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1

One step purification of impurities in the leachate of weathered crust elution-deposited rare earth ores

Zhou F., Feng J., Wang Z., Xu Y., Zhang Z., Chi R.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

1188--1199

EN

It is necessary to control and reduce the high content of Al3+, Cu2+ and Pb2+ ions in the leachate of weathered crust elution-deposited rare earth ore to facilitate the rare earth recovery and the quality of rare earth products. Neither NH4HCO3 nor Na2S are suitable for removal of all impurity ions and meanwhile maintain high rare earth recovery. Conventionally, NH4HCO3 is firstly adopted to remove Al3+, and then Cu2+ and Pb2+ are removed by using Na2S. This two steps purification process is quite long and results in lots of complication in operation. In this paper, a one-step purification by using the compound of NH4HCO3 and Na2S was proposed to remove Al3+, Cu2+ and Pb2+. The results showed that after purification 89% Cu, 92% Pb and 74% Al were removed from the leachate solution by using 0.1 M compound of NH4HCO3/Na2S, while maintaining 89% rare earth. The optimal purification parameters were: volume ratio of NH4HCO3 to Na2S of 9:1, volume ratio of compound to leachate of 0.05:1, precipitation time of 30 min.

2

Double-layer microwave absorber based on nanocrystalline CoFe2O4 and CoFe2O4/PANI multi-core/shell composites

Xu Y., Shen G., Wu H., Liu B., Fang X., Zhang D., Zhu J.

Materials Science Poland

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2017

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Vol. 35, No. 1

94--104

EN

Organic-inorganic nano-CoFe2O4/PANI (polyaniline) multi-core/shell composites have been successfully synthesized by chemical oxidative polymerization of aniline. The characterization results showed that the ferrite nanocrystals were efficiently embedded in PANI. The electromagnetic parameters of the composites were measured by a vector network analyser in the frequency range of 2 GHz to 18 GHz. Double-layer absorbers based on the CoFe2O4/PANI composite (matching layer) and calcined CoFe2O4 ferrite (absorbing layer) have been designed. The reflection loss of the microwave absorbers of both single layer and double-layer with a total thickness of 2.0 mm and 2.5 mm was calculated according to transmission-line theory. The results indicated that the minimum reflection loss of the CoFe2O4/PANI composite was −19.0 dB at 16.2 GHz at the thickness of 2.0 mm and −23.6 dB at 13.1 GHz at the thickness of 2.5 mm, respectively. The minimum reflection loss for double-layer absorbers reached −28.8 dB at 16.2 GHz at the total thickness of 2.0 mm, and −31.1 dB at 12.8 GHz at the total thickness of 2.5 mm. The absorption bandwidth under −10 dB was 4.2 GHz (13.8 GHz to 18.0 GHz) and 5.5 GHz (10.3 GHz to 15.8 GHz), respectively. The results show that the reflection loss and absorption bandwidth of the double-layer absorbers are obviously enhanced compared to corresponding single layer absorbers.

3

Comparative analysis of three ionospheric broadcast models for global navigation satellite systems

Li S., Li L., Wang S., Peng J., Xu Y., Zhao Y.

Acta Geophysica

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2017

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Vol. 65, no. 2

395--410

EN

An ionospheric model and corresponding coefficients broadcasted via GNSS navigation message are generally used to estimate the time delay for single-frequency GNSS users. In this article, the capabilities of three ionospheric models, namely, Klobuchar model, NeQuick Galileo version (NeQuick G), and Neustrelitz TEC broadcast model (NTCM-BC), were assessed. The models were examined in two aspects: total electron content (TEC) prediction and ionospheric delay correction effects in single-point positioning. Results show that both NeQuick G and NTCM-BC models outperformed Klobuchar model for predicting global TEC values during all the test days. Compared with Slant TEC (STEC) along the receiver-to-satellite ray path derived from IGS global ionosphere map (GIMs), STEC from NeQuick G and NTCM-BC models tend to have less bias than those from Klobuchar model in most situations. The point positioning results were improved by applying ionospheric broadcast models especially at the mid- and low-latitude stations.

