• Title/Summary/Keyword: Negative Permeability

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Resonant Wireless Power Transfer System with High Efficiency using Metamaterial Cover (메타구조 기반의 고효율 공진형 무선전력전송 시스템)

  • Kim, Hyoungjun;Seo, Chulhun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.1
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    • pp.47-51
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    • 2014
  • In this paper, unit cell and arrayed cover for improving the transfer efficiency of resonant wireless power transfer system is proposed. We used the characteristic of zero refractive index for focusing a magnetic field between the transmitting resonator and receiving resonator. For zero refractive index, we designed the unit cell structure that have a negative value of effective permeability. The size of proposed unit cell based on metamaterial structure is $70mm{\times}70mm{\times}3.2mm$, operating frequency is 13.56 MHz. And, the size of arrayed cover is $400mm{\times}400mm{\times}3.2mm$, is consists of 2-layers. The transfer efficiency of the proposed wireless power transfer system are 94.8 %, 93.2 %, 91.4 %, 90.8 % at 100 mm, 200 mm, 300 mm and 400 mm (distance between transmitting and receiving resonator), respectively. And proposed WPT system has a transfer efficiency high than 90 % over the overall distances.

Standardization and Evaluation of Performance Textiles through the Consumer's On-line Reviews - Focused on Summer Knit Shirts Containing Cellulose Fibers - (인터넷 구매후기를 통한 의류제품 소재평가표준화와 소재성능평가 - 셀룰로오스 섬유를 함유한 여름용 니트 티셔츠를 중심으로 -)

  • Kwak, Soo-Kyung;Lee, Ji-Yeon;Park, Myung-Ja
    • Journal of the Korea Fashion and Costume Design Association
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    • v.18 no.2
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    • pp.177-190
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    • 2016
  • On-line consumer reviews are good references for consumers to evaluate and buy apparel products. The objective of this study is to facilitate communication about performance textiles between consumers and merchandisers who buy and sell apparel products on online. The survey was based on standardizing words used in consumer reviews written after purchase of summer knit t-shirts at internet shopping mall and evaluating the performance textiles including cellulose fibers. We collected reviews of five sorts of the clothing products including cotton/modal, tencel/polyurethane, polyester/rayon, linen, cotton and selected 1000 reviews related to textiles. For classifying each word used in the reviews by the performance textiles, they were quantified applying same standards. The results were as follow: First, the standard for consumer to consider importantly was tactile sensation, appearance, pilling, thickness, dimensional stability in washing. Second, the important category of performance textiles was healthy-comfort and psychological-comfort. Third, there were difference performance textiles for consumer to recognize, e.g. cotton/modal was important to air-permeability, tencel/polyurethane was noticed about tactile sensation, polyester/rayon was perceived about pilling unlike other things, linen had a problem of clothing care-convenience, then cotton was familiar fiber to important for appearance. The last, consumers usually focused on writing the most positive or negative online reviews. Although not familiar with professional terminologies, consumers are sensitive to physical properties of textiles. Therefore, standardizing and evaluating performance textiles are expected to improve satisfaction as providing objective information to consumers considering in buying apparel products at online shopping mall and increase in revenue to manufacturer.

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A Design of Novel Compact Microstrip Bandstop Filters Based on Split-Ring Resonators and Spiral Resonators (Split-Ring 공진기와 Spiral 공진기를 이용한 새로운 소형의 마이크로스트립 대역 저지 필터 설계)

  • Lee, Jong-Hyuk;Oh, Young-Chul;Myung, Noh-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.7
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    • pp.796-808
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    • 2007
  • In this paper, two novel compact microstrip bandstop filters using complimentary split ring resonators(CSRRs) and spiral resonators is proposed. The first one is the bandstop filter using an array of CSRRs etched on the center line of a microstrip. The bandstop is due to the presence of negative effective permittivity and positive permeability near resonant frequency which prevent the wave propagation. The second on is the bandstop filter using an array of spiral resonators etched on the center line of a microstrip. The bandstop is due to the self-resonance of spiral circuit. We have achieved controllable resonance frequency and bandwidth, super compact dimension, low insertion losses in the passband and high level of rejection in the stopband with sharp cutoff. The electrical sizes of two proposed filter are very small. Additionally, they can be easily fabricated and compatible with MMIC or PCB technology.

