Time domain noise measurements of the media on aliminum and glass substrates

Author(s):  
H. Kataoka ◽  
E. Fujita ◽  
D.D. Djayaprawira ◽  
Y. Matsuda
1970 ◽  
Author(s):  
J Burke ◽  
W Moore ◽  
R Rydin ◽  
K Seemann

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000117-000122
Author(s):  
Soshu Kirihara ◽  
Yousuke Itakura ◽  
Satoko Tasaki

Titania micro patterns with periodic arrangements were formed on glass substrates successfully for electromagnetic wave energy resonations and localizations in terahertz frequency ranges. Geometric arrangements of acryl polygon tablets with titania particles dispersions by using micro patterning stereolithography. Moreover, periodically arranged full titania tablets with anatase phase were created homogeneously though liquid phase crystal depositions of water solvent processes under micro templates fabricated by using the stereolithography system. The terahertz wave properties were measured and simulated by a using time domain spectroscopic system and finite difference time domain method. The terahertz waves having micrometer order wavelengths and belonging in far-infrared frequency ranges are expected to apply for various types of novel sensors which can detect micro cracks on materials surfaces, micro defects in electric devices, bacteria in foods, and cancer cells in human skins.


2021 ◽  
Vol 11 (5) ◽  
pp. 2281
Author(s):  
Nana Su ◽  
Qingbang Han ◽  
Yu Yang ◽  
Minglei Shan ◽  
Jian Jiang

To study the leakage situation of a liquid-filled pipe in long-term service, a model of a liquid-filled pipe embedded in an infinite porous medium as well as in a finite porous medium is designed. The principal motivation is to perform detailed quantitative analysis of the longitudinal guided wave propagating in a liquid-filled pipe embedded in a saturated porous medium. The problems of pipeline leakage and porosity as well as the media outside the pipe are solved to identify the characteristics of the guided wave in a more practical model. The characteristics of the guided wave are investigated theoretically and numerically, with special emphasis on the influence of porous medium parameters on the dispersion properties. Assuming the pipe is a cylindrical shell buried in an isotropic, homogeneous, and porous medium, the dispersion equations are established based on the elastic-dynamic equations and the modified Biot liquid-saturated porous theory. The characteristics of dispersion, time-domain waveform and attenuation curves varying with porous medium parameters, wrapping layer material, and thickness, are all analyzed. The increase in porosity decreases the partial mode phase velocity in the liquid-filled pipe embedded in the finite porous medium. The characteristics of attenuation are in good agreement with the dispersion curves and the time-domain waveform results.


Author(s):  
Patrick E. Hopkins ◽  
Manish Mittal ◽  
Leslie M. Phinney ◽  
Anne M. Grillet ◽  
Eric M. Furst

We report on the ultra-low thermal conductivity of a series of convectively assembled, anisotropic titania (TiO2) nanoparticle films. The TiO2 films are fabricated on aluminum coated glass substrates by flow coating a suspension of ellipsoidal colloidal nanoparticles, resulting in structured films with tailored order. Time domain thermoreflectance is used to measure the thermal conductivity of the TiO2 films. The thermal conductivities of these nanoparticle films are dependent on nanoparticle orientational order and films with more randomly oriented particles exhibit thermal conductivities less than the amorphous limit.


2005 ◽  
Vol 3 ◽  
pp. 219-225 ◽  
Author(s):  
M. Rahman ◽  
R. Marklein

Abstract. This paper presents a time-domain technique to compute the electromagnetic fields and to reconstruct the permittivity profile within a one-dimensional medium of finite length. The medium is characterized by a permittivity as well as conductivity profile which vary only with depth. The discussed scattering problem is thus one-dimensional. The modeling tool is divided into two different schemes which are named as the forward solver and the inverse solver. The task of the forward solver is to compute the internal fields of the specimen which is performed by Green’s function approach. When a known electromagnetic wave is incident normally on the media, the resulting electromagnetic field within the media can be calculated by constructing a Green’s operator. This operator maps the incident field on either side of the medium to the field at an arbitrary observation point. It is nothing but a matrix of integral operators with kernels satisfying known partial differential equations. The reflection and transmission behavior of the medium is also determined from the boundary values of the Green's operator. The inverse solver is responsible for solving an inverse scattering problem by reconstructing the permittivity profile of the medium. Though it is possible to use several algorithms to solve this problem, the invariant embedding method, also known as the layer-stripping method, has been implemented here due to the advantage that it requires a finite time trace of reflection data. Here only one round trip of reflection data is used, where one round trip is defined by the time required by the pulse to propagate through the medium and back again. The inversion process begins by retrieving the reflection kernel from the reflected wave data by simply using a deconvolution technique. The rest of the task can easily be performed by applying a numerical approach to determine different profile parameters. Both the solvers have been found to have the ability to deal with different types of slabs and incident electromagnetic pulses. Slabs having continuous and discontinuous relative permittivity have already been tested successfully. The tested electromagnetic pulses are a Dirac, Gaussian and sinusoidal pulse. Due to sampling, the resolution of the system also plays a significant role in obtaining better outputs from this scheme.


Author(s):  
Evelyn R. Ackerman ◽  
Gary D. Burnett

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.


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