Добірка наукової літератури з теми "High frequency resonance method"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "High frequency resonance method".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Статті в журналах з теми "High frequency resonance method"
1
Mühlhaus, V., and Y. Kanh. "Contactless resistivity measurement with the high‐frequency series resonance method." Review of Scientific Instruments 62, no. 10 (October 1991): 2465–68. http://dx.doi.org/10.1063/1.1142265.
Повний текст джерела
2
Ding, Yong, Tiesheng Wang, Xinyu Zhang, Yuxi Zhang, and Yifei Miao. "PCCPS-PWM based vehicle-network high frequency resonance suppression method." Journal of Physics: Conference Series 1754, no. 1 (February 1, 2021): 012107. http://dx.doi.org/10.1088/1742-6596/1754/1/012107.
Повний текст джерела
3
HEIN, STEFAN, THORSTEN HOHAGE, WERNER KOCH, and JOACHIM SCHÖBERL. "Acoustic resonances in a high-lift configuration." Journal of Fluid Mechanics 582 (June 14, 2007): 179–202. http://dx.doi.org/10.1017/s0022112007005770.
Повний текст джерелаАнотація:
Low- and high-frequency acoustic resonances are computed numerically via a high-order finite-element code for a generic two-dimensional high-lift configuration with a leading-edge slat. Zero mean flow is assumed, approximating the low-Mach-number situation at aircraft landing and approach. To avoid unphysical reflections at the boundaries of the truncated computational domain, perfectly matched layer absorbing boundary conditions are implemented in the form of the complex scaling method of atomic and molecular physics. It is shown that two types of resonance exist: resonances of surface waves which scale with the total airfoil length and longitudinal cavity-type resonances which scale with the slat cove length. Minima exist in the temporal decay rate which can be associated with the slat cove resonances and depend on the slat cove geometry. All resonances are damped owing to radiation losses. However, if coherent noise sources exist, as observed in low-Reynolds-number experiments, these sources can be enhanced acoustically by the above resonances if the source frequency is close to a resonant frequency.
4
Xiong, Wei, Liyang Ou, Xuezhou Chen, and Chaobo Li. "Electrical Characterization Method for Resonance Performance of Photo-Elastic Modulators." Optics 2, no. 4 (December 3, 2021): 276–83. http://dx.doi.org/10.3390/opt2040026.
Повний текст джерелаАнотація:
As a kind of resonant device, the modulation efficiency of the photo-elastic modulator (PEM) is determined by its inherent resonance characteristics, including the resonance frequency and quality factor (Q-factor). The existing methods used to characterize the resonance performance of the PEM are mainly based on the optical method to measure the vibration parameters, but these methods are more complex, have a high cost, and are not able to accurately measure the quality factor. Therefore, this paper proposes an electrical characterization method based on impedance measurement. In this method, an equivalent circuit model for the PEM is established. By measuring the impedance vs. frequency curve of the PEM and using the equivalent circuit model for fitting analysis, we can obtain the parameters of the equivalent circuit model. With these parameters, we can eventually calculate the natural resonance frequency and quality factor. The above method was applied to some commercial PEM products for experimental verification. The experimental results show that this method can accurately measure the natural resonance frequency and quality factor of the PEM, and the error is less than 0.03%.
5
Cao, Wu, Kangli Liu, Haotian Kang, Shunyu Wang, Dongchen Fan, and Jianfeng Zhao. "Resonance Detection Strategy for Multi-Parallel Inverter-Based Grid-Connected Renewable Power System Using Cascaded SOGI-FLL." Sustainability 11, no. 18 (September 4, 2019): 4839. http://dx.doi.org/10.3390/su11184839.
Повний текст джерелаАнотація:
The increasing use of multi-parallel grid-connected inverters introduces both high-quality and high-capacity power, while it tends to cause a resonance instability problem. A resonance damper can virtualize a resistor at resonant frequency to suppress the instability effectively, but the resonant frequency should be detected primarily. However, the resonant current or voltage is severely distorted and oscillating, which will lead to the resonant frequency extraction being more difficult. To address it, this paper proposes a resonance detection strategy based on the cascaded second-order generalized integrators (SOGI) and the normalized frequency locked loop (FLL). The cascaded structure ensures the accuracy by completely filtering the fundamental component from the detected voltage or current, and the normalization accelerates the frequency detection. The proposed method can be used as a crucial unit of the resonance damping controller. Finally, the performance of the proposed method is verified by the MATLAB-based simulation and Hardware-in-the-Loop (HIL)-based emulation results.
6
Kirievskiy, Vladimir V., and Evgeny V. Kirievskiy. "Measuring of plasma’s velocity in electrodynamic railgun using high-frequency method." MATEC Web of Conferences 226 (2018): 04004. http://dx.doi.org/10.1051/matecconf/201822604004.
Повний текст джерелаАнотація:
A method is proposed for measuring the velocity of a moving plasma in an electrodynamic railgun in the part of internal ballistics. The achieved result is to provide a measurement of instantaneous velocity and an increase of the safety level for operation of measuring devices. The method is based on the excitation of the rail system of railgun high frequency electric oscillations during in due motion of plasma and creates current resonance. Then is continuously measured cyclic resonance frequency, and the instantaneous velocity of the plasma is determined by a formula, that consist of the current time, the cyclic resonance frequency, equivalent inductance of the power supply of railgun, linear inductance and rail length, and as well used as a model of measurement measure capacitance of capacitor, connected in parallel to rail of railgun grounded from one side. Application of plasma velocity measuring method is suitable for the highly-accurate control of plasma acceleration and pushed it to the railgun bodies with controlled acceleration, requiring measurement during movement of the plasma instantaneous values of velocity.
7
Shoyama, Tadayoshi, and Koji Fujimoto. "Measurement of High Frequency Viscoelastic Properties of Deformed Rubber." Key Engineering Materials 715 (September 2016): 139–46. http://dx.doi.org/10.4028/www.scientific.net/kem.715.139.
Повний текст джерелаАнотація:
Bearings of small turbo machines support high speed rotors rotating with the frequency over 1 [kHz]. Such bearings are often supported with O-rings made of soft materials like rubber to attenuate high frequency oscillations. Dynamic properties of rubber supporters have been measured experimentally for individual dimensions, but the universal prediction of dynamic properties for various frequencies is difficult not only because rubbers exhibit nonlinearity against its strain, but because O-ring supporters deform heterogeneously. For the precise prediction, it is necessary to investigate the viscoelasticity of rubber under various deformations and frequencies. Such properties can be measured by the standard shear vibration non-response method of ISO 6721-6 (JIS K 7244-6). However this is applicable only to low frequency range under 100 [Hz] because of the limitation of resonance frequency of the load cell. In this research, based on BERM (Base Excitation Resonant Mass) method, a new method was developed to measure the complex shear modulus at high frequencies up to 1 [kHz] of rubber sheets under homogeneous shear deformations. In the presented method, the force is calculated from the acceleration of the mass instead of the direct measurement by a load cell. Hence accurate measurement became possible even in the range beyond the resonance frequency of a load cell. The measured shear storage modulus G’ and shear loss modulus G” of deformed rubber were presented.
8
Coccetti, F., W. Dressel, P. Russer, L. Pierantoni, M. Farina, and T. Rozzi. "Accurate modeling of high frequency microelectromechanical systems (MEMS) switches in time- and frequency-domainc." Advances in Radio Science 1 (May 5, 2003): 135–38. http://dx.doi.org/10.5194/ars-1-135-2003.
