• Journal of Advanced Marine Engineering and Technology
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• v.32 no.1
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• pp.27-32
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• 2008

Recently, we have a lot of interest in alternative fuels to provide energy independence from oil producing country and to reduce exhaust emissions for air pollution prevention. Biodiesel, which can be generated from natural renewable sources such as new or used vegetable oils or animal fats, may be used as fuel in diesel engine of compression ignition engine. In this paper, the test results on specific fuel consumption and exhaust emissions of neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were presented using four stroke, direct injection diesel engine, especially this biodisel was produced from soybean oil at our laboratory. This study showed that Soot and CO emission were decreased as the blending ratios of biodiesel to diesel oil increased, on the other hand NOx emission was slightly increased because of the oxygen content in biodiesel. Also, the biodiesel blends yielded slightly higher specific fuel consumption than that of diesel oil because of lower heating value of biodiesel.

• Journal of Korea Foundry Society
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• v.28 no.5
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• pp.231-236
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• 2008

H-NCM(Hong-Nanocast Method)has several benefits such as a lower porosity defect and high quality casting comparing to conventional die casting. Influence of casting parameters of hybrid-lower arm in rheocasting process on the slurry flow and the amount of porosity defect was investigated using experimental and simulation methods. In the present study, the Carreau model was adopted to simulate the pattern of rheological flow. Optimal casting paremeters such as injection speed and stroke variations were established. Sound products with integral microstructure and sound shape of joinning different materials of Al and steel pipe without deforming the steel pipe were obtained by the H-NCM slurry and X-ray analysis also showed integral condition throughout the entire parts.

• Environmental Analysis Health and Toxicology
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• v.19 no.3
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• pp.287-294
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• 2004

Diabetic complication is one of major risk factors leading to vascular disease such as atherosclerosis, stroke, coronary heart disease and etc. Several factors affecting the acceleration of diabetic vascular complication have been known such as hypertension, hyperlipidemia, immune complex and genetic factors. To screen and develop new therapeutics agents for diabetic vascular complication, it is strongly needed to develop animal models for diabetic complications. However in rodents models, diabetic complications is not well developed. Furthermore to assess the possibility of new therapeutics for diabetic vascular complications, diabetic animal models which have the risk factors of diabetic complications is needed. We aim to develop and establish an diabetic animal model which have diabetic complications with hyperlipidemia which is one of risk factors for diabetic complications. We induced insulin -dependent diabetes by intra. venous injection of streptozotocin (35 mg/kg/day) in RICO rats which is a spontaneous animal model for hyperlipidemia. Our models (STZ RICO) showed hyperglycemia, persistent high level of plasma cholesterol and triglyceridemia with severe diabetic renal changes until 28 weeks after induction of diabetes. STZ-RICO rats could be used for the evaluations of newly developed diabetic drugs.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.3
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• pp.741-747
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• 2007

This study evaluated neuroprotective effects of Yanggyuksanhwa-tang (YST), which have been known to be efficacy in the treatment of the stroke and diabetes. on focal cerebral ischemia of diabetic rats. On primary experiment, diabetic condition in rats was induced by streptozotocin injection, then, focal cerebral ischemia was induced by the middle cerebral artery occlusion (MCAO) under the diabetic condition. Then neuroprotective effect of YST was observed with changes of infarct size and volume, expressions of c-Fos, Bax, and hypoxia inducible factor (HIF)-1${\alpha}$ in the brain tissues by using 2% 2,3,5-triphenyltetrazolium chloride (TTC) staining and immunohistochemistry. YST treatment showed a significant decrease of infarct size and volume induced by MCAO in diabetic rats. YST treatment showed a significant decrease of c-Fos and Bax positive neurons in cortex penumbra. YST treatment showed a decrease of HIF-l${\alpha}$ positive neurons in cortex penumbra, but it was not significant statistically. These results suggest that YST has effects on neuroprotection against cerebral infarct under diabetic condition. And it is supposed that neuroprotective effect of YST reveals by anti-apoptosis mechanism.