4

Simultaneous measurement of refractive index and thickness for optically transparent object with a dual-wavelength quantitative technique

Xu X., Wang Y., Xu Y., Jin W.

Optica Applicata

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2016

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Vol. 46, nr 4

597--605

EN

We present a new dual-wavelength quantitative measurement approach that can be employed for simultaneously measuring both the refractive index and the thickness of the homogenous specimen. This method is realized by dual-wavelength in-line phase-shifting digital holography, and then the phase images are obtained by using four-phase step algorithm for each wavelength separately. Based on computer simulation technology, the feasibility and the effectiveness of our proposed method are demonstrated by comparing our simulation results with the experimental results of the spherical silica bead and the red blood cell, respectively. Our work will provide some guidance in the experimental research for transparent phase objects.

5

A New Graph Theoretic Approach for Protein Threading

Song Y., Qu J., Xu Y., Cai L.

Fundamenta Informaticae

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2016

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Vol. 145, nr 2

151--170

EN

In this paper, we develop a novel graph theoretic approach for protein threading. In order to perform the protein sequence-structure alignment in threading both efficiently and accurately, we develop a graph model to describe the tertiary structure of a protein family and the alignment between a sequence and a family can be efficiently computed with a dynamic programming algorithm when the tree width of the graph model is a small integer. Our experiments show that this new approach is significantly faster than existing tools for threading and can achieve comparable prediction accuracy.

6

Dynamic Characteristic Analysis of the Needle Multi-linkage Mechanism in a Carpet Tufting Machine’s Driving System

Xu Y., Sun Z., Huang S., Sheng X., Chi X.

Fibres & Textiles in Eastern Europe

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2016

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Vol. 24, no. 3 (117)

103--109

EN

In a typical carpet tufting machine, kinematic and dynamic characteristics of the needle multi-linkage mechanism are the important factors affecting the quality of the tufting carpet. For providing a rational basis for mechanism design and vibration characteristic analysis, a mathematical model of the needle multi-linkage mechanism is constructed using the complex vector analysis method. On the basis of the model, kinematic characteristic curves and dynamic characteristic curves of the needle multi-linkage mechanism are analyzed by simulation methods. Finally experimental validation of the alternating load dynamic characteristics is performed on the needle multi-linkage mechanism in a typical carpet tufting machine. The results prove the theoretical analysis validity of the needle multi-linkage mechanism.

PL

W typowej maszynie wiążącej dywany charakterystyki kinematyczne i dynamiczne mechanizmu napędzającego układ igieł są bardzo ważnym czynnikiem określającym jakość wytwarzanych dywanów. Dla otrzymania racjonalnej podstawy dla projektowania mechanizmu i analizy charakterystyk wibracyjnych opracowano matematyczny model mechanizmu napędzającego igły. Przy opracowaniu modelu zastosowano metodę kompleksowej analizy wektorowej. Posłużyło to do otrzymania kinematycznych i dynamicznych krzywych przebiegu. Przebiegi te analizowano za pomocą metod symulacji. Następnie oceniono wyniki eksperymentalnie stosując typową maszynę do wytwarzania dywanów. Wyniki potwierdziły prawidłowość przyjętych teoretycznie zależności.

7

Dynamic Garment Simulation based on Hybrid Bounding Volume Hierarchy

Zhu D., Li Z., Xia F., Xu Y.

