• Journal of Animal Environmental Science
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• v.8 no.3
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• pp.183-190
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• 2002

A study was conducted to determine the effect of dietary probiotics or antibiotics on growth and pathological status in growing-finishing pigs. Ninety male pigs weaned at 24 days of age were divided into three groups of 30 pigs each on the basis of body weight and litter. Three groups of ten pigs(one pen) each were assigned to one of the following diets; a control diet or diets containing 0.1% probiotics or 0.1% antibiotics (1:1 mixture of kitasamycin and sulfamethazine). Average daily gain (ADG), feed efficiency(G/F) and the pathological status were monitored. ADG, feed efficiency and carcass quality were not different (P>0.05) among the three treatments. But pork quality in pigs fed probiotics tended to be improved, compared to other treatments. The pigs fed probiotics had lower pathological lesion in intestinal monitoring than that of other treatments pigs. The chemical composition of slurry(BOD, COD, SS, T-N, T-P and ammonia) in the probiotics treatments tended to be decreased, compared to other treatments. Results of this study suggest that dietary probiotics improve pigs' housing environment, and decrease the contents of polluting materials in slurry.

• Journal of Energy Engineering
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• v.6 no.1
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• pp.96-103
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• 1997

Coal gasification experiments were performed to characterize the bench scaled unit of 0.5∼1.0 T/D entrained coal gasifier developed by KIER. Datong coal from China was selected for this study. The system was operated at the temperature range of 1300∼1550$^{\circ}C$, with 62.5% of coal water mixture on the basis of dry coal. Oxygen and slurry mixture were preheated prior to feeding into burner and the ratio of oxygen/coal was in the range of 0.8∼1.2. In the preparation of coal water mixture, 0.3 wt% of CWM1002 and 0.05 wt% of NaOH wire added to reduce viscosity as well as to enhance theological properties of slurry. The resultant gaseous products consist primarily of hydrogen, carbon monoxide, carbon dioxide, and minor amounts of methane. Formation of H$_2$and CO was increased, while CO$_2$was decreased as the reacting temperature being increased due to the char-CO$_2$reaction. Maximum production of H$_2$and CO occurred in the O$_2$/coal ratio of 0.9 at 1530$^{\circ}C$. Heating values of product gases were in the range of 1700∼2400 kcal/N㎥.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.136-143
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• 2002

Emission of methane and nitrous oxide affected by nitrogen fertilizer materials were measured simultaneously in rice paddy fields under flooding and intermittent irrigation in 2000. Studies focused on mitigating $CH_4$ emission from rice paddy fields are summarized and the possibilities and limits applied to world's rice cultivation are discussed. The mitigation options are water management, soil amendments, organic matter management, different tillage, rotation, and cultivar selection. Altering water management, in particular promoting midseason aeration by short-term drainage, is one of the most promising strategies, although these practices may be limited to the rice paddy fields where the irrigation system is well prepared. The test site was divided into two water managements: a continuously flooded plot which was maintained flooded by constant irrigation from May to September, and an intermittently drained plot in which short-term (20days) draining practices were performed one times during the flooding period. By total emission of GHGs converted by global warming potential (GWP), flooding plots were higher 170$\sim$208% than interimittent irrigation plots. For emission of GHGs in fertilizer materials, it was high in the order of Swine slurry>Urea+Rice straw>Urea>LCU. Basing on GHGs emission of urea fertilization under flooding as baseline GWP of urea fertilization and Latex-coated urea under intermittent irrigation showed lower GHGs emission by 41.4% and 55.8 respectively. In this case fertilizer use efficiency (kg unhulled rice/ of applied N) were 18.2$\sim$20.2 and 18.7$\sim$19.0 and 9.3 and 5.8$\sim$6.6 for Swine slurry and LCU and Urea+Rice straw and Urea in the continuously flooded and intermittently drained plot.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.439-444
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• 2012

We studied the characteristics of odor emitted from 40 swine facilities across the country under various conditions like rearing densities, management style, ventilation system and swine manure handling characteristics, based on the olfactory and analytical evaluation. Odor concentrations (D/T) measured from swine facilities were respectively an average 4,055 D/T at liquid manure storage tanks on aeration, an average 913 D/T at slurry manure storage, an average 506 D/T at finishing swine facilities and an average 201 D/T at composting facilities. The higher rearing densities and slurry accumulation volume in finishing swine house, the more odor concentration (D/T) was increased. But The odor concentration (D/T) in finishing swine house did not show significant difference according to application of microbial additives. 9 odor compounds ($NH_3$, $H_2S$, MM, DMS, DMDS, PA, n-BA, n-VA, i-VA) were detected at swine facilities and the main odor compounds were volatile sulfur compounds such as $H_2S$, MM and volatile fatty acids compounds such as n-BA, n-VA, i-VA. 97.5% of swine farms surveyed in this study is located within 300 m of residential area and it is easy to bring odor complaints.

