• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.43 no.5
• /
• pp.343-350
• /
• 2017

The aim of this study is to introduce a surgical technique that can maintain blood supply to prevent condylar resorption in the extracorporeal reduction of condylar fracture. Neither the medial pterygoid muscle on the ramal bone nor the lateral pterygoid muscle on the condylar fragment was detached after vertical ramal osteotomy. Thus, reduction was performed in the intracorporeal state. Therefore, blood supply was expected to be maintained to the fragments of both the condylar and ramal bones. On postoperative radiographs, the anatomical outline of the fractured condyle was well restored, and the occlusion was stable. In the unilateral case, there were no signs of mandibular condylar resorption until postoperative 3 weeks. In the 2 bilateral cases, condylar displacements with plate fractures and screw loosening were observed at postoperative 1 month or 5 months, but radiodensity at the displaced fracture site increased during the follow-up period. Finally, complete remodeling of the condylar fragments with restored anatomic appearance was observed on 8-month or 2-year follow-up radiographs. All cases exhibited good healing aspects with no signs or symptoms of mandibular condylar dysfunction during the postoperative remodeling period after intracorporeal reduction of condylar fracture.

• Journal of Korean Foot and Ankle Society
• /
• v.1 no.2
• /
• pp.112-118
• /
• 1997

Tarsometatarsal fracture-dislocation is uncommon but severe lesion. Since this lesion is sometimes difficult to recognize by roentgenography, it is easily overlooked. Three patients were treated with open reduction and internal fixation with 3.5 mm cannulated screw and K-wire, two had treatment with open reduction and internal fixation with 3.5 mm cannulated screw only and two had treatment with dosed reduction and short leg cast only between January 1994 and May 1996. The duration of follow-up ranged from twelve to twenty-nine months after the diagnosis. Results were assessed by a subjective questiormaire, physical examination, and radiographic analysis. Multiple fixation techniques for maintaining the reduction of tarsometatarsl joint have been introduced. We recent]y used the 3.5 mm cannulated screw for internal fixation of the tarso-first and second metatarsal fracture-dislocation. We think cannulated screw fixation has several advantages; 1. The cannulated screw fixation is more rigid than the K-wire fixation. 2. There is an decreased risk of screw breakage with early weight bearing. 3. It is possible to compress the involved joints, if necessary. There were no disability in all patients. One patient who was treated with delayed open reduction and internal fixation with 3.5 mm cannulated screw and K-wire had a radiographic mild degenerative arthritis. And one patient who was treated with dosed reduction and short leg cast had a mild metatarsus adductus. But. these two patients were symptom free. There was no correlation between the severity of the diastasis and the patient s functional result.

• Journal of ILASS-Korea
• /
• v.29 no.2
• /
• pp.53-59
• /
• 2024

Cars are one of the main causes of air pollution in large cities, and 34.6% of domestic air pollution emissions come from mobile sources, of which cars account for 69.6%. In particular, the importance of nitrogen oxides (NOx) and particulate matter (PM), which are major pollutants in diesel vehicles, is increasing due to their high contribution to emissions. Therefore, in this study, the problem of natural regeneration caused by low exhaust gas temperature during low speed and low load operation was solved by applying a complex regeneration DPF that is not affected by temperature conditions to large diesel vehicles with higher driving time and engine displacement than small and medium-sized vehicles. And the feasibility of application to large diesel vehicles was reviewed by measuring the emission reduction efficiency. As a result of the reduction efficiency test on the actual vehicle durability product, PM showed a reduction efficiency of 84% to 86%, and the reduction efficiency of gaseous substances showed a high reduction efficiency of over 90%. The actual vehicle applicability test was completed with three driving patterns: village bus vehicle, police car, and road-going construction equipment vehicle, and no device problems occurred until the end of the test. Both load and no-load smoke measurement results showed a smoke reduction efficiency of over 96%.

• Journal of the korean Society of Automotive Engineers
• /
• v.11 no.2
• /
• pp.8-12
• /
• 1989

본 강좌에서는 연소과정중에서의 NOx 생성기구 및 기존의 NOx 저감방법과 최근에 발표된 바 있는 연소방법의 변화에 의한 NOx의 생성억제 가능성에 대한 결과를 소개한다.

