• Journal of Korean Vacuum Science & Technology
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• v.6 no.3
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• pp.133-138
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• 2002

The growth of Au films grown on a Si(100)-2x1 surface and Si films on a Ge(100)-2x1 substrate is studied using Positron-annihilation induced Auger Electron Spectroscopy(PAES), Electron induced Auger Electron Spectroscopy(EAES), and Low Energy Electron Diffraction(LEED). Previous work has shown that PAES is almost exclusively sensitive to the top-most atomic layer due to the trapping of positrons in an image potential well just outside the surface before annihilation. This surface specificity is exploited to profile the surface atomic concentrations during the growth of Au on Si(100) and Si on Ge(100) and EAES provides concentrations averaged over the top 3-10 atomic layers simultaneously. The difference in the probe-depth makes us possible to use PAES and EAES in a complementary fashion to estimate the surface and near surface concentration profiles. The results show that (i) the intermixing of Au and Si atoms occurs during the room temperature deposition, (ii) the segregated Ge layer is observed onto the Si layers deposited at 300k. In addition, the prior adsorption of hydrogen prevents the segregation of Ge on top of the deposited Si and that the hydrogen adsorption is useful in growing a thermally stable structure.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.346-352
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• 2014

This research was carried out to investigate the effect of supplemental lighting on stable productivity of paprika (Capsicum annuum L.) during low radiation period of winter season. The supplemental lighting sources used in this research were high pressure sodium (HPS) and lighting emitting plasma (LEP). Photosynthetic photon flux density (PPFD) emitted from both lamps decreased as vertical distance from lamp increased. The PPFD of LEP lamps were twice more than that of the HPS lamp per unit distance, but the rate of decreased PPFD of t he LEP per unit distance was higher than that of HPS lamp. And different degrees of PPFD between HPS and LEP lamps by horizontal distance had a smaller degree of difference than by vertical distance at the 100 cm away point. As daily average PPFD measured at the top of the plant under the supplemental lighting during January, the supplemental lighting significantly increased radiation. Radiation of HPS and LEP lighting was 137% and 315% higher than control (without supplemental lighting = sunlight). Air temperature in the top of the plant was not significant different among treatments. HPS and LEP lighting had no effect on increase of flower settings. Leaf length and width with LEP lighting was the longest, photosynthetic was higher than those of other treatments. Supplemental lighting treatments significant increased fruit length and diameter. Especially LEP lighting treatment had a greater effect on fruit length and diameter. In conclusion, LEP lighting treatment during low radiation period greatly affected growth and production of paprika. Further research will be required for the suitable application of LEP lighting in paprika production.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.2
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• pp.85-89
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• 2018

The effects of distribution temperature due to season all changes on quality and storability of baby leaf beet (Beta vulgaris L.) was examined in modified atmosphere (MA) packages. The beet leaf had been harvested at the 10 cm leaf length stage and packaged with an oxygen transmission rate (OTR) film of $1,300cc{\cdot}m^{-2}{\cdot}day^{-1}{\cdot}atm^{-1}$ and then held at 4 different distribution temperatures which were $-2^{\circ}C$, $4^{\circ}C$, $20^{\circ}C$, or $30^{\circ}C$ for 5 hrs and then stored for 18 days at $8^{\circ}C$. The loss of fresh weight of packged baby leaf beet was lowest at the $4^{\circ}C$ treatment, and below 0.6% in all distribution temperature treatments. The atmosphere composition in packages did not show any significant differences among treatments. The oxygen conc. was the highest at 18.0% after the $4^{\circ}C$ treatment, carbon dioxide conc. showed the maximum value of 4% at the $30^{\circ}C$ and $-2^{\circ}C$ treatments, and ethylene conc. was highest at the $10^{\circ}C$ treatment after 10 days in storage. The hardness was the highest at the $4^{\circ}C$ treatment on the final storage day. The $4^{\circ}C$ treatment showed the highest visual quality and the lowest off-odor and aerobic plate count. Therefore, it is necessary to establish a low-temperature distribution system which is controlled under $4^{\circ}C$, because the baby leaf beet's storability and microbial growth are effected even during a short time of 5 hrs during the distribution process.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.3 s.36
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• pp.197-205
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• 2005

