• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.33-35
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• 2013

The present work is an experimental investigation on potential operating range using directly injected gasoline fuel in a single-cylinder compression ignition (CI) engine. The objectives of present study were to apply auto-ignited combustion to gasoline fuel and to evaluate potential operating range. In order to auto-ignite gasoline fuel in CI engine, the fuel direct-injection system and the intake air system were modified that a flow rate and temperature of intake air were regulated. The heat-release rate (HRR), net indicated mean effective pressure (IMEP), start of combustion (SOC), and combustion duration were derived from in-cylinder pressure data in a test engine, which has 373.33cc displacement volume and 17.8 compression ratio. The exhaust emission characteristics were obtained emission gas analyzer and smoke meter on the exhaust line system.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.31 no.2
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• pp.56-60
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• 2020

Vocal fold injections are usually performed with a patient wake in an office under local anesthesia. For comfortable and safe office-based procedures, thorough anesthesia and premedication should be provided to the following three regions; nasal cavity, oropharynx, and larynx. Topical lidocaine is most widely used anesthetics on office based procedure. Lidocaine has a low to intermediate potency, 45 minutes to 60 minutes' duration of action, and onset of sufficient anesthesia within 90 seconds of topical administration. Tetracaine, prilocaine, ropivacaine, and bupivacaine also have been used in the office-based procedures. Nasal decongestant, oxymetazoline, is also used for widening nasal cavity by constriction of nasal mucosa. The amount of topical and local anesthetics used in vocal fold injection rarely exceeds toxic doses. The physician should know proper anesthesia techniques and must be familiar with the safe dose and complication of all anesthetics used.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.147-156
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• 2008

As the management of fuel efficiency becomes globally reinforced in attempts to find an environment-friendly vehicle that will operate against global warming, the interest in and the demand for the type of vehicle with a high-efficiency diesel engine using light oil. However, it also emits a greater amount of PM (particulate matter) and NOx than emissions from vehicles using other types of fuels. Therefore, the DME (Dimethyl Ether), an oxygen containing fuel draws attention as an alternative fuel for light oil that can be used for diesel engines since it generates very little smoke. But to develop and compare performance of an electric controlled common-rail DME engine, engine tests requires optimized injection conditions at required engine RPM and engine torque. These injection conditions cannot be set freely and the data configuration through the experimentally repeated application requires much time as well as a significant amount of errors and effort. The object of this study is to configure the basic injection map using the results of the DME engine experiments performed so far. For this, in this study, the functionalization of the required equations were performed along with the basic review of the factors that had influence on the data map. Through this, the information on the injection pressure, injection amount, injection duration, injection timing, etc. under certain operation condition could be obtained.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.60-65
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• 2004

Numerical simulations and experiments have been carried out to investigate the effect of fuel injection nozzles on the combustion and NOx formation processes in a medium-speed marine diesel engine. Spray visualization experiment was performed in the constant-volume high-pressure chamber to verify the numerical results on the spray characteristics such as spray angle and spray tip penetration. Time-resolved spray behaviors were captured by high-speed digital camera and analyzed to extract the information on the spray parameters. Spray and combustion phenomena were examined numerically using FIRE code. Wave breakup and Zeldovich models were adopted to describe the atomization characteristics and NOx formation processes. Numerical results were verified with experimental data such as cylinder pressure, heat release rate and NOx emission. Finally, the effects of fuel injection nozzles on the engine performance were investigated numerically to find the optimum nozzle parameters such as fuel injection angle, nozzle hole diameter and number of nozzle holes. From this study, the optimum fuel injection nozzle (nozzle hole diameter, 0.32 mm, number of nozzle holes, 8 and fuel injection angle, $148^{\circ}$) was selected to reduce both the fuel consumption and NOx emission. The reason for this selection could be explained from the highest fuel-air mixing in the early phase of injection due to the longest spray tip penetration and the highest heat release rate after $19^{\circ}$ ATDC due to the increased injection duration.

