Applied Mechanics and Materials Vols. 268-270

Abstract: To solve the writing and reading operation conflict to RAM in LED/LCD display control system, a new RAM operation conflict arbiter IC was proposed. Comparing the traditional dual ports RAM, the IC has the advantages of low-cost and high stability. By analyzing the working principle and structure design, the IC was designed in pure digital way with Verilog HDL, and passed the simulation verify. Finally the IC was realized by Alter FPGA chip and passed the actual test.

Abstract: In order to realize point-light-source and hurdle lamp LED displays system, a kind of LED display screen controller design based on FPGA and STM32 is introduced by this paper. This design can quickly and easily receive display the data from USB, Ethernet and SD card interfaces through the STM32 processor, and use FPGA to realize data transmission throughput big operation of stable display by double RAM Ping-Pong operation This paper gives drive unit timing for TM1809 series LED drive chip as typical case. This design has applied to LED display controller with stability of reading data and excellent performance.

Abstract: A finite-difference time-domain (FDTD) method for simulating wave propagation in Cole-Cole dispersive media was presented. The main difficulty of the proposed way was the appearance of fractional time derivatives in the FDTD equation. The Padé approximation method was employed to solve this problem. The expansion of the fractional time derivatives could deal with this model. The comparison of analytical and calculated the reflection of a plasma proves the validity of the method. Then apply this method to calculate the reflection of the air-muscle interface.

Abstract: Fatigue fracture is the main style of failure in the metal beam under variable load and the formation of cracks is often the omen of breakage. The detection of cracks ahead is of important significance to prevent the production of vast defect and safety accidents. Loading experiments were performed on metal beams with artificial defects, the Acoustic Emission (AE) signals were extracted in the loading process. The methods like tabulation, the experience diagram analysis, distribution analysis and correlation analysis are respectively used to analyze events, ringing counts, energy counts, maximum amplitude, rise time and duration of AE characteristic parameters. Results show that the method of AE parameters analysis is not only able to capture in real time the development of fatigue cracks, but also fix the preliminary position of the cracks. So it is feasible to detect defects of the metal beam by AE technology.

Abstract: A highly sensitive, simple and selective gas sensor was developed for the determination of trace acetaldehyde in air based on cataluminescence (CTL) on nano-sized Al₂Ti₂O₇. The gas sensor showed high selectivity for acetaldehyde at 515 nm and satisfying activity at 295°C. The linear range of the CTL intensity versus concentration of acetaldehyde was 1~65 mg/m³, and the detection limit (3σ) was 0.5 mg/m³. No interference was observed while the foreign substances, such as ammonia, ethanol, formaldehyde, benzene, carbon monoxide and sulfur dioxide, were passing through the sensor. The gas sensor displayed good stability for continuously introducing 10 mg/m³ acetaldehyde over 60 h, and allowed real-time monitoring of acetaldehyde in air.

Abstract: This paper presents a portable measurement system for the concentration of potassium ions in human vitreous humor. This system mainly consists of three units, which are ion selective electrode, STC89C52 microcontroller and 16-bit AD7705 analog-to-digital convertor. In order to improve measurement precision, temperature compensation was conducted by using DS18B20 temperature sensor to detect ambient temperature and processing data with compensation measures. This system was tested with potassium solution and the precision can reach up to 99.69%. It can measure in situ the concentration of potassium ions in human vitreous humor which can be used to estimate the postmortem interval. The measuring system presented in this paper is easy to operate and can also measure other ions by changing ISE and the value of feedback resistor of operational amplifier.

Abstract: In this paper, we demonstrate ways of identifying audible sound of working engine to distinguish whether it is in normal condition or faulty condition. A set of experiments were carried out on an engine from a heavy trunk, in order to verify the method, allowing the three sensors located on engine surface to accurately adapt the normal signal and the faulty signal. A technique for faulty mode identification on the engine has been developed based on audible sound. In a practical application of the technique to running engines we capture data of audible sound and a series of analysis were acted on the data, then we could acquire the result to distinguish the state of engine.

Abstract: In this paper, based on B & K pulse system, the noise test analysis had been implemented on the load test station of a company in Yinchuan. It is clear and concise that displayed noise distribution situation of the load test set by BK sound intensity probe, 3560B-type multi-analysis system and pc machine. Through the CPB analysis, it can quickly get the main segment of the noise and the real-time monitoring of the gearbox, so the quality of the product is guaranteed.

Abstract: The method of texting a blade’s aerodynamic performance used for traditional wind turbine airfoils was making pressure measurement holes on surface of the blade, but Magnus wind turbine blade must rotated at a certain speed to generate lift and drag force, so the method was inapplicable. A novel experimental device for testing aerodynamic performance of Magnus wind turbine’s cylindrical blades had been investigated. This device, which consists of three parts: cylindrical blade, controlling system and testing system, could measure the lift and drag force generated by the Magnus effect on the blades. This paper mainly studied the testing system,including dynamometer and amplifying circuit. At last, the testing system was used in the experiment to test aerodynamic performance of the Magnus wind turbine blade. The results showed that the system could conduct the experiment on testing the lift and drag force on the Magnus wind turbine blades efficiently, and the system could also be used to measure the lift and drag force on traditional wind turbine airfoil.

Abstract: Experiments were conducted to study the attenuation properties of ultrasonic guided wave propagating in anchored rock bolts. Results show that concrete as anchored material at different curing time can represent different bonding quality, and attenuation coefficient value of ultrasonic guided wave in anchored bolt increases as the increasing of curing time. At the mean time, the attenuation coefficient value becomes larger when the anchored length of rock bolt increases. So attenuation coefficient value is an efficient tool to evaluate the bonding quality of anchored rock bolt.