Повний текст джерелаАнотація:
Abstract. In this contribution we present an accurate investigation of three different techniques for the modeling of complex planar circuits. The em analysis is performed by means of different electromagnetic full-wave solvers in the timedomain and in the frequency-domain. The first one is the Transmission Line Matrix (TLM) method. In the second one the TLM method is combined with the Integral Equation (IE) method. The latter is based on the Generalized Transverse Resonance Diffraction (GTRD). In order to test the methods we model different structures and compare the calculated Sparameters to measured results, with good agreement.
9
Li, Linlin, Sumeet S. Aphale, and Limin Zhu. "High-bandwidth nanopositioning via active control of system resonance." Frontiers of Mechanical Engineering 16, no. 2 (March 5, 2021): 331–39. http://dx.doi.org/10.1007/s11465-020-0619-x.
Повний текст джерелаАнотація:
AbstractTypically, the achievable positioning bandwidth for piezo-actuated nanopositioners is severely limited by the first, lightly-damped resonance. To overcome this issue, a variety of open- and closed-loop control techniques that commonly combine damping and tracking actions, have been reported in literature. However, in almost all these cases, the achievable closed-loop bandwidth is still limited by the original open-loop resonant frequency of the respective positioning axis. Shifting this resonance to a higher frequency would undoubtedly result in a wider bandwidth. However, such a shift typically entails a major mechanical redesign of the nanopositioner. The integral resonant control (IRC) has been reported earlier to demonstrate the significant performance enhancement, robustness to parameter uncertainty, guaranteed stability and design flexibility it affords. To further exploit the IRC scheme’s capabilities, this paper presents a method of actively shifting the resonant frequency of a nanopositioner’s axis, thereby delivering a wider closed-loop positioning bandwidth when controlled with the IRC scheme. The IRC damping control is augmented with a standard integral tracking controller to improve positioning accuracy. And both damping and tracking control parameters are analytically optimized to result in a Butterworth Filter mimicking pole-placement—maximally flat passband response. Experiments are conducted on a nanopositioner’s axis with an open-loop resonance at 508 Hz. It is shown that by employing the active resonance shifting, the closed-loop positioning bandwidth is increased from 73 to 576 Hz. Consequently, the root-mean-square tracking errors for a 100 Hz triangular trajectory are reduced by 93%.
10
Endo, Akito, Jun Akedo, and Shinichi Takeuchi. "Fundamental Study on High-Frequency Ultrasound Probes Fabricated by Aerosol Deposition Method and Hydrothermal Method." Key Engineering Materials 388 (September 2008): 159–62. http://dx.doi.org/10.4028/www.scientific.net/kem.388.159.
Повний текст джерелаАнотація:
The ultrasound probes utilized in this study were fabricated using lead zirconium titanate (PZT), which was deposited using two different methods—the aerosol deposition (AD) method and the hydrothermal method. The fabricated ultrasound probes had the same structure wherein an electrode and an acoustic backing block were attached to each transducer. In this study, we have compared the acoustic characteristics of a high-frequency ultrasound probe fabricated by the AD method with those of a probe fabricated using the hydrothermal method; further, we have studied and hence determined the optimal process that can be used in the fabrication of high-frequency ultrasound probes with a resonance frequency of 40 MHz. As a result, when the pickup voltage was compared, the ultrasound probes fabricated by the AD method exhibited a value 9.5 times higher than that of the probes fabricated by the hydrothermal method. Moreover, the ultrasound probes fabricated by the AD method were found to transmit pulses at resonance frequencies of 28 MHz, 45–50 MHz, and 82–88 MHz.
Дисертації з теми "High frequency resonance method"
1
Bar, Galit 1970. "High-frequency time domain electron paramagnetic resonance : methods and applications." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17826.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2004.Vita.
Includes bibliographical references.
There are numerous advantages to high frequency (high field) electron paramagnetic resonance (EPR) spectroscopy. Two of the most important are improved sensitivity and the improved resolution of field dependent interactions. In addition, there are many attractive features to time domain spectroscopy. Pulsed EPR allows for the design of experiments, which can specifically be used to study structure and dynamics of paramagnetic species and provide utmost resolution by separating interactions from each other. The combination of pulsed techniques and high frequencies is not only complimentary to continuous wave (CW) low frequency EPR but it also greatly increases the accessible information on paramagnetic species. High frequency, time domain EPR is still in its infancy. Spectrometers at W-band ([approximately] 95 GHz) are now available commercially but to date very few spectrometers operating at higher frequencies have been described. The spectrometer developed in the Francis Bitter Magnet Laboratory operates at a microwave (MW) frequency of 139.5 GHz corresponding to [approximately] 5 T magnetic field. The applications presented in this thesis illustrate the potential of high frequency, time domain EPR spectroscopy at 139.5 GHz in obtaining structural and mechanistic insights of several paramagnetic systems. Well resolved EPR spectra observed at 139.5 GHz of the stable tyrosine radical in ribonucleotide reductase (RNR) revealed the existence of a hydrogen bond in RNR from yeast, chapter 1. The bond length and orientation were determined from the nuclear frequencies of the proton, detected by orientation selective electron nuclear double resonance (ENDOR).
(cont.) The advantage of the time domain detection scheme is demonstrated in chapters 4, 5 and 6. A stimulated echo sequence is used to separate different organic radicals associated with the reduction chemistry and inhibition mechanisms of RNR. Using the dispersion in relaxation rates at high temperature ([approximately] 60 K) it is possible to filter the multi component spectrum. The assignment of new radicals is possible at high field, 5 T, due to the high resolution in g anisotropy. The findings support earlier proposals for the mechanism of nucleotide reduction and inhibition of this very important enzyme. To study photoexcited triplet molecules a light source was coupled to the high frequency spectrometer and the pulsed mode detection scheme was used to acquire EPR spectra. The new technique is demonstrated on several model systems. In addition to the basic advantages described above, high frequency EPR opens new frontiers for high spin systems, S >[or equal to] 1, with large spin-spin interaction. Because of the inverse field dependency of the zero field splitting, such systems may be totally EPR-silent at normal EPR frequencies. However their EPR spectra are accessible at high frequencies due to the reduction of linewidth. The Mn(II), S = 5/2, in superoxide dismutase (SOD) is a good example for such system.
by Galit Bar.
Ph.D.
2
Peairs, Daniel Marsden. "High Frequency Modeling and Experimental Analysis for Implementation of Impedance-based Structural Health Monitoring." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27925.
Повний текст джерелаАнотація:
A promising structural health monitoring (SHM) method for implementation on real world structures is impedance-based health monitoring. An in-service system is envisioned to include on board processing and perhaps wireless transfer of data. Ideally, a system could be produced as a slap-on or automatically installed addition to a structure. The research presented in this dissertation addresses issues that will help make such a system a reality. Although impedance-based SHM does not typically use an analytical model for basic damage identification, a model is necessary for more advanced features of SHM, such as damage prognosis, and to evaluate system parameters when installing on various structures. A model was developed based on circuit analysis of the previously proposed low-cost circuit for impedance-based SHM in combination with spectral elements. When a three-layer spectral element representing a piezoceramic bonded to a base beam is used, the model can predict the large peaks in the impedance response due to resonances of the bonded active sensor. Parallel and series connections of distributed sensor systems are investigated both experimentally and with the developed model. Additionally, the distribution of baseline damage metrics is determined to assess how the large quantities of data produced by a monitoring system can be handled statistically. A modification of the RMSD damage metric has also been proposed that is essentially the squared sum of the Z-statistic for each frequency point. Preferred excitation frequencies for macro-fiber composite (MFC) active sensors are statistically determined for a long composite boom under development for use in rigidizable inflatable space structures.Ph. D.
