• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.120-126
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• 2002

The needs of ultra-precisely machined parts are increasing more and more. But the experimental data required to ultra precision machining of nonferrous metal is insufficient. The behavior of cutting in micro cutting area is different from that of traditional cutting because of the size effect. Copper is widely used as optical parts such as LASER reflector's mirror and multimedia instrument. In experimental, after oxygen-free copper is machined by ultra precision machine with natural mono crystal diamond tool (NCD) and synthetic poly crystal diamond tool (PCD), we compared chip formation and tool's wear according to used tool. Also, we researched optimized cutting condition with the results measured according to cutting condition such as spindle speed, feed rate and depth of cut. As a result, the optimal working condition that makes good surface roughness is obtained. The surface roughness is good when spindle speed is above 80 m/min, and feed rate is small and depth of cut is above 0.5 ${\mu}{\textrm}{m}$. In cutting of klystron anode and cavity 3.2 nmRa of surface roughness is obtained.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.83-88
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• 2003

In this study, experiments were conducted with an ultra-precision machine, developed In domestic, to find the characteristics and the most suitable cutting conditions of ultra-precision machining. To maximize the performance of the machine, the machine was installed in a room that is protected from vibration and is maintained constant temperature and constant humidity. Selected work pieces are an aluminum-alloyed material, which has excellent corrosion resistance and has low deformation. The used tool is synthetic poly crystal diamond which has excellent abrasion resistance and has low affinity. Four types of tool nose radius were used such as 0, 0.1, 0.2 and 0.4mm. Machining is performed with cutting speed of 500, 800 and 1000m/min., feed rate of 0.005, 0.008, 0.010mm/rev. and cutting depth of 0.0005, 0.0025 and 0.005mm respectively which can generally be used in the field as a cutting condition. As a method of evaluation surface roughness was measured for each cutting condition and reciprocal characteristics are computed for each tool nose radius, cutting speed, feed rate and cutting depth. As a result the most suitable cutting condition and characteristics of ultra-precision machining were identified which can usefully be applied in the industrial field.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.1
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• pp.9-15
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• 2004

In this study, experiments were conducted with an ultra-precision machine, developed in domestic, to find the characteristics and the most suitable cutting conditions of ultra-precision machining. To maximize the performance of the machine, the machine was installed in a room that is protected from vibration and is maintained constant temperature and constant humidity. Selected work pieces are an aluminum-alloyed material, which has excellent corrosion resistance and has low deformation. The used tool is synthetic poly crystal diamond, which has excellent abrasion resistance and has low affinity. Four types of tool nose radius were used such as 0, 0.1, 0.2 and 0.4mm. Machining is performed with cutting speed of 500, 800 and 1000m/min., feed rate of 0.005, 0.008, 0.010mm/rev. and cutting depth of 0.0005, 0.0025 and 0.005mm respectively which can generally be used in the field as a cutting condition. As a method of evaluation, surface roughness was measured for each cutting condition, and reciprocal characteristics are computed for each tool nose radius, cutting speed, feed rate and cutting depth. As a result, the most suitable cutting condition and characteristics of ultra-precision machining were identified which can usefully be applied in the industrial field.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.2
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• pp.280-287
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• 2001

These studies aimed to determine how lighting might be used to improve feed intake and reduce aggressive behavior in newly weaned pigs. To examine whether this objective could be achieved an experiment was conducted to compare performance, behavior and body condition of weaners over 17-45 days, provided similar lighting quality (i.e. color temperature, color rendering index and lighting distribution) after weaning that piglets experienced prior to weaning. Triphosphor (TP) lighting to simulate daylight was provided during the day while at night, Pascal red (PR) lighting was provided to simulate the night-light piglets previously had received from infrared heating lamps. This treatment was compared to weaners provided conventional cool-white fluorescent light during the day only. Weaners on treatment lighting from 17-45 days of age showed no improvement in body weight or feed conversion at 24, 31, 38 and 45 days compared to the controls. There was, however, a significant improvement (p<0.05) in feed intake in the first week of weaning for weaners provided TP/PR lighting. Over the first 3 days of weaning, pigs on TP/PR lighting showed an increase (p<0.05) in the incidence of ear chewing but reduced (p<0.05) levels of nosing the abdomen of other pigs and reduced (p<0.05) occurrences of being stood on by other pigs. Females exhibited more (p<0.05) mounting and nosing behaviors and rubbing the heads of other pigs than males. On the other hand, males engaged in more (p<0.05) fighting, nipping, ear chewing and standing on other pigs compared to females. Pigs provided PR lighting on the first night of weaning engaged in higher (p<0.05) incidences of nosing and tail sucking behaviors, more (p<0.05) head thrusting, fighting and ear chewing compared to control pigs. The body condition of weaners provided the TP/PR lighting treatment was significantly poorer (p<0.05) compared to weaners on control lighting. In conclusion there was no improvement in production performance of weaners provided new technology lighting apart from the improvement in feed intake in the first week weaners were exposed to the TP/PR lighting.

