• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.56-62
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• 2008

A synthetic gas reformed from hydrocarbon-based fuels consists of $H_2$, CO and $N_2$. Hydrogen contained in the synthetic gas is a very useful species in chemical processes, due to its wide flammability range and fast burning speed. The ESGI (Exhaust Synthetic Gas Injection) technology is developed to shorten the light-off time of three way catalysts through combustion of the synthetic gas in the exhaust manifold during the cold start period of SI engines. Before the ESGI technology is applied to the test engine, the authors set a test rig that consists of gas temperature and composition controllers, an exhaust pulse generator and an exhaust manifold with a visualization window, in order to optimize the point and conditions of injection of the synthetic gas. Through measuring burned gas temperatures and taking photographs of synthetic gas combustion at the outlet of the exhaust manifold, the authors tried to find the optimal injection point and conditions. Analysis of burned gas composition has been performed for various $O_2$ concentrations. As a result, when the synthetic gas is injected at the port outlet of the cylinder No. 4 and $O_2$ concentration exceeds 4%, combustion of the synthetic gas is strong and effective in the exhaust manifold.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.248-255
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• 2013

The objective of this study is to optimize the Metal Injection Molding(MIM) process with design of experiments(DOE) and numerical analysis. To derive the optimal process condition, experiment or numerical analysis was performed under various process conditions. To analyze the interaction among influential factors contributing to the temperature at flow front and response surface in MIM, both central point and axial point were added to the full factorial design with 2 levels and 5 factors and then their impacts on response variable in 43 experimental conditions were analyzed and the significance was evaluated. As a result, sprue, runner, and gate were completely filled in about 0.247 seconds after injection, the front part of the green body was filled in about 0.3344 seconds, the green body except gate, etc changed to almost solid state in about 3.29 seconds, the Packinging pressure was completed in about 6.29 seconds, and the green body inside and outside and sprue, etc became solid in 13.2 seconds. The impact of individual or reciprocal action of factors on the temperature at flow front was analyzed through regular probability, test statistics, main effect, and interaction effect. As a result, of a total of 31 combinations of factors, 9 unit factors and reciprocal actions were significant, and the screening was also possible. A proper regression equation was drawn with regression analysis and response surface design on the response variable of temperature at flow front, and the applicability could be verified.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.2
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• pp.153-159
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• 2004

The purpose of this research is to investigate the performance of swirl combustion chamber diesel engine by changing the jet passage area, the depth and shape of the piston top cavity (main chamber). The performance of diesel engine with newly changed swirl combustion chamber was tested through the experimental conditions as engine speed, load and injection timing etc. The test results were compared and analyzed. And another purpose of this research is to make a new diesel engine that is satisfied fuel consumption and regulation value of exhaust gas. 1. The rate of fuel consumption was affected significantly by the jet passage area at the high speed and load than low speed and low load. The influence of jet passage large area was proven to decrease the rate of fuel consumption. 2. Smoke was affected significantly by the depth of the piston top cavity, but exhaust temperature and the rate of fuel consumption wasn't affected. The rate of fuel consumption was affected by changing injection timing. 3. The rate of fuel consumption, exhaust temperature and Smoke were affected significantly by the shape of the piston top cavity from rectangular to trapezoid. That is we have all high value. The exhaust smoke density and exhaust gas temperature depended sensitively on variation of the injection timing rather than the shape of the combustion chamber within the experimental conditions. 4. We made a new diesel engine that is satisfied design target values(sfc=190 g/hr, NOx + THC=6.0 g/KWh, PM=0.3 KWh), the rate of fuel consumption and emission standard etc., through changing injection timing at the maximum torque point and rated power point. Although we have a little high NOx value.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.4
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• pp.691-696
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• 2011

