• Journal of Korea Multimedia Society
• /
• v.14 no.3
• /
• pp.414-422
• /
• 2011

The paper is for top and bottom symmetrical phase controlled loop antenna using for multi-media devices. We developed a top and bottom phase control loop pattern arrangement methods for loop antenna in mobile devices like as a cell phone and PCS, WCDMA. In the loop antenna pattern, arrange close adhesive the loop antenna pattern $180^{\circ}$ cycle in wave length, the radiated electro-magnetic wave from close adhesive loop pattern in $180^{\circ}$ become to coherent wave than the phase controlled loop antenna has high efficiency and high radiation gain. To acquire a wide band width on phase controlled loop antenna, we arrange a top and bottom symmetrical architecture loop pattern that bas a $180^{\circ}$ wave length in each layer. Top and bottom each layer bas a U form pattern separated $90^{\circ}$ wave length each other. This architecture cause a well balanced electro-magnetic flow control that acquired wide bandwidth resonance response in loop pattern antenna. In experiment, we designed a WCDMA mobile multi-media antenna in $40mm{\times}6mm$ area thickness 0.2mm, in that passive experiment the radiation efficiency is over 50% and over 0dBi radiation average gain was acquired, in the active experiment in real multi-media device we acquired -4dBi average gain and 43% transmit/receive efficiency.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2003.04a
• /
• pp.135-136
• /
• 2003

알코올 분무, 셀로판지 부착 등의 표면처리가 포장김치의 표면갈변과, pH, 산도, 균수 및 관능적 품질에 미치는 영향을 조사하였다. 실험에 사용된 포장김치는 200 g 들이 플라스틱 용기에 김치를 담은 후 무처리, 70% 알코올로 표면을 1회 분무한 것, 김치표면에 폴리에틸렌필름(두께 0.04 mm)을 부착하여 저장실 (10$\pm$1$^{\circ}C$)에서 21일간 저장하면서 3일 간격으로 조사하였다. 그 결과, 무처리와 알코올을 분무한 경우는 저장 15일째에 pH가 4.0수준에 도달하였으나 김치표면에 polyethylene film을 부착한 경우는 21일째까지도 pH가 4.0 이상을 유지하였다. 산도의 경우도 pH와 동일한 경향을 나타내어 polyethylene film으로 표면처리함으로서 김치의 숙성이 지연되었다. 무처리와 알코올을 처리한 것은 12일째부터 김치표면이 갈변하기 시작하였으며 18일째는 그 갈변정도가 심하였다. 그러나 polyethylene film을 표면에 부착한 경우는 저장 21일째까지도 갈변정토가 미약하였다. 저장기간에 따른 총균수의 변화는 무처리와 알코올을 처리한 경우가 polyethylene film을 부착한 경우에 비하여 증가폭이 컸으나 젖산균수는 반대로 polyethylene film을 부착한 경우가 무처리 또는 알코올을 분무한 경우에 비하여 높아 김치의 품질이 양호하였다. 무처리와 알코올을 분무한 김치의 표면에는 저장 15일 이후에 산막표모 및 곰팡이의 균사체가 번식하는 김치도 발견되었다. 처리별 이미 및 이취의 발생정도를 조사한 결과 무처리와 알코올을 처리한 경우는 저장 15일경에 특히 용기 표면에 위치하는 김치에서 이미와 이취가 있었으나 polyethylene film을 부착한 경우는 이미와 이취가 전혀 나타나지 않았다.채반에 넣고 밀도를 측정한 결과 1.002g/㎤을 나타냈다. 즉 물의 이론밀도인 1g/㎤에 근접한 값을 보여 정확한 밀도 계측이 가능한 것으로 판단되었다. 또한 밀도 계측시스템의 측정 반복간 정밀도를 파악하기 위해 수박 6개를 임으로 선정하여 3반복 측정 시험한 결과, 측정표준편차가 0.001~0.004g/㎤로 해상도보다는 다소 높았으나 대체로 양호한 결과를 나타냈다. 수박 35개를 이용하여 개발 계측시스템과 사람이 직접 부력법으로 밀도를 측정 비교한 결과, 계측시스템에 의해 측정된 수박 밀도가 사람이 측정했을 때 보다 낮게 측정되었다. 수박의 외관인자(무게, 길이, 직경, 체적), 밀도와 당도의 상관관계 구명시험을 위해 원예연구소 시험포장에서 재배된 삼복꿀수박 총 74개를 공시재료로 하였고, 시험은 출수일별로 10~14개씩 수확하여 외관인자, 밀도, 당도를 각각 측정하고, 이들 인자들간의 상관관계를 구명하였다. 외관인자들간에는 높은 상관관계를 보였으나, 외관인자들과 밀도, 외관인자들과 당도, 밀도와 당도와는 매우 낮은 상관관계를 나타냈다. 점성에 영향을 미치는 가장 주요한 조건이라고 생각된다.환원당인 sucrose 함량은 계속 증가하였고 fructose, glucose, sorbitol의 함량(추황의 sorbitol을 제외)은 생장이 촉진됨에 따라 증가하다가 다시 점차적으로 감소하였다. 이러한 결과는 총당과 환원당의 측정결과와 일치한 것으로 나타났다. 결론적으로 배의 성장에 따라 산 함량은 감소하였고 당 함량은 증가하였다.luco-pyranoside, quercetin 7-O- -glucopyranoside, acacetin 7-O-$\beta$-D-glucuronide and apigenin-6-C-$\beta$-D-glucopyranosyl-8-C-$\b

