• Transactions of the Korean hydrogen and new energy society
• /
• v.22 no.1
• /
• pp.100-108
• /
• 2011

The use of biogas as an energy source reduces the chance of possible emission of two greenhouse gases, $CH_4$ and $CO_2$, into the atmosphere at the same time. Its nature of being a reproducible energy source makes its use even more attractive. This research if for the hydrogen production through the steam reforming of the biogas. The biogas utilized 3D-IR matrix burner in which the surface combustion is applied. The nickel catalyst was used inside a reformer. Parametric screening studies were achieved as Steam/Carbon ratio, biogas component ratio, Space velocity and Reformer temperature. When the condition of Steam/Carbon ratio, $CH_4/CO_2$ ratio, Space velocity and Refomer temperature were 3.25, 60%:40%, 19.32L/$g{\cdot}hr$ and $700^{\circ}C$ respectively, the hydrogen concentration and methane conversion rate were showed maximum values. Under the condition mentioned above, $H_2$ concentration was 73.9% and methane conversion rate was 98.9%.

• Imaging Science in Dentistry
• /
• v.32 no.3
• /
• pp.175-179
• /
• 2002

Follicular carcinomas are the second most common form of thyroid cancer, accounting for 10 to 20% of all thyroid cancers. Follicular carcinomas have a propensity to metastasize via the bloodstream, spreading to bone, lungs, liver, and elsewhere. We described the case of a 48-year-old woman who presented with swelling of the left preauricular area, which was a consequence of a metastatic follicular carcinoma of the masticator space. Plain films showed illdefined erosive bony changes from the left condylar head to the mandibular notch. Contrast-enhanced CT images showed a well circumscribed round mass with well enhancement within left masticator space. On MR images, the mass was heterogenously hyperintense to the muscle on T2-weighted images and isointense or hyperintense to the muscle on Tl-weighted images, and showed good enhancement on contrast-enhanced Tl-weighted images. Upon microscopic examination, the metastatic mass was found to be composed of fairly uniform cells forming small follicles containing colloid, showing capsular and vascular invasion.

• Journal of Astronomy and Space Sciences
• /
• v.31 no.1
• /
• pp.1-6
• /
• 2014

Quite recently, it has been suggested that the interaction of the solar wind with Mercury results in the variation in the solar wind velocity in the Earth's neighborhood during inferior conjunctions with Mercury. This suggestion has important implications both on the plasma physics of the interplanetary space and on the space weather forecast. In this study we have attempted to answer a question of whether the claim is properly tested. We confirm that there are indeed ups and downs in the profile of the solar wind velocity measured at the distance of 1 AU from the Sun. However, the characteristic attribute of the variation in the solar wind velocity during the inferior conjunctions with Mercury is found to be insensitive to the phase of the solar cycles, contrary to an earlier suggestion. We have found that the cases of the superior conjunctions with Mercury and of even randomly chosen data sets rather result in similar features. Cases of Venus are also examined, where it is found that the ups and downs with a period of ~ 10 to 15 days can be also seen. We conclude, therefore, that those variations in the solar wind velocity turn out to be a part of random fluctuations and have nothing to do with the relative position of inner planets. At least, one should conclude that the solar wind velocity is not a proper observable modulated by inner planets at the distance of 1 AU from the Sun in the Earth's neighborhood during inferior conjunctions.

• Journal of Electrochemical Science and Technology
• /
• v.4 no.1
• /
• pp.41-45
• /
• 2013

Platinum is a well known element which shows a significant electrocatalytic activity in many important applications. In glucose sensor, because of the poisoning effect of reaction intermediates and the low surface area, the electrocatalytic activity towards the glucose oxidation is low which cause the low sensitivity. So, we fabricate a nanoporous PtZn alloy electrode by deposition-dissolution method. It provides a high active surface and a large enzyme encapsulating space per unit area when it used for an enzymatic glucose sensor. Glucose oxidase was immobilized on the electrode surface by capping with PEDOT composite and PPDA. The composite and PPDA also can exclude the interference ion such as ascorbic acid and uric acid to improve the selectivity. The surface area was determined by cyclic voltametry method and the surface structure and the element were analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDX), respectively. The sensitivity is $13.5{\mu}A/mM\;cm^2$. It is a remarkable value with such simply prepared senor has high selectivity.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.7
• /
• pp.1036-1040
• /
• 2004

