• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.827-835
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• 2009

Insulin has crucial roles in energy metabolism in all mammals but has been less studied in ruminants. An experiment was conducted to investigate the effects of hypoinsulinemia induction on appetite, performance, carcass composition and blood metabolite levels in sheep. Treatments were intravenous injection of four doses of streptozotocin; 0, 25, 50 and 75 mg/kg BW named C, L, M and H, respectively. Twenty male lambs were divided into four treatment groups. Animals in group H could not continue the experiment because of abnormalities. The duration of the experiment was eight consecutive weeks, and injection was performed at the end of week 3. Feed and water intakes were measured weekly and weight changes of animals were recorded and used for calculation of other growth parameters. Blood samples were collected weekly via venipuncture at fasting and 2.5 h post-prandial and analyzed for hormones and blood metabolites. Results showed a marked hypoinsulinemia in group M with significant decrease in fasted and postprandial insulin concentrations and also fasted leptin concentrations vs. the control group C (p<0.05). Group M showed significant increases in blood glucose, triglycerides, cholesterol, total protein, blood urea nitrogen and ketone body levels vs. group C (p<0.05). After injection, animals in group M showed diabetic hyperphagia and enhanced water intake as compared to group C (p<0.05) but, despite increased feed intake, they did not gain more weight than controls (p<0.05), and consequently, their feed conversion ratio was greater. Protein and fat contents of meat and liver were not significantly different among groups (p>0.05). In conclusion, the results suggested a regulatory role of insulin in energy metabolism of ruminants by exerting two opposing effects; central catabolic and peripheral anabolic.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.2
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• pp.189-195
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• 2005

This paper presents a new velocity estimation strategy for a non-salient permanent magnet synchronous motor drive without high frequency signal injection or special PWM pattern. This approach is based on the d-axis current regulator output voltage of the drive system, which contains the rotor position error information. The rotor velocity can be estimated through a rotor position tracking PI controller that controls the position error at zero. For zero and low speed operation, the PI gain of the rotor position tracking controller has a variable structure according to the estimated rotor velocity. Then, at zero speed, the rotor position and velocity have sluggish dynamics because the varying gains are very low in this region. In order to boost the bandwidth of the PI controller during zero speed, the loop recovery technique is applied to the control system. The PI tuning formulas are also derived by analyzing this control system by frequency domain specifications such as phase margin and bandwidth assignment.

• Journal of the Korean Ceramic Society
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• v.43 no.4 s.287
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• pp.259-263
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• 2006

The applicability of UPT (Ultrasound Pulse Thermography) for real-time defect detection of the ceramic heating plate is described. The ceramic heating plate with superior insulation and high radiation is used to control the water temperature in underwater environment. The underwater temperature control system can be damaged owing to the short circuit, which resulted from the defect of the ceramic heating plate. A high power ultrasonic energy with pulse duration of 280 ms was injected into the ceramic heating plate in the vertical direction. The ultrasound excited vibration energy sent into the component propagate inside the sample until they were converted to the heat in the vicinity of the defect. Therefore, an injection of the ultrasound pulse wave which results in heat generation, turns the defect into a local thermal wave transmitter. Its local emission is monitored and recorded via the thermal infrared camera at the surface which is processed by image recording system. Measurements were Performed on 4 kinds of samples, composed of 3 intact plates and the defect plate. The observed thermal image revealed two area of crack in the defective ceramic heating plate.

• Journal of Nutrition and Health
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• v.31 no.7
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• pp.1093-1099
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• 1998

