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1

Wave propagation in functionally graded piezoelectric rods with rectangular cross-section

Yu J. G., Zhang B., Lefebvre J. E., Zhang Ch.

Archives of Mechanics

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2015

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Vol. 67, nr 3

213–-231

EN

For the purpose of design and optimization of functionally graded piezoelectric material (FGPM) transducers, wave propagation in FGPM structures has received much attention in the past twenty years. But research focused essentially on semi-infinite structures and one-dimensional structures, i.e., structures with a finite dimension in only one direction, such as horizontally infinite flat plates and axially infinite hollow cylinders. This paper proposes a double orthogonal polynomial series approach to solve the wave propagation problem in a two-dimensional (2D) FGPM structure, namely, an FGPM rod with a rectangular cross-section. The dispersion curves and electric potential distributions are illustrated.

2

Colloidal crystal cladded microfiber for refractive index sensing

Yan H. T., Zhao X Y, Zhang Ch., Zhen Z Q, Li Q Z, Cao J X, Xia L X

Optica Applicata

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2014

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Vol. 44, nr 2

309--315

EN

We investigate the evanescent field of a microfiber wrapped by colloidal crystals. The microfiber has the diameter of about 1 μm that is drawn from a single-mode fiber with an alcohol lamp. The colloidal spheres are further attached to the microfiber through thermal evaporation, then they self-assemble to crystal-like structures. The 400 nm, 590 nm, and 710 nm-diameter SiO2 colloidal spheres are used, respectively. The spectral responses are studied theoretically and experimentally, and the results agree with each other. It is revealed that the evanescent field of a microfiber could be modulated by the photonic band-gap of colloidal crystals. This characteristic is very useful in refractive index sensing for liquids.

3

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.

4

Preparation of molecularly imprinted polymer for chiral recognition of racemic 1,1′-binaphthalene-2,2′-diamine by HPLC

Dong H., Wang Y., Ou Y., She J., Shen X., Li J., Zhang Ch., Liu L.

Acta Chromatographica

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2014

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Vol. 26, no. 4

683--693

EN

Molecularly imprinted polymers (MIPs) were synthesized by imprinting a new template—S(-)-1,1′-binaphthalene-2,2′-diamine (S-DABN) and applied as chiral stationary phases for chiral separation of DABN racemates by high-performance liquid chromatography (HPLC). The influence of some key factors on the chiral recognition ability of MIPs, such as the type of functional monomers and porogen and the molar ratio of template to monomer, was systematically investigated. The chromatographic conditions, such as mobile phase composition, sample loading, and flow rate, were also measured. The chiral separation for DABN racemates under the optimum chromatographic conditions by using MIP chiral stationary phase (CSP) of P3, prepared with the S-DABN/MAA ratio = 1/4 and used acetonitrile (2 mL) and chloroform (4 mL) as porogen, showed the highest separation factor (2.14). Frontal analysis was used to evaluate affinity to the target molecule of MIPs. The binding sites (Bt) of MIPs and dissociation constant (Kd) were estimated as 4.56 μmol g−1 and 1.40 mmol L−1, respectively. In comparison with the previous studies, this approach had the advantages, such as the higher separation factor, easy preparation, and cost-effectiveness, it not only has the value for research but also has a potential in industrial application.

5

Solid lubricated bearings performance degradation assessment: A fuzzy self-organizing map method

Zhang Ch., Wang S.

Eksploatacja i Niezawodność

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2013

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Vol. 15, no. 4

397--402

EN

Solid lubricated bearings are common components in space mechanisms, and their reliability and performance degradation assessment are very crucial. In this study, a fuzzy self-organizing map method is used to perform performance degradation assessment. Feature vectors are constructed by indices of vibration as well as friction torque signal. Self-organizing map is then used to perform performance degradation assessment and the subjection of each feature vector to normal cluster on output layer is used as degradation indicator. Accelerated life test results show that this method can make effective performance degradation assessment and describe degradation degree in the whole life time.

