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In this study, a hybrid steady-state compressor model is proposed that can be used in the real-time performance monitoring, control and optimization of the vapor compression cycle. In the proposed model, first, a detailed analysis of the mass flow rate is presented, which is based on the volumetric efficiency concept and the assumption of a polytropic compression process. Then, discharge temperature of the refrigerant and power consumption of the compressor are also investigated. Three semiempirical models are constructed respectively. Further, to tune the unknown empirical parameters of the models, a social learning particle swarm optimization (SLPSO) algorithm is developed by using the real-time experimental data. An experimental apparatus of a refrigerant system is tested to validate the proposed models. The experimental results demonstrate that the proposed models accurately predict the performance of real-time operating compressors. Meanwhile, the models identified by the SLPSO algorithm are more accurate than those identified by the traditional least-squares method.

This paper develops a Sobol sensitivity analysis model of thrust force of linear switched reluctance motors (LSRMs), to quantitatively analyze the coupled influence of parameters on the thrust force ripple. A nonlinear thrust force model of a developed LSRM is first given. Using Sobol sensitivity analysis method, the local and global sensitivity indexes are deduced according to thrust force model. In addition, applying the deduced sensitivity indexes, local and global sensitivity results of thrust force are obtained, and the quantitatively coupled influence of parameters on the thrust force ripple is presented and analyzed.

The identification of dynamic model parameters of the permanent magnet synchronous linear motors (PMSLMs) is the foundation of high-performance motor control. To address the low accuracy of modelling of PMSLMs, a parameter identification method of the PMSLM is proposed by using multi-innovation least squares (MILS) approach in this paper. The linear transfer function of the PMSLM is first built. Then the MILS approach based on the recursive least squares (RLS) algorithm is developed to identify the parameters of the built model. Finally, the simulation results of MILS and RLS algorithms are shown, and the effectiveness of the proposed method is verified.

Physical model of ventilation system requiring exact knowledge of all component parameters is usual unavailable in practice. Based on this issue, the objective of this study is to develop an air balancing method to predict the damper position provided the desired airflow rate without requiring a physical model. In the study reported here, the proposed air balancing method consists of a multilayer perceptron model and a damper control method. The multilayer perceptron model is constructed and trained to simulate the non-linear relationship between pressure drop and airflow rate at the damper, and the damper position control method is used to relate pressure drop to operating position of the damper. Experimental tests are carried out to validate the performance of the proposed method. The results show that the proposed method is powerful to balance the ventilation system.

To achieve satisfactory positioning performance considering actuator saturation, this article proposes a constrained predictive position control (CPPC) approach using the threshold function for the planar switched reluctance motor (PSRM). For the PSRM designed in our lab, a dynamic model expressed as a discrete state-space model is established. The input thrust force of the position controller is constrained by applying a nonlinear threshold function. Based on the constrained thrust force, a prediction model with constraints, which can predict motor positions in the future, is built. With the cost function developed from the prediction model, the control input is derived through minimizing the cost function. Finally, the results of experiments demonstrate the presented CPPC can availably restrain the input thrust force as well as realize the satisfactory positioning performance of the PSRM.

This article proposes a predictive position control (PPC) approach with stable control parameters of planar switched reluctance motors (PSRMs) for 2-D positioning systems. The motivation is to determine the controller parameters for guaranteeing a stable closed-loop PSRM control system. For the PSRM designed in our lab, the dynamic behaviors are described employing a discrete-time state-space model. Then, a prediction model is built for the position prediction in the future on account of the established state-space model. By minimizing the defined cost function based on the built prediction model, the optimal control sequence is derived. Moreover, the stability analysis is presented and the stable control parameters are determined by using the closed-loop state-space model. Finally, the experimental results verify the validity of PPC approach.

Eu2+ doped Ca 2 Al 2−x Si 1+x O 7−x N x (CASON) green-emitting phosphors were prepared by the high temperature solid state reaction method. The crystal structure and luminescence properties were systematically investigated by X-ray powder diffraction and fluorescence spectrophotometer. It was found that Al-O bond could be substituted by Si-N bond in the Ca 2 Al 2 SiO 7 lattice with the maximum solubility of about x =0.4. Under the excitation of 360nm, the photoluminescence (PL) spectra of Ca 2 Al 2−x Si 1+x O 7−x N x : Eu2+ phosphors presents a blue shift with the increase of x values. The mechanism was discussed in detail by Size-Mismatch model.