Analysis of Wildlife Moving Route with Landscape Characteristics (경관의 특성에 따른 동물의 이동경로에 관한 연구)

  • Lee, Dong-Kun;Park, Chan;Song, Won-Kyong
    • Journal of Environmental Impact Assessment
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    • v.17 no.2
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    • pp.133-141
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    • 2008
  • The loss, alteration, and fragmentation of habitat have led to a reduction of biodiversity. The growing awareness of the negative effects of habitat fragmentation on natural systems has resulted in conservation strategy that is concerned with not only population and habitat level but also ecosystem and landscape level. Especially, ecological network to link core areas or major habitat patches is one of the most important issues. Recently, landscape connectivity is increasingly used in decision making for fragmented landscape management in order to conserve the biodiversity in the regional scale. The objective of this study was to find potential forest as a ecological corridor in Go-yang city, Gyung-gi province using cost-distance modelling method that can measure connectivity based on animal movement. 'Least cost-distance' modelling based on functional connectivity can be useful to establish ecological network and biodiversity conservation plan. This method calculates the distance modified with the cost to move between habitat patches based on detailed geographical information on the landscape as well as behavioural aspects of the animal movement. The least cost-distance models are based on two biologically assumptions: (1) dispersers have complete knowledge of their surroundings, and (2) they do select the least cost route from this information. As a result of this study, we can find wildlife moving route for biodiversity conservation. The result is very useful for long-term aspect of biodiversity conservation plan in regional scale, because this is reflection of geographical information and behavioural aspects of the animal movement.

The Analysis of Actual State of Working Environment and Working Uniforms for Burning Waste Workers (생활폐기물 소각장 작업자의 작업환경과 작업복 현황 분석)

  • 박순자;신정숙;정명희
    • Journal of the Korean Society of Clothing and Textiles
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    • v.27 no.8
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    • pp.992-1003
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    • 2003
  • This study analyzes the actual state of the working uniforms worn by burning waste workers to protect their body from the hazardous environment. Directions for improvement of the clothing fabrics is also suggested. We visited and interviewed those persons who worked in the burning waste plant in Seoul and in Gyunggi Province. 245 workers were surveyed by questionnaires, and 211 workers out of 245 were statistically analyzed. Frequencies and percentages were calculated and $\chi$$^2$ test, ANOVA and Scheffe Post hoc comparison methods were utilized to test some hypothesis. The working uniforms were classified as four general types: separate type, disposable-coverall. overall, and winter clothes. At present, the working uniforms are not suitable for the conditions which they are used. There is a lack of ventilation and an inability to absorb perspiration limited elasticity, and the uniforms are prone to static shock. The degree of satisfaction varied significantly, based on the worker's educational background and main work. However, only a small percentage of workers interviewed were satisfied with the appearance and the fit of the present working uniforms. The working duration had a negative impact on the satisfaction of the worker. This results suggest that materials, colors, design and size of working clothes must be improved. The suggestions are as follows: Firstly. to use disposable non-woven fabrics finished to increase moisture regain. Secondly. to use the bad air permeability fabrics to protect the skin from absorbtion of harmful gases, flying dust, heavy metals, etc.