PL

Łożyska ze smarem stałym to powszechnie stosowane elementy urządzeń, a ich niezawodność i ocena degradacji charakterystyk są bardzo istotne. W przedstawionej pracy wykorzystano metodę rozmytych samoorganizujących się map do oceny obniżenia charakterystyk. Wektory cech skonstruowano za pomocą wskaźników wibracji, jak również sygnału momentu tarcia. Następnie dokonano oceny obniżenia charakterystyk z wykorzystaniem samoorganizującej się mapy, a za wskaźnik degradacji przyjęto przynależność każdego wektora cech do normalnej grupy w warstwie wyjściowej. Wyniki badań przyspieszonych pokazują, że przy użyciu omawianej metody można dokonywać skutecznej oceny obniżenia charakterystyk a także opisywać stopień degradacji w całym okresie eksploatacji.

6

Interaction of Penny-Shaped Crack and Spherical Inclusion in 3D Particulate Elastic Composite: BIEM Calculation of Mode-I Dynamic Stress Intensity Factor

Khay O. M., Mykhaskiv V. V., Sladek J., Sladek Ch., Zhang Ch.

Computer Methods in Materials Science

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2009

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Vol. 9, No. 1

30-36

EN

The interaction between a penny-shaped crack and a spherical elastic inclusion embedded in an infinite elastic matrix subjected to a time-harmonic crack-face loading is investigated. Boundary integral equations (BIEs) are applied for the numerical solution of the problem in the frequency domain. The singularity subtraction and the mapping techniques in conjunction with a collocation scheme are implemented for the regularization and the discretization of the BIEs by taking into account the local structure of the solution at the crack front. As a numerical example, a crack under tensile loading of constant amplitude, where the center of the interacting particle lies in the crack plane, is considered. The reinforcing properties of the inclusion are revealed by the mode-I dynamic stress intensity factor (SIF) as a function of angular coordinate of the crack front for different frequencies and material combinations of the matrix and the inclusion.

PL

Tematem niniejszej pracy jest analiza zależności pomiędzy powstającą szczeliną kołową a sferycznym sprężystym wtrąceniem osadzonym w nieskończonej sprężystej osnowie, poddana jest harmonicznemu obciążeniu w płaszczyźnie pękania. Metoda brzegowych równań całkowych (BIEs) zastosowana do numerycznego rozwiązania problemu w dziedzinie częstotliwości. Eliminacja osobliwości i techniki mapowania są połączone ze schematem kolokacji i zaimplementowane w celu regularyzacji i dyskretyzacji całkowych równań brzegowych poprzez uwzględnienie lokalnej struktury rozwiżania w obszarze wierzchołka pęknięcia. Jako przykład rozważono pęknięcie pojawiające się w warunkach rozciągania ze stałą amplitudą. W ym przypadku środek cząstki leży w płaszczyźnie pęknięcia. Własności wzmacniające wynikające z wtrącenia ujawniają się poprzez dynamiczny współczynnik intensywności naprężenia (SIF) typu-I, który jest funkcją kątową współrzędnej frontu pęknięcia dla różnych częstotliwości i kombinacji materiału osnowy i wtrącenia.

7

A Computational Investigation of a Novel Explosive: DNTF

Zhang Ch., Shu Y., Wang X., Wu X., Zhao X.

Central European Journal of Energetic Materials

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2005

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Vol. 2, nr 2

45-53

EN

Computational investigation including molecular structure, crystal density, heat of formation, relative specific impulse, heat of detonation, detonation velocity and pressure on dinitrofurazanfuroxan (DNTF) was performed by quantum chemistry (density functional theory and Beck 3LYP hybrid density functional with 6-31G (d, p) basis set), molecular mechanics (Dreiding forcefield) and Monte Carlo methods. It can be deduced that DNTF is moderately sensitive and the N9-O10 bond is the weakest in the molecule and the trigger spot of decomposition by the molecular structure analyses. The mean values of the computational results of DNTF are: heats of formation of gas (HOF) and crystal state - 1113.8 and 992.5 kJ mol-1 respectively; heat of detonation (HOD) - 7119.0 kJ kg-1; relative specific impulse vs. HMX - 1.135; detonation velocity and pressure - 9.10 km s-1 and 38.3 GPa respectively. As a result, DNTF is more powerful than HMX and is a promising melt-cast explosive for its possessing high power, moderate sensitivity, low melting point and thermal stability. Additionally, the simulation data is consistent with experiment. So these methods can also be applied to other HEDM (high energetic density materials) designs.