The　recent　report　of　room-temperature　superconductivity　at　near-ambient　pressure　in　nitrogen-doped　lutetium　hydride(Lu-H-N)by　Dasenbrock-Gammon　et　al.[Nature　615,244-250(2023)]has　attracted　tremendous　attention　due　to　its　anticipated　great　impact　on　technology.However,the　results　could　not　be　independently　reproduced　by　other　groups　worldwide　in　follow-up　studies,which　elicited　intense　controversy.Here,we　develop　a　reliable　experimental　protocol　to　minimize　the　extensively　concerned　extrinsic　influences　on　the　sample　by　starting　the　reaction　from　pure　lutetium　loaded　with　an　H2/N2　gas　mixture　in　a　diamond　anvil　cell　under　different　pressures　and　temperatures　and　simultaneously　monitoring　the　entire　chemical　reaction　process　using　in　situ　four-probe　resistance　measurements.Therefore,we　could　repeatedly　reproduce　the　near-room　temperature　upsurge　of　electrical　resistance　at　a　relatively　early　stage　of　the　chemical　reaction.However,the　mechanism　is　suggested　to　be　a　metal-to-semiconductor/insulator　transition　associated　with　the　structural　modulation　in　the　non-stoichiometric　Lu-H-N,rather　than　superconductivity.