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Among the challenges being faced to improve the efficiency of LED-based white light sources is the development of more efficient phosphors. As of 2010, the most efficient yellow phosphor is still the YAG phosphor, with less than 10% Stoke shift loss. Losses attributable to internal optical losses due to re-absorption in the LED chip and in the LED packaging itself account typically for another 10% to 30% of efficiency loss. Currently, in the area of phosphor LED development, much effort is being spent on optimizing these devices to higher light output and higher operation temperatures. For instance, the efficiency can be raised by adapting better package design or by using a more suitable type of phosphor. Conformal coating process is frequently used to address the issue of varying phosphor thickness.

What can improve the efficiency of LED-based white light?
Answer: more efficient phosphors
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Nishimura's force consisted of two battleships, one cruiser and four destroyers. Because they were observing radio silence, Nishimura was unable to synchronize with Shima and Kurita. Nishimura and Shima had failed to even coordinate their plans before the attacks – they were long-time rivals and neither wished to have anything to do with the other. When he entered the narrow Surigao Strait at about 02:00, Shima was 22 miles (40 km) behind him, and Kurita was still in the Sibuyan Sea, several hours from the beaches at Leyte. As they passed Panaon Island, Nishimura's force ran into a trap set for them by the U.S.-Australian 7th Fleet Support Force. R. Adm. Jesse Oldendorf had six battleships, four heavy cruisers, four light cruisers, 29 destroyers and 39 PT boats. To pass the strait and reach the landings, Nishimura had to run the gauntlet. At about 03:00 the Japanese battleship Fusō and three destroyers were hit by torpedoes and Fusō broke in two. At 03:50 the U.S. battleships opened fire. Radar fire control meant they could hit targets from a much greater distance than the Japanese. The battleship Yamashiro, a cruiser and a destroyer were crippled by 16-inch (406 mm) shells; Yamashiro sank at 04:19. Only one of Nishimura's force of seven ships survived the engagement. At 04:25 Shima's force of two cruisers and eight destroyers reached the battle. Seeing Fusō and believing her to be the wrecks of two battleships, Shima ordered a retreat, ending the last battleship-vs-battleship action in history.

Which Japanese admiral was a  rival of Nishimura?
Answer: Shima
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Disagreements following the war have resulted in stalemate punctuated by periods of elevated tension and renewed threats of war. The stalemate led the President of Eritrea to urge the UN to take action on Ethiopia with the Eleven Letters penned by the President to the United Nations Security Council. The situation has been further escalated by the continued efforts of the Eritrean and Ethiopian leaders in supporting opposition in one another's countries.[citation needed] In 2011, Ethiopia accused Eritrea of planting bombs at an African Union summit in Addis Ababa, which was later supported by a UN report. Eritrea denied the claims.

What did Eritrea do when it was accused of planting bombs at the African Union summit?
Answer:
denied the claims