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1

A novel DOPO-g-KH550 modification wood fibers and its effects on the properties of composite phenolic foams

Ma Y., Geng X., Zhang X., Wang C., Chu F.

Polish Journal of Chemical Technology

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2018

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Vol. 20, nr 2

47--53

EN

A novel 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) graft γ-amino propyl triethoxy silane (KH550) was synthesized and introduced on the surface of wood fi ber. Finally DOPO-g-KH550 treated wood fi ber (DKTWF) was used to prepare DKTWF composite phenolic foams (DKTWFCPF). The structures of DOPO-g- KH550 was acknowledged by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1 H-NMR). The structures of DKTWF were confirmed by FT-IR. Compared with wood fi ber, the diffraction peaks’ position was basically unchanged, but the crystallinity was slightly increased and thermal stability were dramatically improved, T5% and Tmax increased by 21.9° and 36.1° respectively. But the char yield (800°) was slightly reduced. With the dosage of DKWF, there were different degrees of improvement including the mechanical properties, flame retardancy and microstructure of DKTWFCPF. Comprehensive analysis, the interfacial compatibility was signifi cantly improved between DKTWF and phenolic resin, and the suitable content of DKTWF was 4%.

2

Model construction and experimental verification of the equivalent elastic modulus of a double-helix wire rope

Chen H. Y., Zhang K., Bai Y. X., Ma Y., Deng H. Z.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 4

951--960

EN

To accurately describe mechanical properties of a complex wire rope, a double-helix wire rope is used as an example in this study. According to the spatial structure characteristics of the central helical line of each wire rope, the spatial configuration curve for the double- -helix wire rope is obtained by using differential geometry theory. On the basis of this curve, the mathematical model of the equivalent elastic modulus of the wire rope is developed, and the elastic modulus of a 6×7+IWS wire rope is measured using a universal tensile testing machine. The experimental results are compared with the predicted results to verify correctness of the elastic modulus prediction of the double-helix wire rope.

3

A novel reliability model for multi-component systems subject to multiple dependent competing risks with degradation rate acceleration

Zhang Y., Ma Y., Liu L., Ouyang L.

Eksploatacja i Niezawodność

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2018

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Vol. 20, no. 4

579--589

EN

The purpose of this paper is to establish a new reliability model of the system subject to multiple dependent competing risks. For a system subject to multiple dependent competing risks, the total degradation consists of natural degradation amount and sudden degradation increments (SDIs) caused by random shocks arriving at the system. Most researchers on this topic only focus on the SDIs. However, the impact of random shocks on degradation rate is ignored. In this paper, a novel reliability model considering degradation rate acceleration (DRA) caused by random shocks is proposed, in which the degradation model is based on the degradation path. The dependence relationship between multiple degradation processes is dealt with by copula method, and the arrival time of shocks is assumed to follow a non-homogeneous Poisson process (NHPP). Finally, the effectiveness of the proposed reliability model is demonstrated by an example of a series system. Moreover, the effect of model parameters is evaluated through sensitivity analysis.

PL

Celem niniejszej pracy było stworzenie nowego modelu niezawodności systemu narażonego na liczne zależne ryzyka konkurujące. W przypadku systemu eksponowanego na wiele zależnych ryzyk konkurujących, na wartość całkowitą degradacji składa się wartość degradacji naturalnej oraz wartość nagłych przyrostów degradacji (sudden degradation increments, SDI) powodowanych przez losowe zaburzenia systemu. Większość badaczy tej tematyki koncentruje się wyłącznie na SDI, ignorując tym samym wpływ zaburzeń losowych na tempo degradacji. W niniejszym artykule zaproponowano nowy model niezawodności uwzględniający przyspieszenie tempa degradacji powodowane zaburzeniami losowymi, w którym model degradacji opiera się na krzywej degradacji. Zależność między mnogimi procesami degradacji rozpatrywano za pomocą metody funkcji kopuły przy założeniu, że czas wystąpienia zaburzenia odpowiada niejednorodnemu procesowi Poissona. Skuteczność proponowanego modelu niezawodności zademonstrowano na przykładzie systemu szeregowego. Ponadto, wykorzystano analizę czułości do oceny wpływu parametrów modelu na niezawodność systemu.

