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Dynamic light scattering (DLS) technology is a powerful approach for measuring ultrafine particle size. The correlation method and photon correlation spectroscopy (PCS) are two methods of DLS technology. However, measurement accuracy of the correlation method and PCS based on traditional power spectrum is lower under the condition of the small amount of measurement data. For measurement problem of the small amount of data, PCS based on auto-regressive (AR) power spectrum is proposed in this paper. According to existing small amount of measurement data, this method can forecast subsequent data by an AR model, and then estimate the power spectrum of the data, which can achieve the measurement accuracy of the large amount of data. Besides, the optimal fast Fourier transform (FFT) points of 50 nm–1000 nm particles are obtained by analyzing the mean square error (MSE) of the AR power spectrum and its theoretical power spectrum in different FFT points. The results of simulation and experiment data demonstrate that the AR power spectrum method might serve as an effective approach to PCS measurement problem with the small amount of data.

The temperature controller is an important part of the control system design of the crude oil heating furnace. the traditional PID control is usually used in temperature control, but it can not effectively overcome the impact by the interference, load change and the parameters change of system and other factors. Based on the relationship between rules factor α and the error E , meanwhile, taking into account the change of error r rate E C, the temperature controller is designed adaptive fuzzy control with variable slope. It greatly enhances the robustness of the system. By field application, works well.

For ill-posed inversion problem of dynamic light scattering (DLS), this paper is discusses DLS inversion of GMRES algorithm. Combining Tikhonov regularization inversion strategy with GMRES algorithm, a GMRES-TIK inversion algorithm is designed in this paper. The simulation datum was respectively inversed by two methods. The inversion results demonstrate that, correct inversion results can’t obtained by GMRES algorithm, however inversion results of GMRES-TIK algorithm is reasonable under a certain noise level. Therefore, we can draw conclusions that GMRES algorithm can’t directly used for DLS inversion, after combining Tikhonov regularization method, it can used for DLS inversion and has strong noise immunity.

Photon Correlation Spectroscopy (PCS) is a powerful technique for the sizing of particle size distribution (PSD). It is an ill-posed inversion problem. According to actual situation, PSD is non-negative. In order to inverse desired PSD, during the inversion process, non-negative condition should is imposed for inversion problem. This paper proposes a regularization inversion method based on interior-point algorithm for PSD constraint. This method changes constrained optimization problems into unconstrained optimization problem. The simulation data of unimodal distribution particles were inversed by this method. The results demonstrate this method is feasible for PCS inversion.

Computer simulation is a more convenient and faster method obtaining photon correlation spectroscopy (PCS) signal. Based on orthogonal inverse wavelet transform (OIWT), a new simulation method is developed. This method considers that PCS signal of a single scale is composed of several sub-band signals with different characteristic. According to the relationship of power spectrum of PCS signal and orthogonal wavelet coefficients of every scale, using OIWT, PCS signal can be obtained by simulation of several different sub-band signals. Using this method, PCS signals of 90nm, 600nm and1000nm are respectively simulated. Mean square errors of the power spectrums of the simulation signals and their theoretical power spectrums are e-5 order of magnitude. The relative errors of particle size inverted from simulation signals are less than 2.47%. Comparison of simulation and experiment proves that that OIWT is feasible for simulation of PCS signal. In addition, by analyzing the influence of simulation parameters on simulation accuracy, we get relationship of particle size, decomposition scale and sampling frequency. DOI: http://dx.doi.org/10.11591/telkomnika.v11i11.3487

In order to make the student easily understand the image processing theory and combine theory teaching with practical teaching of this technology, it is very important to develop a set of software suitable for teaching. This paper discusses image processing technique based on Visual Basic (VB) and a set of teaching software of digital image processing is developed by this technique. This software can successfully realize some image processing algorithm and has the features with easy operability, beautiful user interface and good vision. Practice demonstrates that the effect of teaching is improved by this software. The practical application ability of students is enhanced and the teaching target of combining theory with practice is achieved by this software. At the same time, learning interest of student is also increased.

In order to increase the robustness of the crude oil heating furnace system, the rule self-adaptive fuzzy control of entire domain is generally used for temperature control of system. However, when the parameter is adjusted, this algorithm doesn't consider the effect of the rate of error change (EC). Therefore, this paper use the varied slope rule self adaptive fuzzy control algorithm for temperature control of crude oil heating furnace. When the error is adjusted, the curve slope of this method is also adjusted with the. Response results of actual heating furnace datum show that this control algorithm can enhance the dynamic and static trait of system. It demonstrates that this method is feasible for temperature control of crude oil heating furnace.

In traditional double exponential inversion algorithm of photon correlation spectroscopy (PCS), four initial parameters choice of decay linewidths and decay linewidth distribution coefficients affect the particles size inversion accuracy. In order to obtain the optimal parameters, based on differential evolution algorithm, an optimization algorithm within the global is proposed. This algorithm begin from a solution set of four parameters, iteratively calculated by operation rules of differential, variation and choice, simultaneously perform survival of the fittest according to the objective function value of each solution and gradually guide the search process approaching the optimal solution. This algorithm overcomes difficult of iterative initial value choice By new algorithm and traditional algorithm, simulation datum with noise-free and noise of 100nm-500nm bi-dispersed particles were respectively inversed. The results show new algorithm has strong tolerance of noises, when the noise levels is within 0~0.001,compared with tradition algorithm, it can reduce inversion error by 0.31% ∼ 2.52%. Therefore, new algorithm is effective double exponential inversion algorithm in particles size inversion of PCS.

In order to make the student easily understand the particles measurement principles of microscope image and cooperate with the theory teaching and practical teaching of this technology. A set of software design which set theory teaching and practical teaching in one is given. This particles measurement software was designed by GUI of MATLAB. It can successfully calculate the size and number of particles by some image process. The software has the features with easy operability, friendly user interface. Practice demonstrates that the effect of teaching is improved, the quality of software program and the practical application ability of students are enhanced, and the teaching target of combining theory with practice is achieved by this software. At the same time, learning interest of student is also increased.

In order to easily realize real-time computing power of multimedia courseware of PowerPoint, a multimedia courseware design method of is presented. This method designs the courseware based on the technology combining PowerPoint and MATLAB. This technology can realize data exchange of PowerPoint and MATLAB by ActiveX automation. By this technology, data of PowerPoint can sent to MATLAB workspace, complex calculation is completed by MATLAB, and then calculated data sent back PowerPoint again. Practice demonstrates that multimedia courseware designed by this technology has real-time computing power, friendly user interface, good interaction and its programming is very simple.

Tikhonov regularization is an effective way in particles size inversion of dynamic light scattering (DLS). Regularization parameter choice is the key in this approach. In order to obtain the optimal regularization parameter, according to the Morozov discrepancy principle, an regularization inversion method based on genetic algorithms (GA)is proposed. It optimizes the regularization parameter within the global region by genetic algorithms, does not require a priori particle size distribution (PSD) and doesn't also define the initial value of the regularization parameter. Computer simulations datum of particles were respectively inversed by this method. The results show that when the noise level is 0∼0.001, results of unimodal distribution particles agree with the theory distribution, and double-peak feature of bimodal distribution particles is clear, maximum error of theirs inversion peak value is less than 6.67%. Therefore, regularization inversion method with GA technique has strong immunity of noises and is feasible in particles size inversion of DLS.