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1

Oil-assisted flotation of fine hematite using sodium oleate or hydroxamic acids as a collector

Li H., Liu M., Liu Q.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 4

1130--1145

EN

Micro-flotation and batch flotation tests were carried out on fine (-20 µm) hematite to investigate the influences of non-polar oil when sodium oleate, octyl hydroxamic acid, or oleoyl hydroxamic acid was used as a collector. Both micro-flotation and batch flotation tests were performed using single hematite mineral and/or artificial mixed minerals (hematite:quartz = 1:1), and kerosene was utilized as the neutral oil. The experimental results showed that the addition of a kerosene emulsion benefited hematite recovery in the micro-flotation tests where a froth layer did not exist. In the batch flotation where a froth layer existed, kerosene behaved differently when used in conjunction with the three collectors. Kerosene helped improve the batch flotation when sodium oleate or oleoyl hydroxamic acid was used as a collector. However, it reduced concentrate weight yield, grade and recovery to a noticeable extent when octyl hydroxamic acid was used as a collector, especially at low dosages. In addition, single hematite batch flotation kinetics tests coupled with water recovery measurement were carried out to study the role of kerosene at different collector dosages. It was observed that water drainage and the resulting froth destabilization by kerosene was dominant at low collector dosages, especially in the flotation using octyl hydroxamic acid. At higher collector dosages, the water drainage and froth destabilization effect by kerosene was possibly counter-balanced by the higher hematite surface hydrophobicity and bubble surface tension gradient, which led to more stable froth layer.

2

Reconstruction algorithm for obtaining the bending deformation of the base of heavy-duty machine tool using inverse Finite Element Method

Liu M., Zhang X., Song H., Wang J., Zhou S.

Metrology and Measurement Systems

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2018

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Vol. 25, nr 4

727--741

EN

The field of mechanical manufacturing is becoming more and more demanding on machining accuracy. It is essential to monitor and compensate the deformation of structural parts of a heavy-duty machine tool. The deformation of the base of a heavy-duty machine tool is an important factor that affects machining accuracy. The base is statically indeterminate and complex in load. It is difficult to reconstruct deformation by traditional methods. A reconstruction algorithm for determining bending deformation of the base of a heavy-duty machine tool using inverse Finite Element Method (iFEM) is presented. The base is equivalent to a multi-span beam which is divided into beam elements with support points as nodes. The deflection polynomial order of each element is analysed. According to the boundary conditions, the deformation compatibility conditions and the strain data measured by Fiber Bragg Grating (FBG), the deflection polynomial coefficients of a beam element are determined. Using the coordinate transformation, the deflection equation of the base is obtained. Both numerical verification and experiment were carried out. The deflection obtained by the reconstruction algorithm using iFEM and the actual deflection measured by laser displacement sensors were compared. The accuracy of the reconstruction algorithm is verified.

3

Three-dimensional simulation of the fracture system distribution in formation rock based on fractal method

Li W., Zhao H., Liu M., Li S., Sun W., Wang L.

Archives of Mining Sciences

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2018

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Vol. 63, no. 2

425--436

EN

During exploitation process of fractured reservoir, the complex distribution of natural fracture system may lead to a series of accidents, such as sand plug and multi fracture extension in hydraulic fracturing operation. Considering the difficulties of numerical analysis on formation rock mass fracture system distribution, three-dimensional geometry model of a single fracture formation is proposed in this paper, and fractal geometry method is introduced to build the three-dimensional fractal description model of formation fracture system distribution. On this basis, the effects of fractal parameters on natural fracture porosity, permeability and other properties are analyzed. The results show that: First, the number and propagation of natural fracture are controlled by the fractal dimension, the number of groups and the initial quantity. Second, the fractal dimension of natural fracture distribution has an obvious effect on natural fracture porosity and permeability. Third, porosity and permeability of natural fracture distribution both experience exponential growth as fractal dimension increases. Fourth, when the fractal dimension remains constant, the porosity and permeability of natural fractures both increase with the fracture scale.