• Journal of the Korean institute of surface engineering
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• v.41 no.5
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• pp.245-253
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• 2008

The porous metal material is used for injection metal mold with a great deal of gas production because it makes plenty of gas exhausted through pores formed in the metal mold. A canning HIP method was conventionally used for manufacturing of porous metals, but because of difficulty of process control and high cost of production its application was limited. In this experiment, porous metal mold material was produced by an enhanced vacuum sintering method with simply controlled and economical process and porosities/mechanical properties with variation of sintering temperature and duration time during vacuum sintering were studied. As a result, quality goods were obtained at optimized conditions as follows: sintering temperature of $1230^{\circ}C$, duration time of 2 hr and showed superior properties in wear loss and thermal conductivity and the same properties in hardness, TRS (Transverse Rupture Strength), and thermal expansion coefficient in comparison with those under canning HIP.

• Journal of the Korean Society of Combustion
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• v.20 no.3
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• pp.13-20
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• 2015

The performance of a direct-injection diesel engine often depends on the strength of swirl or squish, the shape of combustion chamber, the number of nozzle holes, etc. This is natural because the combustion in the cylinder was affected by the mixture formation process. Since the available duration to make the mixture formation of air-fuel is very short, it is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this paper, the combustion process of a common-rail diesel engine was studied by employing two kinds of pistons. One has several cavities on the piston crown to intensify the squish during the compression stroke in order to improve the atomization of fuel, we call this multi cavity piston in this paper. The other is a toroidal single cavity piston, generally used in high speed diesel engines. To take photographs of flame and flaming duration, a four-stroke diesel engine was remodeled into a two-stroke visible single cylinder engine and a high speed video camera was used.

• The Korean Journal of Nuclear Medicine
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• v.3 no.2
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• pp.49-54
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• 1969

The present study has been undertaken to analyze scan manifestations in obstructive jaundice. Scan changes were cprrelated with the duration of jaundice. In addition, clearance rates of trace dose of colloidal radiogold were assessed in each case. The materials were consisted of 19 cases with surgically and/or histopathlogically verified obstructive jaundice from various causes including common duct stone, empyema of the gall bladder and carcinoma of the pancreas head etc. Blood clearance rates of colloidal $^{198}Au$ were determined after the injection of 8 uCi by simple geometrical drawing of recorded strip charts. Scan was performed following additional injection of the same radiogold. In 16 out of 19 cases, the scan revealed rather typical "arborifrom" mottlings around the porta hepatis. The intensity and appearance of such mottlings on the scan was related with the duration of jaundice and level of serum bilirubin and alkaline phosphatase. The blood clearance rates remained to be within normal range in 74 percent of the patients. In the remaining 26 percent, clearance rates ranged between 4.1 and 6 minutes. It is concluded that the association of "arboriform" mottlings and normal or mildly delayed clearance rates in the patients with jaundice is characteristic of obstructive changes in the biliary system.

• Archives of Plastic Surgery
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• v.36 no.6
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• pp.685-690
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• 2009

Purpose: Autologous fat graft is a widely accepted technique used for soft tissue augmentation. Nonetheless, the use of fat graft is limited by unpredictable survival rates and repeated grafting. To avoid repeated grafting, cryopreserved fat graft technique has recently been widely used. On the other hand, the number of patients with chronic infection(who received cryopreserved fat injection) has currently been increasing. Therefore, this study was focused on the safety of cryopreserved fat injection from the infection. Methods: We collected 150 samples from local aesthetic clinics to examine the safety of cryopreserved autologous fat. To test for microbacterial contaminations of the cryopreserved fat specimens, microbacterial cultures & antibiotics sensitivity tests were performed. Then, we examined possible correlation between the preservation period and donor sites, focused on the results of microbacterial culture. Results: Cultures were positive for Staphylococcus epidermidis in 5 samples(methicillin - resistant Staphylococcus epidermidis in 4 samples), Micrococcus species in 3 samples. An average duration of preservation was 191 days and there was no significant correlation between the duration of preservation and microbacterial growth. Conclusion: Staphylococcus epidermidis was the leading cause of cryopreserved fat contamination, and the resistance to methicillin is common. Based on the above results, aseptic handling of fat during harvesting and preservation appeared to be most important.

