North Korea\'s growing dependence on China, reflected by the launch of new joint economic zones along their border, drives a wedge among parties seeking to curb North Korea\'s nuclear weapons drive, experts here said Friday. Jonathan Pollack, a senior fellow at the Brookings Institution, pointed out that China is taking advantage of the flexible implementation of the U.N. Security Council resolution adopted in 2009 to punish Pyongyang for its second nuclear test.