Autex Research Journal

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2016

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Vol. 16, no. 4

241--249

EN

In order to solve the computing speed and efficiency problem of existing dynamic clothing simulation, this paper presents a dynamic garment simulation based on a hybrid bounding volume hierarchy. It firstly uses MCASG graph theory to do the primary segmentation for a given three-dimensional human body model. And then it applies K-means cluster to do the secondary segmentation to collect the human body’s upper arms, lower arms, upper legs, lower legs, trunk, hip and woman’s chest as the elementary units of dynamic clothing simulation. According to different shapes of these elementary units, it chooses the closest and most efficient hybrid bounding box to specify these units, such as cylinder bounding box and elliptic cylinder bounding box. During the process of constructing these bounding boxes, it uses the least squares method and slices of the human body to get the related parameters. This approach makes it possible to use the least amount of bounding boxes to create close collision detection regions for the appearance of the human body. A spring-mass model based on a triangular mesh of the clothing model is finally constructed for dynamic simulation. The simulation result shows the feasibility and superiority of the method described.

8

3D morphological reconstruction of the red blood cell based on two phase images

Wang Y, Li Z, Ji Y, Xu Y, Bu M

Optica Applicata

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2015

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Vol. 45, nr 2

173--182

EN

As an important component of blood cells, the red blood cell plays a vital role in many diseases such as malaria and so on. Although quantitative phase imaging techniques can be used for homogeneous cellular thickness distribution to obtain ideal results, they cannot achieve 3D morphological distribution. In this paper, a new method is presented to get a 3D morphology image of red blood cell. With this method, only two cellular quantitative phase images obtained from two orthogonal directions are needed as original information. By using the grid method, the sample is divided into many small phase cubes, and then we take a layer’s cubes into calculation so that the 3D problem could be transformed into a 2D problem to elaborate. Then it can be applied to the tomographic imaging combined with the maximum entropy method according to the two orthogonal phase images. This method has been proved by a simulation of red blood cell. The results show that cellular morphological distribution can be achieved in detail very well just based on only two orthogonal phase images.

9

Surface instability of a semi-infinite isotropic laminated plate under surface van der Waals forces

Wang X., Xu Y., Zhou K.

Archives of Mechanics

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2015

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Vol. 67, nr 2

137--155

EN

By means of complex variable method, the present work demonstrates that the surface of a semi-infinite isotropic laminated plate that is being attracted to a rigid contactor through van der Waals forces is always unstable. Two distinct surface instability modes are identified, and their wavenumbers and wavelengths are presented in concise and simple expressions. Furthermore, the two wavenumbers and wavelengths are completely determined by three elastic parameters of the laminated plate, three parameters related to the interactions between the surface and the contactor, and three parameters related to surface energy.

10

Research on Mechanism Analysis and Elimination Method for the Tufted Carpet Stop Mark

Xu Y., Sun Z., Meng Z, Sun Y.

Fibres & Textiles in Eastern Europe

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2014

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Vol. 22, no. 3 (105)

66--72

EN

The tufted carpet stop mark is an important factor affecting carpet final quality. It is closely related to the change in yarn tension caused by the tufting machine being improperly stopped and the yarn creep properties. The purpose of this paper is to develop a reasonable approach to eliminate the tufted carpet stop mark. Focusing on a typical tufting machine, the tufting equipment system and basic working principle of tufted carpet are briefly described. A yarn path flexing model which integrates yarn feeding parts, yarn guiders and the tufting needle for a typical tufting process is constructed. The yarn tension change is analysed along with the change in the yarn path. A Polypropylene yarn four-component model is used for analysing the relationship between tension and yarn creep properties. The creep property of polypropylene yarn under a certain tension is verified by experiments. According to the yarn tension change in different running positions of the tufting needle, a reasonable method of eliminating the stop mark which stops and restarts the machine in the highest position is put forward. Finally the experimental results prove that the method is effective and feasible.