3
Бондаренко, И. Н., В. А. Николаенко, and А. В. Полищук. "The cavity with the Tunnel Diodes and Corbino-Electrodes for Analyze Dielectrics and Semiconductors." Thesis, Sumy State University, 2019. http://openarchive.nure.ua/handle/document/10409.
Повний текст джерелаАнотація:
. Study of nano structures is importance as bind the nanotechnology and applying. Many methods and tools use here (EPA); (NMR); AFM, X-ray so on. The high frequency (HF) resonance method at low temperature is sensitive and exact method because high quality of resonance and neglecting both the device noise and losses in matter. The “gaga – nano” conception take a place here too. The using little tunnel diodes as the generator and the detector in cavity is ideal for that aim. In this project cavity bottom is system of coaxial insulated rings (Corbino geometry) which applied as the low frequency (LF) analyzer as well as the modulator of HF field. So, we proposed HF - LF mini- analyzer for study of matter, the composition of device is given.
4
Menon, K. Rajalakshmi. "Application Of High Frequency Natural Resonances Extracted From Electromagnetic Scattering Response For Discrimination Of Radar Targets With Minor Variations." Thesis, Indian Institute of Science, 2001. http://hdl.handle.net/2005/159.
Повний текст джерелаАнотація:
Radars, as the name suggests, were traditionally used for Radio Detection and Ranging. Nevertheless, advances in high resolution electromagnetic simulations, Ultra Wide-Band sources, signal processing and computer technologies have resulted in a possible perception of radars as sensors for target discrimination. In this thesis, the feasibility of discrimination between targets even with minor variations in structure and material composition on the basis of radar echoes is effectively demonstrated.
It is well-known that the echoes from any target are affected by its natural frequencies which are dependent only on the shape and material composition of the target, and independent of the aspect angle or the incident waveform. The E-pulse technique is based on the fact that incident waveforms can be designed that uniquely annihilate the echoes from chosen regions of a target, and forms the basis of the method of discrimination proposed in this thesis.
Earlier methods reported in the literature, effectively discriminated only between different classes of targets with substantial variations in the overall dimensions of the body. Discrimination of targets of the same class with a minor structural modification or with a material coating on specific areas was rather difficult. This thesis attempts and successfully validates a method which comprehensively addresses this problem. The key idea of this method is to use the higher frequency resonances (which characterise the finer details of a target) in the E-pulse technique.
An obviously important aspect of target discrimination is therefore that of precisely estimating the natural frequencies for each target and understanding the changes in these frequencies, and their associations with the changes in structure and material composition. Current approaches to determine these frequencies are either based In the time or frequency
domains. While the latter approach comprises the computation of the roots of a related determinantal equation, in the time domain, the natural frequencies are extracted from the
response of a target to an impulse. Such a response can either be generated from actual experiments or by simulating the scattering response using Computational Electromagnetic (CEM) techniques. In this work, the impulse response is obtained from the frequency response of the scatterers in the frequency range of interest. Since no single CEM technique can effectively cover the entire range of frequencies needed for the E-Pulse synthesis. The Method of Moments and Physical Optics have been used for low and high frequency scattering respectively. The results obtained using the latter technique are validated by comparing with those obtained using Method of Moments at the transition frequencies and Geometrical Theory of Diffraction (GTD).
The natural frequencies (i.e., poles of a corresponding transfer function) are extracted from the impulse response using Prony's algorithm. One of the parameters in this method is the number of such poles (i.e.. the order of the transfer function) present in the response, and the accuracy of the computed pole values depends on this assumed order. Here, the Hankel singular values of a transfer function is used to estimate the number of poles. This in turn implies that a specific norm of the error between a transfer function corresponding to the frequency response generated earlier, and a transfer function with an assumed order obtained using Prony's method is minimised.
In the thesis, a wide range of target shapes are considered for purposes of illustration: wires, cylinders, spheres, plates and complex bodies such as aircraft, and the discrimination capability is demonstrated by introducing minor perturbations in their shape and/or material composition. .The following cases are considered here: (a) Wires: Conducting wires with a protrusion in one segment; conducting wire from another coated with a dielectric in a segment, (b) Cylinders: Conducting cylinders with one perturbed; conducting cylinders with a portion scrapped off in the middle, (c) Plates: Conducting plates with a elongation on one comer; conducting plate with another one with a hole in the centre, (d) Spheres: Conducting spheres with different radii; conducting spheres with Radar Absorbing Material coated spheres with different coating thickness; conducting spheres with chiral coated spheres with varying coating thickness, (e) Aircraft: Canonical model of MiG-29 aircraft from a similar one with stores placed under the wing.
5
Magill, Arthur W. "Ultra-high frequency magnetic resonance imaging." Thesis, University of Nottingham, 2007. http://eprints.nottingham.ac.uk/10740/.
Повний текст джерелаАнотація:
This thesis addresses the problem of radiofrequency probe design for Ultra High Frequency Magnetic Resonance Imaging (7T). The signal-to-noise ratio available in Magnetic Resonance Imaging (MRI) is determined by the static magnetic field strength, causing a continued drive toward higher fields to enable faster image acquisition at finer spatial resolution. The resonant frequency increases linearly with static field strength. At 7T the proton resonant frequency is 300MHz, with a wavelength of approximately 13cm in tissue. As this is smaller than the dimensions of the human head, the phase of the radiofrequency (RF) signal varies considerably across the sample, producing field cancellation due to interference. A full wave electromagnetic simulator, using the Transmission Line Matrix (TLM) method, was developed to investigate RF probes at high frequency. A Birdcage probe operating at 64, 128 and 300MHz (corresponding to 1.5, 3 and 7T) was simulated, loaded with an anatomically detailed human head model. A half-wave microstrip was investigated for use as a high frequency probe element. Magnetic and electric fields produced by a single microstrip were simulated, and the strip dimensions varied to investigate the effect on field penetration into the head and Specific Absorption Rate (SAR). A transmit-receive array probe using four microstrip elements was then developed. Bloch simulations were run, using TLM generated magnetic fields, to investigate imaging at short wavelength. Parallel receive probes are demonstrated to offer considerable advantage over volume probes, as signals from receive elements can be combined without interference. There is no transmit equivalent to parallel reception; simultaneous excitation of independent probe elements causes interference in exactly the same manner as a volume probe. A new imaging sequence was developed using a Burst-like encoding to allow sequential excitation of probe elements, without interference, which can be recalled in a single readout. An improvement in image homogeneity was demonstrated, and SENSE acceleration of the new imaging sequence is shown. The sequence was implemented at 3T using a purpose built four element microstrip probe. An RF multiplexer was also built to enable transmit element switching during the imaging sequence. It was demonstrated that images due to different RF excitations, acquired in a single EPI readout, can be separated.
6
Gasson, Julia. "Radio-frequency coils for high-resolution magnetic resonance imaging." Thesis, University of Exeter, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262503.
Повний текст джерела
7
Zhang, Yang 1964. "Radio frequency gradient high resolutions nuclear magnetic resonance spectroscopy." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39054.
Повний текст джерела
8
Jones, Alexa. "Radio frequency coils for ultra-high field MRI." Thesis, University of Nottingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490979.
Повний текст джерелаАнотація:
The push toward higher magnetic fields in MRI has consistently thrown up new challenges in hardware development. The recent development of a new generation of ultra-high field scanners for human imaging is no exception. The earch presented in this thesis aims to provide solutions to new technical challenges in radio-frequency probe design. All probe designs were developed for use at 7T on a Philips Acheiva full body scanner.
9
Lee, Daniel. "Radio frequency probes for ultra-high field magnetic resonance imaging." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/11889/.