In order to the neuroprotective effect of electroacupuncture (EA), the present study examined the effects of electroacupuncture inacupoint ST36 (Stomach 36) on trimethyltin chloride (TMT)-induced cognitive impairments rat using the Morris water maze (MWM) task and immunohistochemistry staining. The rats were randomly divided into the following groups: naive rat (Normal), TMT injection rat (Control), TMT injection + EA treated rat inacupoint ST36 (ST36) and TMT injection + EA treated rat in non-acupoint, base of tail (Non-AC). Electroacupuncture (2Hz, 2mA, and 10 minutes)was applied either to the acupuncture point ST36 or the nonacupuncture point in the tail for the last 14 days. In the water maze test, the animals were trained to find a platform in a fixed position during 4d and then received 60s probe trial on the $5^{th}$ day following removal of platform from the pool. Rats with TMT injection showed impaired learning and memory of the tasks and treatment with EA in acupoint ST36 (P<0.05) produced a significant improvement in escape latency to find the platform after $2^{nd}$ day and retention trial in the Morris water maze. Consistent with behavioral data, treatment with EA in acupoint ST36 also significantly increased expression of Choline acetyltransferase (ChAT) and Acetylcholinesterase (AChE) immunoreactive neurons in the hippocampus compared to the Control group. These results demonstrated that EA in acupoint ST36 has a protective effect against TMT-induced neuronal and cognitive impairments. The present study suggests that EA in acupoint ST36 might be useful in the treatment of TMT-induced learning and memory deficit.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.3 s.234
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• pp.356-367
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• 2005

The spray characteristics of DISI injector have a great role in gasoline engine efficiency and emission. Thus, many researchers have studied to investigate the spray characteristics of swirl and slit injectors that are used in a DISI engine. In this study, we tried to provide spray parameters, which affect on the spray characteristics such as injection pressure, ambient pressure and ambient temperature. In addition, we calculated $t_{b}\;and\;t_{c}$ to investigate the break up mechanism of test injectors and obtained $C_{v}$ to evaluate the spray characteristics. As the ambient pressure increases in case of slit injector, $C_{v}$ decreases. The laser-induced exciplex fluorescence (LIEF) technique, which is based on spectrally resolved two-color fluorescent emissions, has applied to measure the liquid and vapor phases for on evaporating spray simultaneously. The TMPD/naphthalene proposed by Melton is used as a dophant to detect exciplex signal. The temporal and spatial distribution of liquid and vapor phases during the mixture formation process was measured by this technique. In the LIEF technique, the vapor phase is detected by the monomer fluorescence while the liquid phase is tracked by the exciplex fluorescence. From this experiment, we found that the spray area of the vapor phase is increased with elapsed time after injection and the area of liquid is decreased when the ambient pressure is 0.1MPa. However, the area tends to increase until the end of injection when the ambient pressure is 1.0MPa.

• Journal of Digital Convergence
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• v.18 no.4
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• pp.341-346
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• 2020

Polymethyl methacrylate (PMMA), a self-curing resin mainly used in removable orthodontic appliances, is an acrylic resin mainly used in the field of modern dentistry. As an advantage, it has been used for a long time as a material for orthodontic devices in dentistry due to its color and volume, tissue affinity, and stability. The production of PMMA can be divided into self-polymerization method and thermal polymerization method according to activation method. Self-curing resins have long been used as orthodontic devices. The resin injection method is largely divided into a sprinkle-on method and a mixing method. In this study, we intend to test the mechanical properties according to the resin injection method of the orthodontic device, such as strength, modulus of elasticity, and surface roughness. There was no significant difference in strength as a result of three-point bending strength test on rectangular specimens (1.4 × 3.0 × 19.0 mm) of orthodontic PMMA. There was also no significant difference in hardness. There was no significant difference in surface roughness. It was confirmed that the orthodontic PMMA had no significant difference in mechanical properties according to the resin injection method of the orthodontic device.