Dioscorea japonica Thunb its effects has been used in f31k remedies f9r various purposes including treatment of diabetes, on hypoglycemic actiity and energy metabolism were investigated. The plant was extracted with methanol(MeOH) and fractionated into four layers hexane, chloroform(CHCI$_3$), butanol(BuOH), and $H_2O$. Diabetes mellitus was induced in male Sprague-Dawley rats by the injection of streptozotocin(STZ) into tail vein at a dose of 45mg/kg body weight(BW). Sprague-Dawley male rats weighing 160-200g were divided into five groups a diabetic control and four experimental groups such as hexane group, CHCl$_3$ group, BuOH group, and $H_2O$ group. The rats of all groups were fed on a AIN-76 diet and the four experimental groups were orally administered each fraction(500mg/kg BW) for 12 days. The diabetic control group was orally administered 5% carboxymethyl cellulose. The body weights were monitored and the concentrations of blood glucose were determined. The levels of glycogen and protein in liver were also measured. The plasma levels of cholesterol, triglyceride (TG), and fee fatty acid(FFA) were also analysed. The body weight gain was higher in the $H_2O$ group than in the control group. Heart weight was significantly reduced by administrations of Dioscorea japonica Thunb. The extents of blood glucose decrement in BuOH and $H_2O$ group were greater than that found in the control group. The muscle protein levels showed significantly higher amounts in all experimental groups. Glycogen levels were higher in the BuOH group than in the control group. The levels of TG were decreased in all experimental groups and the levels of plasma FFA were lower in the BuOH group. The plasma cholesterol levels were not influenced by these four fractions in diabetic rats. These results suggest that the orally administered H2O fraction of Dioscorea japonica Thunb exhibited hypoglycemic effects in STZ induced diabetic rats. (Korean J Nutrition 31(7) : 1093-1099, 1998)

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.595-602
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• 2023

The EAST ICRF system operating space has been extended in power and phase control with a low-level RF system for the new double-strap antenna. Then the multi-step power and periodic phase scanning experiment were conducted in L-mode plasma, respectively. In the power scanning experiment, the stored energy, radiation power, plasma impedance and the antenna's temperature all have positive responses during the short ramp-ups of P_L;ICRF. The core ion temperature increased from 1 keV to 1.5 keV and the core heating area expanded from |Z| ≤ 5 cm to |Z| ≤ 10 cm during the injection of ICRF waves. In the phasing scanning experiment, in addition to the same conclusions as the previous relatively phasing scanning experiment, the superposition effect of the fluctuation of stored energy, radiation power and neutron yield caused by phasing change with dual antenna, resulting in the amplitude and phase shift, was also observed. The active control of RF output facilitates the precise control of plasma profiles and greatly benefits future experimental exploration.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1064-1069
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• 2014

The use of emulsified fuel and EGR (Exhaust gas recirculation) system are effective methods to reduce NOx emission from diesel engines. In general, it is considered that EGR method influences diesel engine combustion in three different ways: thermal, chemical and dilution effect. Among others, the thermal effect is related to the increase of specific heat capacity due to the presence of $CO_2$ and $H_2O$ in inlet air. Meanwhile, emulsified fuel method of utilizing latent heat of vaporization and miro-explosion has been recognized as an effective technique for reducing diesel engine emissions. In this paper, an author studied on combustion and emission characteristics by using emulsified fuel (EF, Light oil : 80% + Water : 20%) and EGR (30% EGR ratio) system. And the effect of fuel injection pattern control was investigated.

• Journal of the Korean Society of Safety
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• v.37 no.5
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• pp.80-88
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• 2022

The Korean nuclear industry had developed the SPACE (Safety and Performance Analysis Code for nuclear power plants) code, which adopts a two-fluid, three-field model that is comprised of gas, continuous liquid and droplet fields and has the capability to simulate three-dimensional models. According to the revised law by the Nuclear Safety and Security Commission (NSSC) in Korea, the multiple failure accidents that must be considered for the accident management plan of a nuclear power plant was determined based on the lessons learned from the Fukushima accident. Generally, to improve the reliability of the calculation results of a safety analysis code, verification is required for the separate and integral effect experiments. Therefore, the goal of this work is to verify the calculation capability of the SPACE code for multiple failure accidents. For this purpose, an experiment was conducted to simulate a Control Element Drive Mechanism (CEDM) break with a safety injection failure using the ATLAS test facility, which is operated by Korea Atomic Energy Research Institute (KAERI). This experiment focused on the comparison between the experiment results and code calculation results to verify the performance of the SPACE code. The results of the overall system transient response using the SPACE code showed similar trends with the experimental results for parameters such as the system pressure, mass flow rate, and collapsed water level in component. In conclusion, it can be concluded that the SPACE code has sufficient capability to simulate a CEDM break with a safety injection failure accident.