• Membrane Journal
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• v.26 no.1
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• pp.70-75
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• 2016

The reuse of wastewater is being diffused to manage and develop the water resources. Generally, the treated wastewater is discharged to the river after being treated to meet the effluent quality standard or reused for diverse uses through the reprocessing. And recently, as the reuse of the treated wastewater is activated, the technologies to utilize for the high quality water resources such as industrial water by reusing the wastewater with Membrane Distillation (MD) are under development. In this study, the direct contact membrane distillation (DCMD) process has been applied to treat sewage discharge water for water reuse. The laboratory scale experiment was performed by using a hydrophobic PVDF membrane with the pore size of $0.22{\mu}m$. The influence of operating parameters, such as feed temperature, feed flow rate, feed concentration, on the permeate flux and rejection has been investigated. All filtration tests were conducted till the feed volume reached a concentration factor of 3.0. Thus, the operating period ranged between 19 hr and 49 hr depending on filtration performance. The results showed that above 92% of TN, TP, COD and TOC in the feed could be rejected regardless of an operating condition. The water flux was ranged from 13.8 to 20.3 LMH. The lowest flux was obtained at the operating condition with the feed temperature of $50^{\circ}C$ and feed flow velocity of 500 mL/min while the highest one was measured with $60^{\circ}C$ and 900 mL/min. When the concentration factor reached 3.0, water flux declined by approximately ranged from 14.5% to 33.3%. But the fouling in MD is almost fully reversible, with more than 90% recovery of permeate water flux following a DI water rinse without the addition of chemical cleaning reagents.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.10
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• pp.1354-1363
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• 2010

This study compared the effect of four different feeding methods for gestating gilts on reproductive performance and growth of their progeny. A total of 40 F1 primiparous sows (Yorkshire${\times}$Landrace) were allotted to four treatments in a completely randomized design (CRD). For treatments, gestating period of sows was divided into three trimesters (0-35 d, 36-90 d and 91-110 d) and different amounts of feed were provided to each treatment group by Flat, Down-Up-Down (DUD), Up-Down-Up (UDU) and Down-Up-Up (DUU) feeding methods. The experimental diet was formulated to meet or exceed the standards of NRC (1998). Body weight gain of gestating gilts from d 0 to 110 was affected by feeding method (p<0.05). When gilts were fed constant feed ration (Flat feeding), less body weight loss was observed during lactation (-0.9 kg, p<0.05) and desirable backfat thickness (average 19.5 mm) was acquired at 110 days of gestation. Feed intake of lactating sows tended to be greater (4.22, 3.60, 3.97 and 4.13 kg/d, p>0.05) as sows in Flat feeding treatment had lower backfat thickness during gestation compared with other treatments (p<0.05). When gestating gilts were fed higher amount of feed during mid-trimester, the number of stillborn (1.4 piglet per litter, p<0.05) and mummies (0.8 piglet per litter, p = 0.25) were increased compared to other treatments. Feeding methods for gestating gilts had no effect on litter weight and gain of litter weight during the nursing period. Flat feeding method resulted in decreased plasma glucose concentration at 7 d postpartum (p<0.05), and increased LH concentration at 21 d postpartum (p<0.01) compared to other treatments. These results suggested that higher feed intake of gestating gilts resulted in detrimental effects on body condition and reproductive performance of sows. When gestating gilts consumed constant feed during gestation (2 kg/d), better reproductive performance and less body weight loss in lactation were observed because sows consumed more feed during the whole lactation period. Consequently, Flat feeding will be a desirable feeding strategy for gestating gilts to maximize reproductive performance, and better body condition of sows without any negative influence on the growth of their progeny.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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• pp.304-311
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• 2014