PL

W trakcie eksploatacji złoża zalęgającego w spękanych warstwach i pokładach złożony system naturalnych spękań prowadzić może do licznych incydentów, np. powstawania zatorów piaskowych lub nadmiernego rozszerzenia spękań w trakcie szczelinowania hydraulicznego. Z uwagi na trudności związane z analizą numeryczną rozkładu spękań skał macierzystych, w pracy zaproponowano trójwymiarowy model geometryczny pojedynczego pęknięcia z wykorzystaniem metod geometrii fraktalnej do opracowania trójwymiarowego modelu opisującego powstawanie układu spękań i ich rozkład. Na tej podstawie przeanalizowano wpływ parametrów fraktalnych na naturalną porowatość pękniętych skał, ich przepuszczalność oraz pozostałe właściwości. Wyniki badań wskazują że, po pierwsze, liczba i tempo propagacji naturalnych spękań uzależnione są od wymiarów fraktalnych, liczby grup i wielkości początkowej. Po drugie, wymiary fraktalne naturalnego systemu spękań skał mają zdecydowany wpływ na porowatość i przepuszczalność. Po trzecie, porowatość i przepuszczalność naturalnych systemów pęknięć wykazują wzrost w miarę wzrastania wymiarów fraktalnych. Po czwarte, gdy wymiary fraktalne pozostają niezmienne, zarówno porowatość i przepuszczalność naturalnych spękań rosną wraz ze skalą fraktali.

4

Effect of Strain Rate on the Microstructure of Warm-Deformed Ultrafined Medium-Carbon Steel

Yuan Q., Xu G., Liu S., Liu M., Hu H.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 4

1805--1813

EN

In this study, medium-carbon steel was subjected to warm deformation experiments on a Gleeble 3500 thermosimulator machine at temperatures of 550°C and 650°C and strain rates of 0.001 s-1 to 1 s-1. The warm deformation behavior of martensite and the effects of strain rate on the microstructure of ultrafine grained medium-carbon steel were investigated. The precipitation behavior of Fe3C during deformation was analyzed and the results showed that recrystallization occurred at a low strain rate. The average ultrafine ferrite grains of 500 ± 58 nm were fabricated at 550°C and a strain rate of 0.001 s-1. In addition, the size of Fe3C particles in the ferrite grains did not show any apparent change, while that of the Fe3C particles at the grain boundaries was mainly affected by the deformation temperature. The size of Fe3C particles increased with the increasing deformation temperature, while the strain rate had no significant effect on Fe3C particles. Moreover, the grain size of recrystallized ferrite decreased with an increase in the strain rate. The effects of the strain rate on the grain size of recrystallized ferrite depended on the deformation temperature and the strain rate had a prominent effect on the grain size at 550°C deformation temperature. Finally, the deformation resistance apparently decreased at 550°C and strain rate of 1 s-1 due to the maximum adiabatic heating in the material.

5

Nonlinear PTO effect on performance of vertical axisymmetric wave energy converter using semi-analytical method

Liu M., Liu H., Zheng X., Chen H., Wang L., Zhang L.

Polish Maritime Research

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2017

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S 3

49--57

EN

The wave energy, as a clean and non-pollution renewable energy sources, has become a hot research topic at home and abroad and is likely to become a new industry in the future. In this article, to effectively extract and maximize the energy from ocean waves, a vertical axisymmetric wave energy converter (WEC) was presented according to investigating of the advantages and disadvantages of the current WEC. The linear and quadratic equations in frequency-domain for the reactive controlled single-point converter property under regular waves condition are proposed for an efficient power take-off (PTO). A method of damping coefficients, theoretical added mass and exciting force are calculated with the analytical method which is in use of the series expansion of eigen functions. The loads of optimal reactive and resistive, the amplitudes of corresponding oscillation, and the width ratios of energy capture are determined approximately and discussed in numerical results.

6

Vibrator Data Denoising Based on Fractional Wavelet Transform

Zheng J., Zhu G., Liu M.