Повний текст джерелаАнотація:
This thesis describes the design, construction and testing of a dome coil. The dome coil is hemispherical in shape and is intended to be used within a set of hemispherical gradient coils in a seven tesla magnetic resonance imaging magnet. The dome coil has eight independent elements and is designed to be used for parallel transmission and reception. It is shown that the dome coil produces less specific absorption rate than a conventional birdcage coil and is suitable for head imaging. A study of travelling wave magnetic resonance imaging is also presented. In this study two different methods of generating a travelling wave (using a patch antenna and an end-fire helix antenna) are compared, and the power requirements and specific absorption rate of the travelling wave approach are considered. It is concluded that travelling wave magnetic resonance imaging is best performed using a local receive coil and with the travelling wave antenna placed at least 50 cm from the subject. All theory relevant to the design, construction, testing and use of these coils and antennas is also presented.
10
Bellew, Brendan Francis. "High frequency (139.5 GHz) electron paramagnetic resonance spectroscopy of biomolecules." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38758.
Повний текст джерелаКниги з теми "High frequency resonance method"
1
FRAM, the frequency resonance analysis method: Modelling complex socio-technical systems. Farnham, Surrey, UK England: Ashgate, 2012.
Знайти повний текст джерела
2
Kunitomo, Naoto, Seisho Sato, and Daisuke Kurisu. Separating Information Maximum Likelihood Method for High-Frequency Financial Data. Tokyo: Springer Japan, 2018. http://dx.doi.org/10.1007/978-4-431-55930-6.
Повний текст джерела
3
Kaye, Rita. Words and rhymes for kids: A fun teaching tool for high frequency words and word families. Bloomington, Ind: AuthorHouse, 2009.
Знайти повний текст джерела
4
Y, Grinberg Oleg, and Berliner Lawrence J, eds. Very high frequency (VHF) ESR/EPR. New York: Kluwer Academic/Plenum Publishers, 2004.
Знайти повний текст джерела
5
High-frequency instability of the sheath-plasma resonance. Los Angeles, CA: Dept. of Physics, University of California, 1990.
Знайти повний текст джерела
6
High-frequency instability of the sheath-plasma resonance. Los Angeles, CA: Dept. of Physics, University of California, 1990.
Знайти повний текст джерела
7
(Editor), Oleg Grinberg, and Lawrence J. Berliner (Editor), eds. Very High Frequency (VHF) ESR/EPR (Biological Magnetic Resonance). Springer, 2004.
Знайти повний текст джерела
8
Giant Resonances: Fundamental High-Frequency Modes of Nuclear Excitation (Oxford Studies in Nuclear Physics). Oxford University Press, USA, 2001.
Знайти повний текст джерела
9
Kunitomo, Naoto, Seisho Sato, and Daisuke Kurisu. Separating Information Maximum Likelihood Method for High-Frequency Financial Data. Springer, 2018.
Знайти повний текст джерела
10
Torgerson,, Paul R., C. N. L. Macpherson, and D. A. Vuitton. Cystic echinococcosis. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780198570028.003.0060.
Повний текст джерелаАнотація:
Cystic echinococcosis (CE)\cystic hydatid disease is one of the most widespread and important global helminth zoonoses. The parasite Echinococcus granulosus is maintained in a wide spectrum of intermediate hosts, including sheep, goats, camels, cattle, pigs and equines. A number of wild intermediate hosts occur, including cervids in the northern part of the North American continent and Eurasia, marsupials in Australia and wild herbivores in East and southern Africa. The application of a range of molecular techniques to the characterization of the parasite has confirmed the existence of mostly host-adapted strains and genotypes of the parasite and several new species have been proposed. The ubiquitous domestic dog serves as the most important definitive host for the transmission of the parasite throughout its wide geographical range.A wide range of diagnostic techniques, including necropsy, arecoline purgation, coproantigen ELISA and DNA based tests are available for detecting E. granulosus infection in the definitive host. In intermediate animal hosts, diagnosis at post mortem still remains the most reliable option. In humans, imaging techniques including ultrasound, nuclear magnetic resonance (NMR) or computer aided tomography (CAT-scan provide not only a method of diagnosis but also reveal important clinical information on the location, condition, number and size of the hydatid cysts in man. Of these ultrasound is the most widely used diagnostic technique and is the only imaging technique for screening of populations in rural areas, where the disease is most common. A classification system has been developed which can be used to assess the likely development of a cyst and hence guide the clinician in treatment options for the patient. Treatment relies on surgery and/or percutaneous interventions, especially ‘Puncture, Aspiration, Injection, Re-aspiration’ (PAIR) and/or antiparasitic treatment with albendazole (and alternatively mebendazole).CE is largely a preventable disease. Successful elimination programmes have focused on frequent periodic treatments of dogs with anthelmintics and the control of slaughter of domestic livestock. In many regions elimination or even control remains a problem as the parasite is endemic over vast areas of low income countries where there may be limited resources for control. In some areas, such as former communist administered countries, the parasite is resurgent. New tools are becoming available to control the parasite, including a highly effective vaccine in sheep which prevents the infection in sheep and breaks the transmission cycle. In addition cost effective methods are being developed which may be appropriate in low income countries where financial resources are not available for intensive control programmes that have been successful in high income countries.
Частини книг з теми "High frequency resonance method"
1
Sojka, Antonín, Matúš Šedivý, Oleksii Laguta, Andriy Marko, Vinicius T. Santana, and Petr Neugebauer. "High-frequency EPR: current state and perspectives." In Electron Paramagnetic Resonance, 214–52. Cambridge: Royal Society of Chemistry, 2020. http://dx.doi.org/10.1039/9781839162534-00214.
Повний текст джерела
2
Cardoso, José Roberto. "Finite Element Method for High Frequency." In Electromagnetics Through the Finite Element Method, 159–72. Boca Raton : Taylor & Francis, 2016. | “A CRC title.”: CRC Press, 2016. http://dx.doi.org/10.1201/9781315366777-7.
Повний текст джерела
3
Lang, Barbara, Angelika Bunse-Gerstner, Henning Lemanczyk, Hans Georg Brachtendorf, and Rainer Laur. "An Embedding Method for High Frequency Circuits." In Scientific Computing in Electrical Engineering, 146–53. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-642-55872-6_14.
Повний текст джерела
4
Ha, Michelle, and Vladimir K. Michaelis. "High-Frequency Dynamic Nuclear Polarization NMR for Solids: Part 1 – An Introduction." In Modern Magnetic Resonance, 1–24. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-28275-6_140-1.
Повний текст джерела
5
Ha, Michelle, and Vladimir K. Michaelis. "High-Frequency Dynamic Nuclear Polarization NMR for Solids: Part 1 – An Introduction." In Modern Magnetic Resonance, 1183–206. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-28388-3_140.
Повний текст джерела
6
Ha, Michelle, and Vladimir K. Michaelis. "High-Frequency Dynamic Nuclear Polarization NMR for Solids: Part 2 – Development and Applications." In Modern Magnetic Resonance, 1–18. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-28275-6_141-1.
Повний текст джерела
7
Ha, Michelle, and Vladimir K. Michaelis. "High-Frequency Dynamic Nuclear Polarization NMR for Solids: Part 2 – Development and Applications." In Modern Magnetic Resonance, 1207–24. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-28388-3_141.
Повний текст джерела
8
Lebedev, Ya S. "High Frequency ESR: From Spectral to Spatial Resolution." In 25th Congress Ampere on Magnetic Resonance and Related Phenomena, 508–9. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-76072-3_265.
Повний текст джерела
9
Lacidogna, G., B. Montrucchio, O. Borla, and A. Carpinteri. "High-Frequency Resonance Phenomena in Materials Subjected to Mechanical Stress." In Fracture, Fatigue, Failure, and Damage Evolution, Volume 5, 211–20. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06977-7_28.
