CGPM 2003CCAUV reportPresident- Dr. Joaqun Valdés (.ppt

1、1,CGPM 2003 CCAUV reportPresident: Dr. Joaqun Valds (CIPM) Executive Secretary: Dr. P. Allisy-Roberts (BIPM),2,CCAUV first meeting July 1999CCAUV second meeting October 2001CCAUV third meeting October 2002 28 delegates, 5 observers and 1 guest,3,CCAUVSummary of Comparison Status,4,Acoustics,5,Ultras

2、ound,6,Vibration,7,8,Classification of Services in AUV Document CCAUV 02 - 05,9,Future Needs for Metrology in AUV Report prepared by NPL (UK), PTB (Germany), IEN (Italy) and the President of CCAUV Document CCAUV 02 - 33,10,AUV and Nanotechnology Need to develop ever smaller transducers,11,12,Achievi

3、ng vibrational quantum limits with nanomembranes,New standards with acoustical or thermal phonons?,PHONON EMISSION ONE BY ONE,13,Schematic diagram of micromachined stereocilia mounted on a membrane, with piezoresistive strain sensors to measure deflection due to microflows (W. Tang).,Array of microm

4、achined stereocilia.,14,In the CCAUV section of the BIPM website there are documents of restricted access. Most of them will be now be open for free access. There is also an extense list of publications related to AUV.,15,The unit one, the neper and the bel,16,Logic A (current logic),The ratio of tw

5、o quantities of the same kind is a new quantity.,17,Logic B,Division of one quantity by other of the same kind merely express the number of times one quantity fits into the other.This number may be just called a coefficient, a factor or a ratio, but not a new quantity.No need to assign SI units to n

6、umbers!,18,Logic A or Logic B? It is a matter of choice,19,PROBLEMS associated with Logic A,CONFUSION between levels, reference levels and the underlying quantities and SI unitsCONFUSION through special namesCONFUSION through the use of the special name decibel with different power and field quantities such as dB(mW), dB(W), dB(0.775V), dB(V), dB(mA), dB(mV/m), dB(W/m2), dB(W/4kHz), dB(W/K), dB(W/m2kHz), dB(kHz), dB(Pa), dB(Pa/V), dB(mV/Pa) and dB(K-1),20,The best recommendation should be to use more the accepted SI units underlying such ratios or levels as bel or neper,