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1

M-estimation of the mixed-type generalized linear model

Dong Y., Song L., Wang M., Amin M.

Probability and Mathematical Statistics

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2018

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Vol. 38, Fasc. 1

209--223

EN

To investigate the features of the individual from the mixed-type model, a novel model, named the mixed-type generalized linear model, is proposed firstly in this work, which is verified to be realistic and useful. We consider the robustness of M-estimation to estimate the unknown parameters of the mixed-type generalized linear model. By applying the law of large numbers and the central limit theorem, the consistency and asymptotic normality of the M-estimation for the mixed-type generalized linear model are proved with regularity assumptions. At last, in order to evaluate the finite sample performance of the estimator for the new model, several applied instances are presented, which show the good performance of the estimator.

2

Multi-parameter measurement under fiber bending based on directional resonance coupling in photonic crystal fibers

Tan C., Wang Q., Ding Y., Li H.-W., Wang M., Liu H.

Optica Applicata

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2018

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Vol. 48, nr 3

449--462

EN

A multi-parameter sensor with enhanced sensitivity based on magnetic fluids infiltrated photonic crystal fiber is proposed. The sensing performances are investigated using the mode coupling theory and finite element method. Four symmetrical defective channels are assembled into the photonic crystal fiber to produce two resonant transmission dips λCV and λCH in vertical and horizontal directions, respectively. Each dip can be split into two relatively shallow dips (λCV1, λCV2 or λCH1, λCH2) when the photonic crystal fiber is bent. Interestingly, the values of (λCH2 – λCH1) and (λCV2 – λCV1) are associated with corresponding bend-curvature but almost unaffected by external temperature or magnetic field. On the contrary, the values of (λCH2 + λCH1)/2 and (λCV2 + λCV1)/2 are sensitive to temperature or magnetic field regardless of the bending condition. Based on above characteristics and the dependence of the magnetic fluids refractive index on temperature and magnetic field, the proposed sensor can measure not only the bend-curvature and bend-direction, but also the temperature and magnetic field.

3

Evaluation of genetic diversity and population structure of five yellow catfish Pelteobagrus fulvidraco populations by microsatellite markers

Zhong L., Wang M., Pan J., Li D., Tang S., Bian W., Chen X.

Oceanological and Hydrobiological Studies

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2018

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Vol. 47, No. 2

99--106

EN

Yellow catfish, Pelteobagrus fulvidraco, is an important commercial freshwater species in China. Knowledge about the genetic diversity of the yellow catfish is important to support the management and conservation programs, which would subsequently support the sustainable production of this species. To investigate the genetic diversity and the structure of yellow catfish in the middle and lower reaches of the Yangtze River, 125 individuals from five lakes were genotyped using 13 microsatellite markers. Moderate genetic diversity was determined in all populations, with the observed heterozygosity (HO) ranging from 0.42 to 0.49 and the expected heterozygosity (HE) ranging from 0.51 to 0.61. Low to moderate genetic differentiation among the populations was revealed from pairwise FST values (p < 0.05), as well as from analysis of molecular variance (AMOVA). The UPGMA dendrogram and Bayesian clustering analysis indicated a correlation between genetic differences and geographic distance – four populations from the lower reaches clustered together, whereas the Poyang Lake (PY) population formed a separate cluster. The present study would be helpful in the wild stock management and artificial propagation programs for yellow catfish in the middle and lower reaches of the Yangtze River.

4

The effects of anisotropy of marine magnetic anomalies on the Curie point depth estimates from spectral analysis

Wang M., Liu Z.

Acta Geophysica

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2018

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Vol. 66, no. 5

1019--1030

EN

Azimuthally averaged power spectra are widely used in the Curie point depth (CPD) estimation with the implicit assumption that the magnetization distribution is random and uncorrelated. However, the marine magnetic anomalies are caused by bands of normal and reverse magnetization and show obvious trends. To investigate the effects of the anisotropy of marine magnetic anomalies on the CPD estimates, we develop 3D fractal striped magnetization models to produce lineated marine magnetic anomalies for the first time. We analyze the spectra anisotropy of the lineated magnetic anomalies of the synthetic fractal striped magnetization models and investigate its effects on the CPD estimates. The synthetic models and actual data show that the spectra of the lineated marine magnetic anomalies are directionally anisotropic. The amplitude response is strong and the slope of the logarithmic spectrum is large in a direction perpendicular to the stripes of magnetic anomalies, whereas the amplitude response is weak and the slope of the logarithmic spectrum is small in a direction parallel to the stripes of magnetic anomalies. The depth estimates in the perpendicular direction are close to the actual values, whereas the depths estimates in the parallel direction are significantly lower than the actual values. The actual marine magnetic anomalies of the South China Sea exhibit an anisotropic power spectrum that is consistent with the spectral anisotropy of magnetic anomalies of the synthetic fractal striped magnetization models.

