Applied Mechanics and Materials Vols. 530-531

Abstract: Abnormal dilation and tortuosity of retinal blood vessels are the primary signs of plus disease in retinopathy of prematurity. Timely prognosis could help reduce the delay in treatment and the risk of retinal detachment. Our objectives is to determine whether tortuosity and dilation sufficient for plus disease could be assessed most accurately by considering only arterioles, venules, or both. Tortuosity estimation and width measurement is done using previously proposed methods. Image preprocessing is applied before the two features namely, tortuosity and width of blood vessels are estimated to supply as input parameters for classification using K-means clustering technique. The results are validated by comparing with expert ophthalmologists ground truths. Performance is evaluated based on measures as sensitivity, specificity, predictive values and accuracy. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy values obtained when considering both the arteriolar tortuosity and venous dilation are 85.86%, 90.74%, 88.76%, 88.28% and 88.50% respectively.

Abstract: Aiming at the shortage of lowprecision harmonic wave's analysis in China, and the inadaptability of error transmitting, we analyze the error sources and come up with an approach, Direct Data frequency Synthesizer (DDS), to replace the traditional analog Phase Locked Loop (PLL) to track the frequency of measured signal. Non-integer-period Discrete Fourier Transform (DFT) compensation algorithm is used for processing data. Accordingly a high-precision harmonic standard device is designed in this paper. The final test shows that this solution can efficiently improve the precision.

Abstract: Present our water pollution has become a prominent issue, in order to further enhance the water quality testing and management, so the paper designed the system has easy to carry and test simplify, etc. because of the system using neuron 3150 chip as the main processor, the circuit is easy to design. The system is according to water quality, dolor reactants which are chosen according to the measured parameters have different spectral absorption characteristics. At the characteristic absorption wavelength, the absorption of light energy depends on the content of the measured ingredients.

Abstract: Seam tracking technology is an important area of research automatic arc welding, precise seam tracking is crucial to achieve high quality welds. In order to achieve precise seam tracking, seam deviation (the weld center arc deviation) detection is a key. Unlike the conventional method by image processing techniques to obtain the seam deviation information directly, but selected image processing area (including the distal end portion of the molten pool welds and the front end of the pool), and analyzed as a pool image centroid characteristic parameters of the weld deviation. Study these parameters to create a new method for visual weld deviation measurement model, establish the weld center neural network model using artificial neural network modeling technology.

Abstract: Information processing module, which includes fuel cell sensor circuit, pressure sensor circuit, heating and temperature sensor circuit and signal filtering amplifier, is the core of Intelligent Alcohol Tester. Its main task is to complete the collection and pretreatment of alcohol gas signal. In this paper, the hardware module is first simply introduced. And next, test method and the relevant criteria are done to prove that the modules have good accuracy and stability and achieve the requirements of alcohol tester.

Abstract: In this paper, a high performance current-mode instrumentation amplifier has been proposed with low noise, low power and high CMRR features. The proposed design can adjust the gain with an external resistor for the processing of various biomedical signals. To reduce the noise of the amplifier, two design methods including PMOS input and lateral pnp BJT input have been implemented to improve the prior arts. To meet the single power supply need, a biomedical voltage level shifter is also proposed for low cost CMOS implementation. Based on the post-layout simulation results, the presented current-mode amplifier achieves high CMRR over 120 dB, power consumption of 61 uW at 1.8-V supply using standard 0.18-um CMOS technology.

Abstract: This article introduces the application of the MDD(Multi-depth Deflectometer) in the asphalt concrete concrete pavement. By analyzing its work principle, MDD was calibrated to get the real response of the pavement structure and reveals its true condition. It also introduces the details of the MDDS installation and illustrates the analysis of the typical response date, which is helpful for the further application of MDD in the asphalt concrete pavement design.

Abstract: This paper studied the principles of thermal gas mass flow meter. According to the car engine EGR cooler working principle, we found out a kind of heat dissipation gas mass flow meter to measure the mass flow quantity of the gas in the EGR cooler test and analysis system which is a newly applied invention patent. We analyzed various parameters of the gas mass flow meter suitable to the system. Meanwhile, in order to verify reliability of the thermal gas mass flow meter in the system, we adopted CFD method to simulate the EGR cooler by using empirical parameters, and collected several related sensor parameters of the EGR cooler in the condition that the inlet temperature was constantly at 368K while the coolant had 4 kinds of degrees. Combining heat empirical formula, we got the EGR cooler outlet temperature and the overall heat transfer coefficient. After comparing the calculated values of the gas path total EGR cooler outlet temperature and heat transfer coefficients with the experimental values, we found that the outlet temperature values of experiment were smaller than the calculated values by averagely 1.17%, while the average experimental values of the overall heat transfer coefficient were 3.1% larger than the calculated values. Thus, this type of mass flow meter has good stability in the newly applied Chinese patent EGR cooler performance test and analysis system.

Abstract: A portable digital liquid density measurement system was designed. According to Archimedes principle that a sinkers buoyant force in some liquid is related with liquid density, the system proposed converted analog signal of a pressure sensor into digital signal which can be processed by AT89C52 microcontroller using ADHX711 with high accuracy. Temperature calibration was considered in data processing, which made it possible to accurately measure liquid density at different temperatures. Experiment results show that the method proposed is superior to traditional methods.

Abstract: Magnetic guidance drilling technology is use of magnetic guidance instrument measuring the distance between the signal source and the location of the instrument, and it is used to control the well trajectory to connect or parallel the target layer. And it is an effective supplement of the existing steering drilling technology. At present, the magnetic guidance drilling technology is mainly applied to drill horizontal wells in pairs for the super heavy recovery, CBM horizontal connected wells, underground soluble minerals, relief well and so on. This paper introduces the data processing and the related software development of the active magnetic measuring instrument.