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그라파이트 인터칼레이션 컴파운드가 에폭시 복합재료의 흡,차음성에 미치는 영향
이병찬 ( Byung Chan Lee ),박규대 ( Gyu Dae Park ),최성규 ( Sung Kyu Choi ),김성룡 ( Sung Ryong Kim ) 한국복합재료학회 2015 Composites research Vol.28 No.6
팽창된 그라파이트 인터칼레이션 컴파운드에 에폭시 수지를 주입하여 제조한 복합재료의 흡·차음성을 연구하였다. 관내법을 이용하여 복합재료의 흡음률과 음향투과손실을 측정하였다. 주사전자현미경을 이용하여 에폭시 매트릭스 내부에 그라파이트 인터칼레이션 컴파운드가 무질서한 방향으로 균일하게 분산된 것을 확인하였다. 그라파이트 인터칼레이션 컴파운드 함량이 증가함에 따라 복합재료의 면밀도가 감소하였으며, epoxy/(GIC 20 wt%)복합재료의 면밀도는 순수 에폭시에 비하여 56% 감소하였다. 500~1000 Hz 주파수 영역에서 복합재료의 흡음률은 순수 에폭시에 비해 3배 정도 증가하였다. 그라파이트 인터칼레이션 컴파운드의 함량이 증가함에 따라 복합재료에 포함된 기공의 비율이 증가하여 순수 에폭시에 비하여 복합재료의 음향투과손실이 감소하는 것으로 판단된다. The sound absorption coefficient and sound transmission loss of graphite intercalation compound (GIC) included epoxy composites were investigated. Epoxy resin was infused into the expanded GIC and the impedance tube method was employed to measure the sound absorption coefficient and sound transmission loss. Scanning electron microscopy photographs showed uniform distribution of the GIC in the epoxy matrix. The surface density of epoxy/ GIC (20 wt%) composites decreased about 56% compared to that of pure epoxy. The sound absorption coefficient of composites increased about 3 times at the frequency range of 500~1000 Hz compared to the pure epoxy. The sound transmission loss of composites decreased with increasing the GIC content and it is attributed to the increase of pores in the composites.
박규대,김환용 원광대학교 대학원 2009 論文集 Vol.42 No.-
In this paper, both circularly polarized patch antenna and modified loop antenna were investigated for ultra high frequency of 908.5MHz-914MHz radio frequency identification systems adopted to reader and transponder, respectively. The CP characteristics for reader antenna was realized by using truncation at the edge of patch and the bandwidth of resonance frequency was also enhanced with longer distance between ground plane and radiating patch. Futhermore, overall patch size was reduced to 1.73 times owing to narrow slit consist of inductance component at the radiating patch on RF-4 substrate with dielectric constant of 4.4 materials. The measurements results of fabricated prototype shows that antenna gain of 7.9dBi, 3dB beam width at radiation pattern of 87° and 105° for vertical and horizontal directions, respectively, with 15dB front-to-back ratio. The results shows that the proposed antenna features a compact size, wide impedance bandwidth, moderate gain, and excellent axial ratio. This antenna is well suitable for the applications in RFID readers.