Development of the packaging is one of the critical issues for commercialization of the RF-MEMS devices. RF MEMS package should be designed to have small size, hermetic protection, good RF performance and high reliability. In addition, packaging should be conducted at sufficiently low temperature. In this paper, a low temperature hermetic wafer level packaging scheme for the RF-MEMS devices is presented. For hermetic sealing, Au-Sn eutectic bonding technology at the temperature below $300{\times}C$ is used. Au-Sn multilayer metallization with a square loop of $70{\mu}m$ in width is performed. The electrical feed-through is achieved by the vertical through-hole via filled with electroplated Cu. The size of the MEMS Package is $1mm\times1mm\times700{\mu}m$. By applying $O_2$ plasma ashing and fabrication process optimization, we can achieve the void-free structure within the bonding interface as well as via hole. The shear strength and hermeticity of the package satisfy the requirements of MIL-STD-883F. Any organic gases or contamination are not observed inside the package. The total insertion loss for the packaging is 0.075 dB at 2 GHz. Furthermore, the robustness of the package is demonstrated by observing no performance degradation and physical damage of the package after several reliability tests.

• Korean Journal of Materials Research
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• v.22 no.4
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• pp.190-194
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• 2012

The formation of high-quality polycrystalline silicon (poly-Si) on relatively low cost substrate has been an important issue in the development of thin film solar cells. Poly-Si seed layers were fabricated by an inverse aluminum-induced crystallization (I-AIC) process and the properties of the resulting layer were characterized. The I-AIC process has an advantage of being able to continue the epitaxial growth without an Al layer removing process. An amorphous Si precursor layer was deposited on Corning glass substrates by RF magnetron sputtering system with Ar plasma. Then, Al thin film was deposited by thermal evaporation. An $SiO_2$ diffusion barrier layer was formed between Si and Al layers to control the surface orientation of seed layer. The crystallinity of the poly-Si seed layer was analyzed by Raman spectroscopy and x-ray diffraction (XRD). The grain size and orientation of the poly-Si seed layer were determined by electron back scattering diffraction (EBSD) method. The prepared poly-Si seed layer showed high volume fraction of crystalline Si and <100> orientation. The diffusion barrier layer and processing temperature significantly affected the grain size and orientation of the poly Si seed layer. The shorter oxidation time and lower processing temperature led to a better orientation of the poly-Si seed layer. This study presents the formation mechanism of a poly seed layer by inverse aluminum-induced crystallization.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.165-165
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• 2013

Nickel oxide was deposited on mesoporous silica by atomic layer deposition (ALD) consisting of sequential exposures to Ni(cp)2 and $H_2O$. NiO/silica samples were characterized by inductively coupled plasma-mass spectroscopy (ICP-MS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), etc. The flow-type reactor was used to measure activity of NiO/silica catalyst for catalytic combustion of toluene. The activity of NiO/silica catalyst was evaluated in terms of toluene removal efficiency and selectivity to $CO_2$ and compared with those of bare nickel oxide nanoparticles. In order to investigate influence of reaction temperature on combustion aspect, the catalytic combustion experiments were carried out at various temperatures. We show that both bare and supported NiO can be efficient catalysts for total oxidation of toluene at a temperature as low as $250^{\circ}C$.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.3 s.36
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• pp.227-233
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• 2005

Carbon nanotubes (CNT) which were grown, on the alumina substrate with a pair of comb-type Au electrodes, by plasma enhanced chemical vapor deposition have been investigated for $NO_2$ gas sensor. The electrical resistance of CNT film decreased with temperature, indicating a semiconductor type of CNT, and also the resistance of CNT sensor decreased with increasing $NO_2$ concentration. Upon exposure to $NO_2$ gas, the electrical resistance of CNT film sensor rapidly decreased within 3 minutes, and then showed a constant value after $20\~30$ minutes. It is found that the sensitivity of CNT sensor has been improved by air oxidation. The CNT sensor oxidized at $450^{\circ}C$ for 30 minutes showed higher sensitivity value than that without oxidation by $27\%$, even for a low 250 ppb $NO_2$ concentration at operating temperature of $200^{\circ}C$. But it needs a recovery time more than 20 minutes for reuse after detection of $NO_2$ gas.