• Clinical Pain
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• v.18 no.2
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• pp.59-64
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• 2019

Objective: This study evaluated the feasibility of ultrasound-guided lumbar nerve root block (LNRB) and S1 nerve root block by identifying spread patterns via fluoroscopy in cadavers. Method: A total of 48 ultrasound-guided injections were performed in 4 fresh cadavers from L1 to S1 roots. The target point of LNRB was the midpoint between the lower border of the transverse process and the facet joint at each level. The target point of S1 nerve root block was the S1 foramen, which can be visualized between the median sacral crest and the posterior superior iliac spine, below the L5-S1 facet joint. The injection was performed via an in-plane approach under real-time axial view ultrasound guidance. Fluoroscopic validation was performed after the injection of 2 cc of contrast agent. Results: The needle placements were correct in all injections. Fluoroscopy confirmed an intra-foraminal contrast spreading pattern following 41 of the 48 injections (85.4%). The other 7 injections (14.6%) yielded typical neurograms, but also resulted in extra-foraminal patterns that occurred evenly in each nerve root, including S1. Conclusion: Ultrasound-guided injection may be an option for the delivery of injectate into the S1 nerve root, as well as lumbar nerve root area.

• International Journal of Automotive Technology
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• v.8 no.1
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• pp.27-31
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• 2007

The number of vehicles employing diesel engines is rapidly rising. Accompanying this trend, application of an after-treatment system is strictly required as a result of reinforced exhaust regulations. The Diesel Particulate Filter (DPF) system is considered as the most efficient method to reduce particulate matter (PM), but the improvement of a regeneration performance at any engine operation point presents a considerable challenge by itself. Therefore, the present study evaluates the effect of fuel injection characteristics on regeneration performance in a DOC and a catalyzed CR-DPF system. The temperature distribution on the rear surface of the DOC and the exhaust gas emission were analyzed in accordance with fuel injection strategies and engine operating conditions. A temperature increase more than BPT of DPF system was obtained with a small amount fuel injection although the exhaust gas temperature was low and flow rate was high. This increase of temperature at the DPF inlet cause PM to oxidize completely by oxygen. In the case of multi-step injection, the abrupt temperature changes of DOC inlet didn't occur and THC slip also could not be observed. However, in the case of pulse type injection, the abrupt injection of much fuel results in the decrease of DOC inlet temperatures and the instantaneous slip of THC was observed.

• The Korean Journal of Pain
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• v.10 no.2
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• pp.220-224
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• 1997

Background: The incidence of pain on injection of propofol varies between 30 and 100%. A variety of pretreatments have been tried to alleviate this problem such as a local anesthetics, cooling and opioids. However, none of these pharmacological maneuvers were satisfactory yet. In a recent study, subhypnotic doses of both thiopental sodium and propofol decrease the acute pain. We report a comparison of thiopental sodium, lidocaine and placebo on the incidence and severity of pain on injection of propofol. Method: A controlled, double-blind study was performed to compare the prior administration of intravenous saline 2 ml(n=30, group S), lidocaine 20 mg(n=30, group L) and thiopental sodium 50 mg(n=30, group T) in alleviating the pain by propofol. Injection pain was assessed with the four-point verbal categorical scoring system. Result: The incidence of injection pain during induction was lower in group L(30%) and T(17%) than group S(77%). The incidence of injection pain was lower in group T(17%) than group L(30%), but not significant statistically. The pain scores for recall of pain in the recovery room was simlar to those pain during propofol induction. Conclusion: The pretreatment of thiopental sodium can be effective in reducing both incidence and severity of propofol injection pain and has similar effect to lidocaine to prevent propofol injection pain.

• Journal of the Korea Convergence Society
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• v.12 no.1
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• pp.127-132
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• 2021

The intravenous injection monitoring system used by medical institutions was developed to remotely provide patients with the amount of intravenous injected and the termination point of the injection. In order to measure the amount of intravenous injection input, the weight or flow rate of the level going out from the inside to outside of the intravenous injection can be observed with a measuring sensor. The criteria for devices that apply herein are accuracy and vigilance. In addition, it is compact and should be easy to use when installing intravenous injection on patients. In medical institutions, the accuracy of the measured values must be high, and economically inexpensive devices are required. In this study, low-cost small-weight-centered load cell sensors were applied, and algorithms were applied to reduce the artefact by external movement by converging with gyro sensors for accuracy of measurements. As a result, it was possible to reduce the error of measurement, thereby improving the accuracy of the intravenous injection monitoring measurement value.