• The Journal of Engineering Research
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• v.5 no.1
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• pp.73-87
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• 2004

The synthesis and crystallization of amorphous calcium carbonate($CaCO_3$.$nH_2 O$) obtained from gas-liquid reaction between aqueous solution of calcium hydroxide and carbon dioxide at 15~$50^{\circ}C$ are investigated by electrical conductometry, XRD and TEM. The results are as follows: The initial reaction products prior to the formation of precipitated calcium carbonate is amorphous calcium carbonate. The electrical conductivity values in the slurry are decreased during the formation of amorphous calcium carbonate which covers particle surface of calcium hydroxide and retard the dissolution of calcium hydroxide into the solution. that amorphous calcium carbonate is unstable in the aqueous solution and crystallizes finally to calcite by the through-solution reaction. While amorphous calcium carbonate crystallizes into chain-like calcite, the conductivity values are recovered rapidly and the apparent viscosity of slurry containing higher concentration of calcium hydroxide increase. At below pH 9.5, chain-like calcite separates into individual particles to form precipitated calcium carbonate. The formation and synthetic temperature range of amorphous calcium carbonate is most suitable a primary decreasing step(a-step) at $15^{\circ}C$ in the electrical conductometry.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.404-412
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• 2015

The slurry composting and bio-filtration (SCB) liquid manure has some obvious advantages including a good source of N, P and K, local availability, effective microorganism and the ability to improve soil properties. This study was conducted to evaluate the influence on the changes of soil chemical properties and yield of red pepper by fertigation cultivation with SCB application for 2 years. Red pepper was transplanted in early May in 2013 and 2014. The treatment with three replication was composed of 4 types as control (N 1.0), SCB 0.5N, SCB 1.0N, and SCB 2.0N standards of recommended nitrogen fertilizer ($19kg\;N\;10a^{-1}$). The fertigation cultivation which was installed the surface drip irrigation system was splitted 10 times as $2.5Mg\;10a^{-1}$ nutritional solution included with chemical fertilizer and SCB every 10 days during the cultivation. The height and width of pepper plant were 7.0% and 5.8% higher in SCB 2.0N treatment than that in control. The yield of red pepper increased with the increasing of SCB application rates from SCB 0.5N to 2.0N. The yield of SCB 1.0N was much better 10% in average than that of control, and there was significant differences among all treatments. pH of control soil after final harvest decreased to 6.1, however pH of SCB treated soils increased from 6.7 to 7.1 depending on SCB application rates. The Exch.-K contents of SCB treated soils were increased 13.7 to 56.9% after final harvest compared with control by $0.51cmol_c\;kg^{-1}$. Accordingly, these results showed that SCB 1.0N application rate as a recommended nitrogen level based on soil testing can be used as an alternative nitrogen management as well as plant nutrition for red pepper cultivation.

• Membrane Journal
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• v.31 no.6
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• pp.443-455
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• 2021

In this study, polyphenylene sulfide (PPS) was used as a support and a separator was manufactured using polysulfone and inorganic additives to manufacture a separator with low membrane resistance for application of an alkali water electrolysis system, and then the effect on the thickness and porosity of the support was analyzed. The PPS felt used as a support was compressed with variables of temperature (100℃, 150℃, 200℃) and pressure (1 ton, 2 tons, 3 tons, 5 tons) to adjust the thickness. A porous separator could be manufactured by preparing a slurry with polysulfone using BaTiO₃ and ZrO₂ which have high hydrophilicity and excellent alkali resistance as inorganic particles and casting the slurry on a compressed PPS felt. Changes in morphology of the separator according to compression conditions were confirmed through an electron scanning microscope (SEM). After that, the porosity was calculated, and the thickness and porosity tended to decrease as the compression conditions increased. Various characteristics were evaluated to confirm whether it could be used as a separator for water electrolysis. As a result of measuring the mechanical strength, it was confirmed that the tensile strength gradually increased as the compression conditions (temperature and pressure) increased. Finally, it was confirmed that the porous separator manufactured through the alkali resistance test has excellent alkali resistance, and through the IV test, it was confirmed that the membranes compressed at 100℃ and 150℃ had a lower voltage and improved performance than the existing uncompressed membrane.

• Journal of the Korean Ceramic Society
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• v.46 no.1
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• pp.16-23
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• 2009

The porous pellets were prepared from porphyry by slurry foaming method. The effect of sintering temperatures on pore structure of porous porphyry pellets with different extension ratio ($E_R$) was investigated by specific surface area, water absorption and porosity, which changed with sintering temperatures. When the sintering temperatures increased from $975^{\circ}C$ to $1075^{\circ}C$, specific surface area and water absorption of the all samples decreased. In case of the sample with an equal sintering temperature, $E_R=3.0$ pellets had little influence on pore structure compared to the $E_R=2.0$ pellets. As a results, it was shown by SEM that facilitated formation of micro pores at $E_R=2.0$ pellets shrunk increasingly after sintering process. At $E_R=3.0$ and sintering temperature at $1025^{\circ}C$, optimum conditions of the porous porphyry porous pellets was found. Also, Escherichia coli removal efficiency of the silver-containing porphoyry porous pellets was measured for the feasibility as a antibacterial media. The antibacterial activity of prepared silver-containing sample was maintained above 90% for 40 days.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.8
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• pp.863-867
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• 2014

In this study, an acoustic emission (AE) sensor was used for measuring the abrasive and molecular-scale phenomena in chemical mechanical polishing (CMP). An AE sensor is a transducer that converts a mechanical wave into an electrical signal, and is capable of acquiring high-level frequencies from materials. Therefore, an AE sensor was installed in the CMP equipment and the signals were measured simultaneously during the polishing process. In this study, an AE monitoring system was developed for investigating the sensitivity of the AE signal to (a) the variations in the material properties of the pad, slurry, and wafer and (b) the change in conditions during the CMP process. This system was adapted to Oxide and Cu CMP processes. AE signal parameters including AE raw frequency, FFT, and amplitude were analyzed for understanding the abrasive and molecular-level phenomena in the CMP process. Finally, we verified that AE sensors with different bandwidths could function in complementary ways during CMP process monitoring.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.6
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• pp.52-57
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• 1999

Funtional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported by song etc. But a system which can build directly 3D parts of high performance functional material as metal part would need long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we tranlsated the wax patterns to numerous metal prototypes by new investment casting process combined conventional investment casting with rapid pototyping & rapid tooling process. with this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P part to metal part.