4

Simultaneous determination of eight kinds of gingerols in zingiberis rhizome collected from different areas of China

Wang Y., Chen J., Li Y., Li P., Iqbal J., Chen Y., Ma Y., Zhang C.

Acta Chromatographica

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2018

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Vol. 30, no. 3

164--168

EN

A reliable and rapid high-performance liquid chromatography coupled with diode array detector method (HPLC–DAD) was established and validated to determine eight gingerol simultaneously in the rhizomes of Zingiber offcinale Rosc. The separation of eight compounds (4-hydroxy-3-methoxy-benzenebutanol,3,5-dihydroxy-1-(4-hydroxy-3-methoxyphenyl) decane, 3,5-dihydroxy-1-(3,4-dimethoxyphenyl) decane, 6-gingerol, 8-gingerol, 6-shogaol, 5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-1,4-decadien-3-one, and 10-gingerol) were performed on an Agilent TC(2) C18 (250 mm × 4.6 mm, 5 μm) at 30 °C using acetonitrile (A) and 1% formic acid aqueous solution (B) as the mobile phase with gradient elution (0–10 min, 20%–35% A; 10–28 min, 35%–55% A; 28–35 min, 55%–60% A; 35–55 min, 60%–70% A; 55.01–60 min, 100%–100% A). The detection wavelength was set at 280 nm, and the flow rate was 0.8 mL/min. Validation of the analytical method was performed by linearity, precision, and accuracy test. All compounds were quantified with good linear calibration curves (coefficient of determination R2, >0.9999). The method showed good precision with overall coefficients of variation between 0.56% and 0.84%. The range of recovery was from 95.50% to 104.14% for the analytes. This method was successfully applied to quantify eight gingerols in Z. offcinale Rosc from different regions in China, so it can provide quality assessment for this medicine.

5

The structure and properties of eucalyptus fiber/phenolic foam composites under N-β(aminoethyl)-γ-aminopropyl trimethoxy silane pretreatments

Ma Y., Wang C., Chu F.

Polish Journal of Chemical Technology

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2017

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Vol. 19, nr 4

116--121

EN

Eucalyptus fibers were modified with N-β(aminoethyl)-γ-aminopropyl trimethoxy silane to research the fiber surface’s changes and the influence of the treatment on the mechanical properties, flame resistance, thermal conductivity and microstructure of eucalyptus fiber composite phenolic foams (EFCPFs). The results showed that the partial of hemicelluloses, waxes, lignin and impurities from the fiber surface were dissolved and removed. Compared with untreated EFCPFs, the mechanical properties of treated EFCPFs were increased dramatically; The size of cells was smaller and the distribution was more uniform; The thermal conductivities were basically reduced; Especially the ratio of mass loss decreased obviously. However limited oxygen indexs (LOIs) reduced. And the mechanical properties and LOIs of EFCPFs were basically decreased with the increase of eucalyptus fibers. By comprehensive analysis, the results showed that the interfacial compatibility has been significantly improved between eucalyptus fibers and phenolic resin. And the suitable dosage of eucalyptus fibers was about 5%.

6

Actuator failure compensation for two linked 2WD mobile robots based on multiple-model control

Ma Y., Cocquempot V., El Badaoui El Najjar M., Jiang B.

International Journal of Applied Mathematics and Computer Science

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2017

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Vol. 27, no. 4

763--776

EN

This paper develops a new actuator failure compensation scheme for two linked two-wheel drive (2WD) mobile robots based on multiple-model control. First, a configuration of two linked 2WD robots is described, and their kinematics and dynamics are modeled. Then, a multiple-model based failure compensation scheme is developed to compensate for actuator failures, consisting of a kinematic controller, multiple dynamic controllers and a control switching mechanism, which ensures system stability and asymptotic tracking properties. Finally, simulation results verify the effectiveness of the proposed failure compensation control system.

7

3-D simulation of vertical-axial tidal current turbine

Zhang Z., Ma Y., Jiang J., Liu W., Ma Q.

Polish Maritime Research

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2016

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nr 4

73--83

EN

Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics) method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.

8

Numerical research of the viscous effect of the bilge keel on the damping moment

Deng R., Duan W., Ma S., Ma Y.

