A Method for Correcting the Interference of Overlapping Absorption Lines Using Second Harmonic Spectral Reconstruction

The measurement accuracy of trace gas detection based on infrared absorption spectroscopy is influenced by the overlap of absorption lines. A method for correcting the interference of overlapping absorption lines using second harmonic spectral reconstruction (2f-SR) is proposed to improve the measurement accuracy. 2f-SR includes three parts: measurement of gas temperature and use of the differences in temperature characteristics of absorption lines to correct the temperature error, 2f signal restoration based on laser characteristics to eliminate the influence of waveform change on overlapping absorption lines, and fast multi-peak fitting for the separation of interference from overlapping absorption lines. The CH4 measurement accuracy based on overlapping absorption lines is better than 0.8% using 2f-SR. 2f-SR has a lower minimum detection limit (MDL) and a higher detection accuracy than the separation of overlapping absorption lines based on the direct absorption method. The MDL is reduced by two to three orders of magnitude and reaches the part per million by volume level. 2f-SR has clear advantages for correcting the interference of overlapping absorption lines in terms of both MDL and measurement accuracy.

A Load Modeling Method Based on Machine Learning

More and more high-power impact loads in the power grid are put into use. When the power is impacted, these loads will cause the power grid bus voltage fluctuations and reduce the power quality. Therefore, in order to accurately analyze the changes in the power system, it is particularly important to establish a reasonable impact load model. This paper takes the impact load data generated by the CT machine during exposure as an example to analyze the characteristics of the impact load. Based on the active power characteristics of the impact load, machine learning methods (such as support vector machines and long and short-term memory networks) are introduced into the impact load modeling, and the power waveform change law of the impact load is accurately established by this method. Finally, the effectiveness of the method is verified by simulation.

A Simple, Cheap and Precise Microcontroller Based DDS Function Generator

In electronics design and troubleshooting, the function generator is an important and versatile electronic test equipment. But the prices of finished function generator sold on market is expensive and not everyone can afford it. In order to create an economic and reliable function generator, microcontroller-based DDS function generator designed. AD9833 is DDS based programmable function generator from Analog Devices, which capable to producing sine, triangular and square wave output. To make an easy to use and flexible function generator, AD9833 connected with 4x4 matrix membrane keypad and LCD 1602. The microcontroller-based DDS function generator successfully created. The waveform generated by AD9833 offers not only exceptional accuracy and stability, but also low phase noise, an excellent frequency change and sudden waveform change ability, its useful in a wide variety of testing applications.

Artificial Intelligence Based Discrimination of Transformer Inrush and External Fault Currents

The function of a power transformer defensive transfer is to work rapidly during the issue condition and to square the stumbling during the other working states of the power transformer. Another method for arranging transient miracles in power transformers, which can be executed in advanced handing-off for transformer insurance. Separation among various working conditions (Transformer, external fault) Power transformer is accomplished by incorporating waveform transformations along the neural network. The waveform change intensity transformer is connected to the transient miracle probe, as a result of its capacity to remove data from the transient sign all the while in both time and recurrence area. The nervous system is used in light of its self-learning and exceptionally nonlinear mapping capability. The proposed scheme has been accepted through artificial neural network (ANN) designs. ANN engineering was designed to use BPN (back propagation calculation) alone, and BPN was consolidated with waveform transform (WNN), so it ought to perceive and order all the above working conditions and blames. The reenactment results got demonstrates that the new calculation precisely gives high working affectability to inside issues and stays stable for other working states of the power transformer. From that it was gathered that the consolidated WNN gives increasingly precise outcomes and it has fast reaction and expanded capacity to separate even low-level deficiency signals from other working conditions.

Leakage Line Detection Based on Improved Grey Absolute Relation Degree Model

For the defects of traditional grey absolute relation degree, the improved grey absolute relation degree model is presented. Compared with the traditional one, this improved model is more excellent in characteristic, and which takes on consistency and isotonicity; and then the veracity and reliability of grey relation analysis are enhanced. Using this new model to discriminate waveform change rate of zero sequence currents in fault transient course, the leakage line detection method is established. The simulation and lab test indicate that this method can rapidly detect leakage line self adapting in transverse direction, algorithm is simply, and not influenced by random factors.

Characterization of Plasma Electrolytic Oxidation Films Formed on AZ31 Magnesium Alloys by Different Voltage Parameters

Plasma electrolyte oxidation films (PEO) on AZ31 magnesium alloy were prepared in alkaline silicate solutions with two kinds of voltage waveforms (constant voltage waveform and escalating voltage waveform). Discharge characteristics and the dielectric barrier layer formation of the films formed under two voltage waveforms were investigated. Structure, composition, morphology and corrosion resistance characteristics of the films were studied with scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and potentiodynamic corrosion testing. The porosity of the films was calculated with Mat lab software. Structure, composition and porosity of the films are correlated with changes in behaviors of spark discharges on the surface in oxidation process. The escalating voltage waveform strongly affects the transformation of Mg2+ from the substrate but not the SiO32- ions in the electrolyte and the compactness of dielectric barrier layer. The films formed under escalation voltage waveform exhibited lower porosity and higher corrosion resistance than the films formed under constant voltage waveform because of less defects on the surface of the films. The voltage waveform change has little influence on the thickness of the films.