Acta Geophysica

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2015

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Vol. 63, no. 3

776--788

EN

In this paper, a novel data denoising method is proposed for seismic exploration with a vibrator which produces a chirp-like signal. The method is based on fractional wavelet transform (FRWT), which is similar to the fractional Fourier transform (FRFT). It can represent signals in the fractional domain, and has the advantages of multi-resolution analysis as the wavelet transform (WT). The fractional wavelet transform can process the reflective chirp signal as pulse seismic signal and decompose it into multi-resolution domain to denoise. Compared with other methods, FRWT can offer wavelet transform for signal analysis in the timefractional- frequency plane which is suitable for processing vibratory seismic data. It can not only achieve better denoising performance, but also improve the quality and continuity of the reflection syncphase axis.

7

Chromatographic Fingerprint Analysis and Characterization of Constituents in Shenqi Fuzheng Injection by HPLC-DAD-ELSD and UFLC-DAD-Q-TOF Tandem Mass Spectrometry Techniques

Wang J., Liu M., Tong X., Peng W., Cao H., Su W.

Acta Chromatographica

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2015

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Vol. 27, no. 3

551--569

EN

Shenqi Fuzheng Injection (SFI) is a traditional Chinese medicine injection, widely used to enhance immune function of clinical cancer patients undergoing chemotherapy. In this study, a high-performance liquid chromatography-diode array detection-evaporative light scattering detection (HPLC-DAD-ELSD) method was established for quality control of SFI, which could simultaneously semiquantitatively reflect the constituents displayed in the chromatographic profile of SFI. The relative retention time and relative peak areas of the 21 common peaks related to the reference peak were calculated. The validity and advantage of this method were validated by systematically comparing chromatograms of 10 batches of SFI samples with the analytical methods of principal component analysis and angle cosine method recommended by the State Food and Drug Administration of China. Moreover, a total of 21 constituents of SFI were identified or tentatively characterized in the fingerprint via ultrafast liquid chromatography-diode array detection-quadrupole time-of-flight (UFLC-DAD-Q-TOF) tandem mass spectrometry technique on the basis of the retention time, ultraviolet spectra, fragmentation patterns, and reported literatures. All the results proved that the technique was useful in comprehensive quality evaluation of SFI and further study.

8

Initial effects of experimental warming on temperatore,moisture and vegetation characteristics in an alpine meadow on the Qinghaj-Tibetan Plateau

Xu M.-H., Peng F., You Q.-G., Guo J., Tian X.-F., Liu M., Xue X.

Polish Journal of Ecology

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2014

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Vol. 62, nr 3

491--509

EN

The ongoing warming in the Qinghai-Tibetan Plateau leads to changes in ecosystem processes while the responses of soil and vegetation are not well understand. Thus, we used infrared radiators to carry out experimental warming from July 2010 to August 2011 in an alpine meadow on the Plateau (about 4630 m above sea level) to research the responses of environmental factors and vegetation characteristics to short-term warming (1 year). The experimental design was a block design consisting of five replications and included three treatment levels: control, T1 (130 W m-2) and T2 (150 W m-2). The results showed that air temperature at 20 cm height, surface temperature and soil temperature in the 0–100 cm layers increased with warming. The biggest differences of T1 (1.66°C) and T2 (2.34 °C) appeared on the surface and at 20 cm depth, whereas the biggest amplitudes of T1 (27.15%) and T2 (35.81%) all occurred at 100 cm depth. Soil moisture showed different trends with warming in different soil layers. In the 0–40 cm layers, soil moisture decreased with warming. The biggest differences (–2.97% for T1 and –2.73% for T2) and amplitudes (–18.07% for T1 and –16.64% for T2) all appeared at 10 cm depth. In the 60–100 cm layers, soil moisture increased with warming. The biggest differences (2.53% for T1 and 6.45% for T2) and amplitudes (11.39% for T1 and 29.05% for T2) all occurred at 100 cm depth. Relative to control, vegetation height and aboveground biomass increased significantly in T1 and T2 (P <0.05), while vegetation coverage had not significant differences in T1 and T2 (P> 0.05). In T1 and T2, the amplitudes were 30.67% and 30.19% for vegetation height, and 36.22% and 27.87% for vegetation aboveground biomass, and 12.89% and 4.42% for vegetation coverage, respectively. In the path analysis between environment and vegetation properties, vegetation was directly affected by soil moisture at 40 cm and 60 cm depths, whereas indirectly influenced by relative humidity at 20 cm height and soil temperature at 40 cm depth. This might be related to the downward movement of the soil moisture caused by warming.

