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2 GHz 평면 테이퍼형 전력 분배/결합회로의 수정된 구조 연구
한용인,김인석 한국전자파학회 2002 한국전자파학회논문지 Vol.13 No.10
본 논문에서는 2 GHz 대역에서 하나의 입력과 다수의 출력을 가지는 [10]에서 제시 한 평면 Taper 혈의 전력 분배/결합기의 수정한 구조와 접지평면에 PBG(Photonic Band Cap) 구조를 적용한 형태의 전력 분배/결합 회로를 제안한다. 제안하는 구조의 전기적 특성을 걱정하는 파라메터들을 HFSS 시뮬레이션을 이용하여 분석하였다. 입력 정한 그리고 각 출력 판에서 출력 신호의 균형과 위상의 선형성을 위해 회로의 중앙에 하나의 원형 모양을 에칭 제거하였다. 또 본 논문에서 제안한 구조의 1:2와 1:3 전력 분배 / 결합기와 [10]의 구조와 5-Parameter를 비교ㆍ분석하였다. 결과적으로 본 연구에서 제시하는 수정된 형태를 적용할 경우 기존의 전력 분배/결합기의 반사손실 특성이 2 GHz에서 20 dB 이상 개선되었고. 이에 추가하여 PBG 구조를 적용하면 또 18 dB 이상 개선된 특성을 보였다. 대역폭 또한 증가되는 것을 확인하였다. In this paper, a 2 GHz tapered shape of multiport power divider/combiner modified from the model published by [10] and adopted PBG(Photonic Band Gap) structure is proposed. Parameters determining electrical property of the circuit structure have been analyzed by HFSS simulation. For input matching, balance of output signals and phase linearity at each output port, one circular hole has been etched out on the circuit surface. 1:2 and 1:3 power dividers/combiners designed by this study have been compared with the same circuits designed by the method of [10] in terms of S-parameters. As a result, it has been found that tile modified structure and PBG of power divider/combiner have improved return loss more than 20 dB and another 18 dB. respectively, at 2 GHz.
Zea mays 불검화추출물을 함유하는 정제의 제제설계 및 평가
한용해,정연복,한건,정석재,박만기,심창구,Han, Yong-Hae,Chung, Youn-Bok,Han, Kun,Chung, Suk-Jae,Park, Man-Ki,Shim, Chang-Koo 대한약학회 2000 약학회지 Vol.44 No.6
The purpose of the present study was to design and prepare the optimum formulation for the oral administration of titrated extract of the unsaponifiable fraction of Zea mays L. (ETIZM). For this purpose, we simulated the blood concentration of ETIZM after its oral administration, changing the dissolution rate constants $(0.05{\sim}20\;hr^{-1})$. In vivo parameters, such as absorption rate constant $(k_a)$, elimination rate constant (k) and volume of distribution (Vd), were incorporated in the simulation on the basis of the experiments and literatures. When the dissolution rate constant $(k_r)$ is over $5\;hr^{-1}$, the absorption process appears to be the rate limiting step for the transport of ETIZM from the G.I. ract to the blood circulation. While less than $5\;hr^{-1}$, the dissolution rate considered to be the rate limiting step. Moreover, the optimum blood concentration was shown in the range from 1 to $5\;hr^{-1}$ of $k_r$ in the simulation. To design and prepare the tablets on the basis of the above results, 7 formula containing HPMC, PEG 4000 and PEG 6000 (1-5%, respectively) were prepared and evaluated. The tablets containing PEG 4000 (1%), PEG 6000 (1%) or PEG 4000 (5%) satisfy the optimum $k_r$ range ($1-5\;hr^{-1}$). These formulations, therefore, will be able to show the more effective blood concentration, compared with the commercial products after the oral administration.
상온에서 RF 스퍼터링 방법으로 증착한 Hafnium Oxide 박막의 저항 변화 특성
한용,조경아,윤정권,김상식,Han, Yong,Cho, Kyoung-Ah,Yun, Jung-Gwon,Kim, Sang-Sig 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.9
In this study, we fabricate resistive switching random access memory (ReRAM) devices constructed with a Al/$HfO_2$/ITO structure on glass substrates and investigate their memory characteristics. The hafnium oxide thin film used as a resistive switching layer is sputtered at room temperature in a sputtering system with a cooling unit. The Al/$HfO_2$/ITO device exhibits bipolar resistive switching characteristics, and the ratio of the high resistance (HRS) to low resistance states (LRS) is more than 60. In addition, the resistance ratio maintains even after $10^4$ seconds.
Determination of the toxicity of enrofloxacin on mouse bone marrow cells
한용,주홍구 한국예방수의학회 2019 예방수의학회지 Vol.43 No.4
Enrofloxacin (EFX) is one of the 2nd generation quinolone antibiotics and is now widely used as a broad-spectrum antibiotic for industrial animals. Previous study showed that EFX reduces the cellular metabolic activity of spleen cells and modulates the inflammatory responses. However, little is known about its toxicity on bone marrow (BM) cells. In this study, BM cells were treated with EFX and cellular metabolic activity, cell death, the change of neutrophil (CD11b+Gr1+ cells) proportion, and antigen uptake ability of granulocytes were measured. Compared to the control, EFX-treated cells showed the decrease of cellular metabolic activity, the increase of cell death, and the decreased proportion of neutrophils. In contrast, the antigen uptake ability of granulocytes in BM cells was increased by EFX. These data suggest that EFX has only limited toxicity on BM cells. And also, EFX is safe on BM cells in a range of concentration, 6.25 – 25 μg/mL. This study can provide available data for the safety or toxicity of EFX.