PL

Ślady zatrzymania pracy maszyn wiążących dywany są ważnym czynnikiem wpływającym na jakość produktu końcowego. Jest to ściśle związane ze zmianą w naprężeniu przędzy spowodowanym przez maszynę wiążącą nieodpowiednio zatrzymaną oraz właściwości pełzania przędzy. Celem pracy było opracowanie metody pozwalającej wyeliminowanie tego zjawiska. W pracy rozważono typową maszynę wiążącą, system wiązania i zasady wiązania dywanów. Opracowano model drogi włókna integrujący elementy prowadzące oraz igły wiążące dla przedstawienia typowego procesu wiązania. Analizowano zmiany naprężenia przędzy wzdłuż jej drogi. Dla przędzy polipropylenowej zastosowano czteroskładnikowy model pozwalający na analizę zależności pomiędzy naprężeniem i pełzaniem przędzy. Właściwości pełzania przędzy polipropylenowej pod określonym naprężeniem zostały zweryfikowane eksperymentalnie. W efekcie opracowano metodę eliminacji śladów zatrzymania, która pozwoliła na efektywną realizację i została sprawdzona doświadczalnie.

11

Multiple compounds determination and fingerprint analysis of Agrimonia pilosa Ledeb by high-performance liquid chromatography

Wang Y., Yin L., Lv G., Xu Y., Xu L., Qi Y., Zheng L., Peng J.

Acta Chromatographica

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2014

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Vol. 26, no. 1

137--156

EN

In the present paper, a simple and reliable high-performance liquid chromatography-diode array detection (HPLC-DAD) method was developed both for quantitative determination and fingerprint analysis of Agrimonia pilosa Ledeb for quality control. Under the optimized HPLC conditions, seven bioactive compounds including rutin, quercetin-3-rhamnoside, luteoloside, tiliroside, apigenin, kaempferol, and agrimonolide were determined simultaneously. For fingerprint analysis, 11 common peaks were selected as the characteristic peaks to evaluate the similarities of 16 different samples collected from different origins in China. Besides, hierarchical cluster analysis (HCA) was also performed to evaluate the variation of the raw materials. This is the first report of using a simple method for quality control of A. pilosa Ledeb through multi-component determination and chromatographic fingerprint analysis to the best of our knowledge.

12

Research on Hybrid Ray-tracing at 2.4 GHz in Man-Made Forests

Xu Y.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3b

152--155

EN

Since the environment in the forest is relatively complicated and there’s a necessity to avoid the dead zone of signal diffraction when laying wireless sensor in the forest, the integration of SBR and UTD is applied to study the impact of 2.4GHz radio-frequency signal on the path loss characteristics in the forest. This paper achieved the ray location from the receive pint to field point by using back-ray tracing method and computed the response electric field relative to each ray by using UTD. Take the poplar planted forest for instance. The measured value and simulated value were compared, finding good consistency between them, which indicates that SBR and UTD can effectively predict the path loss characteristics in the forest.

PL

W artykule przedstawiono zagadnienie rozprowadzania pola sieci bezprzewodowej w obszarze leśnym. Zastosowane rozwiązania (SBR, UTD) pozwoliły na skuteczną lokalizację i przesył informacji przy zastosowaniu fal 2.4GHz. Wyniki symulacyjne porównano z wynikami pomiarów, przeprowadzonych w lesie topolowym.

13

Phase features of several typical blood cells and their identification without unwrapping

Wang Y., Chen Y, Lü C., Shang X., Xu Y., Wu H., Zhu X., Jin W.

Optica Applicata

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2013

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Vol. 43, nr 3

505--514

EN

The digital holographic phase microscopy (DHPM) technique which has been proposed for cellular morphology and dynamic analysis yielded highly desirable results. However, for nucleated cells (especially white blood cells (WBCs)), their submicroscopic structure has not yet been deconstructed through a phase unwrapping method due to the heterogeneity of an internal phase. By analyzing the phase heterogeneity of subclasses of WBCs, the typical phase models of them are built first in this paper; using the simulation method, the wrapped phase distributions of these models are obtained. However, by optimizing the wrapped phase maps and analyzing the relationships between them and typical blood cells, their features are selected and extracted. Then the models built are sorted out from each other successfully without unwrapping via analyzing these extracted features, which provides a valuable approach and technological base for the classification and identification of blood cells.

