• Korean Journal of Agricultural Science
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• v.20 no.2
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• pp.167-180
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• 1993

Most of small size diesel engines are widely used with the same size and weight flywheel in the levels of 6.0kW and 7.5kW. This study was conducted to obtain basic data which affect the engine performance of the power tiller. The flywheel weight was considered as a major factor in this research. Basically, fuel consumption ratio, motoring loss, torque, vibration and mechanical efficiency of the engine were measured and analyzed on four levels of flywheel weight, 32.2, 29.4, 26.2 and $24.2kg_f$, respectively. Results were obtained as follows: 1. The weights of flywheel were $23.7kg_f$ from design program of JSME and $24.5kg_f$ from ASME and SAE design criteria. Therefore, the flywheel weight of $32.2kg_f$ might be reduced about $8kg_f$ in 7.5kW engine. 2. The rated outputs of 6.0kW and 7.5kW engine were actually 7.43kW and 7.85kW, respectively. When flywheel weight was reduced from $32.2kg_f$ to $24.2kg_f$, outputs were increased from 7.43kW to 7.70kW in 6.0kW engine and from 7.85kW to 8.25kW in 7.5kW engine. 3. When the flywheel weight was reduced from $32.2kg_f$ to $24.2kg_f$, fuel consumption ratio was decreased from 300.8 to 296.8g/kW-hr in 6.0kW engine and also from 313.6 to 312.8g/kW-hr in 7.5 kW engine, respectively. 4. When the flywheel weight was reduced from $32.2kg_f$ to $24.2kg_f$, mechanical efficiency of engine was increased from 76.1% to 76.8% in 6.0kW engine and also from 76.7% to 77.0% in 7.5kW engine, respectively. 5. When the flywheel weight was reduced from $32.2kg_f$ to $24.2kg_f$, vibration was decreased at X-axis and Z-axis in 6.0kW engine, however, slightly increased at Y-axis in 6.0kW engine and at all axes in 7.5kW engine. 6. When the flywheel weight was reduced from $32.2kg_f$ to $24.4kg_f$ motoring loss was decreased from 2.33kW to 1.75kW in 6.0kW engine and also from 2.46kW to 1.84kW in 7.5kW engine.

• Korean Journal of Agricultural Science
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• v.15 no.2
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• pp.143-152
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• 1988

This study was conducted to obtain basic data which affected engine performance of the power tiller being widely used in the rural area. Among the various factors affected engine performance, only flywheel weight was considered as the major factor in this study. Fuel consumption ratio, motoring loss, torque, vibration and mechanical efficiency of the engine tested were measured and analyzed on the four levels of flywheel weight (32.2, 29.7, 26.4, 24.2 kg). The results obtained were as follows: 1. The maximum output of 6 and 7.5 kW engine was 7.43 kW and 7.85 kW respectively. When flywheel weight was reduced from 32.2 kg to 24.2 kg, output power of the engine was increased 0.27 kW in 6 kW engine and increased 0.39 kW in 7.5 kW engine. 2. The fuel consumption ratio was decreased from 300.8 to 296.8 g/kW-hr in 6 kW engine and decreased from 313.6 to 312.8 g/kW-hr in 7.5 kW engine when the flywheel weight was reduced from 32.2 kg to 24.2 kg. 3. The mechanical efficiencies of the engine was increased from 76.1 to 76.8% in 6 kW engine and increased from 76.7 to 77.0% in 7.5 kW engine when the flywheel weight was reduced from 32.2 kg to 24.2 kg. 4. When the flywheel weight was reduced from 32.2 kg to 24.2 kg, a tendency of a little decrease of vibration at X- and Z-axis in 6 kW engine and of a little increase of vibration at Y-axis in 6 kW engine and all directions in 7.5 kW engine was observed. 5. Motoring losses was decreased from 2.33 to l.76 kW in 6 kW engine and decreased from 2.46 to 1.84 kW in 7.5 kW engine when the flywheel weight was reduced from 32.2 kg to 24.2 kg. From the above results and the flywheel weight calculated theoretically, it was recommendable that the flywheel weight should be reduced about 7 kg in 6 kW engine and about 10 kg in 7.5 kW engine, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1301-1307
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• 2008

In this paper, we developed UHF RFID R/W system using AT91SAM7S256(ARM chip), UHF RFID R/W module (WJ7090) and wireless LAN(IEEE 802.11.a/b). And we developed a transmission/receiving packet which is send to UHF R/W module in AT91SAM7S256. In order to show the usefulness of UHF RFID R/W system, we executed a performance test. The developed UHF RFID R/W system shows better performance for reading of RFID tag and data transmission through wireless LAN.

