• Journal of Electrical Engineering and Technology
• /
• v.6 no.2
• /
• pp.275-279
• /
• 2011

Sterilization of Escherichia coli (E. coli) is examined using a unique pulsed ultra-violet (UV) elliptical reactor based on Nd:YAG laser resonator, UV radiation from a pulsed xenon flashlamp. The light from the discharge has a broadband emission spectrum extending from the UV to the infrared region with a rich UV contained. Sterilization method by using the UV light is fast, environment-friendly and it does not cause secondary pollution. A Nd:YAG laser resonator having elliptical shape has advantage of concentrating the radiation of the UV light at two foci as the quart sleeve filled with E. coli. The primary objective of this research is to determine the important parameters such as pulse per second (pps), the applied voltage for sterilizing E. coli by using an UV elliptical reactor. From the experiment result, the sterilization effect of UV elliptical reactor is better than that of UV cylindrical reactor, and it can be 99.9% of sterilization at 800V regardless of the pps within 10 minutes.

• Journal of the Korean Society for Precision Engineering
• /
• v.24 no.2 s.191
• /
• pp.134-139
• /
• 2007

Usually nanosecond pulsed laser processing of metal is mainly affected by the thermal ablation. Many studies of the theoretical analysis and modeling to predict the laser ablation of metal are suggested on the basis of the photothermal mechanism at higher laser fluence. In this paper, we investigate the etching depth and laser fluence of laser ablation of copper foils and propose the simplified SSB Model(Srinivasan-Smrtic-Babu model) to study the photothermal effect of nanosecond pulsed laser ablation. The experimental results show that the photothermal ablation of the 355nm DPSS $NdYVO_{4}$ laser is useful to process the copper thin foils.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.299-300
• /
• 2010

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.49 no.2
• /
• pp.103-106
• /
• 2000

ZnO is a wide-bandgap II-IV semiconductor and has a variety of potnetial applications. ZnO exhibits good piezoelectric, photoelectric and optical properties, and is a good candidate for an electroluminescence device. ZnO films have been deposited on (001) sapphire by PLD technique. Nd:YAG pulsed laser was operated at a wavelength of $\lambda=355nm$. The ZnO films were deposited at oxygen pressures from base to 500 mTorr. The substrate temperatures was increased from $200^{\circ}C\; to\;700^{\circ}C$ films showed strong UV emission by increasing the partial oxygen pressure. We have investigated the relationship between partial oxygen pressure and the intensity of UV emission.

• Proceedings of the KIEE Conference
• /
• 1999.11d
• /
• pp.888-890
• /
• 1999

ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition using a Nd:YAG laser with the wavelength of 355 nm at an oxygen pressure of 350 mTorr. In order to investigate the effect of the substrate temperature on the properties of ZnO thin films, the experiment has been performed at various substrate temperatures in the range of $200^{\circ}C$ to $700^{\circ}C$. According to XRD, (002) textured ZnO films of high crystalline quality have been obtained by pulsed laser deposition technique. However, the intensity of UV emission is mostly depending on the stoichiometry of ZnO films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.95-98
• /
• 1999

ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition technique using a Nd:YAG laser with the wavelength of 355 nm. In order to investigate the effect of the deposition conditions on the properties of ZnO thin films at an oxygen pressure of 350 mTorr, the experiment has been Performed at various substrate temperatures in the range of 20$0^{\circ}C$ to $700^{\circ}C$. According to XRD, (002) textured ZnO films of high crystalline quality have been obtained and the intensity of UV emission was the highest at 40$0^{\circ}C$ substrate temperature.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.10
• /
• pp.29-33
• /
• 2010

UV laser micromachining of metallic materials has been used in microelectronic and other industries. This paper shows on experimental investigation of micromachining of copper using a 355nm UV laser with 50ns pulse duration. A finite element model with high strain rate effect is especially suggested to investigate the phenomena which are only dominated by mechanically pressure impact in disregard of thermally heat transfer. In order to consider the strain rate effect, Cowper-Symonds model was used. To analyze the dynamic deformation during a very short processing time, which is nearly about several tens nanoseconds, a commercial Finite Element Analysis (FEA) code, LS-DYNA 3D, was employed for the computational simulation of the UV laser micro machining behavior for thin copper material. From these computational results, depth of the dent (from one to six pulsed) were observed and compared with previous experimental results. This will help us to understand interaction between UV laser beam and material.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.5
• /
• pp.2979-2984
• /
• 2015

This paper has presented a new foaming technology of selective hybrid-structured polymer film with expanded pores. The porous structure of closed pore was firstly fabricated by applying the 355nm UV-pulsed laser to 0.1mm thick film that was uniformly mixed with PP pellets, copper powder, and CBA (Chemical Blowing Agent). In order to expand pore size of closed-cell shape, LAMO(Laser Aided Micro pore Opening) processing was conducted to heat the copper powder, and then the bigger pore size of closed-cell more than existing pore size was successfully formed because of rapid conduction of heated metal powder. From the experimental results, various process parameters such as laser fluence, intensity, scan rate, spot size and density of powder and CBA were considerably considered to reveal the correlation among the pore characteristics. In the future, a function experiment will be carried out to use the hybrid film of industrial applications.

• Journal of the Microelectronics and Packaging Society
• /
• v.28 no.4
• /
• pp.51-55
• /
• 2021

The nurses manually carry out the intravenous therapy for the patients. Using an Arduino, the fine flow controlling device was invented to provide an ongoing patient care. The medication is injected through a peristaltic pump, and the amount of the solution is controlled with a RGB color sensor. The power of the device is supplied through the batteries. An amount of the injection is measured with LIG strain sensor fabricated by 355nm UV pulsed laser. This system will provide a better medical service.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.14 no.3
• /
• pp.246-250
• /
• 2001

ZnO thin films for light emission device have been deposited on sapphire and silicon substrates by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of355 nm. In order to investigate the emission properties of ZnO thin films, Pl measurements with an Ar ion laser a light source using an excitation wavelength of 351 nm and a power of 100 mW are used. All spectra were taken at room temperature by using a grating spectrometer and a photomultiplier detector. ZnO exhibited Pl bands centers around 390, 510 and 640 nm, labeled near ultra-violet(UV), green and orange bands. Structural properties of ZnO thin films are analyzed with X-ray diffraction(XRD).