• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.303-306
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• 2009

High temperature solid oxide fuel cells (SOFCs) offer a clean, pollution-free technology to electrochemically generate electricity at high efficiencies. Solid oxide fuel cells in several different designs have been investigated; these include planar and tubular geometries. The tubular type cell is widely researched due to it have advantages about thermal expansion and sealing issues. Unfortunately, lab scale tubular cell for testing has thermal expansion and sealing problems. The previous Jig for lab scale tubular cell testing has many sealing problems. When we feed fuel gas to jig inlet, ceramic glue sealant has amount of gas expansion pressure, because temperature of feeding gas changes ambient temperature to high temperature ($700{\sim}900^{\circ}C$). Furthermore, when we carry out long time test, something like degradation test, crack of ceramic glue sealant due to weakness of mechanical properties can make stop working the test. Additionally, we reduce setting process for assembling, because micanite is not required drying or debinding process.

• Environmental Engineering Research
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• v.23 no.2
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• pp.159-163
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• 2018

The feasibility of applying coagulation-integrated microfiltration (MF) as a pretreatment for an ultrafiltration (UF) feed in oily wastewater treatment was investigated. The effects of different coagulants on oil removal rates from wastewater were studied. The maximum oil removal rate of 82% was obtained after coagulation with 130 mg/L of polyaluminium chloride (PAC). UF flux reached $95L/(m^2{\cdot}h)$ with coagulation-integrated MF as pretreatment. This value was 2.5 times higher than that flux obtained without pretreatment. The value of UF flux increased as the transmembrane pressure (TMP) and cross-flow velocity (CFV) of the UF module increased. UF flux gradually increased when TMP and CFV exceeded 0.4 MPa and 3 m/s, respectively, because of concentration polarization and membrane fouling stabilization. Chemical oxygen demand reduction and oil removal rate reached 95.2% and 98.5%, respectively, during integrated membrane processing with a PAC concentration of 130 mg/L, TMP of 0.4 MPa, and CFV of 3 m/s for UF. In addition, sequentially cleaning the fouling membrane with NaOH and $HNO_3$ aqueous solutions caused UF flux to recover to 90%. These encouraging results suggested that the hybrid integrated membrane process-based coagulation and MF + UF are effective approaches for oily wastewater treatment.

• Journal of the Korean Institute of Gas
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• v.13 no.1
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• pp.9-13
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• 2009

A cause of noise and vibration which come from a Combustion of gas heater are a combustion roar and Combustion oscillation. A character of a combustion roar is that sound pressure is distribute with broad band frequency. otherwise, The presence of combustion oscillation caused by positive Feed Back in Combustion Chamber break out a noise and vibration. Accordingly, The method that be solved a noise and vibration is to make each natural frequency different frequency. first, in order to solve problem, we control ratio of fuel and air. that is, Keep away resonance. second, in order to changing natural frequency of Combustion Chamber, We changed the shape of Economizer.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.1
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• pp.35-40
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• 2001

The physiological role of brain neuropeptide Y (NPY) in the central regulation of grass intake in sheep was investigated through a continuous intracerebroventricular (ICV) infusion of NPY at a dose of $5{\mu}g/0.2ml/hr$ for 98.5 hours from day 1 to day 5. Sheep (n=5) were fed for 2 hours once a day, and water and 0.5 M NaCl solution were given ad libitum. Feed intake during ICV NPY infusion increased significantly compared to that during ICV artificial cerebrospinal fluid (CSF) infusion. Water and NaCl intake during ICV NPY infusion remained unchanged. Mean arterial blood pressure (MAP) and plasma osmolality during ICV NPY infusion were not significantly different from those during ICV CSF infusion. On the other hand, plasma glucose concentration during ICV NPY infusion increased significantly compared to that during ICV CSF infusion. The results suggest that brain NPY acts as a hunger factor in brain mechanisms controlling feeding to increase grass intake in sheep.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.1
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• pp.89-95
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• 1995

The efficient use as a protein source for poultry of full fat soybean (FFSB) treated under various processes, i. e. steaming under pressure 40 lbs/sq. inch for 5, 10 or 15 minutes or roasting in a baking oven at $180^{\circ}C$ for 20, 30 or 40 minutes or extruding was compared with that of soybean meal. Eight hundred straight run broiler chicks (AA 707) were randomly allotted into 8 treatments of 4 replicates, fed with, rations containing either kind of the above mentioned FFSB for 6 weeks (Wks 1-7). The protein content of the diets for chicks during 1-3, 3-6 and 6-7 weeks of age was 21, 19 and 17% respectively. The result revealed that steaming can destroy 76-92% of the trypsin inhibitor activity (TlA) in soybean, particularly that at 15 minutes, while roasting can get rid of only 13-28% TlA. Chicks fed roasted FFSB had an enlarged pancreas and showed inferior performances to the steaming and the extrusion products. Steaming should be at least 10-15 minutes in order to obtain the comparable performances to those of the extrusion or of the soybean meal. The extruded FFSB showed the best feed conversion ratio. This might be due to the very fine particle of the product.

