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Jae-Gap Suh,Wan-Ho Cho,Triantafillos Koukoulas,Hack-Yoon Kim,Zhenglie Cui,Yôiti Suzuki 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.7
A laser pistonphone system capable of measuring the sensitivity modulus and phase of microphones is proposed. For the primary vibration calibration, the sine-approximation method has been applied which is used to calculate the complex sensitivity of accelerometers. This method is based on a laser interferometer with quadrature output instead of the fringe-counting method that is used in conventional laser pistonphones. Here, the laser pistonphone system based on the sine-approximation method with the quadrature signal is proposed and the measured results are compared to those obtained by the reciprocity method. The measured sensitivity with the proposed method agrees well with the result of the reciprocity method for the infrasound range. However, in case of the phase sensitivity, the discrepancy is relatively high in comparison to the sensitivity modulus. The results show that the proposed system is capable of calibrating the complex sensitivity of microphones. The improvement of the uncertainty and extension of the frequency range can be achieved by modification of the excitation system for obtaining the required stable excitation with long stroke.
Sensitivity measurement of a laboratory standard microphone by measuring the diaphragm vibration
Suh, Jae-Gap,Cho, Wan-Ho,Kim, Hack-Yoon,Cui, Zhenglie,Suzuki, Yô,iti Elsevier 2019 Applied acoustics Vol.143 No.-
<P><B>Abstract</B></P> <P>As a method to determine the sensitivity of a laboratory standard microphone, the reciprocity method is employed as an international standard (IEC61094-2). This method is highly reliable and achieves high precision. However, three microphones are essentially required for this method. This procedure is complicated and takes a long time due to many combinations of microphone pairs and couplers. To overcome these difficulties, a novel method based on the measurement of vibration on the surface of a microphone using a laser Doppler vibrometer is proposed. It aims to obtain the sensitivity of a laboratory standard microphone. To this end, the relationship between the surface velocity of the diaphragm centre and acoustic volume velocity induced by the vibration of the diaphragm surface is investigated, and an empirical model is developed by measuring the distribution of the surface velocity. This paper used an empirical model of a 1-in. laboratory standard microphone estimated with 6 samples. The estimated sensitivity using this model has a difference of about 0.1 dB from the results of the reciprocity method applied to samples not used for estimating the empirical model.</P>
Apoptosis induced in vivo by new type gosling viral enteritis virus
Shun Chen,Anchun Cheng,Mingshu Wang,Dekang Zhu,Renyong Jia,Qihui Luo,Hengmin Cui,Yi Zhou,Yin Wang,Zhiwen Xu,Zhengli Chen,Xiaoyue Chen,Xiaoyu Wang 대한수의학회 2011 JOURNAL OF VETERINARY SCIENCE Vol.12 No.4
In this study, apoptosis was induced by new type gosling viral enteritis virus (NGVEV) in experimentally infected goslings is reported in detail for the first time. After 3-day-old goslings were orally inoculated with a NGVEV-CN strain suspension, the time course of NGVEV effects on apoptotic morphological changes of the internal tissues was evaluated. These changes were observed by histological analysis with light microscopy and ultrastructural analysis with transmission electron microscopy. DNA fragmentation was assessed with a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and DNA ladder analysis. A series of characteristic apoptotic morphological changes including chromatin condensation and margination, cytoplasmic shrinkage, plasma membrane blebbing, and formation of apoptotic bodies were noted. Apoptosis was readily observed in the lymphoid and gastrointestinal organs, and sporadically occurred in other organs after 3 days post-infection (PI). The presence and quantity of TUNEL-positive cells increased with infection time until 9 days PI. DNA extracted from the NGVEV-infected gosling cells displayed characteristic 180~200 bp ladders. Apoptotic cells were ubiquitously distributed, especially among lymphocytes, macrophages, monocytes, and epithelial and intestinal cells. Necrosis was subsequently detected during the late NGVEV-infection phase, which was characterized by cell swelling, plasma membrane collapse, and rapidly lysis. Our results suggested that apoptosis may play an important role in the pathogenesis of NGVE disease.