• Journal of Environmental Impact Assessment
• /
• v.16 no.1
• /
• pp.1-13
• /
• 2007

This study was carried out to estimate the emission reduction rates for the regional allowable emissions by special measures to achieve the target air quality in Seoul Metropolitan Area (SMA). A modeling system was designed to validate the details in enforcement regulations set up by local governments based on the current status and plans for air quality improvement. Modeling system was composed of meteorological model (MM5), emission model (SMOKE), and air quality model (CMAQ). Predicted results by this system show quiet well not only daily air pollutants concentration but also the tendencies of wind direction, wind speed and temperature. To achieve the target air quality in Seoul Metropolitan Area (SMA), emission allowances are estimated by seasons and regions. Referring to the base year 2002, it was estimated that emission reduction rates to achieve the intermediate goal in 2007 were 14.2% and 16.6% for NOx and $PM_{10}$, respectively. It was also estimated that 52% of NOx and 48% of $PM_{10}$ reductions from the base year 2002 would be required to accomplish the air quality improvement goal of 22 ppb for $NO_2$, and $40mg/m^3$ for $PM_{10}$ in year 2014. To improve $NO_2$ and $PM_{10}$ concentration through emissions reduction policies, it was found that emissions reduction for the on-road mobile sources would be the most effective in SMA.

• Journal of Microbiology
• /
• v.38 no.3
• /
• pp.180-182
• /
• 2000

The inhibitory effects of nitrate on Fe(III) and humic acid reduction were examined in Shewanella putrefaciens DK-1. Therer is no difference in Fe(III) reduction until 25 hours between cultures using Fe(III) production was decreased drastically when Fe(III) and nitrate were used as electron acceptors. The production of AHQDS(2,6-anthrahydroquinon disulfonate) showed similar patterns when AQDS alone and both AQDS and Fe(III) were used as electron acceptors. When AQDS(2,6-anthraquinon disulfonate) and nitrate were used as electron acceptors, the production of AHQDS was completely inhibited.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.34 no.2
• /
• pp.157-165
• /
• 2008

The aim of this study was to evaluate the efficacy of a topical 0.2% hyaluronic acid (HA) preparation in the management of wound after removal of arch bar for facial bone fracture and a suture site after orthognatic, oral cancer or oral surgery. Forty patients participated in a randomized, placebo controlled, double-blind trial to evaluate the efficacy of the topical HA and preparation. HA topically applied to the wound after removal of arch bar or stitch out, 3 times a day for 4 weeks. Evaluation is performed once a week for 4 weeks. For subjective evaluation, relative pain reduction in visual analog scale (VAS) and existence of heat sensation was accessed. For objective evaluation, gross evaluation, papilla index, existence of wound dehiscence, redness and swelling was checked. The same evaluation was performed in each arch bar group and suture group. For whole subject, 0.2% HA group resulted higher reduction than placebo group in pain of site in first week with significancy. Same findings were seen other weeks but there was no significancy. 0.2% HA group had better result than placebo in objective evaluation (papilla index, wound dehiscence, redness and swelling), but in gross evaluation placebo had better result than 0.2% HA group with no significancy. Subject was divided into suture group and arch bar group. Same aspect was seen, but only suture group had significancy not arch bar group in pain reduction score. 0.2% HA group resulted higher reduction than placebo group in pain of site in first week with significancy, especially in suture group. It reveals topical application of HA in wound especially suture site reduced pain in early stage. And 0.2% HA group had better result than placebo in papilla index, redness and swelling with no statistical significancy. In conclusion, HA has effect of pain reduction and healing promotion in the mucosal wound after oral surgery.

