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排序方式: 共有164条查询结果,搜索用时 31 毫秒
1.
Seong-Sik Myoung Yongshik Lee Jong-Gwan Yook 《Microwave Theory and Techniques》2007,55(7):1531-1538
This paper proposes a bandwidth-compensation method for miniaturized filters based on short-ended parallel coupled lines. Capacitive loading of such coupled lines is a relatively simple means of reducing the line lengths. In this study, a method is developed that predicts exactly the degree of reduction in the fractional bandwidth due to miniaturization. Using this method, the fractional bandwidth of the prototype coupled line filter can be adjusted, enabling miniaturized filters to maintain the targeted fractional bandwidth. The proposed bandwidth-compensation method applies for any type of filters with coupled lines realized with various transmission lines, with uniform or nonuniform line lengths. Experimental results are also presented that verify the validity of the method. 相似文献
2.
Park Joo Hyun Lee Jong-Woo Um Jong-Seok Yook Juhye Kim Kwangki Lim Soon-Bum 《The Journal of supercomputing》2021,77(6):6381-6407
The Journal of Supercomputing - Although Digital Accessible Information System, an international digital talking book standard, is conducting active research on upper level education for people... 相似文献
3.
Byoung Ok Cho Chang Wook Lee Yangkang So Chang Hyun Jin Si Yong Kang Dong Sub Kim Kwon Il Seo Hong Sun Yook Il Yun Jeong 《Food science and biotechnology》2014,23(4):1313-1319
The protective effect of cyanidin-3-glucoside (C3G) against carbon tetrachloride (CCl4)-induced liver injury in mice was investigated. Administration of C3G attenuated the levels of serum aspartate aminotransferase, alanine aminotransferase, and liver lipid peroxidation in CCl4-treated mice. Histopathological examination of mouse livers showed that C3G reduced the incidence of liver lesions induced by CCl4. Moreover, C3G prevented DNA damage and decreased the protein levels of γ-H2AX in CCl4-treated mouse livers. C3G also increased the activity of the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase, which were decreased due to CCl4 administration in CCl4-treated mouse livers. C3G inhibited the expression levels of IL-6 and iNOS in CCl4-treated mice. C3G apparently protects the liver from CCl4-induced hepatic damage through antioxidant and anti-inflammatory mechanisms. 相似文献
4.
The current efficiency of polymer light-emitting diodes (PLEDs) were improved using a quantum dot interlayer between a hole transport layer and an emitting layer. The quantum dot interlayer played a role of controlling the hole transport in the PLEDs and enhanced the charge balance in the emitting layer. The current efficiency of the PLEDs was increased by more than 20% by the quantum dot interlayer. In particular, the efficiency improvement was significant at high luminance due to reduced efficiency roll-off in the quantum dot-embedded PLEDs. 相似文献
5.
This study was undertaken to determine if gamma irradiation can circumvent the need for sodium nitrite to obtain and maintain the desired color of pork loin ham. A dose of 5 kGy was observed to be as effective as the use of 200 ppm of sodium nitrite to provide and maintain the desired color of the product for 30 days. Peroxidation of the product was reduced with addition of sodium nitrite but increased with irradiation. However, organoleptic quality of the irradiated ham without added sodium nitrite was acceptable. 相似文献
6.
Scanning tunneling microscopy (STM) has been employed to investigate the chirality of monophosphine compounds that are highly efficient chiral ligands in transition-metal-catalyzed organic transformations. The absolute configuration of 1-(2-diphenyphosphino-1-naphthyl)isoquinoline enantiomers with axial chirality was discriminated directly by the "marker" group, PPh(2) substitutes. Although the two enantiomer molecules adsorb on a Cu(111) surface and form well-defined (4 x 4) structures, the positions of PPh(2) substitutes in the molecular adlayers are different. The mirror symmetry between two adlayers is demonstrated. On the basis of STM results, structural models are proposed to interpret the chiral adsorption. The results presented here supply a straightforward method for axial chirality analysis in adsorbed adlayers by STM. 相似文献
7.
Jung-Min Kim Kun-Wook Kim Jong-Gwan Yook Han-Kyu Park 《Electronics letters》2001,37(16):995-996
A meander-type slot antenna fed by a stripline is proposed for use in miniaturised personal communication systems. By varying the slot configuration of the antenna, a 56% smaller antenna to substitute the conventional slot antenna is achieved. Simulated and measured results are presented 相似文献
8.
Improved efficiency in green phosphorescent organic light-emitting diodes using a composite hole transport layer (HTL) with hole transport and exciton blocking function was investigated. Mixed layer of (4,4′-N,N′-dicarbazole)biphenyl (CBP) and N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB) was used as a HTL and quantum efficiency could be enhanced from 4.3% to 8.1% at 100 cd/m2. Best performances could be obtained in the device with 50% CBP and 50% NPB in the HTL. 相似文献
9.
Soon Ok Jeon Kyoung Soo Yook Chul Woong Joo Jun Yeob Lee 《Journal of Industrial and Engineering Chemistry》2009,15(4):602-604
White organic light-emitting diodes (WOLEDs) were fabricated by using a blue emitting layer combined with quantum dot (QD) based color converting materials. Orange emitting QD was used as a color converting material and effective color conversion was realized. A white color coordinate of (0.32, 0.41) was obtained with a current efficiency of 8.3 cd/A at 1000 cd/m2. 相似文献
10.
Ponchak G.E. Donghoon Chun Jong-Gwan Yook Katehi L.P.B. 《Advanced Packaging, IEEE Transactions on》2000,23(1):88-99
LTCC MCM's for RF and wireless systems often use metal filled via holes to improve isolation between the stripline and microstrip interconnects. In this paper, results from a 3D-FEM electromagnetic characterization of microstrip and stripline interconnects with metal filled via fences for isolation are presented. It is shown that placement of a via hole fence closer than three times the substrate height to the transmission lines increases radiation and coupling. Radiation loss and reflections are increased when a short via fence is used in areas suspected of having high radiation. Also, via posts should not be separated by more than three times the substrate height for low radiation loss, coupling, and suppression of higher order modes in a package 相似文献