• Fisheries and Aquatic Sciences
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• v.16 no.1
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• pp.57-61
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• 2013

I hypothesized that the manipulation of dietary nutrient contents including phosphorous could affect compensatory growth of juvenile olive flounder, Paralichthys olivaceus. Thirty fish averaging 34.8 g per tank were randomly chosen and distributed into 15 flow-through 180-L tanks. Three experimental diets were prepared: the control (C) diet, high protein and lipid (HPL) diet, and HPL diet with supplementation of calcium phosphate-monobasic (HPLP). Five treatments were prepared in triplicate: fish were hand-fed daily with the C diet twice a day for 8 weeks (C-8W); fish were starved for 1 week, and then fed with the HPL or HPLP diets twice a day for 7 weeks, and referred to as HPL-7W and HPLP-7W, respectively; and fish were starved for 2 weeks, and then fed with the HPL or HPLP diets twice a day for 6 weeks, and referred to as HPL-6W and HPLP-6W, respectively. The body weight of fish with C-8W, HPL-7W and HPLP-7W treatments was higher than fish with HPL-6W and HPLP-6W treatments on week 2, 4 and 6 after an initiation of the trial. At the end of the 8-week trial, fish with HPLP-7W and HPL-7W treatments overcompensated, as compared to fish with C-8W treatment. Full compensation was not achieved in fish subjected to the 2-week feed deprivation (HPL-6W and HPLP-6W treatments). Overall feed intake by fish was proportional to weeks of feeding. Feed conversion ratio of fish with HPLP-7W, HPL-6W and HPLP-6W treatments was higher than fish with C-8W treatment. The study showed that dietary supplementation of protein and lipid resulted in overcompensation of juvenile olive flounder subjected to a 1-week feed deprivation, but not a 2-week feed deprivation. Additionally, dietary supplementation of phosphorous did not further improve compensatory growth of fish.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.170-179
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• 2012

We examined pretreatment methods eliminating potassium and sodium efficiently for coir bag used in hydroponics by analyzing drainage coming from coir bags. In the first experiment we investigated for six coir bags with the high market shares. The three types of pretreatment were washing coir bags with only water for 7 days (W7S0), washing with water for 4 days and further with nutrient solution for 3 days (W4S3), and washing with only nutrient solution for 7 days (W0S7). In the second experiment we tested reproducibility of the experiment results for Bio Grow and coco Mix among six coir bags used in the first experiment to verify the results. As a result, the best pretreatments for the pH stabilization were W4S3 and W0S7. The EC value of the drainage was stabilized to less than 1.0 that is the same as EC of the supply solution on the fourth day in all treatments. The nutrients of the drainage in W7S0 was stabilized in 3~4 days but calcium and magnesium were depleted. We assessed that washing longer than 4 days was waste of water. The stabilization of coir bags in W0S7 was similar to it in W4S3, but washing with the nutrient solution for 7 days seemed to be uneconomical. The reproducibility experiment for two coir bags ensured the results in the first experiment. Therefore, the pretreatment method, which is the most simple to implement and economic, seems to wash with water for 3 days and then with the nutrient solution for 1 day before planting on coir bag.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.5
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• pp.499-506
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• 2019

This paper is concerned with the operating stability of 7kW inverter using SIC hybrid module and verifies the validity of the simulation results by comparing the result of the loss equation and the simulation result, Simulation results using Si module and SiC hybrid module are compared to compare switch loss and diode loss. Through the loss equation calculation, the conduction loss of SiC Hybrid module is 168W, switching loss is 9.3W, diode loss is 10.5nW, When compared with the simulation results, similar values were shown. As a result of comparing the simulation results of the Si module and the SiC Hybrid module, The total device loss of the Si module was 246.2W, and the total device loss of the SiC Hybrid module was 189.9W. The loss difference was 56.3W, which was about 0.8W. thereby verifying the reverse recovery characteristics of the SiC SBD. In addition, temperature saturation test was conducted to confirm the stability of SiC Hybrid module and Si module under high temperature saturation, In the case of the Si module, the output power was stopped at 4kW, and the SiC Hybrid module was confirmed to operate at 7kW. Based on this, an efficiency graph and a temperature graph are presented, and the Si module is graphed up to 4kW and the SiC Hybrid module is graphed up to 7kW.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1540-1544
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• 2003

