Development of Helicopters Sound Detection Systems

2006 ◽  
Author(s):  
Hassan Fahmy Hashem ◽  
Abbas Amin
Keyword(s):  
Detection Systems ◽  
Sound Detection

Magnetoacoustic Tomography with Magnetic Induction (MAT-MI) Reconstruction Algorithm Based on Characteristics of Acoustic Transducer

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Ren Ma ◽  
Tao Yin ◽  
Zhipeng Liu
Keyword(s):  
Interpolation Method ◽  
Correlation Coefficients ◽  
Reconstruction Algorithm ◽  
Element Analysis ◽  
Detection Systems ◽  
Acoustic Transducers ◽  
Transient Electromagnetic ◽  
Acoustic Transducer ◽  
Sound Detection ◽  
Set Up

AbstractA MAT-MI reconstruction algorithm was applied to general sound detection systems, and the influence of acoustic transducers on MAT-MI image reconstruction was investigated in this paper. The acoustic intensity measurement system was used to measure the acoustic field, and the data was then used to build the acoustic transducer model by a interpolation method. The model was applied to forward and inverse problems of MAT-MI based on Green’s function and discretization method. In order to verify the algorithm, a simulation was carried out using sphere scan schema and cylinder scan schema. A 3D phantom model was set up based on S-L model in CT, with the help of finite element analysis method and the distribution of the transient electromagnetic field and the eddy currentwere calculated. Simulation and reconstruction results through numerical calculation using MATLAB were obtained. Results show that the algorithm can reconstruct the distribution of acoustic source vector; the correlation coefficients are 98.49% and 94.96%, and can be applied to the general transducer. This study provided a basis for the experimental study of MAT-MI and a precise reconstruction of conductivity distribution.

The Potentials of Scanning Microscopy

1968 ◽  
Vol 26 ◽  
pp. 352-353
Author(s):  
A. V. Crewe
Keyword(s):  
Salient Feature ◽  
Secondary Emission ◽  
Resolving Power ◽  
X Rays ◽  
Scanning Microscope ◽  
Forming Process ◽  
Additional Tool ◽  
Detection Systems ◽  
Conventional Microscope ◽  
Present Information

If the resolving power of a scanning electron microscope can be improved until it is comparable to that of a conventional microscope, it would serve as a valuable additional tool in many investigations.The salient feature of scanning microscopes is that the image-forming process takes place before the electrons strike the specimen. This means that several different detection systems can be employed in order to present information about the specimen. In our own particular work we have concentrated on the use of energy loss information in the beam which is transmitted through the specimen, but there are also numerous other possibilities (such as secondary emission, generation of X-rays, and cathode luminescence).Another difference between the pictures one would obtain from the scanning microscope and those obtained from a conventional microscope is that the diffraction phenomena are totally different. The only diffraction phenomena which would be seen in the scanning microscope are those which exist in the beam itself, and not those produced by the specimen.

Universal ESEM

1993 ◽  
Vol 51 ◽  
pp. 786-787
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Vacuum ◽  
Natural Extension ◽  
Necessary Condition ◽  
Environmental Scanning ◽  
Detection Systems ◽  
Small Gain ◽  
Detection Medium ◽  
Scanning Electron

The environmental scanning electron microscope (ESEM) has evolved as the natural extension of the scanning electron microscope (SEM), both historically and technologically. ESEM allows the introduction of a gaseous environment in the specimen chamber, whereas SEM operates in vacuum. One of the detection systems in ESEM, namely, the gaseous detection device (GDD) is based on the presence of gas as a detection medium. This might be interpreted as a necessary condition for the ESEM to remain operational and, hence, one might have to change instruments for operation at low or high vacuum. Initially, we may maintain the presence of a conventional secondary electron (E-T) detector in a "stand-by" position to switch on when the vacuum becomes satisfactory for its operation. However, the "rough" or "low vacuum" range of pressure may still be considered as inaccessible by both the GDD and the E-T detector, because the former has presumably very small gain and the latter still breaks down.

A microfluidic device with integrated impedance detection for λ-DNA

2003 ◽  
Vol 773 ◽  
Author(s):  
Myung-Il Park ◽  
Jonging Hong ◽  
Dae Sung Yoon ◽  
Chong-Ook Park ◽  
Geunbae Im
Keyword(s):  
Microfluidic Device ◽  
Electrochemical Impedance ◽  
Direct Detection ◽  
Full Potential ◽  
Label Free ◽  
Buffer Solution ◽  
Detection Systems ◽  
Significant Difference ◽  
Detection Of Biomolecules ◽  
Impedance Magnitude

AbstractThe large optical detection systems that are typically utilized at present may not be able to reach their full potential as portable analysis tools. Accurate, early, and fast diagnosis for many diseases requires the direct detection of biomolecules such as DNA, proteins, and cells. In this research, a glass microchip with integrated microelectrodes has been fabricated, and the performance of electrochemical impedance detection was investigated for the biomolecules. We have used label-free λ-DNA as a sample biomolecule. By changing the distance between microelectrodes, the significant difference between DW and the TE buffer solution is obtained from the impedance-frequency measurements. In addition, the comparison for the impedance magnitude of DW, the TE buffer, and λ-DNA at the same distance was analyzed.

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