A Study on the Stability of Ultra-High Frequency Vocalization of Soprano Singers

2018 ◽  
pp. 245-253
Author(s):  
Uk-Jin Song ◽  
Ik-Soo Ahn ◽  
Myung-Sook Kim ◽  
Myung-Jin Bae
Keyword(s):  
High Frequency ◽  
Ultra High Frequency ◽  
The Stability

Yagi-Uda Antenna for Navigational Aids Using HFSS

2017 ◽  
Vol 8 (3) ◽  
pp. 627
Author(s):  
Ramesh P. ◽  
V. Mathivanan
Keyword(s):  
Radiation Pattern ◽  
Frequency Band ◽  
High Frequency ◽  
Return Loss ◽  
Impedance Matching ◽  
Radiation Patterns ◽  
Ultra High Frequency ◽  
Navigational Aids ◽  
The Stability ◽  
Uhf Band

<p>In this paper, the ultra high frequency of yagi-uda antenna for navigational has been designed to improve the usable bandwidth by improving the stability of the radiation patterns. The frequency band of ultra high frequency is 300-3000 MHZ. The main aim of this paper is to reduce the loss, improve the gain and also to enhance the efficiency of ultra high frequency yagi-uda antenna for utilizing the navigational aids. The proposed UHF band of Yagi-Uda antenna has been designed by using ANSYS HFSS tool for the application of navigational aids. The characteristics specifications of yagi-uda antenna such as Radiation pattern, S11 (return loss), impedance matching and gain are analyzed in this work.</p>

A Broadband High-Gain Bi-Layer Log-Periodic Dipole Array (LPDA) for Ultra High Frequency (UHF) Conformal Load Bearing Antenna Structures (CLAS) Applications

2014 ◽  
Author(s):  
Nicholas A. Bishop ◽  
Mohammod Ali ◽  
Jason Miller ◽  
David L. Zeppettella ◽  
William Baron ◽  
...  
Keyword(s):  
High Frequency ◽  
High Gain ◽  
Load Bearing ◽  
Ultra High Frequency

Ultra-High-Frequency Pairs Trading in Gold ETFs

2017 ◽  
Author(s):  
Thong Dao ◽  
Frank McGroarty ◽  
Andrew Urquhart
Keyword(s):  
High Frequency ◽  
Pairs Trading ◽  
Ultra High Frequency

MODELING AND EXPERIMENTAL VERIFICATION OF AIR-THERMAL AND MICROWAVE-CONVECTIVE PRESOWING SEED TREATMENT

2020 ◽  
Vol 4 (41) ◽  
pp. 35-43
Author(s):  
ALEKSEY A. VASIL’EV ◽  
◽  
ALEKSEY N. VASIL’EV ◽  
DMITRIY BUDNIKOV ◽  
ANTON SHARKO
Keyword(s):  
High Frequency ◽  
Seed Treatment ◽  
Field Experiments ◽  
Research Purpose ◽  
Dense Layer ◽  
Technological Equipment ◽  
External Influence ◽  
Ultra High Frequency ◽  
Grain Processing ◽  
Seed Processing

The use of electrophysical influences for pre-sowing treatment of seeds is an effective way to increase their sowing quality. The use of these methods is limited by the fact that their implementation requires new technological equipment in grain processing lines. This problem is solved more easily when pre-sowing processing is performed using installations for active ventilation and grain drying. (Research purpose) The research purpose is in determining the possibility of using active ventilation units and ultra-high-frequency convective grain dryers for pre-sowing grain processing and to evaluating the effectiveness of such processing using computer modeling. (Materials and methods) It is necessary to ensure the uniformity of processing with external influence the seeds placed in a dense layer. Authors carried out pre-sowing treatment of seeds on real installations. Treated seeds were sown in experimental plots and the results of treatment were evaluated. (Results and discussion) The article presents graphs of changes in grain temperature and humidity during processing. To check the feasibility of pre-sowing treatment, authors performed modeling of air-heat and ultra-high-frequency convective seed treatment processes. Based on the results of field experiments, air-heat treatment stimulates the development of secondary plant roots, contributes to an intensive increase in the green mass of plants; ultra-high-frequency convective seed treatment allows increasing the number of productive stems in plants, the number of ears in one plant. (Conclusions) Technological equipment designed for drying and active ventilation of grain can be effectively used for pre-sowing seed processing. In the course of field experiments, it was revealed the possibility of controlling the structure of the crop using different types of external influence on seeds during their pre-sowing processing.

scholarly journals Ultra high frequency ultrasonography to distinguish ganglionic from aganglionic bowel wall in Hirschsprung disease: A first report

2021 ◽  
Author(s):  
Christina Granéli ◽  
Tobias Erlöv ◽  
Rodrigo Munoz Mitev ◽  
Ioanna Kasselaki ◽  
Kristine Hagelsteen ◽  
...  
Keyword(s):  
High Frequency ◽  
Bowel Wall ◽  
Hirschsprung Disease ◽  
First Report ◽  
Ultra High Frequency ◽  
High Frequency Ultrasonography

scholarly journals Delay compensation based controller for rotary electrohydraulic servo system

2021 ◽  
Author(s):  
Zakarya Omar ◽  
Xingsong Wang ◽  
Khalid Hussain ◽  
Mingxing Yang
Keyword(s):  
High Frequency ◽  
Dead Time ◽  
Sliding Mode ◽  
Servo System ◽  
Smith Predictor ◽  
Delay Compensation ◽  
Mechanical Parts ◽  
System Output ◽  
Electrohydraulic Servo System ◽  
The Stability

AbstractThe typical power-assisted hip exoskeleton utilizes rotary electrohydraulic actuator to carry out strength augmentation required by many tasks such as running, lifting loads and climbing up. Nevertheless, it is difficult to precisely control it due to the inherent nonlinearity and the large dead time occurring in the output. The presence of large dead time fires undesired fluctuation in the system output. Furthermore, the risk of damaging the mechanical parts of the actuator increases as these high-frequency underdamped oscillations surpass the natural frequency of the system. In addition, system closed-loop performance is degraded and the stability of the system is unenviably affected. In this work, a Sliding Mode Controller enhanced by a Smith predictor (SMC-SP) scheme that counts for the output delay and the inherent parameter nonlinearities is presented. SMC is utilized for its robustness against the uncertainty and nonlinearity of the servo system parameters whereas the Smith predictor alleviates the dead time of the system’s states. Experimental results show smoother response of the proposed scheme regardless of the amount of the existing dead time. The response trajectories of the proposed SMC-SP versus other control methods were compared for a different predefined dead time.

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