• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.391-394
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• 2003

Laser direct writing process is developed 3rd harmonic Diode Pumped Solid State Laser with the near visible wavelength of 355 m sensitive polymer is irradiated by UV laser and developed using polymer solvent to obtain quasi-3D. It is important to reduce line width for image mode waveguides, so some investigations will be carried out in various conditions of process parameters such as laser power, writing speed, laser focus and optical properties of polymer. This process could be to fabricate a single mode waveguide without expensive mask projection method. Experimentally, the patterns of trapezoidal shape were manufactured into dimension of 8.4 mm width and 7.5 mm height. Propagation loss of straight waveguide measured 3 dB/cm at 1,550 nm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.612-615
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• 2003

Maskless laser patterning process is developed using 3rd harmonic Diode Pumped Solid State Laser with near visible wavelength of 355 nm. Photo-sensitive curable polymer is irradiated by UV laser and developed using polymer solvent to obtain quasi-3D patterns. We performed basic experiments for the various process conditions such as laser power, writing speed, laser focus, and polymer optical property to gain the optimal conditions. Experimentally, the patterns of trapezoidal shape were manufactured into dimension of 8${\mu}{\textrm}{m}$ width and 5.4${\mu}{\textrm}{m}$ height. This process could be applied to fabricate a single mode waveguide without expensive mask projection method.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2160-2163
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• 2005

Solid freeform fabrication (SFF) technology plays a major role in industry and represents a reasonable percentage of industrial rapid prototyping/tooling/manufacturing (RP/RT/RM) development applications. However, SFF technology still has long way to progress to achieve satisfactory process speed, surface finish and overall quality improvement of its application. Today, three dimensional printing (3DP) technique that is one of SFF technology is receiving many interests, and is applied by various fields. It can fabricate three dimensional objects of solid freeform with high speed and low cost using ink jet printing technology. However, need long curing time after manufacture completion. And it must do post-processing process necessarily to heighten strength of objects because strength of fabricated objects is very weak. Therefore, in this study, we proposed an improved 3DP process that can solve problems of conventional 3DP process. The general 3DP process is method to spout binder simply through printer head on powder, but proposed process is method to cure jetted UV resin by UV lamp after jet UV resin using printhead on powder. The hardening of resin is achieved strongly at early time by UV lamp in proposed method. So, the proposed process can fabricate three dimensional objects with high speed without any post-processing.

• Korea-Australia Rheology Journal
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• v.20 no.2
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• pp.59-63
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• 2008

A theoretical model was developed to describe the flow behavior of a filled polymer in the packing stage of reaction injection molding and predict the residual stress distribution of thin injection-molded parts. The model predictions were compared with experiments performed for phenol-formaldehyde resin filled with wood dust and cured by urotropine. The packing stage of reaction injection molding process presents a typical example of complex non-isothermal flow combined with chemical reaction. It is shown that the time evolution of pressure distribution along the mold cavity that determines the residual stress in the final product can be described by a single 1D partial differential equation (PDE) if the rheological behavior of reacting liquid is simplistically described by the power-law approach with some approximations made for describing cure reaction and non-isothermality. In the formulation, the dimensionless time variable is defined in such a way that it includes all necessary information on the cure reaction history. Employing the routine separation of variables made possible to obtain the analytical solution for the nonlinear PDE under specific initial condition. It is shown that direct numerical solution of the PDE exactly coincides with the analytical solution. With the use of the power-law approximation that describes highly shear thinning behavior, the theoretical calculations significantly deviate from the experimental data. Bearing in mind that in the packing stage the flow is extremely slow, we employed in our theory the Newtonian law for flow of reacting liquid and described well enough the experimental data on evolution of pressure.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.243-257
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• 2002

A study on processing for producing cure seat radiated by Original Infrared Rays and Magnatic force. We are well aware that Original Infrared Rays and Magnatic force influence on our human body benificially. In the technical background of this research product, we treated that the product has some operations of ceramic hardwood charcoal, far infrared rays and magnetic, so it can serve large part curative values made of far infrared rays and magnetic force of ceramics. Also, in the special quality of the product deal with ceramic, hard charcoal, ferrite, gelatin what is needed in production. And among them, ferrite, ceramic and hard charcoal are introduced by the manufacturing process of the moleculeization. In concluding, this study described the manufacturing process on the basis of the worksheets and arranged the useful effect which effect on human body. There are so many symptoms in the pain of muscle. It's very various. for example, it is the cause of the liver, the spleen and a kidney function's weakening. the cause of the backbone subluxation, the cause of the shoulder joint and scapula, the cause of the sacrum and iliacjoint, the cause of hip joint and the cause of a sprain. In this thesis, we mainly deal with the method which the muscle and nervous system disease by fatigue and a sprain cure seat radiated by Original Infrared Rays and Magnatic force. then, Original Infrared Rays and Magnatic force pack up frapezius muscle, gluteus minimum muscle, gluteus medius muscle, gluteus maximus muscle, pririformis muscle around the spine. through this course the moral pressure by the nervous system disease can be treat.