• Membrane Journal
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• v.10 no.3
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• pp.155-162
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• 2000

The reverse osmosis membrane housing(HY) was developed for excellent distribution of a feed solution, and the separation performance was compared with the commercialized Rochem(RC) system. The permeation flux of HY system was a little lower than that of RC system. On the other hand, the NaCl rejection ra4io was generally higher. Also, the permeation flux and rejection ratio for type A, B and C modules(disc plate and frame type) were measured using NaCl, sucrose and butanol solutions. The separation performance of type C module for NaCL and sucrose solutions was the most effective, and then those of type A and B were followed, respectively. However, the separation performance for butanol solution was type B, C and A order. The flux improvement ratio of type B to A increased as butanol concentration decreased or operating pressure increased up to 28 bar.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.1
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• pp.35-40
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• 2008

Ni-based amorphous alloy ribbon was prepared by a single-roller melt-spinning technique. Palladium coating was found to enhance significantly the absorption/desorption behavior of hydrogen in amorphous alloy. The hydrogen permeability of a Pd-coated $(Ni_{60}Nb_{40}){_{100-X}}$TaX(x=5, 10) amorphous alloy was examined in the temperature range of $623{\sim}773K$, comparable with those of $Pd_{60}-Cu_{40}$ alloys. The permeated hydrogen flux was increased with increasing the temperature and the difference of hydrogen pressure between the feed side and permeates side of the membrane. The Ni-based amorphous alloys were characterized by X-ray diffractometry(XRD) and differential scanning calorimetry(DSC). The morphology of surface and roughness was observed by using scanning electron microscopy(SEM) and atomic force microscopy(AFM).

• Journal of Ocean Engineering and Technology
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• v.13 no.3B
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• pp.38-46
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• 1999

Increasing stringent emissions legislation and requirement of more effective energy used for diesel engine demand the fine control of the fuel injection system. Recently, the electromagnetic fuel injection control system for diesel engine is tried to realize the optimum diesel combustion by the feel back sensing as optical signal of combustion flame. The photo detectors were made for the feed back signal of electromagnetic fuel injection control for small DI diesel engine. Their abilities to detect defining combustion events were examined. By evaluating test results, it was shown that the wider acceptable optical range design of optical probe window face, and selection of installation position and installation method of detector were important point for improving sensing ability. The detector was shown to detect start and end of diffused combustion and maximum point of flame intensity impossible for pressure sensor, and also shown that the maximum point of flame intensity was 75% of accumulated heat release point within the experimental conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.342-350
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• 2009

Fuel cells convert a fuel together with oxygen in a highly efficient electrochemical reaction to electricity and water. Since the electrochemical reaction in the fuel cell stack dose not generate any noise, Fuel cell systems are expected to operated much quieter than combustion engines. However, the tonal noise and the broad band noise caused by a centrifugal compressor and an electric motor cause which is required to feed the ambient air to the cathode of the fuel cell stack with high pressure. In this study, the multi-camber perforated muffler is used to reduce noise. We propose optimized muffler model using an axiomatic design method that optimizes the parameters of perforated muffler while keeping the volume of muffler minimized.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.1 no.1
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• pp.87-94
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• 2001

Silicon nitride films grown by plasma-enhanced chemical vapor deposition (PECVD) are useful for a variety of applications, including anti-reflecting coatings in solar cells, passivation layers, dielectric layers in metal/insulator structures, and diffusion masks. PECVD systems are controlled by many operating variables, including RF power, pressure, gas flow rate, reactant composition, and substrate temperature. The wide variety of processing conditions, as well as the complex nature of particle dynamics within a plasma, makes tailoring SiN film properties very challenging, since it is difficult to determine the exact relationship between desired film properties and controllable deposition conditions. In this study, SiN PECVD modeling using optimized neural networks has been investigated. The deposition of SiN was characterized via a central composite experimental design, and data from this experiment was used to train and optimize feed-forward neural networks using the back-propagation algorithm. From these neural process models, the effect of deposition conditions on film properties has been studied. A recipe synthesis (optimization) procedure was then performed using the optimized neural network models to generate the necessary deposition conditions to obtain several novel film qualities including high charge density and long lifetime. This optimization procedure utilized genetic algorithms, hybrid combinations of genetic algorithm and Powells algorithm, and hybrid combinations of genetic algorithm and simplex algorithm. Recipes predicted by these techniques were verified by experiment, and the performance of each optimization method are compared. It was found that the hybrid combinations of genetic algorithm and simplex algorithm generated recipes produced films of superior quality.