来到健身房，教练首先让他握住一个小仪器，说是要测量体内脂肪含量。王先生使用的体脂仪类似一个秒表，使用时，只需用手握住，就能测出具体数值。对此，他有些疑惑：“这么一个东西，能准确测出来吗？”记者注意到，市面上出售的体脂仪大部分利用的是阻抗原理测脂肪比例，这种方法的*术语叫做“BIA”，其原理是脂肪组织因水分含量低而不导电，肌肉等细胞组织因含水量高而导电性能好，由此根据的电阻抗推定脂肪和其他组织的比例。
PV023R1K1T1NHCC
PV023R1K1T1VMMC
PV023R1K1T1WMRC
PV023R9K1T1NFWS
PV023R1K1JHNMMC
PV023R1K4T1NFHS
PV023R1L1T1NMMC
PV023R1K8T1VMMC
PV023R1K1T1NFRZ
PV023R9K1T1NMMC
PV023R1K4T1NMR1
PV023R1K1T1VFDS
PV023R1K8T1NMMC
PV023R1K8T1NFWS
PV023R1K1T1WMR1
PV023R1K8T1N001
PV023L1K1T1NMMC
PV023R1K4T1NMMC
PV023R1K1T1NKLC
PV023R1K4T1NFR1
PV023R1K1S1NFWS
PV023R1K1T1NFFC
PV023L1K1T1NFWS
PV023R1K1T1WFDS
PV023R1K1T1NFFP
PV023R1L1T1NF
PV023R1K1T1WMM1
PV023R1K1T1NHLC
PV023R1K1T1NMRZ
PV023R1K1T1NMRK
PV023R1K1T1WMMC
PV023R1K1T1NFF1
PV028R1K1T1N001
PV028R1K1T1N100
PV028R1K1T1NFDS
PV028R1K1T1NFR1
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PV028R1K1T1NMMC
PV028R1K1T1NMM1
PV028R1K1T1NMRC
PV028R1K1T1NFWS
PV028R1K1T1NFRC
PV028R1K1T1NFF1
PV028R1K1T1WMM1
PV028R1K1T1WFR1
PV028R1K8T1NFWS
PV028R1K4T1NFR1
PV028R1K1T1VMMC
PV028R1K1T1NHCC
PV028R1K4T1NMMC
PV028R1K1T1NELC
PV028R1K1T1NHLC
PV028R1K8T1N001
PV028R1K1T1NF
PV028R9K1T1NFWS
PV028R9K1T1NMMC
PV028R1K1T1VFDS
PV028R1K1AYNMRZ
PV028R1K8T1NMMC
PV028R1K1T1NMRK
PV028R1K1T1NFFP
PV028L1K1T1NMMC
PV028R1K1T1NFRZ
PV028R1K1S1NFWS
PV028R1K1T1NMMZ
PV028R1K1T1NMR1
PV028R1K1T1NMFC
PV028R1K1T1WFDS
PV028L1K1T1NFWS
PV028R1K1JHNMMC
PV028R1K1T1NMRZ
PV028R1K4T1NFHS
PV028R1K1T1NMF1
PV028R1K1T1NGLC
PV028R1K1T1WMRC
PV028R1L1T1NMMC
PV028R1K1T1WMMC
PV028R1K1T1WMR1
PV028R1K8T1VMMC
PV028R1K1T1NFFC
PV028R1K1T1NMMK
PV028R1K4T1NMR1
PV032R1K1T1N001
PV032R1K1T1N100
PV032R1K1T1NFDS
PV032R1K1T1NFR1
PV032R1K1T1NFHS
PV032R1K1T1NMMC
PV032R1K1T1NMM1
PV032R1K1T1NMRC
PV032R1K1T1NFWS
PV032R1K1T1NFRC
PV032R1K1T1NFF1
PV032R1K1AYNMTZ
PV032R1K1T1NMFC
PV032R1K1T1NMR1
PV032R1K1T1NMF1
PV032R1K1T1NMRK
PV032R1K1T1NFFP
PV032R1K1T1WMMC
PV032R1K4T1NMMC
PV032R1K8T1VMMC
PV032R1K1T1WFR1
PV032R1K1T1NFFC
PV032R1K1JHNMMC
PV032R1K1T1WMRC
PV032R9K1T1NFWS
由于电网有一定的阻抗，电网的阻抗包括，变压器的阻抗Z0，线路的阻抗Z1和Z2，的阻抗就Z=(Z0+Z1+Z2)。当设备1向电网注入谐波电流时(记为In)，则在电网的阻抗Z上产生了谐波电压(记为Un)，于是设备2的电源输入端就出现了谐波电压Un。如果谐波电压过了设备2能够承受的程度，设备2就会受到这个谐波电压的干扰。一般电子设备允许的谐波畸变率为UTHD5%。在现实中，设备1往往是中频炉、变频器、直流电机驱动器等工作电流发生剧烈变化的设备，设备2往往是PL数控机床、计算机、精密测量仪器等设备。