9

Automatic calibration system for digital-display vibrometers based on machine vision

He W., Xu G., Rong Z., Li G., Liu M.

Metrology and Measurement Systems

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2014

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Vol. 21, nr 2

317--328

EN

Considering the low efficiency during the process of traditional calibration for digital-display vibrometers, an automatic calibration system for vibrometers based on machine vision is developed. First, an automatic vibration control system is established on the basis of a personal computer, and the output of a vibration exciter on which a digital-display vibrometer to be calibrated is installed, is automatically adjusted to vibrate at a preset vibration level and a preset frequency. Then the display of the vibrometer is captured by a digital camera and identified by means of image recognition. According to the vibration level of the exciter measured by a laser interferometer and the recognized display of the vibrometer, the properties of the vibrometer are calculated and output by the computer. Image recognition algorithms for the display of the vibrometer with a high recognition rate are presented, and the recognition for vibrating digits and alternating digits is especially analyzed in detail. Experimental results on the built-up system show that the prposed image recognition methods are very effective and the system could liberate operators from boring and intense calibration work for digital-display vibrometers.

10

Highly efficient organic ultraviolet photodetectors based on excellent Cu(I) complexes

Liu C. B., Su B., Liu M., Zhang X. X., Wang L., Zhang S., Che G. B., Xu Z. L.

Opto-Electronics Review

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2013

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Vol. 21, No. 3

288-292

EN

We demonstrate high response organic ultraviolet photodetectors using 4,4',4''-tris[3-methyl-pheny(phenyl)amino]tri-phenylamine (m-MTDATA) and two novel Cu(I) complexes, [Cu(DPEphos)(PyPhen)]BF (CuDP)(DPEphos = Bis [2-(diphenylphosphino)phenyl]ether, PyPhen = pyrazino[2,3-f][1,10]phenanthroline) and [Cu(DPEbenz)(PyPhen)] BF₄(CuBP) (DPEbenz = 1,2-bis(diphenylphosphino)benzene) to act as the electron donor and acceptor, respectively. Strong photoluminescence quenching of m-MTDATA by Cu(I) complexes is observed manifesting the efficient photoinduced charge transfer that occurs between m-MTDATA and Cu(I) complexes. The optimized photodetector based on CuBP exhibits a maxi-mum response of 276 mA/W at -12 V under an illumination of 365 nm UV light irradiation with an intensity of 1.75 mW/cm². The high response is attributed to feasible energy level match, efficient electron transfer from m-MTDATA to CuBP and skillful device design. More detailed working mechanism of harvesting high performance is also discussed.

11

Vector-based Attribute Reduction Method for Formal Contexts

Shao M., Liu M., Guo L.

Fundamenta Informaticae

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2013

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Vol. 126, nr 4

397--414

EN

Attribute reduction is one basic issue in knowledge discovery of information systems. In this paper, based on the object oriented concept lattice and classical concept lattice, the approach of attribute reduction for formal contexts is investigated. We consider attribute reduction and attribute characteristics from the perspective of linear dependence of vectors. We first introduce the notion of context matrix and the operations of corresponding column vectors, then present some judgment theorems of attribute reduction for formal contexts. Furthermore, we propose a new method to reducing formal context and show corresponding reduction algorithms. Compared with previous reduction approaches which employ discernibility matrix and discernibility function to determine all reducts, the proposed approach is more simpler and easier to implement.