• Journal of Korean Academy of Nursing
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• v.29 no.3
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• pp.711-720
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• 1999

The purpose of this study was to define the content of physiological knowledge needed for clinical nursing practices. Subjects of physiology were classified into 15 areas, and each areas was further classified into subareas, resulting in a total of 194 subareas. The degree of importance of each subarea was measured with a 4-point scale. The subjects of this study were 179 nurses of two university hospitals located in Seoul and Inchon. The results were as follows : 1. The areas of physiology necessary for clinical nursing practice as a basic knowledge in the order of importance were : blood, respiratory system and renal physiology, function of the immune system, body fluid and cardiovascular system, body temperature, endocrine physiology and gastrointestinal physiology However, the degree of importance for reproductive physiology, neuro-physiology, energy and metabolism, cell and cell membrane physiology, muscular physiology and special sense was relatively low. 2. The most important content of physiology for all clinical areas in nursing was blood physiology. However, the degree of importance for each physiology area was different depending on clinical areas. 3. Subareas of physiology as a basic knowledge for clinical practice and education in nursing were blood transfusion, blood type, function of red blood cell, white blood cell and platelet, characteristics and function of hemoglobin, composition and function of plasma protein, and mechanism of blood coagulation and anticoagulation. In conclusion, areas of physiology necessary for clinical nursing practice were blood, respiratory system and renal physiology, function of immune, body fluid and cardiovascular system, body temperature, endocrine physiology and gastrointestinal physiology. However, the degree of importance for each physiology area was different depending on clinical areas In nursing.

• Journal of the Korean Vacuum Society
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• v.16 no.4
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• pp.298-304
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• 2007

We have studied the effect of $N_2$ flow rate on the structural and optical properties of GaN nanorods grown on (111) Si substrates by radio-frequency plasma-assisted molecular-beam epitaxy. The hexagonal shape nanorods with lateral diameters from 80 to 190 nm with increasing $N_2$ flow rate from 1.1 to 2.0 sccm are obtained. However, the ratio of length (thickness) and compact region increases with increasing $N_2$ flow rate up to 1.7 sccm and then saturate. From the photoluminescence, free exciton transition is clearly observed for GaN nanorods with low $N_2$ flow rate. And the PL peak energies are blue-shifted with decreasing diameter of the GaN nanorods due to size effect. Temperature-dependent photoluminescence spectra for the nanorods with $N_2$ flow rate of 1.7 sccm show an abnormal behavior like "S-shape" with increasing temperature.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.81-83
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• 2000

Tin-doped indium oxide(ITO) thin films were deposited on polyethylene terephthalate(PET) at room temperature by oxygen ion beam assisted evaporator system and the effects of oxygen gas flow rate on the properties of room temperature ITO thin films were investigated. Plasma characteristics of the ion gun such as oxygen ions and atomic oxygen radicals as a function of oxygen flow rate were investigated using optical emission spectroscopy(OES). Faraday cup also used to measure oxygen ion density. The increase of oxygen flow rate to the ion gun generally increase the optical transmittance of the deposited ITO up to 6sccm of $O_2$ and the further increase of oxygen flow rate appears to saturate the optical transmittance. In the case of electrical property, the resistivity showed a minimum at 6 sccm of $O_2$ with the increase of oxygen flow rate. Therefore, the improved ITO properties at 6 sccm of $O_2$ appear to be more related to the incorporation of low energy oxygen radicals to deposited ITO film rather than the irradiation of high energy oxygen ions to the substrate. At an optimal deposition condition, ITO thin films deposited on PET substrates showed the resistivity of $6.6{\times}10^{-4}$ ${\Omega}$ cm and optical transmittance of above 90%.