In this study, to apply hydrogen energy to ship engine and to generate effective hydrogen production, we investigated the effects of high temperature $H_2SO_4$ feed rate and cooling water rate to pump parts with fixed frequency needed to reciprocate motion and a simulation was conducted at each condition. In the fixed frequency and cooling water inlet flow rate of 0.5 Hz and 3.9 kg/s, we changed the high temperature $H_2SO_4$ flow rate to 47.46 kg/s (it is 105 % of 45.2 kg/s), 49.72 kg/s (110 %), and 51.98 kg/s (115 %). Also, at 0.5 Hz and 45.2 kg/s of frequency and high temperature $H_2SO_4$ flow, the thermal hydraulic analysis was performed at the condition of 95 % (3.705 kg/s), 90 % (3.51 kg/s), and 85 % (3.315 kg/s). In overall simulation cases, the physical properties of materials are more influential to the temperature increase in the pump part rather than the changes on the feed rate of high temperature $H_2SO_4$ and cooling water. A continuous operation of pump was also capable even if the excess feed of high temperature $H_2SO_4$ of about 15 % or the less feed of cooling water of about 15 % were performed, respectively. When the increasing feed of high temperature $H_2SO_4$ of up to 5 %, 10 %, and 15 % were compared with base flow (45.2 kg/s), the deviation of time period rose to a certain temperature and ranged from 0 to 4.5 s in the same position (same material). In case of cooling water, the deviation of time period rose to a certain temperature and ranged from 0 to 5.9 s according to the decreasing feed changes of cooling water at 5 %, 10 %, and 15 % compared to a base flow (3.9 kg/s). Finally, the additional researches related to the two different materials (Teflon and STS for Pitch and End-plate), which are concerned about the effects of temperature changes to the parts contacting different materials, are needed, and we have a plan to conduct a follow-up study.

• Korean Journal of Ichthyology
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• v.28 no.4
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• pp.229-238
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• 2016

This study aims to investigate egg quality and amino acid composition of buoyant and non-buoyant eggs and evaluate egg quality of sevenband grouper, Epinephelus septemfasciatus. Amino acid analysis of eggs was conducted to investigate what elements were necessary for the survival and good quality of egg depending on farming condition and different diet. We analyzed amino acid from buoyant eggs and non-buoyant eggs, farming conditions (tank and sea cage), and different dietary conditions (formulated feed, formulated feed+raw fish-based moist pellets, and raw fish-based moist pellets). Egg quality was the best in a sea cage and when raw fish-based moist pellets (MP) were fed. In addition, egg quality with formulated and MP was better than that with formulated feed. As a result of amino acid analysis of eggs, buoyant eggs were containing more free amino acid than non-buoyant eggs. Also, eggs with MP were containing more free amino acid than those with formulated feed and MP. Eggs with mixed formulated feed and MP were containing more free amino acid than formulated feed. In conclusion, amino acid was helpful to improve egg quality, and egg quality can be controlled by farming conditions and feed.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.137-144
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• 2012

This study was conducted to determine the effect of feed additives including probiotics, moisture and feed ingredients and the effect of fermented feed on digestibility and volatile fatty acid (VFA) level in finishing pigs. Feed was mixed with microbials including Saccharomyces, Lactobacillus, Enterococcus and Pediococcus together with different levels of probiotics, 0.25, 0.5, 1, 2, 3%. Addition of probiotics showed improved fermentation rate after 48 h incubation. To determine the optimal moisture level for fermentation, different levels of water, 30, 40, 50 and 60%, were added into the feed. Fermentation rate of feed with 40~50% moisture level was higher than that from 60% level at 60 h post-fermentation. In vitro fermentation rate of feed ingredients was analyzed by comparing VFA levels. Beet pulp and tapioca showed higher fermentation rate compare to other ingredients including canola meal or rapeseed meal. To determine the effect of administration of fermented feed In vivo, feces from finishing pigs were analyzed. Finishing pigs administrated with fermented feed showed improved digestibility and higher volatile fatty acid (VFA) level. In conclusion, results from the current study indicate that 40~50% of moisture with addition of beet pulp and tapioca in feed is optimal condition for fermentation. Furthermore, our data suggest that fermentation of feed can improve the feed quality and digestibility, thereby provide more nutrient in finishing pigs.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.213-216
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• 2002

Food consumption and conversion efficiency of new bivoltine hybrids (CSR2$\times$CSR4 and CSR2$\times$CSR5) were studied under restricted feeding levels (10, 20 and 30% less quantity of mulberry leaves). The data were compared with a control fed with standard quantum of feed as per the recommendation. The nutritional indices parameters i. e. ingests, digesta, approximate digestibility (%) and reference ratio were recorded higher in control batches compared to less feed batches while nutritional efficiency parameters i. e., ECI and ECD to cocoon and shell were recorded significantly higher in restricted feeding level batches. This increase is attributed due to the physiological adaptation under nutritional stress condition.