5

Regularized inversion of amplitude‑versus‑incidence angle (AVA) based on a piecewise‑smooth model

Li Z., Wang M., Xu F.

Acta Geophysica

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2018

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Vol. 66, no. 6

1383--1396

EN

Different from the stacked seismic data, pre-stack data includes abundant information about shear wave and density. Through inversing the shear wave and density information from the pre-stack data, we can determine oil-bearing properties from different incident angles. The state-of-the-art inversion methods obtain either low vertical resolution or lateral discontinuities. However, the practical reservoir generally has sharp discontinuities between different layers in vertically direction and is horizontally smooth. Towards obtaining the practical model, we present an inversion method based on the regularized amplitude-versus-incidence angle (AVA) data to estimate the piecewise-smooth model from pre-stack seismic data. This method considers subsurface stratum as a combination of two parts: a piecewise smooth part and a constant part. To fix the ill-posedness in the inversion, we adopt four terms to define the AVA inversion misfit function: the data misfit itself, a total variation regularization term acting as a sparsing operator for the piecewise constant part, a Tikhonov regularization term acting as a smoothing operator for the smooth part, and the last term to smoothly incorporate a priori information for constraining the magnitude of the estimated model. The proposed method not only can incorporate structure information and a priori model constraint, but also is able to derive into a convex objective function that can be easily minimized using iterative approach. Compared with inversion results of TV and Tikhonov regularization methods, the inverted P-wave velocity, S-wave velocity and density of the proposed method can better delineate the piecewise-smooth characteristic of strata.

6

Isolation of quinolone alkaloids from Tetradium ruticarpum via preparative high-speed counter-current chromatography and evaluation of their binding affinities for bovine serum albumin

Zou H., Guo G., Wang M., Huang G.

Acta Chromatographica

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2018

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Vol. 30, no. 2

73--80

EN

By application of preparative high-speed counter-current chromatography (HSCCC) to the crude quinolone alkaloids (1.1 g) from the fruit of Tetradium ruticarpum, 1-methyl-2((6Z,9Z)-pentadecadienyl)-4(1H)-quinolone (1, 8.4 mg), dihydroevocarpine (2, 27.0 mg), and 1-methyl-2-pentadecyl-4(1H)-quinolone (3, 18.8 mg) were isolated in one step with sufficient purity using the solvent system composed of hexane–ethyl acetate–methanol–water (Hex–EtOAc–MeOH–H2O, 5:2:5:3). Further purification of the subfraction was performed by amending the solvent composition and achieved another three quinolone alkaloids, i.e., 1-methyl-2-undecylquinolin-4(1H)-one (4, 13.7 mg), (Z)-1-methyl-2-(tridec-5-en-1-yl) quinolin-4(1H)-one (5, 14.0 mg) from subfraction FR3-A3-85 using Hex–EtOAc–MeOH–H2O (5:3.5:8.75:8.25), and 1-methyl-2-nonylquinolin-4(1H)-one (6, 15.1 mg) from subfraction FR3-A3-36 using Hex–EtOAc–MeOH–H2O (5:3.8:5:4.8). The relationship between the structure of the six alkaloids and their affinities for bovine serum albumin (BSA) was investigated using fluorescence titration analysis. The length and the presence of double bond of the side chain affected their binding process with BSA. The binding behavior might influence their other biological activities.

7

Visualization investigation on the marine data with multivariate statistical analysis methods

Li Y., Lu Z., Wang M.

Polish Maritime Research

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2017

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S 2

89--94

EN

Marine information is an important way for us to know and study more about the ocean. Marine data makes the basic of marine information. Because of the huge quantity and diversity of marine data, and at the same time marine data is polyatomic variable, we start with statistical analysis methods to search for the regularity of the marine data. On one hand, we get the aggregate variation functions of the marine data by factor analyzing in aspect of the spatiality. Then we visually describe the marine status of the studied sea area with pre variogram function and post variogram function. On the other hand, we used cluster analysis method to get the verifying rule in time and make visible graphs of the marine data. In this way, we can also supply with the suggestions in classifying the sea seawater quality. The data processing result shows that the suggested methods in this article are both operable and effective. At the same time some reasonable suggestions are given in the article.

