General says he'll come up with $150 million if scientists produce mobile device within 18 months.A two-star Army general threw down a challenge last week to Lawrence Livermore scientists: He will beat the bushes for more than $150 million if scientists can build the world's first mobile battle laser for test firing in 18 months. Livermore laser engineer Bob Yamamoto had been begging for this chance. But Livermore, specializing in nuclear explosives, never has built a full-up, firing weapons system for the battlefield. "Eighteen months is very aggressive, and I'm saying that very politely," said Yamamoto. On Tuesday, Major Gen....