• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.2
• /
• pp.148-154
• /
• 2005

As the exciting point of each phase is determined by the position of rotor, the rotor's accurate position-information is needed for the Switched Reluctance Motor(SRM). When using an absolute-encoder or a resolver, to detect the location of rotor the initial starting is possible, as early sensing of rotor's location is possible. However, this is not appropriate, considering the economical efficiency, and in case of using the incremental-encoder, there's a problem at initial starting as it is not easy to track down the location of rotor at the very beginning. When using Hall-ICs, there's a fault, as it needs a special ring magnet. Considering the initial starting and economical efficiency, the optical sensor technique using a slotted-disk and an opto-interrupter is appropriate, however, this method needs three opto-interrupters and a slotted-disk when using the 6/4 pole SRM. Nevertheless, in this paper, it used only two optical sensors to operate 6/4 pole SRM and made the start up and also forward and reverse operation possible. By excluding the slotted-disc md shortening a optical sensor, it improved the convenience and economical efficiency of the production. Also, as the space for slotted-disc is no more needed, it was able to reduce the size of motor.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.7
• /
• pp.531-540
• /
• 2009

In this study, thermo-gravimetric analysis(TGA) was used to investigate the effect of urea concentration and heating rate on the ammonia($NH_3$) formation process from urea solution. A newly designed pipe nozzle was inserted through a 1,000 N${\ss}$(C)/h oil firing boiler to compare the DeNOx efficiencies between the upward and downward nozzle. This experiment reveals the effect of path which an urea droplet goes through. Urea solution showed the same TGA graph without regard to the presence of oxygen. Heating rate had a great influence on the weight loss trend. But the concentration of urea solution between 10% and 40% did not affect so much the thermal decomposition temperature. Therefore, heating rate is more important factor on the thermal decomposition of urea than the concentration of urea solution. Three nozzles located at different positions showed similar DeNOx efficiencies such as 68.1%, 71.8%, 70.8% at the same temperature. Even though urea solution was injected for the same zone, the injection direction made much difference in DeNOx efficiency. A upward nozzle showed 68.1% and downward nozzle 9.5%. This results illustrate the importance of heating rate.

• Journal of Surface Science and Engineering
• /
• v.39 no.4
• /
• pp.179-189
• /
• 2006

High velocity oxygen fuel(HVOF) thermal spray coating of WC-Co powder is one of the most promising candidate for the replacement of the traditional hard chrome plating and ceramics coating because of the environmental problem of the very toxic $Cr^{6+}$ known as carcinogen and the brittleness of ceramics coating. WC-Co micron and nano powder were coated by HVOF thermal spraying method for the study of durability improvement of the high speed spindle. Coatings were planned by Taguchi program for the four spray parameters of spray distance, flow rates of hydrogen, oxygen and powder feed rate. Optimal coating process was obtained by the studies of coating properties such as porosity, surface roughness, micro hardness, and micro structure. WC-Co micron and nano powder were coated on the Inconel 718 substrate by the optimal coating process obtained in this study. The wear behaviors were studied by the sliding wear tester at room temperature and at an elevated temperature of $500^{\circ}C$ for the application to high speed spindle. Sliding wear test was carried out for four most promising hard coatings of chrome coating, ceramics coatings such as $A1_2O_3,\;Cr_2O_3$ and HVOF Co-alloy T800 for the comparison of their wear behaviors. HVOF WC-Co coating was better than other coatings showing highest micro hardness of 1400 Hv and comparable friction coefficients with others. HVOF WC-Co coating is a strong candidate for the replacement of the traditional hard chrome plating for the high speed spindle.