Polish Maritime Research

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2015

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S 1

67--74

EN

Bilge keels are effective passive devices in mitigating the rolling motion, and the usage of them covers almost all the sea going vessels. This paper focuses on the viscous effect of the bilge keel, ignored the effect of the free surface and the effect of the ship hull, for the general viscous characteristic of the bilge keel. In order to investigate the viscous effect of the bilge keel on the total damping moment, a special 2 dimensional numerical model, which includes a submerged cylinder with and without bilge keels, is designed for the simulation of forced rolling. Three important factors such as bilge keels width, rolling periods, as well as maximal rolling angles are taken into account, and the viscous flow field around the cylinder is simulated by some codes based on the viscous method in different conditions, in which the three factors are coupled. Verification and validation based on the ITTC method are performed for the cylinder without bilge keels in the conditions of different rolling periods and maximal rolling angles. The primary calculation of damping moment induced by the cylinder with 0mm, 4mm, and 10mm width bilge keels shows some interesting results, and a systematic analysis is conducted. The analysis of the damping moment components suggests there is phase difference between the damping moment induced by the cylinder and the bilge keels, and when the bilge keels width reaches a special size, the total damping moment is mitigated. The calculation of the damping moments induced by the cylinder with some larger bilge keels are also performed, and the results suggest that, the damping moment induced by the bilge keels is increased rapidly and becomes the dominant part in the total damping moment while the width of the bilge keels are increased, but the damping moment induced by the cylinder is not changed significantly. Some illustration of the vortices formation and shedding is included, which is the mechanism of the damping moment caused by the bilge keels. The present work shows an interesting problem, and it is useful for the bilge keel design.

9

T-Rough Approximation Pairs and Covering Based Rough Sets

Zhang X., Zhang Y., Xue Z., Ma Y.

Fundamenta Informaticae

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2015

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Vol. 142, nr 1-4

195--212

EN

The relationships between T-rough sets and covering based rough sets are investigated, and two kinds of generated methods of rough approximation operators from existing rough sets are established. Moreover, applying the aforementioned generated methods of approximation operators, S-rough sets and some new covering-based rough sets are introduced and their basic properties are discussed.

10

Design of Stable Semantic Measurement for Ontology-Based Systems

Ma Y., Shang Y., Lu K.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3a

115--120

EN

Ontology selection is an important challenge in the field of ontology engineering. A feasible solution of ontology selection is to measure and evaluate the candidate ontologies, and further select and reuse the high-quality ontologies from them according to some measurement criteria. In this paper, we designed an ontology measurement system (ONTOM) for measuring the quality of candidate ontologies by integrating our semantic ontology metrics into ONTOM. The experiments show that ONTOM can effective measure the semantic quality of ontologies for ontology reuse.

PL

W artykule przedstawiono system pomiaru ontologii ONTOM, realizujący dwie główne funkcje: pomiar semantyk ontologii oraz określenie parametru jakościowego ontologii. W pierwszym punkcie dokonany jest dobór czynników, które należy uwzględnić w pomiarze. W drugim kroku działań chodzi o określenie parametru odzwierciedlającego ontologię danego kandydata. Przedstawiono wyniki badań eksperymentalnych.

11

Analysis of Excitation Current in DC-Biased Transformer by Wavelet Transform

Zhou X., Zhou Z., Ma Y., Wu D.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 5b

108-112

EN

To analyze the excitation current in DC-Biased Transformer in depth, the thesis deduces the mathematical expression of distortion excitation current, and put forwards the analysis method with wavelet transform principle, which directs at analyzing the boundedness of distortion excitation current using the Fourier Transform. Through sampling the distortion excitation current signal, we resolve its wavelet LF approximation signal and HF detail signal, conclude DC component size of the distortion excitation current, confirm the moment of excitation current waveform distorting, comparatively analyze the results after Fourier Transform, and make clear that the principle is feasibility and superiority. Through analyzing the energy spectrogram in the signal high-frequency band of distortion excitation current and short circuit current are determined. Simulation results show that energy changes in the high frequency band among the different scale. In practice, DC bias can lead to the action of relay protection device, which does harm to the system potentially.

PL

Przedstawiono metodę analizy składowej stałej podmagnesowującej w prądzie magnesującym transformatora. Do analizy wykorzystuje się transformatę falkową I transformatę Fouriera prądu magnesującego.

