• Title, Summary, Keyword: Microwave property

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Measurement of Permittivity and Moisture Content of Powdered Food at Microwave Frequencies (분말식품의 마이크로파 유전율 및 수분함량 측정)

  • Kim, K.B.;Kim, J.H.;Lee, J.M.
    • Journal of Biosystems Engineering
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    • v.32 no.4
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    • pp.237-246
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    • 2007
  • In this study, the microwave free-space transmission technique was used to measure the dielectric property of powdered food at microwave frequencies. The sample holder was designed and fabricated to transmit the microwave signals ranging from 1 to 15GHz. From the microwave propagation theory the equation expressing the dielectric property of powdered food was derived and validated by standard dielectrics. The dielectric property of powdered food such as wheat flour, coffee powder and milk powder was measured and analyzed. In the uniform range of bulk density of material, the real parts of permittivity of the food samples increased with the increase of moisture content, bulk density and temperature of the samples. The propagation properties such as attenuation and phase shift increased linearly as the moisture density of the food samples increased. As a measuring frequency of the moisture content, the X-band was recommended.

A Study on the Dyeing of Polyester Fabric by Microwave Heating(II) (Microwave가열에 의한 Polyester직물의 염색성에 관한 연구(II))

  • 임수경;김삼수;허만우
    • Textile Coloration and Finishing
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    • v.11 no.3
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    • pp.49-57
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    • 1999
  • The effect of padding solution for the microwave heat dyeing of polyester fabric was studied variously. The dyeing property of polyester fabric varied with the kinds of added chemicals in the padding solution. Polyester fabrics impregnated in aqueous urea solution and aqueous sodium chloride solution for 10 minutes and then dyed for 7 minutes by microwave apparatus(2450 MHz, 700 W) under optimum conditions give good exhaustion. An aqueous solution of urea and a sodium chloride solution was more effective than water as padding solution for microwave heating dyeing. The K/S values of dyed polyester fabric by microwave were significantly affected by the type of solvent added in padding media and its concentration. Added solvents, n-hexane, acetone and dimethyl formamide were also more effective than water as padding media for the microwave heating dyeing. It is assumed that the effect of used solvents on dyeing property of polyester fabrics depends on the solubility parameter difference between solvent and polyester fabric.

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Manufacture of Composite Electromagnetic Absorber using Natural Lacquer Binder (옻을 지지재로 이용한 복합형 전자파 흡수체의 제작)

  • 김동일;최동한;김수정;박우근;송재만;김민정
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.7
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    • pp.756-761
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    • 2003
  • The microwave absorption properties of silicone, chloride polyethylene(CPE), and natural lacquer which is newly suggested in this study as a binder for composite microwave absorber were investigated to develop a superior microwave absorber. MnZn ferrite composite microwave absorbers mixed with them were prepared and their absorption property was investigated. A MnZn ferrite microwave absorber mixed with natural lacquer showed an excellent microwave absorption property in expanded frequency band.

Microwave Heat Dyeing of Polyester Fabric

  • Kim, Sam-Soo;Lee, Su-Gyung m;Ghim, Han-Do;Kim, Joon-Ho;Lyoo, Won-Seok
    • Fibers and Polymers
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    • v.4 no.4
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    • pp.204-209
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    • 2003
  • The effect of padding solution on the microwave heat dyeing of polyester fabric was studied extensively. Polyester fabrics were impregnated in aqueous urea solution and aqueous sodium chloride solution for 10 min and then dyed for 7 min by microwave apparatus (2450 MHz, 700 W) under optimum conditions which provide good exhaustion. Aqueous solutions of urea and sodium chloride showed more effective than water as a padding solution for microwave heat dyeing. The type of solvent added in padding media and its concentration significantly affects the K/S values of dyed polyester fabric. Added solvents such as n-hexane, acetone, and dimethyl formamide were also more effective than 100 % water as padding media for the microwave heat dyeing. It is supposed that the effect of used solvents on dyeing property of polyester fabrics depends on the solubility parameter difference between solvent and polyester fabric.

Electrical Characteristics of Carbon Nanotubes by Plasma and Microwave Surface Treatments

  • Cho, Sang-Jin;Shrestha, Shankar Prasad;Lee, Soon-Bo;Boo, Jin-Hyo
    • Bulletin of the Korean Chemical Society
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    • v.35 no.3
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    • pp.905-907
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    • 2014
  • The plasma and microwave surface treatments of carbon nanotubes that loaded on plastic substrates were carried out with expecting a change of carbon nanotube dispersion by increasing treatment time. The microwave treatment process was undergone by commercial microwave oven (800 W). The electrical property was measured by hall measurement and resistance was increased by increasing $O_2$ flow rate of plasma, suggesting an improvement of carbon nanotube dispersion and a possibility of controlling the resistances of carbon nanotubes by plasma surface treatment. The resistance was increased in both polyethylene terephthalate and polyimide substrates by increasing $O_2$ flow rate. Resistance changes only slightly with different $O_2$ flow treatment in measure rho for all polyimide samples. Sheet resistance is lowest in polyimide substrate not due to high carbon nanotube loading but due to tendency to remain in elongated structure. $O_2$ or $N_2$ plasma treatments on both polyethylene terephthalate and polyimide substrates lead to increase in sheet resistance.