• Journal of Veterinary Clinics
• /
• v.15 no.1
• /
• pp.62-74
• /
• 1998

In feedlot cattle the abrupt change of diet from roughage to a large quantity of grain for the purpose to improve production often results in increased occurrence of rumen acidosis or acute carbohydrate encouragement enterotoxemia, bloats diarrhea liver abscess and laminitis or robot disease. The common management practice to control these problem is to increase the amount of concentrates in the diet in a stepwise manner until the animals are adapted to a high-grain ration. However this practice requires at least about 3 weeks adaptation period and specially prepared adaptation rations which contain various amount of concentrates. Present experiment was undertaken in order to findout the more simple and rapid adaptation method of cattle to a high grain ration. Nineteen Korean calves aging from four to six month were fed artifical hay (Youngchoun Chuk-Hyup, Korea) which contains 10% of concentrates or alfalfa and rye grass hays for two months and randomly alloted to three experimental groups and two control groups. The experimental group-1 was inoculated by stomach tube for two days with li500 ml/day of ruminal fluid fished from Korean beef cattle that had been previously adapted to a high-energy ration. The experimental group-2 was inoculated by trocalization for two days with the same ruminal fluid. The experimental group-3 was inoculated by trocalization with 1,500 ml/day of bacterial culture which contained 2$\times $10$^{9}$/m1 of Gram-negative bacteria derived from adapted luminal fluid. The two control groups were treated with normal saline solution by the same methods. All animals were fed high-energy ration that contained 80% of grain ad libitum for 30-74 days beginning on the third of the treatment. The effect of the inoculation on the adaptation was observed clinicopathologically with the following results; All of the experimental calves inoculated with the ruminal fluid or Gram-negative bacterial culture derived from adapted cattle did not show any signs of rumen acidosis or other related diseases, while most of the control calves did show diarrhea and bloat and a calf laminitis. The average daily weight gain and feed efficiency of experimental calves were slightly improved compared with control calves. Following the feeding of high-grain rational the pH of the ruminal fluid was lowered in both the experimental and control groups. However severe acidosis with the pH of below 5.0 was observed in only a control group-2. The protozoal number in ruminal fluid was markedly decreased during the high-grain feeding in both the experimental and control calves. However the decrease was mere severe in control calves compared with the experimental calves. The activation of the protozoa were completely disappeared within nine hours at the refrigerator temperature (4"C). No significant differences in heamatological and blood chemical values between the experimental and control calves were recognized. However in one control calf which showed clinically laminitis marked elevations of serum glutamic oxaloacetate transaminase and lactic dehydrogenase activities and a decrease of serum glucose level were observed. From these results it would be concluded the intraruminal transplantation of unadapted calves with the adapted ruminal fluid from cattle previously adapted to a high-energy ration prevents disease problem associated with high-grain feeding and improve weight gain and feed efficiency.ency.

• Journal of Veterinary Clinics
• /
• v.12 no.1
• /
• pp.877-886
• /
• 1995

The recycling nuclear transplantation(NT) technique has the powerful potential of producing a large number of genetically identical embryos and offsprings from one embryo. Multiple generational cloning by this technique utilizes the NT embryo itself as the donor for the next generation of cloning. In this experiment, we have produced the third generational cloned embryos by recycling NT. Further we examined comparatively the electrofusion rate and in vitro developmental potential in the cloned embryos of the first second and third generations. The embryos of 16-cell stage were collected from the mated does by flushing oviducts with Dulberco's phosphate buffered saline containing 10 % fetal calf serum(FCS) at 47 hours after hCG injection. In the first generation NT, the nuclear donor embryos were synchronized in the phase of Gl/S transition of 32-cell stage. The first and second generation NT embryos developed to 16-cell were used as donor nuclei for second and third generation. The recipient cytoplasms were utilized the oocytes collected at 14 hours after hCG injection, following revoming the nucleus and the first polar body by micromanipulation. The separated blastomeres were injected into the enucleated recipient oocytes by micromanipulation and were fused by electrical stimulation. The electrofusion rate was seen to be 78.0, 88.0 and 90.3 % in the first second and third generation NT rabbit embryos, respectively. The fused oocytes were co-cultured with a monolayer of rabbit oviductal epithelial cells in M-199 solution containing 10 % FCS for 120 hours at 39$^{\circ}C$ in a 5% $CO_2$ incubator. The in vitro developmental potential to blastocyst stage was significantly(P<0.05) decreased in the third(7.2 %) generation NT embryos compared to the first(53.1 %) and second(16.1 %) generation NT embryos. Following in vitro development to blastocyst stage, they were stained with Hoechst 33342 dye for counting the number of blastomeres by fluorescence microscopy. The mean blastomere numbers and cell cycle numbers of NT embryos during the culture period were significantly(p<0.05) decreased in the second(93.9 cells and 6.55 cylces) and third(81.5 cells and 1.35 cylces) generation, compared to the first(189.9 cells and 7.55 cylces) generation.

• Weed & Turfgrass Science
• /
• v.5 no.4
• /
• pp.241-246
• /
• 2016

This study was conducted to examine the effects of Glycine soja (GS) supplementation on the quality of corn silage. Corn silage was used in a $3{\times}2$ factorial arrangements with respective factors being addition of GS (0, 10, and 20%) and without or with Lacobacillus plantarum as lactic acid bacteria, and were stored for 40 days at a room temperature ($20-25^{\circ}C$). Corn silage with supplemented 20% GS increased (p<0.05) crude protein contents compared with that in corn silage with supplemented 0 and 10% GS, however crude fat, NDF, and starch concentrations was not affected (p<0.05) by addition of GS. Furthermore, the interaction was found (p<0.05) between corn silage with supplemented 20% GS and the addition of lactic acid in butyric acid. Silage pH was increased while GS supplementation increased. Corn silage with supplemented 20% GS increased (p<0.05) glucose and fructose concentrations. The results of current study indicate that corn silage with supplemented 20% GS could be used as a useful strategy to improve corn silage with increased crude protein contents along with sucrose, glucose and fructose concentrations.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.23 no.3
• /
• pp.27-27
• /
• 1987