12

The Application of Partial Discharge Detection for the condition assessment of XLPE Power Cables

Zhou X., Qian Y., Liu M.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 6

313-316

EN

Partial discharge (PD) detection is an important means in the condition-based maintenance of high voltage apparatus including crosslinked polyethylene (XLPE) power cables. In this contribution, we introduce the recent work in Shanghai municipal electric power company on the condition-based maintenance of XLPE power cables. As to how to carry out the PD detection in different circumstances, three schemes are laid out in brief. Particularly, a novel idea of partial discharge joint detection method, which is based on multiple sensors, or the high frequency current transformer (HFCT) coupling technique, ultra high frequency (UHF) and acoustics emission (AE) partial discharge detection technique, is proposed. Use more than one kind of coupling techniques, the reliability of onsite PD detection and diagnosis can be improved significantly.

PL

Przedstawiono metody wykorzystania wyładowania niezupełnego do testowania stanu kabli typu XLPE. Wykorzystano różne czujniki, jak np. wysokoczęstotliwościowy transformatorowy czujnik prądu czy czujniki emisji akustycznej.

13

Improved Electrical Measurement Method for Junction Temperature of Light Emitting Diodes

Shen H., Han K., Liu M., Fan S.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 3b

180-184

EN

The electrical test method (ETM) is used to measure the junction temperature Tj of high brightness LEDs. NI 5922 digitizer and Keithley S2400 source meter were used to build the measurement system. Various measurement currents were used under 1MHz sampling rate. Results of different measurement currents are found to be the same under the same sampling rate and measurement error can be found under low sampling rates. When sampling rate is down to 0.2kHz, measurement error is up to 13.7%.

PL

Zaproponowano metodę pomiaru temperatury złącza diody LED. Określono błąd metody dla różnych częstotliwości próbkowania.

14

EMC Requirements and Test Methods for Light Emitting Diodes

Bao X., Fan S., Pan J., Liu M., Liu M., Shen H.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 10a

269-272

EN

EMC test is important for the reliability improvement of LEDs and their application products. This paper introduces the EMC requirements for LED chips, LED devices and LED application products, focusing on electrostatic discharge, electrical fast transient, thunder stroke surge, voltage dip, conductive interference and radio frequency interference. Corresponding test methods are also given. These EMC requirements and test methods are valuable for LED manufacturer and end users.

PL

W artykule przedstawiono wymagania EMC w stosunku do LEDów oraz urządzeń z nimi współpracujących, takich jak wyładowania elektrostatyczne, stany przejściowe, skoki napięcia, interferencje. Przedstawiono odpowiednie metody badawcze. (Wymagania elektrokompatybilności i metody badania układów LED)

15

Study on the driving circuit for LED Taxiway Centreline Light

Zhou X., Jiang X., Qian Y., Liu M.

Przegląd Elektrotechniczny

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2010

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R. 86, nr 9

339-342

EN

Light Emitting Diodes (LEDs) are suitable candidate for using in Taxiway Centreline light due to their inherent advantages such as high efficacy, long life time, and small package. LEDs can not directly replace the traditional halogen lamps used in airport because the power supply in the airport is a specially made AC constant current source. This paper designed a driving circuit for LED taxiway centreline light, which can be dimming, to ensure that LEDs can work stably in airport light.

PL

Diody LED są dobrym kandydatem na światła ostrzegawcze dzięki dużej skuteczności, małym wymiarom i długiej żywotności. Nie zastąpi one świateł halogenowych używanych na lotniskach ponieważ zasilanie na lotniskach jest typu AC. W artykule przedstawiono układ zasilania diod LED umożliwiający zmianę jasności przez co mogą pracować stabilnie w świetle lotniska.

16

Strong convergence theorem of a hybrid projection algorithm for a family of quasi-φ-asymptotically nonexpansive mappings

Tang J. F., Chang S. S., Liu M., Liu J. A.