Properties of Bentwood for Esthetic Designing by Microwave and Ammonia Solution Treatment

  • Lee, Won-Hee;Bae, Hyun-Mi
    • Journal of the Korea Furniture Society
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    • v.18 no.4
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    • pp.275-281
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    • 2007
  • This study was carried out to know bending process property of bentwood by treatment methods such as microwave and ammonia solution treatment. Bentwood processing was operated on bending-jig form with 60mm and 100mm radius of curvature (ROC). The species was used to Korean red pine (Pinus densiflora). No significant difference was shown in bentwood processing method on ROC. In treatment method, ammonia solution treatment for bentwood was better in dimensional stability and working ability than that of microwave treatment. However, bentwood stress was reduced with ammonia solution treatment. Color of bentwood surface appearance has a dark tendency in ammonia solution treatment. But it seems to beautiful effect of apparent annual ring is rising esthetically by ammonia solution treatment. To utilize wood as a exterior material for living amenity, it has to be closely examined from various angles including surface property, degree of swelling and shrinkage, drying state, retaining strength, durability, safety, and insect damage.

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Physical Properties Effect of Dry-Heat and Microwave-Cured Acrylic Resins depending on the Irradiation-Induced Changes (유도광선변화에 따른 건식중합과 마이크로파중합 아크릴레진의 물리적 성질영향)

  • Kim, Gyu-Ri
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.7
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    • pp.4388-4397
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    • 2015
  • The purpose of this study was to research the property change of acrylic resins depending on the induced-beam change and research the improved physical property of dry-heat and microwave-cured dental place acrylic resin in order to develop the acrylic resins with the optimum characteristic. As a result of observing flexural rigidity, hardness and color difference, the dry-heat-cured specimens of Vertex RS and Paladent 20 showed ideal property at 5, 15, and 25 kGy irradiation. The microwave-cured specimens of Vertex RS and Paladent 20 showed ideal property at 5 kGy irradiation. The correlation analysis showed a positive correlation among ARD, flexural rigidity (0 418), E coefficient (0.675) and Barcol hardness (0 588). The radiation cure technology is helpful for relieving the contamination caused by the manufacture of polymer composite. It can significantly contribute to the fusion of ultra violet cure technology and nano technology and the improvement of mechanical property without giving effect to the workability of polymer.

The Material Constants and Microwave Absorbing Characteristics of ferroxplana Composite Microwave Absorber (복합 ferroxplana 전파흡수체의 재료정수와 전파흡수 특성)

  • 신재영;오재희
    • Journal of the Korean Magnetics Society
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    • v.1 no.2
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    • pp.49-54
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    • 1991
  • In this study the correlation between material constants and microwave absorbing characteristics of ferroxplana composite microwave absorber used in X-band was investigated. The real part of permeability(${\mu}_{r}'$) was decreased and the imaginary part of permeability(${\mu}_{r}"$) of ferroxplana composite was increased with increaing ferroxplana loading ratio(F/R). The frequency showing maximum attenuation was shifted to lower frequency with increasing absorber thickness. The absorber 2.6 mm thick showed good band width property and 3.2 mm thick showed good attenuation property. From the apphcation of ferroxplana composite's material constants to the region of material constants which satisfy broad band width, it is found that the absorbing characteristics were estimated quantitatively. Estabhshment of material constants' region which satisfies broad band width can make practical application to design of high performance ferrite microwave absorber.

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A Study on the Dyeing of Polyester Fabric by Microwave Heating(I) (Microwave 가열에 의한 Polyester직물의 염색에 관한 연구(I))

  • 서수정;임수경;김삼수
    • Textile Coloration and Finishing
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    • v.10 no.4
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    • pp.7-14
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    • 1998
  • Microwaves are high frequency radiation capable of generating very rapid, uniform and efficient heating of textile material. Microwave heated dyeing of polyester fabric was tried with different solvent systems, irradiation time and dye concentration. Microwave fixation methods were used with 100% water,30% urea, EG and DMF, respectively, pad-baths in which the padded fabrics were exposed over a heated or boiling water bath to maintain sufficient moisture content during irradiation. In order to ascertain the relation between the dyeing property of polyester fabric and the microwave irradiation condition caused by microwave heating, the K/S values and fastness properties of dyed fabrics such as light, washing and sublimation fastness were measured.

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Photoluminescence property of ZnO nanoparticle prepared by microwave irradiation method

  • Sakamoto, Naonori;Ishizuka, Satoshi;Wakiya, Naoki;Suzuki, Hisao
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.788-791
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    • 2008
  • ZnO nanoparticle was successfully prepared by microwave irradiation method in various oxygen/nitrogen ratio atmospheres. The product prepared in a low oxygen ratio atmosphere showed tetra pod shape with high aspect ratio, c/a. PL spectra of the products showed higher UV emission intensity than the others when it was prepared in the atmosphere oxygen/nitrogen=40/60.

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