12

Leaf litter decomposition along the temperate - tropical transect (East China) : the influence of stand succession, litter quality and climate

Song X., Jiang H., Peng C., Zhou G., Chang S., Yu S., Ma Y., Peng S., Wei X.

Polish Journal of Ecology

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2012

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Vol. 60, nr 2

265-276

EN

The relationship between litter decomposition and forest succession in addition to the influence of climate variables on the rate of litter decomposition in forest ecosystems are poorly understood. In this study, the effects of forest successional stages, climate, and litter quality on litter decomposition rates were investigated in five sites located in China. The selected sites cover 29 degrees of latitude from 18[degrees]N to 47[degrees]N and spans more than 5,000 km in length along a temperature gradient that transverses across eastern China. This zonal gradient includes five climate zones from temperate to subtropical to tropical zones. Forest types include broad-leaved Korean pine, deciduous broad-leaved, evergreen broad-leaved, monsoon evergreen broad-leaved, and tropical rain forests. The North-South Transect of Eastern China (NSTEC) is one of fifteen international standard transects setup by Global Change and Terrestrial Ecosystems (GCTE). NSTEC is a key component of the International Geosphere-Biosphere Programme (IGBP). The litterbag method was used in this study to determine mass loss and annual decomposition rates of eight tree species (Pinus massoniana Lamb., Cunninghamia lanceolata (Lamb.) Hook., Schima superba Gardn. et Champ., Cinnamomum camphora (L.) Presl., Cyclobalanopsis glauca (Thunb.) Oerst., C. gracilis (Rehd. et Wils.) Cheng et T. Hong, Michelia chapensis Dandy, and Castanopsis eyeri (Champ.) Tutch. through a timeframe starting in May, 2006, and ending in May, 2008. Litterbags 15 x 15 cm and 0.5 x 1.0 mm mesh were filled with 10 g of leaf litter collected from the subtropical forest region and then placed onto the forest floor in triplicate samples for each eight species in all five sites. Three litterbags per species were retrieved from each of the five sites at two month intervals during the two year experimental period. Results suggest that species litter in the climax stage (C. glauca, C. gracilis, and M. chapensis) tended to decompose faster than those in the pioneer stage (P. massoniana and C. lanceolata). Initial phosphorous (P) and nitrogen (N) concentrations of leaf litter were the most critical variables of litter quality in relation to the impact on the rate of litter decomposition. Litter decomposition at different successional stages was found to be directly related to climatic variables such as mean annual precipitation (MAP) and mean annual temperature (MAT). MAP and initial P and N concentrations could therefore be considered good indicators of rates of decomposition.

13

Nitrogen doped carbon nanotubes and curved lamellas produced via pyrolysis of melamine by direct current arc discharge

Zhao R. I., Ma Y., Zhang J., Li F., Liu W., Cui Q.

Materials Science Poland

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2010

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Vol. 28, No. 1

189--198

EN

Nitrogen doped carbon nanostructures, including nanotubes and barrel like curved lamellas, were fabricated via the pyrolysis of a solo precursor, melamine, in a direct current arc discharge. The samples were characterized by elemental analysis, using XRD, XPS, TEM and SEM in parallel. The nitrogen concentration, determined from the elemental analysis, was shown to be lower than 5%. Nitrogen-based functional groups such as pyridine like structures, the pyrrolic or pyridonic structures, N-amine like structures and substitutional nitrogen within the graphene layers, were observed to coexist in the turbostratic carbon matrix. XRD patterns showed characteristic features of turbostratic carbons. TEM analysis of morphologies showed that nanostructures such as tubes and conglomerations of barrel like curved lamellas were present. The formation of bundles of nanotubes was further confirmed by SEM studies. The inhomogeneity in the morphologies of the nanostructures was attributed to the differences in their growth mechanisms.

14

Carbon storage of cycad and other gymnosperm ecosystems in China: implications to evolutionary trends

Ma Y., Jiang H., Wang B., Zhou G., Yu S., Peng S., Hao Y., Wei X., Liu J., Yu Z.

