Inorganic phosphor
○ A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence.
○ Phosphors are often transition metal compounds or rare earth compounds of various types.
○“Classical” inorganic phosphors usually consist of a host lattice with activator ions doped into it in small concentrations, typically a few mole percent or less.
Host lattice &
properties
investigating transition metal oxides
specific morphologies
nanostructured materials
→ the charge storage from faradaic processes occurring at the surface of the material
→ the pseudo-capacitive effect, becomes increasingly important
mesostructured materials
→ enhanced oxidation and reduction kinetics
→ the relatively short diffusion path length for ions and electrons
VO₂Property
융 점 : 1545℃
전이온도 : 68℃
전이온도 이하 : Monoclinic
전이온도 이상 : Tetragonal rutile
M I T Theory
MIT - 모트 금속 부도체 전이(Mott metal Insulator Transition)
전자의 운동을 변화 시킴에 따라 갑자기 절연체에서 금속으로 또는 금속에서 절연체로 전이하는 것
Mott insulator
-전도 전
carbide와 같은 단결정의 표면 위에 epitaxial growth 시키는 방법이다. Silicon Carbide를 1100℃이상으로 가열시키면 이것이 그래핀으로 환원된다. 이때, 사용되는 Silicon carbide의 표면에 의해 그래핀의 두께, mobility, carrier density 등에 큰 영향을 미친다.
또 다른 방법으로는 metal substrate를 이용해 epitaxial growth 시킬
1. IMPATT Diode의 정의.
IMPATT Diode는 IMPact ionization Avalanche Transit Time Diode의 줄임말로, 주로 높은 주파수를 사용하는 전기제품이나 마이크로파를 사용하는 장치 등에서 쓰이는 높은 출력을 낼 수 있는 다이오드이다. IMPATT Diode는 breakdown field가 높은 silicon carbide로 만들어지는 것이 보통이다. 주로 3~100GHz정
Metals
52.90
151.28
Machinery
105.80
131.63
Strong
Industry Analysis
Industry Analysis
Weakness
More import than export
90% of medicine몶s raw materials is defending on import
We call it Generics.
Adverse condition
Transition of per GNI
Industry Analysis
Opportunity
Korea economy is growing.
Medical Costs
1999
2000
2001
2002
2003
2004
Whole
Population
222
1314
1782
1906
2053
2236
Over-65
24
229
metal fences are preferred in most places because they do not block visibility into the property, are less susceptible to graffiti, and are more difficult to climb. The fences should be at least 6 feet high. Horizontal bars should be located only at the top and bottom. Walls along sidewalks and property lines should be constructed only where there is a need for privacy or street noise mitigation.
transitions and they are usually less energetic than gamma rays.
X-rays with varying energies are generated by machines.
→ To produce the X-rays, a beam of electrons is directed at a thin plate of gold or other metal, producing a stream of X-rays.
Like gamma rays,
X-rays can pass through thick foods,
require heavy shielding for safety.
Like E-beams,
Chapter 15
Extrusion and Drawing of Metals
Direct-Extrusion
Figure 15.1 Schematic illustration of the direct-extrusion process.
Extrusions and Products Made from Extrusions
Figure 15.2 Extrusions and examples of products made by sectioning off extrusions. Source: Courtesy of Kaiser Aluminum.
Types of Extrusion
Figure 15.3 Types of extrusion: (a) indirect; (b) hydrostatic; (c) lateral;
Process Var