• Journal of Embryo Transfer
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• v.29 no.2
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• pp.149-155
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• 2014

The present study was designed to observe the oestrus responses in the indigenous ewe induced by cloprostenol sodium manufactured by two different companies ($Ovuprost^{(R)}$, BOMAC, Newzealandand $Prostenol^{(R)}$, Techno, Bangladesh). Twelve local ewes were divided into 3 groups (n= 8). The ewes in Group I and II were induced by intramuscular injection of $100{\mu}g$ (0.4 ml) of cloprostenol sodium ($Ovuprost^{(R)}$ and $Prostenol^{(R)}$), respectively. The $2^{nd}$ injection in each group was given at 9 days apart. The ewes in Group III were kept as control for observing natural oestrus characteristics and comparing the responses with induced oestrus. Hundred and 75% ewes showed oestrus following $2^{nd}$ injection of $Ovuprost^{(R)}$ and $Prostenol^{(R)}$, respectively. The average time of onset of oestrus following $1^{st}$ and $2^{nd}$ injection of $Ovuprost^{(R)}$ and $Prostenol^{(R)}$ were $50.5{\pm}3.5$ vs $48.0{\pm}0.0h$ and $49.9{\pm}1.9$ vs $49.5{\pm}1.7h$, respectively. There was no significant difference between the two types of cloprostenol sodium group on the onset of oestrus. The average duration of oestrus was $27.5{\pm}0.7$ vs $27.5{\pm}0.0h$ and $25.9{\pm}3.3$ vs $24.2{\pm}0.3h$ in $Ovuprost^{(R)}$ and $Prostenol^{(R)}$ treated ewes, respectively. For natural oestrus, the duration of oestrus was $25.2{\pm}3.3h$. There was no significant difference among the cloprostenol sodium produced by two different companies and natural oestrous ewes on the duration of oestrus. The higher percentages of cornified cells were present in induced oestrus (90 and 85%) compared with natural oestrus (80%), although there was no significant difference among them. The pregnancy rates were 75, 66.7 and 100% in $Ovuprost^{(R)}$, $Prostenol^{(R)}$ and natural oestrous ewes, respectively. The above results indicate the suitability of using cloprostenol sodium for synchronization of oestrus in indigenous ewes in Bangladesh.

• Journal of Korean Foot and Ankle Society
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• v.15 no.1
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• pp.27-31
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• 2011

Purpose: This study evaluated the efficacy of an intra-articular injection of sodium hyaluronate in the treatment of early stage osteoarthritis of the ankle. Materials and Methods: Early stage ankle osteoarthritis (Takakura stage I and II) patients who received hyaluronic acid injection therapy were retrospectively reviewed. Patients underwent intra-articular injections of 2 mL of sodium hyaluronate for 3 consecutive weeks. Clinical evaluation and Visual Analogue Scale (VAS) scoring were performed at every three months after treatment. Results: Total 27 patients were involved and mean age was 55 year old (range 33 to 77 years). There were 13 male and 14 female patients. Mean follow up duration was 13 month and. Pre-intra-articular VAS score was $8.9{\pm}0.7$ and three month follow up score was $3.8{\pm}2.8$. VAS score of last follow up was $3.2{\pm}3.4$. The effect of hyaluronic acid continued about one year when analyzed the VAS score change of the patients followed for more than one year. Patients' satisfaction was "very satisfied" in nine, "satisfied" in 12, "fair" in one, and "not satisfied" in five patients. Overall satisfaction rate was 82%. There were no ankle osteoarthritis stage changes in serial follow up radiograph. Conclusion: Symptomatic relief of signs and symptoms of osteoarthritis of the ankle was achieved by injection of an intra-articular hyaluronate injection. Efficacy of Hyaluronate acid injection persisted more than 1 year in our study. Intra-articular hyaluronate injection to ankle osteoarthritis is safe and effective as knee joint and should be considered as a valid conservative treatment for ankle osteoarthritis.