Impact of the Sensor Temperature on Low Acetone Concentration Detection Using AlGaN/GaN HEMTs

In this work, we report on AlGaN/GaN HEMT sensors for acetone concentration below 100ppm and in a broad range of the sensor temperature varying from RT to 300 ∘C. At RT, in the presence of acetone, a smooth and monotonic decrease of the current is observed with a rather large response of 15A/ppm and with a large response time (several minutes) and memory effect. At a high temperature (300 ∘C), a current decrease is first observed just after the acetone injection, then followed by an increase, which saturates and stabilizes at a constant value. In order to clarify this unexpected behaviour, a detailed study of the sensor response versus the temperature and acetone injection flow is carried out. The outcome of this investigation is that a competition between the current variations induced by both the sensor and gas flow temperature difference from one side and the acetone dipolar moment from the other side can explain this transient. Our study highlights that AlGaN/GaN HEMT-based sensors allow for very sensitive acetone detection at both room and high temperatures. Nevertheless, care must be taken during the characterization and operation of such sensors especially at high operating temperatures. On the other hand, the high temperature operation helps to improve the sensor response and suppress the memory effect.

Download Full-text

DISPERSED PHASE VELOCITY IN A HIGH-TEMPERATURE GAS FLOW

High Temperature Material Processes An International Quarterly of High-Technology Plasma Processes ◽

10.1615/hightempmatproc.2019030506 ◽

2019 ◽

Vol 23 (4) ◽

pp. 319-328

Author(s):

Dmitry V. Nesterovich ◽

Oleg G. Penyazkov ◽

Yu. A. Stankevich ◽

M. S. Tretyak ◽

Vladimir V. Chuprasov ◽

...

Keyword(s):

High Temperature ◽

Phase Velocity ◽

Gas Flow ◽

Dispersed Phase ◽

High Temperature Gas

Download Full-text

Passive Auto-Focus Algorithm for Correcting Image Distortions Caused by Gas Flow in High-Temperature Measurements of Surface Phenomena

Image Processing & Communications ◽

10.2478/v10248-012-0068-1 ◽

2012 ◽

Vol 17 (4) ◽

pp. 379-384 ◽

Cited By ~ 2

Author(s):

Krzysztof Strzecha ◽

Tomasz Koszmider ◽

Damian Zarębski ◽

Wojciech Łobodziński

Keyword(s):

High Temperature ◽

Gas Flow ◽

Temperature Measurements ◽

Surface Phenomena ◽

Auto Focus ◽

High Temperature Measurements

Abstract In this paper, a case-study of the auto-focus algorithm for correcting image distortions caused by gas flow in high-temperature measurements of surface phenomena is presented. This article shows results of proposed algorithm and methods for increasing its accuracy.

Download Full-text

CLC 18.10LN

Alloy Digest ◽

10.31399/asm.ad.ss0950 ◽

2006 ◽

Vol 55 (1) ◽

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

Shear Strength ◽

High Temperature ◽

Austenitic Stainless Steel ◽

Stainless Steels ◽

The Other ◽

Low Carbon ◽

Good Corrosion Resistance ◽

Temperature Performance

Abstract CLC 18.10LN is an austenitic stainless steel with 18% Cr, 9.5% Ni, and 0.14% N to provide good corrosion resistance at strengths above the other low-carbon stainless steels. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and shear strength as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, machining, and joining. Filing Code: SS-950. Producer or source: Industeel USA, LLC.

Download Full-text

Exploring the Effect of Silicon on the High Temperature Corrosion of Lean FeCrAl Alloys in Humid Air

Oxidation of Metals ◽

10.1007/s11085-020-10019-2 ◽

2021 ◽

Author(s):

T. Sand ◽

A. Edgren ◽

C. Geers ◽

V. Asokan ◽

J. Eklund ◽

...

Keyword(s):

Corrosion Resistance ◽

High Temperature ◽

Oxidation Behavior ◽

High Temperature Corrosion ◽

The Other ◽

Oxide Scales ◽

Protective Oxide ◽

New Approach ◽

Fecral Alloys ◽

Cr Evaporation

AbstractA new approach to reduce the chromium and aluminium concentrations in FeCrAl alloys without significantly impairing corrosion resistance is to alloy with 1–2 wt.% silicon. This paper investigates the “silicon effect” on oxidation by comparing the oxidation behavior and scale microstructure of two FeCrAl alloys, one alloyed with silicon and the other not, in dry and wet air at 600 °C and 800 °C. Both alloys formed thin protective oxide scales and the Cr-evaporation rates were small. In wet air at 800 °C the Si-alloyed FeCrAl formed an oxide scale containing mullite and tridymite together with α- and γ-alumina. It is suggested that the reported improvement of the corrosion resistance of Al- and Cr-lean FeCrAl’s by silicon alloying is caused by the appearance of Si-rich phases in the scale.