Повний текст джерела
10
López, Erick, Héctor Allende, and Héctor Allende-Cid. "A Machine Learning Method for High-Frequency Data Forecasting." In Advanced Information Systems Engineering, 621–28. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-319-12568-8_76.
Повний текст джерелаТези доповідей конференцій з теми "High frequency resonance method"
1
Zhang, Xueyan, Shenggang Yang, and Xiaoli Li. "Wind turbine bearing condition monitoring based on high frequency resonance method." In 2011 International Conference on Electronics, Communications and Control (ICECC). IEEE, 2011. http://dx.doi.org/10.1109/icecc.2011.6066289.
Повний текст джерела
2
Yuan, Yubo, Heng Nian, Bo Pang, Liang Chen, and Xiaodong Yuan. "High Frequency Resonance Damping Method based on H∞ Controller for DFIG System." In 2020 IEEE 9th International Power Electronics and Motion Control Conference (IPEMC2020-ECCE Asia). IEEE, 2020. http://dx.doi.org/10.1109/ipemc-ecceasia48364.2020.9367963.
Повний текст джерела
3
Li, Lin, and Peiyi Wang. "Evaluation of High-Order Resonance of Blade Under Wake Excitation." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-23148.
Повний текст джерелаАнотація:
Avoiding the low-order resonances of blades is one of the main design goals for a mechanical structure designer of turbo machinery. However, we have to accept that there are resonance frequencies in the operating speed range of the blade, for the following reasons: Firstly, the natural frequencies of the blade are closely spaced sometimes, it is impossible to avoid them all. Secondly, in general, the higher of the resonance frequency, the lower the energy of resonance will be. But in recent 10 years, the high-order blade resonances present more and more frequently in turbo machinery, which induce a lot of HCF problems. As the considerations above, studies on the high-order vibration of blades become necessary and important. In the cascade, the high-order vibration of blades is mainly induced by the wakes from upstream. An obvious difference of the wake excitation from the common excitations resides in its asynchronism, that is, the maximum value of aerodynamic force from wakes at each point doesn’t appear at the same time, because except the frequency, the distribution of the aerodynamic force field depends on two parameters: not only amplitude but also phase angle. Both are functions of coordinates. In this paper, the related position in Euclidean Space between the asynchronous excitation field and the modal displacement of blade were deal with to evaluate the strength of the high-order resonance of blade. The effect of the asynchronous aerodynamic force field on the blade resonance was studied either. Finally a method for evaluation of high-order resonance of blade excited by wake fluid is proposed. A numerical case was studied either, which demonstrates that the proposed evaluation on high-order resonance is practical in engineering problem.
4
Park, Hwa-Pyeong, Mina Kim, Hyunjun Choi, Jee-Hoon Jung, Sang Gyu Cheon, and Chang Ui Lee. "Synchronous Rectification Method for High Frequency CLLC Resonant Cnverter." In 2019 IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia). IEEE, 2019. http://dx.doi.org/10.1109/wipdaasia.2019.8760308.
Повний текст джерела
5
Li, Hong Bo, Thierry Kayiranga, Xinchun Lin, Yanjun Shi, and Hui Li. "A resonance suppression method for GaN-based single-phase quasi-Z-source PV inverter with high switching frequency." In 2015 IEEE Energy Conversion Congress and Exposition. IEEE, 2015. http://dx.doi.org/10.1109/ecce.2015.7310014.
Повний текст джерела
6
Uchiyama, Yuta, and Ryo Morita. "Experimental Evaluation of Resonance Frequency at Branch Section in Each Dry and Wet Steam Flow." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97820.
Повний текст джерелаАнотація:
Flow-induced acoustic resonances of piping system containing closed side-branches are sometimes encountered in power plants. In U.S. NPP, the steam dryer had been damaged by high cycle fatigue due to acoustic-induced vibration under a power uprating condition. The steam piping systems of actual power plants often have nearly saturated wet steam condition. Resonance frequency at branch section is one of important factors for evaluation and prediction of acoustic resonance. However, the resonance frequency in steam condition could not be estimated by using theoretical equation since the end correction under steam condition is not clarified. In addition, sound speed in wet steam, which is evaluated by theoretical isentropic equation, may be different from practical sound speed in wet steam. Although there are several previous studies about acoustic resonance, most of them are not steam flow but air flow. In the present study, the end correction in each dry and wet steam and sound speed of wet steam was evaluated from experimental results of dominant frequency of fluctuating pressure. As a result, method for predicting resonance frequency by using theoretical equation in each dry and wet steam condition was proposed.
7
Alexey Taratorkin, Alexey Taratorkin, Igor Taratorkin Igor Taratorkin, and Victor Derzhanskii Victor Derzhanskii. "Eliminationof parametric resonance oscillations in the high-speed tracked vehicle propulsion system." In FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2021-vdc-110.
Повний текст джерелаАнотація:
"Research and/or Engineering Questions/Objective The modern conditions for high-speed tracked vehicle exploitation are characterized by fast frequent changes in the environment. In these conditions, the level of requirements for reliability of tracked vehicle mechanisms and systems, which ensure its mobility, increases. Of particular importance is the trouble-free operation of the tracked vehicle propulsion system, which interacts with a multi-parameter environment and is subject to the highest dynamic loads. One of the elements limiting durability of the propulsionsystem is road wheel tires, durability of which is largely determined by their thermal stress. Their prolonged exposure to high temperatures during vehicle runs at maximum speed leads to an intense accumulation of irreversible structural changes (degradation) in solid rubber tires, deterioration of the elastic and strength properties of the material and thermal destruction. Tire heating occurs due to generation of heat due to internal friction during deformation process. The tire temperature value depends on driving conditions of the vehicle, a type of soil, an ambient temperature and design parameters, as well as on physical and mechanical properties of the tire materials and the caterpillartread, a heat transfer area, etc. The article discusses the interaction of the caterpillar track with various types of support base and its influence on the formation of dynamic loads in the structural elements of tracked vehicleautomotive components. The rationale is given for the need to study the interaction between the road wheel tires and the rubber-facedcaterpillar tread while moving along a hard surface, when a periodic change in the stiffness of the elastic interaction leads to parametric resonance excitation. Methodology To study the complex interaction of the road roller tire with a rubber-faced tread, the methods of nonlinear dynamic systems analysis are applied. Results On the basis of the theory of nonlinear elastic interaction, the stability areas of parametric oscillations are determined, the value of the modulation depth of the elastic interaction stiffness is substantiated, which ensures the elimination of parametric resonances. The validation results of the mathematical model under development are presented, and the technical solution options are proposed to ensure the elimination of parametric resonance. What does the paper offer that is new in the field including in comparison to other work by the authors? The scientific novelty of the methods (techniques) and technical solutions proposed in the project lies in the development of a method for stabilizing parametric oscillations in a nonlinear system based on investigatinganunderstudied phenomenon of the parametric resonant oscillationoccurrence in the propulsion system of high-speed tracked vehicles. Conclusions According to the results of the study, the elastic interaction of the road roller tire with the rubber-faced caterpillar tread was optimized, which makes it possible to reduce the likelihood of excitation of parametric resonant oscillations and high-frequency loading of the road wheels, reduce the tire temperature and increase the durability of the chassis elements. The engineering proposal makes it possible to stabilize the stiffness modulation depth parameter along the length of the track."
8
Li, Zerui, Kai Zhou, Yonglu Huanng, Guangya Zhu, and Bin Ye. "A Novel Partial Discharge Pulse Separation Method for Variable Frequency Resonant Test." In 2020 IEEE International Conference on High Voltage Engineering and Application (ICHVE). IEEE, 2020. http://dx.doi.org/10.1109/ichve49031.2020.9279589.
