chapt08_lecture

HBTs and HEMTs for wireless communications and fiber optical communications Quantum dot lasers The development of quantum dots
1990
Quantum confined Stark effect in quantum wells
5. Quantum optoelectronic devices
6. Quantum transport devices
1956 J. Bardeen, W. Brittain, W. Schockley: For inventing the transistors
1900 Planck’s Quantum Theory
d 2k 2k dk 2 2 ( 4 ) 2 (4 ) 2 m 2 dE
2dk 2 2 1 2m dE E
Density of States2-D 3-DFra bibliotek1-D
0
E
0
E
0
E
1 D1D
2m E
D2 D
m 2
D3 D
m 2mE 2 3
Density of States of Various Quantum Structures
Conduction band
k
Heavy hole band
2k 2 E E0 2m
Effective mass is related to the curvature of the energy band
Light hole band
2 m 2 d E dk 2
Electron’s velocity is also related to the band structure

Ribosome
• Puromycin
– Resembles an aminoacyl-tRNA
– Can bind to the A site
– Couple with the peptide in the P site
– Release it as peptidyl puromycin
• If peptidyl-tRNA is in the A site, puromycin will not bind to ribosome, peptide will not be released
• Basic questions were answered about translation in the process of “breaking” the genetic code
18-4
Nonoverlapping Codons
• Each base is part of at most one codon in nonoverlapping codons
– Wobble, the 3rd base of a codon is allowed to move slightly from its normal position to form a non-Watson-Crick base pair with the anticodon
– Wobble allows same aminoacyl-tRNA to pair with more than one codon
• Proteins are made in the aminocarboxyl direction
• This means that the amino terminal amino acid is added first

Introduction to the Theory of Computation
5
Context-Free Grammars
Nov. 11
Example
A context-free grammar
G:
S → aSb S →λ
A derivation:
S ⇒ aSb ⇒ aaSbb ⇒ aabb
Introduction to the Theory of Computation
19
Derivation Trees
Nov. 11
S → AB A → aaA | λ B → Bb | λ
A
S ⇒ AB
S
B
Introduction to the Theory of Computation
21
S → AB A → aaA | λ B → Bb | λ
() ((( ))) (( ))
Introduction to the Theory of Computation
15
Definition: Context-Free Grammars
Grammar Variables
G = (V , T , S , P )
Terminal symbols Start variable
L is context-free
if and only if there is a grammar
G with L = L(G )
Introduction to the Theory of Computation
17
Derivation Order
1. S → AB
2. A → aaA 3. A → λ

d 2i R di i To solve 2 0, two initial conditions are needed. dt L dt LC One possible choice is i (0) and di (0) / dt. Here i(0) I 0 , and di(0) / dt can be got by i(0), v(0) and ( a).
Take v as the variable dv iC ( a ) becomes dt d 2v R dv v 0 2 dt L dt LC
18
Chap 08 Second-Order Circuits
The Source-Free Series RLC Circuit (cont.)
vR (0 ) vo (0 ) vC (0 ) 20 0 vR (0 ) vo (0 ) (b)
vR (0 ) vo (0 ) 3 2 4
(a )
Substituting (b) into (a ) vR (0 ) vo (0 ) 4V
Chap 08 Second-Order Circuits 14
1. The i is continuous (inductor current). 2. The v is continuous (capacitor voltage)
12 i (0 ) 2A, 42 i (0 ) i (0 ) 2A,

Chap 08 Second-Order Circuits
The inductor is treated as a short circuit.
Ch8 Second-Order Circuits
7