Applied Mechanics and Materials Vols. 241-244

Abstract: The approximate realization methods of system with Gaussian characteristics for inductive micro-displacement sensors were studied in this paper. It was assumed that the sensors used were the first-order systems, for such sensors, it was first proved that cascaded systems formed by an infinite number of first-order systems, its characteristics will infinitely approximate to be those of the Gaussian system. In other words, the cascaded system of a finite number of the first-order systems which have the same characteristics is a Gaussian approximation system. This law can also be applied to the second-order systems, and to the first-order and second-order mixed systems. Theoretical analysis shows that the maximum deviation of Gaussian approximation that 16 cascaded first-order systems is 1.4%, and the maximum deviation of the Gaussian approximation that 16 cascaded second-order systems is 0.1%. This law provided a theoretical guidance for the design of the Gaussian system, which makes the application of the Gaussian system for the geometric multi-probe measurement system to be easy and possible.

Abstract: All the effects of manufacturing errors on transmission spectrum are analyzed for a vertical coupling microring resonator (MRR). Results show that the core refractive index, core thickness and radius errors of ring result in central wavelength shift of the transmission spectrum, and the central deviation and thickness between the ring and channel lead to nonresonant light intensity change. In order to obtain satisfactory spectrum for a fabricated MRR device, some allowed manufacturing errors are discussed, and the accumulation and compensation of manufacturing errors are investigated.

Abstract: An intelligent method based on multi-sensor information fusion is put forward to resolve the problem lay in hydraulic system fault diagnosis. Determining how to choose sensors used for information acquisition is the main objective. Test signal directed graph and dependency matrix model are established to realize optimal design oriented by the maximum failure information entropy.

Abstract: This paper provides an overview of the sort of motor’s losses, analyzes and expatiates on several methods of testing for efficiency, designs a set of scheme for motor energy efficiency testing. The test platform can achieve the aim of resistance measurement, temperature measurement, power analysis and data processing and other test. The system can further improve the authentication level of the motor, system testing results can provide the basis for the relevant departments of the state. Practical application shows that the detection result of this system is reliable and accurate.

Abstract: This template explains a design of a fuzzy temperature control system for the pressure-sensitive paint. According to the relationship between temperature difference and the current of semiconductor chip, the fuzzy system control theory, control the volume of the domain, control rules design, and design a constant current source circuit to control the current through the chip, and finally make experimental verification of the system. The system hardware uses C8051F040 MCU, temperature chip DS18B20, keyboard chip CH451.

Abstract: A method of mixed gas quantitative analysis with near infrared spectroscopy （NIR）is described. A single plane diffraction grating is used in the monochromatic spectrum system. A quantitative analysis system is designed and constructed according to the parameters of the monochromator. The narrowband beam testing and spectral scanning experiments with methane and ethane are carried out. A 10nm narrowband beam is successfully obtained by the monochromatic system when the entrance slit width is 2mm. And a step-scanning resolution of the outgoing beam’s centre wavelength with 0.1nm can be realized within the spectra of 1.0-1.8μm. The results show that methane and ethane have a maxim characteristic absorption spectrum respectively with the centre wavelength of 1653nm and 1690nm existing between the spectra of 1.6-1.8μm, which is consistent with the HITRAN database. Presented approach has a successful application in online mixed gas monitoring with the characteristics of simple structure and low cost.

Abstract: Groundwater level data in paddy rice irrigation region are the important basis for rational utilizing groundwater resource. According to current situation of backward measuring methods to groundwater level in irrigation region, and the characters of monitoring sites dispersion and long distance, distributing control system structure was applied. The microcomputer served as upper machine manages the lower machine and processes the data. MCU served as lower machine instantaneously measures water level. Wireless communication modules were applied to transmit data. Experiment was conducted in Jianshanjiang agricultural department. The results show: quantity of testing site in network up to 65536, max error 0.49%, collecting time 5～10s, power consumption 2.4W, and idle mode consumption 72mW. This system has the characters of lower consumption and cost, high dependability, convenient network management.

Abstract: To ensure both performance and security of grid-connected photovoltaic inverters(PVI), a detection platform for grid-connected PVI is researched. The testing method and procedures of grid-connected PVI are analyzed and the development course of this detection platform is described in detail. The detection platform consists of control computer, data acquisition system, RS 485 and GPIB system. In this platform, the solar-cell panel is simulated by programmable DC source, the power grid characteristics of power grid by programmable DC source and the load characteristic by programmable controlled RLC load. The whole detection system is controlled by LabVIEW software interface. The proposed detection platform can be used in the testing of electric performance, protection function, EMC and so on. Practical application shows that the configuration of this detection platform is rational and reliable，and its detection results are accurate.

Abstract: A dodecahedron non-orthogonal redundant IMU configuration was selected as model. To improve fusion accuracy, we proposed an effective calculation method for measurement errors based on the correlation between measurement errors and fusion errors. The method considered the difference between traditional data fusion vector’s projection and measurement results, and then made a conversion from projection error to measurement error. Combined with optimal weighted least square method, measurement error was used to generate an optimal weighted matrix, and this made data fusion errors minimum. Simulations also proved that the fusion result of this method is more accurate than the result of traditional method.

Abstract: A new type of cooling device used for server is designed in this paper. A small type of server is taken as a research object to compare the effect of air cooling and evaporative cooling under different CPU power consumption. The effects of this research are discussed on evaporative cooling for the stability of the CPU heat dissipation and the cooler on other components. The results show that the temperature distribution of the server’s case is more uniform and the temperature test of the CPU is more stable when it is cooled by evaporative cooling.