A method of untouched measurement based on OpenCV is proposed to achieve the sub-pixel inner diameter Measurement of workpiece. Design and implement a visual measurement system on the inner diameter Measurement of workpiece. In the image, the grayscale of the noise and the aim is very close and very hard to be separated by the right threshold. To this difficult point, a method of two thresholds in two steps is proposed. First, remove the background noise with a smaller threshold; second, get the binarization image close to the real contour of the aim with a bigger threshold. The system deals with the image binarization, the interception of region of interest, contour extraction and so on, finally achieves the high-precision inner diameter measurement of workpiece. Repeat the measurement many times of the workpiece in different place in the field of view, the experimental results show that the consistency of the method is better than the HALCON machine vision software.

This work discusses the concurrent applications of data collection and reconfiguration, and proposes a novel reconfiguration scheme during data collection. The proposed scheme incorporates the advantages of both proactive and reactive protocols into one system: using proactive protocol to collect continuous data and reactive protocol to reconfigure each remote node of the network. In addition, three methods with suppression mechanism are proposed in which two using the topology information as hints and one using simple flooding. Finally, we propose a cost-saving and reliable reconfiguration scheme during data collection to efficiently combine the table-driven data collection tree and three reconfiguration methods. The results of simulation show the effectiveness of the scheme.

For comparing the stability and reliability of horizontal, vertical and flip LED chips, we carried on the high temperature and high current aging experiment towards to the three kinds of bare LED chips on our self-build online monitoring and accelerated life system. Most of samples shown stable performance during the entire experiment process, but there was only one flip LED chip whose illuminant, electrical and thermal performance degraded from the beginning of the test. Comparing with the normal LED flip chips, the abnormal chips' illuminant flux decreased during the whole experiment, meanwhile its forward bias and junction temperature increased as shown by the online monitoring system. We carried out anatomy and grinding towards to the abnormal chip and its reference normal one. We found that the silver refracting layer was oxidized which was main reason of the abnormal chip's performance degradation.

As known to all, photometric and colorimetric quality of LED illumination mainly depends on LED chip, phosphor and sealant. The investigation on failure mechanism of the three parts carries critical meanings for improving reliability of LED production. This paper mainly focus on reliability and failure mechanism of the three kinds of phosphor and three kinds of sealant which are wildly used in high power white light emitting diode package. In this work, high temperature-humidity aging experiment and other material science related detecting methods were involved. We prepared phosphor samples by stamping phosphor powder into pieces before aging experiment. After high temperature-humidity aging experiment, we found that aluminate based phosphors show excellent stability compared with silicate based phosphor. The silicate based phosphor will turn to amorphization in high temperature-humidity environment. Its composition and morphology will be changed greatly. We fabricated blue LED modules which were filled by three kinds of different sealants. After 300 hours high temperature aging experiment, silicone based sealants (methyl silicone and phenyl silicone) have shown much better thermal stability than epoxy resin based sealant. Two kinds of silicone based sealants only appeared slightly yellowing, but epoxy resin occurred serious carbonization.

Single channel wireless sensor networks may be unreliable when the channel of choice is either unstable or interfered. Previous work has shown that multi-channel solutions could effectively improve network reliability and deliver higher throughput as well. While a number of multi-channel medium access control schemes have been proposed, there are not much work on routing protocol design addressing the unique challenges multi-channel schemes are facing. In this paper we present a multi-channel cross-layer tree routing protocol. Our contribution includes: Adaptive beaconing corresponding to network topology; Beacon-driven, send-data and receive-data driven link quality estimations; and synchronized MAC and routing table management. Our protocol has been implemented on a testbed consisting of 53 nodes deployed in a 5-story building. Experimental results show that our approach provides fast convergence rate, stable topology and over 99.8% data transmission reliability.

This paper presents a reconfigurable mechanism for the multiplier. The proposed mechanism is applied to generate a multiplier, whose data width, type and pipeline depth can be customized. The data width of each operand of these generated multipliers can be configured for 4i where i=1, 2, 3, 4, 5, 6, 7, 8. And the data type of operand can be unsigned or signed at will. The multiplier is composed of the smallest multiplier-cells, the 4bit multiplier. Synthesized results could reach as high as 425.53MHz using SMIC 0.13um CMOS technology library under the worst case condition.

A project of the wireless video monitoring system based on the Web has been worked out and applied to the freeway's toll station. The video signals will be collected by the camera and then be coded. The Winsock through the Internet will transmit all the video data. With this technology application, the workers can inspect the real-time pictures and data shot by any one of the cameras and control the monitoring devices at the spot.