14

Two-Echelon Reservoir Inventory Management with Forecast Updates: Perspective from Operations of Multireservoir in Interbasin Water Diversion Projects

Xu Y., Wang L., Chen Z., Xia G., Yang Y.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

84-91

EN

We consider a finite-horizon, periodic-review inventory model with inflow forecasting updates following the martingale model of forecast evolution (MMFE) in multiresevoirs. This model introduces a new method of determining an operating policy in which the policy is based on the dynamic programming (DP) model with a physical equation and a recursive equation. It adequately considers the internal relationship among multireservoirs in inter-basin water diversion projects (IBWDP) and calculates the expected benefits from future operation. The stochastic nature of the inflow is taken into account by considering the correlation between the streamflows of each pair of consecutive time intervals based on MMFE. According to interdependence, the probability of transition from a given state or stage to its succeeding ones can be calculated. Finally, to assess the effectiveness of the policies, the model is compared with other model and is applied to the Chinese South-North Water Diversion project.

PL

Analizowano model okresowej inwentaryzacji wraz z przewidywaniem nawodnienia w systemie wielu rezerwuarów. Wprowadzono programowanie dynamiczne uwzględniające wewnętrzne relacje między rezerwuarami w dywersyjnych projektach wodnych. Model sprawdzono na przykładzie chińskiego projektu systemu wodnego północ-południe.

15

Discussion on digitalization of Paper Fiber

Zhang K., Li Z., Xu Y., Wang S.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 5b

113-115

EN

This paper introduced several testing methods of paper fiber parameters, such as projector method, microscopy method, polarized light method and grating method, and also compared the advantages and disadvantages of these methods. In order to express fiber distribution quantitatively, it put forward the idea of taking integrated multifunctional sensor of detection, judgment, self diagnosis, data processing and adaptive ability to test the distribution of paper fiber. It attempted to get the two-dimensional image of paper fiber distribution by this sensor, then used this image to analyze paper fiber parameters such as quantity, length, thickness, opacity, x-values distribution and y-values distribution, and discussed method of analyzing digitalization of paper fiber.

PL

W artykule opisano szereg metod analizy włókna papieru – głównie metody optyczne. Jak rezultat analizy proponuje się dwuwymiaropwy obraz struktury włókna.

16

Electrodeposition and magnetic properties of ternary Fe-Co-Ni alloy nanowire arrays with high squareness ratio

Fu P., Chen G., Xu Y., Cai P., Wang X. H.

Materials Science Poland

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2012

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Vol. 30, No. 3

259--263

EN

Highly-ordered ternary Fe-Co-Ni alloy nanowire arrays with diameters of about 50 nm have been fabricated by alternating current (AC) electrodeposition into the nanochannels of porous anodic aluminum oxide templates. SEM and TEM results indicate that the alloy nanowires are highly ordered. XRD and HRTEM results show that the ternary FeCoNi alloy nanowires are polycrystalline, with HCP-FCC dual phase structure. Magnetic measurements demonstrate that the ternary alloy nanowire arrays have an obvious magnetic anisotropy with an easy magnetization direction being parallel to the nanowire arrays. Along the easy magnetization direction, the coercivity (H c ) and squareness ratio (S) increase as the annealing temperature increases, and reach a maximum level (H c = 1337 Oe, S = 0.96) at 300 °C.

17

Pilot study on chemical industrial wastewater in tertiary treatment with biofilm for washing belts

Liu J.-M., Xu Y., Zhu Z.-R., Qiao S.-Y.