Повний текст джерела
9
Hashim, Hazem, and Asmarashid Ponniran. "Optimization of Wireless Power Transfer Configuration for High Efficiency Achievement." In Conference on Faculty Electric and Electronic 2020/1. Penerbit UTHM, 2020. http://dx.doi.org/10.30880/eeee.2020.01.01.010.
Повний текст джерелаАнотація:
This paper discusses the efficiency improvement of a wireless power transfer system based on parameters design optimization. The wireless power transfer system is designed to operate at higher frequencies in order to reduce the component sizing as well as power density improvement. Configuration of the wireless power transfer system, i.e., transmitter and receiver coil are designed based on proper resonance frequency. The principle of the parameters design optimization is based on the single transmitter – multiple receiver coil configuration which reduces the system complexity and magnetic resonant method implementation which amplify the energy transferred between the coils. Simulation using ANSYS Maxwell and ANSYS Simplorer software shows the system efficiency is at the peak at the resonance frequency of 13.5571 MHz with a total power of 18 W delivered at a distance of 5 mm. Furthermore, the efficiency of AC – DC converter and high frequency DC – AC converter considered for power conversions are 99.81% and 99.51% respectively. Therefore, the maximum power transfer efficiency of the considered wireless power transfer system configuration is determined through this study.
10
Hester, Sarah W., William E. Anderson, Michael Zoltowski, and Thomas W. Feldman. "High Frequency Signal Analysis Methods for Acoustic Modal Onset in a Continuously Varying Resonance Combustor." In 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2014. http://dx.doi.org/10.2514/6.2014-3773.
Повний текст джерелаЗвіти організацій з теми "High frequency resonance method"
1
Galili, Naftali, Roger P. Rohrbach, Itzhak Shmulevich, Yoram Fuchs, and Giora Zauberman. Non-Destructive Quality Sensing of High-Value Agricultural Commodities Through Response Analysis. United States Department of Agriculture, October 1994. http://dx.doi.org/10.32747/1994.7570549.bard.
Повний текст джерелаАнотація:
The objectives of this project were to develop nondestructive methods for detection of internal properties and firmness of fruits and vegetables. One method was based on a soft piezoelectric film transducer developed in the Technion, for analysis of fruit response to low-energy excitation. The second method was a dot-matrix piezoelectric transducer of North Carolina State University, developed for contact-pressure analysis of fruit during impact. Two research teams, one in Israel and the other in North Carolina, coordinated their research effort according to the specific objectives of the project, to develop and apply the two complementary methods for quality control of agricultural commodities. In Israel: An improved firmness testing system was developed and tested with tropical fruits. The new system included an instrumented fruit-bed of three flexible piezoelectric sensors and miniature electromagnetic hammers, which served as fruit support and low-energy excitation device, respectively. Resonant frequencies were detected for determination of firmness index. Two new acoustic parameters were developed for evaluation of fruit firmness and maturity: a dumping-ratio and a centeroid of the frequency response. Experiments were performed with avocado and mango fruits. The internal damping ratio, which may indicate fruit ripeness, increased monotonically with time, while resonant frequencies and firmness indices decreased with time. Fruit samples were tested daily by destructive penetration test. A fairy high correlation was found in tropical fruits between the penetration force and the new acoustic parameters; a lower correlation was found between this parameter and the conventional firmness index. Improved table-top firmness testing units, Firmalon, with data-logging system and on-line data analysis capacity have been built. The new device was used for the full-scale experiments in the next two years, ahead of the original program and BARD timetable. Close cooperation was initiated with local industry for development of both off-line and on-line sorting and quality control of more agricultural commodities. Firmalon units were produced and operated in major packaging houses in Israel, Belgium and Washington State, on mango and avocado, apples, pears, tomatoes, melons and some other fruits, to gain field experience with the new method. The accumulated experimental data from all these activities is still analyzed, to improve firmness sorting criteria and shelf-life predicting curves for the different fruits. The test program in commercial CA storage facilities in Washington State included seven apple varieties: Fuji, Braeburn, Gala, Granny Smith, Jonagold, Red Delicious, Golden Delicious, and D'Anjou pear variety. FI master-curves could be developed for the Braeburn, Gala, Granny Smith and Jonagold apples. These fruits showed a steady ripening process during the test period. Yet, more work should be conducted to reduce scattering of the data and to determine the confidence limits of the method. Nearly constant FI in Red Delicious and the fluctuations of FI in the Fuji apples should be re-examined. Three sets of experiment were performed with Flandria tomatoes. Despite the complex structure of the tomatoes, the acoustic method could be used for firmness evaluation and to follow the ripening evolution with time. Close agreement was achieved between the auction expert evaluation and that of the nondestructive acoustic test, where firmness index of 4.0 and more indicated grade-A tomatoes. More work is performed to refine the sorting algorithm and to develop a general ripening scale for automatic grading of tomatoes for the fresh fruit market. Galia melons were tested in Israel, in simulated export conditions. It was concluded that the Firmalon is capable of detecting the ripening of melons nondestructively, and sorted out the defective fruits from the export shipment. The cooperation with local industry resulted in development of automatic on-line prototype of the acoustic sensor, that may be incorporated with the export quality control system for melons. More interesting is the development of the remote firmness sensing method for sealed CA cool-rooms, where most of the full-year fruit yield in stored for off-season consumption. Hundreds of ripening monitor systems have been installed in major fruit storage facilities, and being evaluated now by the consumers. If successful, the new method may cause a major change in long-term fruit storage technology. More uses of the acoustic test method have been considered, for monitoring fruit maturity and harvest time, testing fruit samples or each individual fruit when entering the storage facilities, packaging house and auction, and in the supermarket. This approach may result in a full line of equipment for nondestructive quality control of fruits and vegetables, from the orchard or the greenhouse, through the entire sorting, grading and storage process, up to the consumer table. The developed technology offers a tool to determine the maturity of the fruits nondestructively by monitoring their acoustic response to mechanical impulse on the tree. A special device was built and preliminary tested in mango fruit. More development is needed to develop a portable, hand operated sensing method for this purpose. In North Carolina: Analysis method based on an Auto-Regressive (AR) model was developed for detecting the first resonance of fruit from their response to mechanical impulse. The algorithm included a routine that detects the first resonant frequency from as many sensors as possible. Experiments on Red Delicious apples were performed and their firmness was determined. The AR method allowed the detection of the first resonance. The method could be fast enough to be utilized in a real time sorting machine. Yet, further study is needed to look for improvement of the search algorithm of the methods. An impact contact-pressure measurement system and Neural Network (NN) identification method were developed to investigate the relationships between surface pressure distributions on selected fruits and their respective internal textural qualities. A piezoelectric dot-matrix pressure transducer was developed for the purpose of acquiring time-sampled pressure profiles during impact. The acquired data was transferred into a personal computer and accurate visualization of animated data were presented. Preliminary test with 10 apples has been performed. Measurement were made by the contact-pressure transducer in two different positions. Complementary measurements were made on the same apples by using the Firmalon and Magness Taylor (MT) testers. Three-layer neural network was designed. 2/3 of the contact-pressure data were used as training input data and corresponding MT data as training target data. The remaining data were used as NN checking data. Six samples randomly chosen from the ten measured samples and their corresponding Firmalon values were used as the NN training and target data, respectively. The remaining four samples' data were input to the NN. The NN results consistent with the Firmness Tester values. So, if more training data would be obtained, the output should be more accurate. In addition, the Firmness Tester values do not consistent with MT firmness tester values. The NN method developed in this study appears to be a useful tool to emulate the MT Firmness test results without destroying the apple samples. To get more accurate estimation of MT firmness a much larger training data set is required. When the larger sensitive area of the pressure sensor being developed in this project becomes available, the entire contact 'shape' will provide additional information and the neural network results would be more accurate. It has been shown that the impact information can be utilized in the determination of internal quality factors of fruit. Until now,
2
Wu, Ming C., and Connie Chang-Hasnain. High Speed Laser with > 100 Ghz Resonance Frequency. Fort Belvoir, VA: Defense Technical Information Center, February 2014. http://dx.doi.org/10.21236/ada627139.