• Nuclear Engineering and Technology
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• v.35 no.3
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• pp.226-233
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• 2003

The discharge characteristics of a prototype ion source was investigated, which was developed and upgraded for the NBI (Neutral Beam Injection) heating system of KSTAR (Korea Superconducting Tokamak Advanced Research). The ion source was designed for the arc discharge of magnetic bucket chamber with multi-pole cusp fields. The ion source was discharged by the emission-limited mode with the control of filament heating voltage. The maximum ion density was 4 times larger than the previous discharge controlled by a space-charge-limited mode with fully heated filament. The plasma (ion) density and arc current were proportional to the filament voltage, but the discharge efficiency was inversely proportional to the operating pressure of hydrogen gas. The maximum ion density and arc current were obtained with constant arc voltage ($80{\sim}100V$), as $8{\times}10^{11}cm^{-3}$ and 1200 A, respectively. The estimated maximum beam current was about 35 A, extracted by the accelerating voltage of 80kV.

• Advances in Energy Research
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• v.8 no.3
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• pp.175-184
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• 2022

The dual-fuel technology, which uses gaseous fuel as the main fuel and liquid as the pilot fuel, is an appealing technology for reducing the exhaust emissions. The current study proposes emission models based on ANFIS for a dual-fuel using producer gas (PG)-diesel engine. Emissions measurements were taken at different engine load levels and fuel injection timings. The proposed model predictions were examined using statistical methods. With R2 values in the range of 0.9903 to 0.9951, the established ANFIS model was found to be consistently robust in predicting emission characteristics. The mean absolute percentage deviate in range 1.9 to 4.6%, and mean squared error varies in range 0.0018 to 13.9%. The evaluation of the ANFIS model developed shows a reliable claim of intrinsic sensitivity, strength, and outstanding generalization. The presented meta-model can be used to simulate the engine's operation in order to create an efficient control tool.

• Korean journal of food and cookery science
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• v.16 no.6
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• pp.644-651
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• 2000

This study was carried out to evaluate the effects of fractions of methanol(MeOH) extracts of Lycopus lucidic Turcz on hyperglycemia and energy metabolites in streptozotocin(STZ) diabetic rats. Diabetes mellitus was induced in male Sprague-Dawley rats weighing 200-220 g by an injection of STZ dissolved in a citrate buffer into the tail vein at a dose of 45 mg/kg of body weight, and the rats were divided into 7 groups, that is, one normal group and 6 diabetic groups: STZ-control, hexane, chloroform(CHCl$\sub$3/). ethylacetate(EtOAc), butanol(BuOH) and H$\sub$2/O fraction-fed groups. All groups were fed an AIN-93 diet and the fractions of Lycopus lucidic Turcz were administered orally with 2 % Tween 80 for 14 days after the STZ injection. Body weight, diet intake and organ weights were monitored. The plasma levels of blood glucose, insulin and protein were determined. The plasma concentrations of cholesterol, HDL-cholesterol, triglycerides and free fatty acid were assayed. The plasma activities of aspartate aminotransferase (AST) and alanine aminotransferase(ALT) were also measured. Body weight losses were observed by feeding the fractions of Lycopus lucidic Turcz in STZ experimental groups, and the kidney weight was increased. The extent of blood glucose decrement was significantly greater in the hexane and BuOH fraction-fed groups than STZ-control group. The plasma protein level was significantly lower in the H$\sub$2/O fraction-fed group. The plasma cholesterol level was decreased in BuOH and H$\sub$2/O fraction-fed groups compared with the STZ-control group. The levels of free fatty acids in the CHC1$\sub$3/ and H$\sub$2/O fraction-fed groups were significantly decreased(p<0.05). ALT activitiy of BuOH fraction-fed group was lower than control but it was not significantly different. These results suggest that the fractions of Lycopus lucidic Turcz are capable of lowering blood glucose and fat metabolites concentrations when administered to STZ-treated rats, and AST/ALT activity and insulin levels show the possibility of therapeutic use to diabetes mellitus.