• Polymer(Korea)
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• v.25 no.1
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• pp.15-24
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• 2001

In this study, the effects of different glycol molar ratios of unsaturated polyester(UPE) resins on the curing behaviors were investigated. The cross linking process was checked or monitored by differential scanning calorimetry(DSC) and by viscoelastic properties of rigid-body pendulum model. The knife-edge from which the pendulum is suspended, is immersed in a reaction mixture, and the change of the viscoelastic behavior brings on those of the period(T) and logarithmic decrement(${\Delta}$) of the damped free oscillations of the pendulum. The values of T and ${\Delta}$ obtained are related to the dynamic modulus(E') and modulus loss(E'). The information on the viscoelastic behavior of unsaturated polyester(UPE) resins during the curing process are shown to illustrate the usefulness of the techniques. As the content of NPG in a propylene glycol(PG)/NPG glycol mixture increased, both the cycle time during cure and the change of damping during cure of UPE resin decreased.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.68
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• pp.9-20
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• 2001

A study on processing for producing cure seat radiated by Original Infrared Rays and Magnatic force. We are well aware that Original Infrared Rays and Magnatic force influence on our human body benificially. In the technical background of this research product, we treated that the product has some operations of ceramic hardwood charcoal, far infrared rays and magnetic, so it can serve large part curative values made of far infrared rays and magnetic force of ceramics. Also, in the special quality of the product deal with ceramic, hard charcoal, ferrite, gelatin what is needed in prodution. And among them, ferrite, ceramic and hard charcoal are introduced by the manufacturing process of the moleculeization. In concluding, this study described the manufacturing process on the basis of the worksheets and arranged theuseful effect which effect on human body. There are so many symptoms in the pain of muscle. It＇s very various. for example, it is the cause of the liver, the spleen and a kidney function＇s weakening. the cause of the backbone subluxation, the cause of the shoulderjoint and scapula, the cause of the sacrum andiliacjoint, the cause of hip joint and the cause of a sprain. In this thesis, we mainly deal with the method which the muscle and nervous system disease by fatigue and a sprain cure seat radiated by Original Infrared Rays and Magnatic force. then, Original Infrared Rays and Magnatic force pack up frapezius muscle, gluteus minimum muscle, gluteus medius muscle, gluteus maximus muscle, pririformis muscle around the spine. through this course the moral pressure by the nervous system disease can be treat.

• Journal of Adhesion and Interface
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• v.9 no.3
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• pp.20-26
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• 2008

It is well know that the structure of shape memory alloy (SMA) can change from martensite austenite by either temperature or stress. Due to their inherent shape recovery properties, SMA fiber can be used such as for stress or cure-monitoring sensor or actuator, during applied stress or temperature. Incomplete superelasticity was observed as the stress hysteresis at stress-strain curve under cyclic loading test and temperature change. Superelasticity behavior was observed for the single-SMA fiber/epoxy composites under cyclic mechanical loading at stress-strain curve. SMA fiber or epoxy embedded SMA fiber composite exhibited the decreased interfacial properties due to the cyclic loading and thus reduced shape memory performance. Rigid epoxy and the changed interfacial adhesion between SMA fiber and epoxy by the surface treatment on SMA fiber exhibited similar incomplete superelastic trend. Epoxy embedded single SMA fiber exhibited the incomplete recovery during cure process by remaining residual heat and thus occurring residual stress in single SMA fiber/epoxy composite.

• Laser Solutions
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• v.8 no.3
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• pp.21-26
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• 2005

A bonding process between tape-carrier package and a glass panel with anisotropic conductive film (ACF) has been investigated by making use of high power diode laser as a heat source for cure. The results from modeling of process and from optical properties of layers showed that heat absorbed from polyimide film surface and ACF layer is dominant source of curing during laser illumination. Laser ACF bonding has better bonding quality than conventional bonding in view of peel strength, flatness, pressure unbalance and processing time. New ACF bonding processes by making use of high power diode laser are proposed.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.159-162
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• 2004

The processing of phenolic composite reinforced with hybrid of PAN based/Rayon based carbon fabrics using FBG sensor and thermocouple was studied. Once the composite is cured, the reflection spectrum from the FBG sensor shifted the center wavelength with an increase in the temperature. Also, the change in the form of the reflection spectrum obtained during the cooling process of the cure cycle was caused by the thermal shrinkage. During the curing process, uniform distribution of the temperature profile was observed throughout the sample.