Повний текст джерела
3
Engel, Bernard, Yael Edan, James Simon, Hanoch Pasternak, and Shimon Edelman. Neural Networks for Quality Sorting of Agricultural Produce. United States Department of Agriculture, July 1996. http://dx.doi.org/10.32747/1996.7613033.bard.
Повний текст джерелаАнотація:
The objectives of this project were to develop procedures and models, based on neural networks, for quality sorting of agricultural produce. Two research teams, one in Purdue University and the other in Israel, coordinated their research efforts on different aspects of each objective utilizing both melons and tomatoes as case studies. At Purdue: An expert system was developed to measure variances in human grading. Data were acquired from eight sensors: vision, two firmness sensors (destructive and nondestructive), chlorophyll from fluorescence, color sensor, electronic sniffer for odor detection, refractometer and a scale (mass). Data were analyzed and provided input for five classification models. Chlorophyll from fluorescence was found to give the best estimation for ripeness stage while the combination of machine vision and firmness from impact performed best for quality sorting. A new algorithm was developed to estimate and minimize training size for supervised classification. A new criteria was established to choose a training set such that a recurrent auto-associative memory neural network is stabilized. Moreover, this method provides for rapid and accurate updating of the classifier over growing seasons, production environments and cultivars. Different classification approaches (parametric and non-parametric) for grading were examined. Statistical methods were found to be as accurate as neural networks in grading. Classification models by voting did not enhance the classification significantly. A hybrid model that incorporated heuristic rules and either a numerical classifier or neural network was found to be superior in classification accuracy with half the required processing of solely the numerical classifier or neural network. In Israel: A multi-sensing approach utilizing non-destructive sensors was developed. Shape, color, stem identification, surface defects and bruises were measured using a color image processing system. Flavor parameters (sugar, acidity, volatiles) and ripeness were measured using a near-infrared system and an electronic sniffer. Mechanical properties were measured using three sensors: drop impact, resonance frequency and cyclic deformation. Classification algorithms for quality sorting of fruit based on multi-sensory data were developed and implemented. The algorithms included a dynamic artificial neural network, a back propagation neural network and multiple linear regression. Results indicated that classification based on multiple sensors may be applied in real-time sorting and can improve overall classification. Advanced image processing algorithms were developed for shape determination, bruise and stem identification and general color and color homogeneity. An unsupervised method was developed to extract necessary vision features. The primary advantage of the algorithms developed is their ability to learn to determine the visual quality of almost any fruit or vegetable with no need for specific modification and no a-priori knowledge. Moreover, since there is no assumption as to the type of blemish to be characterized, the algorithm is capable of distinguishing between stems and bruises. This enables sorting of fruit without knowing the fruits' orientation. A new algorithm for on-line clustering of data was developed. The algorithm's adaptability is designed to overcome some of the difficulties encountered when incrementally clustering sparse data and preserves information even with memory constraints. Large quantities of data (many images) of high dimensionality (due to multiple sensors) and new information arriving incrementally (a function of the temporal dynamics of any natural process) can now be processed. Furhermore, since the learning is done on-line, it can be implemented in real-time. The methodology developed was tested to determine external quality of tomatoes based on visual information. An improved model for color sorting which is stable and does not require recalibration for each season was developed for color determination. Excellent classification results were obtained for both color and firmness classification. Results indicted that maturity classification can be obtained using a drop-impact and a vision sensor in order to predict the storability and marketing of harvested fruits. In conclusion: We have been able to define quantitatively the critical parameters in the quality sorting and grading of both fresh market cantaloupes and tomatoes. We have been able to accomplish this using nondestructive measurements and in a manner consistent with expert human grading and in accordance with market acceptance. This research constructed and used large databases of both commodities, for comparative evaluation and optimization of expert system, statistical and/or neural network models. The models developed in this research were successfully tested, and should be applicable to a wide range of other fruits and vegetables. These findings are valuable for the development of on-line grading and sorting of agricultural produce through the incorporation of multiple measurement inputs that rapidly define quality in an automated manner, and in a manner consistent with the human graders and inspectors.
4
Varga, Gabriella A., Amichai Arieli, Lawrence D. Muller, Haim Tagari, Israel Bruckental, and Yair Aharoni. Effect of Rumen Available Protein, Amimo Acids and Carbohydrates on Microbial Protein Synthesis, Amino Acid Flow and Performance of High Yielding Cows. United States Department of Agriculture, August 1993. http://dx.doi.org/10.32747/1993.7568103.bard.
Повний текст джерелаАнотація:
The effect of rumen available protein amino acids and carbohydrates on microbial protein synthesis, amino acid flow and performance of high yielding dairy cows was studied. A significant relationship between the effective degradabilities of OM in feedstuffs and the in vivo ruminal OM degradation of diets of dairy cows was found. The in situ method enabled the prediction of ruminal nutrients degradability response to processing of energy and nitragenous supplements. The AA profile of the rumen undegradable protein was modified by the processing method. In a continuous culture study total N and postruminal AA flows, and bacterial efficiency, is maximal at rumen degradable levels of 65% of the CP. Responses to rumen degradable non carbohydrate (NSC) were linear up to at least 27% of DM. Higher CP flow in the abomasum was found for cows fed high ruminally degradable OM and low ruminally degradable CP diet. It appeared that in dairy cows diets, the ratio of rumen degradable OM to rumenally degradable CP should be at least 5:1 in order to maximize postruminal CP flow. The efficiency of microbial CP synthesis was higher for diets supplemented with 33% of rumen undegradable protein, with greater amounts of bacterial AA reaching the abomasum. Increase in ruminal carbohydrate availability by using high moisture corn increased proportions of propionate, postruminal nutrients flow, postruminal starch digestibility, ruminal availability of NSC, uptake of energy substrates by the mammory gland. These modifications resulted with improvement in the utilization of nonessential AA for milk protein synthesis, in higher milk protein yield. Higher postruminal NSC digestibility and higher efficiency of milk protein production were recorded in cows fed extruded corn. Increasing feeding frequency increased flow of N from the rumen to the blood, reduced diurnal variation in ruminal and ammonia, and of plasma urea and improved postruminal NSC and CIP digestibility and total tract digestibilities. Milk and constituent yield increased with more frequent feeding. In a study performed in a commercial dairy herd, changes in energy and nitrogenous substrates level suggested that increasing feeding frequency may improve dietary nitrogen utilization and may shift metabolism toward more glucogenesis. It was concluded that efficiency of milk protein yield in high producing cows might be improved by an optimization of ruminal and post-ruminal supplies of energy and nitrogenous substrates. Such an optimization can be achieved by processing of energy and nitrogenous feedstuffs, and by increasing feeding frequency. In situ data may provide means for elucidation of the optimal processing conditions.
5
Malej, Matt, and Fengyan Shi. Suppressing the pressure-source instability in modeling deep-draft vessels with low under-keel clearance in FUNWAVE-TVD. Engineer Research and Development Center (U.S.), May 2021. http://dx.doi.org/10.21079/11681/40639.