This study chiefly aimed to ascertain the effect of age at weaning on caecal content characteristics, post-weaning performance and health of rabbits. A secondary aim was to study the effect of dietary restriction on performance and health of rabbits. After delivery, 30 litters of 8 pups each, were housed in separate cages. Fifteen litters were weaned 24 days from birth (group W 24) while the other 15 were weaned at 28 days (group W28). After weaning, 53 rabbits of group W24 and 56 of group W28 were fed ad libitum (group LIB), while 53 rabbits of group W24 and 57 of group W28 were restricted (group RES). All the rabbits were kept in individual cages. Fourteen other rabbits of groups W24 (7 fed ad libitum and 7 restricted) and 7 of group W28 were sacrificed to obtain data regarding caecum weight and caecal content. Age at weaning affected neither the state of health nor the final live weight. In comparison with those of group W28, the rabbits weaned at 24 days had a lower daily gain until 35 days of age but gain was higher subsequently. From the 28th day, however, the feed intake and the feed conversion ratio of the group W24 rabbits were always better than those of W28. The restricted diet until 42 days resulted in a lower weight both at 42 days (1,078 vs. 1,164 g) and at 70 days (2,192 vs. 2,294 g). Indeed, from the 42nd day, despite receiving feed ad libitum the rabbits of the restricted group continued to ingest less feed (120.8 vs. 127.2 g) than those of the ad libitum group, and had a slightly lower daily gain (39.8 vs. 40.3 g). The measurements carried out on the caecum highlighted significant differences among the groups in caecal content (33.1 vs. 31.7 vs. 25.3 g respectively for groups W24LIB, W28 and W24RES), for total volatile fatty acids (53.2 vs. 50.6 vs. 44.5 mmol/l respectively for groups W24LIB, W28and W24RES) for ammonia (7.0 vs. 7.2vs 8.8 mmol/l respectively for groups W24LIB, W28 and W24RES), for propionate (5.7 vs. 6.3 vs. 8.1% respectively for groups W24LIB, W28 and W24RES) and for propionate/butyrate (0.33 vs. 0.36 vs. 0.49 respectively for groups W24LIB, W28 and W24RES).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.4
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• pp.187-192
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• 2023

This paper deposited CdTe thin films on ITO glass substrates using sputtering equipment while changing RF power. As a result of measuring the thickness of the thin film, 1481Å at 100W, 2985Å at 150W, and 4684Å at 200W. And the mobility was measured as 8.43 cm2/Vs for 100W, 7.91 cm2/Vs for 150W, and 6.57 cm2/Vs for 200W. It can be seen that the thickness and mobility of the thin film are inversely proportional. As a result of confirming the transmittance, the transmittance was 84% at 905nm for 100W, the transmittance was 71% at 825nm for 150W, and 77% at 874nm for 200W. At 100 W, the thickness of the thin film was thin, so the transmittance was measured to be high. In other words, the correlation between transmittance and thickness can be seen. As a result of measuring the FHWM and particle size by changing the RF Power, 100W was calculated as 0.18, 150W was calculated as 0.19, and 200W was calculated as 0.73. The size of the particles was formed at 8.47Å at 100W, 7.98Å at 150W, and 8.7Å, which is the largest at 200W. In conclusion, it was found that the FHWM and particle size were inversely proportional.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.16-20
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• 2002

In this study, the 95W heavy alloys of 3/7, 5/5 and 7/3 of Ni/Fe ratio were sintered at the temperature range between 1420 and $1480^{\circ}C$ for 1h and their microstructures were discussed for an effect of the ${\mu}$-phase $(Fe_7W_6)$ on the microstructure. The ${\mu}$-phase was observed in the only 95W-1.5Ni-3.5Fe alloy of 3/7 and it is thought to be formed and grown from the surface of the W particle. The W particle was surrounded with the ${\mu}$-phase and there were only the W particles and this phase without Ni-Fe-W matrix at the most part. The ${\mu}$-phase changed the interphase structure in the alloy and the grain growth of the W was suppressed because of interrupting the solution-reprecipitation of the W. The W content in the matrix was considered to be lowered due to the interruption of the solution-reprecipitation and the formation of the ${\mu}$-phase in the .

• Korean Journal of Acupuncture
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• v.23 no.1
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• pp.1-14
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• 2006

Objectives : This research was performed to investigate the effect of invasive low level laser acupuncture therapy(LLLAT) at Yolgyol+yogu(LU7+LR5) on weight gain, food intake, food efficiency, lipid metabolism and liver function in hyperlipemia rats. Methods : Experimental groups were divided into high fat diet cup(Control group), high fat diet and 15 mW/5 min LLLAT at LU7+LR5(15 mW/5 min group), 15 mW/10 min LLLAT at LU7+LR5(15 mW/10 min group), 30 mW/5 min LLLAT at LU7+LRS(30 mW/5 min group), 30 mW/10 min LLLAT at LU7+LR5(30 mW/10 min group). LLLAT was treated at the 15,30mW-5,10min once a 2day during 5 weeks. Results : Body weight was decreased significantly in 30 mW/s min group and 30 mW/10 min group compared with control group. Food intake was decreased significantly in 15 mW/5 min group and 15 mW/10 min group compared with control group. Food efficiency was decreased significantly in 30 mW/10 min group compared with control group. In the lipid metabolism, total cholesterol, HDL-cholesterol and free fatty acid were increased significantly in 15 mW/5 min group and 30 mW/10 min group compared with control group. LDL-cholesterol was increased in 30 mW/10 min group and phospholipids was decreased significantly in all experimental group compared with control group. triglyceride was not showed significant result in all experimental group. In the liver function, AST was not showed significant result in all experimental group, ALT and ALP were increased significantly in 30 mW/10 min group, ALP was decreased in 30 mW/5 min group compared with control group. Conclusions : LLLAT at LU7 and LR5 can manage hyperlipemia by controlling body weight, food intake, food efficiency ratio and lipid metabolism.