8

Climatic Response of Tracheid Features of Picea meyeri Along Altitude Gradient of Luyashan Mountains of North China

Wang M., Jiang Y., Zhang W., Dong M., Kang M., Xu H.

Polish Journal of Ecology

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2017

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Vol. 65, nr 4

345--358

EN

Changing localized environmental conditions along altitude gradients could modify the responses of tree xylem structures to climate variations. To explore how trees adapt to local environment and respond to climate variants, we analysed the variation of Picea meyeri xylem tracheid features and the relationships with climate variables along an altitude gradient (1970, 2240, 2490 and 2650 m above sea level) of the Luyashan Mountains in the North China. The results mainly indicated the following: (1) tracheid number and diameter of P. meyeri showed significant differences among the four sites along the altitude gradient; (2) trees at site 2 (2240 m) and site 3 (2490 m) are similar in age, but the xylem tracheid number and diameter of these trees were significantly different, which may indicate different functional adaptation; (3) the relationships between xylem features' residual chronologies and the monthly climate data were inconsistent along altitude gradients, which indicated that the limiting factor of P. meyeri growth along the altitude gradients, shifted from drought stress at lower altitudes to low-temperature stress at higher altitudes.

9

Effects of preparation methods of mixed calcium and zinc thermal stabilizers derived from dimer fatty acid and tung-oil based C22 triacid on properties of PVC

Li M., Wang M., Li S., Huang K., Mao W., Xia J.

Polish Journal of Chemical Technology

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2017

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Vol. 19, nr 2

78--87

EN

Calcium and zinc salts of dimer fatty acids (DFA-Ca and DFA-Zn) were synthesized using direct neutralization and metathesis technologies, respectively. The adduct of maleic anhydride and methyl eleostearate (MAME) was also converted to the corresponding zinc soap (C22TA-Zn) and calcium soap (C22TA-Ca) by the two different synthetic routes. Mixed Ca/Zn salts between DFA-Ca and DFA-Zn, and between C22TA-Zn and C22TA-Ca were used as thermal stabilizers for poly(vinyl chloride) (PVC). The PVC thermal stability was determined using Congo red test, discoloration test, torque rheological analysis and TGA. Dynamic mechanical properties were also tested. Results indicated that the DFA-Ca/DFA-Zn thermal stabilizer from direct neutralization technology was found to be superior to that of the metathesis product. The C22TA-Ca/C22TA-Zn thermal stabilizer from direct neutralization method had overall superior thermal stability, and displayed modulus and glass transition comparable to that of metathesis product. Direct neutralization method was more excellent and convenient than metathesis technology.

10

One shot profilometry using iterative two-step temporal phase-unwrapping

Du G., Wang M., Zhou C., Si S., Li H., Lei Z., Li Y.

Optica Applicata

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2017

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Vol. 47, nr 1

97--110

EN

This paper reviews two techniques that have been recently published for three-dimensional profilometry and proposes one shot profilometry using iterative two-step temporal phase-unwrapping by combining the composite fringe projection and the iterative two-step temporal phase unwrapping algorithm. In temporal phase unwrapping, many images with different frequency fringe pattern are needed to project, which would take much time. In order to solve this problem, Ochoa proposed a phase unwrapping algorithm based on phase partitions using a composite fringe. However, we found that the fringe order determined through the construction of phase partitions tended to be imprecise. Recently, we proposed an iterative two-step temporal phase unwrapping algorithm, which can achieve high sensitivity and high precision shape measurement. But it needs multiple frames of fringe images which would take much time. In order to take into account both the speed and accuracy of three-dimensional shape measurement, we get a new, and more accurate unwrapping method based on a composite fringe pattern by combining these two techniques. This method not only retains the speed advantage of Ochoa’s algorithm, but also greatly improves its measurement accuracy. Finally, the experimental evaluation is conducted to prove the validity of the proposed method.

11

Improved method for phase wraps reduction in profilometry

Du G., Wang M., Zhou C., Si S., Li H., Lei Z., Li Y.

Optica Applicata

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2017

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Vol. 47, nr 2

295--306

EN

In order to completely eliminate, or greatly reduce the number of phase wraps in 2D wrapped phase map, Gdeisat and co-workers proposed an algorithm, which uses shifting the spectrum towards the origin. But the spectrum can be shifted only by an integer number, meaning that the phase wraps reduction is often not optimal. In addition, Gdeisat’s method will take much time to make the Fourier transform, inverse Fourier transform, select and shift the spectral components. In view of the above problems, we proposed an improved method for phase wraps elimination or reduction. First, the wrapped phase map is padded with zeros, the carrier frequency of the projected fringe is determined by high resolution, which can be used as the moving distance of the spectrum. And then realize frequency shift in spatial domain. So it not only can enable the spectrum to be shifted by a rational number when the carrier frequency is not an integer number, but also reduce the execution time. Finally, the experimental results demonstrated that the proposed method is feasible.

