Advanced Materials Research Vols. 317-319

Abstract: In this paper, identification of dynamic sensing characteristics of MFC(macro fiber composite) and PVDF(polyvinylidene fluoride) are carried out via experimental investigation. A clamped aluminum beam structure is prepared and experimental setup for beam vibration test is established with shaker system. MFC and PVDF are attached on the top and bottom surface of the beam structure, respectively and connected to data acquisition system. In order to verify the operating bandwidth, frequency responses of the smart beam structure are obtained from 0Hz to 5kHz under sine sweep excitation. For the identification of dynamic sensing characteristics, experiments for linearity and durability are conducted. It is observed that both MFC and PVDF have excellent sensing performance in measuring dynamic response and monitoring structural vibration.

Abstract: Abstract. Based on metal oxide gas sensors and DSP technology an odor compass is designed in this paper. Odor compass estimates direction of point odor source by analyzing responses of sensors which are placed on different concentration gradient. Main structure consists of distributed metal oxide gas sensors and plexiglas material. Signal sampling and processing are accomplished by DSP system. The directivity of whole system is tested in uniform wind field. Experimental result shows that the responses for the odor sources with 30°disparity have obvious difference. Ratio of resistance response is selected as characteristic quantity. In this way, influence which is generated from individual difference of sensors is effectively eliminated.

Abstract: The working principle of four-quadrant position sensitive detector(4Q-PSD) as a spot center position measurement detector is presented. Influence of the photoelectric non-uniformity of detector and background light on the detector measurement precision is analyzed. The operational circuit to solve the relationship of spot center position in the coordinates of detector and detector output voltage is designed. And the detector performance testing system based on laser alignment measurement is developed. The relationship between the output voltage of detector and the spot center position in the coordinates of detector is tested. The linearity of output voltage and spot center position in the uniaxial direction of the detector within a small range is good. The influence of measurement distance on the accuracy of the detector is tested. Method of 2-D plane calibration of the 4Q-PSD is proposed, and the detector is 2-D plane calibrated using proposed method. Which extended the available working range of the detector, and with higher measurement accuracy.

Abstract: Node self-localization is one of the key technologies in the wireless sensor networks. The localization technology based on RSSI is a focus studied at the present stage. For the localization error of RSSI-ranged method is relatively great, a kind of triangle centroid algorihms based on RSSI-ranged is proposed. The simulation results show that measurement error of this algorithm effective decrease as to tranditional triangle centroid algorithm based on RSSI-ranged.

Abstract: Until now, no effective method to measure CCD photoelectric parameters. To solve the problem, a novel measurement method that combines hardware with software is proposed, and it can let hardware and software collaborate with each other to finish assignment together. Firstly, the ideal relation between output voltage and input exposure quantity of CCD is given. Secondly, some main photoelectric parameters of CCD are elaborated. Then based on the principle, test system of CCD photoelectric parameters that combines hardware with software is designed. Lastly, the real relation between output voltage and input exposure quantity of CCD is given, and the test results of experiment of each photoelectric parameter are obtained according to the relation. What’s more, analysis and comparison of the results of the experiment are given in this paper. The method is reliable and the precision is high in the experiment.

Abstract: The stiffness of microstructure is an important parameter of the microsensor. It is usually obtained by FEM approach, which is difficult to give an analytical expression. This paper reports on a biaxial microaccelerometer with the crab-leg flexural suspension. Its stiffness is carried out by using force method and Castigliano’s theorem. During the deduction, we neither introduce the other assumptions nor design the special dimension. So this methodology is strict in theory, and can be extended to analysis for the displacement and stiffness of the symmetric and statically indeterminate microstructure.

Abstract: All routing protocols are focused on how to transfer data more efficiently from the source to the destination. But various circumstances have diverse requirements, so the method adopts to achieve this is different. In this paper, we introduce the situation of AODV running in the AMI smart-meter reallity environment and point out the bottleneck of throughput as the networks grow larger. Then, “expected transmission count” metric is presented, which has been proven in other classic routing protocol for high-throughput improvement. After analysing the applicability of ETX metric with AODV, we describe the new AODV with four major changes listed as follow: router table, hello message, neighbor-node table and something related RREQ, RREP, RERR messages. Finally, we compare the results with the traditional AODV. Simulation results in NS-2 show AODV-ETX has better throughput than the traditional one.

Abstract: The quality of elbow flowmeter is important to its application accuracy. This paper described the digital quality evaluating method for elbow flowmeter which based on the analysis of elbow flowmeter’s theory, construction, working condition, and fault characteristics. In the method, we applied the concept of static quality, dynamic quality and used quality index to show the quality condition of flowmeter precisely. The fuzzy math theory, finite element analysis technology and online detection technology were used in our method. The digital quality evaluation system can get more accurate testing values, more stable dynamic performance and faster fault diagnosing for flowmeter .

Abstract: Planar Hall effect sensor has been explored using multi-layer cross-shaped and bridge geometry. We present planar Hall effect in a ring-shaped geometry experimentally that shows progress of sensor sensitivity as well as output signals. Sensitivity improves about 170 times compare to cross-shaped geometry and about 1.4 times to bridge geometry in conventional measurement system. These values become 2.5 times larger at 20o measurement system. The presented ring geometry may take great potential in Planar Hall effect sensor applications.

Abstract: Used Three-stage op amp to design a good performance CMOS integrated charge detection based on quartz gyroscope. In the circuit design, using the PMOS full-differential input and the folded cascade structure, through adjusting the transistor parameters to reduce noise and improve the gain; .Set each transistor’s parameters based on 0.5µm process, use H-Spice software in detection circuit and demodulation circuit for simulation, parameter adjustment and verification. The simulation results contain: the open-loop gain gets to 128.13dB, phase margin 88°, SR gets to 2V/µs, the output noise is 38nV/ at 10kHz frequency, full output swing. The simulation results of output signal show that each 5×10-15C change of input charge amount can provide about 1mV change of output voltage. The voltage signal that obtained by the demodulation circuit compares with the input angular velocity signal has a very highly linearity.