Opuscula Mathematica

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2010

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Vol. 30, no. 3

341-348

EN

The main purpose of this paper is by using a new hybrid projection iterative algorithm to prove some strong convergence theorems for a family of quasi-φ-asymptotically nonexpansive mappings. The results presented in the paper improve and extend the corresponding results announced by some authors.

17

Dehydration-Induced Charge Transfer in Ni3[Fe(CN)6]2ź15H2Oe T

Liu M., Bian X. F., Xia Y. F., Bao Z., Xu M. X.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 10

1729-1735

EN

Molecular magnet nickel(II) hexacyanoferrate(III), powder Ni3[Fe(CN)6]2ź15H2O, was prepared by coprecipitation method. The coprecipitated powder was annealed in vacuum at different temperatures of 80, 100, 120, and 140 graduate C. Water molecules contained in Prussian blue analogues were removed by heating. The effects of dehydration on its charge transfer properties were studied by Fourier-transform infrared and Mössbauer measurements. It was found that the FeIII–CN–NiII state is the major structure in the coprecipitated form, while the FeII–CN–NiIII bond is formed in the annealed samples. The dehydration of NiII ferricyanide above 80°C induces an inner charge transfer from NiII towards FeIII to form the mixed valence system Ni(II) Ni(III) ferri-ferro-cyanide.

18

Fast leak detection and location of gas pipelines based on an adaptive particle filter

Liu M., Zang S., Zhou D.

International Journal of Applied Mathematics and Computer Science

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2005

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Vol. 15, no 4

541-550

EN

Leak detection and location play an important role in the management of a pipeline system. Some model-based methods, such as those based on the extended Kalman filter (EKF) or based on the strong tracking filter (STF), have been presented to solve this problem. But these methods need the nonlinear pipeline model to be linearized. Unfortunately, linearized transformations are only reliable if error propagation can be well approximated by a linear function, and this condition does not hold for a gas pipeline model. This will deteriorate the speed and accuracy of the detection and location. Particle filters are sequential Monte Carlo methods based on point mass (or “particle”) representations of probability densities, which can be applied to estimate states in nonlinear and non-Gaussian systems without linearization. Parameter estimation methods are widely used in fault detection and diagnosis (FDD), and have been applied to pipeline leak detection and location. However, the standard particle filter algorithm is not applicable to time-varying parameter estimation. To solve this problem, artificial noise has to be added to the parameters, but its variance is difficult to determine. In this paper, we propose an adaptive particle filter algorithm, in which the variance of the artificial noise can be adjusted adaptively. This method is applied to leak detection and location of gas pipelines. Simulation results show that fast and accurate leak detection and location can be achieved using this improved particle filter.

19

0.2-kJ and 2-kJ high rep rate Dense Plasma foci : their design, technology, and applications

Dubrovsky A. V., Gribkov V. A., Ivanov Y. P., Lee P., Lee S., Liu M., Samarin V. A.

Nukleonika

|

2001

|

Vol. 46, suppl. 1

107--111

EN

The paper presents various designs of several medium and small size Dense Plasma Focus (DPF) chambers intended for numerous applications, a description of technologies used in these facilities, and some results reached with these devices by using a number of diagnostic techniques. In present experiments the DP foci have been used mainly as an X-ray source. We discuss here how it is possible to satisfy absolutely new and very strict demands on the construction and technology for the devices to be eventually applied in science and industry. Between these characteristics there are a high repetition rate (typically 1…15 Hz) and a long lifetime (over 1 million shots). Their switching elements, a collector and chambers must withstand a high quasi-continuous heat load (up to 100 kW). High energy density in the central part of the chamber anode and the necessity to provide a channel for radiation extraction demanded a special construction and specific materials implementation in this region. Their X-ray spectrum should be tuned. They have to operate with different working gases and preferably in a wide range of pressures. All these points are discussed in this report. Capabilities of the described techniques are illustrated by results of the recent experimental studies carried out with facilities located at the Nanyang Technological University (NX1) as well as at the Lebedev Physical Institute (PF-0.2).