12

Dual reference beam digital off-axis holography for exact suppression of zero-order term and twin image without spectrum loss

Wang M., Wang K., Zheng M., Li F., Wu J.

Optica Applicata

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2017

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Vol. 47, nr 3

435--443

EN

In this paper, we describe an effective approach to suppressing zero-order term and twin image by using pixel-by-pixel multiplication of double holograms in digital off-axis holography. This method records two holograms, respectively, by using the reference waves in different directions. It shows not only a simpler algorithm and easier implementation in experiment, but also exact and complete suppression of the zero-order term and twin image without any spectrum loss of the object in the image reconstruction, particularly when the image and the zero-order term are fairly close to each other. The experimental result approves of the theoretical prediction very well. This approach provides an effective solution to suppressing undesired noises in the digital off-axis holography.

13

A theoretical derivation of the dilatancy equation for brittle rocks based on Maxwell model

Li J., Huang H., Wang M.

Acta Geophysica

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2017

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Vol. 65, no. 1

55--64

EN

In this paper, the micro-cracks in the brittle rocks are assumed to be penny shaped and evenly distributed; the damage and dilatancy of the brittle rocks is attributed to the growth and expansion of numerous micro-cracks under the local tensile stress. A single crack’s behaviour under the local tensile stress is generalized to all cracks based on the distributed damage mechanics. The relationship between the local tensile stress and the external loading is derived based on the Maxwell model. The damage factor corresponding to the external loading is represented using thep–alpha (p–α) model. A dilatancy equation that can build up a link between the external loading and the rock dilatancy is established. A test of dilatancy of a brittle rock under triaxial compression is conducted; the comparison between experimental results and our theoretical results shows good consistency.

14

Shrinkage Porosity Criterion and Its Application to A 5.5 Ton Steel Ingot

Zhang C., Bao Y., Wang M., Zhang L.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 2

27--32

EN

In order to predict the distribution of shrinkage porosity in steel ingot efficiently and accurately, a criterion R√L and a method to obtain its threshold value were proposed. The criterion R√L was derived based on the solidification characteristics of steel ingot and pressure gradient in the mushy zone, in which the physical properties, the thermal parameters, the structure of the mushy zone and the secondary dendrite arm spacing were all taken into consideration. The threshold value of the criterion R√L was obtained with combination of numerical simulation of ingot solidification and total solidification shrinkage rate. Prediction of the shrinkage porosity in a 5.5 ton ingot of 2Cr13 steel with criterion R√L>0.21 m･℃1/2･s-3/2 agreed well with the results of experimental sectioning. Based on this criterion, optimization of the ingot was carried out by decreasing the height-to-diameter ratio and increasing the taper, which successfully eliminated the centreline porosity and further proved the applicability of this criterion.

15

A New Fuzzy Iterative Learning Control Algorithm for Single Joint Manipulator

Wang M., Bian G., Li H.

Archives of Control Sciences

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2016

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Vol. 26, no. 3

297--310

EN

This paper present a new fuzzy iterative learning control design to solve the trajectory tracking problem and performing repetitive tasks for rigid robot manipulators. Several times’ iterations are needed to make the system tracking error converge, especially in the first iteration without experience. In order to solve that problem, fuzzy control and iterative learning control are combined, where fuzzy control is used to tracking trajectory at the first learning period, and the output of fuzzy control is recorded as the initial control inputs of ILC. The new algorithm also adopts gain self-tuning by fuzzy control, in order to improve the convergence rate. Simulations illustrate the effectiveness and convergence of the new algorithm and advantages compared to traditional method.

16

A Theoretical Explanation for Rock Core Disking in Triaxial Unloading Test by Considering Local Tensile Stress

Huang H., Fan P., Li J., Wang M., Rong X.

Acta Geophysica

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2016

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Vol. 64, no. 5

1430--1445

EN

Rock is a typical inhomogeneous material with a large number of flaws in different scales; the stress field of the rock in its elastic state consists of two parts: the elastic stress, which distributes uniformly in the entire region; and an additional stress, which only exists around the flaws. Theoretical expressions of the additional stress and local stress are derived based on the Maxwell model. Core disking which takes place under the condition that the axial stress is rapidly reduced while the confining pressure is kept unchanged is explained with a new method. Unloading duration’s effect on core disking is analyzed. A new criterion for core disking is presented based on attributing the core disking to the result of the exceedance of local tensile stress over the tensile strength. Based on our theoretical analysis and the conclusions from published resources, core disking is most likely to occur if the maximum principal stress is more than five to six times the tensile strength.

