Measurement of Thermal Properties for biological tissue
Measurement of Thermal Properties for biological tissue
Temperature Measurement ·Thermometer probe o Sensitivity o Accuracy o Stability o Response time o Passivity o Size
Temperature Measurement • Thermometer probe Sensitivity Accuracy Stability Response time Passivity Size
Liquid-in-glass (volume change) o Mercury ●-380Cto356oC o Ethyl alcohol low temperature (down to -200C)
Liquid-in-glass (volume change) Mercury -38 oC to 356 oC Ethyl alcohol low temperature (down to -200 oC)
Platinum Resistance Thermometer o Resistance change R(刀/R(To)=1+aT+bT2
Platinum Resistance Thermometer Resistance change R ( T)/ R(T 0) = 1 + a T + bT2
Thermal Couples o Seebeck effect: when a conductor is placed in a temperature gradient,electrons diffuse along the gradient and an emf or thermal voltage is generated BLACKENED JUNCTION METAL 1 Y SHIELDED VOLTMETER REFERENCE JUNCTION 1区 METAL2 affected by:electromagnetic fields AT=∑ay" Precision:0.1C n=0 as fine as 10um in diameter
Thermal Couples Seebeck effect: • when a conductor is placed in a temperature gradient, electrons diffuse along the gradient and an emf or thermal voltage is generated • affected by: electromagnetic fields Precision: 0.1 o C as fine as 10um in diameter 0 N n n n T aV
Thermistor o Semi Conductor o=exp(AE/kT) 1 R= O① =4+4InR+4(InR) Precision can reach 0.01C
Thermistor Semi Conductor 3 0 1 2 0 ln (ln ) 1 1 exp( / ) A A R A R T R E kT Precision can reach 0.01oC
Fiber Optic Thermometers o liquid crystal sensor Intensity of the reflected light change due to temperature o LiTaO(钽酸锂)crystal ●Birefringence(双折射)direction dependent on temperature o Other Crystals or phosphors decay time of fluorescence
Fiber Optic Thermometers liquid crystal sensor Intensity of the reflected light change due to temperature LiTaO 3 (钽酸锂)crystal Birefringence( 双折射）direction dependent on temperature Other Crystals or phosphors decay time of fluorescence
Other thermometers o Other electronic devices o Quartz thermometer (resonant frequency) o Liquid Crystal indicator
Other thermometers Other electronic devices Quartz thermometer (resonant frequency) Liquid Crystal indicator
Thermography o Principle:Scanning emitted infrared radiation Intensity on the surface g=EAoT o Soft Tissue Trauma Muscle Strain(bruised tissue),blood perfusion change
Thermography Principle: Scanning emitted infrared radiation Intensity on the surface Soft Tissue Trauma Muscle Strain (bruised tissue), blood perfusion change 4 s q ε A σ T
o Precision analysis of IR thermo- graphy
Precision analysis of IR thermography