上海交通大学：《生物传热学教与学 Bioheat Transfer》课程教学资源（电子讲义）lecture 11 Measurement of Thermal Properties for biological tissue

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 thermo￾graphy