Determination of the correlation spectrum of oscillators with low noise

1989 ◽  
Vol 37 (1) ◽  
pp. 90-101 ◽  
Author(s):  
F.X. Kaertner
Keyword(s):  
Low Noise ◽  
Correlation Spectrum

A Wearable Biosensor Based on Bienzyme Gel-Membrane for Sweat Lactate Monitoring by Mounting on Eyeglasses

2020 ◽  
Vol 20 (3) ◽  
pp. 1495-1503 ◽  
Author(s):  
Lili Zhang ◽  
Jian Liu ◽  
Zhenling Fu ◽  
Liguo Qi
Keyword(s):  
Physical Exercise ◽  
Low Noise ◽  
Lactate Oxidase ◽  
Electron Mediator ◽  
Enzymatic Biosensor ◽  
Current Change ◽  
Chemical Selectivity ◽  
Sweat Lactate ◽  
Change Tendency

A new enzymatic biosensor worn on eyeglasses has been developed for low-noise and noninvasive determination of lactate in human sweat during physical exercise. The Os (osmium)-complex, the electron mediator between the enzyme and the electrode, was first immobilized on a flexibly printed carbon electrode. Then, a gel membrane with the stereoscopic reticular structure of lactate oxidase and horseradish peroxidase was casted on the electrode to form the biosensor. Linearity of the biosensor was observed for up to 25 mM lactate in a phosphate buffered solution of pH 7.0. Chemical selectivity was evaluated by adding common interferent species such as ascorbic acid, glucose and uric acid to the lactate. The negligible current interference indicated excellent discriminatory selectivity of the biosensor. Applied to an analysis of the real sweat lactate dynamics of healthy subjects during cycling exercise, the amperometric profiles of the biosensors reflected changes in sweat lactate that depended on physical exercise intensity. Compared with other reported epidermal biosensors attached to the arm or leg, our biosensor not only exhibited a similar current change tendency but also rarely suffered from deformational interference due to their forehead measurement position. Such a successful application of real-time monitoring of sweat lactate means that eyeglass-bound biosensors hold considerable promise in the physical exercise and biomedical fields.

On the determination of noise parameters of low-noise transistor devices

2015 ◽  
Vol 28 (6) ◽  
pp. 684-697
Author(s):  
M. Seelmann-Eggebert ◽  
B. Aja ◽  
B. Baldischweiler ◽  
G. Moschetti ◽  
H. Massler ◽  
...  
Keyword(s):  
Low Noise ◽  
Noise Parameters

scholarly journals Opposite sense ground rotations of a pair of Cavendish balances in earthquakes

2015 ◽  
Vol 471 (2184) ◽  
pp. 20140997
Author(s):  
Alain Bourdillon ◽  
Guy Ropars ◽  
Stéphane Gaffet ◽  
Albert Le Floch
Keyword(s):  
Ground Motions ◽  
Sensor Arrays ◽  
Low Noise ◽  
Far Field ◽  
Random Response ◽  
Frequency Bandwidth ◽  
Rotational Seismology ◽  
Wide Range ◽  
Ultra Low Noise

Among the intermingled translational and rotational effects occurring in earthquakes, the translational effects are rather well understood. Recent experiments have been performed to investigate the rotational effects which have been observed for centuries that remain intriguing and less well understood. Although rotational seismology is of interest in a wide range of disciplines, rotational ground motions remain challenging to detect directly, especially their sense of rotation. To avoid a possible random response of a single balance, we locate two Cavendish balances in an ultra-low-noise laboratory. For the two successive 2012 Italian earthquakes in Emilia detected in exactly the same direction, opposed counterclockwise and clockwise responses of the two balances are recorded at the same site. Despite the complex combinations of Rayleigh and Love surface waves in the far-field, the two circular fundamental eigenmodes of the gravity-free torsion balances permit the determination of the ground rotation senses, which are indirectly confirmed by the phase shifted acceleration components in the balance frequency bandwidth, as well as the corresponding opposite driving angular impulses. The versatility of the Cavendish balances suggests that they could be used as inexpensive rotational sensor arrays in seismic areas to follow the propagation of ground rotations from the epicentres.

Acoustic Sensitivity Analysis Using the Distributed Source Energy Boundary Point Method

2011 ◽  
Vol 130-134 ◽  
pp. 76-79
Author(s):  
Li Tao Chen ◽  
Jian Chen ◽  
Bing Rong Zhang ◽  
Wu Zhang
Keyword(s):  
Boundary Point ◽  
Low Noise ◽  
Point Method ◽  
Design Parameters ◽  
Distributed Source ◽  
Boundary Point Method ◽  
Acoustic Sensitivity ◽  
Low Noise Design ◽  
Acoustical Energy

The determination of the sensitivity of the acoustical characteristics of vibrating systems with respect to the variation of the design parameters can provide a method to low-noise design of mechanical structure objectively and quantitatively. Using the Distributed source energy boundary point method, the expressions of the change of the acoustical energy density with respect to design variable is presented in this paper. The Distributed source energy boundary point method is a speedy and precise method which can avoid the complex computing of the singularity integral in EBEM. The correctness and availability is validated by the numerical simulation.

Observations of NH3 in Southern Sources

1977 ◽  
Vol 3 (2) ◽  
pp. 152-154 ◽  
Author(s):  
R. A. Batchelor ◽  
F. F. Gardner ◽  
S. H. Knowles ◽  
U. Mebold
Keyword(s):  
Hyperfine Structure ◽  
Hii Regions ◽  
Low Noise ◽  
Interstellar Molecule ◽  
Dark Clouds ◽  
Brightness Temperatures

Ammonia was the first interstellar molecule with more than two atoms to be discovered (Cheung et al. 1968). Since that time it has been observed in many HII regions and dark clouds (Mayer et al. 1973; Morris et al. 1973; Cheung et al. 1973; Kaifu et al. 1975). The molecule has a rich rotation-inversion spectrum with about 10 transitions in the range 23-25 GHz. Each line has hyperfine structure which permits, in principle, the determination of optical depths, filling factors and excitation. Unfortunately line brightness temperatures are low (<1 K) so that a low-noise receiving system and long integration times are required to exploit these possibilities.

Piston dynamics analysis considering skirt-liner dynamic clearance

2019 ◽  
Vol 233 (13) ◽  
pp. 3538-3553 ◽  
Author(s):  
Jingyi Tian ◽  
Huihua Feng ◽  
Yuanjie Feng ◽  
Zhengwei Yang ◽  
Chengjun Zhu ◽  
...  
Keyword(s):  
Simulation Model ◽  
High Frequency ◽  
Thermal Deformation ◽  
Structural Parameters ◽  
Accurate Determination ◽  
Low Noise ◽  
Dynamics Analysis ◽  
Piston Skirt ◽  
The Impact

Piston slap force is one of the main sources of mechanical engine noise. To obtain a more accurate determination of the piston slap force and minimize piston slap noise, a new simulation model that considers dynamic clearance of the piston skirt and liner has been established in this study. The skirt-liner dynamic clearance is caused mainly by the elastic deformation and thermal deformation of the piston. Comparing three different models, it was found that the impact of dynamic clearance on the piston slap force is reflected mainly in the medium-high frequency, which is the sensitive frequency of the slap noise. Therefore, it is necessary to consider dynamic clearance in the simulation model. In addition, the mechanisms behind the dynamic clearance effect on fluid lubrication, piston dynamics, and piston slap noise were observed. In particular, three typical structural parameters in piston dynamics (the piston pin offset, piston-liner clearance, and piston skirt profile) were studied. The analyses provide guidance for the design of low-noise engines.

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