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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

ANTENNA CONTROL FOR TT&C ANTENNA SYSTEMS

Kaiser, Julius A., Herold, Fredrick W. 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / A thinned array sensor system develops error voltages for steering dish antennas from signals arriving over a broad range of angles, thereby eliminating need for a priori knowledge of signal location.
2

The Use of Polydimethylsioxane in Liquid Crystal Device with Confined Structure

Chen, Ming-Yang 02 September 2011 (has links)
PDMS has not only the characteristics of good chemical and physical properties,flexible, low surface free energy, and good optically transparent, also has the advantages of low cost, low toxicity and environmental protection. In this study we use PDMS to fabricate liquid crystal device with different micro-confined structures. We had a discussion about liquid crystal in the micro-confined structure through optical textures and measured electro-optical characteristics on our device. Through the experiment we found the liquid crystal device with micro-confined structure had not only the characteristics of wide viewing angle and contrast ratio has been up to standard in normal display. And it also demonstrated the capability in flexible liquid crystal display.
3

Vertical Field Switching Blue Phase Liquid Crystals For Field Sequential Color Displays

Cheng, Hui-Chuan 01 January 2012 (has links)
Low power consumption is a critical requirement for all liquid crystal display (LCD) devices. A field sequential color (FSC) LCD was proposed by using red (R), green (G) and blue (B) LEDs and removing the lossy component of color filters which only transmits ~30% of the incoming white light. Without color filters, FSC LCDs exhibit a ~3X higher optical efficiency and 3X higher resolution density as compared to the conventional color filters-based LCDs. However, color breakup (CBU) is a most disturbing defect that degrades the image quality in FSC displays. CBU can be observed in stationary or moving images. It manifests in FSC LCDs when there is a relative speed between the images and observers’ eyes, and the observer will see the color splitting patterns or rainbow effect at the boundary between two different colors. In Chapter 2, we introduce a five-primary display by adding additional yellow(Y) and cyan(C) colors. From the analysis and simulations, five primaries can provide wide color gamut and meanwhile the white brightness is increased, as compared to the three-primary. Based on the five-primary theorem, we propose a method to reduce CBU of FSC LCDs by using RGBYC LEDs instead of RGB LEDs in the second section. Without increasing the sub-frame rate as three-primary LCDs, we can reduce the CBU by utilizing proper color sequence and weighting ratios. In addition, the color gamut achieves 140% NTSC and the white brightness increases by more than 13%, as compared to the three-primary FSC LCDs. Another strategy to suppress CBU is using higher field frequency, such as 540 Hz or even up to 1000 Hz. However, this approach needs liquid crystals with a very fast response time (

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