$Mn_{12}O_{12}(O_2CCH_2CH_2CH_2Cl)_{16}(H_2O)_4]$ (noted as $Mn_{12}$-BuCl), a new polynuclear complex of manganese chlorobutyrate has been successfully prepared by substitution of acetate with 4-chlorobutyric acid. The $Mn_{12}-BuCl$ crystallizes into triclinic space group P-1 with a = 14.5560(11) ${\AA}$, b = 14.5819(11) TEX>${\AA}$, c = 27.265(2) ${\AA}$, ${\alpha}\;=\;84.1140(10)^{\circ}\;,\;{\beta}\;=\;88.805(2)^{\circ},\;{\gamma}\;=\;89.8820(10)^{\circ}$, and Z = 2. The local environments of manganese 3+ and 4+ ions of the title compound are close to those of other $Mn_{12}$ compounds. The electrochemical data for $Mn_{12}-BuCl$ involve reversible reactions of two-electron reductions. The $Mn_{12}-BuCl$ also presents magnetic relaxation below 10 K implying that each molecule behaves as a single molecule magnet.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.35 no.4
• /
• pp.713-717
• /
• 2008

Albinism is a disease caused by partial or complete failure of melanin production in the skin, hair and eyes despite the presence of normal number, structure and distribution of melanocytes. Typical aspects are white-colored skin, blonde-brown hair, blue-brown irides and a prominent red reflex. Three main categories of albinism are oculocutaneous, ocular and localized albinism, and also they are divided into many subgroups. Therefore, appropriate treatment plan and dental direction would be differentiated according to them. This case report was about oral conditions and treatment of the oculocutaneous albinism patient with mental retardation who was refered due to developmental delay of teeth and treated with teeth extraction, restoration and space maintenance etc.

• Journal of Navigation and Port Research
• /
• v.42 no.6
• /
• pp.518-528
• /
• 2018

Unlike in the past, port space in modern society not only serves to meet port functions but also other functions such as housing, leisure, and sightseeing. As a result, more and more people are turning into a dense space. Port space, on the other hand, is also a space vulnerable to disasters which can be attributed to geographical and environmental characteristics. Despite the sensitivity if the issue, in Korea disaster prevention and urban planning have not been clearly established. Therefore, there is a need to provide safety and disaster preventive measures in urban planning considering the characteristics of harbor space.

• Journal of Korean Society for Geospatial Information Science
• /
• v.23 no.2
• /
• pp.3-9
• /
• 2015

Since changes in land use in urban space cause traffic volume and it is closely related to traffic accidents. Therefore, an analysis on the causes of traffic accidents is judged to be an essential factor to establish the measure to reduce traffic accidents. In this regard, the analysis was conducted on the clustering by using the nearest neighbor indexes with regard to the occurrence frequencies of commercial and residential zone based on traffic accident data of the past five years (2009-2013) with the target of local small-medium sized city, Jinju-si. The analysis results, obtained in this study, are as follows: the occurrence frequency of traffic accidents was the highest in spring and the lowest in winter respectively. The clustering of traffic accident occurrence at nighttime was stronger than at daytime. In addition, terms of the analysis on the clustering of traffic accident according to land use, changes according to the seasons was not significant in commercial areas, while clustering density in winter tended to become significantly lower in residential areas. The analysis results of traffic accident types showed that the side-right angle collision of cars was the highest in frequency occurrence, and widespread in both commercial areas and residential areas. These results can provide us with important information to identify the occurrence pattern of traffic accidents in the structure of urban space, and it is expected that they will be appropriately utilized to establish measures to reduce traffic accidents.

• Imaging Science in Dentistry
• /
• v.43 no.1
• /
• pp.55-58
• /
• 2013

A ranula is a bluish, transparent, and thin-walled swelling in the floor of the mouth. They originate from the extravasation and subsequent accumulation of saliva from the sublingual gland. Ranulas are usually limited to the sublingual space but they sometimes extend to the submandibular space and parapharyngeal space, which is defined as a plunging ranula. A 21-year-old woman presented with a complaint of a large swelling in the left submandibular region. On contrast-enhanced CT images, it dissected across the midline, and extended to the parapharyngeal space posteriorly and to the submandibular space inferiorly. Several septa and a fluid-fluid level within the lesion were also demonstrated. We diagnosed this lesion as a ranula rather than cystic hygroma due to the location of its center and its sublingual tail sign. As plunging ranula and cystic hygroma are managed with different surgical approaches, it is important to differentiate them radiologically.

• Imaging Science in Dentistry
• /
• v.33 no.4
• /
• pp.239-244
• /
• 2003

Malignant fibrous histiocytoma (MFH) is a pleomorphic soft tissue sarcoma. Three cases of MFH were reported in our study. The first case involved in the right infratemporal fossa of a 32-year-old female was presented. MR imaging revealed a 5.0 × 3.3 cm soft tissue mass of inhomogeneous high signal intensity. The second case was found in the right hard palate of a 66-year-old male. CT demonstrated bone destruction and MR imaging showed a 4 × 4 cm sized soft tissue mass of heterogeneous high signal intensity. The final case was found in the left masticator space of a 37-year-old male. The CT image showed a large mass with massive bone destruction of the left mandibular ramus, while the MRI displayed a soft tissue mass, 8 cm diameter. Our cases exhibited the general features of MFH. MRI is essential in the imaging of MFH, namely to depict tumor borders and demonstrate relationships with adjacent structures.