Bandwidth-Compensation Method for Miniaturized Parallel Coupled-Line Filters

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.     

Korean language math-to-speech rules for digital books for people with reading disabilities and their usability evaluation

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...     

Modeling of hermetic transitions for microwave packages

Two numerical techniques, the finite difference in time domain (FDTD) and the finite element method (FEM) in frequency domain, are employed to characterize microstrip hermetic transition geometries in an effort to investigate high-frequency effects. Measurements performed on these transitions compare favorably with theory. Two different types of transitions have been analyzed from 10 to 25 GHz and have been found to be limited in performance by higher return loss as frequency increases. It is shown that microstrip-through-CPW hermetic transitions in the shielded environment may suffer from parasitic waveguide modes which, however, can be eliminated with the use of vias at appropriate locations. The hermetic wall on top of the CPW section shows a relatively small (≤ 2 dB) effect on the original circuit performance. Similarly, the hermetic bead transition shows good performance at a lower frequency region while it degrades as frequency increases. This indicates the need for very careful characterization of transitions intended for use in microwave and millimeter-wave applications. © 1996 John Wiley & Sons, Inc.     

Cyanidin-3-glucoside ameliorates CCl4-induced liver injury in mice

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.     

Efficiency improvement of polymer light-emitting diodes using a quantum dot interlayer between a hole transport layer and an emitting layer

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.     

The improvement of color and shelf life of ham by gamma irradiation.

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.     

Compact stripline-fed meander slot antenna

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     

Role of mixed hole transport layer with exciton blocking properties in phosphorescent organic light-emitting diodes

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.     

White organic light-emitting diodes using a quantum dot as a color changing material

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.     

The use of metal filled via holes for improving isolation in LTCCRF and wireless multichip packages

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