Under Kim, who rose to power following his father's death in 2011, North Korea has seen steady progress in its nuclear and missile programs, including two nuclear tests this year. It recently claimed a series of technical breakthroughs in its goal of developing a long-range nuclear missile capable of reaching the continental United States.
Easily processed materials with the ability to transport excitons over length scales of more than 100 nanometers are highly desirable for a range of light-harvesting and optoelectronic devices. We describe the preparation of organic semiconducting nanofibers comprising a crystalline poly(di-n-hexylfluorene) core and a solvated, segmented corona consisting of polyethylene glycol in the center and polythiophene at the ends. These nanofibers exhibit exciton transfer from the core to the lower-energy polythiophene coronas in the end blocks, which occurs in the direction of the interchain π-π stacking with very long diffusion lengths ( 200 nanometers) and a large diffusion coefficient (0.5 square centimeters per second). This is made possible by the uniform exciton energetic landscape created by the well-ordered, crystalline nanofiber core.
Puerto Rico is still recovering from Hurricane Maria several months later, but it should have the benefit of thoroughly modern networks as it returns to health. T-Mobile now plans to roll out its 600MHz Extended Range LTE networking in the US territory this fall. This should provide more coverage and capacity than you sometimes see on the mainland (it has twice the range of "mid-band" LTE, T-Mobile claimed) as long as you have a compatible device. The hardware is also "5G-ready," T-Mobile said, suggesting that Puerto Rico will be prepared for the provider's speed upgrade within the next two years. The 600MHz network could give T-Mobile a competitive advantage and help it corner the Puerto Rican market.