???????λ????п? > ?п????? > ?п???? > ?п?????
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2020-05-08
??? ?п?????????? 1 ?????? | ????????????? 2 ?????????????????100?????????μ? 3 ????????????????? 4 ?п??????????????0????????????? 5 ?п?????????????????·??????????
2020-05-08
??? ?п??????? 1 ?п?????????????????????? 2 ???????????????????? 3 ???????????????????????????????? 4 ?п???????????????????? 5 ????????????????????????????????? 6 ??
2020-05-08
??? ?п??????? 1 ?п???????????? ????? 2 ?????????????????? 3 ?п?????????????????????? 4 ?п??????????????? 5 2020?п??????????????????? 6 ?????? | ??????????????
2020-05-08
??·?????????? ???????????е?????·????????????????м??? ??????????????裬???R?? 0???е????????????????????????????????????????????·?????????????? ????????????
2020-04-20
?????? 1???????????????????????????????????????ù?????????????????? ?????????????? ???????????????????????????????????????????????????????????????????????????
2020-04-20
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2020-04-20
1?????????????????? 2???????????о????????????? 3??????????????????? 4??????????????????????
2020-04-20
1??(6??)???T4??1?????С?????б????г???????С?????500 N??????50 s??????????200 m?????10 m??б????? (1)С??????????????? (2)С??????????????????????? (3)С????????????????
2020-04-20
???????????? 1.??????????????????????????????????? ?? 2.?????????λ??????÷??? m ???????????????????????1 ??? 3.??????λ??????1???= 103 ??? 1????= 10-1 ?? 1????= 10-2 ??
2020-04-20
ps.????????????Щ?????±?δ?????????????????? ??????? ???????? ?????????????????·??s??L???L?? ??????????е????????340m/s ????????е????????3 108m/s ????????? ( ???
2020-04-20
?????? ????嵥 1.????????? (1)?????????????????????????????,???????: (2)??????????????,????????????С??б???????,??е??????????????????,????????????,????????????С????
2020-04-20
1.?????????????? ????? ????????????? ?????? (1)???????????????????????????????????????????????????????????????????绰????? (2)????????????????????Χ???????20~20000Hz???
2020-04-20
1?????????????? 1??????? ?? ???壺????????????????????????? ?? ??????????????????????????????????????????????????岻???????????????F = ?????????G ?? ????????С?????????????
2020-04-20
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2020-04-20