17

Adaptative strategy of leaf traits to drought conditions: Quercus aliena var. acuteserrata forest (The Qinling Mts. China)

Wang M., Wan P., Chai Y., Guo Y., Zhang X., Yue M.

Polish Journal of Ecology

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2015

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Vol. 63, nr 1

77--87

EN

In a climax community where all species are sharing relatively similar and stable habitat, there are differences in leaf traits between deciduous trees and shrubs and dominant species and companion species, especially in leaf lifespan (LLs). What are the differences of relationships among leaf traits between deciduous trees and shrubs? What are the mechanisms of this phenomenon? Here, we presented a one-year observation and recorded the LLs followed a modified method in a Quercus aliena var. acuteserrata forest in the north slope of the Qinling Mountains, China. We found that (i) Different species in the same stand performed quite differently in their LLs (P <0.005). Average LLs of shrubs was slightly longer (P = 0.05) than that of deciduous trees. (ii) LLs showed a significant negative correlation with specific leaf area (SLA) and leaf nitrogen content (LNC) (P <0.05) in deciduous trees, however, a significant positive correlation with LNC and leaf carbon content (LCC) (P <0.05) was detected in shrubs. (iii) The comparison of the traits between dominant and companion species in arbor layer and shrub layer showed that there was no significant difference in LLs, LCC and LNC, except SLA in arbor layer. Our study indicated that the amount of light, at the community scale, might be a main factor determining the LLs of wood plants in deciduous forest. The difference between trees and shrubs in relationships among leaf traits suggests that deciduous trees and shrubs may take different strategies to adapt to the environment. SLA is likely to be a marker trait to distinguish dominant and companion species in arbor layer of deciduous broad leaved forest

18

Uniqueness and parameter dependence of positive doubly periodic solutions of nonlinear telegraph equations

Graef J. R., Kong L., Wang M.

Opuscula Mathematica

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2014

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Vol. 34, no. 2

363--373

EN

The authors study a type of second order nonlinear telegraph equation. The existence and uniqueness of positive doubly periodic solutions are discussed. The parametric dependence of the solutions is also investigated. Two examples are given as applications of the results.

19

Comparison and Analysis of Magnetic-Geared Permanent Magnet Electrical Machine at No-Load

Liu X., Chen D., Yi L., Zhang Ch., Wang M.

Archives of Electrical Engineering

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2014

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Vol. 63, nr 4

683--692

EN

Magnetic-geared permanent magnet (MGPM) electrical machine is a new type of machine by incorporating magnetic gear into PM electrical machine, and it may be in operation with low-speed, high-torque and direct-driven. In this paper, three types of MGPM machines are present, and a quantitative comparison among them is performed by finite element analysis (FEA). The magnetic field distribution, stable torque and back EMF are obtained at no-load. The results show that three types of MGPM machine are suitable for different application fields respectively according to their own advantages, such as high torque and back EMF, which form an important foundation for MGPM electrical machine research.

20

Development of Distributed On-line Monitoring System for Dielectric Loss Tangent of High Voltage Capacitive Apparatus

Gao Q., Sheng G., Zhong D., Wang M., Liu Y., Jiang X.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3a

145--148

EN

This paper presents a distributed measuring system for on-line monitoring of dielectric loss factor tan δ, and capacitance of HV apparatus. The method employs the Discrete Fourier Transform (DFT) which is performed on the scaled down analog voltage and current signals obtained using digital signal processing (DSP) technology. The measuring unit of the on-line monitoring system takes a series of measures in the hardware circuit design to improve the effectiveness of the DFT algorithm. The lab test results of measuring unit show that the measuring unit has high precision of measurement based on the DFT method. Field tests at a regional substation to evaluate the insulation of two groups of 220kV current transformer units using the developed system.

PL

W artykule opisano system pomiaru rozproszonego do monitorowania on-line współczynnika strat dielektrycznych i pojemności w aparatach HV. W metodzie wykorzystano Dyskretną Transformatę Fouriera. W celu poprawy dokładności i skuteczności DFT, dokonywana jest seria pomiarów. Wyniki badań laboratoryjnych oraz w rzeczywistej podstacji, wykazały wysoką precyzję rozwiązania.