[열전달] Unsteady state, One dimension, Double layer

열전달현상을 미분방정식으로 표현했을 때도 이런 형태의 방정식이 된다.rm Partial T over Partial t = k over rho C v BULLET Partial ^2 T over Partial x ^2 = alpha Partial ^2 T over Partial x ^2 이제 이런 미분방정식의 해를 구하는 방법은 두가지 방법으로 나누어진다.① explicit method (양함수법)미분방정식을 수치해석적으로 푸는 방법은 Taylor 급수에서 유도된다.Taylor 급수의 일반 식은 다음과 같다.f(x)= sum n=0 ^INF f ^(n) (a) over n! (x-a) ^n식을 전개

state, process, and equilibruim(물성치, 상태, 과정, 그리고 평형)*Properties - macroscpic characteristics of system(물성치) mass, volumme, energy, pressure, temp(P, V, T, E, m)- assigned @ given time- Thermodyamics deals with quantities(상태) rather than properties- independent of path*state - specified by providing the value of the properties(열역학적 상태)- using relations among properties*process - transformation one state to another with change of properties(과정) - if dФ/dt=0 -> stead state*Cycle -a sequence of processes which begins and end at the s

전달되는 열량 | | | | +- To surroundings의 온도| ++-+ +- T - system의 온도+- | |계가 주위에 dW의 일을 하는 이 과정에 대해서 dS계 ≥ dQ over T라고 할 수 있다. 그리고 주위의 관점을 두고 보았을 때 dS주위 = -dQ over T subo∴ 총 엔트로피의 변화는 dS계 + dS주위 ≥ dQ( 1 over T - 1 over T subo )가 된다.주위에서 계로 열이 전달될 때 To > T ∴ (1 over T - 1 over T subo ) > 0 dQ over To∴ dS계 + dS주위 ≥ 0 만약 계에서 주위로 열이 전달된다면, 즉 To < T 이고 dQ

one thing to identify dimensions of teacher professionalism that ideally should be in place in order to realise the raft of ambitious educational aims now expected of schools and teachers. It is quite another to predict that these will come about as widespread norms of practice. Their chances of success anyway depend in part on a range of forces outside the direct reach of either teachers or education authorities. But, it is important to move beyond advocacy of ideals to outline how these might be implemented in practice.For education authorities much depends on how far they really want scho

one thing to identify dimensions of teacher professionalism that ideally should be in place in order to realise the raft of ambitious educational aims now expected of schools and teachers. It is quite another to predict that these will come about as widespread norms of practice. Their chances of success anyway depend in part on a range of forces outside the direct reach of either teachers or education authorities. But, it is important to move beyond advocacy of ideals to outline how these might be implemented in practice.For education authorities much depends on how far they really want scho