A data strobe signal generating device includes a preamble controller configured to generate a preamble signal enabled in synchronization with a first clock signal and disabled in synchronization with a second clock signal after an output enable signal is enabled, and a data strobe signal output unit configured to generate a data strobe signal in response to the preamble signal. The pn junction has a bottom junction at the bottom of the n-type region and a side junction at the peripheral side face. lithium aluminum silicate, by which treatment it is transformed into \u03b2-spodumene, which is more advantageous for further processing; in the method, concentrate or ore with a grain size of 20-1,000 \u03bcm is processed in a fluidized bed reactor, at a temperature of 800-1,000\xb0 C.