热力学与统计物理 金晓峰 复旦大学物理系 2005-4-13 2021/8/21
2021/8/21 1 热力学与统计物理 金晓峰 复旦大学物理系 2005-4-13
Figure 34.6 temprature heat of normal and super- conducting aluminum. The al pha below T, by application of a weak (300-gauss) magnetic tick which d superconducting but has otherwise negligible fect on the specific heat, The Debye temperature is quite specific heat is dominated b the clectronic contribution throughout this temperature range (as can be seen from the fact that the normal-state curve is quite close to be linear). 'The discontinuity at T agrees well with the theo 34.22) ⊥h1」11 Ies-cn/c,=1,43. Well be 1.07 2.0 low T c, drops far bel resting the existen gy gap. (N, E. Phillips, Phys. Rer. 114. 676
AGISE 21-3 Eucerin tuttepnershiririte ten leHI 绝热 d 绝热 (e, a, b) FIGURE 20-6 The Otto cycle
绝热 绝热 (e, a, b)
Iste fine .ow pressure (liquid) 器静A四 Ex . xpansion igh pressure (liquid 如 teaming datare COoling coils Valve Condenser coils (inside Outside FIGURE 20-9(a)Typical refrigerator)Sensor refrigerator) refrigerator system. The compressor motor forces a gas at high pressure through a heat exchanger (to outside) a→ (condenser)on the outside walls of the refrigerator where QH is given i from off and the gas cools to become Inside liquid. The liquid passes from a high-pressure region to soils to low-pressure tubes on the inside Low pressure walls of the refrigerator; the liquid High pressure evaporates at this lower pressure and ap thus absorbs heat(2.)from the inside of the refrigerator. The fluid returns to the compressor where the cle begins again. (b)Schematic diagram, like Fig 20-8 Compressor Plug Motor pl motor ug
Example 4
Example 4
ompressor t ejection Heat exchanger Expansion engine === Working volume TTTTTTTTTTTTTTT Figure 12.1 Simple expansion refrigerator. A working gas is compressed; the heat of compression is ejected into the environment. The compressed room temperature gas is precooled further in the counterflow heat exchanger. It then does work in an expansion engine, where it cools to a temperature below that of the working volume. After extracting heat from the working volume, the gas returns to the compressor via the heat exchanger
P2 水冷凝器 日T1 H 围 压缩 机 (a)焦耳一汤姆孙实验 (b)节流过程 图4.20
H=const 400 200 inversion curve 200 0200400600800 P(10°bar) Figure 4.10. Experimental inversion curve and isenthalpic(H= const )for nitrogen
t°C 600 400 致区 200 致区 tc200 100 200 300400P(atm) 图 5-15
To and from compressor or precooling stages Heat exchanger Figure 12.3 The Linde cycle. Gas is liquefied y combining Joule-Thomson expansion with a counterflow heat exchanger JT expansion valve Liquefied gas