Antibacterial properties of quinolones

  • Yoshida, Hiroaki
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1997.04a
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    • pp.40-47
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    • 1997
  • New quinolones generally have a broad antibacterial spectrum against gram-positive, gram-negative, glucose-nonfermenting and anaerobic bacteria. Some of newly developed quinolones have potent activities against S. aureus including MRSA, S.pneumoniae including PRSP, B. fragilis, chlamydiae, mycoplasmas and mycobacteria as well, and show good activities against various strains resistant to antibacterial agents of other classes. Quinolones display postantibiotic effects in vitro and are bactericidal at concentrations similar to or twice that of the minimum inhibitory concentrations (MICs) for susceptible pathogens. In experimental murine infection models including systemic infections with various pathogens such as S. aureus, S. pyogenes, S. pneumoniae, E. coli and P. aeruginosa, quinolones have shown good oral efficacy as well as parenteral efficacy. Good oral absorption and good tissue penetration of quinolones account for good therapeutic effects in clinical settings. The target of quinolones are two structurally related type II topoisomerases, DNA gyrase and DNA topoisomerase IV. Quinolones are shown to stabilize the ternary quinolone-gyrase-DNA complex and inhibit the religation of the cleaved double-stranded DNA. Bacteria can acquire resistance to quinolones by mutations of these target enzymes. Mutation sites and amino acid changes in DNA gyrase and DNA topoisomerase IV are similar in the organisms examined, suggesting that the mechanism of quinolone resistance in the target enzymes is essentially the same among various organisms. Quinolones act on both the target enzymes to different degrees depending on the organisms or agents tested, and bacteria become highly resistant to quinolones in a step-wise fashion. Incomplete cross-resistance among quinolones in some strains of E. coli and S. aureus suggests the possibility of finding quinolones active against quinolone-resistant strains which are prevailing now. To find such quinolones, the potency toward two target enzymes and the membrane permeability including influx and/or efflux systems should be taken into account.

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Clinical Observation and Therapeutic Evaluation of Rh-endostatin Combined with DP Regimen in Treating Patients with Advanced Esophageal Cancer

  • Deng, Wen-Ying;Song, Tao;Li, Ning;Luo, Su-Xia;Li, Xiang
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.16
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    • pp.6565-6570
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    • 2014
  • Objective: To observe the curative effects of rh-endostatin combined with DP regimen in treating patients with advanced esophageal cancer and analyze the correlation of CT perfusion (CTP) parameters and the expression of vascular endothelial growth factor (VEGF). Methods: Twenty patients with esophageal cancer confirmed pathologically were randomly divided into combined treatment (rh-endostatin+DP regimen) group and single chemotherapy group, 10 patients in each group, respectively. All patients were given conventional CT examination and CTP imaging for primary tumor. The level of VEGF, the size of tumor and CTP parameters (BF, BV, PS and MTT) before treatment and after 2 cycles of treatment were determined for the comparison and the correlation between CTP parameters and VEGF expression was analyzed. Results: the therapeutic effect of rh-endostatin+DP regimen group was superior to single chemotherapy group. VEGF level after treatment in rh-endostatin+DP regimen group was obviously lower than single chemotherapy group (P<0.01). The expression of VEGF had positive correlation with BF and BV but negative correlation with MTT. Compared with treatment before for rh-endostatin+DP regimen group, BF, BV and PS decreased while MTT increased after treatment (P<0.05). However, there were no significant differences between treatment before and after treatment in single chemotherapy (P>0.05). Conclusions: Rh-endostatin can down-regulate the expression of VEGF in esophageal cancer, change the state of hypertransfusion and high permeability of tumor vessels and had the better curative effect and slighter adverse reactions when combined with chemotherapy.

