Papers by Author: Wen Dong Zhang

Abstract: A novel MEMS vector hydrophone with bionics structure was introduced in 2007. As the acoustic-electric transducer infrastructure has been optimized, the performance of the hydrophone has been greatly improved compared with the previous. This hydrophone calibration was finished in National Defense Underwater Acoustics Calibration Laboratory of China. According to test results, the sensitivity of the hydrophone is -165dB（including pre-amplification 20 dB）,The frequency response ranges from 20Hz to 2kHz (±5dB). And this hydrophone has a good directional pattern in form of "8"-shape.

Abstract: (Pb,La)(Zr,Ti)O₃ antiferroelectric thick films were prepared on Pt (111)/ Ti/SiO₂/Si (100) substrates by a sol-gel process. The effects of single annealing and multistep annealing on the structures and electric properties of the films were investigated. The crystal orientation and structure of the antiferroelectric thick films were studied. The thick films by multistep annealing have higher (100)-preferred orientation than them by single annealing. The surface of the films was more smooth, compact and uniform by single annealing. The antiferroelectric nature of the (Pb,La)(Zr,Ti)O₃ antiferroelectric thick films by various sintering procedures was demonstrated by P(polarization)-E(electric field) and C(capactitance)-E(electric field). The temperature dependent of the dielectric constant and loss was measured under the frequency 1, 10, and 100 kHz and comparing with traditional signal annealing, the films have phase transition from antiferroelectric state to paraelectric state by multistep annealing.

Abstract: A novel MEMS vector hydrophone with bionics structure was introduced in 2007. As the acoustic-electric transducer infrastructure and the acoustic package of hydrophone have been optimized, the performance of the hydrophone has been greatly improved compared with the previous. This hydrophone calibration was finished in National Defense Underwater Acoustics Calibration Laboratory of China. According to the test results, the sensitivity of the hydrophone is -165dB（including pre-amplification 20 dB）, the frequency response ranges from 20Hz to 2kHz (±5dB). And this hydrophone has a good directional pattern in the form of "8"-shape.

Abstract: In the paper, the principle, the preparation and the performance of the dual-color infrared HgCdTe detector is introduced. The detector is a combination of different wave band filter and different respond wave band element. The application of the dual-color infrared HgCdTe sensitive element for methane gas detection sensor is developed. A two-element HgCdTe methane detector which responds between 3.13~3.53μm and 3.91~4.09μm wave bands respectively was reported. The performance of each detection channel was presented. The experiment test and analyze are fulfilled. The experiment result indicates that under the refrigeration temperature the dual-color HgCdTe detector not only has a favorable response ability and repetition but also can realize the response and distinguish ability to methane gas through integrate narrow band filter on the front of the detector sensitive element.

Abstract: In this paper, gold nanoparticles with branches were prepared in aqueous solutions using seed-mediated growth method. The mean diameter of the seeds chosen for these studies is 6~8nm. The influence of reducing agent used in synthesis gold sphere as seeds was investigated. A reaction mechanism of fabrication gold nanostar particles was systematically described. The nanoparticles synthesized were characterized by transmission electron microscopy (TEM) and UV-vis spectroscopy. In order to investigate their optical property, Surface Enhanced Raman Scattering (SERS) spectrums were tested, which showed quite good Raman enhencement.