• Proceedings of the KSR Conference
• /
• 1998.05a
• /
• pp.172-183
• /
• 1998

The purpose of this study is to reduce the number of employees hired by Seoul Metropolitan Subway Corporation(SMSC) as a way of responding to deteriorating financial deficit problem. For the reduction, the personnel structure of Seoul Metro Rapid Transit Subway(SMRTS) newly founded in 1995 is benchmarked. Several assumptions are set for seeking the persuasive alternative; 1) no compulsory reduction of existing personnel, 2) raising the salary of SMSC to the same level of SMRTS for compensating intensified work burden, 3) hiring new employees to the amount of one-third of the reduced workforce for minimizing the problems associated with the reduction. The study suggests that the personnel reduction in relevant parts be planned in the following ways; 1) passenger transport part: from daily 3 shifts of 4 group to 2 shifts of 3 group, 2) fleet inspection, civil d: electric engineering, railtrack maintenance, signal parts: from 12 day-off to 10day-off, 3) architecture, AFC parts: from 2 shifts of 3 group to daily work, 4) fleet maintenance, architecture parts: expanding out-sourcing ＆ automation, and 5) headquarter part: 10% reduction of the total of office workers. The study finds, by implementing the plan, that 1,270 employee can be reduced, and that aggregate 106.8 billion won will be saved for the next 10 years.

• Journal of the Korean Arthroscopy Society
• /
• v.2 no.1
• /
• pp.45-50
• /
• 1998

Recently, a variety of arthroscopic techniques have been reported for the treatment of the displaced tibial eminence fracture. The purpose of this study was to describe details of arthroscopic technique using pull-out wire and to evaluate the results. Eleven patients with irreducible type II and type III tibial eminence fractures underwent the arthroscopic reduction and internal fixation using double strand pull-out wiring. The anterior cruciate ligament tibial drill guide was utilized for the reduction of fracture and passage of the guide pins. The tibial eminence fracture was firmly fixed with double strand 26-gauge pull-out wire(0.45mm diameter). Fracture union was achieved at 7.2 weeks (range, six to eight weeks) after operation. All cases were united at the last follow-up. Subjectively, nine patients had no pain and no restriction of daily activities. Two patients with combined injuries had limitation of knee motion(10 to 130 degrees, respectively) and one patient showed mild anterior laxity. Early rehabilitation was enabled without loss of reduction and breakage of pull-out wire. The arthroscopic reduction and internal fixation using pull-out wire showed good results including early rehabilitation, early fracture union, minimal morbidity, and no requirement of the second operation for hard ware removal.

• Applied Chemistry for Engineering
• /
• v.27 no.1
• /
• pp.92-100
• /
• 2016

Low-temperature conversion of nitrogen oxides using plasma-assisted hydrocarbon selective catalytic reduction of (HC-SCR) was investigated. Plasma was created in the catalyst-packed bed so that it could directly interact with the catalyst. The effect of the reaction temperature, the shape of catalyst, the concentration of n-heptane as a reducing agent, the oxygen content, the water vapor content and the energy density on $NO_x$ removal was examined. $NO_x$ conversion efficiencies achieved with the plasma-catalytic hybrid process at a temperature of $250^{\circ}C$ and an specific energy input (SIE) of $42J\;L^{-1}$ were 83% and 69% for one-dimensional Ag catalyst ($Ag\;(nanowire)/{\gamma}-Al_2O_3$) and spherical Ag catalyst ($Ag\;(sphere)/{\gamma}-Al_2O_3$), respectively, whereas that obtained with the catalyst-alone was considerably lower (about 30%) even with $Ag\;(nanowire)/{\gamma}-Al_2O_3$ under the same condition. The enhanced catalytic activity towards $NO_x$ conversion in the presence of plasma can be explained by the formation of more reactive $NO_2$ species and partially oxidized hydrocarbon intermediates from the oxidation of NO and n-heptane under plasma discharge. Increasing the SIE tended to improve $NO_x$ conversion efficiency, and so did the increase in the n-heptane concentration; however, a further increase in the n-heptane concentration beyond $C_1/NO_x$ ratio of 5 did not improve the $NO_x$ conversion efficiency any more. The increase in the humidity affected negatively the $NO_x$ conversion efficiency, resulting in lowering the $NO_x$ conversion efficiency at the higher water vapor content, because water molecules competed with $NO_x$ species for the same active site. The $NO_x$ conversion efficiency increased with increasing the oxygen content from 3 to 15%, in particular at low SIE values, because the formation of $NO_2$ and partially oxidized hydrocarbon intermediates was facilitated.