Effect of Extreme Rainfall on Cut Slope Stability: Case Study in Yen Bai City, Viet Nam

  • Tran, The Viet;Trinh, Minh Thu;Lee, Giha;Oh, Sewook;Nguyen, Thi Hai Van
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.4
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    • pp.23-32
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    • 2015
  • This paper addresses the effects of extreme rainfall on the stability of cut slopes in Yen Bai city, Northern Viet Nam. In this area, natural slopes are excavated to create places for infrastructures and buildings. Cut slopes are usually made without proper site investigations; the design is mostly based on experience. In recent years, many slope failures have occurred along these cuts especially in rainy seasons, resulting in properties damaged and loss of lives. To explain the reason that slope failure often happens during rainy seasons, this research analyzed the influence of extreme rainfalls, initial ground conditions, and soil permeability on the changes of pore water pressure within the typical slope, thereafter determining the impact of these changes on the slope stability factor of safety. The extreme rainfalls were selected based on all of the rainfalls triggering landslide events that have occurred over the period from 1960 to 2009. The factor of safety (FS) was calculated using Bishop's simplified method. The results show that when the maximum infiltration capacity of the slope top soil is less than the rainfall intensity, slope failures may occur 14 hours after the rain starts. And when this happens, the rainfall duration is the deciding factor that affects the slope FS values. In short, cut slopes in Yen Bai may be stable in normal conditions after the excavation, but under the influence of tropical rain storms, their stability is always questionable.

CRLH Rectangular Waveguide with Balanced Condition above Cut-off Frequency (차단 주파수 이상에서 평형 조건을 만족하는 CRLH 직각 도파관)

  • Kim, Dong-Jin;Lee, Jeong-Hae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.9
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    • pp.912-918
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    • 2011
  • In this paper, a composite right-/left-handed(CRLH) rectangular waveguide satisfying a balanced condition above the cut-off frequency is presented. The proposed structure consists of one shorted stub and two twisted H-plane irises which produce an effectively negative permeability and permittivity, respectively. The CRLH structure can independently control the series and shunt resonance frequencies of a CRLH transmission line which determine the left-handed(LH) and right-handed(RH) bands due to a minimized coupling between a shorted stub and twisted H-plane irises. Thus, the design of the CRLH waveguide satisfying a balanced condition is possible. To analyze the CRLH structure, a crossly connected equivalent circuit is derived. The simulated and measured results confirm that the proposed CRLH waveguide has a transmission property without a band gap among the LH and RH bands.

Thermal Properties on combination of Velvet and Lining (벨벳과 안감의 소재 조합에 따른 의복의 열저항에 관한 연구)

  • 계명대학교의류학과;이욱자;류덕환
    • Journal of the Korean Society of Clothing and Textiles
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    • v.23 no.1
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    • pp.3-13
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    • 1999
  • This study was performed for purpose of getting fundamental information requisite to wear velvet clothes that is more comfortable for the human body and also the environment. It was carried out in a human wearing test and thermal manikin test at the same time in a controlled-condition chamber. The experimental environment had a ambient temperature of 15$\pm$0.5$^{\circ}C$ with the relative humidity at 5$^{\circ}C$$\pm$5% and with air velocity at less that than 0.2m/sec. Velvet differ from common plain weaves in thermal properties because it's constructed in two parts one is ground part and the other part is pile part. In order to investigate the thermal resistance of velvet eight different combination of 4 velvet kinds and 2 lings kinds as experimental clothes. [(4 velvet kinds : Acetate cuprammoium Rayon Cotton Wool) (2 lining kinds : acetate viscose rayon)longrightarrow8 combination: Aa, Av, Ra, Rv, Ca, Cv, Wa, Wv: the simplified character] The results of this study can be summarized as follows : 1. For the regional thermal resistance the differences in eight clothes as well as differences in each part were significant. As a whole the breast part showed the highest thermal resistance and the leg part was higher than the shank part. The rank of the total thermal resistance was put at Wa>Wv>Ca>Cv>Aa>Av>Ra>Rv in this order. 2. Considered clothing microclimate microclimate temperature has a similar tendency to the total thermal resistance. It showed a significance in the differences of eight clothes and each parts. the belly part was highest in every combination. On the other hand for clothing humidity there was a significance between back and breast part only in the human wearing test. 3. It was indicated that CLO value was highly positively correlated with the clothings' weight and showed a high negative correlation with the air permeability.

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