Advanced Materials Research Vols. 605-607

Abstract: A sensitive cataluminescence (CTL)-based gas sensor using nano-sized Y₂Ti₃O₉ as a probe was proposed for the determination of trimethylamine (TMA) in air. The gas sensor showed high selectivity for TMA at 490 nm and satisfying activity at 320°C. The linear range of the CTL intensity versus concentration of TMA was 1~70 mg/m³ (γ = 0.995), and the detection limit (3σ) was 0.6 mg/m³. No interference was observed while the foreign substances, such as ammonia, ethanol, benzene, carbon monoxide and sulfur dioxide, were passing through the sensor. The gas sensor displayed good stability for continuously introducing TMA over 100 h, and allowed on-line monitoring of TMA in air.

Abstract: Aiming at amplitude decay with the change of the varying conditions problems in ultrasonic honing processing, this paper puts forward to the frequency of ultrasonic machining testing solutions. By measuring the change of the input current transducer, adjust the ultrasonic generator power output, and ensure that the ultrasonic generator adjust the output power according to load. Finally, stable amplitude, make the whole system in a resonant state, the amplitude of the oil-stone keep near biggest amplitude. This paper designed circuit measuring the current which can feedback current changes effectively, to provide the safeguard for adjusting the ultrasonic generator output power.

Abstract: The granary temperature and humidity detection system, it is used AT89C51 as the main control core, and used the RS232 bus communication to realize the granary temperature and humidity control. The host microcontroller is depended on the AT89C51 to drive, and to display temperature, humidity and brightness, at the same time through the keyboard to enter the master information. The attached master machine used STC12C2052AD as the control unit, the Digital Temperature and humidity data acquisition used sensor SHT11, in each of the master machine and attached machine use of serial communication. When the temperature and humidity exceed the set values, it will alarm.

Abstract: Research on the rheological characteristics and delivery resistance needs precise flow rate in pipes of thick pastes which is the basis of delivery capacity calculation and equipment selection for a pipeline system. However, the existing apparatuses are not suitable for flow rate measurement of the thick pastes, so it is necessary to design a kind of apparatus applicable to the above requirements. This paper by using an electromagnetic induction coil as a sensor, designs a kind of flow rate measurement apparatus of thick pastes. It describes the measurement method and its principle, and analyzes the error of this apparatus. A loop-pipe transportation test of coal slime was conducted, and it shows the relative test experimental error of this apparatus is less than 1%.

Abstract: Taking elastic deformations of the platform and sensors into consideration, a simplified model of three-point supporting type barycenter measurement system was built. The tilt-angle calculation formula of the measured object caused by elastic deformations was obtained through the physical and geometrical analysis. Then the principle error of barycenter eccentricity was calculated in measurement process. On study of the principle error expression, it was concluded that measurement value of barycenter eccentricity is greater than the actual; the value of the principle error is proportional to the weight, the barycenter height and the actual barycenter eccentricity of the measured object, and is inversely proportional to the square of the distributing radius of sensors, the synthetic stiffness of the stacking part of platform and sensor. But the principle error has nothing to do with the phase angle of barycenter. Finally, simulation experiments were done using Adams. The experimental results agree well with the conclusions of theoretical analysis.

Abstract: This paper mainly introduces a FPGA-based data acquisition system which is designed to acquire multi-channel analog signal and one channel digital signal. Analog data and digital data are stored into a FLASH memory in a mixed frame format. When the acquisition finished, the data in the FLASH was read out via the LVDS communication interface to a data-read device, and the host computer receives the data through the USB bus, so the subsequent data processing and analysis can be accomplished and the information we needed can be got. The design is applied successfully to a remote measurement system, and the data acquired is reliable and precise.

Abstract: The attenuation behavior of acoustic wave in ER fluid which was made by mixing starch in silicon oil was studied through experiments. The results demonstrate that the particle concentration of fluid and the intensity of extra electric field have certain influences on the attenuation behavior of acoustic wave passing through ER fluid. When othe conditions are fixed, the amplitude of acoustic wave passing through ER fluid increases along with the increasing of particle concentration or field intensity; meanwhile, the acoustic wave presents attenuation with the increasing of distance measured, and its trend slows down when the concentration or field intensity increases. The analysis indicates that the solidification effect of ER fluid caused by extra electric field may be the reason for these phenomena.

Abstract: Abstract:One measurement system of coaxiality error aimd at large-scale holes is introduced in this paper, laser probe is used in the equipment to sample surface of the holes and realize non-contact measurement , actual surface profile signal of every cross section is obtained . The threshold de-noising approach based on wavelet transform is proposed for original signals to improve the measurement accuracy . After computing centre coordinates of every cross section based on least square principle, the reference axis is matched , so the evaluation rule of coaxiality error is deduced and the mathematical model is estabished. Experiment show that the method is accurate and reliable , simple and practical , so it can meet the requirements of high accurate measuring for large-scale holes at the industrial scene completely.

Abstract: According to the vehicle braking efficiency road test rules in GB7258, the braking efficiency on-line monitoring index, parameter, method and threshold are studied. Mean fully developed deceleration (MFDD) is selected as the evaluation index. Pitch angle which is used to monitor the road slope(less than 1%) is collected by gyroscope. Vehicle maximum deceleration is collected at the period of ABS working, which is to make sure that the road adhesion coefficient is more than 0.7. Vehicle maximum braking deceleration is analyzed, and it is used to exclude driving on pit, decelerating band, road step, even crash and so on. The rapid stop is identified with brake pedal travel senor. MFDD is calculated with braking deceleration and wheel speed, and wheel speed is collected from ABS with can bus. MFDD threshold is determined with passenger capacity monitoring with card reader. Finally, the method of vehicle braking efficiency on-line monitoring and evaluation with MFDD is given.

Abstract: Geometric errors are seldom considered the generations of CMM dynamic errors. This paper presents the dynamic effects of the geometric errors of CMM in fast probing, and investigates the properties with Finite Elements Method (FEM). The FEM model was composed of CMM moving bridge and its guide way. Presuming CMM guide way as an ideal rigid geometry, then angular errors were generated by the rotations of guide way around a corresponding coordinate axis, while translation errors came from the translations of guide way. Thus the 6 geometric errors on each guide way were completely decoupling and the corresponding dynamic effects were studied respectively. Analyses show that the angular errors around Y and Z-axes, Y(x) and Z(x), can induce remarkable dynamic effects at probe tip, especially in a CMM with low stiffness air bearing.