• International Journal of Automotive Technology
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• v.8 no.4
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• pp.437-444
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• 2007

This paper experimentally investigates the effects of oxygen-enriched air (OEA) on the running behaviors of an LPG SI engine during both start/warm-up (SW) and hot idling (HI) stages. The experiments were performed on an air-cooled, single-cylinder, 4-stroke, LPG SI engine with an electronic fuel injection system and an electrically-heated oxygen sensor. OEA containing 23% and 25% oxygen (by volume) was supplied for the experiments. The throttle position was fixed at that of idle condition. A fueling strategy was used as following: the fuel injection pulse width (FIPW) in the first cycle of injection was set 5.05 ms, and 2.6 ms in the subsequent cycles till the achieving of closed-loop control. In closed-loop mode, the FIPW was adjusted by the ECU in terms of the oxygen sensor feedback. Instantaneous engine speed, cylinder pressure, engine-out time-resolved HC, CO and NOx emissions and excess air coefficient (EAC) were measured and compared to the intake air baseline (ambient air, 21% oxygen). The results show that during SW stage, with the increase in the oxygen concentration in the intake air, the EAC of the mixture is much closer to the stoichiometric one and more oxygen is made available for oxidation, which results in evidently-improved combustion. The ignition in the first firing cycle starts earlier and peak pressure and maximum heat release rate both notably increase. The maximum engine speed is elevated and HC and CO emissions are reduced considerably. The percent reductions in HC emissions are about 48% and 68% in CO emissions about 52% and 78%; with 23% and 25% OEA, respectively, compared to ambient air. During HI stage, with OEA, the fuel amount per cycle increases due to closed-loop control, the engine speed rises, and speed stability is improved. The HC emissions notably decrease: about 60% and 80% with 23% and 25% OEA, respectively, compared to ambient air. The CO emissions remain at the same low level as with ambient air. During both SW and HI stages, intake air oxygen enrichment causes the delay of spark timing and the increased NOx emissions.

• Journal of Korean Neurosurgical Society
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• v.48 no.5
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• pp.391-398
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• 2010

Objective : This study was designed to validate the cell trafficking efficiency of the in vivo bioluminescence image (BLI) study in the setting of transplantation of the luciferase expressing bone marrow-derived mesenchymal stem cells (BMSC), which were delivered at each different time after transient middle cerebral artery occlusion (MCAO) in a mouse model. Methods : Transplanting donor BMSC were prepared by primary cell culture from transgenic mouse expressing luciferase (LUC). Transient focal infarcts were induced in 4-6-week-old male nude mice. The experiment mice were divided into five groups by the time of MSC transplantation : 1) sham-operation group, 2) 2-h group, 3) 1-day group, 4) 3-day group, and 5) 1-week group. BLI for detection of spatial distribution of transplanted MSC was performed by detecting emitted photons. Migration of the transplanted cells to the infarcted area was confirmed by histological examinations. Differences between groups were evaluated by paired t-test. Results : A focal spot of bioluminescence was observed at the injection site on the next day after transplantation by Signal intensity of bioluminescence. After 4 weeks, the mean signal intensities of 2-h, 1-day, 3-day, and 1-week group were $2.6{\times}10^7{\pm}7.4{\times}10^6$. $6.1{\times}10^6{\pm}1.2{\times}10^6$, $1.7{\times}10^6{\pm}4.4{\times}10^5$, and $8.9{\times}10^6{\pm}9.5{\times}10^5$, respectively. The 2-h group showed significantly higher signal intensity (p<0.01). The engrafted BMSC showed around the infarct border zones on immunohistochemical examination. The counts of LUC-positive cells revealed the highest number in the 2-h group, in agreement with the results of BLI experiments (p<0.01). Conclusion : In this study, the results suggested that the transplanted BMSC migrated to the infarct border zone in BLI study and the higher signal intensity of LUC-positive cells seen in 2 hrs after MSC transplantation in MCAO mouse model. In addition, noninvasive imaging in real time is an ideal method for tracking stem cell transplantation. This method can be widely applied to various research fields of cell transplantation therapy.

• Journal of Pharmacopuncture
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• v.2 no.1 s.2
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• pp.73-91
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• 1999

