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Study on the impedance characteristics of a high-capacity pulse tube cryocooler
Energy Reports, 2022 Stirling-type pulse tube cryocoolers are used in many applications such as military facilities, aerospace devices and superconductive systems. A major problem in improving its energy conversion efficiency is how to achieve a better impedance matching. In
Xiaokuan You +4 more
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Longitudinal impedance of two-layer tube [PDF]
Physical Review Special Topics. Accelerators and Beams, 2004 The exact analytical expression for the longitudinal impedance of two-layer cylindrical tube with finite wall thickness is obtained. The numerical results for the copper-NEG, stainless steel-copper, and ceramic-copper laminated vacuum chamber impedances ...
M. Ivanyan, V. Tsakanov
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Multilayer tube impedance and external radiation [PDF]
Physical Review Special Topics. Accelerators and Beams, 2008 The paper describes a method for calculating the longitudinal and transverse impedances of the laminated round pipe with many layers of different materials. The charge is moving along the pipe axis with arbitrary constant velocity.
M. Ivanyan +5 more
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Bayesian estimations of dissipation, sound speed, and microphone positions in impedance tubes [PDF]
JASA Express Letters, 2022 Sound speed, microphone positions, and tube wall dissipation are critical parameters for absorption and impedance measurements using the transfer-function method in an impedance tube. This work applies a Bayesian method, based on a reflection coefficient
Ziqi Chen +2 more
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An improved water-filled impedance tube [PDF]
The Journal of the Acoustical Society of America, 2003 A water-filled impedance tube capable of improved measurement accuracy and precision is reported. The measurement instrument employs a variation of the standardized two-sensor transfer function technique. Performance improvements were achieved through minimization of elastic waveguide effects and through the use of sound-hard wall-mounted acoustic ...
Wilson, PS, Roy, RA, Carey, WM
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Acoustics, 2023 A comparison is considered of the experimentally obtained impedance of locally reacting acoustic liner samples with the impedance calculated using semi-empirical Goodrich, Sobolev and Eversman models. The semi-empirical impedance models are outlined.
Vadim Palchikovskiy +3 more
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P137 Reflections Revisited: Reinterpretation Required
Artery Research, 2020 Introduction: Pressure waveshape derived parameters such as the augmentation index are related to unfavourable cardiovascular events [1]. Wave reflections determine wave shape [2], however, several findings seem to contradict the current views.
Berend Westerhof, Nico Westerhof
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An assessment of the performance of impedance tube method [PDF]
Noise Control Engineering Journal, 2014 The impedance tube method is widely used for measuring sound absorption (or reflection) coefficients of acoustic materials as a function of frequency. However, the sound absorption coefficients obtained using the impedance tube method may have some variations due to the dimensions (limits) of an impedance tube, sample preparation and sample mounting ...
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Materials Research Letters, 2022 We developed a sound absorber using a magnetorheological fluid(MR-F) based on the density and alignment angle of carbonyl iron powder(CIP) chains by the controlling the magnetic field strength and direction.
Hao Cheng +3 more
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Impedance of a rectangular beam tube with small corrugations [PDF]
Physical Review Special Topics - Accelerators and Beams, 2003 We consider the impedance of a structure with rectangular, periodic corrugations on two opposing sides of a rectangular beam tube. Using the method of field matching, we find the modes in such a structure. We then limit ourselves to the the case of small corrugations, but where the depth of corrugation is not small compared to the period.
K. L. F. Bane, G. Stupakov
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