The purpose of this study is to find the light intensity which induced maximum gathering rate and to observe the variation of the gathering rate both at daytime and night by using Sea-bass, Epinephelus septemfasciatus (Thunberg). An experimental tank (360 L×50 W×55H cm) was set up in a dark room. An illumination system was attached to the end of one side of the tank to control horizontal light intensity. Eight artificial light sources were prepared by combination of three with white light bulbs (10W, 60W, 100W) and eight filters. During the experiment water depth was maintained 50cm level in the tank. The tank was marked into six longitudinal sections each being 60cm long to observe the distribution of fish. The fish were acclimatized in dark condition for 50 minutes before the main experiment. Upon turning on the light, the number of fish in each section was counted 60 times every 30 seconds, and the gathering rate was obtained from the average number of fish in each section. The light intensity inducing maximum gathering rate was 24.13 lux (15.25~35.93 lux) at daytime and 0.41 lux (0.25~0.63 lux) at night. The variation of the gathering rate of fish in illumination time was great and did not show any definite pattern but fluctuated irregularly. Its different between daytime and night is remarkable.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.23 no.3
• /
• pp.137-143
• /
• 1987

The purpose of this study is to find the light intensity which induced maximum gathering rate and to observe the variation of the gathering rate both at daytime and night by using Sea-bass, Epinephelus septemfasciatus (Thunberg). An experimental tank (360 L$\times$50 W$\times$55H cm) was set up in a dark room. An illumination system was attached to the end of one side of the tank to control horizontal light intensity. Eight artificial light sources were prepared by combination of three with white light bulbs (10W, 60W, 100W) and eight filters. During the experiment water depth was maintained 50cm level in the tank. The tank was marked into six longitudinal sections each being 60cm long to observe the distribution of fish. The fish were acclimatized in dark condition for 50 minutes before the main experiment. Upon turning on the light, the number of fish in each section was counted 60 times every 30 seconds, and the gathering rate was obtained from the average number of fish in each section. The light intensity inducing maximum gathering rate was 24.13 lux (15.25~35.93 lux) at daytime and 0.41 lux (0.25~0.63 lux) at night. The variation of the gathering rate of fish in illumination time was great and did not show any definite pattern but fluctuated irregularly. Its different between daytime and night is remarkable.

• Korean Journal of Food Science and Technology
• /
• v.34 no.6
• /
• pp.1091-1097
• /
• 2002

In order to improve palatability and quality of traditional kochujang, kiwifruit (Actinidia deliciosa) was added to traditional kochujang fermented for 3 months. Physicochemical and microbial characteristics were investigated during fermentation at $30^{\circ}C$. Moisture contents of all treated kochujangs increased with increasing amount of kiwifruit added during fermentation. pH of kiwifruit-added kochujang was lower than that of the control kochujang, whereas no significant differences in titratible acidity was observed among all treatments. Crude protein and salt contents of kiwifruit-added kochujang were lower than those of the control, whereas no difference in crude fat contents were found. Ethanol and amino-nitrogen contents of 6 and 9% kiwifruit-added kochujang were higher than those of the control. Fructose contents of kiwi-added kochujangs were higher than that of the control. Major organic acids of kochujang were in the order of malic acid > citric acid > succinic acid > acetic acid > lactic acid > oxalic acid. Succinic acid level increased significantly during fermentation and was higher in kiwifruit-added kochujang than in the control. Bacterial cell counts of all treatments were not different, and viable cell count of yeast was slightly higher in kiwifruit-added kochujang only at the initial fermentation period. Sensory evaluation revealed that the addition of 9% kiwifruit was the optimum condition for improving kochujang quality.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.11
• /
• pp.5094-5101
• /
• 2011

In order to investigate recurrence rate and risk factors for recurrence of gastric cancer after curative resection, we examined blood biochemical profile and clinicopathological features of 386 gastric cancer patients by using medical charts and data of hospital cancer registry from September 2010 to May 2011. Chi-square test and logistic regression analyses were performed to identify risk factors. The recurrence rate of all gastric cancer patients was 2.6%; The recurrence rate by gender was 3.45% in male and 0.89% in female, and that was 4 times higher in male than in female. On univariate logistic regression analyses, lymph node metastases(OR=8.793), Helicobactor pylori infecton(OR=6.495), abnormal total cholesterol(OR=14.333) were related to recurrence. On multivariate logistic regression analyses, lymph node metastases and H. pylori infection were very important risk factors for recurrence of gastric cancer. In conclusion, lymph node metastases, H. pylori infection, and total cholesterol control were very important to prevent recurrence of gastric cancer, and it needs to monitor blood biochemical (C-reactive protein, carcinoembryonic antigen, etc) for the early detection of gastric cancer recurrence.