Polish Journal of Ecology

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2009

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Vol. 57, nr 4 (2

635-646

EN

Cycads are an ancient lineage of plants that originated in the Permian, which are vital to the interpretation of plant ecology. The evidence in the fossil records indicates that the morphological and anatomical features of cycads are remarkably similar to the extant taxa, which has been instrumental in our understanding the connections between the early origins of seed plants and their present-day counterparts. The cycad ecosystem is an important vegetation type throughout geological time. Research on the ecological function of the cycad plays a significant role in the study of evolutionary ecology. In this study, we investigated the biomass, productivity and total carbon storage (total of vegetation, litter, and soil carbon) of cycad (Cycas panzhihuaensis L. Zhou et S.Y. Yang) ecosystems in the National C. panzhihuaensis Reserve of China (latitude 26[degrees]37', longitude 101[degrees]35', at 1635 m altitude) by applying the site-standard tree sampling harvest. Cycads are considered to be rare and endangered species, and are in the list of key protected wild plants in the world. The National C. panzhihuaensis Reserve is in Southwestern China, which area approximately 1358 ha, growing approximately 20 000 C. panzhihuaensis individuals. 20 sample plots, each 5 x 5 m were established in the spring of 2006. The mean height of cycads within the stand was 0.44 m and the mean basal diameter was 23.2 cm. The biomass and productivity data for other communities was compiled from references published over the past 20 years throughout China. The biomass and productivity of cycad ecosystems (8.102 [plus or minus] 6.880 t C ha[^-1] and 1.183 [plus or minus] 0.975 t C ha[^-1] yr[^-1], respectively) are smaller than tree fern (Alsophila spinulosa (Wall. ex Hook.) R. M. Tryon) or gymnosperm (Pinaceae, Cupressaceae or Taxodiaceae for representative) ecosystems. The community biomass of Pinaceae-, Cupressaceae- or Taxodiaceae-dominated ecosystems are 6.8, 5.4, and 5.3 times larger than the cycad ecosystem, respectively. The productivity of each is 2.3, 2.8 and 3.8 times larger than the cycad ecosystem. Cycad is an ancient dioecious plant. However, the results show that the differences between the biomass of male and female cycads, as well as the productivity, are not significant.

15

Effect of hadronic rescattering on the elliptic flow after the hydrodynamics model

Ma G., Ma Y., Sa B., Cai X., He Z., Huang H., Long J., Shen W., Zhong Ch., Chen J., Zuo J., Zhang S., Shi X.

Nukleonika

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2006

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Vol. 51,suppl.3

21-27

EN

Abstract A hydrodynamics + hadronic rescattering model is used to simulate Au+Au collisions at 200 GeV and a Cooper-Frye method is adopted for hadronization. The effect of hadronic rescattering on elliptic flow V2 in 20 40% Au+Au collisions at 200 GeV has been investigated. It is found that the hadronic rescattering can suppress elliptic flow V2 and makes an asymmetric system in momentum space tend to be less anisotropic. The suppression effect becomes weak with increasing transverse momentum. In addition, the effect of hadronic rescattering on transverse momentum spectra and anisotropy of hadronic coordinate space is presented.

16

Study on the experiments of the relationship between the geometric dimensions of flexural vibration disk and its vibration characteristics

Yuan Y., Ma Y., Chen M., Wang D., Zhao B.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

255--258

EN

Purpose: The vibration characteristics of flexural vibration disk in ultrasonic honing system were studied systematically through experiments. Design/methodology/approach: The vibration of flexural vibration disk was tested using the acoustic system of ultrasonic honing. Findings: The results showed that the amplitude of vibration disk increases with the reducing of its thickness, when the disk was thin disk (the ratio between the thickness and radius was less than or equal to one fifths) the vibration of disk was flexural vibration, the good vibration effect could be obtained. The maximal amplitudę could reach 20.5μm,at the same time, the number of the wave crests and size could be obtained. There exist amplifying characteristics in the vibration of the disk. When the diameter of disk was not changed, the resonant frequency would decrease with the reducing of the thickness of disk. The resonance could be excited at different frequencies. The corresponding maximal amplitude value provides certain reference value for the dimensional design and application of flexural vibration disk. Research limitations/implications: From analysis, the ratio between diameter and thickness of flexural vibration disk has direct effect on amplitude. The rational diameter and thickness of flexural vibration disk should be selected according to specific machining conditions and the size requirements of the whole honing equipment during the course of design of ultrasonic honing acoustic system. Originality/value: The studied on relationship between geometric dimensions of flexural vibration disk and its vibration characteristics were made.