gas sensors
The reason we take Nox as target gas
1. NOx is harmful to human health in its own right.
2. NOx reaction produces tropospheric ozone.
3. NOx causes acid rain, smog, and destruction of forests.
- This problems become more serious due to the rapid increase of car.
Sensitivity
▪ Temperature
▪ Catalyst
▪ Large surface area
▪ Low carrier concentr
hightemperatures, high-temperature
membrane and separation processes, heat exchangers, and heat storage media. Design aspects and safety are also important for high-temperature processes.
-Thermo-chemical water splitting
For example, Thermo-chemical water splitting is the conversion of water into hydrogen and oxygen by a series of thermally driven chemical reactions. Thermo-chemical water
reaction in apples or potatoes, etc. Some preservation methods require foods to be sealed after treatment to prevent recontamination with microbes; others, such as drying, allow food to be stored without any special containment for long periods.
Common methods of applying these processes include drying, spray drying, freeze drying, freezing, vacuum-packing, canning, preserving in syrup, sugar c
high frequency) or at variable frequencies between 1KHz to 1 MHz
-The dc bias VG is slowly varied to get quasi-continuous C-V characteristics
② C-V characteristics of MOS-capacitor on p- and n-type Si
The C-V data depends on the measurement frequency as well.
[Figure 11] Measured C-V characteristics on an P-type, N-type Si
2.4 Graph shifting
In MOS structure, we should consider non
temperature transformation diagram): 온도, 시간, 변태곡선
3) 표면 경화법
① 화학적 표면 경화법
ⅰ) 침탄법: 고체(목탄, 코우크스), 가스(CO,CO2,메탄,에탄,프로판), 침탄깊이 0.5~2mm
ⅱ) 시안화법: KCN, NaCN (청화법)
ⅲ) 질화법: NH3, 50~100 Hr, 자동차의 크랭크축, 캠, 펌프축 등에 사용. 질화층 0.4~0.8mm
* 특징