经验模态分解方法及其实现

经验模态分解方法可以有效提取非线性非稳定信号的瞬时特征。提出了经验模态分解方法中“筛”过程存在的端点问题、循环终止条件等重要问题的解决方案;并以经验模态分解方法为核心实现了非线性非稳定信号处理系统,在给出该系统如何处理外来信号流程图的同时,对系统界面的功能、生成方法和运算模块的功能、结构进行了详细地阐述。

A study of particles penetration in sieving process on a linear vibration screen

This paper presented an investigation of particle collision and penetration using the discrete element method to understand the motion of particles and improve theoretical treatment in the sieving process. The process progressively was divided into looseness, stratification, collision, and penetration. Particle penetration has a direct effect on the screening performance. The penetration probability was defined, and the mathematical relationships between particle penetration and vibration parameters were established using the least squares method. To obtain the ideal penetration probability for materials the amplitude and frequency should preferably be near 3.0 mm and 25 Hz, respectively. The vibration direction angle has only a slight effect on penetration. The stage of the screening process from 0.1 to 0.7 s is the primary region for collision and penetration. This paper focused on the sieving process to more fully understand how particle collision and penetration influence the screening efficiency.

Synthesis of FER zeolite with piperidine as structure-directing agent and its catalytic application

The synthesis of ferrierite(FER)zeolite using piperidine as an organic structure‐directing agent was investigated.X‐ray diffraction,X‐ray fluorescence,N2‐adsorption,and scanning electron microscopy were used to characterize the crystal phases,textural properties,and particle morphologies of the zeolite samples.The crystallization behavior of the FER zeolite was found to be directly related to crystallization temperature.At150?C,pure FER phase was observed throughout crystallization.At160–170?C,MWW phase appeared first and gradually transformed into FER phase over time,indicating that the FER phase was thermodynamically favored.In the piperidine‐Na2O‐H2O synthetic system,alkalinity proved to be the crucial factor determining the size and textural properties of FER zeolite.Furthermore,the obtained FER samples exhibited good catalytic performance in the skeletal isomerization of1‐butene.

A Frequency-Response Study on Sorption of Thiophene and Benzene on NiY Zeolite

The adsorption behavior of thiophene and benzene on NiY zeolite has been investigated by the frequency response(FR) method.The FR spectra of thiophene and benzene on NiY zeolite were recorded at 302-335 K in a pressure range of 26.6-266 Pa.The results showed that adsorption was found to be the rate-controlling process for the thiophene/NiY zeolite system,and there were two different adsorption processes.Two kinds of adsorption models have been proposed,namely:the S-M interaction(low frequency adsorption) and the π-complexation(high frequency adsorption).High frequency adsorption obeyed the Langmuir model.By combining the FR method and Langmuir model,the adsorption site of high frequency adsorption process at 302 K and 335 K was 3.172 mmol/g and 2.974 mmol/g,respectively,and on the combined adsorption isotherms,the adsorption site of the low frequency adsorption process at 302 K and 335 K was 0.308 mmol/gand 0.436 mmol/g,respectively.The low frequency adsorption process(S-M interaction) was the main adsorption process.The diffusion process was the rate-controlling process for the benzene-NiY zeolite system.

Study on the numerical simulation of batch sieving process

Screening was widely used in many sectors of industry. However, it is rather incomplete to the cognition of the sieving process for us due to the daedal separation process involving interactions of thousands of particulates. To address this problem, two dimensional numerical simulation of batch sieving process was performed by adopting advanced discrete element method （DEM）, which is one of the highly nonlinear digitized dynamic simulative methods and can be used to reveal the quantitative change from particle dimension level. DEM simulation results show that the jam phenomena of sieve-plate apertures of the ＂blinding particles＂ in the screen feed can be demonstrated vividly and results also reveal that the velocity of particle moving on the screen plate will vary along with the screen length. This conclusion will be helpful to the design and operation of screen.

Study on Crystallization of Titanium Silicalite Zeolite (Ⅱ)

In order to investigate the rules on formation of zeolite during crystallization of titanium silicalite zeolite (TS-1) the X-ray diffractometry and Foulier transform infra-red spectrometry were applied to track the process of crystallization of titanium silicalite zeolite. The research results revealed that at the initial stage of crystallization the interactions between silica gel and titania gel in the polymer blend could gradually lead to the formation of tiny crystal nuclei with complicated structure that could slowly grow up to form molecular sieves. Quite different from the conventional zeolites that use the acid sites as the catalytically active centers, the oxidative reactivity of the titanium silicalite zeolite was not proportional to its crystallinity and is associated with the oxidative centers of titanium contained in the zeolite.

Trispectrum and correlation dimension analysis of magnetorheological damper in vibration screen

In order to improve the screening efficiency of vibrating screen and make vibration process smooth,a new type of magnetorheological (MR) damper was proposed. The signals of displacement in the vibration process during the test were collected. The trispectrum model of autoregressive (AR) time series was built and the correlation dimension was used to quantify the fractal characteristics during the vibration process. The result shows that,in different working conditions,trispectrum slices are applied to obtaining the information of non-Gaussian,nonlinear amplitude?frequency characteristics of the signal. Besides,there is correlation between the correlation dimension of vibration signal and trispectrum slices,which is very important to select the optimum working parameters of the MR damper and vibrating screen. And in the experimental conditions,it is found that when the working current of MR damper is 2 A and the rotation speed of vibration motor is 800 r/min,the vibration screen reaches its maximum screening efficiency.

Automatic GUI Test by Using SIFT Matching

In software development process, the last step is usually the Graphic User In- terface（GUI） test, which is part of the final user experience （UE） test. Traditionally, there exist some GUI test tools in the market, such as Abbot Java GUI Test Framework and Pounder, in which testers pre-configure in the script all desired actions and instructions for the computer, nonetheless requiring too much of invariance of GUI environment; and they require reconfiguration in case of GUI changes, therefore still to be done mostly manually and hard for non-programmer testers to. Consequently, we proposed GUI tests by image recognition to automate the last process; we managed to innovate upon current algorithms such as SIFT and Random Fern, from which we develop the new algorithm scheme retrieving most efficient feature and dispelling inefficient part of each algorithm. Computers then apply the algorithm, to search for target patterns themselves and take subsequent actions such as manual mouse, keyboard and screen I/O automatically to test the GUI without any manual instructions. Test results showed that the proposed approach can accelerate GU! test largely compared to current benchmarks.