instruction:
In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
question:
Which of the following is NOT a goal of phorphor LED development: higher light output, optical losses, or higher operation temperatures?, Context: 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.
answer:
optical losses


question:
Which place has the lowest latitude according to the text?, Context: At the end of World War II Soviet troops occupied southern Sakhalin Island and the Kuril Islands, making them part of the RSFSR. The status of the southernmost Kurils remains in dispute with Japan.
answer:
southernmost Kurils


question:
Blackbody photons make it impossible to achieve what?, Context: In quantum mechanics and quantum field theory, the vacuum is defined as the state (that is, the solution to the equations of the theory) with the lowest possible energy (the ground state of the Hilbert space). In quantum electrodynamics this vacuum is referred to as 'QED vacuum' to distinguish it from the vacuum of quantum chromodynamics, denoted as QCD vacuum. QED vacuum is a state with no matter particles (hence the name), and also no photons. As described above, this state is impossible to achieve experimentally. (Even if every matter particle could somehow be removed from a volume, it would be impossible to eliminate all the blackbody photons.) Nonetheless, it provides a good model for realizable vacuum, and agrees with a number of experimental observations as described next.
answer:

QED vacuum


