lines and makes the detected line deviated from the real one or generates some bogus, multiple lines where only one real line exists. The size of Hough space also affects the quality of detected lines. In this paper, we analyzed the line distortions in the traditional Hough transform and showed that the distortions are relieved in the edge strength Hough transform(ESHT), which is a modified HT. However the usage of expanded edge and edge strength in ESHT can cause some new line distortions which do not exist in the HT. These new ones can be solved by a proper setting of decreasing and broadening parameter values and the optimal values can be determined only by some pre-determined values. We also illustrated several examples to show the distortion-decreasing property of ESHT.