提升宝宝视觉一空间智力的良方.ppt

The system will finally approach a state in which all the external parameters remain constant. Such state is called equilibrium state If the system has gradients(梯度) of macroscopic parameters (P,V,T), such a state is referred to as a non-equilibrium state The process from a non-equilibrium state to a equilibrium state is called relaxation (弛豫) Relaxation 选择物理量“密度”。考虑上例中两个部分的密度变化。设初始时刻的密度分别为n = n0和n = 0。平衡后的密度为共同的n?。弛豫过程如图： 结　论 当时间变化为t = ? 时，温度的幅度变化为1/e。 If we slow down the rate of relaxation process, and assume that there will be enough time for the parameters to equalize over the entire system. Therefore: 非平衡过程是由连续不断的无穷小间隔的平衡态构成。这种用平衡态描述非平衡过程的方法被称之为： 　准 静 态 quasi-state 系统特征： 由于分子处于不停的热运动之中，所谓的平衡只是一种热动平衡。 宏观系统的物理量是在平衡值附近涨落的统计结果。 在线性代数中，一个3*3的方阵，如果其秩为2，其结论？ 1.行列式的值为0； 2.两个独立变量； 3.第三个变量可以用以上两个变量线性表示。 Thermodynamic Units 热力学单位 牛(N) =kg m s-2 压强：帕斯卡Pa (N m-2) 1大气压强 (pn)= 101325 Pa 能量： 焦耳(J) 1J = 1N m 　　　　(见中文教材P6) 2. Temperature. The temperature principle 热平衡定律和温度 Temperature is a rather subjective (主观的) term(术语)-degree of hotness of body. But, the term can be given a more objective meaning through a easily measured physical parameters depending on the degree of hotness. Examples: (测量温度的物质) height of the column of liquid mercury in a glass tube (汞柱); the pressure of a gas in a constant volume vessel; the resistance of a conductor; the emissive power of a red-hot body, etc. The limit of applicability(应用的限制): Mercury solidification point(凝固点); gas condensation point(凝聚点)； fusion point of metal(金属熔点)。 The fields of application of these thermometers overlap(重叠)。 Thermostat, 恒温热源 The concept of the thermostat: a thermostat has heat capacity(热容) greater than that of any reference bodies. When contact, the temperature of thermostat does not change and , on the other hand, any reference body acquires its temperature after a short relaxation time. (恒温热源的温度不变，与其接触的物体瞬时达到恒温热源的温度) Adiabatic wall(