Download Full-text

Interferential comparison of the red and other radiations emitted by a new cadmium lamp and the michelson lamp

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1933.0014 ◽

1933 ◽

Vol 139 (837) ◽

pp. 202-218 ◽

Cited By ~ 4

Keyword(s):

Fine Structure ◽

High Temperature ◽

Wave Length ◽

The Other ◽

Reference Standard ◽

Definite Evidence ◽

Electro Magnetic ◽

The Many ◽

Red Radiation ◽

Red Line

It is now generally recognised that future definitions of the units of length will probably be based on the length of a wave of visible light. At present the wave-length of the red radiation of cadmium serves as the basis of all measurements of the lengths of electro-magnetic waves which are perceptible by optical means, and provisional sanction has been given to measurements of length on the same basis, as an alternative to direct reference to the metre. Whether the cadmium red radiation provides the best reference standard for all measurements of length has not yet been definitely established. Two international committees, one representing spectroscopists and the other metrologists, have sanctioned standard specifications for cadmium lamps of the Michelson type from which the red radiation may be produced. The two specifications differ from one another in certain details, but both are subject to the same objections. These objections are directed partly against the high temperature at which it is necessary to run the lamp and partly against the high voltage required to excite the radiation. Therefore, such hyperfine structure and asymmetry as may be present in the red line of cadmium is likely to be masked in the Michelson lamp by a combination of two phenomena —the enhanced Doppler effect due to the high temperature of the radiating cadmium atoms, and the effect of the moderately high intensity of the electric field. Were this not so, it might be somewhat surprising that no definite evidence of fine structure or asymmetry had so far been observed in the red line from the Michelson lamp, notwithstanding the many careful examinations, with the aid of the most sensitive interferometers, to which this line has been subjected, in view of its importance as the reference standard for all other wave-lengths. Recently Nagaoka and Sugiura have recorded that they have observed slight evidences of structure in the red radiation when excited under special conditions in which great precautions were taken to ensure extreme sharpness of the line. It is believed, however, that no subsequent confirmation of this effect has yet been published.

Download Full-text

Analysis of the hot gas flow in the outlet plenum of the very high temperature reactor using coupled RELAP5-3D system code and a CFD code

Nuclear Engineering and Design ◽

10.1016/j.nucengdes.2007.06.008 ◽

2008 ◽

Vol 238 (1) ◽

pp. 274-279 ◽

Cited By ~ 22

Author(s):

Nolan Anderson ◽

Yassin Hassan ◽

Richard Schultz

Keyword(s):

High Temperature ◽

Gas Flow ◽

Hot Gas ◽

Very High Temperature Reactor ◽

High Temperature Reactor ◽

Very High

Download Full-text

Comparative Study of GaN Growth Process by MOVPE

MRS Proceedings ◽

10.1557/proc-572-463 ◽

1999 ◽

Vol 572 ◽

Author(s):

Jingxi Sun ◽

J. M. Redwing ◽

T. F. Kuech

Keyword(s):

High Temperature ◽

Comparative Study ◽

Gas Phase ◽

Residence Time ◽

Gas Flow ◽

Flow Sheet ◽

Flow Zone ◽

High Quality ◽

Phase Temperature ◽

High Temperature Gas

ABSTRACTA comparative study of two different MOVPE reactors used for GaN growth is presented. Computational fluid dynamics (CFD) was used to determine common gas phase and fluid flow behaviors within these reactors. This paper focuses on the common thermal fluid features of these two MOVPE reactors with different geometries and operating pressures that can grow device-quality GaN-based materials. Our study clearly shows that several growth conditions must be achieved in order to grow high quality GaN materials. The high-temperature gas flow zone must be limited to a very thin flow sheet above the susceptor, while the bulk gas phase temperature must be very low to prevent extensive pre-deposition reactions. These conditions lead to higher growth rates and improved material quality. A certain range of gas flow velocity inside the high-temperature gas flow zone is also required in order to minimize the residence time and improve the growth uniformity. These conditions can be achieved by the use of either a novel reactor structure such as a two-flow approach or by specific flow conditions. The quantitative ranges of flow velocities, gas phase temperature, and residence time required in these reactors to achieve high quality material and uniform growth are given.

Download Full-text