Applied Mechanics and Materials Vol. 441

Abstract: Equivalent elastic parameters of the honeycomb core considering the effect of extension or contraction deformation, shear deformation and flexural deformation are presented in this paper. Then the energy theory is applied to the calculation of the equivalent elastic constants Ee and νe. Finally the accuracy of the formulas have been verified by the compressing experiments with aluminum honeycomb core in the literature[9].

Abstract: In this study, thermal analysis and thermal shock test of 8wt.% yttria stablized zirconia (8YSZ) thermal barrier coatings (TBCs) on low heat rejection (LHR) diesel engine have been conducted. The influence of TBCs on temperature distribution of piston was discussed by employing ANSYS codes. The thermal shock resistance test was carried out by placing the samples under flame jet heating and compressed air cooling in turn. Two kinds of thermal cycling modes with different periods were used to investigate the role of cycling frequency in coatings failure. As the frequency rose, the service life of coatings significantly decreased. The spallation of coatings happened at the interface between bond coat and substrate. The stress calculation results indicated that considerable stress caused by thermal mismatch was one of the main reasons for TBCs failure. The heat affected zone (HAZ) under the bond coat inhibited the diffusion between the bond coat and substrate. The oxide layer consisting of Mg and Al oxides under the HAZ was harmful to the bond between bond coat and substrate, which was another main reason for the spallation of coatings.

Abstract: Agricultural bird damage problem has been a hot issue trouble all the time, how to not only protect the birds but also put the economic-threat to birds under economic threshold at the same time has become the focus to the current research. The system on the basis of Intelligent Voice--driving Bird Dispeller, puts forward the STC89C58RC/RD and single-chip microcomputer as the core, including SMS module, photosensitive module, AD convert module and MP3 audio module which is composing of a portable intelligent voice anti-Bird Device. The system detects the outside light intensity by the photosensitive module, and the GSM module receives the remote control signal which is from the GSM mobile phone, the MP3 module will be controlled by the power relay, the MP3 module receives the command, then PLAY/STOP the voice on U disk, which can achieve the driving field vermin. It is proved that the system is not only easy to operate, saving costs, but also make a profound difference to drive birds with good results by the field experiment. Meanwhile, as long as changing the sound file, the device can be applied to drive rats, drive wolves and other occasions.

Abstract: In this paper, an electronic piano performance system is given. Within the system, a traditional piano keyboard is retained, and a micro-controller unit (MCU) C8051F340 is applied to scan the key value, velocity of the keyboard and send the scanned data to principal computer (PC) via universal serial bus (USB) interface. In addition, application software for PC has been developed to simulate the sound function of a traditional piano, which can identify multiple key values and distinguish between light and heavy sound simultaneously. Finally the design results have proved the validity and utility of our performance system by virtue of lower cost and more accurate and adjustable tones.

Abstract: This paper proposed a versatile signal generator which employed an ARM Cortex^TM-M3 Core as the CPU, a direct digital synthesizer (DDS) chip and a mixer to make the phase modulated signal for GPS jamming. And due to the two parts of the generator, it could be used for intermediate frequency generating and the microwave frequency generating respectively as other two types of generators. With the system, a narrow-band jamming was demonstrated by spectrum and oscilloscope tests for the signals. And the infield test showed the effective range of the jamming was about 200 meters.

Abstract: In order to study the effect on heat transfer performance of evaporator in the gravity feed liquid refrigeration system the different evaporator area, the simulation procedure is worked out. The procedure uses the visual basic language. The procedure can figure out the heat transfer coefficient and the temperature difference in different evaporator area and evaporating temperature with the required refrigerating capacity. Through simulation calculation, when the area is 80% of the original design area of evaporator, the evaporator of the heat transfer coefficient and heat transfer temperature difference is the most reasonable and the evaporator of the refrigerating capacity can meet the requirements of cold storage. The program provides the reliable data for the gravity feed liquid cooling system optimization.

Abstract: In order to reflect the input and output features of an optical fiber micro-bend sensor, a new method using general regression neural network (GRNN) to fit the characteristic curve is proposed in this paper. First, the measuring principle of optical fiber micro-bend sensor and the principle of GRNN are introduced. Then, to verify the feasibility and effectiveness of this new method, a comparison between two kinds of fitting methods is done. One is based on GRNN, the other is based on Levenberg-Marquart improved BPNN. The results of the simulation experiment show that with the same number of training samples and for small scale to medium scale networks, compared with BPNN, GRNN has smaller error, faster convergence speed and higher fitting accuracy. So the method discussed in this paper provides a reliable basis for the nonlinear compensation problem of optical fiber micro-bend sensor.

Abstract: The current situation and the important role in power system of the time keeping system is described. It analyzed some questions which has been met in the development of the time keeping system and designed a time keeping system by GPS or Beidou as time mark.The double constant temperature trough crystal oscillator MV180 was used as the input clock of system, and used SCM control DAC7512 to adjust its frequency. The system carries on the frequency division processing to the adjusted local clock signal, then compares with the standard second signal received by the GPS or Beidou, adjusts the phase of the signal through frequency division by using FPGA and SCM, and finally, outputs the standard second pulse. It also can maintain the signal invariably after GPS or Beidou lock-lose to achieve the time synchronization of power system.

Abstract: A clock-inverter feed-forward toggle flip-flop (CIFF-TFF) based ultra-high-speed 2:1 dynamic frequency divider is designed in a GaAs heterojunction bipolar transistor (HBT) technology with f_T of 60 GHz from Win Semiconductors corporation. The co-simulation methodology of electromagnetic field and schematic diagram is utilized in the design. Through tuning the currents in the core and the other parts of the divider separately, the dynamic frequency divider approaches an operating speed of 36 GHz with a power consumption of 162 mW in the core part from a single 6 V supply. The design is currently taped out.

Abstract: This paper presents compact design and implementation of a portable device for application of continuous Electrocardiogram(ECG) and respiration measurement in the field of dynamic health monitoring. Bluetooth technique is used for data transmission between portable device and acquisition node such as computer or smart phone, given its advantages of low power consumption and easy wireless connection. The device also includes a wireless power module for charging the lithium polymer battery with the charging current up to 300mA, which makes power supply much more conveniently. Measurement of ECG and respiration is implemented by two electrodes layout solution and ADS1292R which enable the system design at significantly reduced size(60mm*40mm), power, and overall cost. Experiments are carried out with appropriate work parameters as sample rates and resolution. The results show that our device can accurately acquire the ECG and multiple respiration states..