Kim T.-Y.,Hanyang University |
Hwang J.-Y.,KITECH |
Moon S.-J.,Hanyang University
Japanese Journal of Applied Physics | Year: 2010
The spectral optical properties of the silver/copper nanoparticle ink at visible and near-infrared wavelength were measured by ellipsometry. The purpose of the measurement of the optical properties is to select the optimal process parameters such as working wavelength and laser incidence angle by finding the maximum absorption wavelength. The reflectance and absorptivity of the nano-ink including silver/copper nanoparticles were calculated from the experimentally obtained refractive indices. The absorptivity has been maximized at the green wavelength for the normal incident angle to the target at the initial stage of the curing. Therefore, a continuous wave green laser at the wavelength of 532nm is chosen for the laser curing. For the laser curing process, the inkjet-printed silver/copper nano-ink samples on the glass and poly(ethylene terephthalate) (PET) substrates are adopted to find the effect of the substrate materials on laser curing process. The used laser energy is 31.62 and 177.27W/ cm2 to analyze the effect of the laser intensity on laser curing process. The nano-ink on the PET substrate has lower specific resistance than that on the glass substrate with the identical laser irradiation time. The higher laser intensity is recommended to obtain the lower specific resistance with same laser irradiation. Compared with the 30-min furnace curing process at the temperature of 250 °C, a few seconds laser curing process can be effectively adopted with appropriate scanning system to shorten the curing time. © 2010 The Japan Society of Applied Physics.
Nersisyan H.H.,Chungnam National University |
Journal of Materials Processing Technology | Year: 2013
In this study, intermetallic compound formation at the interface between aluminum and copper during hydrostatic extrusion was simulated by performing a solid state diffusion bonding experiment with various processing parameters, including bonding temperature and pressure and holding time, and by inserting an Ag colloid layer between the aluminum and copper. Regression equations were developed to predict thickness of diffusion layer and interface hardness. An intermetallic compound formed at the interface between the Al and Cu during diffusion bonding at 420°C and 240 MPa for 60 min, and it was effectively controlled by inserting an Ag colloid. These experimental data will be useful for setting up processing parameters to prepare Al/Cu matrix composite materials by using hydrostatic extrusion. © 2012 Elsevier B.V.
Chang H.N.,KAIST |
Jung K.,KAIST |
Choi J.-D.-R.,KAIST |
Choi J.-D.-R.,GS Caltex Corporation |
And 2 more authors.
Biotechnology Advances | Year: 2014
A multi-stage continuous high cell density culture (MSC-HCDC) system makes it possible to achieve high productivity together with high product titer of many bioproducts. For long-term continuous operation of MSC-HCDC systems, the cell retention time and hydraulic retention time must be decoupled and strains (bacteria, yeast, plant, and animal cells) must be stable. MSC-HCDC systems are suitable for low-value high-volume extracellular products such as fuel ethanol, lactic acid or volatile fatty acids, and high-value products such as monoclonal antibodies as well as intracellular products such as polyhydroxybutyric acid (PHB), microbial lipids or a number of therapeutics. Better understanding of the fermentation kinetics of a specific product and reliable high-density culture methods for the product-generating microorganisms will facilitate timely industrialization of MSC-HCDC systems for products that are currently obtained in fed-batch bioreactors. © 2014.
Applied Mechanics and Materials | Year: 2013
In this paper, a change of die roll height according to the die chamfer shape and V-ring distance of a fine blanking tool was studied by experiments on a special part with various corner shapes. Three guide plate inserts with different V-ring positions and three die inserts with different die chamfers were machined, and then a fine blanking tool was manufactured for the fine blanking experiments. Nine experiments were conducted on a 650-ton fine blanking press. Each die roll height was measured and analyzed. It would be noticed that the die roll heights on the corner shapes of the fine blanked parts increased with increasing V-ring distance and die chamfer angle, but it decreased with increasing corner radius and angle. The results in this study can be used to minimize the die roll height of fine blanked parts with corner shapes when designing the V-ring and die chamfer of a fine blanking tool. © (2013) Trans Tech Publications, Switzerland.
Communications in Computer and Information Science | Year: 2012
We, KITECH, had developed CAE software for casting industries(foundries) over last 10 years, and distributed the developed CAE package for foundries in south korea. But the gorwth rate of market for CAE technologies becomes slower because of expensive prices of CAE tools and lacks of trials for introducton of new technologies into their manufacturing workplaces. So that we have been developing new concept market for CAE tehcnologies for last 5 years, and built cloud platform services for CAE in south korea, and it is ISC(Internet Simulation Center). We setup cluster computing systems, datacenter for infrastructure, and developed various services and relational interfaces to serve cloud computing services. So that we have loaded 4 CAE contents into our cloud computing platform, and are providing CAE services to domestic users. © 2012 Springer-Verlag.