• Progress in Medical Physics
• /
• v.7 no.2
• /
• pp.19-28
• /
• 1996

It is important that the precise decision of the region and the accurate delivery of radiation dose required for treatment in the stereotactic radiosurgery. In this research, radiosurgery was carried with Leksell streotactic frame(LSF) which is especially developed water phantom to verify in experiment. Leksell Gamma Knife and LSF are used in radiosurgery is the spherical water phantom has the thickness of 2 mm, the radius of 160mm. The film for target localization and ionchamber for dose delivery was used in measurement instruments We compare the coordinate of target which is initialized by biplannar film with simple X-ray to the coordinate of film measured directly. The calculated dose by computer simulation and the measured dose by ionization chamber are compared. In this research, the target localization has the range ${\pm}$0.3mm for the acceptable error range and the absolute dose is :${\pm}$0.3mm for the acceptable error range. This research shows that the values measured by using the especially manufactured phantom are included the acceptable error range. Thus, this water phantom will be used continuously in the periodic quality assurance of Gamma Knife Unit and Leksell Stereotactic Frame.

• Korean Journal of Food Science and Technology
• /
• v.24 no.6
• /
• pp.574-580
• /
• 1992

Chitin was isolated from the residue of enzymatically hydrolyzed crab, Portunus trituberculatus, and further deacetylated by alkaline boiling to make chitosan. The physical properties of chitosan solution and its film forming properties were examined. The functional characteristics of chitosan film were compared to those of cellophane, polyvinyl chloride (PVC) and polyethylene (PE) films. The proximate chemical composition of chitin obtained from crab residue was 6.95% nitrogen, 0.3% crude ash and 4.57% moisture and the product yield was 12.8% based on a dry material basis. The degree of deacetylation of chitosan was $79{\sim}92%$ and $70{\sim}86%$ as determined by IR spectroscopy, and $70{\sim}86%$ as determined by colloid titration method each respectively. The chitosan at 1% acetic acid solution showed distinct pseudoplastic flow behavior. The flow behavior index and consistency index were 0.8886, 0.2084 $MPa{\cdot}s^n$ for 0.4% solution and 0.8498, 0.6190 $MPa{\cdot}s^n$ for 0.8% solution, respectively. The chitosan film had the highest tensile strength $(888 kg/cm^2)$ and water permeability $(100\;g/m^2{\cdot}24\;hrs)$ among the tested films, but relatively low elongation property (49%). It showed the similar tear strength (90kg/cm) and light permeability (87.7%) to other films tested in spite of the relatively high haze value (12.5%). As the thickness of chitosan film increased from 0.025 to 0.050 mm, the tensile strength of film decreased distictively, and the degree of elongation, tear strength, and water permeability of film also decreased slightly. Whereas the light permeability of film did not change and the haziness of film slightly increased by the increase of film thickness.

• Korean Journal of Optics and Photonics
• /
• v.21 no.1
• /
• pp.33-37
• /
• 2010

We performed time-domain terahertz (THz) spectroscopy to determine optical constants of highly conductive carbon nanotube (CNT) films. The CNT films have been fabricated on a flexible plastic substrate by using spin-coating or vacuum filtration. We found that the transmission of THz waves can be controlled by manipulating the thickness of the films and by post-treatments. From amplitude and phase information of the transmitted THz waves, we obtain optical constants such as refractive indices and dielectric constants of the CNT films. The frequency dependent dielectric constants show good metallic behaviors, relevant to the Drude free electron models with high plasma frequencies. It is also found that the dielectric constants are higher for the acid-treated films. Finally, the frequency dependent dielectric constants which are free from substrate effects have been demonstrated by using CNT films deposited on cellulose membranes.

• Journal of Mushroom
• /
• v.18 no.1
• /
• pp.115-119
• /
• 2020

This study was conducted to investigate the effect of post-harvest CO₂ treatment on the quality of the 'Gonji-7ho' oyster mushroom. The harvested mushrooms were pre-cooled at 3℃ for 1 day and placed in a gas-tight chamber with 0%, 30%, or 50% of CO₂ concentration for 3 hours at 3℃. Next, 400 g of the oyster mushroom sample was packaged into 20-㎛ thick oriented polypropylene (OPP) film bags and stored at 4℃ for 21 days. Treatment with 30% of CO₂ treatment maintained the highest stipe firmness of the oyster mushrooms during storage. The stipe lightness (CIE L^⁎) was the highest at 14 and 21 days, while the stipe yellowness (CIE b^⁎) was the lowest at 2 and 7 days of storage. Therefore, we concluded that the 30% CO₂ treatment maintained the overall visual quality of the 'Gonji-7ho' oyster mushroom until 17 days of storage at 3℃. Our results suggest that the shelf life of 'Gonji-7ho' oyster mushroom could be extended by the postharvest application of 30% CO₂ for 3 hours during low temperature storage.

