• Journal of Korean Society for Atmospheric Environment
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• v.9 no.2
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• pp.140-146
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• 1993

CoMo, NiMo/ZSM-5 catalysts were prepared at Si/Al ratios of 100, 200 and characterized by TGA, XRD and SEM. Simultaneous hydrocracking of n-heptane and hydrodesulfurization of DBT were studied over these catalysts at the ranges of temparatures between 400$^\circ$C and 500$^\circ$C, pressure of 30 $\times 10^5$ Pa and contact time of 0.02g cat. hr/ml feed in a fixed bed flow reactor. It was shown that the hydrocracking activity of n-heptane increased in the order of NM 100, CM 100, NM 200 and CM 200 catalysts. It was also shown that the Hydrodesulfurization activity of DBT increased in the order of CM 200, NM 200, CM 100 and NM 100 catalysts and these results were thought to be that the increase of acidity of catalysts might increase hydrocracking activity of these catalysts but deactive those simultaneously. In this study it was shown that CM 100 and NM 200 were active catalysts in simultaneous hydrodesulfurization of DBT and hydrocracking of n-heptane reactions.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.1
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• pp.73-78
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• 2007

The objective of this work was to simulate lead frame etching characteristics to optimize the etching process, Characteristics such as the etching factor and uniformity were investigated for different actual operating conditions, including pressure, distance from the nozzle tip, pipe pitch, and feed speed. The correlation between the etching and spray characteristics was analyzed to develop the etching model. Spray characteristics obtained from an experiment using a phase Doppler anemometer system were then simulated using a Monte-Carlo technique, The etching process model was coded in the Java language, The spray and etching characteristics were correlated with each other and simulated results agreed well with the measured data for a lead frame etching process, The optimal operating parameters under various conditions were successfully determined.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.243-245
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• 2002

Brackish water desalination using reverse osmosis(RO) membrane is more useful and economic than sea water to solve the shortage of fresh water supply because of its low total dissolved solid(TDS) contents. Silica and humic acid in brackish water make serious fouling problems and cause the decline of permeate flux and increase of operating pressure. In this study, the experiments for removal of silica and humic acid were conducted with calcite particles to prevent membrane fouling and investigated the effect of pH of feed water Adsorption of silica to calcite was higher at pH=7.5 than 9.5 and removal rate was increased according to increase of initial concentration of silica. The effect of pH on adsorption of humic acid was not significant but at low initial concentration the adsorption of humic acid was enhanced at pH 7.5. The result of this study expect to apply to brackish water desalination experiment of flat-sheet reverse osmosis membrane.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.4
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• pp.57-63
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• 2011

The aim of this study is to analyze turning process using commercial FEM simulation code. Various simulation models of orthogonal cutting process for 3 layers of metallic material have been simulated and analyzed. The workpiece material used for the orthogonal plane-strain metal cutting simulation consists of three layers, which are Allow Tool Steel, Aluminum and Stainless Steel. The finite element model is composed of a deformable workpiece and a rigid tool. The tool penetrates through the workpiece at a constant speed and constant feed rate. As an analytical result, detailed cutting temperature, strain, pressure, residual stress for both a tool and each layer of workpiece were obtained during the turning process. It has been closely observed that the chip flow curve deforms continuously.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.7
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• pp.736-745
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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 Industrial Entomology and Biomaterials
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• v.17 no.1
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• pp.109-113
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• 2008

Realizing the scope of utilizing by-products of silk cocoons by applying appropriate methods is the immediate crave to optimize returns. The nutritive value of pupae suits for human diet, feed for poultry, carps, fish, rabbits, piggery and dogs. The pupal skin, fat, oil, cocoon palade have applications in oleo chemical, soap, glycerin, cosmetic, artificial fibres, membranes and n-triacontanol isolation. The pupal proteins Chitin, Shinki fibroin, Serrapeptidase, glucosamine are latent precursors of post surgical, anti-carcinogenic, anti-inflammative, anti-bacterial, anti-histaminic, gastric, hepatitis, pancreatitis, leukocytopenia, neurological, ophthalmic, blood pressure, cardiac and diabetic medicines and for preparation of vitamins A, E and K. The silk and its proteins sericin and fibroin are potentially used for wound healing, diabetes, impotence, sinusitis, arthritis, edema, cystitis, epididymitis, tissue regeneration, cancer, post-surgical trauma and used as anti-oxidatives, bio-adhesives, ultra violet screens and bio-active textiles. The waste cocoons can be used in making art crafts like garlands, carpets, overcoats, decoratives and greeting cards. The in-depth research towards utility optimization and make aware this reality to sericulturists, reelers, weavers, traders, entrepreneurs, policy makers etc., is the upright want of the today's Sericulture industry.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.384-387
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• 2006

수소 스테이션에서 사용할 수 있는 Compact 형 수소 PSA를 연구하였다. 기존의 수소 PSA 가 수소 스테이션에서 공간적 제약이 있기 때문에 그 부피를 줄이면서, 또한 효율을 높이기 위해 Compact형 수소 PSA를 고안하였다. Compact형 수소 PSA는 하나의 bed안에 다른 하나의 bed를 넣음으로써 시스템이 차지하는 부피를 줄이는 한 건, inner bed와 outer bed 사이의 열교환 효과가 나타나기 때문에 그 효율을 높일 수 가 있다. 흡착탑의 동특성을 파악하기 위하여 4성분 (H2/CO2/CH4/CO, 69:26:3:2 vol. %)의 가스를 Feed rate 7LPM, Adsorption Pressure 9atm의 조건으로 실험을 하였다. Inner bed와 outer bed의 흡착 동특성의 차이를 알아보고, PSA 공정을 가상으로 하여 각각의 탑에서 흡착과 탈착이 동시에 일어날 때의 동특성도 알아보았다. 그리고 AD step time을 달리 하면서 PSA 공정에 알맞은 Sequence을 알아보았다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.490-493
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• 2006

The results of simulation of direct methane fuel cell fed with liquid-state methanol feed are shown. This numerical process is based on mass and current conservation equations. The results showed that over low current density $(<200mA/cm^2)$ IV polarization curve was well-presented compared to experimental result. Methanol fed from anodic side moved into cathodic side through electrolyte membrane and the pressure near cathode electrode increased according to amount of methanol crossover and production of water. Besides change of overpotential on each el electrode were checked by x-axis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.224-228
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• 2005

Dynamic control tests for Backhole as a dynamic damper were performed. For the forced oscillation generated by pressure drop in the feed line and internal wave analysis of swirl injector, hydrodynamic pulsator and 1D visualization model injector was produced, respectively We focus on effect of Backhole as a dynamic damper instead of a acoustic one. So, the breakup length and film thickness of liquid sheet on the steady state and the forced oscillation state have been measured and compared.

• Journal of Welding and Joining
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• v.33 no.6
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• pp.42-48
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• 2015

Reduced activation ferritic/martensitic steels are recognized as the primary candidate structural materials for fusion blanket systems. Welding is an inevitable for breeding blanket for pressure tightness and radioisotope confinement. Especially, TIG welding was chosen for sealing because it has the largest gap allowance compared to the other welding methods, and its properties are controllable by feed wire and welding conditions. In this study, the low cycle fatigue test using two-type gage such as extensometer and strain gage was applied to the TIG welded joint of F82H steel, for evaluating fatigue damage accumulation behavior of the HAZs. As the result, the over-tempered HAZ have shown a higher fatigue damage accumulation compared with other materials at all the testing conditions.