Collision Induced Microwave Absorption in N2, CH4, and N2–Ar, N2–CH4 Mixtures at 1.1 and 2.3 cm−1

1974 ◽  
Vol 52 (9) ◽  
pp. 821-829 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
J. L. Urbaniak
Keyword(s):  
Microwave Absorption ◽  
Quadrupole Moment ◽  
Linear Dependence ◽  
Relaxation Times ◽  
High Sensitivity ◽  
Higher Order ◽  
Induced Absorption ◽  
High Q ◽  
Order Dependence

Collision induced microwave absorption is reported in pure N2, N2–Ar, N2–CH4, mixtures, and in pure CH4 in the 35 and 70 GHz regions (1.1 and 2.3 cm−1) at a temperature of 22 °C. The measurements are accomplished using overmoded high Q cavities capable of pressurization of up to 5000 p.s.i.g. The apparatus and method are described. With the high sensitivity attained, the results in pure N2 from 30 → 250 amagat reveal terms in the square and cube of the density from which the relaxation times are calculated. The linear dependence on frequency of the collision induced absorption up to 2.3 cm−1 is established. Higher order dependence on the density is observed in the N2–Ar and N2–CH4 mixtures. Various estimates of the quadrupole moment of N2 are given, making use of earlier results in other frequency regions.

Collision Induced Absorption in N2, CO2, and H2 at 2.3 cm−1

1975 ◽  
Vol 53 (18) ◽  
pp. 1764-1776 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
J. L. Urbaniak
Keyword(s):  
Microwave Absorption ◽  
Loss Factor ◽  
Relaxation Times ◽  
Virial Coefficients ◽  
Low Frequency ◽  
Frequency Region ◽  
Induced Absorption ◽  
Three Body ◽  
Initial Measurement

Collision induced microwave absorption is reported in pure N2, CO2, and H2 in the region of 2.3 cm−1. For N2 the results are taken at temperatures ranging from 208 to 333 K and at densities ranging from 50 to 300 amagat. The parts of the loss factor which are proportional to the square and the cube of the density are found to depend respectively on T−1.55±0.12 and T−2.56±0.44. These results are well explained by the theory which relates the virial coefficients and relaxation times to the loss factor. Both the two and three body relaxation times, τ2 and τ3 follow very closely a T−0.5 dependence. The ratio of τ2/τ3 is found to be 0.83. For CO2 the results are taken at temperatures ranging from 273 to 363 K and at densities ranging from 8 to 80 amagat. The parts of the loss factor which are proportional to the square and cube of the density depend respectively on T−3.08±0.05 and T−5.4±0.059. These results together with existing infrared results show that τ2 is nearly proportional to T−0.5 and the ratio τ2/τ3 is 0.91 at 296 K. An initial measurement is reported for collision induced absorption in H2. The results for all three gases have been compared to previously reported results in the low frequency region.

High sensitivity and high Q-factor nanoslotted parallel quadrabeam photonic crystal cavity for real-time and label-free sensing

2014 ◽  
Vol 105 (6) ◽  
pp. 063118 ◽  
Author(s):  
Daquan Yang ◽  
Shota Kita ◽  
Feng Liang ◽  
Cheng Wang ◽  
Huiping Tian ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Real Time ◽  
High Sensitivity ◽  
Q Factor ◽  
Label Free ◽  
Photonic Crystal Cavity ◽  
High Q

Design and Simulation of Capacitive Micromechaned Gyroscope

2011 ◽  
Vol 211-212 ◽  
pp. 909-913
Author(s):  
Yun Bo Shi ◽  
Xing Juan Zhao ◽  
Jun Tang ◽  
Jun Liu ◽  
Rui Rong Wang
Keyword(s):  
Atmospheric Pressure ◽  
Simulation Analysis ◽  
High Sensitivity ◽  
Drive Mode ◽  
Close Match ◽  
High Q ◽  
Air Damping ◽  
Large Numbers ◽  
Detection Mode ◽  
Micromachined Gyroscope

By researching and investigating the structure of capacitive gyroscopes, A novel capacitive micromachined gyroscope is proposed and the structure is designed. The method of electrostatic comber drive, capacitive detection of bar structure is used for the structure, and these make the gyroscope high sensitivity. The main air damping of the drive mode and detection mode is slide film damping, it is possible to make the gyroscope achieve high Q-values at atmospheric pressure. The decoupled gyroscope is designed, too. By large numbers of simulation analysis， frequencies of the first six steps mode are gained, nature frequencies of drive mode and sense mode of gyroscope are a close match, and rationality of the structure is validated. At last, the structure encapsulated is presented.

Time Domain Zero Field NMR and NQR

1986 ◽  
Vol 41 (1-2) ◽  
pp. 440-444 ◽  
Author(s):  
A. Bielecki ◽  
D. B. Zax ◽  
A. M. Thayer ◽  
J. M. Millar ◽  
A. Pines
Keyword(s):  
Time Domain ◽  
Relaxation Times ◽  
Low Frequency ◽  
High Sensitivity ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Zero Field ◽  
Spin Lattice ◽  
Field Cycling ◽  
The Time Domain

Field cycling methods are described for the time domain measurement of nuclear quadrupolar and dipolar spectra in zero applied field. Since these techniques do not involve irradiation in zero field, they offer significant advantages in terms of resolution, sensitivity at low frequency, and the accessible range of spin lattice relaxation times. Sample data are shown which illustrate the high sensitivity and resolution attainable. Comparison is made to other field cycling methods, and an outline of basic instrumental requirements is given.

Silicon on-chip side-coupled high-Q micro-cavities for the multiplexing of high sensitivity photonic crystal integrated sensors array

2016 ◽  
Vol 374 ◽  
pp. 1-7 ◽  
Author(s):  
Daquan Yang ◽  
Chunhong Wang ◽  
Wei Yuan ◽  
Bo Wang ◽  
Yujie Yang ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
High Sensitivity ◽  
Integrated Sensors ◽  
High Q ◽  
Sensors Array ◽  
On Chip

Collision-induced absorption in ethane–rare gas mixtures

1983 ◽  
Vol 61 (4) ◽  
pp. 633-640 ◽  
Author(s):  
I. R. Dagg ◽  
L. A. A. Read ◽  
A. Anderson
Keyword(s):  
Fourier Transform ◽  
Temperature Dependence ◽  
Quadrupole Moment ◽  
Gas Mixtures ◽  
Rare Gas ◽  
Fourier Transform Spectrometer ◽  
Rare Gases ◽  
Induced Absorption ◽  
Absolute Value ◽  
The Absolute

The collision-induced spectra of mixtures of ethane and each of the rare gases He, Ar, Kr, and Xe in the 40–360 cm−1 region have been obtained using a Michelson Fourier transform spectrometer. In addition, the temperature dependence of the absorption in ethane and ethane–xenon mixtures is reported. All results have been analyzed according to the theory for quadrupole induced rotation–translation absorption. The absolute value of the quadrupole moment of ethane is estimated to be less than 1.0 B and most likely less than 0.5 B. Various speculations are made concerning the induction mechanisms (other than quadrupolar) for each of the mixtures.

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