• Korean Journal of Food Science and Technology
• /
• v.39 no.4
• /
• pp.380-385
• /
• 2007

This study was basic research to improve the existing method far distributing just harvested and sail-clad fresh ginseng. The quality of surface-washed fresh ginseng was compared to that of muddy fresh ginseng during storage at 0, 5, 10, and $20^{\circ}C$. After 45 days of storage, there was no difference in weight loss between the washed ginseng and the control at $0^{\circ}C$, but the loss was 46% and 37% lower in the washed than the control at $5^{\circ}C$ and $10^{\circ}C$, respectively. The ginseng stored at $20^{\circ}C$ after washing had less deterioration than the control stored at $10^{\circ}C$ for the same period. The sensory characteristics of the washed ginseng showed better quality scores ranging from 6.8 to 8.2, while the control ranged from 5.7 to 6.9 after 45 days of storage at $10^{\circ}C$. The washed ginseng had less viable cells, mold and yeast, and coliforms at 0.87, 1.55, and 0.95 log units, respectively, compared to the control, and this trend was maintained in the washed ginseng throughout storage.

• Journal of the Korean Wood Science and Technology
• /
• v.34 no.1
• /
• pp.15-22
• /
• 2006

ln order to manage efficiently many ancient wooden buildings, which have been preserved as cultural properties in Korea, the internal state of wood members should be evaluated exactly and periodically by a NDE (non-destructive evaluation) method. A research project was planned to develop an X-ray CT (computed tomography) system as a NDE method for wood, which could be easily applied in field. This paper includes the first part of this project. First of all, to establish a measuring procedure of wood density using X-ray radiography, the correlation between X-ray intensity and the film brightness was evaluated. Also, initial X-ray intensity was quantified with various radiate conditions controlled by the tube voltage and tube current. And then, the effects of density, annual ring angle, and thickness on the mass attenuation coefficient of wood were examined. Finally, Beer's law was modified with the above results and adopted to calculate the density of wood. As a result of this study, the measuring procedure of wood density was established using a portable soft X-ray device and this procedure was verified with some small wood specimens. This results will he used valuably for the following researches to develop a portable X-ray CT system.

• Korean Journal of Food Science and Technology
• /
• v.26 no.2
• /
• pp.133-137
• /
• 1994

Functional properties of packaging films prepared with cellulose derivatives were measured. As a presolvation treatments of celluloses, 95% ethanol solution for methylcellulose (MC), hydroxypropyl-methylcellulose (HPMC) and ethylcellulose (EC) and water for hydroxypropyl cellulose (HPC) were used. For film sheeting, the ethanol concentration of final cellulose solution should exceed 50% for MC, HPMC and HPC and 80% for EC. Thickness and functionalities of the prepared films were varied by type, molecular weight and viscosity of the cellulose and kind of plasticizer used. Tensile strength of MC, HPMC and HPC films were $67.7{\sim}275.4\;MPa$, $124.6{\sim}260.0\;MPa$, and $14.8{\sim}29.4\;MPa$, respectively. The strength of MC and HPMC films was higher than that of low density polyethylene (LDPE) films $(13.1{\sim}27.6\;MPa)$. Solubility of the cellulose films varied widely by plasticizer used and the films containing polyethyleneglycol (PEG) as a plasticizer was more soluble than the films by glycerol. Maximum water vapor permeability and oxygen permeability of the cellulose films was more than 1,000 folds and less than one-twelfth of the LDPE film, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.42 no.4
• /
• pp.716-722
• /
• 2017

In this paper, a fully printed NFC tag operating at 13.56 MHz was designed and fabricated using silver nano-paste and carbon ink. The proposed NFC tag has a printed coil with an inductance of $2.74{\mu}H$ on a PI film for application to an NFC tag IC with an internal capacitance of 50 pF. Screen printing technology used in this paper has advantages such as large area printing for mass production, low cost and eco-friendly process compared to conventional PCB manufacturing process. The proposed structure consists of a circular coil implemented as a single layer using silver nano-paste and carbon ink, a jumper pattern for chip mounting between the outer edge and the center of the coil, and an insulation pattern between the coil and the jumper pattern. In order to verify the performance of the proposed NFC tag, we performed the measurements of the printing line width, thickness, line resistance, adhesion and environmental reliability, and confirmed the suitability of the NFC tag based on the full-printed manufacturing method.