Повний текст джерелаАнотація:
This Coastal and Hydraulics Engineering Technical Note (CHETN) documents the development through verification and validation of three instability-suppressing mechanisms in FUNWAVE-TVD, a Boussinesq-type numerical wave model, when modeling deep-draft vessels with a low under-keel clearance (UKC). Many large commercial ports and channels (e.g., Houston Ship Channel, Galveston, US Army Corps of Engineers [USACE]) are traveled and affected by tens of thousands of commercial vessel passages per year. In a series of recent projects undertaken for the Galveston District (USACE), it was discovered that when deep-draft vessels are modeled using pressure-source mechanisms, they can suffer from model instabilities when low UKC is employed (e.g., vessel draft of 12 m¹ in a channel of 15 m or less of depth), rendering a simulation unstable and obsolete. As an increasingly large number of deep-draft vessels are put into service, this problem is becoming more severe. This presents an operational challenge when modeling large container-type vessels in busy shipping channels, as these often will come as close as 1 m to the bottom of the channel, or even touch the bottom. This behavior would subsequently exhibit a numerical discontinuity in a given model and could severely limit the sample size of modeled vessels. This CHETN outlines a robust approach to suppressing such instability without compromising the integrity of the far-field vessel wave/wake solution. The three methods developed in this study aim to suppress high-frequency spikes generated nearfield of a vessel. They are a shock-capturing method, a friction method, and a viscosity method, respectively. The tests show that the combined shock-capturing and friction method is the most effective method to suppress the local high-frequency noises, while not affecting the far-field solution. A strong test, in which the target draft is larger than the channel depth, shows that there are no high-frequency noises generated in the case of ship squat as long as the shock-capturing method is used.
6
van der Heijden, Joost. Optimizing electron temperature in quantum dot devices. QDevil ApS, March 2021. http://dx.doi.org/10.53109/ypdh3824.
Повний текст джерелаАнотація:
The performance and accuracy of quantum electronics is substantially degraded when the temperature of the electrons in the devices is too high. The electron temperature can be reduced with appropriate thermal anchoring and by filtering both the low frequency and radio frequency noise. Ultimately, for high performance filters the electron temperature can approach the phonon temperature (as measured by resistive thermometers) in a dilution refrigerator. In this application note, the method for measuring the electron temperature in a typical quantum electronics device using Coulomb blockade thermometry is described. This technique is applied to find the readily achievable electron temperature in the device when using the QFilter provided by QDevil. With our thermometry measurements, using a single GaAs/AlGaAs quantum dot in an optimized experimental setup, we determined an electron temperature of 28 ± 2 milli-Kelvin for a dilution refrigerator base temperature of 18 milli-Kelvin.
7
Xing, Lei, Hongmin Guo, and Zhiqian Wang. Efficacy and safety of Suzi Jiangqi Decoction in patients with acute exacerbation of chronic obstructive pulmonary disease A protocol for systematic review and meta analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, August 2021. http://dx.doi.org/10.37766/inplasy2021.8.0035.
Повний текст джерелаАнотація:
Background: Chronic obstructive pulmonary disease (COPD) is characterized by chronic respiratory symptoms. The respiratory symptoms of patients with acute exacerbation of COPD (AECOPD) worsen rapidly. At present, traditional western medicine treatment can not effectively alleviate the symptoms and attack frequency of patients. Suzi Jiangqi decoction(SZJQ) has a good clinical effect in the treatment of AECOPD. Due to the lack of evidence-based medicine, it can not provide an effective systematic evaluation for the treatment of AECOPD with Suzi Jiangqi decoction. Therefore, it is necessary to provide high-quality evidence evaluation for the clinical efficacy and safety of Suzi Jiangqi Decoction in the treatment of AECOPD. Methods: Two researchers independently retrieved randomized controlled trial (RCT) and quasi-RCTs of SZJQ in the treatment of AECOPD from databases including PubMed, Web of science, the Cochrane Library, CBM, CNKI, Sinomed, VIP and WanFang.The included studies were evaluated for quality according to the RCT quality assessment method provided by Cochrane Reviewer's Handbook 5.3.Review Manager 5.3 software provided by the Cochrane collaboration was used for meta-analysis. Results: This study will provide systematic review on the efficacy and safety of SZJQ as adjuvant therapy in patients with AECOPD by rigorous quality assessment and reasonable data synthesis. Conclusions: This systematic review will provide the good evidence currently on SZJQ as adjuvant therapy in patients with AECOPD.
8
Ahmad, Noshin S., Raul Pineda-Mendez, Fahad Alqahtani, Mario Romero, Jose Thomaz, and Andrew P. Tarko. Effective Design and Operation of Pedestrian Crossings. Purdue University, 2022. http://dx.doi.org/10.5703/1288284317438.
Повний текст джерелаАнотація:
Pedestrians are vulnerable road users since they are prone to more severe injuries in any vehicular collision. While innovative solutions promise improved pedestrian safety, a careful analysis of local conditions is required before selecting proper corrective measures. This research study had two focuses: (1) methodology to identify roads and areas in Indiana where the frequency and severity of pedestrian collisions are heightened above the acceptable level, and (2) selecting effective countermeasures to mitigate or eliminate safety-critical conditions. Two general methods of identifying specific pedestrian safety concerns were proposed: (1) area-wide analysis, and (2) road-focused analysis. A suitable tool, Safety Needs Analysis Program (SNAP), is currently under development by the research team and is likely the future method to implement an area-wide type of analysis. The following models have been developed to facilitate the road-focused analysis: (1) pedestrian crossing activity level to fill the gap in pedestrian traffic data, and (2) crash probability and severity models to estimate the risk of pedestrian crashes around urban intersections in Indiana. The pedestrian safety model was effectively utilized in screening and identifying high-risk urban intersection segments for safety audits and improvements. In addition, detailed guidance was provided for many potential pedestrian safety countermeasures with specific behavioral and road conditions that justify these countermeasures. Furthermore, a procedure was presented to predict the economic feasibility of the countermeasures based on crash reduction factors. The findings of this study should help expand the existing RoadHAT tool used by the Indiana Department of Transportation (INDOT) to emphasize and strengthen pedestrian safety considerations in the current tool.
9
Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion, and Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, October 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
Повний текст джерелаАнотація:
Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.
10
Vehicle Surge Reduction Technology during Towing in Parallel HEV Pickup Truck. SAE International, March 2022. http://dx.doi.org/10.4271/2022-01-0613.
Повний текст джерелаАнотація:
This paper proposes a technology to reduce vehicle surge during towing that utilizes motors and shifting to help ensure comfort in a parallel HEV pickup truck. Hybridization is one way to reduce fuel consumption and help realize carbon neutrality. Parallel HEVs have advantages in the towing, hauling, and high-load operations often carried out by pickup trucks, compared to other HEV systems. Since the engine, motor, torque converter, and transmission are connected in series in a parallel HEV, vehicle surge may occur when the lockup clutch is engaged to enhance fuel efficiency, similar to conventional powertrains. Vehicle surge is a low-frequency vibration phenomenon. In general, the source is torque fluctuation caused by the engine and tires, with amplification provided by first-order torsional driveline resonance, power plant resonance, suspension resonance, and cabin resonance. This vibration is amplified more during towing. Therefore, this paper proposes two surge reduction technologies to help achieve fuel efficiency and surge at the same time during towing. One technology is a gear shift control that avoids engine operating zones where two or more resonance frequencies coincide, which is realized by changing the equivalent inertia via appropriate gear selection. The second technology is an anti-vibration control, which makes effective use of the hybrid system motors by adding motor torque to suppress the relative displacement between the driveline and the tires.