This study was carried out to invastigate the researches of Snake Venom and snakes which used in treatment 1. The fist literature that used the snake for treatment is Shin Nong Ben Cao Jing 2. Composition of Snake Venom is consist of Enzymatic proteins ; Phospholipase A(A1-2), Protease, L-amino acid oxidase etc, and Non-enzymatic proteins ; Crotamine(Cytolysin), Proteolytic factor(Hematoxin), Crotoxin(Neurotoxin) etc. 3. Main toxins in Snake Venom are Hematoxin, Cytolysin, Neurotoxin and Cardiotoxin. Lethal dose 50 value of Agkistrodon brevicaudus is $45.87{\mu}g$/18g, Agkistrodon saxatilis is $10.28{\mu}g$/18g, Agkistrodon ussuriensis is $8.68{\mu}g$/18g, therefore Agkistrodon ussuriensis has strongist Snake Venom of all in Korea. 4. Pharmacological actions of Snake Venom are anticoagulation, thrombolytic function, hypotensor etc. 5. Systemic syndromes and signs after snakebite are Dizziness(25.7%), Vomitting(23.1%), Fever(22%), Visual disturbance(18%), Headache(17.7%) and Dyspnea(17.6%), etc. 6. Local syndrome and sign after snakebite is Discoloration(54.2%), Bleeding(20.2%), Bullae(10.7%), Skinulcer(10.8%), etc. 7. Pathological syndromes after snakebite are WBC increase, Urine protein, Urine sugar, Haematuria and elevation of S-GDT, S-GPT etc. These syndromes are leaded by Hematoxin and Cytolysin. 8. Complication signs after snakebite are Cellulitis, Gastritis, Lympoma, Abscess etc. 9. Common function of Viperidae(Agkistrodon acutus or Zaocys dhumnades etc) is expelling the wind(祛風), removing obstruction in the channels(通絡), antipastic function(止痙). And it is used in order to cure hemiparesis, hemiplegia, facial palsy and CVA disease, etc. 10. Using way of snake for medical treatment is various like Herbal alchol therapy, pill, powder and injection etc. The Study on the Snake Venom should be carried out continuously for using of medical treatment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.1
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• pp.46-58
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• 1997

The energy saving is one of the most important factors for profit in marine transportation. In order to reduce the fuel oil consumtion the ship's propulsion efficiency must be increased as possible. The propulsion efficiency depends upon a combination of an engine and a propeller. The propeller has better efficiency as lower rotational speed. This situation led the engine manufacturers to design the engine that has low speed, long stroke and a small number of cylinders. Consequently, the variation of rotational torque became larger than before because of the longer delay-time in fuel oil injection process and an increased output per cylinder. As this new trends the conventional mechanical-hydrualic governors for engine speed control have been replaced by digital speed controllers which adopted the PID control or the optimal control algorithm. But these control algorithms have not enough robustness to suppress the variation of the delay-time and the parameter perturbation. In this paper we consider the delay-time and the perturbation of engine parameters as the modeling uncetainties. Next we design the robust servo controller which has zero offset in steady state engine speed, based on H sub($\infty$) control theory. The validity of the controller was investigated through the response simulation. We used a personal computer and an analog computer as the digital controller and the engine (plant) part respectively. And, we could certify that the designed controller maintains its robust servo performance even though the engine parameters may vary.

• The Journal of Internal Korean Medicine
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• v.30 no.3
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• pp.612-623
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• 2009

Objectives : The water extract of Sopung-tang (SPT) has been traditionally used in the treatment of acute stroke in Oriental Medicine. Pro-inflammatory cytokines play a critical role in the onset of post-ischemic inflammatory cascades. The present study was designed to investigate the effects of SPT on pro-inflammatory cytokine production in a photothrombotic ischemia mouse model. Methods : After SPT oral administration to the mice for five days, with using Rose Bengal and cold light, photothrombotic ischemia lesion was induced in stereotactically held male BALB/c mice. Also, results including, gross finding lesion size, histopathological finding changes, and inflammatory cytokine expression changes from the photothrombotic ischemia mouse model were observed. Results : The photothrombotic ischemia lesion was decreased by the oral injection of SPT. Also, SPT inhibited the expression of TNF-$\alpha$, IL-$1{\beta}$, IL-6, the active form of caspase-3 protease, and transglutaminase-2 in the photothrombotic ischemia lesion. Conclusions : These results suggest that SPT protects the ischemic death of brain cells through suppression of the production of anti-inflammatory cytokines and catalytic activation of caspase-3 protease in the photothrombotic ischemia mouse model.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.47-52
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• 2013

The higher energy efficiency for ship and the lower pollution for global environment are required strictly. However the performance of marine diesel engine is gradually deteriorated with time. And also the operation condition is varied with sea conditions. Hence the optimization for operating condition of marine engines is needed for energy saving and environment kindly. In this paper, it was attempted to investigate the influence of aging for marine diesel engine. The deterioration of engine performance is assessed by the calculation results of the simulation program for two-stroke marine diesel engine developed by author which was reported before. And three parameters for deterioration of engine performance were considered such as lower efficiency of turbocharger by fouling, increase of blow-by gas due to wear of cylinder liner and getting worse of combustion by poor injection. By the results, it was shown that the influence of engine performance by aging was relatively not so small - 10.4 bar low in Pmax and 3.2% decrease in Pmi.