Environment Protection Engineering

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2011

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Vol. 37, nr 1

93-104

EN

The biochemical characteristics of chemical secondary effluent of the wastewater treatment plant of Jilin Chemical Industry Corporation have higher residual concentration of CODcr and NH3-N, and lower residual concentration of BOD5 and alkalinity. These biochemical characteristics of chemical secondary effluent in tertiary treatment were studied with a pilot system of biological contact aerators (BCAs) to meet national discharged limits and requirements for washing belts, particularly to meet national limits of ammonia and benzene substances, etc. in the air of a workshop. The highest removal efficiency was obtained in the BCAs system and a scientific basis of reference was provided for reforming the system of pulse flocculated clarifier which can constitute a new approach in tertiary wastewater treatment for washing belts.

18

Synthesis and characterization of V2O3 microcrystal particles controlled by thermodynamic parameters

Qi J., Ning G., Zhao Y., Tian M., Xu Y., Hai H.

Materials Science Poland

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2010

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Vol. 28, No. 2

535--543

EN

A facile process is developed for the synthesis of pure vanadium(III) oxide by thermal reduction of vanadium pentoxide (V2O5) in ammonia gas. The process of thermal reduction of V2O5 was optimized by experiments and by modeling of thermodynamic parameters. The obtained V2O3 was characterized by X-ray diffraction, X-ray photoelectron spectrometry, scanning electron microscopy and thermogravimetric analysis. The experimental results indicated that crystal particles of pure V2O3 were successfully synthesized within a short reaction period of 1 h and at a relatively low temperature of 903 K. The content of V2O3 in the product sample higher than 99 wt. %. The grain size of V2O3 ranged from several hundred nanometers to several micrometers. The morphologies of the V2O3 particles were micrometer layers in nanometer sheet structure.

19

A Lifting Wavelet Domain Audio Watermarking Algorithm Based on the Statistical Characteristics of Sub-Band Coefficients

Tao Z., Zhao H., Wu J., Gu J., Xu Y., Wu D.

Archives of Acoustics

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2010

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Vol. 35, No. 4

481-491

EN

In this paper, a new lifting wavelet domain audio watermarking algorithm based on the statistical characteristics of sub-band coefficients is proposed. First of all, an original audio signal was segmented and each segment was divided into two sections. Then, the Barker code was used for synchronization, the LWT (lifting wavelet transform) was performed on each section, a synchronization code and a watermark were embedded into the first section and the second section, respectively, by modifying the statistical average value of the sub-band coefficients. The embed strength was determined adaptively according to the auditory masking property. Experiments show that the embedded watermark has better robustness against common signal processing attacks than present algorithms based on LWT and can resist random cropping in particular.

20

Hydrophilic-interaction liquid chromatography (HILIC) with dad and mass spectroscopic detection for direct analysis of glyphosate and glufosinate residues and for product quality control

Li X., Xu J., Jiang Y., Chen L, Xu Y., Pan C.

Acta Chromatographica

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2009

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Vol. 21, no. 4

559--576

EN

High-performance liquid chromatography with a hydrophilic-interaction liquid chromatographic (HILIC) column has been successfully used to retain and separate the polar phosphonic herbicides glyphosate and glufosinate. Online electrospray tandem ion-trap mass spectrometric and DAD detection were used. The effects on the separation of mobile phase acetonitrile content, buffer concentration, and flow rate, and of column temperature, were investigated. With UV-visible detection at 195 nm, LOQ were <850 mg kg -1, showing the method is suitable for product quality control of these herbicides alone or in combination. Tandem mass spectrometric conditions were optimized for ion-trap detection. Quantification was by use of selected reaction monitoring transitions m / z 168 → 150 in negative-ion mode for glyphosate and m / z 182 → 136 in positive-ion mode for glufosinate. Limits of detection (LOD; S / N > 3) were 0.20 and 0.16 ng for glyphosate and glufosinate, respectively, and the respective limits of quantification (LOQ; S / N = 10) were 0.02 and 0.05 mg kg -1 . Sample derivatization was not necessary to achieve low detection limits in residue analysis in this study. Recovery from watermelon, spinach, potato, tomato, radish-root, and water fortified with the herbicides ranged from 63.6 to 107.3% and relative standard deviations were <15.3%.